tun: Support software transmit time stamping.

This patch adds transmit time stamping to the tun/tap driver. Similar
support already exists for UDP, can, and raw packets.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 15 insertions, 2 deletions

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index db690a372260..a72d141047cb 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -739,6 +739,11 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
                           >= dev->tx_queue_len / tun->numqueues)
                 goto drop;
 
+        if (skb->sk) {
+                sock_tx_timestamp(skb->sk, &skb_shinfo(skb)->tx_flags);
+                sw_tx_timestamp(skb);
+        }
+
         /* Orphan the skb - required as we might hang on to it
          * for indefinite time. */
         if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC)))
@@ -1476,7 +1481,6 @@ static int tun_sendmsg(struct kiocb *iocb, struct socket *sock,
         return ret;
 }
 
-
 static int tun_recvmsg(struct kiocb *iocb, struct socket *sock,
                        struct msghdr *m, size_t total_len,
                        int flags)
@@ -1488,10 +1492,15 @@ static int tun_recvmsg(struct kiocb *iocb, struct socket *sock,
         if (!tun)
                 return -EBADFD;
 
-        if (flags & ~(MSG_DONTWAIT|MSG_TRUNC)) {
+        if (flags & ~(MSG_DONTWAIT|MSG_TRUNC|MSG_ERRQUEUE)) {
                 ret = -EINVAL;
                 goto out;
         }
+        if (flags & MSG_ERRQUEUE) {
+                ret = sock_recv_errqueue(sock->sk, m, total_len,
+                                         SOL_PACKET, TUN_TX_TIMESTAMP);
+                goto out;
+        }
         ret = tun_do_read(tun, tfile, iocb, m->msg_iov, total_len,
                           flags & MSG_DONTWAIT);
         if (ret > total_len) {
@@ -2274,6 +2283,7 @@ static const struct ethtool_ops tun_ethtool_ops = {
         .get_msglevel   = tun_get_msglevel,
         .set_msglevel   = tun_set_msglevel,
         .get_link       = ethtool_op_get_link,
+        .get_ts_info    = ethtool_op_get_ts_info,
 };
 
 
diff --git a/include/uapi/linux/if_tun.h b/include/uapi/linux/if_tun.h
index 82334f88967e..1870ee29bb37 100644
--- a/include/uapi/linux/if_tun.h
+++ b/include/uapi/linux/if_tun.h
@@ -71,6 +71,9 @@
 /* read-only flag */
 #define IFF_PERSIST     0x0800
 
+/* Socket options */
+#define TUN_TX_TIMESTAMP 1
+
 /* Features for GSO (TUNSETOFFLOAD). */
 #define TUN_F_CSUM      0x01    /* You can hand me unchecksummed packets. */
 #define TUN_F_TSO4      0x02    /* I can handle TSO for IPv4 packets */