The csum forward engine was becoming too complex to be used and
extended (the next commits want to add the support of TSO):
- no explaination about what the code does
- code is not factorized, lots of code duplicated, especially between
ipv4/ipv6
- user command line api: use of bitmasks that need to be calculated by
the user
- the user flags don't have the same semantic:
- for legacy IP/UDP/TCP/SCTP, it selects software or hardware checksum
- for other (vxlan), it selects between hardware checksum or no
checksum
- the code relies too much on flags set by the driver without software
alternative (ex: PKT_RX_TUNNEL_IPV4_HDR). It is nice to be able to
compare a software implementation with the hardware offload.
This commit tries to fix these issues, and provide a simple definition
of what is done by the forward engine:
* Receive a burst of packets, and for supported packet types:
* - modify the IPs
* - reprocess the checksum in SW or HW, depending on testpmd command line
* configuration
* Then packets are transmitted on the output port.
*
* Supported packets are:
* Ether / (vlan) / IP|IP6 / UDP|TCP|SCTP .
* Ether / (vlan) / IP|IP6 / UDP / VxLAN / Ether / IP|IP6 / UDP|TCP|SCTP
*
* The network parser supposes that the packet is contiguous, which may
* not be the case in real life.
Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
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