bss_dgram.c: more elegant solution to PR#2069. Use socklen_t heuristic

from b_sock.c, don't assume that caller always passes pointer to buffer
large enough to hold sockaddr_storage.
PR: 2069

crypto/bio/bss_dgram.c

@@ -108,11 +108,13 @@ static BIO_METHOD methods_dgramp=
 
 typedef struct bio_dgram_data_st
 	{
+	union {
+		struct sockaddr sa;
+		struct sockaddr_in sa_in;
 #if OPENSSL_USE_IPV6
-	struct sockaddr_storage peer;
-#else
-	struct sockaddr_in peer;
+		struct sockaddr_in6 sa_in6;
 #endif
+	} peer;
 	unsigned int connected;
 	unsigned int _errno;
 	unsigned int mtu;
@@ -278,28 +280,38 @@ static int dgram_read(BIO *b, char *out, int outl)
 	int ret=0;
 	bio_dgram_data *data = (bio_dgram_data *)b->ptr;
 
+	struct	{
+	/*
+	 * See commentary in b_sock.c. <appro>
+	 */
+	union	{ size_t s; int i; } len;
+	union	{
+		struct sockaddr sa;
+		struct sockaddr_in sa_in;
 #if OPENSSL_USE_IPV6
-	struct sockaddr_storage peer;
-#else
-	struct sockaddr_in peer;
+		struct sockaddr_in6 sa_in6;
 #endif
-	int peerlen = sizeof(peer);
+		} peer;
+	} sa;
+
+	sa.len.s=0;
+	sa.len.i=sizeof(sa.peer);
 
 	if (out != NULL)
 		{
 		clear_socket_error();
-		memset(&peer, 0x00, peerlen);
-		/* Last arg in recvfrom is signed on some platforms and
-		 * unsigned on others. It is of type socklen_t on some
-		 * but this is not universal. Cast to (void *) to avoid
-		 * compiler warnings.
-		 */
+		memset(&sa.peer, 0x00, sizeof(sa.peer));
 		dgram_adjust_rcv_timeout(b);
-		ret=recvfrom(b->num,out,outl,0,(struct sockaddr *)&peer,(void *)&peerlen);
+		ret=recvfrom(b->num,out,outl,0,&sa.peer.sa,(void *)&sa.len);
+		if (sizeof(sa.len.i)!=sizeof(sa.len.s) && sa.len.i==0)
+			{
+			OPENSSL_assert(sa.len.s<=sizeof(sa.peer));
+			sa.len.i = (int)sa.len.s;
+			}
 		dgram_reset_rcv_timeout(b);
 
 		if ( ! data->connected  && ret >= 0)
-			BIO_ctrl(b, BIO_CTRL_DGRAM_SET_PEER, 0, &peer);
+			BIO_ctrl(b, BIO_CTRL_DGRAM_SET_PEER, 0, &sa.peer);
 
 		BIO_clear_retry_flags(b);
 		if (ret < 0)
@@ -323,25 +335,10 @@ static int dgram_write(BIO *b, const char *in, int inl)
 	if ( data->connected )
 		ret=writesocket(b->num,in,inl);
 	else
-#if OPENSSL_USE_IPV6
-		if (data->peer.ss_family == AF_INET)
 #if defined(NETWARE_CLIB) && defined(NETWARE_BSDSOCK)
-			ret=sendto(b->num, (char *)in, inl, 0, (const struct sockaddr *)&data->peer, sizeof(struct sockaddr_in));
+		ret=sendto(b->num, (char *)in, inl, 0, &data->peer.sa, sizeof(data->peer));
 #else
-			ret=sendto(b->num, in, inl, 0, (const struct sockaddr *)&data->peer, sizeof(struct sockaddr_in));
-#endif
-		else
-#if defined(NETWARE_CLIB) && defined(NETWARE_BSDSOCK)
-			ret=sendto(b->num, (char *)in, inl, 0, (const struct sockaddr *)&data->peer, sizeof(struct sockaddr_in6));
-#else
-			ret=sendto(b->num, in, inl, 0, (const struct sockaddr *)&data->peer, sizeof(struct sockaddr_in6));
-#endif
-#else
-#if defined(NETWARE_CLIB) && defined(NETWARE_BSDSOCK)
-		ret=sendto(b->num, (char *)in, inl, 0, (const struct sockaddr *)&data->peer, sizeof(struct sockaddr_in));
-#else
-		ret=sendto(b->num, in, inl, 0, (const struct sockaddr *)&data->peer, sizeof(struct sockaddr_in));
-#endif
+		ret=sendto(b->num, in, inl, 0, &data->peer.sa, sizeof(data->peer));
 #endif
 
 	BIO_clear_retry_flags(b);
@@ -428,11 +425,20 @@ static long dgram_ctrl(BIO *b, int cmd, long num, void *ptr)
 		else
 			{
 #endif
+			switch (to->sa_family)
+				{
+				case AF_INET:
+					memcpy(&data->peer,to,sizeof(data->peer.sa_in));
+					break;
 #if OPENSSL_USE_IPV6
-			memcpy(&(data->peer),to, sizeof(struct sockaddr_storage));
-#else
-			memcpy(&(data->peer),to, sizeof(struct sockaddr_in));
+				case AF_INET6:
+					memcpy(&data->peer,to,sizeof(data->peer.sa_in6));
+					break;
 #endif
+				default:
+					memcpy(&data->peer,to,sizeof(data->peer.sa));
+					break;
+				}
 #if 0
 			}
 #endif
@@ -537,41 +543,60 @@ static long dgram_ctrl(BIO *b, int cmd, long num, void *ptr)
 		if ( to != NULL)
 			{
 			data->connected = 1;
+			switch (to->sa_family)
+				{
+				case AF_INET:
+					memcpy(&data->peer,to,sizeof(data->peer.sa_in));
+					break;
 #if OPENSSL_USE_IPV6
-			memcpy(&(data->peer),to, sizeof(struct sockaddr_storage));
-#else
-			memcpy(&(data->peer),to, sizeof(struct sockaddr_in));
+				case AF_INET6:
+					memcpy(&data->peer,to,sizeof(data->peer.sa_in6));
+					break;
 #endif
+				default:
+					memcpy(&data->peer,to,sizeof(data->peer.sa));
+					break;
+				}
 			}
 		else
 			{
 			data->connected = 0;
-#if OPENSSL_USE_IPV6
-			memset(&(data->peer), 0x00, sizeof(struct sockaddr_storage));
-#else
-			memset(&(data->peer), 0x00, sizeof(struct sockaddr_in));
-#endif
+			memset(&(data->peer), 0x00, sizeof(data->peer));
 			}
 		break;
 	case BIO_CTRL_DGRAM_GET_PEER:
 		to = (struct sockaddr *) ptr;
-
+		switch (to->sa_family)
+			{
+			case AF_INET:
+				memcpy(to,&data->peer,(ret=sizeof(data->peer.sa_in)));
+				break;
 #if OPENSSL_USE_IPV6
-		memcpy(to, &(data->peer), sizeof(struct sockaddr_storage));
-		ret = sizeof(struct sockaddr_storage);
-#else
-		memcpy(to, &(data->peer), sizeof(struct sockaddr_in));
-		ret = sizeof(struct sockaddr_in);
+			case AF_INET6:
+				memcpy(to,&data->peer,(ret=sizeof(data->peer.sa_in6)));
+				break;
 #endif
+			default:
+				memcpy(to,&data->peer,(ret=sizeof(data->peer.sa)));
+				break;
+			}
 		break;
 	case BIO_CTRL_DGRAM_SET_PEER:
 		to = (struct sockaddr *) ptr;
-
+		switch (to->sa_family)
+			{
+			case AF_INET:
+				memcpy(&data->peer,to,sizeof(data->peer.sa_in));
+				break;
 #if OPENSSL_USE_IPV6
-		memcpy(&(data->peer), to, sizeof(struct sockaddr_storage));
-#else
-		memcpy(&(data->peer), to, sizeof(struct sockaddr_in));
+			case AF_INET6:
+				memcpy(&data->peer,to,sizeof(data->peer.sa_in6));
+				break;
 #endif
+			default:
+				memcpy(&data->peer,to,sizeof(data->peer.sa));
+				break;
+			}
 		break;
 	case BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT:
 		memcpy(&(data->next_timeout), ptr, sizeof(struct timeval));