xref: /dpdk/doc/guides/sample_app_ug/ip_frag.rst (revision fea1d908d39989a27890b29b5c0ec94c85c8257b)
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31IP Fragmentation Sample Application
32===================================
33
34The IPv4 Fragmentation application is a simple example of packet processing
35using the Data Plane Development Kit (DPDK).
36The application does L3 forwarding with IPv4 and IPv6 packet fragmentation.
37
38Overview
39--------
40
41The application demonstrates the use of zero-copy buffers for packet fragmentation.
42The initialization and run-time paths are very similar to those of the L2 forwarding application
43(see Chapter 9 "L2 Forwarding Simple Application (in Real and Virtualized Environments)" for more information).
44This guide highlights the differences between the two applications.
45
46There are three key differences from the L2 Forwarding sample application:
47
48*   The first difference is that the IP Fragmentation sample application makes use of indirect buffers.
49
50*   The second difference is that the forwarding decision is taken
51    based on information read from the input packet's IP header.
52
53*   The third difference is that the application differentiates between
54    IP and non-IP traffic by means of offload flags.
55
56The Longest Prefix Match (LPM for IPv4, LPM6 for IPv6) table is used to store/lookup an outgoing port number,
57associated with that IP address.
58Any unmatched packets are forwarded to the originating port.
59
60By default, input frame sizes up to 9.5 KB are supported.
61Before forwarding, the input IP packet is fragmented to fit into the "standard" Ethernet* v2 MTU (1500 bytes).
62
63Building the Application
64------------------------
65
66To build the application:
67
68#.  Go to the sample application directory:
69
70    .. code-block:: console
71
72        export RTE_SDK=/path/to/rte_sdk
73        cd ${RTE_SDK}/examples/ip_fragmentation
74
75#.  Set the target (a default target is used if not specified). For example:
76
77    .. code-block:: console
78
79        export RTE_TARGET=x86_64-native-linuxapp-gcc
80
81See the *DPDK Getting Started Guide* for possible RTE_TARGET values.
82
83#.  Build the application:
84
85    .. code-block:: console
86
87        make
88
89Running the Application
90-----------------------
91
92The LPM object is created and loaded with the pre-configured entries read from
93global l3fwd_ipv4_route_array and l3fwd_ipv6_route_array tables.
94For each input packet, the packet forwarding decision
95(that is, the identification of the output interface for the packet) is taken as a result of LPM lookup.
96If the IP packet size is greater than default output MTU,
97then the input packet is fragmented and several fragments are sent via the output interface.
98
99Application usage:
100
101.. code-block:: console
102
103    ./build/ip_fragmentation [EAL options] -- -p PORTMASK [-q NQ]
104
105where:
106
107*   -p PORTMASK is a hexadecimal bitmask of ports to configure
108
109*   -q NQ is the number of queue (=ports) per lcore (the default is 1)
110
111To run the example in linuxapp environment with 2 lcores (2,4) over 2 ports(0,2) with 1 RX queue per lcore:
112
113.. code-block:: console
114
115    ./build/ip_fragmentation -c 0x14 -n 3 -- -p 5
116    EAL: coremask set to 14
117    EAL: Detected lcore 0 on socket 0
118    EAL: Detected lcore 1 on socket 1
119    EAL: Detected lcore 2 on socket 0
120    EAL: Detected lcore 3 on socket 1
121    EAL: Detected lcore 4 on socket 0
122    ...
123
124    Initializing port 0 on lcore 2... Address:00:1B:21:76:FA:2C, rxq=0 txq=2,0 txq=4,1
125    done: Link Up - speed 10000 Mbps - full-duplex
126    Skipping disabled port 1
127    Initializing port 2 on lcore 4... Address:00:1B:21:5C:FF:54, rxq=0 txq=2,0 txq=4,1
128    done: Link Up - speed 10000 Mbps - full-duplex
129    Skipping disabled port 3IP_FRAG: Socket 0: adding route 100.10.0.0/16 (port 0)
130    IP_FRAG: Socket 0: adding route 100.20.0.0/16 (port 1)
131    ...
132    IP_FRAG: Socket 0: adding route 0101:0101:0101:0101:0101:0101:0101:0101/48 (port 0)
133    IP_FRAG: Socket 0: adding route 0201:0101:0101:0101:0101:0101:0101:0101/48 (port 1)
134    ...
135    IP_FRAG: entering main loop on lcore 4
136    IP_FRAG: -- lcoreid=4 portid=2
137    IP_FRAG: entering main loop on lcore 2
138    IP_FRAG: -- lcoreid=2 portid=0
139
140To run the example in linuxapp environment with 1 lcore (4) over 2 ports(0,2) with 2 RX queues per lcore:
141
142.. code-block:: console
143
144    ./build/ip_fragmentation -c 0x10 -n 3 -- -p 5 -q 2
145
146To test the application, flows should be set up in the flow generator that match the values in the
147l3fwd_ipv4_route_array and/or l3fwd_ipv6_route_array table.
148
149The default l3fwd_ipv4_route_array table is:
150
151.. code-block:: c
152
153    struct l3fwd_ipv4_route l3fwd_ipv4_route_array[] = {
154        {IPv4(100, 10, 0, 0), 16, 0},
155        {IPv4(100, 20, 0, 0), 16, 1},
156        {IPv4(100, 30, 0, 0), 16, 2},
157        {IPv4(100, 40, 0, 0), 16, 3},
158        {IPv4(100, 50, 0, 0), 16, 4},
159        {IPv4(100, 60, 0, 0), 16, 5},
160        {IPv4(100, 70, 0, 0), 16, 6},
161        {IPv4(100, 80, 0, 0), 16, 7},
162    };
163
164The default l3fwd_ipv6_route_array table is:
165
166.. code-block:: c
167
168    struct l3fwd_ipv6_route l3fwd_ipv6_route_array[] = {
169        {{1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, 48, 0},
170        {{2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, 48, 1},
171        {{3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, 48, 2},
172        {{4, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, 48, 3},
173        {{5, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, 48, 4},
174        {{6, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, 48, 5},
175        {{7, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, 48, 6},
176        {{8, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, 48, 7},
177    };
178
179For example, for the input IPv4 packet with destination address: 100.10.1.1 and packet length 9198 bytes,
180seven IPv4 packets will be sent out from port #0 to the destination address 100.10.1.1:
181six of those packets will have length 1500 bytes and one packet will have length 318 bytes.
182IP Fragmentation sample application provides basic NUMA support
183in that all the memory structures are allocated on all sockets that have active lcores on them.
184
185
186Refer to the *DPDK Getting Started Guide* for general information on running applications
187and the Environment Abstraction Layer (EAL) options.
188