From c2c5918483796d477a05c03bfcc09c81dc88b30c Mon Sep 17 00:00:00 2001
From: Will Scott <will@cypherpunk.email>
Date: Fri, 26 Feb 2021 23:21:36 -0800
Subject: [PATCH] fix autonat race

fix #7947
move `BasicHost.AutoNat` to a private field (it has no public method and shouldn't be accessed afaik.
Instead add a setter for config that sets it while holding the address mutex to prevent reads of the
field at the same time.
---
 config/config.go                  |  4 +++-
 p2p/host/basic/basic_host.go      | 16 +++++++++++++---
 p2p/host/basic/basic_host_test.go |  2 +-
 3 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/config/config.go b/config/config.go
index 0871e584f4..f2377ac682 100644
--- a/config/config.go
+++ b/config/config.go
@@ -335,10 +335,12 @@ func (cfg *Config) NewNode(ctx context.Context) (host.Host, error) {
 		autonatOpts = append(autonatOpts, autonat.WithReachability(*cfg.AutoNATConfig.ForceReachability))
 	}
 
-	if h.AutoNat, err = autonat.New(ctx, h, autonatOpts...); err != nil {
+	autonat, err := autonat.New(ctx, h, autonatOpts...)
+	if err != nil {
 		h.Close()
 		return nil, fmt.Errorf("cannot enable autorelay; autonat failed to start: %v", err)
 	}
+	h.SetAutoNat(autonat)
 
 	// start the host background tasks
 	h.Start()
diff --git a/p2p/host/basic/basic_host.go b/p2p/host/basic/basic_host.go
index de5b7dfe43..1e5fa9ed0c 100644
--- a/p2p/host/basic/basic_host.go
+++ b/p2p/host/basic/basic_host.go
@@ -112,7 +112,7 @@ type BasicHost struct {
 	signKey                 crypto.PrivKey
 	caBook                  peerstore.CertifiedAddrBook
 
-	AutoNat autonat.AutoNAT
+	autoNat autonat.AutoNAT
 }
 
 var _ host.Host = (*BasicHost)(nil)
@@ -811,6 +811,7 @@ func (h *BasicHost) AllAddrs() []ma.Multiaddr {
 	h.addrMu.RLock()
 	filteredIfaceAddrs := h.filteredInterfaceAddrs
 	allIfaceAddrs := h.allInterfaceAddrs
+	autonat := h.autoNat
 	h.addrMu.RUnlock()
 
 	// Iterate over all _unresolved_ listen addresses, resolving our primary
@@ -831,8 +832,8 @@ func (h *BasicHost) AllAddrs() []ma.Multiaddr {
 	// but not have an external network card,
 	// so net.InterfaceAddrs() not has the public ip
 	// The host can indeed be dialed ！！！
-	if h.AutoNat != nil {
-		publicAddr, _ := h.AutoNat.PublicAddr()
+	if autonat != nil {
+		publicAddr, _ := autonat.PublicAddr()
 		if publicAddr != nil {
 			finalAddrs = append(finalAddrs, publicAddr)
 		}
@@ -992,6 +993,15 @@ func (h *BasicHost) AllAddrs() []ma.Multiaddr {
 	return dedupAddrs(finalAddrs)
 }
 
+// SetAutoNat sets the autonat service for the host.
+func (h *BasicHost) SetAutoNat(a autonat.AutoNAT) {
+	h.addrMu.Lock()
+	defer h.addrMu.Unlock()
+	if h.autoNat == nil {
+		h.autoNat = a
+	}
+}
+
 // Close shuts down the Host's services (network, etc).
 func (h *BasicHost) Close() error {
 	h.closeSync.Do(func() {
diff --git a/p2p/host/basic/basic_host_test.go b/p2p/host/basic/basic_host_test.go
index 3585b01b65..950e93fcf5 100644
--- a/p2p/host/basic/basic_host_test.go
+++ b/p2p/host/basic/basic_host_test.go
@@ -203,7 +203,7 @@ func TestHostAddrsFactory(t *testing.T) {
 	}
 
 	var err error
-	h.AutoNat, err = autonat.New(ctx, h, autonat.WithReachability(network.ReachabilityPublic))
+	h.autoNat, err = autonat.New(ctx, h, autonat.WithReachability(network.ReachabilityPublic))
 	if err != nil {
 		t.Fatalf("should be able to attach autonat: %v", err)
 	}