09/02/2024 15:58, Ferruh Yigit: > On 2/9/2024 1:44 PM, Thomas Monjalon wrote: > > 09/02/2024 13:11, Ferruh Yigit: > >> On 2/9/2024 10:12 AM, Thomas Monjalon wrote: > >>> 09/02/2024 00:54, Ferruh Yigit: > >>>> On 1/30/2024 11:25 AM, Gavin Li wrote: > >>>>> Currently, DPDK supports VXLAN and VXLAN-GPE with similar header > >>>>> structures and we are working on adding support for VXLAN-GBP which is > >>>>> another extension to VXLAN. More extension of VXLAN may be added in the > >>>>> future. > >>>>> > >>>>> VXLAN and VXLAN-GBP use the same UDP port(4789) while VXLAN-GPE uses a > >>>>> different one, 4790. The three protocols have the same header length and > >>>>> overall similar header structure as below. > >>>>> 0 1 2 3 > >>>>> 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 > >>>>> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ > >>>>> |R|R|R|R|I|R|R|R| Reserved | > >>>>> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ > >>>>> | VXLAN Network Identifier (VNI) | Reserved | > >>>>> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ > >>>>> > >>>>> Figure 1: VXLAN Header > >>>>> > >>>>> 0 1 2 3 > >>>>> 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 > >>>>> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ > >>>>> |R|R|Ver|I|P|B|O| Reserved |Next Protocol | > >>>>> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ > >>>>> | VXLAN Network Identifier (VNI) | Reserved | > >>>>> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ > >>>>> > >>>>> Figure 2: VXLAN-GPE Header > >>>>> > >>>>> 0 1 2 3 > >>>>> 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 > >>>>> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ > >>>>> |G|R|R|R|I|R|R|R|R|D|R|R|A|R|R|R| Group Policy ID | > >>>>> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ > >>>>> | VXLAN Network Identifier (VNI) | Reserved | > >>>>> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ > >>>>> > >>>>> Figure 3: VXLAN-GBP Extension > >>>>> > >>>>> Both VXLAN-GPE and VXLAN-GBP extended VXLAN by redefining its reserved > >>>>> bits, which means the packets can be processed with same pattern and > >>>>> most > >>>>> of the code can be reused. Instead of adding more new items by > >>>>> copying/pasting code for the VXLAN extensions in the future, it’s better > >>>>> to use existing VXLAN infrastructure and add support code in it. > >>>>> > >>>> > >>>> Hi Gavin, > >>>> > >>>> The motivation is to prevent code duplication, and the code mentioned is > >>>> the driver code, right? > >>> > >>> The motivation is mainly to provide a unified and more explicit API. > >>> > >> > >> From user perspective, I think existing approach is more explicit, > >> because it sets VXLAN or VXLAN_GPE flow types. > >> > >> I am trying to understand the benefit, how unifying flow type in the API > >> helps to the user? > >> > >>>> Overall OK to unify "struct rte_vxlan_hdr" although it makes the struct > >>>> a little complex, perhaps we can consider extraction some nested structs > >>>> as named struct, no strong opinion. > >>>> > >>>> > >>>> But not sure about removing the flow item types for VXLAN-GPE, or not > >>>> adding for VXLAN-GBP. > >>>> > >>>> Think about a case user adding a rule, which has a item type as VXLAN > >>>> and in the protocol header some bits are set, lets say first word, last > >>>> byte is set, how driver will know if to take it as GPE "next protocol" > >>>> or "group policy id". > >>> > >>> The driver may decide depending on the UDP port and some distinguishing > >>> flags. > >>> If you want to match on GBP, you should includes the GBP flag in your > >>> pattern, > >>> no need to use a separate item. > >>> > >> > >> Why not be more explicit? > >> It helps to driver to know more about the pattern to be able to create > >> proper flow rule, if there is an obvious way for driver to differentiate > >> these protocol extensions, and flow item type is redundant, I can > >> understand the proposal, but otherwise I think better to keep flow items > >> for extensions. > > > > In any case we need the simple VXLAN item. > > If we have GPE and GBP specialized items, > > what means a match on the simple VXLAN? > > Does it include packets with other extensions or exclude them? > > Matching the bits in the protocol make such decision explicit. > > > >> When a rule is set in HW, HW may not care about the protocol, as long as > >> bits in the rule match with the packet, HW can apply the action. > >> But for driver to be able to set the rule properly, it needs more > >> explicit information. > > > > Yes information is in the pattern to match. > > > >> Lets assume driver API get a pattern with 'RTE_FLOW_ITEM_TYPE_VXLAN' > >> type and "struct rte_flow_item_vxlan", at this point driver doesn't know > >> if it is VXLAN or any of the extensions. > > > > Yes it knows because of the matched bits in the pattern. > > If the rule specify a match on GBP flag = 1, it is GBP only. > > If the rule specify a match on GBP flag = 0, it excludes GBP. > > If the rule does not mask GBP flag, it includes GBP. > > > > > OK, VXLAN-GBP protocol has a GBP flag that gives a way to differentiate > the extension, so flow item for it becomes redundant and we can get rid > of it.
Yes I think so. > Is it same for the other extensions? > If we use VXLAN flow item and by setting specific field in pattern can > we differentiate VXLAN and any other extension? > Or in some cases other information, like UDP port, needs to be taken > into account to differentiate protocol/extension? For VXLAN-GPE, differentiation is on UDP port. Remember we have an API to fill some UDP ports: rte_eth_dev_udp_tunnel_port_add with RTE_ETH_TUNNEL_TYPE_VXLAN_GPE The UDP port value/mask may be part of the flow rule pattern. > I found a spec for VXLAN-GBP, but it shows as sub-header for VXLAN-GPE, > different than what this RFC describes: > https://datatracker.ietf.org/doc/html/draft-lemon-vxlan-gpe-gbp > > Can you please share link for VXLAN-GBP Extension spec? I will let Gavin explain here, I'm not an expert.
