net: Abstract default ADVMSS behind an accessor.

[cascardo/linux.git] / net / ipv4 / tcp_output.c

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 05b1ecf..2d39066 100644 (file)
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -55,7 +55,7 @@ int sysctl_tcp_workaround_signed_windows __read_mostly = 0;
 int sysctl_tcp_tso_win_divisor __read_mostly = 3;
 
 int sysctl_tcp_mtu_probing __read_mostly = 0;
-int sysctl_tcp_base_mss __read_mostly = 512;
+int sysctl_tcp_base_mss __read_mostly = TCP_BASE_MSS;
 
 /* By default, RFC2861 behavior.  */
 int sysctl_tcp_slow_start_after_idle __read_mostly = 1;
@@ -119,9 +119,13 @@ static __u16 tcp_advertise_mss(struct sock *sk)
        struct dst_entry *dst = __sk_dst_get(sk);
        int mss = tp->advmss;
 
-       if (dst && dst_metric(dst, RTAX_ADVMSS) < mss) {
-               mss = dst_metric(dst, RTAX_ADVMSS);
-               tp->advmss = mss;
+       if (dst) {
+               unsigned int metric = dst_metric_advmss(dst);
+
+               if (metric < mss) {
+                       mss = metric;
+                       tp->advmss = mss;
+               }
        }
 
        return (__u16)mss;
@@ -231,11 +235,10 @@ void tcp_select_initial_window(int __space, __u32 mss,
                /* when initializing use the value from init_rcv_wnd
                 * rather than the default from above
                 */
-               if (init_rcv_wnd &&
-                   (*rcv_wnd > init_rcv_wnd * mss))
-                       *rcv_wnd = init_rcv_wnd * mss;
-               else if (*rcv_wnd > init_cwnd * mss)
-                       *rcv_wnd = init_cwnd * mss;
+               if (init_rcv_wnd)
+                       *rcv_wnd = min(*rcv_wnd, init_rcv_wnd * mss);
+               else
+                       *rcv_wnd = min(*rcv_wnd, init_cwnd * mss);
        }
 
        /* Set the clamp no higher than max representable value */
@@ -386,27 +389,30 @@ struct tcp_out_options {
  */
 static u8 tcp_cookie_size_check(u8 desired)
 {
-       if (desired > 0) {
+       int cookie_size;
+
+       if (desired > 0)
                /* previously specified */
                return desired;
-       }
-       if (sysctl_tcp_cookie_size <= 0) {
+
+       cookie_size = ACCESS_ONCE(sysctl_tcp_cookie_size);
+       if (cookie_size <= 0)
                /* no default specified */
                return 0;
-       }
-       if (sysctl_tcp_cookie_size <= TCP_COOKIE_MIN) {
+
+       if (cookie_size <= TCP_COOKIE_MIN)
                /* value too small, specify minimum */
                return TCP_COOKIE_MIN;
-       }
-       if (sysctl_tcp_cookie_size >= TCP_COOKIE_MAX) {
+
+       if (cookie_size >= TCP_COOKIE_MAX)
                /* value too large, specify maximum */
                return TCP_COOKIE_MAX;
-       }
-       if (0x1 & sysctl_tcp_cookie_size) {
+
+       if (cookie_size & 1)
                /* 8-bit multiple, illegal, fix it */
-               return (u8)(sysctl_tcp_cookie_size + 0x1);
-       }
-       return (u8)sysctl_tcp_cookie_size;
+               cookie_size++;
+
+       return (u8)cookie_size;
 }
 
 /* Write previously computed TCP options to the packet.
@@ -822,8 +828,11 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it,
                                                           &md5);
        tcp_header_size = tcp_options_size + sizeof(struct tcphdr);
 
-       if (tcp_packets_in_flight(tp) == 0)
+       if (tcp_packets_in_flight(tp) == 0) {
                tcp_ca_event(sk, CA_EVENT_TX_START);
+               skb->ooo_okay = 1;
+       } else
+               skb->ooo_okay = 0;
 
        skb_push(skb, tcp_header_size);
        skb_reset_transport_header(skb);
@@ -1513,6 +1522,7 @@ static int tcp_tso_should_defer(struct sock *sk, struct sk_buff *skb)
        struct tcp_sock *tp = tcp_sk(sk);
        const struct inet_connection_sock *icsk = inet_csk(sk);
        u32 send_win, cong_win, limit, in_flight;
+       int win_divisor;
 
        if (TCP_SKB_CB(skb)->flags & TCPHDR_FIN)
                goto send_now;
@@ -1544,13 +1554,14 @@ static int tcp_tso_should_defer(struct sock *sk, struct sk_buff *skb)
        if ((skb != tcp_write_queue_tail(sk)) && (limit >= skb->len))
                goto send_now;
 
-       if (sysctl_tcp_tso_win_divisor) {
+       win_divisor = ACCESS_ONCE(sysctl_tcp_tso_win_divisor);
+       if (win_divisor) {
                u32 chunk = min(tp->snd_wnd, tp->snd_cwnd * tp->mss_cache);
 
                /* If at least some fraction of a window is available,
                 * just use it.
                 */
-               chunk /= sysctl_tcp_tso_win_divisor;
+               chunk /= win_divisor;
                if (limit >= chunk)
                        goto send_now;
        } else {
@@ -2415,7 +2426,7 @@ struct sk_buff *tcp_make_synack(struct sock *sk, struct dst_entry *dst,
 
        skb_dst_set(skb, dst_clone(dst));
 
-       mss = dst_metric(dst, RTAX_ADVMSS);
+       mss = dst_metric_advmss(dst);
        if (tp->rx_opt.user_mss && tp->rx_opt.user_mss < mss)
                mss = tp->rx_opt.user_mss;
 
@@ -2549,7 +2560,7 @@ static void tcp_connect_init(struct sock *sk)
 
        if (!tp->window_clamp)
                tp->window_clamp = dst_metric(dst, RTAX_WINDOW);
-       tp->advmss = dst_metric(dst, RTAX_ADVMSS);
+       tp->advmss = dst_metric_advmss(dst);
        if (tp->rx_opt.user_mss && tp->rx_opt.user_mss < tp->advmss)
                tp->advmss = tp->rx_opt.user_mss;
 
@@ -2592,6 +2603,7 @@ int tcp_connect(struct sock *sk)
 {
        struct tcp_sock *tp = tcp_sk(sk);
        struct sk_buff *buff;
+       int err;
 
        tcp_connect_init(sk);
 
@@ -2614,7 +2626,9 @@ int tcp_connect(struct sock *sk)
        sk->sk_wmem_queued += buff->truesize;
        sk_mem_charge(sk, buff->truesize);
        tp->packets_out += tcp_skb_pcount(buff);
-       tcp_transmit_skb(sk, buff, 1, sk->sk_allocation);
+       err = tcp_transmit_skb(sk, buff, 1, sk->sk_allocation);
+       if (err == -ECONNREFUSED)
+               return err;
 
        /* We change tp->snd_nxt after the tcp_transmit_skb() call
         * in order to make this packet get counted in tcpOutSegs.