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x86: bpf_jit_comp: add vlan tag support 

This patch is a follow-up for patch "net: filter: add vlan tag access"
to support the new VLAN_TAG/VLAN_TAG_PRESENT accessors in BPF JIT.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Ani Sinha <ani@aristanetworks.com>
Cc: Daniel Borkmann <danborkmann@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2012-10-27 02:26:22 +00:00 committed by David S. Miller
parent f3335031b9
commit 855ddb56d8
1 changed files with 21 additions and 0 deletions
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21
arch/x86/net/bpf_jit_comp.c
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@ -11,6 +11,7 @@
#include <asm/cacheflush.h>
#include <linux/netdevice.h>
#include <linux/filter.h>
#include <linux/if_vlan.h>
/*
* Conventions :
@ -212,6 +213,8 @@ void bpf_jit_compile(struct sk_filter *fp)
case BPF_S_ANC_MARK:
case BPF_S_ANC_RXHASH:
case BPF_S_ANC_CPU:
case BPF_S_ANC_VLAN_TAG:
case BPF_S_ANC_VLAN_TAG_PRESENT:
case BPF_S_ANC_QUEUE:
case BPF_S_LD_W_ABS:
case BPF_S_LD_H_ABS:
@ -515,6 +518,24 @@ void bpf_jit_compile(struct sk_filter *fp)
CLEAR_A();
#endif
break;
case BPF_S_ANC_VLAN_TAG:
case BPF_S_ANC_VLAN_TAG_PRESENT:
BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_tci) != 2);
if (is_imm8(offsetof(struct sk_buff, vlan_tci))) {
/* movzwl off8(%rdi),%eax */
EMIT4(0x0f, 0xb7, 0x47, offsetof(struct sk_buff, vlan_tci));
} else {
EMIT3(0x0f, 0xb7, 0x87); /* movzwl off32(%rdi),%eax */
EMIT(offsetof(struct sk_buff, vlan_tci), 4);
}
BUILD_BUG_ON(VLAN_TAG_PRESENT != 0x1000);
if (filter[i].code == BPF_S_ANC_VLAN_TAG) {
EMIT3(0x80, 0xe4, 0xef); /* and $0xef,%ah */
} else {
EMIT3(0xc1, 0xe8, 0x0c); /* shr $0xc,%eax */
EMIT3(0x83, 0xe0, 0x01); /* and $0x1,%eax */
}
break;
case BPF_S_LD_W_ABS:
func = CHOOSE_LOAD_FUNC(K, sk_load_word);
common_load: seen |= SEEN_DATAREF;