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filter: add XOR instruction for use with X/K

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SKF_AD_ALU_XOR_X has been added a while ago, but as an 'ancillary'
operation that is invoked through a negative offset in K within BPF
load operations. Since BPF_MOD has recently been added, BPF_XOR should
also be part of the common ALU operations. Removing SKF_AD_ALU_XOR_X
might not be an option since this is exposed to user space.

Signed-off-by: Daniel Borkmann <daniel.borkmann@tik.ee.ethz.ch>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Daniel Borkmann 2012-09-24 02:23:59 +00:00 committed by David S. Miller
parent 718cffc4ac
commit 9e49e88958
2 changed files with 12 additions and 3 deletions
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3
include/linux/filter.h
View File

@ -75,6 +75,7 @@ struct sock_fprog { /* Required for SO_ATTACH_FILTER. */
#define BPF_RSH 0x70
#define BPF_NEG 0x80
#define BPF_MOD 0x90
#define BPF_XOR 0xa0
#define BPF_JA 0x00
#define BPF_JEQ 0x10
@ -204,6 +205,8 @@ enum {
BPF_S_ALU_AND_X,
BPF_S_ALU_OR_K,
BPF_S_ALU_OR_X,
BPF_S_ALU_XOR_K,
BPF_S_ALU_XOR_X,
BPF_S_ALU_LSH_K,
BPF_S_ALU_LSH_X,
BPF_S_ALU_RSH_K,

12
net/core/filter.c
View File

@ -187,6 +187,13 @@ unsigned int sk_run_filter(const struct sk_buff *skb,
case BPF_S_ALU_OR_K:
A |= K;
continue;
case BPF_S_ANC_ALU_XOR_X:
case BPF_S_ALU_XOR_X:
A ^= X;
continue;
case BPF_S_ALU_XOR_K:
A ^= K;
continue;
case BPF_S_ALU_LSH_X:
A <<= X;
continue;
@ -334,9 +341,6 @@ load_b:
case BPF_S_ANC_CPU:
A = raw_smp_processor_id();
continue;
case BPF_S_ANC_ALU_XOR_X:
A ^= X;
continue;
case BPF_S_ANC_NLATTR: {
struct nlattr *nla;
@ -483,6 +487,8 @@ int sk_chk_filter(struct sock_filter *filter, unsigned int flen)
[BPF_ALU|BPF_AND|BPF_X] = BPF_S_ALU_AND_X,
[BPF_ALU|BPF_OR|BPF_K] = BPF_S_ALU_OR_K,
[BPF_ALU|BPF_OR|BPF_X] = BPF_S_ALU_OR_X,
[BPF_ALU|BPF_XOR|BPF_K] = BPF_S_ALU_XOR_K,
[BPF_ALU|BPF_XOR|BPF_X] = BPF_S_ALU_XOR_X,
[BPF_ALU|BPF_LSH|BPF_K] = BPF_S_ALU_LSH_K,
[BPF_ALU|BPF_LSH|BPF_X] = BPF_S_ALU_LSH_X,
[BPF_ALU|BPF_RSH|BPF_K] = BPF_S_ALU_RSH_K,