2016-07-22 20:15:38 +02:00
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// Copyright 2011 The Go Authors. All rights reserved.
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2011-09-16 17:47:21 +02:00
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Netlink sockets and messages
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package syscall
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2013-01-29 21:52:43 +01:00
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import "unsafe"
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2011-09-16 17:47:21 +02:00
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// Round the length of a netlink message up to align it properly.
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func nlmAlignOf(msglen int) int {
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return (msglen + NLMSG_ALIGNTO - 1) & ^(NLMSG_ALIGNTO - 1)
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}
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// Round the length of a netlink route attribute up to align it
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// properly.
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func rtaAlignOf(attrlen int) int {
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return (attrlen + RTA_ALIGNTO - 1) & ^(RTA_ALIGNTO - 1)
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}
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2013-01-29 21:52:43 +01:00
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// NetlinkRouteRequest represents a request message to receive routing
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// and link states from the kernel.
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2011-09-16 17:47:21 +02:00
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type NetlinkRouteRequest struct {
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Header NlMsghdr
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Data RtGenmsg
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}
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func (rr *NetlinkRouteRequest) toWireFormat() []byte {
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b := make([]byte, rr.Header.Len)
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2012-04-20 22:11:28 +02:00
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*(*uint32)(unsafe.Pointer(&b[0:4][0])) = rr.Header.Len
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*(*uint16)(unsafe.Pointer(&b[4:6][0])) = rr.Header.Type
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*(*uint16)(unsafe.Pointer(&b[6:8][0])) = rr.Header.Flags
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*(*uint32)(unsafe.Pointer(&b[8:12][0])) = rr.Header.Seq
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*(*uint32)(unsafe.Pointer(&b[12:16][0])) = rr.Header.Pid
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b[16] = byte(rr.Data.Family)
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2011-09-16 17:47:21 +02:00
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return b
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}
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func newNetlinkRouteRequest(proto, seq, family int) []byte {
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rr := &NetlinkRouteRequest{}
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rr.Header.Len = uint32(NLMSG_HDRLEN + SizeofRtGenmsg)
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rr.Header.Type = uint16(proto)
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rr.Header.Flags = NLM_F_DUMP | NLM_F_REQUEST
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rr.Header.Seq = uint32(seq)
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rr.Data.Family = uint8(family)
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return rr.toWireFormat()
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}
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2013-01-29 21:52:43 +01:00
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// NetlinkRIB returns routing information base, as known as RIB, which
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// consists of network facility information, states and parameters.
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2011-12-13 00:40:51 +01:00
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func NetlinkRIB(proto, family int) ([]byte, error) {
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s, err := Socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE)
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if err != nil {
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return nil, err
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2011-09-16 17:47:21 +02:00
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}
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defer Close(s)
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2013-01-29 21:52:43 +01:00
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lsa := &SockaddrNetlink{Family: AF_NETLINK}
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if err := Bind(s, lsa); err != nil {
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return nil, err
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2011-09-16 17:47:21 +02:00
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}
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2013-01-29 21:52:43 +01:00
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wb := newNetlinkRouteRequest(proto, 1, family)
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if err := Sendto(s, wb, 0, lsa); err != nil {
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return nil, err
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2011-09-16 17:47:21 +02:00
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}
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var tab []byte
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2015-01-15 01:27:56 +01:00
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rbNew := make([]byte, Getpagesize())
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done:
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for {
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2015-01-15 01:27:56 +01:00
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rb := rbNew
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2013-01-29 21:52:43 +01:00
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nr, _, err := Recvfrom(s, rb, 0)
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if err != nil {
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return nil, err
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2011-09-16 17:47:21 +02:00
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}
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if nr < NLMSG_HDRLEN {
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return nil, EINVAL
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}
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rb = rb[:nr]
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tab = append(tab, rb...)
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2013-01-29 21:52:43 +01:00
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msgs, err := ParseNetlinkMessage(rb)
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if err != nil {
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return nil, err
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}
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2011-09-16 17:47:21 +02:00
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for _, m := range msgs {
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2013-01-29 21:52:43 +01:00
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lsa, err := Getsockname(s)
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if err != nil {
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return nil, err
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2011-09-16 17:47:21 +02:00
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}
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switch v := lsa.(type) {
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case *SockaddrNetlink:
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if m.Header.Seq != 1 || m.Header.Pid != v.Pid {
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2011-09-16 17:47:21 +02:00
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return nil, EINVAL
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}
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default:
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return nil, EINVAL
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}
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if m.Header.Type == NLMSG_DONE {
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break done
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2011-09-16 17:47:21 +02:00
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}
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if m.Header.Type == NLMSG_ERROR {
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return nil, EINVAL
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}
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}
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}
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2011-12-13 00:40:51 +01:00
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return tab, nil
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2011-09-16 17:47:21 +02:00
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}
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2013-01-29 21:52:43 +01:00
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// NetlinkMessage represents a netlink message.
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2011-09-16 17:47:21 +02:00
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type NetlinkMessage struct {
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Header NlMsghdr
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Data []byte
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}
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2013-01-29 21:52:43 +01:00
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// ParseNetlinkMessage parses b as an array of netlink messages and
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// returns the slice containing the NetlinkMessage structures.
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func ParseNetlinkMessage(b []byte) ([]NetlinkMessage, error) {
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var msgs []NetlinkMessage
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for len(b) >= NLMSG_HDRLEN {
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h, dbuf, dlen, err := netlinkMessageHeaderAndData(b)
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if err != nil {
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return nil, err
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2011-09-16 17:47:21 +02:00
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}
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2013-01-29 21:52:43 +01:00
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m := NetlinkMessage{Header: *h, Data: dbuf[:int(h.Len)-NLMSG_HDRLEN]}
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2011-09-16 17:47:21 +02:00
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msgs = append(msgs, m)
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2013-01-29 21:52:43 +01:00
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b = b[dlen:]
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2011-09-16 17:47:21 +02:00
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}
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2013-01-29 21:52:43 +01:00
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return msgs, nil
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2011-09-16 17:47:21 +02:00
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}
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2013-01-29 21:52:43 +01:00
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func netlinkMessageHeaderAndData(b []byte) (*NlMsghdr, []byte, int, error) {
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h := (*NlMsghdr)(unsafe.Pointer(&b[0]))
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2017-01-14 01:05:42 +01:00
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l := nlmAlignOf(int(h.Len))
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if int(h.Len) < NLMSG_HDRLEN || l > len(b) {
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2011-09-16 17:47:21 +02:00
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return nil, nil, 0, EINVAL
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}
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2017-01-14 01:05:42 +01:00
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return h, b[NLMSG_HDRLEN:], l, nil
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2011-09-16 17:47:21 +02:00
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}
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2013-01-29 21:52:43 +01:00
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// NetlinkRouteAttr represents a netlink route attribute.
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2011-09-16 17:47:21 +02:00
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type NetlinkRouteAttr struct {
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Attr RtAttr
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Value []byte
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}
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2013-01-29 21:52:43 +01:00
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// ParseNetlinkRouteAttr parses m's payload as an array of netlink
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// route attributes and returns the slice containing the
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// NetlinkRouteAttr structures.
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func ParseNetlinkRouteAttr(m *NetlinkMessage) ([]NetlinkRouteAttr, error) {
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var b []byte
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switch m.Header.Type {
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2011-10-23 21:04:37 +02:00
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case RTM_NEWLINK, RTM_DELLINK:
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2013-01-29 21:52:43 +01:00
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b = m.Data[SizeofIfInfomsg:]
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2011-10-23 21:04:37 +02:00
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case RTM_NEWADDR, RTM_DELADDR:
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2013-01-29 21:52:43 +01:00
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b = m.Data[SizeofIfAddrmsg:]
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2011-10-23 21:04:37 +02:00
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case RTM_NEWROUTE, RTM_DELROUTE:
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2013-01-29 21:52:43 +01:00
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b = m.Data[SizeofRtMsg:]
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2011-09-16 17:47:21 +02:00
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default:
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return nil, EINVAL
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}
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2013-01-29 21:52:43 +01:00
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var attrs []NetlinkRouteAttr
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for len(b) >= SizeofRtAttr {
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a, vbuf, alen, err := netlinkRouteAttrAndValue(b)
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if err != nil {
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return nil, err
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2011-09-16 17:47:21 +02:00
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}
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2013-01-29 21:52:43 +01:00
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ra := NetlinkRouteAttr{Attr: *a, Value: vbuf[:int(a.Len)-SizeofRtAttr]}
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2011-09-16 17:47:21 +02:00
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attrs = append(attrs, ra)
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2013-01-29 21:52:43 +01:00
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b = b[alen:]
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2011-09-16 17:47:21 +02:00
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}
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2011-12-13 00:40:51 +01:00
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return attrs, nil
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2011-09-16 17:47:21 +02:00
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}
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2013-01-29 21:52:43 +01:00
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func netlinkRouteAttrAndValue(b []byte) (*RtAttr, []byte, int, error) {
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a := (*RtAttr)(unsafe.Pointer(&b[0]))
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if int(a.Len) < SizeofRtAttr || int(a.Len) > len(b) {
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2011-09-16 17:47:21 +02:00
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return nil, nil, 0, EINVAL
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}
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2013-01-29 21:52:43 +01:00
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return a, b[SizeofRtAttr:], rtaAlignOf(int(a.Len)), nil
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2011-09-16 17:47:21 +02:00
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}
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