diff options
| author | Lawrence Brakmo <brakmo@fb.com> | 2018-01-25 16:14:10 -0800 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2018-01-25 16:41:14 -0800 |
| commit | b13d880721729384757f235166068c315326f4a1 (patch) | |
| tree | 7d117afdbf662f4bc89261885e547053fbed90f7 /include | |
| parent | de525be2ca2734865d29c4b67ddd29913b214906 (diff) | |
bpf: Adds field bpf_sock_ops_cb_flags to tcp_sock
Adds field bpf_sock_ops_cb_flags to tcp_sock and bpf_sock_ops. Its primary
use is to determine if there should be calls to sock_ops bpf program at
various points in the TCP code. The field is initialized to zero,
disabling the calls. A sock_ops BPF program can set it, per connection and
as necessary, when the connection is established.
It also adds support for reading and writting the field within a
sock_ops BPF program. Reading is done by accessing the field directly.
However, writing is done through the helper function
bpf_sock_ops_cb_flags_set, in order to return an error if a BPF program
is trying to set a callback that is not supported in the current kernel
(i.e. running an older kernel). The helper function returns 0 if it was
able to set all of the bits set in the argument, a positive number
containing the bits that could not be set, or -EINVAL if the socket is
not a full TCP socket.
Examples of where one could call the bpf program:
1) When RTO fires
2) When a packet is retransmitted
3) When the connection terminates
4) When a packet is sent
5) When a packet is received
Signed-off-by: Lawrence Brakmo <brakmo@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/tcp.h | 11 | ||||
| -rw-r--r-- | include/uapi/linux/bpf.h | 17 |
2 files changed, 27 insertions, 1 deletions
diff --git a/include/linux/tcp.h b/include/linux/tcp.h index 4f93f0953c41..8f4c54986f97 100644 --- a/include/linux/tcp.h +++ b/include/linux/tcp.h @@ -335,6 +335,17 @@ struct tcp_sock { int linger2; + +/* Sock_ops bpf program related variables */ +#ifdef CONFIG_BPF + u8 bpf_sock_ops_cb_flags; /* Control calling BPF programs + * values defined in uapi/linux/tcp.h + */ +#define BPF_SOCK_OPS_TEST_FLAG(TP, ARG) (TP->bpf_sock_ops_cb_flags & ARG) +#else +#define BPF_SOCK_OPS_TEST_FLAG(TP, ARG) 0 +#endif + /* Receiver side RTT estimation */ struct { u32 rtt_us; diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 8d5874c2c4ff..aa128407c44d 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -642,6 +642,14 @@ union bpf_attr { * @optlen: length of optval in bytes * Return: 0 or negative error * + * int bpf_sock_ops_cb_flags_set(bpf_sock_ops, flags) + * Set callback flags for sock_ops + * @bpf_sock_ops: pointer to bpf_sock_ops_kern struct + * @flags: flags value + * Return: 0 for no error + * -EINVAL if there is no full tcp socket + * bits in flags that are not supported by current kernel + * * int bpf_skb_adjust_room(skb, len_diff, mode, flags) * Grow or shrink room in sk_buff. * @skb: pointer to skb @@ -748,7 +756,8 @@ union bpf_attr { FN(perf_event_read_value), \ FN(perf_prog_read_value), \ FN(getsockopt), \ - FN(override_return), + FN(override_return), \ + FN(sock_ops_cb_flags_set), /* integer value in 'imm' field of BPF_CALL instruction selects which helper * function eBPF program intends to call @@ -969,8 +978,14 @@ struct bpf_sock_ops { */ __u32 snd_cwnd; __u32 srtt_us; /* Averaged RTT << 3 in usecs */ + __u32 bpf_sock_ops_cb_flags; /* flags defined in uapi/linux/tcp.h */ }; +/* Definitions for bpf_sock_ops_cb_flags */ +#define BPF_SOCK_OPS_ALL_CB_FLAGS 0 /* Mask of all currently + * supported cb flags + */ + /* List of known BPF sock_ops operators. * New entries can only be added at the end */ |