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680 lines (604 loc) · 18.7 KB
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/******************************************************************************/
/* pcap.js -- represent a pcap file
*
* Copyright 2012-2016 AOL Inc. All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this Software except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*jshint
node: true, plusplus: false, curly: true, eqeqeq: true, immed: true, latedef: true, newcap: true, nonew: true, undef: true, strict: true, trailing: true
*/
'use strict';
var fs = require('fs-ext');
var Pcap = module.exports = exports = function Pcap (key) {
this.key = key;
this.count = 0;
this.closing = false;
return this;
};
var internals = {
pr2name: {
1: "icmp",
6: "tcp",
17: "udp",
47: "gre",
58: "icmpv6"
},
pcaps: {}
};
//////////////////////////////////////////////////////////////////////////////////
//// High Level
//////////////////////////////////////////////////////////////////////////////////
Pcap.prototype.ref = function() {
this.count++;
};
exports.get = function(key) {
if (internals.pcaps[key]) {
return internals.pcaps[key];
}
var pcap = new Pcap(key);
internals.pcaps[key] = pcap;
return pcap;
};
exports.make = function(key, header) {
var pcap = new Pcap(key);
pcap.headBuffer = header;
pcap.bigEndian = pcap.headBuffer.readUInt32LE(0) === 0xd4c3b2a1;
if (pcap.bigEndian) {
pcap.linkType = pcap.headBuffer.readUInt32BE(20);
} else {
pcap.linkType = pcap.headBuffer.readUInt32LE(20);
}
return pcap;
}
Pcap.prototype.isOpen = function() {
return this.fd !== undefined;
};
Pcap.prototype.open = function(filename) {
if (this.fd) {
return;
}
this.filename = filename;
this.fd = fs.openSync(filename, "r");
this.readHeader();
};
Pcap.prototype.openReadWrite = function(filename) {
if (this.fd) {
return;
}
this.filename = filename;
this.fd = fs.openSync(filename, "r+");
};
Pcap.prototype.unref = function() {
this.count--;
if (this.count > 0) {
return;
}
if (this.closing === true) {
return;
}
var self = this;
self.closing = true;
setTimeout(function() {
if (self.closing && self.count === 0) {
delete internals.pcaps[self.key];
if (self.fd) {
fs.close(self.fd);
}
delete self.fd;
} else {
self.closing = false;
}
}, 500);
};
Pcap.prototype.readHeader = function(cb) {
if (this.headBuffer) {
if (cb) {
cb(this.headBuffer);
}
return this.headBuffer;
}
this.headBuffer = new Buffer(24);
fs.readSync(this.fd, this.headBuffer, 0, 24, 0);
this.bigEndian = this.headBuffer.readUInt32LE(0) === 0xd4c3b2a1;
if (this.bigEndian) {
this.linkType = this.headBuffer.readUInt32BE(20);
} else {
this.linkType = this.headBuffer.readUInt32LE(20);
}
if (cb) {
cb(this.headBuffer);
}
return this.headBuffer;
};
Pcap.prototype.readPacket = function(pos, cb) {
var self = this;
// Hacky!! File isn't actually opened, try again soon
if (!self.fd) {
setTimeout(self.readPacket, 10, pos, cb);
return;
}
var buffer = new Buffer(1550);
try {
// Try and read full packet and header in one read
fs.read(self.fd, buffer, 0, buffer.length, pos, function (err, bytesRead, buffer) {
if (bytesRead < 16) {
return cb(null);
}
var len = (self.bigEndian?buffer.readUInt32BE(8):buffer.readUInt32LE(8));
if (len < 0 || len > 0xffff) {
return cb(undefined);
}
// Full packet fit
if (16 + len <= bytesRead) {
return cb(buffer.slice(0,16+len));
}
// Full packet didn't fit, get what was missed
try {
var b = new Buffer(16+len);
buffer.copy(b, 0, 0, bytesRead);
buffer = b;
fs.read(self.fd, buffer, bytesRead, (16+len)-bytesRead, pos+bytesRead, function (err, bytesRead, buffer) {
return cb(buffer.slice(0,16+len));
});
} catch (e) {
console.log("Error ", e, "for file", self.filename);
return cb (null);
}
});
} catch (e) {
console.log("Error ", e, "for file", self.filename);
return cb (null);
}
};
Pcap.prototype.scrubPacket = function(packet, pos, buf, entire) {
var len = packet.pcap.incl_len + 16; // 16 = pcap header length
if (entire) {
pos += 16; // Don't delete pcap header
len -= 16;
} else {
switch(packet.ip.p) {
case 1:
pos += (packet.icmp._pos + 8);
len -= (packet.icmp._pos + 8);
break;
case 6:
pos += (packet.tcp._pos + 4*packet.tcp.off);
len -= (packet.tcp._pos + 4*packet.tcp.off);
break;
case 17:
pos += (packet.udp._pos + 8);
len -= (packet.udp._pos + 8);
break;
default:
throw "Unknown packet type, can't scrub";
}
}
fs.writeSync(this.fd, buf, 0, len, pos);
fs.fsyncSync(this.fd);
};
//////////////////////////////////////////////////////////////////////////////////
//// Utilities
//////////////////////////////////////////////////////////////////////////////////
exports.protocol2Name = function(num) {
return internals.pr2name[num] || "" + num;
};
exports.inet_ntoa = function(num) {
return (num >> 24 & 0xff) + '.' + (num>>16 & 0xff) + '.' + (num>>8 & 0xff) + '.' + (num & 0xff);
};
//////////////////////////////////////////////////////////////////////////////////
//// Decode pcap buffers and build up simple objects
//////////////////////////////////////////////////////////////////////////////////
Pcap.prototype.icmp = function (buffer, obj, pos) {
obj.icmp = {
_pos: pos,
length: buffer.length,
type: buffer[0],
code: buffer[1],
sum: buffer.readUInt16BE(2),
id: buffer.readUInt16BE(4),
sequence: buffer.readUInt16BE(6)
};
obj.icmp.data = buffer.slice(8);
};
Pcap.prototype.tcp = function (buffer, obj, pos) {
obj.tcp = {
_pos: pos,
length: buffer.length,
sport: buffer.readUInt16BE(0),
dport: buffer.readUInt16BE(2),
seq: buffer.readUInt32BE(4),
ack: buffer.readUInt32BE(8),
off: ((buffer[12] >> 4) & 0xf),
res1: (buffer[12] & 0xf),
flags: buffer[13],
res2: (buffer[13] >> 6 & 0x3),
urgflag: (buffer[13] >> 5 & 0x1),
ackflag: (buffer[13] >> 4 & 0x1),
pshflag: (buffer[13] >> 3 & 0x1),
rstflag: (buffer[13] >> 2 & 0x1),
synflag: (buffer[13] >> 1 & 0x1),
finflag: (buffer[13] >> 0 & 0x1),
win: buffer.readUInt16BE(14),
sum: buffer.readUInt16BE(16),
urp: buffer.readUInt16BE(18)
};
if (4*obj.tcp.off > buffer.length) {
obj.tcp.data = new Buffer(0);
} else {
obj.tcp.data = buffer.slice(4*obj.tcp.off);
}
};
Pcap.prototype.udp = function (buffer, obj, pos) {
obj.udp = {
_pos: pos,
length: buffer.length,
sport: buffer.readUInt16BE(0),
dport: buffer.readUInt16BE(2),
ulen: buffer.readUInt16BE(4),
sum: buffer.readUInt16BE(6)
};
obj.udp.data = buffer.slice(8);
};
Pcap.prototype.gre = function (buffer, obj, pos) {
obj.gre = {
flags_version: buffer.readUInt16BE(0),
type: buffer.readUInt16BE(2)
};
var bpos = 4;
var offset = 0;
if (obj.gre.flags_version & (0x8000 | 0x4000)) {
bpos += 2;
offset = buffer.readUInt16BE(bpos);
bpos += 2;
}
// key
if (obj.gre.flags_version & 0x2000) {
bpos += 4;
}
// sequence number
if (obj.gre.flags_version & 0x1000) {
bpos += 4;
}
// routing
if (obj.gre.flags_version & 0x4000) {
bpos += 3;
while (1) {
var len = buffer.readUInt16BE(bpos);
if (len === 0)
break;
bpos += len;
}
}
this.ip4(buffer.slice(bpos), obj, pos+bpos);
};
Pcap.prototype.ip4 = function (buffer, obj, pos) {
obj.ip = {
length: buffer.length,
hl: (buffer[0] & 0xf),
v: ((buffer[0] >> 4) & 0xf),
tos: buffer[1],
len: buffer.readUInt16BE(2),
id: buffer.readUInt16BE(4),
off: buffer.readUInt16BE(6),
ttl: buffer[8],
p: buffer[9],
sum: buffer.readUInt16BE(10),
addr1: exports.inet_ntoa(buffer.readUInt32BE(12)),
addr2: exports.inet_ntoa(buffer.readUInt32BE(16))
};
switch(obj.ip.p) {
case 1:
this.icmp(buffer.slice(obj.ip.hl*4, obj.ip.len), obj, pos + obj.ip.hl*4);
break;
case 6:
this.tcp(buffer.slice(obj.ip.hl*4, obj.ip.len), obj, pos + obj.ip.hl*4);
break;
case 17:
this.udp(buffer.slice(obj.ip.hl*4, obj.ip.len), obj, pos + obj.ip.hl*4);
break;
case 47:
this.gre(buffer.slice(obj.ip.hl*4, obj.ip.len), obj, pos + obj.ip.hl*4);
break;
default:
console.log("Unknown ip.p", obj);
}
};
Pcap.prototype.ip6 = function (buffer, obj, pos) {
obj.ip = {
length: buffer.length,
v: ((buffer[0] >> 4) & 0xf),
tc: ((buffer[0] & 0xf) << 4) | ((buffer[1] >> 4) & 0xf),
flow: ((buffer[1] & 0xf) << 16) | (buffer[2] << 8) | buffer[3],
len: buffer.readUInt16BE(4),
p: buffer[6],
hopLimt: buffer[7],
addr1: buffer.slice(8,24).toString("hex"),
addr2: buffer.slice(24,40).toString("hex")
};
var offset = 40;
while (offset < buffer.length) {
switch(obj.ip.p) {
case 0: //IPPROTO_HOPOPTS:
case 60: //IPPROTO_DSTOPTS:
case 43: //IPPROTO_ROUTING:
obj.ip.p = buffer[offset];
offset += ((buffer[offset+1] + 1) << 3);
break;
case 1:
case 58:
this.icmp(buffer.slice(offset, offset+obj.ip.len), obj, pos + offset);
return;
case 6:
this.tcp(buffer.slice(offset, offset+obj.ip.len), obj, pos + offset);
return;
case 17:
this.udp(buffer.slice(offset, offset+obj.ip.len), obj, pos + offset);
return;
default:
console.log("Unknown ip.p", obj);
return;
}
}
};
Pcap.prototype.ethertype = function(buffer, obj, pos) {
obj.ether.type = buffer.readUInt16BE(0);
switch(obj.ether.type) {
case 0x0800:
this.ip4(buffer.slice(2), obj, pos+2);
break;
case 0x86dd:
this.ip6(buffer.slice(2), obj, pos+2);
break;
case 0x8100: // VLAN
this.ethertype(buffer.slice(4), obj, pos+4);
break;
default:
console.trace("Unknown ether.type", obj);
break;
}
};
Pcap.prototype.ether = function (buffer, obj, pos) {
obj.ether = {
length: buffer.length,
addr1: buffer.slice(0, 6).toString('hex', 0, 6),
addr2: buffer.slice(6, 12).toString('hex', 0, 6)
};
this.ethertype(buffer.slice(12), obj, pos+12);
};
Pcap.prototype.pcap = function (buffer, obj) {
if (this.bigEndian) {
obj.pcap = {
ts_sec: buffer.readUInt32BE(0),
ts_usec: buffer.readUInt32BE(4),
incl_len: buffer.readUInt32BE(8),
orig_len: buffer.readUInt32BE(12)
};
} else {
obj.pcap = {
ts_sec: buffer.readUInt32LE(0),
ts_usec: buffer.readUInt32LE(4),
incl_len: buffer.readUInt32LE(8),
orig_len: buffer.readUInt32LE(12)
};
}
switch(this.linkType) {
case 0: // NULL
this.ip4(buffer.slice(20, obj.pcap.incl_len + 16), obj, 20);
break;
case 1: // Ether
this.ether(buffer.slice(16, obj.pcap.incl_len + 16), obj, 16);
break;
case 12: // Raw
this.ip4(buffer.slice(16, obj.pcap.incl_len + 16), obj, 16);
break;
case 113: // SLL
this.ip4(buffer.slice(32, obj.pcap.incl_len + 16), obj, 32);
break;
default:
console.log("Unsupported pcap file", this.filename, "link type", this.linkType);
break;
}
};
Pcap.prototype.decode = function (buffer, obj) {
this.readHeader();
this.pcap(buffer, obj);
};
Pcap.prototype.getHeaderNg = function () {
var buffer = this.readHeader();
var b = new Buffer(32 + 24);
b.writeUInt32LE(0x0A0D0D0A, 0); // Block Type
b.writeUInt32LE(32, 4); // Block Len 1
b.writeUInt32LE(0x1A2B3C4D, 8); // Byte Order Magic
b.writeUInt16LE(1, 12); // Major
b.writeUInt16LE(0, 14); // Minor
b.writeUInt32LE(0xffffffff, 16); // Unknown Section Length 1
b.writeUInt32LE(0xffffffff, 20); // Unknown Section Length 2
b.writeUInt32LE(0, 24); // Options
b.writeUInt32LE(32, 28); // Block Len 2
b.writeUInt32LE(0x00000001, 32); // Block Type
b.writeUInt32LE(24, 36); // Block Len 1
b.writeUInt16LE(buffer.readUInt32LE(20), 40); // Link Type
b.writeUInt16LE(0, 42); // Reserved
b.writeUInt32LE(buffer.readUInt32LE(16), 44); // SnapLen
b.writeUInt32LE(0, 48); // Options
b.writeUInt32LE(24, 52); // Block Len 2
return b;
};
//////////////////////////////////////////////////////////////////////////////////
//// Reassembly array of packets
//////////////////////////////////////////////////////////////////////////////////
exports.reassemble_icmp = function (packets, cb) {
var results = [];
packets.forEach(function (item) {
var key = item.ip.addr1;
if (results.length === 0 || key !== results[results.length-1].key) {
var result = {
key: key,
data: item.icmp.data,
ts: item.pcap.ts_sec*1000 + Math.round(item.pcap.ts_usec/1000)
};
results.push(result);
} else {
var newBuf = new Buffer(results[results.length-1].data.length + item.icmp.data.length);
results[results.length-1].data.copy(newBuf);
item.icmp.data.copy(newBuf, results[results.length-1].data.length);
results[results.length-1].data = newBuf;
}
});
cb(null, results);
};
exports.reassemble_udp = function (packets, cb) {
try {
var results = [];
packets.forEach(function (item) {
var key = item.ip.addr1 + ':' + item.udp.sport;
if (results.length === 0 || key !== results[results.length-1].key) {
var result = {
key: key,
data: item.udp.data,
ts: item.pcap.ts_sec*1000 + Math.round(item.pcap.ts_usec/1000)
};
results.push(result);
} else {
var newBuf = new Buffer(results[results.length-1].data.length + item.udp.data.length);
results[results.length-1].data.copy(newBuf);
item.udp.data.copy(newBuf, results[results.length-1].data.length);
results[results.length-1].data = newBuf;
}
});
cb(null, results);
} catch (e) {
cb(e, results);
}
};
// Needs to be rewritten since its possible for packets to be
// dropped by windowing and other things to actually be displayed allowed.
// If multiple tcp sessions in one moloch session display can be wacky/wrong.
exports.reassemble_tcp = function (packets, skey, cb) {
try {
// Remove syn, rst, 0 length packets and figure out min/max seq number
var packets2 = [];
var info = {};
var keys = [];
var key, i, ilen;
for (i = 0, ilen = packets.length; i < ilen; i++) {
if (packets[i].tcp.data.length === 0 || packets[i].tcp.rstflag || packets[i].tcp.synflag) {
continue;
}
key = packets[i].ip.addr1 + ':' + packets[i].tcp.sport;
if (!info[key]) {
info[key] = {min: packets[i].tcp.seq, max: packets[i].tcp.seq, wrapseq: false, wrapack: false};
keys.push(key);
}
else if (info[key].min > packets[i].tcp.seq) {
info[key].min = packets[i].tcp.seq;
} else if (info[key].max < packets[i].tcp.seq) {
info[key].max = packets[i].tcp.seq;
}
packets2.push(packets[i]);
}
packets = packets2;
packets2 = [];
if (packets.length === 0) {
return cb(null, packets);
}
// Do we need to wrap the packets
var needwrap = false;
if (info[keys[0]] && info[keys[0]].max - info[keys[0]].min > 0x7fffffff) {
info[keys[0]].wrapseq = true;
info[keys[1]].wrapack = true;
needwrap = true;
}
if (info[keys[1]] && info[keys[1]].max - info[keys[1]].min > 0x7fffffff) {
info[keys[1]].wrapseq = true;
info[keys[0]].wrapack = true;
needwrap = true;
}
// Wrap the packets
if (needwrap) {
for (i = 0, ilen = packets.length; i < ilen; i++) {
key = packets[i].ip.addr1 + ':' + packets[i].tcp.sport;
if (info[key].wrapseq && packets[i].tcp.seq < 0x7fffffff) {
packets[i].tcp.seq += 0xffffffff;
}
if (info[key].wrapack && packets[i].tcp.ack < 0x7fffffff) {
packets[i].tcp.ack += 0xffffffff;
}
}
}
// Sort Packets
var clientKey = packets[0].ip.addr1 + ':' + packets[0].tcp.sport;
packets.sort(function(a,b) {
if ((a.ip.addr1 === b.ip.addr1) && (a.tcp.sport === b.tcp.sport)) {
return (a.tcp.seq - b.tcp.seq);
}
if (clientKey === a.ip.addr1 + ':' + a.tcp.sport) {
return ((a.tcp.seq + a.tcp.data.length-1) - b.tcp.ack);
}
return (a.tcp.ack - (b.tcp.seq + b.tcp.data.length-1) );
});
// Now divide up conversation
var clientSeq = 0;
var hostSeq = 0;
var start = 0;
var previous = 0;
var results = [];
packets.forEach(function (item) {
var key = item.ip.addr1 + ':' + item.tcp.sport;
if (key === clientKey) {
if (clientSeq >= (item.tcp.seq + item.tcp.data.length)) {
return;
}
clientSeq = (item.tcp.seq + item.tcp.data.length);
} else {
if (hostSeq >= (item.tcp.seq + item.tcp.data.length)) {
return;
}
hostSeq = (item.tcp.seq + item.tcp.data.length);
}
var result;
if (results.length === 0 || key !== results[results.length-1].key) {
previous = start = item.tcp.seq;
result = {
key: key,
data: item.tcp.data,
ts: item.pcap.ts_sec*1000 + Math.round(item.pcap.ts_usec/1000)
};
results.push(result);
} else if (item.tcp.seq - previous > 0xffff) {
results.push({key: "", data: new Buffer(0), ts: item.pcap.ts_sec*1000 + Math.round(item.pcap.ts_usec/1000)});
// Larger then max window size packets missing
previous = start = item.tcp.seq;
result = {
key: key,
data: item.tcp.data,
ts: item.pcap.ts_sec*1000 + Math.round(item.pcap.ts_usec/1000)
};
results.push(result);
} else {
previous = item.tcp.seq;
var newBuf = new Buffer(item.tcp.data.length + item.tcp.seq - start);
results[results.length-1].data.copy(newBuf);
item.tcp.data.copy(newBuf, item.tcp.seq - start);
results[results.length-1].data = newBuf;
}
});
if (skey !== results[0].key) {
results.unshift({data: new Buffer(0), key: skey});
}
cb(null, results);
} catch (e) {
cb(e, null);
}
};