1 /* $OpenBSD: filter.c,v 1.20 2012/09/18 10:11:53 henning 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 46 static struct pfioc_rule pfr; 47 static struct pfioc_trans pft; 48 static struct pfioc_trans_e pfte; 49 static int dev, rule_log; 50 static char *qname, *tagname; 51 52 int 53 add_addr(struct sockaddr *addr, struct pf_pool *pfp) 54 { 55 if (addr->sa_family == AF_INET) { 56 memcpy(&pfp->addr.v.a.addr.v4, 57 &satosin(addr)->sin_addr.s_addr, 4); 58 memset(&pfp->addr.v.a.mask.addr8, 255, 4); 59 } else { 60 memcpy(&pfp->addr.v.a.addr.v6, 61 &satosin6(addr)->sin6_addr.s6_addr, 16); 62 memset(&pfp->addr.v.a.mask.addr8, 255, 16); 63 } 64 pfp->addr.type = PF_ADDR_ADDRMASK; 65 return (0); 66 } 67 68 int 69 add_nat(u_int32_t id, struct sockaddr *src, int s_rd, struct sockaddr *dst, 70 u_int16_t d_port, struct sockaddr *nat, u_int16_t nat_range_low, 71 u_int16_t nat_range_high) 72 { 73 if (!src || !dst || !d_port || !nat || !nat_range_low || 74 !nat_range_high || (src->sa_family != nat->sa_family)) { 75 errno = EINVAL; 76 return (-1); 77 } 78 79 if (prepare_rule(id, src, dst, d_port) == -1) 80 return (-1); 81 82 if (add_addr(nat, &pfr.rule.nat) == -1) 83 return (-1); 84 85 pfr.rule.direction = PF_OUT; 86 pfr.rule.onrdomain = s_rd; 87 pfr.rule.rtableid = -1; 88 pfr.rule.nat.proxy_port[0] = nat_range_low; 89 pfr.rule.nat.proxy_port[1] = nat_range_high; 90 if (ioctl(dev, DIOCADDRULE, &pfr) == -1) 91 return (-1); 92 93 return (0); 94 } 95 96 int 97 add_rdr(u_int32_t id, struct sockaddr *src, int s_rd, struct sockaddr *dst, 98 u_int16_t d_port, struct sockaddr *rdr, u_int16_t rdr_port, int d_rd) 99 { 100 if (!src || !dst || !d_port || !rdr || !rdr_port || 101 (src->sa_family != rdr->sa_family)) { 102 errno = EINVAL; 103 return (-1); 104 } 105 106 if (prepare_rule(id, src, dst, d_port) == -1) 107 return (-1); 108 109 if (add_addr(rdr, &pfr.rule.rdr) == -1) 110 return (-1); 111 112 pfr.rule.direction = PF_IN; 113 pfr.rule.onrdomain = s_rd; 114 pfr.rule.rtableid = d_rd; 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