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README.md
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@ -1,3 +1,50 @@
# natpmpcrystal
# natpmp-crystal
Work in progress library implementation of RFC6886 **NAT Port Mapping Protocol (NAT-PMP)**
Work in progress implementation of RFC 6886 **NAT Port Mapping Protocol (NAT-PMP)**, client side.
Since RFC 6886 is a pretty simple protocol, it should be ready to use to requests mappings
## Installation
1. Add the dependency to your `shard.yml`:
```yaml
dependencies:
natpmp-crystal:
github: fijxu/natpmp-crystal
```
2. Run `shards install`
## Usage
```crystal
# Create NAT-PMP client, replace the IP by the IP of your
# gateway
client = NatPMP::Client.new("192.168.1.1")
# Public address request
client.send_public_address_request # => {0, 128, 0, 22758, "104.0.0.0"}
client.send_public_address_request_as_bytes # => Bytes[0, 128, 0, 0, 0, 0, 88, 230, 104, 0, 0, 0]
# Maps the internal port 25565 to external port 25565, TCP
client.request_mapping(25565, 25565, 2) # => {0, 130, 0, 22758, 25565, 25565, 7200}
# Destroys the mapping with internal port 25565, TCP
client.destroy_mapping(25565, 2) # => {0, 130, 0, 22758, 25565, 0, 0}
# Maps the internal port 22000 to external port 22000, UDP
client.request_mapping(22000, 22000, 1) # => {0, 129, 0, 22758, 22000, 22000, 7200}
# Destroys the mapping with internal port 22000, UDP
client.destroy_mapping(22000, 1) # => {0, 129, 0, 22758, 22000, 0, 0}
```
## Contributing
1. Fork it (<https://github.com/fijxu/natpmp-crystal/fork>)
2. Create your feature branch (`git checkout -b my-new-feature`)
3. Commit your changes (`git commit -am 'Add some feature'`)
4. Push to the branch (`git push origin my-new-feature`)
5. Create a new Pull Request
## Contributors
- [Fijxu](https://github.com/fijxu) - creator and maintainer

2
shard.yml
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@ -1,5 +1,5 @@
name: natpmp-crystal
version: 0.1.0
version: 0.1.1
authors:
- Fijxu <fijxu@nadeko.net>

143
src/natpmp.cr
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@ -2,6 +2,9 @@ require "socket"
require "benchmark"
module NatPMP
# Result codes defined by the RFC 6886
#
# [RFC 6886 - 3.5. Result Codes](https://datatracker.ietf.org/doc/html/rfc6886#section-3.5)
enum ResultCodes
SUCCESS = 0
UNSUPPORTED_VERSION = 1
@ -11,18 +14,38 @@ module NatPMP
UNSUPPORTED_OPCODE = 5
end
# Opcodes defined by the RFC 6886
#
# *"Otherwise, if the opcode in the request is less than 128, but is not a supported opcode **(currently 0, 1, or 2)**"*
#
# [RFC 6886 - 3.5. Result Codes](https://datatracker.ietf.org/doc/html/rfc6886#section-3.5)
enum OP : UInt8
NOOP = 0_u8
UDP = 1_u8
TCP = 2_u8
end
# You can use this struct to craft your own mapping packets in case you want
# to handle it all by yourself.
#
# ```
# # This creates a mapping that you can use to send trough a Socket
# packet_io = NatPMP::MappingPacket.new(25565, 25565, 1, 3600).to_io
# packet_slice = NatPMP::MappingPacket.new(25565, 25565, 1, 3600).to_slice
# ```
struct MappingPacket
@vers : UInt8 = 0_u8
@op : UInt8
@reserved : UInt16 = 0_u16
@internal_port : UInt16
@external_port : UInt16
@lifetime : UInt32 = 0_u32
@lifetime : UInt32
def initialize(@internal_port, @external_port, @lifetime = 7200, @op = 1)
def initialize(@internal_port, @external_port, @op = 1, @lifetime = 7200)
raise ArgumentError.new("operation should be either 1_u8 for UDP or 2_u8 for TCP") if ![1, 2].includes?(@op)
end
# Converts the struct instance variables to IO.
def to_io
io = IO::Memory.new(12)
io.write_bytes(@vers, IO::ByteFormat::BigEndian)
@ -31,12 +54,14 @@ module NatPMP
io.write_bytes(@internal_port, IO::ByteFormat::BigEndian)
io.write_bytes(@external_port, IO::ByteFormat::BigEndian)
io.write_bytes(@lifetime, IO::ByteFormat::BigEndian)
return io
io
end
# Converts the struct instance variables to an StaticArray.
#
# Side Note: This is not actually a Slice, it's an StaticArray so I don't
# think this member function should be called like this.
def to_slice
# This is not actually a Slice, it's an StaticArray so I don't
# think this member function should be called like this.
slice = uninitialized UInt8[12]
IO::ByteFormat::BigEndian.encode(@op, o = Bytes.new(1))
IO::ByteFormat::BigEndian.encode(@internal_port, i = Bytes.new(2))
@ -54,7 +79,7 @@ module NatPMP
slice[9] = l[1]
slice[10] = l[2]
slice[11] = l[3]
return slice
slice
end
end
@ -62,44 +87,39 @@ module NatPMP
@socket : UDPSocket
@gateway_ip : String
# Overload
def initialize(gateway_ip : URI)
initialize(gateway_ip.path)
def initialize(gateway_ip : URI, autoconnect : Bool = true)
initialize(gateway_ip.path, autoconnect)
end
# Creates a new NAT-PMP Client, it's only able to connect trough IPV4 so
# if you supply a IPV6 address, it will fail;
# By default, it connects automatically to the NAT-PMP server, you can
# change this by setting `autoconnect` to false like this:
# `client = NatPMP::Client.new("192.168.1.1", false)`, that way, you can
# change the socket properties like `client.@socket.bind` to your liking
# before connecting.
#
# ```
# client = NatPMP::Client.new("192.168.1.1")
# ```
def initialize(@gateway_ip : String, autoconnect : Bool = true)
# The specification is IPV4 only!
@socket = UDPSocket.new(Socket::Family::INET)
# A given host may have more than one independent
# NAT-PMP client running at the same time, and address announcements
# need to be available to all of them. Clients should therefore set
# the SO_REUSEPORT option or equivalent in order to allow other
# processes to also listen on port 5350.
@socket.reuse_port = true
@socket.reuse_address = true
# Additionally, implementers
# have encountered issues when one or more processes on the same device
# listen to port 5350 on *all* addresses. Clients should therefore
# bind specifically to 224.0.0.1:5350, not to 0.0.0.0:5350.
@socket.bind 5350
if autoconnect
connect()
end
end
def connect
# @socket.join_group(Socket::IPAddress.new("224.0.0.1", 5351))
# Connects to the NAT-PMP server, you don't need to call this function
# unless you have setted `autoconnect` is false on the constructor.
def connect : Nil
@socket.connect(@gateway_ip, 5351)
end
def send_public_address_request_raw : Bytes
@socket.send("\x00\x00")
msg = Bytes.new(12)
@socket.receive(msg)
return msg
end
def send_public_address_request
private def send_external_address_request_ : Bytes
@socket.send("\x00\x00")
msg = Bytes.new(12)
@socket.read_timeout = 250.milliseconds
@ -109,11 +129,6 @@ module NatPMP
@socket.receive(msg)
break
rescue IO::TimeoutError
# If no
# NAT-PMP response is received from the gateway after 250 ms, the
# client retransmits its request and waits 500 ms. The client SHOULD
# repeat this process with the interval between attempts doubling each
# time.
@socket.read_timeout = @socket.read_timeout.not_nil!*2
next
rescue
@ -122,14 +137,37 @@ module NatPMP
end
end
msg
end
# Returns the external address response as a `Slice(UInt8)`
#
# ```
# client.send_external_address_request_as_bytes # => Bytes[0, 128, 0, 0, 0, 0, 88, 230, 104, 0, 0, 0]
# ```
def send_external_address_request_as_bytes : Bytes
msg = send_external_address_request_
msg
end
# Returns the external address response as a `Tuple(UInt8, UInt8, UInt16, UInt32, String | Nil)`
#
# ```
# res = client.send_external_address_request # => {0, 128, 0, 177060, "104.0.0.0"}
# version = res[0]
# operation = res[1]
# result_code = res[2]
# epoch = res[3]
# external_address = res[4]
# ```
def send_external_address_request : Tuple(UInt8, UInt8, UInt16, UInt32, String | Nil)
msg = send_external_address_request_
vers : UInt8 = msg[0]
op : UInt8 = msg[1]
result_code = decode_msg(UInt16, msg[2..3])
epoch = decode_msg(UInt32, msg[4..7])
# If the result code is non-zero, the value of the External
# IPv4 Address field is undefined (MUST be set to zero on transmission,
# and MUST be ignored on reception).
if result_code != 0
ip_address = nil
else
@ -138,8 +176,23 @@ module NatPMP
return vers, op, result_code, epoch, ip_address
end
def request_mapping(internal_port : UInt16, external_port : UInt16, operation : UInt8, lifetime : UInt32 = 7200)
request = MappingPacket.new(internal_port, external_port, lifetime, operation).to_slice
# Requests a mapping to the NAT-PMP server
#
# More details about how requesting a mapping works here: [RFC 6886 - 3.3. Requesting a Mapping](https://datatracker.ietf.org/doc/html/rfc6886#section-3.3)
# ```
# # Maps the internal port 25565 to external port 25565, TCP, with a lifetime
# # of 7200 seconds (the default defined by the RFC)
# client.request_mapping(25565, 25565, 2) # => {0, 130, 0, 22758, 25565, 25565, 7200}
# # The same as above, but with a lifetime of 60 seconds
# client.request_mapping(25565, 25565, 2, 60) # => {0, 130, 0, 22758, 25565, 25565, 60}
# # Maps the internal port 25565 to external port 25565, UDP, with a lifetime
# # of 7200 seconds (the default defined by the RFC)
# client.request_mapping(25565, 25565, 1) # => {0, 129, 0, 22758, 25565, 25565, 7200}
# # The same as above, but with a lifetime of 60 seconds
# client.request_mapping(25565, 25565, 1, 60) # => {0, 129, 0, 22758, 25565, 25565, 60}
# ```
def request_mapping(internal_port : UInt16, external_port : UInt16, operation : UInt8, lifetime : UInt32 = 7200) : Tuple(UInt8, UInt8, UInt16, UInt32, UInt16, UInt16, UInt32)
request = MappingPacket.new(internal_port, external_port, operation, lifetime).to_slice
msg = Bytes.new(16)
@socket.send(request)
@socket.receive(msg)
@ -155,9 +208,17 @@ module NatPMP
return vers, op, result_code, epoch, internal_port, external_port, lifetime
end
# https://datatracker.ietf.org/doc/html/rfc6886#section-3.4
def destroy_mapping(internal_port : UInt16, operation : UInt8)
request = MappingPacket.new(internal_port, 0, 0, operation).to_slice
# Destroys a mapping in the NAT-PMP server
#
# More details about how destroying a mapping works here: [RFC 6886 - 3.4. Destoying a Mapping](https://datatracker.ietf.org/doc/html/rfc6886#section-3.4)
# ```
# # Destroys the mapping with internal port 25565, TCP
# client.destroy_mapping(25565, 2) # => {0, 130, 0, 22758, 25565, 0, 0}
# # Destroys the mapping with internal port 25565, UDP
# client.destroy_mapping(25565, 1) # => {0, 130, 0, 22758, 25565, 0, 0}
# ```
def destroy_mapping(internal_port : UInt16, operation : UInt8) : Tuple(UInt8, UInt8, UInt16, UInt32, UInt16, UInt16, UInt32)
request = MappingPacket.new(internal_port, 0, operation, 0).to_slice
msg = Bytes.new(16)
@socket.send(request)
@socket.receive(msg)