diff options
Diffstat (limited to 'net/ipv4/tcp_yeah.h')
| -rw-r--r-- | net/ipv4/tcp_yeah.h | 134 |
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: ; + } +} + + |