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/windows/win_sockaddr.c b/src/platform/windows/win_sockaddr.c
index 0fa6dd51..f66542c6 100644
--- a/src/platform/windows/win_sockaddr.c
+++ b/src/platform/windows/win_sockaddr.c
@@ -20,6 +20,9 @@ nni_win_nn2sockaddr(SOCKADDR_STORAGE *ss, const nni_sockaddr *sa)
 	SOCKADDR_IN * sin;
 	SOCKADDR_IN6 *sin6;
 
+	if ((ss == NULL) || (sa == NULL)) {
+		return (-1);
+	}
 	switch (sa->s_un.s_family) {
 	case NNG_AF_INET:
 		sin = (void *) ss;
@@ -46,6 +49,9 @@ nni_win_sockaddr2nn(nni_sockaddr *sa, const SOCKADDR_STORAGE *ss)
 	SOCKADDR_IN * sin;
 	SOCKADDR_IN6 *sin6;
 
+	if ((ss == NULL) || (sa == NULL)) {
+		return (-1);
+	}
 	switch (ss->ss_family) {
 	case PF_INET:
 		sin                     = (void *) ss;