diff options
| author | Yuchung Cheng <ycheng@google.com> | 2018-10-08 15:32:20 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-10-10 22:26:00 -0700 |
| commit | ffd177dea5c1ee5b717961d041df0778d58f50c0 (patch) | |
| tree | be10e3a3a741632cf00de77b29ae51c4f1787aea /net/ipv4/tcp_dctcp.c | |
| parent | ed792e28c4bd09e9a319d2ad914aa62982cb4c4a (diff) | |
tcp: refactor DCTCP ECN ACK handling
DCTCP has two parts - a new ECN signalling mechanism and the response
function to it. The first part can be used by other congestion
control for DCTCP-ECN deployed networks. This patch moves that part
into a separate tcp_dctcp.h to be used by other congestion control
module (like how Yeah uses Vegas algorithmas). For example, BBR is
experimenting such ECN signal currently
https://tinyurl.com/ietf-102-iccrg-bbr2
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Yousuk Seung <ysseung@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_dctcp.c')
| -rw-r--r-- | net/ipv4/tcp_dctcp.c | 55 |
1 files changed, 4 insertions, 51 deletions
diff --git a/net/ipv4/tcp_dctcp.c b/net/ipv4/tcp_dctcp.c index ca61e2a659e7..cd4814f7e962 100644 --- a/net/ipv4/tcp_dctcp.c +++ b/net/ipv4/tcp_dctcp.c @@ -44,6 +44,7 @@ #include <linux/mm.h> #include <net/tcp.h> #include <linux/inet_diag.h> +#include "tcp_dctcp.h" #define DCTCP_MAX_ALPHA 1024U @@ -118,54 +119,6 @@ static u32 dctcp_ssthresh(struct sock *sk) return max(tp->snd_cwnd - ((tp->snd_cwnd * ca->dctcp_alpha) >> 11U), 2U); } -/* Minimal DCTP CE state machine: - * - * S: 0 <- last pkt was non-CE - * 1 <- last pkt was CE - */ - -static void dctcp_ce_state_0_to_1(struct sock *sk) -{ - struct dctcp *ca = inet_csk_ca(sk); - struct tcp_sock *tp = tcp_sk(sk); - - if (!ca->ce_state) { - /* State has changed from CE=0 to CE=1, force an immediate - * ACK to reflect the new CE state. If an ACK was delayed, - * send that first to reflect the prior CE state. - */ - if (inet_csk(sk)->icsk_ack.pending & ICSK_ACK_TIMER) - __tcp_send_ack(sk, ca->prior_rcv_nxt); - inet_csk(sk)->icsk_ack.pending |= ICSK_ACK_NOW; - } - - ca->prior_rcv_nxt = tp->rcv_nxt; - ca->ce_state = 1; - - tp->ecn_flags |= TCP_ECN_DEMAND_CWR; -} - -static void dctcp_ce_state_1_to_0(struct sock *sk) -{ - struct dctcp *ca = inet_csk_ca(sk); - struct tcp_sock *tp = tcp_sk(sk); - - if (ca->ce_state) { - /* State has changed from CE=1 to CE=0, force an immediate - * ACK to reflect the new CE state. If an ACK was delayed, - * send that first to reflect the prior CE state. - */ - if (inet_csk(sk)->icsk_ack.pending & ICSK_ACK_TIMER) - __tcp_send_ack(sk, ca->prior_rcv_nxt); - inet_csk(sk)->icsk_ack.pending |= ICSK_ACK_NOW; - } - - ca->prior_rcv_nxt = tp->rcv_nxt; - ca->ce_state = 0; - - tp->ecn_flags &= ~TCP_ECN_DEMAND_CWR; -} - static void dctcp_update_alpha(struct sock *sk, u32 flags) { const struct tcp_sock *tp = tcp_sk(sk); @@ -230,12 +183,12 @@ static void dctcp_state(struct sock *sk, u8 new_state) static void dctcp_cwnd_event(struct sock *sk, enum tcp_ca_event ev) { + struct dctcp *ca = inet_csk_ca(sk); + switch (ev) { case CA_EVENT_ECN_IS_CE: - dctcp_ce_state_0_to_1(sk); - break; case CA_EVENT_ECN_NO_CE: - dctcp_ce_state_1_to_0(sk); + dctcp_ece_ack_update(sk, ev, &ca->prior_rcv_nxt, &ca->ce_state); break; default: /* Don't care for the rest. */ |