net: ipv4: Hook into time based transmission

Add a transmit_time field to struct inet_cork, then copy the
timestamp from the CMSG cookie at ip_setup_cork() so we can
safely copy it into the skb later during __ip_make_skb().

For the raw fast path, just perform the copy at raw_send_hdrinc().
Signed-off-by: Richard Cochran <rcochran@linutronix.de>
Signed-off-by: Jesus Sanchez-Palencia <jesus.sanchez-palencia@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/inet_sock.h

@@ -148,6 +148,7 @@ struct inet_cork {
 	__s16			tos;
 	char			priority;
 	__u16			gso_size;
+	u64			transmit_time;
 };
 
 struct inet_cork_full {

net/ipv4/icmp.c

@@ -437,6 +437,7 @@ static void icmp_reply(struct icmp_bxm *icmp_param, struct sk_buff *skb)
 	ipc.tx_flags = 0;
 	ipc.ttl = 0;
 	ipc.tos = -1;
+	ipc.sockc.transmit_time = 0;
 
 	if (icmp_param->replyopts.opt.opt.optlen) {
 		ipc.opt = &icmp_param->replyopts.opt;
@@ -715,6 +716,7 @@ void icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info)
 	ipc.tx_flags = 0;
 	ipc.ttl = 0;
 	ipc.tos = -1;
+	ipc.sockc.transmit_time = 0;
 
 	rt = icmp_route_lookup(net, &fl4, skb_in, iph, saddr, tos, mark,
 			       type, code, &icmp_param);

net/ipv4/ip_output.c

@@ -1154,6 +1154,7 @@ static int ip_setup_cork(struct sock *sk, struct inet_cork *cork,
 	cork->tos = ipc->tos;
 	cork->priority = ipc->priority;
 	cork->tx_flags = ipc->tx_flags;
+	cork->transmit_time = ipc->sockc.transmit_time;
 
 	return 0;
 }
@@ -1414,6 +1415,7 @@ struct sk_buff *__ip_make_skb(struct sock *sk,
 
 	skb->priority = (cork->tos != -1) ? cork->priority: sk->sk_priority;
 	skb->mark = sk->sk_mark;
+	skb->tstamp = cork->transmit_time;
 	/*
 	 * Steal rt from cork.dst to avoid a pair of atomic_inc/atomic_dec
 	 * on dst refcount
@@ -1551,6 +1553,7 @@ void ip_send_unicast_reply(struct sock *sk, struct sk_buff *skb,
 	ipc.tx_flags = 0;
 	ipc.ttl = 0;
 	ipc.tos = -1;
+	ipc.sockc.transmit_time = 0;
 
 	if (replyopts.opt.opt.optlen) {
 		ipc.opt = &replyopts.opt;

net/ipv4/ping.c

@@ -746,6 +746,7 @@ static int ping_v4_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 	ipc.tx_flags = 0;
 	ipc.ttl = 0;
 	ipc.tos = -1;
+	ipc.sockc.transmit_time = 0;
 
 	if (msg->msg_controllen) {
 		err = ip_cmsg_send(sk, msg, &ipc, false);

net/ipv4/raw.c

@@ -381,6 +381,7 @@ static int raw_send_hdrinc(struct sock *sk, struct flowi4 *fl4,
 
 	skb->priority = sk->sk_priority;
 	skb->mark = sk->sk_mark;
+	skb->tstamp = sockc->transmit_time;
 	skb_dst_set(skb, &rt->dst);
 	*rtp = NULL;
 
@@ -562,6 +563,7 @@ static int raw_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 	}
 
 	ipc.sockc.tsflags = sk->sk_tsflags;
+	ipc.sockc.transmit_time = 0;
 	ipc.addr = inet->inet_saddr;
 	ipc.opt = NULL;
 	ipc.tx_flags = 0;

net/ipv4/udp.c

@@ -930,6 +930,7 @@ int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 	ipc.tx_flags = 0;
 	ipc.ttl = 0;
 	ipc.tos = -1;
+	ipc.sockc.transmit_time = 0;
 
 	getfrag = is_udplite ? udplite_getfrag : ip_generic_getfrag;