Linux 绑定与 SO_BINDTODEVICE 套接字
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bind vs SO_BINDTODEVICE socket
提问by Ami DATA
I'm running a project on linux (ubuntu 13.10) which uses raw socket connecting to a device.
我正在 linux (ubuntu 13.10) 上运行一个项目，它使用连接到设备的原始套接字。
Here is my code:
这是我的代码：
/* builed socket */
if ((sockfd = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL))) == -1) {
perror("listener: socket");
return -1;
}
/* Set interface to promiscuous mode */
strncpy(ifopts.ifr_name, ifName, IFNAMSIZ-1);
ioctl(sockfd, SIOCGIFFLAGS, &ifopts);
ifopts.ifr_flags |= IFF_PROMISC;
ioctl(sockfd, SIOCSIFFLAGS, &ifopts);
/* Allow the socket to be reused - incase connection is closed prematurely */
if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &sockopt, sizeof sockopt) == -1) {
perror("setsockopt");
close(sockfd);
return -2;
}
However I have 2 NIC cards on my computer and I would like to listen only to one of them. lets say etho. I found two options bind and SO_BINDTODEVICE as follows:
但是，我的计算机上有 2 个 NIC 卡，我只想听其中一个。让我们说精神。我发现两个选项 bind 和 SO_BINDTODEVICE 如下：
/* option 1. Bind to device */
if (setsockopt(sockfd, SOL_SOCKET, SO_BINDTODEVICE, ifName, IFNAMSIZ-1) == -1) {
perror("SO_BINDTODEVICE");
close(sockfd);
return -4;
}
/* option 2. Bind to device */
memset(&sock_address, 0, sizeof(sock_address));
sock_address.sll_family = PF_PACKET;
sock_address.sll_protocol = htons(ETH_P_ALL);
sock_address.sll_ifindex = if_nametoindex(ifName);
if (bind(sockfd, (struct sockaddr*) &sock_address, sizeof(sock_address)) < 0) {
perror("bind failed\n");
close(sockfd);
return -4;
}
Only bind works. So my question is what is the difference between the two ?
只有绑定有效。所以我的问题是两者之间有什么区别？
回答by thuovila
From the Linux man-page man 7 socketfor socket option SO_BINDTODEVICE:
从 Linux 手册页man 7 socketfor socket option SO_BINDTODEVICE：
Note that this works only for some socket types, particularly AF_INET sockets. It is not supported for packet sockets (use normal bind(2) there).
请注意，这仅适用于某些套接字类型，尤其是 AF_INET 套接字。数据包套接字不支持它（在那里使用普通的 bind(2)）。
回答by snake_xy
here is the work version.
这是工作版。
{
struct ifreq if_bind;
strncpy(if_bind.ifr_name, ifName.c_str(), IFNAMSIZ);
if(setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, (char *)&if_bind, sizeof(if_bind)) < 0) {
}
}
