pub struct SVCB { /* private fields */ }
Expand description
draft-ietf-dnsop-svcb-https-03 SVCB and HTTPS RRs for DNS, February 2021
2.2. RDATA wire format
The RDATA for the SVCB RR consists of:
* a 2 octet field for SvcPriority as an integer in network byte
order.
* the uncompressed, fully-qualified TargetName, represented as a
sequence of length-prefixed labels as in Section 3.1 of [RFC1035].
* the SvcParams, consuming the remainder of the record (so smaller
than 65535 octets and constrained by the RDATA and DNS message
sizes).
When the list of SvcParams is non-empty (ServiceMode), it contains a
series of SvcParamKey=SvcParamValue pairs, represented as:
* a 2 octet field containing the SvcParamKey as an integer in
network byte order. (See Section 14.3.2 for the defined values.)
* a 2 octet field containing the length of the SvcParamValue as an
integer between 0 and 65535 in network byte order (but constrained
by the RDATA and DNS message sizes).
* an octet string of this length whose contents are in a format
determined by the SvcParamKey.
SvcParamKeys SHALL appear in increasing numeric order.
Clients MUST consider an RR malformed if:
* the end of the RDATA occurs within a SvcParam.
* SvcParamKeys are not in strictly increasing numeric order.
* the SvcParamValue for an SvcParamKey does not have the expected
format.
Note that the second condition implies that there are no duplicate
SvcParamKeys.
If any RRs are malformed, the client MUST reject the entire RRSet and
fall back to non-SVCB connection establishment.
Implementations
sourceimpl SVCB
impl SVCB
sourcepub fn new(
svc_priority: u16,
target_name: Name,
svc_params: Vec<(SvcParamKey, SvcParamValue)>
) -> Self
pub fn new(
svc_priority: u16,
target_name: Name,
svc_params: Vec<(SvcParamKey, SvcParamValue)>
) -> Self
Create a new SVCB record from parts
It is up to the caller to validate the data going into the record
sourcepub fn svc_priority(&self) -> u16
pub fn svc_priority(&self) -> u16
draft-ietf-dnsop-svcb-https-03 SVCB and HTTPS RRs for DNS, February 2021
2.4.1. SvcPriority
When SvcPriority is 0 the SVCB record is in AliasMode
(Section 2.4.2). Otherwise, it is in ServiceMode (Section 2.4.3).
Within a SVCB RRSet, all RRs SHOULD have the same Mode. If an RRSet
contains a record in AliasMode, the recipient MUST ignore any
ServiceMode records in the set.
RRSets are explicitly unordered collections, so the SvcPriority field
is used to impose an ordering on SVCB RRs. SVCB RRs with a smaller
SvcPriority value SHOULD be given preference over RRs with a larger
SvcPriority value.
When receiving an RRSet containing multiple SVCB records with the
same SvcPriority value, clients SHOULD apply a random shuffle within
a priority level to the records before using them, to ensure uniform
load-balancing.
sourcepub fn target_name(&self) -> &Name
pub fn target_name(&self) -> &Name
draft-ietf-dnsop-svcb-https-03 SVCB and HTTPS RRs for DNS, February 2021
2.5. Special handling of "." in TargetName
If TargetName has the value "." (represented in the wire format as a
zero-length label), special rules apply.
2.5.1. AliasMode
For AliasMode SVCB RRs, a TargetName of "." indicates that the
service is not available or does not exist. This indication is
advisory: clients encountering this indication MAY ignore it and
attempt to connect without the use of SVCB.
2.5.2. ServiceMode
For ServiceMode SVCB RRs, if TargetName has the value ".", then the
owner name of this record MUST be used as the effective TargetName.
For example, in the following example "svc2.example.net" is the
effective TargetName:
example.com. 7200 IN HTTPS 0 svc.example.net.
svc.example.net. 7200 IN CNAME svc2.example.net.
svc2.example.net. 7200 IN HTTPS 1 . port=8002 echconfig="..."
svc2.example.net. 300 IN A 192.0.2.2
svc2.example.net. 300 IN AAAA 2001:db8::2
sourcepub fn svc_params(&self) -> &[(SvcParamKey, SvcParamValue)]
pub fn svc_params(&self) -> &[(SvcParamKey, SvcParamValue)]
See SvcParamKey
for details on each parameter
Trait Implementations
sourceimpl Display for SVCB
impl Display for SVCB
draft-ietf-dnsop-svcb-https-03 SVCB and HTTPS RRs for DNS, February 2021
simple.example. 7200 IN HTTPS 1 . alpn=h3
pool 7200 IN HTTPS 1 h3pool alpn=h2,h3 echconfig="123..."
HTTPS 2 . alpn=h2 echconfig="abc..."
@ 7200 IN HTTPS 0 www
_8765._baz.api.example.com. 7200 IN SVCB 0 svc4-baz.example.net.
impl Eq for SVCB
impl StructuralEq for SVCB
impl StructuralPartialEq for SVCB
Auto Trait Implementations
impl RefUnwindSafe for SVCB
impl Send for SVCB
impl Sync for SVCB
impl Unpin for SVCB
impl UnwindSafe for SVCB
Blanket Implementations
sourceimpl<T> BorrowMut<T> for T where
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
const: unstable · sourcefn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
sourceimpl<T> ToOwned for T where
T: Clone,
impl<T> ToOwned for T where
T: Clone,
type Owned = T
type Owned = T
The resulting type after obtaining ownership.
sourcefn clone_into(&self, target: &mut T)
fn clone_into(&self, target: &mut T)
🔬 This is a nightly-only experimental API. (
toowned_clone_into
)Uses borrowed data to replace owned data, usually by cloning. Read more