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|
-- @brief srt-dev Protocol dissector plugin
-- create a new dissector
local NAME = "SRT-dev"
local srt_dev = Proto(NAME, "SRT-dev Protocol")
-- create a preference of a Protocol
srt_dev.prefs["srt_udp_port"] = Pref.uint("SRT UDP Port", 1935, "SRT UDP Port")
-- create fields of srt_dev
-- Base.HEX, Base.DEC, Base.OCT, Base.UNIT_STRING, Base.NONE
local fields = srt_dev.fields
-- General field
local pack_type_select = {
[0] = "Data Packet",
[1] = "Control Packet"
}
fields.pack_type_tree = ProtoField.uint32(NAME .. ".pack_type_tree", "Packet Type", base.HEX)
fields.pack_type = ProtoField.uint16("srt_dev.pack_type", "Packet Type", base.HEX, pack_type_select, 0x8000)
fields.reserve = ProtoField.uint16("srt_dev.reserve", "Reserve", base.DEC)
fields.additional_info = ProtoField.uint32("srt_dev.additional_info", "Additional Information", base.DEC)
fields.time_stamp = ProtoField.uint32("srt_dev.time_stamp", "Time Stamp", base.DEC)
fields.dst_sock = ProtoField.uint32("srt_dev.dst_sock", "Destination Socket ID", base.DEC)
fields.none = ProtoField.none("srt_dev.none", "none", base.NONE)
-- Data packet fields
fields.data_flag_info_tree = ProtoField.uint8("srt_dev.data_flag_info_tree", "Data Flag Info", base.HEX)
local FF_state_select = {
[0] = "[Middle packet]",
[1] = "[Last packet]",
[2] = "[First packet]",
[3] = "[Single packet]"
}
fields.FF_state = ProtoField.uint8("srt_dev.FF_state", "FF state", base.HEX, FF_state_select, 0xC0)
local O_state_select = {
[0] = "[ORD_RELAX]",
[1] = "[ORD_REQUIRED]"
}
fields.O_state = ProtoField.uint8("srt_dev.O_state", "O state", base.HEX, O_state_select, 0x20)
local KK_state_select = {
[0] = "[Not encrypted]",
[1] = "[Data encrypted with even key]",
[2] = "[Data encrypted with odd key]"
}
fields.KK_state = ProtoField.uint8("srt_dev.KK_state", "KK state", base.HEX, KK_state_select, 0x18)
local R_state_select = {
[0] = "[ORIGINAL]",
[1] = "[RETRANSMITTED]"
}
fields.R_state = ProtoField.uint8("srt_dev.R_state", "R state", base.HEX, R_state_select, 0x04)
fields.seq_num = ProtoField.uint32("srt_dev.seq_num", "Sequence Number", base.DEC)
fields.msg_num = ProtoField.uint32("srt_dev.msg_num", "Message Number", base.DEC)--, nil, 0x3FFFFFF)
-- control packet fields
local msg_type_select = {
[0] = "[HANDSHAKE]",
[1] = "[KEEPALIVE]",
[2] = "[ACK]",
[3] = "[NAK(Loss Report)]",
[4] = "[Congestion Warning]",
[5] = "[Shutdown]",
[6] = "[ACKACK]",
[7] = "[Drop Request]",
[8] = "[Peer Error]",
[0x7FFF] = "[Message Extension Type]"
}
fields.msg_type = ProtoField.uint16("srt_dev.msg_type", "Message Type", base.HEX, msg_type_select, 0x7FFF)
fields.msg_ext_type = ProtoField.uint16("srt_dev.msg_ext_type", "Message Extented Type", base.DEC)
local flag_state_select = {
[0] = "Unset",
[1] = "Set"
}
-- Handshake packet fields
fields.UDT_version = ProtoField.uint32("srt_dev.UDT_version", "UDT Version", base.DEC)
fields.sock_type = ProtoField.uint32("srt_dev.sock_type", "Socket Type", base.DEC)
fields.ency_fld = ProtoField.uint16("srt_dev.ency_fld", "Encryption Field", base.DEC)
fields.ext_fld = ProtoField.uint16("srt_dev.ext_fld", "Extension Fields", base.HEX)
fields.ext_fld_tree = ProtoField.uint16("srt_dev.ext_fld_tree", "Extension Fields Tree", base.HEX)
fields.hsreq = ProtoField.uint16("srt_dev.hsreq", "HS_EXT_HSREQ", base.HEX, flag_state_select, 0x1)
fields.kmreq = ProtoField.uint16("srt_dev.kmreq", "HS_EXT_KMREQ", base.HEX, flag_state_select, 0x2)
fields.config = ProtoField.uint16("srt_dev.config", "HS_EXT_CONFIG", base.HEX, flag_state_select, 0x4)
fields.isn = ProtoField.uint32("srt_dev.isn", "Initial packet sequence number", base.DEC)
fields.mss = ProtoField.uint32("srt_dev.mss", "Max Packet Size", base.DEC)
fields.fc = ProtoField.uint32("srt_dev.fc", "Maximum Flow Window Size", base.DEC)
fields.conn_type = ProtoField.int32("srt_dev.conn_type", "Connection Type", base.DEC)
fields.sock_id = ProtoField.uint32("srt_dev.sock_id", "Socket ID", base.DEC)
fields.syn_cookie = ProtoField.uint32("srt_dev.syn_cookie", "SYN cookie", base.DEC)
fields.peer_ipaddr = ProtoField.none("srt_dev.peer_ipaddr", "Peer IP address", base.NONE)
fields.peer_ipaddr_4 = ProtoField.ipv4("srt_dev.peer_ipaddr", "Peer IP address")
fields.peer_ipaddr_6 = ProtoField.ipv6("srt_dev.peer_ipaddr", "Peer IP address")
local ext_type_select = {
[-1] = "SRT_CMD_NONE",
[0] = "SRT_CMD_REJECT",
[1] = "SRT_CMD_HSREQ",
[2] = "SRT_CMD_HSRSP",
[3] = "SRT_CMD_KMREQ",
[4] = "SRT_CMD_KMRSP",
[5] = "SRT_CMD_SID",
[6] = "SRT_CMD_CONGESTION",
[7] = "SRT_CMD_FILTER",
[8] = "SRT_CMD_GROUP"
}
fields.ext_type_msg_tree = ProtoField.none("srt_dev.ext_type", "Extension Type Message", base.NONE)
fields.ext_type = ProtoField.uint16("srt_dev.ext_type", "Extension Type", base.HEX, ext_type_select, 0xF)
fields.ext_size = ProtoField.uint16("srt_dev.ext_size", "Extension Size", base.DEC)
-- Handshake packet, ext type == SRT_CMD_HSREQ or SRT_CMD_HSRSP field
fields.srt_version = ProtoField.uint32("srt_dev.srt_version", "SRT Version", base.HEX)
fields.srt_flags = ProtoField.uint32("srt_dev.srt_flags", "SRT Flags", base.HEX)
fields.tsbpb_resv = ProtoField.uint16("srt_dev.tsbpb_resv", "TsbPb Receive", base.DEC)
fields.tsbpb_delay = ProtoField.uint16("srt_dev.tsbpb_delay", "TsbPb Delay", base.DEC)
fields.tsbpd_delay = ProtoField.uint16("srt_dev.tsbpd_delay", "TsbPd Delay", base.DEC)
fields.rcv_tsbpd_delay = ProtoField.uint16("srt_dev.rcv_tsbpd_delay", "Receiver TsbPd Delay", base.DEC)
fields.snd_tsbpd_delay = ProtoField.uint16("srt_dev.snd_tsbpd_delay", "Sender TsbPd Delay", base.DEC)
-- V and PT status flag
local V_state_select = {
[1] = "Initial version"
}
fields.V_state = ProtoField.uint8("srt_dev.V_state", "V", base.HEX, V_state_select, 0x70)
local PT_state_select = {
[0] = "Reserved",
[1] = "MSmsg",
[2] = "KMmsg",
[7] = "Reserved to discriminate MPEG-TS packet(0x47=sync byte)"
}
fields.PT_state = ProtoField.uint8("srt_dev.PT_state", "PT", base.HEX, state_table, 0xF)
fields.sign = ProtoField.uint16("srt_dev.sign", "Signature", base.HEX)
local resv_select = {
[0] = "Reserved for flag extension or other usage"
}
fields.resv = ProtoField.uint8("srt_dev.resv", "Resv", base.DEC, state_table, 0xFC)
fields.ext_KK_state = ProtoField.uint8("srt_dev.ext_KK_state", "KK_state", base.HEX, KK_state_select, 0x3)
fields.KEKI = ProtoField.uint32("srt_dev.KEKI", "KEKI", base.DEC)
fields.cipher = ProtoField.uint8("srt_dev.cipher", "Cipher", base.DEC)
fields.auth = ProtoField.uint8("srt_dev.auth", "auth", base.DEC)
fields.SE = ProtoField.uint8("srt_dev.SE", "SE", base.DEC)
fields.resv1 = ProtoField.uint8("srt_dev.resv1", "resv1", base.DEC)
fields.resv2 = ProtoField.uint16("srt_dev.resv2", "resv2", base.DEC)
fields.slen = ProtoField.uint8("srt_dev.slen", "Salt length(bytes)/4", base.DEC)
fields.klen = ProtoField.uint8("srt_dev.klen", "SEK length(bytes)/4", base.DEC)
fields.salt = ProtoField.uint32("srt_dev.salt", "Salt key", base.DEC)
fields.wrap = ProtoField.none("srt_dev.wrap", "Wrap key(s)", base.NONE)
-- Wrap Field
fields.ICV = ProtoField.uint64("srt_dev.ICV", "Integerity Check Vector", base.HEX)
fields.odd_key = ProtoField.stringz("srt_dev.odd_key", "Odd key", base.ASCII)
fields.even_key = ProtoField.stringz("srt_dev.even_key", "Even key", base.ASCII)
-- ext_type == SRT_CMD_SID field
fields.sid = ProtoField.string("srt_dev.sid", "Stream ID", base.ASCII)
-- ext_type == SRT_CMD_CONGESTION field
fields.congestion = ProtoField.string("srt_dev.congestion", "Congestion Controller", base.ASCII)
-- ext_type == SRT_CMD_FILTER field
fields.filter = ProtoField.string("srt_dev.filter", "Filter", base.ASCII)
-- ext_type == SRT_CMD_GROUP field
fields.group = ProtoField.string("srt_dev.group", "Group Data", base.ASCII)
-- SRT flags
fields.srt_opt_tsbpdsnd = ProtoField.uint32("srt_dev.srt_opt_tsbpdsnd", "SRT_OPT_TSBPDSND", base.HEX, flag_state_select, 0x1)
fields.srt_opt_tsbpdrcv = ProtoField.uint32("srt_dev.srt_opt_tsbpdrcv", "SRT_OPT_TSBPDRCV", base.HEX, flag_state_select, 0x2)
fields.srt_opt_haicrypt = ProtoField.uint32("srt_dev.srt_opt_haicrypt", "SRT_OPT_HAICRYPT", base.HEX, flag_state_select, 0x4)
fields.srt_opt_tlpktdrop = ProtoField.uint32("srt_dev.srt_opt_tlpktdrop", "SRT_OPT_TLPKTDROP", base.HEX, flag_state_select, 0x8)
fields.srt_opt_nakreport = ProtoField.uint32("srt_dev.srt_opt_nakreport", "SRT_OPT_NAKREPORT", base.HEX, flag_state_select, 0x10)
fields.srt_opt_rexmitflg = ProtoField.uint32("srt_dev.srt_opt_rexmitflg", "SRT_OPT_REXMITFLG", base.HEX, flag_state_select, 0x20)
fields.srt_opt_stream = ProtoField.uint32("srt_dev.srt_opt_stream", "SRT_OPT_STREAM", base.HEX, flag_state_select, 0x40)
-- ACK fields
fields.last_ack_pack = ProtoField.uint32("srt_dev.last_ack_pack", "Last ACK Packet Sequence Number", base.DEC)
fields.rtt = ProtoField.int32("srt_dev.rtt", "Round Trip Time", base.DEC)
fields.rtt_variance = ProtoField.int32("srt_dev.rtt_variance", "Round Trip Time Variance", base.DEC)
fields.buf_size = ProtoField.uint32("srt_dev.buf_size", "Available Buffer Size", base.DEC)
fields.pack_rcv_rate = ProtoField.uint32("srt_dev.pack_rcv_rate", "Packet Receiving Rate", base.DEC)
fields.est_link_capacity = ProtoField.uint32("srt_dev.est_link_capacity", "Estimated Link Capacity", base.DEC)
fields.rcv_rate = ProtoField.uint32("srt_dev.rcv_rate", "Receiving Rate", base.DEC)
-- ACKACK fields
fields.ack_num = ProtoField.uint32("srt_dev.ack_num", "ACK number", base.DEC)
fields.ctl_info = ProtoField.uint32("srt_dev.ctl_info", "Control Information", base.DEC)
-- KMRSP fields
local srt_km_state_select = {
[0] = "[SRT_KM_UNSECURED]",
[1] = "[SRT_KM_SECURING]",
[2] = "[SRT_KM_SECURED]",
[3] = "[SRT_KM_NOSECRET]",
[4] = "[SRT_KM_BADSECRET]"
}
fields.km_err = ProtoField.uint32("srt_dev.km_err", "Key Message Error", base.HEX, srt_km_state_select, 0xF)
-- NAK Control Packet fields
fields.lost_list_tree = ProtoField.none("srt_dev.lost_list_tree", "Lost Packet List", base.NONE)
fields.lost_pack_seq = ProtoField.uint32("srt_dev.lost_pack_seq", "Lost Packet Sequence Number", base.DEC)
fields.lost_pack_range_tree = ProtoField.none("srt_dev.lost_pack_range_tree", "Lost Packet Range", base.NONE)
fields.lost_start = ProtoField.uint32("srt_dev.lost_start", "Lost Starting Sequence", base.DEC)
fields.lost_up_to = ProtoField.uint32("srt_dev.lost_up_to", "Lost Up To(including)", base.DEC)
-- Dissect packet
function srt_dev.dissector (tvb, pinfo, tree)
-- Packet is based on UDP, so the data can be processed directly after UDP
local subtree = tree:add(srt_dev, tvb())
local offset = 0
-- Changes the protocol name
pinfo.cols.protocol = srt_dev.name
-- Take out the first bit of package
-- 0 -> Data Packet
-- 1 -> Control Packet
local typebit = bit.rshift(tvb(offset, 1):uint(), 7)
pack_type_tree = subtree:add(fields.pack_type_tree, tvb(offset, 4))
if typebit == 1 then
-- Handle Control Packet
pack_type_tree:add(fields.pack_type, tvb(offset, 2))
local msg_type = tvb(offset, 2):uint()
if msg_type ~= 0xFFFF then
-- If type field isn't '0x7FFF',it means packet is normal data packet, then handle type field
msg_type = bit.band(msg_type, 0x7FFF)
function parse_three_param()
-- Ignore Additional Info (this field is not defined in this packet type)
subtree:add(fields.additional_info, tvb(offset, 4)):append_text(" [undefined]")
offset = offset + 4
-- Handle Time Stamp
subtree:add(fields.time_stamp, tvb(offset, 4)):append_text(" μs")
offset = offset + 4
-- Handle Destination Socket
subtree:add(fields.dst_sock, tvb(offset, 4))
offset = offset + 4
end
local switch = {
[0] = function()
pinfo.cols.info:append(" [HANDSHAKE]")
pack_type_tree:append_text(" [HANDSHAKE]")
pack_type_tree:add(fields.msg_type, tvb(offset, 2))
pack_type_tree:add(fields.reserve, tvb(offset + 2, 2)):append_text(" [Undefined]")
offset = offset + 4
-- Handle Additional Info, Timestamp and Destination Socket
parse_three_param()
-- Handle UDT version field
local UDT_version = tvb(offset, 4):uint()
subtree:add(fields.UDT_version, tvb(offset, 4))
offset = offset + 4
if UDT_version == 4 then
-- UDT version is 4, packet is different from UDT version 5
-- Handle sock type
local sock_type = tvb(offset, 4):uint()
if sock_type == 1 then
subtree:add(fields.sock_type, tvb(offset, 4)):append_text(" [SRT_STREAM]")
elseif sock_type == 2 then
subtree:add(fields.sock_type, tvb(offset, 4)):append_text(" [SRT_DRAGAM]")
end
offset = offset + 4
elseif UDT_version == 5 then
-- Handle Encryption Field
local encr_fld = tvb(offset, 2):int()
if encr_fld == 0 then
subtree:add(fields.ency_fld, tvb(offset, 2)):append_text(" (PBKEYLEN not advertised)")
elseif encr_fld == 2 then
subtree:add(fields.ency_fld, tvb(offset, 2)):append_text(" (AES-128)")
elseif encr_fld == 3 then
subtree:add(fields.ency_fld, tvb(offset, 2)):append_text(" (AES-192)")
else
subtree:add(fields.ency_fld, tvb(offset, 2)):append_text(" (AES-256)")
end
offset = offset + 2
-- Handle Extension Field
local ext_fld = tvb(offset, 2):int()
if ext_fld == 0x4A17 then
subtree:add(fields.ext_fld, tvb(offset, 2)):append_text(" [HSv5 MAGIC]")
else
-- Extension Field is HS_EXT_prefix
-- The define is in fiel handshake.h
local ext_fld_tree = subtree:add(fields.ext_fld_tree, tvb(offset, 2))
local str_table = { " [" }
ext_fld_tree:add(fields.hsreq, tvb(offset, 2))
if bit.band(tvb(offset, 2):uint(), 0x1) == 1 then
table.insert(str_table, "HS_EXT_HSREQ")
table.insert(str_table, " | ")
end
ext_fld_tree:add(fields.kmreq, tvb(offset, 2)):append_text(" [HS_EXT_KMREQ]")
if bit.band(tvb(offset, 2):uint(), 0x2) == 2 then
table.insert(str_table, "HS_EXT_KMREQ")
table.insert(str_table, " | ")
end
ext_fld_tree:add(fields.config, tvb(offset, 2)):append_text(" [HS_EXT_CONFIG]")
if bit.band(tvb(offset, 2):uint(), 0x4) == 4 then
table.insert(str_table, "HS_EXT_CONFIG")
table.insert(str_table, " | ")
end
table.remove(str_table)
table.insert(str_table, "]")
if ext_fld ~= 0 then
ext_fld_tree:append_text(table.concat(str_table))
end
end
offset = offset + 2
end
-- Handle Initial packet sequence number
subtree:add(fields.isn, tvb(offset, 4))
offset = offset + 4
-- Handle Maximum Packet Size
subtree:add(fields.mss, tvb(offset, 4))
offset = offset + 4
-- Handle Maximum Flow Window Size
subtree:add(fields.fc, tvb(offset, 4))
offset = offset + 4
-- Handle Connection Type
local conn_type = tvb(offset, 4):int()
local conn_type_tree = subtree:add(fields.conn_type, tvb(offset, 4))
if conn_type == 0 then
conn_type_tree:append_text(" [WAVEAHAND] (Rendezvous Mode)")
pinfo.cols.info:append(" [WAVEAHAND] (Rendezvous Mode)")
elseif conn_type == 1 then
conn_type_tree:append_text(" [INDUCTION]")
elseif conn_type == -1 then
conn_type_tree:append_text(" [CONCLUSION]")
elseif conn_type == -2 then
conn_type_tree:append_text(" [AGREEMENT] (Rendezvous Mode)")
pinfo.cols.info:append(" [AGREEMENT] (Rendezvous Mode)")
end
offset = offset + 4
-- Handle Socket ID
subtree:add(fields.sock_id, tvb(offset, 4))
offset = offset + 4
-- Handle SYN cookie
local syn_cookie = tvb(offset, 4):int()
subtree:add(fields.syn_cookie, tvb(offset, 4))
if syn_cookie == 0 then
conn_type_tree:append_text(" (Caller to Listener)")
pinfo.cols.info:append(" (Caller to Listener)")
else
if conn_type == 1 then
-- reports cookie from listener
conn_type_tree:append_text(" (Listener to Caller)")
pinfo.cols.info:append(" (Listener to Caller)")
end
end
offset = offset + 4
-- Handle Peer IP address
-- Note the network byte order
local the_last_96_bits = 0
the_last_96_bits = the_last_96_bits + math.floor(tvb(offset + 4, 4):int() * (2 ^ 16))
the_last_96_bits = the_last_96_bits + math.floor(tvb(offset + 8, 4):int() * (2 ^ 8))
the_last_96_bits = the_last_96_bits + tvb(offset + 12, 4):int()
if the_last_96_bits == 0 then
subtree:add_le(fields.peer_ipaddr_4, tvb(offset, 4))
else
subtree:add_le(fields.peer_ipaddr, tvb(offset, 16))
end
offset = offset + 16
-- UDT version is 4, packet handle finish
if UDT_version == 4 or offset == tvb:len() then
return
end
function process_ext_type()
-- Handle Ext Type, processing by type
local ext_type = tvb(offset, 2):int()
if ext_type == 1 or ext_type == 2 then
local ext_type_msg_tree = subtree:add(fields.ext_type_msg_tree, tvb(offset, 16))
if ext_type == 1 then
ext_type_msg_tree:append_text(" [SRT_CMD_HSREQ]")
ext_type_msg_tree:add(fields.ext_type, tvb(offset, 2))
conn_type_tree:append_text(" (Caller to Listener)")
pinfo.cols.info:append(" (Caller to Listener)")
else
ext_type_msg_tree:append_text(" [SRT_CMD_HSRSP]")
ext_type_msg_tree:add(fields.ext_type, tvb(offset, 2))
conn_type_tree:append_text(" (Listener to Caller)")
pinfo.cols.info:append(" (Listener to Caller)")
end
offset = offset + 2
-- Handle Ext Size
ext_type_msg_tree:add(fields.ext_size, tvb(offset, 2))
offset = offset + 2
-- Handle SRT Version
ext_type_msg_tree:add(fields.srt_version, tvb(offset, 4))
offset = offset + 4
-- Handle SRT Flags
local SRT_flags_tree = ext_type_msg_tree:add(fields.srt_flags, tvb(offset, 4))
SRT_flags_tree:add(fields.srt_opt_tsbpdsnd, tvb(offset, 4))
SRT_flags_tree:add(fields.srt_opt_tsbpdrcv, tvb(offset, 4))
SRT_flags_tree:add(fields.srt_opt_haicrypt, tvb(offset, 4))
SRT_flags_tree:add(fields.srt_opt_tlpktdrop, tvb(offset, 4))
SRT_flags_tree:add(fields.srt_opt_nakreport, tvb(offset, 4))
SRT_flags_tree:add(fields.srt_opt_rexmitflg, tvb(offset, 4))
SRT_flags_tree:add(fields.srt_opt_stream, tvb(offset, 4))
offset = offset + 4
-- Handle Recv TsbPd Delay and Snd TsbPd Delay
if UDT_version == 4 then
ext_type_msg_tree:add(fields.tsbpd_delay, tvb(offset, 2)):append_text(" [Unused in HSv4]")
offset = offset + 2
ext_type_msg_tree:add(fields.tsbpb_delay, tvb(offset, 2))
offset = offset + 2
else
ext_type_msg_tree:add(fields.rcv_tsbpd_delay, tvb(offset, 2))
offset = offset + 2
ext_type_msg_tree:add(fields.snd_tsbpd_delay, tvb(offset, 2))
offset = offset + 2
end
elseif ext_type == 3 or ext_type == 4 then
local ext_type_msg_tree = subtree:add(fields.ext_type_msg_tree, tvb(offset, 16))
if ext_type == 3 then
ext_type_msg_tree:append_text(" [SRT_CMD_KMREQ]")
ext_type_msg_tree:add(fields.ext_type, tvb(offset, 2))
conn_type_tree:append_text(" (Listener to Caller)")
else
ext_type_msg_tree:append_text(" [SRT_CMD_KMRSP]")
ext_type_msg_tree:add(fields.ext_type, tvb(offset, 2))
end
offset = offset + 2
-- Handle Ext Size
local km_len = tvb(offset, 2):uint()
ext_type_msg_tree:add(fields.ext_size, tvb(offset, 2)):append_text(" (byte/4)")
offset = offset + 2
-- Handle SRT_CMD_KMREQ message
-- V and PT status flag
ext_type_msg_tree:add(fields.V_state, tvb(offset, 1))
ext_type_msg_tree:add(fields.PT_state, tvb(offset, 1))
offset = offset + 1
-- Handle sign
ext_type_msg_tree:add(fields.sign, tvb(offset, 2)):append_text(" (/'HAI/' PnP Vendor ID in big endian order)")
offset = offset + 2
-- Handle resv
ext_type_msg_tree:add(fields.resv, tvb(offset, 1))
-- Handle KK flag
local KK = tvb(offset, 1):uint()
ext_type_msg_tree:add(fields.ext_KK_state, tvb(offset, 1))
offset = offset + 1
-- Handle KEKI
if tvb(offset, 4):uint() == 0 then
ext_type_msg_tree:add(fields.KEKI, tvb(offset, 4)):append_text(" (Default stream associated key(stream/system default))")
else
ext_type_msg_tree:add(fields.KEKI, tvb(offset, 4)):append_text(" (Reserved for manually indexed keys)")
end
offset = offset + 4
-- Handle Cipher
local cipher_node = ext_type_msg_tree:add(fields.cipher, tvb(offset, 1))
local cipher = tvb(offset, 1):uint()
if cipher == 0 then
elseif cipher == 1 then
cipher_node:append_text(" (AES-ECB(potentially for VF 2.0 compatible message))")
elseif cipher == 2 then
cipher_node:append_text(" (AES-CTR[FP800-38A])")
else
cipher_node:append_text(" (AES-CCM or AES-GCM)")
end
offset = offset + 1
-- Handle Auth
if tvb(offset, 1):uint() == 0 then
ext_type_msg_tree:add(fields.auth, tvb(offset, 1)):append_text(" (None or KEKI indexed crypto context)")
else
ext_type_msg_tree:add(fields.auth, tvb(offset, 1))
end
offset = offset + 1
-- Handle SE
local SE_node = ext_type_msg_tree:add(fields.SE, tvb(offset, 1))
local SE = tvb(offset, 1):uint()
if SE == 0 then
SE_node:append_text( " (Unspecified or KEKI indexed crypto context)")
elseif SE == 1 then
SE_node:append_text( " (MPEG-TS/UDP)")
elseif SE == 2 then
SE_node:append_text( " (MPEG-TS/SRT)")
end
offset = offset + 1
-- Handle resv1
ext_type_msg_tree:add(fields.resv1, tvb(offset, 1))
offset = offset + 1
-- Handle resv2
ext_type_msg_tree:add(fields.resv2, tvb(offset, 2))
offset = offset + 2
-- Handle slen
ext_type_msg_tree:add(fields.slen, tvb(offset, 1))
offset = offset + 1
-- Handle klen
local klen = tvb(offset, 1):uint()
ext_type_msg_tree:add(fields.klen, tvb(offset, 1))
offset = offset + 1
-- Handle salt key
ext_type_msg_tree:add(fields.salt, tvb(offset, slen * 4))
offset = offset + slen * 4
-- Handle wrap
-- Handle ICV
local wrap_len = 8 + KK * klen
local wrap_tree = ext_type_msg_tree:add(fields.wrap, tvb(offset, wrap_len))
wrap_tree:add(fields.ICV, tvb(offset, 8))
offset = offset + 8
-- If KK == 2, first key is Even key
if KK == 2 then
wrap_tree:add(fields.even_key, tvb(offset, klen))
offset = offset + klen;
end
-- Handle Odd key
wrap_tree:add(fields.odd_key, tvb(offset, klen))
offset = offset + klen;
elseif ext_type >= 5 and ext_type <= 8 then
local value_size = tvb(offset + 2, 2):uint() * 4
local ext_msg_size = 2 + 2 + value_size
local type_array = { " [SRT_CMD_SID]", " [SRT_CMD_CONGESTION]", " [SRT_CMD_FILTER]", " [SRT_CMD_GROUP]" }
local field_array = { fields.sid, fields.congestion, fields.filter, fields.group }
local ext_type_msg_tree = subtree:add(fields.ext_type_msg_tree, tvb(offset, ext_msg_size)):append_text(type_array[ext_type - 4])
ext_type_msg_tree:add(fields.ext_type, tvb(offset, 2))
offset = offset + 2
-- Handle Ext Msg Value Size
ext_type_msg_tree:add(fields.ext_size, tvb(offset, 2)):append_text(" (byte/4)")
offset = offset + 2
-- Value
local value_table = {}
for pos = 0, value_size - 4, 4 do
table.insert(value_table, string.char(tvb(offset + pos + 3, 1):uint()))
table.insert(value_table, string.char(tvb(offset + pos + 2, 1):uint()))
table.insert(value_table, string.char(tvb(offset + pos + 1, 1):uint()))
table.insert(value_table, string.char(tvb(offset + pos, 1):uint()))
end
local value = table.concat(value_table)
ext_type_msg_tree:add(field_array[ext_type - 4], tvb(offset, value_size), value)
offset = offset + value_size
elseif ext_type == -1 then
local ext_type_msg_tree = subtree:add(fields.ext_type_msg_tree, tvb(offset, tvb:len() - offset)):append_text(" [SRT_CMD_NONE]")
ext_type_msg_tree:add(fields.ext_type, tvb(offset, 2))
offset = offset + 2
-- none
if offset == tvb:len() then
return
end
ext_type_msg_tree:add(fields.none, tvb(offset, tvb:len() - offset))
offset = tvb:len()
end
if offset == tvb:len() then
return
else
process_ext_type()
end
end
process_ext_type()
end,
[1] = function()
pinfo.cols.info:append(" [KEEPALIVE]")
pack_type_tree:append_text(" [KEEPALIVE]")
pack_type_tree:add(fields.msg_type, tvb(offset, 2)):append_text(" [KEEPALIVE]")
pack_type_tree:add(fields.reserve, tvb(offset + 2, 2)):append_text(" [Undefined]")
offset = offset + 4
-- Handle Additional Info, Time Stamp and Destination Socket
parse_three_param()
end,
[2] = function()
pinfo.cols.info:append(" [ACK]")
pack_type_tree:append_text(" [ACK]")
pack_type_tree:add(fields.msg_type, tvb(offset, 2))
pack_type_tree:add(fields.reserve, tvb(offset + 2, 2)):append_text(" [Undefined]")
offset = offset + 4
-- Handle ACK Number
subtree:add(fields.ack_num, tvb(offset, 4))
offset = offset + 4
-- Handle Time Stamp
subtree:add(fields.time_stamp, tvb(offset, 4)):append_text(" μs")
offset = offset + 4
-- Handle Destination Socket
subtree:add(fields.dst_sock, tvb(offset, 4))
offset = offset + 4
-- Handle Last Ack Packet Sequence
local last_ack_pack = tvb(offset, 4):uint()
pinfo.cols.info:append(" (Last ACK Seq:" .. last_ack_pack .. ")")
subtree:add(fields.last_ack_pack, tvb(offset, 4))
offset = offset + 4
-- Handle RTT
local rtt = tvb(offset, 4):int()
subtree:add(fields.rtt, tvb(offset, 4)):append_text(" μs")
offset = offset + 4
-- Handle RTT variance
if rtt < 0 then
subtree:add(fields.rtt_variance, tvb(offset, 4), -tvb(offset, 4):int())
else
subtree:add(fields.rtt_variance, tvb(offset, 4))
end
offset = offset + 4
-- Handle Available Buffer Size(pkts)
subtree:add(fields.buf_size, tvb(offset, 4)):append_text(" pkts")
offset = offset + 4
-- Handle Packets Receiving Rate(Pkts/sec)
subtree:add(fields.pack_rcv_rate, tvb(offset, 4)):append_text(" pkts/sec")
offset = offset + 4
-- Handle Estmated Link Capacity
subtree:add(fields.est_link_capacity, tvb(offset, 4)):append_text(" pkts/sec")
offset = offset + 4
-- Handle Receiving Rate(bps)
subtree:add(fields.rcv_rate, tvb(offset, 4)):append_text(" bps")
offset = offset + 4
end,
[3] = function()
pinfo.cols.info:append(" [NAK(loss Report)]")
pack_type_tree:append_text(" [NAK(loss Report)]")
pack_type_tree:add(fields.msg_type, tvb(offset, 2))
pack_type_tree:add(fields.reserve, tvb(offset + 2, 2)):append_text(" [Undefined]")
offset = offset + 4
-- Handle Additional Info, Timestamp and Destination Socket
parse_three_param()
-- Handle lost packet sequence
-- lua does not support changing loop variables within loops, but in the form of closures
-- https://blog.csdn.net/Ai102iA/article/details/75371239
local start = offset
local ending = tvb:len()
local lost_list_tree = subtree:add(fields.lost_list_tree, tvb(offset, ending - offset))
for start in function()
local first_bit = bit.rshift(tvb(start, 1):uint(), 7)
if first_bit == 1 then
local lost_pack_range_tree = lost_list_tree:add(fields.lost_pack_range_tree, tvb(start, 8))
local lost_start = bit.band(tvb(start, 4):uint(), 0x7FFFFFFF)
lost_pack_range_tree:append_text(" (" .. lost_start .. " -> " .. tvb(start + 4, 4):uint() .. ")")
lost_pack_range_tree:add(fields.lost_start, tvb(start, 4), lost_start)
start = start + 4
lost_pack_range_tree:add(fields.lost_up_to, tvb(start, 4))
start = start + 4
else
lost_list_tree:add(fields.lost_pack_seq, tvb(start, 4))
start = start + 4
end
return start
end
do
if start == ending then
break
end
end
end,
[4] = function()
pinfo.cols.info:append(" [Congestion Warning]")
pack_type_tree:append_text(" [Congestion Warning]")
pack_type_tree:add(fields.msg_type, tvb(offset, 2))
pack_type_tree:add(fields.reserve, tvb(offset + 2, 2)):append_text(" [Undefined]")
offset = offset + 4
end,
[5] = function()
pinfo.cols.info:append(" [Shutdown]")
pack_type_tree:append_text(" [Shutdown]")
pack_type_tree:add(fields.msg_type, tvb(offset, 2))
pack_type_tree:add(fields.reserve, tvb(offset + 2, 2)):append_text(" [Undefined]")
offset = offset + 4
-- Handle Additional Info, Timestamp and Destination Socket
parse_three_param()
end,
[6] = function()
pinfo.cols.info:append(" [ACKACK]")
pack_type_tree:append_text(" [ACKACK]")
pack_type_tree:add(fields.msg_type, tvb(offset, 2))
pack_type_tree:add(fields.reserve, tvb(offset + 2, 2)):append_text(" [Undefined]")
offset = offset + 4
-- Handle ACK sequence number
subtree:add(fields.ack_num, tvb(offset, 4))
offset = offset + 4
-- Handle Time Stamp
subtree:add(fields.time_stamp, tvb(offset, 4)):append_text(" μs")
offset = offset + 4
-- Handle Destination Socket
subtree:add(fields.dst_sock, tvb(offset, 4))
offset = offset + 4
-- Handle Control Information
subtree:add(fields.ctl_info, tvb(offset, 4))
offset = offset + 4
end,
[7] = function()
pinfo.cols.info:append(" [Drop Request]")
pack_type_tree:append_text(" [Drop Request]")
pack_type_tree:add(fields.msg_type, tvb(offset, 2)):append_text(" [Drop Request]")
pack_type_tree:add(fields.reserve, tvb(offset + 2, 2)):append_text(" [Undefined]")
offset = offset + 4
end,
[8] = function()
pinfo.cols.info:append(" [Peer Error]")
pack_type_tree:append_text(" [Peer Error]")
pack_type_tree:add(fields.msg_type, tvb(offset, 2)):append_text(" [Peer Error]")
pack_type_tree:add(fields.reserve, tvb(offset + 2, 2)):append_text(" [Undefined]")
offset = offset + 4
end
}
-- Handle based on msg_type
local case = switch[msg_type]
if case then
case()
else
-- default case
subtree:add(fields.msg_type, tvb(offset, 2)):append_text(" [Unknown Message Type]")
offset = offset + 4
end
else
-- If type field is '0x7FFF', it means an extended type, Handle Reserve field
offset = offset + 2
local msg_ext_type = tvb(offset, 2):uint()
if msg_ext_type == 0 then
pinfo.cols.info:append(" [Message Extension]")
pack_type_tree:add(fields.msg_ext_type, tvb(offset, 2)):append_text(" [Message Extension]")
offset = offset + 2
-- Handle Additional Info, Time Stamp and Destination Socket
parse_three_param()
-- Control information: defined by user
elseif msg_ext_type == 1 or ext_type == 2 then
if msg_ext_type == 1 then
pack_type_tree:add(fields.msg_ext_type, tvb(offset, 2)):append_text(" [SRT Handshake Request]")
pinfo.cols.info:append(" [SRT Handshake Request]")
elseif msg_ext_type == 2 then
pack_type_tree:add(fields.msg_ext_type, tvb(offset, 2)):append_text(" [SRT Handshake Response]")
pinfo.cols.info:append(" [SRT Handshake Response]")
end
offset = offset + 2
-- Ignore additional info (this field is not defined in this packet type)
subtree:add(fields.additional_info, tvb(offset, 4)):append_text(" [undefined]")
offset = offset + 4
-- Handle Time Stamp
subtree:add(fields.time_stamp, tvb(offset, 4)):append_text("μs")
offset = offset + 4
-- Handle Destination Socket
subtree:add(fields.dst_sock, tvb(offset, 4))
offset = offset + 4
-- Handle SRT Version field
subtree:add(fields.srt_version, tvb(offset, 4))
offset = ofssset + 4
-- Handle SRT Flags
local SRT_flags_tree = subtree:add(fields.srt_flags, tvb(offset, 4))
SRT_flags_tree:add(fields.srt_opt_tsbpdsnd, tvb(offset, 4))
SRT_flags_tree:add(fields.srt_opt_tsbpdrcv, tvb(offset, 4))
SRT_flags_tree:add(fields.srt_opt_haicrypt, tvb(offset, 4))
SRT_flags_tree:add(fields.srt_opt_tlpktdrop, tvb(offset, 4))
SRT_flags_tree:add(fields.srt_opt_nakreport, tvb(offset, 4))
SRT_flags_tree:add(fields.srt_opt_rexmitflg, tvb(offset, 4))
SRT_flags_tree:add(fields.srt_opt_stream, tvb(offset, 4))
offset = offset + 4
-- Handle TsbPd Resv
subtree:add(fields.tsbpb_resv, tvb(offset, 2))
offset = offset + 2
-- Handle TsbPb Delay
subtree:add(fields.tsbpb_delay, tvb(offset, 2))
offset = offset + 2
-- Handle Reserved field
subtree:add(fields.reserve, tvb(offset, 4))
offset = offset + 4
elseif msg_ext_type == 3 or msg_ext_type == 4 then
if msg_ext_type == 3 then
pack_type_tree:add(fields.msg_ext_type, tvb(offset, 2)):append_text(" [Encryption Keying Material Request]")
pinfo.cols.info:append(" [Encryption Keying Material Request]")
elseif msg_ext_type == 4 then
pack_type_tree:add(fields.msg_ext_type, tvb(offset, 2)):append_text(" [Encryption Keying Material Response]")
pinfo.cols.info:append(" [Encryption Keying Material Response]")
end
offset = offset + 2
-- Ignore additional info (this field is not defined in this packet type)
subtree:add(fields.additional_info, tvb(offset, 4)):append_text(" [undefined]")
offset = offset + 4
-- Handle Timestamp
subtree:add(fields.time_stamp, tvb(offset, 4)):append_text("μs")
offset = offset + 4
-- Handle Destination Socket
subtree:add(fields.dst_sock, tvb(offset, 4))
offset = offset + 4
-- Handle KmErr
if msg_ext_type == 4 then
subtree:add(fields.km_err, tvb(offset, 4))
offset = offset + 4
return
end
-- The encrypted message is not handled
end
end
else
-- 0 -> Data Packet
pack_type_tree:add(fields.pack_type, tvb(offset, 2))
pack_type_tree:append_text(" (Data Packet)")
local seq_num = tvb(offset, 4):uint()
pinfo.cols.info:append(" (Data Packet)(Seq Num:" .. seq_num .. ")")
-- The first 4 bytes are the package sequence number
subtree:add(fields.seq_num, tvb(offset, 4))
offset = offset + 4
data_flag_info_tree = subtree:add(fields.data_flag_info_tree, tvb(offset, 1))
-- Handle FF flag
local FF_state = bit.rshift(bit.band(tvb(offset, 1):uint(), 0xC0), 6)
if FF_state == 0 then
data_flag_info_tree:append_text(" [Middle packet]")
elseif FF_state == 1 then
data_flag_info_tree:append_text(" [Last packet]")
elseif FF_state == 2 then
data_flag_info_tree:append_text(" [First packet]")
else
data_flag_info_tree:append_text(" [Single packet]")
end
data_flag_info_tree:add(fields.FF_state, tvb(offset, 1))
-- Handle O flag
local O_state = bit.rshift(bit.band(tvb(offset, 1):uint(), 0x20), 5)
if O_state == 0 then
data_flag_info_tree:append_text(" [Data delivered unordered]")
else
data_flag_info_tree:append_text(" [Data delivered in order]")
end
data_flag_info_tree:add(fields.O_state, tvb(offset, 1))
-- Handle KK flag
local KK_state = bit.rshift(bit.band(tvb(offset, 1):uint(), 0x18), 3)
if KK_state == 1 then
data_flag_info_tree:append_text(" [Encrypted with even key]")
elseif KK_state == 2 then
data_flag_info_tree:append_text(" [Encrypted with odd key]")
end
data_flag_info_tree:add(fields.KK_state, tvb(offset, 1))
-- Handle R flag
local R_state = bit.rshift(bit.band(tvb(offset, 1):uint(), 0x04), 2)
if R_state == 1 then
data_flag_info_tree:append_text(" [Retransmit packet]")
pinfo.cols.info:append(" [Retransmit packet]")
end
data_flag_info_tree:add(fields.R_state, tvb(offset, 1))
-- Handle message number
local msg_num = tvb(offset, 4):uint()
msg_num = bit.band(tvb(offset, 4):uint(), 0x03FFFFFF)
-- subtree:add(fields.msg_num, bit.band(tvb(offset, 4):uint(), 0x03FFFFFF))
subtree:add(fields.msg_num, tvb(offset, 4), msg_num)
offset = offset + 4
-- Handle Timestamp
subtree:add(fields.time_stamp, tvb(offset, 4)):append_text(" μs")
offset = offset + 4
-- Handle destination socket
subtree:add(fields.dst_sock, tvb(offset, 4))
offset = offset + 4
end
end
-- Add the protocol into udp table
local port = 1935
local function enable_dissector()
DissectorTable.get("udp.port"):add(port, srt_dev)
end
-- Call it now - enabled by default
enable_dissector()
local function disable_dissector()
DissectorTable.get("udp.port"):remove(port, srt_dev)
end
-- Prefs changed will listen at new port
function srt_dev.prefs_changed()
if port ~= srt_dev.prefs.srt_udp_port then
if port ~= 0 then
disable_dissector()
end
port = srt_dev.prefs.srt_udp_port
if port ~= 0 then
enable_dissector()
end
end
end
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