/* * nut-route.c - gnutella routing table implementation * * Copyright (C) 2000 Stefan Jahn <stefan@lkcc.org> * * This 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. *  * This software 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 package; see the file COPYING.  If not, write to * the Free Software Foundation, Inc., 59 Temple Place - Suite 330, * Boston, MA 02111-1307, USA.   * * $Id: nut-route.c,v 1.19 2001/08/01 10:16:23 ela Exp $ * */#if HAVE_CONFIG_H# include <config.h>#endif#if ENABLE_GNUTELLA#define _GNU_SOURCE#include <stdio.h>#include <stdlib.h>#include <string.h>#include <ctype.h>#ifdef __MINGW32__# include <winsock2.h>#endif#include "libserveez.h"#include "gnutella.h"#include "nut-route.h"#include "nut-core.h"/* * This function canonizes gnutella queries. Thus we prevent the network * from unpatient users and often repeated queries. */static intnut_canonize_query (nut_config_t *cfg, char *query){  char *key, *p, *extract;  time_t t;  int ret = 0;  /* not a valid query ? */  if (!*query)    return -1;  /* extract alphanumerics only and pack them together as lowercase */  key = extract = p = svz_strdup (query);  while (*p)    {      if (isalnum ((svz_uint8_t) *p)) 	*extract++ = (char) (isupper ((svz_uint8_t) *p) ? 			     tolower ((svz_uint8_t) *p) : *p);      p++;    }  *extract = '\0';  /* check if it is in the recent query hash */  if ((t = (time_t) (long) svz_hash_get (cfg->query, key)) != 0)    {      if (time (NULL) - t < NUT_QUERY_TOO_RECENT)	{#if ENABLE_DEBUG	  svz_log (LOG_DEBUG, "nut: dropping too recent query\n");#endif	  ret = -1;	}    }  /* put the query extraction to the recent query hash */  else    {      t = time (NULL);      svz_hash_put (cfg->query, key, (void *) ((long) t));    }  svz_free (key);  return ret;}/* * Gnutella packet validation. This is absolutely necessary. It protects  * the local client as well as offer an additional line of defense against  * broadcasting spam to other connections. Return values: *  1 = packet ok *  0 = packet is dropped, but can be processed * -1 = invalid packet, do not process at all */intnut_validate_packet (svz_socket_t *sock, nut_header_t *hdr, 		     svz_uint8_t *packet){  nut_config_t *cfg = sock->cfg;  nut_client_t *client = sock->data;#if 0  fprintf (stdout, "validating packet 0x%02X (%s)\n", 	   hdr->function, nut_print_guid (hdr->id));#endif /* 1 */  /* Packet size validation */  switch (hdr->function)    {      /* Ping */    case NUT_PING_REQ:      if (hdr->length != 0)	{#if ENABLE_DEBUG	  svz_log (LOG_DEBUG, "nut: invalid ping payload\n");#endif	  return -1;	}      break;      /* Pong */    case NUT_PING_ACK:      if (hdr->length != SIZEOF_NUT_PONG)	{#if ENABLE_DEBUG	  svz_log (LOG_DEBUG, "nut: invalid pong payload\n");#endif	  return -1;	}      break;      /* Push Request */    case NUT_PUSH_REQ:      if (hdr->length != SIZEOF_NUT_PUSH)	{#if ENABLE_DEBUG	  svz_log (LOG_DEBUG, "nut: invalid push request payload\n");#endif	  return -1;	}      break;      /* Query */    case NUT_SEARCH_REQ:      if (hdr->length > 257)	{#if ENABLE_DEBUG	  svz_log (LOG_DEBUG, "nut: payload of query too big\n");#endif	  return -1;	}      if (nut_canonize_query (cfg, (char *) packet + SIZEOF_NUT_QUERY) == -1)	return -1;      break;      /* Query hits */    case NUT_SEARCH_ACK:      if (hdr->length > (SIZEOF_NUT_RECORD + 256) * 256)	{#if ENABLE_DEBUG	  svz_log (LOG_DEBUG, "nut: payload of query hits too big\n");#endif	  return -1;	}      break;      /* Invalid */    default:#if ENABLE_DEBUG      svz_log (LOG_DEBUG, "nut: invalid request 0x%02X\n", hdr->function);#endif      if (client->invalid++ > NUT_INVALID_PACKETS)	svz_sock_schedule_for_shutdown (sock);      return -1;    }  /* Hops and TTLs */  if (hdr->ttl <= 1)    {#if ENABLE_DEBUG      svz_log (LOG_DEBUG, "nut: packet died (zero TTL)\n", hdr->function);#endif      return 0;    }  hdr->hop++;  hdr->ttl--;  if (hdr->hop > cfg->max_ttl)    {#if ENABLE_DEBUG      svz_log (LOG_DEBUG, "nut: packet died (HOP > MaxTTL)\n",	       hdr->function); #endif      return 0;    }  if (hdr->ttl > 50)    {#if ENABLE_DEBUG      svz_log (LOG_DEBUG, "nut: packet dropped (TTL > 50)\n");#endif      return 0;    }  if (hdr->ttl > cfg->max_ttl)    {#if ENABLE_DEBUG      svz_log (LOG_DEBUG, "nut: decreasing packet TTL (%d -> %d)\n",	       hdr->ttl, cfg->max_ttl);#endif      hdr->ttl = (svz_uint8_t) cfg->max_ttl;    }  if (hdr->ttl + hdr->hop > cfg->max_ttl)    {#if ENABLE_DEBUG      svz_log (LOG_DEBUG, "nut: decreasing packet TTL (%d -> %d)\n",	       hdr->ttl, cfg->max_ttl - hdr->hop);#endif      hdr->ttl = (svz_uint8_t) (cfg->max_ttl - hdr->hop);    }  return 1;}/* * This is the routing routine for any incoming gnutella packet. * It return non-zero on routing errors and packet death. Otherwise * zero. */intnut_route (svz_socket_t *sock, nut_header_t *hdr, svz_uint8_t *packet){  nut_config_t *cfg = sock->cfg;  nut_packet_t *pkt;  svz_socket_t *xsock;  svz_socket_t **conn;  svz_uint8_t *header;  int n;  /* packet validation */  if ((n = nut_validate_packet (sock, hdr, packet)) == -1)    return -1;  else if (n == 0)    return 0;  /* route replies here */  if (hdr->function & 0x01)    {      /* is the GUID in the routing hash ? */      xsock = (svz_socket_t *) svz_hash_get (cfg->route, (char *) hdr->id);      if (xsock == NULL)	{	  pkt = (nut_packet_t *) svz_hash_get (cfg->packet, (char *) hdr->id);	  if (pkt == NULL)	    {	      svz_log (LOG_ERROR, "nut: error routing packet 0x%02X\n",		       hdr->function);	      cfg->errors++;	      return -1;	    }#if ENABLE_DEBUG	  svz_log (LOG_DEBUG, "nut: packet 0x%02X reply received\n",		   hdr->function);#endif	}      /* yes, send it to the connection the original query came from */      else	{	  /* try sending the header */	  header = nut_put_header (hdr);	  if (svz_sock_write (xsock, (char *) header, SIZEOF_NUT_HEADER) == -1)	    {	      svz_sock_schedule_for_shutdown (xsock);	      return 0;	    }	  /* send the packet body if necessary */	  if (hdr->length)	    {	      if (svz_sock_write (xsock, (char *) packet, hdr->length) == -1)		{		  svz_sock_schedule_for_shutdown (xsock);		  return 0;		}	    }	}    }  /*    * route queries here (hdr->function & 0x01 == 0x00), push request    * will be handle later.   */  else if (hdr->function != NUT_PUSH_REQ)    {      /* check if this query has been seen already */      xsock = (svz_socket_t *) svz_hash_get (cfg->route, (char *) hdr->id);      if (xsock != NULL)	{#if ENABLE_DEBUG	  svz_log (LOG_DEBUG, "nut: dropping duplicate packet 0x%02X\n",		   hdr->function);#endif	  return -1;	}      /* check if this query has been sent by ourselves */      pkt = (nut_packet_t *) svz_hash_get (cfg->packet, (char *) hdr->id);      if (pkt != NULL)	{#if ENABLE_DEBUG	  svz_log (LOG_DEBUG, "nut: dropping native packet 0x%02X\n",		   hdr->function);#endif	  return -1;	}      /* add the query to routing table */      svz_hash_put (cfg->route, (char *) hdr->id, sock);      /*        * Forward this query to all connections except the connection       * the server got it from.       */      if ((conn = (svz_socket_t **) svz_hash_values (cfg->conn)) != NULL)	{	  header = nut_put_header (hdr);	  for (n = 0; n < svz_hash_size (cfg->conn); n++)	    {	      xsock = conn[n];	      if (xsock == sock)		continue;	      if (svz_sock_write (xsock, (char *) header, 				  SIZEOF_NUT_HEADER) == -1)		{		  svz_sock_schedule_for_shutdown (xsock);		  svz_hash_xfree (conn);		  return 0;		}	      if (hdr->length)		{		  if (svz_sock_write (xsock, (char *) packet, 				      hdr->length) == -1)		    {		      svz_sock_schedule_for_shutdown (xsock);		      svz_hash_xfree (conn);		      return 0;		    }		}	    }	  svz_hash_xfree (conn);	}    }  return 0;}#else /* ENABLE_GNUTELLA */int nut_route_dummy; /* Shut compiler warnings up. */#endif /* not ENABLE_GNUTELLA */