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[/] [openrisc/] [trunk/] [gnu-dev/] [or1k-gcc/] [libgo/] [go/] [syscall/] [netlink_linux.go] - Blame information for rev 747

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Line No. Rev Author Line
1 747 jeremybenn 
// Copyright 2011 The Go Authors.  All rights reserved.
2 
// 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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5 
// Netlink sockets and messages
6 
 
7 
package syscall
8 
 
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import (
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        "unsafe"
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)
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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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24 
// NetlinkRouteRequest represents the request message to receive
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// routing and link states from the kernel.
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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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31 
func (rr *NetlinkRouteRequest) toWireFormat() []byte {
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        b := make([]byte, rr.Header.Len)
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        b[0] = byte(rr.Header.Len)
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        b[1] = byte(rr.Header.Len >> 8)
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        b[2] = byte(rr.Header.Len >> 16)
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        b[3] = byte(rr.Header.Len >> 24)
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        b[4] = byte(rr.Header.Type)
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        b[5] = byte(rr.Header.Type >> 8)
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        b[6] = byte(rr.Header.Flags)
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        b[7] = byte(rr.Header.Flags >> 8)
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        b[8] = byte(rr.Header.Seq)
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        b[9] = byte(rr.Header.Seq >> 8)
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        b[10] = byte(rr.Header.Seq >> 16)
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        b[11] = byte(rr.Header.Seq >> 24)
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        b[12] = byte(rr.Header.Pid)
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        b[13] = byte(rr.Header.Pid >> 8)
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        b[14] = byte(rr.Header.Pid >> 16)
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        b[15] = byte(rr.Header.Pid >> 24)
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        b[16] = byte(rr.Data.Family)
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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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// NetlinkRIB returns routing information base, as known as RIB,
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// which consists of network facility information, states and
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// parameters.
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func NetlinkRIB(proto, family int) ([]byte, error) {
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        var (
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                lsanl SockaddrNetlink
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                tab   []byte
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        )
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        s, e := Socket(AF_NETLINK, SOCK_RAW, 0)
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        if e != nil {
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                return nil, e
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        }
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        defer Close(s)
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        lsanl.Family = AF_NETLINK
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        e = Bind(s, &lsanl)
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        if e != nil {
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                return nil, e
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        }
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        seq := 1
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        wb := newNetlinkRouteRequest(proto, seq, family)
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        e = Sendto(s, wb, 0, &lsanl)
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        if e != nil {
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                return nil, e
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        }
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        for {
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                var (
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                        rb  []byte
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                        nr  int
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                        lsa Sockaddr
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                )
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                rb = make([]byte, Getpagesize())
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                nr, _, e = Recvfrom(s, rb, 0)
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                if e != nil {
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                        return nil, e
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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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                msgs, _ := ParseNetlinkMessage(rb)
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                for _, m := range msgs {
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                        if lsa, e = Getsockname(s); e != nil {
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                                return nil, e
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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 != uint32(seq) || m.Header.Pid != v.Pid {
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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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                                goto done
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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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131 
done:
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        return tab, nil
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}
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// NetlinkMessage represents the netlink message.
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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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// ParseNetlinkMessage parses buf as netlink messages and returns
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// the slice containing the NetlinkMessage structs.
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func ParseNetlinkMessage(buf []byte) ([]NetlinkMessage, error) {
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        var (
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                h    *NlMsghdr
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                dbuf []byte
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                dlen int
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                e    error
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                msgs []NetlinkMessage
150 
        )
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152 
        for len(buf) >= NLMSG_HDRLEN {
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                h, dbuf, dlen, e = netlinkMessageHeaderAndData(buf)
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                if e != nil {
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                        break
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                }
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                m := NetlinkMessage{}
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                m.Header = *h
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                m.Data = dbuf[:int(h.Len)-NLMSG_HDRLEN]
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                msgs = append(msgs, m)
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                buf = buf[dlen:]
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        }
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164 
        return msgs, e
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}
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167 
func netlinkMessageHeaderAndData(buf []byte) (*NlMsghdr, []byte, int, error) {
168 
        h := (*NlMsghdr)(unsafe.Pointer(&buf[0]))
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        if int(h.Len) < NLMSG_HDRLEN || int(h.Len) > len(buf) {
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                return nil, nil, 0, EINVAL
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        }
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        return h, buf[NLMSG_HDRLEN:], nlmAlignOf(int(h.Len)), nil
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}
174 
 
175 
// NetlinkRouteAttr represents the netlink route attribute.
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type NetlinkRouteAttr struct {
177 
        Attr  RtAttr
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        Value []byte
179 
}
180 
 
181 
// ParseNetlinkRouteAttr parses msg's payload as netlink route
182 
// attributes and returns the slice containing the NetlinkRouteAttr
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// structs.
184 
func ParseNetlinkRouteAttr(msg *NetlinkMessage) ([]NetlinkRouteAttr, error) {
185 
        var (
186 
                buf   []byte
187 
                a     *RtAttr
188 
                alen  int
189 
                vbuf  []byte
190 
                e     error
191 
                attrs []NetlinkRouteAttr
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        )
193 
 
194 
        switch msg.Header.Type {
195 
        case RTM_NEWLINK, RTM_DELLINK:
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                buf = msg.Data[SizeofIfInfomsg:]
197 
        case RTM_NEWADDR, RTM_DELADDR:
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                buf = msg.Data[SizeofIfAddrmsg:]
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        case RTM_NEWROUTE, RTM_DELROUTE:
200 
                buf = msg.Data[SizeofRtMsg:]
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        default:
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                return nil, EINVAL
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        }
204 
 
205 
        for len(buf) >= SizeofRtAttr {
206 
                a, vbuf, alen, e = netlinkRouteAttrAndValue(buf)
207 
                if e != nil {
208 
                        break
209 
                }
210 
                ra := NetlinkRouteAttr{}
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                ra.Attr = *a
212 
                ra.Value = vbuf[:int(a.Len)-SizeofRtAttr]
213 
                attrs = append(attrs, ra)
214 
                buf = buf[alen:]
215 
        }
216 
 
217 
        return attrs, nil
218 
}
219 
 
220 
func netlinkRouteAttrAndValue(buf []byte) (*RtAttr, []byte, int, error) {
221 
        h := (*RtAttr)(unsafe.Pointer(&buf[0]))
222 
        if int(h.Len) < SizeofRtAttr || int(h.Len) > len(buf) {
223 
                return nil, nil, 0, EINVAL
224 
        }
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        return h, buf[SizeofRtAttr:], rtaAlignOf(int(h.Len)), nil
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}

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