ng_bpf.c

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    1 /*
    2  * ng_bpf.c
    3  */
    4 
    5 /*-
    6  * Copyright (c) 1999 Whistle Communications, Inc.
    7  * All rights reserved.
    8  * 
    9  * Subject to the following obligations and disclaimer of warranty, use and
   10  * redistribution of this software, in source or object code forms, with or
   11  * without modifications are expressly permitted by Whistle Communications;
   12  * provided, however, that:
   13  * 1. Any and all reproductions of the source or object code must include the
   14  *    copyright notice above and the following disclaimer of warranties; and
   15  * 2. No rights are granted, in any manner or form, to use Whistle
   16  *    Communications, Inc. trademarks, including the mark "WHISTLE
   17  *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
   18  *    such appears in the above copyright notice or in the software.
   19  * 
   20  * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
   21  * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
   22  * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
   23  * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
   24  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
   25  * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
   26  * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
   27  * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
   28  * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
   29  * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
   30  * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
   31  * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
   32  * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
   33  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   34  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   35  * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
   36  * OF SUCH DAMAGE.
   37  *
   38  * Author: Archie Cobbs <archie@freebsd.org>
   39  *
   40  * $FreeBSD$
   41  * $Whistle: ng_bpf.c,v 1.3 1999/12/03 20:30:23 archie Exp $
   42  */
   43 
   44 /*
   45  * BPF NETGRAPH NODE TYPE
   46  *
   47  * This node type accepts any number of hook connections.  With each hook
   48  * is associated a bpf(4) filter program, and two hook names (each possibly
   49  * the empty string).  Incoming packets are compared against the filter;
   50  * matching packets are delivered out the first named hook (or dropped if
   51  * the empty string), and non-matching packets are delivered out the second
   52  * named hook (or dropped if the empty string).
   53  *
   54  * Each hook also keeps statistics about how many packets have matched, etc.
   55  */
   56 
   57 #include "opt_bpf.h"
   58 
   59 #include <sys/param.h>
   60 #include <sys/systm.h>
   61 #include <sys/errno.h>
   62 #include <sys/kernel.h>
   63 #include <sys/malloc.h>
   64 #include <sys/mbuf.h>
   65 
   66 #include <net/bpf.h>
   67 #ifdef BPF_JITTER
   68 #include <net/bpf_jitter.h>
   69 #endif
   70 
   71 #include <netgraph/ng_message.h>
   72 #include <netgraph/netgraph.h>
   73 #include <netgraph/ng_parse.h>
   74 #include <netgraph/ng_bpf.h>
   75 
   76 #ifdef NG_SEPARATE_MALLOC
   77 MALLOC_DEFINE(M_NETGRAPH_BPF, "netgraph_bpf", "netgraph bpf node ");
   78 #else
   79 #define M_NETGRAPH_BPF M_NETGRAPH
   80 #endif
   81 
   82 #define OFFSETOF(s, e) ((char *)&((s *)0)->e - (char *)((s *)0))
   83 
   84 #define ERROUT(x)       do { error = (x); goto done; } while (0)
   85 
   86 /* Per hook private info */
   87 struct ng_bpf_hookinfo {
   88         node_p                  node;
   89         hook_p                  hook;
   90         struct ng_bpf_hookprog  *prog;
   91 #ifdef BPF_JITTER
   92         bpf_jit_filter          *jit_prog;
   93 #endif
   94         struct ng_bpf_hookstat  stats;
   95 };
   96 typedef struct ng_bpf_hookinfo *hinfo_p;
   97 
   98 /* Netgraph methods */
   99 static ng_constructor_t ng_bpf_constructor;
  100 static ng_rcvmsg_t      ng_bpf_rcvmsg;
  101 static ng_shutdown_t    ng_bpf_shutdown;
  102 static ng_newhook_t     ng_bpf_newhook;
  103 static ng_rcvdata_t     ng_bpf_rcvdata;
  104 static ng_disconnect_t  ng_bpf_disconnect;
  105 
  106 /* Internal helper functions */
  107 static int      ng_bpf_setprog(hook_p hook, const struct ng_bpf_hookprog *hp);
  108 
  109 /* Parse type for one struct bfp_insn */
  110 static const struct ng_parse_struct_field ng_bpf_insn_type_fields[] = {
  111         { "code",       &ng_parse_hint16_type   },
  112         { "jt",         &ng_parse_uint8_type    },
  113         { "jf",         &ng_parse_uint8_type    },
  114         { "k",          &ng_parse_uint32_type   },
  115         { NULL }
  116 };
  117 static const struct ng_parse_type ng_bpf_insn_type = {
  118         &ng_parse_struct_type,
  119         &ng_bpf_insn_type_fields
  120 };
  121 
  122 /* Parse type for the field 'bpf_prog' in struct ng_bpf_hookprog */
  123 static int
  124 ng_bpf_hookprogary_getLength(const struct ng_parse_type *type,
  125         const u_char *start, const u_char *buf)
  126 {
  127         const struct ng_bpf_hookprog *hp;
  128 
  129         hp = (const struct ng_bpf_hookprog *)
  130             (buf - OFFSETOF(struct ng_bpf_hookprog, bpf_prog));
  131         return hp->bpf_prog_len;
  132 }
  133 
  134 static const struct ng_parse_array_info ng_bpf_hookprogary_info = {
  135         &ng_bpf_insn_type,
  136         &ng_bpf_hookprogary_getLength,
  137         NULL
  138 };
  139 static const struct ng_parse_type ng_bpf_hookprogary_type = {
  140         &ng_parse_array_type,
  141         &ng_bpf_hookprogary_info
  142 };
  143 
  144 /* Parse type for struct ng_bpf_hookprog */
  145 static const struct ng_parse_struct_field ng_bpf_hookprog_type_fields[]
  146         = NG_BPF_HOOKPROG_TYPE_INFO(&ng_bpf_hookprogary_type);
  147 static const struct ng_parse_type ng_bpf_hookprog_type = {
  148         &ng_parse_struct_type,
  149         &ng_bpf_hookprog_type_fields
  150 };
  151 
  152 /* Parse type for struct ng_bpf_hookstat */
  153 static const struct ng_parse_struct_field ng_bpf_hookstat_type_fields[]
  154         = NG_BPF_HOOKSTAT_TYPE_INFO;
  155 static const struct ng_parse_type ng_bpf_hookstat_type = {
  156         &ng_parse_struct_type,
  157         &ng_bpf_hookstat_type_fields
  158 };
  159 
  160 /* List of commands and how to convert arguments to/from ASCII */
  161 static const struct ng_cmdlist ng_bpf_cmdlist[] = {
  162         {
  163           NGM_BPF_COOKIE,
  164           NGM_BPF_SET_PROGRAM,
  165           "setprogram",
  166           &ng_bpf_hookprog_type,
  167           NULL
  168         },
  169         {
  170           NGM_BPF_COOKIE,
  171           NGM_BPF_GET_PROGRAM,
  172           "getprogram",
  173           &ng_parse_hookbuf_type,
  174           &ng_bpf_hookprog_type
  175         },
  176         {
  177           NGM_BPF_COOKIE,
  178           NGM_BPF_GET_STATS,
  179           "getstats",
  180           &ng_parse_hookbuf_type,
  181           &ng_bpf_hookstat_type
  182         },
  183         {
  184           NGM_BPF_COOKIE,
  185           NGM_BPF_CLR_STATS,
  186           "clrstats",
  187           &ng_parse_hookbuf_type,
  188           NULL
  189         },
  190         {
  191           NGM_BPF_COOKIE,
  192           NGM_BPF_GETCLR_STATS,
  193           "getclrstats",
  194           &ng_parse_hookbuf_type,
  195           &ng_bpf_hookstat_type
  196         },
  197         { 0 }
  198 };
  199 
  200 /* Netgraph type descriptor */
  201 static struct ng_type typestruct = {
  202         .version =      NG_ABI_VERSION,
  203         .name =         NG_BPF_NODE_TYPE,
  204         .constructor =  ng_bpf_constructor,
  205         .rcvmsg =       ng_bpf_rcvmsg,
  206         .shutdown =     ng_bpf_shutdown,
  207         .newhook =      ng_bpf_newhook,
  208         .rcvdata =      ng_bpf_rcvdata,
  209         .disconnect =   ng_bpf_disconnect,
  210         .cmdlist =      ng_bpf_cmdlist,
  211 };
  212 NETGRAPH_INIT(bpf, &typestruct);
  213 
  214 /* Default BPF program for a hook that matches nothing */
  215 static const struct ng_bpf_hookprog ng_bpf_default_prog = {
  216         { '\0' },               /* to be filled in at hook creation time */
  217         { '\0' },
  218         { '\0' },
  219         1,
  220         { BPF_STMT(BPF_RET+BPF_K, 0) }
  221 };
  222 
  223 /*
  224  * Node constructor
  225  *
  226  * We don't keep any per-node private data
  227  * We go via the hooks.
  228  */
  229 static int
  230 ng_bpf_constructor(node_p node)
  231 {
  232         NG_NODE_SET_PRIVATE(node, NULL);
  233         return (0);
  234 }
  235 
  236 /*
  237  * Add a hook
  238  */
  239 static int
  240 ng_bpf_newhook(node_p node, hook_p hook, const char *name)
  241 {
  242         hinfo_p hip;
  243         int error;
  244 
  245         /* Create hook private structure */
  246         MALLOC(hip, hinfo_p, sizeof(*hip), M_NETGRAPH_BPF, M_NOWAIT | M_ZERO);
  247         if (hip == NULL)
  248                 return (ENOMEM);
  249         hip->hook = hook;
  250         NG_HOOK_SET_PRIVATE(hook, hip);
  251         hip->node = node;
  252 
  253         /* Attach the default BPF program */
  254         if ((error = ng_bpf_setprog(hook, &ng_bpf_default_prog)) != 0) {
  255                 FREE(hip, M_NETGRAPH_BPF);
  256                 NG_HOOK_SET_PRIVATE(hook, NULL);
  257                 return (error);
  258         }
  259 
  260         /* Set hook name */
  261         strncpy(hip->prog->thisHook, name, sizeof(hip->prog->thisHook) - 1);
  262         hip->prog->thisHook[sizeof(hip->prog->thisHook) - 1] = '\0';
  263         return (0);
  264 }
  265 
  266 /*
  267  * Receive a control message
  268  */
  269 static int
  270 ng_bpf_rcvmsg(node_p node, item_p item, hook_p lasthook)
  271 {
  272         struct ng_mesg *msg;
  273         struct ng_mesg *resp = NULL;
  274         int error = 0;
  275 
  276         NGI_GET_MSG(item, msg);
  277         switch (msg->header.typecookie) {
  278         case NGM_BPF_COOKIE:
  279                 switch (msg->header.cmd) {
  280                 case NGM_BPF_SET_PROGRAM:
  281                     {
  282                         struct ng_bpf_hookprog *const
  283                             hp = (struct ng_bpf_hookprog *)msg->data;
  284                         hook_p hook;
  285 
  286                         /* Sanity check */
  287                         if (msg->header.arglen < sizeof(*hp)
  288                             || msg->header.arglen
  289                               != NG_BPF_HOOKPROG_SIZE(hp->bpf_prog_len))
  290                                 ERROUT(EINVAL);
  291 
  292                         /* Find hook */
  293                         if ((hook = ng_findhook(node, hp->thisHook)) == NULL)
  294                                 ERROUT(ENOENT);
  295 
  296                         /* Set new program */
  297                         if ((error = ng_bpf_setprog(hook, hp)) != 0)
  298                                 ERROUT(error);
  299                         break;
  300                     }
  301 
  302                 case NGM_BPF_GET_PROGRAM:
  303                     {
  304                         struct ng_bpf_hookprog *hp;
  305                         hook_p hook;
  306 
  307                         /* Sanity check */
  308                         if (msg->header.arglen == 0)
  309                                 ERROUT(EINVAL);
  310                         msg->data[msg->header.arglen - 1] = '\0';
  311 
  312                         /* Find hook */
  313                         if ((hook = ng_findhook(node, msg->data)) == NULL)
  314                                 ERROUT(ENOENT);
  315 
  316                         /* Build response */
  317                         hp = ((hinfo_p)NG_HOOK_PRIVATE(hook))->prog;
  318                         NG_MKRESPONSE(resp, msg,
  319                             NG_BPF_HOOKPROG_SIZE(hp->bpf_prog_len), M_NOWAIT);
  320                         if (resp == NULL)
  321                                 ERROUT(ENOMEM);
  322                         bcopy(hp, resp->data,
  323                            NG_BPF_HOOKPROG_SIZE(hp->bpf_prog_len));
  324                         break;
  325                     }
  326 
  327                 case NGM_BPF_GET_STATS:
  328                 case NGM_BPF_CLR_STATS:
  329                 case NGM_BPF_GETCLR_STATS:
  330                     {
  331                         struct ng_bpf_hookstat *stats;
  332                         hook_p hook;
  333 
  334                         /* Sanity check */
  335                         if (msg->header.arglen == 0)
  336                                 ERROUT(EINVAL);
  337                         msg->data[msg->header.arglen - 1] = '\0';
  338 
  339                         /* Find hook */
  340                         if ((hook = ng_findhook(node, msg->data)) == NULL)
  341                                 ERROUT(ENOENT);
  342                         stats = &((hinfo_p)NG_HOOK_PRIVATE(hook))->stats;
  343 
  344                         /* Build response (if desired) */
  345                         if (msg->header.cmd != NGM_BPF_CLR_STATS) {
  346                                 NG_MKRESPONSE(resp,
  347                                     msg, sizeof(*stats), M_NOWAIT);
  348                                 if (resp == NULL)
  349                                         ERROUT(ENOMEM);
  350                                 bcopy(stats, resp->data, sizeof(*stats));
  351                         }
  352 
  353                         /* Clear stats (if desired) */
  354                         if (msg->header.cmd != NGM_BPF_GET_STATS)
  355                                 bzero(stats, sizeof(*stats));
  356                         break;
  357                     }
  358 
  359                 default:
  360                         error = EINVAL;
  361                         break;
  362                 }
  363                 break;
  364         default:
  365                 error = EINVAL;
  366                 break;
  367         }
  368 done:
  369         NG_RESPOND_MSG(error, node, item, resp);
  370         NG_FREE_MSG(msg);
  371         return (error);
  372 }
  373 
  374 /*
  375  * Receive data on a hook
  376  *
  377  * Apply the filter, and then drop or forward packet as appropriate.
  378  */
  379 static int
  380 ng_bpf_rcvdata(hook_p hook, item_p item)
  381 {
  382         const hinfo_p hip = NG_HOOK_PRIVATE(hook);
  383         int totlen;
  384         int needfree = 0, error = 0;
  385         u_char *data;
  386         hinfo_p dhip;
  387         hook_p dest;
  388         u_int len;
  389         struct mbuf *m;
  390 
  391         m = NGI_M(item);        /* 'item' still owns it.. we are peeking */ 
  392         totlen = m->m_pkthdr.len;
  393         /* Update stats on incoming hook. XXX Can we do 64 bits atomically? */
  394         /* atomic_add_int64(&hip->stats.recvFrames, 1); */
  395         /* atomic_add_int64(&hip->stats.recvOctets, totlen); */
  396         hip->stats.recvFrames++; 
  397         hip->stats.recvOctets += totlen;
  398 
  399         /* Need to put packet in contiguous memory for bpf */
  400         if (m->m_next != NULL) {
  401                 if (totlen > MHLEN) {
  402                         MALLOC(data, u_char *, totlen, M_NETGRAPH_BPF, M_NOWAIT);
  403                         if (data == NULL) {
  404                                 NG_FREE_ITEM(item);
  405                                 return (ENOMEM);
  406                         }
  407                         needfree = 1;
  408                         m_copydata(m, 0, totlen, (caddr_t)data);
  409                 } else {
  410                         NGI_M(item) = m = m_pullup(m, totlen);
  411                         if (m == NULL) {
  412                                 NG_FREE_ITEM(item);
  413                                 return (ENOBUFS);
  414                         }
  415                         data = mtod(m, u_char *);
  416                 }
  417         } else
  418                 data = mtod(m, u_char *);
  419 
  420         /* Run packet through filter */
  421         if (totlen == 0)
  422                 len = 0;        /* don't call bpf_filter() with totlen == 0! */
  423         else {
  424 #ifdef BPF_JITTER
  425                 if (bpf_jitter_enable != 0 && hip->jit_prog != NULL)
  426                         len = (*(hip->jit_prog->func))(data, totlen, totlen);
  427                 else
  428 #endif
  429                 len = bpf_filter(hip->prog->bpf_prog, data, totlen, totlen);
  430         }
  431         if (needfree)
  432                 FREE(data, M_NETGRAPH_BPF);
  433 
  434         /* See if we got a match and find destination hook */
  435         if (len > 0) {
  436 
  437                 /* Update stats */
  438                 /* XXX atomically? */
  439                 hip->stats.recvMatchFrames++;
  440                 hip->stats.recvMatchOctets += totlen;
  441 
  442                 /* Truncate packet length if required by the filter */
  443                 /* Assume this never changes m */
  444                 if (len < totlen) {
  445                         m_adj(m, -(totlen - len));
  446                         totlen -= len;
  447                 }
  448                 dest = ng_findhook(hip->node, hip->prog->ifMatch);
  449         } else
  450                 dest = ng_findhook(hip->node, hip->prog->ifNotMatch);
  451         if (dest == NULL) {
  452                 NG_FREE_ITEM(item);
  453                 return (0);
  454         }
  455 
  456         /* Deliver frame out destination hook */
  457         dhip = NG_HOOK_PRIVATE(dest);
  458         dhip->stats.xmitOctets += totlen;
  459         dhip->stats.xmitFrames++;
  460         NG_FWD_ITEM_HOOK(error, item, dest);
  461         return (error);
  462 }
  463 
  464 /*
  465  * Shutdown processing
  466  */
  467 static int
  468 ng_bpf_shutdown(node_p node)
  469 {
  470         NG_NODE_UNREF(node);
  471         return (0);
  472 }
  473 
  474 /*
  475  * Hook disconnection
  476  */
  477 static int
  478 ng_bpf_disconnect(hook_p hook)
  479 {
  480         const hinfo_p hip = NG_HOOK_PRIVATE(hook);
  481 
  482         KASSERT(hip != NULL, ("%s: null info", __func__));
  483         FREE(hip->prog, M_NETGRAPH_BPF);
  484 #ifdef BPF_JITTER
  485         if (hip->jit_prog != NULL)
  486                 bpf_destroy_jit_filter(hip->jit_prog);
  487 #endif
  488         bzero(hip, sizeof(*hip));
  489         FREE(hip, M_NETGRAPH_BPF);
  490         NG_HOOK_SET_PRIVATE(hook, NULL);                        /* for good measure */
  491         if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
  492         && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook)))) {
  493                 ng_rmnode_self(NG_HOOK_NODE(hook));
  494         }
  495         return (0);
  496 }
  497 
  498 /************************************************************************
  499                         HELPER STUFF
  500  ************************************************************************/
  501 
  502 /*
  503  * Set the BPF program associated with a hook
  504  */
  505 static int
  506 ng_bpf_setprog(hook_p hook, const struct ng_bpf_hookprog *hp0)
  507 {
  508         const hinfo_p hip = NG_HOOK_PRIVATE(hook);
  509         struct ng_bpf_hookprog *hp;
  510 #ifdef BPF_JITTER
  511         bpf_jit_filter *jit_prog;
  512 #endif
  513         int size;
  514 
  515         /* Check program for validity */
  516         if (!bpf_validate(hp0->bpf_prog, hp0->bpf_prog_len))
  517                 return (EINVAL);
  518 
  519         /* Make a copy of the program */
  520         size = NG_BPF_HOOKPROG_SIZE(hp0->bpf_prog_len);
  521         MALLOC(hp, struct ng_bpf_hookprog *, size, M_NETGRAPH_BPF, M_NOWAIT);
  522         if (hp == NULL)
  523                 return (ENOMEM);
  524         bcopy(hp0, hp, size);
  525 #ifdef BPF_JITTER
  526         jit_prog = bpf_jitter(hp->bpf_prog, hp->bpf_prog_len);
  527 #endif
  528 
  529         /* Free previous program, if any, and assign new one */
  530         if (hip->prog != NULL)
  531                 FREE(hip->prog, M_NETGRAPH_BPF);
  532         hip->prog = hp;
  533 #ifdef BPF_JITTER
  534         if (hip->jit_prog != NULL)
  535                 bpf_destroy_jit_filter(hip->jit_prog);
  536         hip->jit_prog = jit_prog;
  537 #endif
  538         return (0);
  539 }
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FreeBSD/Linux Kernel Cross Reference sys/netgraph/ng_bpf.c

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