smoltcp/src/wire/mod.rs

/*! Low-level packet access and construction.

The `wire` module deals with the packet *representation*. It provides two levels
of functionality.

 * First, it provides functions to extract fields from sequences of octets,
   and to insert fields into sequences of octets. This happens `Packet` family of
   structures, e.g. [EthernetFrame] or [Ipv4Packet].
 * Second, in cases where the space of valid field values is much smaller than the space
   of possible field values, it provides a compact, high-level representation
   of packet data that can be parsed from and emitted into a sequence of octets.
   This happens through the `Repr` family of structs and enums, e.g. [ArpRepr] or [Ipv4Repr].

[EthernetFrame]: struct.EthernetFrame.html
[Ipv4Packet]: struct.Ipv4Packet.html
[ArpRepr]: enum.ArpRepr.html
[Ipv4Repr]: struct.Ipv4Repr.html

The functions in the `wire` module are designed for use together with `-Cpanic=abort`.

The `Packet` family of data structures guarantees that, if the `Packet::check_len()` method
returned `Ok(())`, then no accessor or setter method will panic; however, the guarantee
provided by `Packet::check_len()` may no longer hold after changing certain fields,
which are listed in the documentation for the specific packet.

The `Packet::new_checked` method is a shorthand for a combination of `Packet::new` and
`Packet::check_len`.
When parsing untrusted input, it is *necessary* to use `Packet::new_checked()`;
so long as the buffer is not modified, no accessor will fail.
When emitting output, though, it is *incorrect* to use `Packet::new_checked()`;
the length check is likely to succeed on a zeroed buffer, but fail on a buffer
filled with data from a previous packet, such as when reusing buffers, resulting
in nondeterministic panics with some network devices but not others.
The buffer length for emission is not calculated by the `Packet` layer.

In the `Repr` family of data structures, the `Repr::parse()` method never panics
as long as `Packet::new_checked()` (or `Packet::check_len()`) has succeeded, and
the `Repr::emit()` method never panics as long as the underlying buffer is exactly
`Repr::buffer_len()` octets long.

# Examples

To emit an IP packet header into an octet buffer, and then parse it back:

```rust
# #[cfg(feature = "proto-ipv4")]
# {
use smoltcp::phy::ChecksumCapabilities;
use smoltcp::wire::*;
let repr = Ipv4Repr {
    src_addr:    Ipv4Address::new(10, 0, 0, 1),
    dst_addr:    Ipv4Address::new(10, 0, 0, 2),
    protocol:    IpProtocol::Tcp,
    payload_len: 10,
    hop_limit:   64
};
let mut buffer = vec![0; repr.buffer_len() + repr.payload_len];
{ // emission
    let mut packet = Ipv4Packet::new(&mut buffer);
    repr.emit(&mut packet, &ChecksumCapabilities::default());
}
{ // parsing
    let packet = Ipv4Packet::new_checked(&buffer)
                            .expect("truncated packet");
    let parsed = Ipv4Repr::parse(&packet, &ChecksumCapabilities::default())
                          .expect("malformed packet");
    assert_eq!(repr, parsed);
}
# }
```
*/

mod field {
    pub type Field = ::core::ops::Range<usize>;
    pub type Rest  = ::core::ops::RangeFrom<usize>;
}

pub mod pretty_print;

mod ethernet;
#[cfg(feature = "proto-ipv4")]
mod arp;
pub(crate) mod ip;
#[cfg(feature = "proto-ipv4")]
mod ipv4;
#[cfg(feature = "proto-ipv6")]
mod ipv6;
#[cfg(feature = "proto-ipv4")]
mod icmpv4;
#[cfg(feature = "proto-ipv6")]
mod icmpv6;
mod udp;
mod tcp;

pub use self::pretty_print::PrettyPrinter;

pub use self::ethernet::{EtherType as EthernetProtocol,
                         Address as EthernetAddress,
                         Frame as EthernetFrame};

#[cfg(feature = "proto-ipv4")]
pub use self::arp::{Hardware as ArpHardware,
                    Operation as ArpOperation,
                    Packet as ArpPacket,
                    Repr as ArpRepr};

pub use self::ip::{Version as IpVersion,
                   Protocol as IpProtocol,
                   Address as IpAddress,
                   Endpoint as IpEndpoint,
                   Repr as IpRepr,
                   Cidr as IpCidr};

#[cfg(feature = "proto-ipv4")]
pub use self::ipv4::{Address as Ipv4Address,
                     Packet as Ipv4Packet,
                     Repr as Ipv4Repr,
                     Cidr as Ipv4Cidr,
                     MIN_MTU as IPV4_MIN_MTU};

#[cfg(feature = "proto-ipv6")]
pub use self::ipv6::{Address as Ipv6Address,
                     Packet as Ipv6Packet,
                     Repr as Ipv6Repr,
                     Cidr as Ipv6Cidr,
                     MIN_MTU as IPV6_MIN_MTU};

#[cfg(feature = "proto-ipv4")]
pub use self::icmpv4::{Message as Icmpv4Message,
                       DstUnreachable as Icmpv4DstUnreachable,
                       Redirect as Icmpv4Redirect,
                       TimeExceeded as Icmpv4TimeExceeded,
                       ParamProblem as Icmpv4ParamProblem,
                       Packet as Icmpv4Packet,
                       Repr as Icmpv4Repr};

#[cfg(feature = "proto-ipv6")]
pub use self::icmpv6::{Message as Icmpv6Message,
                       DstUnreachable as Icmpv6DstUnreachable,
                       Packet as Icmpv6Packet,
                       Repr as Icmpv6Repr};

pub use self::udp::{Packet as UdpPacket,
                    Repr as UdpRepr};

pub use self::tcp::{SeqNumber as TcpSeqNumber,
                    Packet as TcpPacket,
                    TcpOption,
                    Repr as TcpRepr,
                    Control as TcpControl};