return a structure pointer. Check whether the C compiler can handle
inline functions that return a structure pointer, not whether they can
handle inline functions that return an int, as at least some versions of
autoconf's AC_C_INLINE do.
"getifaddrs()"), after processing the list returned by SIOCGIFCONF, scan
"/proc/net/dev" for interface names, and add to the list of interfaces
entries for those interfaces, with no associated addresses (if the
interfaces were already added, with addresses, from the list returned by
SIOCGIFCONF, they won't get added again).
Clean up the error handling a bit.
whether we have "freeifaddrs()" (we don't check whether we have
"getifaddrs()", and if we have "getifaddrs()" but not "freeifaddrs()",
we're stuck with leaking memory).
Give the "any" device an instance number of INT_MAX, so it shows up
after all other non-loopback devices.
"getifaddrs()" sometimes appears to supply a destination address even
for non-point-to-point interfaces (it did so on a FreeBSD 4.1 system);
don't use the broadcast address it supplies if an interface isn't a
broadcast interface, and don't use the destination address it supplies
if an interface isn't a point-to-point interface.
If we had an error constructing the list of interfaces, don't attempt to
add the "any" device to the list.
SOL_PACKET/PACKET_STATISTICS "getsockopt()" call, on Linux kernels that
support it, to get packet statistics, so that we can report the number
of dropped packets, and always use <linux/if_packet.h> to get
definitions for PF_PACKET sockets, so that we don't depend on glibc's
header files having been updated to support all the latest shiniest
kernel features (many systems with 2.4[.x] kernels don't have a
<netpacket/packet.h> that defines "struct tpacket_stats", for example,
so we wouldn't have been able to support that kernel feature on those
systems).
live captures with a "cooked" (SOCK_DGRAM) rather than a "raw"
(SOCK_RAW) PF_PACKET socket; it includes a bunch of the fields from the
"struct sockaddr_ll" you get in a "recvfrom()", including the Ethernet
protocol field.
This requires us to rewrite the BPF program if we're stuffing it into
the kernel; as long as we're doing *ex post facto* rewriting, we might
as well also do the "ret <snaplen>" -> "ret 65535" fixup there as well,
rather than in the code generator.
when compiling on Linux, as we extracted from those copies the
definitions and declarations we need in order to dissect packets, and
put them into our own header files in the regular source directory.
./configure --enable-ipv6 (requires getaddrinfo(3) and getnameinfo(3)).
TODO: make it work even without getaddrinfo(3) or getnameinfo(3)
(or, tcpdump/configure.in should provide alternative version by
AC_REPLACE_FUNCS)
TODO: make IPv6 filtering code work by default
TODO: make "protochain" friendly with optimization
guy