rxrpc: Move peer lookup from call-accept to new-incoming-conn

Move the lookup of a peer from a call that's being accepted into the
function that creates a new incoming connection. This will allow us to
avoid incrementing the peer's usage count in some cases in future.

Note that I haven't bother to integrate rxrpc_get_addr_from_skb() with
rxrpc_extract_addr_from_skb() as I'm going to delete the former in the very
near future.

Signed-off-by: David Howells <[e-mail]>

net/rxrpc/ar-internal.h

···
  * conn_service.c
  */
 struct rxrpc_connection *rxrpc_incoming_connection(struct rxrpc_local *,
-						   struct rxrpc_peer *,
+						   struct sockaddr_rxrpc *,
 						   struct sk_buff *);
 
 /*
···
  */
 void rxrpc_get_addr_from_skb(struct rxrpc_local *, const struct sk_buff *,
 			     struct sockaddr_rxrpc *);
+int rxrpc_extract_addr_from_skb(struct sockaddr_rxrpc *, struct sk_buff *);
 
 /*
  * debug tracing

net/rxrpc/call_accept.c

···
 {
 	struct rxrpc_connection *conn;
 	struct rxrpc_skb_priv *sp, *nsp;
-	struct rxrpc_peer *peer;
 	struct rxrpc_call *call;
 	struct sk_buff *notification;
 	int ret;
···
 	rxrpc_new_skb(notification);
 	notification->mark = RXRPC_SKB_MARK_NEW_CALL;
 
-	peer = rxrpc_lookup_peer(local, srx, GFP_NOIO);
-	if (!peer) {
-		_debug("no peer");
-		ret = -EBUSY;
-		goto error;
-	}
-
-	conn = rxrpc_incoming_connection(local, peer, skb);
-	rxrpc_put_peer(peer);
+	conn = rxrpc_incoming_connection(local, srx, skb);
 	if (IS_ERR(conn)) {
 		_debug("no conn");
 		ret = PTR_ERR(conn);
···
 	whdr._rsvd	= 0;
 	whdr.serviceId	= htons(sp->hdr.serviceId);
 
-	/* determine the remote address */
-	memset(&srx, 0, sizeof(srx));
-	srx.srx_family = AF_RXRPC;
-	srx.transport.family = local->srx.transport.family;
-	srx.transport_type = local->srx.transport_type;
-	switch (srx.transport.family) {
-	case AF_INET:
-		srx.transport_len = sizeof(struct sockaddr_in);
-		srx.transport.sin.sin_port = udp_hdr(skb)->source;
-		srx.transport.sin.sin_addr.s_addr = ip_hdr(skb)->saddr;
-		break;
-	default:
-		goto busy;
-	}
+	if (rxrpc_extract_addr_from_skb(&srx, skb) < 0)
+		goto drop;
 
 	/* get the socket providing the service */
 	read_lock_bh(&local->services_lock);
···
 	read_unlock_bh(&local->services_lock);
 busy:
 	rxrpc_busy(local, &srx, &whdr);
+	rxrpc_free_skb(skb);
+	return;
+
+drop:
 	rxrpc_free_skb(skb);
 	return;
 

net/rxrpc/conn_service.c

···
  * get a record of an incoming connection
  */
 struct rxrpc_connection *rxrpc_incoming_connection(struct rxrpc_local *local,
-						   struct rxrpc_peer *peer,
+						   struct sockaddr_rxrpc *srx,
 						   struct sk_buff *skb)
 {
 	struct rxrpc_connection *conn, *candidate = NULL;
 	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+	struct rxrpc_peer *peer;
 	struct rb_node *p, **pp;
 	const char *new = "old";
 	u32 epoch, cid;
 
 	_enter("");
+
+	peer = rxrpc_lookup_peer(local, srx, GFP_NOIO);
+	if (!peer) {
+		_debug("no peer");
+		return ERR_PTR(-EBUSY);
+	}
 
 	ASSERT(sp->hdr.flags & RXRPC_CLIENT_INITIATED);
 
···
 	 * redo the search */
 	candidate = rxrpc_alloc_connection(GFP_NOIO);
 	if (!candidate) {
+		rxrpc_put_peer(peer);
 		_leave(" = -ENOMEM");
 		return ERR_PTR(-ENOMEM);
 	}
···
 success:
 	_net("CONNECTION %s %d {%x}", new, conn->debug_id, conn->proto.cid);
 
+	rxrpc_put_peer(peer);
 	_leave(" = %p {u=%d}", conn, atomic_read(&conn->usage));
 	return conn;
 

net/rxrpc/utils.c

···
  */
 
 #include <linux/ip.h>
+#include <linux/ipv6.h>
 #include <linux/udp.h>
 #include "ar-internal.h"
 
···
 
 	default:
 		BUG();
+	}
+}
+
+/*
+ * Fill out a peer address from a socket buffer containing a packet.
+ */
+int rxrpc_extract_addr_from_skb(struct sockaddr_rxrpc *srx, struct sk_buff *skb)
+{
+	memset(srx, 0, sizeof(*srx));
+
+	switch (ntohs(skb->protocol)) {
+	case ETH_P_IP:
+		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;
+
+	case ETH_P_IPV6:
+		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 = ipv6_hdr(skb)->saddr;
+		return 0;
+
+	default:
+		pr_warn_ratelimited("AF_RXRPC: Unknown eth protocol %u\n",
+				    ntohs(skb->protocol));
+		return -EAFNOSUPPORT;
 	}
 }