[PATCH net-next v5 12/16] bpf: Adds support for setting initial cwnd
From: Lawrence Brakmo <hidden>
Date: 2017-06-30 20:07:23
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [networking] (tcx & tc bpf, sock_addr), networking [general], the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Martin KaFai Lau, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Adds a new bpf_setsockopt for TCP sockets, TCP_BPF_IW, which sets the initial congestion window. This can be used when the hosts are far apart (large RTTs) and it is safe to start with a large inital cwnd. Signed-off-by: Lawrence Brakmo <redacted> --- include/uapi/linux/bpf.h | 2 ++ net/core/filter.c | 14 +++++++++++++- 2 files changed, 15 insertions(+), 1 deletion(-)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index cc47259..32755b5 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h@@ -783,4 +783,6 @@ enum { */ }; +#define TCP_BPF_IW 1001 /* Set TCP initial congestion window */ + #endif /* _UAPI__LINUX_BPF_H__ */
diff --git a/net/core/filter.c b/net/core/filter.c
index 96ceded..a4695cf 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c@@ -2725,7 +2725,19 @@ BPF_CALL_5(bpf_setsockopt, struct bpf_sock_ops_kern *, bpf_sock, tcp_reinit_congestion_control(sk, inet_csk(sk)->icsk_ca_ops); } else { - ret = -EINVAL; + struct tcp_sock *tp = tcp_sk(sk); + + val = *((int *)optval); + switch (optname) { + case TCP_BPF_IW: + if (val <= 0 || tp->data_segs_out > 0) + ret = -EINVAL; + else + tp->snd_cwnd = val; + break; + default: + ret = -EINVAL; + } } #else ret = -EINVAL;
--
2.9.3