On Nov 28, 2012, at 10:47 AM, Ingo Flaschberger <i...@xip.at> wrote:
> Am 28.11.2012 19:30, schrieb david peahi: >> Many years ago the standard books on application network programming were >> based on C language. Books such as "Adventures in UNIX Network >> Programming", and Professor Comer's "Internetworking with TCP/IP Vol 3" >> detailed how to write C programs using BSD sockets where binding to a >> socket brought the program up in listening mode on an 2 tuple IP v4 IP >> address/TCP well known port. Once the program opened and bound to a socket >> "netstat -n" would show that program to be "listening" on the 2-tuple. >> >> Do today's programmers still use basic BSD socket programming? Is there an >> equivalent set of called procedures for IPv6 network application >> programming? >> >> On the practical side: Have all programmers created a 128 bit field to >> store the IPv6 address, where IPv4 programs use a 32 bit field to store the >> IP address? This would seem to be similar to the year 2000 case where >> almost all programs required auditing to see if they took into account >> dates after 1999. > > on linux/unix: if the program only opens a tcp-connection or listen on it, > it's simple. > socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP) -> socket = > socket(AF_INET6, SOCK_STREAM, IPPROTO_TCP) > You left out some structure changes an the need to use getaddrinfo()/getnameinfo() in place of get*by*(). Depending on your implementation, you might also need to make some changes to your bind() call and/or the way you iterate through the returns from getaddrinfo() calling connect(). > It's more work, to build a dual-stack program - then 2 sockets needs to be > opened and handled. > But overall - it's trivial. Not if your system properly supports IPV6_V6ONLY=false default sock opt. If you're stuck on something based on BSD or WinSock where this is broken, then, yes, you may have to open 2 sockets or at the very least make a deliberate setsockopt() call or specify the option in the socket() call. Owen
