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