SignOn & Packet

Packets contain simulated information about a session. A SignOn message is the same as a Packet message but only appears once at the very beginning to indicate that the server is ready.

Overview

Name	Type	Size in bytes	Size in bits	Value
PacketInfo	byte[]	76*MSSC	76*MSSC*8	CmdInfo[]
InSequence	int	4	32	-
OutSequence	int	4	32	-
Size	int	4	32	-
Data	byte[]	Size	Size*8	NetSvcMessage[]

C

typedef struct {
    char* packet_info;
    int in_sequence;
    int out_sequence;
    int size;
    char* data;
} packet_t;

C++

struct packet_t {
    std::vector<std::byte> packet_info;
    int32_t in_sequence;
    int32_t out_sequence;
    int32_t size;
    std::vector<std::byte> data;
};

C#

class Packet {
    public List<byte> PacketInfo { get; set; }
    public int InSequence { get; set; }
    public int OutSequence { get; set; }
    public int Size { get; set; }
    public List<byte> Data { get; set; }
}

JS

class Packet {
  /** @type {number[]} */
  packetInfo;
  /** @type {number} */
  inSequence;
  /** @type {number} */
  outSequence;
  /** @type {number} */
  size;
  /** @type {number[]} */
  data;
}

TS

export class Packet {
  public packetInfo?: number[];
  public inSequence?: number;
  public outSequence?: number;
  public size?: number;
  public data?: number[];
}

Go

type Packet struct {
	PacketInfo  []byte
	InSequence  int32
	OutSequence int32
	Size        int32
	Data        []byte
}

Rust

pub struct Packet {
    pub packet_info: Vec<u8>,
    pub in_sequence: i32,
    pub out_sequence: i32,
    pub size: i32,
    pub data: Vec<u8>,
}

Zig

const Packet = struct {
    packet_info: []u8,
    in_sequence: i32,
    out_sequence: i32,
    size: i32,
    data: []u8,
};

MaxSplitScreenClients (MSSC)

This value is most likely 1 for single-player-only games but 2 for multiplayer games which support split screen mode (Portal 2, CS:GO etc.). Although it can be misleading if a game does not have multiplayer mode but yet supports this feature. The console command maxplayers can be executed in the developer console and should help to find out the exact value for a specific game.