This part of the copyright blurb stems from the GPL use recommendations:
https://www.gnu.org/licenses/gpl-howto.en.html
The concept appears to originate in times where version control was per
file, instead of per tree, and was a way to glue the files together.
Ultimately, we nowadays don't live in that world anymore, and this
information is entirely useless anyway, as people are very welcome to
copy these files into any projects they like, and they shouldn't have to
change bits that are part of our copyright header for that.
hence, let's just get rid of this old cruft, and shorten our codebase a
bit.
Files which are installed as-is (any .service and other unit files, .conf
files, .policy files, etc), are left as is. My assumption is that SPDX
identifiers are not yet that well known, so it's better to retain the
extended header to avoid any doubt.
I also kept any copyright lines. We can probably remove them, but it'd nice to
obtain explicit acks from all involved authors before doing that.
Sanitize code for parsing DHCPv6 IA NA and TA options and their
nested Status options so that the options can be fully and
properly ignored should they not be conformant to the specification.
Do this by defining a proper DHCP6Option structure and sending that
structure to the parsing function. The parsing function will then
not manipulate either any option data pointers or their lengths in
order to iterate over the current option. Needless to say, this
affects a few files including the test program.
Implement DHCPv6 option to exchange information about the Fully
Qualified Domain Name (FQDN) according to RFC 4704.
The RFC 4704 describes two models of operations in section 3,
currently only the second model is supported (DHCPv6 server
updates both the AAAA and the PTR RRs).
The existing DHCP Section Options SendHostname and Hostname are
sent as FQDN to the server. According to section 4.2 sending
only parts of its FQDN is allowed.
Fixes#4682.
libsystemd-network provides the public function
sd_dhcp6_client_set_request_option() to enable the request of a given
DHCP option. However the enum defining such options is defined in the
internal header dhcp6-protocol.h. Move the enum definition to the
public header sd-dhcp6-client.h and properly namespace values.
Although the SNTP option specified in RFC 4075 has been deprecated, some
servers are still sending NTP information with this option. Use the SNTP
information provided only if the NTP option is not present.
Update the test case as SNTP information is also requested.
Implement Information Request message according to RFC 3315, section
18.1.5. with the excepion that the first message is not delayed by a
random amount. Instead systemd-networkd is supposed to take care of
desynchronizing between other clients.
Initialize the DHCPv6 client structure in sd_dhcp6_client_start()
as this allows toggling between information request and normal
DHCPv6 address aquisition modes.
Start sending Renew and Rebind DHCPv6 messages when respective timers T1
and T2 expire. Rebind messages do not include a Server ID option and the
Rebind procedure ends when the last IPv6 address valid lifetime expires,
whereafter the client restarts the address acquisition procedure by
Soliciting for available servers.
See RFC 3315, sections 18.1.3. and 18.1.4. for details.
Provide a function to request more options from the DHCPv6 server.
Provide a sensible default set at startup and add test basic test
cases for the intended usage.
Define DNS and NTP related option codes and add comments for the
unassigned codes.
As described in RFC 3315, Section 17.1.2, a client has to wait until the
first timeout has elapsed before it is allowed to request IPv6 addresses
from the DHCPv6 server. This is indicated by a non-NULL lease and a
non-zero resend count. Should the Advertisement contain a preference
value of 255 or be received after the first timeout, IPv6 address
requesting is started immediately.
In response to these events, create a Request message and set up proper
resend timers to send the message to the server.
When receiving DHCPv6 messages, discard the ones that are not meant
for DHCPv6 clients and verify the transaction id. Once that is done,
process the Advertise message and select the Advertise with the
highest preference.
Create a separate function for lease information parsing so that it
can be reused in other parts of the protocol. Verify both DUID and
IAID in the received message and store other necessary information
with the lease structure.
Add a function that creates a UDP socket bound to the given interface
and optionally to an IPv6 address. Add another function that will
send the DHCPv6 UDP packet to its destination.
Using IPV6_PKTINFO in setsockopt to bind the IPv6 socket to an
interface is documented in section 4. of RFC 3542, "Advanced Sockets
Application Program Interface (API) for IPv6"
Add a define for DHCPv6 Relay Agents and Servers multicast address as
its not available elsewhere.
Add the core of DHCPv6 client message retransmission and upper bound
timer and message count handling according to RFC 3315 Secions 7.1.2
and 14. Omit the DHCPv6 initial delay; for now it is assumed that
systemd-networkd will provide decent startup randomization that will
desynchronize the clients.
When reinitializing the client, clear all timers.
