daxi20/AdGuardHome
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Pull request: 4337 increase msg size

Browse Source 
Merge in DNS/adguard-home from 4337-dhcp-msg-len to master

Updates #4337.

Squashed commit of the following:

commit 55e53c1fadd4ccb2a8b94117afff82e9a5d2734b
Merge: f37070ea da1ae338
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Wed Sep 7 14:14:21 2022 +0300

    Merge branch 'master' into 4337-dhcp-msg-len

commit f37070ea0f3a7ff8efcbbafd36001f78d9b082b5
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Wed Sep 7 13:15:25 2022 +0300

    dhcpd: imp ether pkt building

commit fa43a0bcc24d4ca5e9193899dbba8495f3de5df9
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Tue Sep 6 18:55:07 2022 +0300

    dhcpd: incr msg size
This commit is contained in:
Eugene Burkov
2022-09-07 14:34:30 +03:00
parent da1ae33805
commit 53209bc42c
4 changed files with 50 additions and 31 deletions
Download Patch File Download Diff File Expand all files Collapse all files

24
internal/dhcpd/v4.go
View File

@@ -1086,6 +1086,12 @@ func (s *v4Server) packetHandler(conn net.PacketConn, peer net.Addr, req *dhcpv4
s.send(peer, conn, req, resp)
}
// minDHCPMsgSize is the minimum length of the encoded DHCP message in bytes
// according to RFC-2131.
//
// See https://datatracker.ietf.org/doc/html/rfc2131#section-2.
const minDHCPMsgSize = 576
// send writes resp for peer to conn considering the req's parameters according
// to RFC-2131.
//
@@ -1126,8 +1132,22 @@ func (s *v4Server) send(peer net.Addr, conn net.PacketConn, req, resp *dhcpv4.DH
// Go on since peer is already set to broadcast.
}
log.Debug("dhcpv4: sending to %s: %s", peer, resp.Summary())
if _, err := conn.WriteTo(resp.ToBytes(), peer); err != nil {
pktData := resp.ToBytes()
pktLen := len(pktData)
if pktLen < minDHCPMsgSize {
// Expand the packet to match the minimum DHCP message length. Although
// the dhpcv4 package deals with the BOOTP's lower packet length
// constraint, it seems some clients expecting the length being at least
// 576 bytes as per RFC 2131 (and an obsolete RFC 1533).
//
// See https://github.com/AdguardTeam/AdGuardHome/issues/4337.
pktData = append(pktData, make([]byte, minDHCPMsgSize-pktLen)...)
}
log.Debug("dhcpv4: sending %d bytes to %s: %s", len(pktData), peer, resp.Summary())
_, err := conn.WriteTo(pktData, peer)
if err != nil {
log.Error("dhcpv4: conn.Write to %s failed: %s", peer, err)
}
}