Improve UDP test coverage, fix numerous issues found.

We introduced richer, deeper tests for UDP functionality.
These tests uncovered a number of issues which this commit fixes.

The Windows IOCP code needs to support multiple aios on a single
nni_win_event.  A redesign of the IOCP handling addresses that.

The POSIX UDP code also needed fixes; foremost among them is the
fact that the UDP file descriptor is not placed into non-blocking
mode, leading to potential hangs.

A number of race conditions and bugs along the implementation of
the above items were uncovered and fixed.  To the best of our knowledge
the current code is bug-free.

1 files changed, 6 insertions, 0 deletions

diff --git a/src/platform/posix/posix_sockaddr.c b/src/platform/posix/posix_sockaddr.c
index ea630b01..25953f50 100644
--- a/src/platform/posix/posix_sockaddr.c
+++ b/src/platform/posix/posix_sockaddr.c
@@ -33,6 +33,9 @@ nni_posix_nn2sockaddr(void *sa, const nni_sockaddr *na)
 	const nng_sockaddr_path *nspath;
 	size_t                   sz;
 
+	if ((sa == NULL) || (na == NULL)) {
+		return (-1);
+	}
 	switch (na->s_un.s_family) {
 	case NNG_AF_INET:
 		sin  = (void *) sa;
@@ -80,6 +83,9 @@ nni_posix_sockaddr2nn(nni_sockaddr *na, const void *sa)
 	nng_sockaddr_in6 *         nsin6;
 	nng_sockaddr_path *        nspath;
 
+	if ((na == NULL) || (sa == NULL)) {
+		return (-1);
+	}
 	switch (((struct sockaddr *) sa)->sa_family) {
 	case AF_INET:
 		sin             = (void *) sa;