Crate simple_dns

Pure Rust implementation to work with DNS packets

You can parse or write a DNS packet by using Packet or PacketBuf structs

Packet

Packet holds references for the original data and it is more suitable for situations where you need to manipulate the packet before generating the final bytes buffer

let question = Question::new(Name::new_unchecked("_srv._udp.local"), QTYPE::TXT, QCLASS::IN, false);
let resource = ResourceRecord::new(Name::new_unchecked("_srv._udp.local"), CLASS::IN, 10, RData::A(A { address: 10 }));

let mut packet = Packet::new_query(1, false);
packet.questions.push(question);
packet.additional_records.push(resource);

let bytes = packet.build_bytes_vec();
assert!(bytes.is_ok());

It doesn’t matter what order the resources are added, the packet will be built only when build_bytes_vec is called

To parse the contents of a buffer into a packet, you need call call Packet::parse

let bytes = b"\x00\x03\x01\x00\x00\x01\x00\x00\x00\x00\x00\x00\x06\x67\x6f\x6f\x67\x6c\x65\x03\x63\x6f\x6d\x00\x00\x01\x00\x01";
let packet = Packet::parse(&bytes[..]);
assert!(packet.is_ok());

PacketBuf

PacketBuf holds an internal buffer that is populated right when a resource is added.
It DOES matter the order in which the resources are added

let question = Question::new(Name::new_unchecked("_srv._udp.local"), QTYPE::TXT, QCLASS::IN, false);
let resource = ResourceRecord::new(Name::new_unchecked("_srv._udp.local"), CLASS::IN, 10, RData::A(A { address: 10 }));

let mut packet = PacketBuf::new(PacketHeader::new_query(1, false));
assert!(packet.add_answer(&resource).is_ok());
assert!(packet.add_question(&question).is_err()); //This will fail, since an answer is already added

It is possible to create a PacketBuf from a buffer by calling PacketBuf::from, but be aware that this will clone the contents from the buffer

Modules

rdata

Structs

CharacterString	CharacterString is expressed in one or two ways:
Name	A Name represents a domain-name, which consists of character strings separated by dots. Each section of a name is called label ex: google.com consists of two labels google and com
Packet	Represents a DNS message packet
PacketBuf	Owned version of Packet that contains a internal buffer. This struct fills the internal buffer on the fly, because of this, it imposes some constraints. You have to build the packet in order. ex: It is not possible to add a question after an answer
PacketHeader	Contains general information about the packet
PacketSectionIter	Iterate over the questions of a PacketBuf If a question is not valid, the iterator will stop
Question	Question represents a query in the DNS Packet
ResourceRecord	Resource Records are used to represent the answer, authority, and additional sections in DNS packets.

Enums

CLASS	Possible CLASS values for a Resource in a DNS packet Each value is described according to its own RFC
OPCODE	Possible OPCODE values for a DNS packet, use to specify the type of operation. RFC 1035: 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.
QCLASS	Possible QCLASS values for a Question in a DNS packet Each value is described according to its own RFC
QTYPE	Possible QTYPE values for a Question in a DNS packet Each value is described according to its own RFC
RCODE	Possible RCODE values for a DNS packet RFC 1035 Response code - this 4 bit field is set as part of responses. The values have the following interpretation
SimpleDnsError	Error types for SimpleDns
TYPE	Possible TYPE values in DNS Resource Records Each value is described according to its own RFC

Traits

DnsPacketContent

The maximum DNS packet size is 9000 bytes less the maximum sizes of the IP (60) and UDP (8) headers. Represents anything that can be part of a dns packet (Question, Resource Record, RData)

Type Definitions

Result

Alias type for Result<T, SimpleDnsError>;