[dpdk] 熟悉SDK与初步使用 （四）(L3 Forwarding源码分析)

接续前节：[dpdk] 熟悉SDK与初步使用 （三）(IP Fragmentation源码分析)

前文中的最后一个问题，搁置，并没有找到答案。所以继续阅读其他例子的代码，想必定能在其他位置看到答案。

使用，大致过了一般文档和代码，试运行一下：

绑定2,3,6,7四颗CPU核心。使用port1，port2.

port0/queue0/core2映射在一起。port0/queue1/core3映射在一起。port1/queue0/core6映射在一起。port1/queue1/core7映射在一起。

与前边的例子相同，依然要在代码级关掉 hw_ip_checksum。

[root@dpdk build]# ./l3fwd -l2,,, -- -p  --config "(0,0,2),(0,1,3),(1,0,6),(1,1,7)"
EAL: Detected  lcore(s)
EAL: Probing VFIO support...
EAL: WARNING: cpu flags constant_tsc=yes nonstop_tsc=no -> using unreliable clock cycles !
PMD: bnxt_rte_pmd_init() called for (null)
EAL: PCI device ::03.0 on NUMA socket -
EAL:   probe driver: 1af4: rte_virtio_pmd
EAL: PCI device ::04.0 on NUMA socket -
EAL:   probe driver: 1af4: rte_virtio_pmd
EAL: PCI device ::05.0 on NUMA socket -
EAL:   probe driver: 1af4: rte_virtio_pmd
EAL: PCI device ::06.0 on NUMA socket -
EAL:   probe driver: 1af4: rte_virtio_pmd
L3FWD: LPM or EM none selected, default LPM on
Initializing port  ... Creating queues: nb_rxq= nb_txq=...  Address::::::, Destination::::::, Allocated mbuf pool on socket
LPM: Adding route 0x01010100 /  ()
LPM: Adding route 0x02010100 /  ()
LPM: Adding route IPV6 /  ()
LPM: Adding route IPV6 /  ()
Allocated mbuf pool on socket
LPM: Adding route 0x01010100 /  ()
LPM: Adding route 0x02010100 /  ()
LPM: Adding route IPV6 /  ()
LPM: Adding route IPV6 /  ()
txq=,, txq=,, txq=,, txq=,,
Initializing port  ... Creating queues: nb_rxq= nb_txq=...  Address::::::, Destination::::::, txq=,, txq=,, txq=,, txq=,, 

Skipping disabled port 

Initializing rx queues on lcore  ... rxq=,,
Initializing rx queues on lcore  ... rxq=,,
Initializing rx queues on lcore  ... rxq=,,
Initializing rx queues on lcore  ... rxq=,, 

port  cannot parse packet type, please add --parse-ptype
EAL: Error - exiting with code:
  Cause: ptype check fails
[root@dpdk build]# 

以上出现的ERROR，刚好回答了（三）最后留下的疑问。此程序依然依赖硬件来完成packet type的识别。该参数“--parse-ptype”应该是启用了软件识别类型的功能，如下：

已经可以正常启动了。

[root@dpdk build]# ./l3fwd -l2,,, -- -p  --config "(0,0,2),(0,1,3),(1,0,6),(1,1,7)" --parse-ptype
EAL: Detected  lcore(s)
EAL: Probing VFIO support...
EAL: WARNING: cpu flags constant_tsc=yes nonstop_tsc=no -> using unreliable clock cycles !
PMD: bnxt_rte_pmd_init() called for (null)
EAL: PCI device ::03.0 on NUMA socket -
EAL:   probe driver: 1af4: rte_virtio_pmd
EAL: PCI device ::04.0 on NUMA socket -
EAL:   probe driver: 1af4: rte_virtio_pmd
EAL: PCI device ::05.0 on NUMA socket -
EAL:   probe driver: 1af4: rte_virtio_pmd
EAL: PCI device ::06.0 on NUMA socket -
EAL:   probe driver: 1af4: rte_virtio_pmd
soft parse-ptype is enabled
L3FWD: LPM or EM none selected, default LPM on
Initializing port  ... Creating queues: nb_rxq= nb_txq=...  Address::::::, Destination::::::, Allocated mbuf pool on socket
LPM: Adding route 0x01010100 /  ()
LPM: Adding route 0x02010100 /  ()
LPM: Adding route IPV6 /  ()
LPM: Adding route IPV6 /  ()
Allocated mbuf pool on socket
LPM: Adding route 0x01010100 /  ()
LPM: Adding route 0x02010100 /  ()
LPM: Adding route IPV6 /  ()
LPM: Adding route IPV6 /  ()
txq=,, txq=,, txq=,, txq=,,
Initializing port  ... Creating queues: nb_rxq= nb_txq=...  Address::::::, Destination::::::, txq=,, txq=,, txq=,, txq=,, 

Skipping disabled port 

Initializing rx queues on lcore  ... rxq=,,
Initializing rx queues on lcore  ... rxq=,,
Initializing rx queues on lcore  ... rxq=,,
Initializing rx queues on lcore  ... rxq=,, 

Port : softly parse packet type info
Port : softly parse packet type info
Port : softly parse packet type info
Port : softly parse packet type info

Checking link statusdone
Port  Link Up - speed  Mbps - full-duplex
Port  Link Up - speed  Mbps - full-duplex
L3FWD: entering main loop on lcore
L3FWD:  -- lcoreid= portid= rxqueueid=
L3FWD: entering main loop on lcore
L3FWD:  -- lcoreid= portid= rxqueueid=
L3FWD: entering main loop on lcore
L3FWD:  -- lcoreid= portid= rxqueueid=
L3FWD: entering main loop on lcore
L3FWD:  -- lcoreid= portid= rxqueueid=

接下来通过对代码的阅读调试，印证一下之前的想法。

先来一组测试包：

/home/tong/Data [tong@T7] [:]
> sudo tcpreplay-edit -D 0.0.0.0/:2.1.1.1/ -i tap-dpdk- -t -L  oicq-bak.pcap

基于代码里写死的路由规则，必要nat成2.1.1.1才能被转发。

发现了与参数 --parse-ptype 对应的函数：

rte_eth_add_rx_callback(portid, queueid, l3fwd_lkp.cb_parse_ptype, NULL)

此回调函数，设置了IP包的类型。

至此，解答了（三）中留下的问题。