RFC: 8415
21.17. Vendor-specific Information Option
This option is used by clients and servers to exchange vendor-
specific information.
The format of the Vendor-specific Information option is:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_VENDOR_OPTS | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| enterprise-number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. vendor-option-data .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 30: Vendor-specific Information Option Format
option-code OPTION_VENDOR_OPTS (17).
option-len 4 + length of vendor-option-data field.
enterprise-number The vendor's registered Enterprise Number as
maintained by IANA [IANA-PEN]. A 4-octet
field containing an unsigned integer.
vendor-option-data Vendor options, interpreted by
vendor-specific code on the clients and
servers. A variable-length field (4 octets
less than the value in the option-len field).
The definition of the information carried in this option is vendor
specific. The vendor is indicated in the enterprise-number field.
Use of vendor-specific information allows enhanced operation,
utilizing additional features in a vendor's DHCP implementation. A
DHCP client that does not receive requested vendor-specific
information will still configure the node's IPv6 stack to be
functional.
The vendor-option-data field MUST be encoded as a sequence of
code/length/value fields of format identical to the DHCP options (see
Section 21.1). The sub-option codes are defined by the vendor
identified in the enterprise-number field and are not managed by
IANA. Each of the sub-options is formatted as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sub-opt-code | sub-option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. sub-option-data .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 31: Vendor-specific Options Format
sub-opt-code The code for the sub-option. A 2-octet
field.
sub-option-len An unsigned integer giving the length of the
sub-option-data field in this sub-option in
octets. A 2-octet field.
sub-option-data The data area for the sub-option. The
length, in octets, is specified by
sub-option-len.
Multiple instances of the Vendor-specific Information option may
appear in a DHCP message. Each instance of the option is interpreted
according to the option codes defined by the vendor identified by the
Enterprise Number in that option. Servers and clients MUST NOT send
more than one instance of the Vendor-specific Information option with
the same Enterprise Number. Each instance of the Vendor-specific
Information option MAY contain multiple sub-options.
A client that is interested in receiving a Vendor-specific
Information option:
- MUST specify the Vendor-specific Information option in an Option
Request option.
- MAY specify an associated Vendor Class option (see Section 21.16).
- MAY specify the Vendor-specific Information option with
appropriate data.
Servers only return the Vendor-specific Information options if
specified in Option Request options from clients and:
- MAY use the Enterprise Numbers in the associated Vendor Class
options to restrict the set of Enterprise Numbers in the
Vendor-specific Information options returned.
- MAY return all configured Vendor-specific Information options.
- MAY use other information in the packet or in its configuration to
determine which set of Enterprise Numbers in the Vendor-specific
Information options to return.
We need to fix RCC 2215 behaviour with rfc7550 errata
and https://tools.ietf.org/html/rfc8415.
[RFC3315] specifies that a client must ignore an Advertise message if
a server will not assign any addresses to a client, and [RFC3633]
specifies that a client must ignore an Advertise message if a server
returns the NoPrefixAvail status to a requesting router. Thus, a
client requesting both IA_NA and IA_PD, with a server that only
offers either addresses or delegated prefixes, is not supported by
the current protocol specifications.
Solution: a client SHOULD accept Advertise messages, even when not
all IA option types are being offered. And, in this case, the client
SHOULD include the not offered IA option types in its Request. A
client SHOULD only ignore an Advertise message when none of the
requested IA options include offered addresses or delegated prefixes.
Note that ignored messages MUST still be processed for SOL_MAX_RT and
INF_MAX_RT options as specified in [RFC7083].
Replace Section 17.1.3 of RFC 3315: (existing errata)
The client MUST ignore any Advertise message that includes a Status
Code option containing the value NoAddrsAvail, with the exception
that the client MAY display the associated status message(s) to the
user.
With the following text (which addresses the existing erratum
[Err2471] and includes the changes made by [RFC7083]):
The client MUST ignore any Advertise message that contains no
addresses (IAADDR options encapsulated in IA_NA or IA_TA options)
and no delegated prefixes (IAPREFIX options encapsulated in IA_PD
options; see RFC 3633) with the exception that the client:
- MUST process an included SOL_MAX_RT option (RFC 7083) and
- MUST process an included INF_MAX_RT option (RFC 7083).
A client can display any associated status message(s) to the user
or activity log.
The client ignoring this Advertise message MUST NOT restart the
Solicit retransmission timer.
```
21.16. Vendor Class Option
This option is used by a client to identify the vendor that
manufactured the hardware on which the client is running. The
information contained in the data area of this option is contained in
one or more opaque fields that identify details of the hardware
configuration. The format of the Vendor Class option is:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_VENDOR_CLASS | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| enterprise-number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. vendor-class-data .
. . . . .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 28: Vendor Class Option Format
option-code OPTION_VENDOR_CLASS (16).
option-len 4 + length of vendor-class-data field.
enterprise-number The vendor's registered Enterprise Number as
maintained by IANA [IANA-PEN]. A 4-octet
field containing an unsigned integer.
vendor-class-data The hardware configuration of the node on
which the client is running. A
variable-length field (4 octets less than the
value in the option-len field).
The vendor-class-data field is composed of a series of separate
items, each of which describes some characteristic of the client's
hardware configuration. Examples of vendor-class-data instances
might include the version of the operating system the client is
running or the amount of memory installed on the client.
Each instance of vendor-class-data is formatted as follows:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...-+-+-+-+-+-+-+
| vendor-class-len | opaque-data |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...-+-+-+-+-+-+-+
Figure 29: Format of vendor-class-data Field
The vendor-class-len field is 2 octets long and specifies the length
of the opaque vendor-class-data in network byte order.
Servers and clients MUST NOT include more than one instance of
OPTION_VENDOR_CLASS with the same Enterprise Number. Each instance
of OPTION_VENDOR_CLASS can carry multiple vendor-class-data
instances.
```
sd-network: DHCPv6 - add support to send userclass option
21.15. User Class Option
The User Class option is used by a client to identify the type or
category of users or applications it represents.
The format of the User Class option is:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_USER_CLASS | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. user-class-data .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 26: User Class Option Format
option-code OPTION_USER_CLASS (15).
option-len Length of user-class-data field.
user-class-data The user classes carried by the client. The
length, in octets, is specified by
option-len.
The information contained in the data area of this option is
contained in one or more opaque fields that represent the user class
or classes of which the client is a member. A server selects
configuration information for the client based on the classes
identified in this option. For example, the User Class option can be
used to configure all clients of people in the accounting department
with a different printer than clients of people in the marketing
department. The user class information carried in this option MUST
be configurable on the client.
The data area of the User Class option MUST contain one or more
instances of user-class-data information. Each instance of
user-class-data is formatted as follows:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...-+-+-+-+-+-+-+
| user-class-len | opaque-data |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...-+-+-+-+-+-+-+
Figure 27: Format of user-class-data Field
Since we now have the possibility to request prefixes to be delegated
without corresponding IPv6 addresses, it does not make sense to store
lease T1 and T2 timeouts in the otherwise unused IA_NA structure.
Therefore lease timeouts T1 and T2 are moved to the DHCPv6 client
structure, as there will be only one set of stateful timeouts required
by RFC 7550, Section 4.3.
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.
Parse IA PD options and the prefixes in one or more PD Prefix
options. As the PD option contains identical data as the IA NA
option, re-use the same general data structures and sub-option
parsing logic. Similar to IA NA addresses, PD and associated
prefixes are stored in the address list of the IA PD lease.
An IA sub-option Status code will affect the IA NA and IA PD
option in question and cause those options to be ignored. A
Status code option in an IA Address or IA PD Prefix option
affects only that IA Address or Prefix.
Factor out IA Address option parsing and fix it so that all conditions
are checked before a new address is allocated and added to the address
list. Note also that the IA Address option can contain a nested Status
option. If the status in anything else than zero, the DHCPv6 server is
communicating an error condition and the address cannot be used.
Status option nesting is clarified in RFC 7550, Section 4.1.
The IA Address option is included as a typedef so that the lifetimes
can be inspected before allocating a new address and the option length
needed is easily available.
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.
There are more than enough calls doing string manipulations to deserve
its own files, hence do something about it.
This patch also sorts the #include blocks of all files that needed to be
updated, according to the sorting suggestions from CODING_STYLE. Since
pretty much every file needs our string manipulation functions this
effectively means that most files have sorted #include blocks now.
Also touches a few unrelated include files.
Add a helper function containing a modified version of dns_packet_read_name()
that does not use DnsPacket to extract a string array of domain names from
the provided option data. The domain names are stored uncompressed as defined
in Section 8. of RFC 3315.
- Rename log_meta() → log_internal(), to follow naming scheme of most
other log functions that are usually invoked through macros, but never
directly.
- Rename log_info_object() to log_object_info(), simply because the
object should be before any other parameters, to follow OO-style
programming style.
This change has two benefits:
- The format string %m will now resolve to the specified error (or to
errno if the specified error is 0. This allows getting rid of a ton of
strerror() invocations, a function that is not thread-safe.
- The specified error can be passed to the journal in the ERRNO= field.
Now of course, we just need somebody to convert all cases of this:
log_error("Something happened: %s", strerror(-r));
into thus:
log_error_errno(-r, "Something happened: %m");
With this change the DHCP6_OPTION_IAADDR_LEN define can be removed in
favor of using sizeof(). Using the name of the struct and sizeof()
makes it clearer how much and what data is being copied from the
DHCPv6 message.
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 functionality to parse DHCPv6 Identity Association for
Non-temporary (IA_NA) and Temporary Addresses (IA_TA) options.
Both of them contain one or more IA Address (IAADDR) options
and optinally a status code option. Only the IA_NA option
contains lease lifetimes. See RFC 3315, sections 22.4., 22.5.,
22.6., 22.13. and appendix B. for details. If the lease
timeouts are not set, use the ones recommended for servers in
section 22.4.
Factor out common code in the form of an option header parsing
helper function.
Implement the initial functionality used for creating a DHCPv6 Solicit
message containing the needed options and send it to the DHCPv6
broadcast address. Increase the sent message count and ensure that
the Solicit Initial Retransmission Time is strictly greater than
the Solicitation IRT as described in RFC 3315, section 17.1.2.
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 option appending and parsing. DHCPv6 options are not aligned, thus
the option handling code must be able to handle options starting at
any byte boundary.
Add a test case for the basic option handling.
Create structures describing Identity Association IDentifiers and
IPv6 lease addresses.
[tomegun: initialize the IAID when client is started. Base this off of the
predictable udev names, if available, as these satisfy the requirement of
the IAID, and base it off the mac addres otherwise, as that is the best we
have.]
Provide functions to bind the ICMPv6 socket to the approriate interface
and set multicast sending and receiving according to RFC 3493, section
5.2. and RFC 3542, sections 3. and 3.3. Filter out all ICMPv6 messages
except Router Advertisements for the socket in question according to
RFC 3542, section 3.2.
Send Router Solicitations to the all routers multicast group as
described in RFC 4861, section 6. and act on the received Router
Advertisments according to section 6.3.7.
Implement a similar API for ICMPv6 handling as is done for DHCPv4 and
DHCPv6.
