Mirror: Best-effort discovery of the machine's local network using just Node.js dgram sockets
fix: check subnet for dhcp discovery (#12)
* fix: check subnet for dhcp discovery
* Add changeset
---------
Co-authored-by: Phil Pluckthun <phil@kitten.sh>
authored by
Stephen Zhou
Phil Pluckthun
and committed by
GitHub
f5b38f9c
463aba4c
+37
-1
+5
.changeset/shaggy-walls-argue.md
+5
.changeset/shaggy-walls-argue.md
+14
src/__tests__/network.test.ts
+14
src/__tests__/network.test.ts
···
6
6
toIpStr,
7
7
interfaceAssignments,
8
8
matchAssignment,
9
+
isSameSubnet,
9
10
} from '../network';
10
11
11
12
describe(parseMacStr, () => {
···
30
31
expect(toIpStr(parseIpStr(addr))).toBe(addr);
31
32
}
32
33
);
34
+
});
35
+
36
+
describe(isSameSubnet, () => {
37
+
it('returns true for same subnet', () => {
38
+
expect(isSameSubnet('192.168.1.1', '192.168.1.2', '255.255.255.0')).toBe(
39
+
true
40
+
);
41
+
});
42
+
it('returns false for different subnet', () => {
43
+
expect(isSameSubnet('192.168.1.1', '192.168.2.1', '255.255.255.0')).toBe(
44
+
false
45
+
);
46
+
});
33
47
});
34
48
35
49
describe(interfaceAssignments, () => {
+7
-1
src/dhcp.ts
+7
-1
src/dhcp.ts
···
1
1
import { randomBytes } from 'node:crypto';
2
2
import { createSocket } from 'node:dgram';
3
-
import { parseIpStr, toIpStr, parseMacStr } from './network';
3
+
import { parseIpStr, toIpStr, parseMacStr, isSameSubnet } from './network';
4
4
import type { NetworkAssignment } from './types';
5
5
6
6
class DHCPTimeoutError extends TypeError {
···
57
57
const socket = createSocket(
58
58
{ type: 'udp4', reuseAddr: true },
59
59
(_msg, rinfo) => {
60
+
if (
61
+
!isSameSubnet(rinfo.address, assignment.address, assignment.netmask)
62
+
) {
63
+
return;
64
+
}
65
+
60
66
clearTimeout(timeout);
61
67
resolve(rinfo.address);
62
68
socket.close();
+11
src/network.ts
+11
src/network.ts
···
26
26
return addr[3] | (addr[2] << 8) | (addr[1] << 16) | (addr[0] << 24);
27
27
};
28
28
29
+
export const isSameSubnet = (
30
+
addrA: string,
31
+
addrB: string,
32
+
netmask: string
33
+
): boolean => {
34
+
const rawAddrA = parseIpStr(addrA);
35
+
const rawAddrB = parseIpStr(addrB);
36
+
const rawMask = parseIpStr(netmask);
37
+
return (rawAddrA & rawMask) === (rawAddrB & rawMask);
38
+
};
39
+
29
40
export const toIpStr = (addr: number): string => {
30
41
const MASK = (1 << 8) - 1;
31
42
let ipStr = '';