diff options
| -rw-r--r-- | pcap-linux.c | 35 |
1 files changed, 34 insertions, 1 deletions
diff --git a/pcap-linux.c b/pcap-linux.c index 912847ab..4ac1bcc4 100644 --- a/pcap-linux.c +++ b/pcap-linux.c @@ -1864,9 +1864,18 @@ pcap_read_packet(pcap_t *handle, pcap_handler callback, u_char *userdata) if (len < (unsigned int) handlep->vlan_offset) break; + /* + * Move everything in the header, except the + * type field, down VLAN_TAG_LEN bytes, to + * allow us to insert the VLAN tag between + * that stuff and the type field. + */ bp -= VLAN_TAG_LEN; memmove(bp, bp + VLAN_TAG_LEN, handlep->vlan_offset); + /* + * Now insert the tag. + */ tag = (struct vlan_tag *)(bp + handlep->vlan_offset); tag->vlan_tpid = htons(VLAN_TPID(aux, aux)); tag->vlan_tci = htons(aux->tp_vlan_tci); @@ -1876,6 +1885,10 @@ pcap_read_packet(pcap_t *handle, pcap_handler callback, u_char *userdata) aux_data.vlan_tag = htons(aux->tp_vlan_tci) & 0x0fff; aux_data.vlan_tag_present = (aux->tp_status & TP_STATUS_VLAN_VALID); #endif + + /* + * Add the tag to the packet lengths. + */ packet_len += VLAN_TAG_LEN; } } @@ -3570,15 +3583,24 @@ activate_new(pcap_t *handle) /* * Set the offset at which to insert VLAN tags. + * That should be the offset of the type field. */ switch (handle->linktype) { case DLT_EN10MB: + /* + * The type field is after the destination and source + * MAC address. + */ handlep->vlan_offset = 2 * ETH_ALEN; break; case DLT_LINUX_SLL: - handlep->vlan_offset = 14; + /* + * The type field is in the last 2 bytes of the + * DLT_LINUX_SLL header. + */ + handlep->vlan_offset = SLL_HDR_LEN - 2; break; default: @@ -4663,13 +4685,24 @@ static int pcap_handle_packet_mmap( { struct vlan_tag *tag; + /* + * Move everything in the header, except the type field, + * down VLAN_TAG_LEN bytes, to allow us to insert the + * VLAN tag between that stuff and the type field. + */ bp -= VLAN_TAG_LEN; memmove(bp, bp + VLAN_TAG_LEN, handlep->vlan_offset); + /* + * Now insert the tag. + */ tag = (struct vlan_tag *)(bp + handlep->vlan_offset); tag->vlan_tpid = htons(tp_vlan_tpid); tag->vlan_tci = htons(tp_vlan_tci); + /* + * Add the tag to the packet lengths. + */ pcaphdr.caplen += VLAN_TAG_LEN; pcaphdr.len += VLAN_TAG_LEN; } |