1 /* $OpenBSD: filter.c,v 1.9 2009/09/01 13:46:14 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 *, int); 43 int prepare_rule(u_int32_t, int, 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_pooladdr pfp; 51 static struct pfioc_rule pfr; 52 static struct pfioc_trans pft; 53 static struct pfioc_trans_e pfte; 54 static int dev, rule_log; 55 static char *qname, *tagname; 56 57 int 58 add_addr(struct sockaddr *addr, int which) 59 { 60 if (addr->sa_family == AF_INET) { 61 memcpy(&pfp.addr.addr.v.a.addr.v4, 62 &satosin(addr)->sin_addr.s_addr, 4); 63 memset(&pfp.addr.addr.v.a.mask.addr8, 255, 4); 64 } else { 65 memcpy(&pfp.addr.addr.v.a.addr.v6, 66 &satosin6(addr)->sin6_addr.s6_addr, 16); 67 memset(&pfp.addr.addr.v.a.mask.addr8, 255, 16); 68 } 69 pfp.which = which; 70 if (ioctl(dev, DIOCADDADDR, &pfp) == -1) 71 return (-1); 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_FILTER, src, dst, d_port) == -1) 87 return (-1); 88 89 if (add_addr(nat, PF_NAT) == -1) 90 return (-1); 91 92 pfr.rule.direction = PF_OUT; 93 pfr.rule.nat.proxy_port[0] = nat_range_low; 94 pfr.rule.nat.proxy_port[1] = nat_range_high; 95 if (ioctl(dev, DIOCADDRULE, &pfr) == -1) 96 return (-1); 97 98 return (0); 99 } 100 101 int 102 add_rdr(u_int32_t id, struct sockaddr *src, struct sockaddr *dst, 103 u_int16_t d_port, struct sockaddr *rdr, u_int16_t rdr_port) 104 { 105 if (!src || !dst || !d_port || !rdr || !rdr_port || 106 (src->sa_family != rdr->sa_family)) { 107 errno = EINVAL; 108 return (-1); 109 } 110 111 if (prepare_rule(id, PF_RULESET_FILTER, src, dst, d_port) == -1) 112 return (-1); 113 114 if (add_addr(rdr, PF_RDR) == -1) 115 return (-1); 116 117 pfr.rule.direction = PF_IN; 118 pfr.rule.rdr.proxy_port[0] = rdr_port; 119 if (ioctl(dev, DIOCADDRULE, &pfr) == -1) 120 return (-1); 121 122 return (0); 123 } 124 125 int 126 do_commit(void) 127 { 128 if (ioctl(dev, DIOCXCOMMIT, &pft) == -1) 129 return (-1); 130 131 return (0); 132 } 133 134 int 135 do_rollback(void) 136 { 137 if (ioctl(dev, DIOCXROLLBACK, &pft) == -1) 138 return (-1); 139 140 return (0); 141 } 142 143 void 144 init_filter(char *opt_qname, char *opt_tagname, int opt_verbose) 145 { 146 struct pf_status status; 147 148 qname = opt_qname; 149 tagname = opt_tagname; 150 151 if (opt_verbose == 1) 152 rule_log = PF_LOG; 153 else if (opt_verbose == 2) 154 rule_log = PF_LOG_ALL; 155 156 dev = open("/dev/pf", O_RDWR); 157 if (dev == -1) 158 err(1, "open /dev/pf"); 159 if (ioctl(dev, DIOCGETSTATUS, &status) == -1) 160 err(1, "DIOCGETSTATUS"); 161 if (!status.running) 162 errx(1, "pf is disabled"); 163 } 164 165 int 166 prepare_commit(u_int32_t id) 167 { 168 char an[PF_ANCHOR_NAME_SIZE]; 169 170 memset(&pft, 0, sizeof pft); 171 pft.size = 1; 172 pft.esize = sizeof pfte; 173 pft.array = &pfte; 174 175 snprintf(an, PF_ANCHOR_NAME_SIZE, "%s/%d.%d", FTP_PROXY_ANCHOR, 176 getpid(), id); 177 memset(&pfte, 0, sizeof pfte); 178 strlcpy(pfte.anchor, an, PF_ANCHOR_NAME_SIZE); 179 pfte.rs_num = PF_RULESET_FILTER; 180 181 if (ioctl(dev, DIOCXBEGIN, &pft) == -1) 182 return (-1); 183 184 return (0); 185 } 186 187 int 188 prepare_rule(u_int32_t id, int rs_num, struct sockaddr *src, 189 struct sockaddr *dst, u_int16_t d_port) 190 { 191 char an[PF_ANCHOR_NAME_SIZE]; 192 193 if ((src->sa_family != AF_INET && src->sa_family != AF_INET6) || 194 (src->sa_family != dst->sa_family)) { 195 errno = EPROTONOSUPPORT; 196 return (-1); 197 } 198 199 memset(&pfp, 0, sizeof pfp); 200 memset(&pfr, 0, sizeof pfr); 201 snprintf(an, PF_ANCHOR_NAME_SIZE, "%s/%d.%d", FTP_PROXY_ANCHOR, 202 getpid(), id); 203 strlcpy(pfp.anchor, an, PF_ANCHOR_NAME_SIZE); 204 strlcpy(pfr.anchor, an, PF_ANCHOR_NAME_SIZE); 205 206 pfr.ticket = pfte.ticket; 207 if (ioctl(dev, DIOCBEGINADDRS, &pfp) == -1) 208 return (-1); 209 pfr.pool_ticket = pfp.ticket; 210 211 /* Generic for all rule types. */ 212 pfr.rule.af = src->sa_family; 213 pfr.rule.proto = IPPROTO_TCP; 214 pfr.rule.src.addr.type = PF_ADDR_ADDRMASK; 215 pfr.rule.dst.addr.type = PF_ADDR_ADDRMASK; 216 if (src->sa_family == AF_INET) { 217 memcpy(&pfr.rule.src.addr.v.a.addr.v4, 218 &satosin(src)->sin_addr.s_addr, 4); 219 memset(&pfr.rule.src.addr.v.a.mask.addr8, 255, 4); 220 memcpy(&pfr.rule.dst.addr.v.a.addr.v4, 221 &satosin(dst)->sin_addr.s_addr, 4); 222 memset(&pfr.rule.dst.addr.v.a.mask.addr8, 255, 4); 223 } else { 224 memcpy(&pfr.rule.src.addr.v.a.addr.v6, 225 &satosin6(src)->sin6_addr.s6_addr, 16); 226 memset(&pfr.rule.src.addr.v.a.mask.addr8, 255, 16); 227 memcpy(&pfr.rule.dst.addr.v.a.addr.v6, 228 &satosin6(dst)->sin6_addr.s6_addr, 16); 229 memset(&pfr.rule.dst.addr.v.a.mask.addr8, 255, 16); 230 } 231 pfr.rule.dst.port_op = PF_OP_EQ; 232 pfr.rule.dst.port[0] = htons(d_port); 233 234 /* 235 * pass [quick] [log] inet[6] proto tcp \ 236 * from $src to $dst port = $d_port flags S/SA keep state 237 * (max 1) [queue qname] [tag tagname] 238 */ 239 pfr.rule.action = PF_PASS; 240 pfr.rule.quick = 1; 241 pfr.rule.log = rule_log; 242 pfr.rule.keep_state = 1; 243 pfr.rule.flags = TH_SYN; 244 pfr.rule.flagset = (TH_SYN|TH_ACK); 245 pfr.rule.max_states = 1; 246 if (qname != NULL) 247 strlcpy(pfr.rule.qname, qname, sizeof pfr.rule.qname); 248 if (tagname != NULL) { 249 pfr.rule.quick = 0; 250 strlcpy(pfr.rule.tagname, tagname, 251 sizeof pfr.rule.tagname); 252 } 253 254 return (0); 255 } 256 257 int 258 server_lookup(struct sockaddr *client, struct sockaddr *proxy, 259 struct sockaddr *server) 260 { 261 if (client->sa_family == AF_INET) 262 return (server_lookup4(satosin(client), satosin(proxy), 263 satosin(server))); 264 265 if (client->sa_family == AF_INET6) 266 return (server_lookup6(satosin6(client), satosin6(proxy), 267 satosin6(server))); 268 269 errno = EPROTONOSUPPORT; 270 return (-1); 271 } 272 273 int 274 server_lookup4(struct sockaddr_in *client, struct sockaddr_in *proxy, 275 struct sockaddr_in *server) 276 { 277 struct pfioc_natlook pnl; 278 279 memset(&pnl, 0, sizeof pnl); 280 pnl.direction = PF_OUT; 281 pnl.af = AF_INET; 282 pnl.proto = IPPROTO_TCP; 283 memcpy(&pnl.saddr.v4, &client->sin_addr.s_addr, sizeof pnl.saddr.v4); 284 memcpy(&pnl.daddr.v4, &proxy->sin_addr.s_addr, sizeof pnl.daddr.v4); 285 pnl.sport = client->sin_port; 286 pnl.dport = proxy->sin_port; 287 288 if (ioctl(dev, DIOCNATLOOK, &pnl) == -1) 289 return (-1); 290 291 memset(server, 0, sizeof(struct sockaddr_in)); 292 server->sin_len = sizeof(struct sockaddr_in); 293 server->sin_family = AF_INET; 294 memcpy(&server->sin_addr.s_addr, &pnl.rdaddr.v4, 295 sizeof server->sin_addr.s_addr); 296 server->sin_port = pnl.rdport; 297 298 return (0); 299 } 300 301 int 302 server_lookup6(struct sockaddr_in6 *client, struct sockaddr_in6 *proxy, 303 struct sockaddr_in6 *server) 304 { 305 struct pfioc_natlook pnl; 306 307 memset(&pnl, 0, sizeof pnl); 308 pnl.direction = PF_OUT; 309 pnl.af = AF_INET6; 310 pnl.proto = IPPROTO_TCP; 311 memcpy(&pnl.saddr.v6, &client->sin6_addr.s6_addr, sizeof pnl.saddr.v6); 312 memcpy(&pnl.daddr.v6, &proxy->sin6_addr.s6_addr, sizeof pnl.daddr.v6); 313 pnl.sport = client->sin6_port; 314 pnl.dport = proxy->sin6_port; 315 316 if (ioctl(dev, DIOCNATLOOK, &pnl) == -1) 317 return (-1); 318 319 memset(server, 0, sizeof(struct sockaddr_in6)); 320 server->sin6_len = sizeof(struct sockaddr_in6); 321 server->sin6_family = AF_INET6; 322 memcpy(&server->sin6_addr.s6_addr, &pnl.rdaddr.v6, 323 sizeof server->sin6_addr); 324 server->sin6_port = pnl.rdport; 325 326 return (0); 327 } 328