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Commit 855ddb56 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

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: default avatarEric Dumazet <edumazet@google.com>
Cc: Ani Sinha <ani@aristanetworks.com>
Cc: Daniel Borkmann <danborkmann@iogearbox.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f3335031

arch/x86/net/bpf_jit_comp.c

+21 −0
Original line number Diff line number Diff line
@@ -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;