Since `sa_len' describes the size of a `sockaddr' (or one of its
derivatives) /including/ `sa_len' (maybe I am wrong, but this is my
interpretation of the comment `total length' that appears near the
definition of `struct sockaddr' in <sys/socket.h>), `sa_len' just
cannot be zero.
Yes, it can not be zero.
The current definition of ROUNDUP() might hide a bug. In addition, on
some machines, it disturbs the pipeline of the CPU by introducing a
branch (for no real reason, as it seems, while I might be
nitpicking). At very least, it looks confusing.
The following patch amends the issue:
Index: route.c
===================================================================
RCS file: /cvs/src/sys/net/route.c,v
retrieving revision 1.387
diff -u -p -r1.387 route.c
--- route.c 24 Jun 2019 22:26:25 -0000 1.387
+++ route.c 14 Jul 2019 10:05:04 -0000
@@ -138,7 +138,7 @@
#include <net/bfd.h>
#endif
-#define ROUNDUP(a) (a>0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) :
sizeof(long))
+#define ROUNDUP(a) (1 + (((a) - 1) | (sizeof(long) - 1)))
/* Give some jitter to hash, to avoid synchronization between routers. */
static uint32_t rt_hashjitter;
