This patch adds bpf_setsockopt(TCP_BPF_RTO_MIN) to allow bpf prog
to set the min rto of a connection. It could be used together
with the earlier patch which has added bpf_setsockopt(TCP_BPF_DELACK_MAX).
A later selftest patch will communicate the max delay ack in a
bpf tcp header option and then the receiving side can use
bpf_setsockopt(TCP_BPF_RTO_MIN) to set a shorter rto.
Acked-by: John Fastabend <john.fastabend@xxxxxxxxx>
Reviewed-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: Martin KaFai Lau <kafai@xxxxxx>
---
include/net/inet_connection_sock.h | 1 +
include/net/tcp.h | 2 +-
include/uapi/linux/bpf.h | 1 +
net/core/filter.c | 7 +++++++
net/ipv4/tcp.c | 2 ++
tools/include/uapi/linux/bpf.h | 1 +
6 files changed, 13 insertions(+), 1 deletion(-)
diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h
index da7264a1ebfc..c738abeb3265 100644
--- a/include/net/inet_connection_sock.h
+++ b/include/net/inet_connection_sock.h
@@ -86,6 +86,7 @@ struct inet_connection_sock {
struct timer_list icsk_retransmit_timer;
struct timer_list icsk_delack_timer;
__u32 icsk_rto;
+ __u32 icsk_rto_min;
__u32 icsk_delack_max;
__u32 icsk_pmtu_cookie;
const struct tcp_congestion_ops *icsk_ca_ops;
diff --git a/include/net/tcp.h b/include/net/tcp.h
index eab6c7510b5b..dda778c782fe 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -699,7 +699,7 @@ static inline void tcp_fast_path_check(struct sock *sk)
static inline u32 tcp_rto_min(struct sock *sk)
{
const struct dst_entry *dst = __sk_dst_get(sk);
- u32 rto_min = TCP_RTO_MIN;
+ u32 rto_min = inet_csk(sk)->icsk_rto_min;
if (dst && dst_metric_locked(dst, RTAX_RTO_MIN))
rto_min = dst_metric_rtt(dst, RTAX_RTO_MIN);
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index f5d9549c52dc..4bd75c12476b 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -4251,6 +4251,7 @@ enum {
TCP_BPF_IW = 1001, /* Set TCP initial congestion window */
TCP_BPF_SNDCWND_CLAMP = 1002, /* Set sndcwnd_clamp */
TCP_BPF_DELACK_MAX = 1003, /* Max delay ack in usecs */
+ TCP_BPF_RTO_MIN = 1004, /* Min delay ack in usecs */
};
struct bpf_perf_event_value {
diff --git a/net/core/filter.c b/net/core/filter.c
index 80fe7420f609..075ab71b985c 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -4488,6 +4488,13 @@ static int _bpf_setsockopt(struct sock *sk, int level, int optname,
return -EINVAL;
inet_csk(sk)->icsk_delack_max = timeout;
break;
+ case TCP_BPF_RTO_MIN:
+ timeout = usecs_to_jiffies(val);
+ if (timeout > TCP_RTO_MIN ||
+ timeout < TCP_TIMEOUT_MIN)
+ return -EINVAL;
+ inet_csk(sk)->icsk_rto_min = timeout;
+ break;
case TCP_SAVE_SYN:
if (val < 0 || val > 1)
ret = -EINVAL;
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 44c353a39ad4..6075cb091a20 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -418,6 +418,7 @@ void tcp_init_sock(struct sock *sk)
INIT_LIST_HEAD(&tp->tsorted_sent_queue);
icsk->icsk_rto = TCP_TIMEOUT_INIT;
+ icsk->icsk_rto_min = TCP_RTO_MIN;
icsk->icsk_delack_max = TCP_DELACK_MAX;
tp->mdev_us = jiffies_to_usecs(TCP_TIMEOUT_INIT);
minmax_reset(&tp->rtt_min, tcp_jiffies32, ~0U);
@@ -2686,6 +2687,7 @@ int tcp_disconnect(struct sock *sk, int flags)
icsk->icsk_backoff = 0;
icsk->icsk_probes_out = 0;
icsk->icsk_rto = TCP_TIMEOUT_INIT;
+ icsk->icsk_rto_min = TCP_RTO_MIN;
icsk->icsk_delack_max = TCP_DELACK_MAX;
tp->snd_ssthresh = TCP_INFINITE_SSTHRESH;
tp->snd_cwnd = TCP_INIT_CWND;
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index f5d9549c52dc..4bd75c12476b 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -4251,6 +4251,7 @@ enum {
TCP_BPF_IW = 1001, /* Set TCP initial congestion window */
TCP_BPF_SNDCWND_CLAMP = 1002, /* Set sndcwnd_clamp */
TCP_BPF_DELACK_MAX = 1003, /* Max delay ack in usecs */
+ TCP_BPF_RTO_MIN = 1004, /* Min delay ack in usecs */
};
struct bpf_perf_event_value {
--
2.24.1
