如何在 Linux 中使用 C 进行 UDP 广播？
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How to UDP Broadcast with C in Linux?
提问by Daniel Silveira
How to UDP Broadcast with C in Linux?
如何在 Linux 中使用 C 进行 UDP 广播？
回答by unwind
Typically using the Berkeley sockets API, to sendto()one or more datagrams to a known broadcast-classIP address.
通常使用 Berkeley 套接字 API，将sendto()一个或多个数据报发送到一个已知的广播类IP 地址。
回答by shodanex
Unwind has it right, except you should use 'sendto'
放松是正确的，除了你应该使用“发送”
Here is an example, that assumes you already have a socket. It was taken from clamav
这是一个示例，假设您已经有一个套接字。它取自clamav
static void
broadcast(const char *mess)
{
struct sockaddr_in s;
if(broadcastSock < 0)
return;
memset(&s, '#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <time.h>
#include <string.h>
#include <stdio.h>
#include <unistd.h>
#define BYE_OFFICE 12346
#define HELLO_PORT 12345
#define HELLO_GROUP "225.0.0.37"
int main(int argc, char *argv[])
{
struct sockaddr_in addr;
struct sockaddr_in addr2;
int fd;
int fd2;
char *message = "Hello, World!";
char *message2 = "Bye, Office!";
if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
{
perror("socket");
exit(1);
}
if ((fd2 = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
{
perror("socket");
exit(1);
}
/* set up destination address */
memset(&addr,0,sizeof(addr));
addr.sin_family = AF_INET;
addr.sin_addr.s_addr = inet_addr(HELLO_GROUP);
addr.sin_port=htons(HELLO_PORT);
memset(&addr2,0,sizeof(addr2));
addr2.sin_family = AF_INET;
addr2.sin_addr.s_addr = inet_addr(HELLO_GROUP);
addr2.sin_port=htons(BYE_OFFICE);
while (1)
{
if (sendto(fd, message, strlen(message), 0,(struct sockaddr *) &addr, sizeof(addr)) < 0)
{
perror("sendto");
exit(1);
}
sleep(3);
if (sendto(fd2, message2, strlen(message2), 0,(struct sockaddr *) &addr2, sizeof(addr2)) < 0)
{
perror("sendto2");
exit(1);
}
sleep(3);
}
}
', sizeof(struct sockaddr_in));
s.sin_family = AF_INET;
s.sin_port = (in_port_t)htons(tcpSocket ? tcpSocket : 3310);
s.sin_addr.s_addr = htonl(INADDR_BROADCAST);
cli_dbgmsg("broadcast %s to %d\n", mess, broadcastSock);
if(sendto(broadcastSock, mess, strlen(mess), 0, (struct sockaddr *)&s, sizeof(struct sockaddr_in)) < 0)
perror("sendto");
}
回答by shodanex
I wrote udp multicast server recently for testing. To subscribe to multicast you would subscribe your client to Multicast group 225.0.0.37 port 12346 and port 12345 (2 feeds - one feeds sends "Hello, World!" the other one "Bye, Office!").
我最近写了 udp 多播服务器进行测试。要订阅多播，您需要为客户端订阅多播组 225.0.0.37 端口 12346 和端口 12345（2 个提要 - 一个提要发送“Hello, World！”另一个提要“Bye, Office!”）。
I've been using it for testing my client, both client and server run on the same box so there might be bits that may not work but give it a try first.
我一直在用它来测试我的客户端，客户端和服务器都在同一个机器上运行，所以可能有些位可能不起作用，但先试一试。
bcast_sock = socket(AF_INET, SOCK_DGRAM, 0);
int broadcastEnable=1;
int ret=setsockopt(bcast_sock, SOL_SOCKET, SO_BROADCAST, &broadcastEnable, sizeof(broadcastEnable));
/* Add other code, sockaddr, sendto() etc. */
回答by skoylu
In many IP stack, such as Linux, this code does not work. Your socket must have broadcast permissions. Try this:
在许多 IP 堆栈中，例如 Linux，此代码不起作用。您的套接字必须具有广播权限。尝试这个：
##代码##