[TCP]: Add pluggable congestion control algorithm infrastructure.

Allow TCP to have multiple pluggable congestion control algorithms.
Algorithms are defined by a set of operations and can be built in
or modules.  The legacy "new RENO" algorithm is used as a starting
point and fallback.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 8 insertions, 15 deletions

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index f17c6577e337..0e17c244875c 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -111,8 +111,7 @@ static void tcp_cwnd_restart(struct tcp_sock *tp, struct dst_entry *dst)
         u32 restart_cwnd = tcp_init_cwnd(tp, dst);
         u32 cwnd = tp->snd_cwnd;
 
-        if (tcp_is_vegas(tp)) 
-                tcp_vegas_enable(tp);
+        tcp_ca_event(tp, CA_EVENT_CWND_RESTART);
 
         tp->snd_ssthresh = tcp_current_ssthresh(tp);
         restart_cwnd = min(restart_cwnd, cwnd);
@@ -280,6 +279,10 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb)
 #define SYSCTL_FLAG_WSCALE      0x2
 #define SYSCTL_FLAG_SACK        0x4
 
+                /* If congestion control is doing timestamping */
+                if (tp->ca_ops->rtt_sample)
+                        do_gettimeofday(&skb->stamp);
+
                 sysctl_flags = 0;
                 if (tcb->flags & TCPCB_FLAG_SYN) {
                         tcp_header_size = sizeof(struct tcphdr) + TCPOLEN_MSS;
@@ -304,17 +307,8 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb)
                                             (tp->rx_opt.eff_sacks * TCPOLEN_SACK_PERBLOCK));
                 }
                 
-                /*
-                 * If the connection is idle and we are restarting,
-                 * then we don't want to do any Vegas calculations
-                 * until we get fresh RTT samples.  So when we
-                 * restart, we reset our Vegas state to a clean
-                 * slate. After we get acks for this flight of
-                 * packets, _then_ we can make Vegas calculations
-                 * again.
-                 */
-                if (tcp_is_vegas(tp) && tcp_packets_in_flight(tp) == 0)
-                        tcp_vegas_enable(tp);
+                if (tcp_packets_in_flight(tp) == 0)
+                        tcp_ca_event(tp, CA_EVENT_TX_START);
 
                 th = (struct tcphdr *) skb_push(skb, tcp_header_size);
                 skb->h.th = th;
@@ -521,6 +515,7 @@ static int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len)
          * skbs, which it never sent before. --ANK
          */
         TCP_SKB_CB(buff)->when = TCP_SKB_CB(skb)->when;
+        buff->stamp = skb->stamp;
 
         if (TCP_SKB_CB(skb)->sacked & TCPCB_LOST) {
                 tp->lost_out -= tcp_skb_pcount(skb);
@@ -1449,7 +1444,6 @@ static inline void tcp_connect_init(struct sock *sk)
                 tp->window_clamp = dst_metric(dst, RTAX_WINDOW);
         tp->advmss = dst_metric(dst, RTAX_ADVMSS);
         tcp_initialize_rcv_mss(sk);
-        tcp_ca_init(tp);
 
         tcp_select_initial_window(tcp_full_space(sk),
                                   tp->advmss - (tp->rx_opt.ts_recent_stamp ? tp->tcp_header_len - sizeof(struct tcphdr) : 0),
@@ -1503,7 +1497,6 @@ int tcp_connect(struct sock *sk)
         TCP_SKB_CB(buff)->end_seq = tp->write_seq;
         tp->snd_nxt = tp->write_seq;
         tp->pushed_seq = tp->write_seq;
-        tcp_ca_init(tp);
 
         /* Send it off. */
         TCP_SKB_CB(buff)->when = tcp_time_stamp;