The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]

FreeBSD/Linux Kernel Cross Reference
sys/netgraph/ng_base.c

Version: -  FREEBSD  -  FREEBSD-13-STABLE  -  FREEBSD-13-0  -  FREEBSD-12-STABLE  -  FREEBSD-12-0  -  FREEBSD-11-STABLE  -  FREEBSD-11-0  -  FREEBSD-10-STABLE  -  FREEBSD-10-0  -  FREEBSD-9-STABLE  -  FREEBSD-9-0  -  FREEBSD-8-STABLE  -  FREEBSD-8-0  -  FREEBSD-7-STABLE  -  FREEBSD-7-0  -  FREEBSD-6-STABLE  -  FREEBSD-6-0  -  FREEBSD-5-STABLE  -  FREEBSD-5-0  -  FREEBSD-4-STABLE  -  FREEBSD-3-STABLE  -  FREEBSD22  -  l41  -  OPENBSD  -  linux-2.6  -  MK84  -  PLAN9  -  xnu-8792 
SearchContext: -  none  -  3  -  10 

    1 /*-
    2  * Copyright (c) 1996-1999 Whistle Communications, Inc.
    3  * All rights reserved.
    4  *
    5  * Subject to the following obligations and disclaimer of warranty, use and
    6  * redistribution of this software, in source or object code forms, with or
    7  * without modifications are expressly permitted by Whistle Communications;
    8  * provided, however, that:
    9  * 1. Any and all reproductions of the source or object code must include the
   10  *    copyright notice above and the following disclaimer of warranties; and
   11  * 2. No rights are granted, in any manner or form, to use Whistle
   12  *    Communications, Inc. trademarks, including the mark "WHISTLE
   13  *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
   14  *    such appears in the above copyright notice or in the software.
   15  *
   16  * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
   17  * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
   18  * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
   19  * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
   20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
   21  * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
   22  * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
   23  * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
   24  * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
   25  * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
   26  * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
   27  * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
   28  * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
   29  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   30  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   31  * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
   32  * OF SUCH DAMAGE.
   33  *
   34  * Authors: Julian Elischer <julian@freebsd.org>
   35  *          Archie Cobbs <archie@freebsd.org>
   36  *
   37  * $FreeBSD$
   38  * $Whistle: ng_base.c,v 1.39 1999/01/28 23:54:53 julian Exp $
   39  */
   40 
   41 /*
   42  * This file implements the base netgraph code.
   43  */
   44 
   45 #include <sys/param.h>
   46 #include <sys/systm.h>
   47 #include <sys/ctype.h>
   48 #include <sys/hash.h>
   49 #include <sys/kdb.h>
   50 #include <sys/kernel.h>
   51 #include <sys/kthread.h>
   52 #include <sys/ktr.h>
   53 #include <sys/limits.h>
   54 #include <sys/lock.h>
   55 #include <sys/malloc.h>
   56 #include <sys/mbuf.h>
   57 #include <sys/proc.h>
   58 #include <sys/queue.h>
   59 #include <sys/refcount.h>
   60 #include <sys/rwlock.h>
   61 #include <sys/smp.h>
   62 #include <sys/sysctl.h>
   63 #include <sys/syslog.h>
   64 #include <sys/unistd.h>
   65 #include <machine/cpu.h>
   66 #include <vm/uma.h>
   67 
   68 #include <net/netisr.h>
   69 #include <net/vnet.h>
   70 
   71 #include <netgraph/ng_message.h>
   72 #include <netgraph/netgraph.h>
   73 #include <netgraph/ng_parse.h>
   74 
   75 MODULE_VERSION(netgraph, NG_ABI_VERSION);
   76 
   77 /* Mutex to protect topology events. */
   78 static struct rwlock    ng_topo_lock;
   79 #define TOPOLOGY_RLOCK()        rw_rlock(&ng_topo_lock)
   80 #define TOPOLOGY_RUNLOCK()      rw_runlock(&ng_topo_lock)
   81 #define TOPOLOGY_WLOCK()        rw_wlock(&ng_topo_lock)
   82 #define TOPOLOGY_WUNLOCK()      rw_wunlock(&ng_topo_lock)
   83 #define TOPOLOGY_NOTOWNED()     rw_assert(&ng_topo_lock, RA_UNLOCKED)
   84 
   85 #ifdef  NETGRAPH_DEBUG
   86 static struct mtx       ng_nodelist_mtx; /* protects global node/hook lists */
   87 static struct mtx       ngq_mtx;        /* protects the queue item list */
   88 
   89 static SLIST_HEAD(, ng_node) ng_allnodes;
   90 static LIST_HEAD(, ng_node) ng_freenodes; /* in debug, we never free() them */
   91 static SLIST_HEAD(, ng_hook) ng_allhooks;
   92 static LIST_HEAD(, ng_hook) ng_freehooks; /* in debug, we never free() them */
   93 
   94 static void ng_dumpitems(void);
   95 static void ng_dumpnodes(void);
   96 static void ng_dumphooks(void);
   97 
   98 #endif  /* NETGRAPH_DEBUG */
   99 /*
  100  * DEAD versions of the structures.
  101  * In order to avoid races, it is sometimes necessary to point
  102  * at SOMETHING even though theoretically, the current entity is
  103  * INVALID. Use these to avoid these races.
  104  */
  105 struct ng_type ng_deadtype = {
  106         NG_ABI_VERSION,
  107         "dead",
  108         NULL,   /* modevent */
  109         NULL,   /* constructor */
  110         NULL,   /* rcvmsg */
  111         NULL,   /* shutdown */
  112         NULL,   /* newhook */
  113         NULL,   /* findhook */
  114         NULL,   /* connect */
  115         NULL,   /* rcvdata */
  116         NULL,   /* disconnect */
  117         NULL,   /* cmdlist */
  118 };
  119 
  120 struct ng_node ng_deadnode = {
  121         "dead",
  122         &ng_deadtype,   
  123         NGF_INVALID,
  124         0,      /* numhooks */
  125         NULL,   /* private */
  126         0,      /* ID */
  127         LIST_HEAD_INITIALIZER(ng_deadnode.nd_hooks),
  128         {},     /* all_nodes list entry */
  129         {},     /* id hashtable list entry */
  130         {       0,
  131                 0,
  132                 {}, /* should never use! (should hang) */
  133                 {}, /* workqueue entry */
  134                 STAILQ_HEAD_INITIALIZER(ng_deadnode.nd_input_queue.queue),
  135         },
  136         1,      /* refs */
  137         NULL,   /* vnet */
  138 #ifdef  NETGRAPH_DEBUG
  139         ND_MAGIC,
  140         __FILE__,
  141         __LINE__,
  142         {NULL}
  143 #endif  /* NETGRAPH_DEBUG */
  144 };
  145 
  146 struct ng_hook ng_deadhook = {
  147         "dead",
  148         NULL,           /* private */
  149         HK_INVALID | HK_DEAD,
  150         0,              /* undefined data link type */
  151         &ng_deadhook,   /* Peer is self */
  152         &ng_deadnode,   /* attached to deadnode */
  153         {},             /* hooks list */
  154         NULL,           /* override rcvmsg() */
  155         NULL,           /* override rcvdata() */
  156         1,              /* refs always >= 1 */
  157 #ifdef  NETGRAPH_DEBUG
  158         HK_MAGIC,
  159         __FILE__,
  160         __LINE__,
  161         {NULL}
  162 #endif  /* NETGRAPH_DEBUG */
  163 };
  164 
  165 /*
  166  * END DEAD STRUCTURES
  167  */
  168 /* List nodes with unallocated work */
  169 static STAILQ_HEAD(, ng_node) ng_worklist = STAILQ_HEAD_INITIALIZER(ng_worklist);
  170 static struct mtx       ng_worklist_mtx;   /* MUST LOCK NODE FIRST */
  171 
  172 /* List of installed types */
  173 static LIST_HEAD(, ng_type) ng_typelist;
  174 static struct rwlock    ng_typelist_lock;
  175 #define TYPELIST_RLOCK()        rw_rlock(&ng_typelist_lock)
  176 #define TYPELIST_RUNLOCK()      rw_runlock(&ng_typelist_lock)
  177 #define TYPELIST_WLOCK()        rw_wlock(&ng_typelist_lock)
  178 #define TYPELIST_WUNLOCK()      rw_wunlock(&ng_typelist_lock)
  179 
  180 /* Hash related definitions. */
  181 LIST_HEAD(nodehash, ng_node);
  182 static VNET_DEFINE(struct nodehash *, ng_ID_hash);
  183 static VNET_DEFINE(u_long, ng_ID_hmask);
  184 static VNET_DEFINE(u_long, ng_nodes);
  185 static VNET_DEFINE(struct nodehash *, ng_name_hash);
  186 static VNET_DEFINE(u_long, ng_name_hmask);
  187 static VNET_DEFINE(u_long, ng_named_nodes);
  188 #define V_ng_ID_hash            VNET(ng_ID_hash)
  189 #define V_ng_ID_hmask           VNET(ng_ID_hmask)
  190 #define V_ng_nodes              VNET(ng_nodes)
  191 #define V_ng_name_hash          VNET(ng_name_hash)
  192 #define V_ng_name_hmask         VNET(ng_name_hmask)
  193 #define V_ng_named_nodes        VNET(ng_named_nodes)
  194 
  195 static struct rwlock    ng_idhash_lock;
  196 #define IDHASH_RLOCK()          rw_rlock(&ng_idhash_lock)
  197 #define IDHASH_RUNLOCK()        rw_runlock(&ng_idhash_lock)
  198 #define IDHASH_WLOCK()          rw_wlock(&ng_idhash_lock)
  199 #define IDHASH_WUNLOCK()        rw_wunlock(&ng_idhash_lock)
  200 
  201 /* Method to find a node.. used twice so do it here */
  202 #define NG_IDHASH_FN(ID) ((ID) % (V_ng_ID_hmask + 1))
  203 #define NG_IDHASH_FIND(ID, node)                                        \
  204         do {                                                            \
  205                 rw_assert(&ng_idhash_lock, RA_LOCKED);                  \
  206                 LIST_FOREACH(node, &V_ng_ID_hash[NG_IDHASH_FN(ID)],     \
  207                                                 nd_idnodes) {           \
  208                         if (NG_NODE_IS_VALID(node)                      \
  209                         && (NG_NODE_ID(node) == ID)) {                  \
  210                                 break;                                  \
  211                         }                                               \
  212                 }                                                       \
  213         } while (0)
  214 
  215 static struct rwlock    ng_namehash_lock;
  216 #define NAMEHASH_RLOCK()        rw_rlock(&ng_namehash_lock)
  217 #define NAMEHASH_RUNLOCK()      rw_runlock(&ng_namehash_lock)
  218 #define NAMEHASH_WLOCK()        rw_wlock(&ng_namehash_lock)
  219 #define NAMEHASH_WUNLOCK()      rw_wunlock(&ng_namehash_lock)
  220 
  221 /* Internal functions */
  222 static int      ng_add_hook(node_p node, const char *name, hook_p * hookp);
  223 static int      ng_generic_msg(node_p here, item_p item, hook_p lasthook);
  224 static ng_ID_t  ng_decodeidname(const char *name);
  225 static int      ngb_mod_event(module_t mod, int event, void *data);
  226 static void     ng_worklist_add(node_p node);
  227 static void     ngthread(void *);
  228 static int      ng_apply_item(node_p node, item_p item, int rw);
  229 static void     ng_flush_input_queue(node_p node);
  230 static node_p   ng_ID2noderef(ng_ID_t ID);
  231 static int      ng_con_nodes(item_p item, node_p node, const char *name,
  232                     node_p node2, const char *name2);
  233 static int      ng_con_part2(node_p node, item_p item, hook_p hook);
  234 static int      ng_con_part3(node_p node, item_p item, hook_p hook);
  235 static int      ng_mkpeer(node_p node, const char *name, const char *name2,
  236                     char *type);
  237 static void     ng_name_rehash(void);
  238 static void     ng_ID_rehash(void);
  239 
  240 /* Imported, these used to be externally visible, some may go back. */
  241 void    ng_destroy_hook(hook_p hook);
  242 int     ng_path2noderef(node_p here, const char *path,
  243         node_p *dest, hook_p *lasthook);
  244 int     ng_make_node(const char *type, node_p *nodepp);
  245 int     ng_path_parse(char *addr, char **node, char **path, char **hook);
  246 void    ng_rmnode(node_p node, hook_p dummy1, void *dummy2, int dummy3);
  247 void    ng_unname(node_p node);
  248 
  249 /* Our own netgraph malloc type */
  250 MALLOC_DEFINE(M_NETGRAPH, "netgraph", "netgraph structures and ctrl messages");
  251 MALLOC_DEFINE(M_NETGRAPH_MSG, "netgraph_msg", "netgraph name storage");
  252 static MALLOC_DEFINE(M_NETGRAPH_HOOK, "netgraph_hook",
  253     "netgraph hook structures");
  254 static MALLOC_DEFINE(M_NETGRAPH_NODE, "netgraph_node",
  255     "netgraph node structures");
  256 static MALLOC_DEFINE(M_NETGRAPH_ITEM, "netgraph_item",
  257     "netgraph item structures");
  258 
  259 /* Should not be visible outside this file */
  260 
  261 #define _NG_ALLOC_HOOK(hook) \
  262         hook = malloc(sizeof(*hook), M_NETGRAPH_HOOK, M_NOWAIT | M_ZERO)
  263 #define _NG_ALLOC_NODE(node) \
  264         node = malloc(sizeof(*node), M_NETGRAPH_NODE, M_NOWAIT | M_ZERO)
  265 
  266 #define NG_QUEUE_LOCK_INIT(n)                   \
  267         mtx_init(&(n)->q_mtx, "ng_node", NULL, MTX_DEF)
  268 #define NG_QUEUE_LOCK(n)                        \
  269         mtx_lock(&(n)->q_mtx)
  270 #define NG_QUEUE_UNLOCK(n)                      \
  271         mtx_unlock(&(n)->q_mtx)
  272 #define NG_WORKLIST_LOCK_INIT()                 \
  273         mtx_init(&ng_worklist_mtx, "ng_worklist", NULL, MTX_DEF)
  274 #define NG_WORKLIST_LOCK()                      \
  275         mtx_lock(&ng_worklist_mtx)
  276 #define NG_WORKLIST_UNLOCK()                    \
  277         mtx_unlock(&ng_worklist_mtx)
  278 #define NG_WORKLIST_SLEEP()                     \
  279         mtx_sleep(&ng_worklist, &ng_worklist_mtx, PI_NET, "sleep", 0)
  280 #define NG_WORKLIST_WAKEUP()                    \
  281         wakeup_one(&ng_worklist)
  282 
  283 #ifdef NETGRAPH_DEBUG /*----------------------------------------------*/
  284 /*
  285  * In debug mode:
  286  * In an attempt to help track reference count screwups
  287  * we do not free objects back to the malloc system, but keep them
  288  * in a local cache where we can examine them and keep information safely
  289  * after they have been freed.
  290  * We use this scheme for nodes and hooks, and to some extent for items.
  291  */
  292 static __inline hook_p
  293 ng_alloc_hook(void)
  294 {
  295         hook_p hook;
  296         SLIST_ENTRY(ng_hook) temp;
  297         mtx_lock(&ng_nodelist_mtx);
  298         hook = LIST_FIRST(&ng_freehooks);
  299         if (hook) {
  300                 LIST_REMOVE(hook, hk_hooks);
  301                 bcopy(&hook->hk_all, &temp, sizeof(temp));
  302                 bzero(hook, sizeof(struct ng_hook));
  303                 bcopy(&temp, &hook->hk_all, sizeof(temp));
  304                 mtx_unlock(&ng_nodelist_mtx);
  305                 hook->hk_magic = HK_MAGIC;
  306         } else {
  307                 mtx_unlock(&ng_nodelist_mtx);
  308                 _NG_ALLOC_HOOK(hook);
  309                 if (hook) {
  310                         hook->hk_magic = HK_MAGIC;
  311                         mtx_lock(&ng_nodelist_mtx);
  312                         SLIST_INSERT_HEAD(&ng_allhooks, hook, hk_all);
  313                         mtx_unlock(&ng_nodelist_mtx);
  314                 }
  315         }
  316         return (hook);
  317 }
  318 
  319 static __inline node_p
  320 ng_alloc_node(void)
  321 {
  322         node_p node;
  323         SLIST_ENTRY(ng_node) temp;
  324         mtx_lock(&ng_nodelist_mtx);
  325         node = LIST_FIRST(&ng_freenodes);
  326         if (node) {
  327                 LIST_REMOVE(node, nd_nodes);
  328                 bcopy(&node->nd_all, &temp, sizeof(temp));
  329                 bzero(node, sizeof(struct ng_node));
  330                 bcopy(&temp, &node->nd_all, sizeof(temp));
  331                 mtx_unlock(&ng_nodelist_mtx);
  332                 node->nd_magic = ND_MAGIC;
  333         } else {
  334                 mtx_unlock(&ng_nodelist_mtx);
  335                 _NG_ALLOC_NODE(node);
  336                 if (node) {
  337                         node->nd_magic = ND_MAGIC;
  338                         mtx_lock(&ng_nodelist_mtx);
  339                         SLIST_INSERT_HEAD(&ng_allnodes, node, nd_all);
  340                         mtx_unlock(&ng_nodelist_mtx);
  341                 }
  342         }
  343         return (node);
  344 }
  345 
  346 #define NG_ALLOC_HOOK(hook) do { (hook) = ng_alloc_hook(); } while (0)
  347 #define NG_ALLOC_NODE(node) do { (node) = ng_alloc_node(); } while (0)
  348 
  349 #define NG_FREE_HOOK(hook)                                              \
  350         do {                                                            \
  351                 mtx_lock(&ng_nodelist_mtx);                             \
  352                 LIST_INSERT_HEAD(&ng_freehooks, hook, hk_hooks);        \
  353                 hook->hk_magic = 0;                                     \
  354                 mtx_unlock(&ng_nodelist_mtx);                           \
  355         } while (0)
  356 
  357 #define NG_FREE_NODE(node)                                              \
  358         do {                                                            \
  359                 mtx_lock(&ng_nodelist_mtx);                             \
  360                 LIST_INSERT_HEAD(&ng_freenodes, node, nd_nodes);        \
  361                 node->nd_magic = 0;                                     \
  362                 mtx_unlock(&ng_nodelist_mtx);                           \
  363         } while (0)
  364 
  365 #else /* NETGRAPH_DEBUG */ /*----------------------------------------------*/
  366 
  367 #define NG_ALLOC_HOOK(hook) _NG_ALLOC_HOOK(hook)
  368 #define NG_ALLOC_NODE(node) _NG_ALLOC_NODE(node)
  369 
  370 #define NG_FREE_HOOK(hook) do { free((hook), M_NETGRAPH_HOOK); } while (0)
  371 #define NG_FREE_NODE(node) do { free((node), M_NETGRAPH_NODE); } while (0)
  372 
  373 #endif /* NETGRAPH_DEBUG */ /*----------------------------------------------*/
  374 
  375 /* Set this to kdb_enter("X") to catch all errors as they occur */
  376 #ifndef TRAP_ERROR
  377 #define TRAP_ERROR()
  378 #endif
  379 
  380 static VNET_DEFINE(ng_ID_t, nextID) = 1;
  381 #define V_nextID                        VNET(nextID)
  382 
  383 #ifdef INVARIANTS
  384 #define CHECK_DATA_MBUF(m)      do {                                    \
  385                 struct mbuf *n;                                         \
  386                 int total;                                              \
  387                                                                         \
  388                 M_ASSERTPKTHDR(m);                                      \
  389                 for (total = 0, n = (m); n != NULL; n = n->m_next) {    \
  390                         total += n->m_len;                              \
  391                         if (n->m_nextpkt != NULL)                       \
  392                                 panic("%s: m_nextpkt", __func__);       \
  393                 }                                                       \
  394                                                                         \
  395                 if ((m)->m_pkthdr.len != total) {                       \
  396                         panic("%s: %d != %d",                           \
  397                             __func__, (m)->m_pkthdr.len, total);        \
  398                 }                                                       \
  399         } while (0)
  400 #else
  401 #define CHECK_DATA_MBUF(m)
  402 #endif
  403 
  404 #define ERROUT(x)       do { error = (x); goto done; } while (0)
  405 
  406 /************************************************************************
  407         Parse type definitions for generic messages
  408 ************************************************************************/
  409 
  410 /* Handy structure parse type defining macro */
  411 #define DEFINE_PARSE_STRUCT_TYPE(lo, up, args)                          \
  412 static const struct ng_parse_struct_field                               \
  413         ng_ ## lo ## _type_fields[] = NG_GENERIC_ ## up ## _INFO args;  \
  414 static const struct ng_parse_type ng_generic_ ## lo ## _type = {        \
  415         &ng_parse_struct_type,                                          \
  416         &ng_ ## lo ## _type_fields                                      \
  417 }
  418 
  419 DEFINE_PARSE_STRUCT_TYPE(mkpeer, MKPEER, ());
  420 DEFINE_PARSE_STRUCT_TYPE(connect, CONNECT, ());
  421 DEFINE_PARSE_STRUCT_TYPE(name, NAME, ());
  422 DEFINE_PARSE_STRUCT_TYPE(rmhook, RMHOOK, ());
  423 DEFINE_PARSE_STRUCT_TYPE(nodeinfo, NODEINFO, ());
  424 DEFINE_PARSE_STRUCT_TYPE(typeinfo, TYPEINFO, ());
  425 DEFINE_PARSE_STRUCT_TYPE(linkinfo, LINKINFO, (&ng_generic_nodeinfo_type));
  426 
  427 /* Get length of an array when the length is stored as a 32 bit
  428    value immediately preceding the array -- as with struct namelist
  429    and struct typelist. */
  430 static int
  431 ng_generic_list_getLength(const struct ng_parse_type *type,
  432         const u_char *start, const u_char *buf)
  433 {
  434         return *((const u_int32_t *)(buf - 4));
  435 }
  436 
  437 /* Get length of the array of struct linkinfo inside a struct hooklist */
  438 static int
  439 ng_generic_linkinfo_getLength(const struct ng_parse_type *type,
  440         const u_char *start, const u_char *buf)
  441 {
  442         const struct hooklist *hl = (const struct hooklist *)start;
  443 
  444         return hl->nodeinfo.hooks;
  445 }
  446 
  447 /* Array type for a variable length array of struct namelist */
  448 static const struct ng_parse_array_info ng_nodeinfoarray_type_info = {
  449         &ng_generic_nodeinfo_type,
  450         &ng_generic_list_getLength
  451 };
  452 static const struct ng_parse_type ng_generic_nodeinfoarray_type = {
  453         &ng_parse_array_type,
  454         &ng_nodeinfoarray_type_info
  455 };
  456 
  457 /* Array type for a variable length array of struct typelist */
  458 static const struct ng_parse_array_info ng_typeinfoarray_type_info = {
  459         &ng_generic_typeinfo_type,
  460         &ng_generic_list_getLength
  461 };
  462 static const struct ng_parse_type ng_generic_typeinfoarray_type = {
  463         &ng_parse_array_type,
  464         &ng_typeinfoarray_type_info
  465 };
  466 
  467 /* Array type for array of struct linkinfo in struct hooklist */
  468 static const struct ng_parse_array_info ng_generic_linkinfo_array_type_info = {
  469         &ng_generic_linkinfo_type,
  470         &ng_generic_linkinfo_getLength
  471 };
  472 static const struct ng_parse_type ng_generic_linkinfo_array_type = {
  473         &ng_parse_array_type,
  474         &ng_generic_linkinfo_array_type_info
  475 };
  476 
  477 DEFINE_PARSE_STRUCT_TYPE(typelist, TYPELIST, (&ng_generic_typeinfoarray_type));
  478 DEFINE_PARSE_STRUCT_TYPE(hooklist, HOOKLIST,
  479         (&ng_generic_nodeinfo_type, &ng_generic_linkinfo_array_type));
  480 DEFINE_PARSE_STRUCT_TYPE(listnodes, LISTNODES,
  481         (&ng_generic_nodeinfoarray_type));
  482 
  483 /* List of commands and how to convert arguments to/from ASCII */
  484 static const struct ng_cmdlist ng_generic_cmds[] = {
  485         {
  486           NGM_GENERIC_COOKIE,
  487           NGM_SHUTDOWN,
  488           "shutdown",
  489           NULL,
  490           NULL
  491         },
  492         {
  493           NGM_GENERIC_COOKIE,
  494           NGM_MKPEER,
  495           "mkpeer",
  496           &ng_generic_mkpeer_type,
  497           NULL
  498         },
  499         {
  500           NGM_GENERIC_COOKIE,
  501           NGM_CONNECT,
  502           "connect",
  503           &ng_generic_connect_type,
  504           NULL
  505         },
  506         {
  507           NGM_GENERIC_COOKIE,
  508           NGM_NAME,
  509           "name",
  510           &ng_generic_name_type,
  511           NULL
  512         },
  513         {
  514           NGM_GENERIC_COOKIE,
  515           NGM_RMHOOK,
  516           "rmhook",
  517           &ng_generic_rmhook_type,
  518           NULL
  519         },
  520         {
  521           NGM_GENERIC_COOKIE,
  522           NGM_NODEINFO,
  523           "nodeinfo",
  524           NULL,
  525           &ng_generic_nodeinfo_type
  526         },
  527         {
  528           NGM_GENERIC_COOKIE,
  529           NGM_LISTHOOKS,
  530           "listhooks",
  531           NULL,
  532           &ng_generic_hooklist_type
  533         },
  534         {
  535           NGM_GENERIC_COOKIE,
  536           NGM_LISTNAMES,
  537           "listnames",
  538           NULL,
  539           &ng_generic_listnodes_type    /* same as NGM_LISTNODES */
  540         },
  541         {
  542           NGM_GENERIC_COOKIE,
  543           NGM_LISTNODES,
  544           "listnodes",
  545           NULL,
  546           &ng_generic_listnodes_type
  547         },
  548         {
  549           NGM_GENERIC_COOKIE,
  550           NGM_LISTTYPES,
  551           "listtypes",
  552           NULL,
  553           &ng_generic_typelist_type
  554         },
  555         {
  556           NGM_GENERIC_COOKIE,
  557           NGM_TEXT_CONFIG,
  558           "textconfig",
  559           NULL,
  560           &ng_parse_string_type
  561         },
  562         {
  563           NGM_GENERIC_COOKIE,
  564           NGM_TEXT_STATUS,
  565           "textstatus",
  566           NULL,
  567           &ng_parse_string_type
  568         },
  569         {
  570           NGM_GENERIC_COOKIE,
  571           NGM_ASCII2BINARY,
  572           "ascii2binary",
  573           &ng_parse_ng_mesg_type,
  574           &ng_parse_ng_mesg_type
  575         },
  576         {
  577           NGM_GENERIC_COOKIE,
  578           NGM_BINARY2ASCII,
  579           "binary2ascii",
  580           &ng_parse_ng_mesg_type,
  581           &ng_parse_ng_mesg_type
  582         },
  583         { 0 }
  584 };
  585 
  586 /************************************************************************
  587                         Node routines
  588 ************************************************************************/
  589 
  590 /*
  591  * Instantiate a node of the requested type
  592  */
  593 int
  594 ng_make_node(const char *typename, node_p *nodepp)
  595 {
  596         struct ng_type *type;
  597         int     error;
  598 
  599         /* Check that the type makes sense */
  600         if (typename == NULL) {
  601                 TRAP_ERROR();
  602                 return (EINVAL);
  603         }
  604 
  605         /* Locate the node type. If we fail we return. Do not try to load
  606          * module.
  607          */
  608         if ((type = ng_findtype(typename)) == NULL)
  609                 return (ENXIO);
  610 
  611         /*
  612          * If we have a constructor, then make the node and
  613          * call the constructor to do type specific initialisation.
  614          */
  615         if (type->constructor != NULL) {
  616                 if ((error = ng_make_node_common(type, nodepp)) == 0) {
  617                         if ((error = ((*type->constructor)(*nodepp))) != 0) {
  618                                 NG_NODE_UNREF(*nodepp);
  619                         }
  620                 }
  621         } else {
  622                 /*
  623                  * Node has no constructor. We cannot ask for one
  624                  * to be made. It must be brought into existence by
  625                  * some external agency. The external agency should
  626                  * call ng_make_node_common() directly to get the
  627                  * netgraph part initialised.
  628                  */
  629                 TRAP_ERROR();
  630                 error = EINVAL;
  631         }
  632         return (error);
  633 }
  634 
  635 /*
  636  * Generic node creation. Called by node initialisation for externally
  637  * instantiated nodes (e.g. hardware, sockets, etc ).
  638  * The returned node has a reference count of 1.
  639  */
  640 int
  641 ng_make_node_common(struct ng_type *type, node_p *nodepp)
  642 {
  643         node_p node;
  644 
  645         /* Require the node type to have been already installed */
  646         if (ng_findtype(type->name) == NULL) {
  647                 TRAP_ERROR();
  648                 return (EINVAL);
  649         }
  650 
  651         /* Make a node and try attach it to the type */
  652         NG_ALLOC_NODE(node);
  653         if (node == NULL) {
  654                 TRAP_ERROR();
  655                 return (ENOMEM);
  656         }
  657         node->nd_type = type;
  658 #ifdef VIMAGE
  659         node->nd_vnet = curvnet;
  660 #endif
  661         NG_NODE_REF(node);                              /* note reference */
  662         type->refs++;
  663 
  664         NG_QUEUE_LOCK_INIT(&node->nd_input_queue);
  665         STAILQ_INIT(&node->nd_input_queue.queue);
  666         node->nd_input_queue.q_flags = 0;
  667 
  668         /* Initialize hook list for new node */
  669         LIST_INIT(&node->nd_hooks);
  670 
  671         /* Get an ID and put us in the hash chain. */
  672         IDHASH_WLOCK();
  673         for (;;) { /* wrap protection, even if silly */
  674                 node_p node2 = NULL;
  675                 node->nd_ID = V_nextID++; /* 137/sec for 1 year before wrap */
  676 
  677                 /* Is there a problem with the new number? */
  678                 NG_IDHASH_FIND(node->nd_ID, node2); /* already taken? */
  679                 if ((node->nd_ID != 0) && (node2 == NULL)) {
  680                         break;
  681                 }
  682         }
  683         V_ng_nodes++;
  684         if (V_ng_nodes * 2 > V_ng_ID_hmask)
  685                 ng_ID_rehash();
  686         LIST_INSERT_HEAD(&V_ng_ID_hash[NG_IDHASH_FN(node->nd_ID)], node,
  687             nd_idnodes);
  688         IDHASH_WUNLOCK();
  689 
  690         /* Done */
  691         *nodepp = node;
  692         return (0);
  693 }
  694 
  695 /*
  696  * Forceably start the shutdown process on a node. Either call
  697  * its shutdown method, or do the default shutdown if there is
  698  * no type-specific method.
  699  *
  700  * We can only be called from a shutdown message, so we know we have
  701  * a writer lock, and therefore exclusive access. It also means
  702  * that we should not be on the work queue, but we check anyhow.
  703  *
  704  * Persistent node types must have a type-specific method which
  705  * allocates a new node in which case, this one is irretrievably going away,
  706  * or cleans up anything it needs, and just makes the node valid again,
  707  * in which case we allow the node to survive.
  708  *
  709  * XXX We need to think of how to tell a persistent node that we
  710  * REALLY need to go away because the hardware has gone or we
  711  * are rebooting.... etc.
  712  */
  713 void
  714 ng_rmnode(node_p node, hook_p dummy1, void *dummy2, int dummy3)
  715 {
  716         hook_p hook;
  717 
  718         /* Check if it's already shutting down */
  719         if ((node->nd_flags & NGF_CLOSING) != 0)
  720                 return;
  721 
  722         if (node == &ng_deadnode) {
  723                 printf ("shutdown called on deadnode\n");
  724                 return;
  725         }
  726 
  727         /* Add an extra reference so it doesn't go away during this */
  728         NG_NODE_REF(node);
  729 
  730         /*
  731          * Mark it invalid so any newcomers know not to try use it
  732          * Also add our own mark so we can't recurse
  733          * note that NGF_INVALID does not do this as it's also set during
  734          * creation
  735          */
  736         node->nd_flags |= NGF_INVALID|NGF_CLOSING;
  737 
  738         /* If node has its pre-shutdown method, then call it first*/
  739         if (node->nd_type && node->nd_type->close)
  740                 (*node->nd_type->close)(node);
  741 
  742         /* Notify all remaining connected nodes to disconnect */
  743         while ((hook = LIST_FIRST(&node->nd_hooks)) != NULL)
  744                 ng_destroy_hook(hook);
  745 
  746         /*
  747          * Drain the input queue forceably.
  748          * it has no hooks so what's it going to do, bleed on someone?
  749          * Theoretically we came here from a queue entry that was added
  750          * Just before the queue was closed, so it should be empty anyway.
  751          * Also removes us from worklist if needed.
  752          */
  753         ng_flush_input_queue(node);
  754 
  755         /* Ask the type if it has anything to do in this case */
  756         if (node->nd_type && node->nd_type->shutdown) {
  757                 (*node->nd_type->shutdown)(node);
  758                 if (NG_NODE_IS_VALID(node)) {
  759                         /*
  760                          * Well, blow me down if the node code hasn't declared
  761                          * that it doesn't want to die.
  762                          * Presumably it is a persistent node.
  763                          * If we REALLY want it to go away,
  764                          *  e.g. hardware going away,
  765                          * Our caller should set NGF_REALLY_DIE in nd_flags.
  766                          */
  767                         node->nd_flags &= ~(NGF_INVALID|NGF_CLOSING);
  768                         NG_NODE_UNREF(node); /* Assume they still have theirs */
  769                         return;
  770                 }
  771         } else {                                /* do the default thing */
  772                 NG_NODE_UNREF(node);
  773         }
  774 
  775         ng_unname(node); /* basically a NOP these days */
  776 
  777         /*
  778          * Remove extra reference, possibly the last
  779          * Possible other holders of references may include
  780          * timeout callouts, but theoretically the node's supposed to
  781          * have cancelled them. Possibly hardware dependencies may
  782          * force a driver to 'linger' with a reference.
  783          */
  784         NG_NODE_UNREF(node);
  785 }
  786 
  787 /*
  788  * Remove a reference to the node, possibly the last.
  789  * deadnode always acts as it it were the last.
  790  */
  791 void
  792 ng_unref_node(node_p node)
  793 {
  794 
  795         if (node == &ng_deadnode)
  796                 return;
  797 
  798         CURVNET_SET(node->nd_vnet);
  799 
  800         if (refcount_release(&node->nd_refs)) { /* we were the last */
  801 
  802                 node->nd_type->refs--; /* XXX maybe should get types lock? */
  803                 NAMEHASH_WLOCK();
  804                 if (NG_NODE_HAS_NAME(node)) {
  805                         V_ng_named_nodes--;
  806                         LIST_REMOVE(node, nd_nodes);
  807                 }
  808                 NAMEHASH_WUNLOCK();
  809 
  810                 IDHASH_WLOCK();
  811                 V_ng_nodes--;
  812                 LIST_REMOVE(node, nd_idnodes);
  813                 IDHASH_WUNLOCK();
  814 
  815                 mtx_destroy(&node->nd_input_queue.q_mtx);
  816                 NG_FREE_NODE(node);
  817         }
  818         CURVNET_RESTORE();
  819 }
  820 
  821 /************************************************************************
  822                         Node ID handling
  823 ************************************************************************/
  824 static node_p
  825 ng_ID2noderef(ng_ID_t ID)
  826 {
  827         node_p node;
  828 
  829         IDHASH_RLOCK();
  830         NG_IDHASH_FIND(ID, node);
  831         if (node)
  832                 NG_NODE_REF(node);
  833         IDHASH_RUNLOCK();
  834         return(node);
  835 }
  836 
  837 ng_ID_t
  838 ng_node2ID(node_p node)
  839 {
  840         return (node ? NG_NODE_ID(node) : 0);
  841 }
  842 
  843 /************************************************************************
  844                         Node name handling
  845 ************************************************************************/
  846 
  847 /*
  848  * Assign a node a name.
  849  */
  850 int
  851 ng_name_node(node_p node, const char *name)
  852 {
  853         uint32_t hash;
  854         node_p node2;
  855         int i;
  856 
  857         /* Rename without change is a noop */
  858         if (strcmp(NG_NODE_NAME(node), name) == 0)
  859                 return (0);
  860 
  861         /* Check the name is valid */
  862         for (i = 0; i < NG_NODESIZ; i++) {
  863                 if (name[i] == '\0' || name[i] == '.' || name[i] == ':')
  864                         break;
  865         }
  866         if (i == 0 || name[i] != '\0') {
  867                 TRAP_ERROR();
  868                 return (EINVAL);
  869         }
  870         if (ng_decodeidname(name) != 0) { /* valid IDs not allowed here */
  871                 TRAP_ERROR();
  872                 return (EINVAL);
  873         }
  874 
  875         NAMEHASH_WLOCK();
  876         if (V_ng_named_nodes * 2 > V_ng_name_hmask)
  877                 ng_name_rehash();
  878 
  879         hash = hash32_str(name, HASHINIT) & V_ng_name_hmask;
  880         /* Check the name isn't already being used. */
  881         LIST_FOREACH(node2, &V_ng_name_hash[hash], nd_nodes)
  882                 if (NG_NODE_IS_VALID(node2) &&
  883                     (strcmp(NG_NODE_NAME(node2), name) == 0)) {
  884                         NAMEHASH_WUNLOCK();
  885                         return (EADDRINUSE);
  886                 }
  887 
  888         if (NG_NODE_HAS_NAME(node))
  889                 LIST_REMOVE(node, nd_nodes);
  890         else
  891                 V_ng_named_nodes++;
  892         /* Copy it. */
  893         strlcpy(NG_NODE_NAME(node), name, NG_NODESIZ);
  894         /* Update name hash. */
  895         LIST_INSERT_HEAD(&V_ng_name_hash[hash], node, nd_nodes);
  896         NAMEHASH_WUNLOCK();
  897 
  898         return (0);
  899 }
  900 
  901 /*
  902  * Find a node by absolute name. The name should NOT end with ':'
  903  * The name "." means "this node" and "[xxx]" means "the node
  904  * with ID (ie, at address) xxx".
  905  *
  906  * Returns the node if found, else NULL.
  907  * Eventually should add something faster than a sequential search.
  908  * Note it acquires a reference on the node so you can be sure it's still
  909  * there.
  910  */
  911 node_p
  912 ng_name2noderef(node_p here, const char *name)
  913 {
  914         node_p node;
  915         ng_ID_t temp;
  916         int     hash;
  917 
  918         /* "." means "this node" */
  919         if (strcmp(name, ".") == 0) {
  920                 NG_NODE_REF(here);
  921                 return(here);
  922         }
  923 
  924         /* Check for name-by-ID */
  925         if ((temp = ng_decodeidname(name)) != 0) {
  926                 return (ng_ID2noderef(temp));
  927         }
  928 
  929         /* Find node by name. */
  930         hash = hash32_str(name, HASHINIT) & V_ng_name_hmask;
  931         NAMEHASH_RLOCK();
  932         LIST_FOREACH(node, &V_ng_name_hash[hash], nd_nodes)
  933                 if (NG_NODE_IS_VALID(node) &&
  934                     (strcmp(NG_NODE_NAME(node), name) == 0)) {
  935                         NG_NODE_REF(node);
  936                         break;
  937                 }
  938         NAMEHASH_RUNLOCK();
  939 
  940         return (node);
  941 }
  942 
  943 /*
  944  * Decode an ID name, eg. "[f03034de]". Returns 0 if the
  945  * string is not valid, otherwise returns the value.
  946  */
  947 static ng_ID_t
  948 ng_decodeidname(const char *name)
  949 {
  950         const int len = strlen(name);
  951         char *eptr;
  952         u_long val;
  953 
  954         /* Check for proper length, brackets, no leading junk */
  955         if ((len < 3) || (name[0] != '[') || (name[len - 1] != ']') ||
  956             (!isxdigit(name[1])))
  957                 return ((ng_ID_t)0);
  958 
  959         /* Decode number */
  960         val = strtoul(name + 1, &eptr, 16);
  961         if ((eptr - name != len - 1) || (val == ULONG_MAX) || (val == 0))
  962                 return ((ng_ID_t)0);
  963 
  964         return ((ng_ID_t)val);
  965 }
  966 
  967 /*
  968  * Remove a name from a node. This should only be called
  969  * when shutting down and removing the node.
  970  */
  971 void
  972 ng_unname(node_p node)
  973 {
  974 }
  975 
  976 /*
  977  * Allocate a bigger name hash.
  978  */
  979 static void
  980 ng_name_rehash()
  981 {
  982         struct nodehash *new;
  983         uint32_t hash;
  984         u_long hmask;
  985         node_p node, node2;
  986         int i;
  987 
  988         new = hashinit_flags((V_ng_name_hmask + 1) * 2, M_NETGRAPH_NODE, &hmask,
  989             HASH_NOWAIT);
  990         if (new == NULL)
  991                 return;
  992 
  993         for (i = 0; i <= V_ng_name_hmask; i++)
  994                 LIST_FOREACH_SAFE(node, &V_ng_name_hash[i], nd_nodes, node2) {
  995 #ifdef INVARIANTS
  996                         LIST_REMOVE(node, nd_nodes);
  997 #endif
  998                         hash = hash32_str(NG_NODE_NAME(node), HASHINIT) & hmask;
  999                         LIST_INSERT_HEAD(&new[hash], node, nd_nodes);
 1000                 }
 1001 
 1002         hashdestroy(V_ng_name_hash, M_NETGRAPH_NODE, V_ng_name_hmask);
 1003         V_ng_name_hash = new;
 1004         V_ng_name_hmask = hmask;
 1005 }
 1006 
 1007 /*
 1008  * Allocate a bigger ID hash.
 1009  */
 1010 static void
 1011 ng_ID_rehash()
 1012 {
 1013         struct nodehash *new;
 1014         uint32_t hash;
 1015         u_long hmask;
 1016         node_p node, node2;
 1017         int i;
 1018 
 1019         new = hashinit_flags((V_ng_ID_hmask + 1) * 2, M_NETGRAPH_NODE, &hmask,
 1020             HASH_NOWAIT);
 1021         if (new == NULL)
 1022                 return;
 1023 
 1024         for (i = 0; i <= V_ng_ID_hmask; i++)
 1025                 LIST_FOREACH_SAFE(node, &V_ng_ID_hash[i], nd_idnodes, node2) {
 1026 #ifdef INVARIANTS
 1027                         LIST_REMOVE(node, nd_idnodes);
 1028 #endif
 1029                         hash = (node->nd_ID % (hmask + 1));
 1030                         LIST_INSERT_HEAD(&new[hash], node, nd_idnodes);
 1031                 }
 1032 
 1033         hashdestroy(V_ng_ID_hash, M_NETGRAPH_NODE, V_ng_name_hmask);
 1034         V_ng_ID_hash = new;
 1035         V_ng_ID_hmask = hmask;
 1036 }
 1037 
 1038 /************************************************************************
 1039                         Hook routines
 1040  Names are not optional. Hooks are always connected, except for a
 1041  brief moment within these routines. On invalidation or during creation
 1042  they are connected to the 'dead' hook.
 1043 ************************************************************************/
 1044 
 1045 /*
 1046  * Remove a hook reference
 1047  */
 1048 void
 1049 ng_unref_hook(hook_p hook)
 1050 {
 1051 
 1052         if (hook == &ng_deadhook)
 1053                 return;
 1054 
 1055         if (refcount_release(&hook->hk_refs)) { /* we were the last */
 1056                 if (_NG_HOOK_NODE(hook)) /* it'll probably be ng_deadnode */
 1057                         _NG_NODE_UNREF((_NG_HOOK_NODE(hook)));
 1058                 NG_FREE_HOOK(hook);
 1059         }
 1060 }
 1061 
 1062 /*
 1063  * Add an unconnected hook to a node. Only used internally.
 1064  * Assumes node is locked. (XXX not yet true )
 1065  */
 1066 static int
 1067 ng_add_hook(node_p node, const char *name, hook_p *hookp)
 1068 {
 1069         hook_p hook;
 1070         int error = 0;
 1071 
 1072         /* Check that the given name is good */
 1073         if (name == NULL) {
 1074                 TRAP_ERROR();
 1075                 return (EINVAL);
 1076         }
 1077         if (ng_findhook(node, name) != NULL) {
 1078                 TRAP_ERROR();
 1079                 return (EEXIST);
 1080         }
 1081 
 1082         /* Allocate the hook and link it up */
 1083         NG_ALLOC_HOOK(hook);
 1084         if (hook == NULL) {
 1085                 TRAP_ERROR();
 1086                 return (ENOMEM);
 1087         }
 1088         hook->hk_refs = 1;              /* add a reference for us to return */
 1089         hook->hk_flags = HK_INVALID;
 1090         hook->hk_peer = &ng_deadhook;   /* start off this way */
 1091         hook->hk_node = node;
 1092         NG_NODE_REF(node);              /* each hook counts as a reference */
 1093 
 1094         /* Set hook name */
 1095         strlcpy(NG_HOOK_NAME(hook), name, NG_HOOKSIZ);
 1096 
 1097         /*
 1098          * Check if the node type code has something to say about it
 1099          * If it fails, the unref of the hook will also unref the node.
 1100          */
 1101         if (node->nd_type->newhook != NULL) {
 1102                 if ((error = (*node->nd_type->newhook)(node, hook, name))) {
 1103                         NG_HOOK_UNREF(hook);    /* this frees the hook */
 1104                         return (error);
 1105                 }
 1106         }
 1107         /*
 1108          * The 'type' agrees so far, so go ahead and link it in.
 1109          * We'll ask again later when we actually connect the hooks.
 1110          */
 1111         LIST_INSERT_HEAD(&node->nd_hooks, hook, hk_hooks);
 1112         node->nd_numhooks++;
 1113         NG_HOOK_REF(hook);      /* one for the node */
 1114 
 1115         if (hookp)
 1116                 *hookp = hook;
 1117         return (0);
 1118 }
 1119 
 1120 /*
 1121  * Find a hook
 1122  *
 1123  * Node types may supply their own optimized routines for finding
 1124  * hooks.  If none is supplied, we just do a linear search.
 1125  * XXX Possibly we should add a reference to the hook?
 1126  */
 1127 hook_p
 1128 ng_findhook(node_p node, const char *name)
 1129 {
 1130         hook_p hook;
 1131 
 1132         if (node->nd_type->findhook != NULL)
 1133                 return (*node->nd_type->findhook)(node, name);
 1134         LIST_FOREACH(hook, &node->nd_hooks, hk_hooks) {
 1135                 if (NG_HOOK_IS_VALID(hook) &&
 1136                     (strcmp(NG_HOOK_NAME(hook), name) == 0))
 1137                         return (hook);
 1138         }
 1139         return (NULL);
 1140 }
 1141 
 1142 /*
 1143  * Destroy a hook
 1144  *
 1145  * As hooks are always attached, this really destroys two hooks.
 1146  * The one given, and the one attached to it. Disconnect the hooks
 1147  * from each other first. We reconnect the peer hook to the 'dead'
 1148  * hook so that it can still exist after we depart. We then
 1149  * send the peer its own destroy message. This ensures that we only
 1150  * interact with the peer's structures when it is locked processing that
 1151  * message. We hold a reference to the peer hook so we are guaranteed that
 1152  * the peer hook and node are still going to exist until
 1153  * we are finished there as the hook holds a ref on the node.
 1154  * We run this same code again on the peer hook, but that time it is already
 1155  * attached to the 'dead' hook.
 1156  *
 1157  * This routine is called at all stages of hook creation
 1158  * on error detection and must be able to handle any such stage.
 1159  */
 1160 void
 1161 ng_destroy_hook(hook_p hook)
 1162 {
 1163         hook_p peer;
 1164         node_p node;
 1165 
 1166         if (hook == &ng_deadhook) {     /* better safe than sorry */
 1167                 printf("ng_destroy_hook called on deadhook\n");
 1168                 return;
 1169         }
 1170 
 1171         /*
 1172          * Protect divorce process with mutex, to avoid races on
 1173          * simultaneous disconnect.
 1174          */
 1175         TOPOLOGY_WLOCK();
 1176 
 1177         hook->hk_flags |= HK_INVALID;
 1178 
 1179         peer = NG_HOOK_PEER(hook);
 1180         node = NG_HOOK_NODE(hook);
 1181 
 1182         if (peer && (peer != &ng_deadhook)) {
 1183                 /*
 1184                  * Set the peer to point to ng_deadhook
 1185                  * from this moment on we are effectively independent it.
 1186                  * send it an rmhook message of it's own.
 1187                  */
 1188                 peer->hk_peer = &ng_deadhook;   /* They no longer know us */
 1189                 hook->hk_peer = &ng_deadhook;   /* Nor us, them */
 1190                 if (NG_HOOK_NODE(peer) == &ng_deadnode) {
 1191                         /*
 1192                          * If it's already divorced from a node,
 1193                          * just free it.
 1194                          */
 1195                         TOPOLOGY_WUNLOCK();
 1196                 } else {
 1197                         TOPOLOGY_WUNLOCK();
 1198                         ng_rmhook_self(peer);   /* Send it a surprise */
 1199                 }
 1200                 NG_HOOK_UNREF(peer);            /* account for peer link */
 1201                 NG_HOOK_UNREF(hook);            /* account for peer link */
 1202         } else
 1203                 TOPOLOGY_WUNLOCK();
 1204 
 1205         TOPOLOGY_NOTOWNED();
 1206 
 1207         /*
 1208          * Remove the hook from the node's list to avoid possible recursion
 1209          * in case the disconnection results in node shutdown.
 1210          */
 1211         if (node == &ng_deadnode) { /* happens if called from ng_con_nodes() */
 1212                 return;
 1213         }
 1214         LIST_REMOVE(hook, hk_hooks);
 1215         node->nd_numhooks--;
 1216         if (node->nd_type->disconnect) {
 1217                 /*
 1218                  * The type handler may elect to destroy the node so don't
 1219                  * trust its existence after this point. (except
 1220                  * that we still hold a reference on it. (which we
 1221                  * inherrited from the hook we are destroying)
 1222                  */
 1223                 (*node->nd_type->disconnect) (hook);
 1224         }
 1225 
 1226         /*
 1227          * Note that because we will point to ng_deadnode, the original node
 1228          * is not decremented automatically so we do that manually.
 1229          */
 1230         _NG_HOOK_NODE(hook) = &ng_deadnode;
 1231         NG_NODE_UNREF(node);    /* We no longer point to it so adjust count */
 1232         NG_HOOK_UNREF(hook);    /* Account for linkage (in list) to node */
 1233 }
 1234 
 1235 /*
 1236  * Take two hooks on a node and merge the connection so that the given node
 1237  * is effectively bypassed.
 1238  */
 1239 int
 1240 ng_bypass(hook_p hook1, hook_p hook2)
 1241 {
 1242         if (hook1->hk_node != hook2->hk_node) {
 1243                 TRAP_ERROR();
 1244                 return (EINVAL);
 1245         }
 1246         TOPOLOGY_WLOCK();
 1247         if (NG_HOOK_NOT_VALID(hook1) || NG_HOOK_NOT_VALID(hook2)) {
 1248                 TOPOLOGY_WUNLOCK();
 1249                 return (EINVAL);
 1250         }
 1251         hook1->hk_peer->hk_peer = hook2->hk_peer;
 1252         hook2->hk_peer->hk_peer = hook1->hk_peer;
 1253 
 1254         hook1->hk_peer = &ng_deadhook;
 1255         hook2->hk_peer = &ng_deadhook;
 1256         TOPOLOGY_WUNLOCK();
 1257 
 1258         NG_HOOK_UNREF(hook1);
 1259         NG_HOOK_UNREF(hook2);
 1260 
 1261         /* XXX If we ever cache methods on hooks update them as well */
 1262         ng_destroy_hook(hook1);
 1263         ng_destroy_hook(hook2);
 1264         return (0);
 1265 }
 1266 
 1267 /*
 1268  * Install a new netgraph type
 1269  */
 1270 int
 1271 ng_newtype(struct ng_type *tp)
 1272 {
 1273         const size_t namelen = strlen(tp->name);
 1274 
 1275         /* Check version and type name fields */
 1276         if ((tp->version != NG_ABI_VERSION) || (namelen == 0) ||
 1277             (namelen >= NG_TYPESIZ)) {
 1278                 TRAP_ERROR();
 1279                 if (tp->version != NG_ABI_VERSION) {
 1280                         printf("Netgraph: Node type rejected. ABI mismatch. "
 1281                             "Suggest recompile\n");
 1282                 }
 1283                 return (EINVAL);
 1284         }
 1285 
 1286         /* Check for name collision */
 1287         if (ng_findtype(tp->name) != NULL) {
 1288                 TRAP_ERROR();
 1289                 return (EEXIST);
 1290         }
 1291 
 1292         /* Link in new type */
 1293         TYPELIST_WLOCK();
 1294         LIST_INSERT_HEAD(&ng_typelist, tp, types);
 1295         tp->refs = 1;   /* first ref is linked list */
 1296         TYPELIST_WUNLOCK();
 1297         return (0);
 1298 }
 1299 
 1300 /*
 1301  * unlink a netgraph type
 1302  * If no examples exist
 1303  */
 1304 int
 1305 ng_rmtype(struct ng_type *tp)
 1306 {
 1307         /* Check for name collision */
 1308         if (tp->refs != 1) {
 1309                 TRAP_ERROR();
 1310                 return (EBUSY);
 1311         }
 1312 
 1313         /* Unlink type */
 1314         TYPELIST_WLOCK();
 1315         LIST_REMOVE(tp, types);
 1316         TYPELIST_WUNLOCK();
 1317         return (0);
 1318 }
 1319 
 1320 /*
 1321  * Look for a type of the name given
 1322  */
 1323 struct ng_type *
 1324 ng_findtype(const char *typename)
 1325 {
 1326         struct ng_type *type;
 1327 
 1328         TYPELIST_RLOCK();
 1329         LIST_FOREACH(type, &ng_typelist, types) {
 1330                 if (strcmp(type->name, typename) == 0)
 1331                         break;
 1332         }
 1333         TYPELIST_RUNLOCK();
 1334         return (type);
 1335 }
 1336 
 1337 /************************************************************************
 1338                         Composite routines
 1339 ************************************************************************/
 1340 /*
 1341  * Connect two nodes using the specified hooks, using queued functions.
 1342  */
 1343 static int
 1344 ng_con_part3(node_p node, item_p item, hook_p hook)
 1345 {
 1346         int     error = 0;
 1347 
 1348         /*
 1349          * When we run, we know that the node 'node' is locked for us.
 1350          * Our caller has a reference on the hook.
 1351          * Our caller has a reference on the node.
 1352          * (In this case our caller is ng_apply_item() ).
 1353          * The peer hook has a reference on the hook.
 1354          * We are all set up except for the final call to the node, and
 1355          * the clearing of the INVALID flag.
 1356          */
 1357         if (NG_HOOK_NODE(hook) == &ng_deadnode) {
 1358                 /*
 1359                  * The node must have been freed again since we last visited
 1360                  * here. ng_destry_hook() has this effect but nothing else does.
 1361                  * We should just release our references and
 1362                  * free anything we can think of.
 1363                  * Since we know it's been destroyed, and it's our caller
 1364                  * that holds the references, just return.
 1365                  */
 1366                 ERROUT(ENOENT);
 1367         }
 1368         if (hook->hk_node->nd_type->connect) {
 1369                 if ((error = (*hook->hk_node->nd_type->connect) (hook))) {
 1370                         ng_destroy_hook(hook);  /* also zaps peer */
 1371                         printf("failed in ng_con_part3()\n");
 1372                         ERROUT(error);
 1373                 }
 1374         }
 1375         /*
 1376          *  XXX this is wrong for SMP. Possibly we need
 1377          * to separate out 'create' and 'invalid' flags.
 1378          * should only set flags on hooks we have locked under our node.
 1379          */
 1380         hook->hk_flags &= ~HK_INVALID;
 1381 done:
 1382         NG_FREE_ITEM(item);
 1383         return (error);
 1384 }
 1385 
 1386 static int
 1387 ng_con_part2(node_p node, item_p item, hook_p hook)
 1388 {
 1389         hook_p  peer;
 1390         int     error = 0;
 1391 
 1392         /*
 1393          * When we run, we know that the node 'node' is locked for us.
 1394          * Our caller has a reference on the hook.
 1395          * Our caller has a reference on the node.
 1396          * (In this case our caller is ng_apply_item() ).
 1397          * The peer hook has a reference on the hook.
 1398          * our node pointer points to the 'dead' node.
 1399          * First check the hook name is unique.
 1400          * Should not happen because we checked before queueing this.
 1401          */
 1402         if (ng_findhook(node, NG_HOOK_NAME(hook)) != NULL) {
 1403                 TRAP_ERROR();
 1404                 ng_destroy_hook(hook); /* should destroy peer too */
 1405                 printf("failed in ng_con_part2()\n");
 1406                 ERROUT(EEXIST);
 1407         }
 1408         /*
 1409          * Check if the node type code has something to say about it
 1410          * If it fails, the unref of the hook will also unref the attached node,
 1411          * however since that node is 'ng_deadnode' this will do nothing.
 1412          * The peer hook will also be destroyed.
 1413          */
 1414         if (node->nd_type->newhook != NULL) {
 1415                 if ((error = (*node->nd_type->newhook)(node, hook,
 1416                     hook->hk_name))) {
 1417                         ng_destroy_hook(hook); /* should destroy peer too */
 1418                         printf("failed in ng_con_part2()\n");
 1419                         ERROUT(error);
 1420                 }
 1421         }
 1422 
 1423         /*
 1424          * The 'type' agrees so far, so go ahead and link it in.
 1425          * We'll ask again later when we actually connect the hooks.
 1426          */
 1427         hook->hk_node = node;           /* just overwrite ng_deadnode */
 1428         NG_NODE_REF(node);              /* each hook counts as a reference */
 1429         LIST_INSERT_HEAD(&node->nd_hooks, hook, hk_hooks);
 1430         node->nd_numhooks++;
 1431         NG_HOOK_REF(hook);      /* one for the node */
 1432         
 1433         /*
 1434          * We now have a symmetrical situation, where both hooks have been
 1435          * linked to their nodes, the newhook methods have been called
 1436          * And the references are all correct. The hooks are still marked
 1437          * as invalid, as we have not called the 'connect' methods
 1438          * yet.
 1439          * We can call the local one immediately as we have the
 1440          * node locked, but we need to queue the remote one.
 1441          */
 1442         if (hook->hk_node->nd_type->connect) {
 1443                 if ((error = (*hook->hk_node->nd_type->connect) (hook))) {
 1444                         ng_destroy_hook(hook);  /* also zaps peer */
 1445                         printf("failed in ng_con_part2(A)\n");
 1446                         ERROUT(error);
 1447                 }
 1448         }
 1449 
 1450         /*
 1451          * Acquire topo mutex to avoid race with ng_destroy_hook().
 1452          */
 1453         TOPOLOGY_RLOCK();
 1454         peer = hook->hk_peer;
 1455         if (peer == &ng_deadhook) {
 1456                 TOPOLOGY_RUNLOCK();
 1457                 printf("failed in ng_con_part2(B)\n");
 1458                 ng_destroy_hook(hook);
 1459                 ERROUT(ENOENT);
 1460         }
 1461         TOPOLOGY_RUNLOCK();
 1462 
 1463         if ((error = ng_send_fn2(peer->hk_node, peer, item, &ng_con_part3,
 1464             NULL, 0, NG_REUSE_ITEM))) {
 1465                 printf("failed in ng_con_part2(C)\n");
 1466                 ng_destroy_hook(hook);  /* also zaps peer */
 1467                 return (error);         /* item was consumed. */
 1468         }
 1469         hook->hk_flags &= ~HK_INVALID; /* need both to be able to work */
 1470         return (0);                     /* item was consumed. */
 1471 done:
 1472         NG_FREE_ITEM(item);
 1473         return (error);
 1474 }
 1475 
 1476 /*
 1477  * Connect this node with another node. We assume that this node is
 1478  * currently locked, as we are only called from an NGM_CONNECT message.
 1479  */
 1480 static int
 1481 ng_con_nodes(item_p item, node_p node, const char *name,
 1482     node_p node2, const char *name2)
 1483 {
 1484         int     error;
 1485         hook_p  hook;
 1486         hook_p  hook2;
 1487 
 1488         if (ng_findhook(node2, name2) != NULL) {
 1489                 return(EEXIST);
 1490         }
 1491         if ((error = ng_add_hook(node, name, &hook)))  /* gives us a ref */
 1492                 return (error);
 1493         /* Allocate the other hook and link it up */
 1494         NG_ALLOC_HOOK(hook2);
 1495         if (hook2 == NULL) {
 1496                 TRAP_ERROR();
 1497                 ng_destroy_hook(hook);  /* XXX check ref counts so far */
 1498                 NG_HOOK_UNREF(hook);    /* including our ref */
 1499                 return (ENOMEM);
 1500         }
 1501         hook2->hk_refs = 1;             /* start with a reference for us. */
 1502         hook2->hk_flags = HK_INVALID;
 1503         hook2->hk_peer = hook;          /* Link the two together */
 1504         hook->hk_peer = hook2;  
 1505         NG_HOOK_REF(hook);              /* Add a ref for the peer to each*/
 1506         NG_HOOK_REF(hook2);
 1507         hook2->hk_node = &ng_deadnode;
 1508         strlcpy(NG_HOOK_NAME(hook2), name2, NG_HOOKSIZ);
 1509 
 1510         /*
 1511          * Queue the function above.
 1512          * Procesing continues in that function in the lock context of
 1513          * the other node.
 1514          */
 1515         if ((error = ng_send_fn2(node2, hook2, item, &ng_con_part2, NULL, 0,
 1516             NG_NOFLAGS))) {
 1517                 printf("failed in ng_con_nodes(): %d\n", error);
 1518                 ng_destroy_hook(hook);  /* also zaps peer */
 1519         }
 1520 
 1521         NG_HOOK_UNREF(hook);            /* Let each hook go if it wants to */
 1522         NG_HOOK_UNREF(hook2);
 1523         return (error);
 1524 }
 1525 
 1526 /*
 1527  * Make a peer and connect.
 1528  * We assume that the local node is locked.
 1529  * The new node probably doesn't need a lock until
 1530  * it has a hook, because it cannot really have any work until then,
 1531  * but we should think about it a bit more.
 1532  *
 1533  * The problem may come if the other node also fires up
 1534  * some hardware or a timer or some other source of activation,
 1535  * also it may already get a command msg via it's ID.
 1536  *
 1537  * We could use the same method as ng_con_nodes() but we'd have
 1538  * to add ability to remove the node when failing. (Not hard, just
 1539  * make arg1 point to the node to remove).
 1540  * Unless of course we just ignore failure to connect and leave
 1541  * an unconnected node?
 1542  */
 1543 static int
 1544 ng_mkpeer(node_p node, const char *name, const char *name2, char *type)
 1545 {
 1546         node_p  node2;
 1547         hook_p  hook1, hook2;
 1548         int     error;
 1549 
 1550         if ((error = ng_make_node(type, &node2))) {
 1551                 return (error);
 1552         }
 1553 
 1554         if ((error = ng_add_hook(node, name, &hook1))) { /* gives us a ref */
 1555                 ng_rmnode(node2, NULL, NULL, 0);
 1556                 return (error);
 1557         }
 1558 
 1559         if ((error = ng_add_hook(node2, name2, &hook2))) {
 1560                 ng_rmnode(node2, NULL, NULL, 0);
 1561                 ng_destroy_hook(hook1);
 1562                 NG_HOOK_UNREF(hook1);
 1563                 return (error);
 1564         }
 1565 
 1566         /*
 1567          * Actually link the two hooks together.
 1568          */
 1569         hook1->hk_peer = hook2;
 1570         hook2->hk_peer = hook1;
 1571 
 1572         /* Each hook is referenced by the other */
 1573         NG_HOOK_REF(hook1);
 1574         NG_HOOK_REF(hook2);
 1575 
 1576         /* Give each node the opportunity to veto the pending connection */
 1577         if (hook1->hk_node->nd_type->connect) {
 1578                 error = (*hook1->hk_node->nd_type->connect) (hook1);
 1579         }
 1580 
 1581         if ((error == 0) && hook2->hk_node->nd_type->connect) {
 1582                 error = (*hook2->hk_node->nd_type->connect) (hook2);
 1583 
 1584         }
 1585 
 1586         /*
 1587          * drop the references we were holding on the two hooks.
 1588          */
 1589         if (error) {
 1590                 ng_destroy_hook(hook2); /* also zaps hook1 */
 1591                 ng_rmnode(node2, NULL, NULL, 0);
 1592         } else {
 1593                 /* As a last act, allow the hooks to be used */
 1594                 hook1->hk_flags &= ~HK_INVALID;
 1595                 hook2->hk_flags &= ~HK_INVALID;
 1596         }
 1597         NG_HOOK_UNREF(hook1);
 1598         NG_HOOK_UNREF(hook2);
 1599         return (error);
 1600 }
 1601 
 1602 /************************************************************************
 1603                 Utility routines to send self messages
 1604 ************************************************************************/
 1605         
 1606 /* Shut this node down as soon as everyone is clear of it */
 1607 /* Should add arg "immediately" to jump the queue */
 1608 int
 1609 ng_rmnode_self(node_p node)
 1610 {
 1611         int             error;
 1612 
 1613         if (node == &ng_deadnode)
 1614                 return (0);
 1615         node->nd_flags |= NGF_INVALID;
 1616         if (node->nd_flags & NGF_CLOSING)
 1617                 return (0);
 1618 
 1619         error = ng_send_fn(node, NULL, &ng_rmnode, NULL, 0);
 1620         return (error);
 1621 }
 1622 
 1623 static void
 1624 ng_rmhook_part2(node_p node, hook_p hook, void *arg1, int arg2)
 1625 {
 1626         ng_destroy_hook(hook);
 1627         return ;
 1628 }
 1629 
 1630 int
 1631 ng_rmhook_self(hook_p hook)
 1632 {
 1633         int             error;
 1634         node_p node = NG_HOOK_NODE(hook);
 1635 
 1636         if (node == &ng_deadnode)
 1637                 return (0);
 1638 
 1639         error = ng_send_fn(node, hook, &ng_rmhook_part2, NULL, 0);
 1640         return (error);
 1641 }
 1642 
 1643 /***********************************************************************
 1644  * Parse and verify a string of the form:  <NODE:><PATH>
 1645  *
 1646  * Such a string can refer to a specific node or a specific hook
 1647  * on a specific node, depending on how you look at it. In the
 1648  * latter case, the PATH component must not end in a dot.
 1649  *
 1650  * Both <NODE:> and <PATH> are optional. The <PATH> is a string
 1651  * of hook names separated by dots. This breaks out the original
 1652  * string, setting *nodep to "NODE" (or NULL if none) and *pathp
 1653  * to "PATH" (or NULL if degenerate). Also, *hookp will point to
 1654  * the final hook component of <PATH>, if any, otherwise NULL.
 1655  *
 1656  * This returns -1 if the path is malformed. The char ** are optional.
 1657  ***********************************************************************/
 1658 int
 1659 ng_path_parse(char *addr, char **nodep, char **pathp, char **hookp)
 1660 {
 1661         char    *node, *path, *hook;
 1662         int     k;
 1663 
 1664         /*
 1665          * Extract absolute NODE, if any
 1666          */
 1667         for (path = addr; *path && *path != ':'; path++);
 1668         if (*path) {
 1669                 node = addr;    /* Here's the NODE */
 1670                 *path++ = '\0'; /* Here's the PATH */
 1671 
 1672                 /* Node name must not be empty */
 1673                 if (!*node)
 1674                         return -1;
 1675 
 1676                 /* A name of "." is OK; otherwise '.' not allowed */
 1677                 if (strcmp(node, ".") != 0) {
 1678                         for (k = 0; node[k]; k++)
 1679                                 if (node[k] == '.')
 1680                                         return -1;
 1681                 }
 1682         } else {
 1683                 node = NULL;    /* No absolute NODE */
 1684                 path = addr;    /* Here's the PATH */
 1685         }
 1686 
 1687         /* Snoop for illegal characters in PATH */
 1688         for (k = 0; path[k]; k++)
 1689                 if (path[k] == ':')
 1690                         return -1;
 1691 
 1692         /* Check for no repeated dots in PATH */
 1693         for (k = 0; path[k]; k++)
 1694                 if (path[k] == '.' && path[k + 1] == '.')
 1695                         return -1;
 1696 
 1697         /* Remove extra (degenerate) dots from beginning or end of PATH */
 1698         if (path[0] == '.')
 1699                 path++;
 1700         if (*path && path[strlen(path) - 1] == '.')
 1701                 path[strlen(path) - 1] = 0;
 1702 
 1703         /* If PATH has a dot, then we're not talking about a hook */
 1704         if (*path) {
 1705                 for (hook = path, k = 0; path[k]; k++)
 1706                         if (path[k] == '.') {
 1707                                 hook = NULL;
 1708                                 break;
 1709                         }
 1710         } else
 1711                 path = hook = NULL;
 1712 
 1713         /* Done */
 1714         if (nodep)
 1715                 *nodep = node;
 1716         if (pathp)
 1717                 *pathp = path;
 1718         if (hookp)
 1719                 *hookp = hook;
 1720         return (0);
 1721 }
 1722 
 1723 /*
 1724  * Given a path, which may be absolute or relative, and a starting node,
 1725  * return the destination node.
 1726  */
 1727 int
 1728 ng_path2noderef(node_p here, const char *address, node_p *destp,
 1729     hook_p *lasthook)
 1730 {
 1731         char    fullpath[NG_PATHSIZ];
 1732         char   *nodename, *path;
 1733         node_p  node, oldnode;
 1734 
 1735         /* Initialize */
 1736         if (destp == NULL) {
 1737                 TRAP_ERROR();
 1738                 return EINVAL;
 1739         }
 1740         *destp = NULL;
 1741 
 1742         /* Make a writable copy of address for ng_path_parse() */
 1743         strncpy(fullpath, address, sizeof(fullpath) - 1);
 1744         fullpath[sizeof(fullpath) - 1] = '\0';
 1745 
 1746         /* Parse out node and sequence of hooks */
 1747         if (ng_path_parse(fullpath, &nodename, &path, NULL) < 0) {
 1748                 TRAP_ERROR();
 1749                 return EINVAL;
 1750         }
 1751 
 1752         /*
 1753          * For an absolute address, jump to the starting node.
 1754          * Note that this holds a reference on the node for us.
 1755          * Don't forget to drop the reference if we don't need it.
 1756          */
 1757         if (nodename) {
 1758                 node = ng_name2noderef(here, nodename);
 1759                 if (node == NULL) {
 1760                         TRAP_ERROR();
 1761                         return (ENOENT);
 1762                 }
 1763         } else {
 1764                 if (here == NULL) {
 1765                         TRAP_ERROR();
 1766                         return (EINVAL);
 1767                 }
 1768                 node = here;
 1769                 NG_NODE_REF(node);
 1770         }
 1771 
 1772         if (path == NULL) {
 1773                 if (lasthook != NULL)
 1774                         *lasthook = NULL;
 1775                 *destp = node;
 1776                 return (0);
 1777         }
 1778 
 1779         /*
 1780          * Now follow the sequence of hooks
 1781          *
 1782          * XXXGL: The path may demolish as we go the sequence, but if
 1783          * we hold the topology mutex at critical places, then, I hope,
 1784          * we would always have valid pointers in hand, although the
 1785          * path behind us may no longer exist.
 1786          */
 1787         for (;;) {
 1788                 hook_p hook;
 1789                 char *segment;
 1790 
 1791                 /*
 1792                  * Break out the next path segment. Replace the dot we just
 1793                  * found with a NUL; "path" points to the next segment (or the
 1794                  * NUL at the end).
 1795                  */
 1796                 for (segment = path; *path != '\0'; path++) {
 1797                         if (*path == '.') {
 1798                                 *path++ = '\0';
 1799                                 break;
 1800                         }
 1801                 }
 1802 
 1803                 /* We have a segment, so look for a hook by that name */
 1804                 hook = ng_findhook(node, segment);
 1805 
 1806                 TOPOLOGY_WLOCK();
 1807                 /* Can't get there from here... */
 1808                 if (hook == NULL || NG_HOOK_PEER(hook) == NULL ||
 1809                     NG_HOOK_NOT_VALID(hook) ||
 1810                     NG_HOOK_NOT_VALID(NG_HOOK_PEER(hook))) {
 1811                         TRAP_ERROR();
 1812                         NG_NODE_UNREF(node);
 1813                         TOPOLOGY_WUNLOCK();
 1814                         return (ENOENT);
 1815                 }
 1816 
 1817                 /*
 1818                  * Hop on over to the next node
 1819                  * XXX
 1820                  * Big race conditions here as hooks and nodes go away
 1821                  * *** Idea.. store an ng_ID_t in each hook and use that
 1822                  * instead of the direct hook in this crawl?
 1823                  */
 1824                 oldnode = node;
 1825                 if ((node = NG_PEER_NODE(hook)))
 1826                         NG_NODE_REF(node);      /* XXX RACE */
 1827                 NG_NODE_UNREF(oldnode); /* XXX another race */
 1828                 if (NG_NODE_NOT_VALID(node)) {
 1829                         NG_NODE_UNREF(node);    /* XXX more races */
 1830                         TOPOLOGY_WUNLOCK();
 1831                         TRAP_ERROR();
 1832                         return (ENXIO);
 1833                 }
 1834 
 1835                 if (*path == '\0') {
 1836                         if (lasthook != NULL) {
 1837                                 if (hook != NULL) {
 1838                                         *lasthook = NG_HOOK_PEER(hook);
 1839                                         NG_HOOK_REF(*lasthook);
 1840                                 } else
 1841                                         *lasthook = NULL;
 1842                         }
 1843                         TOPOLOGY_WUNLOCK();
 1844                         *destp = node;
 1845                         return (0);
 1846                 }
 1847                 TOPOLOGY_WUNLOCK();
 1848         }
 1849 }
 1850 
 1851 /***************************************************************\
 1852 * Input queue handling.
 1853 * All activities are submitted to the node via the input queue
 1854 * which implements a multiple-reader/single-writer gate.
 1855 * Items which cannot be handled immediately are queued.
 1856 *
 1857 * read-write queue locking inline functions                     *
 1858 \***************************************************************/
 1859 
 1860 static __inline void    ng_queue_rw(node_p node, item_p  item, int rw);
 1861 static __inline item_p  ng_dequeue(node_p node, int *rw);
 1862 static __inline item_p  ng_acquire_read(node_p node, item_p  item);
 1863 static __inline item_p  ng_acquire_write(node_p node, item_p  item);
 1864 static __inline void    ng_leave_read(node_p node);
 1865 static __inline void    ng_leave_write(node_p node);
 1866 
 1867 /*
 1868  * Definition of the bits fields in the ng_queue flag word.
 1869  * Defined here rather than in netgraph.h because no-one should fiddle
 1870  * with them.
 1871  *
 1872  * The ordering here may be important! don't shuffle these.
 1873  */
 1874 /*-
 1875  Safety Barrier--------+ (adjustable to suit taste) (not used yet)
 1876                        |
 1877                        V
 1878 +-------+-------+-------+-------+-------+-------+-------+-------+
 1879   | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
 1880   | |A|c|t|i|v|e| |R|e|a|d|e|r| |C|o|u|n|t| | | | | | | | | |P|A|
 1881   | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |O|W|
 1882 +-------+-------+-------+-------+-------+-------+-------+-------+
 1883   \___________________________ ____________________________/ | |
 1884                             V                                | |
 1885                   [active reader count]                      | |
 1886                                                              | |
 1887             Operation Pending -------------------------------+ |
 1888                                                                |
 1889           Active Writer ---------------------------------------+
 1890 
 1891 Node queue has such semantics:
 1892 - All flags modifications are atomic.
 1893 - Reader count can be incremented only if there is no writer or pending flags.
 1894   As soon as this can't be done with single operation, it is implemented with
 1895   spin loop and atomic_cmpset().
 1896 - Writer flag can be set only if there is no any bits set.
 1897   It is implemented with atomic_cmpset().
 1898 - Pending flag can be set any time, but to avoid collision on queue processing
 1899   all queue fields are protected by the mutex.
 1900 - Queue processing thread reads queue holding the mutex, but releases it while
 1901   processing. When queue is empty pending flag is removed.
 1902 */
 1903 
 1904 #define WRITER_ACTIVE   0x00000001
 1905 #define OP_PENDING      0x00000002
 1906 #define READER_INCREMENT 0x00000004
 1907 #define READER_MASK     0xfffffffc      /* Not valid if WRITER_ACTIVE is set */
 1908 #define SAFETY_BARRIER  0x00100000      /* 128K items queued should be enough */
 1909 
 1910 /* Defines of more elaborate states on the queue */
 1911 /* Mask of bits a new read cares about */
 1912 #define NGQ_RMASK       (WRITER_ACTIVE|OP_PENDING)
 1913 
 1914 /* Mask of bits a new write cares about */
 1915 #define NGQ_WMASK       (NGQ_RMASK|READER_MASK)
 1916 
 1917 /* Test to decide if there is something on the queue. */
 1918 #define QUEUE_ACTIVE(QP) ((QP)->q_flags & OP_PENDING)
 1919 
 1920 /* How to decide what the next queued item is. */
 1921 #define HEAD_IS_READER(QP)  NGI_QUEUED_READER(STAILQ_FIRST(&(QP)->queue))
 1922 #define HEAD_IS_WRITER(QP)  NGI_QUEUED_WRITER(STAILQ_FIRST(&(QP)->queue)) /* notused */
 1923 
 1924 /* Read the status to decide if the next item on the queue can now run. */
 1925 #define QUEUED_READER_CAN_PROCEED(QP)                   \
 1926                 (((QP)->q_flags & (NGQ_RMASK & ~OP_PENDING)) == 0)
 1927 #define QUEUED_WRITER_CAN_PROCEED(QP)                   \
 1928                 (((QP)->q_flags & (NGQ_WMASK & ~OP_PENDING)) == 0)
 1929 
 1930 /* Is there a chance of getting ANY work off the queue? */
 1931 #define NEXT_QUEUED_ITEM_CAN_PROCEED(QP)                                \
 1932         ((HEAD_IS_READER(QP)) ? QUEUED_READER_CAN_PROCEED(QP) :         \
 1933                                 QUEUED_WRITER_CAN_PROCEED(QP))
 1934 
 1935 #define NGQRW_R 0
 1936 #define NGQRW_W 1
 1937 
 1938 #define NGQ2_WORKQ      0x00000001
 1939 
 1940 /*
 1941  * Taking into account the current state of the queue and node, possibly take
 1942  * the next entry off the queue and return it. Return NULL if there was
 1943  * nothing we could return, either because there really was nothing there, or
 1944  * because the node was in a state where it cannot yet process the next item
 1945  * on the queue.
 1946  */
 1947 static __inline item_p
 1948 ng_dequeue(node_p node, int *rw)
 1949 {
 1950         item_p item;
 1951         struct ng_queue *ngq = &node->nd_input_queue;
 1952 
 1953         /* This MUST be called with the mutex held. */
 1954         mtx_assert(&ngq->q_mtx, MA_OWNED);
 1955 
 1956         /* If there is nothing queued, then just return. */
 1957         if (!QUEUE_ACTIVE(ngq)) {
 1958                 CTR4(KTR_NET, "%20s: node [%x] (%p) queue empty; "
 1959                     "queue flags 0x%lx", __func__,
 1960                     node->nd_ID, node, ngq->q_flags);
 1961                 return (NULL);
 1962         }
 1963 
 1964         /*
 1965          * From here, we can assume there is a head item.
 1966          * We need to find out what it is and if it can be dequeued, given
 1967          * the current state of the node.
 1968          */
 1969         if (HEAD_IS_READER(ngq)) {
 1970                 while (1) {
 1971                         long t = ngq->q_flags;
 1972                         if (t & WRITER_ACTIVE) {
 1973                                 /* There is writer, reader can't proceed. */
 1974                                 CTR4(KTR_NET, "%20s: node [%x] (%p) queued "
 1975                                     "reader can't proceed; queue flags 0x%lx",
 1976                                     __func__, node->nd_ID, node, t);
 1977                                 return (NULL);
 1978                         }
 1979                         if (atomic_cmpset_acq_int(&ngq->q_flags, t,
 1980                             t + READER_INCREMENT))
 1981                                 break;
 1982                         cpu_spinwait();
 1983                 }
 1984                 /* We have got reader lock for the node. */
 1985                 *rw = NGQRW_R;
 1986         } else if (atomic_cmpset_acq_int(&ngq->q_flags, OP_PENDING,
 1987             OP_PENDING + WRITER_ACTIVE)) {
 1988                 /* We have got writer lock for the node. */
 1989                 *rw = NGQRW_W;
 1990         } else {
 1991                 /* There is somebody other, writer can't proceed. */
 1992                 CTR4(KTR_NET, "%20s: node [%x] (%p) queued writer can't "
 1993                     "proceed; queue flags 0x%lx", __func__, node->nd_ID, node,
 1994                     ngq->q_flags);
 1995                 return (NULL);
 1996         }
 1997 
 1998         /*
 1999          * Now we dequeue the request (whatever it may be) and correct the
 2000          * pending flags and the next and last pointers.
 2001          */
 2002         item = STAILQ_FIRST(&ngq->queue);
 2003         STAILQ_REMOVE_HEAD(&ngq->queue, el_next);
 2004         if (STAILQ_EMPTY(&ngq->queue))
 2005                 atomic_clear_int(&ngq->q_flags, OP_PENDING);
 2006         CTR6(KTR_NET, "%20s: node [%x] (%p) returning item %p as %s; queue "
 2007             "flags 0x%lx", __func__, node->nd_ID, node, item, *rw ? "WRITER" :
 2008             "READER", ngq->q_flags);
 2009         return (item);
 2010 }
 2011 
 2012 /*
 2013  * Queue a packet to be picked up later by someone else.
 2014  * If the queue could be run now, add node to the queue handler's worklist.
 2015  */
 2016 static __inline void
 2017 ng_queue_rw(node_p node, item_p  item, int rw)
 2018 {
 2019         struct ng_queue *ngq = &node->nd_input_queue;
 2020         if (rw == NGQRW_W)
 2021                 NGI_SET_WRITER(item);
 2022         else
 2023                 NGI_SET_READER(item);
 2024         item->depth = 1;
 2025 
 2026         NG_QUEUE_LOCK(ngq);
 2027         /* Set OP_PENDING flag and enqueue the item. */
 2028         atomic_set_int(&ngq->q_flags, OP_PENDING);
 2029         STAILQ_INSERT_TAIL(&ngq->queue, item, el_next);
 2030 
 2031         CTR5(KTR_NET, "%20s: node [%x] (%p) queued item %p as %s", __func__,
 2032             node->nd_ID, node, item, rw ? "WRITER" : "READER" );
 2033 
 2034         /*
 2035          * We can take the worklist lock with the node locked
 2036          * BUT NOT THE REVERSE!
 2037          */
 2038         if (NEXT_QUEUED_ITEM_CAN_PROCEED(ngq))
 2039                 ng_worklist_add(node);
 2040         NG_QUEUE_UNLOCK(ngq);
 2041 }
 2042 
 2043 /* Acquire reader lock on node. If node is busy, queue the packet. */
 2044 static __inline item_p
 2045 ng_acquire_read(node_p node, item_p item)
 2046 {
 2047         KASSERT(node != &ng_deadnode,
 2048             ("%s: working on deadnode", __func__));
 2049 
 2050         /* Reader needs node without writer and pending items. */
 2051         for (;;) {
 2052                 long t = node->nd_input_queue.q_flags;
 2053                 if (t & NGQ_RMASK)
 2054                         break; /* Node is not ready for reader. */
 2055                 if (atomic_cmpset_acq_int(&node->nd_input_queue.q_flags, t,
 2056                     t + READER_INCREMENT)) {
 2057                         /* Successfully grabbed node */
 2058                         CTR4(KTR_NET, "%20s: node [%x] (%p) acquired item %p",
 2059                             __func__, node->nd_ID, node, item);
 2060                         return (item);
 2061                 }
 2062                 cpu_spinwait();
 2063         }
 2064 
 2065         /* Queue the request for later. */
 2066         ng_queue_rw(node, item, NGQRW_R);
 2067 
 2068         return (NULL);
 2069 }
 2070 
 2071 /* Acquire writer lock on node. If node is busy, queue the packet. */
 2072 static __inline item_p
 2073 ng_acquire_write(node_p node, item_p item)
 2074 {
 2075         KASSERT(node != &ng_deadnode,
 2076             ("%s: working on deadnode", __func__));
 2077 
 2078         /* Writer needs completely idle node. */
 2079         if (atomic_cmpset_acq_int(&node->nd_input_queue.q_flags, 0,
 2080             WRITER_ACTIVE)) {
 2081                 /* Successfully grabbed node */
 2082                 CTR4(KTR_NET, "%20s: node [%x] (%p) acquired item %p",
 2083                     __func__, node->nd_ID, node, item);
 2084                 return (item);
 2085         }
 2086 
 2087         /* Queue the request for later. */
 2088         ng_queue_rw(node, item, NGQRW_W);
 2089 
 2090         return (NULL);
 2091 }
 2092 
 2093 #if 0
 2094 static __inline item_p
 2095 ng_upgrade_write(node_p node, item_p item)
 2096 {
 2097         struct ng_queue *ngq = &node->nd_input_queue;
 2098         KASSERT(node != &ng_deadnode,
 2099             ("%s: working on deadnode", __func__));
 2100 
 2101         NGI_SET_WRITER(item);
 2102 
 2103         NG_QUEUE_LOCK(ngq);
 2104 
 2105         /*
 2106          * There will never be no readers as we are there ourselves.
 2107          * Set the WRITER_ACTIVE flags ASAP to block out fast track readers.
 2108          * The caller we are running from will call ng_leave_read()
 2109          * soon, so we must account for that. We must leave again with the
 2110          * READER lock. If we find other readers, then
 2111          * queue the request for later. However "later" may be rignt now
 2112          * if there are no readers. We don't really care if there are queued
 2113          * items as we will bypass them anyhow.
 2114          */
 2115         atomic_add_int(&ngq->q_flags, WRITER_ACTIVE - READER_INCREMENT);
 2116         if ((ngq->q_flags & (NGQ_WMASK & ~OP_PENDING)) == WRITER_ACTIVE) {
 2117                 NG_QUEUE_UNLOCK(ngq);
 2118                 
 2119                 /* It's just us, act on the item. */
 2120                 /* will NOT drop writer lock when done */
 2121                 ng_apply_item(node, item, 0);
 2122 
 2123                 /*
 2124                  * Having acted on the item, atomically
 2125                  * downgrade back to READER and finish up.
 2126                  */
 2127                 atomic_add_int(&ngq->q_flags, READER_INCREMENT - WRITER_ACTIVE);
 2128 
 2129                 /* Our caller will call ng_leave_read() */
 2130                 return;
 2131         }
 2132         /*
 2133          * It's not just us active, so queue us AT THE HEAD.
 2134          * "Why?" I hear you ask.
 2135          * Put us at the head of the queue as we've already been
 2136          * through it once. If there is nothing else waiting,
 2137          * set the correct flags.
 2138          */
 2139         if (STAILQ_EMPTY(&ngq->queue)) {
 2140                 /* We've gone from, 0 to 1 item in the queue */
 2141                 atomic_set_int(&ngq->q_flags, OP_PENDING);
 2142 
 2143                 CTR3(KTR_NET, "%20s: node [%x] (%p) set OP_PENDING", __func__,
 2144                     node->nd_ID, node);
 2145         };
 2146         STAILQ_INSERT_HEAD(&ngq->queue, item, el_next);
 2147         CTR4(KTR_NET, "%20s: node [%x] (%p) requeued item %p as WRITER",
 2148             __func__, node->nd_ID, node, item );
 2149 
 2150         /* Reverse what we did above. That downgrades us back to reader */
 2151         atomic_add_int(&ngq->q_flags, READER_INCREMENT - WRITER_ACTIVE);
 2152         if (QUEUE_ACTIVE(ngq) && NEXT_QUEUED_ITEM_CAN_PROCEED(ngq))
 2153                 ng_worklist_add(node);
 2154         NG_QUEUE_UNLOCK(ngq);
 2155 
 2156         return;
 2157 }
 2158 #endif
 2159 
 2160 /* Release reader lock. */
 2161 static __inline void
 2162 ng_leave_read(node_p node)
 2163 {
 2164         atomic_subtract_rel_int(&node->nd_input_queue.q_flags, READER_INCREMENT);
 2165 }
 2166 
 2167 /* Release writer lock. */
 2168 static __inline void
 2169 ng_leave_write(node_p node)
 2170 {
 2171         atomic_clear_rel_int(&node->nd_input_queue.q_flags, WRITER_ACTIVE);
 2172 }
 2173 
 2174 /* Purge node queue. Called on node shutdown. */
 2175 static void
 2176 ng_flush_input_queue(node_p node)
 2177 {
 2178         struct ng_queue *ngq = &node->nd_input_queue;
 2179         item_p item;
 2180 
 2181         NG_QUEUE_LOCK(ngq);
 2182         while ((item = STAILQ_FIRST(&ngq->queue)) != NULL) {
 2183                 STAILQ_REMOVE_HEAD(&ngq->queue, el_next);
 2184                 if (STAILQ_EMPTY(&ngq->queue))
 2185                         atomic_clear_int(&ngq->q_flags, OP_PENDING);
 2186                 NG_QUEUE_UNLOCK(ngq);
 2187 
 2188                 /* If the item is supplying a callback, call it with an error */
 2189                 if (item->apply != NULL) {
 2190                         if (item->depth == 1)
 2191                                 item->apply->error = ENOENT;
 2192                         if (refcount_release(&item->apply->refs)) {
 2193                                 (*item->apply->apply)(item->apply->context,
 2194                                     item->apply->error);
 2195                         }
 2196                 }
 2197                 NG_FREE_ITEM(item);
 2198                 NG_QUEUE_LOCK(ngq);
 2199         }
 2200         NG_QUEUE_UNLOCK(ngq);
 2201 }
 2202 
 2203 /***********************************************************************
 2204 * Externally visible method for sending or queueing messages or data.
 2205 ***********************************************************************/
 2206 
 2207 /*
 2208  * The module code should have filled out the item correctly by this stage:
 2209  * Common:
 2210  *    reference to destination node.
 2211  *    Reference to destination rcv hook if relevant.
 2212  *    apply pointer must be or NULL or reference valid struct ng_apply_info.
 2213  * Data:
 2214  *    pointer to mbuf
 2215  * Control_Message:
 2216  *    pointer to msg.
 2217  *    ID of original sender node. (return address)
 2218  * Function:
 2219  *    Function pointer
 2220  *    void * argument
 2221  *    integer argument
 2222  *
 2223  * The nodes have several routines and macros to help with this task:
 2224  */
 2225 
 2226 int
 2227 ng_snd_item(item_p item, int flags)
 2228 {
 2229         hook_p hook;
 2230         node_p node;
 2231         int queue, rw;
 2232         struct ng_queue *ngq;
 2233         int error = 0;
 2234 
 2235         /* We are sending item, so it must be present! */
 2236         KASSERT(item != NULL, ("ng_snd_item: item is NULL"));
 2237 
 2238 #ifdef  NETGRAPH_DEBUG
 2239         _ngi_check(item, __FILE__, __LINE__);
 2240 #endif
 2241 
 2242         /* Item was sent once more, postpone apply() call. */
 2243         if (item->apply)
 2244                 refcount_acquire(&item->apply->refs);
 2245 
 2246         node = NGI_NODE(item);
 2247         /* Node is never optional. */
 2248         KASSERT(node != NULL, ("ng_snd_item: node is NULL"));
 2249 
 2250         hook = NGI_HOOK(item);
 2251         /* Valid hook and mbuf are mandatory for data. */
 2252         if ((item->el_flags & NGQF_TYPE) == NGQF_DATA) {
 2253                 KASSERT(hook != NULL, ("ng_snd_item: hook for data is NULL"));
 2254                 if (NGI_M(item) == NULL)
 2255                         ERROUT(EINVAL);
 2256                 CHECK_DATA_MBUF(NGI_M(item));
 2257         }
 2258 
 2259         /*
 2260          * If the item or the node specifies single threading, force
 2261          * writer semantics. Similarly, the node may say one hook always
 2262          * produces writers. These are overrides.
 2263          */
 2264         if (((item->el_flags & NGQF_RW) == NGQF_WRITER) ||
 2265             (node->nd_flags & NGF_FORCE_WRITER) ||
 2266             (hook && (hook->hk_flags & HK_FORCE_WRITER))) {
 2267                 rw = NGQRW_W;
 2268         } else {
 2269                 rw = NGQRW_R;
 2270         }
 2271 
 2272         /*
 2273          * If sender or receiver requests queued delivery, or call graph
 2274          * loops back from outbound to inbound path, or stack usage
 2275          * level is dangerous - enqueue message.
 2276          */
 2277         if ((flags & NG_QUEUE) || (hook && (hook->hk_flags & HK_QUEUE))) {
 2278                 queue = 1;
 2279         } else if (hook && (hook->hk_flags & HK_TO_INBOUND) &&
 2280             curthread->td_ng_outbound) {
 2281                 queue = 1;
 2282         } else {
 2283                 queue = 0;
 2284 #ifdef GET_STACK_USAGE
 2285                 /*
 2286                  * Most of netgraph nodes have small stack consumption and
 2287                  * for them 25% of free stack space is more than enough.
 2288                  * Nodes/hooks with higher stack usage should be marked as
 2289                  * HI_STACK. For them 50% of stack will be guaranteed then.
 2290                  * XXX: Values 25% and 50% are completely empirical.
 2291                  */
 2292                 size_t  st, su, sl;
 2293                 GET_STACK_USAGE(st, su);
 2294                 sl = st - su;
 2295                 if ((sl * 4 < st) || ((sl * 2 < st) &&
 2296                     ((node->nd_flags & NGF_HI_STACK) || (hook &&
 2297                     (hook->hk_flags & HK_HI_STACK)))))
 2298                         queue = 1;
 2299 #endif
 2300         }
 2301 
 2302         if (queue) {
 2303                 /* Put it on the queue for that node*/
 2304                 ng_queue_rw(node, item, rw);
 2305                 return ((flags & NG_PROGRESS) ? EINPROGRESS : 0);
 2306         }
 2307 
 2308         /*
 2309          * We already decided how we will be queueud or treated.
 2310          * Try get the appropriate operating permission.
 2311          */
 2312         if (rw == NGQRW_R)
 2313                 item = ng_acquire_read(node, item);
 2314         else
 2315                 item = ng_acquire_write(node, item);
 2316 
 2317         /* Item was queued while trying to get permission. */
 2318         if (item == NULL)
 2319                 return ((flags & NG_PROGRESS) ? EINPROGRESS : 0);
 2320 
 2321         NGI_GET_NODE(item, node); /* zaps stored node */
 2322 
 2323         item->depth++;
 2324         error = ng_apply_item(node, item, rw); /* drops r/w lock when done */
 2325 
 2326         /* If something is waiting on queue and ready, schedule it. */
 2327         ngq = &node->nd_input_queue;
 2328         if (QUEUE_ACTIVE(ngq)) {
 2329                 NG_QUEUE_LOCK(ngq);
 2330                 if (QUEUE_ACTIVE(ngq) && NEXT_QUEUED_ITEM_CAN_PROCEED(ngq))
 2331                         ng_worklist_add(node);
 2332                 NG_QUEUE_UNLOCK(ngq);
 2333         }
 2334 
 2335         /*
 2336          * Node may go away as soon as we remove the reference.
 2337          * Whatever we do, DO NOT access the node again!
 2338          */
 2339         NG_NODE_UNREF(node);
 2340 
 2341         return (error);
 2342 
 2343 done:
 2344         /* If was not sent, apply callback here. */
 2345         if (item->apply != NULL) {
 2346                 if (item->depth == 0 && error != 0)
 2347                         item->apply->error = error;
 2348                 if (refcount_release(&item->apply->refs)) {
 2349                         (*item->apply->apply)(item->apply->context,
 2350                             item->apply->error);
 2351                 }
 2352         }
 2353 
 2354         NG_FREE_ITEM(item);
 2355         return (error);
 2356 }
 2357 
 2358 /*
 2359  * We have an item that was possibly queued somewhere.
 2360  * It should contain all the information needed
 2361  * to run it on the appropriate node/hook.
 2362  * If there is apply pointer and we own the last reference, call apply().
 2363  */
 2364 static int
 2365 ng_apply_item(node_p node, item_p item, int rw)
 2366 {
 2367         hook_p  hook;
 2368         ng_rcvdata_t *rcvdata;
 2369         ng_rcvmsg_t *rcvmsg;
 2370         struct ng_apply_info *apply;
 2371         int     error = 0, depth;
 2372 
 2373         /* Node and item are never optional. */
 2374         KASSERT(node != NULL, ("ng_apply_item: node is NULL"));
 2375         KASSERT(item != NULL, ("ng_apply_item: item is NULL"));
 2376 
 2377         NGI_GET_HOOK(item, hook); /* clears stored hook */
 2378 #ifdef  NETGRAPH_DEBUG
 2379         _ngi_check(item, __FILE__, __LINE__);
 2380 #endif
 2381 
 2382         apply = item->apply;
 2383         depth = item->depth;
 2384 
 2385         switch (item->el_flags & NGQF_TYPE) {
 2386         case NGQF_DATA:
 2387                 /*
 2388                  * Check things are still ok as when we were queued.
 2389                  */
 2390                 KASSERT(hook != NULL, ("ng_apply_item: hook for data is NULL"));
 2391                 if (NG_HOOK_NOT_VALID(hook) ||
 2392                     NG_NODE_NOT_VALID(node)) {
 2393                         error = EIO;
 2394                         NG_FREE_ITEM(item);
 2395                         break;
 2396                 }
 2397                 /*
 2398                  * If no receive method, just silently drop it.
 2399                  * Give preference to the hook over-ride method.
 2400                  */
 2401                 if ((!(rcvdata = hook->hk_rcvdata)) &&
 2402                     (!(rcvdata = NG_HOOK_NODE(hook)->nd_type->rcvdata))) {
 2403                         error = 0;
 2404                         NG_FREE_ITEM(item);
 2405                         break;
 2406                 }
 2407                 error = (*rcvdata)(hook, item);
 2408                 break;
 2409         case NGQF_MESG:
 2410                 if (hook && NG_HOOK_NOT_VALID(hook)) {
 2411                         /*
 2412                          * The hook has been zapped then we can't use it.
 2413                          * Immediately drop its reference.
 2414                          * The message may not need it.
 2415                          */
 2416                         NG_HOOK_UNREF(hook);
 2417                         hook = NULL;
 2418                 }
 2419                 /*
 2420                  * Similarly, if the node is a zombie there is
 2421                  * nothing we can do with it, drop everything.
 2422                  */
 2423                 if (NG_NODE_NOT_VALID(node)) {
 2424                         TRAP_ERROR();
 2425                         error = EINVAL;
 2426                         NG_FREE_ITEM(item);
 2427                         break;
 2428                 }
 2429                 /*
 2430                  * Call the appropriate message handler for the object.
 2431                  * It is up to the message handler to free the message.
 2432                  * If it's a generic message, handle it generically,
 2433                  * otherwise call the type's message handler (if it exists).
 2434                  * XXX (race). Remember that a queued message may
 2435                  * reference a node or hook that has just been
 2436                  * invalidated. It will exist as the queue code
 2437                  * is holding a reference, but..
 2438                  */
 2439                 if ((NGI_MSG(item)->header.typecookie == NGM_GENERIC_COOKIE) &&
 2440                     ((NGI_MSG(item)->header.flags & NGF_RESP) == 0)) {
 2441                         error = ng_generic_msg(node, item, hook);
 2442                         break;
 2443                 }
 2444                 if (((!hook) || (!(rcvmsg = hook->hk_rcvmsg))) &&
 2445                     (!(rcvmsg = node->nd_type->rcvmsg))) {
 2446                         TRAP_ERROR();
 2447                         error = 0;
 2448                         NG_FREE_ITEM(item);
 2449                         break;
 2450                 }
 2451                 error = (*rcvmsg)(node, item, hook);
 2452                 break;
 2453         case NGQF_FN:
 2454         case NGQF_FN2:
 2455                 /*
 2456                  * In the case of the shutdown message we allow it to hit
 2457                  * even if the node is invalid.
 2458                  */
 2459                 if (NG_NODE_NOT_VALID(node) &&
 2460                     NGI_FN(item) != &ng_rmnode) {
 2461                         TRAP_ERROR();
 2462                         error = EINVAL;
 2463                         NG_FREE_ITEM(item);
 2464                         break;
 2465                 }
 2466                 /* Same is about some internal functions and invalid hook. */
 2467                 if (hook && NG_HOOK_NOT_VALID(hook) &&
 2468                     NGI_FN2(item) != &ng_con_part2 &&
 2469                     NGI_FN2(item) != &ng_con_part3 &&
 2470                     NGI_FN(item) != &ng_rmhook_part2) {
 2471                         TRAP_ERROR();
 2472                         error = EINVAL;
 2473                         NG_FREE_ITEM(item);
 2474                         break;
 2475                 }
 2476                 
 2477                 if ((item->el_flags & NGQF_TYPE) == NGQF_FN) {
 2478                         (*NGI_FN(item))(node, hook, NGI_ARG1(item),
 2479                             NGI_ARG2(item));
 2480                         NG_FREE_ITEM(item);
 2481                 } else  /* it is NGQF_FN2 */
 2482                         error = (*NGI_FN2(item))(node, item, hook);
 2483                 break;
 2484         }
 2485         /*
 2486          * We held references on some of the resources
 2487          * that we took from the item. Now that we have
 2488          * finished doing everything, drop those references.
 2489          */
 2490         if (hook)
 2491                 NG_HOOK_UNREF(hook);
 2492 
 2493         if (rw == NGQRW_R)
 2494                 ng_leave_read(node);
 2495         else
 2496                 ng_leave_write(node);
 2497 
 2498         /* Apply callback. */
 2499         if (apply != NULL) {
 2500                 if (depth == 1 && error != 0)
 2501                         apply->error = error;
 2502                 if (refcount_release(&apply->refs))
 2503                         (*apply->apply)(apply->context, apply->error);
 2504         }
 2505 
 2506         return (error);
 2507 }
 2508 
 2509 /***********************************************************************
 2510  * Implement the 'generic' control messages
 2511  ***********************************************************************/
 2512 static int
 2513 ng_generic_msg(node_p here, item_p item, hook_p lasthook)
 2514 {
 2515         int error = 0;
 2516         struct ng_mesg *msg;
 2517         struct ng_mesg *resp = NULL;
 2518 
 2519         NGI_GET_MSG(item, msg);
 2520         if (msg->header.typecookie != NGM_GENERIC_COOKIE) {
 2521                 TRAP_ERROR();
 2522                 error = EINVAL;
 2523                 goto out;
 2524         }
 2525         switch (msg->header.cmd) {
 2526         case NGM_SHUTDOWN:
 2527                 ng_rmnode(here, NULL, NULL, 0);
 2528                 break;
 2529         case NGM_MKPEER:
 2530             {
 2531                 struct ngm_mkpeer *const mkp = (struct ngm_mkpeer *) msg->data;
 2532 
 2533                 if (msg->header.arglen != sizeof(*mkp)) {
 2534                         TRAP_ERROR();
 2535                         error = EINVAL;
 2536                         break;
 2537                 }
 2538                 mkp->type[sizeof(mkp->type) - 1] = '\0';
 2539                 mkp->ourhook[sizeof(mkp->ourhook) - 1] = '\0';
 2540                 mkp->peerhook[sizeof(mkp->peerhook) - 1] = '\0';
 2541                 error = ng_mkpeer(here, mkp->ourhook, mkp->peerhook, mkp->type);
 2542                 break;
 2543             }
 2544         case NGM_CONNECT:
 2545             {
 2546                 struct ngm_connect *const con =
 2547                         (struct ngm_connect *) msg->data;
 2548                 node_p node2;
 2549 
 2550                 if (msg->header.arglen != sizeof(*con)) {
 2551                         TRAP_ERROR();
 2552                         error = EINVAL;
 2553                         break;
 2554                 }
 2555                 con->path[sizeof(con->path) - 1] = '\0';
 2556                 con->ourhook[sizeof(con->ourhook) - 1] = '\0';
 2557                 con->peerhook[sizeof(con->peerhook) - 1] = '\0';
 2558                 /* Don't forget we get a reference.. */
 2559                 error = ng_path2noderef(here, con->path, &node2, NULL);
 2560                 if (error)
 2561                         break;
 2562                 error = ng_con_nodes(item, here, con->ourhook,
 2563                     node2, con->peerhook);
 2564                 NG_NODE_UNREF(node2);
 2565                 break;
 2566             }
 2567         case NGM_NAME:
 2568             {
 2569                 struct ngm_name *const nam = (struct ngm_name *) msg->data;
 2570 
 2571                 if (msg->header.arglen != sizeof(*nam)) {
 2572                         TRAP_ERROR();
 2573                         error = EINVAL;
 2574                         break;
 2575                 }
 2576                 nam->name[sizeof(nam->name) - 1] = '\0';
 2577                 error = ng_name_node(here, nam->name);
 2578                 break;
 2579             }
 2580         case NGM_RMHOOK:
 2581             {
 2582                 struct ngm_rmhook *const rmh = (struct ngm_rmhook *) msg->data;
 2583                 hook_p hook;
 2584 
 2585                 if (msg->header.arglen != sizeof(*rmh)) {
 2586                         TRAP_ERROR();
 2587                         error = EINVAL;
 2588                         break;
 2589                 }
 2590                 rmh->ourhook[sizeof(rmh->ourhook) - 1] = '\0';
 2591                 if ((hook = ng_findhook(here, rmh->ourhook)) != NULL)
 2592                         ng_destroy_hook(hook);
 2593                 break;
 2594             }
 2595         case NGM_NODEINFO:
 2596             {
 2597                 struct nodeinfo *ni;
 2598 
 2599                 NG_MKRESPONSE(resp, msg, sizeof(*ni), M_NOWAIT);
 2600                 if (resp == NULL) {
 2601                         error = ENOMEM;
 2602                         break;
 2603                 }
 2604 
 2605                 /* Fill in node info */
 2606                 ni = (struct nodeinfo *) resp->data;
 2607                 if (NG_NODE_HAS_NAME(here))
 2608                         strcpy(ni->name, NG_NODE_NAME(here));
 2609                 strcpy(ni->type, here->nd_type->name);
 2610                 ni->id = ng_node2ID(here);
 2611                 ni->hooks = here->nd_numhooks;
 2612                 break;
 2613             }
 2614         case NGM_LISTHOOKS:
 2615             {
 2616                 const int nhooks = here->nd_numhooks;
 2617                 struct hooklist *hl;
 2618                 struct nodeinfo *ni;
 2619                 hook_p hook;
 2620 
 2621                 /* Get response struct */
 2622                 NG_MKRESPONSE(resp, msg, sizeof(*hl) +
 2623                     (nhooks * sizeof(struct linkinfo)), M_NOWAIT);
 2624                 if (resp == NULL) {
 2625                         error = ENOMEM;
 2626                         break;
 2627                 }
 2628                 hl = (struct hooklist *) resp->data;
 2629                 ni = &hl->nodeinfo;
 2630 
 2631                 /* Fill in node info */
 2632                 if (NG_NODE_HAS_NAME(here))
 2633                         strcpy(ni->name, NG_NODE_NAME(here));
 2634                 strcpy(ni->type, here->nd_type->name);
 2635                 ni->id = ng_node2ID(here);
 2636 
 2637                 /* Cycle through the linked list of hooks */
 2638                 ni->hooks = 0;
 2639                 LIST_FOREACH(hook, &here->nd_hooks, hk_hooks) {
 2640                         struct linkinfo *const link = &hl->link[ni->hooks];
 2641 
 2642                         if (ni->hooks >= nhooks) {
 2643                                 log(LOG_ERR, "%s: number of %s changed\n",
 2644                                     __func__, "hooks");
 2645                                 break;
 2646                         }
 2647                         if (NG_HOOK_NOT_VALID(hook))
 2648                                 continue;
 2649                         strcpy(link->ourhook, NG_HOOK_NAME(hook));
 2650                         strcpy(link->peerhook, NG_PEER_HOOK_NAME(hook));
 2651                         if (NG_PEER_NODE_NAME(hook)[0] != '\0')
 2652                                 strcpy(link->nodeinfo.name,
 2653                                     NG_PEER_NODE_NAME(hook));
 2654                         strcpy(link->nodeinfo.type,
 2655                            NG_PEER_NODE(hook)->nd_type->name);
 2656                         link->nodeinfo.id = ng_node2ID(NG_PEER_NODE(hook));
 2657                         link->nodeinfo.hooks = NG_PEER_NODE(hook)->nd_numhooks;
 2658                         ni->hooks++;
 2659                 }
 2660                 break;
 2661             }
 2662 
 2663         case NGM_LISTNODES:
 2664             {
 2665                 struct namelist *nl;
 2666                 node_p node;
 2667                 int i;
 2668 
 2669                 IDHASH_RLOCK();
 2670                 /* Get response struct. */
 2671                 NG_MKRESPONSE(resp, msg, sizeof(*nl) +
 2672                     (V_ng_nodes * sizeof(struct nodeinfo)), M_NOWAIT);
 2673                 if (resp == NULL) {
 2674                         IDHASH_RUNLOCK();
 2675                         error = ENOMEM;
 2676                         break;
 2677                 }
 2678                 nl = (struct namelist *) resp->data;
 2679 
 2680                 /* Cycle through the lists of nodes. */
 2681                 nl->numnames = 0;
 2682                 for (i = 0; i <= V_ng_ID_hmask; i++) {
 2683                         LIST_FOREACH(node, &V_ng_ID_hash[i], nd_idnodes) {
 2684                                 struct nodeinfo *const np =
 2685                                     &nl->nodeinfo[nl->numnames];
 2686 
 2687                                 if (NG_NODE_NOT_VALID(node))
 2688                                         continue;
 2689                                 if (NG_NODE_HAS_NAME(node))
 2690                                         strcpy(np->name, NG_NODE_NAME(node));
 2691                                 strcpy(np->type, node->nd_type->name);
 2692                                 np->id = ng_node2ID(node);
 2693                                 np->hooks = node->nd_numhooks;
 2694                                 KASSERT(nl->numnames < V_ng_nodes,
 2695                                     ("%s: no space", __func__));
 2696                                 nl->numnames++;
 2697                         }
 2698                 }
 2699                 IDHASH_RUNLOCK();
 2700                 break;
 2701             }
 2702         case NGM_LISTNAMES:
 2703             {
 2704                 struct namelist *nl;
 2705                 node_p node;
 2706                 int i;
 2707 
 2708                 NAMEHASH_RLOCK();
 2709                 /* Get response struct. */
 2710                 NG_MKRESPONSE(resp, msg, sizeof(*nl) +
 2711                     (V_ng_named_nodes * sizeof(struct nodeinfo)), M_NOWAIT);
 2712                 if (resp == NULL) {
 2713                         NAMEHASH_RUNLOCK();
 2714                         error = ENOMEM;
 2715                         break;
 2716                 }
 2717                 nl = (struct namelist *) resp->data;
 2718 
 2719                 /* Cycle through the lists of nodes. */
 2720                 nl->numnames = 0;
 2721                 for (i = 0; i <= V_ng_name_hmask; i++) {
 2722                         LIST_FOREACH(node, &V_ng_name_hash[i], nd_nodes) {
 2723                                 struct nodeinfo *const np =
 2724                                     &nl->nodeinfo[nl->numnames];
 2725 
 2726                                 if (NG_NODE_NOT_VALID(node))
 2727                                         continue;
 2728                                 strcpy(np->name, NG_NODE_NAME(node));
 2729                                 strcpy(np->type, node->nd_type->name);
 2730                                 np->id = ng_node2ID(node);
 2731                                 np->hooks = node->nd_numhooks;
 2732                                 KASSERT(nl->numnames < V_ng_named_nodes,
 2733                                     ("%s: no space", __func__));
 2734                                 nl->numnames++;
 2735                         }
 2736                 }
 2737                 NAMEHASH_RUNLOCK();
 2738                 break;
 2739             }
 2740 
 2741         case NGM_LISTTYPES:
 2742             {
 2743                 struct typelist *tl;
 2744                 struct ng_type *type;
 2745                 int num = 0;
 2746 
 2747                 TYPELIST_RLOCK();
 2748                 /* Count number of types */
 2749                 LIST_FOREACH(type, &ng_typelist, types)
 2750                         num++;
 2751 
 2752                 /* Get response struct */
 2753                 NG_MKRESPONSE(resp, msg, sizeof(*tl) +
 2754                     (num * sizeof(struct typeinfo)), M_NOWAIT);
 2755                 if (resp == NULL) {
 2756                         TYPELIST_RUNLOCK();
 2757                         error = ENOMEM;
 2758                         break;
 2759                 }
 2760                 tl = (struct typelist *) resp->data;
 2761 
 2762                 /* Cycle through the linked list of types */
 2763                 tl->numtypes = 0;
 2764                 LIST_FOREACH(type, &ng_typelist, types) {
 2765                         struct typeinfo *const tp = &tl->typeinfo[tl->numtypes];
 2766 
 2767                         strcpy(tp->type_name, type->name);
 2768                         tp->numnodes = type->refs - 1; /* don't count list */
 2769                         KASSERT(tl->numtypes < num, ("%s: no space", __func__));
 2770                         tl->numtypes++;
 2771                 }
 2772                 TYPELIST_RUNLOCK();
 2773                 break;
 2774             }
 2775 
 2776         case NGM_BINARY2ASCII:
 2777             {
 2778                 int bufSize = 1024;
 2779                 const struct ng_parse_type *argstype;
 2780                 const struct ng_cmdlist *c;
 2781                 struct ng_mesg *binary, *ascii;
 2782 
 2783                 /* Data area must contain a valid netgraph message */
 2784                 binary = (struct ng_mesg *)msg->data;
 2785                 if (msg->header.arglen < sizeof(struct ng_mesg) ||
 2786                     (msg->header.arglen - sizeof(struct ng_mesg) <
 2787                     binary->header.arglen)) {
 2788                         TRAP_ERROR();
 2789                         error = EINVAL;
 2790                         break;
 2791                 }
 2792 retry_b2a:
 2793                 /* Get a response message with lots of room */
 2794                 NG_MKRESPONSE(resp, msg, sizeof(*ascii) + bufSize, M_NOWAIT);
 2795                 if (resp == NULL) {
 2796                         error = ENOMEM;
 2797                         break;
 2798                 }
 2799                 ascii = (struct ng_mesg *)resp->data;
 2800 
 2801                 /* Copy binary message header to response message payload */
 2802                 bcopy(binary, ascii, sizeof(*binary));
 2803 
 2804                 /* Find command by matching typecookie and command number */
 2805                 for (c = here->nd_type->cmdlist; c != NULL && c->name != NULL;
 2806                     c++) {
 2807                         if (binary->header.typecookie == c->cookie &&
 2808                             binary->header.cmd == c->cmd)
 2809                                 break;
 2810                 }
 2811                 if (c == NULL || c->name == NULL) {
 2812                         for (c = ng_generic_cmds; c->name != NULL; c++) {
 2813                                 if (binary->header.typecookie == c->cookie &&
 2814                                     binary->header.cmd == c->cmd)
 2815                                         break;
 2816                         }
 2817                         if (c->name == NULL) {
 2818                                 NG_FREE_MSG(resp);
 2819                                 error = ENOSYS;
 2820                                 break;
 2821                         }
 2822                 }
 2823 
 2824                 /* Convert command name to ASCII */
 2825                 snprintf(ascii->header.cmdstr, sizeof(ascii->header.cmdstr),
 2826                     "%s", c->name);
 2827 
 2828                 /* Convert command arguments to ASCII */
 2829                 argstype = (binary->header.flags & NGF_RESP) ?
 2830                     c->respType : c->mesgType;
 2831                 if (argstype == NULL) {
 2832                         *ascii->data = '\0';
 2833                 } else {
 2834                         error = ng_unparse(argstype, (u_char *)binary->data,
 2835                             ascii->data, bufSize);
 2836                         if (error == ERANGE) {
 2837                                 NG_FREE_MSG(resp);
 2838                                 bufSize *= 2;
 2839                                 goto retry_b2a;
 2840                         } else if (error) {
 2841                                 NG_FREE_MSG(resp);
 2842                                 break;
 2843                         }
 2844                 }
 2845 
 2846                 /* Return the result as struct ng_mesg plus ASCII string */
 2847                 bufSize = strlen(ascii->data) + 1;
 2848                 ascii->header.arglen = bufSize;
 2849                 resp->header.arglen = sizeof(*ascii) + bufSize;
 2850                 break;
 2851             }
 2852 
 2853         case NGM_ASCII2BINARY:
 2854             {
 2855                 int bufSize = 20 * 1024;        /* XXX hard coded constant */
 2856                 const struct ng_cmdlist *c;
 2857                 const struct ng_parse_type *argstype;
 2858                 struct ng_mesg *ascii, *binary;
 2859                 int off = 0;
 2860 
 2861                 /* Data area must contain at least a struct ng_mesg + '\0' */
 2862                 ascii = (struct ng_mesg *)msg->data;
 2863                 if ((msg->header.arglen < sizeof(*ascii) + 1) ||
 2864                     (ascii->header.arglen < 1) ||
 2865                     (msg->header.arglen < sizeof(*ascii) +
 2866                     ascii->header.arglen)) {
 2867                         TRAP_ERROR();
 2868                         error = EINVAL;
 2869                         break;
 2870                 }
 2871                 ascii->data[ascii->header.arglen - 1] = '\0';
 2872 
 2873                 /* Get a response message with lots of room */
 2874                 NG_MKRESPONSE(resp, msg, sizeof(*binary) + bufSize, M_NOWAIT);
 2875                 if (resp == NULL) {
 2876                         error = ENOMEM;
 2877                         break;
 2878                 }
 2879                 binary = (struct ng_mesg *)resp->data;
 2880 
 2881                 /* Copy ASCII message header to response message payload */
 2882                 bcopy(ascii, binary, sizeof(*ascii));
 2883 
 2884                 /* Find command by matching ASCII command string */
 2885                 for (c = here->nd_type->cmdlist;
 2886                     c != NULL && c->name != NULL; c++) {
 2887                         if (strcmp(ascii->header.cmdstr, c->name) == 0)
 2888                                 break;
 2889                 }
 2890                 if (c == NULL || c->name == NULL) {
 2891                         for (c = ng_generic_cmds; c->name != NULL; c++) {
 2892                                 if (strcmp(ascii->header.cmdstr, c->name) == 0)
 2893                                         break;
 2894                         }
 2895                         if (c->name == NULL) {
 2896                                 NG_FREE_MSG(resp);
 2897                                 error = ENOSYS;
 2898                                 break;
 2899                         }
 2900                 }
 2901 
 2902                 /* Convert command name to binary */
 2903                 binary->header.cmd = c->cmd;
 2904                 binary->header.typecookie = c->cookie;
 2905 
 2906                 /* Convert command arguments to binary */
 2907                 argstype = (binary->header.flags & NGF_RESP) ?
 2908                     c->respType : c->mesgType;
 2909                 if (argstype == NULL) {
 2910                         bufSize = 0;
 2911                 } else {
 2912                         if ((error = ng_parse(argstype, ascii->data, &off,
 2913                             (u_char *)binary->data, &bufSize)) != 0) {
 2914                                 NG_FREE_MSG(resp);
 2915                                 break;
 2916                         }
 2917                 }
 2918 
 2919                 /* Return the result */
 2920                 binary->header.arglen = bufSize;
 2921                 resp->header.arglen = sizeof(*binary) + bufSize;
 2922                 break;
 2923             }
 2924 
 2925         case NGM_TEXT_CONFIG:
 2926         case NGM_TEXT_STATUS:
 2927                 /*
 2928                  * This one is tricky as it passes the command down to the
 2929                  * actual node, even though it is a generic type command.
 2930                  * This means we must assume that the item/msg is already freed
 2931                  * when control passes back to us.
 2932                  */
 2933                 if (here->nd_type->rcvmsg != NULL) {
 2934                         NGI_MSG(item) = msg; /* put it back as we found it */
 2935                         return((*here->nd_type->rcvmsg)(here, item, lasthook));
 2936                 }
 2937                 /* Fall through if rcvmsg not supported */
 2938         default:
 2939                 TRAP_ERROR();
 2940                 error = EINVAL;
 2941         }
 2942         /*
 2943          * Sometimes a generic message may be statically allocated
 2944          * to avoid problems with allocating when in tight memory situations.
 2945          * Don't free it if it is so.
 2946          * I break them apart here, because erros may cause a free if the item
 2947          * in which case we'd be doing it twice.
 2948          * they are kept together above, to simplify freeing.
 2949          */
 2950 out:
 2951         NG_RESPOND_MSG(error, here, item, resp);
 2952         NG_FREE_MSG(msg);
 2953         return (error);
 2954 }
 2955 
 2956 /************************************************************************
 2957                         Queue element get/free routines
 2958 ************************************************************************/
 2959 
 2960 uma_zone_t                      ng_qzone;
 2961 uma_zone_t                      ng_qdzone;
 2962 static int                      numthreads = 0; /* number of queue threads */
 2963 static int                      maxalloc = 4096;/* limit the damage of a leak */
 2964 static int                      maxdata = 4096; /* limit the damage of a DoS */
 2965 
 2966 SYSCTL_INT(_net_graph, OID_AUTO, threads, CTLFLAG_RDTUN, &numthreads,
 2967     0, "Number of queue processing threads");
 2968 SYSCTL_INT(_net_graph, OID_AUTO, maxalloc, CTLFLAG_RDTUN, &maxalloc,
 2969     0, "Maximum number of non-data queue items to allocate");
 2970 SYSCTL_INT(_net_graph, OID_AUTO, maxdata, CTLFLAG_RDTUN, &maxdata,
 2971     0, "Maximum number of data queue items to allocate");
 2972 
 2973 #ifdef  NETGRAPH_DEBUG
 2974 static TAILQ_HEAD(, ng_item) ng_itemlist = TAILQ_HEAD_INITIALIZER(ng_itemlist);
 2975 static int allocated;   /* number of items malloc'd */
 2976 #endif
 2977 
 2978 /*
 2979  * Get a queue entry.
 2980  * This is usually called when a packet first enters netgraph.
 2981  * By definition, this is usually from an interrupt, or from a user.
 2982  * Users are not so important, but try be quick for the times that it's
 2983  * an interrupt.
 2984  */
 2985 static __inline item_p
 2986 ng_alloc_item(int type, int flags)
 2987 {
 2988         item_p item;
 2989 
 2990         KASSERT(((type & ~NGQF_TYPE) == 0),
 2991             ("%s: incorrect item type: %d", __func__, type));
 2992 
 2993         item = uma_zalloc((type == NGQF_DATA) ? ng_qdzone : ng_qzone,
 2994             ((flags & NG_WAITOK) ? M_WAITOK : M_NOWAIT) | M_ZERO);
 2995 
 2996         if (item) {
 2997                 item->el_flags = type;
 2998 #ifdef  NETGRAPH_DEBUG
 2999                 mtx_lock(&ngq_mtx);
 3000                 TAILQ_INSERT_TAIL(&ng_itemlist, item, all);
 3001                 allocated++;
 3002                 mtx_unlock(&ngq_mtx);
 3003 #endif
 3004         }
 3005 
 3006         return (item);
 3007 }
 3008 
 3009 /*
 3010  * Release a queue entry
 3011  */
 3012 void
 3013 ng_free_item(item_p item)
 3014 {
 3015         /*
 3016          * The item may hold resources on it's own. We need to free
 3017          * these before we can free the item. What they are depends upon
 3018          * what kind of item it is. it is important that nodes zero
 3019          * out pointers to resources that they remove from the item
 3020          * or we release them again here.
 3021          */
 3022         switch (item->el_flags & NGQF_TYPE) {
 3023         case NGQF_DATA:
 3024                 /* If we have an mbuf still attached.. */
 3025                 NG_FREE_M(_NGI_M(item));
 3026                 break;
 3027         case NGQF_MESG:
 3028                 _NGI_RETADDR(item) = 0;
 3029                 NG_FREE_MSG(_NGI_MSG(item));
 3030                 break;
 3031         case NGQF_FN:
 3032         case NGQF_FN2:
 3033                 /* nothing to free really, */
 3034                 _NGI_FN(item) = NULL;
 3035                 _NGI_ARG1(item) = NULL;
 3036                 _NGI_ARG2(item) = 0;
 3037                 break;
 3038         }
 3039         /* If we still have a node or hook referenced... */
 3040         _NGI_CLR_NODE(item);
 3041         _NGI_CLR_HOOK(item);
 3042 
 3043 #ifdef  NETGRAPH_DEBUG
 3044         mtx_lock(&ngq_mtx);
 3045         TAILQ_REMOVE(&ng_itemlist, item, all);
 3046         allocated--;
 3047         mtx_unlock(&ngq_mtx);
 3048 #endif
 3049         uma_zfree(((item->el_flags & NGQF_TYPE) == NGQF_DATA) ?
 3050             ng_qdzone : ng_qzone, item);
 3051 }
 3052 
 3053 /*
 3054  * Change type of the queue entry.
 3055  * Possibly reallocates it from another UMA zone.
 3056  */
 3057 static __inline item_p
 3058 ng_realloc_item(item_p pitem, int type, int flags)
 3059 {
 3060         item_p item;
 3061         int from, to;
 3062 
 3063         KASSERT((pitem != NULL), ("%s: can't reallocate NULL", __func__));
 3064         KASSERT(((type & ~NGQF_TYPE) == 0),
 3065             ("%s: incorrect item type: %d", __func__, type));
 3066 
 3067         from = ((pitem->el_flags & NGQF_TYPE) == NGQF_DATA);
 3068         to = (type == NGQF_DATA);
 3069         if (from != to) {
 3070                 /* If reallocation is required do it and copy item. */
 3071                 if ((item = ng_alloc_item(type, flags)) == NULL) {
 3072                         ng_free_item(pitem);
 3073                         return (NULL);
 3074                 }
 3075                 *item = *pitem;
 3076                 ng_free_item(pitem);
 3077         } else
 3078                 item = pitem;
 3079         item->el_flags = (item->el_flags & ~NGQF_TYPE) | type;
 3080 
 3081         return (item);
 3082 }
 3083 
 3084 /************************************************************************
 3085                         Module routines
 3086 ************************************************************************/
 3087 
 3088 /*
 3089  * Handle the loading/unloading of a netgraph node type module
 3090  */
 3091 int
 3092 ng_mod_event(module_t mod, int event, void *data)
 3093 {
 3094         struct ng_type *const type = data;
 3095         int error = 0;
 3096 
 3097         switch (event) {
 3098         case MOD_LOAD:
 3099 
 3100                 /* Register new netgraph node type */
 3101                 if ((error = ng_newtype(type)) != 0)
 3102                         break;
 3103 
 3104                 /* Call type specific code */
 3105                 if (type->mod_event != NULL)
 3106                         if ((error = (*type->mod_event)(mod, event, data))) {
 3107                                 TYPELIST_WLOCK();
 3108                                 type->refs--;   /* undo it */
 3109                                 LIST_REMOVE(type, types);
 3110                                 TYPELIST_WUNLOCK();
 3111                         }
 3112                 break;
 3113 
 3114         case MOD_UNLOAD:
 3115                 if (type->refs > 1) {           /* make sure no nodes exist! */
 3116                         error = EBUSY;
 3117                 } else {
 3118                         if (type->refs == 0) /* failed load, nothing to undo */
 3119                                 break;
 3120                         if (type->mod_event != NULL) {  /* check with type */
 3121                                 error = (*type->mod_event)(mod, event, data);
 3122                                 if (error != 0) /* type refuses.. */
 3123                                         break;
 3124                         }
 3125                         TYPELIST_WLOCK();
 3126                         LIST_REMOVE(type, types);
 3127                         TYPELIST_WUNLOCK();
 3128                 }
 3129                 break;
 3130 
 3131         default:
 3132                 if (type->mod_event != NULL)
 3133                         error = (*type->mod_event)(mod, event, data);
 3134                 else
 3135                         error = EOPNOTSUPP;             /* XXX ? */
 3136                 break;
 3137         }
 3138         return (error);
 3139 }
 3140 
 3141 static void
 3142 vnet_netgraph_init(const void *unused __unused)
 3143 {
 3144 
 3145         /* We start with small hashes, but they can grow. */
 3146         V_ng_ID_hash = hashinit(16, M_NETGRAPH_NODE, &V_ng_ID_hmask);
 3147         V_ng_name_hash = hashinit(16, M_NETGRAPH_NODE, &V_ng_name_hmask);
 3148 }
 3149 VNET_SYSINIT(vnet_netgraph_init, SI_SUB_NETGRAPH, SI_ORDER_FIRST,
 3150     vnet_netgraph_init, NULL);
 3151 
 3152 #ifdef VIMAGE
 3153 static void
 3154 vnet_netgraph_uninit(const void *unused __unused)
 3155 {
 3156         node_p node = NULL, last_killed = NULL;
 3157         int i;
 3158 
 3159         do {
 3160                 /* Find a node to kill */
 3161                 IDHASH_RLOCK();
 3162                 for (i = 0; i <= V_ng_ID_hmask; i++) {
 3163                         LIST_FOREACH(node, &V_ng_ID_hash[i], nd_idnodes) {
 3164                                 if (node != &ng_deadnode) {
 3165                                         NG_NODE_REF(node);
 3166                                         break;
 3167                                 }
 3168                         }
 3169                         if (node != NULL)
 3170                                 break;
 3171                 }
 3172                 IDHASH_RUNLOCK();
 3173 
 3174                 /* Attempt to kill it only if it is a regular node */
 3175                 if (node != NULL) {
 3176                         if (node == last_killed) {
 3177                                 /* This should never happen */
 3178                                 printf("ng node %s needs NGF_REALLY_DIE\n",
 3179                                     node->nd_name);
 3180                                 if (node->nd_flags & NGF_REALLY_DIE)
 3181                                         panic("ng node %s won't die",
 3182                                             node->nd_name);
 3183                                 node->nd_flags |= NGF_REALLY_DIE;
 3184                         }
 3185                         ng_rmnode(node, NULL, NULL, 0);
 3186                         NG_NODE_UNREF(node);
 3187                         last_killed = node;
 3188                 }
 3189         } while (node != NULL);
 3190 
 3191         hashdestroy(V_ng_name_hash, M_NETGRAPH_NODE, V_ng_name_hmask);
 3192         hashdestroy(V_ng_ID_hash, M_NETGRAPH_NODE, V_ng_ID_hmask);
 3193 }
 3194 VNET_SYSUNINIT(vnet_netgraph_uninit, SI_SUB_NETGRAPH, SI_ORDER_FIRST,
 3195     vnet_netgraph_uninit, NULL);
 3196 #endif /* VIMAGE */
 3197 
 3198 /*
 3199  * Handle loading and unloading for this code.
 3200  * The only thing we need to link into is the NETISR strucure.
 3201  */
 3202 static int
 3203 ngb_mod_event(module_t mod, int event, void *data)
 3204 {
 3205         struct proc *p;
 3206         struct thread *td;
 3207         int i, error = 0;
 3208 
 3209         switch (event) {
 3210         case MOD_LOAD:
 3211                 /* Initialize everything. */
 3212                 NG_WORKLIST_LOCK_INIT();
 3213                 rw_init(&ng_typelist_lock, "netgraph types");
 3214                 rw_init(&ng_idhash_lock, "netgraph idhash");
 3215                 rw_init(&ng_namehash_lock, "netgraph namehash");
 3216                 rw_init(&ng_topo_lock, "netgraph topology mutex");
 3217 #ifdef  NETGRAPH_DEBUG
 3218                 mtx_init(&ng_nodelist_mtx, "netgraph nodelist mutex", NULL,
 3219                     MTX_DEF);
 3220                 mtx_init(&ngq_mtx, "netgraph item list mutex", NULL,
 3221                     MTX_DEF);
 3222 #endif
 3223                 ng_qzone = uma_zcreate("NetGraph items", sizeof(struct ng_item),
 3224                     NULL, NULL, NULL, NULL, UMA_ALIGN_CACHE, 0);
 3225                 uma_zone_set_max(ng_qzone, maxalloc);
 3226                 ng_qdzone = uma_zcreate("NetGraph data items",
 3227                     sizeof(struct ng_item), NULL, NULL, NULL, NULL,
 3228                     UMA_ALIGN_CACHE, 0);
 3229                 uma_zone_set_max(ng_qdzone, maxdata);
 3230                 /* Autoconfigure number of threads. */
 3231                 if (numthreads <= 0)
 3232                         numthreads = mp_ncpus;
 3233                 /* Create threads. */
 3234                 p = NULL; /* start with no process */
 3235                 for (i = 0; i < numthreads; i++) {
 3236                         if (kproc_kthread_add(ngthread, NULL, &p, &td,
 3237                             RFHIGHPID, 0, "ng_queue", "ng_queue%d", i)) {
 3238                                 numthreads = i;
 3239                                 break;
 3240                         }
 3241                 }
 3242                 break;
 3243         case MOD_UNLOAD:
 3244                 /* You can't unload it because an interface may be using it. */
 3245                 error = EBUSY;
 3246                 break;
 3247         default:
 3248                 error = EOPNOTSUPP;
 3249                 break;
 3250         }
 3251         return (error);
 3252 }
 3253 
 3254 static moduledata_t netgraph_mod = {
 3255         "netgraph",
 3256         ngb_mod_event,
 3257         (NULL)
 3258 };
 3259 DECLARE_MODULE(netgraph, netgraph_mod, SI_SUB_NETGRAPH, SI_ORDER_FIRST);
 3260 SYSCTL_NODE(_net, OID_AUTO, graph, CTLFLAG_RW, 0, "netgraph Family");
 3261 SYSCTL_INT(_net_graph, OID_AUTO, abi_version, CTLFLAG_RD, SYSCTL_NULL_INT_PTR, NG_ABI_VERSION,"");
 3262 SYSCTL_INT(_net_graph, OID_AUTO, msg_version, CTLFLAG_RD, SYSCTL_NULL_INT_PTR, NG_VERSION, "");
 3263 
 3264 #ifdef  NETGRAPH_DEBUG
 3265 void
 3266 dumphook (hook_p hook, char *file, int line)
 3267 {
 3268         printf("hook: name %s, %d refs, Last touched:\n",
 3269                 _NG_HOOK_NAME(hook), hook->hk_refs);
 3270         printf("        Last active @ %s, line %d\n",
 3271                 hook->lastfile, hook->lastline);
 3272         if (line) {
 3273                 printf(" problem discovered at file %s, line %d\n", file, line);
 3274 #ifdef KDB
 3275                 kdb_backtrace();
 3276 #endif
 3277         }
 3278 }
 3279 
 3280 void
 3281 dumpnode(node_p node, char *file, int line)
 3282 {
 3283         printf("node: ID [%x]: type '%s', %d hooks, flags 0x%x, %d refs, %s:\n",
 3284                 _NG_NODE_ID(node), node->nd_type->name,
 3285                 node->nd_numhooks, node->nd_flags,
 3286                 node->nd_refs, node->nd_name);
 3287         printf("        Last active @ %s, line %d\n",
 3288                 node->lastfile, node->lastline);
 3289         if (line) {
 3290                 printf(" problem discovered at file %s, line %d\n", file, line);
 3291 #ifdef KDB
 3292                 kdb_backtrace();
 3293 #endif
 3294         }
 3295 }
 3296 
 3297 void
 3298 dumpitem(item_p item, char *file, int line)
 3299 {
 3300         printf(" ACTIVE item, last used at %s, line %d",
 3301                 item->lastfile, item->lastline);
 3302         switch(item->el_flags & NGQF_TYPE) {
 3303         case NGQF_DATA:
 3304                 printf(" - [data]\n");
 3305                 break;
 3306         case NGQF_MESG:
 3307                 printf(" - retaddr[%d]:\n", _NGI_RETADDR(item));
 3308                 break;
 3309         case NGQF_FN:
 3310                 printf(" - fn@%p (%p, %p, %p, %d (%x))\n",
 3311                         _NGI_FN(item),
 3312                         _NGI_NODE(item),
 3313                         _NGI_HOOK(item),
 3314                         item->body.fn.fn_arg1,
 3315                         item->body.fn.fn_arg2,
 3316                         item->body.fn.fn_arg2);
 3317                 break;
 3318         case NGQF_FN2:
 3319                 printf(" - fn2@%p (%p, %p, %p, %d (%x))\n",
 3320                         _NGI_FN2(item),
 3321                         _NGI_NODE(item),
 3322                         _NGI_HOOK(item),
 3323                         item->body.fn.fn_arg1,
 3324                         item->body.fn.fn_arg2,
 3325                         item->body.fn.fn_arg2);
 3326                 break;
 3327         }
 3328         if (line) {
 3329                 printf(" problem discovered at file %s, line %d\n", file, line);
 3330                 if (_NGI_NODE(item)) {
 3331                         printf("node %p ([%x])\n",
 3332                                 _NGI_NODE(item), ng_node2ID(_NGI_NODE(item)));
 3333                 }
 3334         }
 3335 }
 3336 
 3337 static void
 3338 ng_dumpitems(void)
 3339 {
 3340         item_p item;
 3341         int i = 1;
 3342         TAILQ_FOREACH(item, &ng_itemlist, all) {
 3343                 printf("[%d] ", i++);
 3344                 dumpitem(item, NULL, 0);
 3345         }
 3346 }
 3347 
 3348 static void
 3349 ng_dumpnodes(void)
 3350 {
 3351         node_p node;
 3352         int i = 1;
 3353         mtx_lock(&ng_nodelist_mtx);
 3354         SLIST_FOREACH(node, &ng_allnodes, nd_all) {
 3355                 printf("[%d] ", i++);
 3356                 dumpnode(node, NULL, 0);
 3357         }
 3358         mtx_unlock(&ng_nodelist_mtx);
 3359 }
 3360 
 3361 static void
 3362 ng_dumphooks(void)
 3363 {
 3364         hook_p hook;
 3365         int i = 1;
 3366         mtx_lock(&ng_nodelist_mtx);
 3367         SLIST_FOREACH(hook, &ng_allhooks, hk_all) {
 3368                 printf("[%d] ", i++);
 3369                 dumphook(hook, NULL, 0);
 3370         }
 3371         mtx_unlock(&ng_nodelist_mtx);
 3372 }
 3373 
 3374 static int
 3375 sysctl_debug_ng_dump_items(SYSCTL_HANDLER_ARGS)
 3376 {
 3377         int error;
 3378         int val;
 3379         int i;
 3380 
 3381         val = allocated;
 3382         i = 1;
 3383         error = sysctl_handle_int(oidp, &val, 0, req);
 3384         if (error != 0 || req->newptr == NULL)
 3385                 return (error);
 3386         if (val == 42) {
 3387                 ng_dumpitems();
 3388                 ng_dumpnodes();
 3389                 ng_dumphooks();
 3390         }
 3391         return (0);
 3392 }
 3393 
 3394 SYSCTL_PROC(_debug, OID_AUTO, ng_dump_items, CTLTYPE_INT | CTLFLAG_RW,
 3395     0, sizeof(int), sysctl_debug_ng_dump_items, "I", "Number of allocated items");
 3396 #endif  /* NETGRAPH_DEBUG */
 3397 
 3398 /***********************************************************************
 3399 * Worklist routines
 3400 **********************************************************************/
 3401 /*
 3402  * Pick a node off the list of nodes with work,
 3403  * try get an item to process off it. Remove the node from the list.
 3404  */
 3405 static void
 3406 ngthread(void *arg)
 3407 {
 3408         for (;;) {
 3409                 node_p  node;
 3410 
 3411                 /* Get node from the worklist. */
 3412                 NG_WORKLIST_LOCK();
 3413                 while ((node = STAILQ_FIRST(&ng_worklist)) == NULL)
 3414                         NG_WORKLIST_SLEEP();
 3415                 STAILQ_REMOVE_HEAD(&ng_worklist, nd_input_queue.q_work);
 3416                 NG_WORKLIST_UNLOCK();
 3417                 CURVNET_SET(node->nd_vnet);
 3418                 CTR3(KTR_NET, "%20s: node [%x] (%p) taken off worklist",
 3419                     __func__, node->nd_ID, node);
 3420                 /*
 3421                  * We have the node. We also take over the reference
 3422                  * that the list had on it.
 3423                  * Now process as much as you can, until it won't
 3424                  * let you have another item off the queue.
 3425                  * All this time, keep the reference
 3426                  * that lets us be sure that the node still exists.
 3427                  * Let the reference go at the last minute.
 3428                  */
 3429                 for (;;) {
 3430                         item_p item;
 3431                         int rw;
 3432 
 3433                         NG_QUEUE_LOCK(&node->nd_input_queue);
 3434                         item = ng_dequeue(node, &rw);
 3435                         if (item == NULL) {
 3436                                 node->nd_input_queue.q_flags2 &= ~NGQ2_WORKQ;
 3437                                 NG_QUEUE_UNLOCK(&node->nd_input_queue);
 3438                                 break; /* go look for another node */
 3439                         } else {
 3440                                 NG_QUEUE_UNLOCK(&node->nd_input_queue);
 3441                                 NGI_GET_NODE(item, node); /* zaps stored node */
 3442                                 ng_apply_item(node, item, rw);
 3443                                 NG_NODE_UNREF(node);
 3444                         }
 3445                 }
 3446                 NG_NODE_UNREF(node);
 3447                 CURVNET_RESTORE();
 3448         }
 3449 }
 3450 
 3451 /*
 3452  * XXX
 3453  * It's posible that a debugging NG_NODE_REF may need
 3454  * to be outside the mutex zone
 3455  */
 3456 static void
 3457 ng_worklist_add(node_p node)
 3458 {
 3459 
 3460         mtx_assert(&node->nd_input_queue.q_mtx, MA_OWNED);
 3461 
 3462         if ((node->nd_input_queue.q_flags2 & NGQ2_WORKQ) == 0) {
 3463                 /*
 3464                  * If we are not already on the work queue,
 3465                  * then put us on.
 3466                  */
 3467                 node->nd_input_queue.q_flags2 |= NGQ2_WORKQ;
 3468                 NG_NODE_REF(node); /* XXX safe in mutex? */
 3469                 NG_WORKLIST_LOCK();
 3470                 STAILQ_INSERT_TAIL(&ng_worklist, node, nd_input_queue.q_work);
 3471                 NG_WORKLIST_UNLOCK();
 3472                 CTR3(KTR_NET, "%20s: node [%x] (%p) put on worklist", __func__,
 3473                     node->nd_ID, node);
 3474                 NG_WORKLIST_WAKEUP();
 3475         } else {
 3476                 CTR3(KTR_NET, "%20s: node [%x] (%p) already on worklist",
 3477                     __func__, node->nd_ID, node);
 3478         }
 3479 }
 3480 
 3481 /***********************************************************************
 3482 * Externally useable functions to set up a queue item ready for sending
 3483 ***********************************************************************/
 3484 
 3485 #ifdef  NETGRAPH_DEBUG
 3486 #define ITEM_DEBUG_CHECKS                                               \
 3487         do {                                                            \
 3488                 if (NGI_NODE(item) ) {                                  \
 3489                         printf("item already has node");                \
 3490                         kdb_enter(KDB_WHY_NETGRAPH, "has node");        \
 3491                         NGI_CLR_NODE(item);                             \
 3492                 }                                                       \
 3493                 if (NGI_HOOK(item) ) {                                  \
 3494                         printf("item already has hook");                \
 3495                         kdb_enter(KDB_WHY_NETGRAPH, "has hook");        \
 3496                         NGI_CLR_HOOK(item);                             \
 3497                 }                                                       \
 3498         } while (0)
 3499 #else
 3500 #define ITEM_DEBUG_CHECKS
 3501 #endif
 3502 
 3503 /*
 3504  * Put mbuf into the item.
 3505  * Hook and node references will be removed when the item is dequeued.
 3506  * (or equivalent)
 3507  * (XXX) Unsafe because no reference held by peer on remote node.
 3508  * remote node might go away in this timescale.
 3509  * We know the hooks can't go away because that would require getting
 3510  * a writer item on both nodes and we must have at least a  reader
 3511  * here to be able to do this.
 3512  * Note that the hook loaded is the REMOTE hook.
 3513  *
 3514  * This is possibly in the critical path for new data.
 3515  */
 3516 item_p
 3517 ng_package_data(struct mbuf *m, int flags)
 3518 {
 3519         item_p item;
 3520 
 3521         if ((item = ng_alloc_item(NGQF_DATA, flags)) == NULL) {
 3522                 NG_FREE_M(m);
 3523                 return (NULL);
 3524         }
 3525         ITEM_DEBUG_CHECKS;
 3526         item->el_flags |= NGQF_READER;
 3527         NGI_M(item) = m;
 3528         return (item);
 3529 }
 3530 
 3531 /*
 3532  * Allocate a queue item and put items into it..
 3533  * Evaluate the address as this will be needed to queue it and
 3534  * to work out what some of the fields should be.
 3535  * Hook and node references will be removed when the item is dequeued.
 3536  * (or equivalent)
 3537  */
 3538 item_p
 3539 ng_package_msg(struct ng_mesg *msg, int flags)
 3540 {
 3541         item_p item;
 3542 
 3543         if ((item = ng_alloc_item(NGQF_MESG, flags)) == NULL) {
 3544                 NG_FREE_MSG(msg);
 3545                 return (NULL);
 3546         }
 3547         ITEM_DEBUG_CHECKS;
 3548         /* Messages items count as writers unless explicitly exempted. */
 3549         if (msg->header.cmd & NGM_READONLY)
 3550                 item->el_flags |= NGQF_READER;
 3551         else
 3552                 item->el_flags |= NGQF_WRITER;
 3553         /*
 3554          * Set the current lasthook into the queue item
 3555          */
 3556         NGI_MSG(item) = msg;
 3557         NGI_RETADDR(item) = 0;
 3558         return (item);
 3559 }
 3560 
 3561 #define SET_RETADDR(item, here, retaddr)                                \
 3562         do {    /* Data or fn items don't have retaddrs */              \
 3563                 if ((item->el_flags & NGQF_TYPE) == NGQF_MESG) {        \
 3564                         if (retaddr) {                                  \
 3565                                 NGI_RETADDR(item) = retaddr;            \
 3566                         } else {                                        \
 3567                                 /*                                      \
 3568                                  * The old return address should be ok. \
 3569                                  * If there isn't one, use the address  \
 3570                                  * here.                                \
 3571                                  */                                     \
 3572                                 if (NGI_RETADDR(item) == 0) {           \
 3573                                         NGI_RETADDR(item)               \
 3574                                                 = ng_node2ID(here);     \
 3575                                 }                                       \
 3576                         }                                               \
 3577                 }                                                       \
 3578         } while (0)
 3579 
 3580 int
 3581 ng_address_hook(node_p here, item_p item, hook_p hook, ng_ID_t retaddr)
 3582 {
 3583         hook_p peer;
 3584         node_p peernode;
 3585         ITEM_DEBUG_CHECKS;
 3586         /*
 3587          * Quick sanity check..
 3588          * Since a hook holds a reference on it's node, once we know
 3589          * that the peer is still connected (even if invalid,) we know
 3590          * that the peer node is present, though maybe invalid.
 3591          */
 3592         TOPOLOGY_RLOCK();
 3593         if ((hook == NULL) || NG_HOOK_NOT_VALID(hook) ||
 3594             NG_HOOK_NOT_VALID(peer = NG_HOOK_PEER(hook)) ||
 3595             NG_NODE_NOT_VALID(peernode = NG_PEER_NODE(hook))) {
 3596                 NG_FREE_ITEM(item);
 3597                 TRAP_ERROR();
 3598                 TOPOLOGY_RUNLOCK();
 3599                 return (ENETDOWN);
 3600         }
 3601 
 3602         /*
 3603          * Transfer our interest to the other (peer) end.
 3604          */
 3605         NG_HOOK_REF(peer);
 3606         NG_NODE_REF(peernode);
 3607         NGI_SET_HOOK(item, peer);
 3608         NGI_SET_NODE(item, peernode);
 3609         SET_RETADDR(item, here, retaddr);
 3610 
 3611         TOPOLOGY_RUNLOCK();
 3612 
 3613         return (0);
 3614 }
 3615 
 3616 int
 3617 ng_address_path(node_p here, item_p item, const char *address, ng_ID_t retaddr)
 3618 {
 3619         node_p  dest = NULL;
 3620         hook_p  hook = NULL;
 3621         int     error;
 3622 
 3623         ITEM_DEBUG_CHECKS;
 3624         /*
 3625          * Note that ng_path2noderef increments the reference count
 3626          * on the node for us if it finds one. So we don't have to.
 3627          */
 3628         error = ng_path2noderef(here, address, &dest, &hook);
 3629         if (error) {
 3630                 NG_FREE_ITEM(item);
 3631                 return (error);
 3632         }
 3633         NGI_SET_NODE(item, dest);
 3634         if (hook)
 3635                 NGI_SET_HOOK(item, hook);
 3636 
 3637         SET_RETADDR(item, here, retaddr);
 3638         return (0);
 3639 }
 3640 
 3641 int
 3642 ng_address_ID(node_p here, item_p item, ng_ID_t ID, ng_ID_t retaddr)
 3643 {
 3644         node_p dest;
 3645 
 3646         ITEM_DEBUG_CHECKS;
 3647         /*
 3648          * Find the target node.
 3649          */
 3650         dest = ng_ID2noderef(ID); /* GETS REFERENCE! */
 3651         if (dest == NULL) {
 3652                 NG_FREE_ITEM(item);
 3653                 TRAP_ERROR();
 3654                 return(EINVAL);
 3655         }
 3656         /* Fill out the contents */
 3657         NGI_SET_NODE(item, dest);
 3658         NGI_CLR_HOOK(item);
 3659         SET_RETADDR(item, here, retaddr);
 3660         return (0);
 3661 }
 3662 
 3663 /*
 3664  * special case to send a message to self (e.g. destroy node)
 3665  * Possibly indicate an arrival hook too.
 3666  * Useful for removing that hook :-)
 3667  */
 3668 item_p
 3669 ng_package_msg_self(node_p here, hook_p hook, struct ng_mesg *msg)
 3670 {
 3671         item_p item;
 3672 
 3673         /*
 3674          * Find the target node.
 3675          * If there is a HOOK argument, then use that in preference
 3676          * to the address.
 3677          */
 3678         if ((item = ng_alloc_item(NGQF_MESG, NG_NOFLAGS)) == NULL) {
 3679                 NG_FREE_MSG(msg);
 3680                 return (NULL);
 3681         }
 3682 
 3683         /* Fill out the contents */
 3684         item->el_flags |= NGQF_WRITER;
 3685         NG_NODE_REF(here);
 3686         NGI_SET_NODE(item, here);
 3687         if (hook) {
 3688                 NG_HOOK_REF(hook);
 3689                 NGI_SET_HOOK(item, hook);
 3690         }
 3691         NGI_MSG(item) = msg;
 3692         NGI_RETADDR(item) = ng_node2ID(here);
 3693         return (item);
 3694 }
 3695 
 3696 /*
 3697  * Send ng_item_fn function call to the specified node.
 3698  */
 3699 
 3700 int
 3701 ng_send_fn(node_p node, hook_p hook, ng_item_fn *fn, void * arg1, int arg2)
 3702 {
 3703 
 3704         return ng_send_fn1(node, hook, fn, arg1, arg2, NG_NOFLAGS);
 3705 }
 3706 
 3707 int
 3708 ng_send_fn1(node_p node, hook_p hook, ng_item_fn *fn, void * arg1, int arg2,
 3709         int flags)
 3710 {
 3711         item_p item;
 3712 
 3713         if ((item = ng_alloc_item(NGQF_FN, flags)) == NULL) {
 3714                 return (ENOMEM);
 3715         }
 3716         item->el_flags |= NGQF_WRITER;
 3717         NG_NODE_REF(node); /* and one for the item */
 3718         NGI_SET_NODE(item, node);
 3719         if (hook) {
 3720                 NG_HOOK_REF(hook);
 3721                 NGI_SET_HOOK(item, hook);
 3722         }
 3723         NGI_FN(item) = fn;
 3724         NGI_ARG1(item) = arg1;
 3725         NGI_ARG2(item) = arg2;
 3726         return(ng_snd_item(item, flags));
 3727 }
 3728 
 3729 /*
 3730  * Send ng_item_fn2 function call to the specified node.
 3731  *
 3732  * If an optional pitem parameter is supplied, its apply
 3733  * callback will be copied to the new item. If also NG_REUSE_ITEM
 3734  * flag is set, no new item will be allocated, but pitem will
 3735  * be used.
 3736  */
 3737 int
 3738 ng_send_fn2(node_p node, hook_p hook, item_p pitem, ng_item_fn2 *fn, void *arg1,
 3739         int arg2, int flags)
 3740 {
 3741         item_p item;
 3742 
 3743         KASSERT((pitem != NULL || (flags & NG_REUSE_ITEM) == 0),
 3744             ("%s: NG_REUSE_ITEM but no pitem", __func__));
 3745 
 3746         /*
 3747          * Allocate a new item if no supplied or
 3748          * if we can't use supplied one.
 3749          */
 3750         if (pitem == NULL || (flags & NG_REUSE_ITEM) == 0) {
 3751                 if ((item = ng_alloc_item(NGQF_FN2, flags)) == NULL)
 3752                         return (ENOMEM);
 3753                 if (pitem != NULL)
 3754                         item->apply = pitem->apply;
 3755         } else {
 3756                 if ((item = ng_realloc_item(pitem, NGQF_FN2, flags)) == NULL)
 3757                         return (ENOMEM);
 3758         }
 3759 
 3760         item->el_flags = (item->el_flags & ~NGQF_RW) | NGQF_WRITER;
 3761         NG_NODE_REF(node); /* and one for the item */
 3762         NGI_SET_NODE(item, node);
 3763         if (hook) {
 3764                 NG_HOOK_REF(hook);
 3765                 NGI_SET_HOOK(item, hook);
 3766         }
 3767         NGI_FN2(item) = fn;
 3768         NGI_ARG1(item) = arg1;
 3769         NGI_ARG2(item) = arg2;
 3770         return(ng_snd_item(item, flags));
 3771 }
 3772 
 3773 /*
 3774  * Official timeout routines for Netgraph nodes.
 3775  */
 3776 static void
 3777 ng_callout_trampoline(void *arg)
 3778 {
 3779         item_p item = arg;
 3780 
 3781         CURVNET_SET(NGI_NODE(item)->nd_vnet);
 3782         ng_snd_item(item, 0);
 3783         CURVNET_RESTORE();
 3784 }
 3785 
 3786 int
 3787 ng_callout(struct callout *c, node_p node, hook_p hook, int ticks,
 3788     ng_item_fn *fn, void * arg1, int arg2)
 3789 {
 3790         item_p item, oitem;
 3791 
 3792         if ((item = ng_alloc_item(NGQF_FN, NG_NOFLAGS)) == NULL)
 3793                 return (ENOMEM);
 3794 
 3795         item->el_flags |= NGQF_WRITER;
 3796         NG_NODE_REF(node);              /* and one for the item */
 3797         NGI_SET_NODE(item, node);
 3798         if (hook) {
 3799                 NG_HOOK_REF(hook);
 3800                 NGI_SET_HOOK(item, hook);
 3801         }
 3802         NGI_FN(item) = fn;
 3803         NGI_ARG1(item) = arg1;
 3804         NGI_ARG2(item) = arg2;
 3805         oitem = c->c_arg;
 3806         if (callout_reset(c, ticks, &ng_callout_trampoline, item) == 1 &&
 3807             oitem != NULL)
 3808                 NG_FREE_ITEM(oitem);
 3809         return (0);
 3810 }
 3811 
 3812 /* A special modified version of untimeout() */
 3813 int
 3814 ng_uncallout(struct callout *c, node_p node)
 3815 {
 3816         item_p item;
 3817         int rval;
 3818 
 3819         KASSERT(c != NULL, ("ng_uncallout: NULL callout"));
 3820         KASSERT(node != NULL, ("ng_uncallout: NULL node"));
 3821 
 3822         rval = callout_stop(c);
 3823         item = c->c_arg;
 3824         /* Do an extra check */
 3825         if ((rval > 0) && (c->c_func == &ng_callout_trampoline) &&
 3826             (item != NULL) && (NGI_NODE(item) == node)) {
 3827                 /*
 3828                  * We successfully removed it from the queue before it ran
 3829                  * So now we need to unreference everything that was
 3830                  * given extra references. (NG_FREE_ITEM does this).
 3831                  */
 3832                 NG_FREE_ITEM(item);
 3833         }
 3834         c->c_arg = NULL;
 3835 
 3836         /*
 3837          * Callers only want to know if the callout was cancelled and
 3838          * not draining or stopped.
 3839          */
 3840         return (rval > 0);
 3841 }
 3842 
 3843 /*
 3844  * Set the address, if none given, give the node here.
 3845  */
 3846 void
 3847 ng_replace_retaddr(node_p here, item_p item, ng_ID_t retaddr)
 3848 {
 3849         if (retaddr) {
 3850                 NGI_RETADDR(item) = retaddr;
 3851         } else {
 3852                 /*
 3853                  * The old return address should be ok.
 3854                  * If there isn't one, use the address here.
 3855                  */
 3856                 NGI_RETADDR(item) = ng_node2ID(here);
 3857         }
 3858 }

Cache object: 24fbef1968189173597266debb84acd6


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]


This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.