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sock: enable timestamping using control messages

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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>
This commit is contained in:
Soheil Hassas Yeganeh
2016-04-02 23:08:12 -04:00
committed by David S. Miller
parent ad1e46a837
commit c14ac9451c
16 changed files with 93 additions and 49 deletions
Download Patch File Download Diff File Expand all files Collapse all files

20
net/ipv4/tcp.c
View File

@@ -428,13 +428,13 @@ void tcp_init_sock(struct sock *sk)
}
EXPORT_SYMBOL(tcp_init_sock);
static void tcp_tx_timestamp(struct sock *sk, struct sk_buff *skb)
static void tcp_tx_timestamp(struct sock *sk, u16 tsflags, struct sk_buff *skb)
{
if (sk->sk_tsflags) {
if (sk->sk_tsflags || tsflags) {
struct skb_shared_info *shinfo = skb_shinfo(skb);
struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
sock_tx_timestamp(sk, &shinfo->tx_flags);
sock_tx_timestamp(sk, tsflags, &shinfo->tx_flags);
if (shinfo->tx_flags & SKBTX_ANY_TSTAMP)
shinfo->tskey = TCP_SKB_CB(skb)->seq + skb->len - 1;
tcb->txstamp_ack = !!(shinfo->tx_flags & SKBTX_ACK_TSTAMP);
@@ -959,7 +959,7 @@ new_segment:
offset += copy;
size -= copy;
if (!size) {
tcp_tx_timestamp(sk, skb);
tcp_tx_timestamp(sk, sk->sk_tsflags, skb);
goto out;
}
@@ -1079,6 +1079,7 @@ int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
{
struct tcp_sock *tp = tcp_sk(sk);
struct sk_buff *skb;
struct sockcm_cookie sockc;
int flags, err, copied = 0;
int mss_now = 0, size_goal, copied_syn = 0;
bool sg;
@@ -1121,6 +1122,15 @@ int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
/* 'common' sending to sendq */
}
sockc.tsflags = sk->sk_tsflags;
if (msg->msg_controllen) {
err = sock_cmsg_send(sk, msg, &sockc);
if (unlikely(err)) {
err = -EINVAL;
goto out_err;
}
}
/* This should be in poll */
sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
@@ -1239,7 +1249,7 @@ new_segment:
copied += copy;
if (!msg_data_left(msg)) {
tcp_tx_timestamp(sk, skb);
tcp_tx_timestamp(sk, sockc.tsflags, skb);
goto out;
}