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 <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 42enum { TRANS_FILTER = 0, TRANS_NAT, TRANS_RDR, TRANS_SIZE }; 43 44int prepare_rule(u_int32_t, int, struct sockaddr *, struct sockaddr *, 45 u_int16_t); 46int server_lookup4(struct sockaddr_in *, struct sockaddr_in *, 47 struct sockaddr_in *); 48int server_lookup6(struct sockaddr_in6 *, struct sockaddr_in6 *, 49 struct sockaddr_in6 *); 50 51static struct pfioc_pooladdr pfp; 52static struct pfioc_rule pfr; 53static struct pfioc_trans pft; 54static struct pfioc_trans_e pfte[TRANS_SIZE]; 55static int dev, rule_log; 56static const char *qname, *tagname; 57 58int 59add_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 77int 78add_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 111int 112add_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 143int 144do_commit(void) 145{ 146 if (ioctl(dev, DIOCXCOMMIT, &pft) == -1) 147 return (-1); 148 149 return (0); 150} 151 152int 153do_rollback(void) 154{ 155 if (ioctl(dev, DIOCXROLLBACK, &pft) == -1) 156 return (-1); 157 158 return (0); 159} 160 161void 162init_filter(const char *opt_qname, const 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, "open /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 183int 184prepare_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 221int 222prepare_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); 280 281 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