From ea02f9411d9faa3553ed09ce0ec9f00ceae9885e Mon Sep 17 00:00:00 2001 From: Michal Sekletar Date: Fri, 17 Jan 2014 17:09:45 +0100 Subject: [PATCH] net: introduce SO_BPF_EXTENSIONS For user space packet capturing libraries such as libpcap, there's currently only one way to check which BPF extensions are supported by the kernel, that is, commit aa1113d9f85d ("net: filter: return -EINVAL if BPF_S_ANC* operation is not supported"). For querying all extensions at once this might be rather inconvenient. Therefore, this patch introduces a new option which can be used as an argument for getsockopt(), and allows one to obtain information about which BPF extensions are supported by the current kernel. As David Miller suggests, we do not need to define any bits right now and status quo can just return 0 in order to state that this versions supports SKF_AD_PROTOCOL up to SKF_AD_PAY_OFFSET. Later additions to BPF extensions need to add their bits to the bpf_tell_extensions() function, as documented in the comment. Signed-off-by: Michal Sekletar Cc: David Miller Reviewed-by: Daniel Borkmann Signed-off-by: David S. Miller --- arch/alpha/include/uapi/asm/socket.h | 2 ++ arch/avr32/include/uapi/asm/socket.h | 2 ++ arch/cris/include/uapi/asm/socket.h | 2 ++ arch/frv/include/uapi/asm/socket.h | 2 ++ arch/ia64/include/uapi/asm/socket.h | 2 ++ arch/m32r/include/uapi/asm/socket.h | 2 ++ arch/mips/include/uapi/asm/socket.h | 2 ++ arch/mn10300/include/uapi/asm/socket.h | 2 ++ arch/parisc/include/uapi/asm/socket.h | 2 ++ arch/powerpc/include/uapi/asm/socket.h | 2 ++ arch/s390/include/uapi/asm/socket.h | 2 ++ arch/sparc/include/uapi/asm/socket.h | 2 ++ arch/xtensa/include/uapi/asm/socket.h | 2 ++ include/linux/filter.h | 11 +++++++++++ include/uapi/asm-generic/socket.h | 2 ++ net/core/sock.c | 4 ++++ 16 files changed, 43 insertions(+) diff --git a/arch/alpha/include/uapi/asm/socket.h b/arch/alpha/include/uapi/asm/socket.h index e3a1491d5073a..3de1394bcab82 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 cbf902e4cd9e9..6e6cd159924b1 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 13829aaaeec56..ed94e5ed0a238 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 5d4299762426b..ca2c6e6f31c68 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 c25302fb48d95..a1b49bac79519 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 52966650114f3..6c9a24b3aefa3 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 0df9787cd84d9..a14baa218c76f 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 71dedcae55a69..6aa3ce1854aa9 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 70b3674dac4e3..fe35ceacf0e72 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 fa698324a1fd1..a9c3e2e18c054 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 c286c2e868f03..e031332096d7c 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 0f21e9a5ca188..54d9608681b69 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 7db5c22faa68a..39acec0cf0b1d 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 ff4e40cd45b1d..1a95a2dcf113a 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 38f14d0264c3a..ea0796bdcf884 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 b3f7ee3008a0d..0c127dcdf6a8b 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; -- 2.39.5