/* $OpenBSD: gencode.c,v 1.66 2024/04/08 02:51:14 jsg Exp $ */ /* * Copyright (c) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that: (1) source code distributions * retain the above copyright notice and this paragraph in its entirety, (2) * distributions including binary code include the above copyright notice and * this paragraph in its entirety in the documentation or other materials * provided with the distribution, and (3) all advertising materials mentioning * features or use of this software display the following acknowledgement: * ``This product includes software developed by the University of California, * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of * the University nor the names of its contributors may be used to endorse * or promote products derived from this software without specific prior * written permission. * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "pcap-int.h" #include "ethertype.h" #include "llc.h" #include "gencode.h" #include "ppp.h" #include #ifdef INET6 #include #endif /*INET6*/ #ifdef HAVE_OS_PROTO_H #include "os-proto.h" #endif #define JMP(c) ((c)|BPF_JMP|BPF_K) /* Locals */ static jmp_buf top_ctx; static pcap_t *bpf_pcap; /* Hack for updating VLAN offsets. */ static u_int orig_linktype = -1, orig_nl = -1, orig_nl_nosnap = -1; static u_int mpls_stack = 0; /* XXX */ #ifdef PCAP_FDDIPAD int pcap_fddipad = PCAP_FDDIPAD; #else int pcap_fddipad; #endif __dead void bpf_error(const char *fmt, ...) { va_list ap; va_start(ap, fmt); if (bpf_pcap != NULL) (void)vsnprintf(pcap_geterr(bpf_pcap), PCAP_ERRBUF_SIZE, fmt, ap); va_end(ap); longjmp(top_ctx, 1); /* NOTREACHED */ } static void init_linktype(int); static int alloc_reg(void); static void free_reg(int); static struct block *root; /* initialization code used for variable link header */ static struct slist *init_code = NULL; /* Flags and registers for variable link type handling */ static int variable_nl; static int nl_reg, iphl_reg; /* * Track memory allocations, for bulk freeing at the end */ #define NMEMBAG 16 #define MEMBAG0SIZE (4096 / sizeof (void *)) struct membag { u_int total; u_int slot; void **ptrs; /* allocated array[total] to each malloc */ }; static struct membag membag[NMEMBAG]; static int cur_membag; static void *newchunk(size_t); static void freechunks(void); static __inline struct block *new_block(int); static __inline struct slist *new_stmt(int); static struct block *gen_retblk(int); static __inline void syntax(void); static void backpatch(struct block *, struct block *); static void merge(struct block *, struct block *); static struct block *gen_cmp(u_int, u_int, bpf_int32); static struct block *gen_cmp_gt(u_int, u_int, bpf_int32); static struct block *gen_cmp_nl(u_int, u_int, bpf_int32); static struct block *gen_mcmp(u_int, u_int, bpf_int32, bpf_u_int32); static struct block *gen_mcmp_nl(u_int, u_int, bpf_int32, bpf_u_int32); static struct block *gen_bcmp(u_int, u_int, const u_char *); static struct block *gen_uncond(int); static __inline struct block *gen_true(void); static __inline struct block *gen_false(void); static struct block *gen_linktype(int); static struct block *gen_hostop(bpf_u_int32, bpf_u_int32, int, int, u_int, u_int); #ifdef INET6 static struct block *gen_hostop6(struct in6_addr *, struct in6_addr *, int, int, u_int, u_int); #endif static struct block *gen_ehostop(const u_char *, int); static struct block *gen_fhostop(const u_char *, int); static struct block *gen_dnhostop(bpf_u_int32, int, u_int); static struct block *gen_p80211_hostop(const u_char *, int); static struct block *gen_p80211_addr(int, u_int, const u_char *); static struct block *gen_host(bpf_u_int32, bpf_u_int32, int, int); #ifdef INET6 static struct block *gen_host6(struct in6_addr *, struct in6_addr *, int, int); #endif #ifndef INET6 static struct block *gen_gateway(const u_char *, bpf_u_int32 **, int, int); #endif static struct block *gen_ipfrag(void); static struct block *gen_portatom(int, bpf_int32); #ifdef INET6 static struct block *gen_portatom6(int, bpf_int32); #endif struct block *gen_portop(int, int, int); static struct block *gen_port(int, int, int); #ifdef INET6 struct block *gen_portop6(int, int, int); static struct block *gen_port6(int, int, int); #endif static int lookup_proto(const char *, int); static struct block *gen_protochain(int, int, int); static struct block *gen_proto(int, int, int); static struct slist *xfer_to_x(struct arth *); static struct slist *xfer_to_a(struct arth *); static struct block *gen_len(int, int); static void * newchunk(size_t n) { struct membag *m; int k, size; void *p; m = &membag[cur_membag]; if (m->total != 0 && m->total - m->slot == 0) { if (++cur_membag == NMEMBAG) bpf_error("out of memory"); m = &membag[cur_membag]; } if (m->total - m->slot == 0) { m->ptrs = calloc(sizeof (char *), MEMBAG0SIZE << cur_membag); if (m->ptrs == NULL) bpf_error("out of memory"); m->total = MEMBAG0SIZE << cur_membag; m->slot = 0; } p = calloc(1, n); if (p == NULL) bpf_error("out of memory"); m->ptrs[m->slot++] = p; return (p); } static void freechunks(void) { int i, j; for (i = 0; i <= cur_membag; i++) { if (membag[i].ptrs == NULL) continue; for (j = 0; j < membag[i].slot; j++) free(membag[i].ptrs[j]); free(membag[i].ptrs); membag[i].ptrs = NULL; membag[i].slot = membag[i].total = 0; } cur_membag = 0; } /* * A strdup whose allocations are freed after code generation is over. */ char * sdup(const char *s) { int n = strlen(s) + 1; char *cp = newchunk(n); strlcpy(cp, s, n); return (cp); } static __inline struct block * new_block(int code) { struct block *p; p = (struct block *)newchunk(sizeof(*p)); p->s.code = code; p->head = p; return p; } static __inline struct slist * new_stmt(int code) { struct slist *p; p = (struct slist *)newchunk(sizeof(*p)); p->s.code = code; return p; } static struct block * gen_retblk(int v) { struct block *b = new_block(BPF_RET|BPF_K); b->s.k = v; return b; } static __inline void syntax(void) { bpf_error("syntax error in filter expression"); } static bpf_u_int32 netmask; static int snaplen; int no_optimize; int pcap_compile(pcap_t *p, struct bpf_program *program, const char *buf, int optimize, bpf_u_int32 mask) { extern int n_errors; int len; no_optimize = 0; n_errors = 0; root = NULL; bpf_pcap = p; if (setjmp(top_ctx)) { freechunks(); return (-1); } netmask = mask; snaplen = pcap_snapshot(p); lex_init(buf ? buf : ""); init_linktype(pcap_datalink(p)); (void)pcap_parse(); if (n_errors) syntax(); if (root == NULL) root = gen_retblk(snaplen); if (optimize && !no_optimize) { bpf_optimize(&root); if (root == NULL || (root->s.code == (BPF_RET|BPF_K) && root->s.k == 0)) bpf_error("expression rejects all packets"); } program->bf_insns = icode_to_fcode(root, &len); program->bf_len = len; freechunks(); return (0); } /* * entry point for using the compiler with no pcap open * pass in all the stuff that is needed explicitly instead. */ int pcap_compile_nopcap(int snaplen_arg, int linktype_arg, struct bpf_program *program, const char *buf, int optimize, bpf_u_int32 mask) { extern int n_errors; int len; n_errors = 0; root = NULL; bpf_pcap = NULL; if (setjmp(top_ctx)) { freechunks(); return (-1); } netmask = mask; /* XXX needed? I don't grok the use of globals here. */ snaplen = snaplen_arg; lex_init(buf ? buf : ""); init_linktype(linktype_arg); (void)pcap_parse(); if (n_errors) syntax(); if (root == NULL) root = gen_retblk(snaplen_arg); if (optimize) { bpf_optimize(&root); if (root == NULL || (root->s.code == (BPF_RET|BPF_K) && root->s.k == 0)) bpf_error("expression rejects all packets"); } program->bf_insns = icode_to_fcode(root, &len); program->bf_len = len; freechunks(); return (0); } /* * Clean up a "struct bpf_program" by freeing all the memory allocated * in it. */ void pcap_freecode(struct bpf_program *program) { program->bf_len = 0; if (program->bf_insns != NULL) { free((char *)program->bf_insns); program->bf_insns = NULL; } } /* * Backpatch the blocks in 'list' to 'target'. The 'sense' field indicates * which of the jt and jf fields has been resolved and which is a pointer * back to another unresolved block (or nil). At least one of the fields * in each block is already resolved. */ static void backpatch(struct block *list, struct block *target) { struct block *next; while (list) { if (!list->sense) { next = JT(list); JT(list) = target; } else { next = JF(list); JF(list) = target; } list = next; } } /* * Merge the lists in b0 and b1, using the 'sense' field to indicate * which of jt and jf is the link. */ static void merge(struct block *b0, struct block *b1) { struct block **p = &b0; /* Find end of list. */ while (*p) p = !((*p)->sense) ? &JT(*p) : &JF(*p); /* Concatenate the lists. */ *p = b1; } void finish_parse(struct block *p) { backpatch(p, gen_retblk(snaplen)); p->sense = !p->sense; backpatch(p, gen_retblk(0)); root = p->head; /* prepend initialization code to root */ if (init_code != NULL && root != NULL) { sappend(init_code, root->stmts); root->stmts = init_code; init_code = NULL; } if (iphl_reg != -1) { free_reg(iphl_reg); iphl_reg = -1; } if (nl_reg != -1) { free_reg(nl_reg); nl_reg = -1; } } void gen_and(struct block *b0, struct block *b1) { backpatch(b0, b1->head); b0->sense = !b0->sense; b1->sense = !b1->sense; merge(b1, b0); b1->sense = !b1->sense; b1->head = b0->head; } void gen_or(struct block *b0, struct block *b1) { b0->sense = !b0->sense; backpatch(b0, b1->head); b0->sense = !b0->sense; merge(b1, b0); b1->head = b0->head; } void gen_not(struct block *b) { b->sense = !b->sense; } static struct block * gen_cmp(u_int offset, u_int size, bpf_int32 v) { struct slist *s; struct block *b; s = new_stmt(BPF_LD|BPF_ABS|size); s->s.k = offset; b = new_block(JMP(BPF_JEQ)); b->stmts = s; b->s.k = v; return b; } static struct block * gen_cmp_gt(u_int offset, u_int size, bpf_int32 v) { struct slist *s; struct block *b; s = new_stmt(BPF_LD|BPF_ABS|size); s->s.k = offset; b = new_block(JMP(BPF_JGT)); b->stmts = s; b->s.k = v; return b; } static struct block * gen_mcmp(u_int offset, u_int size, bpf_int32 v, bpf_u_int32 mask) { struct block *b = gen_cmp(offset, size, v); struct slist *s; if (mask != 0xffffffff) { s = new_stmt(BPF_ALU|BPF_AND|BPF_K); s->s.k = mask; sappend(b->stmts, s); } return b; } /* Like gen_mcmp with 'dynamic off_nl' added to the offset */ static struct block * gen_mcmp_nl(u_int offset, u_int size, bpf_int32 v, bpf_u_int32 mask) { struct block *b = gen_cmp_nl(offset, size, v); struct slist *s; if (mask != 0xffffffff) { s = new_stmt(BPF_ALU|BPF_AND|BPF_K); s->s.k = mask; sappend(b->stmts, s); } return b; } static struct block * gen_bcmp(u_int offset, u_int size, const u_char *v) { struct block *b, *tmp; b = NULL; while (size >= 4) { const u_char *p = &v[size - 4]; bpf_int32 w = ((bpf_int32)p[0] << 24) | ((bpf_int32)p[1] << 16) | ((bpf_int32)p[2] << 8) | p[3]; tmp = gen_cmp(offset + size - 4, BPF_W, w); if (b != NULL) gen_and(b, tmp); b = tmp; size -= 4; } while (size >= 2) { const u_char *p = &v[size - 2]; bpf_int32 w = ((bpf_int32)p[0] << 8) | p[1]; tmp = gen_cmp(offset + size - 2, BPF_H, w); if (b != NULL) gen_and(b, tmp); b = tmp; size -= 2; } if (size > 0) { tmp = gen_cmp(offset, BPF_B, (bpf_int32)v[0]); if (b != NULL) gen_and(b, tmp); b = tmp; } return b; } /* * Various code constructs need to know the layout of the data link * layer. These variables give the necessary offsets. off_linktype * is set to -1 for no encapsulation, in which case, IP is assumed. */ static u_int off_linktype; static u_int off_nl; static u_int off_nl_nosnap; static int linktype; /* Generate code to load the dynamic 'off_nl' to the X register */ static struct slist * nl2X_stmt(void) { struct slist *s, *tmp; if (nl_reg == -1) { switch (linktype) { case DLT_PFLOG: /* The pflog header contains PFLOG_REAL_HDRLEN which does NOT include the padding. Round up to the nearest dword boundary */ s = new_stmt(BPF_LD|BPF_B|BPF_ABS); s->s.k = 0; tmp = new_stmt(BPF_ALU|BPF_ADD|BPF_K); tmp->s.k = 3; sappend(s, tmp); tmp = new_stmt(BPF_ALU|BPF_AND|BPF_K); tmp->s.k = 0xfc; sappend(s, tmp); nl_reg = alloc_reg(); tmp = new_stmt(BPF_ST); tmp->s.k = nl_reg; sappend(s, tmp); break; default: bpf_error("Unknown header size for link type 0x%x", linktype); } if (init_code == NULL) init_code = s; else sappend(init_code, s); } s = new_stmt(BPF_LDX|BPF_MEM); s->s.k = nl_reg; return s; } /* Like gen_cmp but adds the dynamic 'off_nl' to the offset */ static struct block * gen_cmp_nl(u_int offset, u_int size, bpf_int32 v) { struct slist *s, *tmp; struct block *b; if (variable_nl) { s = nl2X_stmt(); tmp = new_stmt(BPF_LD|BPF_IND|size); tmp->s.k = offset; sappend(s, tmp); } else { s = new_stmt(BPF_LD|BPF_ABS|size); s->s.k = offset + off_nl; } b = new_block(JMP(BPF_JEQ)); b->stmts = s; b->s.k = v; return b; } static void init_linktype(int type) { linktype = type; init_code = NULL; nl_reg = iphl_reg = -1; switch (type) { case DLT_EN10MB: off_linktype = 12; off_nl = 14; return; case DLT_SLIP: /* * SLIP doesn't have a link level type. The 16 byte * header is hacked into our SLIP driver. */ off_linktype = -1; off_nl = 16; return; case DLT_SLIP_BSDOS: /* XXX this may be the same as the DLT_PPP_BSDOS case */ off_linktype = -1; /* XXX end */ off_nl = 24; return; case DLT_NULL: off_linktype = 0; off_nl = 4; return; case DLT_PPP: off_linktype = 2; off_nl = 4; return; case DLT_PPP_SERIAL: off_linktype = -1; off_nl = 2; return; case DLT_PPP_ETHER: /* * This does not include the Ethernet header, and * only covers session state. */ off_linktype = 6; off_nl = 8; return; case DLT_PPP_BSDOS: off_linktype = 5; off_nl = 24; return; case DLT_FDDI: /* * FDDI doesn't really have a link-level type field. * We assume that SSAP = SNAP is being used and pick * out the encapsulated Ethernet type. */ off_linktype = 19; #ifdef PCAP_FDDIPAD off_linktype += pcap_fddipad; #endif off_nl = 21; #ifdef PCAP_FDDIPAD off_nl += pcap_fddipad; #endif return; case DLT_IEEE802: off_linktype = 20; off_nl = 22; return; case DLT_IEEE802_11: off_linktype = 30; /* XXX variable */ off_nl = 32; return; case DLT_IEEE802_11_RADIO: /* XXX variable */ off_linktype = 30 + IEEE80211_RADIOTAP_HDRLEN; off_nl = 32 + IEEE80211_RADIOTAP_HDRLEN; return; case DLT_ATM_RFC1483: /* * assume routed, non-ISO PDUs * (i.e., LLC = 0xAA-AA-03, OUT = 0x00-00-00) */ off_linktype = 6; off_nl = 8; return; case DLT_LOOP: off_linktype = 0; off_nl = 4; return; case DLT_ENC: off_linktype = -1; off_nl = 12; return; case DLT_PFLOG: off_linktype = 0; variable_nl = 1; off_nl = 0; return; case DLT_PFSYNC: off_linktype = -1; off_nl = 4; return; case DLT_OPENFLOW: off_linktype = -1; off_nl = 12; return; case DLT_USBPCAP: /* FALLTHROUGH */ case DLT_RAW: off_linktype = -1; off_nl = 0; return; } bpf_error("unknown data link type 0x%x", linktype); /* NOTREACHED */ } static struct block * gen_uncond(int rsense) { struct block *b; struct slist *s; s = new_stmt(BPF_LD|BPF_IMM); s->s.k = !rsense; b = new_block(JMP(BPF_JEQ)); b->stmts = s; return b; } static __inline struct block * gen_true(void) { return gen_uncond(1); } static __inline struct block * gen_false(void) { return gen_uncond(0); } static struct block * gen_linktype(int proto) { struct block *b0, *b1; /* If we're not using encapsulation and checking for IP, we're done */ if ((off_linktype == -1 || mpls_stack > 0) && proto == ETHERTYPE_IP) return gen_true(); #ifdef INET6 /* this isn't the right thing to do, but sometimes necessary */ if ((off_linktype == -1 || mpls_stack > 0) && proto == ETHERTYPE_IPV6) return gen_true(); #endif switch (linktype) { case DLT_EN10MB: if (proto <= ETHERMTU) { /* This is an LLC SAP value */ b0 = gen_cmp_gt(off_linktype, BPF_H, ETHERMTU); gen_not(b0); b1 = gen_cmp(off_linktype + 2, BPF_B, (bpf_int32)proto); gen_and(b0, b1); return b1; } else { /* This is an Ethernet type */ return gen_cmp(off_linktype, BPF_H, (bpf_int32)proto); } break; case DLT_SLIP: return gen_false(); case DLT_PPP: case DLT_PPP_ETHER: if (proto == ETHERTYPE_IP) proto = PPP_IP; /* XXX was 0x21 */ #ifdef INET6 else if (proto == ETHERTYPE_IPV6) proto = PPP_IPV6; #endif break; case DLT_PPP_BSDOS: switch (proto) { case ETHERTYPE_IP: b0 = gen_cmp(off_linktype, BPF_H, PPP_IP); b1 = gen_cmp(off_linktype, BPF_H, PPP_VJC); gen_or(b0, b1); b0 = gen_cmp(off_linktype, BPF_H, PPP_VJNC); gen_or(b1, b0); return b0; #ifdef INET6 case ETHERTYPE_IPV6: proto = PPP_IPV6; /* more to go? */ break; #endif /* INET6 */ case ETHERTYPE_DN: proto = PPP_DECNET; break; case ETHERTYPE_ATALK: proto = PPP_APPLE; break; case ETHERTYPE_NS: proto = PPP_NS; break; } break; case DLT_LOOP: case DLT_ENC: case DLT_NULL: { int v; if (proto == ETHERTYPE_IP) v = AF_INET; #ifdef INET6 else if (proto == ETHERTYPE_IPV6) v = AF_INET6; #endif /* INET6 */ else return gen_false(); /* * For DLT_NULL, the link-layer header is a 32-bit word * containing an AF_ value in *host* byte order, and for * DLT_ENC, the link-layer header begins with a 32-bit * word containing an AF_ value in host byte order. * * For DLT_LOOP, the link-layer header is a 32-bit * word containing an AF_ value in *network* byte order. */ if (linktype != DLT_LOOP) v = htonl(v); return (gen_cmp(0, BPF_W, (bpf_int32)v)); break; } case DLT_PFLOG: if (proto == ETHERTYPE_IP) return (gen_cmp(offsetof(struct pfloghdr, af), BPF_B, (bpf_int32)AF_INET)); #ifdef INET6 else if (proto == ETHERTYPE_IPV6) return (gen_cmp(offsetof(struct pfloghdr, af), BPF_B, (bpf_int32)AF_INET6)); #endif /* INET6 */ else return gen_false(); break; } return gen_cmp(off_linktype, BPF_H, (bpf_int32)proto); } static struct block * gen_hostop(bpf_u_int32 addr, bpf_u_int32 mask, int dir, int proto, u_int src_off, u_int dst_off) { struct block *b0, *b1; u_int offset; switch (dir) { case Q_SRC: offset = src_off; break; case Q_DST: offset = dst_off; break; case Q_AND: b0 = gen_hostop(addr, mask, Q_SRC, proto, src_off, dst_off); b1 = gen_hostop(addr, mask, Q_DST, proto, src_off, dst_off); gen_and(b0, b1); return b1; case Q_OR: case Q_DEFAULT: b0 = gen_hostop(addr, mask, Q_SRC, proto, src_off, dst_off); b1 = gen_hostop(addr, mask, Q_DST, proto, src_off, dst_off); gen_or(b0, b1); return b1; default: bpf_error("direction not supported on linktype 0x%x", linktype); } b0 = gen_linktype(proto); b1 = gen_mcmp_nl(offset, BPF_W, (bpf_int32)addr, mask); gen_and(b0, b1); return b1; } #ifdef INET6 static struct block * gen_hostop6(struct in6_addr *addr, struct in6_addr *mask, int dir, int proto, u_int src_off, u_int dst_off) { struct block *b0, *b1; u_int offset; u_int32_t *a, *m; switch (dir) { case Q_SRC: offset = src_off; break; case Q_DST: offset = dst_off; break; case Q_AND: b0 = gen_hostop6(addr, mask, Q_SRC, proto, src_off, dst_off); b1 = gen_hostop6(addr, mask, Q_DST, proto, src_off, dst_off); gen_and(b0, b1); return b1; case Q_OR: case Q_DEFAULT: b0 = gen_hostop6(addr, mask, Q_SRC, proto, src_off, dst_off); b1 = gen_hostop6(addr, mask, Q_DST, proto, src_off, dst_off); gen_or(b0, b1); return b1; default: bpf_error("direction not supported on linktype 0x%x", linktype); } /* this order is important */ a = (u_int32_t *)addr; m = (u_int32_t *)mask; b1 = gen_mcmp_nl(offset + 12, BPF_W, ntohl(a[3]), ntohl(m[3])); b0 = gen_mcmp_nl(offset + 8, BPF_W, ntohl(a[2]), ntohl(m[2])); gen_and(b0, b1); b0 = gen_mcmp_nl(offset + 4, BPF_W, ntohl(a[1]), ntohl(m[1])); gen_and(b0, b1); b0 = gen_mcmp_nl(offset + 0, BPF_W, ntohl(a[0]), ntohl(m[0])); gen_and(b0, b1); b0 = gen_linktype(proto); gen_and(b0, b1); return b1; } #endif /*INET6*/ static struct block * gen_ehostop(const u_char *eaddr, int dir) { struct block *b0, *b1; switch (dir) { case Q_SRC: return gen_bcmp(6, 6, eaddr); case Q_DST: return gen_bcmp(0, 6, eaddr); case Q_AND: b0 = gen_ehostop(eaddr, Q_SRC); b1 = gen_ehostop(eaddr, Q_DST); gen_and(b0, b1); return b1; case Q_DEFAULT: case Q_OR: b0 = gen_ehostop(eaddr, Q_SRC); b1 = gen_ehostop(eaddr, Q_DST); gen_or(b0, b1); return b1; default: bpf_error("direction not supported on linktype 0x%x", linktype); } /* NOTREACHED */ } /* * Like gen_ehostop, but for DLT_FDDI */ static struct block * gen_fhostop(const u_char *eaddr, int dir) { struct block *b0, *b1; switch (dir) { case Q_SRC: #ifdef PCAP_FDDIPAD return gen_bcmp(6 + 1 + pcap_fddipad, 6, eaddr); #else return gen_bcmp(6 + 1, 6, eaddr); #endif case Q_DST: #ifdef PCAP_FDDIPAD return gen_bcmp(0 + 1 + pcap_fddipad, 6, eaddr); #else return gen_bcmp(0 + 1, 6, eaddr); #endif case Q_AND: b0 = gen_fhostop(eaddr, Q_SRC); b1 = gen_fhostop(eaddr, Q_DST); gen_and(b0, b1); return b1; case Q_DEFAULT: case Q_OR: b0 = gen_fhostop(eaddr, Q_SRC); b1 = gen_fhostop(eaddr, Q_DST); gen_or(b0, b1); return b1; default: bpf_error("direction not supported on linktype 0x%x", linktype); } /* NOTREACHED */ } /* * This is quite tricky because there may be pad bytes in front of the * DECNET header, and then there are two possible data packet formats that * carry both src and dst addresses, plus 5 packet types in a format that * carries only the src node, plus 2 types that use a different format and * also carry just the src node. * * Yuck. * * Instead of doing those all right, we just look for data packets with * 0 or 1 bytes of padding. If you want to look at other packets, that * will require a lot more hacking. * * To add support for filtering on DECNET "areas" (network numbers) * one would want to add a "mask" argument to this routine. That would * make the filter even more inefficient, although one could be clever * and not generate masking instructions if the mask is 0xFFFF. */ static struct block * gen_dnhostop(bpf_u_int32 addr, int dir, u_int base_off) { struct block *b0, *b1, *b2, *tmp; u_int offset_lh; /* offset if long header is received */ u_int offset_sh; /* offset if short header is received */ switch (dir) { case Q_DST: offset_sh = 1; /* follows flags */ offset_lh = 7; /* flgs,darea,dsubarea,HIORD */ break; case Q_SRC: offset_sh = 3; /* follows flags, dstnode */ offset_lh = 15; /* flgs,darea,dsubarea,did,sarea,ssub,HIORD */ break; case Q_AND: /* Inefficient because we do our Calvinball dance twice */ b0 = gen_dnhostop(addr, Q_SRC, base_off); b1 = gen_dnhostop(addr, Q_DST, base_off); gen_and(b0, b1); return b1; case Q_OR: case Q_DEFAULT: /* Inefficient because we do our Calvinball dance twice */ b0 = gen_dnhostop(addr, Q_SRC, base_off); b1 = gen_dnhostop(addr, Q_DST, base_off); gen_or(b0, b1); return b1; default: bpf_error("direction not supported on linktype 0x%x", linktype); } b0 = gen_linktype(ETHERTYPE_DN); /* Check for pad = 1, long header case */ tmp = gen_mcmp_nl(base_off + 2, BPF_H, (bpf_int32)ntohs(0x0681), (bpf_int32)ntohs(0x07FF)); b1 = gen_cmp_nl(base_off + 2 + 1 + offset_lh, BPF_H, (bpf_int32)ntohs(addr)); gen_and(tmp, b1); /* Check for pad = 0, long header case */ tmp = gen_mcmp_nl(base_off + 2, BPF_B, (bpf_int32)0x06, (bpf_int32)0x7); b2 = gen_cmp_nl(base_off + 2 + offset_lh, BPF_H, (bpf_int32)ntohs(addr)); gen_and(tmp, b2); gen_or(b2, b1); /* Check for pad = 1, short header case */ tmp = gen_mcmp_nl(base_off + 2, BPF_H, (bpf_int32)ntohs(0x0281), (bpf_int32)ntohs(0x07FF)); b2 = gen_cmp_nl(base_off + 2 + 1 + offset_sh, BPF_H, (bpf_int32)ntohs(addr)); gen_and(tmp, b2); gen_or(b2, b1); /* Check for pad = 0, short header case */ tmp = gen_mcmp_nl(base_off + 2, BPF_B, (bpf_int32)0x02, (bpf_int32)0x7); b2 = gen_cmp_nl(base_off + 2 + offset_sh, BPF_H, (bpf_int32)ntohs(addr)); gen_and(tmp, b2); gen_or(b2, b1); /* Combine with test for linktype */ gen_and(b0, b1); return b1; } static struct block * gen_host(bpf_u_int32 addr, bpf_u_int32 mask, int proto, int dir) { struct block *b0, *b1; switch (proto) { case Q_DEFAULT: b0 = gen_host(addr, mask, Q_IP, dir); b1 = gen_host(addr, mask, Q_ARP, dir); gen_or(b0, b1); b0 = gen_host(addr, mask, Q_RARP, dir); gen_or(b1, b0); return b0; case Q_IP: return gen_hostop(addr, mask, dir, ETHERTYPE_IP, 12, 16); case Q_RARP: return gen_hostop(addr, mask, dir, ETHERTYPE_REVARP, 14, 24); case Q_ARP: return gen_hostop(addr, mask, dir, ETHERTYPE_ARP, 14, 24); case Q_TCP: bpf_error("'tcp' modifier applied to host"); case Q_UDP: bpf_error("'udp' modifier applied to host"); case Q_ICMP: bpf_error("'icmp' modifier applied to host"); case Q_IGMP: bpf_error("'igmp' modifier applied to host"); case Q_IGRP: bpf_error("'igrp' modifier applied to host"); case Q_PIM: bpf_error("'pim' modifier applied to host"); case Q_STP: bpf_error("'stp' modifier applied to host"); case Q_ATALK: bpf_error("ATALK host filtering not implemented"); case Q_DECNET: return gen_dnhostop(addr, dir, 0); case Q_SCA: bpf_error("SCA host filtering not implemented"); case Q_LAT: bpf_error("LAT host filtering not implemented"); case Q_MOPDL: bpf_error("MOPDL host filtering not implemented"); case Q_MOPRC: bpf_error("MOPRC host filtering not implemented"); #ifdef INET6 case Q_IPV6: bpf_error("'ip6' modifier applied to ip host"); case Q_ICMPV6: bpf_error("'icmp6' modifier applied to host"); #endif /* INET6 */ case Q_AH: bpf_error("'ah' modifier applied to host"); case Q_ESP: bpf_error("'esp' modifier applied to host"); default: bpf_error("direction not supported on linktype 0x%x", linktype); } /* NOTREACHED */ } #ifdef INET6 static struct block * gen_host6(struct in6_addr *addr, struct in6_addr *mask, int proto, int dir) { switch (proto) { case Q_DEFAULT: return gen_host6(addr, mask, Q_IPV6, dir); case Q_IP: bpf_error("'ip' modifier applied to ip6 host"); case Q_RARP: bpf_error("'rarp' modifier applied to ip6 host"); case Q_ARP: bpf_error("'arp' modifier applied to ip6 host"); case Q_TCP: bpf_error("'tcp' modifier applied to host"); case Q_UDP: bpf_error("'udp' modifier applied to host"); case Q_ICMP: bpf_error("'icmp' modifier applied to host"); case Q_IGMP: bpf_error("'igmp' modifier applied to host"); case Q_IGRP: bpf_error("'igrp' modifier applied to host"); case Q_PIM: bpf_error("'pim' modifier applied to host"); case Q_STP: bpf_error("'stp' modifier applied to host"); case Q_ATALK: bpf_error("ATALK host filtering not implemented"); case Q_DECNET: bpf_error("'decnet' modifier applied to ip6 host"); case Q_SCA: bpf_error("SCA host filtering not implemented"); case Q_LAT: bpf_error("LAT host filtering not implemented"); case Q_MOPDL: bpf_error("MOPDL host filtering not implemented"); case Q_MOPRC: bpf_error("MOPRC host filtering not implemented"); case Q_IPV6: return gen_hostop6(addr, mask, dir, ETHERTYPE_IPV6, 8, 24); case Q_ICMPV6: bpf_error("'icmp6' modifier applied to host"); case Q_AH: bpf_error("'ah' modifier applied to host"); case Q_ESP: bpf_error("'esp' modifier applied to host"); default: abort(); } /* NOTREACHED */ } #endif /*INET6*/ #ifndef INET6 static struct block * gen_gateway(const u_char *eaddr, bpf_u_int32 **alist, int proto, int dir) { struct block *b0, *b1, *tmp; if (dir != 0) bpf_error("direction applied to 'gateway'"); switch (proto) { case Q_DEFAULT: case Q_IP: case Q_ARP: case Q_RARP: if (linktype == DLT_EN10MB) b0 = gen_ehostop(eaddr, Q_OR); else if (linktype == DLT_FDDI) b0 = gen_fhostop(eaddr, Q_OR); else bpf_error( "'gateway' supported only on ethernet or FDDI"); b1 = gen_host(**alist++, 0xffffffff, proto, Q_OR); while (*alist) { tmp = gen_host(**alist++, 0xffffffff, proto, Q_OR); gen_or(b1, tmp); b1 = tmp; } gen_not(b1); gen_and(b0, b1); return b1; } bpf_error("illegal modifier of 'gateway'"); /* NOTREACHED */ } #endif /*INET6*/ struct block * gen_proto_abbrev(int proto) { struct block *b0 = NULL, *b1; switch (proto) { case Q_TCP: b1 = gen_proto(IPPROTO_TCP, Q_IP, Q_DEFAULT); #ifdef INET6 b0 = gen_proto(IPPROTO_TCP, Q_IPV6, Q_DEFAULT); gen_or(b0, b1); #endif break; case Q_UDP: b1 = gen_proto(IPPROTO_UDP, Q_IP, Q_DEFAULT); #ifdef INET6 b0 = gen_proto(IPPROTO_UDP, Q_IPV6, Q_DEFAULT); gen_or(b0, b1); #endif break; case Q_ICMP: b1 = gen_proto(IPPROTO_ICMP, Q_IP, Q_DEFAULT); break; #ifndef IPPROTO_IGMP #define IPPROTO_IGMP 2 #endif case Q_IGMP: b1 = gen_proto(IPPROTO_IGMP, Q_IP, Q_DEFAULT); break; #ifndef IPPROTO_IGRP #define IPPROTO_IGRP 9 #endif case Q_IGRP: b1 = gen_proto(IPPROTO_IGRP, Q_IP, Q_DEFAULT); break; #ifndef IPPROTO_PIM #define IPPROTO_PIM 103 #endif case Q_PIM: b1 = gen_proto(IPPROTO_PIM, Q_IP, Q_DEFAULT); #ifdef INET6 b0 = gen_proto(IPPROTO_PIM, Q_IPV6, Q_DEFAULT); gen_or(b0, b1); #endif break; case Q_IP: b1 = gen_linktype(ETHERTYPE_IP); break; case Q_ARP: b1 = gen_linktype(ETHERTYPE_ARP); break; case Q_RARP: b1 = gen_linktype(ETHERTYPE_REVARP); break; case Q_LINK: bpf_error("link layer applied in wrong context"); case Q_ATALK: b1 = gen_linktype(ETHERTYPE_ATALK); break; case Q_DECNET: b1 = gen_linktype(ETHERTYPE_DN); break; case Q_SCA: b1 = gen_linktype(ETHERTYPE_SCA); break; case Q_LAT: b1 = gen_linktype(ETHERTYPE_LAT); break; case Q_MOPDL: b1 = gen_linktype(ETHERTYPE_MOPDL); break; case Q_MOPRC: b1 = gen_linktype(ETHERTYPE_MOPRC); break; case Q_STP: b1 = gen_linktype(LLCSAP_8021D); break; #ifdef INET6 case Q_IPV6: b1 = gen_linktype(ETHERTYPE_IPV6); break; #ifndef IPPROTO_ICMPV6 #define IPPROTO_ICMPV6 58 #endif case Q_ICMPV6: b1 = gen_proto(IPPROTO_ICMPV6, Q_IPV6, Q_DEFAULT); break; #endif /* INET6 */ #ifndef IPPROTO_AH #define IPPROTO_AH 51 #endif case Q_AH: b1 = gen_proto(IPPROTO_AH, Q_IP, Q_DEFAULT); #ifdef INET6 b0 = gen_proto(IPPROTO_AH, Q_IPV6, Q_DEFAULT); gen_or(b0, b1); #endif break; #ifndef IPPROTO_ESP #define IPPROTO_ESP 50 #endif case Q_ESP: b1 = gen_proto(IPPROTO_ESP, Q_IP, Q_DEFAULT); #ifdef INET6 b0 = gen_proto(IPPROTO_ESP, Q_IPV6, Q_DEFAULT); gen_or(b0, b1); #endif break; default: abort(); } return b1; } static struct block * gen_ipfrag(void) { struct slist *s, *tmp; struct block *b; /* not ip frag */ if (variable_nl) { s = nl2X_stmt(); tmp = new_stmt(BPF_LD|BPF_H|BPF_IND); tmp->s.k = 6; sappend(s, tmp); } else { s = new_stmt(BPF_LD|BPF_H|BPF_ABS); s->s.k = off_nl + 6; } b = new_block(JMP(BPF_JSET)); b->s.k = 0x1fff; b->stmts = s; gen_not(b); return b; } /* For dynamic off_nl, the BPF_LDX|BPF_MSH instruction does not work This function generates code to set X to the start of the IP payload X = off_nl + IP header_len. */ static struct slist * iphl_to_x(void) { struct slist *s, *tmp; /* XXX clobbers A if variable_nl*/ if (variable_nl) { if (iphl_reg == -1) { /* X <- off_nl */ s = nl2X_stmt(); /* A = p[X+0] */ tmp = new_stmt(BPF_LD|BPF_B|BPF_IND); tmp->s.k = 0; sappend(s, tmp); /* A = A & 0x0f */ tmp = new_stmt(BPF_ALU|BPF_AND|BPF_K); tmp->s.k = 0x0f; sappend(s, tmp); /* A = A << 2 */ tmp = new_stmt(BPF_ALU|BPF_LSH|BPF_K); tmp->s.k = 2; sappend(s, tmp); /* A = A + X (add off_nl again to compensate) */ sappend(s, new_stmt(BPF_ALU|BPF_ADD|BPF_X)); /* MEM[iphl_reg] = A */ iphl_reg = alloc_reg(); tmp = new_stmt(BPF_ST); tmp->s.k = iphl_reg; sappend(s, tmp); sappend(init_code, s); } s = new_stmt(BPF_LDX|BPF_MEM); s->s.k = iphl_reg; } else { s = new_stmt(BPF_LDX|BPF_MSH|BPF_B); s->s.k = off_nl; } return s; } static struct block * gen_portatom(int off, bpf_int32 v) { struct slist *s, *tmp; struct block *b; s = iphl_to_x(); tmp = new_stmt(BPF_LD|BPF_IND|BPF_H); tmp->s.k = off_nl + off; /* off_nl == 0 if variable_nl */ sappend(s, tmp); b = new_block(JMP(BPF_JEQ)); b->stmts = s; b->s.k = v; return b; } #ifdef INET6 static struct block * gen_portatom6(int off, bpf_int32 v) { return gen_cmp_nl(40 + off, BPF_H, v); } #endif/*INET6*/ struct block * gen_portop(int port, int proto, int dir) { struct block *b0, *b1, *tmp; /* ip proto 'proto' */ tmp = gen_cmp_nl(9, BPF_B, (bpf_int32)proto); b0 = gen_ipfrag(); gen_and(tmp, b0); switch (dir) { case Q_SRC: b1 = gen_portatom(0, (bpf_int32)port); break; case Q_DST: b1 = gen_portatom(2, (bpf_int32)port); break; case Q_OR: case Q_DEFAULT: tmp = gen_portatom(0, (bpf_int32)port); b1 = gen_portatom(2, (bpf_int32)port); gen_or(tmp, b1); break; case Q_AND: tmp = gen_portatom(0, (bpf_int32)port); b1 = gen_portatom(2, (bpf_int32)port); gen_and(tmp, b1); break; default: abort(); } gen_and(b0, b1); return b1; } static struct block * gen_port(int port, int ip_proto, int dir) { struct block *b0, *b1, *tmp; /* ether proto ip */ b0 = gen_linktype(ETHERTYPE_IP); switch (ip_proto) { case IPPROTO_UDP: case IPPROTO_TCP: b1 = gen_portop(port, ip_proto, dir); break; case PROTO_UNDEF: tmp = gen_portop(port, IPPROTO_TCP, dir); b1 = gen_portop(port, IPPROTO_UDP, dir); gen_or(tmp, b1); break; default: abort(); } gen_and(b0, b1); return b1; } #ifdef INET6 struct block * gen_portop6(int port, int proto, int dir) { struct block *b0, *b1, *tmp; /* ip proto 'proto' */ b0 = gen_cmp_nl(6, BPF_B, (bpf_int32)proto); switch (dir) { case Q_SRC: b1 = gen_portatom6(0, (bpf_int32)port); break; case Q_DST: b1 = gen_portatom6(2, (bpf_int32)port); break; case Q_OR: case Q_DEFAULT: tmp = gen_portatom6(0, (bpf_int32)port); b1 = gen_portatom6(2, (bpf_int32)port); gen_or(tmp, b1); break; case Q_AND: tmp = gen_portatom6(0, (bpf_int32)port); b1 = gen_portatom6(2, (bpf_int32)port); gen_and(tmp, b1); break; default: abort(); } gen_and(b0, b1); return b1; } static struct block * gen_port6(int port, int ip_proto, int dir) { struct block *b0, *b1, *tmp; /* ether proto ip */ b0 = gen_linktype(ETHERTYPE_IPV6); switch (ip_proto) { case IPPROTO_UDP: case IPPROTO_TCP: b1 = gen_portop6(port, ip_proto, dir); break; case PROTO_UNDEF: tmp = gen_portop6(port, IPPROTO_TCP, dir); b1 = gen_portop6(port, IPPROTO_UDP, dir); gen_or(tmp, b1); break; default: abort(); } gen_and(b0, b1); return b1; } #endif /* INET6 */ static int lookup_proto(const char *name, int proto) { int v; switch (proto) { case Q_DEFAULT: case Q_IP: v = pcap_nametoproto(name); if (v == PROTO_UNDEF) bpf_error("unknown ip proto '%s'", name); break; case Q_LINK: /* XXX should look up h/w protocol type based on linktype */ v = pcap_nametoeproto(name); if (v == PROTO_UNDEF) { v = pcap_nametollc(name); if (v == PROTO_UNDEF) bpf_error("unknown ether proto '%s'", name); } break; default: v = PROTO_UNDEF; break; } return v; } static struct block * gen_protochain(int v, int proto, int dir) { struct block *b0, *b; struct slist *s[100]; int fix2, fix3, fix4, fix5; int ahcheck, again, end; int i, max; int reg1 = alloc_reg(); int reg2 = alloc_reg(); memset(s, 0, sizeof(s)); fix2 = fix3 = fix4 = fix5 = 0; if (variable_nl) { bpf_error("'gen_protochain' not supported for variable DLTs"); /*NOTREACHED*/ } switch (proto) { case Q_IP: case Q_IPV6: break; case Q_DEFAULT: b0 = gen_protochain(v, Q_IP, dir); b = gen_protochain(v, Q_IPV6, dir); gen_or(b0, b); return b; default: bpf_error("bad protocol applied for 'protochain'"); /*NOTREACHED*/ } no_optimize = 1; /*this code is not compatible with optimzer yet */ /* * s[0] is a dummy entry to protect other BPF insn from damaged * by s[fix] = foo with uninitialized variable "fix". It is somewhat * hard to find interdependency made by jump table fixup. */ i = 0; s[i] = new_stmt(0); /*dummy*/ i++; switch (proto) { case Q_IP: b0 = gen_linktype(ETHERTYPE_IP); /* A = ip->ip_p */ s[i] = new_stmt(BPF_LD|BPF_ABS|BPF_B); s[i]->s.k = off_nl + 9; i++; /* X = ip->ip_hl << 2 */ s[i] = new_stmt(BPF_LDX|BPF_MSH|BPF_B); s[i]->s.k = off_nl; i++; break; case Q_IPV6: b0 = gen_linktype(ETHERTYPE_IPV6); /* A = ip6->ip_nxt */ s[i] = new_stmt(BPF_LD|BPF_ABS|BPF_B); s[i]->s.k = off_nl + 6; i++; /* X = sizeof(struct ip6_hdr) */ s[i] = new_stmt(BPF_LDX|BPF_IMM); s[i]->s.k = 40; i++; break; default: bpf_error("unsupported proto to gen_protochain"); /*NOTREACHED*/ } /* again: if (A == v) goto end; else fall through; */ again = i; s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K); s[i]->s.k = v; s[i]->s.jt = NULL; /*later*/ s[i]->s.jf = NULL; /*update in next stmt*/ fix5 = i; i++; /* if (A == IPPROTO_NONE) goto end */ s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K); s[i]->s.jt = NULL; /*later*/ s[i]->s.jf = NULL; /*update in next stmt*/ s[i]->s.k = IPPROTO_NONE; s[fix5]->s.jf = s[i]; fix2 = i; i++; if (proto == Q_IPV6) { int v6start, v6end, v6advance, j; v6start = i; /* if (A == IPPROTO_HOPOPTS) goto v6advance */ s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K); s[i]->s.jt = NULL; /*later*/ s[i]->s.jf = NULL; /*update in next stmt*/ s[i]->s.k = IPPROTO_HOPOPTS; s[fix2]->s.jf = s[i]; i++; /* if (A == IPPROTO_DSTOPTS) goto v6advance */ s[i - 1]->s.jf = s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K); s[i]->s.jt = NULL; /*later*/ s[i]->s.jf = NULL; /*update in next stmt*/ s[i]->s.k = IPPROTO_DSTOPTS; i++; /* if (A == IPPROTO_ROUTING) goto v6advance */ s[i - 1]->s.jf = s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K); s[i]->s.jt = NULL; /*later*/ s[i]->s.jf = NULL; /*update in next stmt*/ s[i]->s.k = IPPROTO_ROUTING; i++; /* if (A == IPPROTO_FRAGMENT) goto v6advance; else goto ahcheck; */ s[i - 1]->s.jf = s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K); s[i]->s.jt = NULL; /*later*/ s[i]->s.jf = NULL; /*later*/ s[i]->s.k = IPPROTO_FRAGMENT; fix3 = i; v6end = i; i++; /* v6advance: */ v6advance = i; /* * in short, * A = P[X + 1]; * X = X + (P[X] + 1) * 8; */ /* A = X */ s[i] = new_stmt(BPF_MISC|BPF_TXA); i++; /* MEM[reg1] = A */ s[i] = new_stmt(BPF_ST); s[i]->s.k = reg1; i++; /* A += 1 */ s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K); s[i]->s.k = 1; i++; /* X = A */ s[i] = new_stmt(BPF_MISC|BPF_TAX); i++; /* A = P[X + packet head]; */ s[i] = new_stmt(BPF_LD|BPF_IND|BPF_B); s[i]->s.k = off_nl; i++; /* MEM[reg2] = A */ s[i] = new_stmt(BPF_ST); s[i]->s.k = reg2; i++; /* X = MEM[reg1] */ s[i] = new_stmt(BPF_LDX|BPF_MEM); s[i]->s.k = reg1; i++; /* A = P[X + packet head] */ s[i] = new_stmt(BPF_LD|BPF_IND|BPF_B); s[i]->s.k = off_nl; i++; /* A += 1 */ s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K); s[i]->s.k = 1; i++; /* A *= 8 */ s[i] = new_stmt(BPF_ALU|BPF_MUL|BPF_K); s[i]->s.k = 8; i++; /* X = A; */ s[i] = new_stmt(BPF_MISC|BPF_TAX); i++; /* A = MEM[reg2] */ s[i] = new_stmt(BPF_LD|BPF_MEM); s[i]->s.k = reg2; i++; /* goto again; (must use BPF_JA for backward jump) */ s[i] = new_stmt(BPF_JMP|BPF_JA); s[i]->s.k = again - i - 1; s[i - 1]->s.jf = s[i]; i++; /* fixup */ for (j = v6start; j <= v6end; j++) s[j]->s.jt = s[v6advance]; } else { /* nop */ s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K); s[i]->s.k = 0; s[fix2]->s.jf = s[i]; i++; } /* ahcheck: */ ahcheck = i; /* if (A == IPPROTO_AH) then fall through; else goto end; */ s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K); s[i]->s.jt = NULL; /*later*/ s[i]->s.jf = NULL; /*later*/ s[i]->s.k = IPPROTO_AH; if (fix3) s[fix3]->s.jf = s[ahcheck]; fix4 = i; i++; /* * in short, * A = P[X + 1]; * X = X + (P[X] + 2) * 4; */ /* A = X */ s[i - 1]->s.jt = s[i] = new_stmt(BPF_MISC|BPF_TXA); i++; /* MEM[reg1] = A */ s[i] = new_stmt(BPF_ST); s[i]->s.k = reg1; i++; /* A += 1 */ s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K); s[i]->s.k = 1; i++; /* X = A */ s[i] = new_stmt(BPF_MISC|BPF_TAX); i++; /* A = P[X + packet head]; */ s[i] = new_stmt(BPF_LD|BPF_IND|BPF_B); s[i]->s.k = off_nl; i++; /* MEM[reg2] = A */ s[i] = new_stmt(BPF_ST); s[i]->s.k = reg2; i++; /* X = MEM[reg1] */ s[i] = new_stmt(BPF_LDX|BPF_MEM); s[i]->s.k = reg1; i++; /* A = P[X + packet head] */ s[i] = new_stmt(BPF_LD|BPF_IND|BPF_B); s[i]->s.k = off_nl; i++; /* A += 2 */ s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K); s[i]->s.k = 2; i++; /* A *= 4 */ s[i] = new_stmt(BPF_ALU|BPF_MUL|BPF_K); s[i]->s.k = 4; i++; /* X = A; */ s[i] = new_stmt(BPF_MISC|BPF_TAX); i++; /* A = MEM[reg2] */ s[i] = new_stmt(BPF_LD|BPF_MEM); s[i]->s.k = reg2; i++; /* goto again; (must use BPF_JA for backward jump) */ s[i] = new_stmt(BPF_JMP|BPF_JA); s[i]->s.k = again - i - 1; i++; /* end: nop */ end = i; s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K); s[i]->s.k = 0; s[fix2]->s.jt = s[end]; s[fix4]->s.jf = s[end]; s[fix5]->s.jt = s[end]; i++; /* * make slist chain */ max = i; for (i = 0; i < max - 1; i++) s[i]->next = s[i + 1]; s[max - 1]->next = NULL; /* * emit final check */ b = new_block(JMP(BPF_JEQ)); b->stmts = s[1]; /*remember, s[0] is dummy*/ b->s.k = v; free_reg(reg1); free_reg(reg2); gen_and(b0, b); return b; } static struct block * gen_proto(int v, int proto, int dir) { struct block *b0, *b1; if (dir != Q_DEFAULT) bpf_error("direction applied to 'proto'"); switch (proto) { case Q_DEFAULT: #ifdef INET6 b0 = gen_proto(v, Q_IP, dir); b1 = gen_proto(v, Q_IPV6, dir); gen_or(b0, b1); return b1; #else /*FALLTHROUGH*/ #endif case Q_IP: b0 = gen_linktype(ETHERTYPE_IP); #ifndef CHASE_CHAIN b1 = gen_cmp_nl(9, BPF_B, (bpf_int32)v); #else b1 = gen_protochain(v, Q_IP); #endif gen_and(b0, b1); return b1; case Q_ARP: bpf_error("arp does not encapsulate another protocol"); /* NOTREACHED */ case Q_RARP: bpf_error("rarp does not encapsulate another protocol"); /* NOTREACHED */ case Q_ATALK: bpf_error("atalk encapsulation is not specifiable"); /* NOTREACHED */ case Q_DECNET: bpf_error("decnet encapsulation is not specifiable"); /* NOTREACHED */ case Q_SCA: bpf_error("sca does not encapsulate another protocol"); /* NOTREACHED */ case Q_LAT: bpf_error("lat does not encapsulate another protocol"); /* NOTREACHED */ case Q_MOPRC: bpf_error("moprc does not encapsulate another protocol"); /* NOTREACHED */ case Q_MOPDL: bpf_error("mopdl does not encapsulate another protocol"); /* NOTREACHED */ case Q_LINK: return gen_linktype(v); case Q_UDP: bpf_error("'udp proto' is bogus"); /* NOTREACHED */ case Q_TCP: bpf_error("'tcp proto' is bogus"); /* NOTREACHED */ case Q_ICMP: bpf_error("'icmp proto' is bogus"); /* NOTREACHED */ case Q_IGMP: bpf_error("'igmp proto' is bogus"); /* NOTREACHED */ case Q_IGRP: bpf_error("'igrp proto' is bogus"); /* NOTREACHED */ case Q_PIM: bpf_error("'pim proto' is bogus"); /* NOTREACHED */ case Q_STP: bpf_error("'stp proto' is bogus"); /* NOTREACHED */ #ifdef INET6 case Q_IPV6: b0 = gen_linktype(ETHERTYPE_IPV6); #ifndef CHASE_CHAIN b1 = gen_cmp_nl(6, BPF_B, (bpf_int32)v); #else b1 = gen_protochain(v, Q_IPV6); #endif gen_and(b0, b1); return b1; case Q_ICMPV6: bpf_error("'icmp6 proto' is bogus"); #endif /* INET6 */ case Q_AH: bpf_error("'ah proto' is bogus"); case Q_ESP: bpf_error("'esp proto' is bogus"); default: abort(); /* NOTREACHED */ } /* NOTREACHED */ } struct block * gen_scode(const char *name, struct qual q) { int proto = q.proto; int dir = q.dir; int tproto; u_char *eaddr; bpf_u_int32 mask, addr; #ifndef INET6 bpf_u_int32 **alist; #else int tproto6; struct sockaddr_in *sin; struct sockaddr_in6 *sin6; struct addrinfo *res, *res0; struct in6_addr mask128; #endif /*INET6*/ struct block *b, *tmp; int port, real_proto; switch (q.addr) { case Q_NET: addr = pcap_nametonetaddr(name); if (addr == 0) bpf_error("unknown network '%s'", name); /* Left justify network addr and calculate its network mask */ mask = 0xffffffff; while (addr && (addr & 0xff000000) == 0) { addr <<= 8; mask <<= 8; } return gen_host(addr, mask, proto, dir); case Q_DEFAULT: case Q_HOST: if (proto == Q_LINK) { switch (linktype) { case DLT_EN10MB: eaddr = pcap_ether_hostton(name); if (eaddr == NULL) bpf_error( "unknown ether host '%s'", name); return gen_ehostop(eaddr, dir); case DLT_FDDI: eaddr = pcap_ether_hostton(name); if (eaddr == NULL) bpf_error( "unknown FDDI host '%s'", name); return gen_fhostop(eaddr, dir); case DLT_IEEE802_11: case DLT_IEEE802_11_RADIO: eaddr = pcap_ether_hostton(name); if (eaddr == NULL) bpf_error( "unknown 802.11 host '%s'", name); return gen_p80211_hostop(eaddr, dir); default: bpf_error( "only ethernet/FDDI supports link-level host name"); break; } } else if (proto == Q_DECNET) { unsigned short dn_addr = __pcap_nametodnaddr(name); /* * I don't think DECNET hosts can be multihomed, so * there is no need to build up a list of addresses */ return (gen_host(dn_addr, 0, proto, dir)); } else { #ifndef INET6 alist = pcap_nametoaddr(name); if (alist == NULL || *alist == NULL) bpf_error("unknown host '%s'", name); tproto = proto; if (off_linktype == -1 && tproto == Q_DEFAULT) tproto = Q_IP; b = gen_host(**alist++, 0xffffffff, tproto, dir); while (*alist) { tmp = gen_host(**alist++, 0xffffffff, tproto, dir); gen_or(b, tmp); b = tmp; } return b; #else memset(&mask128, 0xff, sizeof(mask128)); res0 = res = pcap_nametoaddrinfo(name); if (res == NULL) bpf_error("unknown host '%s'", name); b = tmp = NULL; tproto = tproto6 = proto; if (off_linktype == -1 && tproto == Q_DEFAULT) { tproto = Q_IP; tproto6 = Q_IPV6; } for (res = res0; res; res = res->ai_next) { switch (res->ai_family) { case AF_INET: if (tproto == Q_IPV6) continue; sin = (struct sockaddr_in *) res->ai_addr; tmp = gen_host(ntohl(sin->sin_addr.s_addr), 0xffffffff, tproto, dir); break; case AF_INET6: if (tproto6 == Q_IP) continue; sin6 = (struct sockaddr_in6 *) res->ai_addr; tmp = gen_host6(&sin6->sin6_addr, &mask128, tproto6, dir); break; } if (b) gen_or(b, tmp); b = tmp; } freeaddrinfo(res0); if (b == NULL) { bpf_error("unknown host '%s'%s", name, (proto == Q_DEFAULT) ? "" : " for specified address family"); } return b; #endif /*INET6*/ } case Q_PORT: if (proto != Q_DEFAULT && proto != Q_UDP && proto != Q_TCP) bpf_error("illegal qualifier of 'port'"); if (pcap_nametoport(name, &port, &real_proto) == 0) bpf_error("unknown port '%s'", name); if (proto == Q_UDP) { if (real_proto == IPPROTO_TCP) bpf_error("port '%s' is tcp", name); else /* override PROTO_UNDEF */ real_proto = IPPROTO_UDP; } if (proto == Q_TCP) { if (real_proto == IPPROTO_UDP) bpf_error("port '%s' is udp", name); else /* override PROTO_UNDEF */ real_proto = IPPROTO_TCP; } #ifndef INET6 return gen_port(port, real_proto, dir); #else { struct block *b; b = gen_port(port, real_proto, dir); gen_or(gen_port6(port, real_proto, dir), b); return b; } #endif /* INET6 */ case Q_GATEWAY: #ifndef INET6 eaddr = pcap_ether_hostton(name); if (eaddr == NULL) bpf_error("unknown ether host: %s", name); alist = pcap_nametoaddr(name); if (alist == NULL || *alist == NULL) bpf_error("unknown host '%s'", name); return gen_gateway(eaddr, alist, proto, dir); #else bpf_error("'gateway' not supported in this configuration"); #endif /*INET6*/ case Q_PROTO: real_proto = lookup_proto(name, proto); if (real_proto >= 0) return gen_proto(real_proto, proto, dir); else bpf_error("unknown protocol: %s", name); case Q_PROTOCHAIN: real_proto = lookup_proto(name, proto); if (real_proto >= 0) return gen_protochain(real_proto, proto, dir); else bpf_error("unknown protocol: %s", name); case Q_UNDEF: syntax(); /* NOTREACHED */ } abort(); /* NOTREACHED */ } struct block * gen_mcode(const char *s1, const char *s2, int masklen, struct qual q) { int nlen, mlen; bpf_u_int32 n, m; nlen = __pcap_atoin(s1, &n); /* Promote short ipaddr */ n <<= 32 - nlen; if (s2 != NULL) { mlen = __pcap_atoin(s2, &m); /* Promote short ipaddr */ m <<= 32 - mlen; if ((n & ~m) != 0) bpf_error("non-network bits set in \"%s mask %s\"", s1, s2); } else { /* Convert mask len to mask */ if (masklen > 32) bpf_error("mask length must be <= 32"); m = 0xffffffff << (32 - masklen); if ((n & ~m) != 0) bpf_error("non-network bits set in \"%s/%d\"", s1, masklen); } switch (q.addr) { case Q_NET: return gen_host(n, m, q.proto, q.dir); default: bpf_error("Mask syntax for networks only"); /* NOTREACHED */ } } struct block * gen_ncode(const char *s, bpf_u_int32 v, struct qual q) { bpf_u_int32 mask; int proto = q.proto; int dir = q.dir; int vlen; if (s == NULL) vlen = 32; else if (q.proto == Q_DECNET) vlen = __pcap_atodn(s, &v); else vlen = __pcap_atoin(s, &v); switch (q.addr) { case Q_DEFAULT: case Q_HOST: case Q_NET: if (proto == Q_DECNET) return gen_host(v, 0, proto, dir); else if (proto == Q_LINK) { bpf_error("illegal link layer address"); } else { mask = 0xffffffff; if (s == NULL && q.addr == Q_NET) { /* Promote short net number */ while (v && (v & 0xff000000) == 0) { v <<= 8; mask <<= 8; } } else { /* Promote short ipaddr */ v <<= 32 - vlen; mask <<= 32 - vlen; } return gen_host(v, mask, proto, dir); } case Q_PORT: if (proto == Q_UDP) proto = IPPROTO_UDP; else if (proto == Q_TCP) proto = IPPROTO_TCP; else if (proto == Q_DEFAULT) proto = PROTO_UNDEF; else bpf_error("illegal qualifier of 'port'"); #ifndef INET6 return gen_port((int)v, proto, dir); #else { struct block *b; b = gen_port((int)v, proto, dir); gen_or(gen_port6((int)v, proto, dir), b); return b; } #endif /* INET6 */ case Q_GATEWAY: bpf_error("'gateway' requires a name"); /* NOTREACHED */ case Q_PROTO: return gen_proto((int)v, proto, dir); case Q_PROTOCHAIN: return gen_protochain((int)v, proto, dir); case Q_UNDEF: syntax(); /* NOTREACHED */ default: abort(); /* NOTREACHED */ } /* NOTREACHED */ } #ifdef INET6 struct block * gen_mcode6(const char *s1, const char *s2, int masklen, struct qual q) { struct addrinfo *res; struct in6_addr *addr; struct in6_addr mask; struct block *b; u_int32_t *a, *m; if (s2) bpf_error("no mask %s supported", s2); res = pcap_nametoaddrinfo(s1); if (!res) bpf_error("invalid ip6 address %s", s1); if (res->ai_next) bpf_error("%s resolved to multiple address", s1); addr = &((struct sockaddr_in6 *)res->ai_addr)->sin6_addr; if (sizeof(mask) * 8 < masklen) bpf_error("mask length must be <= %u", (unsigned int)(sizeof(mask) * 8)); memset(&mask, 0, sizeof(mask)); memset(&mask, 0xff, masklen / 8); if (masklen % 8) { mask.s6_addr[masklen / 8] = (0xff << (8 - masklen % 8)) & 0xff; } a = (u_int32_t *)addr; m = (u_int32_t *)&mask; if ((a[0] & ~m[0]) || (a[1] & ~m[1]) || (a[2] & ~m[2]) || (a[3] & ~m[3])) { bpf_error("non-network bits set in \"%s/%d\"", s1, masklen); } switch (q.addr) { case Q_DEFAULT: case Q_HOST: if (masklen != 128) bpf_error("Mask syntax for networks only"); /* FALLTHROUGH */ case Q_NET: b = gen_host6(addr, &mask, q.proto, q.dir); freeaddrinfo(res); return b; default: bpf_error("invalid qualifier against IPv6 address"); /* NOTREACHED */ } } #endif /*INET6*/ struct block * gen_ecode(const u_char *eaddr, struct qual q) { if ((q.addr == Q_HOST || q.addr == Q_DEFAULT) && q.proto == Q_LINK) { if (linktype == DLT_EN10MB) return gen_ehostop(eaddr, (int)q.dir); if (linktype == DLT_FDDI) return gen_fhostop(eaddr, (int)q.dir); if (linktype == DLT_IEEE802_11 || linktype == DLT_IEEE802_11_RADIO) return gen_p80211_hostop(eaddr, (int)q.dir); } bpf_error("ethernet address used in non-ether expression"); /* NOTREACHED */ } void sappend(struct slist *s0, struct slist *s1) { /* * This is definitely not the best way to do this, but the * lists will rarely get long. */ while (s0->next) s0 = s0->next; s0->next = s1; } static struct slist * xfer_to_x(struct arth *a) { struct slist *s; s = new_stmt(BPF_LDX|BPF_MEM); s->s.k = a->regno; return s; } static struct slist * xfer_to_a(struct arth *a) { struct slist *s; s = new_stmt(BPF_LD|BPF_MEM); s->s.k = a->regno; return s; } struct arth * gen_load(int proto, struct arth *index, int size) { struct slist *s, *tmp; struct block *b; int regno = alloc_reg(); free_reg(index->regno); switch (size) { default: bpf_error("data size must be 1, 2, or 4"); case 1: size = BPF_B; break; case 2: size = BPF_H; break; case 4: size = BPF_W; break; } switch (proto) { default: bpf_error("unsupported index operation"); case Q_LINK: s = xfer_to_x(index); tmp = new_stmt(BPF_LD|BPF_IND|size); sappend(s, tmp); sappend(index->s, s); break; case Q_IP: case Q_ARP: case Q_RARP: case Q_ATALK: case Q_DECNET: case Q_SCA: case Q_LAT: case Q_MOPRC: case Q_MOPDL: #ifdef INET6 case Q_IPV6: #endif /* XXX Note that we assume a fixed link header here. */ if (variable_nl) { s = nl2X_stmt(); sappend(s, xfer_to_a(index)); sappend(s, new_stmt(BPF_ALU|BPF_ADD|BPF_X)); sappend(s, new_stmt(BPF_MISC|BPF_TAX)); } else { s = xfer_to_x(index); } tmp = new_stmt(BPF_LD|BPF_IND|size); tmp->s.k = off_nl; /* off_nl == 0 for variable_nl */ sappend(s, tmp); sappend(index->s, s); b = gen_proto_abbrev(proto); if (index->b) gen_and(index->b, b); index->b = b; break; case Q_TCP: case Q_UDP: case Q_ICMP: case Q_IGMP: case Q_IGRP: case Q_PIM: s = iphl_to_x(); sappend(s, xfer_to_a(index)); sappend(s, new_stmt(BPF_ALU|BPF_ADD|BPF_X)); sappend(s, new_stmt(BPF_MISC|BPF_TAX)); sappend(s, tmp = new_stmt(BPF_LD|BPF_IND|size)); tmp->s.k = off_nl; /* off_nl is 0 if variable_nl */ sappend(index->s, s); gen_and(gen_proto_abbrev(proto), b = gen_ipfrag()); if (index->b) gen_and(index->b, b); #ifdef INET6 gen_and(gen_proto_abbrev(Q_IP), b); #endif index->b = b; break; #ifdef INET6 case Q_ICMPV6: bpf_error("IPv6 upper-layer protocol is not supported by proto[x]"); /*NOTREACHED*/ #endif } index->regno = regno; s = new_stmt(BPF_ST); s->s.k = regno; sappend(index->s, s); return index; } struct block * gen_relation(int code, struct arth *a0, struct arth *a1, int reversed) { struct slist *s0, *s1, *s2; struct block *b, *tmp; s0 = xfer_to_x(a1); s1 = xfer_to_a(a0); s2 = new_stmt(BPF_ALU|BPF_SUB|BPF_X); b = new_block(JMP(code)); if (code == BPF_JGT || code == BPF_JGE) { reversed = !reversed; b->s.k = 0x80000000; } if (reversed) gen_not(b); sappend(s1, s2); sappend(s0, s1); sappend(a1->s, s0); sappend(a0->s, a1->s); b->stmts = a0->s; free_reg(a0->regno); free_reg(a1->regno); /* 'and' together protocol checks */ if (a0->b) { if (a1->b) { gen_and(a0->b, tmp = a1->b); } else tmp = a0->b; } else tmp = a1->b; if (tmp) gen_and(tmp, b); return b; } struct arth * gen_loadlen(void) { int regno = alloc_reg(); struct arth *a = (struct arth *)newchunk(sizeof(*a)); struct slist *s; s = new_stmt(BPF_LD|BPF_LEN); s->next = new_stmt(BPF_ST); s->next->s.k = regno; a->s = s; a->regno = regno; return a; } struct arth * gen_loadrnd(void) { int regno = alloc_reg(); struct arth *a = (struct arth *)newchunk(sizeof(*a)); struct slist *s; s = new_stmt(BPF_LD|BPF_RND); s->next = new_stmt(BPF_ST); s->next->s.k = regno; a->s = s; a->regno = regno; return a; } struct arth * gen_loadi(int val) { struct arth *a; struct slist *s; int reg; a = (struct arth *)newchunk(sizeof(*a)); reg = alloc_reg(); s = new_stmt(BPF_LD|BPF_IMM); s->s.k = val; s->next = new_stmt(BPF_ST); s->next->s.k = reg; a->s = s; a->regno = reg; return a; } struct arth * gen_neg(struct arth *a) { struct slist *s; s = xfer_to_a(a); sappend(a->s, s); s = new_stmt(BPF_ALU|BPF_NEG); s->s.k = 0; sappend(a->s, s); s = new_stmt(BPF_ST); s->s.k = a->regno; sappend(a->s, s); return a; } struct arth * gen_arth(int code, struct arth *a0, struct arth *a1) { struct slist *s0, *s1, *s2; s0 = xfer_to_x(a1); s1 = xfer_to_a(a0); s2 = new_stmt(BPF_ALU|BPF_X|code); sappend(s1, s2); sappend(s0, s1); sappend(a1->s, s0); sappend(a0->s, a1->s); free_reg(a1->regno); s0 = new_stmt(BPF_ST); a0->regno = s0->s.k = alloc_reg(); sappend(a0->s, s0); return a0; } /* * Here we handle simple allocation of the scratch registers. * If too many registers are alloc'd, the allocator punts. */ static int regused[BPF_MEMWORDS]; static int curreg; /* * Return the next free register. */ static int alloc_reg(void) { int n = BPF_MEMWORDS; while (--n >= 0) { if (regused[curreg]) curreg = (curreg + 1) % BPF_MEMWORDS; else { regused[curreg] = 1; return curreg; } } bpf_error("too many registers needed to evaluate expression"); /* NOTREACHED */ } /* * Return a register to the table so it can * be used later. */ static void free_reg(int n) { regused[n] = 0; } static struct block * gen_len(int jmp, int n) { struct slist *s; struct block *b; s = new_stmt(BPF_LD|BPF_LEN); b = new_block(JMP(jmp)); b->stmts = s; b->s.k = n; return b; } struct block * gen_greater(int n) { return gen_len(BPF_JGE, n); } struct block * gen_less(int n) { struct block *b; b = gen_len(BPF_JGT, n); gen_not(b); return b; } struct block * gen_byteop(int op, int idx, int val) { struct block *b; struct slist *s; switch (op) { default: abort(); case '=': return gen_cmp((u_int)idx, BPF_B, (bpf_int32)val); case '<': b = gen_cmp((u_int)idx, BPF_B, (bpf_int32)val); b->s.code = JMP(BPF_JGE); gen_not(b); return b; case '>': b = gen_cmp((u_int)idx, BPF_B, (bpf_int32)val); b->s.code = JMP(BPF_JGT); return b; case '|': s = new_stmt(BPF_ALU|BPF_OR|BPF_K); break; case '&': s = new_stmt(BPF_ALU|BPF_AND|BPF_K); break; } s->s.k = val; b = new_block(JMP(BPF_JEQ)); b->stmts = s; gen_not(b); return b; } struct block * gen_broadcast(int proto) { bpf_u_int32 hostmask; struct block *b0, *b1, *b2; static u_char ebroadcast[] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff }; switch (proto) { case Q_DEFAULT: case Q_LINK: if (linktype == DLT_EN10MB) return gen_ehostop(ebroadcast, Q_DST); if (linktype == DLT_FDDI) return gen_fhostop(ebroadcast, Q_DST); if (linktype == DLT_IEEE802_11 || linktype == DLT_IEEE802_11_RADIO) return gen_p80211_hostop(ebroadcast, Q_DST); bpf_error("not a broadcast link"); break; case Q_IP: /* * We treat a netmask of PCAP_NETMASK_UNKNOWN (0xffffffff) * as an indication that we don't know the netmask, and fail * in that case. */ if (netmask == PCAP_NETMASK_UNKNOWN) bpf_error("netmask not known, so 'ip broadcast' not supported"); b0 = gen_linktype(ETHERTYPE_IP); hostmask = ~netmask; b1 = gen_mcmp_nl(16, BPF_W, (bpf_int32)0, hostmask); b2 = gen_mcmp_nl(16, BPF_W, (bpf_int32)(~0 & hostmask), hostmask); gen_or(b1, b2); gen_and(b0, b2); return b2; } bpf_error("only ether/ip broadcast filters supported"); } struct block * gen_multicast(int proto) { struct block *b0, *b1; struct slist *s; switch (proto) { case Q_DEFAULT: case Q_LINK: if (linktype == DLT_EN10MB) { /* ether[0] & 1 != 0 */ s = new_stmt(BPF_LD|BPF_B|BPF_ABS); s->s.k = 0; b0 = new_block(JMP(BPF_JSET)); b0->s.k = 1; b0->stmts = s; return b0; } if (linktype == DLT_FDDI) { /* XXX TEST THIS: MIGHT NOT PORT PROPERLY XXX */ /* fddi[1] & 1 != 0 */ s = new_stmt(BPF_LD|BPF_B|BPF_ABS); s->s.k = 1; b0 = new_block(JMP(BPF_JSET)); b0->s.k = 1; b0->stmts = s; return b0; } /* Link not known to support multicasts */ break; case Q_IP: b0 = gen_linktype(ETHERTYPE_IP); b1 = gen_cmp_nl(16, BPF_B, (bpf_int32)224); b1->s.code = JMP(BPF_JGE); gen_and(b0, b1); return b1; #ifdef INET6 case Q_IPV6: b0 = gen_linktype(ETHERTYPE_IPV6); b1 = gen_cmp_nl(24, BPF_B, (bpf_int32)255); gen_and(b0, b1); return b1; #endif /* INET6 */ } bpf_error("only IP multicast filters supported on ethernet/FDDI"); } /* * generate command for inbound/outbound. It's here so we can * make it link-type specific. 'dir' = 0 implies "inbound", * = 1 implies "outbound". */ struct block * gen_inbound(int dir) { struct block *b0; /* * Only SLIP and old-style PPP data link types support * inbound/outbound qualifiers. */ switch (linktype) { case DLT_SLIP: case DLT_PPP: b0 = gen_relation(BPF_JEQ, gen_load(Q_LINK, gen_loadi(0), 1), gen_loadi(0), dir); break; case DLT_PFLOG: b0 = gen_cmp(offsetof(struct pfloghdr, dir), BPF_B, (bpf_int32)((dir == 0) ? PF_IN : PF_OUT)); break; default: bpf_error("inbound/outbound not supported on linktype 0x%x", linktype); /* NOTREACHED */ } return (b0); } /* PF firewall log matched interface */ struct block * gen_pf_ifname(char *ifname) { struct block *b0; u_int len, off; if (linktype == DLT_PFLOG) { len = sizeof(((struct pfloghdr *)0)->ifname); off = offsetof(struct pfloghdr, ifname); } else { bpf_error("ifname not supported on linktype 0x%x", linktype); /* NOTREACHED */ } if (strlen(ifname) >= len) { bpf_error("ifname interface names can only be %d characters", len - 1); /* NOTREACHED */ } b0 = gen_bcmp(off, strlen(ifname) + 1, ifname); return (b0); } /* PF firewall log ruleset name */ struct block * gen_pf_ruleset(char *ruleset) { struct block *b0; if (linktype != DLT_PFLOG) { bpf_error("ruleset not supported on linktype 0x%x", linktype); /* NOTREACHED */ } if (strlen(ruleset) >= sizeof(((struct pfloghdr *)0)->ruleset)) { bpf_error("ruleset names can only be %zu characters", sizeof(((struct pfloghdr *)0)->ruleset) - 1); /* NOTREACHED */ } b0 = gen_bcmp(offsetof(struct pfloghdr, ruleset), strlen(ruleset), ruleset); return (b0); } /* PF firewall log rule number */ struct block * gen_pf_rnr(int rnr) { struct block *b0; if (linktype == DLT_PFLOG) { b0 = gen_cmp(offsetof(struct pfloghdr, rulenr), BPF_W, (bpf_int32)rnr); } else { bpf_error("rnr not supported on linktype 0x%x", linktype); /* NOTREACHED */ } return (b0); } /* PF firewall log sub-rule number */ struct block * gen_pf_srnr(int srnr) { struct block *b0; if (linktype != DLT_PFLOG) { bpf_error("srnr not supported on linktype 0x%x", linktype); /* NOTREACHED */ } b0 = gen_cmp(offsetof(struct pfloghdr, subrulenr), BPF_W, (bpf_int32)srnr); return (b0); } /* PF firewall log reason code */ struct block * gen_pf_reason(int reason) { struct block *b0; if (linktype == DLT_PFLOG) { b0 = gen_cmp(offsetof(struct pfloghdr, reason), BPF_B, (bpf_int32)reason); } else { bpf_error("reason not supported on linktype 0x%x", linktype); /* NOTREACHED */ } return (b0); } /* PF firewall log action */ struct block * gen_pf_action(int action) { struct block *b0; if (linktype == DLT_PFLOG) { b0 = gen_cmp(offsetof(struct pfloghdr, action), BPF_B, (bpf_int32)action); } else { bpf_error("action not supported on linktype 0x%x", linktype); /* NOTREACHED */ } return (b0); } /* IEEE 802.11 wireless header */ struct block * gen_p80211_type(int type, int mask) { struct block *b0; u_int offset; if (!(linktype == DLT_IEEE802_11 || linktype == DLT_IEEE802_11_RADIO)) { bpf_error("type not supported on linktype 0x%x", linktype); /* NOTREACHED */ } offset = (u_int)offsetof(struct ieee80211_frame, i_fc[0]); if (linktype == DLT_IEEE802_11_RADIO) offset += IEEE80211_RADIOTAP_HDRLEN; b0 = gen_mcmp(offset, BPF_B, (bpf_int32)type, (bpf_u_int32)mask); return (b0); } static struct block * gen_ahostop(const u_char *eaddr, int dir) { struct block *b0, *b1; switch (dir) { /* src comes first, different from Ethernet */ case Q_SRC: return gen_bcmp(0, 1, eaddr); case Q_DST: return gen_bcmp(1, 1, eaddr); case Q_AND: b0 = gen_ahostop(eaddr, Q_SRC); b1 = gen_ahostop(eaddr, Q_DST); gen_and(b0, b1); return b1; case Q_DEFAULT: case Q_OR: b0 = gen_ahostop(eaddr, Q_SRC); b1 = gen_ahostop(eaddr, Q_DST); gen_or(b0, b1); return b1; } abort(); /* NOTREACHED */ } struct block * gen_acode(const u_char *eaddr, struct qual q) { if ((q.addr == Q_HOST || q.addr == Q_DEFAULT) && q.proto == Q_LINK) { if (linktype == DLT_ARCNET) return gen_ahostop(eaddr, (int)q.dir); } bpf_error("ARCnet address used in non-arc expression"); /* NOTREACHED */ } struct block * gen_mpls(int label) { struct block *b0; if (label > MPLS_LABEL_MAX) bpf_error("invalid MPLS label : %d", label); if (mpls_stack > 0) /* Bottom-Of-Label-Stack bit ? */ b0 = gen_mcmp(off_nl-2, BPF_B, (bpf_int32)0, 0x1); else b0 = gen_linktype(ETHERTYPE_MPLS); if (label >= 0) { struct block *b1; b1 = gen_mcmp(off_nl, BPF_W, (bpf_int32)(label << 12), MPLS_LABEL_MASK); gen_and(b0, b1); b0 = b1; } off_nl += 4; off_linktype += 4; mpls_stack++; return (b0); } /* * support IEEE 802.1Q VLAN trunk over ethernet */ struct block * gen_vlan(int vlan_num) { struct block *b0; if (variable_nl) { bpf_error("'vlan' not supported for variable DLTs"); /*NOTREACHED*/ } if (vlan_num > 4095) { bpf_error("invalid VLAN number : %d", vlan_num); /*NOTREACHED*/ } /* * Change the offsets to point to the type and data fields within * the VLAN packet. This is somewhat of a kludge. */ if (orig_nl == (u_int)-1) { orig_linktype = off_linktype; /* save original values */ orig_nl = off_nl; orig_nl_nosnap = off_nl_nosnap; switch (linktype) { case DLT_EN10MB: off_linktype = 16; off_nl_nosnap = 18; off_nl = 18; break; default: bpf_error("no VLAN support for data link type %d", linktype); /*NOTREACHED*/ } } /* check for VLAN */ b0 = gen_cmp(orig_linktype, BPF_H, (bpf_int32)ETHERTYPE_8021Q); /* If a specific VLAN is requested, check VLAN id */ if (vlan_num >= 0) { struct block *b1; b1 = gen_mcmp(orig_nl, BPF_H, (bpf_int32)vlan_num, 0x0FFF); gen_and(b0, b1); b0 = b1; } return (b0); } struct block * gen_sample(int rate) { struct block *b0; long long threshold = 0x100000000LL; /* 0xffffffff + 1 */ if (rate < 2) { bpf_error("sample %d is too low", rate); /*NOTREACHED*/ } if (rate > (1 << 20)) { bpf_error("sample %d is too high", rate); /*NOTREACHED*/ } threshold /= rate; b0 = gen_relation(BPF_JGT, gen_loadrnd(), gen_loadi(threshold), 1); return (b0); } struct block * gen_p80211_fcdir(int fcdir) { struct block *b0; u_int offset; if (!(linktype == DLT_IEEE802_11 || linktype == DLT_IEEE802_11_RADIO)) { bpf_error("frame direction not supported on linktype 0x%x", linktype); /* NOTREACHED */ } offset = (u_int)offsetof(struct ieee80211_frame, i_fc[1]); if (linktype == DLT_IEEE802_11_RADIO) offset += IEEE80211_RADIOTAP_HDRLEN; b0 = gen_mcmp(offset, BPF_B, (bpf_int32)fcdir, (bpf_u_int32)IEEE80211_FC1_DIR_MASK); return (b0); } static struct block * gen_p80211_hostop(const u_char *lladdr, int dir) { struct block *b0, *b1, *b2, *b3, *b4; u_int offset = 0; if (linktype == DLT_IEEE802_11_RADIO) offset = IEEE80211_RADIOTAP_HDRLEN; switch (dir) { case Q_SRC: b0 = gen_p80211_addr(IEEE80211_FC1_DIR_NODS, offset + (u_int)offsetof(struct ieee80211_frame, i_addr2), lladdr); b1 = gen_p80211_addr(IEEE80211_FC1_DIR_TODS, offset + (u_int)offsetof(struct ieee80211_frame, i_addr2), lladdr); b2 = gen_p80211_addr(IEEE80211_FC1_DIR_FROMDS, offset + (u_int)offsetof(struct ieee80211_frame, i_addr3), lladdr); b3 = gen_p80211_addr(IEEE80211_FC1_DIR_DSTODS, offset + (u_int)offsetof(struct ieee80211_frame_addr4, i_addr4), lladdr); b4 = gen_p80211_addr(IEEE80211_FC1_DIR_DSTODS, offset + (u_int)offsetof(struct ieee80211_frame_addr4, i_addr2), lladdr); gen_or(b0, b1); gen_or(b1, b2); gen_or(b2, b3); gen_or(b3, b4); return (b4); case Q_DST: b0 = gen_p80211_addr(IEEE80211_FC1_DIR_NODS, offset + (u_int)offsetof(struct ieee80211_frame, i_addr1), lladdr); b1 = gen_p80211_addr(IEEE80211_FC1_DIR_TODS, offset + (u_int)offsetof(struct ieee80211_frame, i_addr3), lladdr); b2 = gen_p80211_addr(IEEE80211_FC1_DIR_FROMDS, offset + (u_int)offsetof(struct ieee80211_frame, i_addr1), lladdr); b3 = gen_p80211_addr(IEEE80211_FC1_DIR_DSTODS, offset + (u_int)offsetof(struct ieee80211_frame_addr4, i_addr3), lladdr); b4 = gen_p80211_addr(IEEE80211_FC1_DIR_DSTODS, offset + (u_int)offsetof(struct ieee80211_frame_addr4, i_addr1), lladdr); gen_or(b0, b1); gen_or(b1, b2); gen_or(b2, b3); gen_or(b3, b4); return (b4); case Q_ADDR1: return (gen_bcmp(offset + (u_int)offsetof(struct ieee80211_frame, i_addr1), IEEE80211_ADDR_LEN, lladdr)); case Q_ADDR2: return (gen_bcmp(offset + (u_int)offsetof(struct ieee80211_frame, i_addr2), IEEE80211_ADDR_LEN, lladdr)); case Q_ADDR3: return (gen_bcmp(offset + (u_int)offsetof(struct ieee80211_frame, i_addr3), IEEE80211_ADDR_LEN, lladdr)); case Q_ADDR4: return (gen_p80211_addr(IEEE80211_FC1_DIR_DSTODS, offset + (u_int)offsetof(struct ieee80211_frame_addr4, i_addr4), lladdr)); case Q_AND: b0 = gen_p80211_hostop(lladdr, Q_SRC); b1 = gen_p80211_hostop(lladdr, Q_DST); gen_and(b0, b1); return (b1); case Q_DEFAULT: case Q_OR: b0 = gen_p80211_hostop(lladdr, Q_ADDR1); b1 = gen_p80211_hostop(lladdr, Q_ADDR2); b2 = gen_p80211_hostop(lladdr, Q_ADDR3); b3 = gen_p80211_hostop(lladdr, Q_ADDR4); gen_or(b0, b1); gen_or(b1, b2); gen_or(b2, b3); return (b3); default: bpf_error("direction not supported on linktype 0x%x", linktype); } /* NOTREACHED */ } static struct block * gen_p80211_addr(int fcdir, u_int offset, const u_char *lladdr) { struct block *b0, *b1; b0 = gen_mcmp(offset, BPF_B, (bpf_int32)fcdir, IEEE80211_FC1_DIR_MASK); b1 = gen_bcmp(offset, IEEE80211_ADDR_LEN, lladdr); gen_and(b0, b1); return (b1); }