forked from osmocom/wireshark
Signed-off-by: Jesper Dangaard Brouer <hawk@comx.dk>
Reviewed-by: Martin Philip Topholm <mph@comx.dk> Implement packet loss detection in for MPEG2 Transport Streams Second Part of https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=3227 svn path=/trunk/; revision=27381
This commit is contained in:
Anders Broman
parent
48bf9f396e
commit
df6d3da586
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@ -38,6 +38,10 @@
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#include <epan/rtp_pt.h>
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#include "packet-frame.h"
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#include <epan/emem.h>
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#include <epan/conversation.h>
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#include <epan/expert.h>
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/* The MPEG2 TS packet size */
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#define MP2T_PACKET_SIZE 188
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#define MP2T_SYNC_BYTE 0x47
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@ -58,6 +62,7 @@ static int hf_mp2t_pid = -1;
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static int hf_mp2t_tsc = -1;
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static int hf_mp2t_afc = -1;
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static int hf_mp2t_cc = -1;
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static int hf_mp2t_cc_drop = -1;
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#define MP2T_SYNC_BYTE_MASK 0xFF000000
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#define MP2T_TEI_MASK 0x00800000
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@ -187,14 +192,267 @@ static const value_string mp2t_afc_vals[] = {
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{ 0, NULL }
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};
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/* Data structure used for detecting CC drops
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*
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* conversation
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* |
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* +-> mp2t_analysis_data
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* |
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* +-> pid_table (RB tree)
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* | |
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* | +-> pid_analysis_data (per pid)
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* | +-> pid_analysis_data
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* | +-> pid_analysis_data
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* |
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* +-> frame_table (RB tree)
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* |
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* +-> frame_analysis_data (only created if drop detected)
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* |
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* +-> ts_table (RB tree)
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* |
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* +-> pid_analysis_data (per TS subframe)
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* +-> pid_analysis_data
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* +-> pid_analysis_data
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*/
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typedef struct mp2t_analysis_data {
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/* This structure contains a tree containing data for the
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* individual pid's, this is only used when packets are
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* processed sequencially.
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*/
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emem_tree_t *pid_table;
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/* When detecting a CC drop, store that information for the
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* given frame. This info is needed, when clicking around in
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* wireshark, as the pid table data only makes sence during
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* sequencial processing. The flag pinfo->fd->flags.visited is
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* used to tell the difference.
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*
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*/
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emem_tree_t *frame_table;
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guint32 cc_drops; /* Number of detected CC losses per conv */
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} mp2t_analysis_data_t;
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typedef struct pid_analysis_data {
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guint16 pid;
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gint16 cc_prev; /* Previous CC number */
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} pid_analysis_data_t;
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typedef struct frame_analysis_data {
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/* As each frame has several pid's, thus need a pid data
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* structure per TS frame.
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*/
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emem_tree_t *ts_table;
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} frame_analysis_data_t;
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conversation_t *
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get_the_conversation(packet_info *pinfo)
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{
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conversation_t *conv = NULL;
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conv = find_conversation(pinfo->fd->num, &pinfo->src,
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&pinfo->dst, pinfo->ptype,
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pinfo->srcport, pinfo->destport, 0);
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if (conv == NULL) { /* Create a new conversation */
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conv = conversation_new(pinfo->fd->num, &pinfo->src,
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&pinfo->dst, pinfo->ptype,
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pinfo->srcport, pinfo->destport, 0);
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}
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return conv;
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}
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mp2t_analysis_data_t *
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init_mp2t_conversation_data()
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{
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mp2t_analysis_data_t *mp2t_data = NULL;
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mp2t_data = se_alloc0(sizeof(struct mp2t_analysis_data));
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mp2t_data->pid_table =
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se_tree_create_non_persistent(EMEM_TREE_TYPE_RED_BLACK,
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"mp2t_pid_table");
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mp2t_data->frame_table =
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se_tree_create_non_persistent(EMEM_TREE_TYPE_RED_BLACK,
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"mp2t_frame_table");
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mp2t_data->cc_drops = 0;
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return mp2t_data;
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}
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mp2t_analysis_data_t *
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get_mp2t_conversation_data(conversation_t *conv)
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{
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mp2t_analysis_data_t *mp2t_data = NULL;
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mp2t_data = conversation_get_proto_data(conv, proto_mp2t);
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if (!mp2t_data) {
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mp2t_data = init_mp2t_conversation_data();
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conversation_add_proto_data(conv, proto_mp2t, mp2t_data);
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}
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return mp2t_data;
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}
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frame_analysis_data_t *
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init_frame_analysis_data(mp2t_analysis_data_t *mp2t_data, packet_info *pinfo)
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{
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frame_analysis_data_t *frame_data = NULL;
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frame_data = se_alloc0(sizeof(struct frame_analysis_data));
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frame_data->ts_table =
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se_tree_create_non_persistent(EMEM_TREE_TYPE_RED_BLACK,
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"mp2t_frame_pid_table");
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/* Insert into mp2t tree */
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se_tree_insert32(mp2t_data->frame_table, pinfo->fd->num,
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(void *)frame_data);
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return frame_data;
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}
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frame_analysis_data_t *
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get_frame_analysis_data(mp2t_analysis_data_t *mp2t_data, packet_info *pinfo)
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{
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frame_analysis_data_t *frame_data = NULL;
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frame_data = se_tree_lookup32(mp2t_data->frame_table, pinfo->fd->num);
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return frame_data;
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}
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pid_analysis_data_t *
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get_pid_analysis(guint32 pid, conversation_t *conv)
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{
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pid_analysis_data_t *pid_data = NULL;
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mp2t_analysis_data_t *mp2t_data = NULL;
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mp2t_data = get_mp2t_conversation_data(conv);
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pid_data = se_tree_lookup32(mp2t_data->pid_table, pid);
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if (!pid_data) {
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pid_data = se_alloc0(sizeof(struct pid_analysis_data));
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pid_data->cc_prev = -1;
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pid_data->pid = pid;
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se_tree_insert32(mp2t_data->pid_table, pid, (void *)pid_data);
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}
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return pid_data;
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}
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#define KEY(pid, cc) ((pid << 4)|cc)
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void
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detect_cc_drops(tvbuff_t *tvb, proto_tree *tree, packet_info *pinfo,
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guint32 pid, gint32 cc_curr, conversation_t *conv)
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{
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gint32 cc_prev;
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pid_analysis_data_t *pid_data = NULL;
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pid_analysis_data_t *ts_data = NULL;
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mp2t_analysis_data_t *mp2t_data = NULL;
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frame_analysis_data_t *frame_data = NULL;
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proto_item *flags_item;
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guint32 detected_drop = 0;
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mp2t_data = get_mp2t_conversation_data(conv);
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/* The initial sequencial processing stage */
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if (!pinfo->fd->flags.visited) {
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/* This is the sequencial processing stage */
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pid_data = get_pid_analysis(pid, conv);
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cc_prev = pid_data->cc_prev;
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pid_data->cc_prev = cc_curr;
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/* Null packet always have a CC value equal 0 */
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if (pid == 0x1fff)
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return;
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/* Its allowed that (cc_prev == cc_curr) if adaptation field */
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if (cc_prev == cc_curr)
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return;
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/* Have not seen this pid before */
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if (cc_prev == -1)
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return;
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/* Detect if CC is not increasing by one all the time */
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if (cc_curr != ((cc_prev+1) & MP2T_CC_MASK)) {
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detected_drop = 1;
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mp2t_data->cc_drops++;
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}
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}
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/* Save the info about the dropped packet */
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if (detected_drop && !pinfo->fd->flags.visited) {
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/* Lookup frame data, contains TS pid data objects */
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frame_data = get_frame_analysis_data(mp2t_data, pinfo);
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if (!frame_data)
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frame_data = init_frame_analysis_data(mp2t_data, pinfo);
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/* Create and store a new TS frame pid_data object.
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This indicate that we have a drop
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*/
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ts_data = se_alloc0(sizeof(struct pid_analysis_data));
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ts_data->cc_prev = cc_prev;
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ts_data->pid = pid;
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se_tree_insert32(frame_data->ts_table, KEY(pid, cc_curr),
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(void *)ts_data);
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}
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/* See if we stored info about drops */
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if (pinfo->fd->flags.visited) {
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/* Lookup frame data, contains TS pid data objects */
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frame_data = get_frame_analysis_data(mp2t_data, pinfo);
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if (!frame_data)
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return; /* No stored frame data -> no drops*/
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else {
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ts_data = se_tree_lookup32(frame_data->ts_table,
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KEY(pid, cc_curr));
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if (ts_data)
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detected_drop = 1;
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}
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}
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/* Add info to the proto tree about drops */
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if (detected_drop) {
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flags_item =
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proto_tree_add_none_format(
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tree, hf_mp2t_cc_drop, tvb, 0, 0,
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"Detected missing CC frame before this"
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" (accumulated CC loss count:%d)",
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mp2t_data->cc_drops
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);
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PROTO_ITEM_SET_GENERATED(flags_item);
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expert_add_info_format(pinfo, flags_item, PI_MALFORMED,
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PI_ERROR, "Detected CC loss");
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}
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}
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static gint
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dissect_tsp( tvbuff_t *tvb, gint offset, packet_info *pinfo, proto_tree *tree )
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dissect_tsp(tvbuff_t *tvb, gint offset, packet_info *pinfo, proto_tree *tree,
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conversation_t *conv)
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{
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guint32 header;
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guint afc;
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gint start_offset = offset;
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gint payload_len;
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guint32 pid;
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guint32 cc;
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proto_item *ti = NULL;
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proto_item *hi = NULL;
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proto_tree *mp2t_tree = NULL;
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@ -206,8 +464,11 @@ dissect_tsp( tvbuff_t *tvb, gint offset, packet_info *pinfo, proto_tree *tree )
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header = tvb_get_ntohl(tvb, offset);
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proto_item_append_text(ti, " PID=0x%x CC=%d", (header & MP2T_PID_MASK) >> MP2T_PID_SHIFT, (header & MP2T_CC_MASK) >> MP2T_CC_SHIFT );
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pid = (header & MP2T_PID_MASK) >> MP2T_PID_SHIFT;
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cc = (header & MP2T_CC_MASK) >> MP2T_CC_SHIFT;
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proto_item_append_text(ti, " PID=0x%x CC=%d", pid, cc);
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detect_cc_drops(tvb, tree, pinfo, pid, cc, conv);
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hi = proto_tree_add_item( mp2t_tree, hf_mp2t_header, tvb, offset, 4, FALSE);
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mp2t_header_tree = proto_item_add_subtree( hi, ett_mp2t_header );
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@ -452,9 +713,11 @@ static void
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dissect_mp2t( tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree )
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{
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guint offset = 0;
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conversation_t *conv;
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conv = get_the_conversation(pinfo);
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while ( tvb_reported_length_remaining(tvb, offset) >= MP2T_PACKET_SIZE ) {
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offset = dissect_tsp( tvb, offset, pinfo, tree);
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offset = dissect_tsp(tvb, offset, pinfo, tree, conv);
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}
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}
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@ -517,6 +780,10 @@ proto_register_mp2t(void)
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"Continuity Counter", "mp2t.cc",
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FT_UINT32, BASE_DEC, NULL, MP2T_CC_MASK, NULL, HFILL
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} } ,
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{ &hf_mp2t_cc_drop, {
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"Continuity Counter Drops", "mp2t.cc.drop",
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FT_NONE, BASE_DEC, NULL, 0x0, NULL, HFILL
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} } ,
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{ &hf_mp2t_af, {
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"Adaption field", "mp2t.af",
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FT_NONE, BASE_HEX, NULL, 0, NULL, HFILL
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