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authorKim Alvefur <zash@zash.se>2020-10-04 21:29:44 +0200
committerKim Alvefur <zash@zash.se>2020-10-04 21:29:44 +0200
commitb657d2ab26259909d97a055a0ddba5f2f6f85d24 (patch)
tree36c363ab612049d2003619020a720a6337f48c87
parent29238183e9fd345cd0e60eeb59cfe179223cc3ea (diff)
downloadprosody-b657d2ab26259909d97a055a0ddba5f2f6f85d24.tar.gz
prosody-b657d2ab26259909d97a055a0ddba5f2f6f85d24.zip
util.dns: Implement SVCB record parser
Based on draft-ietf-dnsop-svcb-https-00
-rw-r--r--util/dns.lua54
1 files changed, 54 insertions, 0 deletions
diff --git a/util/dns.lua b/util/dns.lua
index f086f2c1..851f480e 100644
--- a/util/dns.lua
+++ b/util/dns.lua
@@ -198,6 +198,60 @@ function parsers.TLSA(packet)
}, tlsa_mt);
end
+local svcb_params = {"alpn"; "no-default-alpn"; "port"; "ipv4hint"; "echconfig"; "ipv6hint"};
+setmetatable(svcb_params, {__index = function(_, n) return "key" .. tostring(n); end});
+
+local svcb_mt = {
+ __tostring = function (rr)
+ local kv = {};
+ for i = 1, #rr.fields do
+ t_insert(kv, s_format("%s=%q", svcb_params[rr.fields[i].key], tostring(rr.fields[i].value)));
+ end
+ return s_format("%d %s %s", rr.prio, rr.name, t_concat(kv, " "));
+ end;
+};
+local svbc_ip_mt = {__tostring = function(ip) return t_concat(ip, ", "); end}
+
+function parsers.SVCB(packet)
+ local prio_h, prio_l = packet:byte(1,2);
+ local prio = prio_h*256+prio_l;
+ local name, pos = readDnsName(packet, 3);
+ local fields = {};
+ while #packet > pos do
+ local key_h, key_l = packet:byte(pos+0,pos+1);
+ local len_h, len_l = packet:byte(pos+2,pos+3);
+ local key = key_h*256+key_l;
+ local len = len_h*256+len_l;
+ local value = packet:sub(pos+4,pos+4-1+len)
+ if key == 1 then
+ value = setmetatable(parsers.TXT(value), svbc_ip_mt);
+ elseif key == 3 then
+ local port_h, port_l = value:byte(1,2);
+ local port = port_h*256+port_l;
+ value = port;
+ elseif key == 4 then
+ local ip = {};
+ for i = 1, #value, 4 do
+ t_insert(ip, parsers.A(value:sub(i, i+3)));
+ end
+ value = setmetatable(ip, svbc_ip_mt);
+ elseif key == 6 then
+ local ip = {};
+ for i = 1, #value, 16 do
+ t_insert(ip, parsers.AAAA(value:sub(i, i+15)));
+ end
+ value = setmetatable(ip, svbc_ip_mt);
+ end
+ t_insert(fields, { key = key, value = value, len = len });
+ pos = pos+len+4;
+ end
+ return setmetatable({
+ prio = prio, name = name, fields = fields,
+ }, svcb_mt);
+end
+
+parsers.HTTPS = parsers.SVCB;
+
local params = {
TLSA = {
use = tlsa_usages;