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fixes parser / regex errors while parsing IEC61162-450 / LWE sentences #1

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fixes parser / regex errors while parsing IEC61162-450 / LWE sentences #1

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b4c14c7
replaced pgsub() with lua plaintext string.find(..)
florian-z Feb 3, 2023
9fed42d
allow up to 32 non ascii bytes before ! or $ of nmea-string
florian-z Apr 4, 2023
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36 changes: 20 additions & 16 deletions maritime-modules/heuristic.lua
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Original file line number Diff line number Diff line change
Expand Up @@ -9,22 +9,26 @@ local proto_iec61162450_binary = require "proto.iec61162450binary"
local function nmea_0183_heuristic_checker(buffer, pinfo, tree)
local length = buffer:len()
if length < 12 then return false end

local pattern = "^[!%$]%u%w-%p.-%*[%d%u][%d%u]\r\n"
local nmea_sentence = string.find(buffer():string(), pattern)
if nmea_sentence == nil then
return false
else
local matches, matches_order = parser_nmea:find_nmea_0183(buffer, pinfo)
for _, beg_idx in pairs(matches_order) do
match = matches[beg_idx]
local sub_buff_beg = beg_idx - 1
local sub_buff_len = match:len()
local sub_buffer = buffer(sub_buff_beg, sub_buff_len):tvb()
proto_nmea0183.dissector(sub_buffer, pinfo, tree)
end
return true
end

local cnt = -1
repeat
cnt = cnt + 1

local pattern = "^[!%$]%u%w-%p.-%*[%d%u][%d%u]\r\n"
local nmea_sentence = string.find(buffer:raw(cnt), pattern)
if nmea_sentence ~= nil then
local matches, matches_order = parser_nmea:find_nmea_0183(buffer, pinfo)
for _, beg_idx in pairs(matches_order) do
match = matches[beg_idx]
local sub_buff_beg = beg_idx - 1
local sub_buff_len = match:len()
local sub_buffer = buffer(sub_buff_beg, sub_buff_len):tvb()
proto_nmea0183.dissector(sub_buffer, pinfo, tree)
end
return true
end
until(cnt >= length or cnt > 32)
return false
end

local function iec_61162_450_nmea_heuristic_checker(buffer, pinfo, tree)
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4 changes: 2 additions & 2 deletions maritime-modules/parser/iec450.lua
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Original file line number Diff line number Diff line change
Expand Up @@ -10,7 +10,7 @@ function parser_iec450:find_tags(buffer)
local msg = buffer():string()
local pattern = "^UdPbC\0(\\%w%p.-%*[%d%u][%d%u]\\)[!%$]%u%w-%p.-%*[%d%u][%d%u]\r\n"
local tags = string.match(msg, pattern)
local tags_beg, tags_end = string.find(msg, utilities:pgsub(tags))
local tags_beg, tags_end = string.find(msg, tags, 1, true)
return utilities:offset_length(tags_beg, tags_end)
end

Expand Down Expand Up @@ -50,7 +50,7 @@ function parser_iec450:find_sentence_iec(buffer)
local msg = buffer():string()
local pattern = "^UdPbC\0\\%w%p.-%*[%d%u][%d%u]\\([!%$]%u%w-%p.-%*[%d%u][%d%u]\r\n)"
local sentence = string.match(msg, pattern)
local sentence_beg, sentence_end = string.find(msg, utilities:pgsub(sentence))
local sentence_beg, sentence_end = string.find(msg, sentence, 1, true)
return utilities:offset_length(sentence_beg, sentence_end)
end

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26 changes: 13 additions & 13 deletions maritime-modules/parser/nmea.lua
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Original file line number Diff line number Diff line change
Expand Up @@ -7,57 +7,57 @@ local utilities = require "utilities"
local parser_nmea = {}

function parser_nmea:find_sentence(buffer)
local msg = buffer():string()
local msg = buffer():raw()
local pattern = "([!%$]%u%w-%p.-%*[%d%u][%d%u])\r\n"
local sentence = string.match(buffer(0, -1):string(), pattern)
local sentence_beg, sentence_end = string.find(msg, utilities:pgsub(sentence))
local sentence_beg, sentence_end = string.find(msg, sentence, 1, true)
return utilities:offset_length(sentence_beg, sentence_end)
end

function parser_nmea:find_sentence_load(buffer)
local msg = buffer():string()
local msg = buffer():raw()
local pattern = "[!%$](%u%w-%p.-)%*[%d%u][%d%u]\r\n"
local sentence = string.match(buffer(0, -1):string(), pattern)
local sentence_beg, sentence_end = string.find(msg, utilities:pgsub(sentence))
local sentence_beg, sentence_end = string.find(msg, sentence, 1, true)
return utilities:offset_length(sentence_beg, sentence_end)
end

function parser_nmea:find_talker_id(buffer)
local msg = buffer():string()
local msg = buffer():raw()
local pattern = "[!%$](%u%w-)%p.-%*[%d%u][%d%u]\r\n"
local talker_sentence_ids = string.match(buffer(0, -1):string(), pattern)
local talkerid = talker_sentence_ids:sub(1, -4)
local talk_id_beg, talk_id_end = string.find(msg, utilities:pgsub(talkerid))
local talk_id_beg, talk_id_end = string.find(msg, talkerid, 1, true)
return utilities:offset_length(talk_id_beg, talk_id_end)
end

function parser_nmea:find_sentence_id(buffer)
local msg = buffer():string()
local msg = buffer():raw()
local pattern = "[!%$](%u%w-)%p.-%*[%d%u][%d%u]\r\n"
local talker_sentence_id = string.match(buffer(0, -1):string(), pattern)
local sentenceid = talker_sentence_id:sub(-3, -1)
local sent_id_beg, sent_id_end = string.find(msg, utilities:pgsub(sentenceid))
local sent_id_beg, sent_id_end = string.find(msg, sentenceid, 1, true)
return utilities:offset_length(sent_id_beg, sent_id_end)
end

function parser_nmea:find_data(buffer)
local msg = buffer():string()
local msg = buffer():raw()
local pattern = "[!%$]%u%w-%p(.-)%*[%d%u][%d%u]\r\n"
local data = string.match(buffer(0, -1):string(), pattern)
local data_beg, data_end = string.find(msg, utilities:pgsub(data))
local data_beg, data_end = string.find(msg, data, 1, true)
return utilities:offset_length(data_beg, data_end)
end

function parser_nmea:find_checksum(buffer)
local msg = buffer():string()
local msg = buffer():raw()
local pattern = "[!%$]%u%w-%p.-%*([%d%u][%d%u])\r\n"
local chksm = string.match(buffer(0, -1):string(), pattern)
local chksm_beg, chksm_end = string.find(msg, utilities:pgsub(chksm))
local chksm_beg, chksm_end = string.find(msg, chksm, 1, true)
return utilities:offset_length(chksm_beg, chksm_end)
end

function parser_nmea:find_nmea_0183(buffer, pinfo)
local msg = buffer():string()
local msg = buffer():raw()
local pattern = "[!%$]%u%w-%p.-%*[%d%u][%d%u]\r\n"
local matches = {}
local matches_order = {}
Expand Down
5 changes: 0 additions & 5 deletions maritime-modules/utilities.lua
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Original file line number Diff line number Diff line change
Expand Up @@ -3,11 +3,6 @@ if not _G['maritimedissector'] then return end

local utilities = {}

function utilities:pgsub(str)
local replaced = str:gsub("*", "%%*"):gsub("-", "%%-"):gsub(",", "%%p"):gsub("%.", "%%p"):gsub("?", "%%p"):gsub("+", "%%p")
return replaced
end

function utilities:offset_length(beg_idx, end_idx)
local offset = beg_idx - 1
local length = end_idx - offset
Expand Down