diff options
Diffstat (limited to 'dhcpv4/client.go')
| -rw-r--r-- | dhcpv4/client.go | 50 |
1 files changed, 35 insertions, 15 deletions
diff --git a/dhcpv4/client.go b/dhcpv4/client.go index fbdc280..1ce6a5c 100644 --- a/dhcpv4/client.go +++ b/dhcpv4/client.go @@ -148,7 +148,7 @@ func (c *Client) Exchange(ifname string, discover *DHCPv4) ([]DHCPv4, error) { conversation[0] = *discover // Offer - offer, err := BroadcastSendReceive(sfd, rfd, discover, c.ReadTimeout, c.WriteTimeout) + offer, err := BroadcastSendReceive(sfd, rfd, discover, c.ReadTimeout, c.WriteTimeout, MessageTypeOffer) if err != nil { return conversation, err } @@ -162,7 +162,7 @@ func (c *Client) Exchange(ifname string, discover *DHCPv4) ([]DHCPv4, error) { conversation = append(conversation, *request) // Ack - ack, err := BroadcastSendReceive(sfd, rfd, discover, c.ReadTimeout, c.WriteTimeout) + ack, err := BroadcastSendReceive(sfd, rfd, request, c.ReadTimeout, c.WriteTimeout, MessageTypeAck) if err != nil { return conversation, err } @@ -171,8 +171,9 @@ func (c *Client) Exchange(ifname string, discover *DHCPv4) ([]DHCPv4, error) { } // BroadcastSendReceive broadcasts packet (with some write timeout) and waits for a -// response up to some read timeout value. -func BroadcastSendReceive(sendFd, recvFd int, packet *DHCPv4, readTimeout, writeTimeout time.Duration) (*DHCPv4, error) { +// response up to some read timeout value. If the message type is not +// MessageTypeNone, it will wait for a specific message type +func BroadcastSendReceive(sendFd, recvFd int, packet *DHCPv4, readTimeout, writeTimeout time.Duration, messageType MessageType) (*DHCPv4, error) { packetBytes, err := MakeRawBroadcastPacket(packet.ToBytes()) if err != nil { return nil, err @@ -194,17 +195,36 @@ func BroadcastSendReceive(sendFd, recvFd int, packet *DHCPv4, readTimeout, write defer conn.Close() conn.SetReadDeadline(time.Now().Add(readTimeout)) - buf := make([]byte, MaxUDPReceivedPacketSize) - n, _, _, _, err := conn.(*net.UDPConn).ReadMsgUDP(buf, []byte{}) - if err != nil { - errs <- err - return - } - - response, err = FromBytes(buf[:n]) - if err != nil { - errs <- err - return + for { + buf := make([]byte, MaxUDPReceivedPacketSize) + n, _, _, _, err := conn.(*net.UDPConn).ReadMsgUDP(buf, []byte{}) + if err != nil { + errs <- err + return + } + + response, err = FromBytes(buf[:n]) + if err != nil { + errs <- err + return + } + // check that this is a response to our message + if response.TransactionID() != packet.TransactionID() { + continue + } + // wait for a response message + if response.Opcode() != OpcodeBootReply { + continue + } + // if we are not requested to wait for a specific message type, + // return what we have + if messageType == MessageTypeNone { + break + } + // break if it's a reply of the desired type, continue otherwise + if response.MessageType() != nil && *response.MessageType() == messageType { + break + } } recvErrors <- nil }(recvErrors) |