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Commit 9e49e889 authored by Daniel Borkmann's avatar Daniel Borkmann Committed by David S. Miller
Browse files

filter: add XOR instruction for use with X/K 



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: default avatarDaniel Borkmann <daniel.borkmann@tik.ee.ethz.ch>
Acked-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 718cffc4

include/linux/filter.h

+3 −0
Original line number Diff line number Diff line
@@ -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,

net/core/filter.c

+9 −3
Original line number Diff line number Diff line
@@ -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 @@ unsigned int sk_run_filter(const struct sk_buff *skb, 
		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,