diff options
| author |   Martin KaFai Lau <kafai@fb.com> | 2020-01-08 16:45:51 -0800 |
|---|---|---|
| committer |   Alexei Starovoitov <ast@kernel.org> | 2020-01-09 08:46:18 -0800 |
| commit | 206057fe020ac5c037d5e2dd6562a9bd216ec765 (patch) | |
| tree | 4e4b87e6b400b03b472793c007485d5df57584a9 | |
| parent | bpf: tcp: Support tcp_congestion_ops in bpf (diff) | |
| download | linux-dev-206057fe020ac5c037d5e2dd6562a9bd216ec765.tar.xz linux-dev-206057fe020ac5c037d5e2dd6562a9bd216ec765.zip | |
bpf: Add BPF_FUNC_tcp_send_ack helper
Add a helper to send out a tcp-ack. It will be used in the later
bpf_dctcp implementation that requires to send out an ack
when the CE state changed.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200109004551.3900448-1-kafai@fb.com
| -rw-r--r-- | include/uapi/linux/bpf.h | 11 | ||||
| -rw-r--r-- | net/ipv4/bpf_tcp_ca.c | 24 |
2 files changed, 33 insertions, 2 deletions
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 38059880963e..2d6a2e572f56 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -2837,6 +2837,14 @@ union bpf_attr { * Return * On success, the strictly positive length of the string, including * the trailing NUL character. On error, a negative value. + * + * int bpf_tcp_send_ack(void *tp, u32 rcv_nxt) + * Description + * Send out a tcp-ack. *tp* is the in-kernel struct tcp_sock. + * *rcv_nxt* is the ack_seq to be sent out. + * Return + * 0 on success, or a negative error in case of failure. + * */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -2954,7 +2962,8 @@ union bpf_attr { FN(probe_read_user), \ FN(probe_read_kernel), \ FN(probe_read_user_str), \ - FN(probe_read_kernel_str), + FN(probe_read_kernel_str), \ + FN(tcp_send_ack), /* integer value in 'imm' field of BPF_CALL instruction selects which helper * function eBPF program intends to call diff --git a/net/ipv4/bpf_tcp_ca.c b/net/ipv4/bpf_tcp_ca.c index 9c7745b958d7..574972bc7299 100644 --- a/net/ipv4/bpf_tcp_ca.c +++ b/net/ipv4/bpf_tcp_ca.c @@ -143,11 +143,33 @@ static int bpf_tcp_ca_btf_struct_access(struct bpf_verifier_log *log, return NOT_INIT; } +BPF_CALL_2(bpf_tcp_send_ack, struct tcp_sock *, tp, u32, rcv_nxt) +{ + /* bpf_tcp_ca prog cannot have NULL tp */ + __tcp_send_ack((struct sock *)tp, rcv_nxt); + return 0; +} + +static const struct bpf_func_proto bpf_tcp_send_ack_proto = { + .func = bpf_tcp_send_ack, + .gpl_only = false, + /* In case we want to report error later */ + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_BTF_ID, + .arg2_type = ARG_ANYTHING, + .btf_id = &tcp_sock_id, +}; + static const struct bpf_func_proto * bpf_tcp_ca_get_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { - return bpf_base_func_proto(func_id); + switch (func_id) { + case BPF_FUNC_tcp_send_ack: + return &bpf_tcp_send_ack_proto; + default: + return bpf_base_func_proto(func_id); + } } static const struct bpf_verifier_ops bpf_tcp_ca_verifier_ops = { |