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zeekayandHanzo Dev
c1f5772196
A Node bound its listener with net.Listen("tcp", ":port") and reached a
peer with net.DialTimeout("tcp", addr), so a socket path was refused at
the dialer — "missing port in address" — and could not be bound at all.
Service-to-service traffic on one host therefore had to take a TCP hop
it does not need.
NodeConfig.Address says where a node listens and overrides Port. Network
derives the network from the address — a path is a unix socket, anything
else is host:port — and the listener and both dial paths share that one
rule, so a node cannot bind one transport and be dialled on another.
A unix socket is unreachable off-host, so a node bound to one does not
advertise over mDNS. A socket file left by a process that did not unlink
it is cleared before bind; one that is still served is refused, so two
live nodes cannot steal each other's address.
Co-authored-by: Hanzo Dev <[email protected]>
57 lines
1.6 KiB
Go
57 lines
1.6 KiB
Go
// Copyright (C) 2026, Lux Industries Inc. All rights reserved.
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// See the file LICENSE for licensing terms.
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package zap
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import (
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"fmt"
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"net"
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"os"
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"strings"
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"time"
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)
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// Network returns the net package's network name for addr: a filesystem
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// path names a unix socket, anything else is a host:port TCP address.
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//
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// It is the ONE rule the listener and the dialer both use, so a node can
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// never bind one transport and be dialled on another. An address is a
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// path when it is absolute, explicitly relative, or in Linux's abstract
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// namespace ("@name") — none of which is a legal host:port.
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func Network(addr string) string {
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switch {
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case strings.HasPrefix(addr, "/"),
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strings.HasPrefix(addr, "./"),
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strings.HasPrefix(addr, "../"),
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strings.HasPrefix(addr, "@"):
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return "unix"
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default:
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return "tcp"
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}
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}
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// removeDeadSocket clears a socket file left behind by a process that did
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// not unlink it, which would otherwise make bind fail with EADDRINUSE
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// while nothing is listening. A socket someone IS listening on is left
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// alone, so two live nodes cannot silently steal each other's address.
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func removeDeadSocket(path string) error {
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if strings.HasPrefix(path, "@") {
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return nil // abstract sockets have no filesystem entry
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}
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fi, err := os.Stat(path)
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if err != nil {
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if os.IsNotExist(err) {
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return nil
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}
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return fmt.Errorf("stat %s: %w", path, err)
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}
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if fi.Mode()&os.ModeSocket == 0 {
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return fmt.Errorf("%s exists and is not a socket", path)
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}
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if c, err := net.DialTimeout("unix", path, 200*time.Millisecond); err == nil {
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c.Close()
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return fmt.Errorf("%s is already served by a live node", path)
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}
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return os.Remove(path)
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}
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