Bind DNS names through /etc/hosts

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

vendor/github.com/vishvananda/netlink/bpf_linux.go

@@ -0,0 +1,53 @@
+package netlink
+
+import (
+	"unsafe"
+
+	"golang.org/x/sys/unix"
+)
+
+type BpfProgType uint32
+
+const (
+	BPF_PROG_TYPE_UNSPEC BpfProgType = iota
+	BPF_PROG_TYPE_SOCKET_FILTER
+	BPF_PROG_TYPE_KPROBE
+	BPF_PROG_TYPE_SCHED_CLS
+	BPF_PROG_TYPE_SCHED_ACT
+	BPF_PROG_TYPE_TRACEPOINT
+	BPF_PROG_TYPE_XDP
+)
+
+type BPFAttr struct {
+	ProgType    uint32
+	InsnCnt     uint32
+	Insns       uintptr
+	License     uintptr
+	LogLevel    uint32
+	LogSize     uint32
+	LogBuf      uintptr
+	KernVersion uint32
+}
+
+// loadSimpleBpf loads a trivial bpf program for testing purposes.
+func loadSimpleBpf(progType BpfProgType, ret uint32) (int, error) {
+	insns := []uint64{
+		0x00000000000000b7 | (uint64(ret) << 32),
+		0x0000000000000095,
+	}
+	license := []byte{'A', 'S', 'L', '2', '\x00'}
+	attr := BPFAttr{
+		ProgType: uint32(progType),
+		InsnCnt:  uint32(len(insns)),
+		Insns:    uintptr(unsafe.Pointer(&insns[0])),
+		License:  uintptr(unsafe.Pointer(&license[0])),
+	}
+	fd, _, errno := unix.Syscall(unix.SYS_BPF,
+		5, /* bpf cmd */
+		uintptr(unsafe.Pointer(&attr)),
+		unsafe.Sizeof(attr))
+	if errno != 0 {
+		return 0, errno
+	}
+	return int(fd), nil
+}