PROJECT 5
Client code :
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <arpa/inet.h>
#include <unistd.h>
#define SERVER_IP "127.0.0.1"
#define SERVER_PORT 8080
#define BUFFER_SIZE 1024
int main() {
int clientSocket;
struct sockaddr_in serverAddr;
char buffer[BUFFER_SIZE];
clientSocket = socket(AF_INET, SOCK_STREAM, 0);
if (clientSocket == -1) {
perror("Socket creation failed");
return EXIT_FAILURE;
}
serverAddr.sin_family = AF_INET;
serverAddr.sin_port = htons(SERVER_PORT);
inet_pton(AF_INET, SERVER_IP, &serverAddr.sin_addr);
if (connect(clientSocket, (struct sockaddr *)&serverAddr,
sizeof(serverAddr)) < 0) {
perror("Connection failed");
return EXIT_FAILURE;
}
// Sample file metadata (filename, hash, and client port)
char filename[] = "example.txt";
char fullFileHash[] =
"abcdef1234567890abcdef1234567890abcdef1234567890abcdef1234567890";
int clientPort = 5001;
// Creating JSON string manually
snprintf(buffer, BUFFER_SIZE,
"{\"filename\":\"%s\",\"fullFileHash\":\"%s\",\"clientPort\":%d}",
filename, fullFileHash, clientPort);
// Send data
send(clientSocket, buffer, strlen(buffer), 0);
printf("File registration sent to server.\n");
close(clientSocket);
return 0;
}
Server Code :
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <arpa/inet.h>
#include <unistd.h>
#define PORT 8080
#define MAXPEERS 10
#define BUFFER_SIZE 1024
// Structure to store file info and clients
struct FileInfo {
char filename[100];
char fullFileHash[65]; // SHA-256 hash (64 hex chars + null
terminator)
char clientIP[MAXPEERS][INET_ADDRSTRLEN];
int clientPort[MAXPEERS];
int numberOfPeers;
struct FileInfo *next;
};
// Head of linked list
struct FileInfo *head = NULL;
// Function to find a file entry by hash
struct FileInfo* findFileByHash(const char *hash) {
struct FileInfo *current = head;
while (current != NULL) {
if (strcmp(current->fullFileHash, hash) == 0) return current;
current = current->next;
}
return NULL;
}
// Function to check if client is already registered
int isClientRegistered(struct FileInfo *file, const char *ip, int port) {
for (int i = 0; i < file->numberOfPeers; i++) {
if (strcmp(file->clientIP[i], ip) == 0 && file->clientPort[i] ==
port) {
return 1; // Already registered
}
}
return 0;
}
// Function to register file
void registerFile(const char *filename, const char *hash, const char *ip,
int port) {
struct FileInfo *file = findFileByHash(hash);
if (file != NULL) {
// File exists, add client if not already registered
if (!isClientRegistered(file, ip, port)) {
strcpy(file->clientIP[file->numberOfPeers], ip);
file->clientPort[file->numberOfPeers] = port;
file->numberOfPeers++;
}
} else {
// Create new file entry
struct FileInfo *newFile = (struct FileInfo
*)malloc(sizeof(struct FileInfo));
strcpy(newFile->filename, filename);
strcpy(newFile->fullFileHash, hash);
strcpy(newFile->clientIP[0], ip);
newFile->clientPort[0] = port;
newFile->numberOfPeers = 1;
newFile->next = head;
head = newFile;
}
}
// Function to display registered files
void displayFiles() {
struct FileInfo *current = head;
printf("\n=== Registered Files ===\n");
while (current != NULL) {
printf("File: %s\nHash: %s\nClients:\n", current->filename,
current->fullFileHash);
for (int i = 0; i < current->numberOfPeers; i++) {
printf(" - %s:%d\n", current->clientIP[i], current-
>clientPort[i]);
}
printf("-------------------------\n");
current = current->next;
}
}
// Function to handle client connections
void handleClient(int clientSocket, struct sockaddr_in clientAddr) {
char buffer[BUFFER_SIZE] = {0};
recv(clientSocket, buffer, BUFFER_SIZE, 0);
char filename[100], hash[65];
int clientPort;
// Basic parsing (not full JSON parsing)
sscanf(buffer, "{\"filename\":\"%[^\"]\",\"fullFileHash\":\"%
[^\"]\",\"clientPort\":%d}", filename, hash, &clientPort);
char clientIP[INET_ADDRSTRLEN];
inet_ntop(AF_INET, &clientAddr.sin_addr, clientIP, INET_ADDRSTRLEN);
registerFile(filename, hash, clientIP, clientPort);
displayFiles();
close(clientSocket);
}
// Main server function
int main() {
int serverSocket, clientSocket;
struct sockaddr_in serverAddr, clientAddr;
socklen_t addrSize = sizeof(clientAddr);
serverSocket = socket(AF_INET, SOCK_STREAM, 0);
if (serverSocket == -1) {
perror("Socket creation failed");
return EXIT_FAILURE;
}
serverAddr.sin_family = AF_INET;
serverAddr.sin_addr.s_addr = INADDR_ANY;
serverAddr.sin_port = htons(PORT);
if (bind(serverSocket, (struct sockaddr *)&serverAddr,
sizeof(serverAddr)) < 0) {
perror("Bind failed");
return EXIT_FAILURE;
}
if (listen(serverSocket, 10) < 0) {
perror("Listen failed");
return EXIT_FAILURE;
}
printf("Server is listening on port %d...\n", PORT);
while (1) {
clientSocket = accept(serverSocket, (struct sockaddr
*)&clientAddr, &addrSize);
if (clientSocket < 0) {
perror("Accept failed");
continue;
}
handleClient(clientSocket, clientAddr);
}
close(serverSocket);
return 0;
}
Output :
