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Date: Tue, 22 Aug 2017 17:08:48 -0400
From: Mike Maloney <maloneykernel@...il.com>
To: netdev@...r.kernel.org, davem@...emloft.net
Cc: willemdebruijn.kernel@...il.com, soheil@...gle.com,
Mike Maloney <maloney@...gle.com>
Subject: [PATCH v2 net-next 1/2] tcp: Extend SOF_TIMESTAMPING_RX_SOFTWARE to TCP recvmsg
From: Mike Maloney <maloney@...gle.com>
When SOF_TIMESTAMPING_RX_SOFTWARE is enabled for tcp sockets, return the
timestamp corresponding to the highest sequence number data returned.
Previously the skb->tstamp is overwritten when a TCP packet is placed
in the out of order queue. While the packet is in the ooo queue, save the
timestamp in the TCB_SKB_CB. This space is shared with the gso_*
options which are only used on the tx path, and a previously unused 4
byte hole.
When skbs are coalesced either in the sk_receive_queue or the
out_of_order_queue always choose the timestamp of the appended skb to
maintain the invariant of returning the timestamp of the last byte in
the recvmsg buffer.
Signed-off-by: Mike Maloney <maloney@...gle.com>
---
include/net/tcp.h | 9 +++++++-
net/ipv4/tcp.c | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++++
net/ipv4/tcp_input.c | 35 ++++++++++++++++++++++++----
net/ipv4/tcp_ipv4.c | 2 ++
net/ipv6/tcp_ipv6.c | 2 ++
5 files changed, 108 insertions(+), 5 deletions(-)
diff --git a/include/net/tcp.h b/include/net/tcp.h
index afdab3781425..f26d20e9760d 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -774,6 +774,12 @@ struct tcp_skb_cb {
u16 tcp_gso_segs;
u16 tcp_gso_size;
};
+
+ /* Used to stash the receive timestamp while this skb is in the
+ * out of order queue, as skb->tstamp is overwritten by the
+ * rbnode.
+ */
+ ktime_t swtstamp;
};
__u8 tcp_flags; /* TCP header flags. (tcp[13]) */
@@ -790,7 +796,8 @@ struct tcp_skb_cb {
__u8 ip_dsfield; /* IPv4 tos or IPv6 dsfield */
__u8 txstamp_ack:1, /* Record TX timestamp for ack? */
eor:1, /* Is skb MSG_EOR marked? */
- unused:6;
+ has_rxtstamp:1, /* SKB has a RX timestamp */
+ unused:5;
__u32 ack_seq; /* Sequence number ACK'd */
union {
struct {
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index d25e3bcca66b..0cce4472b4a1 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -269,6 +269,7 @@
#include <linux/err.h>
#include <linux/time.h>
#include <linux/slab.h>
+#include <linux/errqueue.h>
#include <net/icmp.h>
#include <net/inet_common.h>
@@ -1695,6 +1696,61 @@ int tcp_peek_len(struct socket *sock)
}
EXPORT_SYMBOL(tcp_peek_len);
+static void tcp_update_recv_tstamps(struct sk_buff *skb,
+ struct scm_timestamping *tss)
+{
+ if (skb->tstamp)
+ tss->ts[0] = ktime_to_timespec(skb->tstamp);
+ else
+ tss->ts[0] = (struct timespec) {0};
+
+ if (skb_hwtstamps(skb)->hwtstamp)
+ tss->ts[2] = ktime_to_timespec(skb_hwtstamps(skb)->hwtstamp);
+ else
+ tss->ts[2] = (struct timespec) {0};
+}
+
+/* Similar to __sock_recv_timestamp, but does not require an skb */
+void tcp_recv_timestamp(struct msghdr *msg, const struct sock *sk,
+ struct scm_timestamping *tss)
+{
+ struct timeval tv;
+ bool has_timestamping = false;
+
+ if (tss->ts[0].tv_sec || tss->ts[0].tv_nsec) {
+ if (sock_flag(sk, SOCK_RCVTSTAMP)) {
+ if (sock_flag(sk, SOCK_RCVTSTAMPNS)) {
+ put_cmsg(msg, SOL_SOCKET, SCM_TIMESTAMPNS,
+ sizeof(tss->ts[0]), &tss->ts[0]);
+ } else {
+ tv.tv_sec = tss->ts[0].tv_sec;
+ tv.tv_usec = tss->ts[0].tv_nsec / 1000;
+
+ put_cmsg(msg, SOL_SOCKET, SCM_TIMESTAMP,
+ sizeof(tv), &tv);
+ }
+ }
+
+ if (sk->sk_tsflags & SOF_TIMESTAMPING_SOFTWARE)
+ has_timestamping = true;
+ else
+ tss->ts[0] = (struct timespec) {0};
+ }
+
+ if (tss->ts[2].tv_sec || tss->ts[2].tv_nsec) {
+ if (sk->sk_tsflags & SOF_TIMESTAMPING_RAW_HARDWARE)
+ has_timestamping = true;
+ else
+ tss->ts[2] = (struct timespec) {0};
+ }
+
+ if (has_timestamping) {
+ tss->ts[1] = (struct timespec) {0};
+ put_cmsg(msg, SOL_SOCKET, SCM_TIMESTAMPING,
+ sizeof(*tss), tss);
+ }
+}
+
/*
* This routine copies from a sock struct into the user buffer.
*
@@ -1716,6 +1772,8 @@ int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock,
long timeo;
struct sk_buff *skb, *last;
u32 urg_hole = 0;
+ struct scm_timestamping tss;
+ bool has_tss = false;
if (unlikely(flags & MSG_ERRQUEUE))
return inet_recv_error(sk, msg, len, addr_len);
@@ -1911,6 +1969,10 @@ int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock,
if (used + offset < skb->len)
continue;
+ if (TCP_SKB_CB(skb)->has_rxtstamp) {
+ tcp_update_recv_tstamps(skb, &tss);
+ has_tss = true;
+ }
if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
goto found_fin_ok;
if (!(flags & MSG_PEEK))
@@ -1929,6 +1991,9 @@ int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock,
* on connected socket. I was just happy when found this 8) --ANK
*/
+ if (has_tss)
+ tcp_recv_timestamp(msg, sk, &tss);
+
/* Clean up data we have read: This will do ACK frames. */
tcp_cleanup_rbuf(sk, copied);
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index ddc854728a60..66abcbf6f381 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -4246,9 +4246,15 @@ static void tcp_sack_remove(struct tcp_sock *tp)
tp->rx_opt.num_sacks = num_sacks;
}
+enum tcp_queue {
+ OOO_QUEUE,
+ RCV_QUEUE,
+};
+
/**
* tcp_try_coalesce - try to merge skb to prior one
* @sk: socket
+ * @dest: destination queue
* @to: prior buffer
* @from: buffer to add in queue
* @fragstolen: pointer to boolean
@@ -4260,6 +4266,7 @@ static void tcp_sack_remove(struct tcp_sock *tp)
* Returns true if caller should free @from instead of queueing it
*/
static bool tcp_try_coalesce(struct sock *sk,
+ enum tcp_queue dest,
struct sk_buff *to,
struct sk_buff *from,
bool *fragstolen)
@@ -4281,6 +4288,15 @@ static bool tcp_try_coalesce(struct sock *sk,
TCP_SKB_CB(to)->end_seq = TCP_SKB_CB(from)->end_seq;
TCP_SKB_CB(to)->ack_seq = TCP_SKB_CB(from)->ack_seq;
TCP_SKB_CB(to)->tcp_flags |= TCP_SKB_CB(from)->tcp_flags;
+
+ if (TCP_SKB_CB(from)->has_rxtstamp) {
+ TCP_SKB_CB(to)->has_rxtstamp = true;
+ if (dest == OOO_QUEUE)
+ TCP_SKB_CB(to)->swtstamp = TCP_SKB_CB(from)->swtstamp;
+ else
+ to->tstamp = from->tstamp;
+ }
+
return true;
}
@@ -4315,6 +4331,9 @@ static void tcp_ofo_queue(struct sock *sk)
}
p = rb_next(p);
rb_erase(&skb->rbnode, &tp->out_of_order_queue);
+ /* Replace tstamp which was stomped by rbnode */
+ if (TCP_SKB_CB(skb)->has_rxtstamp)
+ skb->tstamp = TCP_SKB_CB(skb)->swtstamp;
if (unlikely(!after(TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt))) {
SOCK_DEBUG(sk, "ofo packet was already received\n");
@@ -4326,7 +4345,8 @@ static void tcp_ofo_queue(struct sock *sk)
TCP_SKB_CB(skb)->end_seq);
tail = skb_peek_tail(&sk->sk_receive_queue);
- eaten = tail && tcp_try_coalesce(sk, tail, skb, &fragstolen);
+ eaten = tail && tcp_try_coalesce(sk, RCV_QUEUE,
+ tail, skb, &fragstolen);
tcp_rcv_nxt_update(tp, TCP_SKB_CB(skb)->end_seq);
fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN;
if (!eaten)
@@ -4380,6 +4400,10 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb)
return;
}
+ /* Stash tstamp to avoid being stomped on by rbnode */
+ if (TCP_SKB_CB(skb)->has_rxtstamp)
+ TCP_SKB_CB(skb)->swtstamp = skb->tstamp;
+
inet_csk_schedule_ack(sk);
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPOFOQUEUE);
@@ -4405,7 +4429,8 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb)
/* In the typical case, we are adding an skb to the end of the list.
* Use of ooo_last_skb avoids the O(Log(N)) rbtree lookup.
*/
- if (tcp_try_coalesce(sk, tp->ooo_last_skb, skb, &fragstolen)) {
+ if (tcp_try_coalesce(sk, OOO_QUEUE, tp->ooo_last_skb,
+ skb, &fragstolen)) {
coalesce_done:
tcp_grow_window(sk, skb);
kfree_skb_partial(skb, fragstolen);
@@ -4455,7 +4480,8 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb)
__kfree_skb(skb1);
goto merge_right;
}
- } else if (tcp_try_coalesce(sk, skb1, skb, &fragstolen)) {
+ } else if (tcp_try_coalesce(sk, OOO_QUEUE, skb1,
+ skb, &fragstolen)) {
goto coalesce_done;
}
p = &parent->rb_right;
@@ -4506,7 +4532,8 @@ static int __must_check tcp_queue_rcv(struct sock *sk, struct sk_buff *skb, int
__skb_pull(skb, hdrlen);
eaten = (tail &&
- tcp_try_coalesce(sk, tail, skb, fragstolen)) ? 1 : 0;
+ tcp_try_coalesce(sk, RCV_QUEUE, tail,
+ skb, fragstolen)) ? 1 : 0;
tcp_rcv_nxt_update(tcp_sk(sk), TCP_SKB_CB(skb)->end_seq);
if (!eaten) {
__skb_queue_tail(&sk->sk_receive_queue, skb);
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 5af8b809dfbc..a63486afa7a7 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1637,6 +1637,8 @@ int tcp_v4_rcv(struct sk_buff *skb)
TCP_SKB_CB(skb)->tcp_tw_isn = 0;
TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
TCP_SKB_CB(skb)->sacked = 0;
+ TCP_SKB_CB(skb)->has_rxtstamp =
+ skb->tstamp || skb_hwtstamps(skb)->hwtstamp;
lookup:
sk = __inet_lookup_skb(&tcp_hashinfo, skb, __tcp_hdrlen(th), th->source,
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index d79a1af3252e..abba3bc2a3d9 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1394,6 +1394,8 @@ static void tcp_v6_fill_cb(struct sk_buff *skb, const struct ipv6hdr *hdr,
TCP_SKB_CB(skb)->tcp_tw_isn = 0;
TCP_SKB_CB(skb)->ip_dsfield = ipv6_get_dsfield(hdr);
TCP_SKB_CB(skb)->sacked = 0;
+ TCP_SKB_CB(skb)->has_rxtstamp =
+ skb->tstamp || skb_hwtstamps(skb)->hwtstamp;
}
static int tcp_v6_rcv(struct sk_buff *skb)
--
2.14.1.480.gb18f417b89-goog
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