net: ParseMAC cannot parse 20-octet IP over InfiniBand link-layer address

[mdlayher]

At the moment, net.ParseMAC cannot accept 20-octet IP over InfiniBand link-layer addresses, though they are correctly parsed into net.Interface.

$ ip addr show ib0
4: ib0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 4092 qdisc pfifo_fast state DOWN group default qlen 256
    link/infiniband 80:00:00:48:fe:80:00:00:00:00:00:00:00:02:c9:03:00:50:5e:d5 brd 00:ff:ff:ff:ff:12:40:1b:ff:ff:00:00:00:00:00:00:ff:ff:ff:ff

Here is an example program:

package main

import (
        "flag"
        "log"
        "net"
)

var (
        ifaceFlag = flag.String("i", "ib0", "network interface name")
)

func main() {
        ifi, err := net.InterfaceByName(*ifaceFlag)
        if err != nil {
                log.Fatal(err)
        }

        log.Printf("%s: %s", ifi.Name, ifi.HardwareAddr)

        mac, err := net.ParseMAC(ifi.HardwareAddr.String())
        if err != nil {
                log.Fatal(err)
        }

        log.Println("%s: %s", ifi.Name, mac)
}

Here is the output as of Go 1.4.2:

$ go build
$ ./ibmac 
2015/07/17 17:11:34 ib0: 80:00:00:48:fe:80:00:00:00:00:00:00:00:02:c9:03:00:50:5e:d5
2015/07/17 17:11:34 invalid MAC address: 80:00:00:48:fe:80:00:00:00:00:00:00:00:02:c9:03:00:50:5e:d5

I will submit a changelist which should fix this issue shortly.

[gopherbot]

CL https://golang.org/cl/12382 mentions this issue.