epan/dissectors/packet-smpte-2110-20.c

   1 /* packet-smpte-2110-20.c
   2  * SMPTE ST2110-20
   3  *
   4  * Copyright 2023, Sergey V. Lobanov <sergey@lobanov.in>
   5  *
   6  * References:
   7  *     SMPTE ST 2110-20:2022, Uncompressed Active Video
   8  *     RFC4175, RTP Payload Format for Uncompressed Video
   9  *
  10  * Wireshark - Network traffic analyzer
  11  * By Gerald Combs <gerald@wireshark.org>
  12  * Copyright 1998 Gerald Combs
  13  *
  14  * SPDX-License-Identifier: GPL-2.0-or-later
  15  */
  16
  17 #include "config.h"
  18
  19 #include <epan/packet.h>
  20 #include <epan/prefs.h>
  21 #include <epan/proto.h>
  22 #include <epan/proto_data.h>
  23
  24 #include "packet-rtp.h"
  25
  26 void proto_reg_handoff_st2110_20(void);
  27 void proto_register_st2110_20(void);
  28
  29 static dissector_handle_t st2110_20_handle;
  30
  31 /* Initialize the protocol and registered fields */
  32 static int proto_st2110_20;
  33 static int proto_rtp;
  34
  35 static int hf_st2110_ext_seqno;
  36 static int hf_st2110_seqno;
  37 static int hf_st2110_rtp_time;
  38 static int hf_st2110_srd_index;
  39 static int hf_st2110_srd_length;
  40 static int hf_st2110_field_ident;
  41 static int hf_st2110_row_num;
  42 static int hf_st2110_continuation;
  43 static int hf_st2110_srd_offset;
  44 static int hf_st2110_srd_data;
  45 static int hf_st2110_srd_rows;
  46
  47 /* Initialize the subtree pointers */
  48 static int ett_st2110_20;
  49 static int ett_st2110_20_srd_row;
  50
  51
  52 static int
  53 dissect_st2110_20(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree _U_, void* data _U_)
  54 {
  55     proto_item *item;
  56     proto_tree *st2110_20_tree;
  57
  58     int offset = 0;
  59
  60     struct _rtp_packet_info *rtp_pkt_info = (struct _rtp_packet_info *)p_get_proto_data(wmem_file_scope(), pinfo, proto_rtp, RTP_CONVERSATION_PROTO_DATA);
  61
  62     col_set_str(pinfo->cinfo, COL_PROTOCOL, "ST2110-20");
  63
  64     item = proto_tree_add_item(tree, proto_st2110_20, tvb, 0, -1, ENC_NA);
  65     st2110_20_tree = proto_item_add_subtree(item, ett_st2110_20);
  66
  67     /* Extract original RTP sequence number from low bits */
  68     uint32_t rtp_seqno = (rtp_pkt_info != NULL) ? (rtp_pkt_info->extended_seqno & 0xFFFF) : 0;
  69     /* ST2110-20 extended sequence number field */
  70     uint32_t ext_seqno = tvb_get_uint16(tvb, offset, ENC_BIG_ENDIAN);
  71     /* Sequence number (RTP seqno is low bits, ST2110-20 ext seqno is high bits) */
  72     uint32_t seqno = (ext_seqno << 16) + rtp_seqno;
  73
  74     /* Extract original RTP timestamp */
  75     uint32_t rtp_time = (rtp_pkt_info != NULL) ? (uint32_t)(rtp_pkt_info->extended_timestamp & 0xFFFFFFFF) : 0;
  76
  77     proto_tree_add_item(st2110_20_tree, hf_st2110_ext_seqno, tvb, offset, 2, ENC_BIG_ENDIAN);
  78     PROTO_ITEM_SET_GENERATED(
  79             proto_tree_add_uint(st2110_20_tree, hf_st2110_seqno, tvb, offset, 2, seqno)
  80     );
  81     PROTO_ITEM_SET_GENERATED(
  82             proto_tree_add_uint(st2110_20_tree, hf_st2110_rtp_time, NULL, 0, 0, rtp_time)
  83     );
  84     offset += 2; /* st2110-20 ext seqno */
  85
  86     /* According to ST2110-20:2022 6.2.1, max three SRD headers might be in a packet */
  87     uint16_t srd_lengths[3] = {0, 0, 0}; /* store for second pass */
  88     proto_tree* srd_header_trees[3] = {NULL, NULL, NULL}; /* store for second pass */
  89     uint8_t srd_rows = 0; /* rows count */
  90     uint16_t first_row; /* first row number */
  91     for (uint8_t srd_idx = 0; srd_idx < 3 ; srd_idx++) {
  92         proto_tree *srd_header_tree = proto_tree_add_subtree_format(st2110_20_tree, tvb, offset, 6,
  93                                     ett_st2110_20_srd_row, &item, "Sample Row Data %u", srd_idx);
  94         srd_header_trees[srd_idx] = srd_header_tree;
  95         PROTO_ITEM_SET_GENERATED(
  96             proto_tree_add_uint(srd_header_tree, hf_st2110_srd_index, NULL, 0, 0, srd_idx)
  97         );
  98
  99         srd_lengths[srd_idx] = tvb_get_uint16(tvb, offset, ENC_BIG_ENDIAN);
 100         proto_tree_add_item(srd_header_tree, hf_st2110_srd_length, tvb, offset, 2, ENC_BIG_ENDIAN);
 101         offset += 2;
 102
 103         first_row = (srd_idx == 0) ? (tvb_get_uint16(tvb, offset, ENC_BIG_ENDIAN) & 0x7FFF) : first_row;
 104         proto_tree_add_item(srd_header_tree, hf_st2110_field_ident, tvb, offset, 2, ENC_BIG_ENDIAN);
 105         proto_tree_add_item(srd_header_tree, hf_st2110_row_num, tvb, offset, 2, ENC_BIG_ENDIAN);
 106         offset += 2;
 107
 108         uint16_t cont_bit = tvb_get_uint16(tvb, offset, ENC_BIG_ENDIAN) >> 15;
 109         proto_tree_add_item(srd_header_tree, hf_st2110_continuation, tvb, offset, 2, ENC_BIG_ENDIAN);
 110         proto_tree_add_item(srd_header_tree, hf_st2110_srd_offset, tvb, offset, 2, ENC_BIG_ENDIAN);
 111         offset += 2;
 112
 113         srd_rows++;
 114
 115         if (cont_bit != 1) /* if continuation is not set, then no more headers*/
 116             break;
 117     }
 118
 119     PROTO_ITEM_SET_GENERATED(
 120         proto_tree_add_uint(st2110_20_tree, hf_st2110_srd_rows, NULL, 0, 0, srd_rows)
 121     );
 122
 123     /* Second pass, get SRD data and add it to the same trees created for SRD headers */
 124     for (uint8_t srd_idx = 0; srd_idx < srd_rows ; srd_idx++) {
 125         uint16_t srd_length = srd_lengths[srd_idx];
 126
 127         proto_tree_add_item(srd_header_trees[srd_idx], hf_st2110_srd_data, tvb, offset, srd_length, ENC_NA);
 128         offset += srd_length;
 129     }
 130
 131     col_add_fstr(pinfo->cinfo, COL_INFO, "Seq=%u, Time=%u, FirstRow=%u, Rows=%u", seqno, rtp_time, first_row, srd_rows);
 132
 133     return offset;
 134 }
 135
 136 void
 137 proto_register_st2110_20(void)
 138 {
 139     module_t *st2110_20_module;
 140
 141     static hf_register_info hf[] = {
 142         { &hf_st2110_ext_seqno,
 143           { "Extended Sequence Number", "st2110_20.ext_seq",
 144             FT_UINT16, BASE_DEC, NULL, 0x0,
 145             NULL, HFILL }
 146         },
 147         { &hf_st2110_seqno,
 148           { "Sequence Number", "st2110_20.seq",
 149             FT_UINT16, BASE_DEC, NULL, 0x0,
 150             NULL, HFILL }
 151         },
 152         { &hf_st2110_rtp_time,
 153           { "RTP Timestamp", "st2110_20.rtp_timestamp",
 154             FT_UINT32, BASE_DEC, NULL, 0x0,
 155             NULL, HFILL }
 156         },
 157         { &hf_st2110_srd_index,
 158           { "SRD Header Index", "st2110_20.srd_index",
 159             FT_UINT8, BASE_DEC, NULL, 0x0,
 160             NULL, HFILL }
 161         },
 162         { &hf_st2110_srd_length,
 163           { "SRD Length", "st2110_20.srd_length",
 164             FT_UINT16, BASE_DEC, NULL, 0x0,
 165             NULL, HFILL }
 166         },
 167         { &hf_st2110_field_ident,
 168           { "Field Identification Bit", "st2110_20.srd_field_ident",
 169             FT_UINT16, BASE_DEC, NULL, 0x8000,
 170             NULL, HFILL }
 171         },
 172         { &hf_st2110_row_num,
 173           { "SRD Row Number", "st2110_20.srd_row_num",
 174             FT_UINT16, BASE_DEC, NULL, 0x7FFF,
 175             NULL, HFILL }
 176         },
 177         { &hf_st2110_continuation,
 178           { "SRD Continuation Bit", "st2110_20.srd_cont_bit",
 179             FT_UINT16, BASE_DEC, NULL, 0x8000,
 180             NULL, HFILL }
 181         },
 182         { &hf_st2110_srd_offset,
 183           { "SRD Offset", "st2110_20.srd_offset",
 184             FT_UINT16, BASE_DEC, NULL, 0x7FFF,
 185             NULL, HFILL }
 186         },
 187         { &hf_st2110_srd_data,
 188           { "SRD Data", "st2110_20.srd_data",
 189             FT_NONE, BASE_NONE, NULL, 0x0,
 190             NULL, HFILL }
 191         },
 192         { &hf_st2110_srd_rows,
 193           { "SRD Rows", "st2110_20.srd_rows",
 194             FT_UINT8, BASE_DEC, NULL, 0x0,
 195             NULL, HFILL }
 196         }
 197     };
 198
 199     static int *ett[] =
 200     {
 201         &ett_st2110_20,
 202         &ett_st2110_20_srd_row
 203     };
 204
 205     proto_st2110_20  = proto_register_protocol("SMPTE ST2110-20 (Uncompressed Active Video)", "ST2110-20", "st2110_20");
 206
 207     proto_register_field_array(proto_st2110_20, hf, array_length(hf));
 208     proto_register_subtree_array(ett, array_length(ett));
 209
 210     st2110_20_module = prefs_register_protocol(proto_st2110_20, NULL);
 211
 212     prefs_register_obsolete_preference(st2110_20_module, "dynamic.payload.type");
 213     st2110_20_handle = register_dissector("st2110_20", dissect_st2110_20, proto_st2110_20);
 214 }
 215
 216 void
 217 proto_reg_handoff_st2110_20(void)
 218 {
 219     dissector_add_string("rtp_dyn_payload_type" , "ST2110-20", st2110_20_handle);
 220     dissector_add_uint_range_with_preference("rtp.pt", "", st2110_20_handle);
 221     proto_rtp = proto_get_id_by_filter_name("rtp");
 222 }
 223
 224 /*
 225  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 226  *
 227  * Local variables:
 228  * c-basic-offset: 4
 229  * tab-width: 8
 230  * indent-tabs-mode: nil
 231  * End:
 232  *
 233  * vi: set shiftwidth=4 tabstop=8 expandtab:
 234  * :indentSize=4:tabSize=8:noTabs=true:
 235  */