src/ghortident.c

   1 #include <stdio.h>
   2 #include <unistd.h>
   3 #include <netinet/in.h>
   4 #include <string.h>
   5 #include <errno.h>
   6 #include <sys/types.h>
   7 #include <sys/socket.h>
   8
   9 #define DBG 0
  10
  11 int parseparams(int argc, char *argv[], ulong *adres, uint *rport, uint *lport, uint *service)
  12 {
  13         char *s;
  14         uint c, d;
  15
  16         if (argc<1) return 255;
  17
  18         *lport=80;
  19         *service=113;
  20
  21         switch (argc)
  22         {
  23                 case 2:
  24                         fprintf(stderr,"Error: missing remote port!\n");
  25                 case 1:
  26                         fprintf(stderr,"Usage: ident <xxx.xxx.xxx.xxx> <remote port> [local port] [ident port]\n");
  27                         return 1;
  28                 default:
  29                 case 5:
  30                         c=0;
  31                         s=argv[4];
  32                         while (*s)
  33                         {
  34                                 if (c<65536 && *s>='0' && *s<='9') c=c*10+*s-'0';
  35                                 else
  36                                 {
  37                                         fprintf(stderr,"Error: wrong ident port!\n");
  38                                         return 5;
  39                                 }
  40                                 s++;
  41                         }
  42                         *service=c;
  43                 case 4:
  44                         c=0;
  45                         s=argv[3];
  46                         while (*s)
  47                         {
  48                                 if (c<65536 && *s>='0' && *s<='9') c=c*10+*s-'0';
  49                                 else
  50                                 {
  51                                         fprintf(stderr,"Error: wrong local port!\n");
  52                                         return 4;
  53                                 }
  54                                 s++;
  55                         }
  56                         *lport=c;
  57                 case 3:
  58                         *adres=0;
  59                         c=d=0;
  60                         s=argv[1];
  61                         while (*s)
  62                         {
  63                                 if (*s>='0' && *s<='9')
  64                                 {
  65                                         c=c*10+*s-'0';
  66                                         if (c>255)
  67                                         {
  68                                                 fprintf(stderr,"Error: wrong address!\n");
  69                                                 return 2;
  70                                         }
  71                                 }
  72                                 else
  73                                         if (*s=='.')
  74                                         {
  75                                                 *adres=*adres*256+c;
  76                                                 c=0;
  77                                                 if (d++>=3)
  78                                                 {
  79                                                         fprintf(stderr,"Error: wrong address!\n");
  80                                                         return 2;
  81                                                 }
  82                                         }
  83                                         else
  84                                         {
  85                                                 fprintf(stderr,"Error: wrong address!\n");
  86                                                 return 2;
  87                                         }
  88                                 s++;
  89                         }
  90                         *adres=*adres*256+c;
  91
  92                         c=0;
  93                         s=argv[2];
  94                         while (*s)
  95                         {
  96                                 if (c<65536 && *s>='0' && *s<='9') c=c*10+*s-'0';
  97                                 else
  98                                 {
  99                                         fprintf(stderr,"Error: wrong remote port!\n");
 100                                         return 3;
 101                                 }
 102                                 s++;
 103                         }
 104                         *rport=c;
 105         }
 106         return 0;
 107 }
 108
 109 int main(int argc, char *argv[])
 110 {
 111         int sock;
 112         struct sockaddr_in addr;
 113         char buf[256];
 114         int count;
 115         ulong adres;
 116         uint rport, lport, service;
 117         int err;
 118         static const int val_one=1;
 119
 120         if (parseparams(argc,argv,&adres,&rport,&lport,&service)) return 3;
 121
 122         if (DBG) fprintf(stderr,"addr: %lX  rport: %u  lport: %u  service: %i\n",adres,rport,lport,service);
 123
 124         addr.sin_family=AF_INET;
 125         addr.sin_addr.s_addr=htonl(adres);
 126         addr.sin_port=htons(service);
 127
 128         sock=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
 129         setsockopt(sock,SOL_SOCKET,SO_KEEPALIVE,&val_one,sizeof(val_one));
 130
 131         if (DBG)
 132         {
 133                 err=errno;
 134                 fprintf(stderr,"socket: %i, errno: %i\n",sock,err);
 135         }
 136         if (sock==-1)
 137         {
 138                 fprintf(stderr,"Error: cannot create socket!\n");
 139                 return 4;
 140         }
 141
 142         count=connect(sock,(struct sockaddr*)&addr,sizeof(addr));
 143         if (DBG)
 144         {
 145                 err=errno;
 146                 fprintf(stderr,"connect: %i, errno: %i\n",count,err);
 147         }
 148
 149         if (count)
 150         {
 151                 fprintf(stderr,"Error: connection failed!\n");
 152                 return 5;
 153         }
 154
 155         count=snprintf(buf,sizeof(buf),"%d , %d\n",rport,lport);
 156         if (count==-1) return 1;
 157         if (write(sock,buf,count)!=count) return 2;
 158
 159         for (;;)
 160         {
 161                 count=read(sock,buf,sizeof(buf)-1);
 162                 if (count<=0) break;
 163                 buf[count]=0;
 164                 printf("%s",buf);
 165                 fflush(stdout);
 166         }
 167
 168         if (DBG) fprintf(stderr,"count = %d , errno = %d\n",count,errno);
 169         close(sock);
 170         return 0;
 171 }
 172