Add IS_IPB packet and TINY_IPB subtype of IS_TINY

[mkapal]

A new IS_IPB packet was introduced in LFS version 0.7F.

Source code from InSim.txt:

// IP Bans

// You can set up to 120 IP addresses that are not allowed to join a host

const int IPB_MAX_BANS = 120;

struct IS_IPB // IP Bans - variable size
{
	byte	Size;		// 8 + NumB * 4
	byte	Type;		// ISP_IPB
	byte	ReqI;		// 0 unless this is a reply to a TINY_IPB request
	byte	NumB;		// number of bans in this packet

	byte	Sp0;
	byte	Sp1;
	byte	Sp2;
	byte	Sp3;

	in_addr		BanIPs	[MAL_MAX_MODS]; // IP addresses, 0 to IPB_MAX_BANS (NumB)
};

Also the IS_TINY enum has been updated with a new subtype added at the end:

TINY_IPB,		// 29 - info request	: send IS_IPB listing the IP bans

IP address handling

As of now, the only use case of handling IP addresses is in the IS_NCI packet:

node-insim/src/packets/IS_NCI.ts

Lines 31 to 32 in f81c75c

	/** IP address formatted as 255.255.255.255 */
	@unsigned() IPAddress = '';

When the packet is received, the IP address is converted into a string:

node-insim/src/packets/IS_NCI.ts

Line 37 in f81c75c

this.IPAddress = buffer.slice(12, 16).join('.');

Should it be handled the same in the new IS_IPB packet, or should all IP address fields be stored as a utility object, allowing the users to convert the IP address from/to bytes, perform validations and other useful operations?

Here are my proposed options:

Plain string

When a packet is received, the binary 4-byte integer is converted into string containing 4 numbers separated by dots.

When a packet is sent, the IP string is parsed and converted into the 4-byte integer.

• easy to use
• app developers must use additional tools to convert the provided IP string into different formats

// Sending a packet
inSim.send(new IS_IPB({
  NumB: 2,
  BanIPs: ['1.2.3.4', '5.6.7.8'],
}));

// Receiving a packet
inSim.on(PacketType.ISP_IPB, (packet) => {
  console.log(packet.BanIPs[0]); // '1.2.3.4'
});

Utility object

Make use of a library capable of converting an IP address between integer, hexadecimal, string etc. and able to parse and validate an input IP.

• need to wrap each IP into a class constructor

// Sending a packet
inSim.send(new IS_IPB({
  NumB: 2,
  BanIPs: [new Address4('1.2.3.4'), new Address4('5.6.7.8')],
}));

// Sending an invalid IP
inSim.send(new IS_IPB({
  NumB: 2,
  BanIPs: [new Address4('455.34.56788.23')],
})); // -> Throws a runtime validation error

// Receiving a packet
inSim.on(PacketType.ISP_IPB, (packet) => {
  // string representation
  console.log(packet.BanIPs[0].address); // '1.2.3.4'

  // byte array
  console.log(packet.BanIPs[0].toArray()); // [1,2,3,4]
});

Examples of such libraries:

https://github.com/indutny/node-ip
https://github.com/beaugunderson/ip-address

[mkapal]

I have decided to do start simple and only work with strings on the consumer side. Also, I have added validation when sending a range of IPs. If some of the IPs don't conform to the IPv4 format, a RangeError will be thrown. See #48

[github-actions]

🎉 This issue has been resolved in version 4.2.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

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