Re: libpcap patches for DLT_SITA support

["Fulko Hew" <fulko.hew () gmail com>]

On Jan 6, 2008 3:40 PM, Guy Harris <guy () alum mit edu> wrote:

> Fulko Hew wrote:
>
> > I think the code is better when its more
> > obvious, segregated and less intrusive.
>
> I've checked into the main and 1.0 branches changes to make it even more
> segregated and less intrusive.  If pcap-linux.c was compiled with SITA
> support, very little of the regular Linux capture code was used, so I
> just removed the SITA support code from pcap-linux.c and moved it to
> pcap-sita.c, and make "--with-sita" cause libpcap to be compiled with
> pcap-sita.c rather than pcap-linux.c.
>
> In addition, pcap-sita.c was using "ulong" in cases where it wanted a
> 32-bit data type (the "l" in "ntohl()" and "htonl()" really means
> "32-bit", not "long"; the use of "l" is historical and refers to the
> fact that, on L32 and LP32 platforms, where "int" is 16 bits, you need
> "long" for 32 bits); I changed it to use the official libpcap 32-bit
> data type, bpf_u_int32, as "long" could well be 64 bits.
>
> As a site effect, I was able to at least compile the SITA code on Mac OS
> X, so I updated README.sita to note that, at least in theory, the SITA
> code might no longer require Linux.  There were some compiler warnings
> generated; I fixed those.  (To get libpcap to compile with GCC warnings,
> create a ".devel" file in the top-level source directory and re-run the
> configure script.)  There are still some warnings:
>
> ./pcap-sita.c: In function 'acn_findalldevs':
> ./pcap-sita.c:415: warning: 'port' may be used uninitialized in this
> function
> ./pcap-sita.c:414: warning: 'proto' may be used uninitialized in this
> function
> ./pcap-sita.c: At top level:
> ./pcap-sita.c:77: warning: 'errorString' defined but not used
> ./pcap-sita.c:86: warning: 'dump_interface_list' defined but not used
> ./pcap-sita.c:127: warning: 'dump_interface_list_p' defined but not used
> ./pcap-sita.c:147: warning: 'dump_unit_table' defined but not used
> ./pcap-sita.c:234: warning: 'find_nth_interface_name' defined but not used
> ./pcap-sita.c:375: warning: 'acn_freealldevs' defined but not used
>
> Does the fact that acn_freealldevs() isn't used mean that memory might
> leak?


No.  Upon reflection (although I'm still chasing my other issue)...
these routines were all test routines.

I had built a harness to easily debug/test my changes and enhancements
without having to rebuild wireshark (primarily my SITA interface discovery
mechanism) .  And in order to allow me to (easily) re-run the tests, I
needed a routine like acn_freealldevs() to allow the harness to
clean_up after itself.  In retrospect, the kernel closes all open sockets
upon normal exit, but I decided to do it the friendly way.

In conclusion, no... not being called does not infer a potential memory
leak.

But as previously mentioned, I am pursuing a different situation where
some sockets are not closed, but this only 'appears to' happen
when run on certain Linux kernels.
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