1 /* $OpenBSD: pf.c,v 1.15 2009/10/27 23:59:52 deraadt Exp $ */ 2 3 /* 4 * Copyright (c) 1993-95 Mats O Jansson. All rights reserved. 5 * Copyright (c) 1990 The Regents of the University of California. 6 * All rights reserved. 7 * 8 * This code is partly derived from rarpd. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 22 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 */ 30 31 #include <stdio.h> 32 #include <unistd.h> 33 #include <sys/types.h> 34 #include <sys/time.h> 35 #include <sys/ioctl.h> 36 #include <sys/file.h> 37 #include <sys/socket.h> 38 #include <sys/uio.h> 39 #include <net/if.h> 40 41 #include <net/bpf.h> 42 43 #include <netinet/in.h> 44 #include <netinet/if_ether.h> 45 46 #include <netdb.h> 47 #include <ctype.h> 48 #include <string.h> 49 #include <err.h> 50 #include <errno.h> 51 52 #include <syslog.h> 53 54 #include "common/mopdef.h" 55 56 /* 57 * Variables 58 */ 59 60 extern int promisc; 61 62 /* 63 * Return information to device.c how to open device. 64 * In this case the driver can handle both Ethernet type II and 65 * IEEE 802.3 frames (SNAP) in a single pfOpen. 66 */ 67 /* ARGSUSED */ 68 int 69 pfTrans(char *interface) 70 { 71 return (TRANS_ETHER + TRANS_8023 + TRANS_AND); 72 } 73 74 /* 75 * Open and initialize packet filter. 76 */ 77 /* ARGSUSED */ 78 int 79 pfInit(char *interface, int mode, u_short protocol, int typ) 80 { 81 int fd; 82 int n = 0; 83 char device[sizeof "/dev/bpf000"]; 84 struct ifreq ifr; 85 u_int dlt; 86 int immediate; 87 88 static struct bpf_insn insns[] = { 89 BPF_STMT(BPF_LD | BPF_H | BPF_ABS, 12), 90 BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, 0x4711, 4, 0), 91 BPF_STMT(BPF_LD | BPF_H | BPF_ABS, 20), 92 BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, 0x4711, 0, 3), 93 BPF_STMT(BPF_LD | BPF_H | BPF_ABS, 14), 94 BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, 0xaaaa, 0, 1), 95 BPF_STMT(BPF_RET | BPF_K, 1520), 96 BPF_STMT(BPF_RET | BPF_K, 0), 97 }; 98 static struct bpf_program filter = { 99 sizeof insns / sizeof(insns[0]), 100 insns 101 }; 102 103 /* Go through all the minors and find one that isn't in use. */ 104 do { 105 snprintf(device, sizeof device, "/dev/bpf%d", n++); 106 fd = open(device, mode); 107 } while (fd < 0 && errno == EBUSY); 108 109 if (fd < 0) { 110 syslog(LOG_ERR,"pfInit: open bpf %m"); 111 return (-1); 112 } 113 114 /* Set immediate mode so packets are processed as they arrive. */ 115 immediate = 1; 116 if (ioctl(fd, BIOCIMMEDIATE, &immediate) < 0) { 117 syslog(LOG_ERR,"pfInit: BIOCIMMEDIATE: %m"); 118 return (-1); 119 } 120 strncpy(ifr.ifr_name, interface, sizeof ifr.ifr_name); 121 if (ioctl(fd, BIOCSETIF, &ifr) < 0) { 122 syslog(LOG_ERR,"pfInit: BIOCSETIF: %m"); 123 return (-1); 124 } 125 /* Check that the data link layer is an Ethernet; this code won't work 126 * with anything else. */ 127 if (ioctl(fd, BIOCGDLT, &dlt) < 0) { 128 syslog(LOG_ERR,"pfInit: BIOCGDLT: %m"); 129 return (-1); 130 } 131 if (dlt != DLT_EN10MB) { 132 syslog(LOG_ERR,"pfInit: %s is not ethernet", device); 133 return (-1); 134 } 135 if (promisc) 136 /* Set promiscuous mode. */ 137 if (ioctl(fd, BIOCPROMISC, 0) < 0) { 138 syslog(LOG_ERR,"pfInit: BIOCPROMISC: %m"); 139 return (-1); 140 } 141 142 /* Set filter program. */ 143 insns[1].k = protocol; 144 insns[3].k = protocol; 145 146 if (ioctl(fd, BIOCSETF, &filter) < 0) { 147 syslog(LOG_ERR,"pfInit: BIOCSETF: %m"); 148 return (-1); 149 } 150 151 /* XXX set the same write filter (for protocol only) */ 152 if (ioctl(fd, BIOCSETWF, &filter) < 0) { 153 syslog(LOG_ERR,"pfInit: BIOCSETWF: %m"); 154 return (-1); 155 } 156 157 /* Lock the interface to prevent further changes */ 158 if (ioctl(fd, BIOCLOCK) < 0) { 159 syslog(LOG_ERR,"pfInit: BIOCLOCK: %m"); 160 return (-1); 161 } 162 163 return (fd); 164 } 165 166 /* 167 * Add a Multicast address to the interface 168 */ 169 /* ARGSUSED */ 170 int 171 pfAddMulti(int s, char *interface, char *addr) 172 { 173 struct ifreq ifr; 174 int fd; 175 176 strncpy(ifr.ifr_name, interface, sizeof(ifr.ifr_name) - 1); 177 ifr.ifr_name[sizeof(ifr.ifr_name) - 1] = 0; 178 179 ifr.ifr_addr.sa_family = AF_UNSPEC; 180 bcopy(addr, ifr.ifr_addr.sa_data, 6); 181 182 /* 183 * open a socket, temporarily, to use for SIOC* ioctls 184 */ 185 if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) { 186 syslog(LOG_ERR, "pfAddMulti: socket: %m"); 187 return (-1); 188 } 189 if (ioctl(fd, SIOCADDMULTI, &ifr) < 0) { 190 syslog(LOG_ERR, "pfAddMulti: SIOCADDMULTI: %m"); 191 close(fd); 192 return (-1); 193 } 194 close(fd); 195 196 return (0); 197 } 198 199 /* 200 * Delete a Multicast address from the interface 201 */ 202 /* ARGSUSED */ 203 int 204 pfDelMulti(int s, char *interface, char *addr) 205 { 206 struct ifreq ifr; 207 int fd; 208 209 strncpy(ifr.ifr_name, interface, sizeof (ifr.ifr_name) - 1); 210 ifr.ifr_name[sizeof(ifr.ifr_name)-1] = 0; 211 212 ifr.ifr_addr.sa_family = AF_UNSPEC; 213 bcopy(addr, ifr.ifr_addr.sa_data, 6); 214 215 /* 216 * open a socket, temporarily, to use for SIOC* ioctls 217 * 218 */ 219 if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) { 220 syslog(LOG_ERR, "pfDelMulti: socket: %m"); 221 return (-1); 222 } 223 if (ioctl(fd, SIOCDELMULTI, &ifr) < 0) { 224 syslog(LOG_ERR, "pfAddMulti: SIOCDELMULTI: %m"); 225 close(fd); 226 return (-1); 227 } 228 close(fd); 229 230 return (0); 231 } 232 233 /* 234 * read a packet 235 */ 236 int 237 pfRead(int fd, u_char *buf, int len) 238 { 239 return (read(fd, buf, len)); 240 } 241 242 /* 243 * write a packet 244 */ 245 int 246 pfWrite(int fd, u_char *buf, int len, int trans) 247 { 248 struct iovec iov[2]; 249 250 /* XXX */ 251 switch (trans) { 252 case TRANS_8023: 253 iov[0].iov_base = buf; 254 iov[0].iov_len = 22; 255 iov[1].iov_base = buf + 22; 256 iov[1].iov_len = len - 22; 257 break; 258 default: 259 iov[0].iov_base = buf; 260 iov[0].iov_len = 14; 261 iov[1].iov_base = buf + 14; 262 iov[1].iov_len = len - 14; 263 break; 264 } 265 266 if (writev(fd, iov, 2) == len) 267 return (len); 268 269 return (-1); 270 } 271 272