/* $OpenBSD: pf.c,v 1.7 2003/06/04 04:43:56 deraadt Exp $ */ /* * Copyright (c) 1993-95 Mats O Jansson. All rights reserved. * Copyright (c) 1990 The Regents of the University of California. * All rights reserved. * * This code is partly derived from rarpd. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #ifndef LINT static char rcsid[] = "$OpenBSD: pf.c,v 1.7 2003/06/04 04:43:56 deraadt Exp $"; #endif #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "common/mopdef.h" /* * Variables */ extern int errno; extern int promisc; /* * Return information to device.c how to open device. * In this case the driver can handle both Ethernet type II and * IEEE 802.3 frames (SNAP) in a single pfOpen. */ int pfTrans(interface) char *interface; { return TRANS_ETHER+TRANS_8023+TRANS_AND; } /* * Open and initialize packet filter. */ int pfInit(interface, mode, protocol, typ) char *interface; u_short protocol; int typ, mode; { int fd; int n = 0; char device[sizeof "/dev/bpf000"]; struct ifreq ifr; u_int dlt; int immediate; static struct bpf_insn insns[] = { BPF_STMT(BPF_LD | BPF_H | BPF_ABS, 12), BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, 0x4711, 4, 0), BPF_STMT(BPF_LD | BPF_H | BPF_ABS, 20), BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, 0x4711, 0, 3), BPF_STMT(BPF_LD | BPF_H | BPF_ABS, 14), BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, 0xaaaa, 0, 1), BPF_STMT(BPF_RET | BPF_K, 1520), BPF_STMT(BPF_RET | BPF_K, 0), }; static struct bpf_program filter = { sizeof insns / sizeof(insns[0]), insns }; /* Go through all the minors and find one that isn't in use. */ do { (void) snprintf(device, sizeof device, "/dev/bpf%d", n++); fd = open(device, mode); } while (fd < 0 && errno == EBUSY); if (fd < 0) { syslog(LOG_ERR,"pfInit: open bpf %m"); return(-1); } /* Set immediate mode so packets are processed as they arrive. */ immediate = 1; if (ioctl(fd, BIOCIMMEDIATE, &immediate) < 0) { syslog(LOG_ERR,"pfInit: BIOCIMMEDIATE: %m"); return(-1); } (void) strncpy(ifr.ifr_name, interface, sizeof ifr.ifr_name); if (ioctl(fd, BIOCSETIF, (caddr_t) & ifr) < 0) { syslog(LOG_ERR,"pfInit: BIOCSETIF: %m"); return(-1); } /* Check that the data link layer is an Ethernet; this code won't work * with anything else. */ if (ioctl(fd, BIOCGDLT, (caddr_t) & dlt) < 0) { syslog(LOG_ERR,"pfInit: BIOCGDLT: %m"); return(-1); } if (dlt != DLT_EN10MB) { syslog(LOG_ERR,"pfInit: %s is not ethernet", device); return(-1); } if (promisc) { /* Set promiscuous mode. */ if (ioctl(fd, BIOCPROMISC, (caddr_t)0) < 0) { syslog(LOG_ERR,"pfInit: BIOCPROMISC: %m"); return(-1); } } /* Set filter program. */ insns[1].k = protocol; insns[3].k = protocol; if (ioctl(fd, BIOCSETF, (caddr_t) & filter) < 0) { syslog(LOG_ERR,"pfInit: BIOCSETF: %m"); return(-1); } return(fd); } /* * Add a Multicast address to the interface */ int pfAddMulti(s, interface, addr) int s; char *interface, *addr; { struct ifreq ifr; int fd; strncpy(ifr.ifr_name, interface,sizeof(ifr.ifr_name) - 1); ifr.ifr_name[sizeof(ifr.ifr_name)-1] = 0; ifr.ifr_addr.sa_family = AF_UNSPEC; bcopy(addr, ifr.ifr_addr.sa_data, 6); /* * open a socket, temporarily, to use for SIOC* ioctls * */ if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) { syslog(LOG_ERR, "pfAddMulti: socket: %m"); return(-1); } if (ioctl(fd, SIOCADDMULTI, (caddr_t)&ifr) < 0) { syslog(LOG_ERR, "pfAddMulti: SIOCADDMULTI: %m"); close(fd); return(-1); } close(fd); return(0); } /* * Delete a Multicast address from the interface */ int pfDelMulti(s, interface, addr) int s; char *interface, *addr; { struct ifreq ifr; int fd; strncpy(ifr.ifr_name, interface, sizeof (ifr.ifr_name) - 1); ifr.ifr_name[sizeof(ifr.ifr_name)-1] = 0; ifr.ifr_addr.sa_family = AF_UNSPEC; bcopy(addr, ifr.ifr_addr.sa_data, 6); /* * open a socket, temporarily, to use for SIOC* ioctls * */ if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) { syslog(LOG_ERR, "pfDelMulti: socket: %m"); return(-1); } if (ioctl(fd, SIOCDELMULTI, (caddr_t)&ifr) < 0) { syslog(LOG_ERR, "pfAddMulti: SIOCDELMULTI: %m"); close(fd); return(-1); } close(fd); return(0); } /* * read a packet */ int pfRead(fd, buf, len) int fd, len; u_char *buf; { return(read(fd, buf, len)); } /* * write a packet */ int pfWrite(fd, buf, len, trans) int fd, len, trans; u_char *buf; { struct iovec iov[2]; switch (trans) { case TRANS_8023: iov[0].iov_base = (caddr_t)buf; iov[0].iov_len = 22; iov[1].iov_base = (caddr_t)buf+22; iov[1].iov_len = len-22; break; default: iov[0].iov_base = (caddr_t)buf; iov[0].iov_len = 14; iov[1].iov_base = (caddr_t)buf+14; iov[1].iov_len = len-14; break; } if (writev(fd, iov, 2) == len) return(len); return(-1); }