mirror of https://github.com/FreeRDP/FreeRDP
proxy: prepare intercept mode for dynamic channels
This patch introduce the basic architecture to intercept content of dynamic channel. When a dynamic channel is in intercept mode, we accumulate and reassemble the current packet so that it can be passed for inspection.
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ff266e9575
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7041517ed6
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@ -36,24 +36,38 @@ typedef enum
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CHANNEL_OPENSTATE_CLOSED /*!< dynamic channel has been opened then closed */
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} PfDynChannelOpenStatus;
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typedef struct p_server_dynamic_channel_context pServerDynamicChannelContext;
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typedef struct DynChannelTrackerState DynChannelTrackerState;
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typedef PfChannelResult (*dynamic_channel_on_data_fn)(pServerContext* ps,
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pServerDynamicChannelContext* channel,
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BOOL isBackData, ChannelStateTracker* tracker,
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BOOL firstPacket, BOOL lastPacket);
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/** @brief tracker state for a drdynvc stream */
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typedef struct
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struct DynChannelTrackerState
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{
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UINT32 currentDataLength;
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UINT32 CurrentDataReceived;
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UINT32 CurrentDataFragments;
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} DynChannelTrackerState;
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wStream* currentPacket;
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dynamic_channel_on_data_fn dataCallback;
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};
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typedef struct p_server_dynamic_channel_context pServerDynamicChannelContext;
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typedef void (*channel_data_dtor_fn)(void** user_data);
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struct p_server_dynamic_channel_context
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{
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char* channel_name;
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UINT32 channel_id;
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char* channelName;
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UINT32 channelId;
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PfDynChannelOpenStatus openStatus;
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pf_utils_channel_mode channelMode;
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BOOL packetReassembly;
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DynChannelTrackerState backTracker;
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DynChannelTrackerState frontTracker;
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void* channelData;
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channel_data_dtor_fn channelDataDtor;
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};
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/** @brief context for the dynamic channel */
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@ -82,9 +96,9 @@ static pServerDynamicChannelContext* DynamicChannelContext_new(pServerContext* p
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return NULL;
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}
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ret->channel_id = id;
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ret->channel_name = _strdup(name);
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if (!ret->channel_name)
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ret->channelId = id;
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ret->channelName = _strdup(name);
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if (!ret->channelName)
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{
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PROXY_LOG_ERR(TAG, ps, "error allocating name in dynamic channel context '%s'", name);
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free(ret);
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@ -93,16 +107,27 @@ static pServerDynamicChannelContext* DynamicChannelContext_new(pServerContext* p
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ret->channelMode = pf_utils_get_channel_mode(ps->pdata->config, name);
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ret->openStatus = CHANNEL_OPENSTATE_OPENED;
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ret->packetReassembly = (ret->channelMode == PF_UTILS_CHANNEL_INTERCEPT);
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return ret;
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}
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static void DynamicChannelContext_free(pServerDynamicChannelContext* c)
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{
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if (c)
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{
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free(c->channel_name);
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free(c);
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}
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if (!c)
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return;
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if (c->backTracker.currentPacket)
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Stream_Free(c->backTracker.currentPacket, TRUE);
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if (c->frontTracker.currentPacket)
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Stream_Free(c->frontTracker.currentPacket, TRUE);
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if (c->channelDataDtor)
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c->channelDataDtor(&c->channelData);
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free(c->channelName);
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free(c);
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}
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static UINT32 ChannelId_Hash(const void* key)
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@ -321,7 +346,7 @@ static PfChannelResult DynvcTrackerPeekFn(ChannelStateTracker* tracker, BOOL fir
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return PF_CHANNEL_RESULT_ERROR;
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}
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if (!HashTable_Insert(dynChannelContext->channels, &dynChannel->channel_id,
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if (!HashTable_Insert(dynChannelContext->channels, &dynChannel->channelId,
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dynChannel))
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{
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WLog_ERR(TAG, "unable register dynamic channel context data");
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@ -340,14 +365,14 @@ static PfChannelResult DynvcTrackerPeekFn(ChannelStateTracker* tracker, BOOL fir
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Stream_Read_UINT32(s, creationStatus);
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WLog_DBG(TAG, "DynvcTracker(%" PRIu64 ",%s): %s CREATE_RESPONSE openStatus=%" PRIu32,
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dynChannelId, dynChannel->channel_name, direction, creationStatus);
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dynChannelId, dynChannel->channelName, direction, creationStatus);
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if (creationStatus != 0)
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{
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/* we remove it from the channels map, as it happens that server reused channel ids
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* when the channel can't be opened
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*/
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HashTable_Remove(dynChannelContext->channels, &dynChannel->channel_id);
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HashTable_Remove(dynChannelContext->channels, &dynChannel->channelId);
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}
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else
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{
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@ -361,7 +386,7 @@ static PfChannelResult DynvcTrackerPeekFn(ChannelStateTracker* tracker, BOOL fir
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if (!lastPacket)
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return PF_CHANNEL_RESULT_DROP;
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WLog_DBG(TAG, "DynvcTracker(%s): %s Close request on channel", dynChannel->channel_name,
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WLog_DBG(TAG, "DynvcTracker(%s): %s Close request on channel", dynChannel->channelName,
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direction);
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tracker->mode = CHANNEL_TRACKER_PASS;
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dynChannel->openStatus = CHANNEL_OPENSTATE_CLOSED;
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@ -398,7 +423,7 @@ static PfChannelResult DynvcTrackerPeekFn(ChannelStateTracker* tracker, BOOL fir
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if (dynChannel->openStatus != CHANNEL_OPENSTATE_OPENED)
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{
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WLog_ERR(TAG, "DynvcTracker(%s [%s]): channel is not opened", dynChannel->channel_name,
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WLog_ERR(TAG, "DynvcTracker(%s [%s]): channel is not opened", dynChannel->channelName,
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get_packet_type(cmd));
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return PF_CHANNEL_RESULT_ERROR;
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}
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@ -406,19 +431,48 @@ static PfChannelResult DynvcTrackerPeekFn(ChannelStateTracker* tracker, BOOL fir
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if ((cmd == DATA_FIRST_PDU) || (cmd == DATA_FIRST_COMPRESSED_PDU))
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{
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WLog_DBG(TAG, "DynvcTracker(%s [%s]): %s DATA_FIRST currentPacketLength=%" PRIu64 "",
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dynChannel->channel_name, get_packet_type(cmd), direction, Length);
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dynChannel->channelName, get_packet_type(cmd), direction, Length);
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trackerState->currentDataLength = Length;
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trackerState->CurrentDataReceived = 0;
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trackerState->CurrentDataFragments = 0;
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if (dynChannel->packetReassembly)
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{
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if (trackerState->currentPacket)
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Stream_SetPosition(trackerState->currentPacket, 0);
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}
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}
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if (cmd == DATA_PDU || cmd == DATA_FIRST_PDU)
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{
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size_t extraSize = Stream_GetRemainingLength(s);
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trackerState->CurrentDataFragments++;
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trackerState->CurrentDataReceived += Stream_GetRemainingLength(s);
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trackerState->CurrentDataReceived += extraSize;
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if (dynChannel->packetReassembly)
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{
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if (!trackerState->currentPacket)
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{
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trackerState->currentPacket = Stream_New(NULL, 1024);
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if (!trackerState->currentPacket)
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{
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WLog_ERR(TAG, "unable to create current packet");
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return PF_CHANNEL_RESULT_ERROR;
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}
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}
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if (!Stream_EnsureRemainingCapacity(trackerState->currentPacket, extraSize))
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{
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WLog_ERR(TAG, "unable to grow current packet");
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return PF_CHANNEL_RESULT_ERROR;
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}
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Stream_Write(trackerState->currentPacket, Stream_Pointer(s), extraSize);
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}
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WLog_DBG(TAG,
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"DynvcTracker(%s [%s]): %s frags=%" PRIu32 " received=%" PRIu32 "(%" PRIu32 ")",
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dynChannel->channel_name, get_packet_type(cmd), direction,
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dynChannel->channelName, get_packet_type(cmd), direction,
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trackerState->CurrentDataFragments, trackerState->CurrentDataReceived,
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trackerState->currentDataLength);
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}
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@ -432,7 +486,7 @@ static PfChannelResult DynvcTrackerPeekFn(ChannelStateTracker* tracker, BOOL fir
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WLog_ERR(TAG,
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"DynvcTracker (%s [%s]): reassembled packet (%" PRIu32
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") is bigger than announced length (%" PRIu32 ")",
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dynChannel->channel_name, get_packet_type(cmd),
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dynChannel->channelName, get_packet_type(cmd),
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trackerState->CurrentDataReceived, trackerState->currentDataLength);
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return PF_CHANNEL_RESULT_ERROR;
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}
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@ -444,27 +498,47 @@ static PfChannelResult DynvcTrackerPeekFn(ChannelStateTracker* tracker, BOOL fir
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}
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}
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if (trackerState->CurrentDataReceived == trackerState->currentDataLength)
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PfChannelResult result;
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switch (dynChannel->channelMode)
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{
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case PF_UTILS_CHANNEL_PASSTHROUGH:
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result = channelTracker_flushCurrent(tracker, firstPacket, lastPacket, !isBackData);
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break;
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case PF_UTILS_CHANNEL_BLOCK:
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tracker->mode = CHANNEL_TRACKER_DROP;
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result = PF_CHANNEL_RESULT_DROP;
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break;
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case PF_UTILS_CHANNEL_INTERCEPT:
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if (trackerState->dataCallback)
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{
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result = trackerState->dataCallback(pdata->ps, dynChannel, isBackData, tracker,
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firstPacket, lastPacket);
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}
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else
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{
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WLog_ERR(TAG, "no intercept callback for channel %s(fromBack=%d), dropping packet",
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dynChannel->channelName, isBackData);
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result = PF_CHANNEL_RESULT_DROP;
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}
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break;
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default:
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WLog_ERR(TAG, "unknown channel mode %d", dynChannel->channelMode);
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result = PF_CHANNEL_RESULT_ERROR;
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break;
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}
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if (!trackerState->currentDataLength ||
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(trackerState->CurrentDataReceived == trackerState->currentDataLength))
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{
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trackerState->currentDataLength = 0;
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trackerState->CurrentDataFragments = 0;
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trackerState->CurrentDataReceived = 0;
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if (dynChannel->packetReassembly && trackerState->currentPacket)
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Stream_SetPosition(trackerState->currentPacket, 0);
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}
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switch (dynChannel->channelMode)
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{
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case PF_UTILS_CHANNEL_PASSTHROUGH:
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return channelTracker_flushCurrent(tracker, firstPacket, lastPacket, !isBackData);
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case PF_UTILS_CHANNEL_BLOCK:
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tracker->mode = CHANNEL_TRACKER_DROP;
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return PF_CHANNEL_RESULT_DROP;
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case PF_UTILS_CHANNEL_INTERCEPT:
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WLog_DBG(TAG, "TODO: implement intercepted dynamic channel");
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return PF_CHANNEL_RESULT_DROP;
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default:
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WLog_ERR(TAG, "unknown channel mode");
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return PF_CHANNEL_RESULT_ERROR;
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}
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return result;
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}
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static void DynChannelContext_free(void* context)
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