Fix a couple of struct sizes to better match declaration.
diff --git a/snmplib/transports/snmpIPv4BaseDomain.c b/snmplib/transports/snmpIPv4BaseDomain.c
index 41a6cb6..05e150b 100644
--- a/snmplib/transports/snmpIPv4BaseDomain.c
+++ b/snmplib/transports/snmpIPv4BaseDomain.c
@@ -207,7 +207,7 @@
         } else if ( t && t->flags & NETSNMP_TRANSPORT_FLAG_HOSTNAME ) {
             /* XXX: hmm...  why isn't this prefixed */
             /* assuming intentional */
-            host = netsnmp_gethostbyaddr((char *)&to->sin_addr, 4, AF_INET);
+            host = netsnmp_gethostbyaddr((char *)&to->sin_addr, sizeof(struct in_addr), AF_INET);
             return (host ? strdup(host->h_name) : NULL); 
         } else {
             snprintf(tmp, sizeof(tmp), "%s: [%s]:%hu->", prefix,
diff --git a/snmplib/transports/snmpUDPBaseDomain.c b/snmplib/transports/snmpUDPBaseDomain.c
index 58b6fde..8497f71 100644
--- a/snmplib/transports/snmpUDPBaseDomain.c
+++ b/snmplib/transports/snmpUDPBaseDomain.c
@@ -386,7 +386,7 @@
                      void **opaque, int *olength)
 {
     int             rc = -1;
-    socklen_t       fromlen = sizeof(struct sockaddr);
+    socklen_t       fromlen = sizeof(netsnmp_sockaddr_storage);
     netsnmp_indexed_addr_pair *addr_pair = NULL;
     struct sockaddr *from;