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go-tcp-transport

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A libp2p transport implementation for tcp, including reuseport socket options.

go-tcp-transport is an implementation of the libp2p transport interface that streams data over TCP/IP sockets. It is included by default in the main go-libp2p "entry point" module.

Table of Contents

Install

go-tcp-transport is included as a dependency of go-libp2p, which is the most common libp2p entry point. If you depend on go-libp2p, there is generally no need to explicitly depend on this module.

go-tcp-transport is a standard Go module which can be installed with:

go get github.com/libp2p/go-tcp-transport

This repo is gomod-compatible, and users of go 1.11 and later with modules enabled will automatically pull the latest tagged release by referencing this package. Upgrades to future releases can be managed using go get, or by editing your go.mod file as described by the gomod documentation.

Usage

TCP is one of the default transports enabled when constructing a standard libp2p Host, along with WebSockets.

Calling libp2p.New to construct a libp2p Host will enable the TCP transport, unless you override the default transports by passing in Options to libp2p.New.

To explicitly enable the TCP transport while constructing a host, use the libp2p.Transport option, passing in the NewTCPTransport constructor function:

import (
    "context"

    libp2p "github.com/libp2p/go-libp2p"
    tcp "github.com/libp2p/go-tcp-transport"
)

ctx := context.Background()

// TCP only:
h, err := libp2p.New(ctx,
    libp2p.Transport(tcp.NewTCPTransport)
)

The example above will replace the default transports with a single TCP transport. To add multiple tranports, use ChainOptions:

// TCP and QUIC:
h, err := libp2p.New(ctx,
    libp2p.ChainOptions(
        libp2p.Transport(tcp.NewTCPTransport),
        libp2p.Transport(quic.NewTransport)) // see https://github.com/libp2p/go-libp2p-quic-transport
)

Addresses

The TCP transport supports multiaddrs that contain a tcp component, provided that there is sufficient addressing information for the IP layer of the connection.

Examples:

addr description
/ip4/1.2.3.4/tcp/1234 IPv4: 1.2.3.4, TCP port 1234
/ip6/::1/tcp/1234 IPv6 loopback, TCP port 1234
/dns4/example.com/tcp/80 DNS over IPv4, hostname example.com, TCP port 80

Support for IP layer protocols is provided by the go-multiaddr-net module.

Security and Multiplexing

Because TCP lacks native connection security and stream multiplexing facilities, the TCP transport uses a transport upgrader to provide those features. The transport upgrader negotiates transport security and multiplexing for each connection according to the protocols supported by each party.

reuseport

The SO_REUSEPORT socket option allows multiple processes or threads to bind to the same TCP port, provided that all of them set the socket option. This has some performance benefits, and it can potentially assist in NAT traversal by only requiring one port to be accessible for many connections.

The reuseport functionality is provided by a seperate module, go-reuseport-transport. It is enabled by default, but can be disabled at runtime by setting the LIBP2P_TCP_REUSEPORT environment variable to false or 0.

Contribute

PRs are welcome!

Small note: If editing the Readme, please conform to the standard-readme specification.

License

MIT © Jeromy Johnson


The last gx published version of this module was: 2.0.28: QmTGiDkw4eeKq31wwpQRk5GwWiReaxrcTQLuCCLWgfKo5M

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