Issue #8368 has been reported by akr (Akira Tanaka). ---------------------------------------- Feature #8368: Socket.getifaddrs https://bugs.ruby-lang.org/issues/8368 Author: akr (Akira Tanaka) Status: Open Priority: Normal Assignee: Category: Target version: I'd like to add a method: Socket.getifaddrs. This method is a wrapper to getifaddrs() function. The result is an array of instances of Socket::Ifaddr class as follows. % ./ruby -rpp -rsocket -e 'pp Socket.getifaddrs' [#<Socket::Ifaddr lo UP,LOOPBACK,RUNNING,0x10000 [PACKET protocol:0 lo hatype:772 HOST hwaddr:00:00:00:00:00:00]>, #<Socket::Ifaddr eth0 UP,BROADCAST,RUNNING,MULTICAST,0x10000 [PACKET protocol:0 eth0 hatype:1 HOST hwaddr:00:16:3e:95:88:bb] broadcast:[PACKET protocol:0 eth0 hatype:1 HOST hwaddr:ff:ff:ff:ff:ff:ff]>, #<Socket::Ifaddr sit0 NOARP [PACKET protocol:0 sit0 hatype:776 HOST hwaddr:00:00:00:00]>, #<Socket::Ifaddr lo UP,LOOPBACK,RUNNING,0x10000 [127.0.0.1] netmask:[255.0.0.0]>, #<Socket::Ifaddr eth0 UP,BROADCAST,RUNNING,MULTICAST,0x10000 [221.186.184.67] netmask:[255.255.255.240] broadcast:[221.186.184.79]>, #<Socket::Ifaddr lo UP,LOOPBACK,RUNNING,0x10000 [::1] netmask:[ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff]>, #<Socket::Ifaddr eth0 UP,BROADCAST,RUNNING,MULTICAST,0x10000 [fe80::216:3eff:fe95:88bb%eth0] netmask:[ffff:ffff:ffff:ffff::]>] This method can be used to choose multicast-enabled interfaces. Multicast applications needs to identify a such interface to sending a multicast datagram. % ./ruby -rpp -rsocket -e ' pp Socket.getifaddrs.reject {|ifaddr| !ifaddr.addr.ip? || (ifaddr.flags & Socket::IFF_MULTICAST == 0) }.map {|ifaddr| [ifaddr.name, ifaddr.ifindex, ifaddr.addr] }' [["eth0", 2, #<Addrinfo: 221.186.184.67>], ["eth0", 2, #<Addrinfo: fe80::216:3eff:fe95:88bb%eth0>]] This method can be used to obtain broadcast addresses to send a broadcast messages. (use case: [ruby-talk:329921]) Also, the broadcast addresses can be used to receive broadcast messages. (Programming UNIX Sockets in C: 4.12. How can I write a multi-homed server? http://www.faqs.org/faqs/unix-faq/socket/ ) getifaddrs() is not standardized but many platforms have. BSDI, FreeBSD, NetBSD, OpenBSD, DragonFly, MirOS, GNU/Linux, MacOS X, SunOS 5.11 (OpenIndiana), Cygwin 1.7.15 From Gnulib document, getifaddrs() is not exist on AIX 5.1, HP-UX 11, IRIX 6.5, OSF/1 5.1, Solaris 10, Cygwin 1.5.x, mingw, MSVC 9, Interix 3.5, BeOS. http://www.gnu.org/software/gnulib/manual/html_node/getifaddrs.html I implemented new Socket::Ifaddr class for return value of Socket.getifaddrs, instead of constructing the result from currentn data structures such as Array. This choice make us possible to implement Socket::Ifaddr#inspect to show flags as its names (UP,...). Also, struct getifaddrs contains Address-specific data, ifa_data which may be extended by platforms. When we find a way to extract some data from ifa_data, we can add a method for that. Socket::Ifaddr is different from Socket::Interface by http://bugs.ruby-lang.org/issues/8075 . They have no one-to-one mapping. For example, Socket.getifaddrs returns two or more elements for one interface. -- http://bugs.ruby-lang.org/