URL Filter

NVIDIA DOCA URL Filter Application Guide

This document provides a URL filter implementation on top of NVIDIA® BlueField® DPU.

Important:

No updates were made to the DOCA URL Filter application in DOCA 2.2. Please refer to DOCA 2.5 for a note regarding future updates.

URL filtering limits access by comparing web traffic against a database to prevent users from different threats, malware and accessing harmful sites such as phishing pages.

This kind of content filtering can increase network security and enforce policies on different network resources.

URL filter uses Suricata format to create a signature file that can be compiled and loaded to the DPI RegEx engine. The signatures created attempt to find a match in a TCP header’s payload, either inside an HTTP header or an SNI match inside a TLS header. Two different signatures. In terms of packet direction, the match can be both on the sender and receiver. The exact format can be seen in the attached signature file.

URL filtering is designed to run as “bump-on-the-wire” on the BlueField-2 instance. It intercepts traffic coming from the wire and passes it to the physical function (PF) representor connected to the host.

URL filter utilizes the SFT and RegEx engines which are HW accelerators on BlueField.

system-design-diagram.png

  • User adds a URL using the URL command from the CLI. Available commands:
    • Create database – create DB of URLs to be filtered (also removes old signatures)
    • Filter – add specific URL/URL RegEx pattern to be filtered
    • Commit database [PATH] – compile and load signature database
  • Ingress traffic is identified using the connection tracking module
  • Traffic is scanned against compiled signature DB
  • Post-processing is performed for match decision
  • Matched flows are filtered and traffic is blocked


application-architecture-diagram.png

  1. Signatures are compiled by the DPI compiler and are then loaded to the DPI engine.
  2. Ingress traffic is identified and classified using the stateful table module in the DPDK libs which utilizes the connection tracking hardware offloads. This allows flow classifications to be done at the hardware level and forwarded to a hairpin queue without being processed by the software, which increases performance dramatically.
  3. Traffic is scanned against the DPI engine compiled signature DB.
  4. Post-processing is performed for match decision.
  5. Matched flows are identified and can be offloaded to the hardware to increase performance as not further inspection is needed.
  6. Flow termination is done by the aging timer (set in the SFT to 60 seconds). When a flow is offloaded it cannot be tracked and destroyed.
    Note:

    It is important to note that only sites that support non-encrypted HTTP traffic can be matched against signatures created by the URL filtering as it specifically targets the URI field in the HTTP request.

This application leverages the DOCA DPI library.

  1. Parse application argument.
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    doca_argp_init();

    1. Initialize the arg parser resources.
    2. Register DOCA general flags.
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      register_url_params();

    3. Register URL filter application flags.
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      doca_argp_start();

    4. Parse DPDK flags and invoke handler for calling the rte_eal_init() function.
    5. Parse app flags.
  2. DPDK initialization.
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    dpdk_init();

    Calls rte_eal_init() to initialize EAL resources with the provided EAL flags.

  3. DPDK port initialization and start.
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    dpdk_queues_and_ports_init();

    1. Initialize SFT.
    2. Initialize DPDK ports, including mempool allocation.
  4. URL filter initialization.
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    url_filter_init();

    1. Init URL filter resources.
    2. Configure RegEx engine.
    3. Configure DPI queues.
  5. Configure DPI packet processing.
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    dpi_worker_lcores_run();

    1. Configure DPI enqueue packets.
    2. Send jobs to RegEx engine.
    3. Configure DPI dequeue packets.
  6. Add URL shell command
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    initiate_cmdline("URL FILTER>>");

    1. Create database.
    2. Filter http.
    3. Commit database.
  7. DPI destroy
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    url_filter_destroy();

    • Stop DPI worker and free DPI resources
  8. DPDK ports and queues destruction.
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    dpdk_queues_and_ports_fini();

  9. DPDK finish.
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    dpdk_fini();

    calls rte_eal_destroy() to destroy initialized EAL resources.

  10. Arg Parser destroy.
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    doca_argp_destroy();

    • Free DPDK resources

  1. Refer to the following documents:
  2. The URL filtering example binary is located under /opt/mellanox/doca/applications/url_filter/bin/doca_url_filter. To build all the applications together, run:
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    cd /opt/mellanox/doca/applications/ meson build ninja -C build

  3. To build the URL Filter application only:
    1. Edit the following flags in /opt/mellanox/doca/applications/meson_options.txt:
      • Set enable_all_applications to false
      • Set enable_url_filter to true
    2. Run the commands in step 2.
      Note:

      doca_url_filter is created under ./build/url_filter/src/.

    Application usage:

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    Usage: doca_url_filter [DPDK Flags] -- [DOCA Flags] [Program Flags] DOCA Flags: -h, --help Print a help synopsis -v, --version Print program version information -l, --log-level Set the log level for the program <CRITICAL=20, ERROR=30, WARNING=40, INFO=50, DEBUG=60> Program Flags: -p, --print-match Prints FID when matched in DPI engine -f, --fragmented Enables processing fragmented packets -a, --pci-addr DOCA DPI device PCI address

    Note:

    For additional information on available flags for DPDK, use -h before the -- separator:

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    /opt/mellanox/doca/applications/url_filter/bin/doca_url_filter -h

    Note:

    For additional information on the application, use -h after the -- separator:

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    /opt/mellanox/doca/applications/url_filter/bin/doca_url_filter -- -h


  4. Running the application on BlueField:
    • Pre-run setup:
      1. The URL filter example is based on DPDK libraries. Therefore, the user is required to provide DPDK flags, and allocate huge pages.
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        sudo echo 2048 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages

      2. Make sure the RegEx engine is active:
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        systemctl status mlx-regex


        If the status is inactive (Active: failed), run:
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        systemctl start mlx-regex


    • CLI example for running the app:
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      /opt/mellanox/doca/applications/url_filter/bin/doca_url_filter -a auxiliary:mlx5_core.sf.4,sft_en=1 -a auxiliary:mlx5_core.sf.5,sft_en=1 -c3 -- -p -a 03:00.0

      Note:

      The SFT supports a maximum of 64 queues. Therefore, the application cannot be run with more than 64 cores. To limit the number of cores, run:

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      /opt/mellanox/doca/applications/url_filter/bin/doca_url_filter -a auxiliary:mlx5_core.sf.4,sft_en=1 -a auxiliary:mlx5_core.sf.5,sft_en=1 -l 0-64 -- -p -a 03:00.0

      This limits the application to 65 cores (core-0 to core-64) with 1 core for the main thread and 64 cores to serve as workers.

      Note:

      The flags -a auxiliary:mlx5_core.sf.4,sft_en=1 -a auxiliary:mlx5_core.sf.5,sft_en=1 are necessary for proper usage of the application. Modifying them results in unexpected behavior as only 2 ports are supported. The subfunction number is arbitrary and configurable. The RegEx device, however, is not and must be initiated on port 0.

      Note:

      Sub-functions must be enabled according to the Scalable Function Setup Guide.

  5. Running the application on the host, CLI example:
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    /opt/mellanox/doca/applications/url_filter/bin/doca_url_filter -a 05:00.3 -a 05:00.4 -v -- -p -a 05:00.0

    Note:

    Refer to section “Running DOCA Application on Host” in NVIDIA DOCA Virtual Functions User Guide.

    1. To run doca_url_filter using a JSON file:
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      doca_url_filter --json [json_file]

      For example:
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      cd /opt/mellanox/doca/applications/url_filter/bin ./doca_url_filter --json url_params.json


URL Filter is based on user interaction with shell commands. Using the TAB key allows autocompletion while the quit command terminates the application. The following are other available commands:

  • create database – removes and creates a new signature database at /tmp/signature.txt so it can be used in the filter command
  • filter http [msg] [regex] – a signature containing the regular expression written is created in the database. When a match is found, a message is printed.
  • commit database [path] – compiles and loads the signatures created by the filter command from the file path provided. The default database is /tmp/signature.txt.
    Note:

    To load a signatures file that was created beforehand, simply run commit database with the desired path to load the file.

Refer to NVIDIA DOCA Arg Parser Programming Guide for more information.

Flag Type Short Flag Long Flag/JSON Key Description JSON Content
DPDK flags a devices Add a PCIe device into the list of devices to probe
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"devices":[ { "device":"sf", "id":"4", "sft":true }, { "device":"sf", "id":"5", "sft":true } ]

c core-mask Hexadecimal bitmask of cores to run on
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"core-mask": 3

l core-list List of cores to run on
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"core-list": "0-4"

General flags l log-level Sets the log level for the application:
  • CRITICAL=20
  • ERROR=30
  • WARNING=40
  • INFO=50
  • DEBUG=60
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"log-level": 60

v version Print program version information N/A
h help Print a help synopsis N/A
Program flags p print-match Prints FID when matched in DPI engine
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"print-match": true

f fragmented Enables processing of fragmented packets
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"fragmented": false

a pci-addr DOCA DPI device PCIe address.
Note:

This flag is mandatory.

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"pci-addr": "03:00.0"

The URL filter example supports a container-based deployment.

  1. Refer to the NVIDIA DOCA Container Deployment Guide for details on how to deploy a DOCA container to the BlueField.
  2. Notice that the container starts in sleeping mode. That is because of the interactive nature of the URL Filter example app. To run the example, attach to the running container. Run the following:
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    sudo crictl exec -it <container-id> /bin/bash

    Then refer to the entrypoint.sh script at the root directory for an example of how to run the URL filter.

  3. Application-specific configuration steps can be found on NGC, under the application’s container page.

For instructions on running the gRPC application server on the BlueField, refer to NVIDIA DOCA gRPC Infrastructure User Guide.

url-filter-grpc.png

To run the Python client of the gRPC-enabled application:

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./doca_url_filter_gRPC_client.py -d/--debug <server address[:server port]>


For example:

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/opt/mellanox/doca/applications/url_filter/bin/grpc/client/doca_url_filter_gRPC_client.py -d 192.168.104.2

  • /opt/mellanox/doca/applications/url_filter/src
  • /opt/mellanox/doca/applications/url_filter/src/grpc/url_filter.proto

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