Segmentation fault in proxy server program - c

Question

I am trying to create a simple proxy server in c. I have used this url parser to parse the http request from the client. It returns a pointer to this structure:
struct parsed_url {
char *scheme; /* mandatory */
char *host; /* mandatory */
char *port; /* optional */
char *path; /* optional */
char *query; /* optional */
char *fragment; /* optional */
char *username; /* optional */
char *password; /* optional */
};
When I print the host name after parsing a http request from a client, it displays correct result like "www.google.com". But when I pass this hostname to gethostbyname(), it gives me segmentation fault. I am not bale to figure out why this happens.
Here is my code:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include "url_parser.h"
int main(int argc,char *argv[])
{
struct sockaddr_in server,client;
struct hostent *host;
int s1,s2,s3,len;
int port;
char ip[100];
char path[100];
int p;
struct parsed_url *url = NULL;
int n;
char buffer[500];
char site[500];
port = atoi(argv[1]);
bzero((char *)&server,sizeof(server));
server.sin_port = htons(port);
server.sin_addr.s_addr = INADDR_ANY;
server.sin_family = AF_INET;
s1 = socket(AF_INET,SOCK_STREAM,0);
if(bind(s1,(struct sockaddr *)&server,sizeof(server)) == -1) {
perror("can't bind");
exit(1);
}
if(listen(s1,10) == -1) {
perror("coudnt't listen");
exit(1);
}
len = sizeof(client);
s2 = accept(s1,(struct sockaddr *)&client,&len);
if(s2 == -1) {
perror("coudnt aceept");
exit(1);
}
memset(buffer,0,sizeof(buffer));
n = recv(s2,buffer,500,0);
if(n < 0) {
perror("not recieved");
exit(1);
}
buffer[n] = '\0';
url = parse_url(buffer);
bzero((char *)&client,sizeof(client));
client.sin_port = htons(80);
printf("%s %d",url->host,strlen(url->host));
host = gethostbyname((char *)url->host);
if(!host) {
herror("host error");
}
bcopy((char *)host->h_addr,(char *)&client.sin_addr.s_addr,host->h_length);
client.sin_family = AF_INET;
s3 = socket(AF_INET,SOCK_STREAM,0);
if(connect(s3,(struct sockaddr *)&client,sizeof(client)) == -1) {
perror("can't connect\n");
exit(1);
}
sprintf(site,"GET http://%s/ HTTP/1.0\n\n",url->host);
n = send(s3,site,strlen(site),0);
if(n < 0) {
perror("message not sent");
exit(1);
}
while(1) {
memset(site,0,sizeof(site));
n = recv(s3,site,500,0);
if(n < 0) {
perror("coudnot read");
exit(1);
}
//site[n] = '\0';
send(s2,site,strlen(site),0);
}
close(s1);
close(s2);
return 0;
}
The url_parser uses this to parse.