On TX side, it is also possible for an application to delegate some
processing to the hardware if it supports it. For instance, the
-PKT_TX_IP_CKSUM flag allows to offload the computation of the IPv4
+RTE_MBUF_F_TX_IP_CKSUM flag allows to offload the computation of the IPv4
checksum.
The following examples explain how to configure different TX offloads on
mb->l2_len = len(out_eth)
mb->l3_len = len(out_ip)
- mb->ol_flags |= PKT_TX_IPV4 | PKT_TX_IP_CSUM
+ mb->ol_flags |= RTE_MBUF_F_TX_IPV4 | RTE_MBUF_F_TX_IP_CSUM
set out_ip checksum to 0 in the packet
- This is supported on hardware advertising DEV_TX_OFFLOAD_IPV4_CKSUM.
+ This is supported on hardware advertising RTE_ETH_TX_OFFLOAD_IPV4_CKSUM.
- calculate checksum of out_ip and out_udp::
mb->l2_len = len(out_eth)
mb->l3_len = len(out_ip)
- mb->ol_flags |= PKT_TX_IPV4 | PKT_TX_IP_CSUM | PKT_TX_UDP_CKSUM
+ mb->ol_flags |= RTE_MBUF_F_TX_IPV4 | RTE_MBUF_F_TX_IP_CSUM | RTE_MBUF_F_TX_UDP_CKSUM
set out_ip checksum to 0 in the packet
set out_udp checksum to pseudo header using rte_ipv4_phdr_cksum()
- This is supported on hardware advertising DEV_TX_OFFLOAD_IPV4_CKSUM
- and DEV_TX_OFFLOAD_UDP_CKSUM.
+ This is supported on hardware advertising RTE_ETH_TX_OFFLOAD_IPV4_CKSUM
+ and RTE_ETH_TX_OFFLOAD_UDP_CKSUM.
- calculate checksum of in_ip::
mb->l2_len = len(out_eth + out_ip + out_udp + vxlan + in_eth)
mb->l3_len = len(in_ip)
- mb->ol_flags |= PKT_TX_IPV4 | PKT_TX_IP_CSUM
+ mb->ol_flags |= RTE_MBUF_F_TX_IPV4 | RTE_MBUF_F_TX_IP_CSUM
set in_ip checksum to 0 in the packet
This is similar to case 1), but l2_len is different. It is supported
- on hardware advertising DEV_TX_OFFLOAD_IPV4_CKSUM.
+ on hardware advertising RTE_ETH_TX_OFFLOAD_IPV4_CKSUM.
Note that it can only work if outer L4 checksum is 0.
- calculate checksum of in_ip and in_tcp::
mb->l2_len = len(out_eth + out_ip + out_udp + vxlan + in_eth)
mb->l3_len = len(in_ip)
- mb->ol_flags |= PKT_TX_IPV4 | PKT_TX_IP_CSUM | PKT_TX_TCP_CKSUM
+ mb->ol_flags |= RTE_MBUF_F_TX_IPV4 | RTE_MBUF_F_TX_IP_CSUM | RTE_MBUF_F_TX_TCP_CKSUM
set in_ip checksum to 0 in the packet
set in_tcp checksum to pseudo header using rte_ipv4_phdr_cksum()
This is similar to case 2), but l2_len is different. It is supported
- on hardware advertising DEV_TX_OFFLOAD_IPV4_CKSUM and
- DEV_TX_OFFLOAD_TCP_CKSUM.
+ on hardware advertising RTE_ETH_TX_OFFLOAD_IPV4_CKSUM and
+ RTE_ETH_TX_OFFLOAD_TCP_CKSUM.
Note that it can only work if outer L4 checksum is 0.
- segment inner TCP::
mb->l2_len = len(out_eth + out_ip + out_udp + vxlan + in_eth)
mb->l3_len = len(in_ip)
mb->l4_len = len(in_tcp)
- mb->ol_flags |= PKT_TX_IPV4 | PKT_TX_IP_CKSUM | PKT_TX_TCP_CKSUM |
- PKT_TX_TCP_SEG;
+ mb->ol_flags |= RTE_MBUF_F_TX_IPV4 | RTE_MBUF_F_TX_IP_CKSUM | RTE_MBUF_F_TX_TCP_CKSUM |
+ RTE_MBUF_F_TX_TCP_SEG;
set in_ip checksum to 0 in the packet
set in_tcp checksum to pseudo header without including the IP
payload length using rte_ipv4_phdr_cksum()
- This is supported on hardware advertising DEV_TX_OFFLOAD_TCP_TSO.
+ This is supported on hardware advertising RTE_ETH_TX_OFFLOAD_TCP_TSO.
Note that it can only work if outer L4 checksum is 0.
- calculate checksum of out_ip, in_ip, in_tcp::
mb->outer_l3_len = len(out_ip)
mb->l2_len = len(out_udp + vxlan + in_eth)
mb->l3_len = len(in_ip)
- mb->ol_flags |= PKT_TX_OUTER_IPV4 | PKT_TX_OUTER_IP_CKSUM | \
- PKT_TX_IP_CKSUM | PKT_TX_TCP_CKSUM;
+ mb->ol_flags |= RTE_MBUF_F_TX_OUTER_IPV4 | RTE_MBUF_F_TX_OUTER_IP_CKSUM | \
+ RTE_MBUF_F_TX_IP_CKSUM | RTE_MBUF_F_TX_TCP_CKSUM;
set out_ip checksum to 0 in the packet
set in_ip checksum to 0 in the packet
set in_tcp checksum to pseudo header using rte_ipv4_phdr_cksum()
- This is supported on hardware advertising DEV_TX_OFFLOAD_IPV4_CKSUM,
- DEV_TX_OFFLOAD_UDP_CKSUM and DEV_TX_OFFLOAD_OUTER_IPV4_CKSUM.
+ This is supported on hardware advertising RTE_ETH_TX_OFFLOAD_IPV4_CKSUM,
+ RTE_ETH_TX_OFFLOAD_UDP_CKSUM and RTE_ETH_TX_OFFLOAD_OUTER_IPV4_CKSUM.
The list of flags and their precise meaning is described in the mbuf API
documentation (rte_mbuf.h). Also refer to the testpmd source code
(specifically the csumonly.c file) for details.
+Dynamic fields and flags
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+The size of the mbuf is constrained and limited;
+while the amount of metadata to save for each packet is quite unlimited.
+The most basic networking information already find their place
+in the existing mbuf fields and flags.
+
+If new features need to be added, the new fields and flags should fit
+in the "dynamic space", by registering some room in the mbuf structure:
+
+dynamic field
+ named area in the mbuf structure,
+ with a given size (at least 1 byte) and alignment constraint.
+
+dynamic flag
+ named bit in the mbuf structure,
+ stored in the field ``ol_flags``.
+
+The dynamic fields and flags are managed with the functions ``rte_mbuf_dyn*``.
+
+It is not possible to unregister fields or flags.
+
.. _direct_indirect_buffer:
Direct and Indirect Buffers
Debug
-----
-In debug mode (CONFIG_RTE_MBUF_DEBUG is enabled),
-the functions of the mbuf library perform sanity checks before any operation (such as, buffer corruption, bad type, and so on).
+In debug mode, the functions of the mbuf library perform sanity checks before any operation (such as, buffer corruption,
+bad type, and so on).
Use Cases
---------
git.droids-corp.org / dpdk.git / blobdiff