ARM: net: bpf_jit_32: add VLAN instructions for BPF JIT

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: Daniel Borkmann <daniel.borkmann@tik.ee.ethz.ch>
Cc: Mircea Gherzan <mgherzan@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Acked-by: Mircea Gherzan <mgherzan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 14 insertions, 0 deletions

diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c
index 8be702de34f9..9af9a690dbda 100644
--- a/arch/arm/net/bpf_jit_32.c
+++ b/arch/arm/net/bpf_jit_32.c
@@ -16,6 +16,7 @@
 #include <linux/netdevice.h>
 #include <linux/string.h>
 #include <linux/slab.h>
+#include <linux/if_vlan.h>
 #include <asm/cacheflush.h>
 #include <asm/hwcap.h>
 
@@ -168,6 +169,8 @@ static inline bool is_load_to_a(u16 inst)
         case BPF_S_ANC_MARK:
         case BPF_S_ANC_PROTOCOL:
         case BPF_S_ANC_RXHASH:
+        case BPF_S_ANC_VLAN_TAG:
+        case BPF_S_ANC_VLAN_TAG_PRESENT:
         case BPF_S_ANC_QUEUE:
                 return true;
         default:
@@ -815,6 +818,17 @@ b_epilogue:
                         off = offsetof(struct sk_buff, rxhash);
                         emit(ARM_LDR_I(r_A, r_skb, off), ctx);
                         break;
+                case BPF_S_ANC_VLAN_TAG:
+                case BPF_S_ANC_VLAN_TAG_PRESENT:
+                        ctx->seen |= SEEN_SKB;
+                        BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_tci) != 2);
+                        off = offsetof(struct sk_buff, vlan_tci);
+                        emit(ARM_LDRH_I(r_A, r_skb, off), ctx);
+                        if (inst->code == BPF_S_ANC_VLAN_TAG)
+                                OP_IMM3(ARM_AND, r_A, r_A, VLAN_VID_MASK, ctx);
+                        else
+                                OP_IMM3(ARM_AND, r_A, r_A, VLAN_TAG_PRESENT, ctx);
+                        break;
                 case BPF_S_ANC_QUEUE:
                         ctx->seen |= SEEN_SKB;
                         BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff,