1 /* $OpenBSD: filter.c,v 1.13 2010/01/13 01:07:34 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 42 int add_addr(struct sockaddr *, struct pf_pool *); 43 int prepare_rule(u_int32_t, struct sockaddr *, struct sockaddr *, 44 u_int16_t); 45 int server_lookup4(struct sockaddr_in *, struct sockaddr_in *, 46 struct sockaddr_in *); 47 int server_lookup6(struct sockaddr_in6 *, struct sockaddr_in6 *, 48 struct sockaddr_in6 *); 49 50 static struct pfioc_rule pfr; 51 static struct pfioc_trans pft; 52 static struct pfioc_trans_e pfte; 53 static int dev, rule_log; 54 static char *qname, *tagname; 55 56 int 57 add_addr(struct sockaddr *addr, struct pf_pool *pfp) 58 { 59 if (addr->sa_family == AF_INET) { 60 memcpy(&pfp->addr.v.a.addr.v4, 61 &satosin(addr)->sin_addr.s_addr, 4); 62 memset(&pfp->addr.v.a.mask.addr8, 255, 4); 63 } else { 64 memcpy(&pfp->addr.v.a.addr.v6, 65 &satosin6(addr)->sin6_addr.s6_addr, 16); 66 memset(&pfp->addr.v.a.mask.addr8, 255, 16); 67 } 68 pfp->addr.type = PF_ADDR_ADDRMASK; 69 return (0); 70 } 71 72 int 73 add_nat(u_int32_t id, struct sockaddr *src, struct sockaddr *dst, 74 u_int16_t d_port, struct sockaddr *nat, u_int16_t nat_range_low, 75 u_int16_t nat_range_high) 76 { 77 if (!src || !dst || !d_port || !nat || !nat_range_low || 78 (src->sa_family != nat->sa_family)) { 79 errno = EINVAL; 80 return (-1); 81 } 82 83 if (prepare_rule(id, src, dst, d_port) == -1) 84 return (-1); 85 86 if (add_addr(nat, &pfr.rule.nat) == -1) 87 return (-1); 88 89 pfr.rule.direction = PF_OUT; 90 pfr.rule.nat.proxy_port[0] = nat_range_low; 91 pfr.rule.nat.proxy_port[1] = nat_range_high; 92 if (ioctl(dev, DIOCADDRULE, &pfr) == -1) 93 return (-1); 94 95 return (0); 96 } 97 98 int 99 add_rdr(u_int32_t id, struct sockaddr *src, struct sockaddr *dst, 100 u_int16_t d_port, struct sockaddr *rdr, u_int16_t rdr_port) 101 { 102 if (!src || !dst || !d_port || !rdr || !rdr_port || 103 (src->sa_family != rdr->sa_family)) { 104 errno = EINVAL; 105 return (-1); 106 } 107 108 if (prepare_rule(id, src, dst, d_port) == -1) 109 return (-1); 110 111 if (add_addr(rdr, &pfr.rule.rdr) == -1) 112 return (-1); 113 114 pfr.rule.direction = PF_IN; 115 pfr.rule.rdr.proxy_port[0] = rdr_port; 116 if (ioctl(dev, DIOCADDRULE, &pfr) == -1) 117 return (-1); 118 119 return (0); 120 } 121 122 int 123 do_commit(void) 124 { 125 if (ioctl(dev, DIOCXCOMMIT, &pft) == -1) 126 return (-1); 127 128 return (0); 129 } 130 131 int 132 do_rollback(void) 133 { 134 if (ioctl(dev, DIOCXROLLBACK, &pft) == -1) 135 return (-1); 136 137 return (0); 138 } 139 140 void 141 init_filter(char *opt_qname, char *opt_tagname, int opt_verbose) 142 { 143 struct pf_status status; 144 145 qname = opt_qname; 146 tagname = opt_tagname; 147 148 if (opt_verbose == 1) 149 rule_log = PF_LOG; 150 else if (opt_verbose == 2) 151 rule_log = PF_LOG_ALL; 152 153 dev = open("/dev/pf", O_RDWR); 154 if (dev == -1) 155 err(1, "open /dev/pf"); 156 if (ioctl(dev, DIOCGETSTATUS, &status) == -1) 157 err(1, "DIOCGETSTATUS"); 158 if (!status.running) 159 errx(1, "pf is disabled"); 160 } 161 162 int 163 prepare_commit(u_int32_t id) 164 { 165 char an[PF_ANCHOR_NAME_SIZE]; 166 167 memset(&pft, 0, sizeof pft); 168 pft.size = 1; 169 pft.esize = sizeof pfte; 170 pft.array = &pfte; 171 172 snprintf(an, PF_ANCHOR_NAME_SIZE, "%s/%d.%d", FTP_PROXY_ANCHOR, 173 getpid(), id); 174 memset(&pfte, 0, sizeof pfte); 175 strlcpy(pfte.anchor, an, PF_ANCHOR_NAME_SIZE); 176 pfte.type = PF_TRANS_RULESET; 177 178 if (ioctl(dev, DIOCXBEGIN, &pft) == -1) 179 return (-1); 180 181 return (0); 182 } 183 184 int 185 prepare_rule(u_int32_t id, struct sockaddr *src, 186 struct sockaddr *dst, u_int16_t d_port) 187 { 188 char an[PF_ANCHOR_NAME_SIZE]; 189 190 if ((src->sa_family != AF_INET && src->sa_family != AF_INET6) || 191 (src->sa_family != dst->sa_family)) { 192 errno = EPROTONOSUPPORT; 193 return (-1); 194 } 195 196 memset(&pfr, 0, sizeof pfr); 197 snprintf(an, PF_ANCHOR_NAME_SIZE, "%s/%d.%d", FTP_PROXY_ANCHOR, 198 getpid(), id); 199 strlcpy(pfr.anchor, an, PF_ANCHOR_NAME_SIZE); 200 201 pfr.ticket = pfte.ticket; 202 203 /* Generic for all rule types. */ 204 pfr.rule.af = src->sa_family; 205 pfr.rule.proto = IPPROTO_TCP; 206 pfr.rule.src.addr.type = PF_ADDR_ADDRMASK; 207 pfr.rule.dst.addr.type = PF_ADDR_ADDRMASK; 208 pfr.rule.nat.addr.type = PF_ADDR_NONE; 209 pfr.rule.rdr.addr.type = PF_ADDR_NONE; 210 211 if (src->sa_family == AF_INET) { 212 memcpy(&pfr.rule.src.addr.v.a.addr.v4, 213 &satosin(src)->sin_addr.s_addr, 4); 214 memset(&pfr.rule.src.addr.v.a.mask.addr8, 255, 4); 215 memcpy(&pfr.rule.dst.addr.v.a.addr.v4, 216 &satosin(dst)->sin_addr.s_addr, 4); 217 memset(&pfr.rule.dst.addr.v.a.mask.addr8, 255, 4); 218 } else { 219 memcpy(&pfr.rule.src.addr.v.a.addr.v6, 220 &satosin6(src)->sin6_addr.s6_addr, 16); 221 memset(&pfr.rule.src.addr.v.a.mask.addr8, 255, 16); 222 memcpy(&pfr.rule.dst.addr.v.a.addr.v6, 223 &satosin6(dst)->sin6_addr.s6_addr, 16); 224 memset(&pfr.rule.dst.addr.v.a.mask.addr8, 255, 16); 225 } 226 pfr.rule.dst.port_op = PF_OP_EQ; 227 pfr.rule.dst.port[0] = htons(d_port); 228 229 /* 230 * pass [quick] [log] inet[6] proto tcp \ 231 * from $src to $dst port = $d_port flags S/SA keep state 232 * (max 1) [queue qname] [tag tagname] 233 */ 234 if (tagname != NULL) 235 pfr.rule.action = PF_MATCH; 236 else 237 pfr.rule.action = PF_PASS; 238 pfr.rule.quick = 1; 239 pfr.rule.log = rule_log; 240 pfr.rule.keep_state = 1; 241 pfr.rule.flags = TH_SYN; 242 pfr.rule.flagset = (TH_SYN|TH_ACK); 243 pfr.rule.max_states = 1; 244 if (qname != NULL) 245 strlcpy(pfr.rule.qname, qname, sizeof pfr.rule.qname); 246 if (tagname != NULL) { 247 pfr.rule.quick = 0; 248 strlcpy(pfr.rule.tagname, tagname, 249 sizeof pfr.rule.tagname); 250 } 251 252 return (0); 253 } 254 255 int 256 server_lookup(struct sockaddr *client, struct sockaddr *proxy, 257 struct sockaddr *server) 258 { 259 if (client->sa_family == AF_INET) 260 return (server_lookup4(satosin(client), satosin(proxy), 261 satosin(server))); 262 263 if (client->sa_family == AF_INET6) 264 return (server_lookup6(satosin6(client), satosin6(proxy), 265 satosin6(server))); 266 267 errno = EPROTONOSUPPORT; 268 return (-1); 269 } 270 271 int 272 server_lookup4(struct sockaddr_in *client, struct sockaddr_in *proxy, 273 struct sockaddr_in *server) 274 { 275 struct pfioc_natlook pnl; 276 277 memset(&pnl, 0, sizeof pnl); 278 pnl.direction = PF_OUT; 279 pnl.af = AF_INET; 280 pnl.proto = IPPROTO_TCP; 281 memcpy(&pnl.saddr.v4, &client->sin_addr.s_addr, sizeof pnl.saddr.v4); 282 memcpy(&pnl.daddr.v4, &proxy->sin_addr.s_addr, sizeof pnl.daddr.v4); 283 pnl.sport = client->sin_port; 284 pnl.dport = proxy->sin_port; 285 286 if (ioctl(dev, DIOCNATLOOK, &pnl) == -1) 287 return (-1); 288 289 memset(server, 0, sizeof(struct sockaddr_in)); 290 server->sin_len = sizeof(struct sockaddr_in); 291 server->sin_family = AF_INET; 292 memcpy(&server->sin_addr.s_addr, &pnl.rdaddr.v4, 293 sizeof server->sin_addr.s_addr); 294 server->sin_port = pnl.rdport; 295 296 return (0); 297 } 298 299 int 300 server_lookup6(struct sockaddr_in6 *client, struct sockaddr_in6 *proxy, 301 struct sockaddr_in6 *server) 302 { 303 struct pfioc_natlook pnl; 304 305 memset(&pnl, 0, sizeof pnl); 306 pnl.direction = PF_OUT; 307 pnl.af = AF_INET6; 308 pnl.proto = IPPROTO_TCP; 309 memcpy(&pnl.saddr.v6, &client->sin6_addr.s6_addr, sizeof pnl.saddr.v6); 310 memcpy(&pnl.daddr.v6, &proxy->sin6_addr.s6_addr, sizeof pnl.daddr.v6); 311 pnl.sport = client->sin6_port; 312 pnl.dport = proxy->sin6_port; 313 314 if (ioctl(dev, DIOCNATLOOK, &pnl) == -1) 315 return (-1); 316 317 memset(server, 0, sizeof(struct sockaddr_in6)); 318 server->sin6_len = sizeof(struct sockaddr_in6); 319 server->sin6_family = AF_INET6; 320 memcpy(&server->sin6_addr.s6_addr, &pnl.rdaddr.v6, 321 sizeof server->sin6_addr); 322 server->sin6_port = pnl.rdport; 323 324 return (0); 325 } 326