langspielplatte/tcp-roccet-kernel-module
1
1
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Adds ECN handling managed by ROCCET.

Browse Source
This commit is contained in:
Lukas Prause
2026-01-30 13:48:31 +01:00
parent 5ebd5c0cb7
commit c24b02231a
2 changed files with 28 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

31
tcp_roccet.c
View File

@@ -130,6 +130,7 @@ static inline void roccettcp_reset(struct roccettcp *ca)
ca->curr_min_rtt_timed.rtt = ~0U; ca->curr_min_rtt_timed.rtt = ~0U;
ca->curr_min_rtt_timed.time = ~0U; ca->curr_min_rtt_timed.time = ~0U;
ca->last_rtt = 0; ca->last_rtt = 0;
ca->ece_received = 0;
} }
static inline void update_min_rtt(struct sock *sk) static inline void update_min_rtt(struct sock *sk)
@@ -431,12 +432,17 @@ __bpf_kfunc static void roccettcp_cong_avoid(struct sock *sk, u32 ack,
if (now - ca->roccet_last_event_time_us <= 100 * USEC_PER_MSEC) if (now - ca->roccet_last_event_time_us <= 100 * USEC_PER_MSEC)
return; return;
/* Lift off: Detect an exit point for tcp slow start /* LAUNCH: Detect an exit point for tcp slow start
* in networks with large buffers of multiple BDP * in networks with large buffers of multiple BDP
* Like in cellular networks (5G, ...). * Like in cellular networks (5G, ...).
* Or exit LAUNCH if cwnd is too large for application layer
* data rate.
*/ */
if (tcp_in_slow_start(tp) && ca->curr_srRTT > sr_rtt_upper_bound &&
get_ack_rate_diff(ca) >= ack_rate_diff_ss) { if ((tcp_in_slow_start(tp) && ca->curr_srRTT > sr_rtt_upper_bound &&
get_ack_rate_diff(ca) >= ack_rate_diff_ss) ||
(!tcp_is_cwnd_limited(sk) && tcp_in_slow_start(tp))
) {
ca->epoch_start = 0; ca->epoch_start = 0;
/* Handle inital slow start. Here we observe the most problems */ /* Handle inital slow start. Here we observe the most problems */
@@ -487,7 +493,9 @@ __bpf_kfunc static void roccettcp_cong_avoid(struct sock *sk, u32 ack,
if (roccet_xj < sr_rtt_upper_bound) if (roccet_xj < sr_rtt_upper_bound)
roccet_xj = sr_rtt_upper_bound; roccet_xj = sr_rtt_upper_bound;
if (ca->curr_srRTT > roccet_xj && bw_limit_detect) { if (ca->curr_srRTT > roccet_xj && (bw_limit_detect || ca->ece_received)) {
if(ca->ece_received)
ca->ece_received = 0;
ca->epoch_start = 0; ca->epoch_start = 0;
ca->roccet_last_event_time_us = now; ca->roccet_last_event_time_us = now;
ca->cnt = 100 * tcp_snd_cwnd(tp); ca->cnt = 100 * tcp_snd_cwnd(tp);
@@ -527,7 +535,7 @@ __bpf_kfunc static u32 roccettcp_recalc_ssthresh(struct sock *sk)
/* Don't exit slow start if loss occurs. */ /* Don't exit slow start if loss occurs. */
if (tcp_in_slow_start(tp)) if (tcp_in_slow_start(tp))
return tcp_snd_cwnd(tp); return tcp_snd_cwnd(tp);
ca->epoch_start = 0; /* end of epoch */ ca->epoch_start = 0; /* end of epoch */
/* Wmax and fast convergence */ /* Wmax and fast convergence */
@@ -576,6 +584,18 @@ __bpf_kfunc static void roccettcp_acked(struct sock *sk,
} }
} }
__bpf_kfunc static void roccet_in_ack_event(struct sock *sk, u32 flags)
{
struct roccettcp *ca = inet_csk_ca(sk);
/* Handle ECE bit.
* Pocessing of ECE events is done in roccettcp_cong_avoid()
*/
if (flags & CA_ACK_ECE) {
ca->ece_received = 1;
}
}
static struct tcp_congestion_ops roccet_tcp __read_mostly = { static struct tcp_congestion_ops roccet_tcp __read_mostly = {
.init = roccettcp_init, .init = roccettcp_init,
.ssthresh = roccettcp_recalc_ssthresh, .ssthresh = roccettcp_recalc_ssthresh,
@@ -584,6 +604,7 @@ static struct tcp_congestion_ops roccet_tcp __read_mostly = {
.undo_cwnd = tcp_reno_undo_cwnd, .undo_cwnd = tcp_reno_undo_cwnd,
.cwnd_event = roccettcp_cwnd_event, .cwnd_event = roccettcp_cwnd_event,
.pkts_acked = roccettcp_acked, .pkts_acked = roccettcp_acked,
.in_ack_event = roccet_in_ack_event,
.owner = THIS_MODULE, .owner = THIS_MODULE,
.name = "roccet", .name = "roccet",
}; };

3
tcp_roccet.h
View File

@@ -39,7 +39,8 @@ struct roccettcp {
u32 tcp_cwnd; /* estimated tcp cwnd */ u32 tcp_cwnd; /* estimated tcp cwnd */
u32 curr_rtt; /* the minimum rtt of current round */ u32 curr_rtt; /* the minimum rtt of current round */
u32 roccet_last_event_time_us; /* The last time ROCCETv2 was triggered */ u32 roccet_last_event_time_us; /* The last time ROCCET was triggered */
u32 ece_received; /* Set to true if an ECE bit was received */
u32 curr_min_rtt; /* The current observed minRTT */ u32 curr_min_rtt; /* The current observed minRTT */
struct TimedRTT curr_min_rtt_timed; /* The current observed minRTT with struct TimedRTT curr_min_rtt_timed; /* The current observed minRTT with
the timestamp when it was observed */ the timestamp when it was observed */