tcptraceroute 1.5b7 on Snow Leopard

[Josh Bracken]

Hi,

I'm getting nothing but "debug: null pointer from pcap_next()" after
upgrading to 10.6 and re-installing mac ports and subsequently
installing tcptraceroute. I then installed Mac Ports on a different
Mac that had shipped with 10.6 and had never had Mac Ports installed.
I get the same results on both macs. I have had zero success finding
any way to remediate this issue. I have found 2 possible causes for
this noted below:

1) on a platform where packet filtering is done in user mode rather
than the kernel, the kernel hands a buffer full of packets to libpcap
but none of them pass the filter;

2) on a platform that supports a read timeout that starts before any
packets arrive, and that causes the read/recvfrom/getmsg/whatever from
the kernel to return when the timeout expires even if no packets have
arrived, no packets arrive within the timeout interval.

My versions
----------
libpcap 1.0.0
libnet 1.1.4
tcptraceroute 1.5beta7_1


Debug output from tcptraceroute to gmail
------------------
l-s-lock:~lock$ sudo tcptraceroute -d mail.google.com 443
debug: tcptraceroute 1.5beta7, i686-apple-darwin10.0.0
debug: Compiled with libpcap 1.0.0, libnet 1.1.4 (API 110)
debug: entering getinterfaces()
debug: ifreq buffer set to 32
debug: Successfully retrieved interface list
debug: Using HAVE_SOCKADDR_SA_LEN method for finding addresses.
debug: Discovered interface lo0 with address 24.3.0.0
debug: Ignoring AF_INET6 address on interface lo0
debug: Ignoring AF_INET6 address on interface lo0
debug: Discovered interface lo0 with address 127.0.0.1
debug: Ignoring down interface gif0
debug: Ignoring down interface stf0
debug: Discovered interface en0 with address 6.3.6.0
debug: Discovered interface en0 with address 10.2.5.10
debug: Discovered interface fw1 with address 144.3.8.0
debug: Discovered interface en1 with address 6.3.6.0
debug: leaving getinterfaces()
debug: Determined source address of 10.2.5.10 to reach 74.125.127.19
debug: entering finddev()
debug: finddev() returning en0
debug: Setting o_syn, in absence of either o_syn or o_ack
debug: debugoptions():
debug:         TEXTSIZE: 1024        SNAPLEN: 92     IPTOSBUFFERS: 12
debug: ALLOCATEID_CACHE: 512        datalink: 1    datalinkoffset: 14
debug:         o_minttl: 1          o_maxttl: 30        o_timeout: 3
debug:          o_debug: 1         o_numeric: 0          o_pktlen: 0
debug:       o_nqueries: 3        o_dontfrag: 0             o_tos: 0
debug:      o_forceport: 0             o_syn: 1             o_ack: 0
debug:            o_ecn: 0        o_nofilter: 0 o_nogetinterfaces: 0
debug:      o_trackport: 0      datalinkname: ETHERNET     device: en0
debug:       o_noselect: 1            o_dnat: 0               isn: 1044160097
Selected device en0, address 10.249.58.10, port 49938 for outgoing packets
debug: pcap filter is:
		(tcp and src host 74.125.127.19 and src port 443 and dst host 10.249.58.10)
		or ((icmp[0] == 11 or icmp[0] == 3) and dst host 10.249.58.10)
Tracing the path to mail.google.com (74.125.127.19) on TCP port 443
(https), 30 hops max
debug: Generating a new batch of 512 IP ID's
debug: Sent probe 1 of 3 for hop 1, IP ID 62136, source port 49938, SYN
debug: null pointer from pcap_next()
debug: null pointer from pcap_next()
debug: null pointer from pcap_next()
debug: null pointer from pcap_next()
debug: null pointer from pcap_next()
debug: null pointer from pcap_next()
debug: null pointer from pcap_next()
debug: null pointer from pcap_next()
debug: null pointer from pcap_next()
debug: null pointer from pcap_next()
debug: null pointer from pcap_next()
debug: null pointer from pcap_next()
debug: null pointer from pcap_next()
debug: null pointer from pcap_next()

Can anyone with more understanding of libpcap elaborate on what the
problem is and if there is a possible fix?

Thanks,
Lance