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| author | Alexei Starovoitov <ast@plumgrid.com> | 2015-06-04 20:11:53 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-06-07 12:01:33 +0300 |
| commit | 3431205e03977aaf32bce6d4b16fb8244b510056 (patch) | |
| tree | 0d9405acb8ac34a6bc5ad93a9b9ae674c4d3879e /samples | |
| parent | 98da81a426a76c351f3c2854d5bc31f17bba3194 (diff) | |
| download | linux-3431205e03977aaf32bce6d4b16fb8244b510056.tar.xz | |
bpf: make programs see skb->data == L2 for ingress and egress
eBPF programs attached to ingress and egress qdiscs see inconsistent skb->data.
For ingress L2 header is already pulled, whereas for egress it's present.
This is known to program writers which are currently forced to use
BPF_LL_OFF workaround.
Since programs don't change skb internal pointers it is safe to do
pull/push right around invocation of the program and earlier taps and
later pt->func() will not be affected.
Multiple taps via packet_rcv(), tpacket_rcv() are doing the same trick
around run_filter/BPF_PROG_RUN even if skb_shared.
This fix finally allows programs to use optimized LD_ABS/IND instructions
without BPF_LL_OFF for higher performance.
tc ingress + cls_bpf + samples/bpf/tcbpf1_kern.o
w/o JIT w/JIT
before 20.5 23.6 Mpps
after 21.8 26.6 Mpps
Old programs with BPF_LL_OFF will still work as-is.
We can now undo most of the earlier workaround commit:
a166151cbe33 ("bpf: fix bpf helpers to use skb->mac_header relative offsets")
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'samples')
| -rw-r--r-- | samples/bpf/tcbpf1_kern.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/samples/bpf/tcbpf1_kern.c b/samples/bpf/tcbpf1_kern.c index 7c27710f8296..9bfb2eb34563 100644 --- a/samples/bpf/tcbpf1_kern.c +++ b/samples/bpf/tcbpf1_kern.c @@ -21,7 +21,7 @@ static inline void set_dst_mac(struct __sk_buff *skb, char *mac) static inline void set_ip_tos(struct __sk_buff *skb, __u8 new_tos) { - __u8 old_tos = load_byte(skb, BPF_LL_OFF + TOS_OFF); + __u8 old_tos = load_byte(skb, TOS_OFF); bpf_l3_csum_replace(skb, IP_CSUM_OFF, htons(old_tos), htons(new_tos), 2); bpf_skb_store_bytes(skb, TOS_OFF, &new_tos, sizeof(new_tos), 0); @@ -34,7 +34,7 @@ static inline void set_ip_tos(struct __sk_buff *skb, __u8 new_tos) static inline void set_tcp_ip_src(struct __sk_buff *skb, __u32 new_ip) { - __u32 old_ip = _htonl(load_word(skb, BPF_LL_OFF + IP_SRC_OFF)); + __u32 old_ip = _htonl(load_word(skb, IP_SRC_OFF)); bpf_l4_csum_replace(skb, TCP_CSUM_OFF, old_ip, new_ip, IS_PSEUDO | sizeof(new_ip)); bpf_l3_csum_replace(skb, IP_CSUM_OFF, old_ip, new_ip, sizeof(new_ip)); @@ -44,7 +44,7 @@ static inline void set_tcp_ip_src(struct __sk_buff *skb, __u32 new_ip) #define TCP_DPORT_OFF (ETH_HLEN + sizeof(struct iphdr) + offsetof(struct tcphdr, dest)) static inline void set_tcp_dest_port(struct __sk_buff *skb, __u16 new_port) { - __u16 old_port = htons(load_half(skb, BPF_LL_OFF + TCP_DPORT_OFF)); + __u16 old_port = htons(load_half(skb, TCP_DPORT_OFF)); bpf_l4_csum_replace(skb, TCP_CSUM_OFF, old_port, new_port, sizeof(new_port)); bpf_skb_store_bytes(skb, TCP_DPORT_OFF, &new_port, sizeof(new_port), 0); @@ -53,7 +53,7 @@ static inline void set_tcp_dest_port(struct __sk_buff *skb, __u16 new_port) SEC("classifier") int bpf_prog1(struct __sk_buff *skb) { - __u8 proto = load_byte(skb, BPF_LL_OFF + ETH_HLEN + offsetof(struct iphdr, protocol)); + __u8 proto = load_byte(skb, ETH_HLEN + offsetof(struct iphdr, protocol)); long *value; if (proto == IPPROTO_TCP) { |