libpcap pcap_sendpacket support across plaatforms.

["Mark Pizzolato" <List-tcpdump-workers () subscriptions pizzolato net>]

I've been working on a system simulator (simh http://simh.trailing-edge.com)
which provides ethernet device emulation for the systems which originally
had ethernet devices (i.e. vax, pdp11 and pdp10).

The ethernet support for this package was originally implemented on Windows
with Winpcap, and then ported back to other platforms leveraging the generic
libpcap capabilities.  The only lacking piece here, from an API poinit of
view, has been pcap_sendpacket.  Just to get by, we've had platform specific
network code in the layer which uses libpcap to provide a pcap_sendpacket
for the non Windows platforms.  This only solves part of the problem since
several platforms use pcap-bpf.c or pcap-pf.c or pcap-snit.c which open the
network device O_RDONLY.  To get useful functionality on these platforms,
we've needed to hack pcap-bpf.c, or pcap-pf.c or pcap-snit.c and change
O_RDONLY to O_RDWR.  If would seem that the right thing to do is to
generically include pcap_sendpacket and the related open requirements in the
base pcap library.  To that end, the attached set of patches implementes
pcap_sendpacket where possible, and behaves reasonably otherwise.

In pcap.h, I've messed with PCA_MINOR_VERSION in  an attempt to have the
code which uses pcap.h to have a compile time means of determinig if
pcap_sendpacket is available:

#if (_WIN32) || (PCAP_MAJOR_VERSION > 2) || ((PCAP_MAJOR_VERSION == 2) &&
(PCAP_MINOR_VERSION > 4))
#define HAS_PCAP_SENDPACKET 1
#endif

Is there a better way to do this at compile time?

I've tested this patched code on platforms which use pcap-bpf.c,
pcap-linux.c, pcap-dlpi.c.

If you accept this, I'll take a stab at updating the man page as well.

Thanks.

- Mark Pizzolato

Attachment: pcap_sendpacket.patch
Description: