linux网络编程示例

简单TCP、UDP编程示例。

TCP

• TCP客户端与服务器通信模型

• 服务器代码

#include <sys/socket.h> #include <netinet/in.h> #include <arpa/inet.h> #include <errno.h> #include <stdio.h> #include <unistd.h> #include <string.h>  int main(void) {     const char ip[] = "127.0.0.1";     const int port = 9006;      //创建socket，使用IP协议（PF_INET）+TCP协议（SOCK_STREAM）     int fd_listen = socket(PF_INET, SOCK_STREAM, 0);      //绑定固定ip:port地址     in_addr_t ip_num = inet_addr(ip);     sockaddr_in addr_server = {AF_INET, port, ip_num};     bind(fd_listen, (sockaddr *)&addr_server, sizeof(addr_server));      //监听socket     listen(fd_listen, 10);      //接受客户端连接，并返回连接socket     sockaddr_in addr_client;     socklen_t len_client_addr = sizeof(addr_client);     int fd_conn = accept(fd_listen, (sockaddr *)&addr_client, &len_client_addr);      //接收客户端数据     printf("start receiving data...n");      char buf[4096];     while (true)     {         memset(buf, '', sizeof(buf));         int ret = recv(fd_conn, buf, sizeof(buf) - 1, 0);          // recv返回0，表示客户端断开连接         if (ret == 0)         {             printf("connection closedn");             break;         }          //打印接收的数据         printf("%s", buf);     }      //关闭socket     close(fd_conn);     close(fd_listen);     return 0; } 

• 客户端代码

#include <sys/socket.h> #include <netinet/in.h> #include <arpa/inet.h> #include <errno.h> #include <stdio.h> #include <unistd.h> #include <string.h>  int main(void) {     const char ip[] = "127.0.0.1"; //服务器ip     const int port = 9006;         //服务器port      //创建socket，使用IP协议（PF_INET）+TCP协议（SOCK_STREAM）     int fd_conn = socket(PF_INET, SOCK_STREAM, 0);      //连接服务器     in_addr_t ip_num = inet_addr(ip);     sockaddr_in addr_server = {AF_INET, port, ip_num}; //服务器地址     connect(fd_conn, (sockaddr *)&addr_server, sizeof(addr_server));      const char message[] = "hello world!n";     for (int i = 0; i < 10; i++)     {         send(fd_conn, message, strlen(message), 0);         sleep(1);     }      //关闭socket     close(fd_conn);     return 0; }; 

UDP

• UDP客户端与服务器通信模型

• 服务器代码

#include <sys/socket.h> #include <netinet/in.h> #include <arpa/inet.h> #include <errno.h> #include <stdio.h> #include <unistd.h> #include <string.h>  int main(void) {     const char ip[] = "127.0.0.1";     const int port = 9006;      //创建socket，使用IP协议（PF_INET）+SOCK_DGRAM     int fd_socket = socket(PF_INET, SOCK_DGRAM, 0);      //绑定固定ip:port地址     in_addr_t ip_num = inet_addr(ip);     sockaddr_in addr_server = {AF_INET, port, ip_num};     bind(fd_socket, (sockaddr *)&addr_server, sizeof(addr_server));      //接收客户端数据     printf("start receiving data...n");      //存放客户端地址     sockaddr_in addr_client;     socklen_t len_addr_client = sizeof(addr_client);      char buf[4096];     while (true)     {         //接收数据         memset(buf, '', sizeof(buf));         int ret = recvfrom(fd_socket, buf, sizeof(buf) - 1, 0, (sockaddr *)&addr_client, &len_addr_client);         char *ip_client = inet_ntoa(addr_client.sin_addr);         int port_client = addr_client.sin_port;          //打印接收的数据         printf("recived from %s:%d: %sn", ip_client, port_client, buf);     }      //关闭socket     close(fd_socket);     return 0; } 

• 客户端代码

#include <sys/socket.h> #include <netinet/in.h> #include <arpa/inet.h> #include <errno.h> #include <stdio.h> #include <unistd.h> #include <string.h>  int main(void) {     const char ip[] = "127.0.0.1";     const int port = 9006;      //创建socket，使用IP协议（PF_INET）+SOCK_DGRAM     int fd_socket = socket(PF_INET, SOCK_DGRAM, 0);      //绑定固定ip:port地址     in_addr_t ip_num = inet_addr(ip);     sockaddr_in addr_server = {AF_INET, port, ip_num};     bind(fd_socket, (sockaddr *)&addr_server, sizeof(addr_server));      //接收客户端数据     printf("start receiving data...n");      //存放客户端地址     sockaddr_in addr_client;     socklen_t len_addr_client = sizeof(addr_client);      char buf[4096];     while (true)     {         //接收数据         memset(buf, '', sizeof(buf));         int ret = recvfrom(fd_socket, buf, sizeof(buf) - 1, 0, (sockaddr *)&addr_client, &len_addr_client);         char *ip_client = inet_ntoa(addr_client.sin_addr);         int port_client = addr_client.sin_port;          //打印接收的数据         printf("recived from %s:%d: %sn", ip_client, port_client, buf);     }      //关闭socket     close(fd_socket);     return 0; }