d885f9b4b6
Implements PortPool with mutex-protected allocation, bind verification to skip ports already in use by the OS, and release-for-reuse semantics. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
64 lines
1.2 KiB
Go
64 lines
1.2 KiB
Go
package tunnel
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import (
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"fmt"
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"net"
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"sync"
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)
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// PortPool tracks available ports in a fixed range for WinBox tunnel allocation.
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type PortPool struct {
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mu sync.Mutex
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used []bool
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base int
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count int
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}
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func NewPortPool(min, max int) *PortPool {
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count := max - min + 1
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return &PortPool{
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used: make([]bool, count),
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base: min,
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count: count,
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}
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}
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// Allocate returns the next free port, verifying it can actually be bound.
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// Returns error if all ports are exhausted.
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func (pp *PortPool) Allocate() (int, error) {
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pp.mu.Lock()
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defer pp.mu.Unlock()
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for i := 0; i < pp.count; i++ {
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if pp.used[i] {
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continue
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}
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port := pp.base + i
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if !canBind(port) {
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continue
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}
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pp.used[i] = true
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return port, nil
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}
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return 0, fmt.Errorf("no ports available in range %d-%d", pp.base, pp.base+pp.count-1)
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}
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// Release returns a port to the pool.
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func (pp *PortPool) Release(port int) {
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pp.mu.Lock()
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defer pp.mu.Unlock()
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idx := port - pp.base
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if idx >= 0 && idx < pp.count {
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pp.used[idx] = false
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}
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}
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func canBind(port int) bool {
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ln, err := net.Listen("tcp", fmt.Sprintf("127.0.0.1:%d", port))
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if err != nil {
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return false
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}
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ln.Close()
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return true
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}
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