Wireshark 解析PDCP-LTE

来源：互联网发布：网络策略编辑：程序博客网时间：2024/06/05 00:55

最近定位问题，把PDCP-LTE吐到wireshark上进行解析，但是UE-ID一直没法图出去，仔细研究了下wireshark PDCP-LTE相关的解析代码，发现除了DCT2000可以使用UE-ID，其他的解析程序是没有办法使用的，确实是比较遗憾的。

wireshark中PDCP-LTE结构体定义中有UE-ID，如下：

/* Info attached to each LTE PDCP/RoHC packet */
typedef struct pdcp_lte_info
{
    /* Channel info is needed for RRC parsing */
    guint8             direction;
    guint16            ueid;
    LogicalChannelType channelType;
    guint16            channelId;
    BCCHTransportType BCCHTransport;

    /* Details of PDCP header */
    gboolean           no_header_pdu;
    enum pdcp_plane    plane;
    guint8             seqnum_length;

    /* RoHC settings */
    gboolean           rohc_compression;
    unsigned short     rohc_ip_version;
    gboolean           cid_inclusion_info;
    gboolean           large_cid_present;
    enum rohc_mode     mode;
    gboolean           rnd;
    gboolean           udp_checksum_present;
    unsigned short     profile;

guint8 is_retx;
} pdcp_lte_info;

但是支持的解析类型中没有UE-ID

/* Conditional field. This field is mandatory in case of User Plane PDCP PDU.
The format is to have the tag, followed by the value (there is no length field,
it's implicit from the tag). The allowed values are defined above. */

#define PDCP_LTE_SEQNUM_LENGTH_TAG 0x02
/* 1 byte */

/* Optional fields. Attaching this info to frames will allow you
   to show you display/filter/plot/add-custom-columns on these fields, so should
   be added if available.
   The format is to have the tag, followed by the value (there is no length field,
   it's implicit from the tag) */

#define PDCP_LTE_DIRECTION_TAG 0x03
/* 1 byte */

#define PDCP_LTE_LOG_CHAN_TYPE_TAG 0x04
/* 1 byte */

#define PDCP_LTE_BCCH_TRANSPORT_TYPE_TAG 0x05
/* 1 byte */

#define PDCP_LTE_ROHC_IP_VERSION_TAG 0x06
/* 2 bytes, network order */

#define PDCP_LTE_ROHC_CID_INC_INFO_TAG 0x07
/* 1 byte */

#define PDCP_LTE_ROHC_LARGE_CID_PRES_TAG 0x08
/* 1 byte */

#define PDCP_LTE_ROHC_MODE_TAG 0x09
/* 1 byte */

#define PDCP_LTE_ROHC_RND_TAG 0x0A
/* 1 byte */

#define PDCP_LTE_ROHC_UDP_CHECKSUM_PRES_TAG 0x0B
/* 1 byte */

#define PDCP_LTE_ROHC_PROFILE_TAG 0x0C
/* 2 bytes, network order */

/* PDCP PDU. Following this tag comes the actual PDCP PDU (there is no length, the PDU
continues until the end of the frame) */
#define PDCP_LTE_PAYLOAD_TAG 0x01

如上是解析的Tag标记，在自己的程序中需要按照上述的TV格式来进行编码，wireshark是这样进行解析的：

/* Read optional fields */
    while (tag != PDCP_LTE_PAYLOAD_TAG) {
        /* Process next tag */
        tag = tvb_get_guint8(tvb, offset++);
        switch (tag) {
            case PDCP_LTE_SEQNUM_LENGTH_TAG:
                p_pdcp_lte_info->seqnum_length = tvb_get_guint8(tvb, offset);
                offset++;
                seqnumLengthTagPresent = TRUE;
                break;
            case PDCP_LTE_DIRECTION_TAG:
                p_pdcp_lte_info->direction = tvb_get_guint8(tvb, offset);
                offset++;
                break;
            case PDCP_LTE_LOG_CHAN_TYPE_TAG:
                p_pdcp_lte_info->channelType = (LogicalChannelType)tvb_get_guint8(tvb, offset);
                offset++;
                break;
            case PDCP_LTE_BCCH_TRANSPORT_TYPE_TAG:
                p_pdcp_lte_info->BCCHTransport = (BCCHTransportType)tvb_get_guint8(tvb, offset);
                offset++;
                break;
            case PDCP_LTE_ROHC_IP_VERSION_TAG:
                p_pdcp_lte_info->rohc_ip_version = tvb_get_ntohs(tvb, offset);
                offset += 2;
                break;
            case PDCP_LTE_ROHC_CID_INC_INFO_TAG:
                p_pdcp_lte_info->cid_inclusion_info = tvb_get_guint8(tvb, offset);
                offset++;
                break;
            case PDCP_LTE_ROHC_LARGE_CID_PRES_TAG:
                p_pdcp_lte_info->large_cid_present = tvb_get_guint8(tvb, offset);
                offset++;
                break;
            case PDCP_LTE_ROHC_MODE_TAG:
                p_pdcp_lte_info->mode = (enum rohc_mode)tvb_get_guint8(tvb, offset);
                offset++;
                break;
            case PDCP_LTE_ROHC_RND_TAG:
                p_pdcp_lte_info->rnd = tvb_get_guint8(tvb, offset);
                offset++;
                break;
            case PDCP_LTE_ROHC_UDP_CHECKSUM_PRES_TAG:
                p_pdcp_lte_info->udp_checksum_present = tvb_get_guint8(tvb, offset);
                offset++;
                break;
            case PDCP_LTE_ROHC_PROFILE_TAG:
                p_pdcp_lte_info->profile = tvb_get_ntohs(tvb, offset);
                offset += 2;
                break;

            case PDCP_LTE_PAYLOAD_TAG:
                /* Have reached data, so get out of loop */
                continue;

            default:
                /* It must be a recognised tag */
                return FALSE;
        }
    }

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