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


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

FreeBSD/Linux Kernel Cross Reference
sys/netgraph/ng_l2tp.c

Version: -  FREEBSD  -  FREEBSD-12-STABLE  -  FREEBSD-12-0  -  FREEBSD-11-STABLE  -  FREEBSD-11-2  -  FREEBSD-11-1  -  FREEBSD-11-0  -  FREEBSD-10-STABLE  -  FREEBSD-10-4  -  FREEBSD-10-3  -  FREEBSD-10-2  -  FREEBSD-10-1  -  FREEBSD-10-0  -  FREEBSD-9-STABLE  -  FREEBSD-9-3  -  FREEBSD-9-2  -  FREEBSD-9-1  -  FREEBSD-9-0  -  FREEBSD-8-STABLE  -  FREEBSD-8-4  -  FREEBSD-8-3  -  FREEBSD-8-2  -  FREEBSD-8-1  -  FREEBSD-8-0  -  FREEBSD-7-STABLE  -  FREEBSD-7-4  -  FREEBSD-7-3  -  FREEBSD-7-2  -  FREEBSD-7-1  -  FREEBSD-7-0  -  FREEBSD-6-STABLE  -  FREEBSD-6-4  -  FREEBSD-6-3  -  FREEBSD-6-2  -  FREEBSD-6-1  -  FREEBSD-6-0  -  FREEBSD-5-STABLE  -  FREEBSD-5-5  -  FREEBSD-5-4  -  FREEBSD-5-3  -  FREEBSD-5-2  -  FREEBSD-5-1  -  FREEBSD-5-0  -  FREEBSD-4-STABLE  -  FREEBSD-3-STABLE  -  FREEBSD22  -  linux-2.6  -  linux-2.4.22  -  MK83  -  MK84  -  PLAN9  -  DFBSD  -  NETBSD  -  NETBSD5  -  NETBSD4  -  NETBSD3  -  NETBSD20  -  OPENBSD  -  xnu-517  -  xnu-792  -  xnu-792.6.70  -  xnu-1228  -  xnu-1456.1.26  -  xnu-1699.24.8  -  xnu-2050.18.24  -  OPENSOLARIS  -  minix-3-1-1 
SearchContext: -  none  -  3  -  10 

    1 /*-
    2  * Copyright (c) 2001-2002 Packet Design, LLC.
    3  * All rights reserved.
    4  * 
    5  * Subject to the following obligations and disclaimer of warranty,
    6  * use and redistribution of this software, in source or object code
    7  * forms, with or without modifications are expressly permitted by
    8  * Packet Design; provided, however, that:
    9  * 
   10  *    (i)  Any and all reproductions of the source or object code
   11  *         must include the copyright notice above and the following
   12  *         disclaimer of warranties; and
   13  *    (ii) No rights are granted, in any manner or form, to use
   14  *         Packet Design trademarks, including the mark "PACKET DESIGN"
   15  *         on advertising, endorsements, or otherwise except as such
   16  *         appears in the above copyright notice or in the software.
   17  * 
   18  * THIS SOFTWARE IS BEING PROVIDED BY PACKET DESIGN "AS IS", AND
   19  * TO THE MAXIMUM EXTENT PERMITTED BY LAW, PACKET DESIGN MAKES NO
   20  * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING
   21  * THIS SOFTWARE, INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED
   22  * WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE,
   23  * OR NON-INFRINGEMENT.  PACKET DESIGN DOES NOT WARRANT, GUARANTEE,
   24  * OR MAKE ANY REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS
   25  * OF THE USE OF THIS SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY,
   26  * RELIABILITY OR OTHERWISE.  IN NO EVENT SHALL PACKET DESIGN BE
   27  * LIABLE FOR ANY DAMAGES RESULTING FROM OR ARISING OUT OF ANY USE
   28  * OF THIS SOFTWARE, INCLUDING WITHOUT LIMITATION, ANY DIRECT,
   29  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, PUNITIVE, OR CONSEQUENTIAL
   30  * DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, LOSS OF
   31  * USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY THEORY OF
   32  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   33  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
   34  * THE USE OF THIS SOFTWARE, EVEN IF PACKET DESIGN IS ADVISED OF
   35  * THE POSSIBILITY OF SUCH DAMAGE.
   36  * 
   37  * Author: Archie Cobbs <archie@freebsd.org>
   38  *
   39  * $FreeBSD: releng/11.1/sys/netgraph/ng_l2tp.c 260225 2014-01-03 12:06:54Z glebius $
   40  */
   41 
   42 /*
   43  * L2TP netgraph node type.
   44  *
   45  * This node type implements the lower layer of the
   46  * L2TP protocol as specified in RFC 2661.
   47  */
   48 
   49 #include <sys/param.h>
   50 #include <sys/systm.h>
   51 #include <sys/kernel.h>
   52 #include <sys/time.h>
   53 #include <sys/conf.h>
   54 #include <sys/mbuf.h>
   55 #include <sys/malloc.h>
   56 #include <sys/errno.h>
   57 #include <sys/libkern.h>
   58 
   59 #include <netgraph/ng_message.h>
   60 #include <netgraph/netgraph.h>
   61 #include <netgraph/ng_parse.h>
   62 #include <netgraph/ng_l2tp.h>
   63 
   64 #ifdef NG_SEPARATE_MALLOC
   65 static MALLOC_DEFINE(M_NETGRAPH_L2TP, "netgraph_l2tp", "netgraph l2tp node");
   66 #else
   67 #define M_NETGRAPH_L2TP M_NETGRAPH
   68 #endif
   69 
   70 /* L2TP header format (first 2 bytes only) */
   71 #define L2TP_HDR_CTRL           0x8000                  /* control packet */
   72 #define L2TP_HDR_LEN            0x4000                  /* has length field */
   73 #define L2TP_HDR_SEQ            0x0800                  /* has ns, nr fields */
   74 #define L2TP_HDR_OFF            0x0200                  /* has offset field */
   75 #define L2TP_HDR_PRIO           0x0100                  /* give priority */
   76 #define L2TP_HDR_VERS_MASK      0x000f                  /* version field mask */
   77 #define L2TP_HDR_VERSION        0x0002                  /* version field */
   78 
   79 /* Bits that must be zero or one in first two bytes of header */
   80 #define L2TP_CTRL_0BITS         0x030d                  /* ctrl: must be 0 */
   81 #define L2TP_CTRL_1BITS         0xc802                  /* ctrl: must be 1 */
   82 #define L2TP_DATA_0BITS         0x800d                  /* data: must be 0 */
   83 #define L2TP_DATA_1BITS         0x0002                  /* data: must be 1 */
   84 
   85 /* Standard xmit ctrl and data header bits */
   86 #define L2TP_CTRL_HDR           (L2TP_HDR_CTRL | L2TP_HDR_LEN \
   87                                     | L2TP_HDR_SEQ | L2TP_HDR_VERSION)
   88 #define L2TP_DATA_HDR           (L2TP_HDR_VERSION)      /* optional: len, seq */
   89 
   90 /* Some hard coded values */
   91 #define L2TP_MAX_XWIN           128                     /* my max xmit window */
   92 #define L2TP_MAX_REXMIT         5                       /* default max rexmit */
   93 #define L2TP_MAX_REXMIT_TO      30                      /* default rexmit to */
   94 #define L2TP_DELAYED_ACK        ((hz + 19) / 20)        /* delayed ack: 50 ms */
   95 
   96 /* Default data sequence number configuration for new sessions */
   97 #define L2TP_CONTROL_DSEQ       1                       /* we are the lns */
   98 #define L2TP_ENABLE_DSEQ        1                       /* enable data seq # */
   99 
  100 /* Compare sequence numbers using circular math */
  101 #define L2TP_SEQ_DIFF(x, y)     ((int16_t)((x) - (y)))
  102 
  103 #define SESSHASHSIZE            0x0020
  104 #define SESSHASH(x)             (((x) ^ ((x) >> 8)) & (SESSHASHSIZE - 1))
  105 
  106 /* Hook private data (data session hooks only) */
  107 struct ng_l2tp_hook_private {
  108         struct ng_l2tp_sess_config      conf;   /* hook/session config */
  109         struct ng_l2tp_session_stats    stats;  /* per sessions statistics */
  110         hook_p                          hook;   /* hook reference */
  111         u_int16_t                       ns;     /* data ns sequence number */
  112         u_int16_t                       nr;     /* data nr sequence number */
  113         LIST_ENTRY(ng_l2tp_hook_private) sessions;
  114 };
  115 typedef struct ng_l2tp_hook_private *hookpriv_p;
  116 
  117 /*
  118  * Sequence number state
  119  *
  120  * Invariants:
  121  *    - If cwnd < ssth, we're doing slow start, otherwise congestion avoidance
  122  *    - The number of unacknowledged xmit packets is (ns - rack) <= seq->wmax
  123  *    - The first (ns - rack) mbuf's in xwin[] array are copies of these
  124  *      unacknowledged packets; the remainder of xwin[] consists first of
  125  *      zero or more further untransmitted packets in the transmit queue
  126  *    - We try to keep the peer's receive window as full as possible.
  127  *      Therefore, (i < cwnd && xwin[i] != NULL) implies (ns - rack) > i.
  128  *    - rack_timer is running iff (ns - rack) > 0 (unack'd xmit'd pkts)
  129  *    - If xack != nr, there are unacknowledged recv packet(s) (delayed ack)
  130  *    - xack_timer is running iff xack != nr (unack'd rec'd pkts)
  131  */
  132 struct l2tp_seq {
  133         u_int16_t               ns;             /* next xmit seq we send */
  134         u_int16_t               nr;             /* next recv seq we expect */
  135         u_int16_t               inproc;         /* packet is in processing */
  136         u_int16_t               rack;           /* last 'nr' we rec'd */
  137         u_int16_t               xack;           /* last 'nr' we sent */
  138         u_int16_t               wmax;           /* peer's max recv window */
  139         u_int16_t               cwnd;           /* current congestion window */
  140         u_int16_t               ssth;           /* slow start threshold */
  141         u_int16_t               acks;           /* # consecutive acks rec'd */
  142         u_int16_t               rexmits;        /* # retransmits sent */
  143         struct callout          rack_timer;     /* retransmit timer */
  144         struct callout          xack_timer;     /* delayed ack timer */
  145         struct mbuf             *xwin[L2TP_MAX_XWIN];   /* transmit window */
  146         struct mtx              mtx;                    /* seq mutex */
  147 };
  148 
  149 /* Node private data */
  150 struct ng_l2tp_private {
  151         node_p                  node;           /* back pointer to node */
  152         hook_p                  ctrl;           /* hook to upper layers */
  153         hook_p                  lower;          /* hook to lower layers */
  154         struct ng_l2tp_config   conf;           /* node configuration */
  155         struct ng_l2tp_stats    stats;          /* node statistics */
  156         struct l2tp_seq         seq;            /* ctrl sequence number state */
  157         ng_ID_t                 ftarget;        /* failure message target */
  158         LIST_HEAD(, ng_l2tp_hook_private) sesshash[SESSHASHSIZE];
  159 };
  160 typedef struct ng_l2tp_private *priv_p;
  161 
  162 /* Netgraph node methods */
  163 static ng_constructor_t ng_l2tp_constructor;
  164 static ng_rcvmsg_t      ng_l2tp_rcvmsg;
  165 static ng_shutdown_t    ng_l2tp_shutdown;
  166 static ng_newhook_t     ng_l2tp_newhook;
  167 static ng_rcvdata_t     ng_l2tp_rcvdata;
  168 static ng_rcvdata_t     ng_l2tp_rcvdata_lower;
  169 static ng_rcvdata_t     ng_l2tp_rcvdata_ctrl;
  170 static ng_disconnect_t  ng_l2tp_disconnect;
  171 
  172 /* Internal functions */
  173 static int      ng_l2tp_xmit_ctrl(priv_p priv, struct mbuf *m, u_int16_t ns);
  174 
  175 static void     ng_l2tp_seq_init(priv_p priv);
  176 static int      ng_l2tp_seq_set(priv_p priv,
  177                         const struct ng_l2tp_seq_config *conf);
  178 static int      ng_l2tp_seq_adjust(priv_p priv,
  179                         const struct ng_l2tp_config *conf);
  180 static void     ng_l2tp_seq_reset(priv_p priv);
  181 static void     ng_l2tp_seq_failure(priv_p priv);
  182 static void     ng_l2tp_seq_recv_nr(priv_p priv, u_int16_t nr);
  183 static void     ng_l2tp_seq_xack_timeout(node_p node, hook_p hook,
  184                     void *arg1, int arg2);
  185 static void     ng_l2tp_seq_rack_timeout(node_p node, hook_p hook,
  186                     void *arg1, int arg2);
  187 
  188 static hookpriv_p       ng_l2tp_find_session(priv_p privp, u_int16_t sid);
  189 static ng_fn_eachhook   ng_l2tp_reset_session;
  190 
  191 #ifdef INVARIANTS
  192 static void     ng_l2tp_seq_check(struct l2tp_seq *seq);
  193 #endif
  194 
  195 /* Parse type for struct ng_l2tp_seq_config. */
  196 static const struct ng_parse_struct_field
  197         ng_l2tp_seq_config_fields[] = NG_L2TP_SEQ_CONFIG_TYPE_INFO;
  198 static const struct ng_parse_type ng_l2tp_seq_config_type = {
  199         &ng_parse_struct_type,
  200         &ng_l2tp_seq_config_fields
  201 };
  202 
  203 /* Parse type for struct ng_l2tp_config */
  204 static const struct ng_parse_struct_field
  205         ng_l2tp_config_type_fields[] = NG_L2TP_CONFIG_TYPE_INFO;
  206 static const struct ng_parse_type ng_l2tp_config_type = {
  207         &ng_parse_struct_type,
  208         &ng_l2tp_config_type_fields,
  209 };
  210 
  211 /* Parse type for struct ng_l2tp_sess_config */
  212 static const struct ng_parse_struct_field
  213         ng_l2tp_sess_config_type_fields[] = NG_L2TP_SESS_CONFIG_TYPE_INFO;
  214 static const struct ng_parse_type ng_l2tp_sess_config_type = {
  215         &ng_parse_struct_type,
  216         &ng_l2tp_sess_config_type_fields,
  217 };
  218 
  219 /* Parse type for struct ng_l2tp_stats */
  220 static const struct ng_parse_struct_field
  221         ng_l2tp_stats_type_fields[] = NG_L2TP_STATS_TYPE_INFO;
  222 static const struct ng_parse_type ng_l2tp_stats_type = {
  223         &ng_parse_struct_type,
  224         &ng_l2tp_stats_type_fields
  225 };
  226 
  227 /* Parse type for struct ng_l2tp_session_stats. */
  228 static const struct ng_parse_struct_field
  229         ng_l2tp_session_stats_type_fields[] = NG_L2TP_SESSION_STATS_TYPE_INFO;
  230 static const struct ng_parse_type ng_l2tp_session_stats_type = {
  231         &ng_parse_struct_type,
  232         &ng_l2tp_session_stats_type_fields
  233 };
  234 
  235 /* List of commands and how to convert arguments to/from ASCII */
  236 static const struct ng_cmdlist ng_l2tp_cmdlist[] = {
  237         {
  238           NGM_L2TP_COOKIE,
  239           NGM_L2TP_SET_CONFIG,
  240           "setconfig",
  241           &ng_l2tp_config_type,
  242           NULL
  243         },
  244         {
  245           NGM_L2TP_COOKIE,
  246           NGM_L2TP_GET_CONFIG,
  247           "getconfig",
  248           NULL,
  249           &ng_l2tp_config_type
  250         },
  251         {
  252           NGM_L2TP_COOKIE,
  253           NGM_L2TP_SET_SESS_CONFIG,
  254           "setsessconfig",
  255           &ng_l2tp_sess_config_type,
  256           NULL
  257         },
  258         {
  259           NGM_L2TP_COOKIE,
  260           NGM_L2TP_GET_SESS_CONFIG,
  261           "getsessconfig",
  262           &ng_parse_hint16_type,
  263           &ng_l2tp_sess_config_type
  264         },
  265         {
  266           NGM_L2TP_COOKIE,
  267           NGM_L2TP_GET_STATS,
  268           "getstats",
  269           NULL,
  270           &ng_l2tp_stats_type
  271         },
  272         {
  273           NGM_L2TP_COOKIE,
  274           NGM_L2TP_CLR_STATS,
  275           "clrstats",
  276           NULL,
  277           NULL
  278         },
  279         {
  280           NGM_L2TP_COOKIE,
  281           NGM_L2TP_GETCLR_STATS,
  282           "getclrstats",
  283           NULL,
  284           &ng_l2tp_stats_type
  285         },
  286         {
  287           NGM_L2TP_COOKIE,
  288           NGM_L2TP_GET_SESSION_STATS,
  289           "getsessstats",
  290           &ng_parse_int16_type,
  291           &ng_l2tp_session_stats_type
  292         },
  293         {
  294           NGM_L2TP_COOKIE,
  295           NGM_L2TP_CLR_SESSION_STATS,
  296           "clrsessstats",
  297           &ng_parse_int16_type,
  298           NULL
  299         },
  300         {
  301           NGM_L2TP_COOKIE,
  302           NGM_L2TP_GETCLR_SESSION_STATS,
  303           "getclrsessstats",
  304           &ng_parse_int16_type,
  305           &ng_l2tp_session_stats_type
  306         },
  307         {
  308           NGM_L2TP_COOKIE,
  309           NGM_L2TP_ACK_FAILURE,
  310           "ackfailure",
  311           NULL,
  312           NULL
  313         },
  314         {
  315           NGM_L2TP_COOKIE,
  316           NGM_L2TP_SET_SEQ,
  317           "setsequence",
  318           &ng_l2tp_seq_config_type,
  319           NULL
  320         },
  321         { 0 }
  322 };
  323 
  324 /* Node type descriptor */
  325 static struct ng_type ng_l2tp_typestruct = {
  326         .version =      NG_ABI_VERSION,
  327         .name =         NG_L2TP_NODE_TYPE,
  328         .constructor =  ng_l2tp_constructor,
  329         .rcvmsg =       ng_l2tp_rcvmsg,
  330         .shutdown =     ng_l2tp_shutdown,
  331         .newhook =      ng_l2tp_newhook,
  332         .rcvdata =      ng_l2tp_rcvdata,
  333         .disconnect =   ng_l2tp_disconnect,
  334         .cmdlist =      ng_l2tp_cmdlist,
  335 };
  336 NETGRAPH_INIT(l2tp, &ng_l2tp_typestruct);
  337 
  338 /* Sequence number state sanity checking */
  339 #ifdef INVARIANTS
  340 #define L2TP_SEQ_CHECK(seq)     ng_l2tp_seq_check(seq)
  341 #else
  342 #define L2TP_SEQ_CHECK(x)       do { } while (0)
  343 #endif
  344 
  345 /* Whether to use m_copypacket() or m_dup() */
  346 #define L2TP_COPY_MBUF          m_copypacket
  347 
  348 #define ERROUT(x)       do { error = (x); goto done; } while (0)
  349 
  350 /************************************************************************
  351                         NETGRAPH NODE STUFF
  352 ************************************************************************/
  353 
  354 /*
  355  * Node type constructor
  356  */
  357 static int
  358 ng_l2tp_constructor(node_p node)
  359 {
  360         priv_p priv;
  361         int     i;
  362 
  363         /* Allocate private structure */
  364         priv = malloc(sizeof(*priv), M_NETGRAPH_L2TP, M_WAITOK | M_ZERO);
  365         NG_NODE_SET_PRIVATE(node, priv);
  366         priv->node = node;
  367 
  368         /* Apply a semi-reasonable default configuration */
  369         priv->conf.peer_win = 1;
  370         priv->conf.rexmit_max = L2TP_MAX_REXMIT;
  371         priv->conf.rexmit_max_to = L2TP_MAX_REXMIT_TO;
  372 
  373         /* Initialize sequence number state */
  374         ng_l2tp_seq_init(priv);
  375 
  376         for (i = 0; i < SESSHASHSIZE; i++)
  377             LIST_INIT(&priv->sesshash[i]);
  378 
  379         /* Done */
  380         return (0);
  381 }
  382 
  383 /*
  384  * Give our OK for a hook to be added.
  385  */
  386 static int
  387 ng_l2tp_newhook(node_p node, hook_p hook, const char *name)
  388 {
  389         const priv_p priv = NG_NODE_PRIVATE(node);
  390 
  391         /* Check hook name */
  392         if (strcmp(name, NG_L2TP_HOOK_CTRL) == 0) {
  393                 if (priv->ctrl != NULL)
  394                         return (EISCONN);
  395                 priv->ctrl = hook;
  396                 NG_HOOK_SET_RCVDATA(hook, ng_l2tp_rcvdata_ctrl);
  397         } else if (strcmp(name, NG_L2TP_HOOK_LOWER) == 0) {
  398                 if (priv->lower != NULL)
  399                         return (EISCONN);
  400                 priv->lower = hook;
  401                 NG_HOOK_SET_RCVDATA(hook, ng_l2tp_rcvdata_lower);
  402         } else {
  403                 static const char hexdig[16] = "0123456789abcdef";
  404                 u_int16_t session_id;
  405                 hookpriv_p hpriv;
  406                 uint16_t hash;
  407                 const char *hex;
  408                 int i;
  409                 int j;
  410 
  411                 /* Parse hook name to get session ID */
  412                 if (strncmp(name, NG_L2TP_HOOK_SESSION_P,
  413                     sizeof(NG_L2TP_HOOK_SESSION_P) - 1) != 0)
  414                         return (EINVAL);
  415                 hex = name + sizeof(NG_L2TP_HOOK_SESSION_P) - 1;
  416                 for (session_id = i = 0; i < 4; i++) {
  417                         for (j = 0; j < 16 && hex[i] != hexdig[j]; j++);
  418                         if (j == 16)
  419                                 return (EINVAL);
  420                         session_id = (session_id << 4) | j;
  421                 }
  422                 if (hex[i] != '\0')
  423                         return (EINVAL);
  424 
  425                 /* Create hook private structure */
  426                 hpriv = malloc(sizeof(*hpriv),
  427                     M_NETGRAPH_L2TP, M_NOWAIT | M_ZERO);
  428                 if (hpriv == NULL)
  429                         return (ENOMEM);
  430                 hpriv->conf.session_id = session_id;
  431                 hpriv->conf.control_dseq = L2TP_CONTROL_DSEQ;
  432                 hpriv->conf.enable_dseq = L2TP_ENABLE_DSEQ;
  433                 hpriv->hook = hook;
  434                 NG_HOOK_SET_PRIVATE(hook, hpriv);
  435                 hash = SESSHASH(hpriv->conf.session_id);
  436                 LIST_INSERT_HEAD(&priv->sesshash[hash], hpriv, sessions);
  437         }
  438 
  439         /* Done */
  440         return (0);
  441 }
  442 
  443 /*
  444  * Receive a control message.
  445  */
  446 static int
  447 ng_l2tp_rcvmsg(node_p node, item_p item, hook_p lasthook)
  448 {
  449         const priv_p priv = NG_NODE_PRIVATE(node);
  450         struct ng_mesg *resp = NULL;
  451         struct ng_mesg *msg;
  452         int error = 0;
  453 
  454         NGI_GET_MSG(item, msg);
  455         switch (msg->header.typecookie) {
  456         case NGM_L2TP_COOKIE:
  457                 switch (msg->header.cmd) {
  458                 case NGM_L2TP_SET_CONFIG:
  459                     {
  460                         struct ng_l2tp_config *const conf =
  461                                 (struct ng_l2tp_config *)msg->data;
  462 
  463                         /* Check for invalid or illegal config */
  464                         if (msg->header.arglen != sizeof(*conf)) {
  465                                 error = EINVAL;
  466                                 break;
  467                         }
  468                         conf->enabled = !!conf->enabled;
  469                         conf->match_id = !!conf->match_id;
  470                         if (priv->conf.enabled
  471                             && ((priv->conf.tunnel_id != 0
  472                                && conf->tunnel_id != priv->conf.tunnel_id)
  473                               || ((priv->conf.peer_id != 0
  474                                && conf->peer_id != priv->conf.peer_id)))) {
  475                                 error = EBUSY;
  476                                 break;
  477                         }
  478 
  479                         /* Save calling node as failure target */
  480                         priv->ftarget = NGI_RETADDR(item);
  481 
  482                         /* Adjust sequence number state */
  483                         if ((error = ng_l2tp_seq_adjust(priv, conf)) != 0)
  484                                 break;
  485 
  486                         /* Update node's config */
  487                         priv->conf = *conf;
  488                         break;
  489                     }
  490                 case NGM_L2TP_GET_CONFIG:
  491                     {
  492                         struct ng_l2tp_config *conf;
  493 
  494                         NG_MKRESPONSE(resp, msg, sizeof(*conf), M_NOWAIT);
  495                         if (resp == NULL) {
  496                                 error = ENOMEM;
  497                                 break;
  498                         }
  499                         conf = (struct ng_l2tp_config *)resp->data;
  500                         *conf = priv->conf;
  501                         break;
  502                     }
  503                 case NGM_L2TP_SET_SESS_CONFIG:
  504                     {
  505                         struct ng_l2tp_sess_config *const conf =
  506                             (struct ng_l2tp_sess_config *)msg->data;
  507                         hookpriv_p hpriv;
  508 
  509                         /* Check for invalid or illegal config. */
  510                         if (msg->header.arglen != sizeof(*conf)) {
  511                                 error = EINVAL;
  512                                 break;
  513                         }
  514 
  515                         /* Find matching hook */
  516                         hpriv = ng_l2tp_find_session(priv, conf->session_id);
  517                         if (hpriv == NULL) {
  518                                 error = ENOENT;
  519                                 break;
  520                         }
  521 
  522                         /* Update hook's config */
  523                         hpriv->conf = *conf;
  524                         break;
  525                     }
  526                 case NGM_L2TP_GET_SESS_CONFIG:
  527                     {
  528                         struct ng_l2tp_sess_config *conf;
  529                         u_int16_t session_id;
  530                         hookpriv_p hpriv;
  531 
  532                         /* Get session ID */
  533                         if (msg->header.arglen != sizeof(session_id)) {
  534                                 error = EINVAL;
  535                                 break;
  536                         }
  537                         memcpy(&session_id, msg->data, 2);
  538 
  539                         /* Find matching hook */
  540                         hpriv = ng_l2tp_find_session(priv, session_id);
  541                         if (hpriv == NULL) {
  542                                 error = ENOENT;
  543                                 break;
  544                         }
  545 
  546                         /* Send response */
  547                         NG_MKRESPONSE(resp, msg, sizeof(hpriv->conf), M_NOWAIT);
  548                         if (resp == NULL) {
  549                                 error = ENOMEM;
  550                                 break;
  551                         }
  552                         conf = (struct ng_l2tp_sess_config *)resp->data;
  553                         *conf = hpriv->conf;
  554                         break;
  555                     }
  556                 case NGM_L2TP_GET_STATS:
  557                 case NGM_L2TP_CLR_STATS:
  558                 case NGM_L2TP_GETCLR_STATS:
  559                     {
  560                         if (msg->header.cmd != NGM_L2TP_CLR_STATS) {
  561                                 NG_MKRESPONSE(resp, msg,
  562                                     sizeof(priv->stats), M_NOWAIT);
  563                                 if (resp == NULL) {
  564                                         error = ENOMEM;
  565                                         break;
  566                                 }
  567                                 memcpy(resp->data,
  568                                     &priv->stats, sizeof(priv->stats));
  569                         }
  570                         if (msg->header.cmd != NGM_L2TP_GET_STATS)
  571                                 memset(&priv->stats, 0, sizeof(priv->stats));
  572                         break;
  573                     }
  574                 case NGM_L2TP_GET_SESSION_STATS:
  575                 case NGM_L2TP_CLR_SESSION_STATS:
  576                 case NGM_L2TP_GETCLR_SESSION_STATS:
  577                     {
  578                         uint16_t session_id;
  579                         hookpriv_p hpriv;
  580 
  581                         /* Get session ID. */
  582                         if (msg->header.arglen != sizeof(session_id)) {
  583                                 error = EINVAL;
  584                                 break;
  585                         }
  586                         bcopy(msg->data, &session_id, sizeof(uint16_t));
  587 
  588                         /* Find matching hook. */
  589                         hpriv = ng_l2tp_find_session(priv, session_id);
  590                         if (hpriv == NULL) {
  591                                 error = ENOENT;
  592                                 break;
  593                         }
  594 
  595                         if (msg->header.cmd != NGM_L2TP_CLR_SESSION_STATS) {
  596                                 NG_MKRESPONSE(resp, msg,
  597                                     sizeof(hpriv->stats), M_NOWAIT);
  598                                 if (resp == NULL) {
  599                                         error = ENOMEM;
  600                                         break;
  601                                 }
  602                                 bcopy(&hpriv->stats, resp->data,
  603                                         sizeof(hpriv->stats));
  604                         }
  605                         if (msg->header.cmd != NGM_L2TP_GET_SESSION_STATS)
  606                                 bzero(&hpriv->stats, sizeof(hpriv->stats));
  607                         break;
  608                     }
  609                 case NGM_L2TP_SET_SEQ:
  610                     {
  611                         struct ng_l2tp_seq_config *const conf =
  612                                 (struct ng_l2tp_seq_config *)msg->data;
  613 
  614                         /* Check for invalid or illegal seq config. */
  615                         if (msg->header.arglen != sizeof(*conf)) {
  616                                 error = EINVAL;
  617                                 break;
  618                         }
  619                         conf->ns = htons(conf->ns);
  620                         conf->nr = htons(conf->nr);
  621                         conf->rack = htons(conf->rack);
  622                         conf->xack = htons(conf->xack);
  623 
  624                         /* Set sequence numbers. */
  625                         error = ng_l2tp_seq_set(priv, conf);
  626                         break;
  627                     }
  628                 default:
  629                         error = EINVAL;
  630                         break;
  631                 }
  632                 break;
  633         default:
  634                 error = EINVAL;
  635                 break;
  636         }
  637 
  638         /* Done */
  639         NG_RESPOND_MSG(error, node, item, resp);
  640         NG_FREE_MSG(msg);
  641         return (error);
  642 }
  643 
  644 /*
  645  * Destroy node
  646  */
  647 static int
  648 ng_l2tp_shutdown(node_p node)
  649 {
  650         const priv_p priv = NG_NODE_PRIVATE(node);
  651         struct l2tp_seq *const seq = &priv->seq;
  652 
  653         /* Sanity check */
  654         L2TP_SEQ_CHECK(seq);
  655 
  656         /* Reset sequence number state */
  657         ng_l2tp_seq_reset(priv);
  658 
  659         /* Free private data if neither timer is running */
  660         ng_uncallout(&seq->rack_timer, node);
  661         ng_uncallout(&seq->xack_timer, node);
  662 
  663         mtx_destroy(&seq->mtx);
  664 
  665         free(priv, M_NETGRAPH_L2TP);
  666 
  667         /* Unref node */
  668         NG_NODE_UNREF(node);
  669         return (0);
  670 }
  671 
  672 /*
  673  * Hook disconnection
  674  */
  675 static int
  676 ng_l2tp_disconnect(hook_p hook)
  677 {
  678         const node_p node = NG_HOOK_NODE(hook);
  679         const priv_p priv = NG_NODE_PRIVATE(node);
  680 
  681         /* Zero out hook pointer */
  682         if (hook == priv->ctrl)
  683                 priv->ctrl = NULL;
  684         else if (hook == priv->lower)
  685                 priv->lower = NULL;
  686         else {
  687                 const hookpriv_p hpriv = NG_HOOK_PRIVATE(hook);
  688                 LIST_REMOVE(hpriv, sessions);
  689                 free(hpriv, M_NETGRAPH_L2TP);
  690                 NG_HOOK_SET_PRIVATE(hook, NULL);
  691         }
  692 
  693         /* Go away if no longer connected to anything */
  694         if (NG_NODE_NUMHOOKS(node) == 0 && NG_NODE_IS_VALID(node))
  695                 ng_rmnode_self(node);
  696         return (0);
  697 }
  698 
  699 /*************************************************************************
  700                         INTERNAL FUNCTIONS
  701 *************************************************************************/
  702 
  703 /*
  704  * Find the hook with a given session ID.
  705  */
  706 static hookpriv_p
  707 ng_l2tp_find_session(priv_p privp, u_int16_t sid)
  708 {
  709         uint16_t        hash = SESSHASH(sid);
  710         hookpriv_p      hpriv = NULL;
  711 
  712         LIST_FOREACH(hpriv, &privp->sesshash[hash], sessions) {
  713                 if (hpriv->conf.session_id == sid)
  714                         break;
  715         }
  716 
  717         return (hpriv);
  718 }
  719 
  720 /*
  721  * Reset a hook's session state.
  722  */
  723 static int
  724 ng_l2tp_reset_session(hook_p hook, void *arg)
  725 {
  726         const hookpriv_p hpriv = NG_HOOK_PRIVATE(hook);
  727 
  728         if (hpriv != NULL) {
  729                 hpriv->conf.control_dseq = 0;
  730                 hpriv->conf.enable_dseq = 0;
  731                 bzero(&hpriv->stats, sizeof(struct ng_l2tp_session_stats));
  732                 hpriv->nr = 0;
  733                 hpriv->ns = 0;
  734         }
  735         return (-1);
  736 }
  737 
  738 /*
  739  * Handle an incoming frame from below.
  740  */
  741 static int
  742 ng_l2tp_rcvdata_lower(hook_p h, item_p item)
  743 {
  744         static const u_int16_t req_bits[2][2] = {
  745                 { L2TP_DATA_0BITS, L2TP_DATA_1BITS },
  746                 { L2TP_CTRL_0BITS, L2TP_CTRL_1BITS },
  747         };
  748         const node_p node = NG_HOOK_NODE(h);
  749         const priv_p priv = NG_NODE_PRIVATE(node);
  750         hookpriv_p hpriv = NULL;
  751         hook_p hook = NULL;
  752         struct mbuf *m;
  753         u_int16_t tid, sid;
  754         u_int16_t hdr;
  755         u_int16_t ns, nr;
  756         int is_ctrl;
  757         int error;
  758         int len, plen;
  759 
  760         /* Sanity check */
  761         L2TP_SEQ_CHECK(&priv->seq);
  762 
  763         /* If not configured, reject */
  764         if (!priv->conf.enabled) {
  765                 NG_FREE_ITEM(item);
  766                 ERROUT(ENXIO);
  767         }
  768 
  769         /* Grab mbuf */
  770         NGI_GET_M(item, m);
  771 
  772         /* Remember full packet length; needed for per session accounting. */
  773         plen = m->m_pkthdr.len;
  774 
  775         /* Update stats */
  776         priv->stats.recvPackets++;
  777         priv->stats.recvOctets += plen;
  778 
  779         /* Get initial header */
  780         if (m->m_pkthdr.len < 6) {
  781                 priv->stats.recvRunts++;
  782                 NG_FREE_ITEM(item);
  783                 NG_FREE_M(m);
  784                 ERROUT(EINVAL);
  785         }
  786         if (m->m_len < 2 && (m = m_pullup(m, 2)) == NULL) {
  787                 priv->stats.memoryFailures++;
  788                 NG_FREE_ITEM(item);
  789                 ERROUT(EINVAL);
  790         }
  791         hdr = (mtod(m, uint8_t *)[0] << 8) + mtod(m, uint8_t *)[1];
  792         m_adj(m, 2);
  793 
  794         /* Check required header bits and minimum length */
  795         is_ctrl = (hdr & L2TP_HDR_CTRL) != 0;
  796         if ((hdr & req_bits[is_ctrl][0]) != 0
  797             || (~hdr & req_bits[is_ctrl][1]) != 0) {
  798                 priv->stats.recvInvalid++;
  799                 NG_FREE_ITEM(item);
  800                 NG_FREE_M(m);
  801                 ERROUT(EINVAL);
  802         }
  803         if (m->m_pkthdr.len < 4                         /* tunnel, session id */
  804             + (2 * ((hdr & L2TP_HDR_LEN) != 0))         /* length field */
  805             + (4 * ((hdr & L2TP_HDR_SEQ) != 0))         /* seq # fields */
  806             + (2 * ((hdr & L2TP_HDR_OFF) != 0))) {      /* offset field */
  807                 priv->stats.recvRunts++;
  808                 NG_FREE_ITEM(item);
  809                 NG_FREE_M(m);
  810                 ERROUT(EINVAL);
  811         }
  812 
  813         /* Get and validate length field if present */
  814         if ((hdr & L2TP_HDR_LEN) != 0) {
  815                 if (m->m_len < 2 && (m = m_pullup(m, 2)) == NULL) {
  816                         priv->stats.memoryFailures++;
  817                         NG_FREE_ITEM(item);
  818                         ERROUT(EINVAL);
  819                 }
  820                 len = (mtod(m, uint8_t *)[0] << 8) + mtod(m, uint8_t *)[1] - 4;
  821                 m_adj(m, 2);
  822                 if (len < 0 || len > m->m_pkthdr.len) {
  823                         priv->stats.recvInvalid++;
  824                         NG_FREE_ITEM(item);
  825                         NG_FREE_M(m);
  826                         ERROUT(EINVAL);
  827                 }
  828                 if (len < m->m_pkthdr.len)              /* trim extra bytes */
  829                         m_adj(m, -(m->m_pkthdr.len - len));
  830         }
  831 
  832         /* Get tunnel ID and session ID */
  833         if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL) {
  834                 priv->stats.memoryFailures++;
  835                 NG_FREE_ITEM(item);
  836                 ERROUT(EINVAL);
  837         }
  838         tid = (mtod(m, u_int8_t *)[0] << 8) + mtod(m, u_int8_t *)[1];
  839         sid = (mtod(m, u_int8_t *)[2] << 8) + mtod(m, u_int8_t *)[3];
  840         m_adj(m, 4);
  841 
  842         /* Check tunnel ID */
  843         if (tid != priv->conf.tunnel_id &&
  844             (priv->conf.match_id || tid != 0)) {
  845                 priv->stats.recvWrongTunnel++;
  846                 NG_FREE_ITEM(item);
  847                 NG_FREE_M(m);
  848                 ERROUT(EADDRNOTAVAIL);
  849         }
  850 
  851         /* Check session ID (for data packets only) */
  852         if ((hdr & L2TP_HDR_CTRL) == 0) {
  853                 hpriv = ng_l2tp_find_session(priv, sid);
  854                 if (hpriv == NULL) {
  855                         priv->stats.recvUnknownSID++;
  856                         NG_FREE_ITEM(item);
  857                         NG_FREE_M(m);
  858                         ERROUT(ENOTCONN);
  859                 }
  860                 hook = hpriv->hook;
  861         }
  862 
  863         /* Get Ns, Nr fields if present */
  864         if ((hdr & L2TP_HDR_SEQ) != 0) {
  865                 if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL) {
  866                         priv->stats.memoryFailures++;
  867                         NG_FREE_ITEM(item);
  868                         ERROUT(EINVAL);
  869                 }
  870                 ns = (mtod(m, u_int8_t *)[0] << 8) + mtod(m, u_int8_t *)[1];
  871                 nr = (mtod(m, u_int8_t *)[2] << 8) + mtod(m, u_int8_t *)[3];
  872                 m_adj(m, 4);
  873         } else
  874                 ns = nr = 0;
  875 
  876         /* Strip offset padding if present */
  877         if ((hdr & L2TP_HDR_OFF) != 0) {
  878                 u_int16_t offset;
  879 
  880                 /* Get length of offset padding */
  881                 if (m->m_len < 2 && (m = m_pullup(m, 2)) == NULL) {
  882                         priv->stats.memoryFailures++;
  883                         NG_FREE_ITEM(item);
  884                         ERROUT(EINVAL);
  885                 }
  886                 offset = (mtod(m, u_int8_t *)[0] << 8) + mtod(m, u_int8_t *)[1];
  887 
  888                 /* Trim offset padding */
  889                 if ((2+offset) > m->m_pkthdr.len) {
  890                         priv->stats.recvInvalid++;
  891                         NG_FREE_ITEM(item);
  892                         NG_FREE_M(m);
  893                         ERROUT(EINVAL);
  894                 }
  895                 m_adj(m, 2+offset);
  896         }
  897 
  898         /* Handle control packets */
  899         if ((hdr & L2TP_HDR_CTRL) != 0) {
  900                 struct l2tp_seq *const seq = &priv->seq;
  901 
  902                 /* Handle receive ack sequence number Nr */
  903                 ng_l2tp_seq_recv_nr(priv, nr);
  904 
  905                 /* Discard ZLB packets */
  906                 if (m->m_pkthdr.len == 0) {
  907                         priv->stats.recvZLBs++;
  908                         NG_FREE_ITEM(item);
  909                         NG_FREE_M(m);
  910                         ERROUT(0);
  911                 }
  912 
  913                 mtx_lock(&seq->mtx);
  914                 /*
  915                  * If not what we expect or we are busy, drop packet and
  916                  * send an immediate ZLB ack.
  917                  */
  918                 if (ns != seq->nr || seq->inproc) {
  919                         if (L2TP_SEQ_DIFF(ns, seq->nr) <= 0)
  920                                 priv->stats.recvDuplicates++;
  921                         else
  922                                 priv->stats.recvOutOfOrder++;
  923                         mtx_unlock(&seq->mtx);
  924                         ng_l2tp_xmit_ctrl(priv, NULL, seq->ns);
  925                         NG_FREE_ITEM(item);
  926                         NG_FREE_M(m);
  927                         ERROUT(0);
  928                 }
  929                 /*
  930                  * Until we deliver this packet we can't receive next one as
  931                  * we have no information for sending ack.
  932                  */
  933                 seq->inproc = 1;
  934                 mtx_unlock(&seq->mtx);
  935 
  936                 /* Prepend session ID to packet. */
  937                 M_PREPEND(m, 2, M_NOWAIT);
  938                 if (m == NULL) {
  939                         seq->inproc = 0;
  940                         priv->stats.memoryFailures++;
  941                         NG_FREE_ITEM(item);
  942                         ERROUT(ENOBUFS);
  943                 }
  944                 mtod(m, u_int8_t *)[0] = sid >> 8;
  945                 mtod(m, u_int8_t *)[1] = sid & 0xff;
  946 
  947                 /* Deliver packet to upper layers */
  948                 NG_FWD_NEW_DATA(error, item, priv->ctrl, m);
  949                 
  950                 mtx_lock(&seq->mtx);
  951                 /* Ready to process next packet. */
  952                 seq->inproc = 0;
  953 
  954                 /* If packet was successfully delivered send ack. */
  955                 if (error == 0) {
  956                         /* Update recv sequence number */
  957                         seq->nr++;
  958                         /* Start receive ack timer, if not already running */
  959                         if (!callout_active(&seq->xack_timer)) {
  960                                 ng_callout(&seq->xack_timer, priv->node, NULL,
  961                                     L2TP_DELAYED_ACK, ng_l2tp_seq_xack_timeout,
  962                                     NULL, 0);
  963                         }
  964                 }
  965                 mtx_unlock(&seq->mtx);
  966 
  967                 ERROUT(error);
  968         }
  969 
  970         /* Per session packet, account it. */
  971         hpriv->stats.recvPackets++;
  972         hpriv->stats.recvOctets += plen;
  973 
  974         /* Follow peer's lead in data sequencing, if configured to do so */
  975         if (!hpriv->conf.control_dseq)
  976                 hpriv->conf.enable_dseq = ((hdr & L2TP_HDR_SEQ) != 0);
  977 
  978         /* Handle data sequence numbers if present and enabled */
  979         if ((hdr & L2TP_HDR_SEQ) != 0) {
  980                 if (hpriv->conf.enable_dseq
  981                     && L2TP_SEQ_DIFF(ns, hpriv->nr) < 0) {
  982                         NG_FREE_ITEM(item);     /* duplicate or out of order */
  983                         NG_FREE_M(m);
  984                         priv->stats.recvDataDrops++;
  985                         ERROUT(0);
  986                 }
  987                 hpriv->nr = ns + 1;
  988         }
  989 
  990         /* Drop empty data packets */
  991         if (m->m_pkthdr.len == 0) {
  992                 NG_FREE_ITEM(item);
  993                 NG_FREE_M(m);
  994                 ERROUT(0);
  995         }
  996 
  997         /* Deliver data */
  998         NG_FWD_NEW_DATA(error, item, hook, m);
  999 done:
 1000         /* Done */
 1001         L2TP_SEQ_CHECK(&priv->seq);
 1002         return (error);
 1003 }
 1004 
 1005 /*
 1006  * Handle an outgoing control frame.
 1007  */
 1008 static int
 1009 ng_l2tp_rcvdata_ctrl(hook_p hook, item_p item)
 1010 {
 1011         const node_p node = NG_HOOK_NODE(hook);
 1012         const priv_p priv = NG_NODE_PRIVATE(node);
 1013         struct l2tp_seq *const seq = &priv->seq;
 1014         struct mbuf *m;
 1015         int error;
 1016         int i;
 1017         u_int16_t       ns;
 1018 
 1019         /* Sanity check */
 1020         L2TP_SEQ_CHECK(&priv->seq);
 1021 
 1022         /* If not configured, reject */
 1023         if (!priv->conf.enabled) {
 1024                 NG_FREE_ITEM(item);
 1025                 ERROUT(ENXIO);
 1026         }
 1027 
 1028         /* Grab mbuf and discard other stuff XXX */
 1029         NGI_GET_M(item, m);
 1030         NG_FREE_ITEM(item);
 1031 
 1032         /* Packet should have session ID prepended */
 1033         if (m->m_pkthdr.len < 2) {
 1034                 priv->stats.xmitInvalid++;
 1035                 m_freem(m);
 1036                 ERROUT(EINVAL);
 1037         }
 1038 
 1039         /* Check max length */
 1040         if (m->m_pkthdr.len >= 0x10000 - 14) {
 1041                 priv->stats.xmitTooBig++;
 1042                 m_freem(m);
 1043                 ERROUT(EOVERFLOW);
 1044         }
 1045 
 1046         mtx_lock(&seq->mtx);
 1047 
 1048         /* Find next empty slot in transmit queue */
 1049         for (i = 0; i < L2TP_MAX_XWIN && seq->xwin[i] != NULL; i++);
 1050         if (i == L2TP_MAX_XWIN) {
 1051                 mtx_unlock(&seq->mtx);
 1052                 priv->stats.xmitDrops++;
 1053                 m_freem(m);
 1054                 ERROUT(ENOBUFS);
 1055         }
 1056         seq->xwin[i] = m;
 1057 
 1058         /* If peer's receive window is already full, nothing else to do */
 1059         if (i >= seq->cwnd) {
 1060                 mtx_unlock(&seq->mtx);
 1061                 ERROUT(0);
 1062         }
 1063 
 1064         /* Start retransmit timer if not already running */
 1065         if (!callout_active(&seq->rack_timer))
 1066                 ng_callout(&seq->rack_timer, node, NULL,
 1067                     hz, ng_l2tp_seq_rack_timeout, NULL, 0);
 1068         
 1069         ns = seq->ns++;
 1070         
 1071         mtx_unlock(&seq->mtx);
 1072 
 1073         /* Copy packet */
 1074         if ((m = L2TP_COPY_MBUF(m, M_NOWAIT)) == NULL) {
 1075                 priv->stats.memoryFailures++;
 1076                 ERROUT(ENOBUFS);
 1077         }
 1078 
 1079         /* Send packet and increment xmit sequence number */
 1080         error = ng_l2tp_xmit_ctrl(priv, m, ns);
 1081 done:
 1082         /* Done */
 1083         L2TP_SEQ_CHECK(&priv->seq);
 1084         return (error);
 1085 }
 1086 
 1087 /*
 1088  * Handle an outgoing data frame.
 1089  */
 1090 static int
 1091 ng_l2tp_rcvdata(hook_p hook, item_p item)
 1092 {
 1093         const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
 1094         const hookpriv_p hpriv = NG_HOOK_PRIVATE(hook);
 1095         struct mbuf *m;
 1096         uint8_t *p;
 1097         u_int16_t hdr;
 1098         int error;
 1099         int i = 2;
 1100 
 1101         /* Sanity check */
 1102         L2TP_SEQ_CHECK(&priv->seq);
 1103 
 1104         /* If not configured, reject */
 1105         if (!priv->conf.enabled) {
 1106                 NG_FREE_ITEM(item);
 1107                 ERROUT(ENXIO);
 1108         }
 1109 
 1110         /* Get mbuf */
 1111         NGI_GET_M(item, m);
 1112 
 1113         /* Check max length */
 1114         if (m->m_pkthdr.len >= 0x10000 - 12) {
 1115                 priv->stats.xmitDataTooBig++;
 1116                 NG_FREE_ITEM(item);
 1117                 NG_FREE_M(m);
 1118                 ERROUT(EOVERFLOW);
 1119         }
 1120 
 1121         /* Prepend L2TP header */
 1122         M_PREPEND(m, 6
 1123             + (2 * (hpriv->conf.include_length != 0))
 1124             + (4 * (hpriv->conf.enable_dseq != 0)),
 1125             M_NOWAIT);
 1126         if (m == NULL) {
 1127                 priv->stats.memoryFailures++;
 1128                 NG_FREE_ITEM(item);
 1129                 ERROUT(ENOBUFS);
 1130         }
 1131         p = mtod(m, uint8_t *);
 1132         hdr = L2TP_DATA_HDR;
 1133         if (hpriv->conf.include_length) {
 1134                 hdr |= L2TP_HDR_LEN;
 1135                 p[i++] = m->m_pkthdr.len >> 8;
 1136                 p[i++] = m->m_pkthdr.len & 0xff;
 1137         }
 1138         p[i++] = priv->conf.peer_id >> 8;
 1139         p[i++] = priv->conf.peer_id & 0xff;
 1140         p[i++] = hpriv->conf.peer_id >> 8;
 1141         p[i++] = hpriv->conf.peer_id & 0xff;
 1142         if (hpriv->conf.enable_dseq) {
 1143                 hdr |= L2TP_HDR_SEQ;
 1144                 p[i++] = hpriv->ns >> 8;
 1145                 p[i++] = hpriv->ns & 0xff;
 1146                 p[i++] = hpriv->nr >> 8;
 1147                 p[i++] = hpriv->nr & 0xff;
 1148                 hpriv->ns++;
 1149         }
 1150         p[0] = hdr >> 8;
 1151         p[1] = hdr & 0xff;
 1152 
 1153         /* Update per session stats. */
 1154         hpriv->stats.xmitPackets++;
 1155         hpriv->stats.xmitOctets += m->m_pkthdr.len;
 1156 
 1157         /* And the global one. */
 1158         priv->stats.xmitPackets++;
 1159         priv->stats.xmitOctets += m->m_pkthdr.len;
 1160 
 1161         /* Send packet */
 1162         NG_FWD_NEW_DATA(error, item, priv->lower, m);
 1163 done:
 1164         /* Done */
 1165         L2TP_SEQ_CHECK(&priv->seq);
 1166         return (error);
 1167 }
 1168 
 1169 /*
 1170  * Send a message to our controlling node that we've failed.
 1171  */
 1172 static void
 1173 ng_l2tp_seq_failure(priv_p priv)
 1174 {
 1175         struct ng_mesg *msg;
 1176         int error;
 1177 
 1178         NG_MKMESSAGE(msg, NGM_L2TP_COOKIE, NGM_L2TP_ACK_FAILURE, 0, M_NOWAIT);
 1179         if (msg == NULL)
 1180                 return;
 1181         NG_SEND_MSG_ID(error, priv->node, msg, priv->ftarget, 0);
 1182 }
 1183 
 1184 /************************************************************************
 1185                         SEQUENCE NUMBER HANDLING
 1186 ************************************************************************/
 1187 
 1188 /*
 1189  * Initialize sequence number state.
 1190  */
 1191 static void
 1192 ng_l2tp_seq_init(priv_p priv)
 1193 {
 1194         struct l2tp_seq *const seq = &priv->seq;
 1195 
 1196         KASSERT(priv->conf.peer_win >= 1,
 1197             ("%s: peer_win is zero", __func__));
 1198         memset(seq, 0, sizeof(*seq));
 1199         seq->cwnd = 1;
 1200         seq->wmax = priv->conf.peer_win;
 1201         if (seq->wmax > L2TP_MAX_XWIN)
 1202                 seq->wmax = L2TP_MAX_XWIN;
 1203         seq->ssth = seq->wmax;
 1204         ng_callout_init(&seq->rack_timer);
 1205         ng_callout_init(&seq->xack_timer);
 1206         mtx_init(&seq->mtx, "ng_l2tp", NULL, MTX_DEF);
 1207         L2TP_SEQ_CHECK(seq);
 1208 }
 1209 
 1210 /*
 1211  * Set sequence number state as given from user.
 1212  */
 1213 static int
 1214 ng_l2tp_seq_set(priv_p priv, const struct ng_l2tp_seq_config *conf)
 1215 {
 1216         struct l2tp_seq *const seq = &priv->seq;
 1217 
 1218         /* If node is enabled, deny update to sequence numbers. */
 1219         if (priv->conf.enabled)
 1220                 return (EBUSY);
 1221 
 1222         /* We only can handle the simple cases. */
 1223         if (conf->xack != conf->nr || conf->ns != conf->rack)
 1224                 return (EINVAL);
 1225 
 1226         /* Set ns,nr,rack,xack parameters. */
 1227         seq->ns = conf->ns;
 1228         seq->nr = conf->nr;
 1229         seq->rack = conf->rack;
 1230         seq->xack = conf->xack;
 1231 
 1232         return (0);
 1233 }
 1234 
 1235 /*
 1236  * Adjust sequence number state accordingly after reconfiguration.
 1237  */
 1238 static int
 1239 ng_l2tp_seq_adjust(priv_p priv, const struct ng_l2tp_config *conf)
 1240 {
 1241         struct l2tp_seq *const seq = &priv->seq;
 1242         u_int16_t new_wmax;
 1243 
 1244         /* If disabling node, reset state sequence number */
 1245         if (!conf->enabled) {
 1246                 ng_l2tp_seq_reset(priv);
 1247                 return (0);
 1248         }
 1249 
 1250         /* Adjust peer's max recv window; it can only increase */
 1251         new_wmax = conf->peer_win;
 1252         if (new_wmax > L2TP_MAX_XWIN)
 1253                 new_wmax = L2TP_MAX_XWIN;
 1254         if (new_wmax == 0)
 1255                 return (EINVAL);
 1256         if (new_wmax < seq->wmax)
 1257                 return (EBUSY);
 1258         seq->wmax = new_wmax;
 1259 
 1260         /* Done */
 1261         return (0);
 1262 }
 1263 
 1264 /*
 1265  * Reset sequence number state.
 1266  */
 1267 static void
 1268 ng_l2tp_seq_reset(priv_p priv)
 1269 {
 1270         struct l2tp_seq *const seq = &priv->seq;
 1271         hook_p hook;
 1272         int i;
 1273 
 1274         /* Sanity check */
 1275         L2TP_SEQ_CHECK(seq);
 1276 
 1277         /* Stop timers */
 1278         ng_uncallout(&seq->rack_timer, priv->node);
 1279         ng_uncallout(&seq->xack_timer, priv->node);
 1280 
 1281         /* Free retransmit queue */
 1282         for (i = 0; i < L2TP_MAX_XWIN; i++) {
 1283                 if (seq->xwin[i] == NULL)
 1284                         break;
 1285                 m_freem(seq->xwin[i]);
 1286         }
 1287 
 1288         /* Reset session hooks' sequence number states */
 1289         NG_NODE_FOREACH_HOOK(priv->node, ng_l2tp_reset_session, NULL, hook);
 1290 
 1291         /* Reset node's sequence number state */
 1292         seq->ns = 0;
 1293         seq->nr = 0;
 1294         seq->rack = 0;
 1295         seq->xack = 0;
 1296         seq->wmax = L2TP_MAX_XWIN;
 1297         seq->cwnd = 1;
 1298         seq->ssth = seq->wmax;
 1299         seq->acks = 0;
 1300         seq->rexmits = 0;
 1301         bzero(seq->xwin, sizeof(seq->xwin));
 1302 
 1303         /* Done */
 1304         L2TP_SEQ_CHECK(seq);
 1305 }
 1306 
 1307 /*
 1308  * Handle receipt of an acknowledgement value (Nr) from peer.
 1309  */
 1310 static void
 1311 ng_l2tp_seq_recv_nr(priv_p priv, u_int16_t nr)
 1312 {
 1313         struct l2tp_seq *const seq = &priv->seq;
 1314         struct mbuf     *xwin[L2TP_MAX_XWIN];   /* partial local copy */
 1315         int             nack;
 1316         int             i, j;
 1317         uint16_t        ns;
 1318 
 1319         mtx_lock(&seq->mtx);
 1320 
 1321         /* Verify peer's ACK is in range */
 1322         if ((nack = L2TP_SEQ_DIFF(nr, seq->rack)) <= 0) {
 1323                 mtx_unlock(&seq->mtx);
 1324                 return;                         /* duplicate ack */
 1325         }
 1326         if (L2TP_SEQ_DIFF(nr, seq->ns) > 0) {
 1327                 mtx_unlock(&seq->mtx);
 1328                 priv->stats.recvBadAcks++;      /* ack for packet not sent */
 1329                 return;
 1330         }
 1331         KASSERT(nack <= L2TP_MAX_XWIN,
 1332             ("%s: nack=%d > %d", __func__, nack, L2TP_MAX_XWIN));
 1333 
 1334         /* Update receive ack stats */
 1335         seq->rack = nr;
 1336         seq->rexmits = 0;
 1337 
 1338         /* Free acknowledged packets and shift up packets in the xmit queue */
 1339         for (i = 0; i < nack; i++)
 1340                 m_freem(seq->xwin[i]);
 1341         memmove(seq->xwin, seq->xwin + nack,
 1342             (L2TP_MAX_XWIN - nack) * sizeof(*seq->xwin));
 1343         memset(seq->xwin + (L2TP_MAX_XWIN - nack), 0,
 1344             nack * sizeof(*seq->xwin));
 1345 
 1346         /*
 1347          * Do slow-start/congestion avoidance windowing algorithm described
 1348          * in RFC 2661, Appendix A. Here we handle a multiple ACK as if each
 1349          * ACK had arrived separately.
 1350          */
 1351         if (seq->cwnd < seq->wmax) {
 1352 
 1353                 /* Handle slow start phase */
 1354                 if (seq->cwnd < seq->ssth) {
 1355                         seq->cwnd += nack;
 1356                         nack = 0;
 1357                         if (seq->cwnd > seq->ssth) {    /* into cg.av. phase */
 1358                                 nack = seq->cwnd - seq->ssth;
 1359                                 seq->cwnd = seq->ssth;
 1360                         }
 1361                 }
 1362 
 1363                 /* Handle congestion avoidance phase */
 1364                 if (seq->cwnd >= seq->ssth) {
 1365                         seq->acks += nack;
 1366                         while (seq->acks >= seq->cwnd) {
 1367                                 seq->acks -= seq->cwnd;
 1368                                 if (seq->cwnd < seq->wmax)
 1369                                         seq->cwnd++;
 1370                         }
 1371                 }
 1372         }
 1373 
 1374         /* Stop xmit timer */
 1375         if (callout_active(&seq->rack_timer))
 1376                 ng_uncallout(&seq->rack_timer, priv->node);
 1377 
 1378         /* If transmit queue is empty, we're done for now */
 1379         if (seq->xwin[0] == NULL) {
 1380                 mtx_unlock(&seq->mtx);
 1381                 return;
 1382         }
 1383 
 1384         /* Start restransmit timer again */
 1385         ng_callout(&seq->rack_timer, priv->node, NULL,
 1386             hz, ng_l2tp_seq_rack_timeout, NULL, 0);
 1387 
 1388         /*
 1389          * Send more packets, trying to keep peer's receive window full.
 1390          * Make copy of everything we need before lock release.
 1391          */
 1392         ns = seq->ns;
 1393         j = 0;
 1394         while ((i = L2TP_SEQ_DIFF(seq->ns, seq->rack)) < seq->cwnd
 1395             && seq->xwin[i] != NULL) {
 1396                 xwin[j++] = seq->xwin[i];
 1397                 seq->ns++;
 1398         }
 1399 
 1400         mtx_unlock(&seq->mtx);
 1401 
 1402         /*
 1403          * Send prepared.
 1404          * If there is a memory error, pretend packet was sent, as it
 1405          * will get retransmitted later anyway.
 1406          */
 1407         for (i = 0; i < j; i++) {
 1408                 struct mbuf     *m;
 1409                 if ((m = L2TP_COPY_MBUF(xwin[i], M_NOWAIT)) == NULL)
 1410                         priv->stats.memoryFailures++;
 1411                 else
 1412                         ng_l2tp_xmit_ctrl(priv, m, ns);
 1413                 ns++;
 1414         }
 1415 }
 1416 
 1417 /*
 1418  * Handle an ack timeout. We have an outstanding ack that we
 1419  * were hoping to piggy-back, but haven't, so send a ZLB.
 1420  */
 1421 static void
 1422 ng_l2tp_seq_xack_timeout(node_p node, hook_p hook, void *arg1, int arg2)
 1423 {
 1424         const priv_p priv = NG_NODE_PRIVATE(node);
 1425         struct l2tp_seq *const seq = &priv->seq;
 1426 
 1427         /* Make sure callout is still active before doing anything */
 1428         if (callout_pending(&seq->xack_timer) ||
 1429             (!callout_active(&seq->xack_timer)))
 1430                 return;
 1431 
 1432         /* Sanity check */
 1433         L2TP_SEQ_CHECK(seq);
 1434 
 1435         /* Send a ZLB */
 1436         ng_l2tp_xmit_ctrl(priv, NULL, seq->ns);
 1437 
 1438         /* callout_deactivate() is not needed here 
 1439             as ng_uncallout() was called by ng_l2tp_xmit_ctrl() */
 1440 
 1441         /* Sanity check */
 1442         L2TP_SEQ_CHECK(seq);
 1443 }
 1444 
 1445 /* 
 1446  * Handle a transmit timeout. The peer has failed to respond
 1447  * with an ack for our packet, so retransmit it.
 1448  */
 1449 static void
 1450 ng_l2tp_seq_rack_timeout(node_p node, hook_p hook, void *arg1, int arg2)
 1451 {
 1452         const priv_p priv = NG_NODE_PRIVATE(node);
 1453         struct l2tp_seq *const seq = &priv->seq;
 1454         struct mbuf *m;
 1455         u_int delay;
 1456 
 1457         /* Make sure callout is still active before doing anything */
 1458         if (callout_pending(&seq->rack_timer) ||
 1459             (!callout_active(&seq->rack_timer)))
 1460                 return;
 1461 
 1462         /* Sanity check */
 1463         L2TP_SEQ_CHECK(seq);
 1464 
 1465         priv->stats.xmitRetransmits++;
 1466 
 1467         /* Have we reached the retransmit limit? If so, notify owner. */
 1468         if (seq->rexmits++ >= priv->conf.rexmit_max)
 1469                 ng_l2tp_seq_failure(priv);
 1470 
 1471         /* Restart timer, this time with an increased delay */
 1472         delay = (seq->rexmits > 12) ? (1 << 12) : (1 << seq->rexmits);
 1473         if (delay > priv->conf.rexmit_max_to)
 1474                 delay = priv->conf.rexmit_max_to;
 1475         ng_callout(&seq->rack_timer, node, NULL,
 1476             hz * delay, ng_l2tp_seq_rack_timeout, NULL, 0);
 1477 
 1478         /* Do slow-start/congestion algorithm windowing algorithm */
 1479         seq->ns = seq->rack;
 1480         seq->ssth = (seq->cwnd + 1) / 2;
 1481         seq->cwnd = 1;
 1482         seq->acks = 0;
 1483 
 1484         /* Retransmit oldest unack'd packet */
 1485         if ((m = L2TP_COPY_MBUF(seq->xwin[0], M_NOWAIT)) == NULL)
 1486                 priv->stats.memoryFailures++;
 1487         else
 1488                 ng_l2tp_xmit_ctrl(priv, m, seq->ns++);
 1489 
 1490         /* callout_deactivate() is not needed here 
 1491             as ng_callout() is getting called each time */
 1492 
 1493         /* Sanity check */
 1494         L2TP_SEQ_CHECK(seq);
 1495 }
 1496 
 1497 /*
 1498  * Transmit a control stream packet, payload optional.
 1499  * The transmit sequence number is not incremented.
 1500  */
 1501 static int
 1502 ng_l2tp_xmit_ctrl(priv_p priv, struct mbuf *m, u_int16_t ns)
 1503 {
 1504         struct l2tp_seq *const seq = &priv->seq;
 1505         uint8_t *p;
 1506         u_int16_t session_id = 0;
 1507         int error;
 1508 
 1509         mtx_lock(&seq->mtx);
 1510 
 1511         /* Stop ack timer: we're sending an ack with this packet.
 1512            Doing this before to keep state predictable after error. */
 1513         if (callout_active(&seq->xack_timer))
 1514                 ng_uncallout(&seq->xack_timer, priv->node);
 1515 
 1516         seq->xack = seq->nr;
 1517 
 1518         mtx_unlock(&seq->mtx);
 1519 
 1520         /* If no mbuf passed, send an empty packet (ZLB) */
 1521         if (m == NULL) {
 1522 
 1523                 /* Create a new mbuf for ZLB packet */
 1524                 MGETHDR(m, M_NOWAIT, MT_DATA);
 1525                 if (m == NULL) {
 1526                         priv->stats.memoryFailures++;
 1527                         return (ENOBUFS);
 1528                 }
 1529                 m->m_len = m->m_pkthdr.len = 12;
 1530                 m->m_pkthdr.rcvif = NULL;
 1531                 priv->stats.xmitZLBs++;
 1532         } else {
 1533 
 1534                 /* Strip off session ID */
 1535                 if (m->m_len < 2 && (m = m_pullup(m, 2)) == NULL) {
 1536                         priv->stats.memoryFailures++;
 1537                         return (ENOBUFS);
 1538                 }
 1539                 session_id = (mtod(m, u_int8_t *)[0] << 8) + mtod(m, u_int8_t *)[1];
 1540 
 1541                 /* Make room for L2TP header */
 1542                 M_PREPEND(m, 10, M_NOWAIT);     /* - 2 + 12 = 10 */
 1543                 if (m == NULL) {
 1544                         priv->stats.memoryFailures++;
 1545                         return (ENOBUFS);
 1546                 }
 1547         }
 1548 
 1549         /* Fill in L2TP header */
 1550         p = mtod(m, u_int8_t *);
 1551         p[0] = L2TP_CTRL_HDR >> 8;
 1552         p[1] = L2TP_CTRL_HDR & 0xff;
 1553         p[2] = m->m_pkthdr.len >> 8;
 1554         p[3] = m->m_pkthdr.len & 0xff;
 1555         p[4] = priv->conf.peer_id >> 8;
 1556         p[5] = priv->conf.peer_id & 0xff;
 1557         p[6] = session_id >> 8;
 1558         p[7] = session_id & 0xff;
 1559         p[8] = ns >> 8;
 1560         p[9] = ns & 0xff;
 1561         p[10] = seq->nr >> 8;
 1562         p[11] = seq->nr & 0xff;
 1563 
 1564         /* Update sequence number info and stats */
 1565         priv->stats.xmitPackets++;
 1566         priv->stats.xmitOctets += m->m_pkthdr.len;
 1567 
 1568         /* Send packet */
 1569         NG_SEND_DATA_ONLY(error, priv->lower, m);
 1570         return (error);
 1571 }
 1572 
 1573 #ifdef INVARIANTS
 1574 /*
 1575  * Sanity check sequence number state.
 1576  */
 1577 static void
 1578 ng_l2tp_seq_check(struct l2tp_seq *seq)
 1579 {
 1580         int self_unack, peer_unack;
 1581         int i;
 1582 
 1583 #define CHECK(p)        KASSERT((p), ("%s: not: %s", __func__, #p))
 1584 
 1585         mtx_lock(&seq->mtx);
 1586 
 1587         self_unack = L2TP_SEQ_DIFF(seq->nr, seq->xack);
 1588         peer_unack = L2TP_SEQ_DIFF(seq->ns, seq->rack);
 1589         CHECK(seq->wmax <= L2TP_MAX_XWIN);
 1590         CHECK(seq->cwnd >= 1);
 1591         CHECK(seq->cwnd <= seq->wmax);
 1592         CHECK(seq->ssth >= 1);
 1593         CHECK(seq->ssth <= seq->wmax);
 1594         if (seq->cwnd < seq->ssth)
 1595                 CHECK(seq->acks == 0);
 1596         else
 1597                 CHECK(seq->acks <= seq->cwnd);
 1598         CHECK(self_unack >= 0);
 1599         CHECK(peer_unack >= 0);
 1600         CHECK(peer_unack <= seq->wmax);
 1601         CHECK((self_unack == 0) ^ callout_active(&seq->xack_timer));
 1602         CHECK((peer_unack == 0) ^ callout_active(&seq->rack_timer));
 1603         for (i = 0; i < peer_unack; i++)
 1604                 CHECK(seq->xwin[i] != NULL);
 1605         for ( ; i < seq->cwnd; i++)         /* verify peer's recv window full */
 1606                 CHECK(seq->xwin[i] == NULL);
 1607 
 1608         mtx_unlock(&seq->mtx);
 1609 
 1610 #undef CHECK
 1611 }
 1612 #endif  /* INVARIANTS */

Cache object: 4b9897ec6451b9ea04f61690b80ad280


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


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