ip2name_dns.c

   1 /*
   2  * SARG Squid Analysis Report Generator      http://sarg.sourceforge.net
   3  *                                                            1998, 2012
   4  *
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   9  * ---------------------------------------------------------------------
  10  *
  11  *  This program is free software; you can redistribute it and/or modify
  12  *  it under the terms of the GNU General Public License as published by
  13  *  the Free Software Foundation; either version 2 of the License, or
  14  *  (at your option) any later version.
  15  *
  16  *  This program is distributed in the hope that it will be useful,
  17  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  *  GNU General Public License for more details.
  20  *
  21  *  You should have received a copy of the GNU General Public License
  22  *  along with this program; if not, write to the Free Software
  23  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
  24  *
  25  */
  26
  27 #include "include/conf.h"
  28 #include "include/defs.h"
  29 #include "include/ip2name.h"
  30 #ifdef HAVE_WS2TCPIP_H
  31 #include <ws2tcpip.h> //define getnameinfo on windows
  32 #endif
  33
  34 static enum ip2name_retcode ip2name_dns(char *ip,int ip_len);
  35
  36 //! The functions to resolve an IP address through tne dns.
  37 struct Ip2NameProcess Ip2NameDns=
  38 {
  39         "dns",
  40         NULL,//no next item yet
  41         NULL,//no configuration
  42         ip2name_dns
  43 };
  44
  45 /*!
  46 Resolve the IP address using a reverse DNS entry.
  47
  48 \param ip The IP address. It is replaced by the corresponding name if one
  49 can be found.
  50 \param ip_len The length of the \c ip buffer.
  51
  52 \return One of the ::ip2name_retcode value.
  53 */
  54 static enum ip2name_retcode ip2name_dns(char *ip,int ip_len)
  55 {
  56 #ifdef HAVE_GETNAMEINFO
  57         struct sockaddr_storage sa;
  58         int sockaddr_size;
  59         char host[NI_MAXHOST];
  60         int n1,n2,n3,n4,next=0;
  61         int error;
  62
  63         memset(&sa,0,sizeof(sa));
  64         if (sscanf(ip,"%d.%d.%d.%d%n",&n1,&n2,&n3,&n4,&next)==4 && ip[next]=='\0') {
  65                 struct sockaddr_in *s4=(struct sockaddr_in *)&sa;
  66                 if (inet_pton(AF_INET,ip,&s4->sin_addr)!=1) return(INRC_Error);
  67                 sa.ss_family=AF_INET;
  68                 sockaddr_size=sizeof(*s4);
  69         } else {
  70                 struct sockaddr_in6 *s6=(struct sockaddr_in6 *)&sa;
  71                 if (inet_pton(AF_INET6,ip,&s6->sin6_addr)!=1) return(INRC_Error);
  72                 sa.ss_family=AF_INET6;
  73                 sockaddr_size=sizeof(*s6);
  74         }
  75 #ifdef HAVE_SOCKADDR_SA_LEN
  76         sa.ss_len=sockaddr_size;
  77 #endif
  78         error=getnameinfo((struct sockaddr *)&sa,sockaddr_size,host,sizeof(host),NULL,0,NI_NAMEREQD);
  79         if (error==EAI_AGAIN) {
  80                 /*
  81                 This is a temporary failure. According to the man page we should try again but
  82                 it doesn't say if the program should wait before trying again nor how many attempts
  83                 before it becomes a fatal error. I could find no clues on internet so I try once and
  84                 leave it at that. Considering the number of IP addresses to resolve and the absence
  85                 of serious consequences should some IP fail to be resolved properly, it is best
  86                 not waste too much time on this.
  87                 */
  88                 error=getnameinfo((struct sockaddr *)&sa,sizeof(sa),host,sizeof(host),NULL,0,NI_NAMEREQD);
  89         }
  90         if (error==EAI_NONAME)
  91                 return(INRC_NotFound);
  92         if (error!=0) {
  93                 debuga(_("IP to name resolution (getnameinfo) on IP address \"%s\" failed with error %d - %s\n"),ip,error,gai_strerror(error));
  94                 return(INRC_Error);
  95         }
  96         safe_strcpy(ip,host,ip_len);
  97 #else //HAVE_GETNAMEINFO
  98         struct in_addr addr;
  99         struct hostent *hp;
 100         char **p;
 101 #ifdef __linux
 102         extern int h_errno;
 103 #endif
 104
 105 #ifdef HAVE_INET_ATON
 106         if (inet_aton(ip,&addr) == 0)
 107                 return(INRC_Error);
 108 #else
 109         addr.s_addr=inet_addr(ip);
 110         if (addr.s_addr==-1) return(INRC_Error);
 111 #endif
 112
 113         hp = gethostbyaddr((void *)&addr, sizeof (addr), AF_INET);
 114         if (hp == NULL) {
 115                 if (h_errno==HOST_NOT_FOUND)
 116                         return(INRC_NotFound);
 117                 return(INRC_Error);
 118         }
 119
 120         for (p = hp->h_addr_list; *p != 0; p++) {
 121                 struct in_addr in;
 122
 123                 (void) memcpy(&in.s_addr, *p, sizeof (in.s_addr));
 124                 safe_strcpy(ip,hp->h_name,ip_len);
 125         }
 126 #endif
 127         return(INRC_Found);
 128 }
 129