[dpdk-dev] [PATCH v5 00/13] net/mlx5: e-switch VXLAN encap/decap hardware offload

[Shahaf Shuler]

Saturday, November 3, 2018 8:19 AM, Slava Ovsiienko:
> Subject: [PATCH v5 00/13] net/mlx5: e-switch VXLAN encap/decap hardware
> offload
> 
> This patchset adds the VXLAN encapsulation/decapsulation hardware offload
> feature for E-Switch.
> 
> A typical use case of tunneling infrastructure is port representors in
> switchdev mode, with VXLAN traffic encapsulation performed on traffic
> coming *from* a representor and decapsulation on traffic going *to* that
> representor, in order to transparently assign a given VXLAN to VF traffic.
> 
> Since these actions are supported at the E-Switch level, the "transfer"
> attribute must be set on such flow rules. They must also be combined with a
> port redirection action to make sense.
> 
> Since only ingress is supported, encapsulation flow rules are normally applied
> on a physical port and emit traffic to a port representor.
> The opposite order is used for decapsulation.
> 
> Like other mlx5 E-Switch flow rule actions, these ones are implemented
> through Linux's TC flower API. Since the Linux interface for VXLAN
> encap/decap involves virtual network devices (i.e. ip link add type
> 		vxlan [...]), the PMD dynamically spawns them on a needed
> basis through Netlink calls. These VXLAN implicitly created devices are called
> VTEPs (Virtual Tunnel End Points).
> 
> VXLAN interfaces are dynamically created for each local port of outer
> networks and then used as targets for TC "flower" filters in order to perform
> encapsulation. For decapsulation the VXLAN devices are created for each
> unique UDP-port. These VXLAN interfaces are system-wide, the only one
> device with given UDP port can exist in the system (the attempt of creating
> another device with the same UDP local port returns EEXIST), so PMD should
> support the shared (between PMD instances) device database.
> 
> Rules samples consideraions:
> 
> $PF 		- physical device, outer network
> $VF 		- representor for VF, outer/inner network
> $VXLAN		- VTEP netdev name
> $PF_OUTER_IP 	- $PF IP (v4 or v6) within outer network
> $REMOTE_IP 	- remote peer IP (v4 or v6) within outer network
> $LOCAL_PORT	- local UDP port
> $REMOTE_PORT	- remote UDP port
> 
> VXLAN VTEP creation with iproute2 (PMD does the same via Netlink):
> 
> - for encapsulation:
> 
>   ip link add $VXLAN type vxlan dstport $LOCAL_PORT external dev $PF
>   ip link set dev $VXLAN up
>   tc qdisc del dev $VXLAN ingress
>   tc qdisc add dev $VXLAN ingress
> 
> $LOCAL_PORT for egress encapsulated traffic (note, this is not source UDP
> port in the VXLAN header, it is just UDP port assigned
> to VTEP, no practical usage) is selected from available	UDP ports
> automatically in range 30000-60000.
> 
> - for decapsulation:
> 
>   ip link add $VXLAN type vxlan dstport $LOCAL_PORT external
>   ip link set dev $VXLAN up
>   tc qdisc del dev $VXLAN ingress
>   tc qdisc add dev $VXLAN ingress
> 
> $LOCAL_PORT is UDP port receiving the VXLAN traffic from outer networks.
> 
> All ingress UDP traffic with given UDP destination port from ALL existing
> netdevs is routed by kernel to the $VXLAN net device. While applying the
> rule the kernel checks the IP parameter withing rule, determines the
> appropriate underlaying PF and tryes to setup the rule hardware offload.
> 
> VXLAN encapsulation
> 
> VXLAN encap rules are applied to the VF ingress traffic and have the VTEP as
> actual redirection destinations instead of outer PF.
> The encapsulation rule should provide:
> - redirection action VF->PF
> - VF port ID
> - some inner network parameters (MACs)
> - the tunnel outer source IP (v4/v6), (IS A MUST)
> - the tunnel outer destination IP (v4/v6), (IS A MUST).
> - VNI - Virtual Network Identifier (IS A MUST)
> 
> VXLAN encapsulation rule sample for tc utility:
> 
>   tc filter add dev $VF protocol all parent ffff: flower skip_sw \
> 	action tunnel_key set dst_port $REMOTE_PORT \
> 	src_ip $PF_OUTER_IP dst_ip $REMOTE_IP id $VNI \
> 	action mirred egress redirect dev $VXLAN
> 
> VXLAN encapsulation rule sample for testpmd:
> 
> - Setting up outer properties of VXLAN tunnel:
> 
>   set vxlan ip-version ipv4 vni $VNI \
> 	udp-src $IGNORED udp-dst $REMOTE_PORT \
> 	ip-src $PF_OUTER_IP ip-dst $REMOTE_IP \
>  	eth-src $IGNORED eth-dst $REMOTE_MAC
> 
> - Creating a flow rule on port ID 4 performing VXLAN encapsulation
>   with the abovementioned properties and directing the resulting
>   traffic to port ID 0:
> 
>   flow create 4 ingress transfer pattern eth src is $INNER_MAC / end
> 	actions vxlan_encap / port_id id 0 / end
> 
> There is no direct way found to provide kernel with all required
> encapsulatioh header parameters. The encapsulation VTEP is created
> attached to the outer interface and assumed as default path for egress
> encapsulated traffic. The outer tunnel IP address are assigned to interface
> using Netlink, the implicit route is created like this:
> 
>   ip addr add <src_ip> peer <dst_ip> dev <outer> scope link
> 
> The peer address option provides implicit route, and scope link attribute
> reduces the risk of conflicts. At initialization time all local scope link addresses
> are flushed from the outer network device.
> 
> The destination MAC address is provided via permenent neigh rule:
> 
>  ip neigh add dev <outer> lladdr <dst_mac> to <dst_ip> nud permanent
> 
> At initialization time all neigh rules of permanent type are flushed from the
> outer network device.
> 
> VXLAN decapsulation
> 
> VXLAN decap rules are applied to the ingress traffic of VTEP ($VXLAN) device
> instead of PF. The decapsulation rule should provide:
> - redirection action PF->VF
> - VF port ID as redirection destination
> - $VXLAN device as ingress traffic source
> - the tunnel outer source IP (v4/v6), (optional)
> - the tunnel outer destination IP (v4/v6), (IS A MUST)
> - the tunnel local UDP port (IS A MUST, PMD looks for appropriate VTEP
>   with given local UDP port)
> - VNI - Virtual Network Identifier (IS A MUST)
> 
> VXLAN decap rule sample for tc utility:
> 
>   tc filter add dev $VXLAN protocol all parent ffff: flower skip_sw \
> 	enc_src_ip $REMOTE_IP enc_dst_ip $PF_OUTER_IP enc_key_id $VNI
> \
> 	nc_dst_port $LOCAL_PORT \
> 	action tunnel_key unset action mirred egress redirect dev $VF
> 
> VXLAN decap rule sample for testpmd:
> 
> - Creating a flow on port ID 0 performing VXLAN decapsulation and directing
>   the result to port ID 4 with checking inner properties:
> 
>   flow create 0 ingress transfer pattern /
>   	ipv4 src is $REMOTE_IP dst $PF_LOCAL_IP /
> 	udp src is 9999 dst is $LOCAL_PORT / vxlan vni is $VNI /
> 	eth src is 00:11:22:33:44:55 dst is $INNER_MAC / end
>         actions vxlan_decap / port_id id 4 / end
> 
> The VXLAN encap/decap rules constrains (implied by current kernel support)
> 
> - VXLAN decapsulation provided for PF->VF direction only
> - VXLAN encapsulation provided for VF->PF direction only
> - current implementation will support non-shared database of VTEPs
>   (impossible simultaneous usage of the same UDP port by several
>    instances of DPDK apps)
> 
> Suggested-by: Adrien Mazarguil <adrien.mazarguil at 6wind.com>
> Signed-off-by: Viacheslav Ovsiienko <viacheslavo at mellanox.com>
> 

Well done. 
Applied to next-net-mlx, thanks.