net: decode setsockopt() multicast arguments

* configure.ac (AC_CHECK_FUNCS): Add inet_pton.
* net.c (print_mreq, print_mreq6): New functions.
(print_setsockopt): Use them to decode IP_ADD_MEMBERSHIP,
IP_DROP_MEMBERSHIP, IPV6_ADD_MEMBERSHIP, IPV6_DROP_MEMBERSHIP,
IPV6_JOIN_ANYCAST, and IPV6_LEAVE_ANYCAST.
* tests/ip_mreq.c: New file.
* tests/ip_mreq.expected: Likewise.
* tests/ip_mreq.test: New test.
* tests/Makefile.am (check_PROGRAMS): Add ip_mreq.
(TESTS): Add ip_mreq.test.
(EXTRA_DIST): ip_mreq.expected.
* tests/.gitignore: Add ip_mreq.

Based on patch by Ben Noordhuis <info@bnoordhuis.nl>.
7 files changed