sys/netgraph/ng_bpf.c

   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, buf[256];
 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 > sizeof(buf)) {
 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                 } else
 409                         data = buf;
 410                 m_copydata(m, 0, totlen, (caddr_t)data);
 411         } else
 412                 data = mtod(m, u_char *);
 413
 414         /* Run packet through filter */
 415         if (totlen == 0)
 416                 len = 0;        /* don't call bpf_filter() with totlen == 0! */
 417         else {
 418 #ifdef BPF_JITTER
 419                 if (bpf_jitter_enable != 0 && hip->jit_prog != NULL)
 420                         len = (*(hip->jit_prog->func))(data, totlen, totlen);
 421                 else
 422 #endif
 423                 len = bpf_filter(hip->prog->bpf_prog, data, totlen, totlen);
 424         }
 425         if (needfree)
 426                 FREE(data, M_NETGRAPH_BPF);
 427
 428         /* See if we got a match and find destination hook */
 429         if (len > 0) {
 430
 431                 /* Update stats */
 432                 /* XXX atomically? */
 433                 hip->stats.recvMatchFrames++;
 434                 hip->stats.recvMatchOctets += totlen;
 435
 436                 /* Truncate packet length if required by the filter */
 437                 /* Assume this never changes m */
 438                 if (len < totlen) {
 439                         m_adj(m, -(totlen - len));
 440                         totlen -= len;
 441                 }
 442                 dest = ng_findhook(hip->node, hip->prog->ifMatch);
 443         } else
 444                 dest = ng_findhook(hip->node, hip->prog->ifNotMatch);
 445         if (dest == NULL) {
 446                 NG_FREE_ITEM(item);
 447                 return (0);
 448         }
 449
 450         /* Deliver frame out destination hook */
 451         dhip = NG_HOOK_PRIVATE(dest);
 452         dhip->stats.xmitOctets += totlen;
 453         dhip->stats.xmitFrames++;
 454         NG_FWD_ITEM_HOOK(error, item, dest);
 455         return (error);
 456 }
 457
 458 /*
 459  * Shutdown processing
 460  */
 461 static int
 462 ng_bpf_shutdown(node_p node)
 463 {
 464         NG_NODE_UNREF(node);
 465         return (0);
 466 }
 467
 468 /*
 469  * Hook disconnection
 470  */
 471 static int
 472 ng_bpf_disconnect(hook_p hook)
 473 {
 474         const hinfo_p hip = NG_HOOK_PRIVATE(hook);
 475
 476         KASSERT(hip != NULL, ("%s: null info", __func__));
 477         FREE(hip->prog, M_NETGRAPH_BPF);
 478 #ifdef BPF_JITTER
 479         if (hip->jit_prog != NULL)
 480                 bpf_destroy_jit_filter(hip->jit_prog);
 481 #endif
 482         bzero(hip, sizeof(*hip));
 483         FREE(hip, M_NETGRAPH_BPF);
 484         NG_HOOK_SET_PRIVATE(hook, NULL);                        /* for good measure */
 485         if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
 486         && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook)))) {
 487                 ng_rmnode_self(NG_HOOK_NODE(hook));
 488         }
 489         return (0);
 490 }
 491
 492 /************************************************************************
 493                         HELPER STUFF
 494  ************************************************************************/
 495
 496 /*
 497  * Set the BPF program associated with a hook
 498  */
 499 static int
 500 ng_bpf_setprog(hook_p hook, const struct ng_bpf_hookprog *hp0)
 501 {
 502         const hinfo_p hip = NG_HOOK_PRIVATE(hook);
 503         struct ng_bpf_hookprog *hp;
 504 #ifdef BPF_JITTER
 505         bpf_jit_filter *jit_prog;
 506 #endif
 507         int size;
 508
 509         /* Check program for validity */
 510         if (!bpf_validate(hp0->bpf_prog, hp0->bpf_prog_len))
 511                 return (EINVAL);
 512
 513         /* Make a copy of the program */
 514         size = NG_BPF_HOOKPROG_SIZE(hp0->bpf_prog_len);
 515         MALLOC(hp, struct ng_bpf_hookprog *, size, M_NETGRAPH_BPF, M_NOWAIT);
 516         if (hp == NULL)
 517                 return (ENOMEM);
 518         bcopy(hp0, hp, size);
 519 #ifdef BPF_JITTER
 520         jit_prog = bpf_jitter(hp->bpf_prog, hp->bpf_prog_len);
 521 #endif
 522
 523         /* Free previous program, if any, and assign new one */
 524         if (hip->prog != NULL)
 525                 FREE(hip->prog, M_NETGRAPH_BPF);
 526         hip->prog = hp;
 527 #ifdef BPF_JITTER
 528         if (hip->jit_prog != NULL)
 529                 bpf_destroy_jit_filter(hip->jit_prog);
 530         hip->jit_prog = jit_prog;
 531 #endif
 532         return (0);
 533 }