Throttling / bandwidth shaping

pg_valve_deal.cpp / pg_valve_main.cpp source shows the 'valve' (pangu_valve) component implements a MAAT-fed, hierarchical (region/group -> dataset -> domain-ID) rule-dispatch engine: each incoming rule line carries a keyword field plus expr_type/match_method/is_hexbin matching flags, an ADD/DEL action, and a percentage-based 'Droprate' throttle parsed out of a semicolon-delimited region string (DOMAIN_ID=...;config_id=...;Droprate=...) — i.e. a keyword/domain-based engine that can partially throttle traffic, not just binary-block it.

TSG's QA automation framework (dongxiaoyan/gap_tsg_api) documents the policy engine's app-blocking action taxonomy (default/Drop/RateLimit/Tamper, with "rst" later renamed "reset") and records that, as of a 2022 test-suite update, the circumvention tools Psiphon ("赛风") and Freegate ("自由门") were only supported under a RateLimit (throttle) deny action rather than a hard Drop, while dozens of other apps (WeChat, Telegram, WhatsApp, Tor, WireGuard, TachyonVPN, Instagram, Facebook, etc.) had named test coverage across Allow/Deny/Monitor actions.

The PanGu/pangu_valve repo implements MAAT's live blocking/throttling distribution layer: it consumes Redis-backed MAAT config tables (APP_DOMAIN, APP_POLICY, LIMIT_DOMAIN, APP_STATIC_SEV_IP, APP_DYN_SEV_IP_CB, LIMIT_DYN_IP_CB) and pushes reference-counted domain/IP block and rate-limit rules to inline ("串联设备") network devices, scoped per inline-device business ID.

TSG's "shaping-engine" (tango/shaping-engine) implements bandwidth-shaping "Profiles" (fair-share token allocation, priority-based bandwidth borrowing, active queue management) driven by rules loaded directly from MAAT (shaper_maat.cpp/h, shaping_maat.json, migrated to MAAT's JSON rule format with UUID rule IDs), providing the likely underlying enforcement mechanism behind app-specific RateLimit deny actions such as the Psiphon/Freegate throttling documented in gap_tsg_api.

swarmkv is an internally-built, CRDT-based distributed key-value store (Redis-like, with Bloom filter, HyperLogLog, Count-Min Sketch, and token-bucket data types) referenced directly by TSG ticket numbers (TSG-20539, TSG-21840, TSG-15595) for its Committed-Information-Rate/Committed-Burst-Size (CIR/CBS) token-bucket throttling — the distributed state layer backing TSG's cluster-wide rate-limit/throttling policy actions.

TSG-OS has a configurable 'overload bypass' mode (tsg-os-cli: set template name tsg_traffic_engine_default overload_protection enable yes) that, per Geedge support guidance to a customer experiencing packet drops, is a standard remediation for performance issues under peak load — implying traffic can be configured to bypass full processing when the appliance is overloaded.

TSG's policy-API test suite (zhaokun/tsg_policy_api, 508 commits) enumerates the full deny-action taxonomy exercised against combinations of IP/SNI/APP/flag match conditions and negation: deny_alert (HTTP 200 with profile or text body), deny_block (403/404 with profile or text), deny_drop, deny_noreset, deny_redirect (DNS with 1-3 forged answers), and deny_rate_limit (high/low), plus "allow" and "shunt" (traffic-diversion) actions — a precise map of TSG's blocking/throttling/redirect action space.