一。广播
服务端向192.168.1.1~192.168.1.254的所有IP的9000端口发送数据
服务端
1 #include <stdio.h>
2 #include <unistd.h>
3 #include <stdlib.h>
4 #include <sys/socket.h>
5 #include <string.h>
6 #include <arpa/inet.h>
7 #include <net/if.h>
8
9 #define SERVER_PORT 8000 //服务器端口
10 #define MAXLINE 1500
11
12 #define BROADCAST_IP "192.168.1.255" //广播地址
13 #define CLIENT_PORT 9000 //广播的端口
14
15 int main(void)
16 {
17 int sockfd;
18 struct sockaddr_in serveraddr, clientaddr;
19 char buf[MAXLINE];
20
21 /* 构造用于UDP通信的套接字 */
22 sockfd = socket(AF_INET, SOCK_DGRAM, 0);
23
24 bzero(&serveraddr, sizeof(serveraddr));
25 serveraddr.sin_family = AF_INET; /* IPv4 */
26 serveraddr.sin_addr.s_addr = htonl(INADDR_ANY); /* 本地任意IP INADDR_ANY = 0 */
27 serveraddr.sin_port = htons(SERVER_PORT);
28
29 bind(sockfd, (struct sockaddr *)&serveraddr, sizeof(serveraddr));
30
31 int flag = 1;
32 setsockopt(sockfd, SOL_SOCKET, SO_BROADCAST, &flag, sizeof(flag)); //设置套接字打开广播权限
33
34 /*构造 client 地址 IP+端口 192.168.1.255+9000 */
35 bzero(&clientaddr, sizeof(clientaddr));
36 clientaddr.sin_family = AF_INET;
37 inet_pton(AF_INET, BROADCAST_IP, &clientaddr.sin_addr.s_addr);
38 clientaddr.sin_port = htons(CLIENT_PORT);
39
40 int i = 0;
41 while (1) {
42 sprintf(buf, "this is the %d datagram\n", i++);
43 //fgets(buf, sizeof(buf), stdin);
44 sendto(sockfd, buf, strlen(buf), 0, (struct sockaddr *)&clientaddr, sizeof(clientaddr));//发送数据
45 sleep(1);
46 }
47 close(sockfd);
48 return 0;
49 }
客户端
1 #include <stdio.h> 2 #include <unistd.h> 3 #include <string.h> 4 #include <sys/socket.h> 5 #include <arpa/inet.h> 6 7 #define SERVER_PORT 8000 8 #define MAXLINE 4096 9 #define CLIENT_PORT 9000 10 11 int main(int argc, char *argv[]) 12 { 13 struct sockaddr_in localaddr; 14 int confd; 15 ssize_t len; 16 char buf[MAXLINE]; 17 18 //1.创建一个socket 19 confd = socket(AF_INET, SOCK_DGRAM, 0); 20 21 //2.初始化本地端地址 22 bzero(&localaddr, sizeof(localaddr)); 23 localaddr.sin_family = AF_INET; 24 inet_pton(AF_INET, "0.0.0.0" , &localaddr.sin_addr.s_addr); 25 localaddr.sin_port = htons(CLIENT_PORT); 26 27 int ret = bind(confd, (struct sockaddr *)&localaddr, sizeof(localaddr)); //显式绑定不能省略 28 if (ret == 0) 29 printf("...bind ok...\n"); 30 31 while (1) { 32 len = recvfrom(confd, buf, sizeof(buf), 0, NULL, 0); //接收数据 33 write(STDOUT_FILENO, buf, len); 34 } 35 close(confd); 36 37 return 0; 38 }
二。组播
服务端向所有加入239.0.0.2多播组的所有IP的9000端口发送数据
服务端
1 #include <stdio.h>
2 #include <unistd.h>
3 #include <string.h>
4 #include <arpa/inet.h>
5 #include <net/if.h>
6
7 #define SERVER_PORT 8000
8 #define CLIENT_PORT 9000
9 #define MAXLINE 1500
10
11 #define GROUP "239.0.0.2"
12
13 int main(void)
14 {
15 int sockfd;
16 struct sockaddr_in serveraddr, clientaddr;
17 char buf[MAXLINE];
18 struct ip_mreqn group;
19
20 /*
21 struct ip_mreqn {
22 struct in_addr imr_multiaddr; /* IP multicast address of group */
23 struct in_addr imr_address; /* local IP address of interface */
24 int imr_ifindex; /* Interface index */
25 };*/
26
27 sockfd = socket(AF_INET, SOCK_DGRAM, 0); /* 构造用于UDP通信的套接字 */
28
29 bzero(&serveraddr, sizeof(serveraddr));
30 serveraddr.sin_family = AF_INET; /* IPv4 */
31 serveraddr.sin_addr.s_addr = htonl(INADDR_ANY); /* 本地任意IP INADDR_ANY = 0 */
32 serveraddr.sin_port = htons(SERVER_PORT);
33
34 bind(sockfd, (struct sockaddr *)&serveraddr, sizeof(serveraddr));
35
36 inet_pton(AF_INET, GROUP, &group.imr_multiaddr); /* 设置组地址 */
37 inet_pton(AF_INET, "0.0.0.0", &group.imr_address); /* 本地任意IP */
38 group.imr_ifindex = if_nametoindex("eth0"); /* 给出网卡名,转换为对应编号: eth0 --> 编号 命令:ip ad */
39
40 setsockopt(sockfd, IPPROTO_IP, IP_MULTICAST_IF, &group, sizeof(group)); /* 组播权限 */
41
42 bzero(&clientaddr, sizeof(clientaddr)); /* 构造 client 地址 IP+端口 */
43 clientaddr.sin_family = AF_INET;
44 inet_pton(AF_INET, GROUP, &clientaddr.sin_addr.s_addr); /* IPv4 239.0.0.2+9000 */
45 clientaddr.sin_port = htons(CLIENT_PORT);
46
47 int i = 0;
48 while (1) {
49 sprintf(buf, "this is the %d datagram\n", i++);
50 //fgets(buf, sizeof(buf), stdin);
51 sendto(sockfd, buf, strlen(buf), 0, (struct sockaddr *)&clientaddr, sizeof(clientaddr)); //向多播组9000端口发送数据
52 sleep(1);
53 }
54
55 close(sockfd);
56
57 return 0;
58 }
客户端
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <arpa/inet.h>
#include <net/if.h>
#define SERVER_PORT 8000
#define CLIENT_PORT 9000
#define GROUP "239.0.0.2" //组播地址
int main(int argc, char *argv[])
{
struct sockaddr_in localaddr;
int confd;
ssize_t len;
char buf[BUFSIZ];
struct ip_mreqn group; /* 组播结构体 */
confd = socket(AF_INET, SOCK_DGRAM, 0);
bzero(&localaddr, sizeof(localaddr)); /* 初始化 */
localaddr.sin_family = AF_INET;
inet_pton(AF_INET, "0.0.0.0" , &localaddr.sin_addr.s_addr);
localaddr.sin_port = htons(CLIENT_PORT);
bind(confd, (struct sockaddr *)&localaddr, sizeof(localaddr));
inet_pton(AF_INET, GROUP, &group.imr_multiaddr); /* 设置组地址 */
inet_pton(AF_INET, "0.0.0.0", &group.imr_address); /* 使用本地任意IP添加到组播组 */
group.imr_ifindex = if_nametoindex("eth0"); /* 通过网卡名-->编号 ip ad */
setsockopt(confd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &group, sizeof(group));/* 设置client 加入多播组 */
while (1) {
len = recvfrom(confd, buf, sizeof(buf), 0, NULL, 0); //接收数据
write(STDOUT_FILENO, buf, len);
}
close(confd);
return 0;
}