This patch adds two new arguments for cong_control of struct
tcp_congestion_ops:
- ack
- flag
These two arguments are inherited from the caller tcp_cong_control in
tcp_intput.c. One use case of them is to update cwnd and pacing rate
inside cong_control based on the info they provide. For example, the
flag can be used to decide if it is the right time to raise or reduce a
sender's cwnd.
Another change in this patch is to allow the write of tp->snd_cwnd_stamp
for a bpf tcp ca program. An use case of writing this field is to keep
track of the time whenever tp->snd_cwnd is raised or reduced inside the
cong_control callback.
Signed-off-by: Miao Xu <miaxu@xxxxxxxx>
---
include/net/tcp.h | 2 +-
net/ipv4/bpf_tcp_ca.c | 6 +++++-
net/ipv4/tcp_bbr.c | 2 +-
net/ipv4/tcp_input.c | 2 +-
4 files changed, 8 insertions(+), 4 deletions(-)
diff --git a/include/net/tcp.h b/include/net/tcp.h
index b935e1ae4caf..b37b8219060a 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1167,7 +1167,7 @@ struct tcp_congestion_ops {
/* call when packets are delivered to update cwnd and pacing rate,
* after all the ca_state processing. (optional)
*/
- void (*cong_control)(struct sock *sk, const struct rate_sample *rs);
+ void (*cong_control)(struct sock *sk, u32 ack, int flag, const struct rate_sample *rs);
/* new value of cwnd after loss (required) */
diff --git a/net/ipv4/bpf_tcp_ca.c b/net/ipv4/bpf_tcp_ca.c
index 7f518ea5f4ac..18227757ec0c 100644
--- a/net/ipv4/bpf_tcp_ca.c
+++ b/net/ipv4/bpf_tcp_ca.c
@@ -107,6 +107,9 @@ static int bpf_tcp_ca_btf_struct_access(struct bpf_verifier_log *log,
case offsetof(struct tcp_sock, snd_cwnd_cnt):
end = offsetofend(struct tcp_sock, snd_cwnd_cnt);
break;
+ case offsetof(struct tcp_sock, snd_cwnd_stamp):
+ end = offsetofend(struct tcp_sock, snd_cwnd_stamp);
+ break;
case offsetof(struct tcp_sock, snd_ssthresh):
end = offsetofend(struct tcp_sock, snd_ssthresh);
break;
@@ -307,7 +310,8 @@ static u32 bpf_tcp_ca_min_tso_segs(struct sock *sk)
return 0;
}
-static void bpf_tcp_ca_cong_control(struct sock *sk, const struct rate_sample *rs)
+static void bpf_tcp_ca_cong_control(struct sock *sk, u32 ack, int flag,
+ const struct rate_sample *rs)
{
}
diff --git a/net/ipv4/tcp_bbr.c b/net/ipv4/tcp_bbr.c
index 05dc2d05bc7c..c13d263dae06 100644
--- a/net/ipv4/tcp_bbr.c
+++ b/net/ipv4/tcp_bbr.c
@@ -1024,7 +1024,7 @@ static void bbr_update_model(struct sock *sk, const struct rate_sample *rs)
bbr_update_gains(sk);
}
-__bpf_kfunc static void bbr_main(struct sock *sk, const struct rate_sample *rs)
+__bpf_kfunc static void bbr_main(struct sock *sk, u32 ack, int flag, const struct rate_sample *rs)
{
struct bbr *bbr = inet_csk_ca(sk);
u32 bw;
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 384fa5e2f065..661dca9e3895 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -3541,7 +3541,7 @@ static void tcp_cong_control(struct sock *sk, u32 ack, u32 acked_sacked,
const struct inet_connection_sock *icsk = inet_csk(sk);
if (icsk->icsk_ca_ops->cong_control) {
- icsk->icsk_ca_ops->cong_control(sk, rs);
+ icsk->icsk_ca_ops->cong_control(sk, ack, flag, rs);
return;
}
--
2.43.0
