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authorJohn Fastabend <john.fastabend@gmail.com>2017-10-18 17:10:36 +0300
committerDavid S. Miller <davem@davemloft.net>2017-10-20 15:01:29 +0300
commit34f79502bbcfab659b8729da68b5e387f96eb4c1 (patch)
tree27084757c315fdf13c682c3d6c57922ed5f8447c /tools
parent435bf0d3f99a164df7e8c30428cef266b91d1d3b (diff)
downloadlinux-34f79502bbcfab659b8729da68b5e387f96eb4c1.tar.xz
bpf: avoid preempt enable/disable in sockmap using tcp_skb_cb region
SK_SKB BPF programs are run from the socket/tcp context but early in the stack before much of the TCP metadata is needed in tcp_skb_cb. So we can use some unused fields to place BPF metadata needed for SK_SKB programs when implementing the redirect function. This allows us to drop the preempt disable logic. It does however require an API change so sk_redirect_map() has been updated to additionally provide ctx_ptr to skb. Note, we do however continue to disable/enable preemption around actual BPF program running to account for map updates. Signed-off-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'tools')
-rw-r--r--tools/include/uapi/linux/bpf.h3
-rw-r--r--tools/testing/selftests/bpf/bpf_helpers.h2
-rw-r--r--tools/testing/selftests/bpf/sockmap_verdict_prog.c4
3 files changed, 5 insertions, 4 deletions
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 43ab5c402f98..be9a631a69f7 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -569,9 +569,10 @@ union bpf_attr {
* @flags: reserved for future use
* Return: 0 on success or negative error code
*
- * int bpf_sk_redirect_map(map, key, flags)
+ * int bpf_sk_redirect_map(skb, map, key, flags)
* Redirect skb to a sock in map using key as a lookup key for the
* sock in map.
+ * @skb: pointer to skb
* @map: pointer to sockmap
* @key: key to lookup sock in map
* @flags: reserved for future use
diff --git a/tools/testing/selftests/bpf/bpf_helpers.h b/tools/testing/selftests/bpf/bpf_helpers.h
index 36fb9161b34a..b2e02bdcd098 100644
--- a/tools/testing/selftests/bpf/bpf_helpers.h
+++ b/tools/testing/selftests/bpf/bpf_helpers.h
@@ -65,7 +65,7 @@ static int (*bpf_xdp_adjust_head)(void *ctx, int offset) =
static int (*bpf_setsockopt)(void *ctx, int level, int optname, void *optval,
int optlen) =
(void *) BPF_FUNC_setsockopt;
-static int (*bpf_sk_redirect_map)(void *map, int key, int flags) =
+static int (*bpf_sk_redirect_map)(void *ctx, void *map, int key, int flags) =
(void *) BPF_FUNC_sk_redirect_map;
static int (*bpf_sock_map_update)(void *map, void *key, void *value,
unsigned long long flags) =
diff --git a/tools/testing/selftests/bpf/sockmap_verdict_prog.c b/tools/testing/selftests/bpf/sockmap_verdict_prog.c
index 9b99bd10807d..2cd2d552938b 100644
--- a/tools/testing/selftests/bpf/sockmap_verdict_prog.c
+++ b/tools/testing/selftests/bpf/sockmap_verdict_prog.c
@@ -61,8 +61,8 @@ int bpf_prog2(struct __sk_buff *skb)
bpf_printk("verdict: data[0] = redir(%u:%u)\n", map, sk);
if (!map)
- return bpf_sk_redirect_map(&sock_map_rx, sk, 0);
- return bpf_sk_redirect_map(&sock_map_tx, sk, 0);
+ return bpf_sk_redirect_map(skb, &sock_map_rx, sk, 0);
+ return bpf_sk_redirect_map(skb, &sock_map_tx, sk, 0);
}
char _license[] SEC("license") = "GPL";