rfcnb-io.c

一个功能非常全面的代理服务器源代码程序,

/* UNIX RFCNB (RFC1001/RFC1002) NEtBIOS implementation
 * 
 * Version 1.0
 * RFCNB IO Routines ...
 * 
 * Copyright (C) Richard Sharpe 1996
 * 
 */

/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
/* #include <features.h> */
#include "config.h"
#include "std-includes.h"
#include "rfcnb-priv.h"
#include "rfcnb-util.h"
#include "rfcnb-io.h"
#include <sys/uio.h>
#include <sys/signal.h>
#include <string.h>

int RFCNB_Timeout = 0;		/* Timeout in seconds ... */

void
rfcnb_alarm(int sig)
{

    fprintf(stderr, "IO Timed out ...\n");

}

/* Set timeout value and setup signal handling */

int
RFCNB_Set_Timeout(int seconds)
{
    /* If we are on a Bezerkeley system, use sigvec, else sigaction */
#if HAVE_SIGACTION
    struct sigaction inact, outact;
#else
    struct sigvec invec, outvec;
#endif

    RFCNB_Timeout = seconds;

    if (RFCNB_Timeout > 0) {	/* Set up handler to ignore but not restart */

#if HAVE_SIGACTION
	inact.sa_handler = (void (*)()) rfcnb_alarm;
	sigemptyset(&inact.sa_mask);
	inact.sa_flags = 0;	/* Don't restart */

	if (sigaction(SIGALRM, &inact, &outact) < 0)
	    return (-1);
#else
	invec.sv_handler = (void (*)()) rfcnb_alarm;
	invec.sv_mask = 0;
	invec.sv_flags = SV_INTERRUPT;

	if (sigvec(SIGALRM, &invec, &outvec) < 0)
	    return (-1);
#endif

    }
    return (0);

}

/* Discard the rest of an incoming packet as we do not have space for it
 * in the buffer we allocated or were passed ...                         */

int
RFCNB_Discard_Rest(struct RFCNB_Con *con, int len)
{
    char temp[100];		/* Read into here */
    int rest, this_read, bytes_read;

    /* len is the amount we should read */

#ifdef RFCNB_DEBUG
    fprintf(stderr, "Discard_Rest called to discard: %i\n", len);
#endif

    rest = len;

    while (rest > 0) {

	this_read = (rest > sizeof(temp) ? sizeof(temp) : rest);

	bytes_read = read(con->fd, temp, this_read);

	if (bytes_read <= 0) {	/* Error so return */

	    if (bytes_read < 0)
		RFCNB_errno = RFCNBE_BadRead;
	    else
		RFCNB_errno = RFCNBE_ConGone;

	    RFCNB_saved_errno = errno;
	    return (RFCNBE_Bad);

	}
	rest = rest - bytes_read;

    }

    return (0);

}


/* Send an RFCNB packet to the connection.
 * 
 * We just send each of the blocks linked together ... 
 * 
 * If we can, try to send it as one iovec ... 
 * 
 */

int
RFCNB_Put_Pkt(struct RFCNB_Con *con, struct RFCNB_Pkt *pkt, int len)
{
    int len_sent, tot_sent, this_len;
    struct RFCNB_Pkt *pkt_ptr;
    char *this_data;
    int i;
    struct iovec io_list[10];	/* We should never have more      */
    /* If we do, this will blow up ... */

    /* Try to send the data ... We only send as many bytes as len claims */
    /* We should try to stuff it into an IOVEC and send as one write     */


    pkt_ptr = pkt;
    len_sent = tot_sent = 0;	/* Nothing sent so far */
    i = 0;

    while ((pkt_ptr != NULL) & (i < 10)) {	/* Watch that magic number! */

	this_len = pkt_ptr->len;
	this_data = pkt_ptr->data;
	if ((tot_sent + this_len) > len)
	    this_len = len - tot_sent;	/* Adjust so we don't send too much */

	/* Now plug into the iovec ... */

	io_list[i].iov_len = this_len;
	io_list[i].iov_base = this_data;
	i++;

	tot_sent += this_len;

	if (tot_sent == len)
	    break;		/* Let's not send too much */

	pkt_ptr = pkt_ptr->next;

    }

#ifdef RFCNB_DEBUG
    fprintf(stderr, "Frags = %i, tot_sent = %i\n", i, tot_sent);
#endif

    /* Set up an alarm if timeouts are set ... */

    if (RFCNB_Timeout > 0)
	alarm(RFCNB_Timeout);

    if ((len_sent = writev(con->fd, io_list, i)) < 0) {		/* An error */

	con->rfc_errno = errno;
	if (errno == EINTR)	/* We were interrupted ... */
	    RFCNB_errno = RFCNBE_Timeout;
	else
	    RFCNB_errno = RFCNBE_BadWrite;
	RFCNB_saved_errno = errno;
	return (RFCNBE_Bad);

    }
    if (len_sent < tot_sent) {	/* Less than we wanted */
	if (errno == EINTR)	/* We were interrupted */
	    RFCNB_errno = RFCNBE_Timeout;
	else
	    RFCNB_errno = RFCNBE_BadWrite;
	RFCNB_saved_errno = errno;
	return (RFCNBE_Bad);
    }
    if (RFCNB_Timeout > 0)
	alarm(0);		/* Reset that sucker */

#ifdef RFCNB_DEBUG

    fprintf(stderr, "Len sent = %i ...\n", len_sent);
    RFCNB_Print_Pkt(stderr, "sent", pkt, len_sent);	/* Print what send ... */

#endif

    return (len_sent);

}

/* Read an RFCNB packet off the connection. 
 * 
 * We read the first 4 bytes, that tells us the length, then read the
 * rest. We should implement a timeout, but we don't just yet 
 * 
 */


int
RFCNB_Get_Pkt(struct RFCNB_Con *con, struct RFCNB_Pkt *pkt, int len)
{
    int read_len, pkt_len;
    char hdr[RFCNB_Pkt_Hdr_Len];	/* Local space for the header */
    struct RFCNB_Pkt *pkt_frag;
    int more, this_time, offset, frag_len, this_len;
    BOOL seen_keep_alive = TRUE;

    /* Read that header straight into the buffer */

    if (len < RFCNB_Pkt_Hdr_Len) {	/* What a bozo */

#ifdef RFCNB_DEBUG
	fprintf(stderr, "Trying to read less than a packet:");
	perror("");
#endif
	RFCNB_errno = RFCNBE_BadParam;
	return (RFCNBE_Bad);

    }
    /* We discard keep alives here ... */

    if (RFCNB_Timeout > 0)
	alarm(RFCNB_Timeout);

    while (seen_keep_alive) {

	if ((read_len = read(con->fd, hdr, sizeof(hdr))) < 0) {		/* Problems */
#ifdef RFCNB_DEBUG
	    fprintf(stderr, "Reading the packet, we got:");
	    perror("");
#endif
	    if (errno == EINTR)
		RFCNB_errno = RFCNBE_Timeout;
	    else
		RFCNB_errno = RFCNBE_BadRead;
	    RFCNB_saved_errno = errno;
	    return (RFCNBE_Bad);

	}
	/* Now we check out what we got */

	if (read_len == 0) {	/* Connection closed, send back eof?  */

#ifdef RFCNB_DEBUG
	    fprintf(stderr, "Connection closed reading\n");
#endif

	    if (errno == EINTR)
		RFCNB_errno = RFCNBE_Timeout;
	    else
		RFCNB_errno = RFCNBE_ConGone;
	    RFCNB_saved_errno = errno;
	    return (RFCNBE_Bad);

	}
	if (RFCNB_Pkt_Type(hdr) == RFCNB_SESSION_KEEP_ALIVE) {

#ifdef RFCNB_DEBUG
	    fprintf(stderr, "RFCNB KEEP ALIVE received\n");
#endif

	} else {
	    seen_keep_alive = FALSE;
	}

    }

    /* What if we got less than or equal to a hdr size in bytes? */

    if (read_len < sizeof(hdr)) {	/* We got a small packet */

	/* Now we need to copy the hdr portion we got into the supplied packet */

	memcpy(pkt->data, hdr, read_len);	/*Copy data */

#ifdef RFCNB_DEBUG
	RFCNB_Print_Pkt(stderr, "rcvd", pkt, read_len);
#endif

	return (read_len);

    }
    /* Now, if we got at least a hdr size, alloc space for rest, if we need it */

    pkt_len = RFCNB_Pkt_Len(hdr);

#ifdef RFCNB_DEBUG
    fprintf(stderr, "Reading Pkt: Length = %i\n", pkt_len);
#endif

    /* Now copy in the hdr */

    memcpy(pkt->data, hdr, sizeof(hdr));

    /* Get the rest of the packet ... first figure out how big our buf is? */
    /* And make sure that we handle the fragments properly ... Sure should */
    /* use an iovec ...                                                    */

    if (len < pkt_len)		/* Only get as much as we have space for */
	more = len - RFCNB_Pkt_Hdr_Len;
    else
	more = pkt_len;

    this_time = 0;

    /* We read for each fragment ... */

    if (pkt->len == read_len) {	/* If this frag was exact size */
	pkt_frag = pkt->next;	/* Stick next lot in next frag */
	offset = 0;		/* then we start at 0 in next  */
    } else {
	pkt_frag = pkt;		/* Otherwise use rest of this frag */
	offset = RFCNB_Pkt_Hdr_Len;	/* Otherwise skip the header       */
    }

    frag_len = pkt_frag->len;

    if (more <= frag_len)	/* If len left to get less than frag space */
	this_len = more;	/* Get the rest ...                        */
    else
	this_len = frag_len - offset;

    while (more > 0) {

	if ((this_time = read(con->fd, (pkt_frag->data) + offset, this_len)) <= 0) {	/* Problems */

	    if (errno == EINTR) {

		RFCNB_errno = RFCNB_Timeout;

	    } else {
		if (this_time < 0)
		    RFCNB_errno = RFCNBE_BadRead;
		else
		    RFCNB_errno = RFCNBE_ConGone;
	    }

	    RFCNB_saved_errno = errno;
	    return (RFCNBE_Bad);

	}
#ifdef RFCNB_DEBUG
	fprintf(stderr, "Frag_Len = %i, this_time = %i, this_len = %i, more = %i\n", frag_len,
	    this_time, this_len, more);
#endif

	read_len = read_len + this_time;	/* How much have we read ... */

	/* Now set up the next part */

	if (pkt_frag->next == NULL)
	    break;		/* That's it here */

	pkt_frag = pkt_frag->next;
	this_len = pkt_frag->len;
	offset = 0;

	more = more - this_time;

    }

#ifdef RFCNB_DEBUG
    fprintf(stderr, "Pkt Len = %i, read_len = %i\n", pkt_len, read_len);
    RFCNB_Print_Pkt(stderr, "rcvd", pkt, read_len + sizeof(hdr));
#endif

    if (read_len < (pkt_len + sizeof(hdr))) {	/* Discard the rest */

	return (RFCNB_Discard_Rest(con, (pkt_len + sizeof(hdr)) - read_len));

    }
    if (RFCNB_Timeout > 0)
	alarm(0);		/* Reset that sucker */

    return (read_len + sizeof(RFCNB_Hdr));
}