After re-reading this thread, I think what Dave didn't like about the
original definition of sockaddr_storage was the unnecessary use of
_more_than_1_ pad field and the align field. So, the simplest
definition that Dave might approve would be:
#define _SS_MAXSIZE 128 /* Implementation specific max size */
struct sockaddr_storage {
sa_family_t ss_family;
char __data[_SS_MAXSIZE - sizeof(sa_family_t)];
} __attribute __ ((aligned(sizeof(struct sockaddr *))));
The use of the 'sizeof(struct sockaddr *)' for specifying the required
alignment is just to illustrate the second criteria for this structure
as documented in the RFC, i.e. "It is aligned at an appropriate boundary
so protocol specific socket address data structure pointers can be cast
to it and access their fields without alignment problems...".
I'll resubmit a patch tomorrow with the above definition if there are no
objections.
Bruce Allan
Jon Grimm wrote:
Bruce,
I removed Dave from the the cc list until we get something that
works for us (or anyone else that wants to chime in).
My second proposal doesn't look quite right when I reread it.
See below.
Thanks,
Jon
Jon Grimm wrote:
Or if you don't care about the alignment of the __data field at all:
#define _SS_MAXSIZE 128
#if ULONG_MAX > 0xffffffff
#define _ALIGNSIZE ((sizeof(__u64)))
#else
#define _ALIGNSIZE ((sizeof(__u32)))
#endif
struct sockaddr_storage {
sa_family_t ss_family;
char __data[_SS_MAXSIZE-sizeof(sa_family_t)*2 +
_ALIGNSIZE];
Should be
char __data[__SS_MAXSIZE-ALIGNSIZE];
} __attribute ((aligned(_ALIGNSIZE)));
jon
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