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// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build darwin dragonfly freebsd netbsd openbsd
// Package route provides basic functions for the manipulation of
// packet routing facilities on BSD variants.
//
// The package supports any version of Darwin, any version of
// DragonFly BSD, FreeBSD 7 through 11, NetBSD 6 and above, and
// OpenBSD 5.6 and above.
package route
import (
"errors"
"os"
"syscall"
)
var (
errUnsupportedMessage = errors.New("unsupported message")
errMessageMismatch = errors.New("message mismatch")
errMessageTooShort = errors.New("message too short")
errInvalidMessage = errors.New("invalid message")
errInvalidAddr = errors.New("invalid address")
)
// A RouteMessage represents a message conveying an address prefix, a
// nexthop address and an output interface.
type RouteMessage struct {
Version int // message version
Type int // message type
Flags int // route flags
Index int // interface index when atatched
Addrs []Addr // addresses
extOff int // offset of header extension
raw []byte // raw message
}
// A RIBType reprensents a type of routing information base.
type RIBType int
const (
RIBTypeRoute RIBType = syscall.NET_RT_DUMP
RIBTypeInterface RIBType = syscall.NET_RT_IFLIST
)
// FetchRIB fetches a routing information base from the operating
// system.
//
// The provided af must be an address family.
//
// The provided arg must be a RIBType-specific argument.
// When RIBType is related to routes, arg might be a set of route
// flags. When RIBType is related to network interfaces, arg might be
// an interface index or a set of interface flags. In most cases, zero
// means a wildcard.
func FetchRIB(af int, typ RIBType, arg int) ([]byte, error) {
mib := [6]int32{sysCTL_NET, sysAF_ROUTE, 0, int32(af), int32(typ), int32(arg)}
n := uintptr(0)
if err := sysctl(mib[:], nil, &n, nil, 0); err != nil {
return nil, os.NewSyscallError("sysctl", err)
}
if n == 0 {
return nil, nil
}
b := make([]byte, n)
if err := sysctl(mib[:], &b[0], &n, nil, 0); err != nil {
return nil, os.NewSyscallError("sysctl", err)
}
return b[:n], nil
}
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