static void
dctcp_ack_received(struct cc_var *ccv, uint16_t type)
{
struct dctcp *dctcp_data;
int bytes_acked = 0;
dctcp_data = ccv->cc_data;
if (CCV(ccv, t_flags) & TF_ECN_PERMIT) {
/*
* DCTCP doesn't treat receipt of ECN marked packet as a
* congestion event. Thus, DCTCP always executes the ACK
* processing out of congestion recovery.
*/
if (IN_CONGRECOVERY(CCV(ccv, t_flags))) {
EXIT_CONGRECOVERY(CCV(ccv, t_flags));
newreno_cc_algo.ack_received(ccv, type);
ENTER_CONGRECOVERY(CCV(ccv, t_flags));
} else
newreno_cc_algo.ack_received(ccv, type);
if (type == CC_DUPACK)
bytes_acked = CCV(ccv, t_maxseg);
if (type == CC_ACK)
bytes_acked = ccv->bytes_this_ack;
/* Update total bytes. */
dctcp_data->bytes_total += bytes_acked;
/* Update total marked bytes. */
if (dctcp_data->ece_curr) {
if (!dctcp_data->ece_prev
&& bytes_acked > CCV(ccv, t_maxseg)) {
dctcp_data->bytes_ecn +=
(bytes_acked - CCV(ccv, t_maxseg));
} else
dctcp_data->bytes_ecn += bytes_acked;
dctcp_data->ece_prev = 1;
} else {
if (dctcp_data->ece_prev
&& bytes_acked > CCV(ccv, t_maxseg))
dctcp_data->bytes_ecn += CCV(ccv, t_maxseg);
dctcp_data->ece_prev = 0;
}
dctcp_data->ece_curr = 0;
/*
* Update the fraction of marked bytes at the end of
* current window size.
*/
if ((IN_FASTRECOVERY(CCV(ccv, t_flags)) &&
SEQ_GEQ(ccv->curack, CCV(ccv, snd_recover))) ||
(!IN_FASTRECOVERY(CCV(ccv, t_flags)) &&
SEQ_GT(ccv->curack, dctcp_data->save_sndnxt)))
dctcp_update_alpha(ccv);
} else
newreno_cc_algo.ack_received(ccv, type);
}
/*
* Perform any necessary tasks before we enter congestion recovery.
*/
static void
newreno_cong_signal(struct cc_var *ccv, uint32_t type)
{
uint32_t cwin, ssthresh_on_loss;
u_int mss;
cwin = CCV(ccv, snd_cwnd);
mss = CCV(ccv, t_maxseg);
ssthresh_on_loss =
max((CCV(ccv, snd_max) - CCV(ccv, snd_una)) / 2 / mss, 2)
* mss;
/* Catch algos which mistakenly leak private signal types. */
KASSERT((type & CC_SIGPRIVMASK) == 0,
("%s: congestion signal type 0x%08x is private\n", __func__, type));
cwin = max(cwin / 2 / mss, 2) * mss;
switch (type) {
case CC_NDUPACK:
if (!IN_FASTRECOVERY(CCV(ccv, t_flags))) {
if (!IN_CONGRECOVERY(CCV(ccv, t_flags))) {
CCV(ccv, snd_ssthresh) = ssthresh_on_loss;
CCV(ccv, snd_cwnd) = cwin;
}
ENTER_RECOVERY(CCV(ccv, t_flags));
}
break;
case CC_ECN:
if (!IN_CONGRECOVERY(CCV(ccv, t_flags))) {
CCV(ccv, snd_ssthresh) = ssthresh_on_loss;
CCV(ccv, snd_cwnd) = cwin;
ENTER_CONGRECOVERY(CCV(ccv, t_flags));
}
break;
case CC_RTO:
CCV(ccv, snd_ssthresh) = ssthresh_on_loss;
CCV(ccv, snd_cwnd) = mss;
break;
}
}
/*
* Perform any necessary tasks before we enter congestion recovery.
*/
static void
dctcp_cong_signal(struct cc_var *ccv, uint32_t type)
{
struct dctcp *dctcp_data;
u_int win, mss;
dctcp_data = ccv->cc_data;
win = CCV(ccv, snd_cwnd);
mss = CCV(ccv, t_maxseg);
switch (type) {
case CC_NDUPACK:
if (!IN_FASTRECOVERY(CCV(ccv, t_flags))) {
if (!IN_CONGRECOVERY(CCV(ccv, t_flags))) {
CCV(ccv, snd_ssthresh) = mss *
max(win / 2 / mss, 2);
dctcp_data->num_cong_events++;
} else {
/* cwnd has already updated as congestion
* recovery. Reverse cwnd value using
* snd_cwnd_prev and recalculate snd_ssthresh
*/
win = CCV(ccv, snd_cwnd_prev);
CCV(ccv, snd_ssthresh) =
max(win / 2 / mss, 2) * mss;
}
ENTER_RECOVERY(CCV(ccv, t_flags));
}
break;
case CC_ECN:
/*
* Save current snd_cwnd when the host encounters both
* congestion recovery and fast recovery.
*/
CCV(ccv, snd_cwnd_prev) = win;
if (!IN_CONGRECOVERY(CCV(ccv, t_flags))) {
if (V_dctcp_slowstart &&
dctcp_data->num_cong_events++ == 0) {
CCV(ccv, snd_ssthresh) =
mss * max(win / 2 / mss, 2);
dctcp_data->alpha = MAX_ALPHA_VALUE;
dctcp_data->bytes_ecn = 0;
dctcp_data->bytes_total = 0;
dctcp_data->save_sndnxt = CCV(ccv, snd_nxt);
} else
CCV(ccv, snd_ssthresh) = max((win - ((win *
dctcp_data->alpha) >> 11)) / mss, 2) * mss;
CCV(ccv, snd_cwnd) = CCV(ccv, snd_ssthresh);
ENTER_CONGRECOVERY(CCV(ccv, t_flags));
}
dctcp_data->ece_curr = 1;
break;
case CC_RTO:
if (CCV(ccv, t_flags) & TF_ECN_PERMIT) {
CCV(ccv, t_flags) |= TF_ECN_SND_CWR;
dctcp_update_alpha(ccv);
dctcp_data->save_sndnxt += CCV(ccv, t_maxseg);
dctcp_data->num_cong_events++;
}
break;
}
}
