Add SMTP server scaffolding

Signed-off-by: Mroik <mroik@delayed.space>

4 files changed, 326 insertions, 0 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 78b6604..48808ba 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3,6 +3,65 @@
 version = 4
 
 [[package]]
+name = "aho-corasick"
+version = "1.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ddd31a130427c27518df266943a5308ed92d4b226cc639f5a8f1002816174301"
+dependencies = [
+ "memchr",
+]
+
+[[package]]
+name = "anstream"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "824a212faf96e9acacdbd09febd34438f8f711fb84e09a8916013cd7815ca28d"
+dependencies = [
+ "anstyle",
+ "anstyle-parse",
+ "anstyle-query",
+ "anstyle-wincon",
+ "colorchoice",
+ "is_terminal_polyfill",
+ "utf8parse",
+]
+
+[[package]]
+name = "anstyle"
+version = "1.0.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "940b3a0ca603d1eade50a4846a2afffd5ef57a9feac2c0e2ec2e14f9ead76000"
+
+[[package]]
+name = "anstyle-parse"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "52ce7f38b242319f7cabaa6813055467063ecdc9d355bbb4ce0c68908cd8130e"
+dependencies = [
+ "utf8parse",
+]
+
+[[package]]
+name = "anstyle-query"
+version = "1.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "40c48f72fd53cd289104fc64099abca73db4166ad86ea0b4341abe65af83dadc"
+dependencies = [
+ "windows-sys",
+]
+
+[[package]]
+name = "anstyle-wincon"
+version = "3.0.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "291e6a250ff86cd4a820112fb8898808a366d8f9f58ce16d1f538353ad55747d"
+dependencies = [
+ "anstyle",
+ "once_cell_polyfill",
+ "windows-sys",
+]
+
+[[package]]
 name = "anyhow"
 version = "1.0.102"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -37,6 +96,35 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9330f8b2ff13f34540b44e946ef35111825727b38d33286ef986142615121801"
 
 [[package]]
+name = "colorchoice"
+version = "1.0.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1d07550c9036bf2ae0c684c4297d503f838287c83c53686d05370d0e139ae570"
+
+[[package]]
+name = "env_filter"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "32e90c2accc4b07a8456ea0debdc2e7587bdd890680d71173a15d4ae604f6eef"
+dependencies = [
+ "log",
+ "regex",
+]
+
+[[package]]
+name = "env_logger"
+version = "0.11.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0621c04f2196ac3f488dd583365b9c09be011a4ab8b9f37248ffcc8f6198b56a"
+dependencies = [
+ "anstream",
+ "anstyle",
+ "env_filter",
+ "jiff",
+ "log",
+]
+
+[[package]]
 name = "fallible-iterator"
 version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -79,6 +167,36 @@ dependencies = [
 ]
 
 [[package]]
+name = "is_terminal_polyfill"
+version = "1.70.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a6cb138bb79a146c1bd460005623e142ef0181e3d0219cb493e02f7d08a35695"
+
+[[package]]
+name = "jiff"
+version = "0.2.23"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1a3546dc96b6d42c5f24902af9e2538e82e39ad350b0c766eb3fbf2d8f3d8359"
+dependencies = [
+ "jiff-static",
+ "log",
+ "portable-atomic",
+ "portable-atomic-util",
+ "serde_core",
+]
+
+[[package]]
+name = "jiff-static"
+version = "0.2.23"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2a8c8b344124222efd714b73bb41f8b5120b27a7cc1c75593a6ff768d9d05aa4"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
 name = "js-sys"
 version = "0.3.93"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -99,23 +217,65 @@ dependencies = [
 ]
 
 [[package]]
+name = "log"
+version = "0.4.29"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5e5032e24019045c762d3c0f28f5b6b8bbf38563a65908389bf7978758920897"
+
+[[package]]
+name = "memchr"
+version = "2.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f8ca58f447f06ed17d5fc4043ce1b10dd205e060fb3ce5b979b8ed8e59ff3f79"
+
+[[package]]
 name = "once_cell"
 version = "1.21.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9f7c3e4beb33f85d45ae3e3a1792185706c8e16d043238c593331cc7cd313b50"
 
 [[package]]
+name = "once_cell_polyfill"
+version = "1.70.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "384b8ab6d37215f3c5301a95a4accb5d64aa607f1fcb26a11b5303878451b4fe"
+
+[[package]]
+name = "pin-project-lite"
+version = "0.2.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a89322df9ebe1c1578d689c92318e070967d1042b512afbe49518723f4e6d5cd"
+
+[[package]]
 name = "pkg-config"
 version = "0.3.32"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7edddbd0b52d732b21ad9a5fab5c704c14cd949e5e9a1ec5929a24fded1b904c"
 
 [[package]]
+name = "portable-atomic"
+version = "1.13.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c33a9471896f1c69cecef8d20cbe2f7accd12527ce60845ff44c153bb2a21b49"
+
+[[package]]
+name = "portable-atomic-util"
+version = "0.2.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "091397be61a01d4be58e7841595bd4bfedb15f1cd54977d79b8271e94ed799a3"
+dependencies = [
+ "portable-atomic",
+]
+
+[[package]]
 name = "poul-list"
 version = "0.1.0"
 dependencies = [
  "anyhow",
+ "env_logger",
+ "log",
  "rusqlite",
+ "tokio",
 ]
 
 [[package]]
@@ -137,6 +297,35 @@ dependencies = [
 ]
 
 [[package]]
+name = "regex"
+version = "1.12.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e10754a14b9137dd7b1e3e5b0493cc9171fdd105e0ab477f51b72e7f3ac0e276"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-automata",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-automata"
+version = "0.4.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6e1dd4122fc1595e8162618945476892eefca7b88c52820e74af6262213cae8f"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-syntax"
+version = "0.8.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dc897dd8d9e8bd1ed8cdad82b5966c3e0ecae09fb1907d58efaa013543185d0a"
+
+[[package]]
 name = "rsqlite-vfs"
 version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -168,6 +357,26 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b39cdef0fa800fc44525c84ccb54a029961a8215f9619753635a9c0d2538d46d"
 
 [[package]]
+name = "serde_core"
+version = "1.0.228"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "41d385c7d4ca58e59fc732af25c3983b67ac852c1a25000afe1175de458b67ad"
+dependencies = [
+ "serde_derive",
+]
+
+[[package]]
+name = "serde_derive"
+version = "1.0.228"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d540f220d3187173da220f885ab66608367b6574e925011a9353e4badda91d79"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
 name = "shlex"
 version = "1.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -223,12 +432,39 @@ dependencies = [
 ]
 
 [[package]]
+name = "tokio"
+version = "1.51.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2bd1c4c0fc4a7ab90fc15ef6daaa3ec3b893f004f915f2392557ed23237820cd"
+dependencies = [
+ "pin-project-lite",
+ "tokio-macros",
+]
+
+[[package]]
+name = "tokio-macros"
+version = "2.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "385a6cb71ab9ab790c5fe8d67f1645e6c450a7ce006a33de03daa956cf70a496"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
 name = "unicode-ident"
 version = "1.0.24"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e6e4313cd5fcd3dad5cafa179702e2b244f760991f45397d14d4ebf38247da75"
 
 [[package]]
+name = "utf8parse"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "06abde3611657adf66d383f00b093d7faecc7fa57071cce2578660c9f1010821"
+
+[[package]]
 name = "vcpkg"
 version = "0.2.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -278,3 +514,18 @@ checksum = "c9bf0406a78f02f336bf1e451799cca198e8acde4ffa278f0fb20487b150a633"
 dependencies = [
  "unicode-ident",
 ]
+
+[[package]]
+name = "windows-link"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f0805222e57f7521d6a62e36fa9163bc891acd422f971defe97d64e70d0a4fe5"
+
+[[package]]
+name = "windows-sys"
+version = "0.61.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ae137229bcbd6cdf0f7b80a31df61766145077ddf49416a728b02cb3921ff3fc"
+dependencies = [
+ "windows-link",
+]
diff --git a/Cargo.toml b/Cargo.toml
index 3504162..c42a1ee 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -5,4 +5,7 @@ edition = "2024"
 
 [dependencies]
 anyhow = "1.0.102"
+env_logger = "0.11.10"
+log = "0.4.29"
 rusqlite = "0.39.0"
+tokio = { version = "1.51.0", features = ["macros", "rt-multi-thread"] }
diff --git a/src/main.rs b/src/main.rs
index 60b75af..075dc7d 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,5 +1,6 @@
 mod database;
 mod list;
+mod smtp;
 
 fn main() {
     println!("Hello, world!");
diff --git a/src/smtp.rs b/src/smtp.rs
new file mode 100644
index 0000000..affac8b
--- /dev/null
+++ b/src/smtp.rs
@@ -0,0 +1,71 @@
+use std::{
+    io::{BufRead, BufReader},
+    net::{IpAddr, SocketAddr, TcpListener, TcpStream},
+};
+
+use anyhow::Result;
+use tokio::spawn;
+
+pub struct SmtpServer {
+    listener: TcpListener,
+    running: bool,
+}
+
+impl SmtpServer {
+    pub fn new(ip: [u8; 4], port: u16) -> Result<Self> {
+        Ok(Self {
+            listener: TcpListener::bind((IpAddr::from(ip), port))?,
+            running: false,
+        })
+    }
+
+    // TODO: trap SIGINT to stop server?
+    pub async fn run(&mut self) -> Result<()> {
+        self.running = true;
+        while self.running {
+            let (stream, addr) = self.listener.accept()?;
+            let session = SessionHandler {
+                stream,
+                addr,
+                state: SessionState::default(),
+            };
+            spawn(session.run());
+        }
+        Ok(())
+    }
+}
+
+struct SessionHandler {
+    stream: TcpStream,
+    addr: SocketAddr,
+    state: SessionState,
+}
+
+impl SessionHandler {
+    async fn run(mut self) -> Result<()> {
+        let mut r = BufReader::new(&self.stream);
+        let mut buffer = String::new();
+
+        loop {
+            if r.read_line(&mut buffer)? == 0 {
+                break;
+            }
+
+            log::debug!("Received '{}' from '{}'", buffer.trim(), self.addr);
+            self.state.apply().await;
+            buffer.clear();
+        }
+
+        log::info!("Connection closed by {}", self.addr);
+        Ok(())
+    }
+}
+
+#[derive(Default)]
+struct SessionState {}
+
+impl SessionState {
+    async fn apply(&mut self) {
+        todo!()
+    }
+}