/* $OpenBSD: pcap-bpf.c,v 1.20 2006/03/26 20:58:51 djm Exp $ */ /* * Copyright (c) 1993, 1994, 1995, 1996, 1998 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that: (1) source code distributions * retain the above copyright notice and this paragraph in its entirety, (2) * distributions including binary code include the above copyright notice and * this paragraph in its entirety in the documentation or other materials * provided with the distribution, and (3) all advertising materials mentioning * features or use of this software display the following acknowledgement: * ``This product includes software developed by the University of California, * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of * the University nor the names of its contributors may be used to endorse * or promote products derived from this software without specific prior * written permission. * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. */ #include <sys/param.h> /* optionally get BSD define */ #include <sys/time.h> #include <sys/timeb.h> #include <sys/socket.h> #include <sys/ioctl.h> #include <net/if.h> #include <ctype.h> #include <errno.h> #include <fcntl.h> #include <netdb.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include "pcap-int.h" #ifdef HAVE_OS_PROTO_H #include "os-proto.h" #endif #include "gencode.h" int pcap_stats(pcap_t *p, struct pcap_stat *ps) { struct bpf_stat s; if (ioctl(p->fd, BIOCGSTATS, (caddr_t)&s) < 0) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCGSTATS: %s", pcap_strerror(errno)); return (-1); } ps->ps_recv = s.bs_recv; ps->ps_drop = s.bs_drop; return (0); } int pcap_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user) { int cc; int n = 0; register u_char *bp, *ep; again: /* * Has "pcap_breakloop()" been called? */ if (p->break_loop) { /* * Yes - clear the flag that indicates that it * has, and return -2 to indicate that we were * told to break out of the loop. */ p->break_loop = 0; return (-2); } cc = p->cc; if (p->cc == 0) { cc = read(p->fd, (char *)p->buffer, p->bufsize); if (cc < 0) { /* Don't choke when we get ptraced */ switch (errno) { case EINTR: goto again; case EWOULDBLOCK: return (0); #if defined(sun) && !defined(BSD) /* * Due to a SunOS bug, after 2^31 bytes, the kernel * file offset overflows and read fails with EINVAL. * The lseek() to 0 will fix things. */ case EINVAL: if (lseek(p->fd, 0L, SEEK_CUR) + p->bufsize < 0) { (void)lseek(p->fd, 0L, SEEK_SET); goto again; } /* FALLTHROUGH */ #endif } snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "read: %s", pcap_strerror(errno)); return (-1); } bp = p->buffer; } else bp = p->bp; /* * Loop through each packet. */ #define bhp ((struct bpf_hdr *)bp) ep = bp + cc; while (bp < ep) { register int caplen, hdrlen; /* * Has "pcap_breakloop()" been called? * If so, return immediately - if we haven't read any * packets, clear the flag and return -2 to indicate * that we were told to break out of the loop, otherwise * leave the flag set, so that the *next* call will break * out of the loop without having read any packets, and * return the number of packets we've processed so far. */ if (p->break_loop) { if (n == 0) { p->break_loop = 0; return (-2); } else { p->bp = bp; p->cc = ep - bp; return (n); } } caplen = bhp->bh_caplen; hdrlen = bhp->bh_hdrlen; /* * XXX A bpf_hdr matches a pcap_pkthdr. */ (*callback)(user, (struct pcap_pkthdr*)bp, bp + hdrlen); bp += BPF_WORDALIGN(caplen + hdrlen); if (++n >= cnt && cnt > 0) { p->bp = bp; p->cc = ep - bp; return (n); } } #undef bhp p->cc = 0; return (n); } int pcap_inject(pcap_t *p, const void *buf, size_t len) { return (write(p->fd, buf, len)); } int pcap_sendpacket(pcap_t *p, const u_char *buf, int size) { return (pcap_inject(p, buf, size) == -1 ? -1 : 0); } /* ARGSUSED */ static __inline int bpf_open(pcap_t *p, char *errbuf) { int fd; int n = 0; char device[sizeof "/dev/bpf0000000000"]; /* * 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, O_RDWR); if (fd < 0 && errno == EACCES) fd = open(device, O_RDONLY); } while (fd < 0 && errno == EBUSY); /* * XXX better message for all minors used */ if (fd < 0) snprintf(errbuf, PCAP_ERRBUF_SIZE, "%s: %s", device, pcap_strerror(errno)); return (fd); } pcap_t * pcap_open_live(const char *device, int snaplen, int promisc, int to_ms, char *ebuf) { int fd; struct ifreq ifr; struct bpf_version bv; u_int v; pcap_t *p; struct bpf_dltlist bdl; bzero(&bdl, sizeof(bdl)); p = (pcap_t *)malloc(sizeof(*p)); if (p == NULL) { snprintf(ebuf, PCAP_ERRBUF_SIZE, "malloc: %s", pcap_strerror(errno)); return (NULL); } bzero(p, sizeof(*p)); fd = bpf_open(p, ebuf); if (fd < 0) goto bad; p->fd = fd; p->snapshot = snaplen; if (ioctl(fd, BIOCVERSION, (caddr_t)&bv) < 0) { snprintf(ebuf, PCAP_ERRBUF_SIZE, "BIOCVERSION: %s", pcap_strerror(errno)); goto bad; } if (bv.bv_major != BPF_MAJOR_VERSION || bv.bv_minor < BPF_MINOR_VERSION) { snprintf(ebuf, PCAP_ERRBUF_SIZE, "kernel bpf filter out of date"); goto bad; } #if 0 /* Just use the kernel default */ v = 32768; /* XXX this should be a user-accessible hook */ /* Ignore the return value - this is because the call fails on * BPF systems that don't have kernel malloc. And if the call * fails, it's no big deal, we just continue to use the standard * buffer size. */ (void) ioctl(fd, BIOCSBLEN, (caddr_t)&v); #endif (void)strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name)); if (ioctl(fd, BIOCSETIF, (caddr_t)&ifr) < 0) { snprintf(ebuf, PCAP_ERRBUF_SIZE, "%s: %s", device, pcap_strerror(errno)); goto bad; } /* Get the data link layer type. */ if (ioctl(fd, BIOCGDLT, (caddr_t)&v) < 0) { snprintf(ebuf, PCAP_ERRBUF_SIZE, "BIOCGDLT: %s", pcap_strerror(errno)); goto bad; } #if _BSDI_VERSION - 0 >= 199510 /* The SLIP and PPP link layer header changed in BSD/OS 2.1 */ switch (v) { case DLT_SLIP: v = DLT_SLIP_BSDOS; break; case DLT_PPP: v = DLT_PPP_BSDOS; break; } #endif p->linktype = v; /* * We know the default link type -- now determine all the DLTs * this interface supports. If this fails with EINVAL, it's * not fatal; we just don't get to use the feature later. */ if (ioctl(fd, BIOCGDLTLIST, (caddr_t)&bdl) == 0) { bdl.bfl_list = (u_int *) calloc(bdl.bfl_len + 1, sizeof(u_int)); if (bdl.bfl_list == NULL) { (void)snprintf(ebuf, PCAP_ERRBUF_SIZE, "malloc: %s", pcap_strerror(errno)); goto bad; } if (ioctl(fd, BIOCGDLTLIST, (caddr_t)&bdl) < 0) { (void)snprintf(ebuf, PCAP_ERRBUF_SIZE, "BIOCGDLTLIST: %s", pcap_strerror(errno)); goto bad; } p->dlt_count = bdl.bfl_len; p->dlt_list = bdl.bfl_list; } else { if (errno != EINVAL) { (void)snprintf(ebuf, PCAP_ERRBUF_SIZE, "BIOCGDLTLIST: %s", pcap_strerror(errno)); goto bad; } } /* set timeout */ if (to_ms != 0) { struct timeval to; to.tv_sec = to_ms / 1000; to.tv_usec = (to_ms * 1000) % 1000000; if (ioctl(p->fd, BIOCSRTIMEOUT, (caddr_t)&to) < 0) { snprintf(ebuf, PCAP_ERRBUF_SIZE, "BIOCSRTIMEOUT: %s", pcap_strerror(errno)); goto bad; } } if (promisc) /* set promiscuous mode, okay if it fails */ (void)ioctl(p->fd, BIOCPROMISC, NULL); if (ioctl(fd, BIOCGBLEN, (caddr_t)&v) < 0) { snprintf(ebuf, PCAP_ERRBUF_SIZE, "BIOCGBLEN: %s", pcap_strerror(errno)); goto bad; } p->bufsize = v; p->buffer = (u_char *)malloc(p->bufsize); if (p->buffer == NULL) { snprintf(ebuf, PCAP_ERRBUF_SIZE, "malloc: %s", pcap_strerror(errno)); goto bad; } return (p); bad: if (fd >= 0) (void)close(fd); free(bdl.bfl_list); free(p); return (NULL); } int pcap_setfilter(pcap_t *p, struct bpf_program *fp) { size_t buflen; /* * It looks that BPF code generated by gen_protochain() is not * compatible with some of kernel BPF code (for example BSD/OS 3.1). * Take a safer side for now. */ if (no_optimize || (p->sf.rfile != NULL)){ if (p->fcode.bf_insns != NULL) pcap_freecode(&p->fcode); buflen = sizeof(*fp->bf_insns) * fp->bf_len; p->fcode.bf_len = fp->bf_len; p->fcode.bf_insns = malloc(buflen); if (p->fcode.bf_insns == NULL) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "malloc: %s", pcap_strerror(errno)); return (-1); } memcpy(p->fcode.bf_insns, fp->bf_insns, buflen); } else if (ioctl(p->fd, BIOCSETF, (caddr_t)fp) < 0) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSETF: %s", pcap_strerror(errno)); return (-1); } return (0); } int pcap_setdirection(pcap_t *p, pcap_direction_t d) { u_int dirfilt; switch (d) { case PCAP_D_INOUT: dirfilt = 0; break; case PCAP_D_IN: dirfilt = BPF_DIRECTION_OUT; break; case PCAP_D_OUT: dirfilt = BPF_DIRECTION_IN; break; default: snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "Invalid direction"); return (-1); } if (ioctl(p->fd, BIOCSDIRFILT, &dirfilt) < 0) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSDIRFILT: %s", pcap_strerror(errno)); return (-1); } return (0); } int pcap_set_datalink(pcap_t *p, int dlt) { int i; if (p->dlt_count == 0) { /* * We couldn't fetch the list of DLTs, or we don't * have a "set datalink" operation, which means * this platform doesn't support changing the * DLT for an interface. Check whether the new * DLT is the one this interface supports. */ if (p->linktype != dlt) goto unsupported; /* * It is, so there's nothing we need to do here. */ return (0); } for (i = 0; i < p->dlt_count; i++) if (p->dlt_list[i] == dlt) break; if (i >= p->dlt_count) goto unsupported; if (ioctl(p->fd, BIOCSDLT, &dlt) == -1) { (void) snprintf(p->errbuf, sizeof(p->errbuf), "Cannot set DLT %d: %s", dlt, strerror(errno)); return (-1); } p->linktype = dlt; return (0); unsupported: (void) snprintf(p->errbuf, sizeof(p->errbuf), "DLT %d is not one of the DLTs supported by this device", dlt); return (-1); }