linux/arch/alpha/include/asm/socket.h
Pavel Emelyanov a8fc927780 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 <xemul@parallels.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-11-01 11:17:15 -04:00

88 lines
2.2 KiB
C

#ifndef _ASM_SOCKET_H
#define _ASM_SOCKET_H
#include <asm/sockios.h>
/* For setsockopt(2) */
/*
* Note: we only bother about making the SOL_SOCKET options
* same as OSF/1, as that's all that "normal" programs are
* likely to set. We don't necessarily want to be binary
* compatible with _everything_.
*/
#define SOL_SOCKET 0xffff
#define SO_DEBUG 0x0001
#define SO_REUSEADDR 0x0004
#define SO_KEEPALIVE 0x0008
#define SO_DONTROUTE 0x0010
#define SO_BROADCAST 0x0020
#define SO_LINGER 0x0080
#define SO_OOBINLINE 0x0100
/* To add :#define SO_REUSEPORT 0x0200 */
#define SO_TYPE 0x1008
#define SO_ERROR 0x1007
#define SO_SNDBUF 0x1001
#define SO_RCVBUF 0x1002
#define SO_SNDBUFFORCE 0x100a
#define SO_RCVBUFFORCE 0x100b
#define SO_RCVLOWAT 0x1010
#define SO_SNDLOWAT 0x1011
#define SO_RCVTIMEO 0x1012
#define SO_SNDTIMEO 0x1013
#define SO_ACCEPTCONN 0x1014
#define SO_PROTOCOL 0x1028
#define SO_DOMAIN 0x1029
/* linux-specific, might as well be the same as on i386 */
#define SO_NO_CHECK 11
#define SO_PRIORITY 12
#define SO_BSDCOMPAT 14
#define SO_PASSCRED 17
#define SO_PEERCRED 18
#define SO_BINDTODEVICE 25
/* 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
#define SCM_TIMESTAMP SO_TIMESTAMP
#define SO_PEERSEC 30
#define SO_PASSSEC 34
#define SO_TIMESTAMPNS 35
#define SCM_TIMESTAMPNS SO_TIMESTAMPNS
/* Security levels - as per NRL IPv6 - don't actually do anything */
#define SO_SECURITY_AUTHENTICATION 19
#define SO_SECURITY_ENCRYPTION_TRANSPORT 20
#define SO_SECURITY_ENCRYPTION_NETWORK 21
#define SO_MARK 36
#define SO_TIMESTAMPING 37
#define SCM_TIMESTAMPING SO_TIMESTAMPING
#define SO_RXQ_OVFL 40
#define SO_WIFI_STATUS 41
#define SCM_WIFI_STATUS SO_WIFI_STATUS
#define SO_PEEK_OFF 42
/* Instruct lower device to use last 4-bytes of skb data as FCS */
#define SO_NOFCS 43
#ifdef __KERNEL__
/* O_NONBLOCK clashes with the bits used for socket types. Therefore we
* have to define SOCK_NONBLOCK to a different value here.
*/
#define SOCK_NONBLOCK 0x40000000
#endif /* __KERNEL__ */
#endif /* _ASM_SOCKET_H */