Refactor client code, add timeout capabilities

1 files changed, 17 insertions, 75 deletions

diff --git a/dhcpv4/bsdp/client.go b/dhcpv4/bsdp/client.go
index d2e9c5c..00e5ad5 100644
--- a/dhcpv4/bsdp/client.go
+++ b/dhcpv4/bsdp/client.go
@@ -3,22 +3,23 @@
 package bsdp
 
 import (
-	"fmt"
-	"net"
-	"syscall"
+	"errors"
 
 	"github.com/insomniacslk/dhcp/dhcpv4"
 )
 
-// Client is a BSDP-specific client suitable for performing BSDP exchanges.
-type Client dhcpv4.Client
-
 // Exchange runs a full BSDP exchange (Inform[list], Ack, Inform[select],
 // Ack). Returns a list of DHCPv4 structures representing the exchange.
-func (c *Client) Exchange(ifname string, informList *dhcpv4.DHCPv4) ([]dhcpv4.DHCPv4, error) {
+func Exchange(client *dhcpv4.Client, ifname string, informList *dhcpv4.DHCPv4) ([]dhcpv4.DHCPv4, error) {
 	conversation := make([]dhcpv4.DHCPv4, 1)
 	var err error
 
+	// Get our file descriptor for the broadcast socket.
+	fd, err := dhcpv4.MakeBroadcastSocket(ifname)
+	if err != nil {
+		return conversation, err
+	}
+
 	// INFORM[LIST]
 	if informList == nil {
 		informList, err = NewInformListForInterface(ifname, dhcpv4.ClientPort)
@@ -28,92 +29,33 @@ func (c *Client) Exchange(ifname string, informList *dhcpv4.DHCPv4) ([]dhcpv4.DH
 	}
 	conversation[0] = *informList
 
-	// TODO: deduplicate with code in dhcpv4/client.go
-	fd, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_RAW, syscall.IPPROTO_RAW)
-	if err != nil {
-		return conversation, err
-	}
-	err = syscall.SetsockoptInt(fd, syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1)
-	if err != nil {
-		return conversation, err
-	}
-	err = syscall.SetsockoptInt(fd, syscall.IPPROTO_IP, syscall.IP_HDRINCL, 1)
-	if err != nil {
-		return conversation, err
-	}
-	err = syscall.SetsockoptInt(fd, syscall.SOL_SOCKET, syscall.SO_BROADCAST, 1)
-	if err != nil {
-		return conversation, err
-	}
-	err = dhcpv4.BindToInterface(fd, ifname)
+	// ACK[LIST]
+	ackForList, err := dhcpv4.SendReceive(client, fd, informList)
 	if err != nil {
 		return conversation, err
 	}
-
-	bcast := [4]byte{}
-	copy(bcast[:], net.IPv4bcast)
-	daddr := syscall.SockaddrInet4{Port: dhcpv4.ClientPort, Addr: bcast}
-	packet, err := dhcpv4.MakeRawBroadcastPacket(informList.ToBytes())
-	if err != nil {
-		return conversation, err
-	}
-	err = syscall.Sendto(fd, packet, 0, &daddr)
-	if err != nil {
-		return conversation, err
-	}
-
-	// ACK 1
-	conn, err := net.ListenUDP("udp4", &net.UDPAddr{IP: net.IPv4zero, Port: dhcpv4.ClientPort})
-	if err != nil {
-		return conversation, err
-	}
-	defer conn.Close()
-
-	buf := make([]byte, dhcpv4.MaxUDPReceivedPacketSize)
-	oobdata := []byte{} // ignoring oob data
-	n, _, _, _, err := conn.ReadMsgUDP(buf, oobdata)
-	ack1, err := dhcpv4.FromBytes(buf[:n])
-	if err != nil {
-		return conversation, err
-	}
-	// TODO match the packet content
-	// TODO check that the peer address matches the declared server IP and port
-	conversation = append(conversation, *ack1)
+	conversation = append(conversation, *ackForList)
 
 	// Parse boot images sent back by server
-	bootImages, err := ParseBootImageListFromAck(*ack1)
+	bootImages, err := ParseBootImageListFromAck(*ackForList)
 	if err != nil {
 		return conversation, err
 	}
 	if len(bootImages) == 0 {
-		return conversation, fmt.Errorf("Got no BootImages from server")
+		return conversation, errors.New("got no BootImages from server")
 	}
 
 	// INFORM[SELECT]
-	informSelect, err := InformSelectForAck(*ack1, dhcpv4.ClientPort, bootImages[0])
+	informSelect, err := InformSelectForAck(*ackForList, dhcpv4.ClientPort, bootImages[0])
 	if err != nil {
 		return conversation, err
 	}
 	conversation = append(conversation, *informSelect)
-	packet, err = dhcpv4.MakeRawBroadcastPacket(informSelect.ToBytes())
-	if err != nil {
-		return conversation, err
-	}
-	err = syscall.Sendto(fd, packet, 0, &daddr)
-	if err != nil {
-		return conversation, err
-	}
 
-	// ACK 2
-	buf = make([]byte, dhcpv4.MaxUDPReceivedPacketSize)
-	n, _, _, _, err = conn.ReadMsgUDP(buf, oobdata)
-	ack2, err := dhcpv4.FromBytes(buf[:n])
+	// ACK[SELECT]
+	ackForSelect, err := dhcpv4.SendReceive(client, fd, informSelect)
 	if err != nil {
 		return conversation, err
 	}
-	// TODO match the packet content
-	// TODO check that the peer address matches the declared server IP and port
-	conversation = append(conversation, *ack2)
-
-	return conversation, nil
+	return append(conversation, *ackForSelect), nil
 }