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.
This patch add support to enables to send User Class option code 77
RFC 3004.
This option MAY carry multiple User Classes.
The format of this option is as follows:
Code Len Value
+-----+-----+--------------------- . . . --+
| 77 | N | User Class Data ('Len' octets) |
+-----+-----+--------------------- . . . --+
where Value consists of one or more instances of User Class Data.
Each instance of User Class Data is formatted as follows:
UC_Len_i User_Class_Data_i
+--------+------------------------ . . . --+
| L_i | Opaque-Data ('UC_Len_i' octets) |
+--------+------------------------ . . . --+
UserClass=
A DHCPv4 client can use UserClass option to identify the type or category of user or applications
it represents. The information contained in this option is an string that represents the user class
of which the client is a member. Each class sets an identifying string of information to be used by the DHCP service to classify clients. Takes a whitespace-separated list.
UserClass= hello world how are you
Closes: RFC: #5134
This makes users can configure DHCPv4 client with ClientIdentifier=duid-only.
If set so, then DHCP client sends only DUID as the client identifier.
This may not be RFC compliant, but some setups require this.
Closes#7828.
This adds a modified version of dhcp6_option_parse_domainname() that is
able to parse compressed domain names, borrowing the idea from
dns_packet_read_name(). It also adds pieces in networkd-link and
networkd-manager to properly save/load the added option field.
Resolves#2710.
A field "index" is not particularly precise and also might conflict with libc's
index() function definition. Also, pretty much everywhere else we call this
concept "ifindex", including in networkd, the primary user of these libraries.
Hence, let's fix this up and call this "ifindex" everywhere here too.
libsystemd-network provides the public function
sd_dhcp_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 dhcp-protocol.h. Move the enum definition to the
public header sd-dhcp-client.h and properly namespace values.
GLIB has recently started to officially support the gcc cleanup
attribute in its public API, hence let's do the same for our APIs.
With this patch we'll define an xyz_unrefp() call for each public
xyz_unref() call, to make it easy to use inside a
__attribute__((cleanup())) expression. Then, all code is ported over to
make use of this.
The new calls are also documented in the man pages, with examples how to
use them (well, I only added docs where the _unref() call itself already
had docs, and the examples, only cover sd_bus_unrefp() and
sd_event_unrefp()).
This also renames sd_lldp_free() to sd_lldp_unref(), since that's how we
tend to call our destructors these days.
Note that this defines no public macro that wraps gcc's attribute and
makes it easier to use. While I think it's our duty in the library to
make our stuff easy to use, I figure it's not our duty to make gcc's own
features easy to use on its own. Most likely, client code which wants to
make use of this should define its own:
#define _cleanup_(function) __attribute__((cleanup(function)))
Or similar, to make the gcc feature easier to use.
Making this logic public has the benefit that we can remove three header
files whose only purpose was to define these functions internally.
See #2008.
Exported header files should not include internal headers. Fix that.
Exported header files should not use the bool type. So far we opted to
stick to C89 for exported headers, and hence use "int" for bools in
them. Continue to do so.
Exported header files should have #include lines for everything they use
including inttypes.h and sys/types.h, so that they may be included in
any order.
Exported header files should have C++ guards, hence add them.
Exported header files should not use gcc extensions like #pragma once,
get rid of it.
The client identifier can be in many different formats, not just
the one that systemd creates from the Ethernet MAC address. Non-
ethernet interfaces may have different client IDs formats. Users
may also have custom client IDs that the wish to use to preserve
lease options delivered by servers configured with the existing
client ID.
Like Infiniband. See RFC 4390 section 2.1 for details on DHCP
and Infiniband; chaddr is zeroed, hlen is set to 0, and htype
is set to ARPHRD_INFINIBAND because IB hardware addresses
are 20 bytes in length.
It appears there is no good way to decide whether or not broadcasts should be enabled,
there is hardware that must have broadcast, and there are networks that only allow
unicast. So we give up and make this configurable.
By default, unicast is used, but if the kernel were to inform us abotu certain
interfaces requiring broadcast, we could change this to opt-in by default in
those cases.
Vendor Class Identifier be used by DHCP clients to identify
their vendor type and configuration. When using this option,
vendors can define their own specific identifier values, such
as to convey a particular hardware or operating system
configuration or other identifying information.
Vendor-specified DHCP options—features that let administrators assign
separate options to clients with similar configuration requirements.
For example, if DHCP-aware clients for example we want to separate
different gateway and option for different set of people
(dev/test/hr/finance) in a org or devices for example web/database
servers or let's say in a embedded device etc and require a different
default gateway or DNS server than the rest of clients.
Send hostname (option 12) in DISCOVER and REQUEST messages so the
DHCP server could use it to register with dynamic DNS and such.
To opt-out of this behaviour set SendHostname to false in [DHCP]
section of .network file
[tomegun: rebased, made sure a failing set_hostname is a noop and moved
config from DHCPv4 to DHCP]
The DHCP library user can decide to free the DHCP client any time
the callback is called. After the callback has been called, other
computations may still be needed - the best example being a full
restart of the DHCP procedure in case of lease expiry.
Fix this by introducing proper reference counting. Properly handle
a returned NULL from the notify and stop functions if the DHCP
client was freed.
This allows us users of the library to keep copies of old leases. This is
used by networkd to know what addresses to drop (if any) when the lease
expires.
In the future this may be used by DNAv4 and sd-dhcp-server.
Make them more simiar to sd_bus and friends. Also factor out the event attachment. In the future,
we will likely want to support external main-loops, so this is a first step. For the time being,
we are still requiring an sd_event to be attached though.
Process a DHCP Ack/Nak in much the same way as an DHCP Offer. Factor
out header verification and process options sent. Add notification
functionality with discrete values for the outcome of the DHCP Ack/
Nak processing.
Require a main loop to be set when creating a DHCP client. Set up
a timer to resend DHCP Discover messages and add a 0-2 second
delay to the timeout value. Move to state Selecting after successful
sending of a Discover message.
On starting the client, use the supplied interface mac address and create
a transaction id. Puzzle together an IP/UDP/DHCP Discover message, compute
checksums and send it out as a raw packet.
Create an additional function that constructs default options common to
all DHCP messages.
Set the DHCP Client ID option as noticed by Grant Erickson in ConnMan
commit b18d9798b3a0ae46ed87d6d2be8d5a474bf3ab1e:
"Some Internet gateways and Wi-Fi access points are unhappy when the
DHCPv4 client-id option (61) is missing and will refuse to issue a
DHCP lease."
Provide functionality for initializing a DHCP client struct, setting
interface index, last used address and additional options to request.
On initialization the most useful options are added by default.
