--- /dev/null
+.. BSD LICENSE
+ Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
+ All rights reserved.
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions
+ are met:
+
+ * Redistributions of source code must retain the above copyright
+ notice, this list of conditions and the following disclaimer.
+ * Redistributions in binary form must reproduce the above copyright
+ notice, this list of conditions and the following disclaimer in
+ the documentation and/or other materials provided with the
+ distribution.
+ * Neither the name of Intel Corporation nor the names of its
+ contributors may be used to endorse or promote products derived
+ from this software without specific prior written permission.
+
+ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+IP Reassembly Sample Application
+================================
+
+The L3 Forwarding application is a simple example of packet processing using the DPDK.
+The application performs L3 forwarding with reassembly for fragmented IPv4 and IPv6 packets.
+
+Overview
+--------
+
+The application demonstrates the use of the DPDK libraries to implement packet forwarding
+with reassembly for IPv4 and IPv6 fragmented packets.
+The initialization and run- time paths are very similar to those of the :doc:`l2_forward_real_virtual`.
+The main difference from the L2 Forwarding sample application is that
+it reassembles fragmented IPv4 and IPv6 packets before forwarding.
+The maximum allowed size of reassembled packet is 9.5 KB.
+
+There are two key differences from the L2 Forwarding sample application:
+
+* The first difference is that the forwarding decision is taken based on information read from the input packet's IP header.
+
+* The second difference is that the application differentiates between IP and non-IP traffic by means of offload flags.
+
+The Longest Prefix Match (LPM for IPv4, LPM6 for IPv6) table is used to store/lookup an outgoing port number, associated with that IPv4 address. Any unmatched packets are forwarded to the originating port.Compiling the Application
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+
+To compile the application:
+
+#. Go to the sample application directory:
+
+ .. code-block:: console
+
+ export RTE_SDK=/path/to/rte_sdk
+ cd ${RTE_SDK}/examples/ip_reassembly
+
+#. Set the target (a default target is used if not specified). For example:
+
+ .. code-block:: console
+
+ export RTE_TARGET=x86_64-native-linuxapp-gcc
+
+See the *DPDK Getting Started Guide* for possible RTE_TARGET values.
+
+#. Build the application:
+
+ .. code-block:: console
+
+ make
+
+Running the Application
+-----------------------
+
+The application has a number of command line options:
+
+.. code-block:: console
+
+ ./build/ip_reassembly [EAL options] -- -p PORTMASK [-q NQ] [--maxflows=FLOWS>] [--flowttl=TTL[(s|ms)]]
+
+where:
+
+* -p PORTMASK: Hexadecimal bitmask of ports to configure
+
+* -q NQ: Number of RX queues per lcore
+
+* --maxflows=FLOWS: determines maximum number of active fragmented flows (1-65535). Default value: 4096.
+
+* --flowttl=TTL[(s|ms)]: determines maximum Time To Live for fragmented packet.
+ If all fragments of the packet wouldn't appear within given time-out,
+ then they are considered as invalid and will be dropped.
+ Valid range is 1ms - 3600s. Default value: 1s.
+
+To run the example in linuxapp environment with 2 lcores (2,4) over 2 ports(0,2) with 1 RX queue per lcore:
+
+.. code-block:: console
+
+ ./build/ip_reassembly -c 0x14 -n 3 -- -p 5
+ EAL: coremask set to 14
+ EAL: Detected lcore 0 on socket 0
+ EAL: Detected lcore 1 on socket 1
+ EAL: Detected lcore 2 on socket 0
+ EAL: Detected lcore 3 on socket 1
+ EAL: Detected lcore 4 on socket 0
+ ...
+
+ Initializing port 0 on lcore 2... Address:00:1B:21:76:FA:2C, rxq=0 txq=2,0 txq=4,1
+ done: Link Up - speed 10000 Mbps - full-duplex
+ Skipping disabled port 1
+ Initializing port 2 on lcore 4... Address:00:1B:21:5C:FF:54, rxq=0 txq=2,0 txq=4,1
+ done: Link Up - speed 10000 Mbps - full-duplex
+ Skipping disabled port 3IP_FRAG: Socket 0: adding route 100.10.0.0/16 (port 0)
+ IP_RSMBL: Socket 0: adding route 100.20.0.0/16 (port 1)
+ ...
+
+ IP_RSMBL: Socket 0: adding route 0101:0101:0101:0101:0101:0101:0101:0101/48 (port 0)
+ IP_RSMBL: Socket 0: adding route 0201:0101:0101:0101:0101:0101:0101:0101/48 (port 1)
+ ...
+
+ IP_RSMBL: entering main loop on lcore 4
+ IP_RSMBL: -- lcoreid=4 portid=2
+ IP_RSMBL: entering main loop on lcore 2
+ IP_RSMBL: -- lcoreid=2 portid=0
+
+To run the example in linuxapp environment with 1 lcore (4) over 2 ports(0,2) with 2 RX queues per lcore:
+
+.. code-block:: console
+
+ ./build/ip_reassembly -c 0x10 -n 3 -- -p 5 -q 2
+
+To test the application, flows should be set up in the flow generator that match the values in the
+l3fwd_ipv4_route_array and/or l3fwd_ipv6_route_array table.
+
+Please note that in order to test this application,
+the traffic generator should be generating valid fragmented IP packets.
+For IPv6, the only supported case is when no other extension headers other than
+fragment extension header are present in the packet.
+
+The default l3fwd_ipv4_route_array table is:
+
+.. code-block:: c
+
+ struct l3fwd_ipv4_route l3fwd_ipv4_route_array[] = {
+ {IPv4(100, 10, 0, 0), 16, 0},
+ {IPv4(100, 20, 0, 0), 16, 1},
+ {IPv4(100, 30, 0, 0), 16, 2},
+ {IPv4(100, 40, 0, 0), 16, 3},
+ {IPv4(100, 50, 0, 0), 16, 4},
+ {IPv4(100, 60, 0, 0), 16, 5},
+ {IPv4(100, 70, 0, 0), 16, 6},
+ {IPv4(100, 80, 0, 0), 16, 7},
+ };
+
+The default l3fwd_ipv6_route_array table is:
+
+.. code-block:: c
+
+ struct l3fwd_ipv6_route l3fwd_ipv6_route_array[] = {
+ {{1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, 48, 0},
+ {{2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, 48, 1},
+ {{3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, 48, 2},
+ {{4, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, 48, 3},
+ {{5, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, 48, 4},
+ {{6, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, 48, 5},
+ {{7, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, 48, 6},
+ {{8, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, 48, 7},
+ };
+
+For example, for the fragmented input IPv4 packet with destination address: 100.10.1.1,
+a reassembled IPv4 packet be sent out from port #0 to the destination address 100.10.1.1
+once all the fragments are collected.
+
+Explanation
+-----------
+
+The following sections provide some explanation of the sample application code.
+As mentioned in the overview section, the initialization and run-time paths are very similar to those of the :doc:`l2_forward_real_virtual`.
+The following sections describe aspects that are specific to the IP reassemble sample application.
+
+IPv4 Fragment Table Initialization
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+This application uses the rte_ip_frag library. Please refer to Programmer's Guide for more detailed explanation of how to use this library.
+Fragment table maintains information about already received fragments of the packet.
+Each IP packet is uniquely identified by triple <Source IP address>, <Destination IP address>, <ID>.
+To avoid lock contention, each RX queue has its own Fragment Table,
+e.g. the application can't handle the situation when different fragments of the same packet arrive through different RX queues.
+Each table entry can hold information about packet consisting of up to RTE_LIBRTE_IP_FRAG_MAX_FRAGS fragments.
+
+.. code-block:: c
+
+ frag_cycles = (rte_get_tsc_hz() + MS_PER_S - 1) / MS_PER_S * max_flow_ttl;
+
+ if ((qconf->frag_tbl[queue] = rte_ip_frag_tbl_create(max_flow_num, IPV4_FRAG_TBL_BUCKET_ENTRIES, max_flow_num, frag_cycles, socket)) == NULL)
+ {
+ RTE_LOG(ERR, IP_RSMBL, "ip_frag_tbl_create(%u) on " "lcore: %u for queue: %u failed\n", max_flow_num, lcore, queue);
+ return -1;
+ }
+
+Mempools Initialization
+~~~~~~~~~~~~~~~~~~~~~~~
+
+The reassembly application demands a lot of mbuf's to be allocated.
+At any given time up to (2 \* max_flow_num \* RTE_LIBRTE_IP_FRAG_MAX_FRAGS \* <maximum number of mbufs per packet>)
+can be stored inside Fragment Table waiting for remaining fragments.
+To keep mempool size under reasonable limits and to avoid situation when one RX queue can starve other queues,
+each RX queue uses its own mempool.
+
+.. code-block:: c
+
+ nb_mbuf = RTE_MAX(max_flow_num, 2UL * MAX_PKT_BURST) * RTE_LIBRTE_IP_FRAG_MAX_FRAGS;
+ nb_mbuf *= (port_conf.rxmode.max_rx_pkt_len + BUF_SIZE - 1) / BUF_SIZE;
+ nb_mbuf *= 2; /* ipv4 and ipv6 */
+ nb_mbuf += RTE_TEST_RX_DESC_DEFAULT + RTE_TEST_TX_DESC_DEFAULT;
+ nb_mbuf = RTE_MAX(nb_mbuf, (uint32_t)NB_MBUF);
+
+ snprintf(buf, sizeof(buf), "mbuf_pool_%u_%u", lcore, queue);
+
+ if ((rxq->pool = rte_mempool_create(buf, nb_mbuf, MBUF_SIZE, 0, sizeof(struct rte_pktmbuf_pool_private), rte_pktmbuf_pool_init, NULL,
+ rte_pktmbuf_init, NULL, socket, MEMPOOL_F_SP_PUT | MEMPOOL_F_SC_GET)) == NULL) {
+
+ RTE_LOG(ERR, IP_RSMBL, "mempool_create(%s) failed", buf);
+ return -1;
+ }
+
+Packet Reassembly and Forwarding
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+For each input packet, the packet forwarding operation is done by the l3fwd_simple_forward() function.
+If the packet is an IPv4 or IPv6 fragment, then it calls rte_ipv4_reassemble_packet() for IPv4 packets,
+or rte_ipv6_reassemble_packet() for IPv6 packets.
+These functions either return a pointer to valid mbuf that contains reassembled packet,
+or NULL (if the packet can't be reassembled for some reason).
+Then l3fwd_simple_forward() continues with the code for the packet forwarding decision
+(that is, the identification of the output interface for the packet) and
+actual transmit of the packet.
+
+The rte_ipv4_reassemble_packet() or rte_ipv6_reassemble_packet() are responsible for:
+
+#. Searching the Fragment Table for entry with packet's <IP Source Address, IP Destination Address, Packet ID>
+
+#. If the entry is found, then check if that entry already timed-out.
+ If yes, then free all previously received fragments,
+ and remove information about them from the entry.
+
+#. If no entry with such key is found, then try to create a new one by one of two ways:
+
+ #. Use as empty entry
+
+ #. Delete a timed-out entry, free mbufs associated with it mbufs and store a new entry with specified key in it.
+
+#. Update the entry with new fragment information and check
+ if a packet can be reassembled (the packet's entry contains all fragments).
+
+ #. If yes, then, reassemble the packet, mark table's entry as empty and return the reassembled mbuf to the caller.
+
+ #. If no, then just return a NULL to the caller.
+
+If at any stage of packet processing a reassembly function encounters an error
+(can't insert new entry into the Fragment table, or invalid/timed-out fragment),
+then it will free all associated with the packet fragments,
+mark the table entry as invalid and return NULL to the caller.
+
+Debug logging and Statistics Collection
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The RTE_LIBRTE_IP_FRAG_TBL_STAT controls statistics collection for the IP Fragment Table.
+This macro is disabled by default.
+To make ip_reassembly print the statistics to the standard output,
+the user must send either an USR1, INT or TERM signal to the process.
+For all of these signals, the ip_reassembly process prints Fragment table statistics for each RX queue,
+plus the INT and TERM will cause process termination as usual.
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