Keep in the "wtap" structure the current offset into the file being

read, and maintain it ourselves as we read through the file, rather than
calling "ftell()" for every packet we read - "ftell()" may involve an
"lseek()" call, which could add a noticeable CPU overhead when reading a
large file.

git-svn-id: http://anonsvn.wireshark.org/wireshark/trunk@596 f5534014-38df-0310-8fa8-9805f1628bb7

diff --git a/wiretap/file.c b/wiretap/file.c
index 3e75cf1215347160d250518d7312ba4adb95fbc5..1a193a6602229a06114c422b19a08bcb2e4490f0 100644 (file)
--- a/wiretap/file.c
+++ b/wiretap/file.c
@@ -1,6 +1,6 @@
 /* file.c
  *
- * $Id: file.c,v 1.18 1999/08/22 02:29:38 guy Exp $
+ * $Id: file.c,v 1.19 1999/08/28 01:19:43 guy Exp $
  *
  * Wiretap Library
  * Copyright (c) 1998 by Gilbert Ramirez <gram@verdict.uthscsa.edu>
@@ -105,6 +105,7 @@ wtap* wtap_open_offline(const char *filename, int *err)
 
        /* initialization */
        wth->file_encap = WTAP_ENCAP_UNKNOWN;
+       wth->data_offset = 0;
 
        /* Try all file types */
        for (i = 0; i < N_FILE_TYPES; i++) {

diff --git a/wiretap/iptrace.c b/wiretap/iptrace.c
index 5b3652dc8638a237584e6efd03d966e7bd0da5c8..2d6ac594223b3e3bebd592ba34a5faef322339c3 100644 (file)
--- a/wiretap/iptrace.c
+++ b/wiretap/iptrace.c
@@ -1,6 +1,6 @@
 /* iptrace.c
  *
- * $Id: iptrace.c,v 1.9 1999/08/24 03:19:34 guy Exp $
+ * $Id: iptrace.c,v 1.10 1999/08/28 01:19:43 guy Exp $
  *
  * Wiretap Library
  * Copyright (c) 1998 by Gilbert Ramirez <gram@verdict.uthscsa.edu>
@@ -39,6 +39,7 @@ int iptrace_open(wtap *wth, int *err)
        char name[12];
 
        fseek(wth->fh, 0, SEEK_SET);
+       wth->data_offset = 0;
        errno = WTAP_ERR_CANT_READ;
        bytes_read = fread(name, 1, 11, wth->fh);
        if (bytes_read != 11) {
@@ -48,6 +49,7 @@ int iptrace_open(wtap *wth, int *err)
                }
                return 0;
        }
+       wth->data_offset += 11;
        name[11] = 0;
        if (strcmp(name, "iptrace 2.0") != 0) {
                return 0;
@@ -81,12 +83,13 @@ static int iptrace_read(wtap *wth, int *err)
                }
                return 0;
        }
+       wth->data_offset += 40;
 
        packet_size = pntohs(&header[2]) - 32;
 
        /* Read the packet data */
        buffer_assure_space(wth->frame_buffer, packet_size);
-       data_offset = ftell(wth->fh);
+       data_offset = wth->data_offset;
        errno = WTAP_ERR_CANT_READ;
        bytes_read = fread(buffer_start_ptr(wth->frame_buffer), 1,
                packet_size, wth->fh);
@@ -98,6 +101,7 @@ static int iptrace_read(wtap *wth, int *err)
                        *err = WTAP_ERR_SHORT_READ;
                return -1;
        }
+       wth->data_offset += packet_size;
 
        wth->phdr.len = packet_size;
        wth->phdr.caplen = packet_size;

diff --git a/wiretap/lanalyzer.c b/wiretap/lanalyzer.c
index b28cfa1444b0fa7120f10a9b0ff2a8720b320d94..e85705de7d588cd90ee786ec7dcf55ab71b666fd 100644 (file)
--- a/wiretap/lanalyzer.c
+++ b/wiretap/lanalyzer.c
@@ -1,6 +1,6 @@
 /* lanalyzer.c
  *
- * $Id: lanalyzer.c,v 1.13 1999/08/22 02:29:40 guy Exp $
+ * $Id: lanalyzer.c,v 1.14 1999/08/28 01:19:43 guy Exp $
  *
  * Wiretap Library
  * Copyright (c) 1998 by Gilbert Ramirez <gram@verdict.uthscsa.edu>
@@ -61,6 +61,7 @@ int lanalyzer_open(wtap *wth, int *err)
        struct tm tm;
 
        fseek(wth->fh, 0, SEEK_SET);
+       wth->data_offset = 0;
        errno = WTAP_ERR_CANT_READ;
        bytes_read = fread(LE_record_type, 1, 2, wth->fh);
        bytes_read += fread(LE_record_length, 1, 2, wth->fh);
@@ -71,6 +72,7 @@ int lanalyzer_open(wtap *wth, int *err)
                }
                return 0;
        }
+       wth->data_offset += 4;
        record_type = pletohs(LE_record_type);
        record_length = pletohs(LE_record_length); /* make sure to do this for while() loop */
 
@@ -89,6 +91,7 @@ int lanalyzer_open(wtap *wth, int *err)
        /* Read records until we find the start of packets */
        while (1) {
                fseek(wth->fh, record_length, SEEK_CUR);
+               wth->data_offset += record_length;
                errno = WTAP_ERR_CANT_READ;
                bytes_read = fread(LE_record_type, 1, 2, wth->fh);
                bytes_read += fread(LE_record_length, 1, 2, wth->fh);
@@ -101,6 +104,7 @@ int lanalyzer_open(wtap *wth, int *err)
                        g_free(wth->capture.lanalyzer);
                        return 0;
                }
+               wth->data_offset += 4;
 
                record_type = pletohs(LE_record_type);
                record_length = pletohs(LE_record_length);
@@ -121,6 +125,7 @@ int lanalyzer_open(wtap *wth, int *err)
                                        g_free(wth->capture.lanalyzer);
                                        return 0;
                                }
+                               wth->data_offset += sizeof summary;
 
                                /* Assume that the date of the creation of the trace file
                                 * is the same date of the trace. Lanalyzer doesn't
@@ -176,6 +181,7 @@ int lanalyzer_open(wtap *wth, int *err)
                                /* Go back header number ob ytes so that lanalyzer_read
                                 * can read this header */
                                fseek(wth->fh, -bytes_read, SEEK_CUR);
+                               wth->data_offset -= bytes_read;
                                return 1;
 
                        default:
@@ -217,6 +223,7 @@ static int lanalyzer_read(wtap *wth, int *err)
                }
                return 0;
        }
+       wth->data_offset += 2;
        bytes_read = fread(LE_record_length, 1, 2, wth->fh);
        if (bytes_read != 2) {
                if (ferror(wth->fh))
@@ -225,6 +232,7 @@ static int lanalyzer_read(wtap *wth, int *err)
                        *err = WTAP_ERR_SHORT_READ;
                return -1;
        }
+       wth->data_offset += 2;
 
        record_type = pletohs(LE_record_type);
        record_length = pletohs(LE_record_length);
@@ -252,10 +260,11 @@ static int lanalyzer_read(wtap *wth, int *err)
                        *err = WTAP_ERR_SHORT_READ;
                return -1;
        }
+       wth->data_offset += DESCRIPTOR_LEN;
 
        /* Read the packet data */
        buffer_assure_space(wth->frame_buffer, packet_size);
-       data_offset = ftell(wth->fh);
+       data_offset = wth->data_offset;
        errno = WTAP_ERR_CANT_READ;
        bytes_read = fread(buffer_start_ptr(wth->frame_buffer), 1,
                packet_size, wth->fh);
@@ -267,6 +276,7 @@ static int lanalyzer_read(wtap *wth, int *err)
                        *err = WTAP_ERR_SHORT_READ;
                return -1;
        }
+       wth->data_offset += packet_size;
 
        true_size = pletohs(&descriptor[4]);
        time_low = pletohs(&descriptor[8]);

diff --git a/wiretap/libpcap.c b/wiretap/libpcap.c
index 50a1689c417aa7708432ec9567146648f7c8ecd0..ccd62838e2f36bb08d080a04b19d5c7ea28695a1 100644 (file)
--- a/wiretap/libpcap.c
+++ b/wiretap/libpcap.c
@@ -1,6 +1,6 @@
 /* libpcap.c
  *
- * $Id: libpcap.c,v 1.15 1999/08/24 03:19:34 guy Exp $
+ * $Id: libpcap.c,v 1.16 1999/08/28 01:19:44 guy Exp $
  *
  * Wiretap Library
  * Copyright (c) 1998 by Gilbert Ramirez <gram@verdict.uthscsa.edu>
@@ -147,6 +147,7 @@ int libpcap_open(wtap *wth, int *err)
 
        /* Read in the number that should be at the start of a "libpcap" file */
        fseek(wth->fh, 0, SEEK_SET);
+       wth->data_offset = 0;
        errno = WTAP_ERR_CANT_READ;
        bytes_read = fread(&magic, 1, sizeof magic, wth->fh);
        if (bytes_read != sizeof magic) {
@@ -156,6 +157,7 @@ int libpcap_open(wtap *wth, int *err)
                }
                return 0;
        }
+       wth->data_offset += sizeof magic;
 
        if (magic == PCAP_SWAPPED_MAGIC) {
                /* Host that wrote it has a byte order opposite to ours. */
@@ -176,6 +178,7 @@ int libpcap_open(wtap *wth, int *err)
                }
                return 0;
        }
+       wth->data_offset += sizeof hdr;
 
        if (byte_swapped) {
                /* Byte-swap the header fields about which we care. */
@@ -233,6 +236,7 @@ static int libpcap_read(wtap *wth, int *err)
                }
                return 0;
        }
+       wth->data_offset += sizeof hdr;
 
        if (wth->capture.pcap->byte_swapped) {
                /* Byte-swap the record header fields. */
@@ -274,7 +278,7 @@ static int libpcap_read(wtap *wth, int *err)
        }
 
        buffer_assure_space(wth->frame_buffer, packet_size);
-       data_offset = ftell(wth->fh);
+       data_offset = wth->data_offset;
        errno = WTAP_ERR_CANT_READ;
        bytes_read = fread(buffer_start_ptr(wth->frame_buffer), 1,
                        packet_size, wth->fh);
@@ -286,6 +290,7 @@ static int libpcap_read(wtap *wth, int *err)
                        *err = WTAP_ERR_SHORT_READ;
                return -1;
        }
+       wth->data_offset += packet_size;
 
        wth->phdr.ts.tv_sec = hdr.ts_sec;
        wth->phdr.ts.tv_usec = hdr.ts_usec;

diff --git a/wiretap/netmon.c b/wiretap/netmon.c
index 57c967f6de1858d710aa38da6d9caa3874dbe087..b22428298131111ff1a9c660a2c7401a3c3a319e 100644 (file)
--- a/wiretap/netmon.c
+++ b/wiretap/netmon.c
@@ -1,6 +1,6 @@
 /* netmon.c
  *
- * $Id: netmon.c,v 1.12 1999/08/24 03:19:33 guy Exp $
+ * $Id: netmon.c,v 1.13 1999/08/28 01:19:44 guy Exp $
  *
  * Wiretap Library
  * Copyright (c) 1998 by Gilbert Ramirez <gram@verdict.uthscsa.edu>
@@ -214,6 +214,7 @@ int netmon_open(wtap *wth, int *err)
 
        /* Seek to the beginning of the data records. */
        fseek(wth->fh, CAPTUREFILE_HEADER_SIZE, SEEK_SET);
+       wth->data_offset = CAPTUREFILE_HEADER_SIZE;
 
        return 1;
 }
@@ -234,13 +235,11 @@ static int netmon_read(wtap *wth, int *err)
        double  t;
 
        /* Have we reached the end of the packet data? */
-       data_offset = ftell(wth->fh);
-       if (data_offset >= wth->capture.netmon->end_offset) {
+       if (wth->data_offset >= wth->capture.netmon->end_offset) {
                /* Yes. */
                return 0;
        }
        /* Read record header. */
-       /* Read record header. */
        switch (wth->capture.netmon->version_major) {
 
        case 1:
@@ -264,7 +263,7 @@ static int netmon_read(wtap *wth, int *err)
                }
                return 0;
        }
-       data_offset += hdr_size;
+       wth->data_offset += hdr_size;
 
        switch (wth->capture.netmon->version_major) {
 
@@ -287,6 +286,7 @@ static int netmon_read(wtap *wth, int *err)
                return -1;
        }
        buffer_assure_space(wth->frame_buffer, packet_size);
+       data_offset = wth->data_offset;
        errno = WTAP_ERR_CANT_READ;
        bytes_read = fread(buffer_start_ptr(wth->frame_buffer), 1,
                        packet_size, wth->fh);
@@ -298,6 +298,7 @@ static int netmon_read(wtap *wth, int *err)
                        *err = WTAP_ERR_SHORT_READ;
                return -1;
        }
+       wth->data_offset += packet_size;
 
        t = (double)wth->capture.netmon->start_usecs;
        switch (wth->capture.netmon->version_major) {

diff --git a/wiretap/netxray.c b/wiretap/netxray.c
index 673c229c4eb53fd84ff54f7195bf47d89c2326a6..c87ad3d3cf4ed5a8e8566213a0e587fd5e890002 100644 (file)
--- a/wiretap/netxray.c
+++ b/wiretap/netxray.c
@@ -1,6 +1,6 @@
 /* netxray.c
  *
- * $Id: netxray.c,v 1.12 1999/08/24 03:19:33 guy Exp $
+ * $Id: netxray.c,v 1.13 1999/08/28 01:19:44 guy Exp $
  *
  * Wiretap Library
  * Copyright (c) 1998 by Gilbert Ramirez <gram@verdict.uthscsa.edu>
@@ -116,6 +116,7 @@ int netxray_open(wtap *wth, int *err)
        /* Read in the string that should be at the start of a NetXRay
         * file */
        fseek(wth->fh, 0, SEEK_SET);
+       wth->data_offset = 0;
        errno = WTAP_ERR_CANT_READ;
        bytes_read = fread(magic, 1, sizeof magic, wth->fh);
        if (bytes_read != sizeof magic) {
@@ -125,6 +126,7 @@ int netxray_open(wtap *wth, int *err)
                }
                return 0;
        }
+       wth->data_offset += sizeof magic;
 
        if (memcmp(magic, netxray_magic, sizeof netxray_magic) != 0) {
                return 0;
@@ -140,6 +142,7 @@ int netxray_open(wtap *wth, int *err)
                }
                return 0;
        }
+       wth->data_offset += sizeof hdr;
 
        /* It appears that version 1.1 files (as produced by Windows
         * Sniffer Pro 2.0.01) have the time stamp in microseconds,
@@ -199,6 +202,7 @@ int netxray_open(wtap *wth, int *err)
 
        /* Seek to the beginning of the data records. */
        fseek(wth->fh, pletohl(&hdr.start_offset), SEEK_SET);
+       wth->data_offset = pletohl(&hdr.start_offset);
 
        return 1;
 }
@@ -218,8 +222,7 @@ static int netxray_read(wtap *wth, int *err)
 
 reread:
        /* Have we reached the end of the packet data? */
-       data_offset = ftell(wth->fh);
-       if (data_offset == wth->capture.netxray->end_offset) {
+       if (wth->data_offset == wth->capture.netxray->end_offset) {
                /* Yes. */
                return 0;
        }
@@ -251,16 +254,18 @@ reread:
                        /* Yes.  Remember that we did. */
                        wth->capture.netxray->wrapped = 1;
                        fseek(wth->fh, CAPTUREFILE_HEADER_SIZE, SEEK_SET);
+                       wth->data_offset = CAPTUREFILE_HEADER_SIZE;
                        goto reread;
                }
 
                /* We've already wrapped - don't wrap again. */
                return 0;
        }
-       data_offset += hdr_size;
+       wth->data_offset += hdr_size;
 
        packet_size = pletohs(&hdr.hdr_1_x.incl_len);
        buffer_assure_space(wth->frame_buffer, packet_size);
+       data_offset = wth->data_offset;
        errno = WTAP_ERR_CANT_READ;
        bytes_read = fread(buffer_start_ptr(wth->frame_buffer), 1,
                        packet_size, wth->fh);
@@ -272,6 +277,7 @@ reread:
                        *err = WTAP_ERR_SHORT_READ;
                return -1;
        }
+       wth->data_offset += packet_size;
 
        t = (double)pletohl(&hdr.hdr_1_x.timelo)
            + (double)pletohl(&hdr.hdr_1_x.timehi)*4294967296.0;

diff --git a/wiretap/ngsniffer.c b/wiretap/ngsniffer.c
index c2ed78d151b6606f56c13ca47c86eaaf8761ef9e..c7ab2fcb2bda4ce1729a0a644947212997c3ea59 100644 (file)
--- a/wiretap/ngsniffer.c
+++ b/wiretap/ngsniffer.c
@@ -1,6 +1,6 @@
 /* ngsniffer.c
  *
- * $Id: ngsniffer.c,v 1.20 1999/08/24 03:19:32 guy Exp $
+ * $Id: ngsniffer.c,v 1.21 1999/08/28 01:19:44 guy Exp $
  *
  * Wiretap Library
  * Copyright (c) 1998 by Gilbert Ramirez <gram@verdict.uthscsa.edu>
@@ -269,6 +269,7 @@ int ngsniffer_open(wtap *wth, int *err)
 
        /* Read in the string that should be at the start of a Sniffer file */
        fseek(wth->fh, 0, SEEK_SET);
+       wth->data_offset = 0;
        errno = WTAP_ERR_CANT_READ;
        bytes_read = fread(magic, 1, 17, wth->fh);
        if (bytes_read != 17) {
@@ -278,6 +279,7 @@ int ngsniffer_open(wtap *wth, int *err)
                }
                return 0;
        }
+       wth->data_offset += 17;
 
        magic[17] = 0;
 
@@ -299,6 +301,7 @@ int ngsniffer_open(wtap *wth, int *err)
                }
                return 0;
        }
+       wth->data_offset += 6;
 
        type = pletohs(record_type);
        length = pletohs(record_length);
@@ -318,6 +321,7 @@ int ngsniffer_open(wtap *wth, int *err)
                }
                return 0;
        }
+       wth->data_offset += sizeof version;
 
        /* Make sure this is an uncompressed Sniffer file */
        if (version.format != 1) {
@@ -416,6 +420,7 @@ static int ngsniffer_read(wtap *wth, int *err)
                        }
                        return 0;
                }
+               wth->data_offset += 2;
                errno = WTAP_ERR_CANT_READ;
                bytes_read = fread(record_length, 1, 4, wth->fh);
                if (bytes_read != 4) {
@@ -425,6 +430,7 @@ static int ngsniffer_read(wtap *wth, int *err)
                                *err = WTAP_ERR_SHORT_READ;
                        return -1;
                }
+               wth->data_offset += 4;
 
                type = pletohs(record_type);
                length = pletohs(record_length);
@@ -452,6 +458,7 @@ static int ngsniffer_read(wtap *wth, int *err)
                                        *err = WTAP_ERR_SHORT_READ;
                                return -1;
                        }
+                       wth->data_offset += sizeof frame2;
                        time_low = pletohs(&frame2.time_low);
                        time_med = pletohs(&frame2.time_med);
                        time_high = pletohs(&frame2.time_high);
@@ -488,6 +495,7 @@ static int ngsniffer_read(wtap *wth, int *err)
                                        *err = WTAP_ERR_SHORT_READ;
                                return -1;
                        }
+                       wth->data_offset += sizeof frame4;
                        time_low = pletohs(&frame4.time_low);
                        time_med = pletohs(&frame4.time_med);
                        time_high = frame4.time_high;
@@ -539,6 +547,7 @@ static int ngsniffer_read(wtap *wth, int *err)
                 * portion, and keep looping.
                 */
                fseek(wth->fh, length, SEEK_CUR);
+               wth->data_offset += length;
        }
 
 found:
@@ -549,7 +558,7 @@ found:
         * Read the packet data.
         */
        buffer_assure_space(wth->frame_buffer, length);
-       data_offset = ftell(wth->fh);
+       data_offset = wth->data_offset;
        errno = WTAP_ERR_CANT_READ;
        bytes_read = fread(buffer_start_ptr(wth->frame_buffer), 1,
                        length, wth->fh);
@@ -561,6 +570,7 @@ found:
                        *err = WTAP_ERR_SHORT_READ;
                return -1;
        }
+       wth->data_offset += length;
 
        t = t/1000000.0 * wth->capture.ngsniffer->timeunit; /* t = # of secs */
        t += wth->capture.ngsniffer->start;

diff --git a/wiretap/radcom.c b/wiretap/radcom.c
index 0459fac033dae12d5b0b0049d9ffe6b00eb94981..4db683a1f665fdd24e7c15bc5033d916efb317e5 100644 (file)
--- a/wiretap/radcom.c
+++ b/wiretap/radcom.c
@@ -165,10 +165,13 @@ int radcom_open(wtap *wth, int *err)
                }
        }*/
 
-       if (wth->file_encap == WTAP_ENCAP_ETHERNET)
+       if (wth->file_encap == WTAP_ENCAP_ETHERNET) {
                fseek(wth->fh, 294, SEEK_CUR);
-       else if (wth->file_encap == WTAP_ENCAP_LAPB)
+               wth->data_offset = 294;
+       } else if (wth->file_encap == WTAP_ENCAP_LAPB) {
                fseek(wth->fh, 297, SEEK_CUR);
+               wth->data_offset = 297;
+       }
 
        return 1;
 
@@ -193,6 +196,7 @@ static int radcom_read(wtap *wth, int *err)
        char dce;
 
        fseek(wth->fh, 4, SEEK_CUR);
+       wth->data_offset += 4;
 
        /*
         * Read the frame size
@@ -210,6 +214,7 @@ static int radcom_read(wtap *wth, int *err)
                }
                return 0;
        }
+       wth->data_offset += 2;
 
        if (wth->file_encap == WTAP_ENCAP_LAPB)
                length -= 2; /* FCS */
@@ -218,6 +223,7 @@ static int radcom_read(wtap *wth, int *err)
        wth->phdr.caplen = length;
 
        fseek(wth->fh, 5, SEEK_CUR);
+       wth->data_offset += 5;
        errno = WTAP_ERR_CANT_READ;
        bytes_read = fread(&date, 1, sizeof(struct frame_date), wth->fh);
        if (bytes_read != sizeof(struct frame_date)) {
@@ -227,6 +233,7 @@ static int radcom_read(wtap *wth, int *err)
                        *err = WTAP_ERR_SHORT_READ;
                return -1;
        }
+       wth->data_offset += sizeof(struct frame_date);
 
        tm.tm_year = date.year-1900;
        tm.tm_mon = date.month-1;
@@ -239,6 +246,7 @@ static int radcom_read(wtap *wth, int *err)
        wth->phdr.ts.tv_usec = date.usec;
 
        fseek(wth->fh, 6, SEEK_CUR);
+       wth->data_offset += 6;
        errno = WTAP_ERR_CANT_READ;
        bytes_read = fread(&dce, 1, 1, wth->fh);
        if (bytes_read != 1) {
@@ -248,6 +256,7 @@ static int radcom_read(wtap *wth, int *err)
                        *err = WTAP_ERR_SHORT_READ;
                return -1;
        }
+       wth->data_offset += 1;
        wth->phdr.pseudo_header.x25.flags = (dce & 0x1) ? 0x00 : 0x80;
 
        fseek(wth->fh, 9, SEEK_CUR);
@@ -256,7 +265,7 @@ static int radcom_read(wtap *wth, int *err)
         * Read the packet data.
         */
        buffer_assure_space(wth->frame_buffer, length);
-       data_offset = ftell(wth->fh);
+       data_offset = wth->data_offset;
        errno = WTAP_ERR_CANT_READ;
        bytes_read = fread(buffer_start_ptr(wth->frame_buffer), 1,
                        length, wth->fh);
@@ -268,11 +277,14 @@ static int radcom_read(wtap *wth, int *err)
                        *err = WTAP_ERR_SHORT_READ;
                return -1;
        }
+       wth->data_offset += length;
 
        wth->phdr.pkt_encap = wth->file_encap;
 
-       if (wth->file_encap == WTAP_ENCAP_LAPB)
+       if (wth->file_encap == WTAP_ENCAP_LAPB) {
                fseek(wth->fh, 2, SEEK_CUR); /* FCS */
+               wth->data_offset += 2;
+       }
 
        return data_offset;
 }

diff --git a/wiretap/snoop.c b/wiretap/snoop.c
index d99ad456c71f96033a90fd56e8e7023eac00384d..9b854146a333889386ec8deaa1ef179df9d67f10 100644 (file)
--- a/wiretap/snoop.c
+++ b/wiretap/snoop.c
@@ -1,6 +1,6 @@
 /* snoop.c
  *
- * $Id: snoop.c,v 1.8 1999/08/24 03:19:32 guy Exp $
+ * $Id: snoop.c,v 1.9 1999/08/28 01:19:45 guy Exp $
  *
  * Wiretap Library
  * Copyright (c) 1998 by Gilbert Ramirez <gram@verdict.uthscsa.edu>
@@ -77,6 +77,7 @@ int snoop_open(wtap *wth, int *err)
 
        /* Read in the string that should be at the start of a "snoop" file */
        fseek(wth->fh, 0, SEEK_SET);
+       wth->data_offset = 0;
        errno = WTAP_ERR_CANT_READ;
        bytes_read = fread(magic, 1, sizeof magic, wth->fh);
        if (bytes_read != sizeof magic) {
@@ -86,6 +87,7 @@ int snoop_open(wtap *wth, int *err)
                }
                return 0;
        }
+       wth->data_offset += sizeof magic;
 
        if (memcmp(magic, snoop_magic, sizeof snoop_magic) != 0) {
                return 0;
@@ -101,6 +103,7 @@ int snoop_open(wtap *wth, int *err)
                }
                return 0;
        }
+       wth->data_offset += sizeof hdr;
 
        hdr.version = ntohl(hdr.version);
        if (hdr.version != 2) {
@@ -148,6 +151,7 @@ static int snoop_read(wtap *wth, int *err)
                }
                return 0;
        }
+       wth->data_offset += sizeof hdr;
 
        packet_size = ntohl(hdr.incl_len);
        if (packet_size > WTAP_MAX_PACKET_SIZE) {
@@ -161,7 +165,7 @@ static int snoop_read(wtap *wth, int *err)
                return -1;
        }
        buffer_assure_space(wth->frame_buffer, packet_size);
-       data_offset = ftell(wth->fh);
+       data_offset = wth->data_offset;
        errno = WTAP_ERR_CANT_READ;
        bytes_read = fread(buffer_start_ptr(wth->frame_buffer), 1,
                        packet_size, wth->fh);
@@ -173,6 +177,7 @@ static int snoop_read(wtap *wth, int *err)
                        *err = WTAP_ERR_SHORT_READ;
                return -1;
        }
+       wth->data_offset += packet_size;
 
        wth->phdr.ts.tv_sec = ntohl(hdr.ts_sec);
        wth->phdr.ts.tv_usec = ntohl(hdr.ts_usec);
@@ -183,6 +188,7 @@ static int snoop_read(wtap *wth, int *err)
        /* Skip over the padding. */
        fseek(wth->fh, ntohl(hdr.rec_len) - (sizeof hdr + packet_size),
            SEEK_CUR);
+       wth->data_offset += ntohl(hdr.rec_len) - (sizeof hdr + packet_size);
 
        return data_offset;
 }

diff --git a/wiretap/wtap.h b/wiretap/wtap.h
index 93d791b2b06c8eb8d252c3756b6f10bd15b0802d..4b1eaa733215c5e2c2b95c562a6e9447ce3aabeb 100644 (file)
--- a/wiretap/wtap.h
+++ b/wiretap/wtap.h
@@ -1,6 +1,6 @@
 /* wtap.h
  *
- * $Id: wtap.h,v 1.34 1999/08/24 03:19:34 guy Exp $
+ * $Id: wtap.h,v 1.35 1999/08/28 01:19:45 guy Exp $
  *
  * Wiretap Library
  * Copyright (c) 1998 by Gilbert Ramirez <gram@verdict.uthscsa.edu>
@@ -261,6 +261,8 @@ typedef struct wtap {
        struct Buffer           *frame_buffer;
        struct wtap_pkthdr      phdr;
 
+       long                    data_offset;
+
        union {
                libpcap_t               *pcap;
                lanalyzer_t             *lanalyzer;