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| -rw-r--r-- | src/bin/dhcp6/dhcp4o6.dox | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/src/bin/dhcp6/dhcp4o6.dox b/src/bin/dhcp6/dhcp4o6.dox new file mode 100644 index 0000000..61a79c0 --- /dev/null +++ b/src/bin/dhcp6/dhcp4o6.dox @@ -0,0 +1,53 @@ +// Copyright (C) 2016 Internet Systems Consortium, Inc. ("ISC") +// +// This Source Code Form is subject to the terms of the Mozilla Public +// License, v. 2.0. If a copy of the MPL was not distributed with this +// file, You can obtain one at http://mozilla.org/MPL/2.0/. + +/** + @page dhcpv4o6Dhcp6 DHCPv4-over-DHCPv6 DHCPv6 Server Side + +Kea supports DHCPv4-over-DHCPv6 using cooperating DHCPv6 and DHCPv4 +servers. This section describes the DHCPv6 server side. For its +DHCPv6 counter-part, see @ref dhcpv4o6Dhcp4. + +@section dhcp6to4Ipc DHCPv6-to-DHCPv4 Inter Process Communication + +The @c Dhcp6to4Ipc class is derived from the base @c Dhcp4o6IpcBase as +a singleton class (by the static @ref isc::dhcp::Dhcp6to4Ipc::instance +function). @ref isc::dhcp::Dhcp6to4Ipc::open is called to open IPC +UDP sockets and to register @ref isc::dhcp::Dhcp6to4Ipc::handler on +external sockets on the @c IfaceMgr. + +@section dhcp6to4Process DHCPv6-to-DHCPv4 Packet Processing + +Following the DHCPv4-over-DHCPv6 packet flow: + +- a DHCPv6 DHCPv4-QUERY is received from a DHCPv4-over-DHCPv6 client + (standard incoming DHCPv6 message processing is done until + the message type specific part) + +- the isc::dhcp::Dhcpv6Srv::processDhcp4Query method which verifies + a DHCPv4 message option is present and calls the (inherited) @ref + isc::dhcp::Dhcp4o6IpcBase::send method to transmit the DHCPv4-QUERY + with the interface name and remote IPv6 address to the DHCPv4 server + +- the DHCPv4 server processes the DHCPv4-QUERY and returns a + DHCPv4-RESPONSE using the IPC + +- the interface manager (@c IfaceMgr) using the external socket + mechanism invokes @ref isc::dhcp::Dhcp6to4Ipc::handler + +- @ref isc::dhcp::Dhcp6to4Ipc::handler receives the packet by + (inherited) @ref isc::dhcp::Dhcp4o6IpcBase::receive which + decodes and strips the ISC Vendor option. From this point + the code mimics the sending part of standard DHCPv6 packet + processing. + +- the callouts registered for "buffer6_send" hook point are called + (@ref dhcpv6HooksBuffer6Send). Note the "pkt6_send" hook is not used + because the matching query packet is not available + +- the DHCPv6 DHCPv4-RESPONSE packet is sent back to the IPv6 remote address + +*/ |