NATMap mapping failed, resulting in an observed address error

[wlynxg]

Version Information

github.com/libp2p/go-libp2p v0.37.0

I found that my libp2p node's address list had a NATMap address with port 0 and an observed address with port 0.

2024-11-21T09:15:44.482Z        DEBUG   net/identify    identify/id.go:486      sending snapshot        {"seq": 7, "protocols": ["/ipfs/id/1.0.0","/ipfs/id/push/1.0.0","/ipfs/ping/1.0.0","/libp2p/circuit/relay/0.2.0/stop"], "addrs": [...,"/ip4/100.64.138.163/tcp/0","/ip4/100.64.138.163/udp/0/quic-v1/webtransport/certhash/uEiAO2S9URsYyw-LBGIJytw3zQbw8pvXgomESq3PLp31PVg/certhash/uEiCxf6Zi2SitEayX9jE50_APDrBMbfR5m-U6F7HcBMnkFw","/ip4/{observed ip}/tcp/0",...]}

At the same time, I found that my NAT mapping had the following error due to too many mapped addresses:

2024-11-21T09:15:42.049Z        WARN    nat     nat/nat.go:239  failed to establish port mapping: SOAP fault. Code: s:Client | Explanation: UPnPError | Detail: <UPnPError xmlns="urn:schemas-upnp-org:control-1-0"><errorCode>501</errorCode><errorDescription>Port mapping table id full !</errorDescription></UPnPError>

After debugging, I found that the problem is caused by:

1. When NAT mapping fails, port 0 will be returned
   

   go-libp2p/p2p/net/nat/nat.go

   Line 245 in 288868c

   return 0

2. When basic_host calls AllAddrs, it gets the mapping address from natmgr, and natmrg gets the mapping address from nat. However, nat does not determine the mapping failure, resulting in port 0 being returned.
   

   go-libp2p/p2p/host/basic/basic_host.go

   Line 902 in 288868c

   extMaddr := h.natmgr.GetMapping(listen)

   
   

   go-libp2p/p2p/host/basic/natmgr.go

   Line 269 in 288868c

   extAddr, ok := nmgr.nat.GetMapping(protocol, port)

   
   

   go-libp2p/p2p/net/nat/nat.go

   Line 110 in 288868c

   if !found {

3. basic_host replaces the port observed by the observed address with 0
   

   go-libp2p/p2p/host/basic/basic_host.go

   Line 943 in 288868c

   _, extMaddrNoIP := ma.SplitFirst(extMaddr)

   
   

   go-libp2p/p2p/host/basic/basic_host.go

   Line 952 in 288868c

   finalAddrs = append(finalAddrs, ma.Join(ip, extMaddrNoIP))