Module wire 

rsync’s daemon protocol, pinned at protocol 29: the @RSYNCD: text handshake, the argument list, multiplexed framing, the file list, and the MD4 checksums. Shared by the daemon (src/server/rsync/) and the client (src/client/rsync/).

Why 29: it is the smallest version rsync 3.2.7 still speaks in full. There are no compat flags, no checksum or compression negotiation, no incremental recursion, plain int32 file indexes, fixed-width file-list fields, and a client→daemon direction that is never multiplexed. Everything is MD4: the whole-file sum is MD4(le32(seed) ‖ data). Advertise exactly 29.0: a non-zero sub-version makes a 3.2.7 peer drop to 28.

Structs

Entry

One file-list entry. path is relative to the transfer root, /-separated.

FlistLimits

What one file list may hold: entries (every entry read counts, including the devices and specials that are skipped), and name plus symlink-target bytes over all entries.

FlistWriter

Encodes entries in order, keeping the “previous entry” state both ends share.

MuxReader

A demultiplexing reader: MSG_DATA becomes a byte stream, other messages are collected.

Request

The options a sender cares about, parsed from the argument list.

Enums

Kind

Constants

CHUNK

Literal data is sent in pieces of at most this many bytes (rsync’s CHUNK_SIZE).

GREETING

ITEM_BASIS_TYPE_FOLLOWS

ITEM_IS_NEW

ITEM_TRANSFER

ITEM_XNAME_FOLLOWS

MAX_ARGS

MAX_ENTRIES

Entries in one file list a daemon sends (what the client reads on a download).

MAX_FILTER_BYTES

Total bytes of filter rules a client may send.

MAX_LINE

A text line of the handshake, an argument, or a module line.

MAX_NAME

A file-list name.

MAX_SUM_COUNT

Block checksums one request may carry (count × (4 + s2length) bytes are read and dropped).

MAX_UPLOAD_LIST_ENTRIES

Entries in one uploading client’s file list, devices and specials included: twice the files one upload may deliver, so the directories and symlinks around them fit.

MAX_UPLOAD_LIST_NAME_BYTES

Name and symlink-target bytes in one uploading client’s file list, all entries together. Every name reaches the model in rsync_upload_request, so this also bounds that event.

MSG_DATA

MSG_ERROR

MSG_ERROR_EXIT

MSG_ERROR_XFER

MSG_INFO

MSG_IO_ERROR

MSG_NOOP

MSG_WARNING

NDX_DONE

PROTOCOL

S_IFDIR

S_IFLNK

S_IFMT

S_IFREG

Functions

auth_response

The answer to @RSYNCD: AUTHREQD <challenge> at protocol 29 (no digest list was offered, so the daemon uses MD4 with a zero seed): base64 without padding of MD4(00 00 00 00 ‖ password ‖ challenge).

content_json

Text when it is printable UTF-8, hex otherwise, with the encoding named.

data_frames

MSG_DATA frames for a byte stream, split at 0xFFFF bytes.

entry_from_json

One entry the model described: {path, type, content, encoding, mode, mtime, target, uid, gid}.

entry_json

An entry as the model sees it.

file_sum

The whole-file checksum at protocol 29: MD4(le32(seed) ‖ data), the seed always first.

frame

One multiplexed frame: a little-endian (tag << 24 | len) header, then the payload.

le32

list_sum

The -c file-list checksum: MD4 of the contents, unseeded.

longint

md4

MD4 over the pieces, in order.

parse_args

Parse the daemon argument list (--server --sender -logDtpr . mod/path).

sort

sort_key

rsync’s file-list order (f_name_cmp at protocol ≥ 29) as a sort key: “.” first; within a directory, non-directories by bytes, then directories by name + “/”, each followed by its subtree.