/* * Copyright (c) 1993, 1994, 1995, 1996, 1997 * 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. * * savefile.c - supports offline use of tcpdump * Extraction/creation by Jeffrey Mogul, DECWRL * Modified by Steve McCanne, LBL. * * Used to save the received packet headers, after filtering, to * a file, and then read them later. * The first record in the file contains saved values for the machine * dependent values so we can print the dump file on any architecture. */ #ifndef lint static const char rcsid[] = "@(#) $Header: /cvs/Darwin/Libraries/Other/libpcap/libpcap/savefile.c,v 1.1.1.1 2001/07/07 00:41:36 bbraun Exp $ (LBL)"; #endif #ifdef HAVE_CONFIG_H #include "config.h" #endif #include <sys/types.h> #include <sys/time.h> #include <errno.h> #include <memory.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 #define TCPDUMP_MAGIC 0xa1b2c3d4 #define PATCHED_TCPDUMP_MAGIC 0xa1b2cd34 /* * We use the "receiver-makes-right" approach to byte order, * because time is at a premium when we are writing the file. * In other words, the pcap_file_header and pcap_pkthdr, * records are written in host byte order. * Note that the packets are always written in network byte order. * * ntoh[ls] aren't sufficient because we might need to swap on a big-endian * machine (if the file was written in little-end order). */ #define SWAPLONG(y) \ ((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff)) #define SWAPSHORT(y) \ ( (((y)&0xff)<<8) | ((u_short)((y)&0xff00)>>8) ) #define SFERR_TRUNC 1 #define SFERR_BADVERSION 2 #define SFERR_BADF 3 #define SFERR_EOF 4 /* not really an error, just a status */ /* * We don't write DLT_* values to the capture file header, because * they're not the same on all platforms. * * Unfortunately, the various flavors of BSD have not always used the same * numerical values for the same data types, and various patches to * libpcap for non-BSD OSes have added their own DLT_* codes for link * layer encapsulation types seen on those OSes, and those codes have had, * in some cases, values that were also used, on other platforms, for other * link layer encapsulation types. * * This means that capture files of a type whose numerical DLT_* code * means different things on different BSDs, or with different versions * of libpcap, can't always be read on systems other than those like * the one running on the machine on which the capture was made. * * Instead, we define here a set of LINKTYPE_* codes, and map DLT_* codes * to LINKTYPE_* codes when writing a savefile header, and map LINKTYPE_* * codes to DLT_* codes when reading a savefile header. * * For those DLT_* codes that have, as far as we know, the same values on * all platforms (DLT_NULL through DLT_FDDI), we define LINKTYPE_xxx as * DLT_xxx; that way, captures of those types can still be read by * versions of libpcap that map LINKTYPE_* values to DLT_* values, and * captures of those types written by versions of libpcap that map DLT_ * values to LINKTYPE_ values can still be read by older versions * of libpcap. * * The other LINKTYPE_* codes are given values starting at 100, in the * hopes that no DLT_* code will be given one of those values. * * In order to ensure that a given LINKTYPE_* code's value will refer to * the same encapsulation type on all platforms, you should not allocate * a new LINKTYPE_* value without consulting "tcpdump-workers@tcpdump.org". * The tcpdump developers will allocate a value for you, and will not * subsequently allocate it to anybody else; that value will be added to * the "pcap.h" in the tcpdump.org CVS repository, so that a future * libpcap release will include it. * * You should, if possible, also contribute patches to libpcap and tcpdump * to handle the new encapsulation type, so that they can also be checked * into the tcpdump.org CVS repository and so that they will appear in * future libpcap and tcpdump releases. */ #define LINKTYPE_NULL DLT_NULL #define LINKTYPE_ETHERNET DLT_EN10MB /* also for 100Mb and up */ #define LINKTYPE_EXP_ETHERNET DLT_EN3MB /* 3Mb experimental Ethernet */ #define LINKTYPE_AX25 DLT_AX25 #define LINKTYPE_PRONET DLT_PRONET #define LINKTYPE_CHAOS DLT_CHAOS #define LINKTYPE_TOKEN_RING DLT_IEEE802 /* DLT_IEEE802 is used for Token Ring */ #define LINKTYPE_ARCNET DLT_ARCNET #define LINKTYPE_SLIP DLT_SLIP #define LINKTYPE_PPP DLT_PPP #define LINKTYPE_FDDI DLT_FDDI /* * LINKTYPE_PPP is for use when there might, or might not, be an RFC 1662 * PPP in HDLC-like framing header (with 0xff 0x03 before the PPP protocol * field) at the beginning of the packet. * * This is for use when there is always such a header; the address field * might be 0xff, for regular PPP, or it might be an address field for Cisco * point-to-point with HDLC framing as per section 4.3.1 of RFC 1547 ("Cisco * HDLC"). This is, for example, what you get with NetBSD's DLT_PPP_SERIAL. * * We give it the same value as NetBSD's DLT_PPP_SERIAL, in the hopes that * nobody else will choose a DLT_ value of 50, and so that DLT_PPP_SERIAL * captures will be written out with a link type that NetBSD's tcpdump * can read. */ #define LINKTYPE_PPP_HDLC 50 /* PPP in HDLC-like framing */ #define LINKTYPE_ATM_RFC1483 100 /* LLC/SNAP-encapsulated ATM */ #define LINKTYPE_RAW 101 /* raw IP */ #define LINKTYPE_SLIP_BSDOS 102 /* BSD/OS SLIP BPF header */ #define LINKTYPE_PPP_BSDOS 103 /* BSD/OS PPP BPF header */ #define LINKTYPE_C_HDLC 104 /* Cisco HDLC */ #define LINKTYPE_ATM_CLIP 106 /* Linux Classical IP over ATM */ /* * Reserved for future use. */ #define LINKTYPE_IEEE802_11 105 /* IEEE 802.11 (wireless) */ #define LINKTYPE_FR 107 /* BSD/OS Frame Relay */ #define LINKTYPE_LOOP 108 /* OpenBSD loopback */ #define LINKTYPE_ENC 109 /* OpenBSD IPSEC enc */ #define LINKTYPE_LANE8023 110 /* ATM LANE + 802.3 */ #define LINKTYPE_HIPPI 111 /* NetBSD HIPPI */ #define LINKTYPE_HDLC 112 /* NetBSD HDLC framing */ #define LINKTYPE_LINUX_SLL 113 /* Linux cooked socket capture */ static struct linktype_map { int dlt; int linktype; } map[] = { /* * These DLT_* codes have LINKTYPE_* codes with values identical * to the values of the corresponding DLT_* code. */ { DLT_NULL, LINKTYPE_NULL }, { DLT_EN10MB, LINKTYPE_ETHERNET }, { DLT_EN3MB, LINKTYPE_EXP_ETHERNET }, { DLT_AX25, LINKTYPE_AX25 }, { DLT_PRONET, LINKTYPE_PRONET }, { DLT_CHAOS, LINKTYPE_CHAOS }, { DLT_IEEE802, LINKTYPE_TOKEN_RING }, { DLT_ARCNET, LINKTYPE_ARCNET }, { DLT_SLIP, LINKTYPE_SLIP }, { DLT_PPP, LINKTYPE_PPP }, { DLT_FDDI, LINKTYPE_FDDI }, /* * These DLT_* codes have different values on different * platforms; we map them to LINKTYPE_* codes that * have values that should never be equal to any DLT_* * code. */ { DLT_ATM_RFC1483, LINKTYPE_ATM_RFC1483 }, { DLT_RAW, LINKTYPE_RAW }, { DLT_SLIP_BSDOS, LINKTYPE_SLIP_BSDOS }, { DLT_PPP_BSDOS, LINKTYPE_PPP_BSDOS }, /* BSD/OS Cisco HDLC */ { DLT_C_HDLC, LINKTYPE_C_HDLC }, /* * These DLT_* codes are not on all platforms, but, so far, * there don't appear to be any platforms that define * other codes with those values; we map them to * different LINKTYPE_* values anyway, just in case. */ /* Linux ATM Classical IP */ { DLT_ATM_CLIP, LINKTYPE_ATM_CLIP }, /* NetBSD sync/async serial PPP (or Cisco HDLC) */ { DLT_PPP_SERIAL, LINKTYPE_PPP_HDLC }, /* IEEE 802.11 wireless */ { DLT_IEEE802_11, LINKTYPE_IEEE802_11 }, /* OpenBSD loopback */ { DLT_LOOP, LINKTYPE_LOOP }, /* Linux cooked socket capture */ { DLT_LINUX_SLL, LINKTYPE_LINUX_SLL }, /* * Any platform that defines additional DLT_* codes should: * * request a LINKTYPE_* code and value from tcpdump.org, * as per the above; * * add, in their version of libpcap, an entry to map * those DLT_* codes to the corresponding LINKTYPE_* * code; * * redefine, in their "net/bpf.h", any DLT_* values * that collide with the values used by their additional * DLT_* codes, to remove those collisions (but without * making them collide with any of the LINKTYPE_* * values equal to 50 or above; they should also avoid * defining DLT_* values that collide with those * LINKTYPE_* values, either). */ { -1, -1 } }; static int dlt_to_linktype(int dlt) { int i; for (i = 0; map[i].dlt != -1; i++) { if (map[i].dlt == dlt) return (map[i].linktype); } /* * If we don't have a mapping for this DLT_ code, return an * error; that means that the table above needs to have an * entry added. */ return (-1); } static int linktype_to_dlt(int linktype) { int i; for (i = 0; map[i].linktype != -1; i++) { if (map[i].linktype == linktype) return (map[i].dlt); } /* * If we don't have an entry for this link type, return * the link type value; it may be a DLT_ value from an * older version of libpcap. */ return linktype; } static int sf_write_header(FILE *fp, int linktype, int thiszone, int snaplen) { struct pcap_file_header hdr; hdr.magic = TCPDUMP_MAGIC; hdr.version_major = PCAP_VERSION_MAJOR; hdr.version_minor = PCAP_VERSION_MINOR; hdr.thiszone = thiszone; hdr.snaplen = snaplen; hdr.sigfigs = 0; hdr.linktype = linktype; if (fwrite((char *)&hdr, sizeof(hdr), 1, fp) != 1) return (-1); return (0); } static void swap_hdr(struct pcap_file_header *hp) { hp->version_major = SWAPSHORT(hp->version_major); hp->version_minor = SWAPSHORT(hp->version_minor); hp->thiszone = SWAPLONG(hp->thiszone); hp->sigfigs = SWAPLONG(hp->sigfigs); hp->snaplen = SWAPLONG(hp->snaplen); hp->linktype = SWAPLONG(hp->linktype); } pcap_t * pcap_open_offline(const char *fname, char *errbuf) { register pcap_t *p; register FILE *fp; struct pcap_file_header hdr; bpf_u_int32 magic; int linklen; p = (pcap_t *)malloc(sizeof(*p)); if (p == NULL) { strlcpy(errbuf, "out of swap", PCAP_ERRBUF_SIZE); return (NULL); } memset((char *)p, 0, sizeof(*p)); /* * Set this field so we don't close stdin in pcap_close! */ p->fd = -1; if (fname[0] == '-' && fname[1] == '\0') fp = stdin; else { fp = fopen(fname, "r"); if (fp == NULL) { snprintf(errbuf, PCAP_ERRBUF_SIZE, "%s: %s", fname, pcap_strerror(errno)); goto bad; } } if (fread((char *)&hdr, sizeof(hdr), 1, fp) != 1) { snprintf(errbuf, PCAP_ERRBUF_SIZE, "fread: %s", pcap_strerror(errno)); goto bad; } magic = hdr.magic; if (magic != TCPDUMP_MAGIC && magic != PATCHED_TCPDUMP_MAGIC) { magic = SWAPLONG(magic); if (magic != TCPDUMP_MAGIC && magic != PATCHED_TCPDUMP_MAGIC) { snprintf(errbuf, PCAP_ERRBUF_SIZE, "bad dump file format"); goto bad; } p->sf.swapped = 1; swap_hdr(&hdr); } if (magic == PATCHED_TCPDUMP_MAGIC) { /* * XXX - the patch that's in some versions of libpcap * changes the packet header but not the magic number; * we'd have to use some hacks^H^H^H^H^Hheuristics to * detect that. */ p->sf.hdrsize = sizeof(struct pcap_sf_patched_pkthdr); } else p->sf.hdrsize = sizeof(struct pcap_sf_pkthdr); if (hdr.version_major < PCAP_VERSION_MAJOR) { snprintf(errbuf, PCAP_ERRBUF_SIZE, "archaic file format"); goto bad; } p->tzoff = hdr.thiszone; p->snapshot = hdr.snaplen; p->linktype = linktype_to_dlt(hdr.linktype); p->sf.rfile = fp; p->bufsize = hdr.snaplen; /* Align link header as required for proper data alignment */ /* XXX should handle all types */ switch (p->linktype) { case DLT_EN10MB: linklen = 14; break; case DLT_FDDI: linklen = 13 + 8; /* fddi_header + llc */ break; case DLT_NULL: default: linklen = 0; break; } if (p->bufsize < 0) p->bufsize = BPF_MAXBUFSIZE; p->sf.base = (u_char *)malloc(p->bufsize + BPF_ALIGNMENT); if (p->sf.base == NULL) { strlcpy(errbuf, "out of swap", PCAP_ERRBUF_SIZE); goto bad; } p->buffer = p->sf.base + BPF_ALIGNMENT - (linklen % BPF_ALIGNMENT); p->sf.version_major = hdr.version_major; p->sf.version_minor = hdr.version_minor; #ifdef PCAP_FDDIPAD /* XXX padding only needed for kernel fcode */ pcap_fddipad = 0; #endif return (p); bad: free(p); return (NULL); } /* * Read sf_readfile and return the next packet. Return the header in hdr * and the contents in buf. Return 0 on success, SFERR_EOF if there were * no more packets, and SFERR_TRUNC if a partial packet was encountered. */ static int sf_next_packet(pcap_t *p, struct pcap_pkthdr *hdr, u_char *buf, int buflen) { struct pcap_sf_patched_pkthdr sf_hdr; FILE *fp = p->sf.rfile; /* * Read the packet header; the structure we use as a buffer * is the longer structure for files generated by the patched * libpcap, but if the file has the magic number for an * unpatched libpcap we only read as many bytes as the regular * header has. */ if (fread(&sf_hdr, p->sf.hdrsize, 1, fp) != 1) { /* probably an EOF, though could be a truncated packet */ return (1); } if (p->sf.swapped) { /* these were written in opposite byte order */ hdr->caplen = SWAPLONG(sf_hdr.caplen); hdr->len = SWAPLONG(sf_hdr.len); hdr->ts.tv_sec = SWAPLONG(sf_hdr.ts.tv_sec); hdr->ts.tv_usec = SWAPLONG(sf_hdr.ts.tv_usec); } else { hdr->caplen = sf_hdr.caplen; hdr->len = sf_hdr.len; hdr->ts.tv_sec = sf_hdr.ts.tv_sec; hdr->ts.tv_usec = sf_hdr.ts.tv_usec; } /* * We interchanged the caplen and len fields at version 2.3, * in order to match the bpf header layout. But unfortunately * some files were written with version 2.3 in their headers * but without the interchanged fields. */ if (p->sf.version_minor < 3 || (p->sf.version_minor == 3 && hdr->caplen > hdr->len)) { int t = hdr->caplen; hdr->caplen = hdr->len; hdr->len = t; } if (hdr->caplen > buflen) { /* * This can happen due to Solaris 2.3 systems tripping * over the BUFMOD problem and not setting the snapshot * correctly in the savefile header. If the caplen isn't * grossly wrong, try to salvage. */ static u_char *tp = NULL; static int tsize = 0; if (hdr->caplen > 65535) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "bogus savefile header"); return (-1); } if (tsize < hdr->caplen) { tsize = ((hdr->caplen + 1023) / 1024) * 1024; if (tp != NULL) free((u_char *)tp); tp = (u_char *)malloc(tsize); if (tp == NULL) { tsize = 0; snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BUFMOD hack malloc"); return (-1); } } if (fread((char *)tp, hdr->caplen, 1, fp) != 1) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "truncated dump file"); return (-1); } /* * We can only keep up to buflen bytes. Since caplen > buflen * is exactly how we got here, we know we can only keep the * first buflen bytes and must drop the remainder. Adjust * caplen accordingly, so we don't get confused later as * to how many bytes we have to play with. */ hdr->caplen = buflen; memcpy((char *)buf, (char *)tp, buflen); } else { /* read the packet itself */ if (fread((char *)buf, hdr->caplen, 1, fp) != 1) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "truncated dump file"); return (-1); } } return (0); } /* * Print out packets stored in the file initialized by sf_read_init(). * If cnt > 0, return after 'cnt' packets, otherwise continue until eof. */ int pcap_offline_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user) { struct bpf_insn *fcode = p->fcode.bf_insns; int status = 0; int n = 0; while (status == 0) { struct pcap_pkthdr h; status = sf_next_packet(p, &h, p->buffer, p->bufsize); if (status) { if (status == 1) return (0); return (status); } if (fcode == NULL || bpf_filter(fcode, p->buffer, h.len, h.caplen)) { (*callback)(user, &h, p->buffer); if (++n >= cnt && cnt > 0) break; } } /*XXX this breaks semantics tcpslice expects */ return (n); } /* * Output a packet to the initialized dump file. */ void pcap_dump(u_char *user, const struct pcap_pkthdr *h, const u_char *sp) { register FILE *f; struct pcap_sf_pkthdr sf_hdr; f = (FILE *)user; sf_hdr.ts.tv_sec = h->ts.tv_sec; sf_hdr.ts.tv_usec = h->ts.tv_usec; sf_hdr.caplen = h->caplen; sf_hdr.len = h->len; /* XXX we should check the return status */ (void)fwrite(&sf_hdr, sizeof(sf_hdr), 1, f); (void)fwrite((char *)sp, h->caplen, 1, f); } /* * Initialize so that sf_write() will output to the file named 'fname'. */ pcap_dumper_t * pcap_dump_open(pcap_t *p, const char *fname) { FILE *f; int linktype; linktype = dlt_to_linktype(p->linktype); if (linktype == -1) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "%s: link-layer type %d isn't supported in savefiles", fname, linktype); return (NULL); } if (fname[0] == '-' && fname[1] == '\0') f = stdout; else { f = fopen(fname, "w"); if (f == NULL) { snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "%s: %s", fname, pcap_strerror(errno)); return (NULL); } } (void)sf_write_header(f, linktype, p->tzoff, p->snapshot); return ((pcap_dumper_t *)f); } void pcap_dump_close(pcap_dumper_t *p) { #ifdef notyet if (ferror((FILE *)p)) return-an-error; /* XXX should check return from fclose() too */ #endif (void)fclose((FILE *)p); }