rxrpc: Use IPv4 addresses throught the IPv6

AF_RXRPC opens an IPv6 socket through which to send and receive network
packets, both IPv6 and IPv4.  It currently turns AF_INET addresses into
AF_INET-as-AF_INET6 addresses based on an assumption that this was
necessary; on further inspection of the code, however, it turns out that
the IPv6 code just farms packets aimed at AF_INET addresses out to the IPv4
code.

Fix AF_RXRPC to use AF_INET addresses directly when given them.

Fixes: 7b674e390e51 ("rxrpc: Fix IPv6 support")
Signed-off-by: David Howells <dhowells@redhat.com>

4 files changed, 17 insertions, 22 deletions

diff --git a/net/rxrpc/af_rxrpc.c b/net/rxrpc/af_rxrpc.c
index ac44d8afffb1..2fdd276f6842 100644
--- a/net/rxrpc/af_rxrpc.c
+++ b/net/rxrpc/af_rxrpc.c
@@ -97,7 +97,8 @@ static int rxrpc_validate_address(struct rxrpc_sock *rx,
 	    srx->transport_len > len)
 		return -EINVAL;
 
-	if (srx->transport.family != rx->family)
+	if (srx->transport.family != rx->family &&
+	    srx->transport.family == AF_INET && rx->family != AF_INET6)
 		return -EAFNOSUPPORT;
 
 	switch (srx->transport.family) {
diff --git a/net/rxrpc/conn_object.c b/net/rxrpc/conn_object.c
index 885dae829f4a..fb856a1ccda8 100644
--- a/net/rxrpc/conn_object.c
+++ b/net/rxrpc/conn_object.c
@@ -89,8 +89,9 @@ struct rxrpc_connection *rxrpc_find_connection_rcu(struct rxrpc_local *local,
 	if (rxrpc_extract_addr_from_skb(local, &srx, skb) < 0)
 		goto not_found;
 
-	/* We may have to handle mixing IPv4 and IPv6 */
-	if (srx.transport.family != local->srx.transport.family) {
+	if (srx.transport.family != local->srx.transport.family &&
+	    (srx.transport.family == AF_INET &&
+	     local->srx.transport.family != AF_INET6)) {
 		pr_warn_ratelimited("AF_RXRPC: Protocol mismatch %u not %u\n",
 				    srx.transport.family,
 				    local->srx.transport.family);
diff --git a/net/rxrpc/peer_event.c b/net/rxrpc/peer_event.c
index f3e6fc670da2..81a7869325a6 100644
--- a/net/rxrpc/peer_event.c
+++ b/net/rxrpc/peer_event.c
@@ -47,6 +47,8 @@ static struct rxrpc_peer *rxrpc_lookup_peer_icmp_rcu(struct rxrpc_local *local,
 	 */
 	switch (srx->transport.family) {
 	case AF_INET:
+		srx->transport_len = sizeof(srx->transport.sin);
+		srx->transport.family = AF_INET;
 		srx->transport.sin.sin_port = serr->port;
 		switch (serr->ee.ee_origin) {
 		case SO_EE_ORIGIN_ICMP:
@@ -70,20 +72,20 @@ static struct rxrpc_peer *rxrpc_lookup_peer_icmp_rcu(struct rxrpc_local *local,
 
 #ifdef CONFIG_AF_RXRPC_IPV6
 	case AF_INET6:
-		srx->transport.sin6.sin6_port = serr->port;
 		switch (serr->ee.ee_origin) {
 		case SO_EE_ORIGIN_ICMP6:
 			_net("Rx ICMP6");
+			srx->transport.sin6.sin6_port = serr->port;
 			memcpy(&srx->transport.sin6.sin6_addr,
 			       skb_network_header(skb) + serr->addr_offset,
 			       sizeof(struct in6_addr));
 			break;
 		case SO_EE_ORIGIN_ICMP:
 			_net("Rx ICMP on v6 sock");
-			srx->transport.sin6.sin6_addr.s6_addr32[0] = 0;
-			srx->transport.sin6.sin6_addr.s6_addr32[1] = 0;
-			srx->transport.sin6.sin6_addr.s6_addr32[2] = htonl(0xffff);
-			memcpy(srx->transport.sin6.sin6_addr.s6_addr + 12,
+			srx->transport_len = sizeof(srx->transport.sin);
+			srx->transport.family = AF_INET;
+			srx->transport.sin.sin_port = serr->port;
+			memcpy(&srx->transport.sin.sin_addr,
 			       skb_network_header(skb) + serr->addr_offset,
 			       sizeof(struct in_addr));
 			break;
diff --git a/net/rxrpc/utils.c b/net/rxrpc/utils.c
index e801171fa351..017adaa54e90 100644
--- a/net/rxrpc/utils.c
+++ b/net/rxrpc/utils.c
@@ -25,20 +25,11 @@ int rxrpc_extract_addr_from_skb(struct rxrpc_local *local,
 
 	switch (ntohs(skb->protocol)) {
 	case ETH_P_IP:
-		if (local->srx.transport.family == AF_INET6) {
-			srx->transport_type = SOCK_DGRAM;
-			srx->transport_len = sizeof(srx->transport.sin6);
-			srx->transport.sin6.sin6_family = AF_INET6;
-			srx->transport.sin6.sin6_port = udp_hdr(skb)->source;
-			srx->transport.sin6.sin6_addr.s6_addr32[2] = htonl(0xffff);
-			srx->transport.sin6.sin6_addr.s6_addr32[3] = ip_hdr(skb)->saddr;
-		} else {
-			srx->transport_type = SOCK_DGRAM;
-			srx->transport_len = sizeof(srx->transport.sin);
-			srx->transport.sin.sin_family = AF_INET;
-			srx->transport.sin.sin_port = udp_hdr(skb)->source;
-			srx->transport.sin.sin_addr.s_addr = ip_hdr(skb)->saddr;
-		}
+		srx->transport_type = SOCK_DGRAM;
+		srx->transport_len = sizeof(srx->transport.sin);
+		srx->transport.sin.sin_family = AF_INET;
+		srx->transport.sin.sin_port = udp_hdr(skb)->source;
+		srx->transport.sin.sin_addr.s_addr = ip_hdr(skb)->saddr;
 		return 0;
 
 #ifdef CONFIG_AF_RXRPC_IPV6