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Diffstat (limited to 'net/ipv4/tcp_yeah.h')
-rw-r--r--net/ipv4/tcp_yeah.h134
1 files changed, 134 insertions, 0 deletions
diff --git a/net/ipv4/tcp_yeah.h b/net/ipv4/tcp_yeah.h
new file mode 100644
index 00000000000..b3255dba4e2
--- /dev/null
+++ b/net/ipv4/tcp_yeah.h
@@ -0,0 +1,134 @@
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/inet_diag.h>
+
+#include <net/tcp.h>
+
+/* Vegas variables */
+struct vegas {
+ u32 beg_snd_nxt; /* right edge during last RTT */
+ u32 beg_snd_una; /* left edge during last RTT */
+ u32 beg_snd_cwnd; /* saves the size of the cwnd */
+ u8 doing_vegas_now;/* if true, do vegas for this RTT */
+ u16 cntRTT; /* # of RTTs measured within last RTT */
+ u32 minRTT; /* min of RTTs measured within last RTT (in usec) */
+ u32 baseRTT; /* the min of all Vegas RTT measurements seen (in usec) */
+};
+
+/* There are several situations when we must "re-start" Vegas:
+ *
+ * o when a connection is established
+ * o after an RTO
+ * o after fast recovery
+ * o when we send a packet and there is no outstanding
+ * unacknowledged data (restarting an idle connection)
+ *
+ * In these circumstances we cannot do a Vegas calculation at the
+ * end of the first RTT, because any calculation we do is using
+ * stale info -- both the saved cwnd and congestion feedback are
+ * stale.
+ *
+ * Instead we must wait until the completion of an RTT during
+ * which we actually receive ACKs.
+ */
+static inline void vegas_enable(struct sock *sk)
+{
+ const struct tcp_sock *tp = tcp_sk(sk);
+ struct vegas *vegas = inet_csk_ca(sk);
+
+ /* Begin taking Vegas samples next time we send something. */
+ vegas->doing_vegas_now = 1;
+
+ /* Set the beginning of the next send window. */
+ vegas->beg_snd_nxt = tp->snd_nxt;
+
+ vegas->cntRTT = 0;
+ vegas->minRTT = 0x7fffffff;
+}
+
+/* Stop taking Vegas samples for now. */
+static inline void vegas_disable(struct sock *sk)
+{
+ struct vegas *vegas = inet_csk_ca(sk);
+
+ vegas->doing_vegas_now = 0;
+}
+
+static void tcp_vegas_init(struct sock *sk)
+{
+ struct vegas *vegas = inet_csk_ca(sk);
+
+ vegas->baseRTT = 0x7fffffff;
+ vegas_enable(sk);
+}
+
+static void tcp_vegas_state(struct sock *sk, u8 ca_state)
+{
+
+ if (ca_state == TCP_CA_Open)
+ vegas_enable(sk);
+ else
+ vegas_disable(sk);
+}
+
+/* Do RTT sampling needed for Vegas.
+ * Basically we:
+ * o min-filter RTT samples from within an RTT to get the current
+ * propagation delay + queuing delay (we are min-filtering to try to
+ * avoid the effects of delayed ACKs)
+ * o min-filter RTT samples from a much longer window (forever for now)
+ * to find the propagation delay (baseRTT)
+ */
+static void tcp_vegas_rtt_calc(struct sock *sk, u32 usrtt)
+{
+ struct vegas *vegas = inet_csk_ca(sk);
+ u32 vrtt = usrtt + 1; /* Never allow zero rtt or baseRTT */
+
+ /* Filter to find propagation delay: */
+ if (vrtt < vegas->baseRTT)
+ vegas->baseRTT = vrtt;
+
+ /* Find the min RTT during the last RTT to find
+ * the current prop. delay + queuing delay:
+ */
+ vegas->minRTT = min(vegas->minRTT, vrtt);
+ vegas->cntRTT++;
+}
+
+/*
+ * 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.
+ */
+static void tcp_vegas_cwnd_event(struct sock *sk, enum tcp_ca_event event)
+{
+ if (event == CA_EVENT_CWND_RESTART ||
+ event == CA_EVENT_TX_START)
+ tcp_vegas_init(sk);
+}
+
+/* Extract info for Tcp socket info provided via netlink. */
+static void tcp_vegas_get_info(struct sock *sk, u32 ext,
+ struct sk_buff *skb)
+{
+ const struct vegas *ca = inet_csk_ca(sk);
+ if (ext & (1 << (INET_DIAG_VEGASINFO - 1))) {
+ struct tcpvegas_info *info;
+
+ info = RTA_DATA(__RTA_PUT(skb, INET_DIAG_VEGASINFO,
+ sizeof(*info)));
+
+ info->tcpv_enabled = ca->doing_vegas_now;
+ info->tcpv_rttcnt = ca->cntRTT;
+ info->tcpv_rtt = ca->baseRTT;
+ info->tcpv_minrtt = ca->minRTT;
+ rtattr_failure: ;
+ }
+}
+
+