fix: add dhcp discover packet to linux swiftv2 to ensure mappings exist for dns (#2989)

* add dhcp client

* address linter issues

* issue dhcp discover request without libraries

* remove library references

* add build tag and remove rand dependency

* address linter issues

* update logging

* fix logging

* move unix sockets to interface to address feedback

* address linter issues

* prevent leaking sockets on error

* remove reuse address option

* add comments

* make dhcp client

Author: QxBytes

cni/network/network.go

@@ -21,6 +21,7 @@ import (
 	"github.com/Azure/azure-container-networking/cns"
 	cnscli "github.com/Azure/azure-container-networking/cns/client"
 	"github.com/Azure/azure-container-networking/common"
+	"github.com/Azure/azure-container-networking/dhcp"
 	"github.com/Azure/azure-container-networking/iptables"
 	"github.com/Azure/azure-container-networking/netio"
 	"github.com/Azure/azure-container-networking/netlink"
@@ -130,7 +131,7 @@ func NewPlugin(name string,
 
 	nl := netlink.NewNetlink()
 	// Setup network manager.
-	nm, err := network.NewNetworkManager(nl, platform.NewExecClient(logger), &netio.NetIO{}, network.NewNamespaceClient(), iptables.NewClient())
+	nm, err := network.NewNetworkManager(nl, platform.NewExecClient(logger), &netio.NetIO{}, network.NewNamespaceClient(), iptables.NewClient(), dhcp.New(logger))
 	if err != nil {
 		return nil, err
 	}