| /* |
| * 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: /tcpdump/master/libpcap/savefile.c,v 1.37 1999-10-07 23:46:40 mcr Exp $ (LBL)"; |
| #endif |
| |
| #include <sys/types.h> |
| #include <sys/time.h> |
| |
| #include <errno.h> |
| #include <memory.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <unistd.h> |
| |
| #include "pcap-int.h" |
| |
| #include "gnuc.h" |
| #ifdef HAVE_OS_PROTO_H |
| #include "os-proto.h" |
| #endif |
| |
| #define TCPDUMP_MAGIC 0xa1b2c3d4 |
| |
| /* |
| * 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 */ |
| |
| 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; |
| int linklen; |
| |
| p = (pcap_t *)malloc(sizeof(*p)); |
| if (p == NULL) { |
| strcpy(errbuf, "out of swap"); |
| 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) { |
| sprintf(errbuf, "%s: %s", fname, pcap_strerror(errno)); |
| goto bad; |
| } |
| } |
| if (fread((char *)&hdr, sizeof(hdr), 1, fp) != 1) { |
| sprintf(errbuf, "fread: %s", pcap_strerror(errno)); |
| goto bad; |
| } |
| if (hdr.magic != TCPDUMP_MAGIC) { |
| if (SWAPLONG(hdr.magic) != TCPDUMP_MAGIC) { |
| sprintf(errbuf, "bad dump file format"); |
| goto bad; |
| } |
| p->sf.swapped = 1; |
| swap_hdr(&hdr); |
| } |
| if (hdr.version_major < PCAP_VERSION_MAJOR) { |
| sprintf(errbuf, "archaic file format"); |
| goto bad; |
| } |
| p->tzoff = hdr.thiszone; |
| p->snapshot = hdr.snaplen; |
| p->linktype = 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; |
| } |
| |
| p->sf.base = (u_char *)malloc(p->bufsize + BPF_ALIGNMENT); |
| 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) |
| { |
| FILE *fp = p->sf.rfile; |
| |
| /* read the stamp */ |
| if (fread((char *)hdr, sizeof(struct pcap_pkthdr), 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(hdr->caplen); |
| hdr->len = SWAPLONG(hdr->len); |
| hdr->ts.tv_sec = SWAPLONG(hdr->ts.tv_sec); |
| hdr->ts.tv_usec = SWAPLONG(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) { |
| sprintf(p->errbuf, "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; |
| sprintf(p->errbuf, "BUFMOD hack malloc"); |
| return (-1); |
| } |
| } |
| if (fread((char *)tp, hdr->caplen, 1, fp) != 1) { |
| sprintf(p->errbuf, "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) { |
| sprintf(p->errbuf, "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; |
| |
| f = (FILE *)user; |
| /* XXX we should check the return status */ |
| (void)fwrite((char *)h, sizeof(*h), 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; |
| if (fname[0] == '-' && fname[1] == '\0') |
| f = stdout; |
| else { |
| f = fopen(fname, "w"); |
| if (f == NULL) { |
| sprintf(p->errbuf, "%s: %s", |
| fname, pcap_strerror(errno)); |
| return (NULL); |
| } |
| } |
| (void)sf_write_header(f, p->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); |
| } |