Clarify XORMapped panic case (#877)

This commit is contained in:
Misha Bragin 2023-05-18 19:47:36 +02:00 committed by GitHub
parent 8a8c4bdddd
commit 8b78209ae5
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2 changed files with 9 additions and 6 deletions

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@ -1,8 +1,9 @@
package main package main
import ( import (
"github.com/netbirdio/netbird/client/cmd"
"os" "os"
"github.com/netbirdio/netbird/client/cmd"
) )
func main() { func main() {

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@ -209,7 +209,7 @@ func (m *UniversalUDPMuxDefault) GetXORMappedAddr(serverAddr net.Addr, deadline
// otherwise, make a STUN request to discover the address // otherwise, make a STUN request to discover the address
// or wait for already sent request to complete // or wait for already sent request to complete
waitAddrReceived, err := m.sendStun(serverAddr) waitAddrReceived, err := m.sendSTUN(serverAddr)
if err != nil { if err != nil {
return nil, fmt.Errorf("%s: %s", "failed to send STUN packet", err) return nil, fmt.Errorf("%s: %s", "failed to send STUN packet", err)
} }
@ -221,8 +221,10 @@ func (m *UniversalUDPMuxDefault) GetXORMappedAddr(serverAddr net.Addr, deadline
var addr *stun.XORMappedAddress var addr *stun.XORMappedAddress
m.mu.Lock() m.mu.Lock()
// A very odd case that mappedAddr is nil. // A very odd case that mappedAddr is nil.
// But can happen when the deadline property is larger than params.XORMappedAddrCacheTTL. // Can happen when the deadline property is larger than params.XORMappedAddrCacheTTL.
// We protect the code from panic. // Or when we don't receive a response to our m.sendSTUN request (the response is handled asynchronously) and
// the XORMapped expires meanwhile triggering a closure of the waitAddrReceived channel.
// We protect the code from panic here.
if mappedAddr, ok := m.xorMappedMap[serverAddr.String()]; ok { if mappedAddr, ok := m.xorMappedMap[serverAddr.String()]; ok {
addr = mappedAddr.addr addr = mappedAddr.addr
} }
@ -236,11 +238,11 @@ func (m *UniversalUDPMuxDefault) GetXORMappedAddr(serverAddr net.Addr, deadline
} }
} }
// sendStun sends a STUN request via UDP conn. // sendSTUN sends a STUN request via UDP conn.
// //
// The returned channel is closed when the STUN response has been received. // The returned channel is closed when the STUN response has been received.
// Method is safe for concurrent use. // Method is safe for concurrent use.
func (m *UniversalUDPMuxDefault) sendStun(serverAddr net.Addr) (chan struct{}, error) { func (m *UniversalUDPMuxDefault) sendSTUN(serverAddr net.Addr) (chan struct{}, error) {
m.mu.Lock() m.mu.Lock()
defer m.mu.Unlock() defer m.mu.Unlock()