c - unable to get my proxy server to send http requested information to client- Socket programming -

my objective of programs implement proxy server can connected single client , allow http request.

the requirements

1. to create c based client-server architecture using sockets
2. the proxy server should able accept , service single client's http requests

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code

client.c

    #include <stdio.h>     #include <sys/types.h>     #include <sys/socket.h>     #include <netinet/in.h>     #include <netdb.h>     #include <string.h>     #include <stdlib.h>       int main(int argc, char *argv[]){  int sockfd, portnum, n; struct sockaddr_in serv_addr; struct hostent *server;  char buffer[256]; if(argc < 3){   fprintf(stderr, "usage %s hostname port\n", argv[0]);   exit(1); } portnum = atoi(argv[2]); sockfd= socket(af_inet, sock_stream, 0);  if(sockfd <0){  perror("error opening socket");  exit(1); } server= gethostbyname(argv[1]); if(sockfd  == null){  fprintf(stderr,"error, no such host\n");  exit(1); } bzero((char *) &serv_addr, sizeof(serv_addr)); serv_addr.sin_family = af_inet; bcopy((char *)server->h_addr,      (char *)&serv_addr.sin_addr.s_addr,       server->h_length);  serv_addr.sin_port = htons(portnum);  if(connect(sockfd,(struct sockaddr *)&serv_addr,sizeof(serv_addr)) <0){  fprintf(stderr,"error, on connecting");  exit(1); } printf("please enter host name: "); bzero(buffer,256); fgets(buffer,255,stdin); n=write(sockfd,buffer,strlen(buffer)); if(n<0){  printf("error writing socket");  exit(1); }  bzero(buffer,256); n=read(sockfd,buffer,255); if(n<0){  printf("error reading socket");  exit(1); } printf("%s\n", buffer);       return 0;     } 

proxy server.c

    #include <stdio.h>     #include <sys/types.h>     #include <sys/socket.h>     #include <netinet/in.h>     #include <arpa/inet.h>     #include <unistd.h>     #include <sys/wait.h>     #include <stdlib.h>     #include <netdb.h>     #include <string.h>        int main(int argc, char *argv[]){  int sockfd, newsockfd, portnum, clilen; char buffer[256], hostname[256]; pid_t p_id; struct sockaddr_in serv_addr, cli_addr; int n, pid;  if(argc < 2){     fprintf(stderr, "error, no port provided!\n");     exit(1); } sockfd = socket(af_inet, sock_stream, 0);//socket made  if(sockfd < 0){     fprintf(stderr,"error opening socket!!");     exit(1); } bzero((char *) &serv_addr, sizeof(serv_addr)); portnum = atoi(argv[1]);//port num  serv_addr.sin_family = af_inet; serv_addr.sin_addr.s_addr = htonl(inaddr_any); serv_addr.sin_port = htons(portnum);   if(bind(sockfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr)) < 0){     fprintf(stderr,"error on binding");     exit(1); }  if( listen(sockfd, 5) < 0){  printf("error on listen");  exit(1); }      // accept         clilen = sizeof(cli_addr);     do{  newsockfd = accept(sockfd, (struct sockaddr *) &cli_addr, &clilen); if(newsockfd<0){     fprintf(stderr,"error on accept\n");     exit(1); }      pid=fork();     if(pid==0){  bzero(buffer, 256); n= read(newsockfd, buffer, 255);  if(n<0){//message client  fprintf(stderr,"error reading socket\n");  exit(1); }     strcpy(hostname, buffer); printf("here hostname : %s\n", hostname);  //variables used acsessing webserver? int sockwb, wbport, x; struct sockaddr_in webser_addr; struct hostent *wbhost; char webbuf[510];//sending webserver  wbport =80;//port used access web server       sockwb = socket(af_inet, sock_stream, 0);     if(sockwb <0){         printf("error opeing websocket\n");         exit(1);     }     wbhost= gethostbyname(hostname);     printf("%s", wbhost->h_name);     if(sockwb == -1){         printf("no such web host\n");         exit(1);     }     bzero((char*) &webser_addr, sizeof(webser_addr));     webser_addr.sin_family = af_inet;          bcopy((char *)wbhost->h_addr,                            (char *)&webser_addr.sin_addr.s_addr,                    wbhost->h_length);                    webser_addr.sin_port = htons(wbport);        if(connect(sockwb,(struct sockaddr *)&webser_addr,sizeof(webser_addr)) < 0){         printf("error on web connecting\n");         exit(1);     }     bzero(webbuf,510);     strcpy(webbuf, "get http://");     strcat(webbuf, hostname);     strcat(webbuf, " http/1.1");      printf("%s\n", webbuf);     x=write(sockwb,webbuf,strlen(webbuf));     if(x<0){         printf("error writing web sock");         exit(1);     }        bzero(webbuf,510);     x=read(sockwb,webbuf,510);     if(n<0){             printf("error reading web socket");         exit(1);     }     n = write(newsockfd, webbuf,255 );//write client  if (n<0){    fprintf(stderr,"error writing socket");    exit(1); }  printf("%s\n", webbuf); }//end of if pid==0  printf("closing client"); close(newsockfd);//closing client socket       }while(1);     return 0;     } 

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i have been able implement simple client-server exchange sockets, issue http request. have access web server through port 80 using method.

the way have input client sending proxy server should : www.name.com

the server doesn't seem doing after initial connection client.

as usual, null-terminated strings not managed here. when following construct used

send(sock, buff, strlen(buf)); 

the trailing null-terminated character not sent. on receiving side, there 2 problems. first, recv(sock, buff, sizeof(buff)); can receive unpredictable amount of bytes - 1 size of string provided. need read until read message. here comes dilemma - how know how long actual message? answer either agree on size of strings in advance, , send many bytes (regardless of actual string length) or prefix the string it's size in message. second problem if luck whole string read, not null-terminated, , such, unusable in program. has null-terminated manually.