1 /* $OpenBSD: filter.c,v 1.6 2007/08/01 09:31:41 henning 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/pf/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 <fcntl.h> 32 #include <stdio.h> 33 #include <string.h> 34 #include <unistd.h> 35 36 #include "filter.h" 37 38 /* From netinet/in.h, but only _KERNEL_ gets them. */ 39 #define satosin(sa) ((struct sockaddr_in *)(sa)) 40 #define satosin6(sa) ((struct sockaddr_in6 *)(sa)) 41 42 enum { TRANS_FILTER = 0, TRANS_NAT, TRANS_RDR, TRANS_SIZE }; 43 44 int prepare_rule(u_int32_t, int, struct sockaddr *, struct sockaddr *, 45 u_int16_t); 46 int server_lookup4(struct sockaddr_in *, struct sockaddr_in *, 47 struct sockaddr_in *); 48 int server_lookup6(struct sockaddr_in6 *, struct sockaddr_in6 *, 49 struct sockaddr_in6 *); 50 51 static struct pfioc_pooladdr pfp; 52 static struct pfioc_rule pfr; 53 static struct pfioc_trans pft; 54 static struct pfioc_trans_e pfte[TRANS_SIZE]; 55 static int dev, rule_log; 56 static char *qname, *tagname; 57 58 int 59 add_filter(u_int32_t id, u_int8_t dir, struct sockaddr *src, 60 struct sockaddr *dst, u_int16_t d_port) 61 { 62 if (!src || !dst || !d_port) { 63 errno = EINVAL; 64 return (-1); 65 } 66 67 if (prepare_rule(id, PF_RULESET_FILTER, src, dst, d_port) == -1) 68 return (-1); 69 70 pfr.rule.direction = dir; 71 if (ioctl(dev, DIOCADDRULE, &pfr) == -1) 72 return (-1); 73 74 return (0); 75 } 76 77 int 78 add_nat(u_int32_t id, struct sockaddr *src, struct sockaddr *dst, 79 u_int16_t d_port, struct sockaddr *nat, u_int16_t nat_range_low, 80 u_int16_t nat_range_high) 81 { 82 if (!src || !dst || !d_port || !nat || !nat_range_low || 83 (src->sa_family != nat->sa_family)) { 84 errno = EINVAL; 85 return (-1); 86 } 87 88 if (prepare_rule(id, PF_RULESET_NAT, src, dst, d_port) == -1) 89 return (-1); 90 91 if (nat->sa_family == AF_INET) { 92 memcpy(&pfp.addr.addr.v.a.addr.v4, 93 &satosin(nat)->sin_addr.s_addr, 4); 94 memset(&pfp.addr.addr.v.a.mask.addr8, 255, 4); 95 } else { 96 memcpy(&pfp.addr.addr.v.a.addr.v6, 97 &satosin6(nat)->sin6_addr.s6_addr, 16); 98 memset(&pfp.addr.addr.v.a.mask.addr8, 255, 16); 99 } 100 if (ioctl(dev, DIOCADDADDR, &pfp) == -1) 101 return (-1); 102 103 pfr.rule.rpool.proxy_port[0] = nat_range_low; 104 pfr.rule.rpool.proxy_port[1] = nat_range_high; 105 if (ioctl(dev, DIOCADDRULE, &pfr) == -1) 106 return (-1); 107 108 return (0); 109 } 110 111 int 112 add_rdr(u_int32_t id, struct sockaddr *src, struct sockaddr *dst, 113 u_int16_t d_port, struct sockaddr *rdr, u_int16_t rdr_port) 114 { 115 if (!src || !dst || !d_port || !rdr || !rdr_port || 116 (src->sa_family != rdr->sa_family)) { 117 errno = EINVAL; 118 return (-1); 119 } 120 121 if (prepare_rule(id, PF_RULESET_RDR, src, dst, d_port) == -1) 122 return (-1); 123 124 if (rdr->sa_family == AF_INET) { 125 memcpy(&pfp.addr.addr.v.a.addr.v4, 126 &satosin(rdr)->sin_addr.s_addr, 4); 127 memset(&pfp.addr.addr.v.a.mask.addr8, 255, 4); 128 } else { 129 memcpy(&pfp.addr.addr.v.a.addr.v6, 130 &satosin6(rdr)->sin6_addr.s6_addr, 16); 131 memset(&pfp.addr.addr.v.a.mask.addr8, 255, 16); 132 } 133 if (ioctl(dev, DIOCADDADDR, &pfp) == -1) 134 return (-1); 135 136 pfr.rule.rpool.proxy_port[0] = rdr_port; 137 if (ioctl(dev, DIOCADDRULE, &pfr) == -1) 138 return (-1); 139 140 return (0); 141 } 142 143 int 144 do_commit(void) 145 { 146 if (ioctl(dev, DIOCXCOMMIT, &pft) == -1) 147 return (-1); 148 149 return (0); 150 } 151 152 int 153 do_rollback(void) 154 { 155 if (ioctl(dev, DIOCXROLLBACK, &pft) == -1) 156 return (-1); 157 158 return (0); 159 } 160 161 void 162 init_filter(char *opt_qname, char *opt_tagname, int opt_verbose) 163 { 164 struct pf_status status; 165 166 qname = opt_qname; 167 tagname = opt_tagname; 168 169 if (opt_verbose == 1) 170 rule_log = PF_LOG; 171 else if (opt_verbose == 2) 172 rule_log = PF_LOG_ALL; 173 174 dev = open("/dev/pf", O_RDWR); 175 if (dev == -1) 176 err(1, "/dev/pf"); 177 if (ioctl(dev, DIOCGETSTATUS, &status) == -1) 178 err(1, "DIOCGETSTATUS"); 179 if (!status.running) 180 errx(1, "pf is disabled"); 181 } 182 183 int 184 prepare_commit(u_int32_t id) 185 { 186 char an[PF_ANCHOR_NAME_SIZE]; 187 int i; 188 189 memset(&pft, 0, sizeof pft); 190 pft.size = TRANS_SIZE; 191 pft.esize = sizeof pfte[0]; 192 pft.array = pfte; 193 194 snprintf(an, PF_ANCHOR_NAME_SIZE, "%s/%d.%d", FTP_PROXY_ANCHOR, 195 getpid(), id); 196 for (i = 0; i < TRANS_SIZE; i++) { 197 memset(&pfte[i], 0, sizeof pfte[0]); 198 strlcpy(pfte[i].anchor, an, PF_ANCHOR_NAME_SIZE); 199 switch (i) { 200 case TRANS_FILTER: 201 pfte[i].rs_num = PF_RULESET_FILTER; 202 break; 203 case TRANS_NAT: 204 pfte[i].rs_num = PF_RULESET_NAT; 205 break; 206 case TRANS_RDR: 207 pfte[i].rs_num = PF_RULESET_RDR; 208 break; 209 default: 210 errno = EINVAL; 211 return (-1); 212 } 213 } 214 215 if (ioctl(dev, DIOCXBEGIN, &pft) == -1) 216 return (-1); 217 218 return (0); 219 } 220 221 int 222 prepare_rule(u_int32_t id, int rs_num, struct sockaddr *src, 223 struct sockaddr *dst, u_int16_t d_port) 224 { 225 char an[PF_ANCHOR_NAME_SIZE]; 226 227 if ((src->sa_family != AF_INET && src->sa_family != AF_INET6) || 228 (src->sa_family != dst->sa_family)) { 229 errno = EPROTONOSUPPORT; 230 return (-1); 231 } 232 233 memset(&pfp, 0, sizeof pfp); 234 memset(&pfr, 0, sizeof pfr); 235 snprintf(an, PF_ANCHOR_NAME_SIZE, "%s/%d.%d", FTP_PROXY_ANCHOR, 236 getpid(), id); 237 strlcpy(pfp.anchor, an, PF_ANCHOR_NAME_SIZE); 238 strlcpy(pfr.anchor, an, PF_ANCHOR_NAME_SIZE); 239 240 switch (rs_num) { 241 case PF_RULESET_FILTER: 242 pfr.ticket = pfte[TRANS_FILTER].ticket; 243 break; 244 case PF_RULESET_NAT: 245 pfr.ticket = pfte[TRANS_NAT].ticket; 246 break; 247 case PF_RULESET_RDR: 248 pfr.ticket = pfte[TRANS_RDR].ticket; 249 break; 250 default: 251 errno = EINVAL; 252 return (-1); 253 } 254 if (ioctl(dev, DIOCBEGINADDRS, &pfp) == -1) 255 return (-1); 256 pfr.pool_ticket = pfp.ticket; 257 258 /* Generic for all rule types. */ 259 pfr.rule.af = src->sa_family; 260 pfr.rule.proto = IPPROTO_TCP; 261 pfr.rule.src.addr.type = PF_ADDR_ADDRMASK; 262 pfr.rule.dst.addr.type = PF_ADDR_ADDRMASK; 263 if (src->sa_family == AF_INET) { 264 memcpy(&pfr.rule.src.addr.v.a.addr.v4, 265 &satosin(src)->sin_addr.s_addr, 4); 266 memset(&pfr.rule.src.addr.v.a.mask.addr8, 255, 4); 267 memcpy(&pfr.rule.dst.addr.v.a.addr.v4, 268 &satosin(dst)->sin_addr.s_addr, 4); 269 memset(&pfr.rule.dst.addr.v.a.mask.addr8, 255, 4); 270 } else { 271 memcpy(&pfr.rule.src.addr.v.a.addr.v6, 272 &satosin6(src)->sin6_addr.s6_addr, 16); 273 memset(&pfr.rule.src.addr.v.a.mask.addr8, 255, 16); 274 memcpy(&pfr.rule.dst.addr.v.a.addr.v6, 275 &satosin6(dst)->sin6_addr.s6_addr, 16); 276 memset(&pfr.rule.dst.addr.v.a.mask.addr8, 255, 16); 277 } 278 pfr.rule.dst.port_op = PF_OP_EQ; 279 pfr.rule.dst.port[0] = htons(d_port); 280 if (tagname != NULL) 281 strlcpy(pfr.rule.tagname, tagname, sizeof pfr.rule.tagname); 282 283 switch (rs_num) { 284 case PF_RULESET_FILTER: 285 /* 286 * pass quick [log] inet[6] proto tcp \ 287 * from $src to $dst port = $d_port flags S/SA keep state 288 * (max 1) [queue qname] 289 */ 290 pfr.rule.action = PF_PASS; 291 pfr.rule.quick = 1; 292 pfr.rule.log = rule_log; 293 pfr.rule.keep_state = 1; 294 pfr.rule.flags = TH_SYN; 295 pfr.rule.flagset = (TH_SYN|TH_ACK); 296 pfr.rule.max_states = 1; 297 if (qname != NULL) 298 strlcpy(pfr.rule.qname, qname, sizeof pfr.rule.qname); 299 break; 300 case PF_RULESET_NAT: 301 /* 302 * nat inet[6] proto tcp from $src to $dst port $d_port -> $nat 303 */ 304 pfr.rule.action = PF_NAT; 305 break; 306 case PF_RULESET_RDR: 307 /* 308 * rdr inet[6] proto tcp from $src to $dst port $d_port -> $rdr 309 */ 310 pfr.rule.action = PF_RDR; 311 break; 312 default: 313 errno = EINVAL; 314 return (-1); 315 } 316 317 return (0); 318 } 319 320 int 321 server_lookup(struct sockaddr *client, struct sockaddr *proxy, 322 struct sockaddr *server) 323 { 324 if (client->sa_family == AF_INET) 325 return (server_lookup4(satosin(client), satosin(proxy), 326 satosin(server))); 327 328 if (client->sa_family == AF_INET6) 329 return (server_lookup6(satosin6(client), satosin6(proxy), 330 satosin6(server))); 331 332 errno = EPROTONOSUPPORT; 333 return (-1); 334 } 335 336 int 337 server_lookup4(struct sockaddr_in *client, struct sockaddr_in *proxy, 338 struct sockaddr_in *server) 339 { 340 struct pfioc_natlook pnl; 341 342 memset(&pnl, 0, sizeof pnl); 343 pnl.direction = PF_OUT; 344 pnl.af = AF_INET; 345 pnl.proto = IPPROTO_TCP; 346 memcpy(&pnl.saddr.v4, &client->sin_addr.s_addr, sizeof pnl.saddr.v4); 347 memcpy(&pnl.daddr.v4, &proxy->sin_addr.s_addr, sizeof pnl.daddr.v4); 348 pnl.sport = client->sin_port; 349 pnl.dport = proxy->sin_port; 350 351 if (ioctl(dev, DIOCNATLOOK, &pnl) == -1) 352 return (-1); 353 354 memset(server, 0, sizeof(struct sockaddr_in)); 355 server->sin_len = sizeof(struct sockaddr_in); 356 server->sin_family = AF_INET; 357 memcpy(&server->sin_addr.s_addr, &pnl.rdaddr.v4, 358 sizeof server->sin_addr.s_addr); 359 server->sin_port = pnl.rdport; 360 361 return (0); 362 } 363 364 int 365 server_lookup6(struct sockaddr_in6 *client, struct sockaddr_in6 *proxy, 366 struct sockaddr_in6 *server) 367 { 368 struct pfioc_natlook pnl; 369 370 memset(&pnl, 0, sizeof pnl); 371 pnl.direction = PF_OUT; 372 pnl.af = AF_INET6; 373 pnl.proto = IPPROTO_TCP; 374 memcpy(&pnl.saddr.v6, &client->sin6_addr.s6_addr, sizeof pnl.saddr.v6); 375 memcpy(&pnl.daddr.v6, &proxy->sin6_addr.s6_addr, sizeof pnl.daddr.v6); 376 pnl.sport = client->sin6_port; 377 pnl.dport = proxy->sin6_port; 378 379 if (ioctl(dev, DIOCNATLOOK, &pnl) == -1) 380 return (-1); 381 382 memset(server, 0, sizeof(struct sockaddr_in6)); 383 server->sin6_len = sizeof(struct sockaddr_in6); 384 server->sin6_family = AF_INET6; 385 memcpy(&server->sin6_addr.s6_addr, &pnl.rdaddr.v6, 386 sizeof server->sin6_addr); 387 server->sin6_port = pnl.rdport; 388 389 return (0); 390 } 391