sock: enable timestamping using control messages
Currently, SOL_TIMESTAMPING can only be enabled using setsockopt.
This is very costly when users want to sample writes to gather
tx timestamps.
Add support for enabling SO_TIMESTAMPING via control messages by
using tsflags added in `struct sockcm_cookie` (added in the previous
patches in this series) to set the tx_flags of the last skb created in
a sendmsg. With this patch, the timestamp recording bits in tx_flags
of the skbuff is overridden if SO_TIMESTAMPING is passed in a cmsg.
Please note that this is only effective for overriding the recording
timestamps flags. Users should enable timestamp reporting (e.g.,
SOF_TIMESTAMPING_SOFTWARE | SOF_TIMESTAMPING_OPT_ID) using
socket options and then should ask for SOF_TIMESTAMPING_TX_*
using control messages per sendmsg to sample timestamps for each
write.
Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 2a787af..b772a76 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -1248,7 +1248,7 @@
fl6.flowi6_oif = np->sticky_pktinfo.ipi6_ifindex;
fl6.flowi6_mark = sk->sk_mark;
- sockc.tsflags = 0;
+ sockc.tsflags = sk->sk_tsflags;
if (msg->msg_controllen) {
opt = &opt_space;
@@ -1324,7 +1324,7 @@
skb = ip6_make_skb(sk, getfrag, msg, ulen,
sizeof(struct udphdr), hlimit, tclass, opt,
&fl6, (struct rt6_info *)dst,
- msg->msg_flags, dontfrag);
+ msg->msg_flags, dontfrag, &sockc);
err = PTR_ERR(skb);
if (!IS_ERR_OR_NULL(skb))
err = udp_v6_send_skb(skb, &fl6);
@@ -1351,7 +1351,8 @@
err = ip6_append_data(sk, getfrag, msg, ulen,
sizeof(struct udphdr), hlimit, tclass, opt, &fl6,
(struct rt6_info *)dst,
- corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags, dontfrag);
+ corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags, dontfrag,
+ &sockc);
if (err)
udp_v6_flush_pending_frames(sk);
else if (!corkreq)