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 #define _KERNEL_STRUCTURES 20 #include <sys/ioctl.h> 21 #include <sys/types.h> 22 #include <sys/socket.h> 23 24 #include <net/if.h> 25 #include <net/pf/pfvar.h> 26 #include <netinet/in.h> 27 #include <netinet/tcp.h> 28 #include <arpa/inet.h> 29 30 #include <err.h> 31 #include <errno.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 pfioc_rule pfr; 54 static struct pfioc_trans pft; 55 static struct pfioc_trans_e pfte[TRANS_SIZE]; 56 static int dev, rule_log; 57 static char *qname, *tagname; 58 59 int 60 add_filter(u_int32_t id, u_int8_t dir, struct sockaddr *src, 61 struct sockaddr *dst, u_int16_t d_port) 62 { 63 if (!src || !dst || !d_port) { 64 errno = EINVAL; 65 return (-1); 66 } 67 68 if (prepare_rule(id, PF_RULESET_FILTER, src, dst, d_port) == -1) 69 return (-1); 70 71 pfr.rule.direction = dir; 72 if (ioctl(dev, DIOCADDRULE, &pfr) == -1) 73 return (-1); 74 75 return (0); 76 } 77 78 int 79 add_nat(u_int32_t id, struct sockaddr *src, struct sockaddr *dst, 80 u_int16_t d_port, struct sockaddr *nat, u_int16_t nat_range_low, 81 u_int16_t nat_range_high) 82 { 83 if (!src || !dst || !d_port || !nat || !nat_range_low || 84 (src->sa_family != nat->sa_family)) { 85 errno = EINVAL; 86 return (-1); 87 } 88 89 if (prepare_rule(id, PF_RULESET_NAT, src, dst, d_port) == -1) 90 return (-1); 91 92 if (nat->sa_family == AF_INET) { 93 memcpy(&pfp.addr.addr.v.a.addr.v4, 94 &satosin(nat)->sin_addr.s_addr, 4); 95 memset(&pfp.addr.addr.v.a.mask.addr8, 255, 4); 96 } else { 97 memcpy(&pfp.addr.addr.v.a.addr.v6, 98 &satosin6(nat)->sin6_addr.s6_addr, 16); 99 memset(&pfp.addr.addr.v.a.mask.addr8, 255, 16); 100 } 101 if (ioctl(dev, DIOCADDADDR, &pfp) == -1) 102 return (-1); 103 104 pfr.rule.rpool.proxy_port[0] = nat_range_low; 105 pfr.rule.rpool.proxy_port[1] = nat_range_high; 106 if (ioctl(dev, DIOCADDRULE, &pfr) == -1) 107 return (-1); 108 109 return (0); 110 } 111 112 int 113 add_rdr(u_int32_t id, struct sockaddr *src, struct sockaddr *dst, 114 u_int16_t d_port, struct sockaddr *rdr, u_int16_t rdr_port) 115 { 116 if (!src || !dst || !d_port || !rdr || !rdr_port || 117 (src->sa_family != rdr->sa_family)) { 118 errno = EINVAL; 119 return (-1); 120 } 121 122 if (prepare_rule(id, PF_RULESET_RDR, src, dst, d_port) == -1) 123 return (-1); 124 125 if (rdr->sa_family == AF_INET) { 126 memcpy(&pfp.addr.addr.v.a.addr.v4, 127 &satosin(rdr)->sin_addr.s_addr, 4); 128 memset(&pfp.addr.addr.v.a.mask.addr8, 255, 4); 129 } else { 130 memcpy(&pfp.addr.addr.v.a.addr.v6, 131 &satosin6(rdr)->sin6_addr.s6_addr, 16); 132 memset(&pfp.addr.addr.v.a.mask.addr8, 255, 16); 133 } 134 if (ioctl(dev, DIOCADDADDR, &pfp) == -1) 135 return (-1); 136 137 pfr.rule.rpool.proxy_port[0] = rdr_port; 138 if (ioctl(dev, DIOCADDRULE, &pfr) == -1) 139 return (-1); 140 141 return (0); 142 } 143 144 int 145 do_commit(void) 146 { 147 if (ioctl(dev, DIOCXCOMMIT, &pft) == -1) 148 return (-1); 149 150 return (0); 151 } 152 153 int 154 do_rollback(void) 155 { 156 if (ioctl(dev, DIOCXROLLBACK, &pft) == -1) 157 return (-1); 158 159 return (0); 160 } 161 162 void 163 init_filter(char *opt_qname, char *opt_tagname, int opt_verbose) 164 { 165 struct pf_status status; 166 167 qname = opt_qname; 168 tagname = opt_tagname; 169 170 if (opt_verbose == 1) 171 rule_log = PF_LOG; 172 else if (opt_verbose == 2) 173 rule_log = PF_LOG_ALL; 174 175 dev = open("/dev/pf", O_RDWR); 176 if (dev == -1) 177 err(1, "/dev/pf"); 178 if (ioctl(dev, DIOCGETSTATUS, &status) == -1) 179 err(1, "DIOCGETSTATUS"); 180 if (!status.running) 181 errx(1, "pf is disabled"); 182 } 183 184 int 185 prepare_commit(u_int32_t id) 186 { 187 char an[PF_ANCHOR_NAME_SIZE]; 188 int i; 189 190 memset(&pft, 0, sizeof pft); 191 pft.size = TRANS_SIZE; 192 pft.esize = sizeof pfte[0]; 193 pft.array = pfte; 194 195 snprintf(an, PF_ANCHOR_NAME_SIZE, "%s/%d.%d", FTP_PROXY_ANCHOR, 196 getpid(), id); 197 for (i = 0; i < TRANS_SIZE; i++) { 198 memset(&pfte[i], 0, sizeof pfte[0]); 199 strlcpy(pfte[i].anchor, an, PF_ANCHOR_NAME_SIZE); 200 switch (i) { 201 case TRANS_FILTER: 202 pfte[i].rs_num = PF_RULESET_FILTER; 203 break; 204 case TRANS_NAT: 205 pfte[i].rs_num = PF_RULESET_NAT; 206 break; 207 case TRANS_RDR: 208 pfte[i].rs_num = PF_RULESET_RDR; 209 break; 210 default: 211 errno = EINVAL; 212 return (-1); 213 } 214 } 215 216 if (ioctl(dev, DIOCXBEGIN, &pft) == -1) 217 return (-1); 218 219 return (0); 220 } 221 222 int 223 prepare_rule(u_int32_t id, int rs_num, struct sockaddr *src, 224 struct sockaddr *dst, u_int16_t d_port) 225 { 226 char an[PF_ANCHOR_NAME_SIZE]; 227 228 if ((src->sa_family != AF_INET && src->sa_family != AF_INET6) || 229 (src->sa_family != dst->sa_family)) { 230 errno = EPROTONOSUPPORT; 231 return (-1); 232 } 233 234 memset(&pfp, 0, sizeof pfp); 235 memset(&pfr, 0, sizeof pfr); 236 snprintf(an, PF_ANCHOR_NAME_SIZE, "%s/%d.%d", FTP_PROXY_ANCHOR, 237 getpid(), id); 238 strlcpy(pfp.anchor, an, PF_ANCHOR_NAME_SIZE); 239 strlcpy(pfr.anchor, an, PF_ANCHOR_NAME_SIZE); 240 241 switch (rs_num) { 242 case PF_RULESET_FILTER: 243 pfr.ticket = pfte[TRANS_FILTER].ticket; 244 break; 245 case PF_RULESET_NAT: 246 pfr.ticket = pfte[TRANS_NAT].ticket; 247 break; 248 case PF_RULESET_RDR: 249 pfr.ticket = pfte[TRANS_RDR].ticket; 250 break; 251 default: 252 errno = EINVAL; 253 return (-1); 254 } 255 if (ioctl(dev, DIOCBEGINADDRS, &pfp) == -1) 256 return (-1); 257 pfr.pool_ticket = pfp.ticket; 258 259 /* Generic for all rule types. */ 260 pfr.rule.af = src->sa_family; 261 pfr.rule.proto = IPPROTO_TCP; 262 pfr.rule.src.addr.type = PF_ADDR_ADDRMASK; 263 pfr.rule.dst.addr.type = PF_ADDR_ADDRMASK; 264 if (src->sa_family == AF_INET) { 265 memcpy(&pfr.rule.src.addr.v.a.addr.v4, 266 &satosin(src)->sin_addr.s_addr, 4); 267 memset(&pfr.rule.src.addr.v.a.mask.addr8, 255, 4); 268 memcpy(&pfr.rule.dst.addr.v.a.addr.v4, 269 &satosin(dst)->sin_addr.s_addr, 4); 270 memset(&pfr.rule.dst.addr.v.a.mask.addr8, 255, 4); 271 } else { 272 memcpy(&pfr.rule.src.addr.v.a.addr.v6, 273 &satosin6(src)->sin6_addr.s6_addr, 16); 274 memset(&pfr.rule.src.addr.v.a.mask.addr8, 255, 16); 275 memcpy(&pfr.rule.dst.addr.v.a.addr.v6, 276 &satosin6(dst)->sin6_addr.s6_addr, 16); 277 memset(&pfr.rule.dst.addr.v.a.mask.addr8, 255, 16); 278 } 279 pfr.rule.dst.port_op = PF_OP_EQ; 280 pfr.rule.dst.port[0] = htons(d_port); 281 if (tagname != NULL) 282 strlcpy(pfr.rule.tagname, tagname, sizeof pfr.rule.tagname); 283 284 switch (rs_num) { 285 case PF_RULESET_FILTER: 286 /* 287 * pass quick [log] inet[6] proto tcp \ 288 * from $src to $dst port = $d_port flags S/SA keep state 289 * (max 1) [queue qname] 290 */ 291 pfr.rule.action = PF_PASS; 292 pfr.rule.quick = 1; 293 pfr.rule.log = rule_log; 294 pfr.rule.keep_state = 1; 295 pfr.rule.flags = TH_SYN; 296 pfr.rule.flagset = (TH_SYN|TH_ACK); 297 pfr.rule.max_states = 1; 298 if (qname != NULL) 299 strlcpy(pfr.rule.qname, qname, sizeof pfr.rule.qname); 300 break; 301 case PF_RULESET_NAT: 302 /* 303 * nat inet[6] proto tcp from $src to $dst port $d_port -> $nat 304 */ 305 pfr.rule.action = PF_NAT; 306 break; 307 case PF_RULESET_RDR: 308 /* 309 * rdr inet[6] proto tcp from $src to $dst port $d_port -> $rdr 310 */ 311 pfr.rule.action = PF_RDR; 312 break; 313 default: 314 errno = EINVAL; 315 return (-1); 316 } 317 318 return (0); 319 } 320 321 int 322 server_lookup(struct sockaddr *client, struct sockaddr *proxy, 323 struct sockaddr *server) 324 { 325 if (client->sa_family == AF_INET) 326 return (server_lookup4(satosin(client), satosin(proxy), 327 satosin(server))); 328 329 if (client->sa_family == AF_INET6) 330 return (server_lookup6(satosin6(client), satosin6(proxy), 331 satosin6(server))); 332 333 errno = EPROTONOSUPPORT; 334 return (-1); 335 } 336 337 int 338 server_lookup4(struct sockaddr_in *client, struct sockaddr_in *proxy, 339 struct sockaddr_in *server) 340 { 341 struct pfioc_natlook pnl; 342 343 memset(&pnl, 0, sizeof pnl); 344 pnl.direction = PF_OUT; 345 pnl.af = AF_INET; 346 pnl.proto = IPPROTO_TCP; 347 memcpy(&pnl.saddr.v4, &client->sin_addr.s_addr, sizeof pnl.saddr.v4); 348 memcpy(&pnl.daddr.v4, &proxy->sin_addr.s_addr, sizeof pnl.daddr.v4); 349 pnl.sport = client->sin_port; 350 pnl.dport = proxy->sin_port; 351 352 if (ioctl(dev, DIOCNATLOOK, &pnl) == -1) 353 return (-1); 354 355 memset(server, 0, sizeof(struct sockaddr_in)); 356 server->sin_len = sizeof(struct sockaddr_in); 357 server->sin_family = AF_INET; 358 memcpy(&server->sin_addr.s_addr, &pnl.rdaddr.v4, 359 sizeof server->sin_addr.s_addr); 360 server->sin_port = pnl.rdport; 361 362 return (0); 363 } 364 365 int 366 server_lookup6(struct sockaddr_in6 *client, struct sockaddr_in6 *proxy, 367 struct sockaddr_in6 *server) 368 { 369 struct pfioc_natlook pnl; 370 371 memset(&pnl, 0, sizeof pnl); 372 pnl.direction = PF_OUT; 373 pnl.af = AF_INET6; 374 pnl.proto = IPPROTO_TCP; 375 memcpy(&pnl.saddr.v6, &client->sin6_addr.s6_addr, sizeof pnl.saddr.v6); 376 memcpy(&pnl.daddr.v6, &proxy->sin6_addr.s6_addr, sizeof pnl.daddr.v6); 377 pnl.sport = client->sin6_port; 378 pnl.dport = proxy->sin6_port; 379 380 if (ioctl(dev, DIOCNATLOOK, &pnl) == -1) 381 return (-1); 382 383 memset(server, 0, sizeof(struct sockaddr_in6)); 384 server->sin6_len = sizeof(struct sockaddr_in6); 385 server->sin6_family = AF_INET6; 386 memcpy(&server->sin6_addr.s6_addr, &pnl.rdaddr.v6, 387 sizeof server->sin6_addr); 388 server->sin6_port = pnl.rdport; 389 390 return (0); 391 } 392