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From:   Bobby Eshleman <bobby.eshleman@bytedance.com>
Date:   Wed, 19 Jul 2023 00:50:08 +0000
Subject: [PATCH RFC net-next v5 04/14] af_vsock: generalize bind table
 functions
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Message-Id: <20230413-b4-vsock-dgram-v5-4-581bd37fdb26@bytedance.com>
References: <20230413-b4-vsock-dgram-v5-0-581bd37fdb26@bytedance.com>
In-Reply-To: <20230413-b4-vsock-dgram-v5-0-581bd37fdb26@bytedance.com>
To:     Stefan Hajnoczi <stefanha@redhat.com>,
        Stefano Garzarella <sgarzare@redhat.com>,
        "Michael S. Tsirkin" <mst@redhat.com>,
        Jason Wang <jasowang@redhat.com>,
        Xuan Zhuo <xuanzhuo@linux.alibaba.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        "K. Y. Srinivasan" <kys@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        Wei Liu <wei.liu@kernel.org>, Dexuan Cui <decui@microsoft.com>,
        Bryan Tan <bryantan@vmware.com>,
        Vishnu Dasa <vdasa@vmware.com>,
        VMware PV-Drivers Reviewers <pv-drivers@vmware.com>
Cc:     Dan Carpenter <dan.carpenter@linaro.org>,
        Simon Horman <simon.horman@corigine.com>,
        Krasnov Arseniy <oxffffaa@gmail.com>, kvm@vger.kernel.org,
        virtualization@lists.linux-foundation.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org,
        bpf@vger.kernel.org, Bobby Eshleman <bobby.eshleman@bytedance.com>
Precedence: bulk

This commit makes the bind table management functions in vsock usable
for different bind tables. Future work will introduce a new table for
datagrams to avoid address collisions, and these functions will be used
there.

Signed-off-by: Bobby Eshleman <bobby.eshleman@bytedance.com>
---
 net/vmw_vsock/af_vsock.c | 34 +++++++++++++++++++++++++++-------
 1 file changed, 27 insertions(+), 7 deletions(-)

diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index 26c97b33d55a..88100154156c 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -231,11 +231,12 @@ static void __vsock_remove_connected(struct vsock_sock *vsk)
 	sock_put(&vsk->sk);
 }
 
-static struct sock *__vsock_find_bound_socket(struct sockaddr_vm *addr)
+static struct sock *vsock_find_bound_socket_common(struct sockaddr_vm *addr,
+						   struct list_head *bind_table)
 {
 	struct vsock_sock *vsk;
 
-	list_for_each_entry(vsk, vsock_bound_sockets(addr), bound_table) {
+	list_for_each_entry(vsk, bind_table, bound_table) {
 		if (vsock_addr_equals_addr(addr, &vsk->local_addr))
 			return sk_vsock(vsk);
 
@@ -248,6 +249,11 @@ static struct sock *__vsock_find_bound_socket(struct sockaddr_vm *addr)
 	return NULL;
 }
 
+static struct sock *__vsock_find_bound_socket(struct sockaddr_vm *addr)
+{
+	return vsock_find_bound_socket_common(addr, vsock_bound_sockets(addr));
+}
+
 static struct sock *__vsock_find_connected_socket(struct sockaddr_vm *src,
 						  struct sockaddr_vm *dst)
 {
@@ -647,12 +653,18 @@ static void vsock_pending_work(struct work_struct *work)
 
 /**** SOCKET OPERATIONS ****/
 
-static int __vsock_bind_connectible(struct vsock_sock *vsk,
-				    struct sockaddr_vm *addr)
+static int vsock_bind_common(struct vsock_sock *vsk,
+			     struct sockaddr_vm *addr,
+			     struct list_head *bind_table,
+			     size_t table_size)
 {
 	static u32 port;
 	struct sockaddr_vm new_addr;
 
+	if (WARN_ONCE(table_size < VSOCK_HASH_SIZE,
+		      "table size too small, may cause overflow"))
+		return -EINVAL;
+
 	if (!port)
 		port = get_random_u32_above(LAST_RESERVED_PORT);
 
@@ -668,7 +680,8 @@ static int __vsock_bind_connectible(struct vsock_sock *vsk,
 
 			new_addr.svm_port = port++;
 
-			if (!__vsock_find_bound_socket(&new_addr)) {
+			if (!vsock_find_bound_socket_common(&new_addr,
+							    &bind_table[VSOCK_HASH(addr)])) {
 				found = true;
 				break;
 			}
@@ -685,7 +698,8 @@ static int __vsock_bind_connectible(struct vsock_sock *vsk,
 			return -EACCES;
 		}
 
-		if (__vsock_find_bound_socket(&new_addr))
+		if (vsock_find_bound_socket_common(&new_addr,
+						   &bind_table[VSOCK_HASH(addr)]))
 			return -EADDRINUSE;
 	}
 
@@ -697,11 +711,17 @@ static int __vsock_bind_connectible(struct vsock_sock *vsk,
 	 * by AF_UNIX.
 	 */
 	__vsock_remove_bound(vsk);
-	__vsock_insert_bound(vsock_bound_sockets(&vsk->local_addr), vsk);
+	__vsock_insert_bound(&bind_table[VSOCK_HASH(&vsk->local_addr)], vsk);
 
 	return 0;
 }
 
+static int __vsock_bind_connectible(struct vsock_sock *vsk,
+				    struct sockaddr_vm *addr)
+{
+	return vsock_bind_common(vsk, addr, vsock_bind_table, VSOCK_HASH_SIZE + 1);
+}
+
 static int __vsock_bind_dgram(struct vsock_sock *vsk,
 			      struct sockaddr_vm *addr)
 {

-- 
2.30.2