Linux TCP网络编程示例

2020年9月24日 16:56:14Linux大全评论508 views阅读模式

#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <strings.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <unistd.h>
int main(int argc, char *argv[])
{
int sockfd;
char buffer[1024];
struct sockaddr_in server_addr;
int portnumber, nbytes;
if (argc != 3) {
fprintf(stderr, "Usage:%s hostname portnumber\n\a", argv[0]);
exit(1);
}
if (inet_aton(argv[1], &server_addr.sin_addr) == 0) {
fprintf(stderr, "the hostip is not right!");
exit(1);
}
if ((portnumber = atoi(argv[2])) < 0) {
fprintf(stderr, "Usage:%s hostname portnumber\n\a", argv[0]);
exit(1);
}
// 创建套接字
if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
fprintf(stderr, "Socket Error:%s\n\a", strerror(errno));
exit(1);
}
// 填充服务器的地址信息
server_addr.sin_family = AF_INET;
server_addr.sin_port = htons(portnumber);
// 向服务器发起连接
if (connect(sockfd, (struct sockaddr *)&server_addr, sizeof(struct sockaddr)) == -1) {
fprintf(stderr, "Connect Error:%s\n\a", strerror(errno));
exit(1);
}
// 连接成功后，从服务器接收信息
if ((nbytes = read(sockfd, buffer, 1024)) == -1) {
fprintf(stderr, "Read Error:%s\n", strerror(errno));
exit(1);
}
buffer[nbytes] = '\0';
printf("I have received:%s\n", buffer);
close(sockfd);
exit(0);
}

#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <strings.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <unistd.h>
int main(int argc, char *argv[])
{
int sockfd, new_fd;
struct sockaddr_in server_addr;
struct sockaddr_in client_addr;
int sin_size, portnumber;
char hello[] = "Hello! Are you fine?\n";
if (argc != 2) {
fprintf(stderr, "Usage:%s portnumber\a\n", argv[0]);
exit(1);
}
if ((portnumber = atoi(argv[1])) < 0) {
fprintf(stderr, "Usage:%s portnumber\a\n", argv[0]);
exit(1);
}
// 创建套接字
if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
fprintf(stderr, "Socket error:%s\n\a", strerror(errno));
exit(1);
}
// 填充服务器的地址结构
bzero(&server_addr, sizeof(struct sockaddr_in));
server_addr.sin_family = AF_INET;
server_addr.sin_addr.s_addr = htonl(INADDR_ANY);
server_addr.sin_port = htons(portnumber);
// 套接字绑定地址
if (bind(sockfd, (struct sockaddr *)&server_addr, sizeof(struct sockaddr)) == -1) {
fprintf(stderr, "Bind error:%s\n\a", strerror(errno));
exit(1);
}
// 进入监听状态
if (listen(sockfd, 5) == -1) {
fprintf(stderr, "Listen error:%s\n\a", strerror(errno));
exit(1);
}
while (1) {
// 接收客户端的连接
sin_size = sizeof(struct sockaddr_in);
if ((new_fd = accept(sockfd, (struct sockaddr *)&client_addr, (socklen_t *)&sin_size)) == -1) {
fprintf(stderr, "Accept error:%s\n\a", strerror(errno));
exit(1);
}
fprintf(stderr, "Server get connection from %s\n", inet_ntoa(client_addr.sin_addr));
if (write(new_fd, hello, strlen(hello)) == -1) {
fprintf(stderr, "Write error:%s\n", strerror(errno));
exit(1);
}
close(new_fd);
}
close(sockfd);
// exit(0);
return 0;
}