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Handle variable length question section. #29

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Handle variable length question section. #29

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42 changes: 24 additions & 18 deletions packet.js
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Original file line number Diff line number Diff line change
Expand Up @@ -169,9 +169,8 @@ function writeHeader(buff, packet) {
val += (packet.header.res3 << 4) & 0x10;
val += packet.header.rcode & 0xF;
buff.writeUInt16BE(val & 0xFFFF);
assert(packet.question.length == 1, 'DNS requires one question');
// aren't used
buff.writeUInt16BE(1);
// question offset 4
buff.writeUInt16BE(packet.question.length & 0xFFFF);
// answer offset 6
buff.writeUInt16BE(packet.answer.length & 0xFFFF);
// authority offset 8
Expand Down Expand Up @@ -233,7 +232,7 @@ function writeQuestion(buff, val, label_index) {
namePack(val.name, buff, label_index);
buff.writeUInt16BE(val.type & 0xFFFF);
buff.writeUInt16BE(val.class & 0xFFFF);
return WRITE_RESOURCE_RECORD;
return WRITE_QUESTION;
}

function writeResource(buff, val, label_index, rdata) {
Expand Down Expand Up @@ -390,7 +389,7 @@ Packet.write = function(buff, packet) {
var state = WRITE_HEADER,
val,
section,
count,
count = 0,
rdata,
last_resource,
label_index = {};
Expand All @@ -416,9 +415,14 @@ Packet.write = function(buff, packet) {
state = writeTruncate(buff, packet, section, last_resource);
break;
case WRITE_QUESTION:
state = writeQuestion(buff, packet.question[0], label_index);
section = 'answer';
count = 0;
if (count < packet.question.length) {
state = writeQuestion(buff, packet.question[count], label_index);
count += 1;
} else {
state = WRITE_RESOURCE_RECORD;
section = 'answer';
count = 0;
}
break;
case WRITE_RESOURCE_RECORD:
last_resource = buff.tell();
Expand Down Expand Up @@ -520,15 +524,11 @@ function parseHeader(msg, packet) {
return PARSE_QUESTION;
}

function parseQuestion(msg, packet) {
var val = {};
function parseQuestion(msg, val, packet) {
val.name = nameUnpack(msg);
val.type = msg.readUInt16BE();
val.class = msg.readUInt16BE();
packet.question[0] = val;
assert(packet.question.length === 1);
// TODO handle qdcount > 1 in practice no one sends this
return PARSE_RESOURCE_RECORD;
return PARSE_QUESTION;
}

function parseRR(msg, val, rdata) {
Expand Down Expand Up @@ -686,7 +686,7 @@ Packet.parse = function(msg) {
val,
rdata,
section,
count;
count = 0;

var packet = new Packet();

Expand All @@ -701,9 +701,15 @@ Packet.parse = function(msg) {
state = parseHeader(msg, packet);
break;
case PARSE_QUESTION:
state = parseQuestion(msg, packet);
section = 'answer';
count = 0;
if (count < packet.question.length) {
val = packet.question[count] = {}
state = parseQuestion(msg, val, packet);
count += 1;
} else {
state = PARSE_RESOURCE_RECORD;
section = 'answer';
count = 0;
}
break;
case PARSE_RESOURCE_RECORD:
// console.log('PARSE_RESOURCE_RECORD: count = %d, %s.len = %d', count, section, packet[section].length);
Expand Down