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authorMichal Sekletar <msekleta@redhat.com>2015-03-24 14:48:41 +0100
committerDavid S. Miller <davem@davemloft.net>2015-03-24 15:25:15 -0400
commit27cd5452476978283decb19e429e81fc6c71e74b (patch)
treea147d4576190e18580589e6faaf08e1b7050ef2d /net/core
parentf6bb76cd4d8552bada1e454c291419f893e1af7b (diff)
filter: introduce SKF_AD_VLAN_TPID BPF extension
If vlan offloading takes place then vlan header is removed from frame and its contents, both vlan_tci and vlan_proto, is available to user space via TPACKET interface. However, only vlan_tci can be used in BPF filters. This commit introduces a new BPF extension. It makes possible to load the value of vlan_proto (vlan TPID) to register A. Support for classic BPF and eBPF is being added, analogous to skb->protocol. Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Jiri Pirko <jpirko@redhat.com> Signed-off-by: Michal Sekletar <msekleta@redhat.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Reviewed-by: Jiri Pirko <jiri@resnulli.us> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core')
-rw-r--r--net/core/filter.c17
1 files changed, 17 insertions, 0 deletions
diff --git a/net/core/filter.c b/net/core/filter.c
index 084eacc4d1d4..32f43c59908c 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -272,6 +272,16 @@ static bool convert_bpf_extensions(struct sock_filter *fp,
insn += cnt - 1;
break;
+ case SKF_AD_OFF + SKF_AD_VLAN_TPID:
+ BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_proto) != 2);
+
+ /* A = *(u16 *) (CTX + offsetof(vlan_proto)) */
+ *insn++ = BPF_LDX_MEM(BPF_H, BPF_REG_A, BPF_REG_CTX,
+ offsetof(struct sk_buff, vlan_proto));
+ /* A = ntohs(A) [emitting a nop or swap16] */
+ *insn = BPF_ENDIAN(BPF_FROM_BE, BPF_REG_A, 16);
+ break;
+
case SKF_AD_OFF + SKF_AD_PAY_OFFSET:
case SKF_AD_OFF + SKF_AD_NLATTR:
case SKF_AD_OFF + SKF_AD_NLATTR_NEST:
@@ -1226,6 +1236,13 @@ static u32 sk_filter_convert_ctx_access(int dst_reg, int src_reg, int ctx_off,
offsetof(struct sk_buff, protocol));
break;
+ case offsetof(struct __sk_buff, vlan_proto):
+ BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_proto) != 2);
+
+ *insn++ = BPF_LDX_MEM(BPF_H, dst_reg, src_reg,
+ offsetof(struct sk_buff, vlan_proto));
+ break;
+
case offsetof(struct __sk_buff, mark):
return convert_skb_access(SKF_AD_MARK, dst_reg, src_reg, insn);