static gboolean
netmon_seek_read(wtap *wth, gint64 seek_off,
struct wtap_pkthdr *phdr, guint8 *pd, int length,
int *err, gchar **err_info)
{
union wtap_pseudo_header *pseudo_header = &phdr->pseudo_header;
netmon_t *netmon = (netmon_t *)wth->priv;
int trlr_size;
int pkt_encap;
if (file_seek(wth->random_fh, seek_off, SEEK_SET, err) == -1)
return FALSE;
switch (wth->file_encap) {
case WTAP_ENCAP_ATM_PDUS:
if (!netmon_read_atm_pseudoheader(wth->random_fh, pseudo_header,
err, err_info)) {
/* Read error */
return FALSE;
}
break;
}
/*
* Read the packet data.
*/
if (!netmon_read_rec_data(wth->random_fh, pd, length, err, err_info))
return FALSE;
/*
* For version 2.1 and later, there's additional information
* after the frame data.
*/
trlr_size = (int)netmon_trailer_size(netmon);
if (trlr_size != 0) {
/*
* I haz a trailer.
*/
pkt_encap = netmon_read_rec_trailer(wth->random_fh,
trlr_size, err, err_info);
if (pkt_encap == -1)
return FALSE; /* error */
if (pkt_encap == 0) {
/*
* This should not happen.
*/
*err = WTAP_ERR_BAD_FILE;
*err_info = g_strdup("netmon: saw metadata in netmon_seek_read");
return FALSE;
}
netmon_set_pseudo_header_info(pkt_encap, pseudo_header,
pd, length);
} else {
netmon_set_pseudo_header_info(wth->file_encap, pseudo_header,
pd, length);
}
return TRUE;
}
static process_trailer_retval netmon_process_rec_trailer(netmon_t *netmon,
FILE_T fh, struct wtap_pkthdr *phdr, int *err, gchar **err_info)
{
int trlr_size;
trlr_size = (int)netmon_trailer_size(netmon);
if (trlr_size != 0) {
/*
* I haz a trailer.
*/
phdr->pkt_encap = netmon_read_rec_trailer(fh,
trlr_size, err, err_info);
if (phdr->pkt_encap == -1)
return FAILURE; /* error */
if (phdr->pkt_encap == 0)
return RETRY;
}
return SUCCESS;
}
/* Read the next packet */
static gboolean netmon_read(wtap *wth, int *err, gchar **err_info,
gint64 *data_offset)
{
netmon_t *netmon = (netmon_t *)wth->priv;
guint32 packet_size = 0;
guint32 orig_size = 0;
int bytes_read;
union {
struct netmonrec_1_x_hdr hdr_1_x;
struct netmonrec_2_x_hdr hdr_2_x;
} hdr;
int hdr_size = 0;
int trlr_size;
gint64 rec_offset;
guint8 *data_ptr;
gint64 delta = 0; /* signed - frame times can be before the nominal start */
gint64 t;
time_t secs;
guint32 nsecs;
again:
/* Have we reached the end of the packet data? */
if (netmon->current_frame >= netmon->frame_table_size) {
/* Yes. We won't need the frame table any more;
free it. */
g_free(netmon->frame_table);
netmon->frame_table = NULL;
*err = 0; /* it's just an EOF, not an error */
return FALSE;
}
/* Seek to the beginning of the current record, if we're
not there already (seeking to the current position
may still cause a seek and a read of the underlying file,
so we don't want to do it unconditionally).
Yes, the current record could be before the previous
record. At least some captures put the trailer record
with statistics as the first physical record in the
file, but set the frame table up so it's the last
record in sequence. */
rec_offset = netmon->frame_table[netmon->current_frame];
if (wth->data_offset != rec_offset) {
wth->data_offset = rec_offset;
if (file_seek(wth->fh, wth->data_offset, SEEK_SET, err) == -1)
return FALSE;
}
netmon->current_frame++;
/* Read record header. */
switch (netmon->version_major) {
case 1:
hdr_size = sizeof (struct netmonrec_1_x_hdr);
break;
case 2:
hdr_size = sizeof (struct netmonrec_2_x_hdr);
break;
}
errno = WTAP_ERR_CANT_READ;
bytes_read = file_read(&hdr, hdr_size, wth->fh);
if (bytes_read != hdr_size) {
*err = file_error(wth->fh, err_info);
if (*err == 0 && bytes_read != 0) {
*err = WTAP_ERR_SHORT_READ;
}
return FALSE;
}
wth->data_offset += hdr_size;
switch (netmon->version_major) {
case 1:
orig_size = pletohs(&hdr.hdr_1_x.orig_len);
packet_size = pletohs(&hdr.hdr_1_x.incl_len);
break;
case 2:
orig_size = pletohl(&hdr.hdr_2_x.orig_len);
packet_size = pletohl(&hdr.hdr_2_x.incl_len);
break;
}
if (packet_size > WTAP_MAX_PACKET_SIZE) {
/*
* Probably a corrupt capture file; don't blow up trying
* to allocate space for an immensely-large packet.
*/
*err = WTAP_ERR_BAD_FILE;
*err_info = g_strdup_printf("netmon: File has %u-byte packet, bigger than maximum of %u",
packet_size, WTAP_MAX_PACKET_SIZE);
return FALSE;
}
*data_offset = wth->data_offset;
/*
* If this is an ATM packet, the first
* "sizeof (struct netmon_atm_hdr)" bytes have destination and
* source addresses (6 bytes - MAC addresses of some sort?)
* and the VPI and VCI; read them and generate the pseudo-header
* from them.
*/
switch (wth->file_encap) {
case WTAP_ENCAP_ATM_PDUS:
if (packet_size < sizeof (struct netmon_atm_hdr)) {
/*
* Uh-oh, the packet isn't big enough to even
* have a pseudo-header.
*/
*err = WTAP_ERR_BAD_FILE;
*err_info = g_strdup_printf("netmon: ATM file has a %u-byte packet, too small to have even an ATM pseudo-header",
packet_size);
return FALSE;
}
if (!netmon_read_atm_pseudoheader(wth->fh, &wth->pseudo_header,
err, err_info))
return FALSE; /* Read error */
/*
* Don't count the pseudo-header as part of the packet.
*/
orig_size -= (guint)sizeof (struct netmon_atm_hdr);
packet_size -= (guint)sizeof (struct netmon_atm_hdr);
wth->data_offset += sizeof (struct netmon_atm_hdr);
break;
default:
break;
}
buffer_assure_space(wth->frame_buffer, packet_size);
data_ptr = buffer_start_ptr(wth->frame_buffer);
if (!netmon_read_rec_data(wth->fh, data_ptr, packet_size, err,
err_info))
return FALSE; /* Read error */
wth->data_offset += packet_size;
switch (netmon->version_major) {
case 1:
/*
* According to Paul Long, this offset is unsigned.
* It's 32 bits, so the maximum value will fit in
* a gint64 such as delta, even after multiplying
* it by 1000000.
*
* pletohl() returns a guint32; we cast it to gint64
* before multiplying, so that the product doesn't
* overflow a guint32.
*/
delta = ((gint64)pletohl(&hdr.hdr_1_x.ts_delta))*1000000;
break;
case 2:
/*
* OK, this is weird. Microsoft's documentation
* says this is in microseconds and is a 64-bit
* unsigned number, but it can be negative; they
* say what appears to amount to "treat it as an
* unsigned number, multiply it by 10, and then
* interpret the resulting 64-bit quantity as a
* signed number". That operation can turn a
* value with the uppermost bit 0 to a value with
* the uppermost bit 1, hence turning a large
* positive number-of-microseconds into a small
* negative number-of-100-nanosecond-increments.
*/
delta = pletohll(&hdr.hdr_2_x.ts_delta)*10;
/*
* OK, it's now a signed value in 100-nanosecond
* units. Now convert it to nanosecond units.
*/
delta *= 100;
break;
}
secs = 0;
t = netmon->start_nsecs + delta;
while (t < 0) {
/*
* Propagate a borrow into the seconds.
* The seconds is a time_t, and can be < 0
* (unlikely, as Windows didn't exist before
* January 1, 1970, 00:00:00 UTC), while the
* nanoseconds should be positive, as in
* "nanoseconds since the instant of time
* represented by the seconds".
*
* We do not want t to be negative, as, according
* to the C90 standard, "if either operand [of /
* or %] is negative, whether the result of the
* / operator is the largest integer less than or
* equal to the algebraic quotient or the smallest
* greater than or equal to the algebraic quotient
* is implementation-defined, as is the sign of
* the result of the % operator", and we want
* the result of the division and remainder
* operations to be the same on all platforms.
*/
t += 1000000000;
secs--;
}
secs += (time_t)(t/1000000000);
nsecs = (guint32)(t%1000000000);
wth->phdr.presence_flags = WTAP_HAS_TS|WTAP_HAS_CAP_LEN;
wth->phdr.ts.secs = netmon->start_secs + secs;
wth->phdr.ts.nsecs = nsecs;
wth->phdr.caplen = packet_size;
wth->phdr.len = orig_size;
/*
* For version 2.1 and later, there's additional information
* after the frame data.
*/
trlr_size = (int)netmon_trailer_size(netmon);
if (trlr_size != 0) {
/*
* I haz a trailer.
*/
wth->phdr.pkt_encap = netmon_read_rec_trailer(wth->fh,
trlr_size, err, err_info);
if (wth->phdr.pkt_encap == -1)
return FALSE; /* error */
wth->data_offset += trlr_size;
if (wth->phdr.pkt_encap == 0)
goto again;
netmon_set_pseudo_header_info(wth->phdr.pkt_encap,
&wth->pseudo_header, data_ptr, packet_size);
} else {
netmon_set_pseudo_header_info(wth->file_encap,
&wth->pseudo_header, data_ptr, packet_size);
}
return TRUE;
}
