ppp_comp.c

经典的ppp程序

/*
 * ppp_comp.c - STREAMS module for kernel-level compression and CCP support.
 *
 * Copyright (c) 1994 The Australian National University.
 * All rights reserved.
 *
 * Permission to use, copy, modify, and distribute this software and its
 * documentation is hereby granted, provided that the above copyright
 * notice appears in all copies.  This software is provided without any
 * warranty, express or implied. The Australian National University
 * makes no representations about the suitability of this software for
 * any purpose.
 *
 * IN NO EVENT SHALL THE AUSTRALIAN NATIONAL UNIVERSITY BE LIABLE TO ANY
 * PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
 * THE AUSTRALIAN NATIONAL UNIVERSITY HAS BEEN ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 *
 * THE AUSTRALIAN NATIONAL UNIVERSITY SPECIFICALLY DISCLAIMS ANY WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
 * ON AN "AS IS" BASIS, AND THE AUSTRALIAN NATIONAL UNIVERSITY HAS NO
 * OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS,
 * OR MODIFICATIONS.
 *
 * $Id: ppp_comp.c,v 1.12 1999/09/15 23:49:06 masputra Exp $
 */

/*
 * This file is used under SVR4, Solaris 2, SunOS 4, and Digital UNIX.
 */

#include <sys/types.h>
#include <sys/param.h>
#include <sys/errno.h>
#include <sys/stream.h>

#ifdef SVR4
#include <sys/conf.h>
#include <sys/cmn_err.h>
#include <sys/ddi.h>
#else
#include <sys/user.h>
#ifdef __osf__
#include <sys/cmn_err.h>
#endif
#endif /* SVR4 */

#include <net/ppp_defs.h>
#include <net/pppio.h>
#include "ppp_mod.h"

#ifdef __osf__
#include <sys/mbuf.h>
#include <sys/protosw.h>
#endif

#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <net/vjcompress.h>

#define PACKETPTR	mblk_t *
#include <net/ppp-comp.h>

MOD_OPEN_DECL(ppp_comp_open);
MOD_CLOSE_DECL(ppp_comp_close);
static int ppp_comp_rput __P((queue_t *, mblk_t *));
static int ppp_comp_rsrv __P((queue_t *));
static int ppp_comp_wput __P((queue_t *, mblk_t *));
static int ppp_comp_wsrv __P((queue_t *));
static void ppp_comp_ccp __P((queue_t *, mblk_t *, int));
static int msg_byte __P((mblk_t *, unsigned int));

/* Extract byte i of message mp. */
#define MSG_BYTE(mp, i)	((i) < (mp)->b_wptr - (mp)->b_rptr? (mp)->b_rptr[i]: \
			 msg_byte((mp), (i)))

/* Is this LCP packet one we have to transmit using LCP defaults? */
#define LCP_USE_DFLT(mp)	(1 <= (code = MSG_BYTE((mp), 4)) && code <= 7)

#define PPP_COMP_ID 0xbadf
static struct module_info minfo = {
#ifdef PRIOQ
    PPP_COMP_ID, "ppp_comp", 0, INFPSZ, 16512, 16384,
#else
    PPP_COMP_ID, "ppp_comp", 0, INFPSZ, 16384, 4096,
#endif
};

static struct qinit r_init = {
    ppp_comp_rput, ppp_comp_rsrv, ppp_comp_open, ppp_comp_close,
    NULL, &minfo, NULL
};

static struct qinit w_init = {
    ppp_comp_wput, ppp_comp_wsrv, NULL, NULL, NULL, &minfo, NULL
};

#if defined(SVR4) && !defined(SOL2)
int pcmpdevflag = 0;
#define ppp_compinfo pcmpinfo
#endif
struct streamtab ppp_compinfo = {
    &r_init, &w_init, NULL, NULL
};

int ppp_comp_count;		/* number of module instances in use */

#ifdef __osf__

static void ppp_comp_alloc __P((comp_state_t *));
typedef struct memreq {
    unsigned char comp_opts[20];
    int cmd;
    int thread_status;
    char *returned_mem;
} memreq_t;

#endif

typedef struct comp_state {
    int		flags;
    int		mru;
    int		mtu;
    int		unit;
    struct compressor *xcomp;
    void	*xstate;
    struct compressor *rcomp;
    void	*rstate;
    struct vjcompress vj_comp;
    int		vj_last_ierrors;
    struct pppstat stats;
#ifdef __osf__
    memreq_t	memreq;
    thread_t	thread;
#endif
} comp_state_t;


#ifdef __osf__
extern task_t first_task;
#endif

/* Bits in flags are as defined in pppio.h. */
#define CCP_ERR		(CCP_ERROR | CCP_FATALERROR)
#define LAST_MOD	0x1000000	/* no ppp modules below us */
#define DBGLOG		0x2000000	/* log debugging stuff */

#define MAX_IPHDR	128	/* max TCP/IP header size */
#define MAX_VJHDR	20	/* max VJ compressed header size (?) */

#undef MIN		/* just in case */
#define MIN(a, b)	((a) < (b)? (a): (b))

/*
 * List of compressors we know about.
 */

#if DO_BSD_COMPRESS
extern struct compressor ppp_bsd_compress;
#endif
#if DO_DEFLATE
extern struct compressor ppp_deflate, ppp_deflate_draft;
#endif

struct compressor *ppp_compressors[] = {
#if DO_BSD_COMPRESS
    &ppp_bsd_compress,
#endif
#if DO_DEFLATE
    &ppp_deflate,
    &ppp_deflate_draft,
#endif
    NULL
};

/*
 * STREAMS module entry points.
 */
MOD_OPEN(ppp_comp_open)
{
    comp_state_t *cp;
#ifdef __osf__
    thread_t thread;
#endif

    if (q->q_ptr == NULL) {
	cp = (comp_state_t *) ALLOC_SLEEP(sizeof(comp_state_t));
	if (cp == NULL)
	    OPEN_ERROR(ENOSR);
	bzero((caddr_t)cp, sizeof(comp_state_t));
	WR(q)->q_ptr = q->q_ptr = (caddr_t) cp;
	cp->mru = PPP_MRU;
	cp->mtu = PPP_MTU;
	cp->xstate = NULL;
	cp->rstate = NULL;
	vj_compress_init(&cp->vj_comp, -1);
#ifdef __osf__
	if (!(thread = kernel_thread_w_arg(first_task, ppp_comp_alloc, (void *)cp)))
		OPEN_ERROR(ENOSR);
	cp->thread = thread;
#endif
	++ppp_comp_count;
	qprocson(q);
    }
    return 0;
}

MOD_CLOSE(ppp_comp_close)
{
    comp_state_t *cp;

    qprocsoff(q);
    cp = (comp_state_t *) q->q_ptr;
    if (cp != NULL) {
	if (cp->xstate != NULL)
	    (*cp->xcomp->comp_free)(cp->xstate);
	if (cp->rstate != NULL)
	    (*cp->rcomp->decomp_free)(cp->rstate);
#ifdef __osf__
	if (!cp->thread)
	    printf("ppp_comp_close: NULL thread!\n");
	else
	    thread_terminate(cp->thread);
#endif
	FREE(cp, sizeof(comp_state_t));
	q->q_ptr = NULL;
	OTHERQ(q)->q_ptr = NULL;
	--ppp_comp_count;
    }
    return 0;
}

#ifdef __osf__

/* thread for calling back to a compressor's memory allocator
 * Needed for Digital UNIX since it's VM can't handle requests
 * for large amounts of memory without blocking.  The thread
 * provides a context in which we can call a memory allocator
 * that may block.
 */
static void
ppp_comp_alloc(comp_state_t *cp)
{
    int len, cmd;
    unsigned char *compressor_options;
    thread_t thread;
    void *(*comp_allocator)();


#if defined(MAJOR_VERSION) && (MAJOR_VERSION <= 2)

    /* In 2.x and earlier the argument gets passed
     * in the thread structure itself.  Yuck.
     */
    thread = current_thread();
    cp = thread->reply_port;
    thread->reply_port = PORT_NULL;

#endif

    for (;;) {
	assert_wait((vm_offset_t)&cp->memreq.thread_status, TRUE);
	thread_block();

	if (thread_should_halt(current_thread()))
	    thread_halt_self();
	cmd = cp->memreq.cmd;
	compressor_options = &cp->memreq.comp_opts[0];
	len = compressor_options[1];
	if (cmd == PPPIO_XCOMP) {
	    cp->memreq.returned_mem = cp->xcomp->comp_alloc(compressor_options, len);
	    if (!cp->memreq.returned_mem) {
		cp->memreq.thread_status = ENOSR;
	    } else {
		cp->memreq.thread_status = 0;
	    }
	} else {
	    cp->memreq.returned_mem = cp->rcomp->decomp_alloc(compressor_options, len);
	    if (!cp->memreq.returned_mem) {
	        cp->memreq.thread_status = ENOSR;
	    } else {
		cp->memreq.thread_status = 0;
	    }
	}
    }
}

#endif /* __osf__ */

/* here's the deal with memory allocation under Digital UNIX.
 * Some other may also benefit from this...
 * We can't ask for huge chunks of memory in a context where
 * the caller can't be put to sleep (like, here.)  The alloc
 * is likely to fail.  Instead we do this: the first time we
 * get called, kick off a thread to do the allocation.  Return
 * immediately to the caller with EAGAIN, as an indication that
 * they should send down the ioctl again.  By the time the
 * second call comes in it's likely that the memory allocation
 * thread will have returned with the requested memory.  We will
 * continue to return EAGAIN however until the thread has completed.
 * When it has, we return zero (and the memory) if the allocator
 * was successful and ENOSR otherwise.
 *
 * Callers of the RCOMP and XCOMP ioctls are encouraged (but not
 * required) to loop for some number of iterations with a small
 * delay in the loop body (for instance a 1/10-th second "sleep"
 * via select.)
 */
static int
ppp_comp_wput(q, mp)
    queue_t *q;
    mblk_t *mp;
{
    struct iocblk *iop;
    comp_state_t *cp;
    int error, len, n;
    int flags, mask;
    mblk_t *np;
    struct compressor **comp;
    struct ppp_stats *psp;
    struct ppp_comp_stats *csp;
    unsigned char *opt_data;
    int nxslots, nrslots;

    cp = (comp_state_t *) q->q_ptr;
    if (cp == 0) {
	DPRINT("cp == 0 in ppp_comp_wput\n");
	freemsg(mp);
	return 0;
    }

    switch (mp->b_datap->db_type) {

    case M_DATA:
	putq(q, mp);
	break;

    case M_IOCTL:
	iop = (struct iocblk *) mp->b_rptr;
	error = EINVAL;
	switch (iop->ioc_cmd) {

	case PPPIO_CFLAGS:
	    /* set/get CCP state */
	    if (iop->ioc_count != 2 * sizeof(int))
		break;
	    if (mp->b_cont == 0) {
		DPRINT1("ppp_comp_wput/%d: PPPIO_CFLAGS b_cont = 0!\n", cp->unit);
		break;
	    }
	    flags = ((int *) mp->b_cont->b_rptr)[0];
	    mask = ((int *) mp->b_cont->b_rptr)[1];
	    cp->flags = (cp->flags & ~mask) | (flags & mask);
	    if ((mask & CCP_ISOPEN) && (flags & CCP_ISOPEN) == 0) {
		if (cp->xstate != NULL) {
		    (*cp->xcomp->comp_free)(cp->xstate);
		    cp->xstate = NULL;
		}
		if (cp->rstate != NULL) {
		    (*cp->rcomp->decomp_free)(cp->rstate);
		    cp->rstate = NULL;
		}
		cp->flags &= ~CCP_ISUP;
	    }
	    error = 0;
	    iop->ioc_count = sizeof(int);
	    ((int *) mp->b_cont->b_rptr)[0] = cp->flags;
	    mp->b_cont->b_wptr = mp->b_cont->b_rptr + sizeof(int);
	    break;

	case PPPIO_VJINIT:
	    /*
	     * Initialize VJ compressor/decompressor
	     */
	    if (iop->ioc_count != 2)
		break;
	    if (mp->b_cont == 0) {
		DPRINT1("ppp_comp_wput/%d: PPPIO_VJINIT b_cont = 0!\n", cp->unit);
		break;
	    }
	    nxslots = mp->b_cont->b_rptr[0] + 1;
	    nrslots = mp->b_cont->b_rptr[1] + 1;
	    if (nxslots > MAX_STATES || nrslots > MAX_STATES)
		break;
	    vj_compress_init(&cp->vj_comp, nxslots);
	    cp->vj_last_ierrors = cp->stats.ppp_ierrors;
	    error = 0;
	    iop->ioc_count = 0;
	    break;

	case PPPIO_XCOMP:
	case PPPIO_RCOMP:
	    if (iop->ioc_count <= 0)
		break;
	    if (mp->b_cont == 0) {
		DPRINT1("ppp_comp_wput/%d: PPPIO_[XR]COMP b_cont = 0!\n", cp->unit);
		break;
	    }
	    opt_data = mp->b_cont->b_rptr;
	    len = mp->b_cont->b_wptr - opt_data;
	    if (len > iop->ioc_count)
		len = iop->ioc_count;
	    if (opt_data[1] < 2 || opt_data[1] > len)
		break;
	    for (comp = ppp_compressors; *comp != NULL; ++comp)
		if ((*comp)->compress_proto == opt_data[0]) {
		    /* here's the handler! */
		    error = 0;
#ifndef __osf__
		    if (iop->ioc_cmd == PPPIO_XCOMP) {
			/* A previous call may have fetched memory for a compressor
			 * that's now being retired or reset.  Free it using it's
			 * mechanism for freeing stuff.
			 */
			if (cp->xstate != NULL) {
			    (*cp->xcomp->comp_free)(cp->xstate);
			    cp->xstate = NULL;
			}
			cp->xcomp = *comp;
			cp->xstate = (*comp)->comp_alloc(opt_data, len);
			if (cp->xstate == NULL)
			    error = ENOSR;
		    } else {
			if (cp->rstate != NULL) {
			    (*cp->rcomp->decomp_free)(cp->rstate);
			    cp->rstate = NULL;
			}
			cp->rcomp = *comp;
			cp->rstate = (*comp)->decomp_alloc(opt_data, len);
			if (cp->rstate == NULL)
			    error = ENOSR;
		    }
#else
		    if ((error = cp->memreq.thread_status) != EAGAIN)
		    if (iop->ioc_cmd == PPPIO_XCOMP) {
			if (cp->xstate) {
			    (*cp->xcomp->comp_free)(cp->xstate);
			    cp->xstate = 0;
			}
			/* sanity check for compressor options
			 */
			if (sizeof (cp->memreq.comp_opts) < len) {
			    printf("can't handle options for compressor %d (%d)\n", opt_data[0],
				opt_data[1]);
			    cp->memreq.thread_status = ENOSR;
			    cp->memreq.returned_mem = 0;
			}
			/* fill in request for the thread and kick it off
			 */
			if (cp->memreq.thread_status == 0 && !cp->memreq.returned_mem) {
			    bcopy(opt_data, cp->memreq.comp_opts, len);
			    cp->memreq.cmd = PPPIO_XCOMP;
			    cp->xcomp = *comp;
			    error = cp->memreq.thread_status = EAGAIN;
			    thread_wakeup((vm_offset_t)&cp->memreq.thread_status);
			} else {
			    cp->xstate = cp->memreq.returned_mem;
			    cp->memreq.returned_mem = 0;
			    cp->memreq.thread_status = 0;
			}
		    } else {
			if (cp->rstate) {
			    (*cp->rcomp->decomp_free)(cp->rstate);
			    cp->rstate = NULL;
			}
			if (sizeof (cp->memreq.comp_opts) < len) {
			    printf("can't handle options for compressor %d (%d)\n", opt_data[0],
				opt_data[1]);
			    cp->memreq.thread_status = ENOSR;
			    cp->memreq.returned_mem = 0;
			}
			if (cp->memreq.thread_status == 0 && !cp->memreq.returned_mem) {
			    bcopy(opt_data, cp->memreq.comp_opts, len);
			    cp->memreq.cmd = PPPIO_RCOMP;
			    cp->rcomp = *comp;
			    error = cp->memreq.thread_status = EAGAIN;
			    thread_wakeup((vm_offset_t)&cp->memreq.thread_status);
			} else {
			    cp->rstate = cp->memreq.returned_mem;
			    cp->memreq.returned_mem = 0;
			    cp->memreq.thread_status = 0;
			}
		    }
#endif
		    break;
		}
	    iop->ioc_count = 0;
	    break;

	case PPPIO_GETSTAT:
	    if ((cp->flags & LAST_MOD) == 0) {
		error = -1;	/* let the ppp_ahdl module handle it */
		break;
	    }
	    np = allocb(sizeof(struct ppp_stats), BPRI_HI);
	    if (np == 0) {
		error = ENOSR;
		break;
	    }
	    if (mp->b_cont != 0)
		freemsg(mp->b_cont);
	    mp->b_cont = np;
	    psp = (struct ppp_stats *) np->b_wptr;
	    np->b_wptr += sizeof(struct ppp_stats);
	    iop->ioc_count = sizeof(struct ppp_stats);
	    psp->p = cp->stats;
	    psp->vj = cp->vj_comp.stats;
	    error = 0;
	    break;

	case PPPIO_GETCSTAT:
	    np = allocb(sizeof(struct ppp_comp_stats), BPRI_HI);
	    if (np == 0) {
		error = ENOSR;
		break;
	    }
	    if (mp->b_cont != 0)
		freemsg(mp->b_cont);
	    mp->b_cont = np;
	    csp = (struct ppp_comp_stats *) np->b_wptr;
	    np->b_wptr += sizeof(struct ppp_comp_stats);
	    iop->ioc_count = sizeof(struct ppp_comp_stats);
	    bzero((caddr_t)csp, sizeof(struct ppp_comp_stats));
	    if (cp->xstate != 0)
		(*cp->xcomp->comp_stat)(cp->xstate, &csp->c);
	    if (cp->rstate != 0)
		(*cp->rcomp->decomp_stat)(cp->rstate, &csp->d);
	    error = 0;
	    break;

	case PPPIO_DEBUG:
	    if (iop->ioc_count != sizeof(int))
		break;
	    if (mp->b_cont == 0) {
		DPRINT1("ppp_comp_wput/%d: PPPIO_DEBUG b_cont = 0!\n", cp->unit);
		break;
	    }
	    n = *(int *)mp->b_cont->b_rptr;
	    if (n == PPPDBG_LOG + PPPDBG_COMP) {
		DPRINT1("ppp_comp%d: debug log enabled\n", cp->unit);
		cp->flags |= DBGLOG;
		error = 0;
		iop->ioc_count = 0;
	    } else {
		error = -1;
	    }
	    break;

	case PPPIO_LASTMOD:
	    cp->flags |= LAST_MOD;
	    error = 0;
	    break;

	default:
	    error = -1;
	    break;
	}

	if (error < 0)
	    putnext(q, mp);
	else if (error == 0) {