In message: <86sk2m1hsj....@ds4.des.no>
Dag-Erling Smørgrav <d...@des.no> writes:
: "M. Warner Losh" <i...@bsdimp.com> writes:
: > /*
: > * Macros to cast a struct sockaddr, or parts thereof.
: > * On architectures with strict alignment requirements, the compiler
: > * can bogusly warn about alignment problems since its static analysis
: > * is insufficient for it to know that with the APIs used, there
: > * really is no alignment issue.
: > */
:
: That's a bit harsh on the compiler, don't you think? It never pays to
: hurt the compiler's feelings :)
/*
* Macros to cast a struct sockaddr, or parts thereof. struct
* sockaddr's alginment is loose to later be cast to a sockaddr_in or
* sockaddr_in6. On architectures with strict alignment requirements,
* this leads to compiler warnings because the compiler doesn't know
* the ABI guarantees proper alignment.
*/
But this leads me to think that the right fix might be:
/*
* Structure used by kernel to store most
* addresses.
*/
struct sockaddr {
unsigned char sa_len; /* total length */
sa_family_t sa_family; /* address family */
char sa_data[14]; /* actually longer; address value */
} __aligned(4);
since that's what the ABI defines....
: > : @@ -2410,8 +2419,8 @@
: > : }
: > : reject = 0;
: > : for (j = 0; j < 16; j += 4) {
: > : - if ((*(u_int32_t
*)&sin6->sin6_addr.s6_addr[j] & *(u_int32_t *)&m6p->sin6_addr.s6_addr[j])
: > : - != *(u_int32_t
*)&a6p->sin6_addr.s6_addr[j]) {
: > : + if
((UINT32_CAST(sin6->sin6_addr.s6_addr[j]) &
UINT32_CAST(m6p->sin6_addr.s6_addr[j]))
: > : + !=
UINT32_CAST(a6p->sin6_addr.s6_addr[j])) {
: > : ++reject;
: > : break;
: > : }
: > :
: > :
: >
: > Why 16 and 4 here? What's so magical about them?
:
: 4 = bytes in a uint32_t, 16 = bytes in an ipv6 address.
Isn't that better served by 'sizeof(uint32_t)' and
'sizeof(ipv6_addr_t)'?
Warner
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