proxy/vproxy.c

   1
   2 #include <stdio.h>
   3 #include <signal.h>
   4 #include <string.h>
   5 #include <stdlib.h>
   6 #include <netdb.h>
   7 #include <sys/types.h>
   8 #include <sys/socket.h>
   9 #include <netinet/in.h>
  10 #include <arpa/inet.h>
  11 #include <errno.h>
  12 #include <fcntl.h>
  13 #include <unistd.h>
  14 #include <sys/param.h>
  15
  16 /* Generic Proxy 1.1 */
  17
  18 static void sig_usr(int);
  19
  20 void Usage(void);
  21
  22 #define BUFSIZE 1024
  23
  24 int main(int argc,char *argv[])
  25 {
  26     char c;
  27
  28     struct hostent *hostptr;
  29     struct hostent *l_hostptr;
  30     int rnewsockfd;
  31     char rhost[100] = "127.0.0.1";
  32     char lhost[100] = "0.0.0.0";
  33     int rport = 9080;
  34     int lport = 9081;
  35
  36     int len;
  37     char buffer[BUFSIZE];
  38
  39     char logfile[MAXPATHLEN] = "";
  40     char filename[MAXPATHLEN];
  41     int status;
  42     int inf;
  43     int outf;
  44     int to_log=0;
  45     int in_bgr=1;
  46
  47     int rpid,lpid;
  48     int sockfd, lnewsockfd, clilen;
  49     struct sockaddr_in cli_addr, serv_addr;
  50
  51
  52
  53     while( (c = getopt(argc, argv, "A:a:S:s:R:r:L:l:D:d:Ffh")) != EOF ) {
  54         switch( toupper(c) ) {
  55         case 'S':
  56             strcpy(rhost, optarg);
  57             break;
  58         case 'A':
  59             strcpy(lhost, optarg);
  60             break;
  61         case 'R':
  62             rport = atoi(optarg);
  63             break;
  64         case 'L':
  65             lport = atoi(optarg);
  66             break;
  67         case 'D':
  68             to_log = 1;
  69             strcpy(logfile, optarg);
  70             break;
  71         case 'F':
  72             in_bgr = 0;
  73             break;
  74         default:
  75             Usage();
  76             return -1;
  77         }
  78     }
  79
  80     if( strcmp(rhost, "") == 0 ) {
  81         Usage();
  82         return(-1);
  83     }
  84
  85     printf("Starting proxy from %s:%d to remote %s:%d\n", lhost, lport, rhost,
  86            rport);
  87
  88     hostptr = gethostbyname(rhost);
  89     if( hostptr == NULL )
  90     {
  91       fprintf( stderr, "failed to resolve remote ip address: %s (h_errno=%d)\n",
  92                rhost, h_errno );
  93       exit(2);
  94     }
  95     l_hostptr = gethostbyname(lhost);
  96     if( l_hostptr == NULL )
  97     {
  98       fprintf( stderr, "failed to resolve local ip address: %s (h_errno=%d)\n",
  99                lhost, h_errno );
 100       exit(2);
 101     }
 102
 103     /*
 104     ** Opening a socket
 105     */
 106     sockfd = socket(AF_INET, SOCK_STREAM, 0);
 107     serv_addr.sin_family = AF_INET;
 108     (void) memcpy(&serv_addr.sin_addr.s_addr, *(l_hostptr->h_addr_list),
 109                       sizeof(serv_addr.sin_addr.s_addr)) ;
 110     serv_addr.sin_port = htons(lport);
 111     status = 1;
 112     setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, (char *)&status, sizeof(int));
 113     if( bind(sockfd, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) < 0) {
 114         perror("failed binding server socket");
 115         exit(1);
 116     }
 117
 118     /*
 119     ** Start running in background by default
 120     */
 121     if( in_bgr && fork() ) {
 122         exit(0);
 123     }
 124
 125     /*
 126     ** Set queue length and signal interrupt
 127     */
 128     listen(sockfd,5);
 129     signal(SIGCHLD,sig_usr);
 130
 131     for ( ; ; ) {
 132
 133         /*
 134         ** Wait for new clients
 135         */
 136         clilen = sizeof(cli_addr);
 137         lnewsockfd = -1;
 138         while( lnewsockfd < 0 ) {
 139             lnewsockfd = accept(sockfd, (struct sockaddr *)&cli_addr, &clilen);
 140             if( lnewsockfd > 0 )
 141                 break;
 142
 143             /*
 144             ** It might happen that we got a signal and exited accept
 145             ** In this case restart accept and continue to wait
 146             */
 147             if( (lnewsockfd == -1) && (errno == EINTR) )
 148                 continue;
 149
 150             /*
 151             ** Otherwise, we've just failed, exit
 152             */
 153             perror("failed in accept");
 154             exit(0);
 155         }
 156
 157         printf( "Connecting client from %s to %s:%d\n",
 158                 inet_ntoa(cli_addr.sin_addr), rhost, rport);
 159
 160         /*
 161         ** Pass the new connection throught to the server
 162         */
 163         rnewsockfd = socket(AF_INET, SOCK_STREAM, 0);
 164         serv_addr.sin_family = AF_INET;
 165         (void) memcpy(&serv_addr.sin_addr.s_addr, *(hostptr->h_addr_list),
 166                       sizeof(serv_addr.sin_addr.s_addr)) ;
 167         serv_addr.sin_port = htons(rport);
 168         connect(rnewsockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr));
 169
 170         /*
 171         ** Forking the baby-sitter
 172         */
 173         if (fork() == 0) {
 174             /*
 175             ** Starting first child. It will read from client and sent to
 176             ** remote server
 177             */
 178             if ((lpid = fork()) == 0) {
 179                 if( strcmp(logfile, "") != 0 ) {
 180                     sprintf(filename, "%s.%d.out", logfile, getpid());
 181                     outf = open(filename, O_RDWR|O_TRUNC|O_CREAT, 0666);
 182                 }
 183                 while( (len = read(lnewsockfd, buffer, BUFSIZE)) > 0 ) {
 184                     if( len ) {
 185                         if( outf > 0 )
 186                             write(outf, buffer, len);
 187                         write(rnewsockfd, buffer, len);
 188                     }
 189                 }
 190
 191                 /*
 192                 ** When finished reading, exit
 193                 */
 194                 close(lnewsockfd);
 195                 close(rnewsockfd);
 196                 close(outf);
 197                 exit(0);
 198             } else if (lpid < 0) {
 199                 /*
 200                 ** Fork failed
 201                 */
 202                 perror("failed forking 1st child");
 203                 exit(1);
 204             }
 205
 206             /*
 207             ** Start second child. It will read from the server and write
 208             ** to our client
 209             */
 210             if ((rpid = fork()) == 0  ) {
 211                 if( strcmp(logfile, "") != 0 ) {
 212                     sprintf(filename, "%s.%d.in", logfile, getpid());
 213                     inf = open(filename, O_RDWR|O_TRUNC|O_CREAT, 0666);
 214                 }
 215                 while( (len = read(rnewsockfd, buffer, BUFSIZE)) > 0) {
 216                     if( len ) {
 217                         if( inf > 0 )
 218                             write(inf, buffer, len);
 219                         write(lnewsockfd, buffer, len);
 220                     }
 221                 }
 222
 223                 /*
 224                 ** When finished writing, exist
 225                 */
 226                 close(lnewsockfd);
 227                 close(rnewsockfd);
 228                 close(inf);
 229                 exit(0);
 230             }
 231             else if (rpid < 0) {
 232                 /*
 233                 ** Fork failed
 234                 */
 235                 perror("failed forking 2nd child");
 236                 exit(1);
 237             }
 238
 239             /*
 240             ** Now baby-sitter waits for any child to finish
 241             */
 242             close(lnewsockfd);
 243             close(rnewsockfd);
 244             wait(&status);
 245
 246             /*
 247             ** If any of the children terminated, kill all of them
 248             */
 249             kill(rpid,SIGKILL);
 250             kill(lpid,SIGKILL);
 251             exit(0);
 252         } /* baby-sitter */
 253
 254         /*
 255         ** The main process closes files and goes on to wait for new clients
 256         */
 257         close(lnewsockfd);
 258         close(rnewsockfd);
 259     } /*  forever */
 260
 261 } /* main */
 262
 263 void Usage()
 264 {
 265     printf("Usage: vproxy [-a local_ip=0.0.0.0] [-l local_port=9081] [-s remote_ip=127.0.0.1] [-r remote_port=9080] [-d log_prefix]\n");
 266
 267 }
 268
 269 static void sig_usr(int signo)
 270 {
 271
 272     int status,pid;
 273
 274     pid = wait(&status);
 275     signal(SIGCHLD,sig_usr);
 276
 277 }
 278