136 строки
3.7 KiB
C
136 строки
3.7 KiB
C
#include <linux/mm.h>
|
|
#include <linux/module.h>
|
|
#include <linux/skbuff.h>
|
|
#include <linux/inet_diag.h>
|
|
#include <asm/div64.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: ;
|
|
}
|
|
}
|
|
|
|
|