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: 7b674e3 ("rxrpc: Fix IPv6 support")
Signed-off-by: David Howells <dhowells@redhat.com>

fs/afs/addr_list.c

@@ -232,17 +232,17 @@ struct afs_addr_list *afs_dns_query(struct afs_cell *cell, time64_t *_expiry)
  */
 void afs_merge_fs_addr4(struct afs_addr_list *alist, __be32 xdr, u16 port)
 {
-	struct sockaddr_in6 *p;
+	struct sockaddr_rxrpc *srx;
 	u32 addr = ntohl(xdr);
 	int i;
 
 	if (alist->nr_addrs >= alist->max_addrs)
 		return;
 
 	for (i = 0; i < alist->nr_ipv4; i++) {
-		struct sockaddr_in6 *a = &alist->addrs[i].transport.sin6;
-		u32 a_addr = ntohl(a->sin6_addr.s6_addr32[3]);
-		u16 a_port = ntohs(a->sin6_port);
+		struct sockaddr_in *a = &alist->addrs[i].transport.sin;
+		u32 a_addr = ntohl(a->sin_addr.s_addr);
+		u16 a_port = ntohs(a->sin_port);
 
 		if (addr == a_addr && port == a_port)
 			return;
@@ -257,12 +257,11 @@ void afs_merge_fs_addr4(struct afs_addr_list *alist, __be32 xdr, u16 port)
 			alist->addrs + i,
 			sizeof(alist->addrs[0]) * (alist->nr_addrs - i));
 
-	p = &alist->addrs[i].transport.sin6;
-	p->sin6_port		  = htons(port);
-	p->sin6_addr.s6_addr32[0] = 0;
-	p->sin6_addr.s6_addr32[1] = 0;
-	p->sin6_addr.s6_addr32[2] = htonl(0xffff);
-	p->sin6_addr.s6_addr32[3] = xdr;
+	srx = &alist->addrs[i];
+	srx->transport_len = sizeof(srx->transport.sin);
+	srx->transport.sin.sin_family = AF_INET;
+	srx->transport.sin.sin_port = htons(port);
+	srx->transport.sin.sin_addr.s_addr = xdr;
 	alist->nr_ipv4++;
 	alist->nr_addrs++;
 }
@@ -272,7 +271,7 @@ void afs_merge_fs_addr4(struct afs_addr_list *alist, __be32 xdr, u16 port)
  */
 void afs_merge_fs_addr6(struct afs_addr_list *alist, __be32 *xdr, u16 port)
 {
-	struct sockaddr_in6 *p;
+	struct sockaddr_rxrpc *srx;
 	int i, diff;
 
 	if (alist->nr_addrs >= alist->max_addrs)
@@ -296,9 +295,11 @@ void afs_merge_fs_addr6(struct afs_addr_list *alist, __be32 *xdr, u16 port)
 			alist->addrs + i,
 			sizeof(alist->addrs[0]) * (alist->nr_addrs - i));
 
-	p = &alist->addrs[i].transport.sin6;
-	p->sin6_port = htons(port);
-	memcpy(&p->sin6_addr, xdr, 16);
+	srx = &alist->addrs[i];
+	srx->transport_len = sizeof(srx->transport.sin6);
+	srx->transport.sin6.sin6_family = AF_INET6;
+	srx->transport.sin6.sin6_port = htons(port);
+	memcpy(&srx->transport.sin6.sin6_addr, xdr, 16);
 	alist->nr_addrs++;
 }
 

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) {

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);

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;

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