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Commit b21c8f83 authored by Dominik Brodowski's avatar Dominik Brodowski
Browse files

net: socket: add __sys_getpeername() helper; remove in-kernel call to syscall 

Using the net-internal helper __sys_getpeername() allows us to avoid the
internal calls to the sys_getpeername() syscall.

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net



Cc: David S. Miller <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Signed-off-by: default avatarDominik Brodowski <linux@dominikbrodowski.net>
parent 8882a107

include/linux/socket.h

+2 −0
Original line number Diff line number Diff line
@@ -370,5 +370,7 @@ extern int __sys_connect(int fd, struct sockaddr __user *uservaddr, 
extern int __sys_listen(int fd, int backlog);

extern int __sys_getsockname(int fd, struct sockaddr __user *usockaddr,

			     int __user *usockaddr_len);

extern int __sys_getpeername(int fd, struct sockaddr __user *usockaddr,

			     int __user *usockaddr_len);



#endif /* _LINUX_SOCKET_H */

net/compat.c

+1 −1
Original line number Diff line number Diff line
@@ -829,7 +829,7 @@ COMPAT_SYSCALL_DEFINE2(socketcall, int, call, u32 __user *, args) 
		ret = __sys_getsockname(a0, compat_ptr(a1), compat_ptr(a[2]));

		break;

	case SYS_GETPEERNAME:

		ret = sys_getpeername(a0, compat_ptr(a1), compat_ptr(a[2]));

		ret = __sys_getpeername(a0, compat_ptr(a1), compat_ptr(a[2]));

		break;

	case SYS_SOCKETPAIR:

		ret = sys_socketpair(a0, a1, a[2], compat_ptr(a[3]));

net/socket.c

+10 −4
Original line number Diff line number Diff line
@@ -1712,8 +1712,8 @@ SYSCALL_DEFINE3(getsockname, int, fd, struct sockaddr __user *, usockaddr, 
 *	name to user space.

 */



SYSCALL_DEFINE3(getpeername, int, fd, struct sockaddr __user *, usockaddr,

		int __user *, usockaddr_len)

int __sys_getpeername(int fd, struct sockaddr __user *usockaddr,

		      int __user *usockaddr_len)

{

	struct socket *sock;

	struct sockaddr_storage address;
@@ -1738,6 +1738,12 @@ SYSCALL_DEFINE3(getpeername, int, fd, struct sockaddr __user *, usockaddr, 
	return err;

}



SYSCALL_DEFINE3(getpeername, int, fd, struct sockaddr __user *, usockaddr,

		int __user *, usockaddr_len)

{

	return __sys_getpeername(fd, usockaddr, usockaddr_len);

}



/*

 *	Send a datagram to a given address. We move the address into kernel

 *	space and check the user space data area is readable before invoking
@@ -2511,7 +2517,7 @@ SYSCALL_DEFINE2(socketcall, int, call, unsigned long __user *, args) 
		break;

	case SYS_GETPEERNAME:

		err =

		    sys_getpeername(a0, (struct sockaddr __user *)a1,

		    __sys_getpeername(a0, (struct sockaddr __user *)a1,

				      (int __user *)a[2]);

		break;

	case SYS_SOCKETPAIR: