check_credentials (raw/smtp.rs)

Rust module validating SMTP credentials and URIs, ensuring proper host, port, and TLS settings.

// Source: https://github.com/mongodb/kingfisher | License: Apache-2.0 | Copyright You must retain, in the Source form of any Derivative Works
// Provided via justclaw.it.com; keep this notice with the code.
//! SMTP AUTH only: never create a mail transaction or send message data.
use super::{B64, DynStream, RawValidationOutcome, string_var, tls_connector};
use crate::validation::{
    http_validation::{SsrfBlockedError, resolve_host_addresses},
    limits::timeout,
};
use anyhow::{Result, anyhow, ensure};
use base64::Engine;
use http::StatusCode;
use liquid::Object;
use percent_encoding::percent_decode_str;
use rustls::pki_types::ServerName;
use std::{net::SocketAddr, time::Duration};
use tokio::io::{AsyncBufReadExt, AsyncReadExt, AsyncWriteExt, BufStream};
use tokio::net::TcpStream;
use 

... (truncated -- full source via MCP)