/*-
 * Copyright (c) 1997 Brian Somers <brian@Awfulhak.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON 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 ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	$Id: server.c,v 1.16.2.17 1998/04/28 01:25:41 brian Exp $
 */

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <sys/un.h>

#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <sys/stat.h>
#include <termios.h>
#include <unistd.h>

#include "mbuf.h"
#include "log.h"
#include "defs.h"
#include "descriptor.h"
#include "server.h"
#include "id.h"
#include "prompt.h"
#include "timer.h"
#include "lqr.h"
#include "hdlc.h"
#include "fsm.h"
#include "lcp.h"
#include "ccp.h"
#include "throughput.h"
#include "link.h"
#include "mp.h"
#include "iplist.h"
#include "slcompress.h"
#include "ipcp.h"
#include "filter.h"
#include "bundle.h"

static int
server_UpdateSet(struct descriptor *d, fd_set *r, fd_set *w, fd_set *e, int *n)
{
  struct server *s = descriptor2server(d);

  if (r && s->fd >= 0) {
    if (*n < s->fd + 1)
      *n = s->fd + 1;
    FD_SET(s->fd, r);
    return 1;
  }
  return 0;
}

static int
server_IsSet(struct descriptor *d, const fd_set *fdset)
{
  struct server *s = descriptor2server(d);
  return s->fd >= 0 && FD_ISSET(s->fd, fdset);
}

#define IN_SIZE sizeof(struct sockaddr_in)
#define UN_SIZE sizeof(struct sockaddr_in)
#define ADDRSZ (IN_SIZE > UN_SIZE ? IN_SIZE : UN_SIZE)

static void
server_Read(struct descriptor *d, struct bundle *bundle, const fd_set *fdset)
{
  struct server *s = descriptor2server(d);
  char hisaddr[ADDRSZ];
  struct sockaddr *sa = (struct sockaddr *)hisaddr;
  struct sockaddr_in *in = (struct sockaddr_in *)hisaddr;
  int ssize = ADDRSZ, wfd;
  struct prompt *p;

  wfd = accept(s->fd, sa, &ssize);
  if (wfd < 0) {
    log_Printf(LogERROR, "server_Read: accept(): %s\n", strerror(errno));
    return;
  }

  switch (sa->sa_family) {
    case AF_LOCAL:
      log_Printf(LogPHASE, "Connected to local client.\n");
      break;

    case AF_INET:
      if (ntohs(in->sin_port) < 1024) {
        log_Printf(LogALERT, "Rejected client connection from %s:%u"
                  "(invalid port number) !\n",
                  inet_ntoa(in->sin_addr), ntohs(in->sin_port));
        close(wfd);
        return;
      }
      log_Printf(LogPHASE, "Connected to client from %s:%u\n",
                inet_ntoa(in->sin_addr), in->sin_port);
      break;

    default:
      write(wfd, "Unrecognised access !\n", 22);
      close(wfd);
      return;
  }

  if ((p = prompt_Create(s, bundle, wfd)) == NULL) {
    write(wfd, "Connection refused.\n", 20);
    close(wfd);
  } else {
    switch (sa->sa_family) {
      case AF_LOCAL:
        p->src.type = "local";
        strncpy(p->src.from, s->rm, sizeof p->src.from - 1);
        p->src.from[sizeof p->src.from - 1] = '\0';
        break;
      case AF_INET:
        p->src.type = "tcp";
        snprintf(p->src.from, sizeof p->src.from, "%s:%u",
                 inet_ntoa(in->sin_addr), in->sin_port);
        break;
    }
    prompt_TtyCommandMode(p);
    prompt_Required(p);
  }
}

static void
server_Write(struct descriptor *d, struct bundle *bundle, const fd_set *fdset)
{
  /* We never want to write here ! */
  log_Printf(LogERROR, "server_Write: Internal error: Bad call !\n");
}

struct server server = {
  {
    SERVER_DESCRIPTOR,
    NULL,
    server_UpdateSet,
    server_IsSet,
    server_Read,
    server_Write
  },
  -1
};

int
server_LocalOpen(struct bundle *bundle, const char *name, mode_t mask)
{
  int s;

  if (server.rm && !strcmp(server.rm, name)) {
    if (chmod(server.rm, mask))
      log_Printf(LogERROR, "Local: chmod: %s\n", strerror(errno));
    return 0;
  }

  memset(&server.ifsun, '\0', sizeof server.ifsun);
  server.ifsun.sun_len = strlen(name);
  if (server.ifsun.sun_len > sizeof server.ifsun.sun_path - 1) {
    log_Printf(LogERROR, "Local: %s: Path too long\n", name);
    return 2;
  }
  server.ifsun.sun_family = AF_LOCAL;
  strcpy(server.ifsun.sun_path, name);

  s = ID0socket(PF_LOCAL, SOCK_STREAM, 0);
  if (s < 0) {
    log_Printf(LogERROR, "Local: socket: %s\n", strerror(errno));
    return 3;
  }
  setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &s, sizeof s);
  if (mask != (mode_t)-1)
    mask = umask(mask);
  if (bind(s, (struct sockaddr *)&server.ifsun, sizeof server.ifsun) < 0) {
    if (mask != (mode_t)-1)
      umask(mask);
    log_Printf(LogWARN, "Local: bind: %s\n", strerror(errno));
    close(s);
    return 4;
  }
  if (mask != (mode_t)-1)
    umask(mask);
  if (listen(s, 5) != 0) {
    log_Printf(LogERROR, "Local: Unable to listen to socket - BUNDLE overload?\n");
    close(s);
    ID0unlink(name);
    return 5;
  }
  server_Close(bundle);
  server.fd = s;
  server.rm = server.ifsun.sun_path;
  log_Printf(LogPHASE, "Listening at local socket %s.\n", name);
  return 0;
}

int
server_TcpOpen(struct bundle *bundle, int port)
{
  struct sockaddr_in ifsin;
  int s;

  if (server.port == port)
    return 0;

  s = ID0socket(PF_INET, SOCK_STREAM, 0);
  if (s < 0) {
    log_Printf(LogERROR, "Tcp: socket: %s\n", strerror(errno));
    return 7;
  }
  memset(&ifsin, '\0', sizeof ifsin);
  ifsin.sin_family = AF_INET;
  ifsin.sin_addr.s_addr = INADDR_ANY;
  ifsin.sin_port = htons(port);
  setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &s, sizeof s);
  if (bind(s, (struct sockaddr *)&ifsin, sizeof ifsin) < 0) {
    log_Printf(LogWARN, "Tcp: bind: %s\n", strerror(errno));
    close(s);
    return 8;
  }
  if (listen(s, 5) != 0) {
    log_Printf(LogERROR, "Tcp: Unable to listen to socket - BUNDLE overload?\n");
    close(s);
    return 9;
  }
  server_Close(bundle);
  server.fd = s;
  server.port = port;
  log_Printf(LogPHASE, "Listening at port %d.\n", port);
  return 0;
}

int
server_Close(struct bundle *bundle)
{
  if (server.fd >= 0) {
    close(server.fd);
    if (server.rm) {
      ID0unlink(server.rm);
      server.rm = NULL;
    }
    server.fd = -1;
    server.port = 0;
    /* Drop associated prompts */
    bundle_DelPromptDescriptors(bundle, &server);
    return 1;
  }
  return 0;
}