BACKPORT: net: initial AF_XDP skeleton

Buildable skeleton of AF_XDP without any functionality. Just what it
takes to register a new address family.

Change-Id: I2116ce900e3ac94ab7329ec9578a3f8eff9d750d
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sorayukii <sorayukii69@gmail.com>

MAINTAINERS

@@ -13260,6 +13260,14 @@ T:	git git://linuxtv.org/media_tree.git
 S:	Maintained
 F:	drivers/media/tuners/tuner-xc2028.*
 
+XDP SOCKETS (AF_XDP)
+M:	Björn Töpel <bjorn.topel@intel.com>
+M:	Magnus Karlsson <magnus.karlsson@intel.com>
+L:	netdev@vger.kernel.org
+S:	Maintained
+F:	kernel/bpf/xskmap.c
+F:	net/xdp/
+
 XEN HYPERVISOR INTERFACE
 M:	Boris Ostrovsky <boris.ostrovsky@oracle.com>
 M:	David Vrabel <david.vrabel@citrix.com>

include/linux/socket.h

@@ -202,8 +202,8 @@ struct ucred {
 #define AF_VSOCK	40	/* vSockets			*/
 #define AF_KCM		41	/* Kernel Connection Multiplexor*/
 #define AF_QIPCRTR	42	/* Qualcomm IPC Router          */
-
-#define AF_MAX		43	/* For now.. */
+#define AF_XDP		43	/* XDP sockets			*/
+#define AF_MAX		44	/* For now.. */
 
 /* Protocol families, same as address families. */
 #define PF_UNSPEC	AF_UNSPEC
@@ -251,6 +251,7 @@ struct ucred {
 #define PF_VSOCK	AF_VSOCK
 #define PF_KCM		AF_KCM
 #define PF_QIPCRTR	AF_QIPCRTR
+#define PF_XDP		AF_XDP
 #define PF_MAX		AF_MAX
 
 /* Maximum queue length specifiable by listen.  */
@@ -332,6 +333,7 @@ struct ucred {
 #define SOL_NFC		280
 #define SOL_KCM		281
 #define SOL_TLS		282
+#define SOL_XDP		283
 
 /* IPX options */
 #define IPX_TYPE	1

net/Kconfig

@@ -58,6 +58,7 @@ source "net/unix/Kconfig"
 source "net/tls/Kconfig"
 source "net/xfrm/Kconfig"
 source "net/iucv/Kconfig"
+source "net/xdp/Kconfig"
 
 config INET
 	bool "TCP/IP networking"

net/core/sock.c

@@ -224,7 +224,7 @@ static struct lock_class_key af_family_kern_slock_keys[AF_MAX];
   x "AF_RXRPC" ,	x "AF_ISDN"     ,	x "AF_PHONET"   , \
   x "AF_IEEE802154",	x "AF_CAIF"	,	x "AF_ALG"      , \
   x "AF_NFC"   ,	x "AF_VSOCK"    ,	x "AF_KCM"      , \
-  x "AF_QIPCRTR",	x "AF_MAX"
+  x "AF_QIPCRTR",	x "AF_XDP"	,	x "AF_MAX"
 
 static const char *const af_family_key_strings[AF_MAX+1] = {
 	_sock_locks("sk_lock-")

net/xdp/Kconfig

@@ -0,0 +1,7 @@
+config XDP_SOCKETS
+	bool "XDP sockets"
+	depends on BPF_SYSCALL
+	default n
+	help
+	  XDP sockets allows a channel between XDP programs and
+	  userspace applications.

security/selinux/include/classmap.h

@@ -168,5 +168,7 @@ struct security_class_mapping secclass_map[] = {
 	  { COMMON_CAP2_PERMS, NULL } },
 	{ "bpf",
 	  {"map_create", "map_read", "map_write", "prog_load", "prog_run"} },
+	{ "xdp_socket",
+	  { COMMON_SOCK_PERMS, NULL } },
 	{ NULL }
   };