Interposer 1.0.3 Release Notes

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What's Changed

DNS Redirection

DNS redirection intercepts hostname lookups before they reach the operating system's resolver and substitutes one hostname (or IP literal) for another. The game opens a socket to a different server than the one it was hard-coded to use, with no patching, no hosts file editing, and no administrator privileges required.

It was common for games to hard code hostnames into the executable for query/master servers. By crafting a simple regex rule, you can redirect all hostname lookups to a different service. For example, this can be used to adapt a game to use the fantastic OpenSpy service using the following redirect rule:

DnsRedirects:
  - Pattern: '(.+)\.gamespy\.com'
    Replacement: '$1.openspy.net'

Note that this happens at the API level with no binary patching required, which also opens up the opportunity to redirect to hostnames of any length.

Rules are ECMAScript regex (case-insensitive) and support up to nine capture groups ($1 – $9). Replacements may be hostnames (resolved normally afterwards) or IPv4 / IPv6 literals (returned directly without DNS). The first matching rule wins.

DNS redirection applies to the following Winsock resolver functions across both ws2_32.dll and wsock32.dll:

• getaddrinfo, GetAddrInfoW
• GetAddrInfoExW, GetAddrInfoExA
• gethostbyname (both Winsock 2 and Winsock 1 entry points)

When Logging.Network is enabled, every triggered redirect is recorded in the session log as [DNS REDIRECT] showing both the original and substituted hostnames. See the DNS Redirection page for full pattern syntax and examples.

Expanded File Hook Coverage

File redirection and logging now cover the full set of file-management APIs in kernel32.dll, not just opens and attribute queries. Newly hooked functions:

Function	Variants	Behaviour
FindFirstFileEx	W, A	Logged as [FILE FIND]; redirected before the search begins
DeleteFile	W, A	Logged as [FILE DELETE]; redirected before the delete
MoveFile	W, A	Logged as [FILE MOVE]; both source and destination paths are redirected independently
MoveFileEx	W, A	As above, with dwFlags preserved
CopyFile	W, A	Logged as [FILE COPY]; both source and destination paths are redirected independently
CopyFileEx	W, A	As above, with progress callback and cancel pointer preserved

Games that probe their install directory with FindFirstFileEx (instead of the older FindFirstFile) are now visible to the file logger, and games that delete, move, or copy save data through any of these APIs will have those operations transparently routed by FileRedirects rules. ANSI variants convert to wide strings and delegate to the wide implementation, so a single rule covers both code paths. A thread-local reentrancy guard prevents MoveFile and CopyFile from being double-logged when their internal implementations call through to their Ex counterparts. This should result in better compatiblity across the board.

File Redirects: Auto-create Parent Directories on Write

When a FileRedirects rule rewrites a path that the game is opening for write (GENERIC_WRITE, FILE_WRITE_DATA, or FILE_APPEND_DATA), the redirect target's parent directory tree is now created automatically before the underlying CreateFile call. Games that hard-code save paths into a fixed install directory and assume the directory already exists will no longer fail when those writes are redirected to a fresh %APPDATA% or %USERPROFILE% location that has not yet been created.

Directory creation is silent — already-present directories are detected via the original GetFileAttributesW trampoline and skipped, and each segment is created with CreateDirectoryW so existing directories simply return ERROR_ALREADY_EXISTS and are ignored.

File Redirects: Backslash Normalization

Replacement strings produced by FileRedirects rules are now normalized to collapse runs of consecutive backslashes down to a single backslash. Capture groups that include a leading slash, or replacement templates that accidentally double-up separators (a common copy/paste mistake), no longer produce paths like C:\Users\Player\\Saved Games\\My Game\save.dat that some games and APIs reject.

UNC prefixes (\\server\share) and extended-length prefixes (\\?\) are preserved.

Plugins: Recursive Subdirectory Loading

.interposer\Plugins\ is now scanned recursively. Every .dll and .asi file under the Plugins directory and any of its subdirectories is loaded on startup, with no maximum depth. This makes it practical to ship multi-file plugins (a plugin DLL plus its own dependencies, configuration, or assets) in their own subfolder without needing all the plugin files flattened into a single directory:

.interposer\
  Plugins\
    CDKey\
      LANCommander.Interposer.Plugin.CDKey.dll
    OtherPlugin\
      OtherPlugin.dll
      OtherPlugin.dependency.dll

Each loaded plugin is recorded in the session log as [PLUGIN LOAD] with its full path, so the source subdirectory of every loaded module is visible at a glance.

Config: Redirects → FileRedirects

The configuration key for file redirect rules has been renamed from Redirects to FileRedirects. The new name better distinguishes file redirects from the new DnsRedirects and from any future redirect categories.

FileRedirects:
  - Pattern: 'C:\\Games\\MyGame\\Saves\\(.+)'
    Replacement: '%APPDATA%\MyGame\Saves\$1'

Backwards compatibility

The legacy key name Redirects is still accepted and behaves identically. It is read only when FileRedirects is not present, so existing configs continue to work unchanged. New configs should use FileRedirects.