/*
 * scamper_icmp_resp.c
 *
 * $Id: scamper_icmp_resp.c,v 1.9 2007/05/03 23:25:11 mjl Exp $
 *
 * Copyright (C) 2005-2007 The University of Waikato
 *
 * 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, version 2.
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#include <sys/time.h>
#include <sys/types.h>
#include <sys/socket.h>

#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip_icmp.h>
#include <netinet/ip6.h>
#include <netinet/icmp6.h>

#include <arpa/inet.h>

#if defined(__APPLE__)
#include <stdint.h>
#endif

#include <stdio.h>
#include <string.h>
#include <assert.h>

#include "scamper_addr.h"
#include "scamper_task.h"
#include "scamper_target.h"
#include "scamper_icmp_resp.h"
#include "scamper_debug.h"

#if !defined(ICMP_UNREACH_FILTER_PROHIB)
#if defined(ICMP_UNREACH_ADMIN_PROHIBIT) /* NetBSD */
#define ICMP_UNREACH_FILTER_PROHIB ICMP_UNREACH_ADMIN_PROHIBIT
#else
#define ICMP_UNREACH_FILTER_PROHIB 13
#endif
#endif

#if !defined(ICMP6_DST_UNREACH_BEYONDSCOPE)
#if defined(ICMP6_DST_UNREACH_NOTNEIGHBOR)
#define ICMP6_DST_UNREACH_BEYONDSCOPE ICMP6_DST_UNREACH_NOTNEIGHBOR
#else
#define ICMP6_DST_UNREACH_BEYONDSCOPE 2
#endif
#endif

#ifndef NDEBUG
void scamper_icmp_resp_print(const scamper_icmp_resp_t *ir)
{
  char *type = NULL, tbuf[64];
  char *param = NULL, pbuf[64];
  char addr[64];
  char ip[256];
  char icmp[256];
  char inner_ip[256];
  char inner_transport[256];

  assert(ir->ir_af == AF_INET || ir->ir_af == AF_INET6);

  if(ir->ir_af == AF_INET)
    {
      inet_ntop(AF_INET, &ir->ir_ip_src.v4, addr, sizeof(addr));

      snprintf(ip, sizeof(ip),
	       "from: %s size %d ttl %d tos 0x%02x ipid 0x%04x", addr,
	       ir->ir_ip_size, ir->ir_ip_ttl, ir->ir_ip_tos, ir->ir_ip_id);

      switch(ir->ir_icmp_type)
        {
        case ICMP_UNREACH:
          type = "dest unreach";
          switch(ir->ir_icmp_code)
            {
            case ICMP_UNREACH_NET:
	      param = "code: bad net";
	      break;

            case ICMP_UNREACH_HOST:
              param = "code: bad host";
	      break;

            case ICMP_UNREACH_PROTOCOL:
	      param = "code: bad protocol";
	      break;

            case ICMP_UNREACH_PORT:
              param = "code: bad port";
	      break;

            case ICMP_UNREACH_SRCFAIL:
	      param = "code: src rt failed";
	      break;

            case ICMP_UNREACH_NET_UNKNOWN:
	      param = "code: net unknown";
	      break;

            case ICMP_UNREACH_HOST_UNKNOWN:
	      param = "code: host unknown";
	      break;

            case ICMP_UNREACH_ISOLATED:
	      param = "code: isolated";
	      break;

            case ICMP_UNREACH_NET_PROHIB:
	      param = "code: net prohib";
	      break;

            case ICMP_UNREACH_HOST_PROHIB:
	      param = "code: host prohib";
	      break;

            case ICMP_UNREACH_TOSNET:
	      param = "code: tos net";
	      break;

            case ICMP_UNREACH_TOSHOST:
	      param = "code: tos host";
	      break;

            case ICMP_UNREACH_FILTER_PROHIB:
	      param = "code: admin prohib";
	      break;

            case ICMP_UNREACH_NEEDFRAG:
	      /*
	       * use the type buf to be consistent with the ICMP6
	       * fragmentation required message
	       */
	      snprintf(tbuf, sizeof(tbuf), "need frag: %d", ir->ir_icmp_nhmtu);
	      type = tbuf;
	      break;

            default:
	      snprintf(pbuf, sizeof(pbuf), "code: %d", ir->ir_icmp_code);
	      param = pbuf;
	      break;
            }
          break;

        case ICMP_TIMXCEED:
          type = "time exceeded";
          switch(ir->ir_icmp_code)
            {
            case ICMP_TIMXCEED_INTRANS:
	      param = "code: ttl exp trans";
	      break;

            case ICMP_TIMXCEED_REASS:
	      param = "code: ttl exp reass";
	      break;

            default:
	      snprintf(pbuf, sizeof(pbuf), "code: %d", ir->ir_icmp_code);
	      param = pbuf;
	      break;
            }
          break;

	case ICMP_ECHOREPLY:
	  type = "echo reply";
	  snprintf(pbuf, sizeof(pbuf), "id: %d seq: %d",
		   ir->ir_icmp_id, ir->ir_icmp_seq);
	  param = pbuf;
	  break;
        }
    }
  else /* if(ir->ir_af == AF_INET6) */
    {
      inet_ntop(AF_INET6, &ir->ir_ip_src.v6, addr, sizeof(addr));

      snprintf(ip, sizeof(ip), "from: %s size %d hlim %d", addr,
	       ir->ir_ip_size, ir->ir_ip_hlim);

      switch(ir->ir_icmp_type)
        {
        case ICMP6_DST_UNREACH:
          type = "dest unreach";
          switch(ir->ir_icmp_code)
            {
            case ICMP6_DST_UNREACH_NOROUTE:
	      param = "code: no route";
	      break;

            case ICMP6_DST_UNREACH_ADMIN:
	      param = "code: admin prohib";
	      break;

            case ICMP6_DST_UNREACH_BEYONDSCOPE:
	      param = "code: beyond scope";
	      break;

            case ICMP6_DST_UNREACH_ADDR:
	      param = "code: addr unreach";
	      break;

            case ICMP6_DST_UNREACH_NOPORT:
	      param = "code: port unreach";
	      break;

            default:
	      snprintf(pbuf, sizeof(pbuf), "code: %d", ir->ir_icmp_code);
	      param = pbuf;
	      break;
            }
          break;

        case ICMP6_TIME_EXCEEDED:
          type = "time exceeded";
          switch(ir->ir_icmp_code)
            {
            case ICMP6_TIME_EXCEED_TRANSIT:
	      param = "code: ttl exp trans";
	      break;

            case ICMP6_TIME_EXCEED_REASSEMBLY:
	      param = "code: ttl exp reass";
	      break;

            default:
	      snprintf(pbuf, sizeof(pbuf), "code: %d", ir->ir_icmp_code);
	      param = pbuf;
	      break;
            }
          break;

	case ICMP6_PACKET_TOO_BIG:
	  snprintf(tbuf, sizeof(tbuf), "need frag: %d", ir->ir_icmp_nhmtu);
	  type = tbuf;
	  break;

	case ICMP6_ECHO_REPLY:
	  type = "echo reply";
	  snprintf(pbuf, sizeof(pbuf), "id: %d seq: %d",
		   ir->ir_icmp_id, ir->ir_icmp_seq);
	  param = pbuf;
	  break;
        } 
    }

  if(type == NULL)
    {
      snprintf(icmp, sizeof(icmp), "icmp: %d code: %d",
	       ir->ir_icmp_type, ir->ir_icmp_code);
    }
  else if(param == NULL)
    {
      snprintf(icmp, sizeof(icmp), "icmp: %s", type);
    }
  else
    {
      snprintf(icmp, sizeof(icmp), "icmp: %s %s", type, param);
    }

  if(ir->ir_flags & SCAMPER_ICMP_RESP_FLAG_INNER_IP)
    {
      if(ir->ir_af == AF_INET)
	{
	  inet_ntop(AF_INET, &ir->ir_inner_ip_dst.v4, addr, sizeof(addr));
	  snprintf(inner_ip, sizeof(inner_ip),
		   " to: %s size %d ttl %d tos 0x%02x ipid 0x%04x", addr,
		   ir->ir_inner_ip_size, ir->ir_inner_ip_ttl,
		   ir->ir_inner_ip_tos, ir->ir_inner_ip_id);
	}
      else /* if(ir->ir_af == AF_INET6) */
	{
	  inet_ntop(AF_INET6, &ir->ir_inner_ip_dst.v6, addr, sizeof(addr));
	  snprintf(inner_ip, sizeof(inner_ip),
		   " to: %s size %d hlim %d flow 0x%05x", addr,
		   ir->ir_inner_ip_size, ir->ir_inner_ip_hlim,
		   ir->ir_inner_ip_flow);
	}

      switch(ir->ir_inner_ip_proto)
	{
	case IPPROTO_UDP:
	  snprintf(inner_transport, sizeof(inner_transport),
		   " proto: UDP sport %d dport %d",
		   ir->ir_inner_udp_sport, ir->ir_inner_udp_dport);
	  break;

	case IPPROTO_ICMP:
	case IPPROTO_ICMPV6:
	  snprintf(inner_transport, sizeof(inner_transport),
		   " proto: ICMP type %d code %d id %04x seq %04x",
		   ir->ir_inner_icmp_type, ir->ir_inner_icmp_code,
		   ir->ir_inner_icmp_id, ir->ir_inner_icmp_seq);
	  break;

	case IPPROTO_TCP:
	  snprintf(inner_transport, sizeof(inner_transport),
		   " proto: TCP sport %d dport %d seq %08x",
		   ir->ir_inner_tcp_sport, ir->ir_inner_tcp_dport,
		   ir->ir_inner_tcp_seq);
	  break;

	default:
	  inner_transport[0] = '\0';
	  break;
	}
    }
  else
    {
      inner_ip[0] = '\0';
      inner_transport[0] = '\0';
    }

  scamper_debug(NULL, "%s %s%s%s", ip, icmp, inner_ip, inner_transport);
  return;
}
#endif

int scamper_icmp_resp_src(scamper_icmp_resp_t *resp, scamper_addr_t *addr)
{
  if(resp->ir_af == AF_INET)
    {
      addr->type = SCAMPER_ADDR_TYPE_IPV4;
      addr->addr = &resp->ir_ip_src.v4;
      return 0;
    }
  if(resp->ir_af == AF_INET6)
    {
      addr->type = SCAMPER_ADDR_TYPE_IPV6;
      addr->addr = &resp->ir_ip_src.v6;
      return 0;
    }
  return -1;
}

int scamper_icmp_resp_inner_dst(scamper_icmp_resp_t *resp,scamper_addr_t *addr)
{
  if(resp->ir_af == AF_INET)
    {
      addr->type = SCAMPER_ADDR_TYPE_IPV4;
      addr->addr = &resp->ir_inner_ip_dst.v4;
      return 0;
    }
  if(resp->ir_af == AF_INET6)
    {
      addr->type = SCAMPER_ADDR_TYPE_IPV6;
      addr->addr = &resp->ir_inner_ip_dst.v6;
      return 0;
    }
  return -1;
}

void scamper_icmp_resp_handle(scamper_icmp_resp_t *resp)
{
  scamper_target_t  *target;
  scamper_task_t    *task;
  scamper_addr_t     addr;

  /* the target address of the probe is embedded in the response */
  if(SCAMPER_ICMP_RESP_IS_TTL_EXP(resp) ||
     SCAMPER_ICMP_RESP_IS_UNREACH(resp) ||
     SCAMPER_ICMP_RESP_IS_PACKET_TOO_BIG(resp))
    {
      /* not able to handle this response, drop it */
      if(!SCAMPER_ICMP_RESP_INNER_IS_SET(resp))
	{
	  return;
	}

      if(scamper_icmp_resp_inner_dst(resp, &addr) != 0)
	{
	  return;
	}
    }
  else if(SCAMPER_ICMP_RESP_IS_ECHO_REPLY(resp))
    {
      if(scamper_icmp_resp_src(resp, &addr) != 0)
	{
	  return;
	}
    }
  else
    {
      return;
    }

  if((target = scamper_target_find(&addr)) == NULL)
    {
      return;
    }

  task = target->task;

  if(task->funcs->handle_icmp != NULL)
    {
      task->funcs->handle_icmp(task, resp);
    }

  return;
}