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Initial revision

/*
 * ccp.c
 *
 * Written by Archie Cobbs <archie@freebsd.org>
 * Copyright (c) 1995-1999 Whistle Communications, Inc. All rights reserved.
 * See ``COPYRIGHT.whistle''
 */

#include "defs.h"
#include "ppp.h"
#include "ccp.h"
#include "fsm.h"
#include "ngfunc.h"

#include <netgraph/ng_message.h>
#include <netgraph/ng_socket.h>
#include <netgraph.h>

/*
 * DEFINITIONS
 */

  #define CCP_MAXFAILURE	7

  #define CCP_KNOWN_CODES	(   (1 << CODE_CONFIGREQ)	\
				  | (1 << CODE_CONFIGACK)	\
				  | (1 << CODE_CONFIGNAK)	\
				  | (1 << CODE_CONFIGREJ)	\
				  | (1 << CODE_TERMREQ)		\
				  | (1 << CODE_TERMACK)		\
				  | (1 << CODE_CODEREJ)		\
				  | (1 << CODE_RESETREQ)	\
				  | (1 << CODE_RESETACK)	)

  /* Set menu options */
  enum {
    SET_ACCEPT,
    SET_DENY,
    SET_ENABLE,
    SET_DISABLE,
    SET_YES,
    SET_NO
  };

/*
 * INTERNAL FUNCTIONS
 */

  static void		CcpConfigure(Fsm fp);
  static void		CcpUnConfigure(Fsm fp);
  static u_char		*CcpBuildConfigReq(Fsm fp, u_char *cp);
  static void		CcpDecodeConfig(Fsm f, FsmOption a, int num, int mode);
  static void		CcpLayerUp(Fsm fp);
  static void		CcpLayerDown(Fsm fp);
  static void		CcpFailure(Fsm f, enum fsmfail reason);
  static void		CcpRecvResetReq(Fsm fp, int id, Mbuf bp);
  static void		CcpRecvResetAck(Fsm fp, int id, Mbuf bp);

  static int		CcpCheckEncryption(Bund b);
  static int		CcpSetCommand(Context ctx, int ac, char *av[], void *arg);
  static CompType	CcpFindComp(int type, int *indexp);
  static const char	*CcpTypeName(int type, char *buf, size_t len);

  static void		CcpNgCtrlEvent(int type, void *cookie);
  static void		CcpNgDataEvent(int type, void *cookie);

/*
 * GLOBAL VARIABLES
 */

  const struct cmdtab CcpSetCmds[] = {
    { "accept [opt ...]",		"Accept option",
	CcpSetCommand, NULL, 2, (void *) SET_ACCEPT },
    { "deny [opt ...]",			"Deny option",
	CcpSetCommand, NULL, 2, (void *) SET_DENY },
    { "enable [opt ...]",		"Enable option",
	CcpSetCommand, NULL, 2, (void *) SET_ENABLE },
    { "disable [opt ...]",		"Disable option",
	CcpSetCommand, NULL, 2, (void *) SET_DISABLE },
    { "yes [opt ...]",			"Enable and accept option",
	CcpSetCommand, NULL, 2, (void *) SET_YES },
    { "no [opt ...]",			"Disable and deny option",
	CcpSetCommand, NULL, 2, (void *) SET_NO },
    { NULL },
  };

/*
 * INTERNAL VARIABLES
 */

  /* These should be listed in order of preference */
  static const CompType		gCompTypes[] = {
#ifdef CCP_MPPC
    &gCompMppcInfo,
#endif
#ifdef CCP_DEFLATE
    &gCompDeflateInfo,
#endif
#ifdef CCP_PRED1
    &gCompPred1Info,
#endif
  };
  #define CCP_NUM_PROTOS	(sizeof(gCompTypes) / sizeof(*gCompTypes))

  /* Corresponding option list */
  static const struct confinfo	*gConfList;

  /* FSM Initializer */
  static const struct fsmtype gCcpFsmType = {
    "CCP",
    PROTO_CCP,
    CCP_KNOWN_CODES,
    FALSE,
    LG_CCP, LG_CCP2,
    NULL,
    CcpLayerUp,
    CcpLayerDown,
    NULL,
    NULL,
    CcpBuildConfigReq,
    CcpDecodeConfig,
    CcpConfigure,
    CcpUnConfigure,
    NULL,
    NULL,
    NULL,
    NULL,
    CcpFailure,
    CcpRecvResetReq,
    CcpRecvResetAck,
    NULL,
  };

  /* Names for different types of compression */
  static const struct ccpname {
    u_char	type;
    const char	*name;
  } gCcpTypeNames[] = {
    { CCP_TY_OUI,		"OUI" },
    { CCP_TY_PRED1,		"PRED1" },
    { CCP_TY_PRED2,		"PRED2" },
    { CCP_TY_PUDDLE,		"PUDDLE" },
    { CCP_TY_HWPPC,		"HWPPC" },
    { CCP_TY_STAC,		"STAC" },
    { CCP_TY_MPPC,		"MPPC" },
    { CCP_TY_GAND,		"GAND" },
    { CCP_TY_V42BIS,		"V42BIS" },
    { CCP_TY_BSD,		"BSD" },
    { CCP_TY_LZS_DCP,		"LZS-DCP" },
    { CCP_TY_DEFLATE24,		"DEFLATE24" },
    { CCP_TY_DCE,		"DCE" },
    { CCP_TY_DEFLATE,		"DEFLATE" },
    { CCP_TY_V44,		"V.44/LZJH" },
    { 0,			NULL },
  };

    int		gCcpCsock = -1;		/* Socket node control socket */
    int		gCcpDsock = -1;		/* Socket node data socket */
    EventRef	gCcpCtrlEvent;
    EventRef	gCcpDataEvent;

int
CcpsInit(void)
{
    char	name[NG_NODESIZ];

    /* Create a netgraph socket node */
    snprintf(name, sizeof(name), "mpd%d-cso", gPid);
    if (NgMkSockNode(name, &gCcpCsock, &gCcpDsock) < 0) {
	Perror("CcpsInit(): can't create %s node", NG_SOCKET_NODE_TYPE);
	return(-1);
    }
    (void) fcntl(gCcpCsock, F_SETFD, 1);
    (void) fcntl(gCcpDsock, F_SETFD, 1);

    /* Listen for happenings on our node */
    EventRegister(&gCcpCtrlEvent, EVENT_READ,
	gCcpCsock, EVENT_RECURRING, CcpNgCtrlEvent, NULL);
    EventRegister(&gCcpDataEvent, EVENT_READ,
	gCcpDsock, EVENT_RECURRING, CcpNgDataEvent, NULL);
	
    return (0);
}

void
CcpsShutdown(void)
{
    EventUnRegister(&gCcpCtrlEvent);
    close(gCcpCsock);
    gCcpCsock = -1;
    EventUnRegister(&gCcpDataEvent);
    close(gCcpDsock);
    gCcpDsock = -1;
}

/*
 * CcpInit()
 */

void
CcpInit(Bund b)
{
  CcpState	ccp = &b->ccp;

  /* Init CCP state for this bundle */
  memset(ccp, 0, sizeof(*ccp));
  FsmInit(&ccp->fsm, &gCcpFsmType, b);
  ccp->fsm.conf.maxfailure = CCP_MAXFAILURE;

  /* Construct options list if we haven't done so already */
  if (gConfList == NULL) {
    struct confinfo	*ci;
    int			k;

    ci = Malloc(MB_COMP, (CCP_NUM_PROTOS + 1) * sizeof(*ci));
    for (k = 0; k < CCP_NUM_PROTOS; k++) {
      ci[k].option = k;
      ci[k].peered = TRUE;
      ci[k].name = gCompTypes[k]->name;
    }

    /* Terminate list */
    ci[k].name = NULL;
    gConfList = (const struct confinfo *) ci;
  }
}

/*
 * CcpInst()
 */

void
CcpInst(Bund b, Bund bt)
{
  CcpState	ccp = &b->ccp;

  /* Init CCP state for this bundle */
  memcpy(ccp, &bt->ccp, sizeof(*ccp));
  FsmInst(&ccp->fsm, &bt->ccp.fsm, b);
}

/*
 * CcpConfigure()
 */

static void
CcpConfigure(Fsm fp)
{
    Bund 	b = (Bund)fp->arg;
    CcpState	const ccp = &b->ccp;
    int		k;

    /* Reset state */
    ccp->self_reject = 0;
    ccp->peer_reject = 0;
    ccp->crypt_check = 0;
    ccp->xmit = NULL;
    ccp->recv = NULL;
    for (k = 0; k < CCP_NUM_PROTOS; k++) {
	CompType	const ct = gCompTypes[k];

	if (ct->Configure) {
    	    if ((*ct->Configure)(b)) {
		if (Enabled(&ccp->options, k)) {
		    Log(LG_CCP, ("[%s] CCP: Protocol %s disabled "
			"as useless for this setup",
			b->name, ct->name));
		}
		CCP_SELF_REJ(ccp, k);
	    };
	}
    }
}

/*
 * CcpUnConfigure()
 */

static void
CcpUnConfigure(Fsm fp)
{
    Bund 	b = (Bund)fp->arg;
  CcpState	const ccp = &b->ccp;
  int		k;

  /* Reset state */
  ccp->self_reject = 0;
  ccp->peer_reject = 0;
  ccp->crypt_check = 0;
  ccp->xmit = NULL;
  ccp->recv = NULL;
  for (k = 0; k < CCP_NUM_PROTOS; k++) {
    CompType	const ct = gCompTypes[k];

    if (ct->UnConfigure)
      (*ct->UnConfigure)(b);
  }
}

/*
 * CcpNgCtrlEvent()
 *
 */

void
CcpNgCtrlEvent(int type, void *cookie)
{
    Bund		b = NULL;
    union {
        u_char		buf[2048];
        struct ng_mesg	msg;
    }			u;
    char		raddr[NG_PATHSIZ];
    int			i, len;
    ng_ID_t		id;

    /* Read message */
    if ((len = NgRecvMsg(gCcpCsock, &u.msg, sizeof(u), raddr)) < 0) {
	Perror("CcpNgCtrlEvent: can't read message");
	return;
    }
    
    if (sscanf(raddr, "[%x]:", &id) != 1) {
	Log(LG_ERR, ("CcpNgCtrlEvent: can't decode sender id: '%s'",
    	    raddr));
	return;
    }
    
    for (i = 0; i < gNumBundles; i++) {
	if (gBundles[i] && !gBundles[i]->dead &&
		gBundles[i]->ccp.decomp_node_id == id) {
	    b = gBundles[i];
	    break;
	}
    }
    if (!b)
	return;

    /* Examine message */
    switch (u.msg.header.typecookie) {

#ifdef USE_NG_MPPC
	case NGM_MPPC_COOKIE:
#endif
#ifdef USE_NG_DEFLATE
	case NGM_DEFLATE_COOKIE:
#endif
#ifdef USE_NG_PRED1
	case NGM_PRED1_COOKIE:
#endif
    	    CcpRecvMsg(b, &u.msg, len);
        return;

	default:
	    /* Unknown message */
	    Log(LG_ERR, ("CcpNgCtrlEvent: rec'd unknown ctrl message, cookie=%d cmd=%d",
		u.msg.header.typecookie, u.msg.header.cmd));
    	    break;
    }

}

/*
 * CcpNgDataEvent()
 */

static void
CcpNgDataEvent(int type, void *cookie)
{
    Bund		b;
    struct sockaddr_ng	naddr;
    socklen_t		nsize;
    Mbuf		bp;
    int			num = 0;
    char                *bundname, *rest;
    int                 id;
		
    while (1) {
	/* Protect from bundle shutdown and DoS */
	if (num > 100)
	    return;
    
	bp = mballoc(4096);

	/* Read data */
	nsize = sizeof(naddr);
	if ((bp->cnt = recvfrom(gCcpDsock, MBDATA(bp), MBSPACE(bp),
    		MSG_DONTWAIT, (struct sockaddr *)&naddr, &nsize)) < 0) {
	    mbfree(bp);
	    if (errno == EAGAIN)
    		return;
	    Log(LG_BUND|LG_ERR, ("CcpNgDataEvent: socket read: %s", strerror(errno)));
	    return;
	}
	num++;
    
	/* Debugging */
	LogDumpBp(LG_FRAME, bp,
	    "CcpNgDataEvent: rec'd %d bytes frame on %s hook", MBLEN(bp), naddr.sg_data);

	bundname = ((struct sockaddr_ng *)&naddr)->sg_data;
	if (bundname[0] != 'c' && bundname[0] != 'd') {
    	    Log(LG_ERR, ("CCP: Packet from unknown hook \"%s\"",
    	        bundname));
	    mbfree(bp);
    	    continue;
	}
	bundname++;
	id = strtol(bundname, &rest, 10);
	if (rest[0] != 0 || !gBundles[id] || gBundles[id]->dead) {
    	    Log(LG_ERR, ("CCP: Packet from unexisting bundle \"%s\"",
    		bundname));
	    mbfree(bp);
	    continue;
	}
		
	b = gBundles[id];

	/* Packet requiring compression */
	if (bundname[0] == 'c') {
	    bp = CcpDataOutput(b, bp);
	} else {
	    /* Packet requiring decompression */
	    bp = CcpDataInput(b, bp);
	}
	if (bp)
	    NgFuncWriteFrame(gCcpDsock, naddr.sg_data, b->name, bp);
    }
}

/*
 * CcpRecvMsg()
 */

void
CcpRecvMsg(Bund b, struct ng_mesg *msg, int len)
{
  CcpState	const ccp = &b->ccp;
  Fsm		const fp = &ccp->fsm;

  switch (msg->header.typecookie) {
#ifdef USE_NG_MPPC
    case NGM_MPPC_COOKIE:
      switch (msg->header.cmd) {
	case NGM_MPPC_RESETREQ: {
	    CcpSendResetReq(b);
	    return;
	  }
	default:
	  break;
      }
      break;
#endif
#ifdef USE_NG_DEFLATE
    case NGM_DEFLATE_COOKIE:
      switch (msg->header.cmd) {
	case NGM_DEFLATE_RESETREQ: {
	    CcpSendResetReq(b);
	    return;
	  }
	default:
	  break;
      }
      break;
#endif
#ifdef USE_NG_PRED1
    case NGM_PRED1_COOKIE:
      switch (msg->header.cmd) {
	case NGM_PRED1_RESETREQ: {
	    CcpSendResetReq(b);
	    return;
	  }
	default:
	  break;
      }
      break;
#endif
    default:
      break;
  }

  /* Unknown! */
  Log(LG_ERR, ("[%s] %s: rec'd unknown netgraph message: cookie=%d, cmd=%d",
    Pref(fp), Fsm(fp), msg->header.typecookie, msg->header.cmd));
}

/*
 * CcpUp()
 */

void
CcpUp(Bund b)
{
  FsmUp(&b->ccp.fsm);
}

/*
 * CcpDown()
 */

void
CcpDown(Bund b)
{
  FsmDown(&b->ccp.fsm);
}

/*
 * CcpOpen()
 */

void
CcpOpen(Bund b)
{
  FsmOpen(&b->ccp.fsm);
}

/*
 * CcpClose()
 */

void
CcpClose(Bund b)
{
  FsmClose(&b->ccp.fsm);
}

/*
 * CcpOpenCmd()
 */

int
CcpOpenCmd(Context ctx)
{
    if (ctx->bund->tmpl)
	Error("impossible to open template");
    FsmOpen(&ctx->bund->ccp.fsm);
    return (0);
}

/*
 * CcpCloseCmd()
 */

int
CcpCloseCmd(Context ctx)
{
    if (ctx->bund->tmpl)
	Error("impossible to close template");
    FsmClose(&ctx->bund->ccp.fsm);
    return (0);
}

/*
 * CcpFailure()
 *
 * If we fail, just shut down and stop trying. However, if encryption
 * was required and MPPE encryption was enabled, then die here as well.
 */

static void
CcpFailure(Fsm fp, enum fsmfail reason)
{
    Bund 	b = (Bund)fp->arg;
    CcpCheckEncryption(b);
}

/*
 * CcpStat()
 */

int
CcpStat(Context ctx, int ac, char *av[], void *arg)
{
  CcpState	const ccp = &ctx->bund->ccp;
  char		buf[64];

  Printf("[%s] %s [%s]\r\n", Pref(&ccp->fsm), Fsm(&ccp->fsm), FsmStateName(ccp->fsm.state));
  Printf("Enabled protocols:\r\n");
  OptStat(ctx, &ccp->options, gConfList);

#ifdef CCP_MPPC
  MppcStat(ctx, ac, av, arg);
#endif
  Printf("Outgoing compression:\r\n");
  Printf("\tProto\t: %s (%s)\r\n", !ccp->xmit ? "none" : ccp->xmit->name,
    (ccp->xmit && ccp->xmit->Describe) ? (*ccp->xmit->Describe)(ctx->bund, COMP_DIR_XMIT, buf, sizeof(buf)) : "");
  if (ccp->xmit && ccp->xmit->Stat)
    ccp->xmit->Stat(ctx, COMP_DIR_XMIT);
  Printf("\tResets\t: %d\r\n", ccp->xmit_resets);

  Printf("Incoming decompression:\r\n");
  Printf("\tProto\t: %s (%s)\r\n", !ccp->recv ? "none" : ccp->recv->name,
    (ccp->recv && ccp->recv->Describe) ? (*ccp->recv->Describe)(ctx->bund, COMP_DIR_RECV, buf, sizeof(buf)) : "");
  if (ccp->recv && ccp->recv->Stat)
    ccp->recv->Stat(ctx, COMP_DIR_RECV);
  Printf("\tResets\t: %d\r\n", ccp->recv_resets);

  return(0);
}

/*
 * CcpSendResetReq()
 */

void
CcpSendResetReq(Bund b)
{
  CcpState	const ccp = &b->ccp;
  CompType	const ct = ccp->recv;
  Fsm		const fp = &ccp->fsm;
  Mbuf		bp = NULL;

  if (ct == NULL) {
    Log(LG_ERR, ("[%s] %s: CcpSendResetReq() call from undefined decompressor!", 
	Pref(fp), Fsm(fp)));
    return;
  }
  
  ccp->recv_resets++;
  if (ct->SendResetReq)
    bp = (*ct->SendResetReq)(b);
  Log(LG_CCP, ("[%s] %s: SendResetReq #%d link %d (%s)", 
    Pref(fp), Fsm(fp), fp->reqid, 0, FsmStateName(fp->state)));
  FsmOutputMbuf(fp, CODE_RESETREQ, fp->reqid++, bp);
}

/*
 * CcpRecvResetReq()
 */

static void
CcpRecvResetReq(Fsm fp, int id, Mbuf bp)
{
    Bund 	b = (Bund)fp->arg;
  CcpState	const ccp = &b->ccp;
  CompType	const ct = ccp->xmit;
  int		noAck = 0;

  ccp->xmit_resets++;
  bp = (ct && ct->RecvResetReq) ? (*ct->RecvResetReq)(b, id, bp, &noAck) : NULL;
  if (!noAck) {
    Log(LG_CCP, ("[%s] %s: SendResetAck #%d link %d (%s)",
	Pref(fp), Fsm(fp), id, 0, FsmStateName(fp->state)));
    FsmOutputMbuf(fp, CODE_RESETACK, id, bp);
  }
}

/*
 * CcpRecvResetAck()
 */

static void
CcpRecvResetAck(Fsm fp, int id, Mbuf bp)
{
    Bund 	b = (Bund)fp->arg;
  CcpState	const ccp = &b->ccp;
  CompType	const ct = ccp->recv;

  if (ct && ct->RecvResetAck)
    (*ct->RecvResetAck)(b, id, bp);
}

/*
 * CcpInput()
 */

void
CcpInput(Bund b, Mbuf bp)
{
  FsmInput(&b->ccp.fsm, bp);
}

/*
 * CcpDataOutput()
 *
 * Compress a frame. Consumes the original packet.
 */

Mbuf
CcpDataOutput(Bund b, Mbuf plain)
{
  CcpState	const ccp = &b->ccp;
  Mbuf		comp;

  LogDumpBp(LG_FRAME, plain, "[%s] %s: xmit plain", Pref(&ccp->fsm), Fsm(&ccp->fsm));

/* Compress packet */

  if ((!ccp->xmit) || (!ccp->xmit->Compress))
  {
    Log(LG_ERR, ("[%s] %s: no encryption for xmit", Pref(&ccp->fsm), Fsm(&ccp->fsm)));
    mbfree(plain);
    return(NULL);
  }
  comp = (*ccp->xmit->Compress)(b, plain);
  LogDumpBp(LG_FRAME, comp, "[%s] %s: xmit comp", Pref(&ccp->fsm), Fsm(&ccp->fsm));

  return(comp);
}

/*
 * CcpDataInput()
 *
 * Decompress incoming packet. If packet got garbled, return NULL.
 * In any case, we consume the packet passed to us.
 */

Mbuf
CcpDataInput(Bund b, Mbuf comp)
{
  CcpState	const ccp = &b->ccp;
  Mbuf		plain;

  LogDumpBp(LG_FRAME, comp, "[%s] %s: recv comp", Pref(&ccp->fsm), Fsm(&ccp->fsm));

/* Decompress packet */

  if ((!ccp->recv) || (!ccp->recv->Decompress))
  {
    Log(LG_ERR, ("[%s] %s: no compression for recv", Pref(&ccp->fsm), Fsm(&ccp->fsm)));
    mbfree(comp);
    return(NULL);
  }

  plain = (*ccp->recv->Decompress)(b, comp);

/* Encrypted ok? */

  if (plain == NULL)
  {
    Log(LG_CCP, ("[%s] %s: decompression failed", Pref(&ccp->fsm), Fsm(&ccp->fsm)));
    return(NULL);
  }
  LogDumpBp(LG_FRAME, plain, "[%s] %s: recv plain", Pref(&ccp->fsm), Fsm(&ccp->fsm));

  return(plain);
}

/*
 * CcpBuildConfigReq()
 */

static u_char *
CcpBuildConfigReq(Fsm fp, u_char *cp)
{
    Bund 	b = (Bund)fp->arg;
    CcpState	const ccp = &b->ccp;
    int		type;
    int		ok;

    /* Put in all options that peer hasn't rejected in preferred order */
    ccp->xmit = NULL;
    for (type = 0; type < CCP_NUM_PROTOS; type++) {
	CompType	const ct = gCompTypes[type];

	if (Enabled(&ccp->options, type) && !CCP_PEER_REJECTED(ccp, type)) {
    	    cp = (*ct->BuildConfigReq)(b, cp, &ok);
    	    if (ok && (!ccp->xmit))
		ccp->xmit = ct;
	}
    }
    return(cp);
}

/*
 * CcpLayerUp()
 */

static void
CcpLayerUp(Fsm fp)
{
    Bund 	b = (Bund)fp->arg;
  CcpState	const ccp = &b->ccp;
  struct ngm_connect    cn;
  char		buf[64];

  /* If nothing was negotiated in either direction, close CCP */
  if ((!ccp->recv || !(*ccp->recv->Negotiated)(b, COMP_DIR_RECV))
      && (!ccp->xmit || !(*ccp->xmit->Negotiated)(b, COMP_DIR_XMIT))) {
    Log(LG_CCP, ("[%s] %s: No compression negotiated", Pref(fp), Fsm(fp)));
    FsmFailure(fp, FAIL_NEGOT_FAILURE);
    return;
  }

  /* Check for required encryption */
  if (CcpCheckEncryption(b) < 0) {
    return;
  }

  /* Initialize each direction */
  if (ccp->xmit != NULL && ccp->xmit->Init != NULL
      && (*ccp->xmit->Init)(b, COMP_DIR_XMIT) < 0) {
    Log(LG_CCP, ("[%s] %s: compression init failed", Pref(fp), Fsm(fp)));
    FsmFailure(fp, FAIL_NEGOT_FAILURE);		/* XXX */
    return;
  }
  if (ccp->recv != NULL && ccp->recv->Init != NULL
      && (*ccp->recv->Init)(b, COMP_DIR_RECV) < 0) {
    Log(LG_CCP, ("[%s] %s: decompression init failed", Pref(fp), Fsm(fp)));
    FsmFailure(fp, FAIL_NEGOT_FAILURE);		/* XXX */
    return;
  }

  if (ccp->xmit != NULL && ccp->xmit->Compress != NULL) {
    /* Connect a hook from the ppp node to our socket node */
    snprintf(cn.path, sizeof(cn.path), "[%x]:", b->nodeID);
    snprintf(cn.ourhook, sizeof(cn.ourhook), "c%d", b->id);
    strcpy(cn.peerhook, NG_PPP_HOOK_COMPRESS);
    if (NgSendMsg(gCcpCsock, ".:",
	    NGM_GENERIC_COOKIE, NGM_CONNECT, &cn, sizeof(cn)) < 0) {
	Perror("[%s] can't connect \"%s\"->\"%s\" and \"%s\"->\"%s\"",
    	    b->name, ".:", cn.ourhook, cn.path, cn.peerhook);
    }
  }

  if (ccp->recv != NULL && ccp->recv->Decompress != NULL) {
    /* Connect a hook from the ppp node to our socket node */
    snprintf(cn.path, sizeof(cn.path), "[%x]:", b->nodeID);
    snprintf(cn.ourhook, sizeof(cn.ourhook), "d%d", b->id);
    strcpy(cn.peerhook, NG_PPP_HOOK_DECOMPRESS);
    if (NgSendMsg(gCcpCsock, ".:",
	    NGM_GENERIC_COOKIE, NGM_CONNECT, &cn, sizeof(cn)) < 0) {
	Perror("[%s] can't connect \"%s\"->\"%s\" and \"%s\"->\"%s\"",
    	    b->name, ".:", cn.ourhook, cn.path, cn.peerhook);
    }
  }

  /* Report what we're doing */
  Log(LG_CCP, ("[%s] CCP: Compress using: %s (%s)", b->name, !ccp->xmit ? "none" : ccp->xmit->name,
    (ccp->xmit && ccp->xmit->Describe) ? (*ccp->xmit->Describe)(b, COMP_DIR_XMIT, buf, sizeof(buf)) : ""));
  Log(LG_CCP, ("[%s] CCP: Decompress using: %s (%s)", b->name, !ccp->recv ? "none" : ccp->recv->name,
    (ccp->recv && ccp->recv->Describe) ? (*ccp->recv->Describe)(b, COMP_DIR_RECV, buf, sizeof(buf)) : ""));

  /* Update PPP node config */
  b->pppConfig.bund.enableCompression = (ccp->xmit != NULL)?ccp->xmit->mode:0;
  b->pppConfig.bund.enableDecompression = (ccp->recv != NULL)?ccp->recv->mode:0;
  NgFuncSetConfig(b);

  /* Update interface MTU */
  BundUpdateParams(b);
}

/*
 * CcpLayerDown()
 */

static void
CcpLayerDown(Fsm fp)
{
    Bund 	b = (Bund)fp->arg;
  CcpState	const ccp = &b->ccp;

  /* Update PPP node config */
  b->pppConfig.bund.enableCompression = 0;
  b->pppConfig.bund.enableDecompression = 0;
  NgFuncSetConfig(b);

  /* Update interface MTU */
  BundUpdateParams(b);
  
  if (ccp->xmit != NULL && ccp->xmit->Compress != NULL) {
    char	hook[NG_HOOKSIZ];
    /* Disconnect hook. */
    snprintf(hook, sizeof(hook), "c%d", b->id);
    NgFuncDisconnect(gCcpCsock, b->name, ".:", hook);
  }
  
  if (ccp->recv != NULL && ccp->recv->Decompress != NULL) {
    char	hook[NG_HOOKSIZ];
    /* Disconnect hook. */
    snprintf(hook, sizeof(hook), "d%d", b->id);
    NgFuncDisconnect(gCcpCsock, b->name, ".:", hook);
  }
  if (ccp->recv && ccp->recv->Cleanup)
    (*ccp->recv->Cleanup)(b, COMP_DIR_RECV);
  if (ccp->xmit && ccp->xmit->Cleanup)
    (*ccp->xmit->Cleanup)(b, COMP_DIR_XMIT);

  ccp->xmit_resets = 0;
  ccp->recv_resets = 0;
}

/*
 * CcpDecodeConfig()
 */

static void
CcpDecodeConfig(Fsm fp, FsmOption list, int num, int mode)
{
    Bund 	b = (Bund)fp->arg;
  CcpState	const ccp = &b->ccp;
  u_int		ackSizeSave, rejSizeSave;
  int		k, rej;

  /* Forget our previous choice on new request */
  if (mode == MODE_REQ)
    ccp->recv = NULL;

  /* Decode each config option */
  for (k = 0; k < num; k++) {
    FsmOption	const opt = &list[k];
    int		index;
    CompType	ct;
    char	buf[32];

    Log(LG_CCP, ("[%s]   %s", b->name, CcpTypeName(opt->type, buf, sizeof(buf))));
    if ((ct = CcpFindComp(opt->type, &index)) == NULL) {
      if (mode == MODE_REQ) {
	Log(LG_CCP, ("[%s]     Not supported", b->name));
	FsmRej(fp, opt);
      }
      continue;
    }
    switch (mode) {
      case MODE_REQ:
	ackSizeSave = gAckSize;
	rejSizeSave = gRejSize;
	rej = (!Acceptable(&ccp->options, index)
	  || CCP_SELF_REJECTED(ccp, index)
	  || (ccp->recv && ccp->recv != ct));
	if (rej) {
	  (*ct->DecodeConfig)(fp, opt, MODE_NOP);
	  FsmRej(fp, opt);
	  break;
	}
	(*ct->DecodeConfig)(fp, opt, mode);
	if (gRejSize != rejSizeSave) {		/* we rejected it */
	  CCP_SELF_REJ(ccp, index);
	  break;
	}
	if (gAckSize != ackSizeSave)		/* we accepted it */
	  ccp->recv = ct;
	break;

      case MODE_REJ:
	(*ct->DecodeConfig)(fp, opt, mode);
	CCP_PEER_REJ(ccp, index);
	break;

      case MODE_NAK:
      case MODE_NOP:
	(*ct->DecodeConfig)(fp, opt, mode);
	break;
    }
  }
}

/*
 * CcpSubtractBloat()
 *
 * Given that "size" is our MTU, return the maximum length frame
 * we can compress without the result being longer than "size".
 */

int
CcpSubtractBloat(Bund b, int size)
{
  CcpState	const ccp = &b->ccp;

  /* Account for transmit compression overhead */
  if (OPEN_STATE(ccp->fsm.state) && ccp->xmit && ccp->xmit->SubtractBloat)
    size = (*ccp->xmit->SubtractBloat)(b, size);

  /* Account for CCP's protocol number overhead */
  if (OPEN_STATE(ccp->fsm.state))
    size -= CCP_OVERHEAD;

  /* Done */
  return(size);
}

/*
 * CcpCheckEncryption()
 *
 * Because MPPE is negotiated as an option to MPPC compression,
 * we have to check for encryption required when CCP comes up.
 */

static int
CcpCheckEncryption(Bund b)
{
#if 0
  CcpState	const ccp = &b->ccp;

  /* Already checked? */
  if (ccp->crypt_check)
    return(0);
  ccp->crypt_check = 1;

  /* Is encryption required? */
  if (Enabled(&ccp->options, gMppePolicy)) {
    if (b->params.msoft.policy != MPPE_POLICY_REQUIRED) 
      return(0);
  } else {
    if (!Enabled(&b->conf.options, BUND_CONF_CRYPT_REQD))
      return(0);
  }

  /* Was MPPE encryption enabled? If not, ignore requirement */
  if (!Enabled(&ccp->options, gMppe40)
      && !Enabled(&ccp->options, gMppe56)
      && !Enabled(&ccp->options, gMppe128)
      && !Enabled(&ccp->options, gMppePolicy))
    return(0);

  /* Make sure MPPE was negotiated in both directions */
  if (!OPEN_STATE(ccp->fsm.state)
      || !ccp->xmit || ccp->xmit->type != CCP_TY_MPPC
      || !ccp->recv || ccp->recv->type != CCP_TY_MPPC
#ifdef CCP_MPPC
      || !(ccp->mppc.recv_bits & MPPE_BITS)
      || !(ccp->mppc.xmit_bits & MPPE_BITS)
#endif
      )
    goto fail;

  /* Looks OK */
  return(0);

fail:
  Log(LG_ERR, ("[%s] %s: encryption required, but MPPE was not"
    " negotiated in both directions", Pref(&ccp->fsm), Fsm(&ccp->fsm)));
  FsmFailure(&ccp->fsm, FAIL_CANT_ENCRYPT);
  FsmFailure(&b->ipcp.fsm, FAIL_CANT_ENCRYPT);
  FsmFailure(&b->ipv6cp.fsm, FAIL_CANT_ENCRYPT);
  return(-1);
#endif
    return (0);
}

/*
 * CcpSetCommand()
 */

static int
CcpSetCommand(Context ctx, int ac, char *av[], void *arg)
{
  CcpState	const ccp = &ctx->bund->ccp;

  if (ac == 0)
    return(-1);
  switch ((intptr_t)arg) {
    case SET_ACCEPT:
      AcceptCommand(ac, av, &ccp->options, gConfList);
      break;

    case SET_DENY:
      DenyCommand(ac, av, &ccp->options, gConfList);
      break;

    case SET_ENABLE:
      EnableCommand(ac, av, &ccp->options, gConfList);
      break;

    case SET_DISABLE:
      DisableCommand(ac, av, &ccp->options, gConfList);
      break;

    case SET_YES:
      YesCommand(ac, av, &ccp->options, gConfList);
      break;

    case SET_NO:
      NoCommand(ac, av, &ccp->options, gConfList);
      break;

    default:
      assert(0);
  }
  return(0);
}

/*
 * CcpFindComp()
 */

static CompType
CcpFindComp(int type, int *indexp)
{
  int	k;

  for (k = 0; k < CCP_NUM_PROTOS; k++) {
    if (gCompTypes[k]->type == type) {
      if (indexp)
	*indexp = k;
      return(gCompTypes[k]);
    }
  }
  return(NULL);
}

/*
 * CcpTypeName()
 */

static const char *
CcpTypeName(int type, char *buf, size_t len)
{
  const struct ccpname	*p;

  for (p = gCcpTypeNames; p->name; p++) {
    if (p->type == type) {
	strlcpy(buf, p->name, len);
        return (buf);
    }
  }
  snprintf(buf, sizeof(buf), "UNKNOWN[%d]", type);
  return(buf);
}