[PATCH net-next 1/2] net: filter: add vlan tag access
DORMANTno replies
From: Eric Dumazet <hidden>
Date: 2012-10-27 12:26:22
Subsystem:
bpf [core], bpf [general] (safe dynamic programs and tools), bpf [networking] (tcx & tc bpf, sock_addr), networking [general], the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Eric Dumazet <redacted> 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 <redacted> Suggested-by: Ani Sinha <redacted> Suggested-by: Daniel Borkmann <redacted> --- include/linux/filter.h | 2 ++ include/uapi/linux/filter.h | 4 +++- net/core/filter.c | 9 +++++++++ 3 files changed, 14 insertions(+), 1 deletion(-)
diff --git a/include/linux/filter.h b/include/linux/filter.h
index 24d251f..c9f0005 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h@@ -123,6 +123,8 @@ enum { BPF_S_ANC_CPU, BPF_S_ANC_ALU_XOR_X, BPF_S_ANC_SECCOMP_LD_W, + BPF_S_ANC_VLAN_TAG, + BPF_S_ANC_VLAN_TAG_PRESENT, }; #endif /* __LINUX_FILTER_H__ */
diff --git a/include/uapi/linux/filter.h b/include/uapi/linux/filter.h
index 3d79224..9cfde69 100644
--- a/include/uapi/linux/filter.h
+++ b/include/uapi/linux/filter.h@@ -127,7 +127,9 @@ struct sock_fprog { /* Required for SO_ATTACH_FILTER. */ #define SKF_AD_RXHASH 32 #define SKF_AD_CPU 36 #define SKF_AD_ALU_XOR_X 40 -#define SKF_AD_MAX 44 +#define SKF_AD_VLAN_TAG 44 +#define SKF_AD_VLAN_TAG_PRESENT 48 +#define SKF_AD_MAX 52 #define SKF_NET_OFF (-0x100000) #define SKF_LL_OFF (-0x200000)
diff --git a/net/core/filter.c b/net/core/filter.c
index 3d92ebb..5a114d4 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c@@ -39,6 +39,7 @@ #include <linux/reciprocal_div.h> #include <linux/ratelimit.h> #include <linux/seccomp.h> +#include <linux/if_vlan.h> /* No hurry in this branch *
@@ -341,6 +342,12 @@ load_b: case BPF_S_ANC_CPU: A = raw_smp_processor_id(); continue; + case BPF_S_ANC_VLAN_TAG: + A = vlan_tx_tag_get(skb); + continue; + case BPF_S_ANC_VLAN_TAG_PRESENT: + A = !!vlan_tx_tag_present(skb); + continue; case BPF_S_ANC_NLATTR: { struct nlattr *nla;
@@ -600,6 +607,8 @@ int sk_chk_filter(struct sock_filter *filter, unsigned int flen) ANCILLARY(RXHASH); ANCILLARY(CPU); ANCILLARY(ALU_XOR_X); + ANCILLARY(VLAN_TAG); + ANCILLARY(VLAN_TAG_PRESENT); } } ftest->code = code;