Struct trust_dns_proto::op::header::Header
source · pub struct Header { /* private fields */ }
Expand description
Metadata for the Message
struct.
RFC 1035, DOMAIN NAMES - IMPLEMENTATION AND SPECIFICATION, November 1987
4.1.1. Header section format
The header contains the following fields
1 1 1 1 1 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| ID |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
|QR| Opcode |AA|TC|RD|RA|ZZ|AD|CD| RCODE | /// AD and CD from RFC4035
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| QDCOUNT / ZCOUNT |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| ANCOUNT / PRCOUNT |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| NSCOUNT / UPCOUNT |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| ARCOUNT / ADCOUNT |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
where
Z Reserved for future use. Must be zero in all queries
and responses.
Implementations§
source§impl Header
impl Header
sourcepub fn response_from_request(header: &Self) -> Self
pub fn response_from_request(header: &Self) -> Self
Construct a new header based off the request header. This copies over the RD (recursion-desired) and CD (checking-disabled), as well as the op_code and id of the request.
See https://datatracker.ietf.org/doc/html/rfc6895#section-2
The AA, TC, RD, RA, and CD bits are each theoretically meaningful
only in queries or only in responses, depending on the bit. The AD
bit was only meaningful in responses but is expected to have a
separate but related meaning in queries (see Section 5.7 of
[RFC6840]). Only the RD and CD bits are expected to be copied from
the query to the response; however, some DNS implementations copy all
the query header as the initial value of the response header. Thus,
any attempt to use a "query" bit with a different meaning in a
response or to define a query meaning for a "response" bit may be
dangerous, given the existing implementation. Meanings for these
bits may only be assigned by a Standards Action.
sourcepub fn set_id(&mut self, id: u16) -> &mut Self
pub fn set_id(&mut self, id: u16) -> &mut Self
Sets the id of the message, for queries this should be random.
sourcepub fn set_message_type(&mut self, message_type: MessageType) -> &mut Self
pub fn set_message_type(&mut self, message_type: MessageType) -> &mut Self
Sets the message type, Queries and Updates both use Query.
sourcepub fn set_op_code(&mut self, op_code: OpCode) -> &mut Self
pub fn set_op_code(&mut self, op_code: OpCode) -> &mut Self
Set the operation code for the message
From the server is specifies that it is an authoritative response.
sourcepub fn set_truncated(&mut self, truncated: bool) -> &mut Self
pub fn set_truncated(&mut self, truncated: bool) -> &mut Self
Specifies that the records were too large for the payload.
See EDNS or TCP for resolutions to truncation.
sourcepub fn set_recursion_desired(&mut self, recursion_desired: bool) -> &mut Self
pub fn set_recursion_desired(&mut self, recursion_desired: bool) -> &mut Self
Specify that the resolver should recursively request data from upstream DNS nodes
sourcepub fn set_recursion_available(
&mut self,
recursion_available: bool
) -> &mut Self
pub fn set_recursion_available( &mut self, recursion_available: bool ) -> &mut Self
Specifies that recursion is available from this or the remote resolver
sourcepub fn set_authentic_data(&mut self, authentic_data: bool) -> &mut Self
pub fn set_authentic_data(&mut self, authentic_data: bool) -> &mut Self
Specifies that the data is authentic, i.e. the resolver believes all data to be valid through DNSSec
sourcepub fn set_checking_disabled(&mut self, checking_disabled: bool) -> &mut Self
pub fn set_checking_disabled(&mut self, checking_disabled: bool) -> &mut Self
Used during recursive resolution to specified if a resolver should or should not validate DNSSec signatures
sourcepub fn set_response_code(&mut self, response_code: ResponseCode) -> &mut Self
pub fn set_response_code(&mut self, response_code: ResponseCode) -> &mut Self
The low response code (original response codes before EDNS extensions)
sourcepub fn set_query_count(&mut self, query_count: u16) -> &mut Self
pub fn set_query_count(&mut self, query_count: u16) -> &mut Self
Number or query records in the message
sourcepub fn set_answer_count(&mut self, answer_count: u16) -> &mut Self
pub fn set_answer_count(&mut self, answer_count: u16) -> &mut Self
Number of answer records in the message
sourcepub fn set_name_server_count(&mut self, name_server_count: u16) -> &mut Self
pub fn set_name_server_count(&mut self, name_server_count: u16) -> &mut Self
Number of name server records in the message
sourcepub fn set_additional_count(&mut self, additional_count: u16) -> &mut Self
pub fn set_additional_count(&mut self, additional_count: u16) -> &mut Self
Number of additional records in the message
sourcepub fn id(&self) -> u16
pub fn id(&self) -> u16
ID A 16 bit identifier assigned by the program that
generates any kind of query. This identifier is copied
the corresponding reply and can be used by the requester
to match up replies to outstanding queries.
sourcepub fn message_type(&self) -> MessageType
pub fn message_type(&self) -> MessageType
QR A one bit field that specifies whether this message is a
query (0), or a response (1).
sourcepub fn op_code(&self) -> OpCode
pub fn op_code(&self) -> OpCode
OPCODE A four bit field that specifies kind of query in this
message. This value is set by the originator of a query
and copied into the response. The values are: <see super::op_code>
AA Authoritative Answer - this bit is valid in responses,
and specifies that the responding name server is an
authority for the domain name in question section.
Note that the contents of the answer section may have
multiple owner names because of aliases. The AA bit
corresponds to the name which matches the query name, or
the first owner name in the answer section.
sourcepub fn truncated(&self) -> bool
pub fn truncated(&self) -> bool
TC TrunCation - specifies that this message was truncated
due to length greater than that permitted on the
transmission channel.
sourcepub fn recursion_desired(&self) -> bool
pub fn recursion_desired(&self) -> bool
RD Recursion Desired - this bit may be set in a query and
is copied into the response. If RD is set, it directs
the name server to pursue the query recursively.
Recursive query support is optional.
sourcepub fn recursion_available(&self) -> bool
pub fn recursion_available(&self) -> bool
RA Recursion Available - this be is set or cleared in a
response, and denotes whether recursive query support is
available in the name server.
sourcepub fn authentic_data(&self) -> bool
pub fn authentic_data(&self) -> bool
RFC 4035, DNSSEC Resource Records, March 2005
3.1.6. The AD and CD Bits in an Authoritative Response
The CD and AD bits are designed for use in communication between
security-aware resolvers and security-aware recursive name servers.
These bits are for the most part not relevant to query processing by
security-aware authoritative name servers.
A security-aware name server does not perform signature validation
for authoritative data during query processing, even when the CD bit
is clear. A security-aware name server SHOULD clear the CD bit when
composing an authoritative response.
A security-aware name server MUST NOT set the AD bit in a response
unless the name server considers all RRsets in the Answer and
Authority sections of the response to be authentic. A security-aware
name server's local policy MAY consider data from an authoritative
zone to be authentic without further validation. However, the name
server MUST NOT do so unless the name server obtained the
authoritative zone via secure means (such as a secure zone transfer
mechanism) and MUST NOT do so unless this behavior has been
configured explicitly.
A security-aware name server that supports recursion MUST follow the
rules for the CD and AD bits given in Section 3.2 when generating a
response that involves data obtained via recursion.
sourcepub fn checking_disabled(&self) -> bool
pub fn checking_disabled(&self) -> bool
see is_authentic_data()
sourcepub fn response_code(&self) -> ResponseCode
pub fn response_code(&self) -> ResponseCode
RCODE Response code - this 4 bit field is set as part of
responses. The values have the following
interpretation: <see super::response_code>
sourcepub fn query_count(&self) -> u16
pub fn query_count(&self) -> u16
QDCOUNT an unsigned 16 bit integer specifying the number of
entries in the question section.
Return value
If this is a query, this will return the number of queries in the query section of the
sourcepub fn answer_count(&self) -> u16
pub fn answer_count(&self) -> u16
ANCOUNT an unsigned 16 bit integer specifying the number of
resource records in the answer section.
Return value
For query responses this is the number of records in the answer section, should be 0 for requests, for updates this is the count of prerequisite records.
sourcepub fn name_server_count(&self) -> u16
pub fn name_server_count(&self) -> u16
for queries this is the nameservers which are authorities for the SOA of the Record for updates this is the update record count
NSCOUNT an unsigned 16 bit integer specifying the number of name
server resource records in the authority records
section.
Return value
For query responses this is the number of authorities, or nameservers, in the name server section, for updates this is the number of update records being sent.
sourcepub fn additional_count(&self) -> u16
pub fn additional_count(&self) -> u16
ARCOUNT an unsigned 16 bit integer specifying the number of
resource records in the additional records section.
Return value
This is the additional record section count, this section may include EDNS options.
Trait Implementations§
source§impl<'r> BinDecodable<'r> for Header
impl<'r> BinDecodable<'r> for Header
source§fn read(decoder: &mut BinDecoder<'r>) -> ProtoResult<Self>
fn read(decoder: &mut BinDecoder<'r>) -> ProtoResult<Self>
source§fn from_bytes(bytes: &'r [u8]) -> ProtoResult<Self>
fn from_bytes(bytes: &'r [u8]) -> ProtoResult<Self>
source§impl BinEncodable for Header
impl BinEncodable for Header
source§fn emit(&self, encoder: &mut BinEncoder<'_>) -> ProtoResult<()>
fn emit(&self, encoder: &mut BinEncoder<'_>) -> ProtoResult<()>
source§impl PartialEq<Header> for Header
impl PartialEq<Header> for Header
source§impl PartialOrd<Header> for Header
impl PartialOrd<Header> for Header
1.0.0 · source§fn le(&self, other: &Rhs) -> bool
fn le(&self, other: &Rhs) -> bool
self
and other
) and is used by the <=
operator. Read more