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- Start sequence numbers at zero instead of one; the rest of the

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world seems to interpret the spec this way
- Initialize transmit window to two instead of one; helps get things
  going initially when the first packet may get dropped
- Really fix the shutdown + timeout race condition this time
This commit is contained in:
Archie Cobbs 2000-06-26 19:43:24 +00:00
parent 7731ee5af9
commit 3cd7db2297
1 changed files with 57 additions and 84 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

141
sys/netgraph/ng_pptpgre.c
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@ -136,11 +136,11 @@ struct ng_pptpgre_ackp {
int32_t rtt; /* round trip time estimate */
int32_t dev; /* deviation estimate */
u_int16_t xmitWin; /* size of xmit window */
u_char sackTimerRunning;/* send ack timer is running */
u_char rackTimerRunning;/* recv ack timer is running */
u_int32_t winAck; /* seq when xmitWin will grow */
struct callout_handle sackTimer; /* send ack timer */
struct callout_handle rackTimer; /* recv ack timer */
node_p *sackTimerPtr; /* send ack timer pointer */
node_p *rackTimerPtr; /* recv ack timer pointer */
u_int32_t winAck; /* seq when xmitWin will grow */
pptptime_t timeSent[PPTP_XMIT_WIN];
};
@ -177,8 +177,6 @@ static int ng_pptpgre_xmit(node_p node, struct mbuf *m, meta_p meta);
static int ng_pptpgre_recv(node_p node, struct mbuf *m, meta_p meta);
static void ng_pptpgre_start_send_ack_timer(node_p node, long ackTimeout);
static void ng_pptpgre_start_recv_ack_timer(node_p node);
static void ng_pptpgre_stop_send_ack_timer(node_p node);
static void ng_pptpgre_stop_recv_ack_timer(node_p node);
static void ng_pptpgre_recv_ack_timeout(void *arg);
static void ng_pptpgre_send_ack_timeout(void *arg);
static void ng_pptpgre_reset(node_p node);
@ -419,7 +417,7 @@ ng_pptpgre_rmnode(node_p node)
{
const priv_p priv = node->private;
/* Cancel timers */
/* Reset node */
ng_pptpgre_reset(node);
/* Take down netgraph node */
@ -513,7 +511,7 @@ ng_pptpgre_xmit(node_p node, struct mbuf *m, meta_p meta)
gre->hasAck = 1;
priv->xmitAck = priv->recvSeq;
gre->data[gre->hasSeq] = htonl(priv->xmitAck);
ng_pptpgre_stop_send_ack_timer(node);
a->sackTimerPtr = NULL;
}
/* Prepend GRE header to outgoing frame */
@ -670,20 +668,19 @@ badAck:
priv->recvSeq = seq;
/* We need to acknowledge this packet; do it soon... */
if (!a->sackTimerRunning) {
long ackTimeout;
if (a->sackTimerPtr == NULL) {
long maxWait;
/* Take half of the estimated round trip time */
ackTimeout = (a->rtt >> 1);
maxWait = (a->rtt >> 1);
/* If too soon, just send one right now */
if (!priv->conf.enableDelayedAck)
ng_pptpgre_xmit(node, NULL, NULL);
else { /* send the ack later */
if (ackTimeout > PPTP_MAX_ACK_DELAY)
ackTimeout = PPTP_MAX_ACK_DELAY;
ng_pptpgre_start_send_ack_timer(node,
ackTimeout);
if (maxWait > PPTP_MAX_ACK_DELAY)
maxWait = PPTP_MAX_ACK_DELAY;
ng_pptpgre_start_send_ack_timer(node, maxWait);
}
}
@ -718,9 +715,8 @@ ng_pptpgre_start_recv_ack_timer(node_p node)
struct ng_pptpgre_ackp *const a = &priv->ackp;
int remain;
/* Stop current recv ack timer, if any */
if (a->rackTimerRunning)
ng_pptpgre_stop_recv_ack_timer(node);
/* "Stop" current recv ack timer, if any */
a->rackTimerPtr = NULL;
/* Are we waiting for an acknowlegement? */
if (priv->recvAck == priv->xmitSeq)
@ -732,28 +728,14 @@ ng_pptpgre_start_recv_ack_timer(node_p node)
if (remain < 0)
remain = 0;
/* Start timer */
a->rackTimer = timeout(ng_pptpgre_recv_ack_timeout,
node, remain * hz / PPTP_TIME_SCALE);
/* Start new timer */
MALLOC(a->rackTimerPtr, node_p *, sizeof(node_p), M_NETGRAPH, M_NOWAIT);
if (a->rackTimerPtr == NULL)
return; /* XXX potential hang here */
*a->rackTimerPtr = node; /* insures the correct timeout event */
node->refs++;
a->rackTimerRunning = 1;
}
/*
* Stop the recv ack timer, if running.
*/
static void
ng_pptpgre_stop_recv_ack_timer(node_p node)
{
const priv_p priv = node->private;
struct ng_pptpgre_ackp *const a = &priv->ackp;
if (a->rackTimerRunning) {
untimeout(ng_pptpgre_recv_ack_timeout, node, a->rackTimer);
KASSERT(node->refs > 1, ("%s: no refs", __FUNCTION__));
ng_unref(node);
a->rackTimerRunning = 0;
}
a->rackTimer = timeout(ng_pptpgre_recv_ack_timeout,
a->rackTimerPtr, remain * hz / PPTP_TIME_SCALE);
}
/*
@ -765,22 +747,24 @@ static void
ng_pptpgre_recv_ack_timeout(void *arg)
{
int s = splnet();
const node_p node = arg;
const node_p node = *((node_p *)arg);
const priv_p priv = node->private;
struct ng_pptpgre_ackp *const a = &priv->ackp;
/* Avoid shutdown race condition */
if ((node->flags & NG_INVALID) != 0) {
/* This complicated stuff is needed to avoid race conditions */
FREE(arg, M_NETGRAPH);
KASSERT(node->refs > 0, ("%s: no refs", __FUNCTION__));
if ((node->flags & NG_INVALID) != 0) { /* shutdown race condition */
ng_unref(node);
splx(s);
return;
}
/* Release timer reference */
KASSERT(a->rackTimerRunning, ("%s: !rackTimer", __FUNCTION__));
a->rackTimerRunning = 0;
KASSERT(node->refs > 1, ("%s: no refs", __FUNCTION__));
ng_unref(node);
if (arg != a->rackTimerPtr) { /* timer stopped race condition */
splx(s);
return;
}
a->rackTimerPtr = NULL;
/* Update adaptive timeout stuff */
priv->stats.recvAckTimeouts++;
@ -810,28 +794,15 @@ ng_pptpgre_start_send_ack_timer(node_p node, long ackTimeout)
const priv_p priv = node->private;
struct ng_pptpgre_ackp *const a = &priv->ackp;
KASSERT(!a->sackTimerRunning, ("%s: sackTimer", __FUNCTION__));
a->sackTimer = timeout(ng_pptpgre_send_ack_timeout,
node, ackTimeout * hz / PPTP_TIME_SCALE);
/* Start new timer */
KASSERT(a->sackTimerPtr == NULL, ("%s: sackTimer", __FUNCTION__));
MALLOC(a->sackTimerPtr, node_p *, sizeof(node_p), M_NETGRAPH, M_NOWAIT);
if (a->sackTimerPtr == NULL)
return; /* XXX potential hang here */
*a->sackTimerPtr = node;
node->refs++;
a->sackTimerRunning = 1;
}
/*
* Stop the send ack timer, if running.
*/
static void
ng_pptpgre_stop_send_ack_timer(node_p node)
{
const priv_p priv = node->private;
struct ng_pptpgre_ackp *const a = &priv->ackp;
if (a->sackTimerRunning) {
untimeout(ng_pptpgre_send_ack_timeout, node, a->sackTimer);
KASSERT(node->refs > 1, ("%s: no refs", __FUNCTION__));
ng_unref(node);
a->sackTimerRunning = 0;
}
a->sackTimer = timeout(ng_pptpgre_send_ack_timeout,
a->sackTimerPtr, ackTimeout * hz / PPTP_TIME_SCALE);
}
/*
@ -844,22 +815,24 @@ static void
ng_pptpgre_send_ack_timeout(void *arg)
{
int s = splnet();
const node_p node = arg;
const node_p node = *((node_p *)arg);
const priv_p priv = node->private;
struct ng_pptpgre_ackp *const a = &priv->ackp;
/* Avoid shutdown race condition */
if ((node->flags & NG_INVALID) != 0) {
/* This complicated stuff is needed to avoid race conditions */
FREE(arg, M_NETGRAPH);
KASSERT(node->refs > 0, ("%s: no refs", __FUNCTION__));
if ((node->flags & NG_INVALID) != 0) { /* shutdown race condition */
ng_unref(node);
splx(s);
return;
}
/* Release timer reference */
KASSERT(a->sackTimerRunning, ("%s: !sackTimer", __FUNCTION__));
a->sackTimerRunning = 0;
KASSERT(node->refs > 1, ("%s: no refs", __FUNCTION__));
ng_unref(node);
if (a->sackTimerPtr != arg) { /* timer stopped race condition */
splx(s);
return;
}
a->sackTimerPtr = NULL;
/* Send a frame with an ack but no payload */
ng_pptpgre_xmit(node, NULL, NULL);
@ -886,17 +859,17 @@ ng_pptpgre_reset(node_p node)
a->rtt = PPTP_MIN_RTT;
a->dev = 0;
a->xmitWin = (priv->conf.recvWin + 1) / 2;
if (a->xmitWin < 1)
a->xmitWin = 1;
if (a->xmitWin < 2)
a->xmitWin = 2;
if (a->xmitWin > PPTP_XMIT_WIN)
a->xmitWin = PPTP_XMIT_WIN;
a->winAck = a->xmitWin;
/* Reset sequence numbers */
priv->recvSeq = 0;
priv->recvAck = 0;
priv->xmitSeq = 0;
priv->xmitAck = 0;
priv->recvSeq = ~0;
priv->recvAck = ~0;
priv->xmitSeq = ~0;
priv->xmitAck = ~0;
/* Reset start time */
getmicrouptime(&priv->startTime);
@ -904,9 +877,9 @@ ng_pptpgre_reset(node_p node)
/* Reset stats */
bzero(&priv->stats, sizeof(priv->stats));
/* Stop timers */
ng_pptpgre_stop_send_ack_timer(node);
ng_pptpgre_stop_recv_ack_timer(node);
/* "Stop" timers */
a->sackTimerPtr = NULL;
a->rackTimerPtr = NULL;
}
/*