pcpserver does not handle all-zeroes IPv4 external address correctly

[ppuryear]

I recently updated my home router to a firmware that uses miniupnpd 1.8.20140401. I immediately began seeing messages like this in the system log:

Apr 20 03:32:10 miniupnpd[474]: PCP: External IP in request didn't match interface IP

After recompiling miniupnpd with -DDEBUG, I got this information:

Apr 20 03:32:10 miniupnpd[474]: PCP request received from 192.168.1.224:5353 60bytes
Apr 20 03:32:10 miniupnpd[474]: PCP MAP: v2 Opcode specific information.
Apr 20 03:32:10 miniupnpd[474]: MAP nonce:      70ec7ba6133c3dda59e45bc2
Apr 20 03:32:10 miniupnpd[474]: MAP protocol:   17
Apr 20 03:32:10 miniupnpd[474]: MAP int port:   16402
Apr 20 03:32:10 miniupnpd[474]: MAP ext port:   55709
Apr 20 03:32:10 miniupnpd[474]: MAP Ext IP:     ::ffff:0.0.0.0
Apr 20 03:32:10 miniupnpd[474]: PCP: External IP in request didn't match interface IP 
Apr 20 03:32:10 miniupnpd[474]: Interface IP ::ffff:xx.xxx.xx.xx
Apr 20 03:32:10 miniupnpd[474]: IP in the PCP request ::ffff:0.0.0.0 

(where the x's are my public IPv4 address). So miniupnpd is complaining about a MAP request using the all-zeroes IPv4 suggested external address ::ffff:0.0.0.0 (see http://tools.ietf.org/html/rfc6887#section-5).

Looking at the code, it looks like CheckExternalAddress uses IN6_IS_ADDR_UNSPECIFIED to check for all-zeroes addresses. However, that macro only works for actual IPv6 addresses, not IPv6-mapped IPv4 addresses (it essentially just checks that all 16 bytes of the address are zero).

[miniupnp]

thanks for reporting the problem.
Do you know which software is requesting the maping using PCP ?

[ppuryear]

It appears to be OS X Messages and iOS iMessage/Facetime. Cold-starting Messages on my Macbook reliably generates the request.