1 files changed, 229 insertions, 0 deletions
diff --git a/libgo/go/syscall/netlink_linux.go b/libgo/go/syscall/netlink_linux.go
new file mode 100644
index 00000000000..4ee78d62f25
--- /dev/null
+++ b/libgo/go/syscall/netlink_linux.go
@@ -0,0 +1,229 @@
+// Copyright 2011 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.
+
+// Netlink sockets and messages
+
+package syscall
+
+import (
+	"unsafe"
+)
+
+// Round the length of a netlink message up to align it properly.
+func nlmAlignOf(msglen int) int {
+	return (msglen + NLMSG_ALIGNTO - 1) & ^(NLMSG_ALIGNTO - 1)
+}
+
+// Round the length of a netlink route attribute up to align it
+// properly.
+func rtaAlignOf(attrlen int) int {
+	return (attrlen + RTA_ALIGNTO - 1) & ^(RTA_ALIGNTO - 1)
+}
+
+// NetlinkRouteRequest represents the request message to receive
+// routing and link states from the kernel.
+type NetlinkRouteRequest struct {
+	Header NlMsghdr
+	Data   RtGenmsg
+}
+
+func (rr *NetlinkRouteRequest) toWireFormat() []byte {
+	b := make([]byte, rr.Header.Len)
+	b[0] = byte(rr.Header.Len)
+	b[1] = byte(rr.Header.Len >> 8)
+	b[2] = byte(rr.Header.Len >> 16)
+	b[3] = byte(rr.Header.Len >> 24)
+	b[4] = byte(rr.Header.Type)
+	b[5] = byte(rr.Header.Type >> 8)
+	b[6] = byte(rr.Header.Flags)
+	b[7] = byte(rr.Header.Flags >> 8)
+	b[8] = byte(rr.Header.Seq)
+	b[9] = byte(rr.Header.Seq >> 8)
+	b[10] = byte(rr.Header.Seq >> 16)
+	b[11] = byte(rr.Header.Seq >> 24)
+	b[12] = byte(rr.Header.Pid)
+	b[13] = byte(rr.Header.Pid >> 8)
+	b[14] = byte(rr.Header.Pid >> 16)
+	b[15] = byte(rr.Header.Pid >> 24)
+	b[16] = byte(rr.Data.Family)
+	return b
+}
+
+func newNetlinkRouteRequest(proto, seq, family int) []byte {
+	rr := &NetlinkRouteRequest{}
+	rr.Header.Len = uint32(NLMSG_HDRLEN + SizeofRtGenmsg)
+	rr.Header.Type = uint16(proto)
+	rr.Header.Flags = NLM_F_DUMP | NLM_F_REQUEST
+	rr.Header.Seq = uint32(seq)
+	rr.Data.Family = uint8(family)
+	return rr.toWireFormat()
+}
+
+// NetlinkRIB returns routing information base, as known as RIB,
+// which consists of network facility information, states and
+// parameters.
+func NetlinkRIB(proto, family int) ([]byte, int) {
+	var (
+		s     int
+		e     int
+		lsanl SockaddrNetlink
+		seq   int
+		tab   []byte
+	)
+
+	s, e = Socket(AF_NETLINK, SOCK_RAW, 0)
+	if e != 0 {
+		return nil, e
+	}
+	defer Close(s)
+
+	lsanl.Family = AF_NETLINK
+	e = Bind(s, &lsanl)
+	if e != 0 {
+		return nil, e
+	}
+
+	seq++
+	wb := newNetlinkRouteRequest(proto, seq, family)
+	e = Sendto(s, wb, 0, &lsanl)
+	if e != 0 {
+		return nil, e
+	}
+
+	for {
+		var (
+			rb  []byte
+			nr  int
+			lsa Sockaddr
+		)
+
+		rb = make([]byte, Getpagesize())
+		nr, _, e = Recvfrom(s, rb, 0)
+		if e != 0 {
+			return nil, e
+		}
+		if nr < NLMSG_HDRLEN {
+			return nil, EINVAL
+		}
+		rb = rb[:nr]
+		tab = append(tab, rb...)
+
+		msgs, _ := ParseNetlinkMessage(rb)
+		for _, m := range msgs {
+			if lsa, e = Getsockname(s); e != 0 {
+				return nil, e
+			}
+			switch v := lsa.(type) {
+			case *SockaddrNetlink:
+				if m.Header.Seq != uint32(seq) || m.Header.Pid != v.Pid {
+					return nil, EINVAL
+				}
+			default:
+				return nil, EINVAL
+			}
+			if m.Header.Type == NLMSG_DONE {
+				goto done
+			}
+			if m.Header.Type == NLMSG_ERROR {
+				return nil, EINVAL
+			}
+		}
+	}
+
+done:
+	return tab, 0
+}
+
+// NetlinkMessage represents the netlink message.
+type NetlinkMessage struct {
+	Header NlMsghdr
+	Data   []byte
+}
+
+// ParseNetlinkMessage parses buf as netlink messages and returns
+// the slice containing the NetlinkMessage structs.
+func ParseNetlinkMessage(buf []byte) ([]NetlinkMessage, int) {
+	var (
+		h    *NlMsghdr
+		dbuf []byte
+		dlen int
+		e    int
+		msgs []NetlinkMessage
+	)
+
+	for len(buf) >= NLMSG_HDRLEN {
+		h, dbuf, dlen, e = netlinkMessageHeaderAndData(buf)
+		if e != 0 {
+			break
+		}
+		m := NetlinkMessage{}
+		m.Header = *h
+		m.Data = dbuf[:int(h.Len)-NLMSG_HDRLEN]
+		msgs = append(msgs, m)
+		buf = buf[dlen:]
+	}
+
+	return msgs, e
+}
+
+func netlinkMessageHeaderAndData(buf []byte) (*NlMsghdr, []byte, int, int) {
+	h := (*NlMsghdr)(unsafe.Pointer(&buf[0]))
+	if int(h.Len) < NLMSG_HDRLEN || int(h.Len) > len(buf) {
+		return nil, nil, 0, EINVAL
+	}
+	return h, buf[NLMSG_HDRLEN:], nlmAlignOf(int(h.Len)), 0
+}
+
+// NetlinkRouteAttr represents the netlink route attribute.
+type NetlinkRouteAttr struct {
+	Attr  RtAttr
+	Value []byte
+}
+
+// ParseNetlinkRouteAttr parses msg's payload as netlink route
+// attributes and returns the slice containing the NetlinkRouteAttr
+// structs.
+func ParseNetlinkRouteAttr(msg *NetlinkMessage) ([]NetlinkRouteAttr, int) {
+	var (
+		buf   []byte
+		a     *RtAttr
+		alen  int
+		vbuf  []byte
+		e     int
+		attrs []NetlinkRouteAttr
+	)
+
+	switch msg.Header.Type {
+	case RTM_NEWLINK, RTM_DELLINK:
+		buf = msg.Data[SizeofIfInfomsg:]
+	case RTM_NEWADDR, RTM_DELADDR:
+		buf = msg.Data[SizeofIfAddrmsg:]
+	case RTM_NEWROUTE, RTM_DELROUTE:
+		buf = msg.Data[SizeofRtMsg:]
+	default:
+		return nil, EINVAL
+	}
+
+	for len(buf) >= SizeofRtAttr {
+		a, vbuf, alen, e = netlinkRouteAttrAndValue(buf)
+		if e != 0 {
+			break
+		}
+		ra := NetlinkRouteAttr{}
+		ra.Attr = *a
+		ra.Value = vbuf[:int(a.Len)-SizeofRtAttr]
+		attrs = append(attrs, ra)
+		buf = buf[alen:]
+	}
+
+	return attrs, 0
+}
+
+func netlinkRouteAttrAndValue(buf []byte) (*RtAttr, []byte, int, int) {
+	h := (*RtAttr)(unsafe.Pointer(&buf[0]))
+	if int(h.Len) < SizeofRtAttr || int(h.Len) > len(buf) {
+		return nil, nil, 0, EINVAL
+	}
+	return h, buf[SizeofRtAttr:], rtaAlignOf(int(h.Len)), 0
+}