AdGuardHome/internal/dhcpd/broadcast_others.go
Eugene Burkov b77ceaaf55 Pull request: 3443 dhcp broadcast
Merge in DNS/adguard-home from 3443-fix-wired-dhcp to master

Updates #3443.

Squashed commit of the following:

commit ec7c3b73e274ba7c05c5856cb2f4ea218ad46870
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Sep 7 18:21:07 2021 +0300

    dhcpd: imp docs & naming

commit d87c646af44d837c81aa032e82aad846bde97bc8
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Sep 7 16:56:36 2021 +0300

    dhcpd: fix build tags & log changes

commit cbd0b3c1aa0efb32aeaa9130111719ab3861e817
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Sep 7 16:26:50 2021 +0300

    dhcpd: revert 3443 & imp broadcasting
2021-09-07 18:33:23 +03:00

51 lines
1.6 KiB
Go

//go:build aix || darwin || dragonfly || linux || netbsd || solaris
// +build aix darwin dragonfly linux netbsd solaris
package dhcpd
import (
"net"
"github.com/AdguardTeam/golibs/log"
"github.com/insomniacslk/dhcp/dhcpv4"
)
// broadcast sends resp to the broadcast address specific for network interface.
func (s *v4Server) broadcast(peer net.Addr, conn net.PacketConn, resp *dhcpv4.DHCPv4) {
respData := resp.ToBytes()
log.Debug("dhcpv4: sending to %s: %s", peer, resp.Summary())
// This write to 0xffffffff reverts some behavior changes made in
// https://github.com/AdguardTeam/AdGuardHome/issues/3289. The DHCP
// server should broadcast the message to 0xffffffff but it's
// inconsistent with the actual mental model of DHCP implementation
// which requires the network interface selection to bind to.
//
// See https://github.com/AdguardTeam/AdGuardHome/issues/3480 and
// https://github.com/AdguardTeam/AdGuardHome/issues/3366.
//
// See also https://github.com/AdguardTeam/AdGuardHome/issues/3539.
if _, err := conn.WriteTo(respData, peer); err != nil {
log.Error("dhcpv4: conn.Write to %s failed: %s", peer, err)
}
// peer is expected to be of type *net.UDPConn as the server4.NewServer
// initializes it.
udpPeer, ok := peer.(*net.UDPAddr)
if !ok {
log.Error("dhcpv4: peer is of unexpected type %T", peer)
return
}
// Broadcast the message one more time using the interface-specific
// broadcast address.
udpPeer.IP = s.conf.broadcastIP
log.Debug("dhcpv4: sending to %s: %s", peer, resp.Summary())
if _, err := conn.WriteTo(respData, peer); err != nil {
log.Error("dhcpv4: conn.Write to %s failed: %s", peer, err)
}
}