/* packet-vp8.c * Routines for VP8 dissection * Copyright 2014, Owen Williams williams.owen@gmail.com * * Wireshark - Network traffic analyzer * By Gerald Combs * Copyright 1998 Gerald Combs * * SPDX-License-Identifier: GPL-2.0-or-later */ /* * RFC 6386 - VP8 Data Format and Decoding Guide * RFC 7741 - RTP Payload Format for VP8 Video */ #include "config.h" #include #include #include void proto_reg_handoff_vp8(void); void proto_register_vp8(void); #define BIT_1_MASK 0x80 #define BIT_2_MASK 0x40 #define BIT_3_MASK 0x20 #define BIT_4_MASK 0x10 #define BIT_5_MASK 0x08 #define BIT_6_MASK 0x04 #define BIT_7_MASK 0x02 #define BIT_8_MASK 0x01 #define BIT_123_MASK 0xE0 #define BIT_234_MASK 0x70 #define BIT_5678_MASK 0x0F #define BIT_567_MASK 0x0E #define BIT_45678_MASK 0x1F #define BIT_12_MASK 0xC0 #define BIT_NO_MASK 0x0 #define BIT_2BYTE_NO_MASK 0x0 #define BIT_3BYTE_NO_MASK 0x0 #define BIT_EXT_PICTURE_MASK 0x7FFF #define BIT_PARTITION_SIZE_MASK 0xFFFFE0 static dissector_handle_t vp8_handle; /* Initialize the protocol and registered fields */ static int proto_vp8; static int hf_vp8_pld_x_bit; static int hf_vp8_pld_r_bit; static int hf_vp8_pld_n_bit; static int hf_vp8_pld_s_bit; static int hf_vp8_pld_part_id; static int hf_vp8_pld_i_bit; static int hf_vp8_pld_l_bit; static int hf_vp8_pld_t_bit; static int hf_vp8_pld_k_bit; static int hf_vp8_pld_rsv_a; static int hf_vp8_pld_picture_id; static int hf_vp8_pld_extended_picture_id; static int hf_vp8_pld_tl0picidx; static int hf_vp8_pld_tid; static int hf_vp8_pld_y_bit; static int hf_vp8_pld_keyidx; /* payload header fields */ static int hf_vp8_hdr_frametype; static int hf_vp8_hdr_version; static int hf_vp8_hdr_show_bit; static int hf_vp8_hdr_first_partition_size; /* keyframe fields */ static int hf_vp8_keyframe_start_code; static int hf_vp8_keyframe_width; static int hf_vp8_keyframe_horizontal_scale; static int hf_vp8_keyframe_height; static int hf_vp8_keyframe_vertical_scale; /* Initialize the subtree pointers */ static int ett_vp8; static int ett_vp8_payload_descriptor; static int ett_vp8_payload_header; static int ett_vp8_payload; static int ett_vp8_keyframe; static expert_field ei_vp8_startcode; static expert_field ei_vp8_undecoded; static expert_field ei_vp8_continuation; static expert_field ei_vp8_first_partition_split; static expert_field ei_vp8_first_partition_plus; static void dissect_vp8_payload_descriptor(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *vp8_tree, int *offset, bool *hasHeader); static void dissect_vp8_payload_header(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *vp8_tree, int *offset, int *frametype, int *partition1_size); static void dissect_vp8_payload(tvbuff_t *tvb, packet_info *pinfo, proto_tree *vp8_tree, int *offset, int *frametype, int *partition1_size); static int *ett[] = { &ett_vp8, &ett_vp8_payload_descriptor, &ett_vp8_payload_header, &ett_vp8_payload, &ett_vp8_keyframe }; static const value_string vp8_type_values[] = { { 0, "Keyframe" }, { 1, "Interframe" }, { 2, "Continuation" }, { 0, NULL } }; static const range_string vp8_hdr_version_vals[] = { { 0, 0, "Bicubic (Loop Filter=Normal)" }, { 1, 1, "Bilinear (Loop Filter=Simple)" }, { 2, 2, "Bilinear (Loop Filter=None)" }, { 3, 3, "No filters" }, { 4, 7, "Reserved for future use" }, { 0, 0, NULL } }; static const true_false_string vp8_x_bit_vals = { "Extended control bits present (I L T K)", "Extended control bits not present" }; static const true_false_string vp8_r_bit_vals = { "Reserved for future use (error: should be zero)", "Reserved for future use" }; static const true_false_string vp8_n_bit_vals = { "Non-reference frame", "Reference frame" }; static const true_false_string vp8_s_bit_vals = { "Start of VP8 partition", "Continuation of VP8 partition" }; static const true_false_string vp8_i_bit_vals = { "Picture ID byte present", "No Picture byte ID" }; static const true_false_string vp8_l_bit_vals = { "TL0PICIDX byte present", "TL0PICIDX byte not present" }; static const true_false_string vp8_t_bit_vals = { "TID (temporal layer index) present", "TID (temporal layer index) not present" }; static const true_false_string vp8_k_bit_vals = { "KEYIDX present", "KEYIDX not present" }; static const true_false_string vp8_hdr_frametype_vals = { "interframe", "keyframe" }; static int dissect_vp8(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_) { proto_item *item; int offset = 0, frametype = 0, partition1_size = -1; proto_tree *vp8_tree; bool hasHeader = false; col_set_str(pinfo->cinfo, COL_PROTOCOL, "VP8"); item = proto_tree_add_item(tree, proto_vp8, tvb, 0, -1, ENC_NA); vp8_tree = proto_item_add_subtree(item, ett_vp8); frametype = 2; /*continuation, will get overridden if there is a payload header*/ dissect_vp8_payload_descriptor(tvb, pinfo, vp8_tree, &offset, &hasHeader); if (hasHeader) { dissect_vp8_payload_header(tvb, pinfo, vp8_tree, &offset, &frametype, &partition1_size); } dissect_vp8_payload(tvb, pinfo, vp8_tree, &offset, &frametype, &partition1_size); col_append_fstr(pinfo->cinfo, COL_INFO, " - %s", val_to_str(frametype, vp8_type_values, "Unknown Type (%u)")); return tvb_captured_length(tvb); } static void dissect_vp8_payload_descriptor(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *vp8_tree, int *offset, bool *hasHeader) { proto_item *item_descriptor; uint8_t extended_bit, s_bit, partId; proto_tree *vp8_payload_descriptor_tree; /* The first octets after the RTP header are the VP8 payload descriptor, with the following structure. 0 1 2 3 4 5 6 7 +-+-+-+-+-+-+-+-+ |X|R|N|S|R| PID | (REQUIRED), second R bit is parsed as part of PID +-+-+-+-+-+-+-+-+ X: |I|L|T|K| RSV | (OPTIONAL) +-+-+-+-+-+-+-+-+ I: |M| PictureID | (OPTIONAL) +-+-+-+-+-+-+-+-+ L: | TL0PICIDX | (OPTIONAL) +-+-+-+-+-+-+-+-+ T/K: |TID|Y| KEYIDX | (OPTIONAL) +-+-+-+-+-+-+-+-+ */ vp8_payload_descriptor_tree = proto_tree_add_subtree(vp8_tree, tvb, *offset, -1, ett_vp8_payload_descriptor, &item_descriptor, "Payload descriptor"); proto_tree_add_item(vp8_payload_descriptor_tree, hf_vp8_pld_x_bit, tvb, *offset, 1, ENC_BIG_ENDIAN); proto_tree_add_item(vp8_payload_descriptor_tree, hf_vp8_pld_r_bit, tvb, *offset, 1, ENC_BIG_ENDIAN); proto_tree_add_item(vp8_payload_descriptor_tree, hf_vp8_pld_n_bit, tvb, *offset, 1, ENC_BIG_ENDIAN); proto_tree_add_item(vp8_payload_descriptor_tree, hf_vp8_pld_s_bit, tvb, *offset, 1, ENC_BIG_ENDIAN); proto_tree_add_item(vp8_payload_descriptor_tree, hf_vp8_pld_part_id, tvb, *offset, 1, ENC_BIG_ENDIAN); extended_bit = tvb_get_uint8(tvb, *offset) & BIT_1_MASK; s_bit = tvb_get_uint8(tvb, *offset) & BIT_4_MASK; partId = tvb_get_uint8(tvb, *offset) & BIT_5678_MASK; if ((s_bit > 0) && (partId == 0)) { *hasHeader=true; } if (extended_bit) { uint8_t i_bit, l_bit, t_bit, k_bit; (*offset)++; proto_tree_add_item(vp8_payload_descriptor_tree, hf_vp8_pld_i_bit, tvb, *offset, 1, ENC_BIG_ENDIAN); proto_tree_add_item(vp8_payload_descriptor_tree, hf_vp8_pld_l_bit, tvb, *offset, 1, ENC_BIG_ENDIAN); proto_tree_add_item(vp8_payload_descriptor_tree, hf_vp8_pld_t_bit, tvb, *offset, 1, ENC_BIG_ENDIAN); proto_tree_add_item(vp8_payload_descriptor_tree, hf_vp8_pld_k_bit, tvb, *offset, 1, ENC_BIG_ENDIAN); proto_tree_add_item(vp8_payload_descriptor_tree, hf_vp8_pld_rsv_a, tvb, *offset, 1, ENC_BIG_ENDIAN); i_bit = tvb_get_uint8(tvb, *offset) & BIT_1_MASK; l_bit = tvb_get_uint8(tvb, *offset) & BIT_2_MASK; t_bit = tvb_get_uint8(tvb, *offset) & BIT_3_MASK; k_bit = tvb_get_uint8(tvb, *offset) & BIT_4_MASK; if (i_bit) { (*offset)++; if(tvb_get_uint8(tvb, *offset) & BIT_1_MASK) { proto_tree_add_item(vp8_payload_descriptor_tree, hf_vp8_pld_extended_picture_id, tvb, *offset, 2, ENC_BIG_ENDIAN); (*offset)++; } else { proto_tree_add_item(vp8_payload_descriptor_tree, hf_vp8_pld_picture_id, tvb, *offset, 1, ENC_BIG_ENDIAN); } } if (l_bit) { (*offset)++; proto_tree_add_item(vp8_payload_descriptor_tree, hf_vp8_pld_tl0picidx, tvb, *offset, 1, ENC_BIG_ENDIAN); } if (t_bit || k_bit) { (*offset)++; proto_tree_add_item(vp8_payload_descriptor_tree, hf_vp8_pld_tid, tvb, *offset, 1, ENC_BIG_ENDIAN); proto_tree_add_item(vp8_payload_descriptor_tree, hf_vp8_pld_y_bit, tvb, *offset, 1, ENC_BIG_ENDIAN); proto_tree_add_item(vp8_payload_descriptor_tree, hf_vp8_pld_keyidx, tvb, *offset, 1, ENC_BIG_ENDIAN); } } (*offset)++; /* now we know the length of payload descriptor */ proto_item_set_len(item_descriptor, *offset); } static void dissect_vp8_payload_header(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *vp8_tree, int *offset, int *frametype, int *partition1_size) { proto_item *item_header; proto_tree *vp8_payload_header_tree; int size0, size1, size2; /* The first three octets of an encoded VP8 frame are referred to as an "uncompressed data chunk" in [RFC6386], and co-serve as payload header in this RTP format. The codec bitstream format specifies two different variants of the uncompressed data chunk: a 3 octet version for interframes and a 10 octet version for key frames. The first 3 octets are common to both variants. In the case of a key frame the remaining 7 octets are considered to be part of the remaining payload in this RTP format. Note that the header is present only in packets which have the S bit equal to one and the PartID equal to zero in the payload descriptor. Subsequent packets for the same frame do not carry the payload header. 0 1 2 3 4 5 6 7 +-+-+-+-+-+-+-+-+ |Size0|H| VER |P| +-+-+-+-+-+-+-+-+ | Size1 | +-+-+-+-+-+-+-+-+ | Size2 | +-+-+-+-+-+-+-+-+ | Bytes 4..N of | | VP8 payload | : : +-+-+-+-+-+-+-+-+ | OPTIONAL RTP | | padding | : : +-+-+-+-+-+-+-+-+ */ vp8_payload_header_tree = proto_tree_add_subtree(vp8_tree, tvb, *offset, 3, ett_vp8_payload_header, &item_header, "Payload header"); proto_tree_add_item(vp8_payload_header_tree, hf_vp8_hdr_frametype, tvb, *offset, 1, ENC_BIG_ENDIAN); proto_tree_add_item(vp8_payload_header_tree, hf_vp8_hdr_version, tvb, *offset, 1, ENC_BIG_ENDIAN); proto_tree_add_item(vp8_payload_header_tree, hf_vp8_hdr_show_bit, tvb, *offset, 1, ENC_BIG_ENDIAN); *frametype = tvb_get_uint8(tvb, *offset) & BIT_8_MASK; size0 = (tvb_get_uint8(tvb, *offset) & BIT_123_MASK) >> 5; size1 = tvb_get_uint8(tvb, *offset + 1); size2 = tvb_get_uint8(tvb, *offset + 2); (*partition1_size) = size0 + (size1*8) + (size2*2048); proto_tree_add_uint(vp8_payload_header_tree, hf_vp8_hdr_first_partition_size, tvb, *offset, 3, *partition1_size); (*offset) += 3; } static void dissect_vp8_payload(tvbuff_t *tvb, packet_info *pinfo, proto_tree *vp8_tree, int *offset, int *frametype, int *partition1_size) { proto_tree *vp8_payload_tree; proto_item *payload_item; int remainder; vp8_payload_tree = proto_tree_add_subtree(vp8_tree, tvb, *offset, -1, ett_vp8_payload, &payload_item, "Payload"); if (*frametype == 0) { uint16_t width, height; int start1, start2, start3, horizontal_scale, vertical_scale; proto_tree *vp8_keyframe_tree; vp8_keyframe_tree = proto_tree_add_subtree(vp8_payload_tree, tvb, *offset, -1, ett_vp8_keyframe, NULL, "Keyframe header"); proto_tree_add_item(vp8_keyframe_tree, hf_vp8_keyframe_start_code, tvb, *offset, 3, ENC_BIG_ENDIAN); start1 = tvb_get_uint8(tvb, *offset); start2 = tvb_get_uint8(tvb, *offset + 1); start3 = tvb_get_uint8(tvb, *offset + 2); /* check start code is correct */ if ((start1 != 0x9d) || (start2 != 0x01) || (start3 != 0x2a)) { expert_add_info(pinfo, vp8_keyframe_tree, &ei_vp8_startcode); } (*offset)++; (*offset)++; (*offset)++; width = tvb_get_letohs(tvb, *offset) & 0x3FFF; horizontal_scale = tvb_get_letohs(tvb, *offset)>>14; proto_tree_add_uint(vp8_keyframe_tree, hf_vp8_keyframe_horizontal_scale, tvb, *offset, 2, horizontal_scale); proto_tree_add_uint(vp8_keyframe_tree, hf_vp8_keyframe_width, tvb, *offset, 2, width); (*offset)++; (*offset)++; height = tvb_get_letohs(tvb, *offset) & 0x3FFF; vertical_scale = tvb_get_letohs(tvb, *offset)>>14; proto_tree_add_uint(vp8_keyframe_tree, hf_vp8_keyframe_vertical_scale, tvb, *offset, 2, vertical_scale); proto_tree_add_uint(vp8_keyframe_tree, hf_vp8_keyframe_height, tvb, *offset, 2, height); (*offset)++; (*offset)++; } remainder = tvb_reported_length_remaining(tvb, (*offset)); if ((*partition1_size) == -1) { /*no header, continuation?*/ proto_tree_add_expert_format(vp8_payload_tree, pinfo, &ei_vp8_continuation, tvb, *offset, -1, "Continuation of partition fragment (%d bytes)", remainder); } else { if (remainder < *partition1_size) { /* partition size has already been added to vp8 header tree, but it would be useful to provide additional explanation */ proto_tree_add_expert_format(vp8_payload_tree, pinfo, &ei_vp8_first_partition_split, tvb, *offset, -1, "First partition is split with %d bytes in this packet and %d bytes in subsequent frames", remainder, ((*partition1_size)-remainder)); } else { (*offset)= (*offset) + (*partition1_size); proto_tree_add_expert_format(vp8_payload_tree, pinfo, &ei_vp8_first_partition_plus, tvb, *offset, -1, "This frame contains all of first partition (%d bytes) and also %d bytes from other partitions", *partition1_size, remainder); } } expert_add_info(pinfo, payload_item, &ei_vp8_undecoded); } void proto_register_vp8(void) { module_t *vp8_module; expert_module_t* expert_vp8; static hf_register_info hf[] = { { &hf_vp8_pld_x_bit, { "X bit", "vp8.pld.x", FT_BOOLEAN, 8, TFS(&vp8_x_bit_vals), BIT_1_MASK, NULL, HFILL } }, { &hf_vp8_pld_r_bit, { "R bit", "vp8.pld.r", FT_BOOLEAN, 8, TFS(&vp8_r_bit_vals), BIT_2_MASK, NULL, HFILL } }, { &hf_vp8_pld_n_bit, { "N bit", "vp8.pld.n", FT_BOOLEAN, 8, TFS(&vp8_n_bit_vals), BIT_3_MASK, NULL, HFILL } }, { &hf_vp8_pld_s_bit, { "S bit", "vp8.pld.s", FT_BOOLEAN, 8, TFS(&vp8_s_bit_vals), BIT_4_MASK, NULL, HFILL } }, { &hf_vp8_pld_part_id, { "2nd R bit and Part Id", "vp8.pld.partid", FT_UINT8, BASE_DEC, NULL, BIT_5678_MASK, NULL, HFILL } }, { &hf_vp8_pld_i_bit, { "I bit", "vp8.pld.i", FT_BOOLEAN, 8, TFS(&vp8_i_bit_vals), BIT_1_MASK, NULL, HFILL } }, { &hf_vp8_pld_l_bit, { "L bit", "vp8.pld.l", FT_BOOLEAN, 8, TFS(&vp8_l_bit_vals), BIT_2_MASK, NULL, HFILL } }, { &hf_vp8_pld_t_bit, { "T bit", "vp8.pld.t", FT_BOOLEAN, 8, TFS(&vp8_t_bit_vals), BIT_3_MASK, NULL, HFILL } }, { &hf_vp8_pld_k_bit, { "K bit", "vp8.pld.k", FT_BOOLEAN, 8, TFS(&vp8_k_bit_vals), BIT_4_MASK, NULL, HFILL } }, { &hf_vp8_pld_rsv_a, { "Reserved A", "vp8.pld.rsva", FT_UINT8, BASE_DEC, NULL, BIT_5678_MASK, NULL, HFILL } }, { &hf_vp8_pld_picture_id, { "Picture ID", "vp8.pld.pictureid", FT_UINT8, BASE_DEC, NULL, BIT_NO_MASK, NULL, HFILL } }, { &hf_vp8_pld_extended_picture_id, { "Extended Picture ID", "vp8.pld.pictureid", FT_UINT16, BASE_DEC, NULL, BIT_EXT_PICTURE_MASK, NULL, HFILL } }, { &hf_vp8_pld_tl0picidx, { "Temporal layer zero Picture Index (TL0PICIDX)", "vp8.pld.tl0picidx", FT_UINT8, BASE_DEC, NULL, BIT_NO_MASK, NULL, HFILL } }, { &hf_vp8_pld_tid, { "Temporal layer Index (TID)", "vp8.pld.tid", FT_UINT8, BASE_DEC, NULL, BIT_12_MASK, NULL, HFILL } }, { &hf_vp8_pld_y_bit, { "1 layer sync bit (Y)", "vp8.pld.y", FT_BOOLEAN, 8, NULL, BIT_3_MASK, NULL, HFILL } }, { &hf_vp8_pld_keyidx, { "Temporal Key Frame Index (KEYIDX)", "vp8.pld.keyidx", FT_UINT8, BASE_DEC, NULL, BIT_45678_MASK, NULL, HFILL } }, { &hf_vp8_hdr_frametype, { "frametype", "vp8.hdr.frametype", FT_BOOLEAN, 8, TFS(&vp8_hdr_frametype_vals), BIT_8_MASK, NULL, HFILL } }, { &hf_vp8_hdr_version, { "version", "vp8.hdr.version", FT_UINT8, BASE_DEC | BASE_RANGE_STRING, RVALS(vp8_hdr_version_vals), BIT_567_MASK, NULL, HFILL } }, { &hf_vp8_hdr_show_bit, { "Show bit", "vp8.hdr.show", FT_BOOLEAN, 8, NULL, BIT_4_MASK, "Set when current frame is for display", HFILL } }, { &hf_vp8_hdr_first_partition_size, { "First partition size", "vp8.hdr.partition_size", FT_UINT24, BASE_DEC, NULL, BIT_PARTITION_SIZE_MASK, NULL, HFILL } }, { &hf_vp8_keyframe_start_code, { "VP8 Start code", "vp8.keyframe.start_code", FT_UINT24, BASE_HEX, NULL, BIT_3BYTE_NO_MASK, NULL, HFILL } }, { &hf_vp8_keyframe_width, { "Width", "vp8.keyframe.width", FT_UINT16, BASE_DEC, NULL, BIT_2BYTE_NO_MASK, NULL, HFILL } }, { &hf_vp8_keyframe_height, { "Height", "vp8.keyframe.height", FT_UINT16, BASE_DEC, NULL, BIT_2BYTE_NO_MASK, NULL, HFILL } }, { &hf_vp8_keyframe_horizontal_scale, { "Horizontal Scale", "vp8.keyframe.horizontal_scale", FT_UINT8, BASE_DEC, NULL, BIT_12_MASK, NULL, HFILL } }, { &hf_vp8_keyframe_vertical_scale, { "Vertical Scale", "vp8.keyframe.vertical_scale", FT_UINT8, BASE_DEC, NULL, BIT_12_MASK, NULL, HFILL } } }; static ei_register_info ei[] = { { &ei_vp8_startcode, { "vp8.keyframe.startcode", PI_PROTOCOL, PI_ERROR, "Startcode is incorrect", EXPFILL }}, { &ei_vp8_undecoded, { "vp8.undecoded", PI_UNDECODED, PI_NOTE, "Payload not fully decoded", EXPFILL }}, { &ei_vp8_continuation, { "vp8.continuation", PI_REASSEMBLE, PI_CHAT, "Continuation of partition fragment", EXPFILL }}, { &ei_vp8_first_partition_split, { "vp8.first_partition_split", PI_REASSEMBLE, PI_CHAT, "First partition is split", EXPFILL }}, { &ei_vp8_first_partition_plus, { "vp8.first_partition_plus", PI_REASSEMBLE, PI_CHAT, "This frame contains all of first partition and also bytes from other partitions", EXPFILL }}, }; proto_vp8 = proto_register_protocol ( "VP8", /* name */ "VP8", /* short name */ "vp8" /* abbrev */ ); proto_register_field_array(proto_vp8, hf, array_length(hf)); proto_register_subtree_array(ett, array_length(ett)); vp8_module = prefs_register_protocol(proto_vp8, NULL); expert_vp8 = expert_register_protocol(proto_vp8); expert_register_field_array(expert_vp8, ei, array_length(ei)); prefs_register_obsolete_preference(vp8_module, "dynamic.payload.type"); vp8_handle = register_dissector("vp8", dissect_vp8, proto_vp8); } void proto_reg_handoff_vp8(void) { dissector_add_string("rtp_dyn_payload_type" , "VP8", vp8_handle); dissector_add_uint_range_with_preference("rtp.pt", "", vp8_handle); } /* * Editor modelines - https://www.wireshark.org/tools/modelines.html * * Local variables: * c-basic-offset: 4 * tab-width: 8 * indent-tabs-mode: nil * End: * * vi: set shiftwidth=4 tabstop=8 expandtab: * :indentSize=4:tabSize=8:noTabs=true: */