在Ubuntu上使用C++進行網絡編程，你可以使用套接字（socket）API。以下是一個簡單的例子，展示了如何創建一個TCP服務器和客戶端。
首先，確保你已經安裝了g++編譯器和libssl-dev庫（用于SSL/TLS支持，可選）。
sudo apt update
sudo apt install g++ libssl-dev
創建一個名為tcp_server.cpp的文件，并添加以下代碼：
#include <iostream>
#include <cstring>
#include <sys/socket.h>
#include <netinet/in.h>
#include <unistd.h>
int main() {
int server_fd, new_socket;
struct sockaddr_in address;
int opt = 1;
int addrlen = sizeof(address);
char buffer[1024] = {0};
const char* hello = "Hello from server";
// Creating socket file descriptor
if ((server_fd = socket(AF_INET, SOCK_STREAM, 0)) == 0) {
perror("socket failed");
exit(EXIT_FAILURE);
}
// Forcefully attaching socket to the port 8080
if (setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR | SO_REUSEPORT, &opt, sizeof(opt))) {
perror("setsockopt");
exit(EXIT_FAILURE);
}
address.sin_family = AF_INET;
address.sin_addr.s_addr = INADDR_ANY;
address.sin_port = htons(8080);
// Bind the socket to the address
if (bind(server_fd, (struct sockaddr*)&address, sizeof(address)) < 0) {
perror("bind failed");
exit(EXIT_FAILURE);
}
// Listen for connections
if (listen(server_fd, 3) < 0) {
perror("listen");
exit(EXIT_FAILURE);
}
// Accept a connection
if ((new_socket = accept(server_fd, (struct sockaddr*)&address, (socklen_t*)&addrlen)) < 0) {
perror("accept");
exit(EXIT_FAILURE);
}
// Read data from the client
read(new_socket, buffer, 1024);
std::cout << "Message from client: " << buffer << std::endl;
// Send a response back to the client
send(new_socket, hello, strlen(hello), 0);
std::cout << "Hello message sent" << std::endl;
// Close the socket
close(new_socket);
close(server_fd);
return 0;
}
創建一個名為tcp_client.cpp的文件，并添加以下代碼：
#include <iostream>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <string.h>
int main() {
int sock = 0;
struct sockaddr_in serv_addr;
const char* hello = "Hello from client";
char buffer[1024] = {0};
// Create a socket
if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
std::cout << "
Socket creation error
";
return -1;
}
serv_addr.sin_family = AF_INET;
serv_addr.sin_port = htons(8080);
// Convert IPv4 and IPv6 addresses from text to binary form
if(inet_pton(AF_INET, "127.0.0.1", &serv_addr.sin_addr) <= 0) {
std::cout << "
Invalid address/ Address not supported
";
return -1;
}
// Connect to the server
if (connect(sock, (struct sockaddr*)&serv_addr, sizeof(serv_addr)) < 0) {
std::cout << "
Connection Failed
";
return -1;
}
// Send a message to the server
send(sock, hello, strlen(hello), 0);
std::cout << "Hello message sent" << std::endl;
// Read the response from the server
read(sock, buffer, 1024);
std::cout << "Message from server: " << buffer << std::endl;
// Close the socket
close(sock);
return 0;
}
編譯服務器和客戶端：
g++ -o tcp_server tcp_server.cpp
g++ -o tcp_client tcp_client.cpp
運行服務器：
./tcp_server
在另一個終端運行客戶端：
./tcp_client
你應該會看到服務器和客戶端之間的通信。
如果你需要使用SSL/TLS進行加密通信，可以使用OpenSSL庫。首先安裝OpenSSL開發庫：
sudo apt install libssl-dev
然后修改服務器和客戶端的代碼以使用SSL/TLS。
#include <iostream>
#include <cstring>
#include <sys/socket.h>
#include <netinet/in.h>
#include <unistd.h>
#include <openssl/ssl.h>
#include <openssl/err.h>
void init_openssl() {
SSL_load_error_strings();
OpenSSL_add_ssl_algorithms();
}
void cleanup_openssl() {
EVP_cleanup();
}
SSL_CTX* create_context() {
const SSL_METHOD* method;
SSL_CTX* ctx;
method = TLS_server_method();
ctx = SSL_CTX_new(method);
if (!ctx) {
perror("Unable to create SSL context");
ERR_print_errors_fp(stderr);
exit(EXIT_FAILURE);
}
return ctx;
}
void configure_context(SSL_CTX* ctx) {
SSL_CTX_set_ecdh_auto(ctx, 1);
// Set the key and cert
if (SSL_CTX_use_certificate_file(ctx, "server.crt", SSL_FILETYPE_PEM) <= 0) {
ERR_print_errors_fp(stderr);
exit(EXIT_FAILURE);
}
if (SSL_CTX_use_PrivateKey_file(ctx, "server.key", SSL_FILETYPE_PEM) <= 0 ) {
ERR_print_errors_fp(stderr);
exit(EXIT_FAILURE);
}
}
int main() {
int server_fd, new_socket;
struct sockaddr_in address;
int opt = 1;
int addrlen = sizeof(address);
char buffer[1024] = {0};
const char* hello = "Hello from server";
init_openssl();
SSL_CTX* ctx = create_context();
configure_context(ctx);
if ((server_fd = socket(AF_INET, SOCK_STREAM, 0)) == 0) {
perror("socket failed");
exit(EXIT_FAILURE);
}
if (setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR | SO_REUSEPORT, &opt, sizeof(opt))) {
perror("setsockopt");
exit(EXIT_FAILURE);
}
address.sin_family = AF_INET;
address.sin_addr.s_addr = INADDR_ANY;
address.sin_port = htons(8080);
if (bind(server_fd, (struct sockaddr*)&address, sizeof(address)) < 0) {
perror("bind failed");
exit(EXIT_FAILURE);
}
if (listen(server_fd, 3) < 0) {
perror("listen");
exit(EXIT_FAILURE);
}
if ((new_socket = accept(server_fd, (struct sockaddr*)&address, (socklen_t*)&addrlen)) < 0) {
perror("accept");
exit(EXIT_FAILURE);
}
SSL* ssl;
SSL_set_fd(ssl, new_socket);
if (SSL_accept(ssl) <= 0) {
ERR_print_errors_fp(stderr);
} else {
SSL_write(ssl, hello, strlen(hello));
std::cout << "Hello message sent" << std::endl;
}
SSL_shutdown(ssl);
SSL_free(ssl);
close(new_socket);
close(server_fd);
SSL_CTX_free(ctx);
cleanup_openssl();
return 0;
}
#include <iostream>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <openssl/ssl.h>
#include <openssl/err.h>
void init_openssl() {
SSL_load_error_strings();
OpenSSL_add_ssl_algorithms();
}
void cleanup_openssl() {
EVP_cleanup();
}
SSL_CTX* create_context() {
const SSL_METHOD* method;
SSL_CTX* ctx;
method = TLS_client_method();
ctx = SSL_CTX_new(method);
if (!ctx) {
perror("Unable to create SSL context");
ERR_print_errors_fp(stderr);
exit(EXIT_FAILURE);
}
return ctx;
}
void configure_context(SSL_CTX* ctx) {
SSL_CTX_set_default_verify_paths(ctx);
}
int main() {
int sock = 0;
struct sockaddr_in serv_addr;
const char* hello = "Hello from client";
char buffer[1024] = {0};
init_openssl();
SSL_CTX* ctx = create_context();
configure_context(ctx);
if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
std::cout << "
Socket creation error
";
return -1;
}
serv_addr.sin_family = AF_INET;
serv_addr.sin_port = htons(8080);
if(inet_pton(AF_INET, "127.0.0.1", &serv_addr.sin_addr) <= 0) {
std::cout << "
Invalid address/ Address not supported
";
return -1;
}
if (connect(sock, (struct sockaddr*)&serv_addr, sizeof(serv_addr)) < 0) {
std::cout << "
Connection Failed
";
return -1;
}
SSL* ssl;
ssl = SSL_new(ctx);
SSL_set_fd(ssl, sock);
if (SSL_connect(ssl) <= 0) {
ERR_print_errors_fp(stderr);
} else {
SSL_write(ssl, hello, strlen(hello));
std::cout << "Hello message sent" << std::endl;
}
SSL_shutdown(ssl);
SSL_free(ssl);
close(sock);
SSL_CTX_free(ctx);
cleanup_openssl();
return 0;
}
你可以使用OpenSSL生成自簽名證書和密鑰：
openssl req -x509 -newkey rsa:4096 -keyout server.key -out server.crt -days 365 -nodes
按照提示輸入相關信息。
編譯服務器和客戶端：
g++ -o tcp_server ssl_server.cpp -lssl -lcrypto
g++ -o tcp_client ssl_client.cpp -lssl -lcrypto
運行服務器：
./tcp_server
在另一個終端運行客戶端：
./tcp_client
你應該會看到服務器和客戶端之間的加密通信。
通過這些步驟，你可以在Ubuntu上使用C++進行基本的網絡編程，并且可以選擇性地使用SSL/TLS進行加密通信。
