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iefsergeiefserge
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Merge pull request #79 from runtimejs/ip4-fragmentation
IP4 fragmented packets reassembly
2 parents 5e46275 + 8048564 commit 2548693

16 files changed

+1062
-8
lines changed

‎js/core/net/interface.js

+1
Original file line numberDiff line numberDiff line change
@@ -35,6 +35,7 @@ function Interface(macAddr) {
3535
this.bufferDataOffset = 0;
3636
this.arp = new ARPResolver(this);
3737
this.isNetworkEnabled = false;
38+
this.fragments = new Map();
3839
}
3940

4041
Interface.prototype.disableArp = function() {

‎js/core/net/interfaces.js

+4
Original file line numberDiff line numberDiff line change
@@ -33,3 +33,7 @@ exports.getByName = function(intfName) {
3333

3434
return null;
3535
};
36+
37+
exports.forEach = function(fn) {
38+
intfs.forEach(fn);
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};

‎js/core/net/ip4-fragments.js

+190
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,190 @@
1+
// Copyright 2015 runtime.js project authors
2+
//
3+
// Licensed under the Apache License, Version 2.0 (the "License");
4+
// you may not use this file except in compliance with the License.
5+
// You may obtain a copy of the License at
6+
//
7+
// http://www.apache.org/licenses/LICENSE-2.0
8+
//
9+
// Unless required by applicable law or agreed to in writing, software
10+
// distributed under the License is distributed on an "AS IS" BASIS,
11+
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12+
// See the License for the specific language governing permissions and
13+
// limitations under the License.
14+
15+
'use strict';
16+
17+
var ip4header = require('./ip4-header');
18+
var ip4receive = require('./ip4-receive');
19+
var timeNow = require('../../utils').timeNow;
20+
var FRAGMENT_QUEUE_MAX_AGE_MS = 30000;
21+
var FRAGMENT_QUEUE_MAX_COUNT = 100;
22+
23+
function fragmentHash(srcIP, destIP, protocolId, packetId) {
24+
return srcIP.toInteger() + '-' + destIP.toInteger() + '-' + (packetId + (protocolId << 16));
25+
}
26+
27+
function dropFragmentQueue(intf, hash) {
28+
intf.fragments.delete(hash);
29+
}
30+
31+
exports.addFragment = function(intf, u8, headerOffset, fragmentOffset, isMoreFragments) {
32+
var headerLength = ip4header.getHeaderLength(u8, headerOffset);
33+
var protocolId = ip4header.getProtocolId(u8, headerOffset);
34+
var srcIP = ip4header.getSrcIP(u8, headerOffset);
35+
var destIP = ip4header.getDestIP(u8, headerOffset);
36+
var packetId = ip4header.getIdentification(u8, headerOffset);
37+
var nextOffset = headerOffset + headerLength;
38+
39+
var hash = fragmentHash(srcIP, destIP, packetId, protocolId);
40+
41+
var firstFragment = false;
42+
var fragmentQueue = intf.fragments.get(hash);
43+
if (!fragmentQueue) {
44+
if (intf.fragments.size >= FRAGMENT_QUEUE_MAX_COUNT) {
45+
// too many fragment queues
46+
return;
47+
}
48+
49+
firstFragment = true;
50+
fragmentQueue = {
51+
receivedLength: 0,
52+
totalLength: 0,
53+
createdAt: timeNow(),
54+
fragments: []
55+
};
56+
}
57+
58+
var fragmentLength = u8.length - nextOffset;
59+
if (fragmentLength <= 0) {
60+
return;
61+
}
62+
63+
var fragmentEnd = fragmentOffset + fragmentLength;
64+
65+
if (fragmentEnd > 0xffff) {
66+
return;
67+
}
68+
69+
// Locate non overlapping portion of new fragment
70+
var newOffset = fragmentOffset;
71+
var newEnd = fragmentEnd;
72+
var newNextOffset = nextOffset;
73+
for (var i = 0, l = fragmentQueue.fragments.length; i < l; ++i) {
74+
var fragment = fragmentQueue.fragments[i];
75+
if (!fragment) {
76+
continue;
77+
}
78+
79+
var fragBegin = fragment[0];
80+
var fragEnd = fragBegin + fragment[1];
81+
82+
var overlapOffset = newOffset >= fragBegin && newOffset <= fragEnd;
83+
var overlapEnd = newEnd >= fragBegin && newEnd <= fragEnd;
84+
85+
// New fragment is fully contained within another fragment,
86+
// just ignore it
87+
if (overlapOffset && overlapEnd) {
88+
return;
89+
}
90+
91+
// First fragment byte is somewhere withing existing fragment
92+
if (overlapOffset && newOffset < fragEnd) {
93+
newNextOffset += fragEnd - newOffset;
94+
newOffset = fragEnd;
95+
}
96+
97+
// Last fragment byte is somewhere withing existing fragment
98+
if (overlapEnd && newEnd > fragBegin) {
99+
newEnd = fragBegin;
100+
}
101+
}
102+
103+
// Remove old fragments fully contained within the new one
104+
// By doing this we can avoid splitting big new fragments into
105+
// smaller chunks
106+
var removedIndex = -1;
107+
for (var i = 0, l = fragmentQueue.fragments.length; i < l; ++i) {
108+
var fragment = fragmentQueue.fragments[i];
109+
if (!fragment) {
110+
continue;
111+
}
112+
113+
var fragBegin = fragment[0];
114+
var fragEnd = fragBegin + fragment[1];
115+
116+
if (fragBegin >= newOffset && fragBegin <= newEnd &&
117+
fragEnd >= newOffset && fragEnd <= newEnd) {
118+
// remove this old fragment
119+
fragmentQueue.fragments[i] = null;
120+
fragmentQueue.receivedLength -= fragment[1];
121+
removedIndex = i;
122+
}
123+
}
124+
125+
var newLength = newEnd - newOffset;
126+
127+
// fragment offset - fragement length - buffer data offset - buffer
128+
var newFragment = [newOffset, newLength, newNextOffset, u8];
129+
130+
if (removedIndex >= 0) {
131+
fragmentQueue.fragments[removedIndex] = newFragment;
132+
} else {
133+
fragmentQueue.fragments.push(newFragment);
134+
}
135+
136+
fragmentQueue.receivedLength += newLength;
137+
138+
// Last fragment?
139+
if (!isMoreFragments) {
140+
141+
// Another last fragment?
142+
if (fragmentQueue.totalLength > fragmentEnd) {
143+
// Wrong len
144+
return;
145+
}
146+
147+
fragmentQueue.totalLength = fragmentEnd;
148+
}
149+
150+
if (firstFragment) {
151+
intf.fragments.set(hash, fragmentQueue);
152+
}
153+
154+
if (fragmentQueue.totalLength === fragmentQueue.receivedLength) {
155+
var u8asm = new Uint8Array(fragmentQueue.totalLength);
156+
for (var i = 0, l = fragmentQueue.fragments.length; i < l; ++i) {
157+
var fragment = fragmentQueue.fragments[i];
158+
if (!fragment) {
159+
continue;
160+
}
161+
162+
var itemOffset = fragment[0];
163+
var itemLength = fragment[1];
164+
var itemNextOffset = fragment[2];
165+
var itemBuffer = fragment[3];
166+
u8asm.set(itemBuffer.subarray(itemNextOffset, itemNextOffset + itemLength), itemOffset);
167+
}
168+
169+
dropFragmentQueue(intf, hash);
170+
ip4receive(intf, srcIP, destIP, protocolId, u8asm, 0);
171+
return;
172+
}
173+
};
174+
175+
/**
176+
* Timer tick
177+
*
178+
* @param {Interface} intf Network interface
179+
*/
180+
exports.tick = function(intf) {
181+
var time = timeNow();
182+
183+
for (var pair of intf.fragments) {
184+
var hash = pair[0];
185+
var fragmentQueue = pair[1];
186+
if (fragmentQueue.createdAt + FRAGMENT_QUEUE_MAX_AGE_MS <= time) {
187+
dropFragmentQueue(intf, hash);
188+
}
189+
}
190+
};

‎js/core/net/ip4-header.js

+20
Original file line numberDiff line numberDiff line change
@@ -46,6 +46,26 @@ exports.getHeaderLength = function(u8, headerOffset) {
4646
return (u8[headerOffset] & 0xf) << 2;
4747
};
4848

49+
exports.getFragmentationData = function(u8, headerOffset) {
50+
return u8view.getUint16BE(u8, headerOffset + 6);
51+
};
52+
53+
exports.getIdentification = function(u8, headerOffset) {
54+
return u8view.getUint16BE(u8, headerOffset + 4);
55+
};
56+
57+
exports.fragmentationDataIsMoreFragments = function(value) {
58+
return !!((value >>> 13) & 0x1);
59+
};
60+
61+
exports.fragmentationDataIsDontFragment = function(value) {
62+
return !!((value >>> 14) & 0x1);
63+
};
64+
65+
exports.fragmentationDataOffset = function(value) {
66+
return (value & 0x1fff) * 8;
67+
};
68+
4969
exports.minHeaderLength = minHeaderLength;
5070

5171
exports.write = function(u8, headerOffset, protocolId, srcIP, destIP, packetLength) {

‎js/core/net/ip4-receive.js

+27
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,27 @@
1+
// Copyright 2015 runtime.js project authors
2+
//
3+
// Licensed under the Apache License, Version 2.0 (the "License");
4+
// you may not use this file except in compliance with the License.
5+
// You may obtain a copy of the License at
6+
//
7+
// http://www.apache.org/licenses/LICENSE-2.0
8+
//
9+
// Unless required by applicable law or agreed to in writing, software
10+
// distributed under the License is distributed on an "AS IS" BASIS,
11+
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12+
// See the License for the specific language governing permissions and
13+
// limitations under the License.
14+
15+
'use strict';
16+
17+
var udp = require('./udp');
18+
var tcp = require('./tcp');
19+
var icmp = require('./icmp');
20+
21+
module.exports = function(intf, srcIP, destIP, protocolId, u8, nextOffset) {
22+
switch (protocolId) {
23+
case 0x01: return icmp.receive(intf, srcIP, destIP, u8, nextOffset);
24+
case 0x06: return tcp.receive(intf, srcIP, destIP, u8, nextOffset);
25+
case 0x11: return udp.receive(intf, srcIP, destIP, u8, nextOffset);
26+
}
27+
};

‎js/core/net/ip4.js

+21-8
Original file line numberDiff line numberDiff line change
@@ -15,20 +15,33 @@
1515
'use strict';
1616
var IP4Address = require('./ip4-address');
1717
var ip4header = require('./ip4-header');
18-
var udp = require('./udp');
19-
var tcp = require('./tcp');
20-
var icmp = require('./icmp');
18+
var ip4fragments = require('./ip4-fragments');
19+
var ip4receive = require('./ip4-receive');
20+
var timers = require('../timers');
21+
var interfaces = require('./interfaces');
2122

22-
exports.receive = function(intf, u8, headerOffset) {
23+
timers.scheduleTask5s(function() {
24+
interfaces.forEach(ip4fragments.tick);
25+
});
26+
27+
function handleReceive(intf, u8, headerOffset) {
2328
var headerLength = ip4header.getHeaderLength(u8, headerOffset);
2429
var protocolId = ip4header.getProtocolId(u8, headerOffset);
2530
var srcIP = ip4header.getSrcIP(u8, headerOffset);
2631
var destIP = ip4header.getDestIP(u8, headerOffset);
2732
var nextOffset = headerOffset + headerLength;
33+
ip4receive(intf, srcIP, destIP, protocolId, u8, nextOffset);
34+
}
2835

29-
switch (protocolId) {
30-
case 0x01: return icmp.receive(intf, srcIP, destIP, u8, nextOffset);
31-
case 0x06: return tcp.receive(intf, srcIP, destIP, u8, nextOffset);
32-
case 0x11: return udp.receive(intf, srcIP, destIP, u8, nextOffset);
36+
exports.receive = function(intf, u8, headerOffset) {
37+
var fragmentData = ip4header.getFragmentationData(u8, headerOffset);
38+
var isMoreFragments = ip4header.fragmentationDataIsMoreFragments(fragmentData);
39+
var fragmentOffset = ip4header.fragmentationDataOffset(fragmentData);
40+
41+
if (!isMoreFragments && fragmentOffset === 0) {
42+
handleReceive(intf, u8, headerOffset);
43+
return;
3344
}
45+
46+
ip4fragments.addFragment(intf, u8, headerOffset, fragmentOffset, isMoreFragments);
3447
};

‎js/core/net/mac-address.js

+27
Original file line numberDiff line numberDiff line change
@@ -42,4 +42,31 @@ MACAddress.prototype.equals = function(that) {
4242
MACAddress.BROADCAST = new MACAddress(0xff, 0xff, 0xff, 0xff, 0xff, 0xff);
4343
MACAddress.ZERO = new MACAddress(0, 0, 0, 0, 0, 0);
4444

45+
MACAddress.parse = function(str) {
46+
if (str instanceof MACAddress) {
47+
return str;
48+
}
49+
50+
if ('string' !== typeof str) {
51+
return null;
52+
}
53+
54+
var p = str.trim().split(':');
55+
if (6 !== p.length) {
56+
return null;
57+
}
58+
59+
var a = new Array(6);
60+
for (var i = 0; i < 6; ++i) {
61+
var v = parseInt(p[i], 16) | 0;
62+
if (v !== parseInt(p[i], 16) || v < 0 || v > 255) {
63+
return null;
64+
}
65+
66+
a[i] = v;
67+
}
68+
69+
return new MACAddress(a[0], a[1], a[2], a[3], a[4], a[5]);
70+
};
71+
4572
module.exports = MACAddress;

‎js/core/timers.js

+36
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,36 @@
1+
// Copyright 2015 runtime.js project authors
2+
//
3+
// Licensed under the Apache License, Version 2.0 (the "License");
4+
// you may not use this file except in compliance with the License.
5+
// You may obtain a copy of the License at
6+
//
7+
// http://www.apache.org/licenses/LICENSE-2.0
8+
//
9+
// Unless required by applicable law or agreed to in writing, software
10+
// distributed under the License is distributed on an "AS IS" BASIS,
11+
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12+
// See the License for the specific language governing permissions and
13+
// limitations under the License.
14+
15+
'use strict';
16+
17+
var tasks5s = [];
18+
19+
setInterval(function() {
20+
if (tasks5s.length === 0) {
21+
return;
22+
}
23+
24+
for (var i = 0, l = tasks5s.length; i < l; ++i) {
25+
tasks5s[i]();
26+
}
27+
}, 5000);
28+
29+
/**
30+
* Schedule task to run every 5 seconds
31+
*
32+
* @param {function} fn Function to run
33+
*/
34+
exports.scheduleTask5s = function(fn) {
35+
tasks5s.push(fn);
36+
};

‎js/test/unit/index.js

+1
Original file line numberDiff line numberDiff line change
@@ -28,6 +28,7 @@ stream.on('data', function(v) {
2828
stream.on('end', shutdown);
2929

3030
require('./script');
31+
require('./lib/test');
3132
require('./buffers');
3233
require('./platform');
3334
require('./timers');

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