Initial work on PingManager

docs/README.md

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+# Documentation
+
+## File Formats
+
+Documentation and examples of file formats.
+
+### [Legacy Manifest](file_formats/LEGACY_MANIFEST.md)
+
+Blue Hell Productions `manifest.xml`. Still in use by W3D Hub.
+
+### [Megafest](file_formats/MEGAFEST.md)
+
+Prototype new thing `megafest.json`
+
+### [MIX](file_formats/MIX.md)
+
+Westwood archive format `<name>.mix`, `<name>.dat` and `<name>.pkg`
+
+### [W3D Hub Patch](file_formats/W3D_HUB_PATCH.md)
+
+Describes how to update a MIX archive from a package patch
+
+## Protocols
+
+### [LAN Discovery](protocols/LAN_DISCOVERY.md)
+
+How launchers and other applications discovery each other.
+
+### [Launcher Remote](protocols/LAUNCHER_REMOTE.md)
+
+Remotely control and get progress reports from the launcher
+
+### [LAN Package Share](protocols/LAN_PACKAGE_SHARE.md)
+
+Enable launchers on the same network to discover each other and share packages over LAN.

docs/file_formats/LEGACY_MANIFEST.md

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+# Legacy Manifest
+
+In use since Blue Hell Productions
+
+> [!IMPORTANT]
+> References to packages exclude `.zip`
+
+Example `Full` manifest:
+
+```xml
+
+<BHP_Game_Manifest game="apb" version="0.9935.1.0" type="Full">
+    <Dependency name="msvc-2015.zip"/>
+    <Dependency name="directx-43.zip"/>
+    <File name="game.exe" checksum="C7AE972A2B9CF6EFCADE7919323F048F5CFAF2D40BD5A67D5A91F8D8A3759CA4" package="binaries"/>
+    <File name="MemoryManager.dll" checksum="B60A2B3F6A07D729EE5C2902CB9A6BEDAF55EEDB13F8514BAC0AD6F5D51DD0C2" package="binaries"/>
+    <File name="scripts.dll" checksum="76CAAEBF21E4D6A34C3ABDD474D59580DD1EAB097C9585A1FFC0E28FF0FCAF56" package="binaries"/>
+    <File name="Scripts2.dll" checksum="A0439B3BFE6CB497F402291548A312A9F43C0D38BDAF26C83E21DBD3F4D55702" package="binaries"/>
+    <File name="shared.dll" checksum="17A8797EC5F4C34E241681F4AF76EEA93856D6A1854EC9838B263AEC89CDF036" package="binaries"/>
+    <File name="ttle.dll" checksum="C005EB50D77675CE712B30A4402AB0D152D3993EB509E35AEDCB834CED54FADF" package="binaries"/>
+    <File name="ttversion.txt" checksum="17A9E627A03E20AC33849330468BF8A80B48449C9D473DF45F1052A160083167" package="misc"/>
+    <File name="Data/always.dat" checksum="D4D09149C7B5368AB3947AEC7B6E7781208F592FCA4390261F04A8E9C1887EB3" package="always"/>
+    <File name="Data/RA_Volcano.mix" checksum="4F3CB80BCF200659B3B4B167CCB64ECB36A3BA917681F4AB8027568EC187B88D" package="RA_Volcano"/>
+    <File name="Data/Movies/ea_ww.bik" checksum="065B8B0894CF9C1C09A940D26069C54A771EBB3092143BA37E97F8CA85B8CCAD" package="movies"/>
+    <File name="Data/Movies/R_Intro.BIK" checksum="0D9A2B2ABFD9680DF1C8D0F876DA4B60F015CA5C56EC6C0593528A3F88E2A58F" package="movies"/>
+</BHP_Game_Manifest>
+```
+
+Example `Patch` manifest:
+
+```xml
+
+<BHP_Game_Manifest game="apb" version="3.6.4.1" type="Patch" baseVersion="3.6.4.0">
+    <Dependency name="msvc-2022.zip"/>
+    <Dependency name="msvc-2015.zip" removedsince="3.6.4.1"/>
+    <File name="data/Always.dat" checksum="7B27D547E5A50401C9CA2851ACD4AC3F3CDA104F34650E1C32EB63A4120E3C90">
+        <Patch from="3.6.4.0" package="Always.patch.3.6.4.0"/>
+    </File>
+    <File name="data/Always_Emitters.dat" checksum="5C3EA8E5C4D7278F5EF1AF3CE1FC4F698C5A7D1FE7116DA0376A709E7CD3B2AE">
+        <Patch from="3.6.3.0" package="Always_Emitters.patch.3.6.3.0"/>
+    </File>
+    <File name="data/Always_Vehicles.dat" checksum="C6D4F6B3412C26065DE9B9F739BEC041B49FD613DB2686D8F231C2F692B263C5">
+        <Patch from="3.6.4.0" package="Always_Vehicles.patch.3.6.4.0"/>
+    </File>
+    <File name="data/RA_TestUnits.mix" removedsince="3.6.4.1"/>
+    <File name="data/RA_RidgeWar.mix" checksum="C3438C532C27F535CD958BEA9702160E952BC6CE58F9B43778F91DA23C6AE9FE" package="RA_RidgeWar"/>
+    <File name="data/RA_SwampOfIllusions.mix" checksum="A0787979664E5977A1949587382A3A84B9F1526F81934EBB7A3AC9334F9D4059">
+        <Patch from="3.6.4.0" package="RA_SwampOfIllusions.patch.3.6.4.0"/>
+    </File>
+</BHP_Game_Manifest>
+```
+
+## SPECIFICATION
+### BHP_GAME_MANIFEST (Root Element)
+* **GAME** - Unique Application ID
+* **VERSION** - Application Unique Version for Build
+* **TYPE** - Type of Build
+  * **Full** - Full Build
+  * **Patch** - Patch Build
+* **BASEVERSION** - *OPTIONAL* Version this build was based upon 
+
+### DEPENDENCY
+* **NAME** - Package name of dependency sans file extension
+* **REMOVEDSINCE** - _OPTIONAL_ No data. Not used anymore?
+
+### FILE
+* **NAME** - Name of file
+* **CHECKSUM** - _OPTIONAL_ SHA256 hash of file
+* **PACKAGE** - _OPTIONAL_ Package that contains this file. Not present on removed files or files that have been patched.
+* **REMOVEDSINCE** - _OPTIONAL_ Version this package was removed in. If present, only _NAME_ and _REMOVEDSINCE_ will be present.
+  * **PATCH**
+    * **FROM** - Version that the file last changed
+    * **PACKAGE** - Name of package that contains this file.

docs/file_formats/MEGAFEST.md

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+> [!NOTE]
+> DRAFT
+
+# Megafest
+
+The fat manifest for W3D Hub Packager and Launcher(s), represented as a JSON hash.
+
+This **MEGAFEST** is intended to simplify patch generation and distribution by ensuring that
+all the data the Packager and Launcher(s) need can be found in a **single** manifest file.
+
+Speed up application packaging by only needing to scan and checksum the new builds files instead of needing
+to maintain a pristine copy of the previous version to be diffed against.
+
+Reduce the number of requests that the launcher(s) need to make to sort out how to download and
+patch the application.
+
+## Glossary
+
+### File
+
+An individual file on disk.
+
+An individual file as part of a MIX archive.
+
+### Package
+
+A collection of one or more files in a compressed archive for efficiently distributing the application.
+
+> [!NOTE]
+> Packages _MAY_ be compressed using ZSTANDARD (.zst) in the future. Do not assume all packages are zip files.
+>
+> Package names in the megafest include the file extension for this reason. 
+
+## Example `megafest.json` File
+
+```json
+{
+  "spec": 0,
+  "application": {
+    "id": "apb",
+    "version": "3.7.0.1",
+    "user_level": "public",
+    "previous_versions": [
+      "3.7.0.0"
+    ]
+  },
+  "dependencies": [
+    "msvc-2022"
+  ],
+  "packages": [
+    {
+      "name": "binaries.zip",
+      "version": "3.7.0.0",
+      "checksum": "SHA256-HASH",
+      "size": 4096,
+      "chunk_size": 4194304,
+      "chunk_checksums": [
+        "SHA256-HASH-A",
+        "SHA256-HASH-B"
+      ],
+      "files": [
+        {
+          "name": "game2.exe",
+          "checksum": "SHA256-HASH",
+          "size": 8691743
+        }
+      ]
+    },
+    {
+      "name": "data/Always.dat.zip",
+      "version": "3.7.0.0",
+      "checksum": "SHA256-HASH",
+      "size": 1355917483,
+      "chunk_size": 4194304,
+      "chunk_checksums": [
+        "SHA256-HASH-A",
+        "SHA256-HASH-B"
+      ],
+      "files": [
+        {
+          "name": "mp_wep_gdi.w3d",
+          "checksum": "CRC32-HASH",
+          "offset": 0,
+          "size": 8691743
+        }
+      ]
+    },
+    {
+      "name": "data/Always.patch.3.7.0.0.zst",
+      "version": "3.7.0.1",
+      "checksum": "SHA256-HASH",
+      "size": 1355919483,
+      "chunk_size": 4194304,
+      "chunk_checksums": [
+        "SHA256-HASH-A",
+        "SHA256-HASH-B"
+      ],
+      "from_version": "3.7.0.0",
+      "files": [
+        {
+          "name": "data/Always.patch",
+          "checksum": "SHA256-HASH",
+          "size": 8691743
+        }
+      ]
+    },
+    {
+      "name": "binaries.zip",
+      "version": "3.7.0.1",
+      "checksum": "SHA256-HASH",
+      "size": 4096,
+      "chunk_size": 4194304,
+      "chunk_checksums": [
+        "SHA256-HASH-A",
+        "SHA256-HASH-B"
+      ],
+      "files": [
+        {
+          "name": "game.exe",
+          "checksum": "SHA256-HASH",
+          "size": 8691743
+        }
+      ]
+    }
+  ],
+  "changes": [
+    {
+      "name": "game.exe",
+      "type": "added",
+      "package": "binaries"
+    },
+    {
+      "name": "game2.exe",
+      "type": "removed"
+    },
+    {
+      "name": "data/Always.dat",
+      "type": "updated",
+      "package": "Always.dat"
+    }
+  ],
+  "index": [
+    {
+      "name": "game.exe",
+      "checksum": "SHA256-HASH",
+      "size": 8691743
+    },
+    {
+      "name": "data/Always.dat",
+      "checksum": "SHA256-HASH",
+      "size": 1355917483
+    }
+  ]
+}
+```
+
+## SPECIFICATION
+
+### Application
+
+List of application details:
+
+* **ID** - Unique Application ID
+* **VERSION** - Application Unique Version
+* **USER_LEVEL** - User access level for this version
+* **PREVIOUS_VERSIONS** - Complete list of previous versions. Full builds only include _the_ previous version
+
+Example:
+
+```json
+{
+  "id": "apb",
+  "version": "3.7.0.1",
+  "user_level": "public",
+  "previous_versions": [
+    "3.7.0.0"
+  ]
+}
+```
+
+### Dependencies
+
+List of application's dependencies
+
+Example:
+
+```json
+[
+  "msvc-2022"
+]
+```
+
+### Packages
+
+Complete list of application's version tree of packages.
+
+That is, every package from the last full build to present for this version series.
+
+* **NAME** - Name of package
+* **VERSION** - Application version this package belongs to
+* **CHECKSUM** - SHA256 checksum of package
+* **SIZE** - File size of package in bytes
+* CHUNK **SIZE** - Size _CHUNK_CHECKSUMS_ represent in bytes
+* **CHUNK_CHECKSUMS** - Array of file chunk checksums
+* **FROM_VERSION** - *OPTIONAL* Version this file was last changed. Only present for MIX patches.
+* **FILES** - Array of files
+    * **NAME**
+    * **CHECKSUM** - SHA256 checksum of file.
+    * **SIZE** - File size in bytes
+
+Example:
+
+```json
+[
+  {
+    "name": "binaries",
+    "version": "3.7.0.0",
+    "checksum": "SHA256-HASH",
+    "size": 4096,
+    "chunk_size": 4194304,
+    "chunk_checksums": [
+      "SHA256-HASH-A",
+      "SHA256-HASH-B"
+    ],
+    "files": [
+      {
+        "name": "game.exe",
+        "checksum": "SHA256-HASH",
+        "size": 8691743
+      }
+    ]
+  },
+  {
+    "name": "data/Always.patch.3.7.0.0",
+    "version": "3.7.0.1",
+    "checksum": "SHA256-HASH",
+    "size": 2436543,
+    "chunk_size": 4194304,
+    "chunk_checksums": [
+      "SHA256-HASH-A",
+      "SHA256-HASH-B"
+    ],
+    "from_version": "3.7.0.0",
+    "files": [
+      {
+        "name": "data/Always.patch",
+        "checksum": "SHA256-HASH",
+        "size": 3636749
+      }
+    ]
+  }
+]
+```
+
+### Changes
+
+List of file changes in this build.
+
+* **NAME** - Name of file
+* **TYPE** - Type of change
+    * **ADDED** - New file has been added
+    * **UPDATED** - File has been changed
+    * **REMOVED** - File has been deleted
+* **PACKAGE** - _OPTIONAL_ Name of package, for this build version, the file can be found in
+
+```json
+[
+  {
+    "name": "game.exe",
+    "type": "updated",
+    "package": "binaries.zip"
+  },
+  {
+    "name": "game2.exe",
+    "type": "removed"
+  },
+  {
+    "name": "data/Always.dat",
+    "type": "added",
+    "package": "Always.dat.zip"
+  }
+]
+```
+
+### Index
+
+Complete list of files for this build with: filename, checksum, file size, and list of files for MIX archives.
+
+* **NAME** - File name
+* **CHECKSUM** - SHA256 hash of file
+* **SIZE** - File size
+* **FILES** - _OPTIONAL_ List of files inside of MIX archives
+  * **NAME** - File name
+  * **CHECKSUM** - CRC32 hash of file data
+  * **OFFSET** - Offset of file in MIX archive
+  * **SIZE** - Size of file data
+
+```json
+[
+  {
+    "name": "game.exe",
+    "checksum": "SHA256-HASH",
+    "size": 8691743
+  },
+  {
+    "name": "data/Always.dat",
+    "checksum": "SHA256-HASH",
+    "size": 570961432,
+    "files": [
+      {
+        "name": "mp_wep_gdi.w3d",
+        "checksum": "CRC32_HASH",
+        "offset": 0,
+        "size": 3524
+      }
+    ]
+  }
+]
+```

docs/file_formats/MIX.md

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+# Westwood Renegade MIX Archive
+
+with W3D Hub / Tiberian Technologies alterations
+
+The .MIX archive file format is used by Renegade as _yes_.
+
+> [!IMPORTANT]
+> The MIX format has no notion about directories.
+>
+> Each file name **MUST** be unique.
+>
+> e.g. `data/map.dds` and `data/RA_Under/MAP.dds` have the same base file name
+> and therefore **MUST** raise an error when writing.
+
+> [!NOTE]
+> `io_pos` is the current position on the seek head of the open file
+
+## Reading
+
+* Read [Header](#header)
+    * validate MIME type (`MIX1` or `MIX2`)
+* Jump to io_pos `file_data_offset`
+* Read `file_count`
+* Read array of [`file_data`](#file-data-array)
+* Jump to io_pos `file_names_offset`
+* Read `file_count`
+* Read array of [`file_names`](#file-names-array)
+* Read file blobs
+    * For each file's [`file_data`](#file-data-array)
+        * Jump io_pos to `file_content_offset`
+        * Read `file_content_length`
+* Done.
+
+## Writing
+
+* Write MIME type (`MIX1` or `MIX2`)
+* Jump to io_pos `16`
+* Write file blobs
+    * **IMPORTANT:** Add `-io_pos & 7` padding to io_pos **AFTER** each file blob is written
+    * Save io_pos as `file_data_offset`
+* Write `file_count`
+    * Write array of [`file_data`](#file-data-array)
+    * Save io_pos as `file_names_offset`
+* Write `file_count`
+    * Write array of [`file_names`](#file-names-array)
+        * **IMPORTANT:** Ensure file names are null terminated and DO NOT exceed 254 (+ null byte) characters in length.
+* Jump to io_pos `4`
+    * Write [`file_data_offset`](#header)
+    * Write [`file_names_offset`](#header)
+    * Write [`reserved`](#header)
+* Done.
+
+## Pseudo Example:
+
+```yml
+header:
+  mime: MIX1 or MIX2
+  file_data_offset: 0x1024EAEA
+  file_names_offset: 0x8192EAEA
+  reserved: 0
+
+files:
+  array:
+    - file_blob
+
+file_data:
+  file_count: 0x000021
+  array:
+    file_name_crc32: 0xEFEFEFEF
+    file_content_offset: 0x3217DEAD
+    file_content_length: 0x0018BEEF
+
+file_names:
+  file_count: 0x000021
+  array:
+    file_name_length: 0xff
+    file_name: "mp_wep_gdi.w3d"
+```
+
+## MIME Types
+
+### MIX1 `0x3158494D`
+
+Westwood Farm Fresh Organic.
+
+### MIX2 `0x3258494D`
+
+Same as `MIX1`. `MIX2` hints to the engine's file reader to decrypt files before use.
+
+## Data Structures
+
+### Header
+
+| Name              | Offset | Type    | Description                                                         |
+|-------------------|--------|---------|---------------------------------------------------------------------|
+| MIME              | 0      | int32_t | 4 bytes representing `MIX1` (`0x3158494D)` or `MIX2` (`0x3258494D`) |
+| File Data Offset  | 4      | int32_t | Offset in MIX archive that [`file_data`](#file-data) data starts    |
+| File Names Offset | 8      | int32_t | Offset in MIX archive that [`file_name`](#file-names) data starts   |
+| RESERVED          | 12     | int32_t | Unused reserved int. Write as `0`                                   |
+
+### File
+
+| Name      | Offset  | Type                        | Description   |
+|-----------|---------|-----------------------------|---------------|
+| File Blob | complex | char[`file_content_length`] | File contents |
+
+### File Data
+
+| Name       | Offset             | Type    | Description                    |
+|------------|--------------------|---------|--------------------------------|
+| File Count | `file_data_offset` | int32_t | Number of files in MIX archive |
+
+### File Data Array
+
+| Name                | Offset                                     | Type     | Description                                            |
+|---------------------|--------------------------------------------|----------|--------------------------------------------------------|
+| File Name CRC32     | `file_data_offset` + 4 * (index * sizeof)  | uint32_t | CRC32 of **UPPERCASE** file name in network byte order |
+| File Content Offset | `file_data_offset` + 8 * (index * sizeof)  | uint32_t | File content offset                                    |
+| File Content Length | `file_data_offset` + 12 * (index * sizeof) | uint32_t | File content length                                    |
+
+### File Names
+
+| Name       | Offset              | Type    | Description                    |
+|------------|---------------------|---------|--------------------------------|
+| File Count | `file_names_offset` | int32_t | Number of files in MIX archive |
+
+### File Names Array
+
+| Name             | Offset  | Type                     | Description                                     |
+|------------------|---------|--------------------------|-------------------------------------------------|
+| File Name Length | complex | uint8_t                  | Length of string in bytes, including null byte. |
+| File Name        | complex | char[`file_name_length`] | null terminated string                          |

docs/file_formats/W3D_HUB_PATCH.md

@@ -0,0 +1,19 @@
+# W3D Hub Patch
+A W3D Hub Patch
+
+A `.w3dhub.patch` is included in MIX Patch files.
+It contains instructions for updating the target MIX.
+
+JSON file with a static CRC32 of `E6FE46B8`
+
+## Example:
+```json
+{
+  "removedFiles": [
+    "sov_v_mad.gif"
+  ],
+  "updatedFiles": [
+    "sov_v_mad.w3d"
+  ]
+}
+```

docs/protocols/LAN_DISCOVERY.md

@@ -0,0 +1,36 @@
+> [!NOTE]
+> DRAFT
+
+# LAN Discovery
+
+Doing things
+
+Broadcast port: 4898
+
+| Name              | Type     | Description                                                              |
+|-------------------|----------|--------------------------------------------------------------------------|
+| Version           | int32_t  | Version of protocol this application supports                            |
+| Owner             | string   | Nickname of application's active user                                    |
+| Hostname          | string   | Name of device                                                           |
+| UUID              | string   | Unique identifier for this application                                   |
+| Application       | string   | Name of application                                                      |
+| Features          | array    | Array of strings naming features the application supports                |
+| Service Port      | uint16_t | Dynamically assigned TCP port that interested parties should connect too |
+
+> [!NOTE]
+> Max packet size for UDP broadcast may need to be limited to 512 bytes
+
+```json
+{
+  "version": 0,
+  "owner": "cyberarm",
+  "hostname": "PC-1692",
+  "uuid": "019bcf1e-a22e-7fe0-a3db-3a9d37bfc6fa",
+  "application": "W3D Hub Linux Launcher",
+  "features": [
+    "launcher_remote:3",
+    "package_share:1"
+  ],
+  "service_port": 56802
+}
+```

docs/protocols/LAN_PACKAGE_SHARE.md

@@ -0,0 +1,9 @@
+> [!NOTE]
+> DRAFT
+
+# LAN Package Share
+
+Authentication is not required, only user opt-in to enable package sharing from their application.
+
+* List available packages
+* upload or download verified packages between other applications on LAN network

docs/protocols/LAUNCHER_REMOTE.md

@@ -0,0 +1,9 @@
+> [!NOTE]
+> DRAFT
+
+# Launcher Remote
+
+* Get list of available, installed, and in progress applications
+* Trigger download or update of application
+* Delete application
+* Join server

lib/api.rb

@@ -60,15 +60,15 @@ class W3DHub
       end
 
       # Handle arbitrary urls that may come through
-      url = nil
       if path.start_with?("http")
         uri = URI(path)
+
         endpoint = uri.origin
         path = uri.request_uri
-      else
-        url = "#{endpoint}#{path}"
       end
 
+      url = "#{endpoint}#{path}"
+
       logger.debug(LOG_TAG) { "Fetching #{method.to_s.upcase} \"#{url}\"..." }
 
       # Inject Authorization header if account data is populated

lib/api/server_list_server.rb

@@ -20,8 +20,12 @@ class W3DHub
 
         @status  = Status.new(@data[:status])
 
-        @ping_interval = 30_000
+        # if we're on unix and using the PingManager then check every second since
+        # we're not _actually_ pinging the server.
+        @ping_interval = W3DHub.unix? ? 1_000 : 60_000
         @last_pinged = Gosu.milliseconds + @ping_interval + 1_000
+
+        Store.ping_manager.add_address(@address)
       end
 
       def update(hash)
@@ -49,6 +53,16 @@ class W3DHub
         if force_ping || Gosu.milliseconds - @last_pinged >= @ping_interval
           @last_pinged = Gosu.milliseconds
 
+          if W3DHub.unix?
+            average_ping = Store.ping_manager.ping_for(@address)
+
+            @ping = average_ping.negative? ? NO_OR_BAD_PING : average_ping
+
+            States::Interface.instance&.update_server_ping(self)
+          end
+
+          return unless W3DHub.windows?
+
           W3DHub::BackgroundWorker.foreground_parallel_job(
             lambda do
               W3DHub.command("ping #{@address} #{W3DHub.windows? ? '-n 3' : '-c 3'}") do |line|

lib/application_manager.rb

@@ -255,13 +255,18 @@ class W3DHub
           !server.status.password &&
           server.status.player_count < server.status.max_players
       end
+      # sort by player count HIGH to LOW
+      # and by ping LOW to HIGH
+      server_options.sort! do |a, b|
+        [b.status.player_count, a.ping] <=> [a.status.player_count, b.ping]
+      end
 
       # try to find server with lowest ping and matching version
       found_server = server_options.find { |server| server.version == app_data[:installed_version] }
       # try to find server with lowest ping and undefined version
       found_server ||= server_options.find { |server| server.version == Api::ServerListServer::NO_OR_DEFAULT_VERSION }
 
-      found_server ? found_server : nil
+      found_server
     end
 
     def play_now(app_id, channel)

lib/pages/server_browser.rb

@@ -196,13 +196,13 @@ class W3DHub
 
       def ping_icon(server)
         case server.ping
-        when 0..150
+        when 0..50
           @ping_icons[:good]
-        when 151..200
+        when 51..150
           @ping_icons[:fair]
-        when 201..1_000
+        when 151..200
           @ping_icons[:poor]
-        when 1_001..5_000
+        when 201..1_000
           @ping_icons[:bad]
         else
           @ping_icons[:unknown]

lib/ping.rb

@@ -0,0 +1,166 @@
+require "async"
+require "socket"
+require "securerandom"
+
+class W3DHub
+  class Ping
+    ICMPHeader = Data.define(:type, :code, :checksum, :_ping_id, :_sequence_id, :data)
+    EchoRequest = Struct.new(:ping_id, :sequence_id, :data, :time, :timed_out)
+
+    ICMP_ECHOREPLY = 0
+    ICMP_ECHO      = 8
+    ICMP_SUBCODE   = 0
+
+    BIT_PACKER = "C2 n3 A*".freeze
+    MINIMUM_INTERVAL = 250 # ms # intervals below 200ms are considered rude and may be dropped due to flooding.
+    ECHO_REQUEST_HISTORY = 30 # 100 # keep the last n requests
+
+    attr_reader :address
+
+    def initialize(address:, count: 10, ttl: 120, interval: 1_000, data: nil)
+      @address = address
+      @count = count
+      @ttl = ttl
+      @interval = interval.to_i < MINIMUM_INTERVAL ? MINIMUM_INTERVAL : interval # ms
+      @data = data
+
+      # circular buffer
+      @echo_requests = Array.new(ECHO_REQUEST_HISTORY) { EchoRequest.new(-1, -1, "", nil, false) }
+      @echo_requests_index = 0
+
+      # NOTE: The PING_ID _might_ be overruled by the kernel and should not be used
+      #       to check that any received echo replies are ours.
+      #
+      #       Sequence ID and Data appear to be unmodified.
+      @ping_id = SecureRandom.hex.to_i(16) & 0xffff
+      @sequence_id = SecureRandom.hex.to_i(16) & 0xffff
+
+      addresses = Addrinfo.getaddrinfo(@address, nil, Socket::AF_INET, :DGRAM)
+      raise "NO ADDRESSES!" if addresses.empty?
+
+      @socket_address = addresses.sample.to_sockaddr
+
+      @socket = Socket.new(Socket::AF_INET, Socket::SOCK_DGRAM, Socket::IPPROTO_ICMP)
+      @socket.setsockopt(Socket::SOL_SOCKET, Socket::IP_TTL, @ttl)
+    end
+
+    # Perform a checksum on the message.  This is the sum of all the short
+    # words and it folds the high order bits into the low order bits.
+    def message_checksum(message)
+      length    = message.length
+      num_short = length / 2
+      check     = 0
+
+      message.unpack("n#{num_short}").each do |short|
+        check += short
+      end
+
+      check += message[length - 1, 1].unpack1("C") << 8 if (length % 2).positive?
+
+      check = (check >> 16) + (check & 0xffff)
+      ~((check >> 16) + check) & 0xffff
+    end
+
+    def random_data
+      SecureRandom.hex
+    end
+
+    def monotonic_time
+      Process.clock_gettime(:CLOCK_MONOTONIC, :millisecond)
+    end
+
+    def verified?(message)
+      data = message.unpack(BIT_PACKER)
+      checksum = data[2]
+
+      # set checksum in message to 0
+      data[2] = 0
+
+      checksum == message_checksum(data.pack(BIT_PACKER))
+    end
+
+    def request_complete?(request)
+      request.timed_out || !request.time.nil?
+    end
+
+    def packet_loss
+      completed_requests = @echo_requests.select { |r| request_complete?(r) }
+      failed_requests = completed_requests.select(&:timed_out)
+
+      # 0% packet loss 😎
+      return 0.0 if failed_requests.empty?
+
+      # 100% packet loss
+      return 1.0 if failed_requests.size == completed_requests.size
+
+      failed_requests.size / completed_requests.size.to_f
+    end
+
+    def average_ping
+      times = @echo_requests.select { |r| request_complete?(r) && !r.timed_out }.map(&:time)
+
+      return -1 unless times.size.positive?
+
+      times.sum.to_f / times.size
+    end
+
+    # returns true if any echo requests have completed (reply received or timed out) and packet loss is less than 30%
+    def okay?
+      completed_requests = @echo_requests.select { |r| request_complete?(r) }.size
+
+      completed_requests.positive? && packet_loss < 0.3
+    end
+
+    def ping(count = @count)
+      return if count <= 0
+
+      Async do |task|
+        @count.times do
+          task.Async do |subtask|
+            @sequence_id = (@sequence_id + 1) % 0xffff
+            data = @data || random_data
+
+            checksum = 0
+            message = [ICMP_ECHO, ICMP_SUBCODE, checksum, @ping_id, @sequence_id, data].pack(BIT_PACKER)
+            checksum = message_checksum(message)
+            message = [ICMP_ECHO, ICMP_SUBCODE, checksum, @ping_id, @sequence_id, data].pack(BIT_PACKER)
+
+            @socket.send(message, 0, @socket_address)
+
+            s = monotonic_time
+            request = @echo_requests[@echo_requests_index]
+            request.ping_id = @ping_id
+            request.sequence_id = @sequence_id
+            request.data = data
+            request.time = nil
+            request.timed_out = false
+            @echo_requests_index = (@echo_requests_index + 1) % ECHO_REQUEST_HISTORY
+
+            subtask.with_timeout(2) do
+              loop do
+                data, _addrinfo = @socket.recvfrom(1500)
+
+                # ignore corruption
+                next unless verified?(data)
+
+                header = ICMPHeader.new(*data.unpack(BIT_PACKER))
+
+                if header.type == ICMP_ECHOREPLY && header._sequence_id == request.sequence_id && header.data == request.data
+                  duration = monotonic_time - s
+                  request.time = duration
+
+                  break
+                end
+              end
+            rescue Async::TimeoutError
+              request.timed_out = true
+            end
+          end
+
+          # Don't send out pings in a flood, it's considered rude.
+          sleep @interval / 1000.0
+        end
+      end
+    end
+  end
+end

lib/ping_manager.rb

@@ -0,0 +1,54 @@
+class W3DHub
+  class PingManager
+    Container = Struct.new(:pinger, :last_ping_time_ms)
+    PING_INTERVAL = 60_000
+
+    def initialize
+      @containers = {}
+      @addresses = []
+    end
+
+    def monitor(task)
+      task.async do |subtask|
+        while BackgroundWorker.alive?
+          # activate new addresses
+          @addresses.each do |address|
+            @containers[address] ||= Container.new(Ping.new(address: address), -PING_INTERVAL * 2)
+          end
+
+          # cleanup old addresses
+          @containers.each_key do |key|
+            @containers.delete(key) unless @addresses.find { |a| a == key }
+          end
+
+          # ping the pingers
+          @containers.each_value do |container|
+            next unless Gosu.milliseconds - container.last_ping_time_ms >= PING_INTERVAL
+
+            container.last_ping_time_ms = Gosu.milliseconds
+
+            subtask.async do
+              container.pinger.ping
+              pp [container.pinger.address, container.pinger.average_ping]
+            end
+          end
+
+          sleep 0.001
+        end
+      end
+    end
+
+    def add_address(address)
+      @addresses << address
+      @addresses.uniq!
+    end
+
+    def ping_for(address)
+      @containers[address]&.pinger&.average_ping&.round || -1
+    end
+
+    def remove_address(address)
+      @addresses.delete(address)
+    end
+  end
+end

lib/window.rb

@@ -7,6 +7,9 @@ class W3DHub
       Store[:server_list] = []
       Store[:settings] = Settings.new
       Store[:application_manager] = ApplicationManager.new
+      Store[:ping_manager] = PingManager.new
+
+      BackgroundWorker.parallel_job(-> { Async { |task| Store.ping_manager.monitor(task) } }, nil)
 
       Store[:main_thread_queue] = []
 

w3d_hub_linux_launcher.rb

@@ -106,6 +106,8 @@ require_relative "lib/cache"
 require_relative "lib/settings"
 require_relative "lib/ww_mix"
 require_relative "lib/ico"
+require_relative "lib/ping"
+require_relative "lib/ping_manager"
 require_relative "lib/broadcast_server"
 require_relative "lib/hardware_survey"
 require_relative "lib/game_settings"