On Wed, Apr 18, 2012 at 9:50 PM, Simon Horman <ho...@verge.net.au> wrote: > This is a not yet well exercised implementation of STT intended for review, > I am sure there are numerous areas that need improvement. > > In particular: > - The transmit path's generation of partial checksums needs to be tested > - The VLAN stripping code needs to be excercised > - The code needs to be exercised in the presence of HW checksumming > - In general, the code has been exercised by running Open vSwtich in > KVM guests on the same host. Testing between physucal hosts is needed. > > This implementation is based on the CAPWAP implementation and in particular > includes defragmentation code almost identical to CAPWAP. It seems to me > that while fragmentation can be handled by GSO/TSO, defragmentation code is > needed in STT in the case where LRO/GRO doesn't reassemble an entire STT > frame for some reason. > > If the defragmentation code, which is of non-trivial length, remains more > or less in its present state then there is some scope for consolidation > with CAPWAP. Other code that may possibly be consolidated with CAPWAP has > been marked accordingly. > > This code depends on a encap_rcv hook being added to the Linux Kernel's TCP > stack. A patch to add such a hook will be posted separately. Ultimately > this change or some alternative will need to be applied to the mainline > Linux kernel's TCP stack if STT is to be widely deployed. Motivating this > change to the TCP stack is part of the purpose of this prototype STT > implementation. > > The configuration of STT is analogous to that of other tunneling > protocols such as GRE which are supported by Open vSwtich. > > e.g. > > ovs-vsctl add bridge project0 ports @newport \ > -- --id=@newport create port name=stt0 interfaces=[@newinterface] \ > -- --id=@newinterface create interface name=stt0 type=stt > options="remote_ip=10.0.99.192,key=64" > > Signed-off-by: Simon Horman <ho...@verge.net.au> > > --- > > v3 > * Correct stripping of vlan tag on transmit > * Correct setting of vlan TCI on recieve > - Use __vlan_hwaccel_put_tag instead of vlan_put_tag > * Use encap_rcv_enable() to enable receiving packets from the TCP stack > - This is an update for the new implementation of the TCP stack > patch that adds encap_rcv > * call pskb_may_pull() for STT_FRAME_HLEN + ETH_HLEN bytes in > process_stt_proto() as this is required by ovs_flow_extract() > * Include "stt: " in pr_fmt > * Make use of pr_* instead of printk > * Rate limit all packet-generated pr_* messages > * STT flags are 8bits wide so don't define them using __cpu_to_be16() > * Only include l4_offset if > 1. get_ip_summed(skb) is OVS_CSUM_PARTIAL > 2. skb->csum_start is non-zero > 3. it is between 0 and 255 > - Warn if the first two conditions are met but not the third one. > * Only set STT_FLAG_CHECKSUM_VERIFIED if > get_ip_summed(skb) is * OVS_CSUM_UNNECESSARY > * Print a debug message if get_ip_summed(skb) is OVS_CSUM_UNNECESSARY, > this case is yet to be exercised > * In the rx path, adjust skb->csum_start to take into account pulling > STT_FRAME_HLEN if get_ip_summed(skb) is OVS_CSUM_PARTIAL
Hi Simon, It looks like most of things that I mentioned in comments on the previous version are still present here. Is this just an intermediate version? > * Warn if skb->dev is NULL on defragmentation and stop processing the skb. > - This fixes a crash bug > - But how can this occur? The encap_rcv hook that you added to the TCP stack comes after the skb->dev = NULL line. This is why I wanted to push it is as close as possible to the socket lookup. _______________________________________________ dev mailing list dev@openvswitch.org http://openvswitch.org/mailman/listinfo/dev
