On 5/16/23 07:33, Nobuhiro MIKI wrote:
> It supports flowlabel based load balancing by controlling the flowlabel
> of outer IPv6 header, which is already implemented in Linux kernel as
> seg6_flowlabel sysctl [1].
> 
> [1]: https://docs.kernel.org/networking/seg6-sysctl.html
> 
> Signed-off-by: Nobuhiro MIKI <[email protected]>
> ---
>  include/linux/openvswitch.h   |  3 +-
>  lib/netdev-native-tnl.c       | 23 ++++++++++-
>  lib/netdev-vport.c            |  8 ++++
>  lib/netdev.h                  | 12 ++++++
>  tests/tunnel-push-pop-ipv6.at | 72 +++++++++++++++++++++++++++++++++++
>  vswitchd/vswitch.xml          | 26 +++++++++++++
>  6 files changed, 141 insertions(+), 3 deletions(-)
> 
> diff --git a/include/linux/openvswitch.h b/include/linux/openvswitch.h
> index e305c331516b..278829cfa826 100644
> --- a/include/linux/openvswitch.h
> +++ b/include/linux/openvswitch.h
> @@ -855,7 +855,8 @@ struct ovs_action_push_tnl {
>       odp_port_t tnl_port;
>       odp_port_t out_port;
>       uint32_t header_len;
> -     uint32_t tnl_type;     /* For logging. */
> +     uint32_t tnl_type;       /* For logging. */
> +     uint32_t srv6_flowlabel; /* Only for SRv6. */
>       uint32_t header[TNL_PUSH_HEADER_SIZE / 4];
>  };
>  #endif
> diff --git a/lib/netdev-native-tnl.c b/lib/netdev-native-tnl.c
> index db1c4c6d9bfc..796169fe43ac 100644
> --- a/lib/netdev-native-tnl.c
> +++ b/lib/netdev-native-tnl.c
> @@ -910,6 +910,7 @@ netdev_srv6_build_header(const struct netdev *netdev,
>      }
>  
>      data->header_len += sizeof *srh + 8 * srh->rt_hdr.hdrlen;
> +    data->srv6_flowlabel = tnl_cfg->srv6_flowlabel;
>      data->tnl_type = OVS_VPORT_TYPE_SRV6;
>  out:
>      ovs_mutex_unlock(&dev->mutex);
> @@ -922,10 +923,28 @@ netdev_srv6_push_header(const struct netdev *netdev 
> OVS_UNUSED,
>                          struct dp_packet *packet,
>                          const struct ovs_action_push_tnl *data)
>  {
> +    struct ovs_16aligned_ip6_hdr *ip6 = dp_packet_l3(packet);
> +    ovs_be32 ipv6_label = 0;
>      int ip_tot_size;
> +    uint32_t flow;
>  
> -    netdev_tnl_push_ip_header(packet, data->header, data->header_len,
> -                              &ip_tot_size, 0);
> +    switch (data->srv6_flowlabel) {

I understand why you added a new filed into the ovs_action_push_tnl structure,
but I'm not sure we should do that.

If you'll look at the GRE seqno, for exmaple, you'll see that we're accessing
it via the original tnl_cfg structure stored in netdev.  The problem is that
it's not really thread safe, as I pointed out in review for the previous 
version.
I went ahead and tried to fix the thread-safety issues.  Patch set posted here:

  https://patchwork.ozlabs.org/project/openvswitch/list/?series=355820&state=*

After these changes you should be able to directly use tunnel config like this:

    switch (netdev_get_tunnel_config(netdev)->srv6_flowlabel) {

And it's going to be safe to do so.  And we'll not need to change the action
structure.

What do you think?


> +    case SRV6_FLOWLABEL_COPY:
> +        flow = ntohl(get_16aligned_be32(&ip6->ip6_flow));
> +        ipv6_label = (flow >> 28) == 6 ? htonl(flow & IPV6_LABEL_MASK) : 0;
> +        break;
> +
> +    case SRV6_FLOWLABEL_ZERO:
> +        ipv6_label = 0;
> +        break;
> +
> +    case SRV6_FLOWLABEL_COMPUTE:
> +        ipv6_label = htonl(dp_packet_get_rss_hash(packet) & IPV6_LABEL_MASK);
> +        break;
> +    }
> +
> +    netdev_tnl_push_ip_header(packet, data->header,
> +                              data->header_len, &ip_tot_size, ipv6_label);
>  }
>  
>  struct dp_packet *
> diff --git a/lib/netdev-vport.c b/lib/netdev-vport.c
> index 663ee8606c3b..2141621cf23e 100644
> --- a/lib/netdev-vport.c
> +++ b/lib/netdev-vport.c
> @@ -792,6 +792,14 @@ set_tunnel_config(struct netdev *dev_, const struct smap 
> *args, char **errp)
>                                name, node->value);
>                  break;
>              }
> +        } else if (!strcmp(node->key, "srv6_flowlabel")) {
> +            if (!strcmp(node->value, "zero")) {
> +                tnl_cfg.srv6_flowlabel = SRV6_FLOWLABEL_ZERO;
> +            } else if (!strcmp(node->value, "compute")) {
> +                tnl_cfg.srv6_flowlabel = SRV6_FLOWLABEL_COMPUTE;
> +            } else {
> +                tnl_cfg.srv6_flowlabel = SRV6_FLOWLABEL_COPY;
> +            }
>          } else if (!strcmp(node->key, "payload_type")) {
>              if (!strcmp(node->value, "mpls")) {
>                   tnl_cfg.payload_ethertype = htons(ETH_TYPE_MPLS);
> diff --git a/lib/netdev.h b/lib/netdev.h
> index ff207f56c28c..58a438c8347c 100644
> --- a/lib/netdev.h
> +++ b/lib/netdev.h
> @@ -97,6 +97,17 @@ enum netdev_pt_mode {
>      NETDEV_PT_LEGACY_L3,
>  };
>  
> +enum netdev_srv6_flowlabel {
> +    /* Copy the flowlabel from inner packet. */
> +    SRV6_FLOWLABEL_COPY,
> +
> +    /* Simply set flowlabel to 0. */
> +    SRV6_FLOWLABEL_ZERO,
> +
> +    /* Set RSS hash of inner pakcet to flowlabel. */

I'd avoid using 'RSS' in the documentation.  It's an implementation
detail that can be changed.  What's importan here is that it's a
hash over L3/L4 fields of the inner packet.

> +    SRV6_FLOWLABEL_COMPUTE,
> +};
> +
>  /* Configuration specific to tunnels. */
>  struct netdev_tunnel_config {
>      ovs_be64 in_key;
> @@ -144,6 +155,7 @@ struct netdev_tunnel_config {
>      uint8_t srv6_num_segs;
>      #define SRV6_MAX_SEGS 6
>      struct in6_addr srv6_segs[SRV6_MAX_SEGS];
> +    enum netdev_srv6_flowlabel srv6_flowlabel;
>  };
>  
>  void netdev_run(void);
> diff --git a/tests/tunnel-push-pop-ipv6.at b/tests/tunnel-push-pop-ipv6.at
> index e300fe3a0d26..35d56593d37d 100644
> --- a/tests/tunnel-push-pop-ipv6.at
> +++ b/tests/tunnel-push-pop-ipv6.at
> @@ -1,5 +1,77 @@
>  AT_BANNER([tunnel_push_pop_ipv6])
>  
> +AT_SETUP([tunnel_push_pop_ipv6 - srv6])
> +
> +OVS_VSWITCHD_START([add-port br0 p0 -- set Interface p0 type=dummy 
> ofport_request=1 other-config:hwaddr=aa:55:aa:55:00:00 options:pcap=p0.pcap])
> +AT_CHECK([ovs-vsctl add-br int-br1 -- set bridge int-br1 
> datapath_type=dummy], [0])
> +AT_CHECK([ovs-vsctl add-br int-br2 -- set bridge int-br2 
> datapath_type=dummy], [0])
> +AT_CHECK([ovs-vsctl add-br int-br3 -- set bridge int-br3 
> datapath_type=dummy], [0])
> +AT_CHECK([ovs-vsctl add-port int-br1 t1 -- set Interface t1 type=srv6 \
> +                       options:remote_ip=2001:cafe::91 ofport_request=2 \
> +                       options:srv6_flowlabel=copy \
> +                       ], [0])
> +AT_CHECK([ovs-vsctl add-port int-br2 t2 -- set Interface t2 type=srv6 \
> +                       options:remote_ip=2001:cafe::92 ofport_request=3 \
> +                       options:srv6_flowlabel=zero \
> +                       ], [0])
> +AT_CHECK([ovs-vsctl add-port int-br3 t3 -- set Interface t3 type=srv6 \
> +                       options:remote_ip=2001:cafe::93 ofport_request=4 \
> +                       options:srv6_flowlabel=compute \
> +                       ], [0])
> +
> +dnl First setup dummy interface IP address, then add the route
> +dnl so that tnl-port table can get valid IP address for the device.
> +AT_CHECK([ovs-appctl netdev-dummy/ip6addr br0 2001:cafe::88/24], [0], [OK
> +])
> +AT_CHECK([ovs-appctl ovs/route/add 2001:cafe::0/24 br0], [0], [OK
> +])
> +AT_CHECK([ovs-appctl tnl/neigh/set br0 2001:cafe::91 aa:55:aa:55:00:01], 
> [0], [OK
> +])
> +AT_CHECK([ovs-appctl tnl/neigh/set br0 2001:cafe::92 aa:55:aa:55:00:02], 
> [0], [OK
> +])
> +AT_CHECK([ovs-appctl tnl/neigh/set br0 2001:cafe::93 aa:55:aa:55:00:03], 
> [0], [OK
> +])
> +AT_CHECK([ovs-ofctl add-flow br0 action=1])
> +AT_CHECK([ovs-ofctl add-flow int-br1 action=2])
> +AT_CHECK([ovs-ofctl add-flow int-br2 action=3])
> +AT_CHECK([ovs-ofctl add-flow int-br3 action=4])
> +
> +dnl Check "srv6_flowlabel=copy".
> +AT_CHECK([ovs-appctl netdev-dummy/receive int-br1 
> 'in_port(2),eth(src=f8:bc:12:44:34:b6,dst=aa:55:aa:55:00:00),eth_type(0x0800),ipv4(src=10.0.0.1,dst=10.0.0.2,proto=1,tos=0,ttl=64,frag=no),icmp(type=8,code=0)'])
> +AT_CHECK([ovs-appctl netdev-dummy/receive int-br1 
> 'in_port(2),eth(src=f8:bc:12:44:34:b6,dst=aa:55:aa:55:00:00),eth_type(0x0800),ipv4(src=10.0.0.1,dst=10.0.0.3,proto=1,tos=0,ttl=64,frag=no),icmp(type=8,code=0)'])
> +AT_CHECK([ovs-appctl netdev-dummy/receive int-br1 
> 'in_port(2),eth(src=f8:bc:12:44:34:b6,dst=aa:55:aa:55:00:00),eth_type(0x86dd),ipv6(src=2001:beef::1,dst=2001:beef::2,label=2,proto=47,tclass=0x0,hlimit=64)'])
> +AT_CHECK([ovs-appctl netdev-dummy/receive int-br1 
> 'in_port(2),eth(src=f8:bc:12:44:34:b6,dst=aa:55:aa:55:00:00),eth_type(0x86dd),ipv6(src=2001:beef::1,dst=2001:beef::3,label=3,proto=47,tclass=0x0,hlimit=64)'])
> +AT_CHECK([ovs-ofctl parse-pcap p0.pcap | tail -n 4 | grep -o 
> 'ipv6_label=0x[[0-9a-f]]*'], [0], [dnl
> +ipv6_label=0x00000
> +ipv6_label=0x00000
> +ipv6_label=0x00002
> +ipv6_label=0x00003
> +])
> +
> +dnl Check "srv6_flowlabel=zero".
> +AT_CHECK([ovs-appctl netdev-dummy/receive int-br2 
> 'in_port(3),eth(src=f8:bc:12:44:34:b6,dst=aa:55:aa:55:00:00),eth_type(0x0800),ipv4(src=10.0.0.1,dst=10.0.0.2,proto=1,tos=0,ttl=64,frag=no),icmp(type=8,code=0)'])
> +AT_CHECK([ovs-appctl netdev-dummy/receive int-br2 
> 'in_port(3),eth(src=f8:bc:12:44:34:b6,dst=aa:55:aa:55:00:00),eth_type(0x0800),ipv4(src=10.0.0.1,dst=10.0.0.3,proto=1,tos=0,ttl=64,frag=no),icmp(type=8,code=0)'])
> +AT_CHECK([ovs-appctl netdev-dummy/receive int-br2 
> 'in_port(3),eth(src=f8:bc:12:44:34:b6,dst=aa:55:aa:55:00:00),eth_type(0x86dd),ipv6(src=2001:beef::1,dst=2001:beef::2,label=2,proto=47,tclass=0x0,hlimit=64)'])
> +AT_CHECK([ovs-appctl netdev-dummy/receive int-br2 
> 'in_port(3),eth(src=f8:bc:12:44:34:b6,dst=aa:55:aa:55:00:00),eth_type(0x86dd),ipv6(src=2001:beef::1,dst=2001:beef::3,label=3,proto=47,tclass=0x0,hlimit=64)'])
> +AT_CHECK([ovs-ofctl parse-pcap p0.pcap | tail -n 4 | grep -o 
> 'ipv6_label=0x[[0-9a-f]]*'], [0], [dnl
> +ipv6_label=0x00000
> +ipv6_label=0x00000
> +ipv6_label=0x00000
> +ipv6_label=0x00000
> +])
> +
> +dnl dnl Check "srv6_flowlabel=compute".
> +AT_CHECK([ovs-appctl netdev-dummy/receive int-br3 
> 'in_port(4),eth(src=f8:bc:12:44:34:b6,dst=aa:55:aa:55:00:00),eth_type(0x0800),ipv4(src=10.0.0.1,dst=10.0.0.2,proto=1,tos=0,ttl=64,frag=no),icmp(type=8,code=0)'])
> +AT_CHECK([ovs-appctl netdev-dummy/receive int-br3 
> 'in_port(4),eth(src=f8:bc:12:44:34:b6,dst=aa:55:aa:55:00:00),eth_type(0x0800),ipv4(src=10.0.0.1,dst=10.0.0.3,proto=1,tos=0,ttl=64,frag=no),icmp(type=8,code=0)'])
> +AT_CHECK([ovs-appctl netdev-dummy/receive int-br3 
> 'in_port(4),eth(src=f8:bc:12:44:34:b6,dst=aa:55:aa:55:00:00),eth_type(0x86dd),ipv6(src=2001:beef::1,dst=2001:beef::2,label=2,proto=47,tclass=0x0,hlimit=64)'])
> +AT_CHECK([ovs-appctl netdev-dummy/receive int-br3 
> 'in_port(4),eth(src=f8:bc:12:44:34:b6,dst=aa:55:aa:55:00:00),eth_type(0x86dd),ipv6(src=2001:beef::1,dst=2001:beef::3,label=3,proto=47,tclass=0x0,hlimit=64)'])
> +AT_CHECK([ovs-ofctl parse-pcap p0.pcap | tail -n 4 | grep -o 
> 'ipv6_label=0x[[0-9a-f]]*'| sort | uniq -c | wc -l], [0], [dnl
> +4

So, you're sending 4 different packets and checking that they have
different labels.  However, you're not testing that two packets
from the same flow have the same hash.  Might be good to add a check
like this.

> +])
> +
> +OVS_VSWITCHD_STOP
> +AT_CLEANUP
> +
>  AT_SETUP([tunnel_push_pop_ipv6 - ip6gre])
>  
>  OVS_VSWITCHD_START([add-port br0 p0 -- set Interface p0 type=dummy 
> ofport_request=1 other-config:hwaddr=aa:55:aa:55:00:00])
> diff --git a/vswitchd/vswitch.xml b/vswitchd/vswitch.xml
> index edb5eafa04c3..8bcc361e8c62 100644
> --- a/vswitchd/vswitch.xml
> +++ b/vswitchd/vswitch.xml
> @@ -3287,6 +3287,32 @@
>             <ref column="options" key="remote_ip"/>.
>          </p>
>        </column>
> +      <column name="options" key="srv6_flowlabel"
> +              type='{"type": "string",
> +                     "enum": ["set", ["zero", "copy", "compute"]]}'>
> +        <p>
> +          Optional.
> +          This option controls how flowlabel in outer IPv6 header is
> +          configured. It gives the benefit of IPv6 flow label based
> +          load balancing, which is supported by some popular vendor
> +          appliances. Like net.ipv6.seg6_flowlabel sysconfig, it is
> +          one of the three values below:
> +        </p>
> +        <ul>
> +          <li>
> +            By default, or if this option is <code>copy</code>, copy the
> +            flowlabel of inner IPv6 header to the flowlabel of outer IPv6
> +            header. If inner header is not IPv6, it is set to 0.
> +          </li>
> +          <li>
> +            If this option is <code>zero</code>, simply set flowlabel to 0.
> +          </li>
> +          <li>
> +            If this option is <code>compute</code>, set RSS hash of inner
> +            packet to flowlabel.

Same here.  We shouldn't mention RSS, we should say that it's a hash
over L3/L4 fields of the inner packet.

> +          </li>
> +        </ul>
> +      </column>
>      </group>
>  
>      <group title="Patch Options">

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