Re: [PATCHv3 net-next] udp: call udp_encap_enable for v6 sockets when enabling encap

[Xin Long]

On Tue, Jan 26, 2021 at 10:35 AM Willem de Bruijn
<willemdebruijn.ker...@gmail.com> wrote:
>
> On Sun, Jan 24, 2021 at 3:57 AM Xin Long <lucien....@gmail.com> wrote:
> >
> > When enabling encap for a ipv6 socket without udp_encap_needed_key
> > increased, UDP GRO won't work for v4 mapped v6 address packets as
> > sk will be NULL in udp4_gro_receive().
> >
> > This patch is to enable it by increasing udp_encap_needed_key for
> > v6 sockets in udp_tunnel_encap_enable(), and correspondingly
> > decrease udp_encap_needed_key in udpv6_destroy_sock().
> >
> > v1->v2:
> >   - add udp_encap_disable() and export it.
> > v2->v3:
> >   - add the change for rxrpc and bareudp into one patch, as Alex
> >     suggested.
> >
> > Signed-off-by: Xin Long <lucien....@gmail.com>
> > ---
> >  drivers/net/bareudp.c    | 6 ------
> >  include/net/udp.h        | 1 +
> >  include/net/udp_tunnel.h | 3 +--
> >  net/ipv4/udp.c           | 6 ++++++
> >  net/ipv6/udp.c           | 4 +++-
> >  net/rxrpc/local_object.c | 4 +++-
> >  6 files changed, 14 insertions(+), 10 deletions(-)
> >
> > diff --git a/drivers/net/bareudp.c b/drivers/net/bareudp.c
> > index 1b8f597..7511bca 100644
> > --- a/drivers/net/bareudp.c
> > +++ b/drivers/net/bareudp.c
> > @@ -240,12 +240,6 @@ static int bareudp_socket_create(struct bareudp_dev 
> > *bareudp, __be16 port)
> >         tunnel_cfg.encap_destroy = NULL;
> >         setup_udp_tunnel_sock(bareudp->net, sock, &tunnel_cfg);
> >
> > -       /* As the setup_udp_tunnel_sock does not call udp_encap_enable if 
> > the
> > -        * socket type is v6 an explicit call to udp_encap_enable is needed.
> > -        */
> > -       if (sock->sk->sk_family == AF_INET6)
> > -               udp_encap_enable();
> > -
> >         rcu_assign_pointer(bareudp->sock, sock);
> >         return 0;
> >  }
> > diff --git a/include/net/udp.h b/include/net/udp.h
> > index 877832b..1e7b6cd 100644
> > --- a/include/net/udp.h
> > +++ b/include/net/udp.h
> > @@ -467,6 +467,7 @@ void udp_init(void);
> >
> >  DECLARE_STATIC_KEY_FALSE(udp_encap_needed_key);
> >  void udp_encap_enable(void);
> > +void udp_encap_disable(void);
> >  #if IS_ENABLED(CONFIG_IPV6)
> >  DECLARE_STATIC_KEY_FALSE(udpv6_encap_needed_key);
> >  void udpv6_encap_enable(void);
> > diff --git a/include/net/udp_tunnel.h b/include/net/udp_tunnel.h
> > index 282d10e..afc7ce7 100644
> > --- a/include/net/udp_tunnel.h
> > +++ b/include/net/udp_tunnel.h
> > @@ -181,9 +181,8 @@ static inline void udp_tunnel_encap_enable(struct 
> > socket *sock)
> >  #if IS_ENABLED(CONFIG_IPV6)
> >         if (sock->sk->sk_family == PF_INET6)
> >                 ipv6_stub->udpv6_encap_enable();
> > -       else
> >  #endif
> > -               udp_encap_enable();
> > +       udp_encap_enable();
> >  }
> >
> >  #define UDP_TUNNEL_NIC_MAX_TABLES      4
> > diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
> > index 69ea765..48208fb 100644
> > --- a/net/ipv4/udp.c
> > +++ b/net/ipv4/udp.c
> > @@ -596,6 +596,12 @@ void udp_encap_enable(void)
> >  }
> >  EXPORT_SYMBOL(udp_encap_enable);
> >
> > +void udp_encap_disable(void)
> > +{
> > +       static_branch_dec(&udp_encap_needed_key);
> > +}
> > +EXPORT_SYMBOL(udp_encap_disable);
> > +
> >  /* Handler for tunnels with arbitrary destination ports: no socket lookup, 
> > go
> >   * through error handlers in encapsulations looking for a match.
> >   */
> > diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
> > index b9f3dfd..d754292 100644
> > --- a/net/ipv6/udp.c
> > +++ b/net/ipv6/udp.c
> > @@ -1608,8 +1608,10 @@ void udpv6_destroy_sock(struct sock *sk)
> >                         if (encap_destroy)
> >                                 encap_destroy(sk);
> >                 }
> > -               if (up->encap_enabled)
> > +               if (up->encap_enabled) {
> >                         static_branch_dec(&udpv6_encap_needed_key);
> > +                       udp_encap_disable();
> > +               }
> >         }
> >
> >         inet6_destroy_sock(sk);
> > diff --git a/net/rxrpc/local_object.c b/net/rxrpc/local_object.c
> > index 8c28810..fc10234 100644
> > --- a/net/rxrpc/local_object.c
> > +++ b/net/rxrpc/local_object.c
> > @@ -135,11 +135,13 @@ static int rxrpc_open_socket(struct rxrpc_local 
> > *local, struct net *net)
> >         udp_sk(usk)->gro_receive = NULL;
> >         udp_sk(usk)->gro_complete = NULL;
> >
> > -       udp_encap_enable();
> >  #if IS_ENABLED(CONFIG_AF_RXRPC_IPV6)
> >         if (local->srx.transport.family == AF_INET6)
> >                 udpv6_encap_enable();
> > +       else
> >  #endif
> > +               udp_encap_enable();
> > +
>
> If ipv6 this socket will decrement both static branches in
> udpv6_destroy_sock. Shouldn't it increment both, then? Similar to
> udp_tunnel_encap_enable, but open coded.
My mistake, all above should just call udp_tunnel_encap_enable(),
otherwise, it won't be decreased in udpv6_destroy_sock(). will respost.

Thanks.