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// +build darwin
package dhcpv4
import (
"fmt"
"net"
"syscall"
)
// BSDPExchange runs a full BSDP exchange (Inform[list], Ack, Inform[select],
// Ack). Returns a list of DHCPv4 structures representing the exchange.
func (c *Client) BSDPExchange(ifname string, d *DHCPv4) ([]DHCPv4, error) {
conversation := make([]DHCPv4, 1)
var err error
// INFORM[LIST]
if d == nil {
d, err = NewInformListForInterface(ifname, ClientPort)
}
conversation[0] = *d
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 = BindToInterface(fd, ifname)
if err != nil {
return conversation, err
}
daddr := syscall.SockaddrInet4{Port: ClientPort, Addr: [4]byte{255, 255, 255, 255}}
packet, err := makeRawBroadcastPacket(d.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.IPv4(0, 0, 0, 0), Port: ClientPort})
if err != nil {
return conversation, err
}
defer conn.Close()
buf := make([]byte, maxUDPReceivedPacketSize)
oobdata := []byte{} // ignoring oob data
n, _, _, _, err := conn.ReadMsgUDP(buf, oobdata)
ack1, err := 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)
// Parse boot images sent back by server
bootImages, err := ParseBootImageListFromAck(*ack1)
fmt.Println(bootImages)
if err != nil {
return conversation, err
}
if len(bootImages) == 0 {
return conversation, fmt.Errorf("Got no BootImages from server")
}
// INFORM[SELECT]
request, err := InformSelectForAck(*ack1, ClientPort, bootImages[0])
if err != nil {
return conversation, err
}
conversation = append(conversation, *request)
packet, err = makeRawBroadcastPacket(request.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, maxUDPReceivedPacketSize)
n, _, _, _, err = conn.ReadMsgUDP(buf, oobdata)
acknowledge, err := 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, *acknowledge)
return conversation, nil
}
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