siphash24: change result argument to uint64_t

Change the "out" parameter from uint8_t[8] to uint64_t. On architectures which
enforce pointer alignment this fixes crashes when we previously cast an
unaligned array to uint64_t*, and on others this should at least improve
performance as the compiler now aligns these properly.

This also simplifies the code in most cases by getting rid of typecasts. The
only place which we can't change is struct duid's en.id, as that is _packed_
and public API, so we can't enforce alignment of the "id" field and have to
use memcpy instead.

1 files changed, 3 insertions, 3 deletions

diff --git a/src/libsystemd-network/sd-ipv4ll.c b/src/libsystemd-network/sd-ipv4ll.c
index 0d915e20e7..e69b1864d7 100644
--- a/src/libsystemd-network/sd-ipv4ll.c
+++ b/src/libsystemd-network/sd-ipv4ll.c
@@ -143,15 +143,15 @@ int sd_ipv4ll_set_mac(sd_ipv4ll *ll, const struct ether_addr *addr) {
         assert_return(ll, -EINVAL);
 
         if (!ll->random_data) {
-                uint8_t seed[8];
+                uint64_t seed;
 
                 /* If no random data is set, generate some from the MAC */
-                siphash24(seed, &addr->ether_addr_octet,
+                siphash24(&seed, &addr->ether_addr_octet,
                           ETH_ALEN, HASH_KEY.bytes);
 
                 assert_cc(sizeof(unsigned) <= 8);
 
-                r = sd_ipv4ll_set_address_seed(ll, *(unsigned*)seed);
+                r = sd_ipv4ll_set_address_seed(ll, (unsigned)seed);
                 if (r < 0)
                         return r;
         }