### LinuxSllPayloadSlice Search Examples

Source: https://docs.rs/etherparse/latest/etherparse/struct.LinuxSllPayloadSlice.html?search=

Examples demonstrating how to search within LinuxSllPayloadSlice. These examples cover basic searches and more complex type-to-type conversions.

```APIDOC
## Search Examples

### Basic Search

This example shows a simple search for a common type.

```rust
// Example: Search for std::vec
let results = search("std::vec");
```

### Type Conversion Search

This example demonstrates searching for type conversions, such as converting a `u32` to a `bool`.

```rust
// Example: Search for u32 -> bool conversion
let results = search("u32 -> bool");
```

### Generic Type Conversion Search

This example illustrates searching for generic type conversions involving `Option`.

```rust
// Example: Search for Option<T>, (T -> U) -> Option<U>
let results = search("Option<T>, (T -> U) -> Option<U>");
```
```

--------------------------------

### Example Search: std::vec

Source: https://docs.rs/etherparse/latest/etherparse/ip_number/constant.ARIS.html?search=

An example search query demonstrating usage patterns.

```text
std::vec
```

--------------------------------

### Example: Parsing PacketHeaders from Ethernet Slice

Source: https://docs.rs/etherparse/latest/etherparse/struct.PacketHeaders.html?search=std%3A%3Avec

Demonstrates basic usage of PacketHeaders::from_ether_type to parse a packet slice starting with a specified EtherType. Shows how to access the different header components after successful parsing.

```rust
 use etherparse::{ether_type, PacketHeaders};

 match PacketHeaders::from_ether_type(ether_type::IPV4, packet) {
     Err(value) => println!("Err {:?}", value),
     Ok(value) => {
         println!("link: {:?}", value.link);
         println!("link_exts: {:?}", value.link_exts); // vlan & macsec
         println!("net: {:?}", value.net); // ip & arp
         println!("transport: {:?}", value.transport);
     }
 }

```

--------------------------------

### PacketBuilder Starting Options

Source: https://docs.rs/etherparse/latest/etherparse/struct.PacketBuilder.html?search=u32+-%3E+bool

Lists the initial options available for starting a packet construction with PacketBuilder.

```APIDOC
## Options
  * Starting Options: 
    * `PacketBuilder::ethernet2`
    * `PacketBuilder::linux_sll`
    * `PacketBuilder::ip`
    * `PacketBuilder::ipv4`
    * `PacketBuilder::ipv6`
```

--------------------------------

### Example Search Queries

Source: https://docs.rs/etherparse/latest/etherparse/ip_number/constant.GMTP.html?search=std%3A%3Avec

Illustrative examples of search queries that can be performed, demonstrating common patterns in Rust documentation searches.

```rust
std::vec
```

```rust
u32 -> bool
```

```rust
Option<T>, (T -> U) -> Option<U>
```

--------------------------------

### Example Search: u32 to bool

Source: https://docs.rs/etherparse/latest/etherparse/ip_number/constant.ARIS.html?search=

An example search query illustrating type conversion or mapping.

```text
u32 -> bool
```

--------------------------------

### Example: Parsing a packet from Ethernet using LaxSlicedPacket::from_ethernet

Source: https://docs.rs/etherparse/latest/etherparse/struct.LaxSlicedPacket.html?search=Option%3CT%3E%2C+%28T+-%3E+U%29+-%3E+Option%3CU%3E

Demonstrates basic usage of LaxSlicedPacket::from_ethernet to parse a packet slice starting from the Ethernet II header. It shows how to handle parsing errors and access different layers of the packet.

```rust
use etherparse::{
    ether_type,
    LaxSlicedPacket,
    LenSource,
};

match LaxSlicedPacket::from_ethernet(&packet) {
    Err(value) => {
        // An error is returned in case the ethernet II header could
        // not be parsed (other errors are stored in the "stop_err" field)
        println!("Err {:?}", value)
    },
    Ok(value) => {
        if let Some((stop_err, error_layer)) = value.stop_err.as_ref() {
            // error was encountered after parsing the ethernet 2 header
            println!("Error on layer {:?}: {:?}", error_layer, stop_err);
        }

        // parts that could be parsed without error
        println!("link: {:?}", value.link);
        println!("link_exts: {:?}", value.link_exts); // vlan & macsec

        // net (ip or arp)
        println!("net: {:?}", value.net);
        if let Some(ip_payload) = value.net.as_ref().map(|net| net.ip_payload_ref()).flatten() {
            // the ip payload len_source field can be used to check
            // if the slice length was used as a fallback value
            if ip_payload.len_source == LenSource::Slice {
                println!("  Used slice length as fallback to identify the IP payload");
            } else {
                println!("  IP payload could correctly be identified via the length field in the header");
            }
        }

        // transport (udp or tcp)
        println!("transport: {:?}", value.transport);
    }
};

```

--------------------------------

### PacketBuilder Example

Source: https://docs.rs/etherparse/latest/etherparse/struct.PacketBuilder.html

Demonstrates how to use PacketBuilder to construct a packet starting with an Ethernet II header, followed by an IPv4 header and a UDP header, and then serializing it with a payload.

```APIDOC
## Example: Generating a packet that starts with an Ethernet II header:
```rust
use etherparse::PacketBuilder;

let builder = PacketBuilder::
    ethernet2([1,2,3,4,5,6],     //source mac
              [7,8,9,10,11,12]) //destination mac
   .ipv4([192,168,1,1], //source ip
         [192,168,1,2], //destination ip
         20)            //time to life
   .udp(21,    //source port
        1234); //destination port

//payload of the udp packet
let payload = [1,2,3,4,5,6,7,8];

//get some memory to store the result
let mut result = Vec::<u8>::with_capacity(
                    builder.size(payload.len()));

//serialize
builder.write(&mut result, &payload).unwrap();
println!("{:?}", result);
```
```

--------------------------------

### Example: Parsing a packet using LaxSlicedPacket::from_ether_type

Source: https://docs.rs/etherparse/latest/etherparse/struct.LaxSlicedPacket.html?search=Option%3CT%3E%2C+%28T+-%3E+U%29+-%3E+Option%3CU%3E

Demonstrates basic usage of LaxSlicedPacket::from_ether_type to parse a packet slice starting with a specified EtherType. It shows how to handle parsing errors and access different layers of the packet.

```rust
use etherparse::{
    ether_type,
    LaxSlicedPacket,
};

let packet = LaxSlicedPacket::from_ether_type(ether_type::IPV4, packet);
if let Some((stop_err, error_layer)) = packet.stop_err.as_ref() {
    // in case an error is encountered parsing is stopped
    println!("Error on layer {:?}: {:?}", error_layer, stop_err);
}

// parts that could be parsed without error
println!("link: {:?}", packet.link);
println!("link_exts: {:?}", packet.link_exts); // vlan & macsec
println!("net: {:?}", packet.net); // ip & arp
println!("transport: {:?}", packet.transport);


```

--------------------------------

### IpHeaders Search Examples

Source: https://docs.rs/etherparse/latest/etherparse/enum.IpHeaders.html?search=

Examples of how to perform searches within IpHeaders. These demonstrate common search patterns.

```APIDOC
## Search Examples

### Example 1: Searching for a specific type
```
std::vec
```

### Example 2: Searching for type conversions
```
u32 -> bool
```

### Example 3: Searching for generic type transformations
```
Option<T>, (T -> U) -> Option<U>
```
```

--------------------------------

### Example Search: Option<T> mapping

Source: https://docs.rs/etherparse/latest/etherparse/ip_number/constant.ARIS.html?search=

An example search query showing functional programming patterns with Option.

```text
Option<T>, (T -> U) -> Option<U>
```

--------------------------------

### Example Searches for IpSlice

Source: https://docs.rs/etherparse/latest/etherparse/enum.IpSlice.html?search=

Demonstrates various ways to search within IpSlice, providing examples for common use cases.

```APIDOC
## Example Searches

This section provides examples of how to search within `IpSlice`.

### Search Examples

- `std::vec`
- `u32 -> bool`
- `Option<T>, (T -> U) -> Option<U>`
```

--------------------------------

### NdpOptionsIterator Search Examples

Source: https://docs.rs/etherparse/latest/etherparse/icmpv6/struct.NdpOptionsIterator.html?search=

Examples demonstrating how to search for different types of data within NdpOptionsIterator.

```APIDOC
## Search Examples

### Example 1: Searching for a specific type

```rust
// Example search for std::vec
let results = ndp_options_iterator.search("std::vec");
```

### Example 2: Searching for a type conversion

```rust
// Example search for u32 -> bool conversion
let results = ndp_options_iterator.search("u32 -> bool");
```

### Example 3: Searching for generic type transformations

```rust
// Example search for Option<T>, (T -> U) -> Option<U>
let results = ndp_options_iterator.search("Option<T>, (T -> U) -> Option<U>");
```
```

--------------------------------

### PayloadSlice Search Examples

Source: https://docs.rs/etherparse/latest/etherparse/enum.PayloadSlice.html?search=

Demonstrates example searches that can be performed with PayloadSlice.

```APIDOC
## Example Searches

### Search for a specific type
```
std::vec
```

### Search for type conversions
```
u32 -> bool
```

### Search for generic type transformations
```
Option<T>, (T -> U) -> Option<U>
```
```

--------------------------------

### NetSlice Enum Search Examples

Source: https://docs.rs/etherparse/latest/etherparse/enum.NetSlice.html?search=

Examples of how to perform searches within NetSlice enums.

```APIDOC
## Search Examples

### Example searches:

* `std::vec`
* `u32 -> bool`
* `Option<T>, (T -> U) -> Option<U>`
```

--------------------------------

### LenError Example

Source: https://docs.rs/etherparse/latest/etherparse/err/struct.LenError.html

An example demonstrating how to construct a LenError when there is not enough data available to decode a UDP header. This illustrates the usage of `required_len`, `len`, `layer`, `len_source`, and `layer_start_offset`.

```APIDOC
## §Examples:

An example for an error that could be returned when there is not enough data available to decode an UDP header would be:
```rust
use etherparse::*

err::LenError{
    // Expected to have at least the length of an UDP header present:
    required_len: UdpHeader::LEN,
    // Could not decode the UDP header:
    layer: err::Layer::UdpHeader,
    // There was only 1 byte left (not enough for an UDP header):
    len: 1,
    // The provided length was determined by the total length field in the
    // IPv4 header:
    len_source: LenSource::Ipv4HeaderTotalLen,
    // Offset in bytes from the start of decoding (ethernet in this) case
    // to the expected UDP header start:
    layer_start_offset: Ethernet2Header::LEN + Ipv4Header::MIN_LEN
};
```
```

--------------------------------

### Example LenError for Insufficient UDP Header Data

Source: https://docs.rs/etherparse/latest/etherparse/err/struct.LenError.html?search=

Illustrates creating a LenError instance when there isn't enough data to decode a UDP header. This example shows how to set the required length, the available length, the layer, the length source, and the offset.

```rust
use etherparse::*

err::LenError{
    // Expected to have at least the length of an UDP header present:
    required_len: UdpHeader::LEN,
    // Could not decode the UDP header:
    layer: err::Layer::UdpHeader,
    // There was only 1 byte left (not enough for an UDP header):
    len: 1,
    // The provided length was determined by the total length field in the
    // IPv4 header:
    len_source: LenSource::Ipv4HeaderTotalLen,
    // Offset in bytes from the start of decoding (ethernet in this) case
    // to the expected UDP header start:
    layer_start_offset: Ethernet2Header::LEN + Ipv4Header::MIN_LEN
};
```

--------------------------------

### IpFragOffset Usage Examples

Source: https://docs.rs/etherparse/latest/etherparse/struct.IpFragOffset.html?search=std%3A%3Avec

Demonstrates how to create and use IpFragOffset instances, including value conversion and error handling for out-of-range values.

```APIDOC
## IpFragOffset

The fragment offset is a 13 bit unsigned integer indicating the stating position of the payload of a packet relative to the originally fragmented packet payload. This value can be present in an `crate::Ipv4Header` or an `crate::Ipv6FragmentHeader`.

### Example Usage:

#### Using try_into:
```rust
use etherparse::IpFragOffset;

let frag_offset: IpFragOffset = 123.try_into().unwrap();
assert_eq!(frag_offset.value(), 123);

let value: u16 = frag_offset.into();
assert_eq!(123, value);
```

#### Using try_new:
```rust
use etherparse::IpFragOffset;
use etherparse::err::{ValueTooBigError, ValueType};

let frag_offset = IpFragOffset::try_new(123).unwrap();
assert_eq!(frag_offset.value(), 123);

// Maximum allowed value is 0b0001_1111_1111_1111
assert_eq!(
    IpFragOffset::try_new(IpFragOffset::MAX_U16 + 1),
    Err(ValueTooBigError{
        actual: IpFragOffset::MAX_U16 + 1,
        max_allowed: IpFragOffset::MAX_U16,
        value_type: ValueType::IpFragmentOffset,
    })
);
```

#### Using new_unchecked (unsafe):
```rust
use etherparse::IpFragOffset;

// Use only if you are certain the value is within the allowed range (0 to IpFragOffset::MAX_U16)
let frag_offset = unsafe {
    IpFragOffset::new_unchecked(123)
};
assert_eq!(frag_offset.value(), 123);
```

### Constants:

*   **MAX_U16**: The maximum value allowed for `IpFragOffset` (0x1FFF).
```

--------------------------------

### Get element index using pointer arithmetic

Source: https://docs.rs/etherparse/latest/etherparse/struct.TcpOptions.html?search=std%3A%3Avec

Use `element_offset` to find the index of an element within a slice using pointer arithmetic. It returns `None` if the element reference is not aligned to the start of an element.

```rust
let nums: &[u32] = &[1, 7, 1, 1];
let num = &nums[2];

assert_eq!(num, &1);
assert_eq!(nums.element_offset(num), Some(2));
```

```rust
let arr: &[[u32; 2]] = &[[0, 1], [2, 3]];
let flat_arr: &[u32] = arr.as_flattened();

let ok_elm: &[u32; 2] = flat_arr[0..2].try_into().unwrap();
let weird_elm: &[u32; 2] = flat_arr[1..3].try_into().unwrap();

assert_eq!(ok_elm, &[0, 1]);
assert_eq!(weird_elm, &[1, 2]);

assert_eq!(arr.element_offset(ok_elm), Some(0)); 
assert_eq!(arr.element_offset(weird_elm), None);
```

--------------------------------

### VlanPcp::try_new Example

Source: https://docs.rs/etherparse/latest/etherparse/struct.VlanPcp.html?search=std%3A%3Avec

Demonstrates creating a VlanPcp with a valid value and handling errors for out-of-range values.

```rust
use etherparse.VlanPcp;

let pcp = VlanPcp::try_new(2).unwrap();
assert_eq!(pcp.value(), 2);

// if a number that can not be represented in an 3 bit integer
// gets passed in an error is returned
use etherparse.err::{ValueTooBigError, ValueType};
assert_eq!(
    VlanPcp::try_new(VlanPcp::MAX_U8 + 1),
    Err(ValueTooBigError{
        actual: VlanPcp::MAX_U8 + 1,
        max_allowed: VlanPcp::MAX_U8,
        value_type: ValueType::VlanPcp,
    })
);
```

--------------------------------

### LaxSlicedPacket::from_ethernet Example

Source: https://docs.rs/etherparse/latest/etherparse/struct.LaxSlicedPacket.html?search=std%3A%3Avec

Demonstrates basic usage of LaxSlicedPacket::from_ethernet to parse a network packet slice starting from the Ethernet II header. Handles potential parsing errors and accesses parsed header information.

```rust
use etherparse::{
    ether_type,
    LaxSlicedPacket,
    LenSource,
};

match LaxSlicedPacket::from_ethernet(&packet) {
    Err(value) => {
        // An error is returned in case the ethernet II header could
        // not be parsed (other errors are stored in the "stop_err" field)
        println!("Err {:?}", value)
    },
    Ok(value) => {
        if let Some((stop_err, error_layer)) = value.stop_err.as_ref() {
            // error was encountered after parsing the ethernet 2 header
            println!("Error on layer {}: {:?}", error_layer, stop_err);
        }

        // parts that could be parsed without error
        println!("link: {:?}", value.link);
        println!("link_exts: {:?}", value.link_exts); // vlan & macsec

        // net (ip or arp)
        println!("net: {:?}", value.net);
        if let Some(ip_payload) = value.net.as_ref().map(|net| net.ip_payload_ref()).flatten() {
            // the ip payload len_source field can be used to check
            // if the slice length was used as a fallback value
            if ip_payload.len_source == LenSource::Slice {
                println!("  Used slice length as fallback to identify the IP payload");
            } else {
                println!("  IP payload could correctly be identified via the length field in the header");
            }
        }

        // transport (udp or tcp)
        println!("transport: {:?}", value.transport);
    }
};

```

--------------------------------

### Ipv4Options Conversion Examples

Source: https://docs.rs/etherparse/latest/etherparse/struct.Ipv4Options.html?search=Option%3CT%3E%2C+%28T+-%3E+U%29+-%3E+Option%3CU%3E

Demonstrates how to convert various data types into Ipv4Options, including static arrays, slices, and handling potential errors.

```APIDOC
## Ipv4Options Conversion Examples

### Description
Examples showing how to create `Ipv4Options` from different sources and how to handle errors.

### Example 1: Static sized arrays
```rust
use etherparse::Ipv4Options;

let options: Ipv4Options = [1,2,3,4].into();
assert_eq!(&options[..], &[1,2,3,4]);
```

### Example 2: Slices
```rust
use etherparse::Ipv4Options;

let some_data = vec![1,2,3,4,5,6,7,8];
let options: Ipv4Options = (&some_data[..]).try_into().unwrap();
assert_eq!(options.as_slice(), &[1,2,3,4,5,6,7,8]);
```

### Example 3: Error Handling for Invalid Length
```rust
use etherparse::err::ipv4::BadOptionsLen;
use etherparse::Ipv4Options;

let result = Ipv4Options::try_from(&[1,2,3][..]);
assert_eq!(result, Err(BadOptionsLen { bad_len: 3 }));
```
```

--------------------------------

### IpFragOffset Usage Examples

Source: https://docs.rs/etherparse/latest/etherparse/struct.IpFragOffset.html?search=Option%3CT%3E%2C+%28T+-%3E+U%29+-%3E+Option%3CU%3E

Demonstrates various ways to create and use the IpFragOffset struct, including conversion from u16, safe creation with try_new, and unsafe creation with new_unchecked.

```APIDOC
## IpFragOffset

### Description
The fragment offset is a 13 bit unsigned integer indicating the stating position of the payload of a packet relative to the originally fragmented packet payload. This value can be present in an `crate::Ipv4Header` or an `crate::Ipv6FragmentHeader`.

### Example Usage:
```rust
use etherparse::IpFragOffset;

// try into
{
    let frag_offset: IpFragOffset = 123.try_into().unwrap();
    assert_eq!(frag_offset.value(), 123);

    // fragment offset can always be converted back to an u16
    let value: u16 = frag_offset.into();
    assert_eq!(123, value);
}

// via try_new
{
    let frag_offset = IpFragOffset::try_new(123).unwrap();
    assert_eq!(frag_offset.value(), 123);

    // note that only 13 bit numbers are allowed (meaning
    // 0b0001_1111_1111_1111 is the maximum allowed value)
    use etherparse::err::{ValueTooBigError, ValueType};
    assert_eq!(
        IpFragOffset::try_new(IpFragOffset::MAX_U16 + 1),
        Err(ValueTooBigError{
            actual: IpFragOffset::MAX_U16 + 1,
            max_allowed: IpFragOffset::MAX_U16,
            value_type: ValueType::IpFragmentOffset,
        })
    );
}

// via new_unchecked
{
    // in case you are sure the number does not exceed the max
    // you can use the unsafe new_unchecked function
    let frag_offset = unsafe {
        // please make sure that the value is not greater than IpFragOffset::MAX_U16
        // before calling this method
        IpFragOffset::new_unchecked(123)
    };
    assert_eq!(frag_offset.value(), 123);
}
```
```

--------------------------------

### Basic Usage Example

Source: https://docs.rs/etherparse/latest/etherparse/struct.SlicedPacket.html?search=u32+-%3E+bool

Demonstrates how to use `SlicedPacket::from_ethernet` to parse a packet and access its different layers.

```APIDOC
## Examples

Basic usage:
```rust
 match SlicedPacket::from_ethernet(&packet) {
     Err(value) => println!("Err {:?}", value),
     Ok(value) => {
         println!("link: {:?}", value.link);
         println!("link_exts: {:?}", value.link_exts); // vlan & macsec
         println!("net: {:?}", value.net); // ip & arp
         println!("transport: {:?}", value.transport);
     }
 };
```
```

--------------------------------

### Example Usage of Ipv4Header

Source: https://docs.rs/etherparse/latest/etherparse/struct.Ipv4Header.html

Demonstrates creating, calculating checksum, serializing, and deserializing an IPv4 header.

```rust
use etherparse::{Ipv4Header, IpNumber};

let mut header = Ipv4Header {
    source: [1,2,3,4],
    destination: [1,2,3,4],
    time_to_live: 4,
    total_len: Ipv4Header::MIN_LEN as u16 + 100,
    protocol: IpNumber::UDP,
    ..Default::default()
};

// depending on your use case you might want to set the correct checksum
header.header_checksum = header.calc_header_checksum();

// header can be serialized into the "on the wire" format
// using the "write" or "to_bytes" methods
let bytes = header.to_bytes();

// IPv4 headers can be decoded via "read" or "from_slice"
let (decoded, slice_rest) = Ipv4Header::from_slice(&bytes).unwrap();
assert_eq!(header, decoded);
assert_eq!(slice_rest, &[]);

```

--------------------------------

### Example Usage of Ipv4Header

Source: https://docs.rs/etherparse/latest/etherparse/struct.Ipv4Header.html?search=

Demonstrates how to create an Ipv4Header instance, set its fields, calculate the header checksum, serialize it into bytes, and deserialize it back from a byte slice.

```APIDOC
## Example Usage:
```rust
use etherparse::{Ipv4Header, IpNumber};

let mut header = Ipv4Header {
    source: [1,2,3,4],
    destination: [1,2,3,4],
    time_to_live: 4,
    total_len: Ipv4Header::MIN_LEN as u16 + 100,
    protocol: IpNumber::UDP,
    ..Default::default()
};

// depending on your use case you might want to set the correct checksum
header.header_checksum = header.calc_header_checksum();

// header can be serialized into the "on the wire" format
// using the "write" or "to_bytes" methods
let bytes = header.to_bytes();

// IPv4 headers can be decoded via "read" or "from_slice"
let (decoded, slice_rest) = Ipv4Header::from_slice(&bytes).unwrap();
assert_eq!(header, decoded);
assert_eq!(slice_rest, &[]);
```
```

--------------------------------

### get

Source: https://docs.rs/etherparse/latest/etherparse/struct.TcpOptions.html

Safely gets a reference to an element or subslice using an index or range. Returns None if the index is out of bounds.

```APIDOC
## pub fn get<I>(&self, index: I) -> Option<&<I as SliceIndex<[T]>>::Output>
where I: SliceIndex<[T]>

### Description
Returns a reference to an element or subslice depending on the type of index. If given a position, returns a reference to the element at that position or `None` if out of bounds. If given a range, returns the subslice corresponding to that range, or `None` if out of bounds.

### Examples
```
let v = [10, 40, 30];
assert_eq!(Some(&40), v.get(1));
assert_eq!(Some(&[10, 40][..]), v.get(0..2));
assert_eq!(None, v.get(3));
assert_eq!(None, v.get(0..4));
```
```

--------------------------------

### Example Searches for Ipv6Slice

Source: https://docs.rs/etherparse/latest/etherparse/struct.Ipv6Slice.html?search=

Demonstrates various ways to search within Ipv6Slice, including searching for specific types, type conversions, and generic type manipulations.

```APIDOC
## Example Searches

This section provides examples of how to search within Ipv6Slice.

### Search Examples

- `std::vec`
- `u32 -> bool`
- `Option<T>, (T -> U) -> Option<U>`
```

--------------------------------

### Basic SIMD Slice Splitting

Source: https://docs.rs/etherparse/latest/etherparse/struct.Ipv4Options.html

Illustrates splitting a slice into prefix, middle SIMD types, and suffix using `as_simd`. This example shows a case where there are not enough elements for the middle SIMD part.

```rust
#![feature(portable_simd)]
use core::simd::prelude::*;

let short = &[1, 2, 3];
let (prefix, middle, suffix) = short.as_simd::<4>();
assert_eq!(middle, []); // Not enough elements for anything in the middle

// They might be split in any possible way between prefix and suffix
let it = prefix.iter().chain(suffix).copied();
assert_eq!(it.collect::<Vec<_>>(), vec![1, 2, 3]);
```

--------------------------------

### Get Element or Subslice by Index

Source: https://docs.rs/etherparse/latest/etherparse/struct.Ipv4Options.html

Use `get` to safely retrieve a reference to an element or subslice. Returns `None` if the index is out of bounds.

```rust
let v = [10, 40, 30];
assert_eq!(Some(&40), v.get(1));
assert_eq!(Some(&[10, 40][..]), v.get(0..2));
assert_eq!(None, v.get(3));
assert_eq!(None, v.get(0..4));
```

--------------------------------

### Get Last Element of a Slice

Source: https://docs.rs/etherparse/latest/etherparse/struct.Ipv4Options.html

Use `last` to safely get an immutable reference to the last element, returning `None` for empty slices.

```rust
let v = [10, 40, 30];
assert_eq!(Some(&30), v.last());

let w: &[i32] = &[];
assert_eq!(None, w.last());
```

--------------------------------

### Example: Parsing Packet Headers from IP Slice

Source: https://docs.rs/etherparse/latest/etherparse/struct.PacketHeaders.html?search=Option%3CT%3E%2C+%28T+-%3E+U%29+-%3E+Option%3CU%3E

Shows how to use `PacketHeaders::from_ip_slice` to parse IP packet data. It includes error handling and printing of the parsed header fields.

```rust
use etherparse::PacketHeaders;

match PacketHeaders::from_ip_slice(&packet) {
    Err(value) => println!("Err {:?}", value),
    Ok(value) => {
        println!("link: {:?}", value.link);
        println!("link_exts: {:?}", value.link_exts); // vlan & macsec
        println!("net: {:?}", value.net); // ip & arp
        println!("transport: {:?}", value.transport);
    }
}
```

--------------------------------

### Example Usage of Ipv4Header

Source: https://docs.rs/etherparse/latest/etherparse/struct.Ipv4Header.html?search=Option%3CT%3E%2C+%28T+-%3E+U%29+-%3E+Option%3CU%3E

Demonstrates how to create, serialize, and deserialize an Ipv4Header using the etherparse library.

```APIDOC
## Example Usage:

```rust
use etherparse::{Ipv4Header, IpNumber};

let mut header = Ipv4Header {
    source: [1,2,3,4],
    destination: [1,2,3,4],
    time_to_live: 4,
    total_len: Ipv4Header::MIN_LEN as u16 + 100,
    protocol: IpNumber::UDP,
    ..Default::default()
};

// depending on your use case you might want to set the correct checksum
header.header_checksum = header.calc_header_checksum();

// header can be serialized into the "on the wire" format
// using the "write" or "to_bytes" methods
let bytes = header.to_bytes();

// IPv4 headers can be decoded via "read" or "from_slice"
let (decoded, slice_rest) = Ipv4Header::from_slice(&bytes).unwrap();
assert_eq!(header, decoded);
assert_eq!(slice_rest, &[]);
```
```

--------------------------------

### SlicedPacket::from_ether_type

Source: https://docs.rs/etherparse/latest/etherparse/struct.SlicedPacket.html?search=

Parses a packet starting from a specified EtherType. This is useful when you want to bypass the Ethernet header and start parsing from a specific protocol type.

```APIDOC
## SlicedPacket::from_ether_type

### Description
Parses a packet starting from a specified EtherType.

### Method
`SlicedPacket::from_ether_type`

### Parameters
- `ether_type`: u16 - The EtherType to start parsing from.
- `packet`: &[u8] - The raw packet data to parse.

### Response
- `Result<SlicedPacket, String>` - Ok(SlicedPacket) on success, Err(String) on parsing failure.

### Request Example
```rust
// Example usage would be similar to from_ethernet, but specifying the ether_type
```
```

--------------------------------

### LenError Example: Insufficient Data

Source: https://docs.rs/etherparse/latest/etherparse/err/struct.LenError.html?search=std%3A%3Avec

An example demonstrating how to construct a LenError when there is not enough data available to decode a UDP header, highlighting the `required_len` and `len` fields.

```APIDOC
## Example: Insufficient Data for UDP Header

### Description
This example shows how to create a `LenError` instance to represent a scenario where the provided data slice is too short to contain a complete UDP header.

### Code
```rust
use etherparse::err::{LenError, LenSource, Layer};
use etherparse::{UdpHeader, Ethernet2Header, Ipv4Header};

let udp_header_error = LenError {
    // Expected to have at least the length of an UDP header present:
    required_len: UdpHeader::LEN,
    // Could not decode the UDP header:
    layer: Layer::UdpHeader,
    // There was only 1 byte left (not enough for an UDP header):
    len: 1,
    // The provided length was determined by the total length field in the
    // IPv4 header:
    len_source: LenSource::Ipv4HeaderTotalLen,
    // Offset in bytes from the start of decoding (ethernet in this) case
    // to the expected UDP header start:
    layer_start_offset: Ethernet2Header::LEN + Ipv4Header::MIN_LEN
};
```
```

--------------------------------

### Split Off Slice Starting with Third Element

Source: https://docs.rs/etherparse/latest/etherparse/struct.Ipv4Options.html

Removes and returns a subslice starting from the third element. The original slice is modified to contain the elements before the split point.

```rust
let mut slice: &[_] = &['a', 'b', 'c', 'd'];
let mut tail = slice.split_off(2..).unwrap();

assert_eq!(slice, &['a', 'b']);
assert_eq!(tail, &['c', 'd']);
```

--------------------------------

### Example: Parsing Packet Headers by EtherType

Source: https://docs.rs/etherparse/latest/etherparse/struct.PacketHeaders.html?search=Option%3CT%3E%2C+%28T+-%3E+U%29+-%3E+Option%3CU%3E

Demonstrates basic usage of `PacketHeaders::from_ether_type` to parse packet data. Handles potential parsing errors and prints decoded header information.

```rust
 use etherparse::{ether_type, PacketHeaders};

 match PacketHeaders::from_ether_type(ether_type::IPV4, packet) {
     Err(value) => println!("Err {:?}", value),
     Ok(value) => {
         println!("link: {:?}", value.link);
         println!("link_exts: {:?}", value.link_exts); // vlan & macsec
         println!("net: {:?}", value.net); // ip & arp
         println!("transport: {:?}", value.transport);
     }
 }
```

--------------------------------

### Example Search: Option<T>, (T -> U) -> Option<U>

Source: https://docs.rs/etherparse/latest/etherparse/ip_number/constant.FC.html?search=Option%3CT%3E%2C+%28T+-%3E+U%29+-%3E+Option%3CU%3E

Illustrates a common functional programming pattern for transforming Option types.

```rust
Option<T>, (T -> U) -> Option<U>

```

--------------------------------

### Get Reference to Underlying Array

Source: https://docs.rs/etherparse/latest/etherparse/struct.TcpOptions.html?search=Option%3CT%3E%2C+%28T+-%3E+U%29+-%3E+Option%3CU%3E

Use `as_array` to get a reference to the underlying array if its length exactly matches the specified size `N`. Returns `None` otherwise.

```rust
let slice = &[1, 2, 3];
let array_ref: Option<&[i32; 3]> = slice.as_array();
assert!(array_ref.is_some());

let wrong_size_ref: Option<&[i32; 2]> = slice.as_array();
assert!(wrong_size_ref.is_none());
```

--------------------------------

### IpDefragPool::new

Source: https://docs.rs/etherparse/latest/etherparse/defrag/struct.IpDefragPool.html

Creates a new instance of IpDefragPool.

```APIDOC
## IpDefragPool::new

### Description
Creates a new instance of IpDefragPool.

### Returns
- `IpDefragPool<Timestamp, CustomChannelId>` - A new IpDefragPool instance.
```

--------------------------------

### Get Last Chunk of Slice

Source: https://docs.rs/etherparse/latest/etherparse/struct.Ipv4Options.html

Use `last_chunk` with a const generic `N` to get an array reference to the last `N` elements. Returns `None` if the slice is too short.

```rust
let u = [10, 40, 30];
assert_eq!(Some(&[40, 30]), u.last_chunk::<2>());

let v: &[i32] = &[10];
assert_eq!(None, v.last_chunk::<2>());

let w: &[i32] = &[];
assert_eq!(Some(&[]), w.last_chunk::<0>());
```

--------------------------------

### Get First Chunk of Slice

Source: https://docs.rs/etherparse/latest/etherparse/struct.Ipv4Options.html

Use `first_chunk` with a const generic `N` to get an array reference to the first `N` elements. Returns `None` if the slice is too short.

```rust
let u = [10, 40, 30];
assert_eq!(Some(&[10, 40]), u.first_chunk::<2>());

let v: &[i32] = &[10];
assert_eq!(None, v.first_chunk::<2>());

let w: &[i32] = &[];
assert_eq!(Some(&[]), w.first_chunk::<0>());
```

--------------------------------

### Iterating over IPv4 Options

Source: https://docs.rs/etherparse/latest/etherparse/struct.Ipv4Options.html?search=std%3A%3Avec

Demonstrates how to iterate over IPv4 options using an iterator, showing the start and end ranges of each option.

```APIDOC
## Example

```rust
assert_eq!(iter.next(), Some(Range { start: 0, end: 0 }));
assert_eq!(iter.next(), Some(Range { start: 1, end: 3 }));
assert_eq!(iter.next(), Some(Range { start: 4, end: 4 }));
assert_eq!(iter.next(), Some(Range { start: 5, end: 6 }));
```
```

--------------------------------

### Ipv4Options::new

Source: https://docs.rs/etherparse/latest/etherparse/struct.Ipv4Options.html?search=u32+-%3E+bool

Creates a new, empty Ipv4Options instance.

```APIDOC
## Ipv4Options::new

### Description
Setup an empty options array.

### Returns
- `Ipv4Options`: An empty IPv4 options instance.
```

--------------------------------

### Get Slice as Underlying Array Reference

Source: https://docs.rs/etherparse/latest/etherparse/struct.TcpOptions.html?search=std%3A%3Avec

Use `as_array` to attempt to get a reference to the underlying array if its length exactly matches `N`. Returns `None` if lengths do not match.

```rust
let data = [1, 2, 3];
let slice = &data[..];

// This will succeed because N is 3, matching the slice length
let array_ref: Option<&[i32; 3]> = slice.as_array::<3>();
assert!(array_ref.is_some());

// This will fail because N is 2, not matching the slice length
let array_ref_fail: Option<&[i32; 2]> = slice.as_array::<2>();
assert!(array_ref_fail.is_none());
```

--------------------------------

### Example Searches for LaxEtherPayloadSlice

Source: https://docs.rs/etherparse/latest/etherparse/struct.LaxEtherPayloadSlice.html?search=

Demonstrates various ways to search within LaxEtherPayloadSlice, including searching for specific types, type conversions, and generic type transformations.

```APIDOC
## Example Searches

This section provides examples of search queries that can be performed.

### Search Patterns

- **Searching for a specific type:**
  `std::vec`

- **Searching for type conversions:**
  `u32 -> bool`

- **Searching for generic type transformations:**
  `Option<T>, (T -> U) -> Option<U>`
```

--------------------------------

### Get meaningful sender address bytes

Source: https://docs.rs/etherparse/latest/etherparse/struct.LinuxSllHeaderSlice.html

Get the meaningful bytes of the slice of the link layer address. This returns only the relevant part of the sender address based on the length field.

```rust
pub fn sender_address(&self) -> &'a [u8]
```

--------------------------------

### Get Raw Pointer to Slice Buffer

Source: https://docs.rs/etherparse/latest/etherparse/struct.Ipv4Options.html

Use `as_ptr` to get a raw pointer to the slice's buffer. Ensure the slice outlives the pointer and the memory is not mutated through this pointer.

```rust
let x = &[1, 2, 4];
let x_ptr = x.as_ptr();

unsafe {
    for i in 0..x.len() {
        assert_eq!(x.get_unchecked(i), &*x_ptr.add(i));
    }
}
```

--------------------------------

### VlanId::try_new Example

Source: https://docs.rs/etherparse/latest/etherparse/struct.VlanId.html?search=

Demonstrates creating a VlanId using try_new, which checks for valid 12-bit values. Shows successful creation and error handling for out-of-range values.

```rust
use etherparse.VlanId;

let vlanid = VlanId::try_new(2).unwrap();
assert_eq!(vlanid.value(), 2);

// if a number that can not be represented in an 12 bit integer
// gets passed in an error is returned
use etherparse.err.{ValueTooBigError, ValueType};
assert_eq!(
    VlanId::try_new(VlanId::MAX_U16 + 1),
    Err(ValueTooBigError{
        actual: VlanId::MAX_U16 + 1,
        max_allowed: VlanId::MAX_U16,
        value_type: ValueType::VlanId,
    })
);
```

--------------------------------

### Get Mutable Reference to Last N Items

Source: https://docs.rs/etherparse/latest/etherparse/struct.Ipv4Options.html

Use `last_chunk_mut` to get a mutable reference to the last N items of a slice. Returns `None` if the slice is shorter than N.

```rust
let x = &mut [0, 1, 2];

if let Some(last) = x.last_chunk_mut::<2>() {
    last[0] = 10;
    last[1] = 20;
}
assert_eq!(x, &[0, 10, 20]);

assert_eq!(None, x.last_chunk_mut::<4>());
```

--------------------------------

### IpFragOffset Creation and Conversion

Source: https://docs.rs/etherparse/latest/etherparse/struct.IpFragOffset.html

Demonstrates creating an IpFragOffset from an integer using try_into and try_new, and converting it back to a u16. Also shows error handling for values exceeding the maximum allowed.

```rust
use etherparse::IpFragOffset;

// try into
{
    let frag_offset: IpFragOffset = 123.try_into().unwrap();
    assert_eq!(frag_offset.value(), 123);

    // fragment offset can always be converted back to an u16
    let value: u16 = frag_offset.into();
    assert_eq!(123, value);
}

// via try_new
{
    let frag_offset = IpFragOffset::try_new(123).unwrap();
    assert_eq!(frag_offset.value(), 123);

    // note that only 13 bit numbers are allowed (
    // meaning
    // 0b0001_1111_1111_1111 is the maximum allowed value)
    use etherparse::err::{ValueTooBigError, ValueType};
    assert_eq!(
        IpFragOffset::try_new(IpFragOffset::MAX_U16 + 1),
        Err(ValueTooBigError{
            actual: IpFragOffset::MAX_U16 + 1,
            max_allowed: IpFragOffset::MAX_U16,
            value_type: ValueType::IpFragmentOffset,
        })
    );
}
```

--------------------------------

### Get Mutable Reference to Last Element

Source: https://docs.rs/etherparse/latest/etherparse/struct.Ipv4Options.html

Use `last_mut` to safely get a mutable reference to the last element, returning `None` for empty slices. Allows in-place modification.

```rust
let x = &mut [0, 1, 2];

if let Some(last) = x.last_mut() {
    *last = 10;
}
assert_eq!(x, &[0, 1, 10]);

let y: &mut [i32] = &mut [];
assert_eq!(None, y.last_mut());
```

--------------------------------

### Split Off Slice Starting with Third Element (Mutable)

Source: https://docs.rs/etherparse/latest/etherparse/struct.Ipv4Options.html

Removes and returns a mutable reference to a subslice starting from the third element. The original mutable slice is updated to contain the preceding elements.

```rust
let mut slice: &mut [_] = &mut ['a', 'b', 'c', 'd'];
let mut tail = slice.split_off_mut(2..).unwrap();

assert_eq!(slice, &mut ['a', 'b']);
assert_eq!(tail, &mut ['c', 'd']);
```

--------------------------------

### Iterating over IPv4 Options Ranges

Source: https://docs.rs/etherparse/latest/etherparse/struct.Ipv4Options.html

Demonstrates iterating through the ranges of IPv4 options.

```rust
assert_eq!(iter.next(), Some(Range { start: 0, end: 0 }));
assert_eq!(iter.next(), Some(Range { start: 1, end: 3 }));
assert_eq!(iter.next(), Some(Range { start: 4, end: 4 }));
assert_eq!(iter.next(), Some(Range { start: 5, end: 6 }));
```

--------------------------------

### TryFrom<u16> for LinuxNonstandardEtherType

Source: https://docs.rs/etherparse/latest/etherparse/struct.LinuxNonstandardEtherType.html?search=Option%3CT%3E%2C+%28T+-%3E+U%29+-%3E+Option%3CU%3E

Allows attempting to convert a u16 into a LinuxNonstandardEtherType, returning an error if the conversion fails.

```APIDOC
## type Error = ()

The type returned in the event of a conversion error.
```

```APIDOC
## fn try_from(value: u16) -> Result<Self, Self::Error>

Performs the conversion.
```

--------------------------------

### Get Mutable First Chunk of Slice

Source: https://docs.rs/etherparse/latest/etherparse/struct.Ipv4Options.html

Use `first_chunk_mut` with a const generic `N` to get a mutable array reference to the first `N` elements. Returns `None` if the slice is too short.

```rust
let x = &mut [0, 1, 2];

if let Some(first) = x.first_chunk_mut::<2>() {
    first[0] = 5;
    first[1] = 4;
}
assert_eq!(x, &[5, 4, 2]);

assert_eq!(None, x.first_chunk_mut::<4>());
```

--------------------------------

### MtuOptionSlice Methods

Source: https://docs.rs/etherparse/latest/etherparse/icmpv6/struct.MtuOptionSlice.html?search=

Provides methods for interacting with the MtuOptionSlice, including getting its length, creating it from a byte slice, retrieving the option type, accessing raw bytes, and getting the MTU value.

```APIDOC
## MtuOptionSlice

etherparse::icmpv6

### Struct MtuOptionSlice

`pub struct MtuOptionSlice<'a>`

MTU option slice (RFC 4861, Section 4.6.4, type 5).

### Implementations

#### impl<'a> MtuOptionSlice<'a>

##### `pub const LEN: usize = 8`

Serialized MTU option length in bytes.

##### `pub fn from_slice(slice: &'a [u8]) -> Result<Self, NdpOptionReadError>`

Creates an `MtuOptionSlice` from a byte slice.

##### `pub const fn option_type(&self) -> NdpOptionType`

Returns the option type value (5).

##### `pub fn as_bytes(&self) -> &'a [u8]`

Returns the serialized option bytes.

##### `pub fn mtu(&self) -> u32`

Returns the MTU value carried by the option.
```

--------------------------------

### Ipv6FlowLabel Usage Examples

Source: https://docs.rs/etherparse/latest/etherparse/struct.Ipv6FlowLabel.html?search=

Demonstrates various ways to create and use the Ipv6FlowLabel struct, including conversion from u32, using try_new for safe creation, and new_unchecked for performance-critical scenarios where the value is guaranteed to be within limits.

```APIDOC
## Ipv6FlowLabel Struct Usage

The `Ipv6FlowLabel` struct represents the 20-bit unsigned integer Flow Label in an IPv6 header. It provides methods for safe creation and conversion.

### Creating and Converting Ipv6FlowLabel

#### Using `try_into()`
This method attempts to convert a `u32` into an `Ipv6FlowLabel`. It returns a `Result` which will be `Ok` if the value is within the 20-bit limit, and `Err` otherwise.

```rust
use etherparse::Ipv6FlowLabel;

let flow_label: Ipv6FlowLabel = 123.try_into().unwrap();
assert_eq!(flow_label.value(), 123);

let value: u32 = flow_label.into();
assert_eq!(123, value);
```

#### Using `try_new()`
This is a safe constructor that takes a `u32` value and returns a `Result`. It ensures the provided value does not exceed the maximum allowed for a 20-bit flow label.

```rust
use etherparse::Ipv6FlowLabel;
use etherparse::err::{ValueTooBigError, ValueType};

let flow_label = Ipv6FlowLabel::try_new(123).unwrap();
assert_eq!(flow_label.value(), 123);

// Example of an error case when the value is too large:
assert_eq!(
    Ipv6FlowLabel::try_new(Ipv6FlowLabel::MAX_U32 + 1),
    Err(ValueTooBigError{
        actual: Ipv6FlowLabel::MAX_U32 + 1,
        max_allowed: Ipv6FlowLabel::MAX_U32,
        value_type: ValueType::Ipv6FlowLabel,
    })
);
```

#### Using `new_unchecked()`
This is an `unsafe` constructor that bypasses the bounds check. It should only be used when you are certain that the provided `u32` value is within the valid 20-bit range (0 to `Ipv6FlowLabel::MAX_U32`).

```rust
use etherparse::Ipv6FlowLabel;

// Safety: Ensure the value is not greater than Ipv6FlowLabel::MAX_U32
let flow_label = unsafe {
    Ipv6FlowLabel::new_unchecked(123)
};
assert_eq!(flow_label.value(), 123);
```

### Constants

- `Ipv6FlowLabel::MAX_U32`: The maximum value a 20-bit flow label can hold.
```

--------------------------------

### Get Mutable Slice to Array

Source: https://docs.rs/etherparse/latest/etherparse/struct.Ipv4Options.html

Attempts to get a mutable reference to the slice’s underlying array if the requested size `N` exactly matches the slice length. Returns `None` otherwise.

```Rust
let mut slice = [1, 2, 3];
let array: Option<&mut [i32; 3]> = slice.as_mut_array();
if let Some(arr) = array {
    arr[0] = 10;
}
assert_eq!(slice[0], 10);
```

--------------------------------

### Example Searches for LaxPayloadSlice

Source: https://docs.rs/etherparse/latest/etherparse/enum.LaxPayloadSlice.html?search=

Demonstrates various ways to search within LaxPayloadSlice, including searching for specific types, type conversions, and generic type manipulations.

```APIDOC
## Example Searches

### Search for a specific type
```
std::vec
```

### Search for type conversion
```
u32 -> bool
```

### Search for generic type conversion with Option
```
Option<T>, (T -> U) -> Option<U>
```
```

--------------------------------

### Example: Parsing PacketHeaders from IP Slice

Source: https://docs.rs/etherparse/latest/etherparse/struct.PacketHeaders.html?search=std%3A%3Avec

Illustrates how to use PacketHeaders::from_ip_slice to decode an IP packet and its transport headers, assuming the input slice begins with the IP header. Displays how to inspect the parsed header fields.

```rust
use etherparse::PacketHeaders;

match PacketHeaders::from_ip_slice(&packet) {
    Err(value) => println!("Err {:?}", value),
    Ok(value) => {
        println!("link: {:?}", value.link);
        println!("link_exts: {:?}", value.link_exts); // vlan & macsec
        println!("net: {:?}", value.net); // ip & arp
        println!("transport: {:?}", value.transport);
    }
}

```