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What we're testing for is byte-swappedness, not raw endianness. 

On a big-endian machine, if the upper 16 bits of the length are non-zero
and the lower 16 bits are zero, that means that the length is
*little*-endian.

What we really care about is whether the file is in the reading host's
native format, so we can just fetch integral values without swapping, or
not in that format, in which case we have to byte-swap integral values.

Rename the variable and redo the code to match.

(This may have caused the PacketLogger reader to fail on big-endian
machines.)

Change-Id: Ie1a82a7d40e2c58c0b8d482d7c95ab60061ca980
Ping-Bug: 10861
Reviewed-on: https://code.wireshark.org/review/34434
Petri-Dish: Guy Harris <guy@alum.mit.edu>
Tested-by: Petri Dish Buildbot
Reviewed-by: Guy Harris <guy@alum.mit.edu>
This commit is contained in:
Guy Harris 2019-09-02 16:09:24 -07:00
parent 6d15429a84
commit 45eadc049e
1 changed files with 14 additions and 17 deletions
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31
wiretap/packetlogger.c
View File

@ -23,7 +23,7 @@
#include "packetlogger.h"
typedef struct {
gboolean little_endian;
gboolean byte_swapped;
} packetlogger_t;
typedef struct packetlogger_header {
@ -39,7 +39,7 @@ static gboolean packetlogger_seek_read(wtap *wth, gint64 seek_off,
wtap_rec *rec,
Buffer *buf, int *err, gchar **err_info);
static gboolean packetlogger_read_header(packetlogger_header_t *pl_hdr,
FILE_T fh, gboolean little_endian,
FILE_T fh, gboolean byte_swapped,
int *err, gchar **err_info);
static gboolean packetlogger_read_packet(wtap *wth, FILE_T fh, wtap_rec *rec,
Buffer *buf, int *err,
@ -47,12 +47,12 @@ static gboolean packetlogger_read_packet(wtap *wth, FILE_T fh, wtap_rec *rec,
wtap_open_return_val packetlogger_open(wtap *wth, int *err, gchar **err_info)
{
gboolean little_endian = FALSE;
gboolean byte_swapped = FALSE;
packetlogger_header_t pl_hdr;
guint8 type;
packetlogger_t *packetlogger;
if(!packetlogger_read_header(&pl_hdr, wth->fh, little_endian,
if(!packetlogger_read_header(&pl_hdr, wth->fh, byte_swapped,
err, err_info)) {
if (*err != 0 && *err != WTAP_ERR_SHORT_READ)
return WTAP_OPEN_ERROR;
@ -67,7 +67,8 @@ wtap_open_return_val packetlogger_open(wtap *wth, int *err, gchar **err_info)
/*
* If the upper 16 bits of the length are non-zero and the lower
* 16 bits are zero, assume the file is little-endian.
* 16 bits are zero, assume the file is byte-swapped from our
* byte order.
*/
if ((pl_hdr.len & 0x0000FFFF) == 0 &&
(pl_hdr.len & 0xFFFF0000) != 0) {
@ -77,7 +78,7 @@ wtap_open_return_val packetlogger_open(wtap *wth, int *err, gchar **err_info)
*/
pl_hdr.len = ((pl_hdr.len >> 24) & 0xFF) |
(((pl_hdr.len >> 16) & 0xFF) << 8);
little_endian = TRUE;
byte_swapped = TRUE;
}
/* Verify this file belongs to us */
@ -91,7 +92,7 @@ wtap_open_return_val packetlogger_open(wtap *wth, int *err, gchar **err_info)
/* This is a PacketLogger file */
packetlogger = (packetlogger_t *)g_malloc(sizeof(packetlogger_t));
packetlogger->little_endian = little_endian;
packetlogger->byte_swapped = byte_swapped;
wth->priv = (void *)packetlogger;
/* Set up the pointers to the handlers for this file type */
@ -132,7 +133,7 @@ packetlogger_seek_read(wtap *wth, gint64 seek_off, wtap_rec *rec,
static gboolean
packetlogger_read_header(packetlogger_header_t *pl_hdr, FILE_T fh,
gboolean little_endian, int *err, gchar **err_info)
gboolean byte_swapped, int *err, gchar **err_info)
{
if (!wtap_read_bytes_or_eof(fh, &pl_hdr->len, 4, err, err_info))
return FALSE;
@ -142,14 +143,10 @@ packetlogger_read_header(packetlogger_header_t *pl_hdr, FILE_T fh,
return FALSE;
/* Convert multi-byte values to host endian */
if (little_endian) {
pl_hdr->len = GUINT32_FROM_LE(pl_hdr->len);
pl_hdr->ts_secs = GUINT32_FROM_LE(pl_hdr->ts_secs);
pl_hdr->ts_usecs = GUINT32_FROM_LE(pl_hdr->ts_usecs);
} else {
pl_hdr->len = GUINT32_FROM_BE(pl_hdr->len);
pl_hdr->ts_secs = GUINT32_FROM_BE(pl_hdr->ts_secs);
pl_hdr->ts_usecs = GUINT32_FROM_BE(pl_hdr->ts_usecs);
if (byte_swapped) {
pl_hdr->len = GUINT32_SWAP_LE_BE(pl_hdr->len);
pl_hdr->ts_secs = GUINT32_SWAP_LE_BE(pl_hdr->ts_secs);
pl_hdr->ts_usecs = GUINT32_SWAP_LE_BE(pl_hdr->ts_usecs);
}
return TRUE;
@ -162,7 +159,7 @@ packetlogger_read_packet(wtap *wth, FILE_T fh, wtap_rec *rec, Buffer *buf,
packetlogger_t *packetlogger = (packetlogger_t *)wth->priv;
packetlogger_header_t pl_hdr;
if(!packetlogger_read_header(&pl_hdr, fh, packetlogger->little_endian,
if(!packetlogger_read_header(&pl_hdr, fh, packetlogger->byte_swapped,
err, err_info))
return FALSE;