rusmes-core

Message processing engine for RusMES, implementing the mailet-based pipeline architecture inspired by Apache JAMES.

Architecture

Mail flows through a chain of Matcher-Mailet pairs organized into Processors. A Router dispatches mail to the correct processor based on its current state.

Mail (state=Root)
  |
  v
MailProcessorRouter
  |-- Processor "root" (state=Root)
  |     |-- [AllMatcher] -> SpfCheckMailet
  |     |-- [AllMatcher] -> DkimVerifyMailet
  |     |-- [AllMatcher] -> SpamAssassinMailet
  |     '-- [AllMatcher] -> AddHeaderMailet
  |
  |-- Processor "transport" (state=Transport)
  |     |-- [RecipientIsLocal] -> LocalDeliveryMailet
  |     '-- [All] -> RemoteDeliveryMailet
  |
  '-- Processor "error" (state=Error)
        '-- [All] -> BounceMailet

Modules

Module	Description
`mailet`	`Mailet` trait, `MailetAction`, `MailetConfig`
`matcher`	`Matcher` trait, `AllMatcher`, `NoneMatcher`
`processor`	`Processor` chain, `ProcessingStep`
`router`	`MailProcessorRouter` state-based dispatch
`factory`	`create_mailet()` / `create_matcher()` factory functions
`queue`	`MailQueue` with retry and delay support
`bounce`	Bounce message generation
`rate_limit`	Per-IP connection and message rate limiting
`mailets/`	Standard mailet implementations
`matchers/`	Standard matcher implementations

Mailets (16 implemented)

Mailet	Description
`AddHeader`	Add/modify message headers
`LocalDelivery`	Deliver to local mailboxes
`RemoteDelivery`	Relay to external SMTP servers
`SpamAssassin`	Spam scoring (configurable threshold)
`VirusScan`	Virus detection (stub for ClamAV)
`DkimVerify`	DKIM signature verification (stub)
`SpfCheck`	SPF record validation (stub)
`DmarcVerify`	DMARC alignment check
`Bounce`	Generate DSN bounce messages
`RemoveMimeHeader`	Strip specified MIME headers
`Forward`	Forward mail to additional recipients
`SieveMailet`	Execute Sieve scripts (RFC 5228)
`OxiFYMailet`	AI-powered mail analysis
`LegalisMailet`	Legal archiving integration
`DNSBL`	DNS Blocklist spam prevention
`Greylist`	Greylisting spam prevention

Matchers (11 implemented)

Matcher	Description
`All`	Matches all recipients
`None`	Matches no recipients
`RecipientIsLocal`	Matches recipients in configured local domains
`SenderIs`	Matches by sender address pattern
`HasAttachment`	Matches messages with attachments
`SizeGreaterThan`	Matches messages above a size threshold
`HeaderContains`	Matches by header value pattern
`RemoteAddress`	Matches by client IP / CIDR range
`IsInWhitelist`	Matches senders in whitelist
`IsInBlacklist`	Matches senders in blocklist
`And` / `Or` / `Not`	Composite matchers

Key Traits

#[async_trait]
pub trait Mailet: Send + Sync {
    async fn init(&mut self, config: MailetConfig) -> Result<()>;
    async fn service(&self, mail: &mut Mail) -> Result<MailetAction>;
    async fn destroy(&mut self) -> Result<()>;
    fn name(&self) -> &str;
}

#[async_trait]
pub trait Matcher: Send + Sync {
    async fn match_mail(&self, mail: &Mail) -> Result<Vec<MailAddress>>;
    fn name(&self) -> &str;
}

Dependencies

rusmes-proto - core types
rusmes-storage - storage traits (for LocalDelivery)
rusmes-metrics - metrics collection
tokio - async runtime
tracing - structured logging

Tests

cargo test -p rusmes-core   # 9 tests

rusmes-core 0.1.0