diff options
| author | Viet Hoang Tran <hoang.tran@uclouvain.be> | 2019-04-15 09:54:55 +0000 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2019-04-16 19:24:20 -0700 |
| commit | 725721a6506eea53bfde81a34e91a06d6162c216 (patch) | |
| tree | de84ddb9807311eae13b1fe9cf1c6da32eed66c6 | |
| parent | 809041e765055ba311f3a0b8751db1c65739ad51 (diff) | |
| download | linux-725721a6506eea53bfde81a34e91a06d6162c216.tar.gz | |
bpf: allow clearing all sock_ops callback flags
The helper function bpf_sock_ops_cb_flags_set() can be used to both
set and clear the sock_ops callback flags. However, its current
behavior is not consistent. BPF program may clear a flag if more than
one were set, or replace a flag with another one, but cannot clear all
flags.
This patch also updates the documentation to clarify the ability to
clear flags of this helper function.
Signed-off-by: Hoang Tran <hoang.tran@uclouvain.be>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
| -rw-r--r-- | include/uapi/linux/bpf.h | 9 | ||||
| -rw-r--r-- | net/core/filter.c | 3 |
2 files changed, 9 insertions, 3 deletions
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 704bb69514a2..eaf2d3284248 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -1737,12 +1737,19 @@ union bpf_attr { * error if an eBPF program tries to set a callback that is not * supported in the current kernel. * - * The supported callback values that *argval* can combine are: + * *argval* is a flag array which can combine these flags: * * * **BPF_SOCK_OPS_RTO_CB_FLAG** (retransmission time out) * * **BPF_SOCK_OPS_RETRANS_CB_FLAG** (retransmission) * * **BPF_SOCK_OPS_STATE_CB_FLAG** (TCP state change) * + * Therefore, this function can be used to clear a callback flag by + * setting the appropriate bit to zero. e.g. to disable the RTO + * callback: + * + * **bpf_sock_ops_cb_flags_set(bpf_sock,** + * **bpf_sock->bpf_sock_ops_cb_flags & ~BPF_SOCK_OPS_RTO_CB_FLAG)** + * * Here are some examples of where one could call such eBPF * program: * diff --git a/net/core/filter.c b/net/core/filter.c index bd1f51907b83..1833926a63fc 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -4437,8 +4437,7 @@ BPF_CALL_2(bpf_sock_ops_cb_flags_set, struct bpf_sock_ops_kern *, bpf_sock, if (!IS_ENABLED(CONFIG_INET) || !sk_fullsock(sk)) return -EINVAL; - if (val) - tcp_sk(sk)->bpf_sock_ops_cb_flags = val; + tcp_sk(sk)->bpf_sock_ops_cb_flags = val; return argval & (~BPF_SOCK_OPS_ALL_CB_FLAGS); } |