diff options
Diffstat (limited to 'wiretap/i4btrace.c')
| -rw-r--r-- | wiretap/i4btrace.c | 56 |
1 files changed, 49 insertions, 7 deletions
diff --git a/wiretap/i4btrace.c b/wiretap/i4btrace.c index 2445b9c490..80df4367b7 100644 --- a/wiretap/i4btrace.c +++ b/wiretap/i4btrace.c @@ -1,6 +1,6 @@ /* i4btrace.c * - * $Id: i4btrace.c,v 1.1 1999/12/12 22:40:09 gram Exp $ + * $Id: i4btrace.c,v 1.2 1999/12/15 02:25:50 guy Exp $ * * Wiretap Library * Copyright (c) 1999 by Bert Driehuis <driehuis@playbeing.org> @@ -34,10 +34,19 @@ static int i4btrace_read(wtap *wth, int *err); +/* + * Test some fields in the header to see if they make sense. + */ +#define I4B_HDR_IS_OK(hdr) \ + (!((unsigned)hdr.length < 3 || (unsigned)hdr.unit > 4 || \ + (unsigned)hdr.type > 4 || (unsigned)hdr.dir > 2 || \ + (unsigned)hdr.trunc > 2048)) + int i4btrace_open(wtap *wth, int *err) { int bytes_read; i4b_trace_hdr_t hdr; + gboolean byte_swapped = FALSE; /* I4B trace files have no magic in the header... Sigh */ file_seek(wth->fh, 0, SEEK_SET); @@ -51,10 +60,28 @@ int i4btrace_open(wtap *wth, int *err) } /* Silly heuristic... */ - if ((unsigned)hdr.length < 3 || (unsigned)hdr.unit > 4 || - (unsigned)hdr.type > 4 || (unsigned)hdr.dir > 2 || - (unsigned)hdr.trunc > 2048) - return 0; + if (!I4B_HDR_IS_OK(hdr)) { + /* + * OK, try byte-swapping the header fields. + */ + hdr.length = BSWAP32(hdr.length); + hdr.unit = BSWAP32(hdr.unit); + hdr.type = BSWAP32(hdr.type); + hdr.dir = BSWAP32(hdr.dir); + hdr.trunc = BSWAP32(hdr.trunc); + if (!I4B_HDR_IS_OK(hdr)) { + /* + * It doesn't look valid in either byte order. + */ + return 0; + } + + /* + * It looks valid byte-swapped, so assume it's a + * trace written in the opposite byte order. + */ + byte_swapped = TRUE; + } file_seek(wth->fh, 0, SEEK_SET); wth->data_offset = 0; @@ -69,6 +96,7 @@ int i4btrace_open(wtap *wth, int *err) wth->capture.i4btrace->start = hdr.time.tv_sec; wth->capture.i4btrace->bchannel_prot[0] = -1; wth->capture.i4btrace->bchannel_prot[1] = -1; + wth->capture.i4btrace->byte_swapped = byte_swapped; wth->file_encap = WTAP_ENCAP_PER_PACKET; @@ -100,8 +128,22 @@ static int i4btrace_read(wtap *wth, int *err) return 0; } wth->data_offset += sizeof hdr; - length = pletohs(&hdr.length) - sizeof(hdr); - if (length == 0) return 0; + if (wth->capture.i4btrace->byte_swapped) { + /* + * Byte-swap the header. + */ + hdr.length = BSWAP32(hdr.length); + hdr.unit = BSWAP32(hdr.unit); + hdr.type = BSWAP32(hdr.type); + hdr.dir = BSWAP32(hdr.dir); + hdr.trunc = BSWAP32(hdr.trunc); + hdr.count = BSWAP32(hdr.count); + hdr.time.tv_sec = BSWAP32(hdr.time.tv_sec); + hdr.time.tv_usec = BSWAP32(hdr.time.tv_usec); + } + length = hdr.length - sizeof(hdr); + if (length == 0) + return 0; wth->phdr.len = length; wth->phdr.caplen = length; |