struct sockaddr * and alignment
qing.li at bluecoat.com
Tue Feb 9 18:09:03 UTC 2010
> Sure enough, that fixes this warning. Yea. But, sadly, it causes
> other problems. If you look at sbin/atm/atmconfig/natm.c you'll see
> code like:
> static void
> store_route(struct rt_msghdr *rtm)
> char *cp
> struct sockaddr *sa;
> cp = (char *)(rtm + 1);
> sa = (struct sockaddr *)cp;
> cp += roundup(sa->sa_len, sizeof(long));
> which breaks because we're now casting from an __aligned(1) char * to
> an __aligned(8) sockaddr *.
> And it is only rounding the size of the structure to long, rather than
> int64 like sockaddr_storage suggests is the proper alignment. But I
> haven't looked in the kernel to see if there's an issue there with
> routing sockets or not.
In the kernel route.h, the macro SA_SIZE is used by the routing socket
code and may the root of the problem.
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