1 /* $OpenBSD: filter.c,v 1.8 2008/06/13 07:25:26 claudio Exp $ */ 2 3 /* 4 * Copyright (c) 2004, 2005 Camiel Dobbelaar, <cd@sentia.nl> 5 * 6 * Permission to use, copy, modify, and distribute this software for any 7 * purpose with or without fee is hereby granted, provided that the above 8 * copyright notice and this permission notice appear in all copies. 9 * 10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 17 */ 18 19 #include <sys/ioctl.h> 20 #include <sys/types.h> 21 #include <sys/socket.h> 22 23 #include <net/if.h> 24 #include <net/pfvar.h> 25 #include <netinet/in.h> 26 #include <netinet/tcp.h> 27 #include <arpa/inet.h> 28 29 #include <err.h> 30 #include <errno.h> 31 #include <libpfctl.h> 32 #include <fcntl.h> 33 #include <stdio.h> 34 #include <string.h> 35 #include <unistd.h> 36 37 #include "filter.h" 38 39 /* From netinet/in.h, but only _KERNEL_ gets them. */ 40 #define satosin(sa) ((struct sockaddr_in *)(sa)) 41 #define satosin6(sa) ((struct sockaddr_in6 *)(sa)) 42 43 enum { TRANS_FILTER = 0, TRANS_NAT, TRANS_RDR, TRANS_SIZE }; 44 45 int prepare_rule(u_int32_t, int, struct sockaddr *, struct sockaddr *, 46 u_int16_t); 47 int server_lookup4(struct sockaddr_in *, struct sockaddr_in *, 48 struct sockaddr_in *); 49 int server_lookup6(struct sockaddr_in6 *, struct sockaddr_in6 *, 50 struct sockaddr_in6 *); 51 52 static struct pfioc_pooladdr pfp; 53 static struct pfctl_rule pfrule; 54 static char pfanchor[PF_ANCHOR_NAME_SIZE]; 55 static char pfanchor_call[PF_ANCHOR_NAME_SIZE]; 56 static uint32_t pfticket; 57 static uint32_t pfpool_ticket; 58 static struct pfioc_trans pft; 59 static struct pfioc_trans_e pfte[TRANS_SIZE]; 60 static int dev, rule_log; 61 static const char *qname, *tagname; 62 63 int 64 add_filter(u_int32_t id, u_int8_t dir, struct sockaddr *src, 65 struct sockaddr *dst, u_int16_t d_port) 66 { 67 if (!src || !dst || !d_port) { 68 errno = EINVAL; 69 return (-1); 70 } 71 72 if (prepare_rule(id, PF_RULESET_FILTER, src, dst, d_port) == -1) 73 return (-1); 74 75 pfrule.direction = dir; 76 if (pfctl_add_rule(dev, &pfrule, pfanchor, pfanchor_call, 77 pfticket, pfpool_ticket)) 78 return (-1); 79 80 return (0); 81 } 82 83 int 84 add_nat(u_int32_t id, struct sockaddr *src, struct sockaddr *dst, 85 u_int16_t d_port, struct sockaddr *nat, u_int16_t nat_range_low, 86 u_int16_t nat_range_high) 87 { 88 if (!src || !dst || !d_port || !nat || !nat_range_low || 89 (src->sa_family != nat->sa_family)) { 90 errno = EINVAL; 91 return (-1); 92 } 93 94 if (prepare_rule(id, PF_RULESET_NAT, src, dst, d_port) == -1) 95 return (-1); 96 97 if (nat->sa_family == AF_INET) { 98 memcpy(&pfp.addr.addr.v.a.addr.v4, 99 &satosin(nat)->sin_addr.s_addr, 4); 100 memset(&pfp.addr.addr.v.a.mask.addr8, 255, 4); 101 } else { 102 memcpy(&pfp.addr.addr.v.a.addr.v6, 103 &satosin6(nat)->sin6_addr.s6_addr, 16); 104 memset(&pfp.addr.addr.v.a.mask.addr8, 255, 16); 105 } 106 if (ioctl(dev, DIOCADDADDR, &pfp) == -1) 107 return (-1); 108 109 pfrule.rpool.proxy_port[0] = nat_range_low; 110 pfrule.rpool.proxy_port[1] = nat_range_high; 111 if (pfctl_add_rule(dev, &pfrule, pfanchor, pfanchor_call, 112 pfticket, pfpool_ticket)) 113 return (-1); 114 115 return (0); 116 } 117 118 int 119 add_rdr(u_int32_t id, struct sockaddr *src, struct sockaddr *dst, 120 u_int16_t d_port, struct sockaddr *rdr, u_int16_t rdr_port) 121 { 122 if (!src || !dst || !d_port || !rdr || !rdr_port || 123 (src->sa_family != rdr->sa_family)) { 124 errno = EINVAL; 125 return (-1); 126 } 127 128 if (prepare_rule(id, PF_RULESET_RDR, src, dst, d_port) == -1) 129 return (-1); 130 131 if (rdr->sa_family == AF_INET) { 132 memcpy(&pfp.addr.addr.v.a.addr.v4, 133 &satosin(rdr)->sin_addr.s_addr, 4); 134 memset(&pfp.addr.addr.v.a.mask.addr8, 255, 4); 135 } else { 136 memcpy(&pfp.addr.addr.v.a.addr.v6, 137 &satosin6(rdr)->sin6_addr.s6_addr, 16); 138 memset(&pfp.addr.addr.v.a.mask.addr8, 255, 16); 139 } 140 if (ioctl(dev, DIOCADDADDR, &pfp) == -1) 141 return (-1); 142 143 pfrule.rpool.proxy_port[0] = rdr_port; 144 if (pfctl_add_rule(dev, &pfrule, pfanchor, pfanchor_call, 145 pfticket, pfpool_ticket)) 146 return (-1); 147 148 return (0); 149 } 150 151 int 152 do_commit(void) 153 { 154 if (ioctl(dev, DIOCXCOMMIT, &pft) == -1) 155 return (-1); 156 157 return (0); 158 } 159 160 int 161 do_rollback(void) 162 { 163 if (ioctl(dev, DIOCXROLLBACK, &pft) == -1) 164 return (-1); 165 166 return (0); 167 } 168 169 void 170 init_filter(const char *opt_qname, const char *opt_tagname, int opt_verbose) 171 { 172 struct pf_status status; 173 174 qname = opt_qname; 175 tagname = opt_tagname; 176 177 if (opt_verbose == 1) 178 rule_log = PF_LOG; 179 else if (opt_verbose == 2) 180 rule_log = PF_LOG_ALL; 181 182 dev = open("/dev/pf", O_RDWR); 183 if (dev == -1) 184 err(1, "open /dev/pf"); 185 if (ioctl(dev, DIOCGETSTATUS, &status) == -1) 186 err(1, "DIOCGETSTATUS"); 187 if (!status.running) 188 errx(1, "pf is disabled"); 189 } 190 191 int 192 prepare_commit(u_int32_t id) 193 { 194 char an[PF_ANCHOR_NAME_SIZE]; 195 int i; 196 197 memset(&pft, 0, sizeof pft); 198 pft.size = TRANS_SIZE; 199 pft.esize = sizeof pfte[0]; 200 pft.array = pfte; 201 202 snprintf(an, PF_ANCHOR_NAME_SIZE, "%s/%d.%d", FTP_PROXY_ANCHOR, 203 getpid(), id); 204 for (i = 0; i < TRANS_SIZE; i++) { 205 memset(&pfte[i], 0, sizeof pfte[0]); 206 strlcpy(pfte[i].anchor, an, PF_ANCHOR_NAME_SIZE); 207 switch (i) { 208 case TRANS_FILTER: 209 pfte[i].rs_num = PF_RULESET_FILTER; 210 break; 211 case TRANS_NAT: 212 pfte[i].rs_num = PF_RULESET_NAT; 213 break; 214 case TRANS_RDR: 215 pfte[i].rs_num = PF_RULESET_RDR; 216 break; 217 default: 218 errno = EINVAL; 219 return (-1); 220 } 221 } 222 223 if (ioctl(dev, DIOCXBEGIN, &pft) == -1) 224 return (-1); 225 226 return (0); 227 } 228 229 int 230 prepare_rule(u_int32_t id, int rs_num, struct sockaddr *src, 231 struct sockaddr *dst, u_int16_t d_port) 232 { 233 char an[PF_ANCHOR_NAME_SIZE]; 234 235 if ((src->sa_family != AF_INET && src->sa_family != AF_INET6) || 236 (src->sa_family != dst->sa_family)) { 237 errno = EPROTONOSUPPORT; 238 return (-1); 239 } 240 241 memset(&pfp, 0, sizeof pfp); 242 memset(&pfrule, 0, sizeof pfrule); 243 snprintf(an, PF_ANCHOR_NAME_SIZE, "%s/%d.%d", FTP_PROXY_ANCHOR, 244 getpid(), id); 245 strlcpy(pfp.anchor, an, PF_ANCHOR_NAME_SIZE); 246 strlcpy(pfanchor, an, PF_ANCHOR_NAME_SIZE); 247 248 switch (rs_num) { 249 case PF_RULESET_FILTER: 250 pfticket = pfte[TRANS_FILTER].ticket; 251 break; 252 case PF_RULESET_NAT: 253 pfticket = pfte[TRANS_NAT].ticket; 254 break; 255 case PF_RULESET_RDR: 256 pfticket = pfte[TRANS_RDR].ticket; 257 break; 258 default: 259 errno = EINVAL; 260 return (-1); 261 } 262 if (ioctl(dev, DIOCBEGINADDRS, &pfp) == -1) 263 return (-1); 264 pfpool_ticket = pfp.ticket; 265 266 /* Generic for all rule types. */ 267 pfrule.af = src->sa_family; 268 pfrule.proto = IPPROTO_TCP; 269 pfrule.src.addr.type = PF_ADDR_ADDRMASK; 270 pfrule.dst.addr.type = PF_ADDR_ADDRMASK; 271 if (src->sa_family == AF_INET) { 272 memcpy(&pfrule.src.addr.v.a.addr.v4, 273 &satosin(src)->sin_addr.s_addr, 4); 274 memset(&pfrule.src.addr.v.a.mask.addr8, 255, 4); 275 memcpy(&pfrule.dst.addr.v.a.addr.v4, 276 &satosin(dst)->sin_addr.s_addr, 4); 277 memset(&pfrule.dst.addr.v.a.mask.addr8, 255, 4); 278 } else { 279 memcpy(&pfrule.src.addr.v.a.addr.v6, 280 &satosin6(src)->sin6_addr.s6_addr, 16); 281 memset(&pfrule.src.addr.v.a.mask.addr8, 255, 16); 282 memcpy(&pfrule.dst.addr.v.a.addr.v6, 283 &satosin6(dst)->sin6_addr.s6_addr, 16); 284 memset(&pfrule.dst.addr.v.a.mask.addr8, 255, 16); 285 } 286 pfrule.dst.port_op = PF_OP_EQ; 287 pfrule.dst.port[0] = htons(d_port); 288 289 switch (rs_num) { 290 case PF_RULESET_FILTER: 291 /* 292 * pass [quick] [log] inet[6] proto tcp \ 293 * from $src to $dst port = $d_port flags S/SA keep state 294 * (max 1) [queue qname] [tag tagname] 295 */ 296 pfrule.action = PF_PASS; 297 pfrule.quick = 1; 298 pfrule.log = rule_log; 299 pfrule.keep_state = 1; 300 pfrule.flags = TH_SYN; 301 pfrule.flagset = (TH_SYN|TH_ACK); 302 pfrule.max_states = 1; 303 if (qname != NULL) 304 strlcpy(pfrule.qname, qname, sizeof pfrule.qname); 305 if (tagname != NULL) { 306 pfrule.quick = 0; 307 strlcpy(pfrule.tagname, tagname, 308 sizeof pfrule.tagname); 309 } 310 break; 311 case PF_RULESET_NAT: 312 /* 313 * nat inet[6] proto tcp from $src to $dst port $d_port -> $nat 314 */ 315 pfrule.action = PF_NAT; 316 break; 317 case PF_RULESET_RDR: 318 /* 319 * rdr inet[6] proto tcp from $src to $dst port $d_port -> $rdr 320 */ 321 pfrule.action = PF_RDR; 322 break; 323 default: 324 errno = EINVAL; 325 return (-1); 326 } 327 328 return (0); 329 } 330 331 int 332 server_lookup(struct sockaddr *client, struct sockaddr *proxy, 333 struct sockaddr *server) 334 { 335 if (client->sa_family == AF_INET) 336 return (server_lookup4(satosin(client), satosin(proxy), 337 satosin(server))); 338 339 if (client->sa_family == AF_INET6) 340 return (server_lookup6(satosin6(client), satosin6(proxy), 341 satosin6(server))); 342 343 errno = EPROTONOSUPPORT; 344 return (-1); 345 } 346 347 int 348 server_lookup4(struct sockaddr_in *client, struct sockaddr_in *proxy, 349 struct sockaddr_in *server) 350 { 351 struct pfioc_natlook pnl; 352 353 memset(&pnl, 0, sizeof pnl); 354 pnl.direction = PF_OUT; 355 pnl.af = AF_INET; 356 pnl.proto = IPPROTO_TCP; 357 memcpy(&pnl.saddr.v4, &client->sin_addr.s_addr, sizeof pnl.saddr.v4); 358 memcpy(&pnl.daddr.v4, &proxy->sin_addr.s_addr, sizeof pnl.daddr.v4); 359 pnl.sport = client->sin_port; 360 pnl.dport = proxy->sin_port; 361 362 if (ioctl(dev, DIOCNATLOOK, &pnl) == -1) 363 return (-1); 364 365 memset(server, 0, sizeof(struct sockaddr_in)); 366 server->sin_len = sizeof(struct sockaddr_in); 367 server->sin_family = AF_INET; 368 memcpy(&server->sin_addr.s_addr, &pnl.rdaddr.v4, 369 sizeof server->sin_addr.s_addr); 370 server->sin_port = pnl.rdport; 371 372 return (0); 373 } 374 375 int 376 server_lookup6(struct sockaddr_in6 *client, struct sockaddr_in6 *proxy, 377 struct sockaddr_in6 *server) 378 { 379 struct pfioc_natlook pnl; 380 381 memset(&pnl, 0, sizeof pnl); 382 pnl.direction = PF_OUT; 383 pnl.af = AF_INET6; 384 pnl.proto = IPPROTO_TCP; 385 memcpy(&pnl.saddr.v6, &client->sin6_addr.s6_addr, sizeof pnl.saddr.v6); 386 memcpy(&pnl.daddr.v6, &proxy->sin6_addr.s6_addr, sizeof pnl.daddr.v6); 387 pnl.sport = client->sin6_port; 388 pnl.dport = proxy->sin6_port; 389 390 if (ioctl(dev, DIOCNATLOOK, &pnl) == -1) 391 return (-1); 392 393 memset(server, 0, sizeof(struct sockaddr_in6)); 394 server->sin6_len = sizeof(struct sockaddr_in6); 395 server->sin6_family = AF_INET6; 396 memcpy(&server->sin6_addr.s6_addr, &pnl.rdaddr.v6, 397 sizeof server->sin6_addr); 398 server->sin6_port = pnl.rdport; 399 400 return (0); 401 } 402