target/linux/generic/pending-3.18/081-01-pppoe-Use-workqueue-to-die-properly-when-a-PADT-is-r.patch

   1 From: Simon Farnsworth <simon@farnz.org.uk>
   2 Date: Sun, 1 Mar 2015 10:54:39 +0000
   3 Subject: [PATCH] pppoe: Use workqueue to die properly when a PADT is received
   4
   5 When a PADT frame is received, the socket may not be in a good state to
   6 close down the PPP interface. The current implementation handles this by
   7 simply blocking all further PPP traffic, and hoping that the lack of traffic
   8 will trigger the user to investigate.
   9
  10 Use schedule_work to get to a process context from which we clear down the
  11 PPP interface, in a fashion analogous to hangup on a TTY-based PPP
  12 interface. This causes pppd to disconnect immediately, and allows tools to
  13 take immediate corrective action.
  14
  15 Note that pppd's rp_pppoe.so plugin has code in it to disable the session
  16 when it disconnects; however, as a consequence of this patch, the session is
  17 already disabled before rp_pppoe.so is asked to disable the session. The
  18 result is a harmless error message:
  19
  20 Failed to disconnect PPPoE socket: 114 Operation already in progress
  21
  22 This message is safe to ignore, as long as the error is 114 Operation
  23 already in progress; in that specific case, it means that the PPPoE session
  24 has already been disabled before pppd tried to disable it.
  25
  26 Signed-off-by: Simon Farnsworth <simon@farnz.org.uk>
  27 Tested-by: Dan Williams <dcbw@redhat.com>
  28 Tested-by: Christoph Schulz <develop@kristov.de>
  29 Signed-off-by: David S. Miller <davem@davemloft.net>
  30 ---
  31
  32 --- a/drivers/net/ppp/pppoe.c
  33 +++ b/drivers/net/ppp/pppoe.c
  34 @@ -454,6 +454,18 @@ out:
  35         return NET_RX_DROP;
  36  }
  37
  38 +static void pppoe_unbind_sock_work(struct work_struct *work)
  39 +{
  40 +       struct pppox_sock *po = container_of(work, struct pppox_sock,
  41 +                                            proto.pppoe.padt_work);
  42 +       struct sock *sk = sk_pppox(po);
  43 +
  44 +       lock_sock(sk);
  45 +       pppox_unbind_sock(sk);
  46 +       release_sock(sk);
  47 +       sock_put(sk);
  48 +}
  49 +
  50  /************************************************************************
  51   *
  52   * Receive a PPPoE Discovery frame.
  53 @@ -499,7 +511,8 @@ static int pppoe_disc_rcv(struct sk_buff
  54                 }
  55
  56                 bh_unlock_sock(sk);
  57 -               sock_put(sk);
  58 +               if (!schedule_work(&po->proto.pppoe.padt_work))
  59 +                       sock_put(sk);
  60         }
  61
  62  abort:
  63 @@ -612,6 +625,8 @@ static int pppoe_connect(struct socket *
  64
  65         lock_sock(sk);
  66
  67 +       INIT_WORK(&po->proto.pppoe.padt_work, pppoe_unbind_sock_work);
  68 +
  69         error = -EINVAL;
  70         if (sp->sa_protocol != PX_PROTO_OE)
  71                 goto end;
  72 --- a/include/linux/if_pppox.h
  73 +++ b/include/linux/if_pppox.h
  74 @@ -19,6 +19,7 @@
  75  #include <linux/netdevice.h>
  76  #include <linux/ppp_channel.h>
  77  #include <linux/skbuff.h>
  78 +#include <linux/workqueue.h>
  79  #include <uapi/linux/if_pppox.h>
  80
  81  static inline struct pppoe_hdr *pppoe_hdr(const struct sk_buff *skb)
  82 @@ -32,6 +33,7 @@ struct pppoe_opt {
  83         struct pppoe_addr       pa;       /* what this socket is bound to*/
  84         struct sockaddr_pppox   relay;    /* what socket data will be
  85                                              relayed to (PPPoE relaying) */
  86 +       struct work_struct      padt_work;/* Work item for handling PADT */
  87  };
  88
  89  struct pptp_opt {