The Design and Implementation of the FreeBSD Operating System, Second Edition
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sys/netgraph/ng_base.c

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    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: releng/11.1/sys/netgraph/ng_base.c 310248 2016-12-19 09:44:14Z hselasky $
   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         /* Check the name is valid */
  858         for (i = 0; i < NG_NODESIZ; i++) {
  859                 if (name[i] == '\0' || name[i] == '.' || name[i] == ':')
  860                         break;
  861         }
  862         if (i == 0 || name[i] != '\0') {
  863                 TRAP_ERROR();
  864                 return (EINVAL);
  865         }
  866         if (ng_decodeidname(name) != 0) { /* valid IDs not allowed here */
  867                 TRAP_ERROR();
  868                 return (EINVAL);
  869         }
  870 
  871         NAMEHASH_WLOCK();
  872         if (V_ng_named_nodes * 2 > V_ng_name_hmask)
  873                 ng_name_rehash();
  874 
  875         hash = hash32_str(name, HASHINIT) & V_ng_name_hmask;
  876         /* Check the name isn't already being used. */
  877         LIST_FOREACH(node2, &V_ng_name_hash[hash], nd_nodes)
  878                 if (NG_NODE_IS_VALID(node2) &&
  879                     (strcmp(NG_NODE_NAME(node2), name) == 0)) {
  880                         NAMEHASH_WUNLOCK();
  881                         return (EADDRINUSE);
  882                 }
  883 
  884         if (NG_NODE_HAS_NAME(node))
  885                 LIST_REMOVE(node, nd_nodes);
  886         else
  887                 V_ng_named_nodes++;
  888         /* Copy it. */
  889         strlcpy(NG_NODE_NAME(node), name, NG_NODESIZ);
  890         /* Update name hash. */
  891         LIST_INSERT_HEAD(&V_ng_name_hash[hash], node, nd_nodes);
  892         NAMEHASH_WUNLOCK();
  893 
  894         return (0);
  895 }
  896 
  897 /*
  898  * Find a node by absolute name. The name should NOT end with ':'
  899  * The name "." means "this node" and "[xxx]" means "the node
  900  * with ID (ie, at address) xxx".
  901  *
  902  * Returns the node if found, else NULL.
  903  * Eventually should add something faster than a sequential search.
  904  * Note it acquires a reference on the node so you can be sure it's still
  905  * there.
  906  */
  907 node_p
  908 ng_name2noderef(node_p here, const char *name)
  909 {
  910         node_p node;
  911         ng_ID_t temp;
  912         int     hash;
  913 
  914         /* "." means "this node" */
  915         if (strcmp(name, ".") == 0) {
  916                 NG_NODE_REF(here);
  917                 return(here);
  918         }
  919 
  920         /* Check for name-by-ID */
  921         if ((temp = ng_decodeidname(name)) != 0) {
  922                 return (ng_ID2noderef(temp));
  923         }
  924 
  925         /* Find node by name. */
  926         hash = hash32_str(name, HASHINIT) & V_ng_name_hmask;
  927         NAMEHASH_RLOCK();
  928         LIST_FOREACH(node, &V_ng_name_hash[hash], nd_nodes)
  929                 if (NG_NODE_IS_VALID(node) &&
  930                     (strcmp(NG_NODE_NAME(node), name) == 0)) {
  931                         NG_NODE_REF(node);
  932                         break;
  933                 }
  934         NAMEHASH_RUNLOCK();
  935 
  936         return (node);
  937 }
  938 
  939 /*
  940  * Decode an ID name, eg. "[f03034de]". Returns 0 if the
  941  * string is not valid, otherwise returns the value.
  942  */
  943 static ng_ID_t
  944 ng_decodeidname(const char *name)
  945 {
  946         const int len = strlen(name);
  947         char *eptr;
  948         u_long val;
  949 
  950         /* Check for proper length, brackets, no leading junk */
  951         if ((len < 3) || (name[0] != '[') || (name[len - 1] != ']') ||
  952             (!isxdigit(name[1])))
  953                 return ((ng_ID_t)0);
  954 
  955         /* Decode number */
  956         val = strtoul(name + 1, &eptr, 16);
  957         if ((eptr - name != len - 1) || (val == ULONG_MAX) || (val == 0))
  958                 return ((ng_ID_t)0);
  959 
  960         return ((ng_ID_t)val);
  961 }
  962 
  963 /*
  964  * Remove a name from a node. This should only be called
  965  * when shutting down and removing the node.
  966  */
  967 void
  968 ng_unname(node_p node)
  969 {
  970 }
  971 
  972 /*
  973  * Allocate a bigger name hash.
  974  */
  975 static void
  976 ng_name_rehash()
  977 {
  978         struct nodehash *new;
  979         uint32_t hash;
  980         u_long hmask;
  981         node_p node, node2;
  982         int i;
  983 
  984         new = hashinit_flags((V_ng_name_hmask + 1) * 2, M_NETGRAPH_NODE, &hmask,
  985             HASH_NOWAIT);
  986         if (new == NULL)
  987                 return;
  988 
  989         for (i = 0; i <= V_ng_name_hmask; i++)
  990                 LIST_FOREACH_SAFE(node, &V_ng_name_hash[i], nd_nodes, node2) {
  991 #ifdef INVARIANTS
  992                         LIST_REMOVE(node, nd_nodes);
  993 #endif
  994                         hash = hash32_str(NG_NODE_NAME(node), HASHINIT) & hmask;
  995                         LIST_INSERT_HEAD(&new[hash], node, nd_nodes);
  996                 }
  997 
  998         hashdestroy(V_ng_name_hash, M_NETGRAPH_NODE, V_ng_name_hmask);
  999         V_ng_name_hash = new;
 1000         V_ng_name_hmask = hmask;
 1001 }
 1002 
 1003 /*
 1004  * Allocate a bigger ID hash.
 1005  */
 1006 static void
 1007 ng_ID_rehash()
 1008 {
 1009         struct nodehash *new;
 1010         uint32_t hash;
 1011         u_long hmask;
 1012         node_p node, node2;
 1013         int i;
 1014 
 1015         new = hashinit_flags((V_ng_ID_hmask + 1) * 2, M_NETGRAPH_NODE, &hmask,
 1016             HASH_NOWAIT);
 1017         if (new == NULL)
 1018                 return;
 1019 
 1020         for (i = 0; i <= V_ng_ID_hmask; i++)
 1021                 LIST_FOREACH_SAFE(node, &V_ng_ID_hash[i], nd_idnodes, node2) {
 1022 #ifdef INVARIANTS
 1023                         LIST_REMOVE(node, nd_idnodes);
 1024 #endif
 1025                         hash = (node->nd_ID % (hmask + 1));
 1026                         LIST_INSERT_HEAD(&new[hash], node, nd_idnodes);
 1027                 }
 1028 
 1029         hashdestroy(V_ng_ID_hash, M_NETGRAPH_NODE, V_ng_name_hmask);
 1030         V_ng_ID_hash = new;
 1031         V_ng_ID_hmask = hmask;
 1032 }
 1033 
 1034 /************************************************************************
 1035                         Hook routines
 1036  Names are not optional. Hooks are always connected, except for a
 1037  brief moment within these routines. On invalidation or during creation
 1038  they are connected to the 'dead' hook.
 1039 ************************************************************************/
 1040 
 1041 /*
 1042  * Remove a hook reference
 1043  */
 1044 void
 1045 ng_unref_hook(hook_p hook)
 1046 {
 1047 
 1048         if (hook == &ng_deadhook)
 1049                 return;
 1050 
 1051         if (refcount_release(&hook->hk_refs)) { /* we were the last */
 1052                 if (_NG_HOOK_NODE(hook)) /* it'll probably be ng_deadnode */
 1053                         _NG_NODE_UNREF((_NG_HOOK_NODE(hook)));
 1054                 NG_FREE_HOOK(hook);
 1055         }
 1056 }
 1057 
 1058 /*
 1059  * Add an unconnected hook to a node. Only used internally.
 1060  * Assumes node is locked. (XXX not yet true )
 1061  */
 1062 static int
 1063 ng_add_hook(node_p node, const char *name, hook_p *hookp)
 1064 {
 1065         hook_p hook;
 1066         int error = 0;
 1067 
 1068         /* Check that the given name is good */
 1069         if (name == NULL) {
 1070                 TRAP_ERROR();
 1071                 return (EINVAL);
 1072         }
 1073         if (ng_findhook(node, name) != NULL) {
 1074                 TRAP_ERROR();
 1075                 return (EEXIST);
 1076         }
 1077 
 1078         /* Allocate the hook and link it up */
 1079         NG_ALLOC_HOOK(hook);
 1080         if (hook == NULL) {
 1081                 TRAP_ERROR();
 1082                 return (ENOMEM);
 1083         }
 1084         hook->hk_refs = 1;              /* add a reference for us to return */
 1085         hook->hk_flags = HK_INVALID;
 1086         hook->hk_peer = &ng_deadhook;   /* start off this way */
 1087         hook->hk_node = node;
 1088         NG_NODE_REF(node);              /* each hook counts as a reference */
 1089 
 1090         /* Set hook name */
 1091         strlcpy(NG_HOOK_NAME(hook), name, NG_HOOKSIZ);
 1092 
 1093         /*
 1094          * Check if the node type code has something to say about it
 1095          * If it fails, the unref of the hook will also unref the node.
 1096          */
 1097         if (node->nd_type->newhook != NULL) {
 1098                 if ((error = (*node->nd_type->newhook)(node, hook, name))) {
 1099                         NG_HOOK_UNREF(hook);    /* this frees the hook */
 1100                         return (error);
 1101                 }
 1102         }
 1103         /*
 1104          * The 'type' agrees so far, so go ahead and link it in.
 1105          * We'll ask again later when we actually connect the hooks.
 1106          */
 1107         LIST_INSERT_HEAD(&node->nd_hooks, hook, hk_hooks);
 1108         node->nd_numhooks++;
 1109         NG_HOOK_REF(hook);      /* one for the node */
 1110 
 1111         if (hookp)
 1112                 *hookp = hook;
 1113         return (0);
 1114 }
 1115 
 1116 /*
 1117  * Find a hook
 1118  *
 1119  * Node types may supply their own optimized routines for finding
 1120  * hooks.  If none is supplied, we just do a linear search.
 1121  * XXX Possibly we should add a reference to the hook?
 1122  */
 1123 hook_p
 1124 ng_findhook(node_p node, const char *name)
 1125 {
 1126         hook_p hook;
 1127 
 1128         if (node->nd_type->findhook != NULL)
 1129                 return (*node->nd_type->findhook)(node, name);
 1130         LIST_FOREACH(hook, &node->nd_hooks, hk_hooks) {
 1131                 if (NG_HOOK_IS_VALID(hook) &&
 1132                     (strcmp(NG_HOOK_NAME(hook), name) == 0))
 1133                         return (hook);
 1134         }
 1135         return (NULL);
 1136 }
 1137 
 1138 /*
 1139  * Destroy a hook
 1140  *
 1141  * As hooks are always attached, this really destroys two hooks.
 1142  * The one given, and the one attached to it. Disconnect the hooks
 1143  * from each other first. We reconnect the peer hook to the 'dead'
 1144  * hook so that it can still exist after we depart. We then
 1145  * send the peer its own destroy message. This ensures that we only
 1146  * interact with the peer's structures when it is locked processing that
 1147  * message. We hold a reference to the peer hook so we are guaranteed that
 1148  * the peer hook and node are still going to exist until
 1149  * we are finished there as the hook holds a ref on the node.
 1150  * We run this same code again on the peer hook, but that time it is already
 1151  * attached to the 'dead' hook.
 1152  *
 1153  * This routine is called at all stages of hook creation
 1154  * on error detection and must be able to handle any such stage.
 1155  */
 1156 void
 1157 ng_destroy_hook(hook_p hook)
 1158 {
 1159         hook_p peer;
 1160         node_p node;
 1161 
 1162         if (hook == &ng_deadhook) {     /* better safe than sorry */
 1163                 printf("ng_destroy_hook called on deadhook\n");
 1164                 return;
 1165         }
 1166 
 1167         /*
 1168          * Protect divorce process with mutex, to avoid races on
 1169          * simultaneous disconnect.
 1170          */
 1171         TOPOLOGY_WLOCK();
 1172 
 1173         hook->hk_flags |= HK_INVALID;
 1174 
 1175         peer = NG_HOOK_PEER(hook);
 1176         node = NG_HOOK_NODE(hook);
 1177 
 1178         if (peer && (peer != &ng_deadhook)) {
 1179                 /*
 1180                  * Set the peer to point to ng_deadhook
 1181                  * from this moment on we are effectively independent it.
 1182                  * send it an rmhook message of it's own.
 1183                  */
 1184                 peer->hk_peer = &ng_deadhook;   /* They no longer know us */
 1185                 hook->hk_peer = &ng_deadhook;   /* Nor us, them */
 1186                 if (NG_HOOK_NODE(peer) == &ng_deadnode) {
 1187                         /*
 1188                          * If it's already divorced from a node,
 1189                          * just free it.
 1190                          */
 1191                         TOPOLOGY_WUNLOCK();
 1192                 } else {
 1193                         TOPOLOGY_WUNLOCK();
 1194                         ng_rmhook_self(peer);   /* Send it a surprise */
 1195                 }
 1196                 NG_HOOK_UNREF(peer);            /* account for peer link */
 1197                 NG_HOOK_UNREF(hook);            /* account for peer link */
 1198         } else
 1199                 TOPOLOGY_WUNLOCK();
 1200 
 1201         TOPOLOGY_NOTOWNED();
 1202 
 1203         /*
 1204          * Remove the hook from the node's list to avoid possible recursion
 1205          * in case the disconnection results in node shutdown.
 1206          */
 1207         if (node == &ng_deadnode) { /* happens if called from ng_con_nodes() */
 1208                 return;
 1209         }
 1210         LIST_REMOVE(hook, hk_hooks);
 1211         node->nd_numhooks--;
 1212         if (node->nd_type->disconnect) {
 1213                 /*
 1214                  * The type handler may elect to destroy the node so don't
 1215                  * trust its existence after this point. (except
 1216                  * that we still hold a reference on it. (which we
 1217                  * inherrited from the hook we are destroying)
 1218                  */
 1219                 (*node->nd_type->disconnect) (hook);
 1220         }
 1221 
 1222         /*
 1223          * Note that because we will point to ng_deadnode, the original node
 1224          * is not decremented automatically so we do that manually.
 1225          */
 1226         _NG_HOOK_NODE(hook) = &ng_deadnode;
 1227         NG_NODE_UNREF(node);    /* We no longer point to it so adjust count */
 1228         NG_HOOK_UNREF(hook);    /* Account for linkage (in list) to node */
 1229 }
 1230 
 1231 /*
 1232  * Take two hooks on a node and merge the connection so that the given node
 1233  * is effectively bypassed.
 1234  */
 1235 int
 1236 ng_bypass(hook_p hook1, hook_p hook2)
 1237 {
 1238         if (hook1->hk_node != hook2->hk_node) {
 1239                 TRAP_ERROR();
 1240                 return (EINVAL);
 1241         }
 1242         TOPOLOGY_WLOCK();
 1243         if (NG_HOOK_NOT_VALID(hook1) || NG_HOOK_NOT_VALID(hook2)) {
 1244                 TOPOLOGY_WUNLOCK();
 1245                 return (EINVAL);
 1246         }
 1247         hook1->hk_peer->hk_peer = hook2->hk_peer;
 1248         hook2->hk_peer->hk_peer = hook1->hk_peer;
 1249 
 1250         hook1->hk_peer = &ng_deadhook;
 1251         hook2->hk_peer = &ng_deadhook;
 1252         TOPOLOGY_WUNLOCK();
 1253 
 1254         NG_HOOK_UNREF(hook1);
 1255         NG_HOOK_UNREF(hook2);
 1256 
 1257         /* XXX If we ever cache methods on hooks update them as well */
 1258         ng_destroy_hook(hook1);
 1259         ng_destroy_hook(hook2);
 1260         return (0);
 1261 }
 1262 
 1263 /*
 1264  * Install a new netgraph type
 1265  */
 1266 int
 1267 ng_newtype(struct ng_type *tp)
 1268 {
 1269         const size_t namelen = strlen(tp->name);
 1270 
 1271         /* Check version and type name fields */
 1272         if ((tp->version != NG_ABI_VERSION) || (namelen == 0) ||
 1273             (namelen >= NG_TYPESIZ)) {
 1274                 TRAP_ERROR();
 1275                 if (tp->version != NG_ABI_VERSION) {
 1276                         printf("Netgraph: Node type rejected. ABI mismatch. "
 1277                             "Suggest recompile\n");
 1278                 }
 1279                 return (EINVAL);
 1280         }
 1281 
 1282         /* Check for name collision */
 1283         if (ng_findtype(tp->name) != NULL) {
 1284                 TRAP_ERROR();
 1285                 return (EEXIST);
 1286         }
 1287 
 1288         /* Link in new type */
 1289         TYPELIST_WLOCK();
 1290         LIST_INSERT_HEAD(&ng_typelist, tp, types);
 1291         tp->refs = 1;   /* first ref is linked list */
 1292         TYPELIST_WUNLOCK();
 1293         return (0);
 1294 }
 1295 
 1296 /*
 1297  * unlink a netgraph type
 1298  * If no examples exist
 1299  */
 1300 int
 1301 ng_rmtype(struct ng_type *tp)
 1302 {
 1303         /* Check for name collision */
 1304         if (tp->refs != 1) {
 1305                 TRAP_ERROR();
 1306                 return (EBUSY);
 1307         }
 1308 
 1309         /* Unlink type */
 1310         TYPELIST_WLOCK();
 1311         LIST_REMOVE(tp, types);
 1312         TYPELIST_WUNLOCK();
 1313         return (0);
 1314 }
 1315 
 1316 /*
 1317  * Look for a type of the name given
 1318  */
 1319 struct ng_type *
 1320 ng_findtype(const char *typename)
 1321 {
 1322         struct ng_type *type;
 1323 
 1324         TYPELIST_RLOCK();
 1325         LIST_FOREACH(type, &ng_typelist, types) {
 1326                 if (strcmp(type->name, typename) == 0)
 1327                         break;
 1328         }
 1329         TYPELIST_RUNLOCK();
 1330         return (type);
 1331 }
 1332 
 1333 /************************************************************************
 1334                         Composite routines
 1335 ************************************************************************/
 1336 /*
 1337  * Connect two nodes using the specified hooks, using queued functions.
 1338  */
 1339 static int
 1340 ng_con_part3(node_p node, item_p item, hook_p hook)
 1341 {
 1342         int     error = 0;
 1343 
 1344         /*
 1345          * When we run, we know that the node 'node' is locked for us.
 1346          * Our caller has a reference on the hook.
 1347          * Our caller has a reference on the node.
 1348          * (In this case our caller is ng_apply_item() ).
 1349          * The peer hook has a reference on the hook.
 1350          * We are all set up except for the final call to the node, and
 1351          * the clearing of the INVALID flag.
 1352          */
 1353         if (NG_HOOK_NODE(hook) == &ng_deadnode) {
 1354                 /*
 1355                  * The node must have been freed again since we last visited
 1356                  * here. ng_destry_hook() has this effect but nothing else does.
 1357                  * We should just release our references and
 1358                  * free anything we can think of.
 1359                  * Since we know it's been destroyed, and it's our caller
 1360                  * that holds the references, just return.
 1361                  */
 1362                 ERROUT(ENOENT);
 1363         }
 1364         if (hook->hk_node->nd_type->connect) {
 1365                 if ((error = (*hook->hk_node->nd_type->connect) (hook))) {
 1366                         ng_destroy_hook(hook);  /* also zaps peer */
 1367                         printf("failed in ng_con_part3()\n");
 1368                         ERROUT(error);
 1369                 }
 1370         }
 1371         /*
 1372          *  XXX this is wrong for SMP. Possibly we need
 1373          * to separate out 'create' and 'invalid' flags.
 1374          * should only set flags on hooks we have locked under our node.
 1375          */
 1376         hook->hk_flags &= ~HK_INVALID;
 1377 done:
 1378         NG_FREE_ITEM(item);
 1379         return (error);
 1380 }
 1381 
 1382 static int
 1383 ng_con_part2(node_p node, item_p item, hook_p hook)
 1384 {
 1385         hook_p  peer;
 1386         int     error = 0;
 1387 
 1388         /*
 1389          * When we run, we know that the node 'node' is locked for us.
 1390          * Our caller has a reference on the hook.
 1391          * Our caller has a reference on the node.
 1392          * (In this case our caller is ng_apply_item() ).
 1393          * The peer hook has a reference on the hook.
 1394          * our node pointer points to the 'dead' node.
 1395          * First check the hook name is unique.
 1396          * Should not happen because we checked before queueing this.
 1397          */
 1398         if (ng_findhook(node, NG_HOOK_NAME(hook)) != NULL) {
 1399                 TRAP_ERROR();
 1400                 ng_destroy_hook(hook); /* should destroy peer too */
 1401                 printf("failed in ng_con_part2()\n");
 1402                 ERROUT(EEXIST);
 1403         }
 1404         /*
 1405          * Check if the node type code has something to say about it
 1406          * If it fails, the unref of the hook will also unref the attached node,
 1407          * however since that node is 'ng_deadnode' this will do nothing.
 1408          * The peer hook will also be destroyed.
 1409          */
 1410         if (node->nd_type->newhook != NULL) {
 1411                 if ((error = (*node->nd_type->newhook)(node, hook,
 1412                     hook->hk_name))) {
 1413                         ng_destroy_hook(hook); /* should destroy peer too */
 1414                         printf("failed in ng_con_part2()\n");
 1415                         ERROUT(error);
 1416                 }
 1417         }
 1418 
 1419         /*
 1420          * The 'type' agrees so far, so go ahead and link it in.
 1421          * We'll ask again later when we actually connect the hooks.
 1422          */
 1423         hook->hk_node = node;           /* just overwrite ng_deadnode */
 1424         NG_NODE_REF(node);              /* each hook counts as a reference */
 1425         LIST_INSERT_HEAD(&node->nd_hooks, hook, hk_hooks);
 1426         node->nd_numhooks++;
 1427         NG_HOOK_REF(hook);      /* one for the node */
 1428         
 1429         /*
 1430          * We now have a symmetrical situation, where both hooks have been
 1431          * linked to their nodes, the newhook methods have been called
 1432          * And the references are all correct. The hooks are still marked
 1433          * as invalid, as we have not called the 'connect' methods
 1434          * yet.
 1435          * We can call the local one immediately as we have the
 1436          * node locked, but we need to queue the remote one.
 1437          */
 1438         if (hook->hk_node->nd_type->connect) {
 1439                 if ((error = (*hook->hk_node->nd_type->connect) (hook))) {
 1440                         ng_destroy_hook(hook);  /* also zaps peer */
 1441                         printf("failed in ng_con_part2(A)\n");
 1442                         ERROUT(error);
 1443                 }
 1444         }
 1445 
 1446         /*
 1447          * Acquire topo mutex to avoid race with ng_destroy_hook().
 1448          */
 1449         TOPOLOGY_RLOCK();
 1450         peer = hook->hk_peer;
 1451         if (peer == &ng_deadhook) {
 1452                 TOPOLOGY_RUNLOCK();
 1453                 printf("failed in ng_con_part2(B)\n");
 1454                 ng_destroy_hook(hook);
 1455                 ERROUT(ENOENT);
 1456         }
 1457         TOPOLOGY_RUNLOCK();
 1458 
 1459         if ((error = ng_send_fn2(peer->hk_node, peer, item, &ng_con_part3,
 1460             NULL, 0, NG_REUSE_ITEM))) {
 1461                 printf("failed in ng_con_part2(C)\n");
 1462                 ng_destroy_hook(hook);  /* also zaps peer */
 1463                 return (error);         /* item was consumed. */
 1464         }
 1465         hook->hk_flags &= ~HK_INVALID; /* need both to be able to work */
 1466         return (0);                     /* item was consumed. */
 1467 done:
 1468         NG_FREE_ITEM(item);
 1469         return (error);
 1470 }
 1471 
 1472 /*
 1473  * Connect this node with another node. We assume that this node is
 1474  * currently locked, as we are only called from an NGM_CONNECT message.
 1475  */
 1476 static int
 1477 ng_con_nodes(item_p item, node_p node, const char *name,
 1478     node_p node2, const char *name2)
 1479 {
 1480         int     error;
 1481         hook_p  hook;
 1482         hook_p  hook2;
 1483 
 1484         if (ng_findhook(node2, name2) != NULL) {
 1485                 return(EEXIST);
 1486         }
 1487         if ((error = ng_add_hook(node, name, &hook)))  /* gives us a ref */
 1488                 return (error);
 1489         /* Allocate the other hook and link it up */
 1490         NG_ALLOC_HOOK(hook2);
 1491         if (hook2 == NULL) {
 1492                 TRAP_ERROR();
 1493                 ng_destroy_hook(hook);  /* XXX check ref counts so far */
 1494                 NG_HOOK_UNREF(hook);    /* including our ref */
 1495                 return (ENOMEM);
 1496         }
 1497         hook2->hk_refs = 1;             /* start with a reference for us. */
 1498         hook2->hk_flags = HK_INVALID;
 1499         hook2->hk_peer = hook;          /* Link the two together */
 1500         hook->hk_peer = hook2;  
 1501         NG_HOOK_REF(hook);              /* Add a ref for the peer to each*/
 1502         NG_HOOK_REF(hook2);
 1503         hook2->hk_node = &ng_deadnode;
 1504         strlcpy(NG_HOOK_NAME(hook2), name2, NG_HOOKSIZ);
 1505 
 1506         /*
 1507          * Queue the function above.
 1508          * Procesing continues in that function in the lock context of
 1509          * the other node.
 1510          */
 1511         if ((error = ng_send_fn2(node2, hook2, item, &ng_con_part2, NULL, 0,
 1512             NG_NOFLAGS))) {
 1513                 printf("failed in ng_con_nodes(): %d\n", error);
 1514                 ng_destroy_hook(hook);  /* also zaps peer */
 1515         }
 1516 
 1517         NG_HOOK_UNREF(hook);            /* Let each hook go if it wants to */
 1518         NG_HOOK_UNREF(hook2);
 1519         return (error);
 1520 }
 1521 
 1522 /*
 1523  * Make a peer and connect.
 1524  * We assume that the local node is locked.
 1525  * The new node probably doesn't need a lock until
 1526  * it has a hook, because it cannot really have any work until then,
 1527  * but we should think about it a bit more.
 1528  *
 1529  * The problem may come if the other node also fires up
 1530  * some hardware or a timer or some other source of activation,
 1531  * also it may already get a command msg via it's ID.
 1532  *
 1533  * We could use the same method as ng_con_nodes() but we'd have
 1534  * to add ability to remove the node when failing. (Not hard, just
 1535  * make arg1 point to the node to remove).
 1536  * Unless of course we just ignore failure to connect and leave
 1537  * an unconnected node?
 1538  */
 1539 static int
 1540 ng_mkpeer(node_p node, const char *name, const char *name2, char *type)
 1541 {
 1542         node_p  node2;
 1543         hook_p  hook1, hook2;
 1544         int     error;
 1545 
 1546         if ((error = ng_make_node(type, &node2))) {
 1547                 return (error);
 1548         }
 1549 
 1550         if ((error = ng_add_hook(node, name, &hook1))) { /* gives us a ref */
 1551                 ng_rmnode(node2, NULL, NULL, 0);
 1552                 return (error);
 1553         }
 1554 
 1555         if ((error = ng_add_hook(node2, name2, &hook2))) {
 1556                 ng_rmnode(node2, NULL, NULL, 0);
 1557                 ng_destroy_hook(hook1);
 1558                 NG_HOOK_UNREF(hook1);
 1559                 return (error);
 1560         }
 1561 
 1562         /*
 1563          * Actually link the two hooks together.
 1564          */
 1565         hook1->hk_peer = hook2;
 1566         hook2->hk_peer = hook1;
 1567 
 1568         /* Each hook is referenced by the other */
 1569         NG_HOOK_REF(hook1);
 1570         NG_HOOK_REF(hook2);
 1571 
 1572         /* Give each node the opportunity to veto the pending connection */
 1573         if (hook1->hk_node->nd_type->connect) {
 1574                 error = (*hook1->hk_node->nd_type->connect) (hook1);
 1575         }
 1576 
 1577         if ((error == 0) && hook2->hk_node->nd_type->connect) {
 1578                 error = (*hook2->hk_node->nd_type->connect) (hook2);
 1579 
 1580         }
 1581 
 1582         /*
 1583          * drop the references we were holding on the two hooks.
 1584          */
 1585         if (error) {
 1586                 ng_destroy_hook(hook2); /* also zaps hook1 */
 1587                 ng_rmnode(node2, NULL, NULL, 0);
 1588         } else {
 1589                 /* As a last act, allow the hooks to be used */
 1590                 hook1->hk_flags &= ~HK_INVALID;
 1591                 hook2->hk_flags &= ~HK_INVALID;
 1592         }
 1593         NG_HOOK_UNREF(hook1);
 1594         NG_HOOK_UNREF(hook2);
 1595         return (error);
 1596 }
 1597 
 1598 /************************************************************************
 1599                 Utility routines to send self messages
 1600 ************************************************************************/
 1601         
 1602 /* Shut this node down as soon as everyone is clear of it */
 1603 /* Should add arg "immediately" to jump the queue */
 1604 int
 1605 ng_rmnode_self(node_p node)
 1606 {
 1607         int             error;
 1608 
 1609         if (node == &ng_deadnode)
 1610                 return (0);
 1611         node->nd_flags |= NGF_INVALID;
 1612         if (node->nd_flags & NGF_CLOSING)
 1613                 return (0);
 1614 
 1615         error = ng_send_fn(node, NULL, &ng_rmnode, NULL, 0);
 1616         return (error);
 1617 }
 1618 
 1619 static void
 1620 ng_rmhook_part2(node_p node, hook_p hook, void *arg1, int arg2)
 1621 {
 1622         ng_destroy_hook(hook);
 1623         return ;
 1624 }
 1625 
 1626 int
 1627 ng_rmhook_self(hook_p hook)
 1628 {
 1629         int             error;
 1630         node_p node = NG_HOOK_NODE(hook);
 1631 
 1632         if (node == &ng_deadnode)
 1633                 return (0);
 1634 
 1635         error = ng_send_fn(node, hook, &ng_rmhook_part2, NULL, 0);
 1636         return (error);
 1637 }
 1638 
 1639 /***********************************************************************
 1640  * Parse and verify a string of the form:  <NODE:><PATH>
 1641  *
 1642  * Such a string can refer to a specific node or a specific hook
 1643  * on a specific node, depending on how you look at it. In the
 1644  * latter case, the PATH component must not end in a dot.
 1645  *
 1646  * Both <NODE:> and <PATH> are optional. The <PATH> is a string
 1647  * of hook names separated by dots. This breaks out the original
 1648  * string, setting *nodep to "NODE" (or NULL if none) and *pathp
 1649  * to "PATH" (or NULL if degenerate). Also, *hookp will point to
 1650  * the final hook component of <PATH>, if any, otherwise NULL.
 1651  *
 1652  * This returns -1 if the path is malformed. The char ** are optional.
 1653  ***********************************************************************/
 1654 int
 1655 ng_path_parse(char *addr, char **nodep, char **pathp, char **hookp)
 1656 {
 1657         char    *node, *path, *hook;
 1658         int     k;
 1659 
 1660         /*
 1661          * Extract absolute NODE, if any
 1662          */
 1663         for (path = addr; *path && *path != ':'; path++);
 1664         if (*path) {
 1665                 node = addr;    /* Here's the NODE */
 1666                 *path++ = '\0'; /* Here's the PATH */
 1667 
 1668                 /* Node name must not be empty */
 1669                 if (!*node)
 1670                         return -1;
 1671 
 1672                 /* A name of "." is OK; otherwise '.' not allowed */
 1673                 if (strcmp(node, ".") != 0) {
 1674                         for (k = 0; node[k]; k++)
 1675                                 if (node[k] == '.')
 1676                                         return -1;
 1677                 }
 1678         } else {
 1679                 node = NULL;    /* No absolute NODE */
 1680                 path = addr;    /* Here's the PATH */
 1681         }
 1682 
 1683         /* Snoop for illegal characters in PATH */
 1684         for (k = 0; path[k]; k++)
 1685                 if (path[k] == ':')
 1686                         return -1;
 1687 
 1688         /* Check for no repeated dots in PATH */
 1689         for (k = 0; path[k]; k++)
 1690                 if (path[k] == '.' && path[k + 1] == '.')
 1691                         return -1;
 1692 
 1693         /* Remove extra (degenerate) dots from beginning or end of PATH */
 1694         if (path[0] == '.')
 1695                 path++;
 1696         if (*path && path[strlen(path) - 1] == '.')
 1697                 path[strlen(path) - 1] = 0;
 1698 
 1699         /* If PATH has a dot, then we're not talking about a hook */
 1700         if (*path) {
 1701                 for (hook = path, k = 0; path[k]; k++)
 1702                         if (path[k] == '.') {
 1703                                 hook = NULL;
 1704                                 break;
 1705                         }
 1706         } else
 1707                 path = hook = NULL;
 1708 
 1709         /* Done */
 1710         if (nodep)
 1711                 *nodep = node;
 1712         if (pathp)
 1713                 *pathp = path;
 1714         if (hookp)
 1715                 *hookp = hook;
 1716         return (0);
 1717 }
 1718 
 1719 /*
 1720  * Given a path, which may be absolute or relative, and a starting node,
 1721  * return the destination node.
 1722  */
 1723 int
 1724 ng_path2noderef(node_p here, const char *address, node_p *destp,
 1725     hook_p *lasthook)
 1726 {
 1727         char    fullpath[NG_PATHSIZ];
 1728         char   *nodename, *path;
 1729         node_p  node, oldnode;
 1730 
 1731         /* Initialize */
 1732         if (destp == NULL) {
 1733                 TRAP_ERROR();
 1734                 return EINVAL;
 1735         }
 1736         *destp = NULL;
 1737 
 1738         /* Make a writable copy of address for ng_path_parse() */
 1739         strncpy(fullpath, address, sizeof(fullpath) - 1);
 1740         fullpath[sizeof(fullpath) - 1] = '\0';
 1741 
 1742         /* Parse out node and sequence of hooks */
 1743         if (ng_path_parse(fullpath, &nodename, &path, NULL) < 0) {
 1744                 TRAP_ERROR();
 1745                 return EINVAL;
 1746         }
 1747 
 1748         /*
 1749          * For an absolute address, jump to the starting node.
 1750          * Note that this holds a reference on the node for us.
 1751          * Don't forget to drop the reference if we don't need it.
 1752          */
 1753         if (nodename) {
 1754                 node = ng_name2noderef(here, nodename);
 1755                 if (node == NULL) {
 1756                         TRAP_ERROR();
 1757                         return (ENOENT);
 1758                 }
 1759         } else {
 1760                 if (here == NULL) {
 1761                         TRAP_ERROR();
 1762                         return (EINVAL);
 1763                 }
 1764                 node = here;
 1765                 NG_NODE_REF(node);
 1766         }
 1767 
 1768         if (path == NULL) {
 1769                 if (lasthook != NULL)
 1770                         *lasthook = NULL;
 1771                 *destp = node;
 1772                 return (0);
 1773         }
 1774 
 1775         /*
 1776          * Now follow the sequence of hooks
 1777          *
 1778          * XXXGL: The path may demolish as we go the sequence, but if
 1779          * we hold the topology mutex at critical places, then, I hope,
 1780          * we would always have valid pointers in hand, although the
 1781          * path behind us may no longer exist.
 1782          */
 1783         for (;;) {
 1784                 hook_p hook;
 1785                 char *segment;
 1786 
 1787                 /*
 1788                  * Break out the next path segment. Replace the dot we just
 1789                  * found with a NUL; "path" points to the next segment (or the
 1790                  * NUL at the end).
 1791                  */
 1792                 for (segment = path; *path != '\0'; path++) {
 1793                         if (*path == '.') {
 1794                                 *path++ = '\0';
 1795                                 break;
 1796                         }
 1797                 }
 1798 
 1799                 /* We have a segment, so look for a hook by that name */
 1800                 hook = ng_findhook(node, segment);
 1801 
 1802                 TOPOLOGY_WLOCK();
 1803                 /* Can't get there from here... */
 1804                 if (hook == NULL || NG_HOOK_PEER(hook) == NULL ||
 1805                     NG_HOOK_NOT_VALID(hook) ||
 1806                     NG_HOOK_NOT_VALID(NG_HOOK_PEER(hook))) {
 1807                         TRAP_ERROR();
 1808                         NG_NODE_UNREF(node);
 1809                         TOPOLOGY_WUNLOCK();
 1810                         return (ENOENT);
 1811                 }
 1812 
 1813                 /*
 1814                  * Hop on over to the next node
 1815                  * XXX
 1816                  * Big race conditions here as hooks and nodes go away
 1817                  * *** Idea.. store an ng_ID_t in each hook and use that
 1818                  * instead of the direct hook in this crawl?
 1819                  */
 1820                 oldnode = node;
 1821                 if ((node = NG_PEER_NODE(hook)))
 1822                         NG_NODE_REF(node);      /* XXX RACE */
 1823                 NG_NODE_UNREF(oldnode); /* XXX another race */
 1824                 if (NG_NODE_NOT_VALID(node)) {
 1825                         NG_NODE_UNREF(node);    /* XXX more races */
 1826                         TOPOLOGY_WUNLOCK();
 1827                         TRAP_ERROR();
 1828                         return (ENXIO);
 1829                 }
 1830 
 1831                 if (*path == '\0') {
 1832                         if (lasthook != NULL) {
 1833                                 if (hook != NULL) {
 1834                                         *lasthook = NG_HOOK_PEER(hook);
 1835                                         NG_HOOK_REF(*lasthook);
 1836                                 } else
 1837                                         *lasthook = NULL;
 1838                         }
 1839                         TOPOLOGY_WUNLOCK();
 1840                         *destp = node;
 1841                         return (0);
 1842                 }
 1843                 TOPOLOGY_WUNLOCK();
 1844         }
 1845 }
 1846 
 1847 /***************************************************************\
 1848 * Input queue handling.
 1849 * All activities are submitted to the node via the input queue
 1850 * which implements a multiple-reader/single-writer gate.
 1851 * Items which cannot be handled immediately are queued.
 1852 *
 1853 * read-write queue locking inline functions                     *
 1854 \***************************************************************/
 1855 
 1856 static __inline void    ng_queue_rw(node_p node, item_p  item, int rw);
 1857 static __inline item_p  ng_dequeue(node_p node, int *rw);
 1858 static __inline item_p  ng_acquire_read(node_p node, item_p  item);
 1859 static __inline item_p  ng_acquire_write(node_p node, item_p  item);
 1860 static __inline void    ng_leave_read(node_p node);
 1861 static __inline void    ng_leave_write(node_p node);
 1862 
 1863 /*
 1864  * Definition of the bits fields in the ng_queue flag word.
 1865  * Defined here rather than in netgraph.h because no-one should fiddle
 1866  * with them.
 1867  *
 1868  * The ordering here may be important! don't shuffle these.
 1869  */
 1870 /*-
 1871  Safety Barrier--------+ (adjustable to suit taste) (not used yet)
 1872                        |
 1873                        V
 1874 +-------+-------+-------+-------+-------+-------+-------+-------+
 1875   | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
 1876   | |A|c|t|i|v|e| |R|e|a|d|e|r| |C|o|u|n|t| | | | | | | | | |P|A|
 1877   | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |O|W|
 1878 +-------+-------+-------+-------+-------+-------+-------+-------+
 1879   \___________________________ ____________________________/ | |
 1880                             V                                | |
 1881                   [active reader count]                      | |
 1882                                                              | |
 1883             Operation Pending -------------------------------+ |
 1884                                                                |
 1885           Active Writer ---------------------------------------+
 1886 
 1887 Node queue has such semantics:
 1888 - All flags modifications are atomic.
 1889 - Reader count can be incremented only if there is no writer or pending flags.
 1890   As soon as this can't be done with single operation, it is implemented with
 1891   spin loop and atomic_cmpset().
 1892 - Writer flag can be set only if there is no any bits set.
 1893   It is implemented with atomic_cmpset().
 1894 - Pending flag can be set any time, but to avoid collision on queue processing
 1895   all queue fields are protected by the mutex.
 1896 - Queue processing thread reads queue holding the mutex, but releases it while
 1897   processing. When queue is empty pending flag is removed.
 1898 */
 1899 
 1900 #define WRITER_ACTIVE   0x00000001
 1901 #define OP_PENDING      0x00000002
 1902 #define READER_INCREMENT 0x00000004
 1903 #define READER_MASK     0xfffffffc      /* Not valid if WRITER_ACTIVE is set */
 1904 #define SAFETY_BARRIER  0x00100000      /* 128K items queued should be enough */
 1905 
 1906 /* Defines of more elaborate states on the queue */
 1907 /* Mask of bits a new read cares about */
 1908 #define NGQ_RMASK       (WRITER_ACTIVE|OP_PENDING)
 1909 
 1910 /* Mask of bits a new write cares about */
 1911 #define NGQ_WMASK       (NGQ_RMASK|READER_MASK)
 1912 
 1913 /* Test to decide if there is something on the queue. */
 1914 #define QUEUE_ACTIVE(QP) ((QP)->q_flags & OP_PENDING)
 1915 
 1916 /* How to decide what the next queued item is. */
 1917 #define HEAD_IS_READER(QP)  NGI_QUEUED_READER(STAILQ_FIRST(&(QP)->queue))
 1918 #define HEAD_IS_WRITER(QP)  NGI_QUEUED_WRITER(STAILQ_FIRST(&(QP)->queue)) /* notused */
 1919 
 1920 /* Read the status to decide if the next item on the queue can now run. */
 1921 #define QUEUED_READER_CAN_PROCEED(QP)                   \
 1922                 (((QP)->q_flags & (NGQ_RMASK & ~OP_PENDING)) == 0)
 1923 #define QUEUED_WRITER_CAN_PROCEED(QP)                   \
 1924                 (((QP)->q_flags & (NGQ_WMASK & ~OP_PENDING)) == 0)
 1925 
 1926 /* Is there a chance of getting ANY work off the queue? */
 1927 #define NEXT_QUEUED_ITEM_CAN_PROCEED(QP)                                \
 1928         ((HEAD_IS_READER(QP)) ? QUEUED_READER_CAN_PROCEED(QP) :         \
 1929                                 QUEUED_WRITER_CAN_PROCEED(QP))
 1930 
 1931 #define NGQRW_R 0
 1932 #define NGQRW_W 1
 1933 
 1934 #define NGQ2_WORKQ      0x00000001
 1935 
 1936 /*
 1937  * Taking into account the current state of the queue and node, possibly take
 1938  * the next entry off the queue and return it. Return NULL if there was
 1939  * nothing we could return, either because there really was nothing there, or
 1940  * because the node was in a state where it cannot yet process the next item
 1941  * on the queue.
 1942  */
 1943 static __inline item_p
 1944 ng_dequeue(node_p node, int *rw)
 1945 {
 1946         item_p item;
 1947         struct ng_queue *ngq = &node->nd_input_queue;
 1948 
 1949         /* This MUST be called with the mutex held. */
 1950         mtx_assert(&ngq->q_mtx, MA_OWNED);
 1951 
 1952         /* If there is nothing queued, then just return. */
 1953         if (!QUEUE_ACTIVE(ngq)) {
 1954                 CTR4(KTR_NET, "%20s: node [%x] (%p) queue empty; "
 1955                     "queue flags 0x%lx", __func__,
 1956                     node->nd_ID, node, ngq->q_flags);
 1957                 return (NULL);
 1958         }
 1959 
 1960         /*
 1961          * From here, we can assume there is a head item.
 1962          * We need to find out what it is and if it can be dequeued, given
 1963          * the current state of the node.
 1964          */
 1965         if (HEAD_IS_READER(ngq)) {
 1966                 while (1) {
 1967                         long t = ngq->q_flags;
 1968                         if (t & WRITER_ACTIVE) {
 1969                                 /* There is writer, reader can't proceed. */
 1970                                 CTR4(KTR_NET, "%20s: node [%x] (%p) queued "
 1971                                     "reader can't proceed; queue flags 0x%lx",
 1972                                     __func__, node->nd_ID, node, t);
 1973                                 return (NULL);
 1974                         }
 1975                         if (atomic_cmpset_acq_int(&ngq->q_flags, t,
 1976                             t + READER_INCREMENT))
 1977                                 break;
 1978                         cpu_spinwait();
 1979                 }
 1980                 /* We have got reader lock for the node. */
 1981                 *rw = NGQRW_R;
 1982         } else if (atomic_cmpset_acq_int(&ngq->q_flags, OP_PENDING,
 1983             OP_PENDING + WRITER_ACTIVE)) {
 1984                 /* We have got writer lock for the node. */
 1985                 *rw = NGQRW_W;
 1986         } else {
 1987                 /* There is somebody other, writer can't proceed. */
 1988                 CTR4(KTR_NET, "%20s: node [%x] (%p) queued writer can't "
 1989                     "proceed; queue flags 0x%lx", __func__, node->nd_ID, node,
 1990                     ngq->q_flags);
 1991                 return (NULL);
 1992         }
 1993 
 1994         /*
 1995          * Now we dequeue the request (whatever it may be) and correct the
 1996          * pending flags and the next and last pointers.
 1997          */
 1998         item = STAILQ_FIRST(&ngq->queue);
 1999         STAILQ_REMOVE_HEAD(&ngq->queue, el_next);
 2000         if (STAILQ_EMPTY(&ngq->queue))
 2001                 atomic_clear_int(&ngq->q_flags, OP_PENDING);
 2002         CTR6(KTR_NET, "%20s: node [%x] (%p) returning item %p as %s; queue "
 2003             "flags 0x%lx", __func__, node->nd_ID, node, item, *rw ? "WRITER" :
 2004             "READER", ngq->q_flags);
 2005         return (item);
 2006 }
 2007 
 2008 /*
 2009  * Queue a packet to be picked up later by someone else.
 2010  * If the queue could be run now, add node to the queue handler's worklist.
 2011  */
 2012 static __inline void
 2013 ng_queue_rw(node_p node, item_p  item, int rw)
 2014 {
 2015         struct ng_queue *ngq = &node->nd_input_queue;
 2016         if (rw == NGQRW_W)
 2017                 NGI_SET_WRITER(item);
 2018         else
 2019                 NGI_SET_READER(item);
 2020         item->depth = 1;
 2021 
 2022         NG_QUEUE_LOCK(ngq);
 2023         /* Set OP_PENDING flag and enqueue the item. */
 2024         atomic_set_int(&ngq->q_flags, OP_PENDING);
 2025         STAILQ_INSERT_TAIL(&ngq->queue, item, el_next);
 2026 
 2027         CTR5(KTR_NET, "%20s: node [%x] (%p) queued item %p as %s", __func__,
 2028             node->nd_ID, node, item, rw ? "WRITER" : "READER" );
 2029 
 2030         /*
 2031          * We can take the worklist lock with the node locked
 2032          * BUT NOT THE REVERSE!
 2033          */
 2034         if (NEXT_QUEUED_ITEM_CAN_PROCEED(ngq))
 2035                 ng_worklist_add(node);
 2036         NG_QUEUE_UNLOCK(ngq);
 2037 }
 2038 
 2039 /* Acquire reader lock on node. If node is busy, queue the packet. */
 2040 static __inline item_p
 2041 ng_acquire_read(node_p node, item_p item)
 2042 {
 2043         KASSERT(node != &ng_deadnode,
 2044             ("%s: working on deadnode", __func__));
 2045 
 2046         /* Reader needs node without writer and pending items. */
 2047         for (;;) {
 2048                 long t = node->nd_input_queue.q_flags;
 2049                 if (t & NGQ_RMASK)
 2050                         break; /* Node is not ready for reader. */
 2051                 if (atomic_cmpset_acq_int(&node->nd_input_queue.q_flags, t,
 2052                     t + READER_INCREMENT)) {
 2053                         /* Successfully grabbed node */
 2054                         CTR4(KTR_NET, "%20s: node [%x] (%p) acquired item %p",
 2055                             __func__, node->nd_ID, node, item);
 2056                         return (item);
 2057                 }
 2058                 cpu_spinwait();
 2059         }
 2060 
 2061         /* Queue the request for later. */
 2062         ng_queue_rw(node, item, NGQRW_R);
 2063 
 2064         return (NULL);
 2065 }
 2066 
 2067 /* Acquire writer lock on node. If node is busy, queue the packet. */
 2068 static __inline item_p
 2069 ng_acquire_write(node_p node, item_p item)
 2070 {
 2071         KASSERT(node != &ng_deadnode,
 2072             ("%s: working on deadnode", __func__));
 2073 
 2074         /* Writer needs completely idle node. */
 2075         if (atomic_cmpset_acq_int(&node->nd_input_queue.q_flags, 0,
 2076             WRITER_ACTIVE)) {
 2077                 /* Successfully grabbed node */
 2078                 CTR4(KTR_NET, "%20s: node [%x] (%p) acquired item %p",
 2079                     __func__, node->nd_ID, node, item);
 2080                 return (item);
 2081         }
 2082 
 2083         /* Queue the request for later. */
 2084         ng_queue_rw(node, item, NGQRW_W);
 2085 
 2086         return (NULL);
 2087 }
 2088 
 2089 #if 0
 2090 static __inline item_p
 2091 ng_upgrade_write(node_p node, item_p item)
 2092 {
 2093         struct ng_queue *ngq = &node->nd_input_queue;
 2094         KASSERT(node != &ng_deadnode,
 2095             ("%s: working on deadnode", __func__));
 2096 
 2097         NGI_SET_WRITER(item);
 2098 
 2099         NG_QUEUE_LOCK(ngq);
 2100 
 2101         /*
 2102          * There will never be no readers as we are there ourselves.
 2103          * Set the WRITER_ACTIVE flags ASAP to block out fast track readers.
 2104          * The caller we are running from will call ng_leave_read()
 2105          * soon, so we must account for that. We must leave again with the
 2106          * READER lock. If we find other readers, then
 2107          * queue the request for later. However "later" may be rignt now
 2108          * if there are no readers. We don't really care if there are queued
 2109          * items as we will bypass them anyhow.
 2110          */
 2111         atomic_add_int(&ngq->q_flags, WRITER_ACTIVE - READER_INCREMENT);
 2112         if ((ngq->q_flags & (NGQ_WMASK & ~OP_PENDING)) == WRITER_ACTIVE) {
 2113                 NG_QUEUE_UNLOCK(ngq);
 2114                 
 2115                 /* It's just us, act on the item. */
 2116                 /* will NOT drop writer lock when done */
 2117                 ng_apply_item(node, item, 0);
 2118 
 2119                 /*
 2120                  * Having acted on the item, atomically
 2121                  * downgrade back to READER and finish up.
 2122                  */
 2123                 atomic_add_int(&ngq->q_flags, READER_INCREMENT - WRITER_ACTIVE);
 2124 
 2125                 /* Our caller will call ng_leave_read() */
 2126                 return;
 2127         }
 2128         /*
 2129          * It's not just us active, so queue us AT THE HEAD.
 2130          * "Why?" I hear you ask.
 2131          * Put us at the head of the queue as we've already been
 2132          * through it once. If there is nothing else waiting,
 2133          * set the correct flags.
 2134          */
 2135         if (STAILQ_EMPTY(&ngq->queue)) {
 2136                 /* We've gone from, 0 to 1 item in the queue */
 2137                 atomic_set_int(&ngq->q_flags, OP_PENDING);
 2138 
 2139                 CTR3(KTR_NET, "%20s: node [%x] (%p) set OP_PENDING", __func__,
 2140                     node->nd_ID, node);
 2141         };
 2142         STAILQ_INSERT_HEAD(&ngq->queue, item, el_next);
 2143         CTR4(KTR_NET, "%20s: node [%x] (%p) requeued item %p as WRITER",
 2144             __func__, node->nd_ID, node, item );
 2145 
 2146         /* Reverse what we did above. That downgrades us back to reader */
 2147         atomic_add_int(&ngq->q_flags, READER_INCREMENT - WRITER_ACTIVE);
 2148         if (QUEUE_ACTIVE(ngq) && NEXT_QUEUED_ITEM_CAN_PROCEED(ngq))
 2149                 ng_worklist_add(node);
 2150         NG_QUEUE_UNLOCK(ngq);
 2151 
 2152         return;
 2153 }
 2154 #endif
 2155 
 2156 /* Release reader lock. */
 2157 static __inline void
 2158 ng_leave_read(node_p node)
 2159 {
 2160         atomic_subtract_rel_int(&node->nd_input_queue.q_flags, READER_INCREMENT);
 2161 }
 2162 
 2163 /* Release writer lock. */
 2164 static __inline void
 2165 ng_leave_write(node_p node)
 2166 {
 2167         atomic_clear_rel_int(&node->nd_input_queue.q_flags, WRITER_ACTIVE);
 2168 }
 2169 
 2170 /* Purge node queue. Called on node shutdown. */
 2171 static void
 2172 ng_flush_input_queue(node_p node)
 2173 {
 2174         struct ng_queue *ngq = &node->nd_input_queue;
 2175         item_p item;
 2176 
 2177         NG_QUEUE_LOCK(ngq);
 2178         while ((item = STAILQ_FIRST(&ngq->queue)) != NULL) {
 2179                 STAILQ_REMOVE_HEAD(&ngq->queue, el_next);
 2180                 if (STAILQ_EMPTY(&ngq->queue))
 2181                         atomic_clear_int(&ngq->q_flags, OP_PENDING);
 2182                 NG_QUEUE_UNLOCK(ngq);
 2183 
 2184                 /* If the item is supplying a callback, call it with an error */
 2185                 if (item->apply != NULL) {
 2186                         if (item->depth == 1)
 2187                                 item->apply->error = ENOENT;
 2188                         if (refcount_release(&item->apply->refs)) {
 2189                                 (*item->apply->apply)(item->apply->context,
 2190                                     item->apply->error);
 2191                         }
 2192                 }
 2193                 NG_FREE_ITEM(item);
 2194                 NG_QUEUE_LOCK(ngq);
 2195         }
 2196         NG_QUEUE_UNLOCK(ngq);
 2197 }
 2198 
 2199 /***********************************************************************
 2200 * Externally visible method for sending or queueing messages or data.
 2201 ***********************************************************************/
 2202 
 2203 /*
 2204  * The module code should have filled out the item correctly by this stage:
 2205  * Common:
 2206  *    reference to destination node.
 2207  *    Reference to destination rcv hook if relevant.
 2208  *    apply pointer must be or NULL or reference valid struct ng_apply_info.
 2209  * Data:
 2210  *    pointer to mbuf
 2211  * Control_Message:
 2212  *    pointer to msg.
 2213  *    ID of original sender node. (return address)
 2214  * Function:
 2215  *    Function pointer
 2216  *    void * argument
 2217  *    integer argument
 2218  *
 2219  * The nodes have several routines and macros to help with this task:
 2220  */
 2221 
 2222 int
 2223 ng_snd_item(item_p item, int flags)
 2224 {
 2225         hook_p hook;
 2226         node_p node;
 2227         int queue, rw;
 2228         struct ng_queue *ngq;
 2229         int error = 0;
 2230 
 2231         /* We are sending item, so it must be present! */
 2232         KASSERT(item != NULL, ("ng_snd_item: item is NULL"));
 2233 
 2234 #ifdef  NETGRAPH_DEBUG
 2235         _ngi_check(item, __FILE__, __LINE__);
 2236 #endif
 2237 
 2238         /* Item was sent once more, postpone apply() call. */
 2239         if (item->apply)
 2240                 refcount_acquire(&item->apply->refs);
 2241 
 2242         node = NGI_NODE(item);
 2243         /* Node is never optional. */
 2244         KASSERT(node != NULL, ("ng_snd_item: node is NULL"));
 2245 
 2246         hook = NGI_HOOK(item);
 2247         /* Valid hook and mbuf are mandatory for data. */
 2248         if ((item->el_flags & NGQF_TYPE) == NGQF_DATA) {
 2249                 KASSERT(hook != NULL, ("ng_snd_item: hook for data is NULL"));
 2250                 if (NGI_M(item) == NULL)
 2251                         ERROUT(EINVAL);
 2252                 CHECK_DATA_MBUF(NGI_M(item));
 2253         }
 2254 
 2255         /*
 2256          * If the item or the node specifies single threading, force
 2257          * writer semantics. Similarly, the node may say one hook always
 2258          * produces writers. These are overrides.
 2259          */
 2260         if (((item->el_flags & NGQF_RW) == NGQF_WRITER) ||
 2261             (node->nd_flags & NGF_FORCE_WRITER) ||
 2262             (hook && (hook->hk_flags & HK_FORCE_WRITER))) {
 2263                 rw = NGQRW_W;
 2264         } else {
 2265                 rw = NGQRW_R;
 2266         }
 2267 
 2268         /*
 2269          * If sender or receiver requests queued delivery, or call graph
 2270          * loops back from outbound to inbound path, or stack usage
 2271          * level is dangerous - enqueue message.
 2272          */
 2273         if ((flags & NG_QUEUE) || (hook && (hook->hk_flags & HK_QUEUE))) {
 2274                 queue = 1;
 2275         } else if (hook && (hook->hk_flags & HK_TO_INBOUND) &&
 2276             curthread->td_ng_outbound) {
 2277                 queue = 1;
 2278         } else {
 2279                 queue = 0;
 2280 #ifdef GET_STACK_USAGE
 2281                 /*
 2282                  * Most of netgraph nodes have small stack consumption and
 2283                  * for them 25% of free stack space is more than enough.
 2284                  * Nodes/hooks with higher stack usage should be marked as
 2285                  * HI_STACK. For them 50% of stack will be guaranteed then.
 2286                  * XXX: Values 25% and 50% are completely empirical.
 2287                  */
 2288                 size_t  st, su, sl;
 2289                 GET_STACK_USAGE(st, su);
 2290                 sl = st - su;
 2291                 if ((sl * 4 < st) || ((sl * 2 < st) &&
 2292                     ((node->nd_flags & NGF_HI_STACK) || (hook &&
 2293                     (hook->hk_flags & HK_HI_STACK)))))
 2294                         queue = 1;
 2295 #endif
 2296         }
 2297 
 2298         if (queue) {
 2299                 /* Put it on the queue for that node*/
 2300                 ng_queue_rw(node, item, rw);
 2301                 return ((flags & NG_PROGRESS) ? EINPROGRESS : 0);
 2302         }
 2303 
 2304         /*
 2305          * We already decided how we will be queueud or treated.
 2306          * Try get the appropriate operating permission.
 2307          */
 2308         if (rw == NGQRW_R)
 2309                 item = ng_acquire_read(node, item);
 2310         else
 2311                 item = ng_acquire_write(node, item);
 2312 
 2313         /* Item was queued while trying to get permission. */
 2314         if (item == NULL)
 2315                 return ((flags & NG_PROGRESS) ? EINPROGRESS : 0);
 2316 
 2317         NGI_GET_NODE(item, node); /* zaps stored node */
 2318 
 2319         item->depth++;
 2320         error = ng_apply_item(node, item, rw); /* drops r/w lock when done */
 2321 
 2322         /* If something is waiting on queue and ready, schedule it. */
 2323         ngq = &node->nd_input_queue;
 2324         if (QUEUE_ACTIVE(ngq)) {
 2325                 NG_QUEUE_LOCK(ngq);
 2326                 if (QUEUE_ACTIVE(ngq) && NEXT_QUEUED_ITEM_CAN_PROCEED(ngq))
 2327                         ng_worklist_add(node);
 2328                 NG_QUEUE_UNLOCK(ngq);
 2329         }
 2330 
 2331         /*
 2332          * Node may go away as soon as we remove the reference.
 2333          * Whatever we do, DO NOT access the node again!
 2334          */
 2335         NG_NODE_UNREF(node);
 2336 
 2337         return (error);
 2338 
 2339 done:
 2340         /* If was not sent, apply callback here. */
 2341         if (item->apply != NULL) {
 2342                 if (item->depth == 0 && error != 0)
 2343                         item->apply->error = error;
 2344                 if (refcount_release(&item->apply->refs)) {
 2345                         (*item->apply->apply)(item->apply->context,
 2346                             item->apply->error);
 2347                 }
 2348         }
 2349 
 2350         NG_FREE_ITEM(item);
 2351         return (error);
 2352 }
 2353 
 2354 /*
 2355  * We have an item that was possibly queued somewhere.
 2356  * It should contain all the information needed
 2357  * to run it on the appropriate node/hook.
 2358  * If there is apply pointer and we own the last reference, call apply().
 2359  */
 2360 static int
 2361 ng_apply_item(node_p node, item_p item, int rw)
 2362 {
 2363         hook_p  hook;
 2364         ng_rcvdata_t *rcvdata;
 2365         ng_rcvmsg_t *rcvmsg;
 2366         struct ng_apply_info *apply;
 2367         int     error = 0, depth;
 2368 
 2369         /* Node and item are never optional. */
 2370         KASSERT(node != NULL, ("ng_apply_item: node is NULL"));
 2371         KASSERT(item != NULL, ("ng_apply_item: item is NULL"));
 2372 
 2373         NGI_GET_HOOK(item, hook); /* clears stored hook */
 2374 #ifdef  NETGRAPH_DEBUG
 2375         _ngi_check(item, __FILE__, __LINE__);
 2376 #endif
 2377 
 2378         apply = item->apply;
 2379         depth = item->depth;
 2380 
 2381         switch (item->el_flags & NGQF_TYPE) {
 2382         case NGQF_DATA:
 2383                 /*
 2384                  * Check things are still ok as when we were queued.
 2385                  */
 2386                 KASSERT(hook != NULL, ("ng_apply_item: hook for data is NULL"));
 2387                 if (NG_HOOK_NOT_VALID(hook) ||
 2388                     NG_NODE_NOT_VALID(node)) {
 2389                         error = EIO;
 2390                         NG_FREE_ITEM(item);
 2391                         break;
 2392                 }
 2393                 /*
 2394                  * If no receive method, just silently drop it.
 2395                  * Give preference to the hook over-ride method.
 2396                  */
 2397                 if ((!(rcvdata = hook->hk_rcvdata)) &&
 2398                     (!(rcvdata = NG_HOOK_NODE(hook)->nd_type->rcvdata))) {
 2399                         error = 0;
 2400                         NG_FREE_ITEM(item);
 2401                         break;
 2402                 }
 2403                 error = (*rcvdata)(hook, item);
 2404                 break;
 2405         case NGQF_MESG:
 2406                 if (hook && NG_HOOK_NOT_VALID(hook)) {
 2407                         /*
 2408                          * The hook has been zapped then we can't use it.
 2409                          * Immediately drop its reference.
 2410                          * The message may not need it.
 2411                          */
 2412                         NG_HOOK_UNREF(hook);
 2413                         hook = NULL;
 2414                 }
 2415                 /*
 2416                  * Similarly, if the node is a zombie there is
 2417                  * nothing we can do with it, drop everything.
 2418                  */
 2419                 if (NG_NODE_NOT_VALID(node)) {
 2420                         TRAP_ERROR();
 2421                         error = EINVAL;
 2422                         NG_FREE_ITEM(item);
 2423                         break;
 2424                 }
 2425                 /*
 2426                  * Call the appropriate message handler for the object.
 2427                  * It is up to the message handler to free the message.
 2428                  * If it's a generic message, handle it generically,
 2429                  * otherwise call the type's message handler (if it exists).
 2430                  * XXX (race). Remember that a queued message may
 2431                  * reference a node or hook that has just been
 2432                  * invalidated. It will exist as the queue code
 2433                  * is holding a reference, but..
 2434                  */
 2435                 if ((NGI_MSG(item)->header.typecookie == NGM_GENERIC_COOKIE) &&
 2436                     ((NGI_MSG(item)->header.flags & NGF_RESP) == 0)) {
 2437                         error = ng_generic_msg(node, item, hook);
 2438                         break;
 2439                 }
 2440                 if (((!hook) || (!(rcvmsg = hook->hk_rcvmsg))) &&
 2441                     (!(rcvmsg = node->nd_type->rcvmsg))) {
 2442                         TRAP_ERROR();
 2443                         error = 0;
 2444                         NG_FREE_ITEM(item);
 2445                         break;
 2446                 }
 2447                 error = (*rcvmsg)(node, item, hook);
 2448                 break;
 2449         case NGQF_FN:
 2450         case NGQF_FN2:
 2451                 /*
 2452                  * In the case of the shutdown message we allow it to hit
 2453                  * even if the node is invalid.
 2454                  */
 2455                 if (NG_NODE_NOT_VALID(node) &&
 2456                     NGI_FN(item) != &ng_rmnode) {
 2457                         TRAP_ERROR();
 2458                         error = EINVAL;
 2459                         NG_FREE_ITEM(item);
 2460                         break;
 2461                 }
 2462                 /* Same is about some internal functions and invalid hook. */
 2463                 if (hook && NG_HOOK_NOT_VALID(hook) &&
 2464                     NGI_FN2(item) != &ng_con_part2 &&
 2465                     NGI_FN2(item) != &ng_con_part3 &&
 2466                     NGI_FN(item) != &ng_rmhook_part2) {
 2467                         TRAP_ERROR();
 2468                         error = EINVAL;
 2469                         NG_FREE_ITEM(item);
 2470                         break;
 2471                 }
 2472                 
 2473                 if ((item->el_flags & NGQF_TYPE) == NGQF_FN) {
 2474                         (*NGI_FN(item))(node, hook, NGI_ARG1(item),
 2475                             NGI_ARG2(item));
 2476                         NG_FREE_ITEM(item);
 2477                 } else  /* it is NGQF_FN2 */
 2478                         error = (*NGI_FN2(item))(node, item, hook);
 2479                 break;
 2480         }
 2481         /*
 2482          * We held references on some of the resources
 2483          * that we took from the item. Now that we have
 2484          * finished doing everything, drop those references.
 2485          */
 2486         if (hook)
 2487                 NG_HOOK_UNREF(hook);
 2488 
 2489         if (rw == NGQRW_R)
 2490                 ng_leave_read(node);
 2491         else
 2492                 ng_leave_write(node);
 2493 
 2494         /* Apply callback. */
 2495         if (apply != NULL) {
 2496                 if (depth == 1 && error != 0)
 2497                         apply->error = error;
 2498                 if (refcount_release(&apply->refs))
 2499                         (*apply->apply)(apply->context, apply->error);
 2500         }
 2501 
 2502         return (error);
 2503 }
 2504 
 2505 /***********************************************************************
 2506  * Implement the 'generic' control messages
 2507  ***********************************************************************/
 2508 static int
 2509 ng_generic_msg(node_p here, item_p item, hook_p lasthook)
 2510 {
 2511         int error = 0;
 2512         struct ng_mesg *msg;
 2513         struct ng_mesg *resp = NULL;
 2514 
 2515         NGI_GET_MSG(item, msg);
 2516         if (msg->header.typecookie != NGM_GENERIC_COOKIE) {
 2517                 TRAP_ERROR();
 2518                 error = EINVAL;
 2519                 goto out;
 2520         }
 2521         switch (msg->header.cmd) {
 2522         case NGM_SHUTDOWN:
 2523                 ng_rmnode(here, NULL, NULL, 0);
 2524                 break;
 2525         case NGM_MKPEER:
 2526             {
 2527                 struct ngm_mkpeer *const mkp = (struct ngm_mkpeer *) msg->data;
 2528 
 2529                 if (msg->header.arglen != sizeof(*mkp)) {
 2530                         TRAP_ERROR();
 2531                         error = EINVAL;
 2532                         break;
 2533                 }
 2534                 mkp->type[sizeof(mkp->type) - 1] = '\0';
 2535                 mkp->ourhook[sizeof(mkp->ourhook) - 1] = '\0';
 2536                 mkp->peerhook[sizeof(mkp->peerhook) - 1] = '\0';
 2537                 error = ng_mkpeer(here, mkp->ourhook, mkp->peerhook, mkp->type);
 2538                 break;
 2539             }
 2540         case NGM_CONNECT:
 2541             {
 2542                 struct ngm_connect *const con =
 2543                         (struct ngm_connect *) msg->data;
 2544                 node_p node2;
 2545 
 2546                 if (msg->header.arglen != sizeof(*con)) {
 2547                         TRAP_ERROR();
 2548                         error = EINVAL;
 2549                         break;
 2550                 }
 2551                 con->path[sizeof(con->path) - 1] = '\0';
 2552                 con->ourhook[sizeof(con->ourhook) - 1] = '\0';
 2553                 con->peerhook[sizeof(con->peerhook) - 1] = '\0';
 2554                 /* Don't forget we get a reference.. */
 2555                 error = ng_path2noderef(here, con->path, &node2, NULL);
 2556                 if (error)
 2557                         break;
 2558                 error = ng_con_nodes(item, here, con->ourhook,
 2559                     node2, con->peerhook);
 2560                 NG_NODE_UNREF(node2);
 2561                 break;
 2562             }
 2563         case NGM_NAME:
 2564             {
 2565                 struct ngm_name *const nam = (struct ngm_name *) msg->data;
 2566 
 2567                 if (msg->header.arglen != sizeof(*nam)) {
 2568                         TRAP_ERROR();
 2569                         error = EINVAL;
 2570                         break;
 2571                 }
 2572                 nam->name[sizeof(nam->name) - 1] = '\0';
 2573                 error = ng_name_node(here, nam->name);
 2574                 break;
 2575             }
 2576         case NGM_RMHOOK:
 2577             {
 2578                 struct ngm_rmhook *const rmh = (struct ngm_rmhook *) msg->data;
 2579                 hook_p hook;
 2580 
 2581                 if (msg->header.arglen != sizeof(*rmh)) {
 2582                         TRAP_ERROR();
 2583                         error = EINVAL;
 2584                         break;
 2585                 }
 2586                 rmh->ourhook[sizeof(rmh->ourhook) - 1] = '\0';
 2587                 if ((hook = ng_findhook(here, rmh->ourhook)) != NULL)
 2588                         ng_destroy_hook(hook);
 2589                 break;
 2590             }
 2591         case NGM_NODEINFO:
 2592             {
 2593                 struct nodeinfo *ni;
 2594 
 2595                 NG_MKRESPONSE(resp, msg, sizeof(*ni), M_NOWAIT);
 2596                 if (resp == NULL) {
 2597                         error = ENOMEM;
 2598                         break;
 2599                 }
 2600 
 2601                 /* Fill in node info */
 2602                 ni = (struct nodeinfo *) resp->data;
 2603                 if (NG_NODE_HAS_NAME(here))
 2604                         strcpy(ni->name, NG_NODE_NAME(here));
 2605                 strcpy(ni->type, here->nd_type->name);
 2606                 ni->id = ng_node2ID(here);
 2607                 ni->hooks = here->nd_numhooks;
 2608                 break;
 2609             }
 2610         case NGM_LISTHOOKS:
 2611             {
 2612                 const int nhooks = here->nd_numhooks;
 2613                 struct hooklist *hl;
 2614                 struct nodeinfo *ni;
 2615                 hook_p hook;
 2616 
 2617                 /* Get response struct */
 2618                 NG_MKRESPONSE(resp, msg, sizeof(*hl) +
 2619                     (nhooks * sizeof(struct linkinfo)), M_NOWAIT);
 2620                 if (resp == NULL) {
 2621                         error = ENOMEM;
 2622                         break;
 2623                 }
 2624                 hl = (struct hooklist *) resp->data;
 2625                 ni = &hl->nodeinfo;
 2626 
 2627                 /* Fill in node info */
 2628                 if (NG_NODE_HAS_NAME(here))
 2629                         strcpy(ni->name, NG_NODE_NAME(here));
 2630                 strcpy(ni->type, here->nd_type->name);
 2631                 ni->id = ng_node2ID(here);
 2632 
 2633                 /* Cycle through the linked list of hooks */
 2634                 ni->hooks = 0;
 2635                 LIST_FOREACH(hook, &here->nd_hooks, hk_hooks) {
 2636                         struct linkinfo *const link = &hl->link[ni->hooks];
 2637 
 2638                         if (ni->hooks >= nhooks) {
 2639                                 log(LOG_ERR, "%s: number of %s changed\n",
 2640                                     __func__, "hooks");
 2641                                 break;
 2642                         }
 2643                         if (NG_HOOK_NOT_VALID(hook))
 2644                                 continue;
 2645                         strcpy(link->ourhook, NG_HOOK_NAME(hook));
 2646                         strcpy(link->peerhook, NG_PEER_HOOK_NAME(hook));
 2647                         if (NG_PEER_NODE_NAME(hook)[0] != '\0')
 2648                                 strcpy(link->nodeinfo.name,
 2649                                     NG_PEER_NODE_NAME(hook));
 2650                         strcpy(link->nodeinfo.type,
 2651                            NG_PEER_NODE(hook)->nd_type->name);
 2652                         link->nodeinfo.id = ng_node2ID(NG_PEER_NODE(hook));
 2653                         link->nodeinfo.hooks = NG_PEER_NODE(hook)->nd_numhooks;
 2654                         ni->hooks++;
 2655                 }
 2656                 break;
 2657             }
 2658 
 2659         case NGM_LISTNODES:
 2660             {
 2661                 struct namelist *nl;
 2662                 node_p node;
 2663                 int i;
 2664 
 2665                 IDHASH_RLOCK();
 2666                 /* Get response struct. */
 2667                 NG_MKRESPONSE(resp, msg, sizeof(*nl) +
 2668                     (V_ng_nodes * sizeof(struct nodeinfo)), M_NOWAIT | M_ZERO);
 2669                 if (resp == NULL) {
 2670                         IDHASH_RUNLOCK();
 2671                         error = ENOMEM;
 2672                         break;
 2673                 }
 2674                 nl = (struct namelist *) resp->data;
 2675 
 2676                 /* Cycle through the lists of nodes. */
 2677                 nl->numnames = 0;
 2678                 for (i = 0; i <= V_ng_ID_hmask; i++) {
 2679                         LIST_FOREACH(node, &V_ng_ID_hash[i], nd_idnodes) {
 2680                                 struct nodeinfo *const np =
 2681                                     &nl->nodeinfo[nl->numnames];
 2682 
 2683                                 if (NG_NODE_NOT_VALID(node))
 2684                                         continue;
 2685                                 if (NG_NODE_HAS_NAME(node))
 2686                                         strcpy(np->name, NG_NODE_NAME(node));
 2687                                 strcpy(np->type, node->nd_type->name);
 2688                                 np->id = ng_node2ID(node);
 2689                                 np->hooks = node->nd_numhooks;
 2690                                 KASSERT(nl->numnames < V_ng_nodes,
 2691                                     ("%s: no space", __func__));
 2692                                 nl->numnames++;
 2693                         }
 2694                 }
 2695                 IDHASH_RUNLOCK();
 2696                 break;
 2697             }
 2698         case NGM_LISTNAMES:
 2699             {
 2700                 struct namelist *nl;
 2701                 node_p node;
 2702                 int i;
 2703 
 2704                 NAMEHASH_RLOCK();
 2705                 /* Get response struct. */
 2706                 NG_MKRESPONSE(resp, msg, sizeof(*nl) +
 2707                     (V_ng_named_nodes * sizeof(struct nodeinfo)), M_NOWAIT);
 2708                 if (resp == NULL) {
 2709                         NAMEHASH_RUNLOCK();
 2710                         error = ENOMEM;
 2711                         break;
 2712                 }
 2713                 nl = (struct namelist *) resp->data;
 2714 
 2715                 /* Cycle through the lists of nodes. */
 2716                 nl->numnames = 0;
 2717                 for (i = 0; i <= V_ng_name_hmask; i++) {
 2718                         LIST_FOREACH(node, &V_ng_name_hash[i], nd_nodes) {
 2719                                 struct nodeinfo *const np =
 2720                                     &nl->nodeinfo[nl->numnames];
 2721 
 2722                                 if (NG_NODE_NOT_VALID(node))
 2723                                         continue;
 2724                                 strcpy(np->name, NG_NODE_NAME(node));
 2725                                 strcpy(np->type, node->nd_type->name);
 2726                                 np->id = ng_node2ID(node);
 2727                                 np->hooks = node->nd_numhooks;
 2728                                 KASSERT(nl->numnames < V_ng_named_nodes,
 2729                                     ("%s: no space", __func__));
 2730                                 nl->numnames++;
 2731                         }
 2732                 }
 2733                 NAMEHASH_RUNLOCK();
 2734                 break;
 2735             }
 2736 
 2737         case NGM_LISTTYPES:
 2738             {
 2739                 struct typelist *tl;
 2740                 struct ng_type *type;
 2741                 int num = 0;
 2742 
 2743                 TYPELIST_RLOCK();
 2744                 /* Count number of types */
 2745                 LIST_FOREACH(type, &ng_typelist, types)
 2746                         num++;
 2747 
 2748                 /* Get response struct */
 2749                 NG_MKRESPONSE(resp, msg, sizeof(*tl) +
 2750                     (num * sizeof(struct typeinfo)), M_NOWAIT);
 2751                 if (resp == NULL) {
 2752                         TYPELIST_RUNLOCK();
 2753                         error = ENOMEM;
 2754                         break;
 2755                 }
 2756                 tl = (struct typelist *) resp->data;
 2757 
 2758                 /* Cycle through the linked list of types */
 2759                 tl->numtypes = 0;
 2760                 LIST_FOREACH(type, &ng_typelist, types) {
 2761                         struct typeinfo *const tp = &tl->typeinfo[tl->numtypes];
 2762 
 2763                         strcpy(tp->type_name, type->name);
 2764                         tp->numnodes = type->refs - 1; /* don't count list */
 2765                         KASSERT(tl->numtypes < num, ("%s: no space", __func__));
 2766                         tl->numtypes++;
 2767                 }
 2768                 TYPELIST_RUNLOCK();
 2769                 break;
 2770             }
 2771 
 2772         case NGM_BINARY2ASCII:
 2773             {
 2774                 int bufSize = 20 * 1024;        /* XXX hard coded constant */
 2775                 const struct ng_parse_type *argstype;
 2776                 const struct ng_cmdlist *c;
 2777                 struct ng_mesg *binary, *ascii;
 2778 
 2779                 /* Data area must contain a valid netgraph message */
 2780                 binary = (struct ng_mesg *)msg->data;
 2781                 if (msg->header.arglen < sizeof(struct ng_mesg) ||
 2782                     (msg->header.arglen - sizeof(struct ng_mesg) <
 2783                     binary->header.arglen)) {
 2784                         TRAP_ERROR();
 2785                         error = EINVAL;
 2786                         break;
 2787                 }
 2788 
 2789                 /* Get a response message with lots of room */
 2790                 NG_MKRESPONSE(resp, msg, sizeof(*ascii) + bufSize, M_NOWAIT);
 2791                 if (resp == NULL) {
 2792                         error = ENOMEM;
 2793                         break;
 2794                 }
 2795                 ascii = (struct ng_mesg *)resp->data;
 2796 
 2797                 /* Copy binary message header to response message payload */
 2798                 bcopy(binary, ascii, sizeof(*binary));
 2799 
 2800                 /* Find command by matching typecookie and command number */
 2801                 for (c = here->nd_type->cmdlist; c != NULL && c->name != NULL;
 2802                     c++) {
 2803                         if (binary->header.typecookie == c->cookie &&
 2804                             binary->header.cmd == c->cmd)
 2805                                 break;
 2806                 }
 2807                 if (c == NULL || c->name == NULL) {
 2808                         for (c = ng_generic_cmds; c->name != NULL; c++) {
 2809                                 if (binary->header.typecookie == c->cookie &&
 2810                                     binary->header.cmd == c->cmd)
 2811                                         break;
 2812                         }
 2813                         if (c->name == NULL) {
 2814                                 NG_FREE_MSG(resp);
 2815                                 error = ENOSYS;
 2816                                 break;
 2817                         }
 2818                 }
 2819 
 2820                 /* Convert command name to ASCII */
 2821                 snprintf(ascii->header.cmdstr, sizeof(ascii->header.cmdstr),
 2822                     "%s", c->name);
 2823 
 2824                 /* Convert command arguments to ASCII */
 2825                 argstype = (binary->header.flags & NGF_RESP) ?
 2826                     c->respType : c->mesgType;
 2827                 if (argstype == NULL) {
 2828                         *ascii->data = '\0';
 2829                 } else {
 2830                         if ((error = ng_unparse(argstype,
 2831                             (u_char *)binary->data,
 2832                             ascii->data, bufSize)) != 0) {
 2833                                 NG_FREE_MSG(resp);
 2834                                 break;
 2835                         }
 2836                 }
 2837 
 2838                 /* Return the result as struct ng_mesg plus ASCII string */
 2839                 bufSize = strlen(ascii->data) + 1;
 2840                 ascii->header.arglen = bufSize;
 2841                 resp->header.arglen = sizeof(*ascii) + bufSize;
 2842                 break;
 2843             }
 2844 
 2845         case NGM_ASCII2BINARY:
 2846             {
 2847                 int bufSize = 20 * 1024;        /* XXX hard coded constant */
 2848                 const struct ng_cmdlist *c;
 2849                 const struct ng_parse_type *argstype;
 2850                 struct ng_mesg *ascii, *binary;
 2851                 int off = 0;
 2852 
 2853                 /* Data area must contain at least a struct ng_mesg + '\0' */
 2854                 ascii = (struct ng_mesg *)msg->data;
 2855                 if ((msg->header.arglen < sizeof(*ascii) + 1) ||
 2856                     (ascii->header.arglen < 1) ||
 2857                     (msg->header.arglen < sizeof(*ascii) +
 2858                     ascii->header.arglen)) {
 2859                         TRAP_ERROR();
 2860                         error = EINVAL;
 2861                         break;
 2862                 }
 2863                 ascii->data[ascii->header.arglen - 1] = '\0';
 2864 
 2865                 /* Get a response message with lots of room */
 2866                 NG_MKRESPONSE(resp, msg, sizeof(*binary) + bufSize, M_NOWAIT);
 2867                 if (resp == NULL) {
 2868                         error = ENOMEM;
 2869                         break;
 2870                 }
 2871                 binary = (struct ng_mesg *)resp->data;
 2872 
 2873                 /* Copy ASCII message header to response message payload */
 2874                 bcopy(ascii, binary, sizeof(*ascii));
 2875 
 2876                 /* Find command by matching ASCII command string */
 2877                 for (c = here->nd_type->cmdlist;
 2878                     c != NULL && c->name != NULL; c++) {
 2879                         if (strcmp(ascii->header.cmdstr, c->name) == 0)
 2880                                 break;
 2881                 }
 2882                 if (c == NULL || c->name == NULL) {
 2883                         for (c = ng_generic_cmds; c->name != NULL; c++) {
 2884                                 if (strcmp(ascii->header.cmdstr, c->name) == 0)
 2885                                         break;
 2886                         }
 2887                         if (c->name == NULL) {
 2888                                 NG_FREE_MSG(resp);
 2889                                 error = ENOSYS;
 2890                                 break;
 2891                         }
 2892                 }
 2893 
 2894                 /* Convert command name to binary */
 2895                 binary->header.cmd = c->cmd;
 2896                 binary->header.typecookie = c->cookie;
 2897 
 2898                 /* Convert command arguments to binary */
 2899                 argstype = (binary->header.flags & NGF_RESP) ?
 2900                     c->respType : c->mesgType;
 2901                 if (argstype == NULL) {
 2902                         bufSize = 0;
 2903                 } else {
 2904                         if ((error = ng_parse(argstype, ascii->data, &off,
 2905                             (u_char *)binary->data, &bufSize)) != 0) {
 2906                                 NG_FREE_MSG(resp);
 2907                                 break;
 2908                         }
 2909                 }
 2910 
 2911                 /* Return the result */
 2912                 binary->header.arglen = bufSize;
 2913                 resp->header.arglen = sizeof(*binary) + bufSize;
 2914                 break;
 2915             }
 2916 
 2917         case NGM_TEXT_CONFIG:
 2918         case NGM_TEXT_STATUS:
 2919                 /*
 2920                  * This one is tricky as it passes the command down to the
 2921                  * actual node, even though it is a generic type command.
 2922                  * This means we must assume that the item/msg is already freed
 2923                  * when control passes back to us.
 2924                  */
 2925                 if (here->nd_type->rcvmsg != NULL) {
 2926                         NGI_MSG(item) = msg; /* put it back as we found it */
 2927                         return((*here->nd_type->rcvmsg)(here, item, lasthook));
 2928                 }
 2929                 /* Fall through if rcvmsg not supported */
 2930         default:
 2931                 TRAP_ERROR();
 2932                 error = EINVAL;
 2933         }
 2934         /*
 2935          * Sometimes a generic message may be statically allocated
 2936          * to avoid problems with allocating when in tight memory situations.
 2937          * Don't free it if it is so.
 2938          * I break them apart here, because erros may cause a free if the item
 2939          * in which case we'd be doing it twice.
 2940          * they are kept together above, to simplify freeing.
 2941          */
 2942 out:
 2943         NG_RESPOND_MSG(error, here, item, resp);
 2944         NG_FREE_MSG(msg);
 2945         return (error);
 2946 }
 2947 
 2948 /************************************************************************
 2949                         Queue element get/free routines
 2950 ************************************************************************/
 2951 
 2952 uma_zone_t                      ng_qzone;
 2953 uma_zone_t                      ng_qdzone;
 2954 static int                      numthreads = 0; /* number of queue threads */
 2955 static int                      maxalloc = 4096;/* limit the damage of a leak */
 2956 static int                      maxdata = 4096; /* limit the damage of a DoS */
 2957 
 2958 SYSCTL_INT(_net_graph, OID_AUTO, threads, CTLFLAG_RDTUN, &numthreads,
 2959     0, "Number of queue processing threads");
 2960 SYSCTL_INT(_net_graph, OID_AUTO, maxalloc, CTLFLAG_RDTUN, &maxalloc,
 2961     0, "Maximum number of non-data queue items to allocate");
 2962 SYSCTL_INT(_net_graph, OID_AUTO, maxdata, CTLFLAG_RDTUN, &maxdata,
 2963     0, "Maximum number of data queue items to allocate");
 2964 
 2965 #ifdef  NETGRAPH_DEBUG
 2966 static TAILQ_HEAD(, ng_item) ng_itemlist = TAILQ_HEAD_INITIALIZER(ng_itemlist);
 2967 static int allocated;   /* number of items malloc'd */
 2968 #endif
 2969 
 2970 /*
 2971  * Get a queue entry.
 2972  * This is usually called when a packet first enters netgraph.
 2973  * By definition, this is usually from an interrupt, or from a user.
 2974  * Users are not so important, but try be quick for the times that it's
 2975  * an interrupt.
 2976  */
 2977 static __inline item_p
 2978 ng_alloc_item(int type, int flags)
 2979 {
 2980         item_p item;
 2981 
 2982         KASSERT(((type & ~NGQF_TYPE) == 0),
 2983             ("%s: incorrect item type: %d", __func__, type));
 2984 
 2985         item = uma_zalloc((type == NGQF_DATA) ? ng_qdzone : ng_qzone,
 2986             ((flags & NG_WAITOK) ? M_WAITOK : M_NOWAIT) | M_ZERO);
 2987 
 2988         if (item) {
 2989                 item->el_flags = type;
 2990 #ifdef  NETGRAPH_DEBUG
 2991                 mtx_lock(&ngq_mtx);
 2992                 TAILQ_INSERT_TAIL(&ng_itemlist, item, all);
 2993                 allocated++;
 2994                 mtx_unlock(&ngq_mtx);
 2995 #endif
 2996         }
 2997 
 2998         return (item);
 2999 }
 3000 
 3001 /*
 3002  * Release a queue entry
 3003  */
 3004 void
 3005 ng_free_item(item_p item)
 3006 {
 3007         /*
 3008          * The item may hold resources on it's own. We need to free
 3009          * these before we can free the item. What they are depends upon
 3010          * what kind of item it is. it is important that nodes zero
 3011          * out pointers to resources that they remove from the item
 3012          * or we release them again here.
 3013          */
 3014         switch (item->el_flags & NGQF_TYPE) {
 3015         case NGQF_DATA:
 3016                 /* If we have an mbuf still attached.. */
 3017                 NG_FREE_M(_NGI_M(item));
 3018                 break;
 3019         case NGQF_MESG:
 3020                 _NGI_RETADDR(item) = 0;
 3021                 NG_FREE_MSG(_NGI_MSG(item));
 3022                 break;
 3023         case NGQF_FN:
 3024         case NGQF_FN2:
 3025                 /* nothing to free really, */
 3026                 _NGI_FN(item) = NULL;
 3027                 _NGI_ARG1(item) = NULL;
 3028                 _NGI_ARG2(item) = 0;
 3029                 break;
 3030         }
 3031         /* If we still have a node or hook referenced... */
 3032         _NGI_CLR_NODE(item);
 3033         _NGI_CLR_HOOK(item);
 3034 
 3035 #ifdef  NETGRAPH_DEBUG
 3036         mtx_lock(&ngq_mtx);
 3037         TAILQ_REMOVE(&ng_itemlist, item, all);
 3038         allocated--;
 3039         mtx_unlock(&ngq_mtx);
 3040 #endif
 3041         uma_zfree(((item->el_flags & NGQF_TYPE) == NGQF_DATA) ?
 3042             ng_qdzone : ng_qzone, item);
 3043 }
 3044 
 3045 /*
 3046  * Change type of the queue entry.
 3047  * Possibly reallocates it from another UMA zone.
 3048  */
 3049 static __inline item_p
 3050 ng_realloc_item(item_p pitem, int type, int flags)
 3051 {
 3052         item_p item;
 3053         int from, to;
 3054 
 3055         KASSERT((pitem != NULL), ("%s: can't reallocate NULL", __func__));
 3056         KASSERT(((type & ~NGQF_TYPE) == 0),
 3057             ("%s: incorrect item type: %d", __func__, type));
 3058 
 3059         from = ((pitem->el_flags & NGQF_TYPE) == NGQF_DATA);
 3060         to = (type == NGQF_DATA);
 3061         if (from != to) {
 3062                 /* If reallocation is required do it and copy item. */
 3063                 if ((item = ng_alloc_item(type, flags)) == NULL) {
 3064                         ng_free_item(pitem);
 3065                         return (NULL);
 3066                 }
 3067                 *item = *pitem;
 3068                 ng_free_item(pitem);
 3069         } else
 3070                 item = pitem;
 3071         item->el_flags = (item->el_flags & ~NGQF_TYPE) | type;
 3072 
 3073         return (item);
 3074 }
 3075 
 3076 /************************************************************************
 3077                         Module routines
 3078 ************************************************************************/
 3079 
 3080 /*
 3081  * Handle the loading/unloading of a netgraph node type module
 3082  */
 3083 int
 3084 ng_mod_event(module_t mod, int event, void *data)
 3085 {
 3086         struct ng_type *const type = data;
 3087         int error = 0;
 3088 
 3089         switch (event) {
 3090         case MOD_LOAD:
 3091 
 3092                 /* Register new netgraph node type */
 3093                 if ((error = ng_newtype(type)) != 0)
 3094                         break;
 3095 
 3096                 /* Call type specific code */
 3097                 if (type->mod_event != NULL)
 3098                         if ((error = (*type->mod_event)(mod, event, data))) {
 3099                                 TYPELIST_WLOCK();
 3100                                 type->refs--;   /* undo it */
 3101                                 LIST_REMOVE(type, types);
 3102                                 TYPELIST_WUNLOCK();
 3103                         }
 3104                 break;
 3105 
 3106         case MOD_UNLOAD:
 3107                 if (type->refs > 1) {           /* make sure no nodes exist! */
 3108                         error = EBUSY;
 3109                 } else {
 3110                         if (type->refs == 0) /* failed load, nothing to undo */
 3111                                 break;
 3112                         if (type->mod_event != NULL) {  /* check with type */
 3113                                 error = (*type->mod_event)(mod, event, data);
 3114                                 if (error != 0) /* type refuses.. */
 3115                                         break;
 3116                         }
 3117                         TYPELIST_WLOCK();
 3118                         LIST_REMOVE(type, types);
 3119                         TYPELIST_WUNLOCK();
 3120                 }
 3121                 break;
 3122 
 3123         default:
 3124                 if (type->mod_event != NULL)
 3125                         error = (*type->mod_event)(mod, event, data);
 3126                 else
 3127                         error = EOPNOTSUPP;             /* XXX ? */
 3128                 break;
 3129         }
 3130         return (error);
 3131 }
 3132 
 3133 static void
 3134 vnet_netgraph_init(const void *unused __unused)
 3135 {
 3136 
 3137         /* We start with small hashes, but they can grow. */
 3138         V_ng_ID_hash = hashinit(16, M_NETGRAPH_NODE, &V_ng_ID_hmask);
 3139         V_ng_name_hash = hashinit(16, M_NETGRAPH_NODE, &V_ng_name_hmask);
 3140 }
 3141 VNET_SYSINIT(vnet_netgraph_init, SI_SUB_NETGRAPH, SI_ORDER_FIRST,
 3142     vnet_netgraph_init, NULL);
 3143 
 3144 #ifdef VIMAGE
 3145 static void
 3146 vnet_netgraph_uninit(const void *unused __unused)
 3147 {
 3148         node_p node = NULL, last_killed = NULL;
 3149         int i;
 3150 
 3151         do {
 3152                 /* Find a node to kill */
 3153                 IDHASH_RLOCK();
 3154                 for (i = 0; i <= V_ng_ID_hmask; i++) {
 3155                         LIST_FOREACH(node, &V_ng_ID_hash[i], nd_idnodes) {
 3156                                 if (node != &ng_deadnode) {
 3157                                         NG_NODE_REF(node);
 3158                                         break;
 3159                                 }
 3160                         }
 3161                         if (node != NULL)
 3162                                 break;
 3163                 }
 3164                 IDHASH_RUNLOCK();
 3165 
 3166                 /* Attempt to kill it only if it is a regular node */
 3167                 if (node != NULL) {
 3168                         if (node == last_killed) {
 3169                                 /* This should never happen */
 3170                                 printf("ng node %s needs NGF_REALLY_DIE\n",
 3171                                     node->nd_name);
 3172                                 if (node->nd_flags & NGF_REALLY_DIE)
 3173                                         panic("ng node %s won't die",
 3174                                             node->nd_name);
 3175                                 node->nd_flags |= NGF_REALLY_DIE;
 3176                         }
 3177                         ng_rmnode(node, NULL, NULL, 0);
 3178                         NG_NODE_UNREF(node);
 3179                         last_killed = node;
 3180                 }
 3181         } while (node != NULL);
 3182 
 3183         hashdestroy(V_ng_name_hash, M_NETGRAPH_NODE, V_ng_name_hmask);
 3184         hashdestroy(V_ng_ID_hash, M_NETGRAPH_NODE, V_ng_ID_hmask);
 3185 }
 3186 VNET_SYSUNINIT(vnet_netgraph_uninit, SI_SUB_NETGRAPH, SI_ORDER_FIRST,
 3187     vnet_netgraph_uninit, NULL);
 3188 #endif /* VIMAGE */
 3189 
 3190 /*
 3191  * Handle loading and unloading for this code.
 3192  * The only thing we need to link into is the NETISR strucure.
 3193  */
 3194 static int
 3195 ngb_mod_event(module_t mod, int event, void *data)
 3196 {
 3197         struct proc *p;
 3198         struct thread *td;
 3199         int i, error = 0;
 3200 
 3201         switch (event) {
 3202         case MOD_LOAD:
 3203                 /* Initialize everything. */
 3204                 NG_WORKLIST_LOCK_INIT();
 3205                 rw_init(&ng_typelist_lock, "netgraph types");
 3206                 rw_init(&ng_idhash_lock, "netgraph idhash");
 3207                 rw_init(&ng_namehash_lock, "netgraph namehash");
 3208                 rw_init(&ng_topo_lock, "netgraph topology mutex");
 3209 #ifdef  NETGRAPH_DEBUG
 3210                 mtx_init(&ng_nodelist_mtx, "netgraph nodelist mutex", NULL,
 3211                     MTX_DEF);
 3212                 mtx_init(&ngq_mtx, "netgraph item list mutex", NULL,
 3213                     MTX_DEF);
 3214 #endif
 3215                 ng_qzone = uma_zcreate("NetGraph items", sizeof(struct ng_item),
 3216                     NULL, NULL, NULL, NULL, UMA_ALIGN_CACHE, 0);
 3217                 uma_zone_set_max(ng_qzone, maxalloc);
 3218                 ng_qdzone = uma_zcreate("NetGraph data items",
 3219                     sizeof(struct ng_item), NULL, NULL, NULL, NULL,
 3220                     UMA_ALIGN_CACHE, 0);
 3221                 uma_zone_set_max(ng_qdzone, maxdata);
 3222                 /* Autoconfigure number of threads. */
 3223                 if (numthreads <= 0)
 3224                         numthreads = mp_ncpus;
 3225                 /* Create threads. */
 3226                 p = NULL; /* start with no process */
 3227                 for (i = 0; i < numthreads; i++) {
 3228                         if (kproc_kthread_add(ngthread, NULL, &p, &td,
 3229                             RFHIGHPID, 0, "ng_queue", "ng_queue%d", i)) {
 3230                                 numthreads = i;
 3231                                 break;
 3232                         }
 3233                 }
 3234                 break;
 3235         case MOD_UNLOAD:
 3236                 /* You can't unload it because an interface may be using it. */
 3237                 error = EBUSY;
 3238                 break;
 3239         default:
 3240                 error = EOPNOTSUPP;
 3241                 break;
 3242         }
 3243         return (error);
 3244 }
 3245 
 3246 static moduledata_t netgraph_mod = {
 3247         "netgraph",
 3248         ngb_mod_event,
 3249         (NULL)
 3250 };
 3251 DECLARE_MODULE(netgraph, netgraph_mod, SI_SUB_NETGRAPH, SI_ORDER_FIRST);
 3252 SYSCTL_NODE(_net, OID_AUTO, graph, CTLFLAG_RW, 0, "netgraph Family");
 3253 SYSCTL_INT(_net_graph, OID_AUTO, abi_version, CTLFLAG_RD, SYSCTL_NULL_INT_PTR, NG_ABI_VERSION,"");
 3254 SYSCTL_INT(_net_graph, OID_AUTO, msg_version, CTLFLAG_RD, SYSCTL_NULL_INT_PTR, NG_VERSION, "");
 3255 
 3256 #ifdef  NETGRAPH_DEBUG
 3257 void
 3258 dumphook (hook_p hook, char *file, int line)
 3259 {
 3260         printf("hook: name %s, %d refs, Last touched:\n",
 3261                 _NG_HOOK_NAME(hook), hook->hk_refs);
 3262         printf("        Last active @ %s, line %d\n",
 3263                 hook->lastfile, hook->lastline);
 3264         if (line) {
 3265                 printf(" problem discovered at file %s, line %d\n", file, line);
 3266 #ifdef KDB
 3267                 kdb_backtrace();
 3268 #endif
 3269         }
 3270 }
 3271 
 3272 void
 3273 dumpnode(node_p node, char *file, int line)
 3274 {
 3275         printf("node: ID [%x]: type '%s', %d hooks, flags 0x%x, %d refs, %s:\n",
 3276                 _NG_NODE_ID(node), node->nd_type->name,
 3277                 node->nd_numhooks, node->nd_flags,
 3278                 node->nd_refs, node->nd_name);
 3279         printf("        Last active @ %s, line %d\n",
 3280                 node->lastfile, node->lastline);
 3281         if (line) {
 3282                 printf(" problem discovered at file %s, line %d\n", file, line);
 3283 #ifdef KDB
 3284                 kdb_backtrace();
 3285 #endif
 3286         }
 3287 }
 3288 
 3289 void
 3290 dumpitem(item_p item, char *file, int line)
 3291 {
 3292         printf(" ACTIVE item, last used at %s, line %d",
 3293                 item->lastfile, item->lastline);
 3294         switch(item->el_flags & NGQF_TYPE) {
 3295         case NGQF_DATA:
 3296                 printf(" - [data]\n");
 3297                 break;
 3298         case NGQF_MESG:
 3299                 printf(" - retaddr[%d]:\n", _NGI_RETADDR(item));
 3300                 break;
 3301         case NGQF_FN:
 3302                 printf(" - fn@%p (%p, %p, %p, %d (%x))\n",
 3303                         _NGI_FN(item),
 3304                         _NGI_NODE(item),
 3305                         _NGI_HOOK(item),
 3306                         item->body.fn.fn_arg1,
 3307                         item->body.fn.fn_arg2,
 3308                         item->body.fn.fn_arg2);
 3309                 break;
 3310         case NGQF_FN2:
 3311                 printf(" - fn2@%p (%p, %p, %p, %d (%x))\n",
 3312                         _NGI_FN2(item),
 3313                         _NGI_NODE(item),
 3314                         _NGI_HOOK(item),
 3315                         item->body.fn.fn_arg1,
 3316                         item->body.fn.fn_arg2,
 3317                         item->body.fn.fn_arg2);
 3318                 break;
 3319         }
 3320         if (line) {
 3321                 printf(" problem discovered at file %s, line %d\n", file, line);
 3322                 if (_NGI_NODE(item)) {
 3323                         printf("node %p ([%x])\n",
 3324                                 _NGI_NODE(item), ng_node2ID(_NGI_NODE(item)));
 3325                 }
 3326         }
 3327 }
 3328 
 3329 static void
 3330 ng_dumpitems(void)
 3331 {
 3332         item_p item;
 3333         int i = 1;
 3334         TAILQ_FOREACH(item, &ng_itemlist, all) {
 3335                 printf("[%d] ", i++);
 3336                 dumpitem(item, NULL, 0);
 3337         }
 3338 }
 3339 
 3340 static void
 3341 ng_dumpnodes(void)
 3342 {
 3343         node_p node;
 3344         int i = 1;
 3345         mtx_lock(&ng_nodelist_mtx);
 3346         SLIST_FOREACH(node, &ng_allnodes, nd_all) {
 3347                 printf("[%d] ", i++);
 3348                 dumpnode(node, NULL, 0);
 3349         }
 3350         mtx_unlock(&ng_nodelist_mtx);
 3351 }
 3352 
 3353 static void
 3354 ng_dumphooks(void)
 3355 {
 3356         hook_p hook;
 3357         int i = 1;
 3358         mtx_lock(&ng_nodelist_mtx);
 3359         SLIST_FOREACH(hook, &ng_allhooks, hk_all) {
 3360                 printf("[%d] ", i++);
 3361                 dumphook(hook, NULL, 0);
 3362         }
 3363         mtx_unlock(&ng_nodelist_mtx);
 3364 }
 3365 
 3366 static int
 3367 sysctl_debug_ng_dump_items(SYSCTL_HANDLER_ARGS)
 3368 {
 3369         int error;
 3370         int val;
 3371         int i;
 3372 
 3373         val = allocated;
 3374         i = 1;
 3375         error = sysctl_handle_int(oidp, &val, 0, req);
 3376         if (error != 0 || req->newptr == NULL)
 3377                 return (error);
 3378         if (val == 42) {
 3379                 ng_dumpitems();
 3380                 ng_dumpnodes();
 3381                 ng_dumphooks();
 3382         }
 3383         return (0);
 3384 }
 3385 
 3386 SYSCTL_PROC(_debug, OID_AUTO, ng_dump_items, CTLTYPE_INT | CTLFLAG_RW,
 3387     0, sizeof(int), sysctl_debug_ng_dump_items, "I", "Number of allocated items");
 3388 #endif  /* NETGRAPH_DEBUG */
 3389 
 3390 /***********************************************************************
 3391 * Worklist routines
 3392 **********************************************************************/
 3393 /*
 3394  * Pick a node off the list of nodes with work,
 3395  * try get an item to process off it. Remove the node from the list.
 3396  */
 3397 static void
 3398 ngthread(void *arg)
 3399 {
 3400         for (;;) {
 3401                 node_p  node;
 3402 
 3403                 /* Get node from the worklist. */
 3404                 NG_WORKLIST_LOCK();
 3405                 while ((node = STAILQ_FIRST(&ng_worklist)) == NULL)
 3406                         NG_WORKLIST_SLEEP();
 3407                 STAILQ_REMOVE_HEAD(&ng_worklist, nd_input_queue.q_work);
 3408                 NG_WORKLIST_UNLOCK();
 3409                 CURVNET_SET(node->nd_vnet);
 3410                 CTR3(KTR_NET, "%20s: node [%x] (%p) taken off worklist",
 3411                     __func__, node->nd_ID, node);
 3412                 /*
 3413                  * We have the node. We also take over the reference
 3414                  * that the list had on it.
 3415                  * Now process as much as you can, until it won't
 3416                  * let you have another item off the queue.
 3417                  * All this time, keep the reference
 3418                  * that lets us be sure that the node still exists.
 3419                  * Let the reference go at the last minute.
 3420                  */
 3421                 for (;;) {
 3422                         item_p item;
 3423                         int rw;
 3424 
 3425                         NG_QUEUE_LOCK(&node->nd_input_queue);
 3426                         item = ng_dequeue(node, &rw);
 3427                         if (item == NULL) {
 3428                                 node->nd_input_queue.q_flags2 &= ~NGQ2_WORKQ;
 3429                                 NG_QUEUE_UNLOCK(&node->nd_input_queue);
 3430                                 break; /* go look for another node */
 3431                         } else {
 3432                                 NG_QUEUE_UNLOCK(&node->nd_input_queue);
 3433                                 NGI_GET_NODE(item, node); /* zaps stored node */
 3434                                 ng_apply_item(node, item, rw);
 3435                                 NG_NODE_UNREF(node);
 3436                         }
 3437                 }
 3438                 NG_NODE_UNREF(node);
 3439                 CURVNET_RESTORE();
 3440         }
 3441 }
 3442 
 3443 /*
 3444  * XXX
 3445  * It's posible that a debugging NG_NODE_REF may need
 3446  * to be outside the mutex zone
 3447  */
 3448 static void
 3449 ng_worklist_add(node_p node)
 3450 {
 3451 
 3452         mtx_assert(&node->nd_input_queue.q_mtx, MA_OWNED);
 3453 
 3454         if ((node->nd_input_queue.q_flags2 & NGQ2_WORKQ) == 0) {
 3455                 /*
 3456                  * If we are not already on the work queue,
 3457                  * then put us on.
 3458                  */
 3459                 node->nd_input_queue.q_flags2 |= NGQ2_WORKQ;
 3460                 NG_NODE_REF(node); /* XXX safe in mutex? */
 3461                 NG_WORKLIST_LOCK();
 3462                 STAILQ_INSERT_TAIL(&ng_worklist, node, nd_input_queue.q_work);
 3463                 NG_WORKLIST_UNLOCK();
 3464                 CTR3(KTR_NET, "%20s: node [%x] (%p) put on worklist", __func__,
 3465                     node->nd_ID, node);
 3466                 NG_WORKLIST_WAKEUP();
 3467         } else {
 3468                 CTR3(KTR_NET, "%20s: node [%x] (%p) already on worklist",
 3469                     __func__, node->nd_ID, node);
 3470         }
 3471 }
 3472 
 3473 /***********************************************************************
 3474 * Externally useable functions to set up a queue item ready for sending
 3475 ***********************************************************************/
 3476 
 3477 #ifdef  NETGRAPH_DEBUG
 3478 #define ITEM_DEBUG_CHECKS                                               \
 3479         do {                                                            \
 3480                 if (NGI_NODE(item) ) {                                  \
 3481                         printf("item already has node");                \
 3482                         kdb_enter(KDB_WHY_NETGRAPH, "has node");        \
 3483                         NGI_CLR_NODE(item);                             \
 3484                 }                                                       \
 3485                 if (NGI_HOOK(item) ) {                                  \
 3486                         printf("item already has hook");                \
 3487                         kdb_enter(KDB_WHY_NETGRAPH, "has hook");        \
 3488                         NGI_CLR_HOOK(item);                             \
 3489                 }                                                       \
 3490         } while (0)
 3491 #else
 3492 #define ITEM_DEBUG_CHECKS
 3493 #endif
 3494 
 3495 /*
 3496  * Put mbuf into the item.
 3497  * Hook and node references will be removed when the item is dequeued.
 3498  * (or equivalent)
 3499  * (XXX) Unsafe because no reference held by peer on remote node.
 3500  * remote node might go away in this timescale.
 3501  * We know the hooks can't go away because that would require getting
 3502  * a writer item on both nodes and we must have at least a  reader
 3503  * here to be able to do this.
 3504  * Note that the hook loaded is the REMOTE hook.
 3505  *
 3506  * This is possibly in the critical path for new data.
 3507  */
 3508 item_p
 3509 ng_package_data(struct mbuf *m, int flags)
 3510 {
 3511         item_p item;
 3512 
 3513         if ((item = ng_alloc_item(NGQF_DATA, flags)) == NULL) {
 3514                 NG_FREE_M(m);
 3515                 return (NULL);
 3516         }
 3517         ITEM_DEBUG_CHECKS;
 3518         item->el_flags |= NGQF_READER;
 3519         NGI_M(item) = m;
 3520         return (item);
 3521 }
 3522 
 3523 /*
 3524  * Allocate a queue item and put items into it..
 3525  * Evaluate the address as this will be needed to queue it and
 3526  * to work out what some of the fields should be.
 3527  * Hook and node references will be removed when the item is dequeued.
 3528  * (or equivalent)
 3529  */
 3530 item_p
 3531 ng_package_msg(struct ng_mesg *msg, int flags)
 3532 {
 3533         item_p item;
 3534 
 3535         if ((item = ng_alloc_item(NGQF_MESG, flags)) == NULL) {
 3536                 NG_FREE_MSG(msg);
 3537                 return (NULL);
 3538         }
 3539         ITEM_DEBUG_CHECKS;
 3540         /* Messages items count as writers unless explicitly exempted. */
 3541         if (msg->header.cmd & NGM_READONLY)
 3542                 item->el_flags |= NGQF_READER;
 3543         else
 3544                 item->el_flags |= NGQF_WRITER;
 3545         /*
 3546          * Set the current lasthook into the queue item
 3547          */
 3548         NGI_MSG(item) = msg;
 3549         NGI_RETADDR(item) = 0;
 3550         return (item);
 3551 }
 3552 
 3553 #define SET_RETADDR(item, here, retaddr)                                \
 3554         do {    /* Data or fn items don't have retaddrs */              \
 3555                 if ((item->el_flags & NGQF_TYPE) == NGQF_MESG) {        \
 3556                         if (retaddr) {                                  \
 3557                                 NGI_RETADDR(item) = retaddr;            \
 3558                         } else {                                        \
 3559                                 /*                                      \
 3560                                  * The old return address should be ok. \
 3561                                  * If there isn't one, use the address  \
 3562                                  * here.                                \
 3563                                  */                                     \
 3564                                 if (NGI_RETADDR(item) == 0) {           \
 3565                                         NGI_RETADDR(item)               \
 3566                                                 = ng_node2ID(here);     \
 3567                                 }                                       \
 3568                         }                                               \
 3569                 }                                                       \
 3570         } while (0)
 3571 
 3572 int
 3573 ng_address_hook(node_p here, item_p item, hook_p hook, ng_ID_t retaddr)
 3574 {
 3575         hook_p peer;
 3576         node_p peernode;
 3577         ITEM_DEBUG_CHECKS;
 3578         /*
 3579          * Quick sanity check..
 3580          * Since a hook holds a reference on it's node, once we know
 3581          * that the peer is still connected (even if invalid,) we know
 3582          * that the peer node is present, though maybe invalid.
 3583          */
 3584         TOPOLOGY_RLOCK();
 3585         if ((hook == NULL) || NG_HOOK_NOT_VALID(hook) ||
 3586             NG_HOOK_NOT_VALID(peer = NG_HOOK_PEER(hook)) ||
 3587             NG_NODE_NOT_VALID(peernode = NG_PEER_NODE(hook))) {
 3588                 NG_FREE_ITEM(item);
 3589                 TRAP_ERROR();
 3590                 TOPOLOGY_RUNLOCK();
 3591                 return (ENETDOWN);
 3592         }
 3593 
 3594         /*
 3595          * Transfer our interest to the other (peer) end.
 3596          */
 3597         NG_HOOK_REF(peer);
 3598         NG_NODE_REF(peernode);
 3599         NGI_SET_HOOK(item, peer);
 3600         NGI_SET_NODE(item, peernode);
 3601         SET_RETADDR(item, here, retaddr);
 3602 
 3603         TOPOLOGY_RUNLOCK();
 3604 
 3605         return (0);
 3606 }
 3607 
 3608 int
 3609 ng_address_path(node_p here, item_p item, const char *address, ng_ID_t retaddr)
 3610 {
 3611         node_p  dest = NULL;
 3612         hook_p  hook = NULL;
 3613         int     error;
 3614 
 3615         ITEM_DEBUG_CHECKS;
 3616         /*
 3617          * Note that ng_path2noderef increments the reference count
 3618          * on the node for us if it finds one. So we don't have to.
 3619          */
 3620         error = ng_path2noderef(here, address, &dest, &hook);
 3621         if (error) {
 3622                 NG_FREE_ITEM(item);
 3623                 return (error);
 3624         }
 3625         NGI_SET_NODE(item, dest);
 3626         if (hook)
 3627                 NGI_SET_HOOK(item, hook);
 3628 
 3629         SET_RETADDR(item, here, retaddr);
 3630         return (0);
 3631 }
 3632 
 3633 int
 3634 ng_address_ID(node_p here, item_p item, ng_ID_t ID, ng_ID_t retaddr)
 3635 {
 3636         node_p dest;
 3637 
 3638         ITEM_DEBUG_CHECKS;
 3639         /*
 3640          * Find the target node.
 3641          */
 3642         dest = ng_ID2noderef(ID); /* GETS REFERENCE! */
 3643         if (dest == NULL) {
 3644                 NG_FREE_ITEM(item);
 3645                 TRAP_ERROR();
 3646                 return(EINVAL);
 3647         }
 3648         /* Fill out the contents */
 3649         NGI_SET_NODE(item, dest);
 3650         NGI_CLR_HOOK(item);
 3651         SET_RETADDR(item, here, retaddr);
 3652         return (0);
 3653 }
 3654 
 3655 /*
 3656  * special case to send a message to self (e.g. destroy node)
 3657  * Possibly indicate an arrival hook too.
 3658  * Useful for removing that hook :-)
 3659  */
 3660 item_p
 3661 ng_package_msg_self(node_p here, hook_p hook, struct ng_mesg *msg)
 3662 {
 3663         item_p item;
 3664 
 3665         /*
 3666          * Find the target node.
 3667          * If there is a HOOK argument, then use that in preference
 3668          * to the address.
 3669          */
 3670         if ((item = ng_alloc_item(NGQF_MESG, NG_NOFLAGS)) == NULL) {
 3671                 NG_FREE_MSG(msg);
 3672                 return (NULL);
 3673         }
 3674 
 3675         /* Fill out the contents */
 3676         item->el_flags |= NGQF_WRITER;
 3677         NG_NODE_REF(here);
 3678         NGI_SET_NODE(item, here);
 3679         if (hook) {
 3680                 NG_HOOK_REF(hook);
 3681                 NGI_SET_HOOK(item, hook);
 3682         }
 3683         NGI_MSG(item) = msg;
 3684         NGI_RETADDR(item) = ng_node2ID(here);
 3685         return (item);
 3686 }
 3687 
 3688 /*
 3689  * Send ng_item_fn function call to the specified node.
 3690  */
 3691 
 3692 int
 3693 ng_send_fn(node_p node, hook_p hook, ng_item_fn *fn, void * arg1, int arg2)
 3694 {
 3695 
 3696         return ng_send_fn1(node, hook, fn, arg1, arg2, NG_NOFLAGS);
 3697 }
 3698 
 3699 int
 3700 ng_send_fn1(node_p node, hook_p hook, ng_item_fn *fn, void * arg1, int arg2,
 3701         int flags)
 3702 {
 3703         item_p item;
 3704 
 3705         if ((item = ng_alloc_item(NGQF_FN, flags)) == NULL) {
 3706                 return (ENOMEM);
 3707         }
 3708         item->el_flags |= NGQF_WRITER;
 3709         NG_NODE_REF(node); /* and one for the item */
 3710         NGI_SET_NODE(item, node);
 3711         if (hook) {
 3712                 NG_HOOK_REF(hook);
 3713                 NGI_SET_HOOK(item, hook);
 3714         }
 3715         NGI_FN(item) = fn;
 3716         NGI_ARG1(item) = arg1;
 3717         NGI_ARG2(item) = arg2;
 3718         return(ng_snd_item(item, flags));
 3719 }
 3720 
 3721 /*
 3722  * Send ng_item_fn2 function call to the specified node.
 3723  *
 3724  * If an optional pitem parameter is supplied, its apply
 3725  * callback will be copied to the new item. If also NG_REUSE_ITEM
 3726  * flag is set, no new item will be allocated, but pitem will
 3727  * be used.
 3728  */
 3729 int
 3730 ng_send_fn2(node_p node, hook_p hook, item_p pitem, ng_item_fn2 *fn, void *arg1,
 3731         int arg2, int flags)
 3732 {
 3733         item_p item;
 3734 
 3735         KASSERT((pitem != NULL || (flags & NG_REUSE_ITEM) == 0),
 3736             ("%s: NG_REUSE_ITEM but no pitem", __func__));
 3737 
 3738         /*
 3739          * Allocate a new item if no supplied or
 3740          * if we can't use supplied one.
 3741          */
 3742         if (pitem == NULL || (flags & NG_REUSE_ITEM) == 0) {
 3743                 if ((item = ng_alloc_item(NGQF_FN2, flags)) == NULL)
 3744                         return (ENOMEM);
 3745                 if (pitem != NULL)
 3746                         item->apply = pitem->apply;
 3747         } else {
 3748                 if ((item = ng_realloc_item(pitem, NGQF_FN2, flags)) == NULL)
 3749                         return (ENOMEM);
 3750         }
 3751 
 3752         item->el_flags = (item->el_flags & ~NGQF_RW) | NGQF_WRITER;
 3753         NG_NODE_REF(node); /* and one for the item */
 3754         NGI_SET_NODE(item, node);
 3755         if (hook) {
 3756                 NG_HOOK_REF(hook);
 3757                 NGI_SET_HOOK(item, hook);
 3758         }
 3759         NGI_FN2(item) = fn;
 3760         NGI_ARG1(item) = arg1;
 3761         NGI_ARG2(item) = arg2;
 3762         return(ng_snd_item(item, flags));
 3763 }
 3764 
 3765 /*
 3766  * Official timeout routines for Netgraph nodes.
 3767  */
 3768 static void
 3769 ng_callout_trampoline(void *arg)
 3770 {
 3771         item_p item = arg;
 3772 
 3773         CURVNET_SET(NGI_NODE(item)->nd_vnet);
 3774         ng_snd_item(item, 0);
 3775         CURVNET_RESTORE();
 3776 }
 3777 
 3778 int
 3779 ng_callout(struct callout *c, node_p node, hook_p hook, int ticks,
 3780     ng_item_fn *fn, void * arg1, int arg2)
 3781 {
 3782         item_p item, oitem;
 3783 
 3784         if ((item = ng_alloc_item(NGQF_FN, NG_NOFLAGS)) == NULL)
 3785                 return (ENOMEM);
 3786 
 3787         item->el_flags |= NGQF_WRITER;
 3788         NG_NODE_REF(node);              /* and one for the item */
 3789         NGI_SET_NODE(item, node);
 3790         if (hook) {
 3791                 NG_HOOK_REF(hook);
 3792                 NGI_SET_HOOK(item, hook);
 3793         }
 3794         NGI_FN(item) = fn;
 3795         NGI_ARG1(item) = arg1;
 3796         NGI_ARG2(item) = arg2;
 3797         oitem = c->c_arg;
 3798         if (callout_reset(c, ticks, &ng_callout_trampoline, item) == 1 &&
 3799             oitem != NULL)
 3800                 NG_FREE_ITEM(oitem);
 3801         return (0);
 3802 }
 3803 
 3804 /* A special modified version of untimeout() */
 3805 int
 3806 ng_uncallout(struct callout *c, node_p node)
 3807 {
 3808         item_p item;
 3809         int rval;
 3810 
 3811         KASSERT(c != NULL, ("ng_uncallout: NULL callout"));
 3812         KASSERT(node != NULL, ("ng_uncallout: NULL node"));
 3813 
 3814         rval = callout_stop(c);
 3815         item = c->c_arg;
 3816         /* Do an extra check */
 3817         if ((rval > 0) && (c->c_func == &ng_callout_trampoline) &&
 3818             (NGI_NODE(item) == node)) {
 3819                 /*
 3820                  * We successfully removed it from the queue before it ran
 3821                  * So now we need to unreference everything that was
 3822                  * given extra references. (NG_FREE_ITEM does this).
 3823                  */
 3824                 NG_FREE_ITEM(item);
 3825         }
 3826         c->c_arg = NULL;
 3827 
 3828         /*
 3829          * Callers only want to know if the callout was cancelled and
 3830          * not draining or stopped.
 3831          */
 3832         return (rval > 0);
 3833 }
 3834 
 3835 /*
 3836  * Set the address, if none given, give the node here.
 3837  */
 3838 void
 3839 ng_replace_retaddr(node_p here, item_p item, ng_ID_t retaddr)
 3840 {
 3841         if (retaddr) {
 3842                 NGI_RETADDR(item) = retaddr;
 3843         } else {
 3844                 /*
 3845                  * The old return address should be ok.
 3846                  * If there isn't one, use the address here.
 3847                  */
 3848                 NGI_RETADDR(item) = ng_node2ID(here);
 3849         }
 3850 }

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