From 8963ad4cd5e7d590bcff34e12638154ad436dce2 Mon Sep 17 00:00:00 2001
From: Tomas Krizek <tomas.krizek@nic.cz>
Date: Thu, 25 Nov 2021 11:43:30 +0100
Subject: [PATCH] lua: add parse_rdata() utility function
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Credit for code goes to Vladimír Čunát
---
 NEWS                |  4 ++++
 daemon/lua/kres.lua | 23 +++++++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/NEWS b/NEWS
index 126615055..6b261155f 100644
--- a/NEWS
+++ b/NEWS
@@ -1,6 +1,10 @@
 Knot Resolver 5.4.3 (2021-mm-dd)
 ================================
 
+Improvements
+------------
+- lua: add kres.parse_rdata() to parse RDATA from string to wire format (!1233)
+
 Bugfixes
 --------
 - policy.rpz: improve logs, fix origin detection in files without $ORIGIN
diff --git a/daemon/lua/kres.lua b/daemon/lua/kres.lua
index 140421660..3b00c2011 100644
--- a/daemon/lua/kres.lua
+++ b/daemon/lua/kres.lua
@@ -328,6 +328,28 @@ local function dname2wire(name)
 	return ffi.string(name, knot.knot_dname_size(name))
 end
 
+-- Parse RDATA, from presentation to wire-format.
+-- in: a table of strings, each a line describing RRTYPE+RDATA
+-- out: a table of RDATA strings in wire-format
+local function parse_rdata(strs, nothing)
+	local zonefile = require('zonefile')
+	if type(strs) ~= 'table' or nothing ~= nil then -- accidents like forgetting braces
+		error('a table of string(s) is expected', 2)
+	end
+	local res = {}
+	for _, line in ipairs(strs) do
+		if type(line) ~= 'string' then
+			error('table must contain strings', 2)
+		end
+		local rrs = zonefile.string('. ' .. line)
+		if #rrs == 0 then error('failed to parse line: ' .. line, 2) end
+		for _, rr in ipairs(rrs) do
+			table.insert(res, rr.rdata)
+		end
+	end
+	return res
+end
+
 -- RR sets created in Lua must have a destructor to release allocated memory
 local function rrset_free(rr)
 	if rr._owner ~= nil then ffi.C.free(rr._owner) end
@@ -1060,6 +1082,7 @@ kres = {
 	end,
 	dname2str = dname2str,
 	dname2wire = dname2wire,
+	parse_rdata = parse_rdata,
 
 	rr2str = rr2str,
 	str2ip = function (ip)
-- 
2.47.3