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old_proxy_server_with_cache.c
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527 lines (421 loc) · 17.2 KB
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#include "proxy_parse.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <fcntl.h>
#include <time.h>
#include <sys/wait.h>
#include <errno.h>
#include <pthread.h>
#include <semaphore.h>
#include <time.h>
#define MAX_CLIENTS 10
#define MAX_BYTES 4096
#define MAX_SIZE 200*(1<<20)
#define MAX_ELEMENT_SIZE 10*(1<<10)
typedef struct cache_element cache_element;
struct cache_element{
/* data */
char* data; //header data of the website
int len; //length of the PAYLOAD in bytes
char* url; //the url we need from the REQUEST
time_t lru_time_track; //time based LRU tracking (two methods - counter and time based)
cache_element* next; //to make a LINKED-LIST of the LRU cache
};
cache_element* find(char* url);
int add_cache_element(char* data, int size, char *url);
void remove_cache_element();
int port_number = 8080; //defining the port we at which the PROXY-SERVER will run
int proxy_socketId; //each client will have their own SOCKETS
pthread_t tid[MAX_CLIENTS]; //in total there are 10 MAX possible clients
sem_t semaphore;
pthread_mutex_t lock;
/*above MUTEX lock- now whenever we're using a SHARED RESOURCE such as the LRU cache in this case
we need to use the MUTEX lock in order to avoid the multi-JAMMING at that shared resource
LOCKS have only two values - 0 or 1
SEMAPHORES have more than 2 values
*/
cache_element* head;
int cache_size;
int connectRemoteServer(char* host_addr, int port_num) //the server other than the CACHE server (our MAIN server)
{
// Creating Socket for remote server ---------------------------
int remoteSocket = socket(AF_INET, SOCK_STREAM, 0);
if( remoteSocket < 0)
{
printf("error in Creating Socket.\n");
return -1;
}
// Get host by the name or ip address provided
struct hostent *host = gethostbyname(host_addr);
if(host == NULL)
{
fprintf(stderr, "no such host exists.\n");
return -1;
}
// inserts ip address and port number of host in struct `server_addr`
struct sockaddr_in server_addr;
bzero((char*)&server_addr, sizeof(server_addr));
server_addr.sin_family = AF_INET;
server_addr.sin_port = htons(port_num);
bcopy((char *)host->h_addr,(char *)&server_addr.sin_addr.s_addr,host->h_length);
// Connect to Remote server ----------------------------------------------------
if( connect(remoteSocket, (struct sockaddr*)&server_addr, (socklen_t)sizeof(server_addr)) < 0 )
{
fprintf(stderr, "Error in connecting !\n");
return -1;
}
// free(host_addr);
return remoteSocket;
}
int sendErrorMessage(int socket, int status_code) //sending error messages to the server, about the connection establishment
{
char str[1024];
char currentTime[50];
time_t now = time(0);
struct tm data = *gmtime(&now);
strftime(currentTime,sizeof(currentTime),"%a, %d %b %Y %H:%M:%S %Z", &data);
switch(status_code)
{ //the below messages are the STANDARD messages which are returned after several consequences of the request
case 400: snprintf(str, sizeof(str), "HTTP/1.1 400 Bad Request\r\nContent-Length: 95\r\nConnection: keep-alive\r\nContent-Type: text/html\r\nDate: %s\r\nServer: VaibhavN/14785\r\n\r\n<HTML><HEAD><TITLE>400 Bad Request</TITLE></HEAD>\n<BODY><H1>400 Bad Rqeuest</H1>\n</BODY></HTML>", currentTime);
printf("400 Bad Request\n");
send(socket, str, strlen(str), 0);
break;
case 403: snprintf(str, sizeof(str), "HTTP/1.1 403 Forbidden\r\nContent-Length: 112\r\nContent-Type: text/html\r\nConnection: keep-alive\r\nDate: %s\r\nServer: VaibhavN/14785\r\n\r\n<HTML><HEAD><TITLE>403 Forbidden</TITLE></HEAD>\n<BODY><H1>403 Forbidden</H1><br>Permission Denied\n</BODY></HTML>", currentTime);
printf("403 Forbidden\n");
send(socket, str, strlen(str), 0);
break;
case 404: snprintf(str, sizeof(str), "HTTP/1.1 404 Not Found\r\nContent-Length: 91\r\nContent-Type: text/html\r\nConnection: keep-alive\r\nDate: %s\r\nServer: VaibhavN/14785\r\n\r\n<HTML><HEAD><TITLE>404 Not Found</TITLE></HEAD>\n<BODY><H1>404 Not Found</H1>\n</BODY></HTML>", currentTime);
printf("404 Not Found\n");
send(socket, str, strlen(str), 0);
break;
case 500: snprintf(str, sizeof(str), "HTTP/1.1 500 Internal Server Error\r\nContent-Length: 115\r\nConnection: keep-alive\r\nContent-Type: text/html\r\nDate: %s\r\nServer: VaibhavN/14785\r\n\r\n<HTML><HEAD><TITLE>500 Internal Server Error</TITLE></HEAD>\n<BODY><H1>500 Internal Server Error</H1>\n</BODY></HTML>", currentTime);
//printf("500 Internal Server Error\n");
send(socket, str, strlen(str), 0);
break;
case 501: snprintf(str, sizeof(str), "HTTP/1.1 501 Not Implemented\r\nContent-Length: 103\r\nConnection: keep-alive\r\nContent-Type: text/html\r\nDate: %s\r\nServer: VaibhavN/14785\r\n\r\n<HTML><HEAD><TITLE>404 Not Implemented</TITLE></HEAD>\n<BODY><H1>501 Not Implemented</H1>\n</BODY></HTML>", currentTime);
printf("501 Not Implemented\n");
send(socket, str, strlen(str), 0);
break;
case 505: snprintf(str, sizeof(str), "HTTP/1.1 505 HTTP Version Not Supported\r\nContent-Length: 125\r\nConnection: keep-alive\r\nContent-Type: text/html\r\nDate: %s\r\nServer: VaibhavN/14785\r\n\r\n<HTML><HEAD><TITLE>505 HTTP Version Not Supported</TITLE></HEAD>\n<BODY><H1>505 HTTP Version Not Supported</H1>\n</BODY></HTML>", currentTime);
printf("505 HTTP Version Not Supported\n");
send(socket, str, strlen(str), 0);
break;
default: return -1;
}
return 1;
}
int handle_request(int clientSocketId, ParsedRequest *request, char *tempReq){
char *buf = (char *)malloc(sizeof(char)*MAX_BYTES);
strcpy(buf, "GET");
strcat(buf, request->path);
strcat(buf, " ");
strcat(buf, request->version);
strcat(buf, "\r\n");
size_t len = strlen(buf);
if(ParsedHeader_set(request, "Connection", "close") < 0){
printf("set header key is not working\n");
}
if(ParsedHeader_get(request, "Host") == NULL){
if(ParsedHeader_set(request, "Host", request->host) < 0){
printf("set host header key is not working\n");
}
}
if(ParsedRequest_unparse_headers(request, buf+len, (size_t)MAX_BYTES-len)<0){
printf("unparse failed!");
}
int server_port = 80; // Default Remote Server Port
if(request->port != NULL)
server_port = atoi(request->port);
int remoteSocketID = connectRemoteServer(request->host, server_port);
if(remoteSocketID < 0)
return -1;
int bytes_send = send(remoteSocketID, buf, strlen(buf), 0);
bzero(buf, MAX_BYTES);
bytes_send = recv(remoteSocketID, buf, MAX_BYTES-1, 0);
char *temp_buffer = (char*)malloc(sizeof(char)*MAX_BYTES); //temp buffer
int temp_buffer_size = MAX_BYTES;
int temp_buffer_index = 0;
while(bytes_send > 0)
{
bytes_send = send(clientSocketId, buf, bytes_send, 0);
for(int i=0;i<bytes_send/sizeof(char);i++){
temp_buffer[temp_buffer_index] = buf[i];
// printf("%c",buf[i]); // Response Printing
temp_buffer_index++;
}
temp_buffer_size += MAX_BYTES;
temp_buffer=(char*)realloc(temp_buffer,temp_buffer_size);
if(bytes_send < 0)
{
perror("Error in sending data to client socket.\n");
break;
}
bzero(buf, MAX_BYTES);
bytes_send = recv(remoteSocketID, buf, MAX_BYTES-1, 0);
}
temp_buffer[temp_buffer_index]='\0';
free(buf);
add_cache_element(temp_buffer, strlen(temp_buffer), tempReq);
printf("Done\n");
free(temp_buffer);
close(remoteSocketID);
return 0;
}
int checkHTTPversion(char *msg) //this method will return the HTTP version we'll need in order to return a character message
{
int version = -1;
if(strncmp(msg, "HTTP/1.1", 8) == 0)
{
version = 1;
}
else if(strncmp(msg, "HTTP/1.0", 8) == 0)
{
version = 1; // Handling this similar to version 1.1
}
else
version = -1;
return version;
}
int thread_fn(void *socketNew){
sem_wait(&semaphore);
int p;
sem_getvalue(&semaphore, p); //if semaphore value is -1 then its in USE, otherwise we can use it(for +ve values)
printf("semaphore value is %d\n", p);
int *t = (int*) socketNew;
int socket = *t; //gettinng the value from the POINTER
int bytes_send_client, len; //BYTES and LEN of it sent by CLIENT during a HTTP request
char *buffer = (char *)calloc(MAX_BYTES, sizeof(char));
bzero(buffer, MAX_BYTES);
bytes_send_client = recv(socket, buffer, MAX_BYTES, 0);
while (bytes_send_client > 0)
{
len = strlen(buffer);
if(strstr(buffer, "\r\n\r\n") == NULL){ //checking if the BUFFER contains some values or if its EOF
bytes_send_client = recv(socket, buffer + len, MAX_BYTES - len, 0); //receiving the available bytes on the socket
}else{ //otherwise break the LOOP
break;
}
}
//below creating a copy of BUFFER into a tempReq to search in the LRU cache
char *tempReq = (char*)malloc(strlen(buffer)*sizeof(char)+1);
for(int i = 0; i < strlen(buffer); i++){
tempReq[i] = buffer[i];
}
struct cache_element *temp = find(tempReq); //finding the 'tempReq' in the CACHE
if(temp != NULL){ //till the temp ptr is NULL
int size = temp->len/sizeof(char);
int pos = 0;
char response[MAX_BYTES];
while (pos < size) //this loop will send the requested URL to the socket
{
bzero(response, MAX_BYTES);
for(int i = 0; i < MAX_BYTES; i++){
response[i] = temp->data[i];
pos++;
}
send(socket, response, MAX_BYTES, 0); //this will send the response bytes to the SOCKET if any bytes exits/remaining
}
printf("data retrieved from cache\n");
printf("%s\n\n", response);
}else if(bytes_send_client > 0){ //if we've accepted the REQUEST from client then this is the case
len = strlen(buffer);
ParsedRequest *request = ParsedRequest_create();
if(ParsedRequest_parse(request, buffer, len) < 0){
printf("parsing failed\n");
}else{ //timestamp: 01:00:00
bzero(buffer, MAX_BYTES);
if(!strcmp(request->method, "GET")){
if(request->host && request->path && checkHTTPversion(request->version)==1){
bytes_send_client = handle_request(socket, request, tempReq);
if(bytes_send_client == -1){
sendErrorMessage(socket, 500);
}
}else{
sendErrorMessage(socket, 500);
}
}else{
printf("this code doesn't support any method apart from GET\n");
}
}
ParsedRequest_destroy(request);
}else if(bytes_send_client == 0){ //if the request is itself not coming from CLIENT then this is the condition we need to check
printf("client is disconnected");
}
shutdown(socket, SHUT_RDWR);
close(socket);
free(buffer);
sem_post(&semaphore);
sem_getvalue(&semaphore, p);
printf("semaphore post value is %d\n", p);
free(tempReq);
return(NULL);
}
int main(int argc, char* argv[]){
int client_socketId, client_len;
struct sockaddr_in server_addr, client_addr;
sem_init(&semaphore,0, MAX_CLIENTS);
pthread_mutex_init(&lock, NULL);
if(argv == 2){
port_number = atoi(argv[1]);
}
else{
printf("too few arguments\n");
exit(1);
}
printf("starting proxy server at port: %d\n", port_number);
proxy_socketId = socket(AF_INET, SOCK_STREAM, 0);
/*timestamp - 29:00*/
if(proxy_socketId < 0){
perror("failed to create a socket\n");
exit(1);
}
//the below code helps us to check for the ADDRESS already in use ERRORS-
int reuse = 1;
if(setsockopt(proxy_socketId, SOL_SOCKET, SO_REUSEADDR, (const char*)&reuse, sizeof(reuse)) < 0){
perror("setSockOpt failed\n");
}
bzero((char*)&server_addr, sizeof(server_addr));
server_addr.sin_family = AF_INET;
server_addr.sin_port = htons(port_number); //assigning PORT to the PROXY
server_addr.sin_addr.s_addr = INADDR_ANY; //allowing the server to accept connections from any network interface.
// Binding the socket
if( bind(proxy_socketId, (struct sockaddr*)&server_addr, sizeof(server_addr)) < 0 ) //assigning a name to a socket
{
perror("Port is not available\n");
exit(1);
}
printf("Binding on port: %d\n",port_number);
int listen_status = listen(proxy_socketId, MAX_CLIENTS);
if(listen_status < 0){
perror("error in listening\n");
exit(1);
}
int i = 0;
int Connected_socketId[MAX_CLIENTS];
// Infinite Loop for accepting connections
while(1)
{
bzero((char*)&client_addr, sizeof(client_addr)); // Clears struct client_addr
client_len = sizeof(client_addr);
// Accepting the connections
client_socketId = accept(proxy_socketId, (struct sockaddr*)&client_addr,(socklen_t*)&client_len); // Accepts connection
if(client_socketId < 0)
{
fprintf(stderr, "Error in Accepting connection !\n");
exit(1);
}
else{
Connected_socketId[i] = client_socketId; // Storing accepted client into array
}
// Getting IP address and port number of client
struct sockaddr_in* client_pt = (struct sockaddr_in*)&client_addr;
struct in_addr ip_addr = client_pt->sin_addr;
char str[INET_ADDRSTRLEN]; // INET_ADDRSTRLEN: Default ip address size
inet_ntop( AF_INET, &ip_addr, str, INET_ADDRSTRLEN );
printf("Client is connected with port number: %d and ip address: %s \n",ntohs(client_addr.sin_port), str);
//printf("Socket values of index %d in main function is %d\n",i, client_socketId);
pthread_create(&tid[i],NULL,thread_fn, (void*)&Connected_socketId[i]); // Creating a thread for each client accepted
i++;
}
close(proxy_socketId); // Close socket
return 0;
/*timestamp - 45:00*/
}
cache_element* find(char* url){
cache_element *site = NULL;
int temp_lock_val = pthread_mutex_lock(&lock);
printf("cache lock acquired: %d\n", temp_lock_val);
if(head != NULL){
site = head;
while(site!=NULL){
if(!strcmp(site->url, url)){
printf("LRU time track before: %ld", site->lru_time_track);
printf("url not found\n");
site->lru_time_track = time(NULL);
printf("LRU time track after %ld\n", site->lru_time_track);
break;
}
site = site->next;
}
}else{
printf("url not found\n");
}
temp_lock_val = pthread_mutex_unlock(&lock);
printf("lock is unlocked\n");
return site;
}
//for removing the element from the CACHE
void remove_cache_element(){
cache_element *p;
cache_element *q;
cache_element *temp;
int temp_lock_val = pthread_mutex_lock(&lock);
printf("lock is acquired\n");
if(head != NULL){
for(q = head, p = head, temp = head; q->next != NULL; q = q->next){
if(((q->next)->lru_time_track) < temp->lru_time_track){
temp = q->next;
p = q;
}
}
if(temp == head){
}else{
p->next = temp->next;
}
//if CACHE is not empty, then it should search for the node which has the least lru_time_track and will delete it
free(temp->data);
free(temp->url);
free(temp);
}
temp_lock_val = pthread_mutex_unlock(&lock);
printf("removed CACHE lock\n");
}
//adding the new element to the LRU cache, this function will be used
int add_cache_element(char* data, int size, char* url){
// Adds element to the cache
// sem_wait(&cache_lock);
int temp_lock_val = pthread_mutex_lock(&lock);
printf("Add Cache Lock Acquired %d\n", temp_lock_val);
int element_size=size+1+strlen(url)+sizeof(cache_element); // Size of the new element which will be added to the cache
if(element_size>MAX_ELEMENT_SIZE){
//sem_post(&cache_lock);
// If element size is greater than MAX_ELEMENT_SIZE we don't add the element to the cache
temp_lock_val = pthread_mutex_unlock(&lock);
printf("Add Cache Lock Unlocked %d\n", temp_lock_val);
// free(data);
// printf("--\n");
// free(url);
return 0;
}
else
{ while(cache_size+element_size>MAX_SIZE){
// We keep removing elements from cache until we get enough space to add the element
remove_cache_element();
}
cache_element* element = (cache_element*) malloc(sizeof(cache_element)); // Allocating memory for the new cache element
element->data= (char*)malloc(size+1); // Allocating memory for the response to be stored in the cache element
strcpy(element->data,data);
element -> url = (char*)malloc(1+( strlen( url )*sizeof(char) )); // Allocating memory for the request to be stored in the cache element (as a key)
strcpy( element -> url, url );
element->lru_time_track=time(NULL); // Updating the time_track
element->next=head;
element->len=size;
head=element;
cache_size+=element_size;
temp_lock_val = pthread_mutex_unlock(&lock);
printf("Add Cache Lock Unlocked %d\n", temp_lock_val);
//sem_post(&cache_lock);
// free(data);
// printf("--\n");
// free(url);
return 1;
}
return 0;
}