From 0e31316261e47922c0575bfdcb7fc7f8df730560 Mon Sep 17 00:00:00 2001
From: Steven Allen <steven@stebalien.com>
Date: Thu, 16 Aug 2018 15:56:03 -0700
Subject: [PATCH] only map *usable* addresses
Otherwise, we'll try to port-map localhost.
---
nat.go | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)
diff --git a/nat.go b/nat.go
index d68aca0..0c47a4c 100644
--- a/nat.go
+++ b/nat.go
@@ -3,6 +3,7 @@ package nat
import (
"errors"
"fmt"
+ "net"
"strconv"
"strings"
"sync"
@@ -125,15 +126,40 @@ func (nat *NAT) NewMapping(maddr ma.Multiaddr) (Mapping, error) {
return nil, fmt.Errorf("DialArgs failed on addr: %s", maddr.String())
}
+ var ip net.IP
switch network {
case "tcp", "tcp4", "tcp6":
+ addr, err := net.ResolveTCPAddr(network, addr)
+ if err != nil {
+ return nil, err
+ }
+ ip = addr.IP
network = "tcp"
case "udp", "udp4", "udp6":
+ addr, err := net.ResolveUDPAddr(network, addr)
+ if err != nil {
+ return nil, err
+ }
+ ip = addr.IP
network = "udp"
default:
return nil, fmt.Errorf("transport not supported by NAT: %s", network)
}
+ // XXX: Known limitation: doesn't handle multiple internal addresses.
+ // If this applies to you, you can figure it out yourself. Ideally, the
+ // NAT library would allow us to handle this case but the "go way"
+ // appears to be to just "shrug" at edge-cases.
+ if !ip.IsUnspecified() {
+ internalAddr, err := nat.nat.GetInternalAddress()
+ if err != nil {
+ return nil, fmt.Errorf("failed to discover address on nat: %s", err)
+ }
+ if !ip.Equal(internalAddr) {
+ return nil, fmt.Errorf("nat address is %s, refusing to map %s", internalAddr, ip)
+ }
+ }
+
intports := strings.Split(addr, ":")[1]
intport, err := strconv.Atoi(intports)
if err != nil {
--
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