Several fixes:
- Fix slowness when operating over fast connections, where the timeout(9) granularity is on the same order of magnitude as the round trip time. timeout(9) can happen up to 1 tick early, which was causing receive ack timeouts to happen too early, causing bogus "lost" packets. - Increase the local time counter to 64 bits to avoid roll-over. - Keep statistics on memory allocation failures. - Add a new option to always include the ack when sending data packets. Might be useful in high packet loss situations. Might not.
This commit is contained in:
Archie Cobbs
parent
c27eebfde8
commit
678f9e335e
@ -116,7 +116,7 @@ struct greheader {
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/* All times are scaled by this (PPTP_TIME_SCALE time units = 1 sec.) */
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#define PPTP_TIME_SCALE 1000 /* milliseconds */
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typedef u_int32_t pptptime_t;
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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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@ -144,6 +144,10 @@ struct ng_pptpgre_ackp {
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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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pptptime_t timeSent[PPTP_XMIT_WIN];
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#ifdef DEBUG_RAT
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pptptime_t timerStart;
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pptptime_t timerLength;
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#endif
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};
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/* When we recieve a packet, we wait to see if there's an outgoing packet
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@ -493,7 +497,7 @@ ng_pptpgre_xmit(node_p node, struct mbuf *m, meta_p meta)
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priv->stats.xmitLoneAcks++;
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/* Build GRE header */
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((u_int32_t *) gre)[0] = htonl(PPTP_INIT_VALUE);
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((u_int32_t *)gre)[0] = htonl(PPTP_INIT_VALUE);
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gre->length = (m != NULL) ? htons((u_short)m->m_pkthdr.len) : 0;
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gre->cid = htons(priv->conf.peerCid);
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@ -504,15 +508,13 @@ ng_pptpgre_xmit(node_p node, struct mbuf *m, meta_p meta)
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= ng_pptpgre_time(node);
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priv->xmitSeq++;
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gre->data[0] = htonl(priv->xmitSeq);
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if (priv->xmitSeq == priv->recvAck + 1)
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ng_pptpgre_start_recv_ack_timer(node);
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}
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/* Include acknowledgement (and stop send ack timer) if needed */
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if (PPTP_SEQ_DIFF(priv->xmitAck, priv->recvSeq) < 0) {
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if (priv->conf.enableAlwaysAck || priv->xmitAck != priv->recvSeq) {
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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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gre->data[gre->hasSeq] = htonl(priv->xmitAck);
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a->sackTimerPtr = NULL;
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}
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@ -521,6 +523,7 @@ ng_pptpgre_xmit(node_p node, struct mbuf *m, meta_p meta)
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if (m == NULL) {
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MGETHDR(m, M_DONTWAIT, MT_DATA);
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if (m == NULL) {
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priv->stats.memoryFailures++;
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NG_FREE_META(meta);
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return (ENOBUFS);
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}
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@ -530,6 +533,7 @@ ng_pptpgre_xmit(node_p node, struct mbuf *m, meta_p meta)
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M_PREPEND(m, grelen, M_NOWAIT);
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if (m == NULL || (m->m_len < grelen
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&& (m = m_pullup(m, grelen)) == NULL)) {
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priv->stats.memoryFailures++;
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NG_FREE_META(meta);
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return (ENOBUFS);
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}
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@ -542,6 +546,10 @@ ng_pptpgre_xmit(node_p node, struct mbuf *m, meta_p meta)
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/* Deliver packet */
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NG_SEND_DATA(error, priv->lower, m, meta);
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/* Start send ACK timer */
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if (error == 0 && gre->hasSeq && priv->xmitSeq == priv->recvAck + 1)
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ng_pptpgre_start_recv_ack_timer(node);
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return (error);
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}
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@ -572,6 +580,7 @@ bad:
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/* Safely pull up the complete IP+GRE headers */
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if (m->m_len < sizeof(*ip) + sizeof(*gre)
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&& (m = m_pullup(m, sizeof(*ip) + sizeof(*gre))) == NULL) {
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priv->stats.memoryFailures++;
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NG_FREE_META(meta);
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return (ENOBUFS);
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}
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@ -579,6 +588,7 @@ bad:
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iphlen = ip->ip_hl << 2;
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if (m->m_len < iphlen + sizeof(*gre)) {
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if ((m = m_pullup(m, iphlen + sizeof(*gre))) == NULL) {
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priv->stats.memoryFailures++;
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NG_FREE_META(meta);
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return (ENOBUFS);
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}
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@ -592,6 +602,7 @@ bad:
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}
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if (m->m_len < iphlen + grelen) {
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if ((m = m_pullup(m, iphlen + grelen)) == NULL) {
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priv->stats.memoryFailures++;
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NG_FREE_META(meta);
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return (ENOBUFS);
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}
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@ -656,7 +667,9 @@ bad:
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}
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/* Stop/(re)start receive ACK timer as necessary */
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ng_pptpgre_start_recv_ack_timer(node);
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a->rackTimerPtr = NULL;
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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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badAck:
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@ -682,8 +695,8 @@ badAck:
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/* Take half of the estimated round trip time */
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maxWait = (a->rtt >> 1);
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/* If too soon, just send one right now */
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if (!priv->conf.enableDelayedAck)
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/* If delayed ACK is disabled, send it now */
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if (!priv->conf.enableDelayedAck || maxWait == 0)
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ng_pptpgre_xmit(node, NULL, NULL);
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else { /* send the ack later */
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if (maxWait > PPTP_MAX_ACK_DELAY)
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@ -721,29 +734,31 @@ ng_pptpgre_start_recv_ack_timer(node_p node)
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{
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const priv_p priv = node->private;
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struct ng_pptpgre_ackp *const a = &priv->ackp;
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int remain;
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/* "Stop" current recv ack timer, if any */
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a->rackTimerPtr = NULL;
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/* Are we waiting for an acknowlegement? */
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if (priv->recvAck == priv->xmitSeq)
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return;
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int remain, ticks;
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/* Compute how long until oldest unack'd packet times out,
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and reset the timer to that time. */
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remain = (a->timeSent[0] + a->ato) - ng_pptpgre_time(node);
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if (remain < 0)
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remain = 0;
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#ifdef DEBUG_RAT
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a->timerLength = remain;
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a->timerStart = ng_pptpgre_time(node);
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#endif
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/* Start new timer */
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MALLOC(a->rackTimerPtr, node_p *, sizeof(node_p), M_NETGRAPH, M_NOWAIT);
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if (a->rackTimerPtr == NULL)
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if (a->rackTimerPtr == NULL) {
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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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node->refs++;
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/* Be conservative: timeout() can return 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, remain * hz / PPTP_TIME_SCALE);
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a->rackTimerPtr, ticks);
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}
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/*
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@ -783,6 +798,13 @@ ng_pptpgre_recv_ack_timeout(void *arg)
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if (a->ato < PPTP_MIN_TIMEOUT)
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a->ato = PPTP_MIN_TIMEOUT;
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#ifdef DEBUG_RAT
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log(LOG_DEBUG,
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"RAT now=%d seq=0x%x sent=%d tstart=%d tlen=%d ato=%d\n",
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(int)ng_pptpgre_time(node), priv->recvAck + 1,
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(int)a->timeSent[0], (int)a->timerStart, (int)a->timerLength, a->ato);
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#endif
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/* Reset ack and sliding window */
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priv->recvAck = priv->xmitSeq; /* pretend we got the ack */
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a->xmitWin = (a->xmitWin + 1) / 2; /* shrink transmit window */
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@ -799,16 +821,22 @@ ng_pptpgre_start_send_ack_timer(node_p node, long ackTimeout)
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{
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const priv_p priv = node->private;
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struct ng_pptpgre_ackp *const a = &priv->ackp;
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int ticks;
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/* Start new timer */
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KASSERT(a->sackTimerPtr == NULL, ("%s: sackTimer", __FUNCTION__));
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MALLOC(a->sackTimerPtr, node_p *, sizeof(node_p), M_NETGRAPH, M_NOWAIT);
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if (a->sackTimerPtr == NULL)
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if (a->sackTimerPtr == NULL) {
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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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node->refs++;
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/* Be conservative: timeout() can return 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, ackTimeout * hz / PPTP_TIME_SCALE);
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a->sackTimerPtr, ticks);
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}
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/*
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@ -896,15 +924,16 @@ ng_pptpgre_time(node_p node)
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{
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const priv_p priv = node->private;
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struct timeval tv;
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pptptime_t t;
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getmicrouptime(&tv);
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microuptime(&tv);
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if (tv.tv_sec < priv->startTime.tv_sec
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|| (tv.tv_sec == priv->startTime.tv_sec
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&& tv.tv_usec < priv->startTime.tv_usec))
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return (0);
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timevalsub(&tv, &priv->startTime);
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tv.tv_sec *= PPTP_TIME_SCALE;
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tv.tv_usec /= 1000000 / PPTP_TIME_SCALE;
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return(tv.tv_sec + tv.tv_usec);
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t = (pptptime_t)tv.tv_sec * PPTP_TIME_SCALE;
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t += (pptptime_t)tv.tv_usec / (1000000 / PPTP_TIME_SCALE);
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return(t);
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}
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@ -45,7 +45,7 @@
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/* Node type name and magic cookie */
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#define NG_PPTPGRE_NODE_TYPE "pptpgre"
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#define NGM_PPTPGRE_COOKIE 942783546
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#define NGM_PPTPGRE_COOKIE 942783547
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/* Hook names */
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#define NG_PPTPGRE_HOOK_UPPER "upper" /* to upper layers */
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@ -55,6 +55,7 @@
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struct ng_pptpgre_conf {
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u_char enabled; /* enables traffic flow */
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u_char enableDelayedAck;/* enables delayed acks */
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u_char enableAlwaysAck;/* always include ack with data */
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u_int16_t cid; /* my call id */
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u_int16_t peerCid; /* peer call id */
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u_int16_t recvWin; /* peer recv window size */
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@ -67,6 +68,7 @@ struct ng_pptpgre_conf {
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{ \
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{ "enabled", &ng_parse_int8_type }, \
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{ "enableDelayedAck", &ng_parse_int8_type }, \
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{ "enableAlwaysAck", &ng_parse_int8_type }, \
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{ "cid", &ng_parse_int16_type }, \
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{ "peerCid", &ng_parse_int16_type }, \
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{ "recvWin", &ng_parse_int16_type }, \
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@ -92,6 +94,7 @@ struct ng_pptpgre_stats {
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u_int32_t recvDuplicates; /* packets rec'd with duplicate seq # */
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u_int32_t recvLoneAcks; /* ack-only packets rec'd */
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u_int32_t recvAckTimeouts; /* times peer failed to ack in time */
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u_int32_t memoryFailures; /* times we couldn't allocate memory */
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};
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/* Keep this in sync with the above structure definition */
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@ -112,6 +115,7 @@ struct ng_pptpgre_stats {
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{ "recvDuplicates", &ng_parse_int32_type }, \
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{ "recvLoneAcks", &ng_parse_int32_type }, \
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{ "recvAckTimeouts", &ng_parse_int32_type }, \
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{ "memoryFailures", &ng_parse_int32_type }, \
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{ NULL } \
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} \
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}
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