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authorLawrence Brakmo <brakmo@fb.com>2017-06-30 20:02:53 -0700
committerDavid S. Miller <davem@davemloft.net>2017-07-01 16:15:14 -0700
commit13bf96411ad2bd162a4f9470d58c6bb579c96e21 (patch)
tree33d5d9ecfa19d4cc4752a888abf0b03ff42881c4
parentbpf: Sample BPF program to set initial cwnd (diff)
downloadwireguard-linux-13bf96411ad2bd162a4f9470d58c6bb579c96e21.tar.xz
wireguard-linux-13bf96411ad2bd162a4f9470d58c6bb579c96e21.zip
bpf: Adds support for setting sndcwnd clamp
Adds a new bpf_setsockopt for TCP sockets, TCP_BPF_SNDCWND_CLAMP, which sets the initial congestion window. It is useful to limit the sndcwnd when the host are close to each other (small RTT). Signed-off-by: Lawrence Brakmo <brakmo@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--include/uapi/linux/bpf.h1
-rw-r--r--net/core/filter.c7
2 files changed, 8 insertions, 0 deletions
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 32755b538652..a6a91e5e96fc 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -784,5 +784,6 @@ enum {
};
#define TCP_BPF_IW 1001 /* Set TCP initial congestion window */
+#define TCP_BPF_SNDCWND_CLAMP 1002 /* Set sndcwnd_clamp */
#endif /* _UAPI__LINUX_BPF_H__ */
diff --git a/net/core/filter.c b/net/core/filter.c
index 794be0a454f5..523b91d25025 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -2746,6 +2746,13 @@ BPF_CALL_5(bpf_setsockopt, struct bpf_sock_ops_kern *, bpf_sock,
else
tp->snd_cwnd = val;
break;
+ case TCP_BPF_SNDCWND_CLAMP:
+ if (val <= 0) {
+ ret = -EINVAL;
+ } else {
+ tp->snd_cwnd_clamp = val;
+ tp->snd_ssthresh = val;
+ }
default:
ret = -EINVAL;
}