tcp: add a struct net parameter to tcp_parse_options()

We want to move some TCP sysctls to net namespaces in the future.

tcp_window_scaling, tcp_sack and tcp_timestamps being fetched
from tcp_parse_options(), we need to pass an extra parameter.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 4ea8ec5..99ee707 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -3724,7 +3724,8 @@ static void tcp_parse_fastopen_option(int len, const unsigned char *cookie,
  * But, this can also be called on packets in the established flow when
  * the fast version below fails.
  */
-void tcp_parse_options(const struct sk_buff *skb,
+void tcp_parse_options(const struct net *net,
+		       const struct sk_buff *skb,
 		       struct tcp_options_received *opt_rx, int estab,
 		       struct tcp_fastopen_cookie *foc)
 {
@@ -3858,7 +3859,8 @@ static bool tcp_parse_aligned_timestamp(struct tcp_sock *tp, const struct tcphdr
 /* Fast parse options. This hopes to only see timestamps.
  * If it is wrong it falls back on tcp_parse_options().
  */
-static bool tcp_fast_parse_options(const struct sk_buff *skb,
+static bool tcp_fast_parse_options(const struct net *net,
+				   const struct sk_buff *skb,
 				   const struct tcphdr *th, struct tcp_sock *tp)
 {
 	/* In the spirit of fast parsing, compare doff directly to constant
@@ -3873,7 +3875,7 @@ static bool tcp_fast_parse_options(const struct sk_buff *skb,
 			return true;
 	}
 
-	tcp_parse_options(skb, &tp->rx_opt, 1, NULL);
+	tcp_parse_options(net, skb, &tp->rx_opt, 1, NULL);
 	if (tp->rx_opt.saw_tstamp && tp->rx_opt.rcv_tsecr)
 		tp->rx_opt.rcv_tsecr -= tp->tsoffset;
 
@@ -5234,7 +5236,8 @@ static bool tcp_validate_incoming(struct sock *sk, struct sk_buff *skb,
 	bool rst_seq_match = false;
 
 	/* RFC1323: H1. Apply PAWS check first. */
-	if (tcp_fast_parse_options(skb, th, tp) && tp->rx_opt.saw_tstamp &&
+	if (tcp_fast_parse_options(sock_net(sk), skb, th, tp) &&
+	    tp->rx_opt.saw_tstamp &&
 	    tcp_paws_discard(sk, skb)) {
 		if (!th->rst) {
 			NET_INC_STATS(sock_net(sk), LINUX_MIB_PAWSESTABREJECTED);
@@ -5605,7 +5608,7 @@ static bool tcp_rcv_fastopen_synack(struct sock *sk, struct sk_buff *synack,
 		/* Get original SYNACK MSS value if user MSS sets mss_clamp */
 		tcp_clear_options(&opt);
 		opt.user_mss = opt.mss_clamp = 0;
-		tcp_parse_options(synack, &opt, 0, NULL);
+		tcp_parse_options(sock_net(sk), synack, &opt, 0, NULL);
 		mss = opt.mss_clamp;
 	}
 
@@ -5659,7 +5662,7 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
 	int saved_clamp = tp->rx_opt.mss_clamp;
 	bool fastopen_fail;
 
-	tcp_parse_options(skb, &tp->rx_opt, 0, &foc);
+	tcp_parse_options(sock_net(sk), skb, &tp->rx_opt, 0, &foc);
 	if (tp->rx_opt.saw_tstamp && tp->rx_opt.rcv_tsecr)
 		tp->rx_opt.rcv_tsecr -= tp->tsoffset;
 
@@ -6332,7 +6335,8 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops,
 	tcp_clear_options(&tmp_opt);
 	tmp_opt.mss_clamp = af_ops->mss_clamp;
 	tmp_opt.user_mss  = tp->rx_opt.user_mss;
-	tcp_parse_options(skb, &tmp_opt, 0, want_cookie ? NULL : &foc);
+	tcp_parse_options(sock_net(sk), skb, &tmp_opt, 0,
+			  want_cookie ? NULL : &foc);
 
 	if (want_cookie && !tmp_opt.saw_tstamp)
 		tcp_clear_options(&tmp_opt);