ginuerzh
8fd5200bf1
Commit 0522ae8 added inline DNS resolution (PreferGo: true) in Resolve(),
resolving domain names to IPs before routing. This caused the SOCKS5
connector to send CONNECT with ATYP=IPv4 instead of ATYP=domain, breaking
chains where the backend (e.g., ssh -D) cannot reach the gost-resolved IP.
Revert the DNS fallback in Resolve() — return the address unchanged so
the original hostname flows through the proxy chain. Instead, add
net.Resolver{PreferGo: true} to the TCP dialer in internal/net/dialer,
which resolves DNS at the point of actual TCP connection — still pure
Go (no cgo thread exhaustion) but after the proxy chain routing is done.
Also rename resovle.go → resolve.go (fix typo).
Fixes go-gost/gost#877
64 lines
1.8 KiB
Go
64 lines
1.8 KiB
Go
package net
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import (
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"context"
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"fmt"
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"net"
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"github.com/go-gost/core/hosts"
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"github.com/go-gost/core/logger"
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"github.com/go-gost/core/resolver"
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ctxvalue "github.com/go-gost/x/ctx"
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)
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// Resolve resolves addr to a concrete IP address. If hosts is non-nil, it is
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// consulted first. If r is non-nil and no host mapping matched, the resolver
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// is used. If neither is available, the address is returned unchanged so that
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// the original hostname is preserved for downstream connectors (e.g., SOCKS5
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// ATYP=domain). DNS resolution is deferred to the final TCP dialer, which uses
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// a pure-Go resolver to avoid cgo thread exhaustion.
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func Resolve(ctx context.Context, network, addr string, r resolver.Resolver, hosts hosts.HostMapper, log logger.Logger) (string, error) {
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if addr == "" {
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return addr, nil
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}
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host, port, _ := net.SplitHostPort(addr)
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if host == "" {
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return addr, nil
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}
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if log == nil {
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log = logger.Default()
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}
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log = log.WithFields(map[string]any{
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"sid": ctxvalue.SidFromContext(ctx),
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})
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if hosts != nil {
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if ips, _ := hosts.Lookup(ctx, network, host); len(ips) > 0 {
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log.Debugf("hit host mapper: %s -> %s", host, ips)
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return net.JoinHostPort(ips[0].String(), port), nil
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}
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}
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if r != nil {
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ips, err := r.Resolve(ctx, network, host)
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if err != nil {
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if err == resolver.ErrInvalid {
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return addr, nil
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}
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log.Error(err)
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}
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if len(ips) == 0 {
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return "", fmt.Errorf("resolver: domain %s does not exist", host)
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}
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return net.JoinHostPort(ips[0].String(), port), nil
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}
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// Return the address unchanged so that the original hostname is
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// preserved through the proxy chain. DNS resolution happens in the
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// final TCP dialer (dialer.go) which uses net.Resolver{PreferGo: true}
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// to avoid cgo-based lookups that block OS threads.
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return addr, nil
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}
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