[PATCH 4.10 37/62] tcp: mark skbs with SCM_TIMESTAMPING_OPT_STATS

From: Greg Kroah-Hartman
Date: Mon May 01 2017 - 17:42:32 EST


4.10-stable review patch. If anyone has any objections, please let me know.

------------------

From: Soheil Hassas Yeganeh <soheil@xxxxxxxxxx>


[ Upstream commit 4ef1b2869447411ad3ef91ad7d4891a83c1a509a ]

SOF_TIMESTAMPING_OPT_STATS can be enabled and disabled
while packets are collected on the error queue.
So, checking SOF_TIMESTAMPING_OPT_STATS in sk->sk_tsflags
is not enough to safely assume that the skb contains
OPT_STATS data.

Add a bit in sock_exterr_skb to indicate whether the
skb contains opt_stats data.

Fixes: 1c885808e456 ("tcp: SOF_TIMESTAMPING_OPT_STATS option for SO_TIMESTAMPING")
Reported-by: JongHwan Kim <zzoru007@xxxxxxxxx>
Signed-off-by: Soheil Hassas Yeganeh <soheil@xxxxxxxxxx>
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: Willem de Bruijn <willemb@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
include/linux/errqueue.h | 2 ++
net/core/skbuff.c | 17 +++++++++++------
net/socket.c | 2 +-
3 files changed, 14 insertions(+), 7 deletions(-)

--- a/include/linux/errqueue.h
+++ b/include/linux/errqueue.h
@@ -20,6 +20,8 @@ struct sock_exterr_skb {
struct sock_extended_err ee;
u16 addr_offset;
__be16 port;
+ u8 opt_stats:1,
+ unused:7;
};

#endif
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3799,16 +3799,20 @@ EXPORT_SYMBOL(skb_clone_sk);

static void __skb_complete_tx_timestamp(struct sk_buff *skb,
struct sock *sk,
- int tstype)
+ int tstype,
+ bool opt_stats)
{
struct sock_exterr_skb *serr;
int err;

+ BUILD_BUG_ON(sizeof(struct sock_exterr_skb) > sizeof(skb->cb));
+
serr = SKB_EXT_ERR(skb);
memset(serr, 0, sizeof(*serr));
serr->ee.ee_errno = ENOMSG;
serr->ee.ee_origin = SO_EE_ORIGIN_TIMESTAMPING;
serr->ee.ee_info = tstype;
+ serr->opt_stats = opt_stats;
serr->header.h4.iif = skb->dev ? skb->dev->ifindex : 0;
if (sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID) {
serr->ee.ee_data = skb_shinfo(skb)->tskey;
@@ -3850,7 +3854,7 @@ void skb_complete_tx_timestamp(struct sk
*/
if (likely(atomic_inc_not_zero(&sk->sk_refcnt))) {
*skb_hwtstamps(skb) = *hwtstamps;
- __skb_complete_tx_timestamp(skb, sk, SCM_TSTAMP_SND);
+ __skb_complete_tx_timestamp(skb, sk, SCM_TSTAMP_SND, false);
sock_put(sk);
}
}
@@ -3861,7 +3865,7 @@ void __skb_tstamp_tx(struct sk_buff *ori
struct sock *sk, int tstype)
{
struct sk_buff *skb;
- bool tsonly;
+ bool tsonly, opt_stats = false;

if (!sk)
return;
@@ -3874,9 +3878,10 @@ void __skb_tstamp_tx(struct sk_buff *ori
#ifdef CONFIG_INET
if ((sk->sk_tsflags & SOF_TIMESTAMPING_OPT_STATS) &&
sk->sk_protocol == IPPROTO_TCP &&
- sk->sk_type == SOCK_STREAM)
+ sk->sk_type == SOCK_STREAM) {
skb = tcp_get_timestamping_opt_stats(sk);
- else
+ opt_stats = true;
+ } else
#endif
skb = alloc_skb(0, GFP_ATOMIC);
} else {
@@ -3895,7 +3900,7 @@ void __skb_tstamp_tx(struct sk_buff *ori
else
skb->tstamp = ktime_get_real();

- __skb_complete_tx_timestamp(skb, sk, tstype);
+ __skb_complete_tx_timestamp(skb, sk, tstype, opt_stats);
}
EXPORT_SYMBOL_GPL(__skb_tstamp_tx);

--- a/net/socket.c
+++ b/net/socket.c
@@ -708,7 +708,7 @@ void __sock_recv_timestamp(struct msghdr
SCM_TIMESTAMPING, sizeof(tss), &tss);

if (skb_is_err_queue(skb) && skb->len &&
- (sk->sk_tsflags & SOF_TIMESTAMPING_OPT_STATS))
+ SKB_EXT_ERR(skb)->opt_stats)
put_cmsg(msg, SOL_SOCKET, SCM_TIMESTAMPING_OPT_STATS,
skb->len, skb->data);
}