/* * ng_bpf.c * * Copyright (c) 1999 Whistle Communications, Inc. * All rights reserved. * * Subject to the following obligations and disclaimer of warranty, use and * redistribution of this software, in source or object code forms, with or * without modifications are expressly permitted by Whistle Communications; * provided, however, that: * 1. Any and all reproductions of the source or object code must include the * copyright notice above and the following disclaimer of warranties; and * 2. No rights are granted, in any manner or form, to use Whistle * Communications, Inc. trademarks, including the mark "WHISTLE * COMMUNICATIONS" on advertising, endorsements, or otherwise except as * such appears in the above copyright notice or in the software. * * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE, * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT. * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANBPF, OR MAKE ANY * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE. * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY * OF SUCH DAMAGE. * * Author: Archie Cobbs * * $FreeBSD$ * $Whistle: ng_bpf.c,v 1.3 1999/12/03 20:30:23 archie Exp $ */ /* * BPF NETGRAPH NODE TYPE * * This node type accepts any number of hook connections. With each hook * is associated a bpf(4) filter program, and two hook names (each possibly * the empty string). Incoming packets are compared against the filter; * matching packets are delivered out the first named hook (or dropped if * the empty string), and non-matching packets are delivered out the second * named hook (or dropped if the empty string). * * Each hook also keeps statistics about how many packets have matched, etc. */ #include #include #include #include #include #include #include #include #include #include #include #define OFFSETOF(s, e) ((char *)&((s *)0)->e - (char *)((s *)0)) #define ERROUT(x) do { error = (x); goto done; } while (0) /* Per hook private info */ struct ng_bpf_hookinfo { node_p node; hook_p hook; struct ng_bpf_hookprog *prog; struct ng_bpf_hookstat stats; }; typedef struct ng_bpf_hookinfo *hinfo_p; /* Netgraph methods */ static ng_constructor_t ng_bpf_constructor; static ng_rcvmsg_t ng_bpf_rcvmsg; static ng_shutdown_t ng_bpf_rmnode; static ng_newhook_t ng_bpf_newhook; static ng_rcvdata_t ng_bpf_rcvdata; static ng_disconnect_t ng_bpf_disconnect; /* Internal helper functions */ static int ng_bpf_setprog(hook_p hook, const struct ng_bpf_hookprog *hp); /* Parse type for one struct bfp_insn */ static const struct ng_parse_struct_info ng_bpf_insn_type_info = { { { "code", &ng_parse_hint16_type }, { "jt", &ng_parse_uint8_type }, { "jf", &ng_parse_uint8_type }, { "k", &ng_parse_uint32_type }, { NULL } } }; static const struct ng_parse_type ng_bpf_insn_type = { &ng_parse_struct_type, &ng_bpf_insn_type_info }; /* Parse type for the field 'bpf_prog' in struct ng_bpf_hookprog */ static int ng_bpf_hookprogary_getLength(const struct ng_parse_type *type, const u_char *start, const u_char *buf) { const struct ng_bpf_hookprog *hp; hp = (const struct ng_bpf_hookprog *) (buf - OFFSETOF(struct ng_bpf_hookprog, bpf_prog)); return hp->bpf_prog_len; } static const struct ng_parse_array_info ng_bpf_hookprogary_info = { &ng_bpf_insn_type, &ng_bpf_hookprogary_getLength, NULL }; static const struct ng_parse_type ng_bpf_hookprogary_type = { &ng_parse_array_type, &ng_bpf_hookprogary_info }; /* Parse type for struct ng_bpf_hookprog */ static const struct ng_parse_struct_info ng_bpf_hookprog_type_info = NG_BPF_HOOKPROG_TYPE_INFO(&ng_bpf_hookprogary_type); static const struct ng_parse_type ng_bpf_hookprog_type = { &ng_parse_struct_type, &ng_bpf_hookprog_type_info }; /* Parse type for struct ng_bpf_hookstat */ static const struct ng_parse_struct_info ng_bpf_hookstat_type_info = NG_BPF_HOOKSTAT_TYPE_INFO; static const struct ng_parse_type ng_bpf_hookstat_type = { &ng_parse_struct_type, &ng_bpf_hookstat_type_info }; /* List of commands and how to convert arguments to/from ASCII */ static const struct ng_cmdlist ng_bpf_cmdlist[] = { { NGM_BPF_COOKIE, NGM_BPF_SET_PROGRAM, "setprogram", &ng_bpf_hookprog_type, NULL }, { NGM_BPF_COOKIE, NGM_BPF_GET_PROGRAM, "getprogram", &ng_parse_hookbuf_type, &ng_bpf_hookprog_type }, { NGM_BPF_COOKIE, NGM_BPF_GET_STATS, "getstats", &ng_parse_hookbuf_type, &ng_bpf_hookstat_type }, { NGM_BPF_COOKIE, NGM_BPF_CLR_STATS, "clrstats", &ng_parse_hookbuf_type, NULL }, { NGM_BPF_COOKIE, NGM_BPF_GETCLR_STATS, "getclrstats", &ng_parse_hookbuf_type, &ng_bpf_hookstat_type }, { 0 } }; /* Netgraph type descriptor */ static struct ng_type typestruct = { NG_VERSION, NG_BPF_NODE_TYPE, NULL, ng_bpf_constructor, ng_bpf_rcvmsg, ng_bpf_rmnode, ng_bpf_newhook, NULL, NULL, ng_bpf_rcvdata, ng_bpf_disconnect, ng_bpf_cmdlist }; NETGRAPH_INIT(bpf, &typestruct); /* Default BPF program for a hook that matches nothing */ static const struct ng_bpf_hookprog ng_bpf_default_prog = { { '\0' }, /* to be filled in at hook creation time */ { '\0' }, { '\0' }, 1, { BPF_STMT(BPF_RET+BPF_K, 0) } }; /* * Node constructor * * We don't keep any per-node private data */ static int ng_bpf_constructor(node_p *nodep) { int error = 0; if ((error = ng_make_node_common(&typestruct, nodep))) return (error); (*nodep)->private = NULL; return (0); } /* * Add a hook */ static int ng_bpf_newhook(node_p node, hook_p hook, const char *name) { hinfo_p hip; int error; /* Create hook private structure */ MALLOC(hip, hinfo_p, sizeof(*hip), M_NETGRAPH, M_NOWAIT | M_ZERO); if (hip == NULL) return (ENOMEM); hip->hook = hook; hook->private = hip; hip->node = node; /* Attach the default BPF program */ if ((error = ng_bpf_setprog(hook, &ng_bpf_default_prog)) != 0) { FREE(hip, M_NETGRAPH); hook->private = NULL; return (error); } /* Set hook name */ strncpy(hip->prog->thisHook, name, sizeof(hip->prog->thisHook) - 1); hip->prog->thisHook[sizeof(hip->prog->thisHook) - 1] = '\0'; return (0); } /* * Receive a control message */ static int ng_bpf_rcvmsg(node_p node, struct ng_mesg *msg, const char *retaddr, struct ng_mesg **rptr, hook_p lasthook) { struct ng_mesg *resp = NULL; int error = 0; switch (msg->header.typecookie) { case NGM_BPF_COOKIE: switch (msg->header.cmd) { case NGM_BPF_SET_PROGRAM: { struct ng_bpf_hookprog *const hp = (struct ng_bpf_hookprog *)msg->data; hook_p hook; /* Sanity check */ if (msg->header.arglen < sizeof(*hp) || msg->header.arglen != NG_BPF_HOOKPROG_SIZE(hp->bpf_prog_len)) ERROUT(EINVAL); /* Find hook */ if ((hook = ng_findhook(node, hp->thisHook)) == NULL) ERROUT(ENOENT); /* Set new program */ if ((error = ng_bpf_setprog(hook, hp)) != 0) ERROUT(error); break; } case NGM_BPF_GET_PROGRAM: { struct ng_bpf_hookprog *hp; hook_p hook; /* Sanity check */ if (msg->header.arglen == 0) ERROUT(EINVAL); msg->data[msg->header.arglen - 1] = '\0'; /* Find hook */ if ((hook = ng_findhook(node, msg->data)) == NULL) ERROUT(ENOENT); /* Build response */ hp = ((hinfo_p)hook->private)->prog; NG_MKRESPONSE(resp, msg, NG_BPF_HOOKPROG_SIZE(hp->bpf_prog_len), M_NOWAIT); if (resp == NULL) ERROUT(ENOMEM); bcopy(hp, resp->data, NG_BPF_HOOKPROG_SIZE(hp->bpf_prog_len)); break; } case NGM_BPF_GET_STATS: case NGM_BPF_CLR_STATS: case NGM_BPF_GETCLR_STATS: { struct ng_bpf_hookstat *stats; hook_p hook; /* Sanity check */ if (msg->header.arglen == 0) ERROUT(EINVAL); msg->data[msg->header.arglen - 1] = '\0'; /* Find hook */ if ((hook = ng_findhook(node, msg->data)) == NULL) ERROUT(ENOENT); stats = &((hinfo_p)hook->private)->stats; /* Build response (if desired) */ if (msg->header.cmd != NGM_BPF_CLR_STATS) { NG_MKRESPONSE(resp, msg, sizeof(*stats), M_NOWAIT); if (resp == NULL) ERROUT(ENOMEM); bcopy(stats, resp->data, sizeof(*stats)); } /* Clear stats (if desired) */ if (msg->header.cmd != NGM_BPF_GET_STATS) bzero(stats, sizeof(*stats)); break; } default: error = EINVAL; break; } break; default: error = EINVAL; break; } if (rptr) *rptr = resp; else if (resp) FREE(resp, M_NETGRAPH); done: FREE(msg, M_NETGRAPH); return (error); } /* * Receive data on a hook * * Apply the filter, and then drop or forward packet as appropriate. */ static int ng_bpf_rcvdata(hook_p hook, struct mbuf *m, meta_p meta, struct mbuf **ret_m, meta_p *ret_meta, struct ng_mesg **resp) { const hinfo_p hip = hook->private; int totlen = m->m_pkthdr.len; int needfree = 0, error = 0; u_char *data, buf[256]; hinfo_p dhip; hook_p dest; u_int len; /* Update stats on incoming hook */ hip->stats.recvFrames++; hip->stats.recvOctets += totlen; /* Need to put packet in contiguous memory for bpf */ if (m->m_next != NULL) { if (totlen > sizeof(buf)) { MALLOC(data, u_char *, totlen, M_NETGRAPH, M_NOWAIT); if (data == NULL) { NG_FREE_DATA(m, meta); return (ENOMEM); } needfree = 1; } else data = buf; m_copydata(m, 0, totlen, (caddr_t)data); } else data = mtod(m, u_char *); /* Run packet through filter */ len = bpf_filter(hip->prog->bpf_prog, data, totlen, totlen); if (needfree) FREE(data, M_NETGRAPH); /* See if we got a match and find destination hook */ if (len > 0) { /* Update stats */ hip->stats.recvMatchFrames++; hip->stats.recvMatchOctets += totlen; /* Truncate packet length if required by the filter */ if (len < totlen) { m_adj(m, -(totlen - len)); totlen -= len; } dest = ng_findhook(hip->node, hip->prog->ifMatch); } else dest = ng_findhook(hip->node, hip->prog->ifNotMatch); if (dest == NULL) { NG_FREE_DATA(m, meta); return (0); } /* Deliver frame out destination hook */ dhip = (hinfo_p)dest->private; dhip->stats.xmitOctets += totlen; dhip->stats.xmitFrames++; NG_SEND_DATA(error, dest, m, meta); return (error); } /* * Shutdown processing */ static int ng_bpf_rmnode(node_p node) { node->flags |= NG_INVALID; ng_cutlinks(node); ng_unname(node); ng_unref(node); return (0); } /* * Hook disconnection */ static int ng_bpf_disconnect(hook_p hook) { const hinfo_p hip = hook->private; KASSERT(hip != NULL, ("%s: null info", __FUNCTION__)); FREE(hip->prog, M_NETGRAPH); bzero(hip, sizeof(*hip)); FREE(hip, M_NETGRAPH); hook->private = NULL; /* for good measure */ if (hook->node->numhooks == 0) ng_rmnode(hook->node); return (0); } /************************************************************************ HELPER STUFF ************************************************************************/ /* * Set the BPF program associated with a hook */ static int ng_bpf_setprog(hook_p hook, const struct ng_bpf_hookprog *hp0) { const hinfo_p hip = hook->private; struct ng_bpf_hookprog *hp; int size; /* Check program for validity */ if (!bpf_validate(hp0->bpf_prog, hp0->bpf_prog_len)) return (EINVAL); /* Make a copy of the program */ size = NG_BPF_HOOKPROG_SIZE(hp0->bpf_prog_len); MALLOC(hp, struct ng_bpf_hookprog *, size, M_NETGRAPH, M_NOWAIT); if (hp == NULL) return (ENOMEM); bcopy(hp0, hp, size); /* Free previous program, if any, and assign new one */ if (hip->prog != NULL) FREE(hip->prog, M_NETGRAPH); hip->prog = hp; return (0); }