Wireless file transfer for retro handhelds.

retsend (retro + sending) is a Rust LocalSend client for retro handhelds: send and receive files with your phone or PC over Wi-Fi, no cable or SSH. Compatible with the official LocalSend apps.

It targets PortMaster-compatible Linux handhelds (Knulli, muOS, ROCKNIX — Anbernic/TrimUI class devices, gamepad-only, no compositor) and runs on regular desktop Linux too.

Why?

Getting files onto a handheld usually means pulling the SD card or setting up SSH/SMB. Phones and desktops already have LocalSend — this is the missing end: a client built for a gamepad and screen, moving files both ways.

Features

• Discovery — a live radar of nearby devices (LocalSend protocol v2.1).
• Receive — accept/decline dialog with countdown, speed/ETA, and cancel from either side; quick-save mode auto-accepts.
• Send — gamepad file browser with multi-select and per-file progress; pin the folders and files you send often and they lead every listing.
• Save routes — received ROMs land in the console folder they belong to, detected from the card; per-extension overrides on top.
• Encryption — the protocol's HTTPS mode, on by default; works with the official app's default settings both ways.
• Settings on device — alias, save folder, and port, applied live.
• Headless — retsend --receive runs with no screen, for SSH and scripting.
• Small and simple — no async runtime, a minimal HTTP server, system SDL2.

Install (PortMaster devices)

Grab retsend-portmaster.zip from Releases and unpack it into your ports folder (e.g. /roms/ports/).

Building & running (desktop)

System SDL2 is the only native dependency. On Debian/Ubuntu:

sudo apt-get install -y build-essential pkg-config libsdl2-dev
cargo run

Files passed as arguments (cargo run -- file1 file2) come pre-selected in the send browser.

Two instances on one machine discover each other (multicast loopback) — handy for trying both sides of a transfer without a second device:

RETSEND_DATA_DIR=/tmp/ls-a cargo run &
RETSEND_DATA_DIR=/tmp/ls-b cargo run

Tests are headless (no SDL, no network setup needed):

cargo test

Controls

Pad	Keyboard	Action
D-pad / stick	Arrows	Navigate
A	Enter	Send to device · select file · accept · type
B	Esc	Back · decline · cancel · leave the keyboard
X	X / Bksp	Erase a character · take every file in the folder
Y	Y	Pin / unpin the row under the cursor
Start	F1	Confirm send · OK (keyboard)
Select	Tab / F5	Refresh radar · switch roots · layer (keyboard)
L1 / R1	PgUp / PgDn	Switch tabs · page the file browser

Configuration

config.toml lives in the data dir (created with defaults on first run) and everything in it is also editable from the Settings screen, except:

• [network] https = false — fall back to the protocol's plain-http mode
• [network] announce_interval_secs — multicast announce cadence
• [transfer] browser_roots — extra mount points for the file browser
• [transfer] history_limit — max transfers kept in the History tab (default 200)

Received files land in save_dir by default, but ROMs are sorted on their own: retsend looks for the console folders already present in save_dir and routes by extension — .gba into gba, .sfc into snes, .ws into wswan. The folder names come from KNULLI, ROCKNIX, and muOS themselves, which disagree (Mega Drive is megadrive, genesis, and md respectively — all three are recognized), and SD-card templates that rename folders to Nintendo Game Boy Advance (GBA) are matched through the code in parentheses. Nothing is created for you: a console folder that isn't there gets no route, so on desktop this does nothing. Only extensions that name exactly one console take part — .zip, .iso, .bin, and .md never do. Turn it off with Settings → Auto save routes or [transfer] auto_routes = false.

[transfer.routes] overrides all of that per file extension, and wins over the detected routes. Edit it on the device from Settings → Save routes (type the extension, pick the folder), or in the config:

[transfer.routes]
gbc = "gb"                    # relative → <save_dir>/gb
gba = "/roms/gba"             # absolute → used as-is
png = "/roms/screenshots"

Extensions match case-insensitively, folders are created on demand, and anything without a matching route still lands in save_dir.

X in the send browser takes every file of the folder you are looking at into the selection, and gives them back on a second press. Subfolders are left alone: the protocol has no notion of a directory, so a send is always a flat list of files — see sanitize_filename for what that means on the receiving end.

Y pins whatever the cursor is on — a folder you send from often, or a single file. Pinned rows lead every listing, so a pinned folder is one press away from anywhere in the tree, and a pinned file can be selected and sent without navigating at all. Pins live in [transfer] pinned_paths; the folder pickers list only the pinned folders, and a pin on a card that isn't in the slot is skipped rather than shown dead. The send browser also reopens in the folder your last send came from ([transfer] last_send_dir).

Environment variables override paths and control logging at launch: RETSEND_DATA_DIR, RETSEND_CONFIG, RETSEND_SAVE_DIR, RETSEND_SCALE, RETSEND_GLES=0|1, RETSEND_LOG_LEVEL, RETSEND_LOG_FILE, RETSEND_PANIC_FILE.