Allow bigger snapshot lengths for D-Bus captures.

Use WTAP_MAX_PACKET_SIZE_STANDARD, set to 256KB, for everything except
for D-Bus captures.  Use WTAP_MAX_PACKET_SIZE_DBUS, set to 128MB, for
them, because that's the largest possible D-Bus message size.  See

	https://bugs.freedesktop.org/show_bug.cgi?id=100220

for an example of the problems caused by limiting the snapshot length to
256KB for D-Bus.

Have a snapshot length of 0 in a capture_file structure mean "there is
no snapshot length for the file"; we don't need the has_snap field in
that case, a value of 0 mean "no, we don't have a snapshot length".

In dumpcap, start out with a pipe buffer size of 2KB, and grow it as
necessary.  When checking for a too-big packet from a pipe, check
against the appropriate maximum - 128MB for DLT_DBUS, 256KB for
everything else.

Change-Id: Ib2ce7a0cf37b971fbc0318024fd011e18add8b20
Reviewed-on: https://code.wireshark.org/review/21952
Petri-Dish: Guy Harris <guy@alum.mit.edu>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Guy Harris <guy@alum.mit.edu>

1 files changed, 6 insertions, 6 deletions

diff --git a/wiretap/vwr.c b/wiretap/vwr.c
index 015a7a0205..2b04757a79 100644
--- a/wiretap/vwr.c
+++ b/wiretap/vwr.c
@@ -1275,7 +1275,7 @@ static gboolean vwr_read_s1_W_rec(vwr_t *vwr, struct wtap_pkthdr *phdr,
      *
      * The maximum value of actual_octets is 8191, which, even after
      * adding the lengths of the metadata headers, is less than
-     * WTAP_MAX_PACKET_SIZE will ever be, so we don't need to check it.
+     * WTAP_MAX_PACKET_SIZE_STANDARD will ever be, so we don't need to check it.
      */
     phdr->len = STATS_COMMON_FIELDS_LEN + EXT_WLAN_FIELDS_LEN + actual_octets;
     phdr->caplen = STATS_COMMON_FIELDS_LEN + EXT_WLAN_FIELDS_LEN + actual_octets;
@@ -1688,7 +1688,7 @@ static gboolean vwr_read_s2_W_rec(vwr_t *vwr, struct wtap_pkthdr *phdr,
      *
      * The maximum value of actual_octets is 8191, which, even after
      * adding the lengths of the metadata headers, is less than
-     * WTAP_MAX_PACKET_SIZE will ever be, so we don't need to check it.
+     * WTAP_MAX_PACKET_SIZE_STANDARD will ever be, so we don't need to check it.
      */
     phdr->len = STATS_COMMON_FIELDS_LEN + EXT_WLAN_FIELDS_LEN + actual_octets;
     phdr->caplen = STATS_COMMON_FIELDS_LEN + EXT_WLAN_FIELDS_LEN + actual_octets;
@@ -1868,7 +1868,7 @@ static gboolean vwr_read_s3_W_rec(vwr_t *vwr, struct wtap_pkthdr *phdr,
          *
          * We include the length of the metadata headers in the packet lengths.
          *
-         * OCTO_MODIFIED_RF_LEN + 1 is less than WTAP_MAX_PACKET_SIZE will
+         * OCTO_MODIFIED_RF_LEN + 1 is less than WTAP_MAX_PACKET_SIZE_STANDARD will
          * ever be, so we don't need to check it.
          */
         phdr->len = OCTO_MODIFIED_RF_LEN + 1;       /* 1st octet is reserved for detecting type of frame while displaying in wireshark */
@@ -2184,14 +2184,14 @@ static gboolean vwr_read_s3_W_rec(vwr_t *vwr, struct wtap_pkthdr *phdr,
             phdr->len = OCTO_TIMESTAMP_FIELDS_LEN + OCTO_LAYER1TO4_LEN + actual_octets;
             phdr->caplen = OCTO_TIMESTAMP_FIELDS_LEN + OCTO_LAYER1TO4_LEN + actual_octets;
         }
-        if (phdr->caplen > WTAP_MAX_PACKET_SIZE) {
+        if (phdr->caplen > WTAP_MAX_PACKET_SIZE_STANDARD) {
             /*
              * Probably a corrupt capture file; return an error,
              * so that our caller doesn't blow up trying to allocate
              * space for an immensely-large packet.
              */
             *err_info = g_strdup_printf("vwr: File has %u-byte packet, bigger than maximum of %u",
-                                        phdr->caplen, WTAP_MAX_PACKET_SIZE);
+                                        phdr->caplen, WTAP_MAX_PACKET_SIZE_STANDARD);
             *err = WTAP_ERR_BAD_FILE;
             return FALSE;
         }
@@ -2696,7 +2696,7 @@ static gboolean vwr_read_rec_data_ethernet(vwr_t *vwr, struct wtap_pkthdr *phdr,
      *
      * The maximum value of actual_octets is 65535, which, even after
      * adding the lengths of the metadata headers, is less than
-     * WTAP_MAX_PACKET_SIZE will ever be, so we don't need to check it.
+     * WTAP_MAX_PACKET_SIZE_STANDARD will ever be, so we don't need to check it.
      */
     phdr->len = STATS_COMMON_FIELDS_LEN + EXT_ETHERNET_FIELDS_LEN + actual_octets;
     phdr->caplen = STATS_COMMON_FIELDS_LEN + EXT_ETHERNET_FIELDS_LEN + actual_octets;