diff options
| -rw-r--r-- | dhcpv6/client.go | 55 | ||||
| -rw-r--r-- | dhcpv6/types.go | 2 |
2 files changed, 48 insertions, 9 deletions
diff --git a/dhcpv6/client.go b/dhcpv6/client.go index ec1e09d..f46854c 100644 --- a/dhcpv6/client.go +++ b/dhcpv6/client.go @@ -59,10 +59,22 @@ func (c *Client) Exchange(ifname string, solicit DHCPv6) ([]DHCPv6, error) { return conversation, nil } -func (c *Client) sendReceive(ifname string, packet DHCPv6) (DHCPv6, error) { +func (c *Client) sendReceive(ifname string, packet DHCPv6, expectedType MessageType) (DHCPv6, error) { if packet == nil { return nil, fmt.Errorf("Packet to send cannot be nil") } + if expectedType == MSGTYPE_NONE { + // infer the expected type from the packet being sent + if packet.Type() == SOLICIT { + expectedType = ADVERTISE + } else if packet.Type() == REQUEST { + expectedType = REPLY + } else if packet.Type() == RELAY_FORW { + expectedType = RELAY_REPL + } else if packet.Type() == LEASEQUERY { + expectedType = LEASEQUERY_REPLY + } // and probably more + } // if no LocalAddr is specified, get the interface's link-local address var laddr net.UDPAddr if c.LocalAddr == nil { @@ -109,13 +121,38 @@ func (c *Client) sendReceive(ifname string, packet DHCPv6) (DHCPv6, error) { buf := make([]byte, maxUDPReceivedPacketSize) oobdata := []byte{} // ignoring oob data conn.SetReadDeadline(time.Now().Add(c.ReadTimeout)) - n, _, _, _, err := conn.ReadMsgUDP(buf, oobdata) - if err != nil { - return nil, err + var ( + adv DHCPv6 + isMessage bool + ) + msg, ok := packet.(*DHCPv6Message) + if ok { + isMessage = true } - adv, err := FromBytes(buf[:n]) - if err != nil { - return nil, err + for { + n, _, _, _, err := conn.ReadMsgUDP(buf, oobdata) + if err != nil { + return nil, err + } + adv, err = FromBytes(buf[:n]) + if err != nil { + return nil, err + } + if recvMsg, ok := adv.(*DHCPv6Message); ok && isMessage { + // if a regular message, check the transaction ID first + // XXX should this unpack relay messages and check the XID of the + // inner packet too? + if msg.TransactionID() != recvMsg.TransactionID() { + // different XID, we don't want this packet for sure + continue + } + } + if expectedType == MSGTYPE_NONE { + // just take whatever arrived + break + } else if adv.Type() == expectedType { + break + } } return adv, nil } @@ -130,7 +167,7 @@ func (c *Client) Solicit(ifname string, solicit DHCPv6) (DHCPv6, DHCPv6, error) return nil, nil, err } } - advertise, err := c.sendReceive(ifname, solicit) + advertise, err := c.sendReceive(ifname, solicit, MSGTYPE_NONE) return solicit, advertise, err } @@ -144,6 +181,6 @@ func (c *Client) Request(ifname string, advertise, request DHCPv6) (DHCPv6, DHCP return nil, nil, err } } - reply, err := c.sendReceive(ifname, request) + reply, err := c.sendReceive(ifname, request, MSGTYPE_NONE) return request, reply, err } diff --git a/dhcpv6/types.go b/dhcpv6/types.go index bbe4c5b..795a284 100644 --- a/dhcpv6/types.go +++ b/dhcpv6/types.go @@ -5,6 +5,8 @@ package dhcpv6 type MessageType uint8 const ( + // MSGTYPE_NONE is used internally and is not part of the RFC + MSGTYPE_NONE MessageType = 0 SOLICIT MessageType = 1 ADVERTISE MessageType = 2 REQUEST MessageType = 3 |