[Intel-wired-lan] [net-next PATCH 01/15] net: Combine GENEVE and VXLAN port offload notifiers into single functions

Alexander Duyck alexander.duyck at gmail.com
Mon Jun 13 20:24:41 UTC 2016


On Mon, Jun 13, 2016 at 12:55 PM, Tom Herbert <tom at herbertland.com> wrote:
> On Mon, Jun 13, 2016 at 10:47 AM, Alexander Duyck <aduyck at mirantis.com> wrote:
>> This patch merges the GENEVE and VXLAN code so that both functions pass
>> through a shared code path.  This way we can start the effort of using a
>> single function on the network device drivers to handle both of these
>> tunnel offload types.
>>
>> Signed-off-by: Alexander Duyck <aduyck at mirantis.com>
>> ---
>>  drivers/net/geneve.c     |   48 ++++-------------------------
>>  drivers/net/vxlan.c      |   46 ++++-----------------------
>>  include/net/udp_tunnel.h |   12 +++++++
>>  net/ipv4/udp_tunnel.c    |   77 ++++++++++++++++++++++++++++++++++++++++++++++
>>  4 files changed, 103 insertions(+), 80 deletions(-)
>>
>> diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c
>> index cadefe4fdaa2..f5ce41532cf4 100644
>> --- a/drivers/net/geneve.c
>> +++ b/drivers/net/geneve.c
>> @@ -399,19 +399,7 @@ static struct socket *geneve_create_sock(struct net *net, bool ipv6,
>>
>>  static void geneve_notify_add_rx_port(struct geneve_sock *gs)
>>  {
>> -       struct net_device *dev;
>> -       struct sock *sk = gs->sock->sk;
>> -       struct net *net = sock_net(sk);
>> -       sa_family_t sa_family = geneve_get_sk_family(gs);
>> -       __be16 port = inet_sk(sk)->inet_sport;
>> -
>> -       rcu_read_lock();
>> -       for_each_netdev_rcu(net, dev) {
>> -               if (dev->netdev_ops->ndo_add_geneve_port)
>> -                       dev->netdev_ops->ndo_add_geneve_port(dev, sa_family,
>> -                                                            port);
>> -       }
>> -       rcu_read_unlock();
>> +       udp_tunnel_notify_add_rx_port(gs->sock, UDP_ENC_OFFLOAD_TYPE_GENEVE);
>>  }
>>
>>  static int geneve_hlen(struct genevehdr *gh)
>> @@ -550,20 +538,7 @@ static struct geneve_sock *geneve_socket_create(struct net *net, __be16 port,
>>
>>  static void geneve_notify_del_rx_port(struct geneve_sock *gs)
>>  {
>> -       struct net_device *dev;
>> -       struct sock *sk = gs->sock->sk;
>> -       struct net *net = sock_net(sk);
>> -       sa_family_t sa_family = geneve_get_sk_family(gs);
>> -       __be16 port = inet_sk(sk)->inet_sport;
>> -
>> -       rcu_read_lock();
>> -       for_each_netdev_rcu(net, dev) {
>> -               if (dev->netdev_ops->ndo_del_geneve_port)
>> -                       dev->netdev_ops->ndo_del_geneve_port(dev, sa_family,
>> -                                                            port);
>> -       }
>> -
>> -       rcu_read_unlock();
>> +       udp_tunnel_notify_add_rx_port(gs->sock, UDP_ENC_OFFLOAD_TYPE_GENEVE);
>>  }
>>
>>  static void __geneve_sock_release(struct geneve_sock *gs)
>> @@ -1165,29 +1140,20 @@ static struct device_type geneve_type = {
>>         .name = "geneve",
>>  };
>>
>> -/* Calls the ndo_add_geneve_port of the caller in order to
>> +/* Calls the ndo_add_udp_enc_port of the caller in order to
>>   * supply the listening GENEVE udp ports. Callers are expected
>> - * to implement the ndo_add_geneve_port.
>> + * to implement the ndo_add_udp_enc_port.
>>   */
>>  static void geneve_push_rx_ports(struct net_device *dev)
>>  {
>>         struct net *net = dev_net(dev);
>>         struct geneve_net *gn = net_generic(net, geneve_net_id);
>>         struct geneve_sock *gs;
>> -       sa_family_t sa_family;
>> -       struct sock *sk;
>> -       __be16 port;
>> -
>> -       if (!dev->netdev_ops->ndo_add_geneve_port)
>> -               return;
>>
>>         rcu_read_lock();
>> -       list_for_each_entry_rcu(gs, &gn->sock_list, list) {
>> -               sk = gs->sock->sk;
>> -               sa_family = sk->sk_family;
>> -               port = inet_sk(sk)->inet_sport;
>> -               dev->netdev_ops->ndo_add_geneve_port(dev, sa_family, port);
>> -       }
>> +       list_for_each_entry_rcu(gs, &gn->sock_list, list)
>> +               udp_tunnel_push_rx_port(dev, gs->sock,
>> +                                       UDP_ENC_OFFLOAD_TYPE_GENEVE);
>>         rcu_read_unlock();
>>  }
>>
>> diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
>> index f999db2f97b4..43f634282726 100644
>> --- a/drivers/net/vxlan.c
>> +++ b/drivers/net/vxlan.c
>> @@ -622,37 +622,13 @@ static int vxlan_gro_complete(struct sock *sk, struct sk_buff *skb, int nhoff)
>>  /* Notify netdevs that UDP port started listening */
>>  static void vxlan_notify_add_rx_port(struct vxlan_sock *vs)
>>  {
>> -       struct net_device *dev;
>> -       struct sock *sk = vs->sock->sk;
>> -       struct net *net = sock_net(sk);
>> -       sa_family_t sa_family = vxlan_get_sk_family(vs);
>> -       __be16 port = inet_sk(sk)->inet_sport;
>> -
>> -       rcu_read_lock();
>> -       for_each_netdev_rcu(net, dev) {
>> -               if (dev->netdev_ops->ndo_add_vxlan_port)
>> -                       dev->netdev_ops->ndo_add_vxlan_port(dev, sa_family,
>> -                                                           port);
>> -       }
>> -       rcu_read_unlock();
>> +       udp_tunnel_notify_add_rx_port(vs->sock, UDP_ENC_OFFLOAD_TYPE_VXLAN);
>>  }
>>
>>  /* Notify netdevs that UDP port is no more listening */
>>  static void vxlan_notify_del_rx_port(struct vxlan_sock *vs)
>>  {
>> -       struct net_device *dev;
>> -       struct sock *sk = vs->sock->sk;
>> -       struct net *net = sock_net(sk);
>> -       sa_family_t sa_family = vxlan_get_sk_family(vs);
>> -       __be16 port = inet_sk(sk)->inet_sport;
>> -
>> -       rcu_read_lock();
>> -       for_each_netdev_rcu(net, dev) {
>> -               if (dev->netdev_ops->ndo_del_vxlan_port)
>> -                       dev->netdev_ops->ndo_del_vxlan_port(dev, sa_family,
>> -                                                           port);
>> -       }
>> -       rcu_read_unlock();
>> +       udp_tunnel_notify_del_rx_port(vs->sock, UDP_ENC_OFFLOAD_TYPE_VXLAN);
>>  }
>>
>>  /* Add new entry to forwarding table -- assumes lock held */
>> @@ -2525,30 +2501,22 @@ static struct device_type vxlan_type = {
>>         .name = "vxlan",
>>  };
>>
>> -/* Calls the ndo_add_vxlan_port of the caller in order to
>> +/* Calls the ndo_add_udp_enc_port of the caller in order to
>>   * supply the listening VXLAN udp ports. Callers are expected
>> - * to implement the ndo_add_vxlan_port.
>> + * to implement the ndo_add_udp_enc_port.
>>   */
>>  static void vxlan_push_rx_ports(struct net_device *dev)
>>  {
>>         struct vxlan_sock *vs;
>>         struct net *net = dev_net(dev);
>>         struct vxlan_net *vn = net_generic(net, vxlan_net_id);
>> -       sa_family_t sa_family;
>> -       __be16 port;
>>         unsigned int i;
>>
>> -       if (!dev->netdev_ops->ndo_add_vxlan_port)
>> -               return;
>> -
>>         spin_lock(&vn->sock_lock);
>>         for (i = 0; i < PORT_HASH_SIZE; ++i) {
>> -               hlist_for_each_entry_rcu(vs, &vn->sock_list[i], hlist) {
>> -                       port = inet_sk(vs->sock->sk)->inet_sport;
>> -                       sa_family = vxlan_get_sk_family(vs);
>> -                       dev->netdev_ops->ndo_add_vxlan_port(dev, sa_family,
>> -                                                           port);
>> -               }
>> +               hlist_for_each_entry_rcu(vs, &vn->sock_list[i], hlist)
>> +                       udp_tunnel_push_rx_port(dev, vs->sock,
>> +                                               UDP_ENC_OFFLOAD_TYPE_VXLAN);
>>         }
>>         spin_unlock(&vn->sock_lock);
>>  }
>> diff --git a/include/net/udp_tunnel.h b/include/net/udp_tunnel.h
>> index 9d14f707e534..704f931fd9ad 100644
>> --- a/include/net/udp_tunnel.h
>> +++ b/include/net/udp_tunnel.h
>> @@ -84,6 +84,18 @@ struct udp_tunnel_sock_cfg {
>>  void setup_udp_tunnel_sock(struct net *net, struct socket *sock,
>>                            struct udp_tunnel_sock_cfg *sock_cfg);
>>
>> +/* List of offloadable UDP tunnel types */
>> +enum udp_enc_offloads {
>> +       UDP_ENC_OFFLOAD_TYPE_VXLAN,     /* RFC 7348 */
>> +       UDP_ENC_OFFLOAD_TYPE_GENEVE,    /* draft-ietf-nvo3-geneve */
>> +};
>> +
> We've already had a lot of discussion on this. The clear outcome from
> netdev was that we need to support generic offloads and move away from
> protocol specific offload. Generalizing the interface to allow vendors
> to unnecessarily leak out protocol specific features undermines that
> effort.

Then in turn we get dirty hacks like what we have right now where
VXLAN-GPE is attempting to reuse the VXLAN offload functions or
drivers that just hard-code GENEVE ports.

Going full obstructionist on this isn't going to work.  We need to be
able to support these type of offloads because the switch vendors are
going to force the NIC vendors to do so.  We will likely never be able
to convince Cisco to implement an outer transmit checksum on their
switches.  In order to make offloads work without the outer checksum
we will need to be able to parse the frames in order to be able to
validate the inner checksum values.

At this point what we need to focus on is being able to show that this
feature is essentially a crutch.  To that end I really think we need
to focus on enabling Tx checksum for all new UDP tunnels going forward
by default.  That way we get the full benefits of the offload before
we even have to start thinking about adding this kind of code.  It
isn't until we start having to deal with switches and other OSes that
cannot support the outer checksum on Tx that we need these kind of
workarounds in the hardware.

- Alex


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