/* 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 "std-includes.h"
#include "rfcnb-priv.h"
#include "rfcnb-util.h"
#include "rfcnb-io.h"
#include <sys/uio.h>
#include <sys/signal.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 */
#ifndef SA_RESTART
  struct sigvec invec, outvec;
#else
  struct sigaction inact, outact;
#endif

  RFCNB_Timeout = seconds;

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

#ifndef SA_RESTART
    invec.sv_handler = (void (*)())rfcnb_alarm;
    invec.sv_mask = 0;
    invec.sv_flags = SV_INTERRUPT;

    if (sigvec(SIGALRM, &invec, &outvec)  < 0)
      return(-1);
#else
    inact.sa_handler = (void (*)())rfcnb_alarm;
    memset(&(inact.sa_mask), 0, sizeof(inact.sa_mask));
    inact.sa_flags = 0;    /* Don't restart */

    if (sigaction(SIGALRM, &inact, &outact) < 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 -> err = 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));
}