/*
 * OSPF network related functions
 *   Copyright (C) 1999 Toshiaki Takada
 *
 * This file is part of GNU Zebra.
 *
 * GNU Zebra 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, or (at your option) any
 * later version.
 *
 * GNU Zebra 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 GNU Zebra; see the file COPYING.  If not, write to the Free
 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
 * 02111-1307, USA.
 */

#include <zebra.h>

#include "thread.h"
#include "linklist.h"
#include "prefix.h"
#include "if.h"
#include "sockunion.h"
#include "log.h"
#include "sockopt.h"
#include "privs.h"

extern struct zebra_privs_t ospfd_privs;

#include "ospfd/ospfd.h"
#include "ospfd/ospf_network.h"
#include "ospfd/ospf_interface.h"
#include "ospfd/ospf_asbr.h"
#include "ospfd/ospf_lsa.h"
#include "ospfd/ospf_lsdb.h"
#include "ospfd/ospf_neighbor.h"
#include "ospfd/ospf_packet.h"
#include "ospfd/ospf_dump.h"


/* Join to the OSPF ALL SPF ROUTERS multicast group. */
int
ospf_if_add_allspfrouters (struct ospf *top, struct prefix *p,
			   unsigned int ifindex)
{
  int ret;
  
  ret = setsockopt_multicast_ipv4 (top->fd, IP_ADD_MEMBERSHIP,
                                   p->u.prefix4, htonl (OSPF_ALLSPFROUTERS),
                                   ifindex);
  if (ret < 0)
    zlog_warn ("can't setsockopt IP_ADD_MEMBERSHIP (fd %d, addr %s, "
	       "ifindex %u, AllSPFRouters): %s; perhaps a kernel limit "
	       "on # of multicast group memberships has been exceeded?",
               top->fd, inet_ntoa(p->u.prefix4), ifindex, safe_strerror(errno));
  else
    zlog_debug ("interface %s [%u] join AllSPFRouters Multicast group.",
	       inet_ntoa (p->u.prefix4), ifindex);

  return ret;
}

int
ospf_if_drop_allspfrouters (struct ospf *top, struct prefix *p,
			    unsigned int ifindex)
{
  int ret;

  ret = setsockopt_multicast_ipv4 (top->fd, IP_DROP_MEMBERSHIP,
                                   p->u.prefix4, htonl (OSPF_ALLSPFROUTERS),
                                   ifindex);
  if (ret < 0)
    zlog_warn ("can't setsockopt IP_DROP_MEMBERSHIP (fd %d, addr %s, "
	       "ifindex %u, AllSPFRouters): %s",
               top->fd, inet_ntoa(p->u.prefix4), ifindex, safe_strerror(errno));
  else
    zlog_debug ("interface %s [%u] leave AllSPFRouters Multicast group.",
	        inet_ntoa (p->u.prefix4), ifindex);

  return ret;
}

/* Join to the OSPF ALL Designated ROUTERS multicast group. */
int
ospf_if_add_alldrouters (struct ospf *top, struct prefix *p, unsigned int
			 ifindex)
{
  int ret;

  ret = setsockopt_multicast_ipv4 (top->fd, IP_ADD_MEMBERSHIP,
                                   p->u.prefix4, htonl (OSPF_ALLDROUTERS),
                                   ifindex);
  if (ret < 0)
    zlog_warn ("can't setsockopt IP_ADD_MEMBERSHIP (fd %d, addr %s, "
	       "ifindex %u, AllDRouters): %s; perhaps a kernel limit "
	       "on # of multicast group memberships has been exceeded?",
               top->fd, inet_ntoa(p->u.prefix4), ifindex, safe_strerror(errno));
  else
    zlog_debug ("interface %s [%u] join AllDRouters Multicast group.",
	        inet_ntoa (p->u.prefix4), ifindex);

  return ret;
}

int
ospf_if_drop_alldrouters (struct ospf *top, struct prefix *p, unsigned int
			  ifindex)
{
  int ret;

  ret = setsockopt_multicast_ipv4 (top->fd, IP_DROP_MEMBERSHIP,
                                   p->u.prefix4, htonl (OSPF_ALLDROUTERS),
                                   ifindex);
  if (ret < 0)
    zlog_warn ("can't setsockopt IP_DROP_MEMBERSHIP (fd %d, addr %s, "
	       "ifindex %u, AllDRouters): %s",
               top->fd, inet_ntoa(p->u.prefix4), ifindex, safe_strerror(errno));
  else
    zlog_debug ("interface %s [%u] leave AllDRouters Multicast group.",
	        inet_ntoa (p->u.prefix4), ifindex);

  return ret;
}

int
ospf_if_ipmulticast (struct ospf *top, struct prefix *p, unsigned int ifindex)
{
  u_char val;
  int ret, len;
  
  val = 0;
  len = sizeof (val);
  
  /* Prevent receiving self-origined multicast packets. */
  ret = setsockopt (top->fd, IPPROTO_IP, IP_MULTICAST_LOOP, (void *)&val, len);
  if (ret < 0)
    zlog_warn ("can't setsockopt IP_MULTICAST_LOOP(0) for fd %d: %s",
	       top->fd, safe_strerror(errno));
  
  /* Explicitly set multicast ttl to 1 -- endo. */
  val = 1;
  ret = setsockopt (top->fd, IPPROTO_IP, IP_MULTICAST_TTL, (void *)&val, len);
  if (ret < 0)
    zlog_warn ("can't setsockopt IP_MULTICAST_TTL(1) for fd %d: %s",
	       top->fd, safe_strerror (errno));

  ret = setsockopt_multicast_ipv4 (top->fd, IP_MULTICAST_IF,
                                   p->u.prefix4, 0, ifindex);
  if (ret < 0)
    zlog_warn("can't setsockopt IP_MULTICAST_IF(fd %d, addr %s, "
	      "ifindex %u): %s",
	      top->fd, inet_ntoa(p->u.prefix4), ifindex, safe_strerror(errno));

  return ret;
}

int
ospf_sock_init (void)
{
  int ospf_sock;
  int ret, hincl = 1;

  if ( ospfd_privs.change (ZPRIVS_RAISE) )
    zlog_err ("ospf_sock_init: could not raise privs, %s",
               safe_strerror (errno) );
    
  ospf_sock = socket (AF_INET, SOCK_RAW, IPPROTO_OSPFIGP);
  if (ospf_sock < 0)
    {
      int save_errno = errno;
      if ( ospfd_privs.change (ZPRIVS_LOWER) )
        zlog_err ("ospf_sock_init: could not lower privs, %s",
                   safe_strerror (errno) );
      zlog_err ("ospf_read_sock_init: socket: %s", safe_strerror (save_errno));
      exit(1);
    }
    
#ifdef IP_HDRINCL
  /* we will include IP header with packet */
  ret = setsockopt (ospf_sock, IPPROTO_IP, IP_HDRINCL, &hincl, sizeof (hincl));
  if (ret < 0)
    {
      int save_errno = errno;
      if ( ospfd_privs.change (ZPRIVS_LOWER) )
        zlog_err ("ospf_sock_init: could not lower privs, %s",
                   safe_strerror (errno) );
      zlog_warn ("Can't set IP_HDRINCL option for fd %d: %s",
      		 ospf_sock, safe_strerror(save_errno));
    }
#elif defined (IPTOS_PREC_INTERNETCONTROL)
#warning "IP_HDRINCL not available on this system"
#warning "using IPTOS_PREC_INTERNETCONTROL"
  ret = setsockopt_ipv4_tos(ospf_sock, IPTOS_PREC_INTERNETCONTROL);
  if (ret < 0)
    {
      int save_errno = errno;
      if ( ospfd_privs.change (ZPRIVS_LOWER) )
        zlog_err ("ospf_sock_init: could not lower privs, %s",
                   safe_strerror (errno) );
      zlog_warn ("can't set sockopt IP_TOS %d to socket %d: %s",
      		 tos, ospf_sock, safe_strerror(save_errno));
      close (ospf_sock);	/* Prevent sd leak. */
      return ret;
    }
#else /* !IPTOS_PREC_INTERNETCONTROL */
#warning "IP_HDRINCL not available, nor is IPTOS_PREC_INTERNETCONTROL"
  zlog_warn ("IP_HDRINCL option not available");
#endif /* IP_HDRINCL */

  ret = setsockopt_ifindex (AF_INET, ospf_sock, 1);

  if (ret < 0)
     zlog_warn ("Can't set pktinfo option for fd %d", ospf_sock);

  if (ospfd_privs.change (ZPRIVS_LOWER))
    {
      zlog_err ("ospf_sock_init: could not lower privs, %s",
               safe_strerror (errno) );
    }
 
  return ospf_sock;
}

void
ospf_adjust_sndbuflen (struct ospf * ospf, int buflen)
{
  int ret, newbuflen;
  /* Check if any work has to be done at all. */
  if (ospf->maxsndbuflen >= buflen)
    return;
  if (IS_DEBUG_OSPF (zebra, ZEBRA_INTERFACE))
    zlog_debug ("%s: adjusting OSPF send buffer size to %d",
      __func__, buflen);
  if (ospfd_privs.change (ZPRIVS_RAISE))
    zlog_err ("%s: could not raise privs, %s", __func__,
      safe_strerror (errno));
  /* Now we try to set SO_SNDBUF to what our caller has requested
   * (the MTU of a newly added interface). However, if the OS has
   * truncated the actual buffer size to somewhat less size, try
   * to detect it and update our records appropriately. The OS
   * may allocate more buffer space, than requested, this isn't
   * a error.
   */
  ret = setsockopt_so_sendbuf (ospf->fd, buflen);
  newbuflen = getsockopt_so_sendbuf (ospf->fd);
  if (ret < 0 || newbuflen < buflen)
    zlog_warn ("%s: tried to set SO_SNDBUF to %d, but got %d",
      __func__, buflen, newbuflen);
  if (newbuflen >= 0)
    ospf->maxsndbuflen = newbuflen;
  else
    zlog_warn ("%s: failed to get SO_SNDBUF", __func__);
  if (ospfd_privs.change (ZPRIVS_LOWER))
    zlog_err ("%s: could not lower privs, %s", __func__,
      safe_strerror (errno));
}