Re: [PATCH 0/5] [RFC] AF_RXRPC socket family implementation

["YOSHIFUJI Hideaki / 吉藤英明" <yoshfuji@linux-ipv6.org>]

In article <10385.1171024283@redhat.com> (at Fri, 09 Feb 2007 12:31:23 +0000), David Howells <dhowells@redhat.com> says:

> YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> wrote:
> 
> > and make it sure to align on 64-bit word.
> 
> The first part of sockaddr_rxrpc is exactly 64 bits; then comes the transport
> address, so that's okay.
> 
> > This sockaddr_rxrpc{} should NOT include sockaddr_in{} directly.
> > Please use sockaddr_storage{} (or sockaddr{}, maybe),
> 
> Why can't I include sockaddr_in and sockaddr_in6 in sockaddr_rxrpc, btw?

Because it is protocol (such as ipv4 or ipv6) dependent.
You cannot use different sturcture for one address family.
You could use union, maybe.

> > > That won't work.  That would then make the address larger than the maximum
> > > size (ie: sizeof(struct sockaddr_storage)).
> > 
> > sockaddr{}, then...
> 
> But that's not big enough to hold a sockaddr_in6...

struct sockaddr_rxrpc {
 ...
 union {
   struct sockaddr rxrpc_sa;
   struct sockaddr_in rxrpc_sin;
   struct sockaddr_in6 rxrpc_sin6;
 } __attribute__((__aligned(8)__));
};

Another option would be to introduce new transport protocol such as
dccp or sctp, no?

--yoshfuji