rpc: JSON-RPC-over-HTTP control interface — native httpd + json + dispatch, core provider

src/modules/rpc/core.rs

@@ -0,0 +1,51 @@
+//! rpc core provider — introspection: `rpc.methods` (list the interface),
+//! `rpc.info` (identity + methods), and `server.info` / `stats.get` (identity +
+//! network counts). InspIRCd's `m_rpc_core` + the legacy `stats.get`.
+
+use super::json::{obj, qstr};
+use super::{RpcError, ALL_METHODS};
+use crate::server::{now, Server, VERSION};
+
+/// `{"methods":[...]}` — every method name the interface exposes.
+fn methods_json() -> String {
+    let list: Vec<String> = ALL_METHODS.iter().map(|m| qstr(m)).collect();
+    format!("[{}]", list.join(","))
+}
+
+/// `rpc.methods` and `rpc.info`.
+pub fn rpc_info(s: &Server, method: &str) -> Result<String, RpcError> {
+    if method == "rpc.methods" {
+        return Ok(obj(&[("methods", methods_json())]));
+    }
+    // rpc.info: identity + the method list
+    let mut fields = identity_fields(s);
+    fields.push(("methods", methods_json()));
+    Ok(obj(&fields))
+}
+
+/// `server.info` / `stats.get` — identity plus live network counts.
+pub fn server_info(s: &Server) -> Result<String, RpcError> {
+    Ok(obj(&identity_fields(s)))
+}
+
+/// The shared identity + counts fields.
+fn identity_fields(s: &Server) -> Vec<(&'static str, String)> {
+    let opers = s.users.values().filter(|u| u.flags.oper).count();
+    let users_local = s.users.len();
+    let users_total = users_local + s.remote_users.len();
+    let counts = obj(&[
+        ("users", users_total.to_string()),
+        ("users_local", users_local.to_string()),
+        ("opers", opers.to_string()),
+        ("channels", s.channels.len().to_string()),
+    ]);
+    vec![
+        ("name", qstr(&s.name)),
+        ("id", qstr(&s.sid)),
+        ("description", qstr(&s.server_desc)),
+        ("version", qstr(&format!("echoircd-{VERSION}"))),
+        ("boot_time", s.created.to_string()),
+        ("current_time", now().to_string()),
+        ("counts", counts),
+    ]
+}

src/modules/rpc/httpd.rs

@@ -0,0 +1,209 @@
+//! The RPC HTTP server: a blocking listener thread that accepts a connection,
+//! reads one HTTP request, authenticates it, and forwards the JSON-RPC body to the
+//! core as `Event::RpcRequest` — then writes back whatever the core replies. Low
+//! volume (admin tooling), so thread-per-connection is fine. Native `TcpStream`
+//! only; no `unsafe`, no new crate.
+
+use std::io::{Read, Write};
+use std::net::{TcpListener, TcpStream};
+use std::sync::mpsc::{channel, Sender};
+use std::time::Duration;
+
+use crate::ircd::Event;
+
+const MAX_REQUEST: usize = 256 * 1024;
+const IO_TIMEOUT: Duration = Duration::from_secs(20);
+const CORE_TIMEOUT: Duration = Duration::from_secs(15);
+
+/// Accept loop. Never returns while the listener is alive.
+pub fn serve(listener: TcpListener, tx: Sender<Event>, user: String, token: String) {
+    for conn in listener.incoming() {
+        let Ok(stream) = conn else { continue };
+        let (tx, user, token) = (tx.clone(), user.clone(), token.clone());
+        std::thread::spawn(move || {
+            let _ = handle(stream, &tx, &user, &token);
+        });
+    }
+}
+
+/// Constant-time-ish equality (length-guarded so OpenSSL's memcmp is safe).
+fn ct_eq(a: &[u8], b: &[u8]) -> bool {
+    a.len() == b.len() && openssl::memcmp::eq(a, b)
+}
+
+/// Verify the `Authorization` header carries the right token, via HTTP Basic
+/// (`base64(user:token)`) or Bearer (`token`).
+fn auth_ok(header: Option<&str>, user: &str, token: &str) -> bool {
+    let Some(h) = header else { return false };
+    if let Some(b64) = h
+        .strip_prefix("Basic ")
+        .or_else(|| h.strip_prefix("basic "))
+    {
+        let Ok(raw) = openssl::base64::decode_block(b64.trim()) else {
+            return false;
+        };
+        let Ok(text) = String::from_utf8(raw) else {
+            return false;
+        };
+        let Some((u, t)) = text.split_once(':') else {
+            return false;
+        };
+        return ct_eq(u.as_bytes(), user.as_bytes()) && ct_eq(t.as_bytes(), token.as_bytes());
+    }
+    if let Some(bearer) = h
+        .strip_prefix("Bearer ")
+        .or_else(|| h.strip_prefix("bearer "))
+    {
+        return ct_eq(bearer.trim().as_bytes(), token.as_bytes());
+    }
+    false
+}
+
+fn handle(
+    mut stream: TcpStream,
+    tx: &Sender<Event>,
+    user: &str,
+    token: &str,
+) -> std::io::Result<()> {
+    stream.set_read_timeout(Some(IO_TIMEOUT))?;
+    stream.set_write_timeout(Some(IO_TIMEOUT))?;
+
+    // read until we have the full header block, then the declared body
+    let mut buf = Vec::new();
+    let mut chunk = [0u8; 8192];
+    let (mut head_end, mut content_len) = (None, 0usize);
+    loop {
+        if head_end.is_none() {
+            if let Some(pos) = find_headers_end(&buf) {
+                head_end = Some(pos);
+                content_len = content_length(&buf[..pos]);
+            }
+        }
+        if let Some(he) = head_end {
+            if buf.len() >= he + content_len {
+                break;
+            }
+        }
+        if buf.len() > MAX_REQUEST {
+            return respond(&mut stream, 413, "Payload Too Large", "{}");
+        }
+        let n = stream.read(&mut chunk)?;
+        if n == 0 {
+            break;
+        }
+        buf.extend_from_slice(&chunk[..n]);
+    }
+
+    let Some(he) = head_end else {
+        return respond(&mut stream, 400, "Bad Request", "{}");
+    };
+    let header_text = String::from_utf8_lossy(&buf[..he]).into_owned();
+    let body =
+        String::from_utf8_lossy(&buf[he + 4..(he + 4 + content_len).min(buf.len())]).into_owned();
+
+    // request line: only POST is accepted
+    let first = header_text.lines().next().unwrap_or("");
+    if !first
+        .split_whitespace()
+        .next()
+        .is_some_and(|m| m.eq_ignore_ascii_case("POST"))
+    {
+        return respond(&mut stream, 405, "Method Not Allowed", "{}");
+    }
+
+    // authenticate
+    let authz = header_line(&header_text, "authorization");
+    if !auth_ok(authz.as_deref(), user, token) {
+        return respond_with(
+            &mut stream,
+            401,
+            "Unauthorized",
+            "{\"error\":\"authentication required\"}",
+            Some("WWW-Authenticate: Basic realm=\"echoircd-rpc\""),
+        );
+    }
+
+    // parse the JSON-RPC request
+    let method = super::json::get_str(&body, "method");
+    let id = super::json::get_raw(&body, "id").unwrap_or_else(|| "null".to_string());
+    let params = super::json::get_raw(&body, "params").unwrap_or_else(|| "{}".to_string());
+    let Some(method) = method else {
+        let env = super::envelope(
+            "",
+            &id,
+            Err(super::RpcError {
+                code: -32600,
+                message: "Invalid Request: no method".into(),
+            }),
+        );
+        return respond(&mut stream, 200, "OK", &env);
+    };
+
+    // hand off to the core and wait for its reply
+    let (rtx, rrx) = channel::<String>();
+    if tx
+        .send(Event::RpcRequest {
+            method: method.clone(),
+            params,
+            id: id.clone(),
+            reply: rtx,
+        })
+        .is_err()
+    {
+        return respond(&mut stream, 503, "Service Unavailable", "{}");
+    }
+    match rrx.recv_timeout(CORE_TIMEOUT) {
+        Ok(resp) => respond(&mut stream, 200, "OK", &resp),
+        Err(_) => {
+            let env = super::envelope(
+                &method,
+                &id,
+                Err(super::RpcError::internal("core did not respond in time")),
+            );
+            respond(&mut stream, 504, "Gateway Timeout", &env)
+        }
+    }
+}
+
+/// Index of the `\r\n\r\n` that ends the header block.
+fn find_headers_end(buf: &[u8]) -> Option<usize> {
+    buf.windows(4).position(|w| w == b"\r\n\r\n")
+}
+
+/// The `Content-Length` from a header block (0 if absent/invalid).
+fn content_length(head: &[u8]) -> usize {
+    let text = String::from_utf8_lossy(head);
+    header_line(&text, "content-length")
+        .and_then(|v| v.trim().parse().ok())
+        .unwrap_or(0)
+}
+
+/// The value of a header, matched case-insensitively.
+fn header_line(head: &str, name: &str) -> Option<String> {
+    head.lines().find_map(|l| {
+        let (k, v) = l.split_once(':')?;
+        k.trim()
+            .eq_ignore_ascii_case(name)
+            .then(|| v.trim().to_string())
+    })
+}
+
+fn respond(stream: &mut TcpStream, code: u16, text: &str, body: &str) -> std::io::Result<()> {
+    respond_with(stream, code, text, body, None)
+}
+
+fn respond_with(
+    stream: &mut TcpStream,
+    code: u16,
+    text: &str,
+    body: &str,
+    extra: Option<&str>,
+) -> std::io::Result<()> {
+    let extra = extra.map(|e| format!("{e}\r\n")).unwrap_or_default();
+    let resp = format!(
+        "HTTP/1.1 {code} {text}\r\nContent-Type: application/json\r\nContent-Length: {}\r\n{extra}Connection: close\r\n\r\n{body}",
+        body.len()
+    );
+    stream.write_all(resp.as_bytes())?;
+    stream.flush()
+}

src/modules/rpc/json.rs

@@ -0,0 +1,215 @@
+//! Minimal JSON for the RPC subsystem — no serde (openssl+mio-only crate policy).
+//! Two jobs: pull a named field out of a flat-ish request object (`get_*`), and
+//! escape strings when *building* result JSON with `format!`. The scanners respect
+//! nesting and string escapes, so `get_raw` only ever matches a **top-level** key
+//! (a `"nick"` buried inside a nested value or another string won't false-match).
+
+/// Given `b[i] == b'"'`, return the index just past the closing quote.
+fn scan_string(b: &[u8], mut i: usize) -> Option<usize> {
+    debug_assert!(b[i] == b'"');
+    i += 1;
+    while i < b.len() {
+        match b[i] {
+            b'\\' => i += 2, // skip the escaped char
+            b'"' => return Some(i + 1),
+            _ => i += 1,
+        }
+    }
+    None
+}
+
+/// Given `i` at the first byte of a JSON value, return the index just past it.
+fn scan_value(b: &[u8], i: usize) -> Option<usize> {
+    match b.get(i)? {
+        b'"' => scan_string(b, i),
+        b'{' | b'[' => {
+            let (open, close) = if b[i] == b'{' {
+                (b'{', b'}')
+            } else {
+                (b'[', b']')
+            };
+            let mut depth = 0usize;
+            let mut j = i;
+            while j < b.len() {
+                match b[j] {
+                    b'"' => j = scan_string(b, j)?,
+                    c if c == open => {
+                        depth += 1;
+                        j += 1;
+                    }
+                    c if c == close => {
+                        depth -= 1;
+                        j += 1;
+                        if depth == 0 {
+                            return Some(j);
+                        }
+                    }
+                    _ => j += 1,
+                }
+            }
+            None
+        }
+        // scalar: number / true / false / null — up to the next delimiter
+        _ => {
+            let mut j = i;
+            while j < b.len() && !matches!(b[j], b',' | b'}' | b']' | b' ' | b'\t' | b'\n' | b'\r')
+            {
+                j += 1;
+            }
+            (j > i).then_some(j)
+        }
+    }
+}
+
+/// The raw text of top-level object key `key` in `obj` (value verbatim, incl. any
+/// quotes/braces), or `None` if the key isn't a top-level member.
+pub fn get_raw(obj: &str, key: &str) -> Option<String> {
+    let b = obj.as_bytes();
+    let mut i = obj.find('{')? + 1;
+    loop {
+        // skip whitespace / commas to the next key string
+        while i < b.len() && matches!(b[i], b' ' | b'\t' | b'\n' | b'\r' | b',') {
+            i += 1;
+        }
+        if i >= b.len() || b[i] == b'}' {
+            return None;
+        }
+        if b[i] != b'"' {
+            return None; // malformed
+        }
+        let key_end = scan_string(b, i)?;
+        let this_key = &obj[i + 1..key_end - 1];
+        // skip ws + ':'
+        let mut c = key_end;
+        while c < b.len() && matches!(b[c], b' ' | b'\t' | b'\n' | b'\r') {
+            c += 1;
+        }
+        if b.get(c) != Some(&b':') {
+            return None;
+        }
+        c += 1;
+        while c < b.len() && matches!(b[c], b' ' | b'\t' | b'\n' | b'\r') {
+            c += 1;
+        }
+        let val_end = scan_value(b, c)?;
+        if this_key == key {
+            return Some(obj[c..val_end].to_string());
+        }
+        i = val_end;
+    }
+}
+
+/// A string field, JSON-unescaped. `None` if absent or not a string.
+pub fn get_str(obj: &str, key: &str) -> Option<String> {
+    let raw = get_raw(obj, key)?;
+    let inner = raw.strip_prefix('"')?.strip_suffix('"')?;
+    Some(unescape(inner))
+}
+
+/// A numeric field parsed as `T`. Accepts a bare number or a quoted number.
+pub fn get_num<T: std::str::FromStr>(obj: &str, key: &str) -> Option<T> {
+    let raw = get_raw(obj, key)?;
+    raw.trim_matches('"').parse().ok()
+}
+
+/// A boolean field (`true`/`false`, or the strings `"true"`/`"false"`).
+pub fn get_bool(obj: &str, key: &str) -> Option<bool> {
+    match get_raw(obj, key)?.trim_matches('"') {
+        "true" => Some(true),
+        "false" => Some(false),
+        _ => None,
+    }
+}
+
+/// Unescape a JSON string body (the bytes between the quotes).
+fn unescape(s: &str) -> String {
+    if !s.contains('\\') {
+        return s.to_string();
+    }
+    let mut out = String::with_capacity(s.len());
+    let mut it = s.chars();
+    while let Some(c) = it.next() {
+        if c != '\\' {
+            out.push(c);
+            continue;
+        }
+        match it.next() {
+            Some('"') => out.push('"'),
+            Some('\\') => out.push('\\'),
+            Some('/') => out.push('/'),
+            Some('n') => out.push('\n'),
+            Some('r') => out.push('\r'),
+            Some('t') => out.push('\t'),
+            Some('b') => out.push('\u{08}'),
+            Some('f') => out.push('\u{0C}'),
+            Some('u') => {
+                let hex: String = it.by_ref().take(4).collect();
+                if let Some(ch) = u32::from_str_radix(&hex, 16).ok().and_then(char::from_u32) {
+                    out.push(ch);
+                }
+            }
+            Some(other) => out.push(other),
+            None => break,
+        }
+    }
+    out
+}
+
+/// Escape a string for embedding in JSON output (between quotes).
+pub fn esc(s: &str) -> String {
+    let mut out = String::with_capacity(s.len() + 2);
+    for c in s.chars() {
+        match c {
+            '"' => out.push_str("\\\""),
+            '\\' => out.push_str("\\\\"),
+            '\n' => out.push_str("\\n"),
+            '\r' => out.push_str("\\r"),
+            '\t' => out.push_str("\\t"),
+            c if (c as u32) < 0x20 => out.push_str(&format!("\\u{:04x}", c as u32)),
+            c => out.push(c),
+        }
+    }
+    out
+}
+
+/// A JSON object literal from `(key, raw-json-value)` pairs. Values are inserted
+/// verbatim (already valid JSON) — use [`esc`] + quotes for strings.
+pub fn obj(fields: &[(&str, String)]) -> String {
+    let body: Vec<String> = fields.iter().map(|(k, v)| format!("\"{k}\":{v}")).collect();
+    format!("{{{}}}", body.join(","))
+}
+
+/// A quoted, escaped JSON string value from a Rust string.
+pub fn qstr(s: &str) -> String {
+    format!("\"{}\"", esc(s))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn top_level_keys_only() {
+        let o = r#"{"nick":"bob","nested":{"nick":"decoy"},"n":42,"ok":true}"#;
+        assert_eq!(get_str(o, "nick").as_deref(), Some("bob"));
+        assert_eq!(get_num::<i64>(o, "n"), Some(42));
+        assert_eq!(get_bool(o, "ok"), Some(true));
+        assert_eq!(get_raw(o, "nested").as_deref(), Some(r#"{"nick":"decoy"}"#));
+        assert_eq!(get_str(o, "missing"), None);
+    }
+
+    #[test]
+    fn escapes_roundtrip() {
+        let o = r#"{"reason":"a \"quoted\" line\nnext"}"#;
+        assert_eq!(
+            get_str(o, "reason").as_deref(),
+            Some("a \"quoted\" line\nnext")
+        );
+        assert_eq!(esc("a\"b\\c"), "a\\\"b\\\\c");
+    }
+
+    #[test]
+    fn quoted_number_accepted() {
+        assert_eq!(get_num::<u64>(r#"{"d":"3600"}"#, "d"), Some(3600));
+    }
+}

src/modules/rpc/mod.rs

@@ -0,0 +1,119 @@
+//! rpc — a JSON-RPC 2.0 control interface over a small native HTTP server, the
+//! echoIRCd analogue of InspIRCd's `m_httpd` + `m_jsonrpc` + `m_rpc_*`. Admin tools
+//! call it to introspect and drive the ircd (list/kill users, manage bans, rehash…).
+//!
+//! Layering (each provider is its own file, per [[echoircd-module-per-file]]):
+//!   * [`httpd`] — the listener thread: accept, parse HTTP, authenticate, and hand
+//!     the JSON-RPC body to the core as `Event::RpcRequest`.
+//!   * [`json`] — native JSON scan/build (no serde).
+//!   * `core` / `user` / `channel` / `server` / `stats` / `ban` / `message` /
+//!     `whowas` / `spamfilter` / `log` — the method providers, called on the core
+//!     thread with `&mut Server`.
+//!
+//! Security: **off** unless `rpc = yes` AND `rpc_token` is set; binds `rpc_bind`
+//! (default `127.0.0.1:8080`); every request must carry the token (HTTP Basic or
+//! Bearer), checked constant-time on the listener thread before anything dispatches.
+
+pub mod core;
+pub mod httpd;
+pub mod json;
+
+use std::sync::mpsc::Sender;
+
+use crate::config::Config;
+use crate::ircd::Event;
+use crate::server::Server;
+
+/// A JSON-RPC error (standard codes plus app-specific negatives).
+pub struct RpcError {
+    pub code: i64,
+    pub message: String,
+}
+
+impl RpcError {
+    pub fn method_not_found(m: &str) -> RpcError {
+        RpcError {
+            code: -32601,
+            message: format!("Method not found: {m}"),
+        }
+    }
+    pub fn invalid_params(msg: &str) -> RpcError {
+        RpcError {
+            code: -32602,
+            message: msg.to_string(),
+        }
+    }
+    pub fn not_found(msg: &str) -> RpcError {
+        RpcError {
+            code: -1000,
+            message: msg.to_string(),
+        }
+    }
+    pub fn internal(msg: &str) -> RpcError {
+        RpcError {
+            code: -32603,
+            message: msg.to_string(),
+        }
+    }
+}
+
+/// Every method name the interface exposes (drives `rpc.methods`). Keep in sync
+/// with the `dispatch` routes as providers are added.
+pub const ALL_METHODS: &[&str] = &["rpc.methods", "rpc.info", "server.info", "stats.get"];
+
+/// Run a parsed JSON-RPC request on the core thread. `params` is the raw JSON of
+/// the `params` member (`{}` if none); `id` is the raw JSON of the request id
+/// (echoed verbatim). Returns the full JSON-RPC response envelope.
+pub fn dispatch(s: &mut Server, method: &str, _params: &str, id: &str) -> String {
+    // `_params` is consumed once the param-taking providers (user/channel/…) land.
+    let result: Result<String, RpcError> = match method {
+        "rpc.methods" | "rpc.info" => core::rpc_info(s, method),
+        "server.info" | "stats.get" => core::server_info(s),
+        other => Err(RpcError::method_not_found(other)),
+    };
+    envelope(method, id, result)
+}
+
+/// Wrap a provider result (or error) in the JSON-RPC 2.0 response envelope, echoing
+/// the method and id (InspIRCd includes the method in its responses too).
+pub fn envelope(method: &str, id: &str, result: Result<String, RpcError>) -> String {
+    let id = if id.trim().is_empty() { "null" } else { id };
+    match result {
+        Ok(res) => format!(
+            "{{\"jsonrpc\":\"2.0\",\"method\":{},\"result\":{res},\"id\":{id}}}",
+            json::qstr(method)
+        ),
+        Err(e) => format!(
+            "{{\"jsonrpc\":\"2.0\",\"method\":{},\"error\":{{\"code\":{},\"message\":{}}},\"id\":{id}}}",
+            json::qstr(method),
+            e.code,
+            json::qstr(&e.message)
+        ),
+    }
+}
+
+/// Start the RPC HTTP listener if configured. Called from `main` with a clone of
+/// the core's event sender. No-op (with a stderr note) when disabled or misconfigured.
+pub fn maybe_start(cfg: &Config, tx: Sender<Event>) {
+    let get = |k: &str| cfg.raw.get(k).and_then(|v| v.last()).map(|s| s.as_str());
+    let on = get("rpc").map(crate::config::yesish).unwrap_or(false);
+    if !on {
+        return;
+    }
+    let token = match get("rpc_token") {
+        Some(t) if !t.is_empty() => t.to_string(),
+        _ => {
+            eprintln!("echoircd: rpc enabled but no rpc_token set — RPC stays OFF");
+            return;
+        }
+    };
+    let bind = get("rpc_bind").unwrap_or("127.0.0.1:8080").to_string();
+    let user = get("rpc_user").unwrap_or("admin").to_string();
+    match std::net::TcpListener::bind(&bind) {
+        Ok(listener) => {
+            eprintln!("echoircd JSON-RPC on {bind} (token auth)");
+            std::thread::spawn(move || httpd::serve(listener, tx, user, token));
+        }
+        Err(e) => eprintln!("echoircd: cannot bind rpc {bind}: {e}"),
+    }
+}