Enum Icmpv6Type

pub enum Icmpv6Type {
    Unknown {
        type_u8: u8,
        code_u8: u8,
        bytes5to8: [u8; 4],
    },
    DestinationUnreachable(DestUnreachableCode),
    PacketTooBig {
        mtu: u32,
    },
    TimeExceeded(TimeExceededCode),
    ParameterProblem(ParameterProblemHeader),
    EchoRequest(IcmpEchoHeader),
    EchoReply(IcmpEchoHeader),
    RouterSolicitation,
    RouterAdvertisement(RouterAdvertisementHeader),
    NeighborSolicitation,
    NeighborAdvertisement(NeighborAdvertisementHeader),
    Redirect,
}

Different kinds of ICMPv6 messages.

The data stored in this enum corresponds to the statically sized data at the start of an ICMPv6 packet without the checksum. If you also need the checksum you can package and Icmpv6Type value in an Icmpv6Header struct.

Decoding Example (complete packet):

use etherparse::PacketHeaders;

let headers = PacketHeaders::from_ethernet_slice(&packet).unwrap();

use etherparse::TransportHeader::*;
match headers.transport {
    Some(Icmpv6(icmp)) => {
        use etherparse::Icmpv6Type::*;
        match icmp.icmp_type {
            // Unknown is used when further decoding is currently not supported for the icmp type & code.
            // You can still further decode the packet on your own by using the raw data in this enum
            // together with `headers.payload` (contains the packet data after the 8th byte)
            Unknown{ type_u8, code_u8, bytes5to8 } => println!("Unknown{{ type_u8: {}, code_u8: {}, bytes5to8: {:?} }}", type_u8, code_u8, bytes5to8),
            DestinationUnreachable(header) => println!("{:?}", header),
            PacketTooBig { mtu } => println!("TimeExceeded{{ mtu: {} }}", mtu),
            TimeExceeded(code) => println!("{:?}", code),
            ParameterProblem(header) => println!("{:?}", header),
            EchoRequest(header) => println!("{:?}", header),
            EchoReply(header) => println!("{:?}", header),
            RouterSolicitation => println!("RouterSolicitation"),
            RouterAdvertisement(header) => println!("{:?}", header),
            NeighborSolicitation => println!("NeighborSolicitation"),
            NeighborAdvertisement(header) => println!("{:?}", header),
            Redirect => println!("Redirect"),
        }
    },
    _ => {},
}

Encoding Example (only ICMPv6 part)

To get the on wire bytes of an Icmpv6Type it needs to get packaged into a Icmpv6Header so the checksum gets calculated.

use etherparse::{Icmpv6Type, icmpv6::DestUnreachableCode};
let t = Icmpv6Type::DestinationUnreachable(
    DestUnreachableCode::Address
);

// to calculate the checksum the ip header and the payload
// (in case of dest unreachable the invoking packet) are needed
let header = t.to_header(ip_header.source, ip_header.destination, &invoking_packet).unwrap();

// an ICMPv6 packet is composed of the header and payload
let mut packet = Vec::with_capacity(header.header_len() + invoking_packet.len());
packet.extend_from_slice(&header.to_bytes());
packet.extend_from_slice(&invoking_packet);

Variants

Unknown

In case of an unknown icmp type is received the header elements of the first 8 bytes/octets are stored raw in this enum value.

What is part of the header for Icmpv6Type::Unknown?

For unknown ICMPv6 type & code combination the first 8 bytes are stored in the Icmpv6Header and the rest is stored in the payload (Icmpv6Slice::payload or PacketHeaders::payload).

0               1               2               3               4
+---------------------------------------------------------------+  -
|     type_u8   |    code_u8    |  checksum (in Icmpv6Header)   |  |
+---------------------------------------------------------------+  | part of header & type
|                          bytes5to8                            |  ↓
+---------------------------------------------------------------+  -
|                                                               |  |
...                           ...                             ...  | part of payload
|                                                               |  ↓
+---------------------------------------------------------------+  -

Fields

type_u8: u8

ICMPv6 type (present in the first byte of the ICMPv6 packet).

code_u8: u8

ICMPv6 code (present in the 2nd byte of the ICMPv6 packet).

bytes5to8: [u8; 4]

Bytes located at th 5th, 6th, 7th and 8th position of the ICMP packet.

DestinationUnreachable(DestUnreachableCode)

Message sent to inform the client that the destination is unreachable for some reason.

What is part of the header for Icmpv6Type::DestinationUnreachable?

For the Icmpv6Type::DestinationUnreachable type the first 8 bytes/octets of the ICMPv6 packet are part of the header. The unused part is not stored and droped. The offending packet is stored in the payload part of the packet (Icmpv6Slice::payload & PacketHeaders::payload) and is not part of the Icmpv6Header.

0               1               2               3               4
+---------------------------------------------------------------+  -
|       1       | [value as u8] |  checksum (in Icmpv6Header)   |  |
+---------------------------------------------------------------+  | part of header & type
|                           <unused>                            |  ↓
+---------------------------------------------------------------+  -
|                                                               |  |
|     <As much of invoking packet as possible without           |  | part of payload
...   the ICMPv6 packet exceeding the minimum IPv6 MTU>       ...  |
|                                                               |  ↓
+---------------------------------------------------------------+  -

RFC 4443 Description

A Destination Unreachable message SHOULD be generated by a router, or by the IPv6 layer in the originating node, in response to a packet that cannot be delivered to its destination address for reasons other than congestion. (An ICMPv6 message MUST NOT be generated if a packet is dropped due to congestion.)

PacketTooBig

Sent if a packet to too big to be forwarded.

What is part of the header for Icmpv6Type::PacketTooBig?

For the Icmpv6Type::PacketTooBig type the first 8 bytes/octets of the ICMPv6 packet are part of the header. The offending packet is stored in the payload part of the packet (Icmpv6Slice::payload & PacketHeaders::payload) and is not part of the Icmpv6Header.

0               1               2               3               4
+---------------------------------------------------------------+  -
|       2       |       0       |  checksum (in Icmpv6Header)   |  |
+---------------------------------------------------------------+  | part of header & type
|                              mtu                              |  ↓
+---------------------------------------------------------------+  -
|                                                               |  |
|     <As much of invoking packet as possible without           |  | part of payload
...   the ICMPv6 packet exceeding the minimum IPv6 MTU>       ...  |
|                                                               |  ↓
+---------------------------------------------------------------+  -

RFC 4443 Description

A Packet Too Big MUST be sent by a router in response to a packet that it cannot forward because the packet is larger than the MTU of the outgoing link. The information in this message is used as part of the Path MTU Discovery process.

Fields

mtu: u32

The Maximum Transmission Unit of the next-hop link.

TimeExceeded(TimeExceededCode)

Generated when a datagram had to be discarded due to the hop limit field reaching zero.

What is part of the header for Icmpv6Type::TimeExceeded?

For the Icmpv6Type::TimeExceeded type the first 8 bytes/octets of the ICMPv6 packet are part of the header. The unused part is not stored and droped. The offending packet is stored in the payload part of the packet (Icmpv6Slice::payload & PacketHeaders::payload) and is not part of the Icmpv6Header.

0               1               2               3               4
+---------------------------------------------------------------+  -
|       3       | [value as u8] |  checksum (in Icmpv6Header)   |  |
+---------------------------------------------------------------+  | part of header & type
|                           <unused>                            |  ↓
+---------------------------------------------------------------+  -
|                                                               |  |
|     <As much of invoking packet as possible without           |  | part of payload
...   the ICMPv6 packet exceeding the minimum IPv6 MTU>       ...  |
|                                                               |  ↓
+---------------------------------------------------------------+  -

RFC 4443 Description

If a router receives a packet with a Hop Limit of zero, or if a router decrements a packet’s Hop Limit to zero, it MUST discard the packet and originate an ICMPv6 Time Exceeded message with Code 0 to the source of the packet. This indicates either a routing loop or too small an initial Hop Limit value.

An ICMPv6 Time Exceeded message with Code 1 is used to report fragment reassembly timeout, as specified in [IPv6, Section 4.5].

ParameterProblem(ParameterProblemHeader)

Sent if there is a problem with a parameter in a received packet.

What is part of the header for Icmpv6Type::ParameterProblem?

For the Icmpv6Type::ParameterProblem type the first 8 bytes/octets of the ICMPv6 packet are part of the header. The unused part is not stored and droped. The offending packet is stored in the payload part of the packet (Icmpv6Slice::payload & PacketHeaders::payload) and is not part of the Icmpv6Header.

0               1               2               3               4
+---------------------------------------------------------------+  -
|       4       | [value].code  |  checksum (in Icmpv6Header)   |  |
+---------------------------------------------------------------+  | part of header & type
|                        [value].pointer                        |  ↓
+---------------------------------------------------------------+  -
|                                                               |  |
|     <As much of invoking packet as possible without           |  | part of payload
...   the ICMPv6 packet exceeding the minimum IPv6 MTU>       ...  |
|                                                               |  ↓
+---------------------------------------------------------------+  -

RFC 4443 Description

If an IPv6 node processing a packet finds a problem with a field in the IPv6 header or extension headers such that it cannot complete processing the packet, it MUST discard the packet and SHOULD originate an ICMPv6 Parameter Problem message to the packet’s source, indicating the type and location of the problem.

EchoRequest(IcmpEchoHeader)

Requesting an EchoReply from the receiver.

What is part of the header for Icmpv6Type::EchoRequest?

For the Icmpv6Type::EchoRequest type the first 8 bytes/octets of the ICMPv6 packet are part of the header. This includes the id and seq fields. The data part of the ICMP echo request packet is part of the payload (Icmpv6Slice::payload & PacketHeaders::payload) and not part of the Icmpv6Header.

0               1               2               3               4
+---------------------------------------------------------------+  -
|      128      |       0       |  checksum (in Icmpv6Header)   |  |
+---------------------------------------------------------------+  | part of header & type
|          [value].id           |         [value].seq           |  ↓
+---------------------------------------------------------------+  -
|                                                               |  |
...                          <data>                           ...  | part of payload
|                                                               |  ↓
+---------------------------------------------------------------+  -

RFC 4443 Description

Every node MUST implement an ICMPv6 Echo responder function that receives Echo Requests and originates corresponding Echo Replies. A node SHOULD also implement an application-layer interface for originating Echo Requests and receiving Echo Replies, for diagnostic purposes.

EchoReply(IcmpEchoHeader)

Response to an EchoRequest message.

What is part of the header for Icmpv6Type::EchoReply?

For the Icmpv6Type::EchoReply type the first 8 bytes/octets of the ICMPv6 packet are part of the header. This includes the id and seq fields. The data part of the ICMP echo request packet is part of the payload (Icmpv6Slice::payload & PacketHeaders::payload) and not part of the Icmpv6Header.

0               1               2               3               4
+---------------------------------------------------------------+  -
|      129      |       0       |  checksum (in Icmpv6Header)   |  |
+---------------------------------------------------------------+  | part of header & type
|          [value].id           |         [value].seq           |  ↓
+---------------------------------------------------------------+  -
|                                                               |  |
...                          <data>                           ...  | part of payload
|                                                               |  ↓
+---------------------------------------------------------------+  -

RFC 4443 Description

Every node MUST implement an ICMPv6 Echo responder function that receives Echo Requests and originates corresponding Echo Replies. A node SHOULD also implement an application-layer interface for originating Echo Requests and receiving Echo Replies, for diagnostic purposes.

The source address of an Echo Reply sent in response to a unicast Echo Request message MUST be the same as the destination address of that Echo Request message.

An Echo Reply SHOULD be sent in response to an Echo Request message sent to an IPv6 multicast or anycast address. In this case, the source address of the reply MUST be a unicast address belonging to the interface on which the Echo Request message was received.

The data received in the ICMPv6 Echo Request message MUST be returned entirely and unmodified in the ICMPv6 Echo Reply message.

RouterSolicitation

Router Solicitation message header (part of “Neighbor Discovery Protocol” RFC 4861).

What is part of the header for Icmpv6Type::RouterSolicitation?

For the Icmpv6Type::RouterSolicitation type the first 8 bytes/octets of the ICMPv6 packet are part of the header.

The options part of the ICMP Router Solicitation packet is part of the payload (Icmpv6Slice::payload & PacketHeaders::payload) and not part of the Icmpv6Header.

0               1               2               3               4
+---------------------------------------------------------------+  -
|      133      |       0       |  checksum (in Icmpv6Header)   |  |
+---------------------------------------------------------------+  | part of header & type
|                           <unused>                            |  ↓
+---------------------------------------------------------------+  -
|   Options ...                                                 |  | part of payload
|                                                               |  ↓
+-----------------                                                 -

RFC 4861 Description

Hosts send Router Solicitations in order to prompt routers to generate Router Advertisements quickly.

RouterAdvertisement(RouterAdvertisementHeader)

Router Advertisement message header (part of “Neighbor Discovery Protocol” RFC 4861).

What is part of the header for Icmpv6Type::RouterAdvertisement?

For the Icmpv6Type::RouterAdvertisement type the first 8 bytes/octets of the ICMPv6 packet are part of the header.

The options part of the ICMP Router Advertisement packet is part of the payload (Icmpv6Slice::payload & PacketHeaders::payload) and not part of the Icmpv6Header.

0               1               2               3               4
+---------------------------------------------------------------+  -
|      134      |       0       |  checksum (in Icmpv6Header)   |  |
+---------------------------------------------------------------+  | part of header & type
| Cur Hop Limit |M|O|  Reserved |     Router Lifetime           |  ↓
+---------------------------------------------------------------+  -
|                        Reachable Time                         |  |
+---------------------------------------------------------------+  |
|                         Retrans Timer                         |  | part of payload
+---------------------------------------------------------------+  |
|   Options ...                                                 |  ↓
+-----------------                                                 -

RFC 4861 Description

Routers send out Router Advertisement messages periodically, or in response to Router Solicitations.

NeighborSolicitation

Requesting the link-layer address of a target node (part of “Neighbor Discovery Protocol” RFC 4861).

What is part of the header for Icmpv6Type::NeighborSolicitation?

For the Icmpv6Type::NeighborSolicitation type the first 8 bytes/octets of the ICMPv6 packet are part of the header.

The target address & options of the ICMP Neighbor Solicitation packet is part of the payload (Icmpv6Slice::payload & PacketHeaders::payload) and not part of the Icmpv6Header.

0               1               2               3               4
+---------------------------------------------------------------+  -
|      135      |       0       |  checksum (in Icmpv6Header)   |  |
+---------------------------------------------------------------+  | part of header & type
|                           <unused>                            |  ↓
+---------------------------------------------------------------+  -
|                                                               |  |
|                       Target Address                          |  |
|                                                               |  | part of payload
+---------------------------------------------------------------+  |
|   Options ...                                                    ↓
+-----------------                                                 -

RFC 4861 Description

Nodes send Neighbor Solicitations to request the link-layer address of a target node while also providing their own link-layer address to the target. Neighbor Solicitations are multicast when the node needs to resolve an address and unicast when the node seeks to verify the reachability of a neighbor.

NeighborAdvertisement(NeighborAdvertisementHeader)

Header of “Neighbor Advertisement” message (part of “Neighbor Discovery Protocol” RFC 4861).

What is part of the header for Icmpv6Type::NeighborAdvertisement?

For the Icmpv6Type::NeighborAdvertisement type the first 8 bytes/octets of the ICMPv6 packet are part of the header. This includes 3 bits for

• router
• solicited
• override

The target address & options of the ICMP Neighbor Advertisement packet is part of the payload (Icmpv6Slice::payload & PacketHeaders::payload) and not part of the Icmpv6Header.

0               1               2               3               4
+---------------------------------------------------------------+  -
|      136      |       0       |  checksum (in Icmpv6Header)   |  |
+---------------------------------------------------------------+  | part of header & type
|R|S|O|                    <unused>                             |  ↓
+---------------------------------------------------------------+  -
|                                                               |  |
|                       Target Address                          |  |
|                                                               |  | part of payload
+---------------------------------------------------------------+  |
|   Options ...                                                    ↓
+-----------------                                                 -

RFC 4861 Description

A node sends Neighbor Advertisements in response to Neighbor Solicitations and sends unsolicited Neighbor Advertisements in order to (unreliably) propagate new information quickly.

R Router flag. When set, the R-bit indicates that the sender is a router. The R-bit is used by Neighbor Unreachability Detection to detect a router that changes to a host.

S Solicited flag. When set, the S-bit indicates that the advertisement was sent in response to a Neighbor Solicitation from the Destination address. The S-bit is used as a reachability confirmation for Neighbor Unreachability Detection. It MUST NOT be set in multicast advertisements or in unsolicited unicast advertisements.

O Override flag. When set, the O-bit indicates that the advertisement should override an existing cache entry and update the cached link-layer address. When it is not set the advertisement will not update a cached link-layer address though it will update an existing Neighbor Cache entry for which no link-layer address is known. It SHOULD NOT be set in solicited advertisements for anycast addresses and in solicited proxy advertisements. It SHOULD be set in other solicited advertisements and in unsolicited advertisements.

Redirect

Header of “Redirect” message (part of “Neighbor Discovery Protocol” RFC 4861).

What is part of the header for Icmpv6Type::Redirect?

For the Icmpv6Type::Redirect type the first 8 bytes/octets of the ICMPv6 packet are part of the header.

The “target address”, “destination address” & options part of the ICMP Redirect packet is part of the payload (Icmpv6Slice::payload & PacketHeaders::payload) and not part of the Icmpv6Header.

0               1               2               3               4
+---------------------------------------------------------------+  -
|      137      |       0       |  checksum (in Icmpv6Header)   |  |
+---------------------------------------------------------------+  | part of header & type
|                           <unused>                            |  ↓
+---------------------------------------------------------------+  -
|                                                               |  |
|                       Target Address                          |  |
|                                                               |  |
+---------------------------------------------------------------+  |
|                                                               |  | part of payload
|                    Destination Address                        |  |
|                                                               |  |
+---------------------------------------------------------------+  |
|   Options ...                                                    ↓
+-----------------                                                 -                                             -

RFC 4861 Description

Routers send Redirect packets to inform a host of a better first-hop node on the path to a destination. Hosts can be redirected to a better first-hop router but can also be informed by a redirect that the destination is in fact a neighbor. The latter is accomplished by setting the ICMP Target Address equal to the ICMP Destination Address.

Implementations

impl Icmpv6Type

pub fn type_u8(&self) -> u8

Returns the type value (first byte of the ICMPv6 header) of this type.

pub fn code_u8(&self) -> u8

Returns the code value (second byte of the ICMPv6 header) of this type.

pub fn calc_checksum( &self, source_ip: [u8; 16], destination_ip: [u8; 16], payload: &[u8], ) -> Result<u16, ValueTooBigError<usize>>

Calculates the checksum of the ICMPv6 header.

Warning: Don't use this method to verfy if a checksum of a received packet is correct. This method assumes that all unused bytes are filled with zeros. If this is not the case the computed checksum value will will be incorrect for a received packet.

If you want to verify that a received packet has a correct checksum use Icmpv6Slice::is_checksum_valid instead.

pub fn to_header( self, source_ip: [u8; 16], destination_ip: [u8; 16], payload: &[u8], ) -> Result<Icmpv6Header, ValueTooBigError<usize>>

Creates a header with the correct checksum.

pub fn header_len(&self) -> usize

Serialized length of the header in bytes/octets.

Note that this size is not the size of the entire ICMPv6 packet but only the header.

pub fn fixed_payload_size(&self) -> Option<usize>

If the ICMP type has a fixed size returns the number of bytes that should be present after the header of this type.

Trait Implementations

impl Clone for Icmpv6Type

fn clone(&self) -> Icmpv6Type

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Icmpv6Type

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Hash for Icmpv6Type

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for Icmpv6Type

fn cmp(&self, other: &Icmpv6Type) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for Icmpv6Type

fn eq(&self, other: &Icmpv6Type) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for Icmpv6Type

fn partial_cmp(&self, other: &Icmpv6Type) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Copy for Icmpv6Type

impl Eq for Icmpv6Type

impl StructuralPartialEq for Icmpv6Type