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fix: allow IPv4 and IPv6 to bind to the same port in dual-stack mode #318

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Merged
wemeetagain merged 1 commit into from
Sep 10, 2025
Merged

fix: allow IPv4 and IPv6 to bind to the same port in dual-stack mode #318

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1 change: 1 addition & 0 deletions packages/discv5/src/transport/udp.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -154,6 +154,7 @@ async function openSocket(opts: MultiaddrObject): Promise<dgram.Socket> {
recvBufferSize: 16 * MAX_PACKET_SIZE,
sendBufferSize: MAX_PACKET_SIZE,
type: opts.family === 4 ? "udp4" : "udp6",
ipv6Only: opts.family === 6,
});
await new Promise((resolve) => socket.bind(opts.port, opts.host, resolve as () => void));
return socket;
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221 changes: 170 additions & 51 deletions packages/discv5/test/unit/transport/udp.test.ts
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Expand Up @@ -101,63 +101,182 @@ describe("UDP6 transport", () => {
});

describe("UDP4+6 transport", () => {
const address4 = "127.0.0.1";
const address6 = "::1";
const nodeIdA = bytesToHex(new Uint8Array(32).fill(1));
const portA = 49523;
const multiaddr4A = multiaddr(`/ip4/${address4}/udp/${portA}`);
const multiaddr6A = multiaddr(`/ip6/${address6}/udp/${portA}`);
const a = new UDPTransportService({ bindAddrs: { ip4: multiaddr4A, ip6: multiaddr6A }, nodeId: nodeIdA });
context("with loopback addresses", () => {
const address4 = "127.0.0.1";
const address6 = "::1";
const nodeIdA = bytesToHex(new Uint8Array(32).fill(1));
const portA = 49523;
const multiaddr4A = multiaddr(`/ip4/${address4}/udp/${portA}`);
const multiaddr6A = multiaddr(`/ip6/${address6}/udp/${portA}`);
const a = new UDPTransportService({ bindAddrs: { ip4: multiaddr4A, ip6: multiaddr6A }, nodeId: nodeIdA });

const nodeIdB = bytesToHex(new Uint8Array(32).fill(2));
const portB = portA + 1;
const multiaddr4B = multiaddr(`/ip4/${address4}/udp/${portB}`);
const multiaddr6B = multiaddr(`/ip6/${address6}/udp/${portB}`);
const b = new UDPTransportService({ bindAddrs: { ip4: multiaddr4B, ip6: multiaddr6B }, nodeId: nodeIdB });
const nodeIdB = bytesToHex(new Uint8Array(32).fill(2));
const portB = portA + 1;
const multiaddr4B = multiaddr(`/ip4/${address4}/udp/${portB}`);
const multiaddr6B = multiaddr(`/ip6/${address6}/udp/${portB}`);
const b = new UDPTransportService({ bindAddrs: { ip4: multiaddr4B, ip6: multiaddr6B }, nodeId: nodeIdB });

before(async () => {
await a.start();
await b.start();
});
before(async () => {
await a.start();
await b.start();
});

after(async () => {
await a.stop();
await b.stop();
after(async () => {
await a.stop();
await b.stop();
});

it("should send and receive messages", async () => {
const messagePacket: IPacket = {
maskingIv: new Uint8Array(MASKING_IV_SIZE),
header: {
protocolId: "discv5",
version: 1,
flag: PacketType.Message,
nonce: new Uint8Array(NONCE_SIZE),
authdataSize: 32,
authdata: new Uint8Array(32).fill(2),
},
message: new Uint8Array(44).fill(1),
};
async function send(multiaddr: Multiaddr, nodeId: string, packet: IPacket): Promise<[Multiaddr, IPacket]> {
const received = new Promise<[Multiaddr, IPacket]>((resolve) =>
a.once("packet", (sender, packet) => resolve([sender, packet]))
);
await b.send(multiaddr, nodeId, packet);
return await received;
}
{
const [rSender, rPacket] = await send(multiaddr6A, nodeIdA, messagePacket);
expect(rSender.toString()).to.deep.equal(multiaddr6B.toString());
expect(rPacket.maskingIv).to.deep.equal(messagePacket.maskingIv);
expect(rPacket.header).to.deep.equal(messagePacket.header);
expect(rPacket.message).to.deep.equal(messagePacket.message);
}
{
const [rSender, rPacket] = await send(multiaddr4A, nodeIdA, messagePacket);
expect(rSender.toString()).to.deep.equal(multiaddr4B.toString());
expect(rPacket.maskingIv).to.deep.equal(messagePacket.maskingIv);
expect(rPacket.header).to.deep.equal(messagePacket.header);
expect(rPacket.message).to.deep.equal(messagePacket.message);
}
});
});

it("should send and receive messages", async () => {
const messagePacket: IPacket = {
maskingIv: new Uint8Array(MASKING_IV_SIZE),
header: {
protocolId: "discv5",
version: 1,
flag: PacketType.Message,
nonce: new Uint8Array(NONCE_SIZE),
authdataSize: 32,
authdata: new Uint8Array(32).fill(2),
},
message: new Uint8Array(44).fill(1),
};
async function send(multiaddr: Multiaddr, nodeId: string, packet: IPacket): Promise<[Multiaddr, IPacket]> {
const received = new Promise<[Multiaddr, IPacket]>((resolve) =>
context("with wildcard addresses", () => {
it("should bind to the same port on both IPv4 and IPv6", async () => {
const nodeId = bytesToHex(new Uint8Array(32).fill(3));
const port = 49525;
const multiaddr4 = multiaddr(`/ip4/0.0.0.0/udp/${port}`);
const multiaddr6 = multiaddr(`/ip6/::/udp/${port}`);

const transport = new UDPTransportService({
bindAddrs: { ip4: multiaddr4, ip6: multiaddr6 },
nodeId,
});

await transport.start();
expect(transport.bindAddrs).to.have.lengthOf(2);
expect(transport.bindAddrs[0].toString()).to.equal(multiaddr4.toString());
expect(transport.bindAddrs[1].toString()).to.equal(multiaddr6.toString());
await transport.stop();
});

it("should successfully communicate between dual-stack nodes on same port", async () => {
const nodeIdA = bytesToHex(new Uint8Array(32).fill(4));
const nodeIdB = bytesToHex(new Uint8Array(32).fill(5));
const portA = 49526;
const portB = 49527;

const multiaddr4A = multiaddr(`/ip4/127.0.0.1/udp/${portA}`);
const multiaddr6A = multiaddr(`/ip6/::1/udp/${portA}`);
const a = new UDPTransportService({
bindAddrs: { ip4: multiaddr4A, ip6: multiaddr6A },
nodeId: nodeIdA,
});

const multiaddr4B = multiaddr(`/ip4/127.0.0.1/udp/${portB}`);
const multiaddr6B = multiaddr(`/ip6/::1/udp/${portB}`);
const b = new UDPTransportService({
bindAddrs: { ip4: multiaddr4B, ip6: multiaddr6B },
nodeId: nodeIdB,
});

await a.start();
await b.start();

const messagePacket: IPacket = {
maskingIv: new Uint8Array(MASKING_IV_SIZE),
header: {
protocolId: "discv5",
version: 1,
flag: PacketType.Message,
nonce: new Uint8Array(NONCE_SIZE),
authdataSize: 32,
authdata: new Uint8Array(32).fill(2),
},
message: new Uint8Array(44).fill(1),
};

const receivedIPv4 = new Promise<[Multiaddr, IPacket]>((resolve) =>
a.once("packet", (sender, packet) => resolve([sender, packet]))
);
await b.send(multiaddr4A, nodeIdA, messagePacket);
const [senderIPv4] = await receivedIPv4;
expect(senderIPv4.toString()).to.equal(multiaddr4B.toString());

const receivedIPv6 = new Promise<[Multiaddr, IPacket]>((resolve) =>
a.once("packet", (sender, packet) => resolve([sender, packet]))
);
await b.send(multiaddr, nodeId, packet);
return await received;
}
{
const [rSender, rPacket] = await send(multiaddr6A, nodeIdA, messagePacket);
expect(rSender.toString()).to.deep.equal(multiaddr6B.toString());
expect(rPacket.maskingIv).to.deep.equal(messagePacket.maskingIv);
expect(rPacket.header).to.deep.equal(messagePacket.header);
expect(rPacket.message).to.deep.equal(messagePacket.message);
}
{
const [rSender, rPacket] = await send(multiaddr4A, nodeIdA, messagePacket);
expect(rSender.toString()).to.deep.equal(multiaddr4B.toString());
expect(rPacket.maskingIv).to.deep.equal(messagePacket.maskingIv);
expect(rPacket.header).to.deep.equal(messagePacket.header);
expect(rPacket.message).to.deep.equal(messagePacket.message);
}
await b.send(multiaddr6A, nodeIdA, messagePacket);
const [senderIPv6] = await receivedIPv6;
expect(senderIPv6.toString()).to.equal(multiaddr6B.toString());

await a.stop();
await b.stop();
});

it("should handle multiple dual-stack nodes on different ports", async () => {
const ports = [49528, 49529, 49530];
const transports: UDPTransportService[] = [];

for (let i = 0; i < ports.length; i++) {
const nodeId = bytesToHex(new Uint8Array(32).fill(10 + i));
const multiaddr4 = multiaddr(`/ip4/127.0.0.1/udp/${ports[i]}`);
const multiaddr6 = multiaddr(`/ip6/::1/udp/${ports[i]}`);
const transport = new UDPTransportService({
bindAddrs: { ip4: multiaddr4, ip6: multiaddr6 },
nodeId,
});
transports.push(transport);
}

await Promise.all(transports.map((t) => t.start()));

const messagePacket: IPacket = {
maskingIv: new Uint8Array(MASKING_IV_SIZE),
header: {
protocolId: "discv5",
version: 1,
flag: PacketType.Message,
nonce: new Uint8Array(NONCE_SIZE),
authdataSize: 32,
authdata: new Uint8Array(32).fill(2),
},
message: new Uint8Array(44).fill(1),
};

const received = new Promise<boolean>((resolve) => {
transports[1].once("packet", () => resolve(true));
});

const targetMultiaddr = multiaddr(`/ip4/127.0.0.1/udp/${ports[1]}`);
const targetNodeId = bytesToHex(new Uint8Array(32).fill(11));
await transports[0].send(targetMultiaddr, targetNodeId, messagePacket);

expect(await received).to.be.true;

await Promise.all(transports.map((t) => t.stop()));
});
});
});