Ethereal-dev: Re: [Ethereal-dev] New dissector: IAX2 (Inter-Asterisk eXchange 2) VoIP protocol
On Jan 26, 2004, at 2:22 AM, Alastair Maw wrote:
IAX2 is a Voice-over IP protocol, supported by the open-source PBX
asterisk (www.asterisk.org). It is rapidly gaining in popularity in
the low-cost VoIP sector. It would be most useful for Ethereal to
include support for it.
I attach an IAX2 packet dissector, plus a patch for the makefiles to
compile it, in the hope that it might be included in the next release.
It didn't compile:
packet-iax2.c: In function `dissect_iax2':
packet-iax2.c:438: error: dereferencing pointer to incomplete type
packet-iax2.c:438: error: type of formal parameter 1 is incomplete
packet-iax2.c:438: error: dereferencing pointer to incomplete type
packet-iax2.c:155: warning: `iax_ies_type' defined but not used
I suspect "struct sockaddr_in" isn't defined; perhaps, on some OSes,
one of the header files that packet-iax2.c
transitive-closure-of-includes defines it, but on Mac OS X 10.3.2, I
suspect none of those header files does.
That is actually a Good Thing, as there isn't necessarily a guarantee
that a "struct sockaddr_in" has the exact same layout on all OSes!
How is the IAX_IE_APPARENT_ADDR item defined? I.e., what does the IAX2
protocol send over the wire? Note that "a 'struct sockaddr_in'" isn't
the right answer; the protocol needs to specify, for example, that it
sends over the wire:
a 1-byte address length;
a 1-byte address family code, with one of the following values:
AF_INET: 2
AF_INET6: {whatever value it uses - note that not all OSes have the
same value for AF_INET6!}
any other AF_ values it supports;
for AF_INET and AF_INET6, a 2-byte port number, in network byte order;
for AF_INET, a 4-byte IPv4 address, in network byte order, and, for
AF_INET6, a 16-byte IPv6 address;
if the item it sends over the wire looks like a 4.4BSD "struct
sockaddr", or perhaps the same but with "a 2-byte address family code,
in network byte order" instead of the 1-byte address length and 1-byte
address family code if it looks like an old-style BSD "struct
sockaddr", so that hosts with different "struct sockaddr_in" structures
can interoperate. (Maybe it doesn't do IPv6, but perhaps it
should....)
