mrzcpd

An internal TSG operations/troubleshooting manual lays out TSG's full traffic pipeline (NIC -> mrzcpd/marsio capture driver -> sapp DPI engine -> firewall/proxy(KNI->TFE)/active-defense/WAN-NAT policy branches) and shows engineers using maat_redis_tool to pull the live Redis-synced blocking policy tables (TSG_SECURITY_COMPILE, TSG_OBJ_IP_ADDR, TSG_OBJ_APP_ID) and filter them by numeric policy/object ID to debug why a block rule isn't firing.

A live tsg_master engine config file exposes a [RESET] section with concrete TCP-RST-injection parameters (NUM=1, SEED1=65535, SEED2=13, FLAGS=20, DIR=3, REMEDY=0), a [TRAFFIC_MIRROR] section confirming mirror-tap deployment (NIC_NAME="eth_vf_mirr"), a [MAAT] section wiring tsg_master directly to MAAT's subscriber-ID tables (TSG_OBJ_SUBSCRIBER_ID/TSG_DYN_SUBSCRIBER_IP), and a device tag "BeiJing-XXG" confirming this specific instance is a domestic Beijing deployment. A plaintext Kafka SASL credential (SASL_PASSWD="galaxy2019") is also exposed, and "galaxy" recurs as an internal project codename elsewhere in this batch (docker service path /home/galaxy, APP_BRIDGE_NAME).

The Xinjiang Mobile carrier traffic report (2023-05-15) states in its own QUIC-domain-ranking section that Xinjiang's intra-provincial traffic has begun carrying QUIC/HTTP3 (UDP-based) traffic that poses "a huge challenge" to the traditional parallel/out-of-band ("并联") traffic-access blocking method, and that effectively gatekeeping ("GK") UDP/QUIC traffic requires switching to an inline/in-path ("串联") blocking architecture — a direct internal admission that (as of mid-2023, in this province) the standard mirror-tap deployment could not reliably block QUIC.

The same SAPP manual documents mrzcpd's inline (串联) packet-re-injection subcomponent mrtunnat, configured at /opt/mrzcpd/etc/mrtunnat.conf: use_recent_tunnel=1 allows it to inject a packet with no prior session record, and use_link_info_table=1 makes it validate outer MAC, link_id, link_dir, and inner MAC against a live link-state table at /run/mrzcpd/mrmonit.tunnat before re-injecting a censor-forged packet onto the correct physical link.

An internal SAPP platform training/reference manual (marked "Geedge Networks Confidential And Proprietary") gives SAPP's full name as "Stream Analyse Process Platform" and documents its three-tier plugin architecture (platform / protocol-parsing / business layers, each loaded via dlopen), inline and mirror deployment modes at a stated 10-40 Gbps per box, tunnel-protocol support (GRE/MPLS/IPIP/IPv6-over-IPv4/Teredo), and the MESA_kill_tcp() plugin API that forges and sends RST packets to sever a monitored TCP connection, with the manual noting it was "originally used in mirror mode to send RST packets to block a TCP connection" and auto-retries until the connection is confirmed dead.

Two 2023 self-test reports (one co-signed by the Institute of Information Engineering, Chinese Academy of Sciences) describe a dedicated capture appliance, hardware model MESA-NF-3100 (2U, Xeon E5-2640V4, 256GB RAM, dual XL710 10GbE NICs, 8Gbps/device and 20-27Gbps/cluster), whose mirror-capture driver is started via `systemctl start mrzpd` (mrzcpd) alongside the sapp process, feeding a downstream 'nirvana_server' component.

An update-alternatives install script for mrzcpd (path /opt/tsg/mrzcpd/...) enumerates its full binary/service set: mrzcpd, mrtools-pinfo, mrpdump (packet dump), monit_stream/monit_device/ monit_obp, mrmarch, dpdk-hugepages.py/dpdk-devbind.py (DPDK NIC binding), and systemd units including mrapm_device/mrapm_stream/mrapm_obp and mrtunnat — confirming mrzcpd is a DPDK-based packet-capture-and-injection agent with a dedicated tunnel/NAT offload component (mrtunnat).

A June 2021 internal report measures a live in-network TLS-interception pilot: one sapp instance ingests raw ciphertext via mrzcpd while a second ingests plaintext from a "third-party decryption platform" over a Unix domain socket, and one hour of production traffic on a live front-end (10.187.0.2) shows the decryption platform successfully produced plaintext for 4.85% of raw traffic bytes and 7.4% of all port-443 TCP connections, with an average end-to-end decrypt latency of 1741ms (median 460ms, up to 6000ms) between first ciphertext byte and the resulting plaintext HTTP GET.

In sapp's inline deployment mode, packet injection is handled by a driver pair (mrzcpd + mrtunnat, an mrzcpd sub-component not previously catalogued) that must reconstruct per-link tunnel state (cached in /run/mrzcpd/mrmonit.tunnat) before forging a packet in the correct direction; the internal troubleshooting guide documents that injection silently fails for GTP/MPLS/GRE-tunneled flows when the reverse-direction tunnel identifier has never been observed on that link, an explicit "asymmetric address layer" edge case.

sapp's internal architecture guide documents three deployment topologies (mirror/passive-tap, inline, dual-arm transparent) and four distinct methods for injecting blocking packets back onto the wire, including a MAC-in-MAC scheme that extracts device/link IDs from mirrored traffic's source MAC field to route an injected packet to the correct physically separate inline device over VXLAN when multiple injection points exist.

The same operations manual's troubleshooting section confirms the blocking system operationally injects forged RST and "spoofed" (欺骗) packets onto mirrored/passive-tap links via network devices — validated by test-injecting a packet via tcpreplay to an external VPS and confirming arrival with tcpdump — runs the sapp process under supervisor scripts with live status/config-version files (TF_maat.status, RESTART.log), and distinguishes a national "GF" system from separate provincial-gateway ("省口") deployments when localizing which egress point a given block should have taken effect at.

TSG ships a built-in offensive "active defense" (主动防御) module named houyi (后羿), built on the sapp/marsio/mrzcpd stack, that performs spoofed-source-IP network-layer flood attacks, DNS/NTP/Memcached reflection-amplification attacks, and application-layer (HTTP/HTTPS) CC floods against a configured target. Spoofed source IPs are drawn from named CIDR-range "profiles" (e.g. 10.1.1.0/24), and policy is distributed via Redis and issued either through an interface called "安天" (Antiy) or by directly calling a "毕方" (Bifang) API. Deployment is via Ansible from git.mesalab.cn/tsg/houyi-deploy, packaged as RPMs installed under /opt/houyi and as sapp plugins under /home/mesasoft/sapp_run/plug.

A "精管流量初步分析报告" (2021-07-26) documents a live paired-sapp TLS-interception testbed: sapp instance A captures raw ciphertext via mrzcpd/PAG while sapp instance B ingests plaintext from a third-party decryption platform over a Unix domain socket. The report measures decryption latency (mean 1.82ms), completeness (only 44% of connections flagged decryptable via an SSL/TLS ClientHello-based "user legitimacy" check were actually decrypted, and 88% of eligible users), and confirms RST-based blocking triggered from the decrypted side reaches the client in a median ~0.5ms and successfully blocked live access to Facebook, Wikipedia, Twitter, the New York Times, and Google (BBC was the one tested site that evaded blocking). The decrypted side also resolves each session to a persistent per-user ID via the ciphertext side's four-tuple lookup.

'mrzcpd' is a real TSG-OS internal service/component (config path /opt/tsg/mrzcpd/etc/mrglobal.conf, tunable poll_wait_throttle_usleep_threshold) involved in packet-drop remediation on Fujian's Quanzhou Unicom site — likely a core packet-processing daemon given the tuning parameter's nature.

An mrzcpd installer script registers a full set of AMD-Zen-optimized ("znver1") binaries and systemd units via update-alternatives — mrzcpd, mrtools-pinfo, mrpdump, monit_stream, monit_device, monit_obp, mrmarch, dpdk-hugepages.py, dpdk-devbind.py, plus services mrapm_device/mrapm_stream/mrapm_obp/mrtunnat/mrzcpd_hugepages_setup/mrzcpd_hwdb_setup — confirming mrzcpd's packet-capture/injection layer is built directly on DPDK with hugepage-backed, CPU-microarchitecture-tuned packet I/O, consistent with the taxonomy's marsio DPDK-framework note.

A leaked Grafana dashboard JSON template ("TSG-X") defines panels querying mrzcpd-exporter Prometheus metrics (rx_drops_total, tx_drops_total, ftx_missed_total, rx_bits_total) keyed per tsg-traffic-engine-vsys service function, confirming mrzcpd (the packet-mirror/inline-injection agent) is operationally monitored for packet loss and throughput as a production Kubernetes/Prometheus-instrumented component of TSG-X deployments.

TSG's data plane runs as containers (firewall, packet-io-engine, proxy, sce, shaping) per TSGX appliance, built on an internal packet framework called Marsio/MRZCPD (config at /opt/tsg/mrzcpd/etc/mrglobal.conf), deployed with 32GB hugepages and tunable TX rate-limiting per bonded NIC.

An official "Geedge Networks Confidential And Proprietary" sapp/mrzcpd operations manual documents the packet-injection API (MESA_kill_tcp / MESA_inject_pkt) used for both out-of-band mirror-tap RST injection (relies on the local box's own IP routing table to send) and inline in-path injection (requires mrtunnat.conf tunnel-tracking state -- use_recent_tunnel, use_link_info_table -- keyed on outer/inner MAC and link_id/link_dir), plus the Marsio DPDK-based driver's I/O sub-modes (marsio4, marsio_vxlan, pag_marsio, agent_smith) and its role extracting VXLAN/GTP encapsulation metadata and stamping link/circuit identifiers into mirrored packets' MAC field for session-log correlation.

TSG's RST-injection blocking pipeline is architecturally split: mrzcpd (packet-mirror/capture agent) batches packets (config sz_buffer, packets-per-forward) before handing them to sapp (the inspection/policy engine) for match-and-RST. Under certain carrier/traffic conditions this batching introduced a 5-20ms delay between the real SYN and sapp's RST, letting the blocked connection's data through before the RST arrived -- a confirmed, reproducible bypass ('穿透') on specific Fujian ISP links, fixed only by setting sz_buffer to 0 (no batching).

Confirms a TSG-X/TSG-OS (v22.11) deployment at "新疆联通IDC" (Xinjiang Unicom IDC, a specific China Unicom data center), part of a domestic "XJ-NPM" project; core traffic-processing components are named "mrzcpd" and "sapp," both required to start successfully for the appliance to function.

SAPP's packet-capture configuration parameter (capdatamodlel) documents up to 16 capture-driver modes including libpcap, PF_RING, and DPDK, plus a Geedge-proprietary "marsio" mode (value 12) built by MESA on top of DPDK, whose driver-specific configuration is explicitly stated to live at /opt/mrzcpd/etc -- confirming, from SAPP's own configuration documentation, the marsio-mrzcpd relationship already inferred elsewhere in the corpus.

SAPP's internal developer manual documents three generic "packet-send" interfaces exposed to every business plugin: MESA_kill_tcp (builds and sends a TCP RST matching the current flow's four-tuple/sequence numbers to forcibly terminate a connection), MESA_kill_tcp_synack (sends a forged SYN/ACK so the client can never complete a handshake with the real server), and MESA_inject_pkt (injects arbitrary application-layer payload toward either side of a flow). This confirms RST-injection and payload-injection are first-class, reusable platform primitives, not one-off code, and that mrzcpd is the mechanism that re-injects sapp-generated blocking packets into a mirrored/passive-tap link (consistent with taxonomy.yaml's mrzcpd note).

Primary-source MESA Lab wiki documentation confirms SAPP ("Stream Analyse Process Platform") is a plugin-based traffic-inspection engine achieving 10-40Gbps per hardware unit, deployable either inline (串联) or as a passive mirror tap (并联), and exposes core platform APIs available to any business-layer plugin for forging a TCP RST (MESA_kill_tcp), spoofing a fake SYN/ACK to block connection establishment (MESA_kill_tcp_synack), and injecting arbitrary application-layer data into an established flow (MESA_inject_pkt).

A June 2021 MESA Lab test report ("精管流量初步分析报告") measured a live TLS-decryption pipeline feeding two sapp instances -- sapp A ingesting raw encrypted traffic via mrzcpd, sapp B ingesting plaintext from a third-party decryption platform over a Unix domain socket -- and found decrypted plaintext covered only 4.85% of raw traffic bytes and 7.4% of port-443 connections, with average MITM decryption latency of 1741ms (range 158-6000ms) across 2957 matched connections.

The lirenjie/lrj_vxlan sapp-plugin repo (2019-2020) implements a mirror/re-inject packet-processing plugin for VXLAN-encapsulated traffic that defaults to DROP for all packets and explicitly distinguishes two traffic-handling modes, "回流" (return-flow/mirror-received) and "回注" (re-inject), consistent with the mrzcpd/marsio architecture where sapp's blocking decisions on mirrored traffic are re-injected into the link.

'tcpdump_mesa' (Geedge's tcpdump fork, packaged as an RPM dependency of the sapp DPI role) adds a '-g' greedy-jump mode that filters and captures by the innermost IP/port inside tunneled/encapsulated traffic (coordinated with sapp over a control connection), and can capture packets sapp routes around DDoS-bypass handling -- confirming TSG's packet-capture tooling is explicitly built to see through tunnel encapsulation rather than only inspecting the outer transport.

The tango/tsg-service-chaining-engine (SCE) repo implements TSG's traffic-steering core: it VXLAN-encapsulates and routes both "raw" and "decrypted" copies of a session (four tracked metadata directions) through a chain of up to 32 third-party "Service Functions", with explicit per-flow actions of block, bypass, forward, and rx_drop for both mirrored and inline-steered traffic, coordinating with SAPP, mrzcpd (packet capture/re-injection), and MAAT4 (rule engine) via control-plane messages.

Geedge's production inline-deployment container bundle (tango/tsg_container) wires mrzcpd (capture/inject), sapp (DPI via maat rules), and a third component "tfe" (traffic-forwarding engine) together via Docker Compose; tfe ships a dedicated doh.conf (DNS-over-HTTPS handling) and the firewall-mode container's sapp config includes a send_raw_pkt.conf, a KNI (kernel network interface) config, an "asymmetric_presence_layer.conf" for mirror/asymmetric-routing deployments, and a "pangu" proxy module (pangu_pxy.conf / pangu_http.json).

TSG's Ansible deployment platform ('tsg/tsg-scripts-platform') installs per-protocol firewall RPM modules -- dedicated dns, ftp, http, mail, quic, and ssl packages -- alongside the sapp DPI engine and mrzcpd packet-mirror/inject agent, confirming TSG ships a purpose-built QUIC/HTTP3 blocking module as a first-class protocol-firewall component.