Files
x/dialer/tcp/dialer.go
T
Andrew Beresford cf70a0cbe1 Add configurable TCP keepalives to TCP listener and dialer
Exposes TCP keepalive configuration via listener and dialer metadata:

  keepalive: true
  keepalive.idle: 30s
  keepalive.interval: 10s
  keepalive.count: 6

When enabled, the OS sends keepalive probes after the idle period and
tears down the socket if the remote does not respond. This causes any
blocked Read() on a dead connection to return promptly, releasing
goroutines and memory — covering both legs of a CONNECT tunnel (the
inbound client connection via the listener, and the outbound upstream
connection via the dialer).

This is the correct alternative to a hard application-level read
deadline (SetReadDeadline) for detecting dead connections, as it
distinguishes truly dead connections from legitimately idle ones.

Relates to: https://github.com/go-gost/x/issues/91
2026-05-08 11:33:54 +01:00

72 lines
1.4 KiB
Go

package tcp
import (
"context"
"net"
"github.com/go-gost/core/dialer"
"github.com/go-gost/core/logger"
md "github.com/go-gost/core/metadata"
xctx "github.com/go-gost/x/ctx"
"github.com/go-gost/x/internal/net/proxyproto"
"github.com/go-gost/x/registry"
)
func init() {
registry.DialerRegistry().Register("tcp", NewDialer)
}
type tcpDialer struct {
md metadata
logger logger.Logger
options dialer.Options
}
func NewDialer(opts ...dialer.Option) dialer.Dialer {
options := dialer.Options{}
for _, opt := range opts {
opt(&options)
}
return &tcpDialer{
logger: options.Logger,
options: options,
}
}
func (d *tcpDialer) Init(md md.Metadata) (err error) {
return d.parseMetadata(md)
}
func (d *tcpDialer) Dial(ctx context.Context, addr string, opts ...dialer.DialOption) (net.Conn, error) {
var options dialer.DialOptions
for _, opt := range opts {
opt(&options)
}
conn, err := options.Dialer.Dial(ctx, "tcp", addr)
if err != nil {
d.logger.Error(err)
return conn, err
}
if d.md.keepalive {
if tc, ok := conn.(*net.TCPConn); ok {
tc.SetKeepAliveConfig(net.KeepAliveConfig{
Enable: true,
Idle: d.md.keepaliveIdle,
Interval: d.md.keepaliveInterval,
Count: d.md.keepaliveCount,
})
}
}
conn = proxyproto.WrapClientConn(
d.options.ProxyProtocol,
xctx.SrcAddrFromContext(ctx),
xctx.DstAddrFromContext(ctx),
conn)
return conn, err
}