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authorWillem de Bruijn <willemb@google.com>2015-01-30 13:29:31 -0500
committerDavid S. Miller <davem@davemloft.net>2015-02-02 18:46:51 -0800
commit49ca0d8bfaf3bc46d5eef60ce67b00eb195bd392 (patch)
treed2f55a32923f6d91fcb2e0d0e0b6d2d4eb6f9abd /net/core
parent9766e97af1b901ffbb36fcc648e50626d926bb24 (diff)
downloadlinux-49ca0d8bfaf3bc46d5eef60ce67b00eb195bd392.tar.bz2
net-timestamp: no-payload option
Add timestamping option SOF_TIMESTAMPING_OPT_TSONLY. For transmit timestamps, this loops timestamps on top of empty packets. Doing so reduces the pressure on SO_RCVBUF. Payload inspection and cmsg reception (aside from timestamps) are no longer possible. This works together with a follow on patch that allows administrators to only allow tx timestamping if it does not loop payload or metadata. Signed-off-by: Willem de Bruijn <willemb@google.com> ---- Changes (rfc -> v1) - add documentation - remove unnecessary skb->len test (thanks to Richard Cochran) Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core')
-rw-r--r--net/core/skbuff.c19
1 files changed, 14 insertions, 5 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 56db472e9b86..65a3798f43e6 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3710,19 +3710,28 @@ void __skb_tstamp_tx(struct sk_buff *orig_skb,
struct sock *sk, int tstype)
{
struct sk_buff *skb;
+ bool tsonly = sk->sk_tsflags & SOF_TIMESTAMPING_OPT_TSONLY;
if (!sk)
return;
- if (hwtstamps)
- *skb_hwtstamps(orig_skb) = *hwtstamps;
+ if (tsonly)
+ skb = alloc_skb(0, GFP_ATOMIC);
else
- orig_skb->tstamp = ktime_get_real();
-
- skb = skb_clone(orig_skb, GFP_ATOMIC);
+ skb = skb_clone(orig_skb, GFP_ATOMIC);
if (!skb)
return;
+ if (tsonly) {
+ skb_shinfo(skb)->tx_flags = skb_shinfo(orig_skb)->tx_flags;
+ skb_shinfo(skb)->tskey = skb_shinfo(orig_skb)->tskey;
+ }
+
+ if (hwtstamps)
+ *skb_hwtstamps(skb) = *hwtstamps;
+ else
+ skb->tstamp = ktime_get_real();
+
__skb_complete_tx_timestamp(skb, sk, tstype);
}
EXPORT_SYMBOL_GPL(__skb_tstamp_tx);