net/core/timestamping.c

   1 /*
   2  * PTP 1588 clock support - support for timestamping in PHY devices
   3  *
   4  * Copyright (C) 2010 OMICRON electronics GmbH
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; either version 2 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19  */
  20 #include <linux/errqueue.h>
  21 #include <linux/phy.h>
  22 #include <linux/ptp_classify.h>
  23 #include <linux/skbuff.h>
  24 #include <linux/export.h>
  25
  26 static unsigned int classify(const struct sk_buff *skb)
  27 {
  28         if (likely(skb->dev && skb->dev->phydev &&
  29                    skb->dev->phydev->drv))
  30                 return ptp_classify_raw(skb);
  31         else
  32                 return PTP_CLASS_NONE;
  33 }
  34
  35 void skb_clone_tx_timestamp(struct sk_buff *skb)
  36 {
  37         struct phy_device *phydev;
  38         struct sk_buff *clone;
  39         struct sock *sk = skb->sk;
  40         unsigned int type;
  41
  42         if (!sk)
  43                 return;
  44
  45         type = classify(skb);
  46         if (type == PTP_CLASS_NONE)
  47                 return;
  48
  49         phydev = skb->dev->phydev;
  50         if (likely(phydev->drv->txtstamp)) {
  51                 if (!atomic_inc_not_zero(&sk->sk_refcnt))
  52                         return;
  53
  54                 clone = skb_clone(skb, GFP_ATOMIC);
  55                 if (!clone) {
  56                         sock_put(sk);
  57                         return;
  58                 }
  59
  60                 clone->sk = sk;
  61                 phydev->drv->txtstamp(phydev, clone, type);
  62         }
  63 }
  64 EXPORT_SYMBOL_GPL(skb_clone_tx_timestamp);
  65
  66 void skb_complete_tx_timestamp(struct sk_buff *skb,
  67                                struct skb_shared_hwtstamps *hwtstamps)
  68 {
  69         struct sock *sk = skb->sk;
  70         struct sock_exterr_skb *serr;
  71         int err;
  72
  73         if (!hwtstamps) {
  74                 sock_put(sk);
  75                 kfree_skb(skb);
  76                 return;
  77         }
  78
  79         *skb_hwtstamps(skb) = *hwtstamps;
  80
  81         serr = SKB_EXT_ERR(skb);
  82         memset(serr, 0, sizeof(*serr));
  83         serr->ee.ee_errno = ENOMSG;
  84         serr->ee.ee_origin = SO_EE_ORIGIN_TIMESTAMPING;
  85         skb->sk = NULL;
  86
  87         err = sock_queue_err_skb(sk, skb);
  88
  89         sock_put(sk);
  90         if (err)
  91                 kfree_skb(skb);
  92 }
  93 EXPORT_SYMBOL_GPL(skb_complete_tx_timestamp);
  94
  95 bool skb_defer_rx_timestamp(struct sk_buff *skb)
  96 {
  97         struct phy_device *phydev;
  98         unsigned int type;
  99
 100         if (skb_headroom(skb) < ETH_HLEN)
 101                 return false;
 102         __skb_push(skb, ETH_HLEN);
 103
 104         type = classify(skb);
 105
 106         __skb_pull(skb, ETH_HLEN);
 107
 108         if (type == PTP_CLASS_NONE)
 109                 return false;
 110
 111         phydev = skb->dev->phydev;
 112         if (likely(phydev->drv->rxtstamp))
 113                 return phydev->drv->rxtstamp(phydev, skb, type);
 114
 115         return false;
 116 }
 117 EXPORT_SYMBOL_GPL(skb_defer_rx_timestamp);