--------
The application demonstrates the use of zero-copy buffers for packet forwarding.
-The initialization and run-time paths are very similar to those of the L2 forwarding application
-(see Chapter 9 "L2 Forwarding Sample Application (in Real and Virtualized Environments)" for details more information).
+The initialization and run-time paths are very similar to those of the :doc:`l2_forward_real_virtual`.
This guide highlights the differences between the two applications.
There are two key differences from the L2 Forwarding sample application:
The lookup table is composed of pairs of destination IPv4 address (the FBK)
and a port mask associated with that IPv4 address.
+.. note::
+
+ The max port mask supported in the given hash table is 0xf, so only first
+ four ports can be supported.
+ If using non-consecutive ports, use the destination IPv4 address accordingly.
+
For convenience and simplicity, this sample application does not take IANA-assigned multicast addresses into account,
but instead equates the last four bytes of the multicast group (that is, the last four bytes of the destination IP address)
with the mask of ports to multicast packets to.
Also, the application does not consider the Ethernet addresses;
it looks only at the IPv4 destination address for any given packet.
-Building 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/ipv4_multicast
-
-#. Set the target (a default target is used if not specified). For example:
+Compiling the Application
+-------------------------
- .. code-block:: console
+To compile the sample application see :doc:`compiling`.
- 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
-
-.. note::
-
- The compiled application is written to the build subdirectory.
- To have the application written to a different location,
- the O=/path/to/build/directory option may be specified in the make command.
+The application is located in the ``ipv4_multicast`` sub-directory.
Running the Application
-----------------------
.. code-block:: console
- ./build/ipv4_multicast -c 0x00f -n 3 -- -p 0x3 -q 1
+ ./build/ipv4_multicast -l 0-3 -n 3 -- -p 0x3 -q 1
In this command:
-* The -c option enables cores 0, 1, 2 and 3
+* The -l option enables cores 0, 1, 2 and 3
* The -n option specifies 3 memory channels
The following sections provide some explanation of the code.
As mentioned in the overview section,
-the initialization and run-time paths are very similar to those of the L2 Forwarding sample application
-(see Chapter 9 "L2 Forwarding Sample Application in Real and Virtualized Environments" for more information).
+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 IPv4 Multicast sample application.
Memory Pool Initialization
.. code-block:: c
- packet_pool = rte_mempool_create("packet_pool", NB_PKT_MBUF, PKT_MBUF_SIZE, 32, sizeof(struct rte_pktmbuf_pool_private),
- rte_pktmbuf_pool_init, NULL, rte_pktmbuf_init, NULL, rte_socket_id(), 0);
-
- header_pool = rte_mempool_create("header_pool", NB_HDR_MBUF, HDR_MBUF_SIZE, 32, 0, NULL, NULL, rte_pktmbuf_init, NULL, rte_socket_id(), 0);
- clone_pool = rte_mempool_create("clone_pool", NB_CLONE_MBUF,
- CLONE_MBUF_SIZE, 32, 0, NULL, NULL, rte_pktmbuf_init, NULL, rte_socket_id(), 0);
+ packet_pool = rte_pktmbuf_pool_create("packet_pool", NB_PKT_MBUF, 32,
+ 0, PKT_MBUF_DATA_SIZE, rte_socket_id());
+ header_pool = rte_pktmbuf_pool_create("header_pool", NB_HDR_MBUF, 32,
+ 0, HDR_MBUF_DATA_SIZE, rte_socket_id());
+ clone_pool = rte_pktmbuf_pool_create("clone_pool", NB_CLONE_MBUF, 32,
+ 0, 0, rte_socket_id());
The reason for this is because indirect buffers are not supposed to hold any packet data and
therefore can be initialized with lower amount of reserved memory for each buffer.
/* Remove the Ethernet header from the input packet */
iphdr = (struct ipv4_hdr *)rte_pktmbuf_adj(m, sizeof(struct ether_hdr));
- RTE_MBUF_ASSERT(iphdr != NULL);
+ RTE_ASSERT(iphdr != NULL);
dest_addr = rte_be_to_cpu_32(iphdr->dst_addr);
Then, the packet is checked to see if it has a multicast destination address and
for (n = 0; v != 0; v &= v - 1, n++)
;
- return (n);
+ return n;
}
This is done to determine which forwarding algorithm to use.
.. code-block:: c
- /* construct destination ethernet address */
+ /* construct destination Ethernet address */
dst_eth_addr = ETHER_ADDR_FOR_IPV4_MCAST(dest_addr);
Since Ethernet addresses are also part of the multicast process, each outgoing packet carries the same destination Ethernet address.
-The destination Ethernet address is constructed from the lower 23 bits of the multicast group ORed
+The destination Ethernet address is constructed from the lower 23 bits of the multicast group OR-ed
with the Ethernet address 01:00:5e:00:00:00, as per RFC 1112:
.. code-block:: c
.. code-block:: c
- static inline void mcast_send_pkt(struct rte_mbuf *pkt, struct ether_addr *dest_addr, struct lcore_queue_conf *qconf, uint8_t port)
+ static inline void mcast_send_pkt(struct rte_mbuf *pkt, struct ether_addr *dest_addr, struct lcore_queue_conf *qconf, uint16_t port)
{
struct ether_hdr *ethdr;
uint16_t len;
ethdr = (struct ether_hdr *)rte_pktmbuf_prepend(pkt, (uint16_t) sizeof(*ethdr));
- RTE_MBUF_ASSERT(ethdr != NULL);
+ RTE_ASSERT(ethdr != NULL);
ether_addr_copy(dest_addr, ðdr->d_addr);
ether_addr_copy(&ports_eth_addr[port], ðdr->s_addr);
/* Create new mbuf for the header. */
if (unlikely ((hdr = rte_pktmbuf_alloc(header_pool)) == NULL))
- return (NULL);
+ return NULL;
/* If requested, then make a new clone packet. */
if (use_clone != 0 && unlikely ((pkt = rte_pktmbuf_clone(pkt, clone_pool)) == NULL)) {
rte_pktmbuf_free(hdr);
- return (NULL);
+ return NULL;
}
/* prepend new header */
/* update header's fields */
hdr->pkt.pkt_len = (uint16_t)(hdr->pkt.data_len + pkt->pkt.pkt_len);
- hdr->pkt.nb_segs = (uint8_t)(pkt->pkt.nb_segs + 1);
+ hdr->pkt.nb_segs = pkt->pkt.nb_segs + 1;
/* copy metadata from source packet */
hdr->ol_flags = pkt->ol_flags;
rte_mbuf_sanity_check(hdr, RTE_MBUF_PKT, 1);
- return (hdr);
+ return hdr;
}
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