fastdialer

README

Fastdialer

Fastdialer is implementation of net.Dialer with lot of features like DNS Cache , Dial History etc

Features

• DNS Cache
• Dial History
• Supports Memory/Hybrid/Disk Cache.
• Supports Old/New TLS and x509 versions
• Supports Resolution Using Hosts File
• Cross Platform and more..

For more details and documentation refer GoDoc.

ZTLS Fallback

When the TLS handshake of DialTLS or DialTLSWithConfig fails, fastdialer retries it once with zcrypto (ztls), to reach servers that crypto/tls rejects, such as servers with old TLS versions or legacy ciphers. The retry uses ztls.ChromeCiphers and the default ztls curves instead of the cipher suites and curve preferences of the config. It retries only when:

• the dial context isn't done, the handshake didn't time out, and the server's reply, if any, was TLS.
• the TLS config allows versions older than TLS 1.3.
• the TLS config uses nothing that zcrypto can't carry over: InsecureSkipVerify is true, and the config sets no VerifyPeerCertificate or VerifyConnection callback, no GetClientCertificate, and no Encrypted Client Hello settings. A Certificates chain is copied onto the retry. Otherwise the retry would verify the server differently, omit a certificate chosen by callback, or send the hidden server name in the clear.

Plain dials, including dials through a proxy, impersonated dials and ztls dials never fall back. A dial that falls back returns a *ztls.Conn instead of a *tls.Conn, which WithTLSData doesn't record. If the retry fails too, the error includes both failures.

To disable the fallback, set DisableZtlsFallback in the options or DISABLE_ZTLS_FALLBACK=true in the environment. Either one is enough.

Pinning a Host to an IP

WithResolveOverride makes dials to one host connect to the given IP instead of resolving it, like curl --resolve. The hostname is still sent as SNI, and other hosts dialed with the same context, such as redirect targets or a proxy, are resolved as usual.

ctx := fastdialer.WithResolveOverride(context.Background(), "example.com", "192.0.2.10")
conn, err := dialer.DialTLS(ctx, "tcp", "example.com:443")

Example

An Example showing usage of fastdialer as a library is specified here

cd example/
go run main.go

License

fastdialer is distributed under MIT License