7dbd7a6413
2 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Jiayu Hu
|
0d2cbe59b7 |
lib/gro: support TCP/IPv4
In this patch, we introduce five APIs to support TCP/IPv4 GRO.
- gro_tcp4_reassemble: reassemble an inputted TCP/IPv4 packet.
- gro_tcp4_tbl_create: create a TCP/IPv4 reassembly table, which is used
to merge packets.
- gro_tcp4_tbl_destroy: free memory space of a TCP/IPv4 reassembly table.
- gro_tcp4_tbl_pkt_count: return the number of packets in a TCP/IPv4
reassembly table.
- gro_tcp4_tbl_timeout_flush: flush timeout packets from a TCP/IPv4
reassembly table.
TCP/IPv4 GRO API assumes all inputted packets are with correct IPv4
and TCP checksums. And TCP/IPv4 GRO API doesn't update IPv4 and TCP
checksums for merged packets. If inputted packets are IP fragmented,
TCP/IPv4 GRO API assumes they are complete packets (i.e. with L4
headers).
In TCP/IPv4 GRO, we use a table structure, called TCP/IPv4 reassembly
table, to reassemble packets. A TCP/IPv4 reassembly table includes a key
array and a item array, where the key array keeps the criteria to merge
packets and the item array keeps packet information.
One key in the key array points to an item group, which consists of
packets which have the same criteria value. If two packets are able to
merge, they must be in the same item group. Each key in the key array
includes two parts:
- criteria: the criteria of merging packets. If two packets can be
merged, they must have the same criteria value.
- start_index: the index of the first incoming packet of the item group.
Each element in the item array keeps the information of one packet. It
mainly includes three parts:
- firstseg: the address of the first segment of the packet
- lastseg: the address of the last segment of the packet
- next_pkt_index: the index of the next packet in the same item group.
All packets in the same item group are chained by next_pkt_index.
With next_pkt_index, we can locate all packets in the same item
group one by one.
To process an incoming packet needs three steps:
a. check if the packet should be processed. Packets with one of the
following properties won't be processed:
- FIN, SYN, RST, URG, PSH, ECE or CWR bit is set;
- packet payload length is 0.
b. traverse the key array to find a key which has the same criteria
value with the incoming packet. If find, goto step c. Otherwise,
insert a new key and insert the packet into the item array.
c. locate the first packet in the item group via the start_index in the
key. Then traverse all packets in the item group via next_pkt_index.
If find one packet which can merge with the incoming one, merge them
together. If can't find, insert the packet into this item group.
Signed-off-by: Jiayu Hu <jiayu.hu@intel.com>
Reviewed-by: Jianfeng Tan <jianfeng.tan@intel.com>
|
||
|
Jiayu Hu
|
e996506a1c |
lib/gro: add Generic Receive Offload API framework
Generic Receive Offload (GRO) is a widely used SW-based offloading technique to reduce per-packet processing overhead. It gains performance by reassembling small packets into large ones. This patchset is to support GRO in DPDK. To support GRO, this patch implements a GRO API framework. To enable more flexibility to applications, DPDK GRO is implemented as a user library. Applications explicitly use the GRO library to merge small packets into large ones. DPDK GRO provides two reassembly modes. One is called lightweight mode, the other is called heavyweight mode. If applications want to merge packets in a simple way and the number of packets is relatively small, they can use the lightweight mode. If applications need more fine-grained controls, they can choose the heavyweight mode. rte_gro_reassemble_burst is the main reassembly API which is used in lightweight mode and processes N packets at a time. For applications, performing GRO in lightweight mode is simple. They just need to invoke rte_gro_reassemble_burst. Applications can get GROed packets as soon as rte_gro_reassemble_burst returns. rte_gro_reassemble is the main reassembly API which is used in heavyweight mode and tries to merge N inputted packets with the packets in GRO reassembly tables. For applications, performing GRO in heavyweight mode is relatively complicated. Before performing GRO, applications need to create a GRO context object, which keeps reassembly tables of desired GRO types, by rte_gro_ctx_create. Then applications can use rte_gro_reassemble to merge packets. The GROed packets are in the reassembly tables of the GRO context object. If applications want to get them, applications need to manually flush them by flush API. Signed-off-by: Jiayu Hu <jiayu.hu@intel.com> Reviewed-by: Jianfeng Tan <jianfeng.tan@intel.com> |