16 files changed, 43 insertions, 0 deletions

diff --git a/arch/alpha/include/uapi/asm/socket.h b/arch/alpha/include/uapi/asm/socket.h
index e3a1491d5073..3de1394bcab8 100644
--- a/arch/alpha/include/uapi/asm/socket.h
+++ b/arch/alpha/include/uapi/asm/socket.h
@@ -85,4 +85,6 @@
 
 #define SO_MAX_PACING_RATE      47
 
+#define SO_BPF_EXTENSIONS       48
+
 #endif /* _UAPI_ASM_SOCKET_H */
diff --git a/arch/avr32/include/uapi/asm/socket.h b/arch/avr32/include/uapi/asm/socket.h
index cbf902e4cd9e..6e6cd159924b 100644
--- a/arch/avr32/include/uapi/asm/socket.h
+++ b/arch/avr32/include/uapi/asm/socket.h
@@ -78,4 +78,6 @@
 
 #define SO_MAX_PACING_RATE      47
 
+#define SO_BPF_EXTENSIONS       48
+
 #endif /* _UAPI__ASM_AVR32_SOCKET_H */
diff --git a/arch/cris/include/uapi/asm/socket.h b/arch/cris/include/uapi/asm/socket.h
index 13829aaaeec5..ed94e5ed0a23 100644
--- a/arch/cris/include/uapi/asm/socket.h
+++ b/arch/cris/include/uapi/asm/socket.h
@@ -80,6 +80,8 @@
 
 #define SO_MAX_PACING_RATE      47
 
+#define SO_BPF_EXTENSIONS       48
+
 #endif /* _ASM_SOCKET_H */
 
 
diff --git a/arch/frv/include/uapi/asm/socket.h b/arch/frv/include/uapi/asm/socket.h
index 5d4299762426..ca2c6e6f31c6 100644
--- a/arch/frv/include/uapi/asm/socket.h
+++ b/arch/frv/include/uapi/asm/socket.h
@@ -78,5 +78,7 @@
 
 #define SO_MAX_PACING_RATE      47
 
+#define SO_BPF_EXTENSIONS       48
+
 #endif /* _ASM_SOCKET_H */
 
diff --git a/arch/ia64/include/uapi/asm/socket.h b/arch/ia64/include/uapi/asm/socket.h
index c25302fb48d9..a1b49bac7951 100644
--- a/arch/ia64/include/uapi/asm/socket.h
+++ b/arch/ia64/include/uapi/asm/socket.h
@@ -87,4 +87,6 @@
 
 #define SO_MAX_PACING_RATE      47
 
+#define SO_BPF_EXTENSIONS       48
+
 #endif /* _ASM_IA64_SOCKET_H */
diff --git a/arch/m32r/include/uapi/asm/socket.h b/arch/m32r/include/uapi/asm/socket.h
index 52966650114f..6c9a24b3aefa 100644
--- a/arch/m32r/include/uapi/asm/socket.h
+++ b/arch/m32r/include/uapi/asm/socket.h
@@ -78,4 +78,6 @@
 
 #define SO_MAX_PACING_RATE      47
 
+#define SO_BPF_EXTENSIONS       48
+
 #endif /* _ASM_M32R_SOCKET_H */
diff --git a/arch/mips/include/uapi/asm/socket.h b/arch/mips/include/uapi/asm/socket.h
index 0df9787cd84d..a14baa218c76 100644
--- a/arch/mips/include/uapi/asm/socket.h
+++ b/arch/mips/include/uapi/asm/socket.h
@@ -96,4 +96,6 @@
 
 #define SO_MAX_PACING_RATE      47
 
+#define SO_BPF_EXTENSIONS       48
+
 #endif /* _UAPI_ASM_SOCKET_H */
diff --git a/arch/mn10300/include/uapi/asm/socket.h b/arch/mn10300/include/uapi/asm/socket.h
index 71dedcae55a6..6aa3ce1854aa 100644
--- a/arch/mn10300/include/uapi/asm/socket.h
+++ b/arch/mn10300/include/uapi/asm/socket.h
@@ -78,4 +78,6 @@
 
 #define SO_MAX_PACING_RATE      47
 
+#define SO_BPF_EXTENSIONS       48
+
 #endif /* _ASM_SOCKET_H */
diff --git a/arch/parisc/include/uapi/asm/socket.h b/arch/parisc/include/uapi/asm/socket.h
index 70b3674dac4e..fe35ceacf0e7 100644
--- a/arch/parisc/include/uapi/asm/socket.h
+++ b/arch/parisc/include/uapi/asm/socket.h
@@ -77,4 +77,6 @@
 
 #define SO_MAX_PACING_RATE      0x4028
 
+#define SO_BPF_EXTENSIONS       0x4029
+
 #endif /* _UAPI_ASM_SOCKET_H */
diff --git a/arch/powerpc/include/uapi/asm/socket.h b/arch/powerpc/include/uapi/asm/socket.h
index fa698324a1fd..a9c3e2e18c05 100644
--- a/arch/powerpc/include/uapi/asm/socket.h
+++ b/arch/powerpc/include/uapi/asm/socket.h
@@ -85,4 +85,6 @@
 
 #define SO_MAX_PACING_RATE      47
 
+#define SO_BPF_EXTENSIONS       48
+
 #endif  /* _ASM_POWERPC_SOCKET_H */
diff --git a/arch/s390/include/uapi/asm/socket.h b/arch/s390/include/uapi/asm/socket.h
index c286c2e868f0..e031332096d7 100644
--- a/arch/s390/include/uapi/asm/socket.h
+++ b/arch/s390/include/uapi/asm/socket.h
@@ -84,4 +84,6 @@
 
 #define SO_MAX_PACING_RATE      47
 
+#define SO_BPF_EXTENSIONS       48
+
 #endif /* _ASM_SOCKET_H */
diff --git a/arch/sparc/include/uapi/asm/socket.h b/arch/sparc/include/uapi/asm/socket.h
index 0f21e9a5ca18..54d9608681b6 100644
--- a/arch/sparc/include/uapi/asm/socket.h
+++ b/arch/sparc/include/uapi/asm/socket.h
@@ -74,6 +74,8 @@
 
 #define SO_MAX_PACING_RATE      0x0031
 
+#define SO_BPF_EXTENSIONS       0x0032
+
 /* Security levels - as per NRL IPv6 - don't actually do anything */
 #define SO_SECURITY_AUTHENTICATION              0x5001
 #define SO_SECURITY_ENCRYPTION_TRANSPORT        0x5002
diff --git a/arch/xtensa/include/uapi/asm/socket.h b/arch/xtensa/include/uapi/asm/socket.h
index 7db5c22faa68..39acec0cf0b1 100644
--- a/arch/xtensa/include/uapi/asm/socket.h
+++ b/arch/xtensa/include/uapi/asm/socket.h
@@ -89,4 +89,6 @@
 
 #define SO_MAX_PACING_RATE      47
 
+#define SO_BPF_EXTENSIONS       48
+
 #endif  /* _XTENSA_SOCKET_H */
diff --git a/include/linux/filter.h b/include/linux/filter.h
index ff4e40cd45b1..1a95a2dcf113 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -83,6 +83,17 @@ static inline void bpf_jit_free(struct sk_filter *fp)
 #define SK_RUN_FILTER(FILTER, SKB) sk_run_filter(SKB, FILTER->insns)
 #endif
 
+static inline int bpf_tell_extensions(void)
+{
+        /* When adding new BPF extension it is necessary to enumerate
+         * it here, so userspace software which wants to know what is
+         * supported can do so by inspecting return value of this
+         * function
+         */
+
+        return 0;
+}
+
 enum {
         BPF_S_RET_K = 1,
         BPF_S_RET_A,
diff --git a/include/uapi/asm-generic/socket.h b/include/uapi/asm-generic/socket.h
index 38f14d0264c3..ea0796bdcf88 100644
--- a/include/uapi/asm-generic/socket.h
+++ b/include/uapi/asm-generic/socket.h
@@ -80,4 +80,6 @@
 
 #define SO_MAX_PACING_RATE      47
 
+#define SO_BPF_EXTENSIONS       48
+
 #endif /* __ASM_GENERIC_SOCKET_H */
diff --git a/net/core/sock.c b/net/core/sock.c
index b3f7ee3008a0..0c127dcdf6a8 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1167,6 +1167,10 @@ int sock_getsockopt(struct socket *sock, int level, int optname,
                 v.val = sock_flag(sk, SOCK_FILTER_LOCKED);
                 break;
 
+        case SO_BPF_EXTENSIONS:
+                v.val = bpf_tell_extensions();
+                break;
+
         case SO_SELECT_ERR_QUEUE:
                 v.val = sock_flag(sk, SOCK_SELECT_ERR_QUEUE);
                 break;