40. IPsec Security Gateway Sample Application

40.1. Overview

The application demonstrates the implementation of a Security Gateway (not IPsec compliant, see the Constraints section below) using DPDK based on RFC4301, RFC4303, RFC3602 and RFC2404.

Internet Key Exchange (IKE) is not implemented, so only manual setting of Security Policies and Security Associations is supported.

The Security Policies (SP) are implemented as ACL rules, the Security Associations (SA) are stored in a table and the routing is implemented using LPM.

The application classifies the ports as Protected and Unprotected. Thus, traffic received on an Unprotected or Protected port is consider Inbound or Outbound respectively.

The Path for IPsec Inbound traffic is:

• Read packets from the port.
• Classify packets between IPv4 and ESP.
• Perform Inbound SA lookup for ESP packets based on their SPI.
• Perform Verification/Decryption.
• Remove ESP and outer IP header
• Inbound SP check using ACL of decrypted packets and any other IPv4 packets.
• Routing.
• Write packet to port.

The Path for the IPsec Outbound traffic is:

• Read packets from the port.
• Perform Outbound SP check using ACL of all IPv4 traffic.
• Perform Outbound SA lookup for packets that need IPsec protection.
• Add ESP and outer IP header.
• Perform Encryption/Digest.
• Routing.
• Write packet to port.

40.2. Constraints

• No IPv6 options headers.
• No AH mode.
• Supported algorithms: AES-CBC, AES-CTR, AES-GCM, HMAC-SHA1 and NULL.
• Each SA must be handle by a unique lcore (1 RX queue per port).
• No chained mbufs.

40.3. Compiling the Application

To compile the application:

1. Go to the sample application directory:

   export RTE_SDK=/path/to/rte_sdk
   cd ${RTE_SDK}/examples/ipsec-secgw
   

2. Set the target (a default target is used if not specified). For example:

   export RTE_TARGET=x86_64-native-linuxapp-gcc
   

   See the DPDK Getting Started Guide for possible RTE_TARGET values.

3. Build the application:

   make
   

4. [Optional] Build the application for debugging: This option adds some extra flags, disables compiler optimizations and is verbose:

   make DEBUG=1
   

40.4. Running the Application

The application has a number of command line options:

./build/ipsec-secgw [EAL options] --
                     -p PORTMASK -P -u PORTMASK
                     --config (port,queue,lcore)[,(port,queue,lcore]
                     --single-sa SAIDX
                     -f CONFIG_FILE_PATH

Where:

• -p PORTMASK: Hexadecimal bitmask of ports to configure.
• -P: optional. Sets all ports to promiscuous mode so that packets are accepted regardless of the packet’s Ethernet MAC destination address. Without this option, only packets with the Ethernet MAC destination address set to the Ethernet address of the port are accepted (default is enabled).
• -u PORTMASK: hexadecimal bitmask of unprotected ports
• --config (port,queue,lcore)[,(port,queue,lcore)]: determines which queues from which ports are mapped to which cores.
• --single-sa SAIDX: use a single SA for outbound traffic, bypassing the SP on both Inbound and Outbound. This option is meant for debugging/performance purposes.
• -f CONFIG_FILE_PATH: the full path of text-based file containing all configuration items for running the application (See Configuration file syntax section below). -f CONFIG_FILE_PATH must be specified. ONLY the UNIX format configuration file is accepted.

The mapping of lcores to port/queues is similar to other l3fwd applications.

For example, given the following command line:

./build/ipsec-secgw -l 20,21 -n 4 --socket-mem 0,2048       \
       --vdev "cryptodev_null_pmd" -- -p 0xf -P -u 0x3      \
       --config="(0,0,20),(1,0,20),(2,0,21),(3,0,21)"       \
       -f /path/to/config_file                              \

where each options means:

• The -l option enables cores 20 and 21.

• The -n option sets memory 4 channels.

• The --socket-mem to use 2GB on socket 1.

• The --vdev "cryptodev_null_pmd" option creates virtual NULL cryptodev PMD.

• The -p option enables ports (detected) 0, 1, 2 and 3.

• The -P option enables promiscuous mode.

• The -u option sets ports 1 and 2 as unprotected, leaving 2 and 3 as protected.

• The --config option enables one queue per port with the following mapping:

  Port	Queue	lcore	Description
  0	0	20	Map queue 0 from port 0 to lcore 20.
  1	0	20	Map queue 0 from port 1 to lcore 20.
  2	0	21	Map queue 0 from port 2 to lcore 21.
  3	0	21	Map queue 0 from port 3 to lcore 21.

• The -f /path/to/config_file option enables the application read and parse the configuration file specified, and configures the application with a given set of SP, SA and Routing entries accordingly. The syntax of the configuration file will be explained below in more detail. Please note the parser only accepts UNIX format text file. Other formats such as DOS/MAC format will cause a parse error.

Refer to the DPDK Getting Started Guide for general information on running applications and the Environment Abstraction Layer (EAL) options.

The application would do a best effort to “map” crypto devices to cores, with hardware devices having priority. Basically, hardware devices if present would be assigned to a core before software ones. This means that if the application is using a single core and both hardware and software crypto devices are detected, hardware devices will be used.

A way to achieve the case where you want to force the use of virtual crypto devices is to whitelist the Ethernet devices needed and therefore implicitly blacklisting all hardware crypto devices.

For example, something like the following command line:

./build/ipsec-secgw -l 20,21 -n 4 --socket-mem 0,2048 \
        -w 81:00.0 -w 81:00.1 -w 81:00.2 -w 81:00.3 \
        --vdev "cryptodev_aesni_mb_pmd" --vdev "cryptodev_null_pmd" \
        -- \
        -p 0xf -P -u 0x3 --config="(0,0,20),(1,0,20),(2,0,21),(3,0,21)" \
        -f sample.cfg

40.5. Configurations

The following sections provide the syntax of configurations to initialize your SP, SA and Routing tables. Configurations shall be specified in the configuration file to be passed to the application. The file is then parsed by the application. The successful parsing will result in the appropriate rules being applied to the tables accordingly.

sp <ip_ver> <dir> esp <action> <priority> <src_ip> <dst_ip>
<proto> <sport> <dport>

sp ipv4 out esp protect 105 pri 1 dst 192.168.115.0/24 sport 0:65535 \
dport 0:65535

sp ipv6 in esp bypass pri 1 dst 0000:0000:0000:0000:5555:5555:\
0000:0000/96 sport 0:65535 dport 0:65535

sa <dir> <spi> <cipher_algo> <cipher_key> <auth_algo> <auth_key>
<mode> <src_ip> <dst_ip>

sa out 5 cipher_algo null auth_algo null mode ipv4-tunnel \
src 172.16.1.5 dst 172.16.2.5

sa out 25 cipher_algo aes-128-cbc \
cipher_key c3:c3:c3:c3:c3:c3:c3:c3:c3:c3:c3:c3:c3:c3:c3:c3 \
auth_algo sha1-hmac \
auth_key c3:c3:c3:c3:c3:c3:c3:c3:c3:c3:c3:c3:c3:c3:c3:c3:c3:c3:c3:c3 \
mode ipv6-tunnel \
src 1111:1111:1111:1111:1111:1111:1111:5555 \
dst 2222:2222:2222:2222:2222:2222:2222:5555

sa in 105 cipher_algo aes-128-gcm \
cipher_key de:ad:be:ef:de:ad:be:ef:de:ad:be:ef:de:ad:be:ef:de:ad:be:ef \
auth_algo aes-128-gcm \
mode ipv4-tunnel src 172.16.2.5 dst 172.16.1.5

rt <ip_ver> <src_ip> <dst_ip> <port>

rt ipv4 dst 172.16.1.5/32 port 0

rt ipv6 dst 1111:1111:1111:1111:1111:1111:1111:5555/116 port 0