net: socket: Added notifier chains for socket administrative functions

Allows other areas in the kernel to register notifier callbacks which
get invoked whenever something performs an administrative action on a
socket. This patch adds hooks in socket(), bind(), listen(), accept(),
shutdown().

CRs-Fixed:  626021
Change-Id: I4ae99cb2206d7c4eddba69757335c18d10143045
Signed-off-by: Harout Hedeshian <harouth@codeaurora.org>
[subashab@codeaurora.org: resolve trivial merge conflicts]
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>

1 files changed, 35 insertions, 1 deletions

diff --git a/net/socket.c b/net/socket.c
index d730ef9dfbf0..7a6b5f2e4eba 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -115,6 +115,9 @@ unsigned int sysctl_net_busy_poll __read_mostly;
 
 static ssize_t sock_read_iter(struct kiocb *iocb, struct iov_iter *to);
 static ssize_t sock_write_iter(struct kiocb *iocb, struct iov_iter *from);
+
+static BLOCKING_NOTIFIER_HEAD(sockev_notifier_list);
+
 static int sock_mmap(struct file *file, struct vm_area_struct *vma);
 
 static int sock_close(struct inode *inode, struct file *file);
@@ -169,6 +172,14 @@ static const struct net_proto_family __rcu *net_families[NPROTO] __read_mostly;
 static DEFINE_PER_CPU(int, sockets_in_use);
 
 /*
+ * Socket Event framework helpers
+ */
+static void sockev_notify(unsigned long event, struct socket *sk)
+{
+	blocking_notifier_call_chain(&sockev_notifier_list, event, sk);
+}
+
+/**
  * Support routines.
  * Move socket addresses back and forth across the kernel/user
  * divide and look after the messy bits.
@@ -1234,6 +1245,9 @@ SYSCALL_DEFINE3(socket, int, family, int, type, int, protocol)
 	if (retval < 0)
 		goto out;
 
+	if (retval == 0)
+		sockev_notify(SOCKEV_SOCKET, sock);
+
 	retval = sock_map_fd(sock, flags & (O_CLOEXEC | O_NONBLOCK));
 	if (retval < 0)
 		goto out_release;
@@ -1379,6 +1393,8 @@ SYSCALL_DEFINE3(bind, int, fd, struct sockaddr __user *, umyaddr, int, addrlen)
 						      &address, addrlen);
 		}
 		fput_light(sock->file, fput_needed);
+		if (!err)
+			sockev_notify(SOCKEV_BIND, sock);
 	}
 	return err;
 }
@@ -1406,6 +1422,8 @@ SYSCALL_DEFINE2(listen, int, fd, int, backlog)
 			err = sock->ops->listen(sock, backlog);
 
 		fput_light(sock->file, fput_needed);
+		if (!err)
+			sockev_notify(SOCKEV_LISTEN, sock);
 	}
 	return err;
 }
@@ -1492,7 +1510,8 @@ SYSCALL_DEFINE4(accept4, int, fd, struct sockaddr __user *, upeer_sockaddr,
 
 	fd_install(newfd, newfile);
 	err = newfd;
-
+	if (!err)
+		sockev_notify(SOCKEV_ACCEPT, sock);
 out_put:
 	fput_light(sock->file, fput_needed);
 out:
@@ -1542,6 +1561,8 @@ SYSCALL_DEFINE3(connect, int, fd, struct sockaddr __user *, uservaddr,
 
 	err = sock->ops->connect(sock, (struct sockaddr *)&address, addrlen,
 				 sock->file->f_flags);
+	if (!err)
+		sockev_notify(SOCKEV_CONNECT, sock);
 out_put:
 	fput_light(sock->file, fput_needed);
 out:
@@ -1799,6 +1820,7 @@ SYSCALL_DEFINE2(shutdown, int, fd, int, how)
 
 	sock = sockfd_lookup_light(fd, &err, &fput_needed);
 	if (sock != NULL) {
+		sockev_notify(SOCKEV_SHUTDOWN, sock);
 		err = security_socket_shutdown(sock, how);
 		if (!err)
 			err = sock->ops->shutdown(sock, how);
@@ -3294,3 +3316,15 @@ int kernel_sock_shutdown(struct socket *sock, enum sock_shutdown_cmd how)
 	return sock->ops->shutdown(sock, how);
 }
 EXPORT_SYMBOL(kernel_sock_shutdown);
+
+int sockev_register_notify(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_register(&sockev_notifier_list, nb);
+}
+EXPORT_SYMBOL(sockev_register_notify);
+
+int sockev_unregister_notify(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_unregister(&sockev_notifier_list, nb);
+}
+EXPORT_SYMBOL(sockev_unregister_notify);