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/packet/af_packet.c b/net/packet/af_packet.c
index 1ecfa71..0007e23 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -1837,6 +1837,7 @@
DECLARE_SOCKADDR(struct sockaddr_pkt *, saddr, msg->msg_name);
struct sk_buff *skb = NULL;
struct net_device *dev;
+ struct sockcm_cookie sockc;
__be16 proto = 0;
int err;
int extra_len = 0;
@@ -1925,12 +1926,21 @@
goto out_unlock;
}
+ sockc.tsflags = 0;
+ if (msg->msg_controllen) {
+ err = sock_cmsg_send(sk, msg, &sockc);
+ if (unlikely(err)) {
+ err = -EINVAL;
+ goto out_unlock;
+ }
+ }
+
skb->protocol = proto;
skb->dev = dev;
skb->priority = sk->sk_priority;
skb->mark = sk->sk_mark;
- sock_tx_timestamp(sk, &skb_shinfo(skb)->tx_flags);
+ sock_tx_timestamp(sk, sockc.tsflags, &skb_shinfo(skb)->tx_flags);
if (unlikely(extra_len == 4))
skb->no_fcs = 1;
@@ -2486,7 +2496,8 @@
static int tpacket_fill_skb(struct packet_sock *po, struct sk_buff *skb,
void *frame, struct net_device *dev, void *data, int tp_len,
- __be16 proto, unsigned char *addr, int hlen, int copylen)
+ __be16 proto, unsigned char *addr, int hlen, int copylen,
+ const struct sockcm_cookie *sockc)
{
union tpacket_uhdr ph;
int to_write, offset, len, nr_frags, len_max;
@@ -2500,7 +2511,7 @@
skb->dev = dev;
skb->priority = po->sk.sk_priority;
skb->mark = po->sk.sk_mark;
- sock_tx_timestamp(&po->sk, &skb_shinfo(skb)->tx_flags);
+ sock_tx_timestamp(&po->sk, sockc->tsflags, &skb_shinfo(skb)->tx_flags);
skb_shinfo(skb)->destructor_arg = ph.raw;
skb_reserve(skb, hlen);
@@ -2624,6 +2635,7 @@
struct sk_buff *skb;
struct net_device *dev;
struct virtio_net_hdr *vnet_hdr = NULL;
+ struct sockcm_cookie sockc;
__be16 proto;
int err, reserve = 0;
void *ph;
@@ -2655,6 +2667,13 @@
dev = dev_get_by_index(sock_net(&po->sk), saddr->sll_ifindex);
}
+ sockc.tsflags = 0;
+ if (msg->msg_controllen) {
+ err = sock_cmsg_send(&po->sk, msg, &sockc);
+ if (unlikely(err))
+ goto out;
+ }
+
err = -ENXIO;
if (unlikely(dev == NULL))
goto out;
@@ -2712,7 +2731,7 @@
goto out_status;
}
tp_len = tpacket_fill_skb(po, skb, ph, dev, data, tp_len, proto,
- addr, hlen, copylen);
+ addr, hlen, copylen, &sockc);
if (likely(tp_len >= 0) &&
tp_len > dev->mtu + reserve &&
!po->has_vnet_hdr &&
@@ -2851,6 +2870,7 @@
if (unlikely(!(dev->flags & IFF_UP)))
goto out_unlock;
+ sockc.tsflags = 0;
sockc.mark = sk->sk_mark;
if (msg->msg_controllen) {
err = sock_cmsg_send(sk, msg, &sockc);
@@ -2908,7 +2928,7 @@
goto out_free;
}
- sock_tx_timestamp(sk, &skb_shinfo(skb)->tx_flags);
+ sock_tx_timestamp(sk, sockc.tsflags, &skb_shinfo(skb)->tx_flags);
if (!vnet_hdr.gso_type && (len > dev->mtu + reserve + extra_len) &&
!packet_extra_vlan_len_allowed(dev, skb)) {