1 /* $OpenBSD: pf.c,v 1.16 2016/05/28 07:00:18 natano 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 struct ifreq ifr; 83 u_int dlt; 84 int immediate; 85 86 static struct bpf_insn insns[] = { 87 BPF_STMT(BPF_LD | BPF_H | BPF_ABS, 12), 88 BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, 0x4711, 4, 0), 89 BPF_STMT(BPF_LD | BPF_H | BPF_ABS, 20), 90 BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, 0x4711, 0, 3), 91 BPF_STMT(BPF_LD | BPF_H | BPF_ABS, 14), 92 BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, 0xaaaa, 0, 1), 93 BPF_STMT(BPF_RET | BPF_K, 1520), 94 BPF_STMT(BPF_RET | BPF_K, 0), 95 }; 96 static struct bpf_program filter = { 97 sizeof insns / sizeof(insns[0]), 98 insns 99 }; 100 101 if ((fd = open("/dev/bpf0", mode)) == -1) { 102 syslog(LOG_ERR,"pfInit: open bpf %m"); 103 return (-1); 104 } 105 106 /* Set immediate mode so packets are processed as they arrive. */ 107 immediate = 1; 108 if (ioctl(fd, BIOCIMMEDIATE, &immediate) < 0) { 109 syslog(LOG_ERR,"pfInit: BIOCIMMEDIATE: %m"); 110 return (-1); 111 } 112 strncpy(ifr.ifr_name, interface, sizeof ifr.ifr_name); 113 if (ioctl(fd, BIOCSETIF, &ifr) < 0) { 114 syslog(LOG_ERR,"pfInit: BIOCSETIF: %m"); 115 return (-1); 116 } 117 /* Check that the data link layer is an Ethernet; this code won't work 118 * with anything else. */ 119 if (ioctl(fd, BIOCGDLT, &dlt) < 0) { 120 syslog(LOG_ERR,"pfInit: BIOCGDLT: %m"); 121 return (-1); 122 } 123 if (dlt != DLT_EN10MB) { 124 syslog(LOG_ERR,"pfInit: %s is not ethernet", interface); 125 return (-1); 126 } 127 if (promisc) 128 /* Set promiscuous mode. */ 129 if (ioctl(fd, BIOCPROMISC, 0) < 0) { 130 syslog(LOG_ERR,"pfInit: BIOCPROMISC: %m"); 131 return (-1); 132 } 133 134 /* Set filter program. */ 135 insns[1].k = protocol; 136 insns[3].k = protocol; 137 138 if (ioctl(fd, BIOCSETF, &filter) < 0) { 139 syslog(LOG_ERR,"pfInit: BIOCSETF: %m"); 140 return (-1); 141 } 142 143 /* XXX set the same write filter (for protocol only) */ 144 if (ioctl(fd, BIOCSETWF, &filter) < 0) { 145 syslog(LOG_ERR,"pfInit: BIOCSETWF: %m"); 146 return (-1); 147 } 148 149 /* Lock the interface to prevent further changes */ 150 if (ioctl(fd, BIOCLOCK) < 0) { 151 syslog(LOG_ERR,"pfInit: BIOCLOCK: %m"); 152 return (-1); 153 } 154 155 return (fd); 156 } 157 158 /* 159 * Add a Multicast address to the interface 160 */ 161 /* ARGSUSED */ 162 int 163 pfAddMulti(int s, char *interface, char *addr) 164 { 165 struct ifreq ifr; 166 int fd; 167 168 strncpy(ifr.ifr_name, interface, sizeof(ifr.ifr_name) - 1); 169 ifr.ifr_name[sizeof(ifr.ifr_name) - 1] = 0; 170 171 ifr.ifr_addr.sa_family = AF_UNSPEC; 172 bcopy(addr, ifr.ifr_addr.sa_data, 6); 173 174 /* 175 * open a socket, temporarily, to use for SIOC* ioctls 176 */ 177 if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) { 178 syslog(LOG_ERR, "pfAddMulti: socket: %m"); 179 return (-1); 180 } 181 if (ioctl(fd, SIOCADDMULTI, &ifr) < 0) { 182 syslog(LOG_ERR, "pfAddMulti: SIOCADDMULTI: %m"); 183 close(fd); 184 return (-1); 185 } 186 close(fd); 187 188 return (0); 189 } 190 191 /* 192 * Delete a Multicast address from the interface 193 */ 194 /* ARGSUSED */ 195 int 196 pfDelMulti(int s, char *interface, char *addr) 197 { 198 struct ifreq ifr; 199 int fd; 200 201 strncpy(ifr.ifr_name, interface, sizeof (ifr.ifr_name) - 1); 202 ifr.ifr_name[sizeof(ifr.ifr_name)-1] = 0; 203 204 ifr.ifr_addr.sa_family = AF_UNSPEC; 205 bcopy(addr, ifr.ifr_addr.sa_data, 6); 206 207 /* 208 * open a socket, temporarily, to use for SIOC* ioctls 209 * 210 */ 211 if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) { 212 syslog(LOG_ERR, "pfDelMulti: socket: %m"); 213 return (-1); 214 } 215 if (ioctl(fd, SIOCDELMULTI, &ifr) < 0) { 216 syslog(LOG_ERR, "pfAddMulti: SIOCDELMULTI: %m"); 217 close(fd); 218 return (-1); 219 } 220 close(fd); 221 222 return (0); 223 } 224 225 /* 226 * read a packet 227 */ 228 int 229 pfRead(int fd, u_char *buf, int len) 230 { 231 return (read(fd, buf, len)); 232 } 233 234 /* 235 * write a packet 236 */ 237 int 238 pfWrite(int fd, u_char *buf, int len, int trans) 239 { 240 struct iovec iov[2]; 241 242 /* XXX */ 243 switch (trans) { 244 case TRANS_8023: 245 iov[0].iov_base = buf; 246 iov[0].iov_len = 22; 247 iov[1].iov_base = buf + 22; 248 iov[1].iov_len = len - 22; 249 break; 250 default: 251 iov[0].iov_base = buf; 252 iov[0].iov_len = 14; 253 iov[1].iov_base = buf + 14; 254 iov[1].iov_len = len - 14; 255 break; 256 } 257 258 if (writev(fd, iov, 2) == len) 259 return (len); 260 261 return (-1); 262 } 263 264