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Commit f3335031b9452baebfe49b8b5e55d3fe0c4677d1

Authored by Eric Dumazet
Committed by David S. Miller
1 parent 0f6ae8f14e
Exists in smarc-l5.0.0_1.0.0-ga and in 5 other branches imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga

net: filter: add vlan tag access 

BPF filters lack ability to access skb->vlan_tci

This patch adds two new ancillary accessors :

SKF_AD_VLAN_TAG         (44) mapped to vlan_tx_tag_get(skb)

SKF_AD_VLAN_TAG_PRESENT (48) mapped to vlan_tx_tag_present(skb)

This allows libpcap/tcpdump to use a kernel filter instead of
having to fallback to accept all packets, then filter them in
user space.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Suggested-by: Ani Sinha <ani@aristanetworks.com>
Suggested-by: Daniel Borkmann <danborkmann@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

Showing 3 changed files with 14 additions and 1 deletions Side-by-side Diff

include/linux/filter.h
Diff comments   View file @ f333503
... ... @@ -123,6 +123,8 @@
123 123 BPF_S_ANC_CPU,
124 124 BPF_S_ANC_ALU_XOR_X,
125 125 BPF_S_ANC_SECCOMP_LD_W,
  126 + BPF_S_ANC_VLAN_TAG,
  127 + BPF_S_ANC_VLAN_TAG_PRESENT,
126 128 };
127 129  
128 130 #endif /* __LINUX_FILTER_H__ */
include/uapi/linux/filter.h
Diff comments   View file @ f333503
... ... @@ -127,7 +127,9 @@
127 127 #define SKF_AD_RXHASH 32
128 128 #define SKF_AD_CPU 36
129 129 #define SKF_AD_ALU_XOR_X 40
130   -#define SKF_AD_MAX 44
  130 +#define SKF_AD_VLAN_TAG 44
  131 +#define SKF_AD_VLAN_TAG_PRESENT 48
  132 +#define SKF_AD_MAX 52
131 133 #define SKF_NET_OFF (-0x100000)
132 134 #define SKF_LL_OFF (-0x200000)
133 135  
... ... @@ -39,6 +39,7 @@
39 39 #include <linux/reciprocal_div.h>
40 40 #include <linux/ratelimit.h>
41 41 #include <linux/seccomp.h>
  42 +#include <linux/if_vlan.h>
42 43  
43 44 /* No hurry in this branch
44 45 *
... ... @@ -341,6 +342,12 @@
341 342 case BPF_S_ANC_CPU:
342 343 A = raw_smp_processor_id();
343 344 continue;
  345 + case BPF_S_ANC_VLAN_TAG:
  346 + A = vlan_tx_tag_get(skb);
  347 + continue;
  348 + case BPF_S_ANC_VLAN_TAG_PRESENT:
  349 + A = !!vlan_tx_tag_present(skb);
  350 + continue;
344 351 case BPF_S_ANC_NLATTR: {
345 352 struct nlattr *nla;
346 353  
... ... @@ -600,6 +607,8 @@
600 607 ANCILLARY(RXHASH);
601 608 ANCILLARY(CPU);
602 609 ANCILLARY(ALU_XOR_X);
  610 + ANCILLARY(VLAN_TAG);
  611 + ANCILLARY(VLAN_TAG_PRESENT);
603 612 }
604 613 }
605 614 ftest->code = code;