英文:
Is it possible to receive raw ethernet frames in Linux without specifying an interface?
问题
我正在使用mdlayhers（golang）库来处理原始以太网帧，以接收和处理网络设备上的LLDP数据包。我想监视大量接口（最多128个）的LLDP帧。
在Linux中，我认为不需要指定要捕获设备数据的接口，但我可能错了。是否可以通过在go中绑定到AF_PACKET来接收所有接口上的原始以太网帧？即，在raw.ListenPacket中是否有指定通配符接口的方法，或者我最好为每个接口创建一个新的goroutine？
英文:
I'm using mdlayhers (golang) libraries to handle raw ethernet frames to receive and process LLDP packets on a networking device. I'd like to monitor a large number of interfaces (up to 128) for LLDP frames.
In Linux I don't believe it's required to specify an interface to capture device data, but I could be wrong. Is it possible to receive raw ethernet frames across all interfaces by, for example, binding to AF_PACKET in go? I.e. Is there way to specify a wildcard interface in raw.ListenPacket or am I best creating a new goroutine for each interface?
答案1
得分: 1
是的，你可以。我相信这就是你要找的代码：
package main
import (
"fmt"
"net"
"os"
"syscall"
)
func main() {
fd, err := syscall.Socket(syscall.AF_PACKET, syscall.SOCK_RAW, int(htons(syscall.ETH_P_ALL)))
if err != nil {
fmt.Fprintf(os.Stderr, "syscall socket: %s", err.Error())
os.Exit(1)
}
// 创建一个32KB的缓冲区
buf := make([]byte, 1<<16)
for {
len, sockaddr, err := syscall.Recvfrom(fd, buf, 0)
if err != nil {
fmt.Fprintf(os.Stderr, "syscall recvfrom: %s", err.Error())
os.Exit(1)
}
if llsa, ok := sockaddr.(*syscall.SockaddrLinklayer); ok {
inter, err := net.InterfaceByIndex(llsa.Ifindex)
if err != nil {
fmt.Fprintf(os.Stderr, "interface from ifindex: %s", err.Error())
os.Exit(1)
}
fmt.Print(inter.Name + ": ")
}
fmt.Printf("% X\n", buf[:len])
}
}
// htons函数将一个short（uint16）从主机字节序转换为网络字节序。
func htons(i uint16) uint16 {
return (i<<8)&0xff00 | i>>8
}
希望对你有帮助！
英文:
Yes you can. I believe this is what you are looking for:
package main
import (
"fmt"
"net"
"os"
"syscall"
)
func main() {
fd, err := syscall.Socket(syscall.AF_PACKET, syscall.SOCK_RAW, int(htons(syscall.ETH_P_ALL)))
if err != nil {
fmt.Fprintf(os.Stderr, "syscall socket: %s", err.Error())
os.Exit(1)
}
// Make a 32KB buffer
buf := make([]byte, 1<<16)
for {
len, sockaddr, err := syscall.Recvfrom(fd, buf, 0)
if err != nil {
fmt.Fprintf(os.Stderr, "syscall recvfrom: %s", err.Error())
os.Exit(1)
}
if llsa, ok := sockaddr.(*syscall.SockaddrLinklayer); ok {
inter, err := net.InterfaceByIndex(llsa.Ifindex)
if err != nil {
fmt.Fprintf(os.Stderr, "interface from ifindex: %s", err.Error())
os.Exit(1)
}
fmt.Print(inter.Name + ": ")
}
fmt.Printf("% X\n", buf[:len])
}
}
// htons converts a short (uint16) from host-to-network byte order.
func htons(i uint16) uint16 {
return (i<<8)&0xff00 | i>>8
}
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