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freebsd/sys/netgraph/ng_pptpgre.c
Archie Cobbs 9bee7adfa8 Fix a couple of bugs: 
- Properly handle 32 bit sequence numbers when they wrap around
- Don't drop GRE packets with stale ACK numbers, just ignore the ACK
- Close race between node being shutdown and timer going off
Also add support for lots of statistics, and control message ASCIIfication
2000-05-05 01:11:39 +00:00

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/*
* ng_pptpgre.c
*
* Copyright (c) 1996-1999 Whistle Communications, Inc.
* All rights reserved.
*
* Subject to the following obligations and disclaimer of warranty, use and
* redistribution of this software, in source or object code forms, with or
* without modifications are expressly permitted by Whistle Communications;
* provided, however, that:
* 1. Any and all reproductions of the source or object code must include the
* copyright notice above and the following disclaimer of warranties; and
* 2. No rights are granted, in any manner or form, to use Whistle
* Communications, Inc. trademarks, including the mark "WHISTLE
* COMMUNICATIONS" on advertising, endorsements, or otherwise except as
* such appears in the above copyright notice or in the software.
*
* THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
* TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
* REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
* INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
* WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
* REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
* SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
* IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
* RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
* WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
* PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
* OF SUCH DAMAGE.
*
* Author: Archie Cobbs <archie@whistle.com>
*
* $FreeBSD$
* $Whistle: ng_pptpgre.c,v 1.7 1999/12/08 00:10:06 archie Exp $
*/
/*
* PPTP/GRE netgraph node type.
*
* This node type does the GRE encapsulation as specified for the PPTP
* protocol (RFC 2637, section 4). This includes sequencing and
* retransmission of frames, but not the actual packet delivery nor
* any of the TCP control stream protocol.
*
* The "upper" hook of this node is suitable for attaching to a "ppp"
* node link hook. The "lower" hook of this node is suitable for attaching
* to a "ksocket" node on hook "inet/raw/gre".
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/time.h>
#include <sys/mbuf.h>
#include <sys/malloc.h>
#include <sys/errno.h>
#include <sys/socket.h>
#include <sys/syslog.h>
#include <sys/ctype.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netgraph/ng_message.h>
#include <netgraph/netgraph.h>
#include <netgraph/ng_parse.h>
#include <netgraph/ng_pptpgre.h>
/* GRE packet format, as used by PPTP */
struct greheader {
#if BYTE_ORDER == LITTLE_ENDIAN
u_char recursion:3; /* recursion control */
u_char ssr:1; /* strict source route */
u_char hasSeq:1; /* sequence number present */
u_char hasKey:1; /* key present */
u_char hasRoute:1; /* routing present */
u_char hasSum:1; /* checksum present */
u_char vers:3; /* version */
u_char flags:4; /* flags */
u_char hasAck:1; /* acknowlege number present */
#elif BYTE_ORDER == BIG_ENDIAN
u_char hasSum:1; /* checksum present */
u_char hasRoute:1; /* routing present */
u_char hasKey:1; /* key present */
u_char hasSeq:1; /* sequence number present */
u_char ssr:1; /* strict source route */
u_char recursion:3; /* recursion control */
u_char hasAck:1; /* acknowlege number present */
u_char flags:4; /* flags */
u_char vers:3; /* version */
#else
#error BYTE_ORDER is not defined properly
#endif
u_int16_t proto; /* protocol (ethertype) */
u_int16_t length; /* payload length */
u_int16_t cid; /* call id */
u_int32_t data[0]; /* opt. seq, ack, then data */
};
/* The PPTP protocol ID used in the GRE 'proto' field */
#define PPTP_GRE_PROTO 0x880b
/* Bits that must be set a certain way in all PPTP/GRE packets */
#define PPTP_INIT_VALUE ((0x2001 << 16) | PPTP_GRE_PROTO)
#define PPTP_INIT_MASK 0xef7fffff
/* Min and max packet length */
#define PPTP_MAX_PAYLOAD (0xffff - sizeof(struct greheader) - 8)
/* All times are scaled by this (PPTP_TIME_SCALE time units = 1 sec.) */
#define PPTP_TIME_SCALE 1000
typedef u_int32_t pptptime_t;
/* Acknowledgment timeout parameters and functions */
#define PPTP_XMIT_WIN 8 /* max xmit window */
#define PPTP_MIN_RTT (PPTP_TIME_SCALE / 10) /* 1/10 second */
#define PPTP_MAX_TIMEOUT (10 * PPTP_TIME_SCALE) /* 10 seconds */
#define PPTP_ACK_ALPHA(x) ((x) >> 3) /* alpha = 0.125 */
#define PPTP_ACK_BETA(x) ((x) >> 2) /* beta = 0.25 */
#define PPTP_ACK_CHI(x) ((x) << 2) /* chi = 4 */
#define PPTP_ACK_DELTA(x) ((x) << 1) /* delta = 2 */
#define PPTP_SEQ_DIFF(x,y) ((int32_t)(x) - (int32_t)(y))
/* We keep packet retransmit and acknowlegement state in this struct */
struct ng_pptpgre_ackp {
int32_t ato; /* adaptive time-out value */
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 */
pptptime_t timeSent[PPTP_XMIT_WIN];
};
/* When we recieve a packet, we wait to see if there's an outgoing packet
we can piggy-back the ACK off of. These parameters determine the mimimum
and maxmimum length of time we're willing to wait in order to do that. */
#define PPTP_MAX_ACK_DELAY ((int) (0.25 * PPTP_TIME_SCALE))
/* Node private data */
struct ng_pptpgre_private {
hook_p upper; /* hook to upper layers */
hook_p lower; /* hook to lower layers */
struct ng_pptpgre_conf conf; /* configuration info */
struct ng_pptpgre_ackp ackp; /* packet transmit ack state */
u_int32_t recvSeq; /* last seq # we rcv'd */
u_int32_t xmitSeq; /* last seq # we sent */
u_int32_t recvAck; /* last seq # peer ack'd */
u_int32_t xmitAck; /* last seq # we ack'd */
struct timeval startTime; /* time node was created */
struct ng_pptpgre_stats stats; /* node statistics */
};
typedef struct ng_pptpgre_private *priv_p;
/* Netgraph node methods */
static ng_constructor_t ng_pptpgre_constructor;
static ng_rcvmsg_t ng_pptpgre_rcvmsg;
static ng_shutdown_t ng_pptpgre_rmnode;
static ng_newhook_t ng_pptpgre_newhook;
static ng_rcvdata_t ng_pptpgre_rcvdata;
static ng_disconnect_t ng_pptpgre_disconnect;
/* Helper functions */
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);
static pptptime_t ng_pptpgre_time(node_p node);
/* Parse type for struct ng_pptpgre_conf */
static const struct ng_parse_struct_info
ng_pptpgre_conf_type_info = NG_PPTPGRE_CONF_TYPE_INFO;
static const struct ng_parse_type ng_pptpgre_conf_type = {
&ng_parse_struct_type,
&ng_pptpgre_conf_type_info,
};
/* Parse type for struct ng_pptpgre_stats */
static const struct ng_parse_struct_info
ng_pptpgre_stats_type_info = NG_PPTPGRE_STATS_TYPE_INFO;
static const struct ng_parse_type ng_pptp_stats_type = {
&ng_parse_struct_type,
&ng_pptpgre_stats_type_info
};
/* List of commands and how to convert arguments to/from ASCII */
static const struct ng_cmdlist ng_pptpgre_cmdlist[] = {
{
NGM_PPTPGRE_COOKIE,
NGM_PPTPGRE_SET_CONFIG,
"setconfig",
&ng_pptpgre_conf_type,
NULL
},
{
NGM_PPTPGRE_COOKIE,
NGM_PPTPGRE_GET_CONFIG,
"getconfig",
NULL,
&ng_pptpgre_conf_type
},
{
NGM_PPTPGRE_COOKIE,
NGM_PPTPGRE_GET_STATS,
"getstats",
NULL,
&ng_pptp_stats_type
},
{
NGM_PPTPGRE_COOKIE,
NGM_PPTPGRE_CLR_STATS,
"clrstats",
NULL,
NULL
},
{
NGM_PPTPGRE_COOKIE,
NGM_PPTPGRE_GETCLR_STATS,
"getclrstats",
NULL,
&ng_pptp_stats_type
},
{ 0 }
};
/* Node type descriptor */
static struct ng_type ng_pptpgre_typestruct = {
NG_VERSION,
NG_PPTPGRE_NODE_TYPE,
NULL,
ng_pptpgre_constructor,
ng_pptpgre_rcvmsg,
ng_pptpgre_rmnode,
ng_pptpgre_newhook,
NULL,
NULL,
ng_pptpgre_rcvdata,
ng_pptpgre_rcvdata,
ng_pptpgre_disconnect,
ng_pptpgre_cmdlist
};
NETGRAPH_INIT(pptpgre, &ng_pptpgre_typestruct);
#define ERROUT(x) do { error = (x); goto done; } while (0)
/************************************************************************
NETGRAPH NODE STUFF
************************************************************************/
/*
* Node type constructor
*/
static int
ng_pptpgre_constructor(node_p *nodep)
{
priv_p priv;
int error;
/* Allocate private structure */
MALLOC(priv, priv_p, sizeof(*priv), M_NETGRAPH, M_WAITOK);
if (priv == NULL)
return (ENOMEM);
bzero(priv, sizeof(*priv));
/* Call generic node constructor */
if ((error = ng_make_node_common(&ng_pptpgre_typestruct, nodep))) {
FREE(priv, M_NETGRAPH);
return (error);
}
(*nodep)->private = priv;
/* Initialize state */
callout_handle_init(&priv->ackp.sackTimer);
callout_handle_init(&priv->ackp.rackTimer);
/* Done */
return (0);
}
/*
* Give our OK for a hook to be added.
*/
static int
ng_pptpgre_newhook(node_p node, hook_p hook, const char *name)
{
const priv_p priv = node->private;
hook_p *hookPtr;
/* Check hook name */
if (strcmp(name, NG_PPTPGRE_HOOK_UPPER) == 0)
hookPtr = &priv->upper;
else if (strcmp(name, NG_PPTPGRE_HOOK_LOWER) == 0)
hookPtr = &priv->lower;
else
return (EINVAL);
/* See if already connected */
if (*hookPtr != NULL)
return (EISCONN);
/* OK */
*hookPtr = hook;
return (0);
}
/*
* Receive a control message.
*/
static int
ng_pptpgre_rcvmsg(node_p node, struct ng_mesg *msg,
const char *raddr, struct ng_mesg **rptr, hook_p lasthook)
{
const priv_p priv = node->private;
struct ng_mesg *resp = NULL;
int error = 0;
switch (msg->header.typecookie) {
case NGM_PPTPGRE_COOKIE:
switch (msg->header.cmd) {
case NGM_PPTPGRE_SET_CONFIG:
{
struct ng_pptpgre_conf *const newConf =
(struct ng_pptpgre_conf *) msg->data;
/* Check for invalid or illegal config */
if (msg->header.arglen != sizeof(*newConf))
ERROUT(EINVAL);
ng_pptpgre_reset(node); /* reset on configure */
priv->conf = *newConf;
break;
}
case NGM_PPTPGRE_GET_CONFIG:
NG_MKRESPONSE(resp, msg, sizeof(priv->conf), M_NOWAIT);
if (resp == NULL)
ERROUT(ENOMEM);
bcopy(&priv->conf, resp->data, sizeof(priv->conf));
break;
case NGM_PPTPGRE_GET_STATS:
case NGM_PPTPGRE_CLR_STATS:
case NGM_PPTPGRE_GETCLR_STATS:
{
if (msg->header.cmd != NGM_PPTPGRE_CLR_STATS) {
NG_MKRESPONSE(resp, msg,
sizeof(priv->stats), M_NOWAIT);
if (resp == NULL)
ERROUT(ENOMEM);
bcopy(&priv->stats,
resp->data, sizeof(priv->stats));
}
if (msg->header.cmd != NGM_PPTPGRE_GET_STATS)
bzero(&priv->stats, sizeof(priv->stats));
break;
}
default:
error = EINVAL;
break;
}
break;
default:
error = EINVAL;
break;
}
if (rptr)
*rptr = resp;
else if (resp)
FREE(resp, M_NETGRAPH);
done:
FREE(msg, M_NETGRAPH);
return (error);
}
/*
* Receive incoming data on a hook.
*/
static int
ng_pptpgre_rcvdata(hook_p hook, struct mbuf *m, meta_p meta,
struct mbuf **ret_m, meta_p *ret_meta)
{
const node_p node = hook->node;
const priv_p priv = node->private;
/* If not configured, reject */
if (!priv->conf.enabled) {
NG_FREE_DATA(m, meta);
return (ENXIO);
}
/* Treat as xmit or recv data */
if (hook == priv->upper)
return ng_pptpgre_xmit(node, m, meta);
if (hook == priv->lower)
return ng_pptpgre_recv(node, m, meta);
panic("%s: weird hook", __FUNCTION__);
}
/*
* Destroy node
*/
static int
ng_pptpgre_rmnode(node_p node)
{
const priv_p priv = node->private;
/* Cancel timers */
ng_pptpgre_reset(node);
/* Take down netgraph node */
node->flags |= NG_INVALID;
ng_cutlinks(node);
ng_unname(node);
bzero(priv, sizeof(*priv));
FREE(priv, M_NETGRAPH);
node->private = NULL;
ng_unref(node);
return (0);
}
/*
* Hook disconnection
*/
static int
ng_pptpgre_disconnect(hook_p hook)
{
const node_p node = hook->node;
const priv_p priv = node->private;
/* Zero out hook pointer */
if (hook == priv->upper)
priv->upper = NULL;
else if (hook == priv->lower)
priv->lower = NULL;
else
panic("%s: unknown hook", __FUNCTION__);
/* Go away if no longer connected to anything */
if (node->numhooks == 0)
ng_rmnode(node);
return (0);
}
/*************************************************************************
TRANSMIT AND RECEIVE FUNCTIONS
*************************************************************************/
/*
* Transmit an outgoing frame, or just an ack if m is NULL.
*/
static int
ng_pptpgre_xmit(node_p node, struct mbuf *m, meta_p meta)
{
const priv_p priv = node->private;
struct ng_pptpgre_ackp *const a = &priv->ackp;
u_char buf[sizeof(struct greheader) + 2 * sizeof(u_int32_t)];
struct greheader *const gre = (struct greheader *)buf;
int grelen, error;
/* Check if there's data */
if (m != NULL) {
/* Is our transmit window full? */
if ((u_int32_t)PPTP_SEQ_DIFF(priv->xmitSeq, priv->recvAck)
>= a->xmitWin) {
priv->stats.xmitDrops++;
NG_FREE_DATA(m, meta);
return (ENOBUFS);
}
/* Sanity check frame length */
if (m != NULL && m->m_pkthdr.len > PPTP_MAX_PAYLOAD) {
priv->stats.xmitTooBig++;
NG_FREE_DATA(m, meta);
return (EMSGSIZE);
}
} else
priv->stats.xmitLoneAcks++;
/* Build GRE header */
((u_int32_t *) gre)[0] = htonl(PPTP_INIT_VALUE);
gre->length = (m != NULL) ? htons((u_short)m->m_pkthdr.len) : 0;
gre->cid = htons(priv->conf.peerCid);
/* Include sequence number if packet contains any data */
if (m != NULL) {
gre->hasSeq = 1;
a->timeSent[priv->xmitSeq - priv->recvAck]
= ng_pptpgre_time(node);
priv->xmitSeq++;
gre->data[0] = htonl(priv->xmitSeq);
if (priv->xmitSeq == priv->recvAck + 1)
ng_pptpgre_start_recv_ack_timer(node);
}
/* Include acknowledgement (and stop send ack timer) if needed */
if (PPTP_SEQ_DIFF(priv->xmitAck, priv->recvSeq) < 0) {
gre->hasAck = 1;
priv->xmitAck = priv->recvSeq;
gre->data[gre->hasSeq] = htonl(priv->xmitAck);
ng_pptpgre_stop_send_ack_timer(node);
}
/* Prepend GRE header to outgoing frame */
grelen = sizeof(*gre) + sizeof(u_int32_t) * (gre->hasSeq + gre->hasAck);
if (m == NULL) {
MGETHDR(m, M_DONTWAIT, MT_DATA);
if (m == NULL) {
NG_FREE_META(meta);
return (ENOBUFS);
}
m->m_len = m->m_pkthdr.len = grelen;
m->m_pkthdr.rcvif = NULL;
} else {
M_PREPEND(m, grelen, M_NOWAIT);
if (m == NULL || (m->m_len < grelen
&& (m = m_pullup(m, grelen)) == NULL)) {
NG_FREE_META(meta);
return (ENOBUFS);
}
}
bcopy(gre, mtod(m, u_char *), grelen);
/* Update stats */
priv->stats.xmitPackets++;
priv->stats.xmitOctets += m->m_pkthdr.len;
/* Deliver packet */
NG_SEND_DATA(error, priv->lower, m, meta);
return (error);
}
/*
* Handle an incoming packet. The packet includes the IP header.
*/
static int
ng_pptpgre_recv(node_p node, struct mbuf *m, meta_p meta)
{
const priv_p priv = node->private;
int iphlen, grelen, extralen;
struct greheader *gre;
struct ip *ip;
int error = 0;
/* Update stats */
priv->stats.recvPackets++;
priv->stats.recvOctets += m->m_pkthdr.len;
/* Sanity check packet length */
if (m->m_pkthdr.len < sizeof(*ip) + sizeof(*gre)) {
priv->stats.recvRunts++;
bad:
NG_FREE_DATA(m, meta);
return (EINVAL);
}
/* Safely pull up the complete IP+GRE headers */
if (m->m_len < sizeof(*ip) + sizeof(*gre)
&& (m = m_pullup(m, sizeof(*ip) + sizeof(*gre))) == NULL) {
NG_FREE_META(meta);
return (ENOBUFS);
}
ip = mtod(m, struct ip *);
iphlen = ip->ip_hl << 2;
if (m->m_len < iphlen + sizeof(*gre)) {
if ((m = m_pullup(m, iphlen + sizeof(*gre))) == NULL) {
NG_FREE_META(meta);
return (ENOBUFS);
}
ip = mtod(m, struct ip *);
}
gre = (struct greheader *)((u_char *)ip + iphlen);
grelen = sizeof(*gre) + sizeof(u_int32_t) * (gre->hasSeq + gre->hasAck);
if (m->m_pkthdr.len < iphlen + grelen) {
priv->stats.recvRunts++;
goto bad;
}
if (m->m_len < iphlen + grelen) {
if ((m = m_pullup(m, iphlen + grelen)) == NULL) {
NG_FREE_META(meta);
return (ENOBUFS);
}
ip = mtod(m, struct ip *);
gre = (struct greheader *)((u_char *)ip + iphlen);
}
/* Sanity check packet length and GRE header bits */
extralen = m->m_pkthdr.len
- (iphlen + grelen + (u_int16_t)ntohs(gre->length));
if (extralen < 0) {
priv->stats.recvBadGRE++;
goto bad;
}
if ((ntohl(*((u_int32_t *)gre)) & PPTP_INIT_MASK) != PPTP_INIT_VALUE) {
priv->stats.recvBadGRE++;
goto bad;
}
if (ntohs(gre->cid) != priv->conf.cid) {
priv->stats.recvBadCID++;
goto bad;
}
/* Look for peer ack */
if (gre->hasAck) {
struct ng_pptpgre_ackp *const a = &priv->ackp;
const u_int32_t ack = ntohl(gre->data[gre->hasSeq]);
const int index = ack - priv->recvAck - 1;
const long sample = ng_pptpgre_time(node) - a->timeSent[index];
long diff;
/* Sanity check ack value */
if (PPTP_SEQ_DIFF(ack, priv->xmitSeq) > 0) {
priv->stats.recvBadAcks++;
goto badAck; /* we never sent it! */
}
if (PPTP_SEQ_DIFF(ack, priv->recvAck) <= 0)
goto badAck; /* ack already timed out */
priv->recvAck = ack;
/* Update adaptive timeout stuff */
diff = sample - a->rtt;
a->rtt += PPTP_ACK_ALPHA(diff);
if (diff < 0)
diff = -diff;
a->dev += PPTP_ACK_BETA(diff - a->dev);
a->ato = a->rtt + (u_int) (PPTP_ACK_CHI(a->dev));
if (a->ato > PPTP_MAX_TIMEOUT)
a->ato = PPTP_MAX_TIMEOUT;
ovbcopy(a->timeSent + index + 1, a->timeSent,
sizeof(*a->timeSent) * (PPTP_XMIT_WIN - (index + 1)));
if (PPTP_SEQ_DIFF(ack, a->winAck) >= 0
&& a->xmitWin < PPTP_XMIT_WIN) {
a->xmitWin++;
a->winAck = ack + a->xmitWin;
}
/* Stop/(re)start receive ACK timer as necessary */
ng_pptpgre_start_recv_ack_timer(node);
}
badAck:
/* See if frame contains any data */
if (gre->hasSeq) {
struct ng_pptpgre_ackp *const a = &priv->ackp;
const u_int32_t seq = ntohl(gre->data[0]);
/* Sanity check sequence number */
if (PPTP_SEQ_DIFF(seq, priv->recvSeq) <= 0) {
if (seq == priv->recvSeq)
priv->stats.recvDuplicates++;
else
priv->stats.recvOutOfOrder++;
goto bad; /* out-of-order or dup */
}
priv->recvSeq = seq;
/* We need to acknowledge this packet; do it soon... */
if (!a->sackTimerRunning) {
long ackTimeout;
/* Take half of the estimated round trip time */
ackTimeout = (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);
}
}
/* Trim mbuf down to internal payload */
m_adj(m, iphlen + grelen);
if (extralen > 0)
m_adj(m, -extralen);
/* Deliver frame to upper layers */
NG_SEND_DATA(error, priv->upper, m, meta);
} else {
priv->stats.recvLoneAcks++;
NG_FREE_DATA(m, meta); /* no data to deliver */
}
return (error);
}
/*************************************************************************
TIMER RELATED FUNCTIONS
*************************************************************************/
/*
* Start a timer for the peer's acknowledging our oldest unacknowledged
* sequence number. If we get an ack for this sequence number before
* the timer goes off, we cancel the timer. Resets currently running
* recv ack timer, if any.
*/
static void
ng_pptpgre_start_recv_ack_timer(node_p node)
{
const priv_p priv = node->private;
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);
/* Are we waiting for an acknowlegement? */
if (priv->recvAck == priv->xmitSeq)
return;
/* Compute how long until oldest unack'd packet times out,
and reset the timer to that time. */
remain = (a->timeSent[0] + a->ato) - ng_pptpgre_time(node);
if (remain < 0)
remain = 0;
/* Start timer */
a->rackTimer = timeout(ng_pptpgre_recv_ack_timeout,
node, remain * hz / PPTP_TIME_SCALE);
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;
}
}
/*
* The peer has failed to acknowledge the oldest unacknowledged sequence
* number within the time allotted. Update our adaptive timeout parameters
* and reset/restart the recv ack timer.
*/
static void
ng_pptpgre_recv_ack_timeout(void *arg)
{
int s = splnet();
const node_p node = 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) {
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);
/* Update adaptive timeout stuff */
priv->stats.recvAckTimeouts++;
a->rtt = PPTP_ACK_DELTA(a->rtt);
a->ato = a->rtt + PPTP_ACK_CHI(a->dev);
if (a->ato > PPTP_MAX_TIMEOUT)
a->ato = PPTP_MAX_TIMEOUT;
priv->recvAck++; /* assume packet was lost */
a->winAck = priv->recvAck + a->xmitWin; /* reset win expand time */
ovbcopy(a->timeSent + 1, a->timeSent, /* shift xmit window times */
sizeof(*a->timeSent) * (PPTP_XMIT_WIN - 1));
a->xmitWin = (a->xmitWin + 1) / 2; /* shrink transmit window */
/* Restart timer if there are any more outstanding frames */
if (priv->recvAck != priv->xmitSeq)
ng_pptpgre_start_recv_ack_timer(node);
splx(s);
}
/*
* Start the send ack timer. This assumes the timer is not
* already running.
*/
static void
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);
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;
}
}
/*
* We've waited as long as we're willing to wait before sending an
* acknowledgement to the peer for received frames. We had hoped to
* be able to piggy back our acknowledgement on an outgoing data frame,
* but apparently there haven't been any since. So send the ack now.
*/
static void
ng_pptpgre_send_ack_timeout(void *arg)
{
int s = splnet();
const node_p node = 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) {
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);
/* Send a frame with an ack but no payload */
ng_pptpgre_xmit(node, NULL, NULL);
splx(s);
}
/*************************************************************************
MISC FUNCTIONS
*************************************************************************/
/*
* Reset state
*/
static void
ng_pptpgre_reset(node_p node)
{
const priv_p priv = node->private;
struct ng_pptpgre_ackp *const a = &priv->ackp;
/* Reset adaptive timeout state */
a->ato = PPTP_MAX_TIMEOUT;
a->rtt = priv->conf.peerPpd * PPTP_TIME_SCALE / 10; /* ppd in 10ths */
if (a->rtt < PPTP_MIN_RTT)
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 > 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;
/* Reset start time */
getmicrouptime(&priv->startTime);
/* Reset stats */
bzero(&priv->stats, sizeof(priv->stats));
/* Stop timers */
ng_pptpgre_stop_send_ack_timer(node);
ng_pptpgre_stop_recv_ack_timer(node);
}
/*
* Return the current time scaled & translated to our internally used format.
*/
static pptptime_t
ng_pptpgre_time(node_p node)
{
const priv_p priv = node->private;
struct timeval tv;
getmicrouptime(&tv);
if (tv.tv_sec < priv->startTime.tv_sec
|| (tv.tv_sec == priv->startTime.tv_sec
&& tv.tv_usec < priv->startTime.tv_usec))
return (0);
timevalsub(&tv, &priv->startTime);
tv.tv_sec *= PPTP_TIME_SCALE;
tv.tv_usec /= 1000000 / PPTP_TIME_SCALE;
return(tv.tv_sec + tv.tv_usec);
}
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