1. 概述:
该demo主要实现了linux下通过udp方式的socket通讯,相关接口介绍可以参考<<UNIX环境高级编程>>
2. 场景(服务端(一)<----(多)客户端):
1) 服务端:
输入:服务端监听的port;
接收到客户端发送的消息,打印到终端,并且回复客户端"ok"
2) 客户端:
输入:客户端的port,以及服务端ip和port;
输入消息内容,将消息发送给服务端,阻塞直到接收到服务端的返回信息,并打印到终端(超时未接收到时,报错);
当输入消息内容为"exit"时,选择退出客户端进程
3. 测试:
UDP 服务端
客户端1
客户端2
/*
demo_udp_server.c
网络编程demo(udp服务端)
*/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include "lpm.h"
int main(int argc, char **argv){
int ret;
int server_fd = -1;
char server_port[8];
char buf[MAX_BUF];
printf(RED BLINK"UDP 服务端\n"NONE);
printf("请输入服务端 port\t");
scanf("%s", server_port);
printf("\n");
/*
协议域 : AF_INET(IPV4) AF_INET6(IPV6) AF_LOCAL AF_ROUTE 等等
socket类型 : SOCK_STREAM(TCP) SOCK_DGRAM(UDP) 等等
0 : 表示协议域和socket类型选择默认的协议, 通常是0
*/
server_fd = socket(AF_INET, SOCK_DGRAM, 0);
if(server_fd < 0){
/*printf("socket:%s\n", strerror(errno));*/
perror("socket:");
return -1;
}
/*
应用协议 : SOL_SOCKET(套接字) IPPROTO_TCP IPPROTO_IP...
设置项 : SO_REUSEADDR(是否可以重用bind的地址)...
opt : 一些设置项指的是开关...
*/
int opt = 1;
ret = setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR, (void *)&opt, sizeof(opt));
if(ret < 0){
perror("setsockopt");
close(server_fd);
return -1;
}
struct sockaddr_in server_addr;
memset(&server_addr, 0x0, sizeof(struct sockaddr_in));
server_addr.sin_family = AF_INET;
server_addr.sin_port = htons(atoi(server_port));
server_addr.sin_addr.s_addr = htonl(INADDR_ANY);
ret = bind(server_fd, (struct sockaddr*)&server_addr, sizeof(server_addr));
if(ret < 0){
perror("bind:");
close(server_fd);
return -1;
}
char IP[32];
int addrLen = sizeof(struct sockaddr);
struct sockaddr_in client_addr;
while(1){
memset(buf, 0x0, sizeof(buf));
memset(&client_addr, 0x0, sizeof(struct sockaddr_in));
ret = recvfrom(server_fd, buf, sizeof(buf), 0, (struct sockaddr *)&client_addr,
(socklen_t *)&addrLen);
if(ret < 0){
perror("recvfrom:");
continue;
}
memset(IP, 0x0, sizeof(IP));
inet_ntop(AF_INET, (void *)&client_addr.sin_addr.s_addr, IP, sizeof(IP));
printf("客户端 ip \t%s\n", IP);
printf("客户端 port\t%d\n", ntohs(client_addr.sin_port));
printf("消息 \t%s\n", buf);
printf("\n");
ret = sendto(server_fd, OK, strlen(OK), 0, (struct sockaddr *)&client_addr,
sizeof(struct sockaddr));
if(ret < 0){
perror("sendto:");
continue;
}
}
close(server_fd);
return 0;
}
/*
demo_udp_client.c
网络编程demo(udp客户端)
*/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include "lpm.h"
int main(int argc, char **argv){
int ret;
int client_fd = -1;
char client_port[8];
char server_ip[32];
char server_port[8];
char buf[MAX_BUF];
printf(RED BLINK"UDP 客户端\n"NONE);
printf("请输入客户端 port\t");
scanf("%s", client_port);
printf("请输入服务端 ip \t");
scanf("%s", server_ip);
printf("请输入服务端 port\t");
scanf("%s", server_port);
printf("\n");
/*
协议域 : AF_INET(IPV4) AF_INET6(IPV6) AF_LOCAL AF_ROUTE 等等
socket类型 : SOCK_STREAM(TCP) SOCK_DGRAM(UDP) 等等
0 : 表示协议域和socket类型选择默认的协议, 通常是0
*/
client_fd = socket(AF_INET, SOCK_DGRAM, 0);
if(client_fd < 0){
/*printf("socket:%s\n", strerror(errno));*/
perror("socket:");
return -1;
}
/*
应用协议 : SOL_SOCKET(套接字) IPPROTO_TCP IPPROTO_IP...
设置项 : SO_REUSEADDR(是否可以重用bind的地址)...
opt : 一些设置项指的是开关...
*/
int opt = 1;
ret = setsockopt(client_fd, SOL_SOCKET, SO_REUSEADDR, (void *)&opt, sizeof(opt));
if(ret < 0){
perror("setsockopt");
close(client_fd);
return -1;
}
/*
设置项 : SO_RCVTIMEO(为recvfrom设置超时时间)...
*/
struct timeval tv;
tv.tv_sec = RECV_TIME_OUT;
tv.tv_usec = 0;
ret = setsockopt(client_fd, SOL_SOCKET, SO_RCVTIMEO, (void *)&tv, sizeof(tv));
if(ret < 0){
perror("setsockopt");
close(client_fd);
return -1;
}
struct sockaddr_in client_addr;
memset(&client_addr, 0x0, sizeof(struct sockaddr_in));
client_addr.sin_family = AF_INET;
client_addr.sin_port = htons(atoi(client_port));
client_addr.sin_addr.s_addr = htonl(INADDR_ANY);
ret = bind(client_fd, (struct sockaddr*)&client_addr, sizeof(client_addr));
if(ret < 0){
perror("bind:");
close(client_fd);
return -1;
}
struct sockaddr_in server_addr;
memset(&server_addr, 0x0, sizeof(struct sockaddr_in));
server_addr.sin_family = AF_INET;
server_addr.sin_port = htons(atoi(server_port));
inet_pton(AF_INET, server_ip, (void *)&(server_addr.sin_addr.s_addr));
while(1){
memset(buf, 0x0, sizeof(buf));
printf("请输入消息\t");
scanf("%s", buf);
ret = sendto(client_fd, buf, strlen(buf), 0, (struct sockaddr *)&server_addr,
sizeof(struct sockaddr));
if(ret < 0){
perror("sendto:");
continue;
}
if(strlen(buf) > 0 && strncmp(buf, EXIT, strlen(buf)) == 0){
break;
}
memset(buf, 0x0, sizeof(buf));
ret = recvfrom(client_fd, buf, sizeof(buf), 0, NULL, NULL);
if(ret > 0){
printf("%s\n", buf);
printf("\n");
}
else{
perror("recvfrom:");
continue;
}
}
close(client_fd);
return 0;
}
/*
lpm.h
*/
#ifndef _LPM_H_
#define _LPM_H_
#define NONE "\e[0m"
#define BLACK "\e[0;30m"
#define L_BLACK "\e[1;30m"
#define RED "\e[0;31m"
#define L_RED "\e[1;31m"
#define GREEN "\e[0;32m"
#define L_GREEN "\e[1;32m"
#define BROWN "\e[0;33m"
#define YELLOW "\e[1;33m"
#define BLUE "\e[0;34m"
#define L_BLUE "\e[1;34m"
#define PURPLE "\e[0;35m"
#define L_PURPLE "\e[1;35m"
#define CYAN "\e[0;36m"
#define L_CYAN "\e[1;36m"
#define GRAY "\e[0;37m"
#define WHITE "\e[1;37m"
#define BOLD "\e[1m"
#define UNDERLINE "\e[4m"
#define BLINK "\e[5m"
#define REVERSE "\e[7m"
#define HIDE "\e[8m"
#define CLEAR "\e[2J"
#define CLRLINE "\r\e[K" //or "\e[1K\r"
#define MAX_BUF 64
#define RECV_TIME_OUT 3
#define MAX_LISTEN 1
#define MAX_ACCEPT 2
#define OK "ok"
#define EXIT "exit"
#define ERROR "error"
#define LOG() printf("[%s %s] %s: %s: %d\n", __DATE__, __TIME__, __FILE__, __func__, __LINE__)
#endif
#Makefile
CC := gcc
INCLUDE = -I /home/demo/include/
all:
$(CC) demo_udp_server.c $(INCLUDE) -o demo_udp_server -Wall -Werror
$(CC) demo_udp_client.c $(INCLUDE) -o demo_udp_client -Wall -Werror
clean:
rm demo_udp_server demo_udp_client