Use 'struct callout' instead of 'struct callout_handle' to avoid
exhausting the kernel timeout table. Perform the usual gymnastics to avoid race conditions between node shutdown and timeouts occurring. Also fix a bug in handling ack delays < PPTP_MIN_ACK_DELAY. Before, we were ack'ing immediately. Instead, just impose a minimum ack delay time, like the name of the macro implies. MFC after: 1 week
This commit is contained in:
parent
46e12b42fe
commit
4a48abb26a
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=94667
@ -118,7 +118,7 @@ typedef u_int64_t pptptime_t;
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/* Acknowledgment timeout parameters and functions */
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#define PPTP_XMIT_WIN 16 /* max xmit window */
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#define PPTP_MIN_RTT (PPTP_TIME_SCALE / 10) /* 100 milliseconds */
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#define PPTP_MIN_TIMEOUT (PPTP_TIME_SCALE / 500) /* 2 milliseconds */
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#define PPTP_MIN_TIMEOUT (PPTP_TIME_SCALE / 83) /* 12 milliseconds */
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#define PPTP_MAX_TIMEOUT (10 * PPTP_TIME_SCALE) /* 10 seconds */
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/* When we recieve a packet, we wait to see if there's an outgoing packet
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@ -142,8 +142,8 @@ struct ng_pptpgre_ackp {
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int32_t rtt; /* round trip time estimate */
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int32_t dev; /* deviation estimate */
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u_int16_t xmitWin; /* size of xmit window */
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struct callout_handle sackTimer; /* send ack timer */
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struct callout_handle rackTimer; /* recv ack timer */
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struct callout sackTimer; /* send ack timer */
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struct callout rackTimer; /* recv ack timer */
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node_p *sackTimerPtr; /* send ack timer pointer */
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node_p *rackTimerPtr; /* recv ack timer pointer */
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u_int32_t winAck; /* seq when xmitWin will grow */
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@ -164,6 +164,7 @@ struct ng_pptpgre_private {
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u_int32_t xmitSeq; /* last seq # we sent */
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u_int32_t recvAck; /* last seq # peer ack'd */
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u_int32_t xmitAck; /* last seq # we ack'd */
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u_int timers; /* number of pending timers */
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struct timeval startTime; /* time node was created */
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struct ng_pptpgre_stats stats; /* node statistics */
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};
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@ -181,7 +182,9 @@ static ng_disconnect_t ng_pptpgre_disconnect;
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static int ng_pptpgre_xmit(node_p node, item_p item);
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static int ng_pptpgre_recv(node_p node, item_p item);
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static void ng_pptpgre_start_send_ack_timer(node_p node, int ackTimeout);
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static void ng_pptpgre_stop_send_ack_timer(node_p node);
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static void ng_pptpgre_start_recv_ack_timer(node_p node);
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static void ng_pptpgre_stop_recv_ack_timer(node_p node);
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static void ng_pptpgre_recv_ack_timeout(void *arg);
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static void ng_pptpgre_send_ack_timeout(void *arg);
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static void ng_pptpgre_reset(node_p node);
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@ -282,8 +285,8 @@ ng_pptpgre_constructor(node_p node)
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NG_NODE_SET_PRIVATE(node, priv);
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/* Initialize state */
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callout_handle_init(&priv->ackp.sackTimer);
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callout_handle_init(&priv->ackp.rackTimer);
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callout_init(&priv->ackp.sackTimer, 0);
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callout_init(&priv->ackp.rackTimer, 0);
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/* Done */
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return (0);
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@ -413,10 +416,14 @@ ng_pptpgre_shutdown(node_p node)
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/* Reset node */
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ng_pptpgre_reset(node);
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/* Take down netgraph node */
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bzero(priv, sizeof(*priv));
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FREE(priv, M_NETGRAPH);
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NG_NODE_SET_PRIVATE(node, NULL);
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/* If no timers remain, free private info as well */
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if (priv->timers == 0) {
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bzero(priv, sizeof(*priv));
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FREE(priv, M_NETGRAPH);
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NG_NODE_SET_PRIVATE(node, NULL);
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}
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/* Decrement ref count */
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NG_NODE_UNREF(node);
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return (0);
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}
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@ -509,7 +516,7 @@ ng_pptpgre_xmit(node_p node, item_p item)
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gre->hasAck = 1;
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gre->data[gre->hasSeq] = htonl(priv->recvSeq);
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priv->xmitAck = priv->recvSeq;
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a->sackTimerPtr = NULL; /* "stop" timer */
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ng_pptpgre_stop_send_ack_timer(node);
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}
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/* Prepend GRE header to outgoing frame */
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@ -672,7 +679,7 @@ ng_pptpgre_recv(node_p node, item_p item)
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}
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/* Stop/(re)start receive ACK timer as necessary */
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a->rackTimerPtr = NULL;
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ng_pptpgre_stop_recv_ack_timer(node);
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if (priv->recvAck != priv->xmitSeq)
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ng_pptpgre_start_recv_ack_timer(node);
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}
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@ -701,10 +708,11 @@ ng_pptpgre_recv(node_p node, item_p item)
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maxWait = (a->rtt >> 2);
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/* If delayed ACK is disabled, send it now */
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if (!priv->conf.enableDelayedAck
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|| maxWait < PPTP_MIN_ACK_DELAY)
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if (!priv->conf.enableDelayedAck) /* ack now */
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ng_pptpgre_xmit(node, NULL);
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else { /* send the ack later */
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else { /* ack later */
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if (maxWait < PPTP_MIN_ACK_DELAY)
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maxWait = PPTP_MIN_ACK_DELAY;
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if (maxWait > PPTP_MAX_ACK_DELAY)
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maxWait = PPTP_MAX_ACK_DELAY;
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ng_pptpgre_start_send_ack_timer(node, maxWait);
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@ -760,13 +768,31 @@ ng_pptpgre_start_recv_ack_timer(node_p node)
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priv->stats.memoryFailures++;
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return; /* XXX potential hang here */
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}
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*a->rackTimerPtr = node; /* insures the correct timeout event */
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*a->rackTimerPtr = node; /* ensures the correct timeout event */
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NG_NODE_REF(node);
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priv->timers++;
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/* Be conservative: timeout() can return up to 1 tick early */
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/* Be conservative: timeout can happen up to 1 tick early */
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ticks = (((remain * hz) + PPTP_TIME_SCALE - 1) / PPTP_TIME_SCALE) + 1;
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a->rackTimer = timeout(ng_pptpgre_recv_ack_timeout,
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a->rackTimerPtr, ticks);
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callout_reset(&a->rackTimer, ticks,
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ng_pptpgre_recv_ack_timeout, a->rackTimerPtr);
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}
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/*
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* Stop receive ack timer.
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*/
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static void
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ng_pptpgre_stop_recv_ack_timer(node_p node)
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{
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const priv_p priv = NG_NODE_PRIVATE(node);
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struct ng_pptpgre_ackp *const a = &priv->ackp;
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if (callout_stop(&a->rackTimer)) {
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FREE(a->rackTimerPtr, M_NETGRAPH);
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priv->timers--;
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NG_NODE_UNREF(node);
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}
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a->rackTimerPtr = NULL;
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}
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/*
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@ -785,7 +811,13 @@ ng_pptpgre_recv_ack_timeout(void *arg)
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/* This complicated stuff is needed to avoid race conditions */
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FREE(arg, M_NETGRAPH);
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KASSERT(node->nd_refs > 0, ("%s: no nd_refs", __func__));
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KASSERT(priv != NULL, ("%s: priv=NULL", __func__));
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priv->timers--;
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if (NG_NODE_NOT_VALID(node)) { /* shutdown race condition */
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if (priv->timers == 0) {
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FREE(priv, M_NETGRAPH);
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NG_NODE_SET_PRIVATE(node, NULL);
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}
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NG_NODE_UNREF(node);
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splx(s);
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return;
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@ -839,13 +871,31 @@ ng_pptpgre_start_send_ack_timer(node_p node, int ackTimeout)
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priv->stats.memoryFailures++;
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return; /* XXX potential hang here */
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}
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*a->sackTimerPtr = node;
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*a->sackTimerPtr = node; /* ensures the correct timeout event */
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NG_NODE_REF(node);
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priv->timers++;
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/* Be conservative: timeout() can return up to 1 tick early */
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/* Be conservative: timeout can happen up to 1 tick early */
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ticks = (((ackTimeout * hz) + PPTP_TIME_SCALE - 1) / PPTP_TIME_SCALE);
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a->sackTimer = timeout(ng_pptpgre_send_ack_timeout,
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a->sackTimerPtr, ticks);
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callout_reset(&a->sackTimer, ticks,
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ng_pptpgre_send_ack_timeout, a->sackTimerPtr);
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}
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/*
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* Stop send ack timer.
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*/
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static void
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ng_pptpgre_stop_send_ack_timer(node_p node)
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{
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const priv_p priv = NG_NODE_PRIVATE(node);
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struct ng_pptpgre_ackp *const a = &priv->ackp;
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if (callout_stop(&a->sackTimer)) {
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FREE(a->sackTimerPtr, M_NETGRAPH);
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priv->timers--;
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NG_NODE_UNREF(node);
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}
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a->sackTimerPtr = NULL;
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}
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/*
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@ -865,7 +915,13 @@ ng_pptpgre_send_ack_timeout(void *arg)
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/* This complicated stuff is needed to avoid race conditions */
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FREE(arg, M_NETGRAPH);
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KASSERT(node->nd_refs > 0, ("%s: no nd_refs", __func__));
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KASSERT(priv != NULL, ("%s: priv=NULL", __func__));
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priv->timers--;
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if (NG_NODE_NOT_VALID(node)) { /* shutdown race condition */
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if (priv->timers == 0) {
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FREE(priv, M_NETGRAPH);
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NG_NODE_SET_PRIVATE(node, NULL);
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}
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NG_NODE_UNREF(node);
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splx(s);
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return;
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@ -921,9 +977,9 @@ ng_pptpgre_reset(node_p node)
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/* Reset stats */
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bzero(&priv->stats, sizeof(priv->stats));
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/* "Stop" timers */
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a->sackTimerPtr = NULL;
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a->rackTimerPtr = NULL;
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/* Stop timers */
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ng_pptpgre_stop_send_ack_timer(node);
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ng_pptpgre_stop_recv_ack_timer(node);
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}
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/*
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