filter.c revision 272461
1124758Semax/* $OpenBSD: filter.c,v 1.8 2008/06/13 07:25:26 claudio Exp $ */ 2124758Semax 3124758Semax/* 4124758Semax * Copyright (c) 2004, 2005 Camiel Dobbelaar, <cd@sentia.nl> 5124758Semax * 6124758Semax * Permission to use, copy, modify, and distribute this software for any 7124758Semax * purpose with or without fee is hereby granted, provided that the above 8124758Semax * copyright notice and this permission notice appear in all copies. 9124758Semax * 10124758Semax * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 11124758Semax * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 12124758Semax * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 13124758Semax * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 14124758Semax * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 15124758Semax * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 16124758Semax * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 17124758Semax */ 18124758Semax 19124758Semax#include <sys/ioctl.h> 20124758Semax#include <sys/types.h> 21124758Semax#include <sys/socket.h> 22124758Semax 23124758Semax#include <net/if.h> 24124758Semax#include <net/pfvar.h> 25124758Semax#include <netinet/in.h> 26124758Semax#include <netinet/tcp.h> 27124758Semax#include <arpa/inet.h> 28124758Semax 29124758Semax#include <err.h> 30124758Semax#include <errno.h> 31124758Semax#include <fcntl.h> 32124758Semax#include <stdio.h> 33124758Semax#include <string.h> 34124758Semax#include <unistd.h> 35124758Semax 36124758Semax#include "filter.h" 37124758Semax 38124758Semax/* From netinet/in.h, but only _KERNEL_ gets them. */ 39124758Semax#define satosin(sa) ((struct sockaddr_in *)(sa)) 40124758Semax#define satosin6(sa) ((struct sockaddr_in6 *)(sa)) 41124758Semax 42124758Semaxenum { TRANS_FILTER = 0, TRANS_NAT, TRANS_RDR, TRANS_SIZE }; 43124758Semax 44124758Semaxint prepare_rule(u_int32_t, int, struct sockaddr *, struct sockaddr *, 45124758Semax u_int16_t); 46124758Semaxint server_lookup4(struct sockaddr_in *, struct sockaddr_in *, 47124758Semax struct sockaddr_in *); 48124758Semaxint server_lookup6(struct sockaddr_in6 *, struct sockaddr_in6 *, 49124758Semax struct sockaddr_in6 *); 50124758Semax 51124758Semaxstatic struct pfioc_pooladdr pfp; 52124758Semaxstatic struct pfioc_rule pfr; 53124758Semaxstatic struct pfioc_trans pft; 54124758Semaxstatic struct pfioc_trans_e pfte[TRANS_SIZE]; 55124758Semaxstatic int dev, rule_log; 56124758Semaxstatic const char *qname, *tagname; 57124758Semax 58124758Semaxint 59124758Semaxadd_filter(u_int32_t id, u_int8_t dir, struct sockaddr *src, 60124758Semax struct sockaddr *dst, u_int16_t d_port) 61124758Semax{ 62124758Semax if (!src || !dst || !d_port) { 63124758Semax errno = EINVAL; 64124758Semax return (-1); 65124758Semax } 66124758Semax 67124758Semax if (prepare_rule(id, PF_RULESET_FILTER, src, dst, d_port) == -1) 68124758Semax return (-1); 69124758Semax 70124758Semax pfr.rule.direction = dir; 71124758Semax if (ioctl(dev, DIOCADDRULE, &pfr) == -1) 72124758Semax return (-1); 73124758Semax 74124758Semax return (0); 75124758Semax} 76124758Semax 77124758Semaxint 78124758Semaxadd_nat(u_int32_t id, struct sockaddr *src, struct sockaddr *dst, 79124758Semax u_int16_t d_port, struct sockaddr *nat, u_int16_t nat_range_low, 80124758Semax u_int16_t nat_range_high) 81124758Semax{ 82124758Semax if (!src || !dst || !d_port || !nat || !nat_range_low || 83124758Semax (src->sa_family != nat->sa_family)) { 84124758Semax errno = EINVAL; 85124758Semax return (-1); 86124758Semax } 87124758Semax 88124758Semax if (prepare_rule(id, PF_RULESET_NAT, src, dst, d_port) == -1) 89124758Semax return (-1); 90124758Semax 91124758Semax if (nat->sa_family == AF_INET) { 92124758Semax memcpy(&pfp.addr.addr.v.a.addr.v4, 93124758Semax &satosin(nat)->sin_addr.s_addr, 4); 94124758Semax memset(&pfp.addr.addr.v.a.mask.addr8, 255, 4); 95124758Semax } else { 96124758Semax memcpy(&pfp.addr.addr.v.a.addr.v6, 97124758Semax &satosin6(nat)->sin6_addr.s6_addr, 16); 98124758Semax memset(&pfp.addr.addr.v.a.mask.addr8, 255, 16); 99124758Semax } 100124758Semax if (ioctl(dev, DIOCADDADDR, &pfp) == -1) 101124758Semax return (-1); 102124758Semax 103124758Semax pfr.rule.rpool.proxy_port[0] = nat_range_low; 104124758Semax pfr.rule.rpool.proxy_port[1] = nat_range_high; 105124758Semax if (ioctl(dev, DIOCADDRULE, &pfr) == -1) 106124758Semax return (-1); 107124758Semax 108124758Semax return (0); 109124758Semax} 110124758Semax 111124758Semaxint 112124758Semaxadd_rdr(u_int32_t id, struct sockaddr *src, struct sockaddr *dst, 113124758Semax u_int16_t d_port, struct sockaddr *rdr, u_int16_t rdr_port) 114124758Semax{ 115124758Semax if (!src || !dst || !d_port || !rdr || !rdr_port || 116124758Semax (src->sa_family != rdr->sa_family)) { 117124758Semax errno = EINVAL; 118124758Semax return (-1); 119124758Semax } 120124758Semax 121124758Semax if (prepare_rule(id, PF_RULESET_RDR, src, dst, d_port) == -1) 122124758Semax return (-1); 123124758Semax 124124758Semax if (rdr->sa_family == AF_INET) { 125124758Semax memcpy(&pfp.addr.addr.v.a.addr.v4, 126124758Semax &satosin(rdr)->sin_addr.s_addr, 4); 127124758Semax memset(&pfp.addr.addr.v.a.mask.addr8, 255, 4); 128124758Semax } else { 129124758Semax memcpy(&pfp.addr.addr.v.a.addr.v6, 130124758Semax &satosin6(rdr)->sin6_addr.s6_addr, 16); 131124758Semax memset(&pfp.addr.addr.v.a.mask.addr8, 255, 16); 132124758Semax } 133124758Semax if (ioctl(dev, DIOCADDADDR, &pfp) == -1) 134124758Semax return (-1); 135124758Semax 136124758Semax pfr.rule.rpool.proxy_port[0] = rdr_port; 137124758Semax if (ioctl(dev, DIOCADDRULE, &pfr) == -1) 138124758Semax return (-1); 139124758Semax 140124758Semax return (0); 141124758Semax} 142124758Semax 143124758Semaxint 144124758Semaxdo_commit(void) 145124758Semax{ 146124758Semax if (ioctl(dev, DIOCXCOMMIT, &pft) == -1) 147124758Semax return (-1); 148124758Semax 149124758Semax return (0); 150124758Semax} 151124758Semax 152124758Semaxint 153124758Semaxdo_rollback(void) 154124758Semax{ 155124758Semax if (ioctl(dev, DIOCXROLLBACK, &pft) == -1) 156124758Semax return (-1); 157124758Semax 158124758Semax return (0); 159124758Semax} 160124758Semax 161124758Semaxvoid 162124758Semaxinit_filter(const char *opt_qname, const char *opt_tagname, int opt_verbose) 163124758Semax{ 164124758Semax struct pf_status status; 165124758Semax 166124758Semax qname = opt_qname; 167124758Semax tagname = opt_tagname; 168124758Semax 169124758Semax if (opt_verbose == 1) 170124758Semax rule_log = PF_LOG; 171124758Semax else if (opt_verbose == 2) 172124758Semax rule_log = PF_LOG_ALL; 173124758Semax 174124758Semax dev = open("/dev/pf", O_RDWR); 175124758Semax if (dev == -1) 176124758Semax err(1, "open /dev/pf"); 177124758Semax if (ioctl(dev, DIOCGETSTATUS, &status) == -1) 178124758Semax err(1, "DIOCGETSTATUS"); 179124758Semax if (!status.running) 180124758Semax errx(1, "pf is disabled"); 181124758Semax} 182124758Semax 183124758Semaxint 184124758Semaxprepare_commit(u_int32_t id) 185124758Semax{ 186124758Semax char an[PF_ANCHOR_NAME_SIZE]; 187124758Semax int i; 188124758Semax 189124758Semax memset(&pft, 0, sizeof pft); 190124758Semax pft.size = TRANS_SIZE; 191124758Semax pft.esize = sizeof pfte[0]; 192124758Semax pft.array = pfte; 193124758Semax 194124758Semax snprintf(an, PF_ANCHOR_NAME_SIZE, "%s/%d.%d", FTP_PROXY_ANCHOR, 195124758Semax getpid(), id); 196124758Semax for (i = 0; i < TRANS_SIZE; i++) { 197124758Semax memset(&pfte[i], 0, sizeof pfte[0]); 198124758Semax strlcpy(pfte[i].anchor, an, PF_ANCHOR_NAME_SIZE); 199124758Semax switch (i) { 200124758Semax case TRANS_FILTER: 201124758Semax pfte[i].rs_num = PF_RULESET_FILTER; 202124758Semax break; 203124758Semax case TRANS_NAT: 204124758Semax pfte[i].rs_num = PF_RULESET_NAT; 205124758Semax break; 206124758Semax case TRANS_RDR: 207124758Semax pfte[i].rs_num = PF_RULESET_RDR; 208124758Semax break; 209124758Semax default: 210124758Semax errno = EINVAL; 211124758Semax return (-1); 212124758Semax } 213124758Semax } 214124758Semax 215124758Semax if (ioctl(dev, DIOCXBEGIN, &pft) == -1) 216124758Semax return (-1); 217124758Semax 218124758Semax return (0); 219124758Semax} 220124758Semax 221124758Semaxint 222124758Semaxprepare_rule(u_int32_t id, int rs_num, struct sockaddr *src, 223124758Semax struct sockaddr *dst, u_int16_t d_port) 224124758Semax{ 225124758Semax char an[PF_ANCHOR_NAME_SIZE]; 226124758Semax 227124758Semax if ((src->sa_family != AF_INET && src->sa_family != AF_INET6) || 228124758Semax (src->sa_family != dst->sa_family)) { 229124758Semax errno = EPROTONOSUPPORT; 230124758Semax return (-1); 231124758Semax } 232124758Semax 233124758Semax memset(&pfp, 0, sizeof pfp); 234124758Semax memset(&pfr, 0, sizeof pfr); 235124758Semax 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); 280 281 switch (rs_num) { 282 case PF_RULESET_FILTER: 283 /* 284 * pass [quick] [log] inet[6] proto tcp \ 285 * from $src to $dst port = $d_port flags S/SA keep state 286 * (max 1) [queue qname] [tag tagname] 287 */ 288 pfr.rule.action = PF_PASS; 289 pfr.rule.quick = 1; 290 pfr.rule.log = rule_log; 291 pfr.rule.keep_state = 1; 292 pfr.rule.flags = TH_SYN; 293 pfr.rule.flagset = (TH_SYN|TH_ACK); 294 pfr.rule.max_states = 1; 295 if (qname != NULL) 296 strlcpy(pfr.rule.qname, qname, sizeof pfr.rule.qname); 297 if (tagname != NULL) { 298 pfr.rule.quick = 0; 299 strlcpy(pfr.rule.tagname, tagname, 300 sizeof pfr.rule.tagname); 301 } 302 break; 303 case PF_RULESET_NAT: 304 /* 305 * nat inet[6] proto tcp from $src to $dst port $d_port -> $nat 306 */ 307 pfr.rule.action = PF_NAT; 308 break; 309 case PF_RULESET_RDR: 310 /* 311 * rdr inet[6] proto tcp from $src to $dst port $d_port -> $rdr 312 */ 313 pfr.rule.action = PF_RDR; 314 break; 315 default: 316 errno = EINVAL; 317 return (-1); 318 } 319 320 return (0); 321} 322 323int 324server_lookup(struct sockaddr *client, struct sockaddr *proxy, 325 struct sockaddr *server) 326{ 327 if (client->sa_family == AF_INET) 328 return (server_lookup4(satosin(client), satosin(proxy), 329 satosin(server))); 330 331 if (client->sa_family == AF_INET6) 332 return (server_lookup6(satosin6(client), satosin6(proxy), 333 satosin6(server))); 334 335 errno = EPROTONOSUPPORT; 336 return (-1); 337} 338 339int 340server_lookup4(struct sockaddr_in *client, struct sockaddr_in *proxy, 341 struct sockaddr_in *server) 342{ 343 struct pfioc_natlook pnl; 344 345 memset(&pnl, 0, sizeof pnl); 346 pnl.direction = PF_OUT; 347 pnl.af = AF_INET; 348 pnl.proto = IPPROTO_TCP; 349 memcpy(&pnl.saddr.v4, &client->sin_addr.s_addr, sizeof pnl.saddr.v4); 350 memcpy(&pnl.daddr.v4, &proxy->sin_addr.s_addr, sizeof pnl.daddr.v4); 351 pnl.sport = client->sin_port; 352 pnl.dport = proxy->sin_port; 353 354 if (ioctl(dev, DIOCNATLOOK, &pnl) == -1) 355 return (-1); 356 357 memset(server, 0, sizeof(struct sockaddr_in)); 358 server->sin_len = sizeof(struct sockaddr_in); 359 server->sin_family = AF_INET; 360 memcpy(&server->sin_addr.s_addr, &pnl.rdaddr.v4, 361 sizeof server->sin_addr.s_addr); 362 server->sin_port = pnl.rdport; 363 364 return (0); 365} 366 367int 368server_lookup6(struct sockaddr_in6 *client, struct sockaddr_in6 *proxy, 369 struct sockaddr_in6 *server) 370{ 371 struct pfioc_natlook pnl; 372 373 memset(&pnl, 0, sizeof pnl); 374 pnl.direction = PF_OUT; 375 pnl.af = AF_INET6; 376 pnl.proto = IPPROTO_TCP; 377 memcpy(&pnl.saddr.v6, &client->sin6_addr.s6_addr, sizeof pnl.saddr.v6); 378 memcpy(&pnl.daddr.v6, &proxy->sin6_addr.s6_addr, sizeof pnl.daddr.v6); 379 pnl.sport = client->sin6_port; 380 pnl.dport = proxy->sin6_port; 381 382 if (ioctl(dev, DIOCNATLOOK, &pnl) == -1) 383 return (-1); 384 385 memset(server, 0, sizeof(struct sockaddr_in6)); 386 server->sin6_len = sizeof(struct sockaddr_in6); 387 server->sin6_family = AF_INET6; 388 memcpy(&server->sin6_addr.s6_addr, &pnl.rdaddr.v6, 389 sizeof server->sin6_addr); 390 server->sin6_port = pnl.rdport; 391 392 return (0); 393} 394