From a8fc92778080c845eaadc369a0ecf5699a03bef0 Mon Sep 17 00:00:00 2001 From: Pavel Emelyanov Date: Thu, 1 Nov 2012 02:01:48 +0000 Subject: sk-filter: Add ability to get socket filter program (v2) The SO_ATTACH_FILTER option is set only. I propose to add the get ability by using SO_ATTACH_FILTER in getsockopt. To be less irritating to eyes the SO_GET_FILTER alias to it is declared. This ability is required by checkpoint-restore project to be able to save full state of a socket. There are two issues with getting filter back. First, kernel modifies the sock_filter->code on filter load, thus in order to return the filter element back to user we have to decode it into user-visible constants. Fortunately the modification in question is interconvertible. Second, the BPF_S_ALU_DIV_K code modifies the command argument k to speed up the run-time division by doing kernel_k = reciprocal(user_k). Bad news is that different user_k may result in same kernel_k, so we can't get the original user_k back. Good news is that we don't have to do it. What we need to is calculate a user2_k so, that reciprocal(user2_k) == reciprocal(user_k) == kernel_k i.e. if it's re-loaded back the compiled again value will be exactly the same as it was. That said, the user2_k can be calculated like this user2_k = reciprocal(kernel_k) with an exception, that if kernel_k == 0, then user2_k == 1. The optlen argument is treated like this -- when zero, kernel returns the amount of sock_fprog elements in filter, otherwise it should be large enough for the sock_fprog array. changes since v1: * Declared SO_GET_FILTER in all arch headers * Added decode of vlan-tag codes Signed-off-by: Pavel Emelyanov Signed-off-by: David S. Miller --- arch/alpha/include/asm/socket.h | 1 + arch/avr32/include/uapi/asm/socket.h | 1 + arch/cris/include/asm/socket.h | 1 + arch/frv/include/uapi/asm/socket.h | 1 + arch/h8300/include/asm/socket.h | 1 + arch/ia64/include/uapi/asm/socket.h | 1 + arch/m32r/include/asm/socket.h | 1 + arch/m68k/include/asm/socket.h | 1 + arch/mips/include/uapi/asm/socket.h | 1 + arch/mn10300/include/uapi/asm/socket.h | 1 + arch/parisc/include/asm/socket.h | 1 + arch/powerpc/include/uapi/asm/socket.h | 1 + arch/s390/include/uapi/asm/socket.h | 1 + arch/sparc/include/uapi/asm/socket.h | 1 + arch/xtensa/include/asm/socket.h | 1 + 15 files changed, 15 insertions(+) (limited to 'arch') diff --git a/arch/alpha/include/asm/socket.h b/arch/alpha/include/asm/socket.h index 7d2f75be932..0087d053b77 100644 --- a/arch/alpha/include/asm/socket.h +++ b/arch/alpha/include/asm/socket.h @@ -47,6 +47,7 @@ /* Socket filtering */ #define SO_ATTACH_FILTER 26 #define SO_DETACH_FILTER 27 +#define SO_GET_FILTER SO_ATTACH_FILTER #define SO_PEERNAME 28 #define SO_TIMESTAMP 29 diff --git a/arch/avr32/include/uapi/asm/socket.h b/arch/avr32/include/uapi/asm/socket.h index a473f8c6a9a..486df68abee 100644 --- a/arch/avr32/include/uapi/asm/socket.h +++ b/arch/avr32/include/uapi/asm/socket.h @@ -40,6 +40,7 @@ /* Socket filtering */ #define SO_ATTACH_FILTER 26 #define SO_DETACH_FILTER 27 +#define SO_GET_FILTER SO_ATTACH_FILTER #define SO_PEERNAME 28 #define SO_TIMESTAMP 29 diff --git a/arch/cris/include/asm/socket.h b/arch/cris/include/asm/socket.h index ae52825021a..b681b043f6c 100644 --- a/arch/cris/include/asm/socket.h +++ b/arch/cris/include/asm/socket.h @@ -42,6 +42,7 @@ /* Socket filtering */ #define SO_ATTACH_FILTER 26 #define SO_DETACH_FILTER 27 +#define SO_GET_FILTER SO_ATTACH_FILTER #define SO_PEERNAME 28 #define SO_TIMESTAMP 29 diff --git a/arch/frv/include/uapi/asm/socket.h b/arch/frv/include/uapi/asm/socket.h index a5b1d7dbb20..871f89b7fbd 100644 --- a/arch/frv/include/uapi/asm/socket.h +++ b/arch/frv/include/uapi/asm/socket.h @@ -40,6 +40,7 @@ /* Socket filtering */ #define SO_ATTACH_FILTER 26 #define SO_DETACH_FILTER 27 +#define SO_GET_FILTER SO_ATTACH_FILTER #define SO_PEERNAME 28 #define SO_TIMESTAMP 29 diff --git a/arch/h8300/include/asm/socket.h b/arch/h8300/include/asm/socket.h index ec4554e7b04..90a2e573c7e 100644 --- a/arch/h8300/include/asm/socket.h +++ b/arch/h8300/include/asm/socket.h @@ -40,6 +40,7 @@ /* Socket filtering */ #define SO_ATTACH_FILTER 26 #define SO_DETACH_FILTER 27 +#define SO_GET_FILTER SO_ATTACH_FILTER #define SO_PEERNAME 28 #define SO_TIMESTAMP 29 diff --git a/arch/ia64/include/uapi/asm/socket.h b/arch/ia64/include/uapi/asm/socket.h index 41fc28a4a18..23d6759bb57 100644 --- a/arch/ia64/include/uapi/asm/socket.h +++ b/arch/ia64/include/uapi/asm/socket.h @@ -49,6 +49,7 @@ /* Socket filtering */ #define SO_ATTACH_FILTER 26 #define SO_DETACH_FILTER 27 +#define SO_GET_FILTER SO_ATTACH_FILTER #define SO_PEERNAME 28 #define SO_TIMESTAMP 29 diff --git a/arch/m32r/include/asm/socket.h b/arch/m32r/include/asm/socket.h index a15f40b5278..5e7088a2672 100644 --- a/arch/m32r/include/asm/socket.h +++ b/arch/m32r/include/asm/socket.h @@ -40,6 +40,7 @@ /* Socket filtering */ #define SO_ATTACH_FILTER 26 #define SO_DETACH_FILTER 27 +#define SO_GET_FILTER SO_ATTACH_FILTER #define SO_PEERNAME 28 #define SO_TIMESTAMP 29 diff --git a/arch/m68k/include/asm/socket.h b/arch/m68k/include/asm/socket.h index d1be684edf9..285da3b6ad9 100644 --- a/arch/m68k/include/asm/socket.h +++ b/arch/m68k/include/asm/socket.h @@ -40,6 +40,7 @@ /* Socket filtering */ #define SO_ATTACH_FILTER 26 #define SO_DETACH_FILTER 27 +#define SO_GET_FILTER SO_ATTACH_FILTER #define SO_PEERNAME 28 #define SO_TIMESTAMP 29 diff --git a/arch/mips/include/uapi/asm/socket.h b/arch/mips/include/uapi/asm/socket.h index c5ed59549cb..17307ab9047 100644 --- a/arch/mips/include/uapi/asm/socket.h +++ b/arch/mips/include/uapi/asm/socket.h @@ -63,6 +63,7 @@ To add: #define SO_REUSEPORT 0x0200 /* Allow local address and port reuse. */ /* Socket filtering */ #define SO_ATTACH_FILTER 26 #define SO_DETACH_FILTER 27 +#define SO_GET_FILTER SO_ATTACH_FILTER #define SO_PEERNAME 28 #define SO_TIMESTAMP 29 diff --git a/arch/mn10300/include/uapi/asm/socket.h b/arch/mn10300/include/uapi/asm/socket.h index 820463a484b..af5366bbfe6 100644 --- a/arch/mn10300/include/uapi/asm/socket.h +++ b/arch/mn10300/include/uapi/asm/socket.h @@ -40,6 +40,7 @@ /* Socket filtering */ #define SO_ATTACH_FILTER 26 #define SO_DETACH_FILTER 27 +#define SO_GET_FILTER SO_ATTACH_FILTER #define SO_PEERNAME 28 #define SO_TIMESTAMP 29 diff --git a/arch/parisc/include/asm/socket.h b/arch/parisc/include/asm/socket.h index 1b52c2c31a7..d9ff4731253 100644 --- a/arch/parisc/include/asm/socket.h +++ b/arch/parisc/include/asm/socket.h @@ -48,6 +48,7 @@ /* Socket filtering */ #define SO_ATTACH_FILTER 0x401a #define SO_DETACH_FILTER 0x401b +#define SO_GET_FILTER SO_ATTACH_FILTER #define SO_ACCEPTCONN 0x401c diff --git a/arch/powerpc/include/uapi/asm/socket.h b/arch/powerpc/include/uapi/asm/socket.h index 3d5179bb122..eb0b1864d40 100644 --- a/arch/powerpc/include/uapi/asm/socket.h +++ b/arch/powerpc/include/uapi/asm/socket.h @@ -47,6 +47,7 @@ /* Socket filtering */ #define SO_ATTACH_FILTER 26 #define SO_DETACH_FILTER 27 +#define SO_GET_FILTER SO_ATTACH_FILTER #define SO_PEERNAME 28 #define SO_TIMESTAMP 29 diff --git a/arch/s390/include/uapi/asm/socket.h b/arch/s390/include/uapi/asm/socket.h index 69718cd6d63..436d07c23be 100644 --- a/arch/s390/include/uapi/asm/socket.h +++ b/arch/s390/include/uapi/asm/socket.h @@ -46,6 +46,7 @@ /* Socket filtering */ #define SO_ATTACH_FILTER 26 #define SO_DETACH_FILTER 27 +#define SO_GET_FILTER SO_ATTACH_FILTER #define SO_PEERNAME 28 #define SO_TIMESTAMP 29 diff --git a/arch/sparc/include/uapi/asm/socket.h b/arch/sparc/include/uapi/asm/socket.h index bea1568ae4a..c83a937ead0 100644 --- a/arch/sparc/include/uapi/asm/socket.h +++ b/arch/sparc/include/uapi/asm/socket.h @@ -41,6 +41,7 @@ #define SO_ATTACH_FILTER 0x001a #define SO_DETACH_FILTER 0x001b +#define SO_GET_FILTER SO_ATTACH_FILTER #define SO_PEERNAME 0x001c #define SO_TIMESTAMP 0x001d diff --git a/arch/xtensa/include/asm/socket.h b/arch/xtensa/include/asm/socket.h index e36c6818492..38079be1cf1 100644 --- a/arch/xtensa/include/asm/socket.h +++ b/arch/xtensa/include/asm/socket.h @@ -52,6 +52,7 @@ #define SO_ATTACH_FILTER 26 #define SO_DETACH_FILTER 27 +#define SO_GET_FILTER SO_ATTACH_FILTER #define SO_PEERNAME 28 #define SO_TIMESTAMP 29 -- cgit v1.2.3-70-g09d2