c++ - "Destination address required"尝试通过 SOCK_RAW 套接字发送数据时

Question

我正在尝试发送数据包(不是 ip 数据包，而是 EAP 请求标识)，但是 send() 函数返回 -1。

    int sockfd = socket(AF_INET, SOCK_RAW, 0);
printf("socket: %d\n", sockfd);
struct sockaddr_in sock;
printf("creating packet\n");
char packet[27];
memcpy(packet + 0, (u_char* ) ethernet->ether_dhost, 6);
memcpy(packet + 6, (u_char* ) ethernet->ether_shost, 6);
memcpy(packet + 12, (u_char* ) ethernet + 12, 2);
memcpy(packet + 14, (u_char *)reqid, 1);
memcpy(packet + 15, (u_char *)reqid+1, 1);
memcpy(packet + 16, (u_char *)reqid+2, 4);
memcpy(packet + 20, (u_char *)reqid+6, 1);
memcpy(packet + 21, (u_char *)reqid+7, 1);
memcpy(packet + 22, (u_char *)reqid+8, 4);
memcpy(packet + 26, (u_char *)reqid+12, 1);
printf("sending packet\n");
if(send(sockfd, packet, sizeof(packet), 0) == -1)
{
     printf("packet not sent\n");
     //return;
}

数据包由以太网数据包和请求标识组成。 我知道数据包很好，每个值都在正确的位置。但是 send() 函数失败了。
errno show "Destination address required"并且 sockfd 值为 4。 顺便说一句，这是在 FreeBSD 上。
谢谢 编辑: 我没有目的地的 IP 地址。我只有它的MAC地址。

Answer 1

来自手册页:

The send() call may be used only when the socket is in a connected state (so that the intended recipient is known).

我相信你想要sendto，而不是send。