993 lines
29 KiB
C
993 lines
29 KiB
C
/*
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* net/dccp/ccids/ccid3.c
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*
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* Copyright (c) 2007 The University of Aberdeen, Scotland, UK
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* Copyright (c) 2005-7 The University of Waikato, Hamilton, New Zealand.
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* Copyright (c) 2005-7 Ian McDonald <ian.mcdonald@jandi.co.nz>
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*
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* An implementation of the DCCP protocol
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*
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* This code has been developed by the University of Waikato WAND
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* research group. For further information please see http://www.wand.net.nz/
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*
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* This code also uses code from Lulea University, rereleased as GPL by its
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* authors:
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* Copyright (c) 2003 Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon
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*
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* Changes to meet Linux coding standards, to make it meet latest ccid3 draft
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* and to make it work as a loadable module in the DCCP stack written by
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* Arnaldo Carvalho de Melo <acme@conectiva.com.br>.
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*
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* Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include "../dccp.h"
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#include "ccid3.h"
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#include <asm/unaligned.h>
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#ifdef CONFIG_IP_DCCP_CCID3_DEBUG
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static int ccid3_debug;
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#define ccid3_pr_debug(format, a...) DCCP_PR_DEBUG(ccid3_debug, format, ##a)
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#else
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#define ccid3_pr_debug(format, a...)
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#endif
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/*
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* Transmitter Half-Connection Routines
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*/
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#ifdef CONFIG_IP_DCCP_CCID3_DEBUG
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static const char *ccid3_tx_state_name(enum ccid3_hc_tx_states state)
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{
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static char *ccid3_state_names[] = {
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[TFRC_SSTATE_NO_SENT] = "NO_SENT",
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[TFRC_SSTATE_NO_FBACK] = "NO_FBACK",
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[TFRC_SSTATE_FBACK] = "FBACK",
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[TFRC_SSTATE_TERM] = "TERM",
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};
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return ccid3_state_names[state];
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}
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#endif
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static void ccid3_hc_tx_set_state(struct sock *sk,
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enum ccid3_hc_tx_states state)
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{
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struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
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enum ccid3_hc_tx_states oldstate = hctx->ccid3hctx_state;
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ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
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dccp_role(sk), sk, ccid3_tx_state_name(oldstate),
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ccid3_tx_state_name(state));
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WARN_ON(state == oldstate);
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hctx->ccid3hctx_state = state;
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}
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/*
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* Compute the initial sending rate X_init in the manner of RFC 3390:
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*
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* X_init = min(4 * s, max(2 * s, 4380 bytes)) / RTT
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*
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* Note that RFC 3390 uses MSS, RFC 4342 refers to RFC 3390, and rfc3448bis
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* (rev-02) clarifies the use of RFC 3390 with regard to the above formula.
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* For consistency with other parts of the code, X_init is scaled by 2^6.
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*/
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static inline u64 rfc3390_initial_rate(struct sock *sk)
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{
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const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
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const __u32 w_init = min_t(__u32, 4 * hctx->ccid3hctx_s,
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max_t(__u32, 2 * hctx->ccid3hctx_s, 4380));
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return scaled_div(w_init << 6, hctx->ccid3hctx_rtt);
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}
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/*
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* Recalculate t_ipi and delta (should be called whenever X changes)
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*/
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static inline void ccid3_update_send_interval(struct ccid3_hc_tx_sock *hctx)
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{
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/* Calculate new t_ipi = s / X_inst (X_inst is in 64 * bytes/second) */
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hctx->ccid3hctx_t_ipi = scaled_div32(((u64)hctx->ccid3hctx_s) << 6,
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hctx->ccid3hctx_x);
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/* Calculate new delta by delta = min(t_ipi / 2, t_gran / 2) */
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hctx->ccid3hctx_delta = min_t(u32, hctx->ccid3hctx_t_ipi / 2,
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TFRC_OPSYS_HALF_TIME_GRAN);
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ccid3_pr_debug("t_ipi=%u, delta=%u, s=%u, X=%u\n",
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hctx->ccid3hctx_t_ipi, hctx->ccid3hctx_delta,
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hctx->ccid3hctx_s, (unsigned)(hctx->ccid3hctx_x >> 6));
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}
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static u32 ccid3_hc_tx_idle_rtt(struct ccid3_hc_tx_sock *hctx, ktime_t now)
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{
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u32 delta = ktime_us_delta(now, hctx->ccid3hctx_t_last_win_count);
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return delta / hctx->ccid3hctx_rtt;
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}
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/**
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* ccid3_hc_tx_update_x - Update allowed sending rate X
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* @stamp: most recent time if available - can be left NULL.
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* This function tracks draft rfc3448bis, check there for latest details.
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*
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* Note: X and X_recv are both stored in units of 64 * bytes/second, to support
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* fine-grained resolution of sending rates. This requires scaling by 2^6
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* throughout the code. Only X_calc is unscaled (in bytes/second).
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*
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*/
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static void ccid3_hc_tx_update_x(struct sock *sk, ktime_t *stamp)
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{
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struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
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__u64 min_rate = 2 * hctx->ccid3hctx_x_recv;
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const __u64 old_x = hctx->ccid3hctx_x;
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ktime_t now = stamp? *stamp : ktime_get_real();
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/*
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* Handle IDLE periods: do not reduce below RFC3390 initial sending rate
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* when idling [RFC 4342, 5.1]. Definition of idling is from rfc3448bis:
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* a sender is idle if it has not sent anything over a 2-RTT-period.
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* For consistency with X and X_recv, min_rate is also scaled by 2^6.
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*/
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if (ccid3_hc_tx_idle_rtt(hctx, now) >= 2) {
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min_rate = rfc3390_initial_rate(sk);
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min_rate = max(min_rate, 2 * hctx->ccid3hctx_x_recv);
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}
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if (hctx->ccid3hctx_p > 0) {
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hctx->ccid3hctx_x = min(((__u64)hctx->ccid3hctx_x_calc) << 6,
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min_rate);
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hctx->ccid3hctx_x = max(hctx->ccid3hctx_x,
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(((__u64)hctx->ccid3hctx_s) << 6) /
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TFRC_T_MBI);
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} else if (ktime_us_delta(now, hctx->ccid3hctx_t_ld)
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- (s64)hctx->ccid3hctx_rtt >= 0) {
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hctx->ccid3hctx_x =
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max(min(2 * hctx->ccid3hctx_x, min_rate),
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scaled_div(((__u64)hctx->ccid3hctx_s) << 6,
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hctx->ccid3hctx_rtt));
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hctx->ccid3hctx_t_ld = now;
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}
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if (hctx->ccid3hctx_x != old_x) {
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ccid3_pr_debug("X_prev=%u, X_now=%u, X_calc=%u, "
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"X_recv=%u\n", (unsigned)(old_x >> 6),
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(unsigned)(hctx->ccid3hctx_x >> 6),
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hctx->ccid3hctx_x_calc,
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(unsigned)(hctx->ccid3hctx_x_recv >> 6));
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ccid3_update_send_interval(hctx);
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}
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}
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/*
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* Track the mean packet size `s' (cf. RFC 4342, 5.3 and RFC 3448, 4.1)
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* @len: DCCP packet payload size in bytes
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*/
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static inline void ccid3_hc_tx_update_s(struct ccid3_hc_tx_sock *hctx, int len)
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{
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const u16 old_s = hctx->ccid3hctx_s;
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hctx->ccid3hctx_s = tfrc_ewma(hctx->ccid3hctx_s, len, 9);
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if (hctx->ccid3hctx_s != old_s)
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ccid3_update_send_interval(hctx);
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}
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/*
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* Update Window Counter using the algorithm from [RFC 4342, 8.1].
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* The algorithm is not applicable if RTT < 4 microseconds.
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*/
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static inline void ccid3_hc_tx_update_win_count(struct ccid3_hc_tx_sock *hctx,
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ktime_t now)
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{
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u32 quarter_rtts;
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if (unlikely(hctx->ccid3hctx_rtt < 4)) /* avoid divide-by-zero */
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return;
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quarter_rtts = ktime_us_delta(now, hctx->ccid3hctx_t_last_win_count);
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quarter_rtts /= hctx->ccid3hctx_rtt / 4;
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if (quarter_rtts > 0) {
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hctx->ccid3hctx_t_last_win_count = now;
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hctx->ccid3hctx_last_win_count += min_t(u32, quarter_rtts, 5);
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hctx->ccid3hctx_last_win_count &= 0xF; /* mod 16 */
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}
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}
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static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
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{
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struct sock *sk = (struct sock *)data;
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struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
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unsigned long t_nfb = USEC_PER_SEC / 5;
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bh_lock_sock(sk);
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if (sock_owned_by_user(sk)) {
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/* Try again later. */
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/* XXX: set some sensible MIB */
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goto restart_timer;
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}
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ccid3_pr_debug("%s(%p, state=%s) - entry \n", dccp_role(sk), sk,
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ccid3_tx_state_name(hctx->ccid3hctx_state));
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switch (hctx->ccid3hctx_state) {
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case TFRC_SSTATE_NO_FBACK:
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/* RFC 3448, 4.4: Halve send rate directly */
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hctx->ccid3hctx_x = max(hctx->ccid3hctx_x / 2,
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(((__u64)hctx->ccid3hctx_s) << 6) /
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TFRC_T_MBI);
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ccid3_pr_debug("%s(%p, state=%s), updated tx rate to %u "
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"bytes/s\n", dccp_role(sk), sk,
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ccid3_tx_state_name(hctx->ccid3hctx_state),
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(unsigned)(hctx->ccid3hctx_x >> 6));
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/* The value of R is still undefined and so we can not recompute
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* the timeout value. Keep initial value as per [RFC 4342, 5]. */
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t_nfb = TFRC_INITIAL_TIMEOUT;
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ccid3_update_send_interval(hctx);
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break;
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case TFRC_SSTATE_FBACK:
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/*
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* Modify the cached value of X_recv [RFC 3448, 4.4]
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*
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* If (p == 0 || X_calc > 2 * X_recv)
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* X_recv = max(X_recv / 2, s / (2 * t_mbi));
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* Else
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* X_recv = X_calc / 4;
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*
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* Note that X_recv is scaled by 2^6 while X_calc is not
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*/
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BUG_ON(hctx->ccid3hctx_p && !hctx->ccid3hctx_x_calc);
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if (hctx->ccid3hctx_p == 0 ||
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(hctx->ccid3hctx_x_calc > (hctx->ccid3hctx_x_recv >> 5))) {
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hctx->ccid3hctx_x_recv =
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max(hctx->ccid3hctx_x_recv / 2,
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(((__u64)hctx->ccid3hctx_s) << 6) /
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(2 * TFRC_T_MBI));
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} else {
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hctx->ccid3hctx_x_recv = hctx->ccid3hctx_x_calc;
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hctx->ccid3hctx_x_recv <<= 4;
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}
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/* Now recalculate X [RFC 3448, 4.3, step (4)] */
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ccid3_hc_tx_update_x(sk, NULL);
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/*
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* Schedule no feedback timer to expire in
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* max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi)
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* See comments in packet_recv() regarding the value of t_RTO.
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*/
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t_nfb = max(hctx->ccid3hctx_t_rto, 2 * hctx->ccid3hctx_t_ipi);
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break;
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case TFRC_SSTATE_NO_SENT:
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DCCP_BUG("%s(%p) - Illegal state NO_SENT", dccp_role(sk), sk);
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/* fall through */
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case TFRC_SSTATE_TERM:
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goto out;
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}
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restart_timer:
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sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
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jiffies + usecs_to_jiffies(t_nfb));
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out:
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bh_unlock_sock(sk);
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sock_put(sk);
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}
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/*
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* returns
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* > 0: delay (in msecs) that should pass before actually sending
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* = 0: can send immediately
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* < 0: error condition; do not send packet
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*/
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static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
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{
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struct dccp_sock *dp = dccp_sk(sk);
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struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
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ktime_t now = ktime_get_real();
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s64 delay;
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/*
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* This function is called only for Data and DataAck packets. Sending
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* zero-sized Data(Ack)s is theoretically possible, but for congestion
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* control this case is pathological - ignore it.
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*/
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if (unlikely(skb->len == 0))
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return -EBADMSG;
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switch (hctx->ccid3hctx_state) {
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case TFRC_SSTATE_NO_SENT:
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sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
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(jiffies +
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usecs_to_jiffies(TFRC_INITIAL_TIMEOUT)));
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hctx->ccid3hctx_last_win_count = 0;
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hctx->ccid3hctx_t_last_win_count = now;
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/* Set t_0 for initial packet */
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hctx->ccid3hctx_t_nom = now;
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hctx->ccid3hctx_s = skb->len;
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/*
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* Use initial RTT sample when available: recommended by erratum
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* to RFC 4342. This implements the initialisation procedure of
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* draft rfc3448bis, section 4.2. Remember, X is scaled by 2^6.
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*/
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if (dp->dccps_syn_rtt) {
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ccid3_pr_debug("SYN RTT = %uus\n", dp->dccps_syn_rtt);
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hctx->ccid3hctx_rtt = dp->dccps_syn_rtt;
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hctx->ccid3hctx_x = rfc3390_initial_rate(sk);
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hctx->ccid3hctx_t_ld = now;
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} else {
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/* Sender does not have RTT sample: X_pps = 1 pkt/sec */
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hctx->ccid3hctx_x = hctx->ccid3hctx_s;
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hctx->ccid3hctx_x <<= 6;
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}
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ccid3_update_send_interval(hctx);
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ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
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break;
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case TFRC_SSTATE_NO_FBACK:
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case TFRC_SSTATE_FBACK:
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delay = ktime_us_delta(hctx->ccid3hctx_t_nom, now);
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ccid3_pr_debug("delay=%ld\n", (long)delay);
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/*
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* Scheduling of packet transmissions [RFC 3448, 4.6]
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*
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* if (t_now > t_nom - delta)
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* // send the packet now
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* else
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* // send the packet in (t_nom - t_now) milliseconds.
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*/
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if (delay - (s64)hctx->ccid3hctx_delta >= 1000)
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return (u32)delay / 1000L;
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ccid3_hc_tx_update_win_count(hctx, now);
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break;
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case TFRC_SSTATE_TERM:
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DCCP_BUG("%s(%p) - Illegal state TERM", dccp_role(sk), sk);
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return -EINVAL;
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}
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/* prepare to send now (add options etc.) */
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dp->dccps_hc_tx_insert_options = 1;
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DCCP_SKB_CB(skb)->dccpd_ccval = hctx->ccid3hctx_last_win_count;
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/* set the nominal send time for the next following packet */
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hctx->ccid3hctx_t_nom = ktime_add_us(hctx->ccid3hctx_t_nom,
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hctx->ccid3hctx_t_ipi);
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return 0;
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}
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static void ccid3_hc_tx_packet_sent(struct sock *sk, int more,
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unsigned int len)
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{
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struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
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ccid3_hc_tx_update_s(hctx, len);
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if (tfrc_tx_hist_add(&hctx->ccid3hctx_hist, dccp_sk(sk)->dccps_gss))
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DCCP_CRIT("packet history - out of memory!");
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}
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static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
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{
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struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
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struct ccid3_options_received *opt_recv;
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ktime_t now;
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unsigned long t_nfb;
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u32 pinv, r_sample;
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/* we are only interested in ACKs */
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if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK ||
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DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_DATAACK))
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return;
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opt_recv = &hctx->ccid3hctx_options_received;
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switch (hctx->ccid3hctx_state) {
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case TFRC_SSTATE_NO_FBACK:
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case TFRC_SSTATE_FBACK:
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now = ktime_get_real();
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/* estimate RTT from history if ACK number is valid */
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r_sample = tfrc_tx_hist_rtt(hctx->ccid3hctx_hist,
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DCCP_SKB_CB(skb)->dccpd_ack_seq, now);
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if (r_sample == 0) {
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DCCP_WARN("%s(%p): %s with bogus ACK-%llu\n", dccp_role(sk), sk,
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dccp_packet_name(DCCP_SKB_CB(skb)->dccpd_type),
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|
(unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq);
|
|
return;
|
|
}
|
|
|
|
/* Update receive rate in units of 64 * bytes/second */
|
|
hctx->ccid3hctx_x_recv = opt_recv->ccid3or_receive_rate;
|
|
hctx->ccid3hctx_x_recv <<= 6;
|
|
|
|
/* Update loss event rate */
|
|
pinv = opt_recv->ccid3or_loss_event_rate;
|
|
if (pinv == ~0U || pinv == 0) /* see RFC 4342, 8.5 */
|
|
hctx->ccid3hctx_p = 0;
|
|
else /* can not exceed 100% */
|
|
hctx->ccid3hctx_p = 1000000 / pinv;
|
|
/*
|
|
* Validate new RTT sample and update moving average
|
|
*/
|
|
r_sample = dccp_sample_rtt(sk, r_sample);
|
|
hctx->ccid3hctx_rtt = tfrc_ewma(hctx->ccid3hctx_rtt, r_sample, 9);
|
|
|
|
if (hctx->ccid3hctx_state == TFRC_SSTATE_NO_FBACK) {
|
|
/*
|
|
* Larger Initial Windows [RFC 4342, sec. 5]
|
|
*/
|
|
hctx->ccid3hctx_x = rfc3390_initial_rate(sk);
|
|
hctx->ccid3hctx_t_ld = now;
|
|
|
|
ccid3_update_send_interval(hctx);
|
|
|
|
ccid3_pr_debug("%s(%p), s=%u, MSS=%u, "
|
|
"R_sample=%uus, X=%u\n", dccp_role(sk),
|
|
sk, hctx->ccid3hctx_s,
|
|
dccp_sk(sk)->dccps_mss_cache, r_sample,
|
|
(unsigned)(hctx->ccid3hctx_x >> 6));
|
|
|
|
ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK);
|
|
} else {
|
|
|
|
/* Update sending rate (step 4 of [RFC 3448, 4.3]) */
|
|
if (hctx->ccid3hctx_p > 0)
|
|
hctx->ccid3hctx_x_calc =
|
|
tfrc_calc_x(hctx->ccid3hctx_s,
|
|
hctx->ccid3hctx_rtt,
|
|
hctx->ccid3hctx_p);
|
|
ccid3_hc_tx_update_x(sk, &now);
|
|
|
|
ccid3_pr_debug("%s(%p), RTT=%uus (sample=%uus), s=%u, "
|
|
"p=%u, X_calc=%u, X_recv=%u, X=%u\n",
|
|
dccp_role(sk),
|
|
sk, hctx->ccid3hctx_rtt, r_sample,
|
|
hctx->ccid3hctx_s, hctx->ccid3hctx_p,
|
|
hctx->ccid3hctx_x_calc,
|
|
(unsigned)(hctx->ccid3hctx_x_recv >> 6),
|
|
(unsigned)(hctx->ccid3hctx_x >> 6));
|
|
}
|
|
|
|
/* unschedule no feedback timer */
|
|
sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
|
|
|
|
/*
|
|
* As we have calculated new ipi, delta, t_nom it is possible
|
|
* that we now can send a packet, so wake up dccp_wait_for_ccid
|
|
*/
|
|
sk->sk_write_space(sk);
|
|
|
|
/*
|
|
* Update timeout interval for the nofeedback timer.
|
|
* We use a configuration option to increase the lower bound.
|
|
* This can help avoid triggering the nofeedback timer too
|
|
* often ('spinning') on LANs with small RTTs.
|
|
*/
|
|
hctx->ccid3hctx_t_rto = max_t(u32, 4 * hctx->ccid3hctx_rtt,
|
|
CONFIG_IP_DCCP_CCID3_RTO *
|
|
(USEC_PER_SEC/1000));
|
|
/*
|
|
* Schedule no feedback timer to expire in
|
|
* max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi)
|
|
*/
|
|
t_nfb = max(hctx->ccid3hctx_t_rto, 2 * hctx->ccid3hctx_t_ipi);
|
|
|
|
ccid3_pr_debug("%s(%p), Scheduled no feedback timer to "
|
|
"expire in %lu jiffies (%luus)\n",
|
|
dccp_role(sk),
|
|
sk, usecs_to_jiffies(t_nfb), t_nfb);
|
|
|
|
sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
|
|
jiffies + usecs_to_jiffies(t_nfb));
|
|
break;
|
|
case TFRC_SSTATE_NO_SENT: /* fall through */
|
|
case TFRC_SSTATE_TERM: /* ignore feedback when closing */
|
|
break;
|
|
}
|
|
}
|
|
|
|
static int ccid3_hc_tx_parse_options(struct sock *sk, unsigned char option,
|
|
unsigned char len, u16 idx,
|
|
unsigned char *value)
|
|
{
|
|
int rc = 0;
|
|
const struct dccp_sock *dp = dccp_sk(sk);
|
|
struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
|
|
struct ccid3_options_received *opt_recv;
|
|
__be32 opt_val;
|
|
|
|
opt_recv = &hctx->ccid3hctx_options_received;
|
|
|
|
if (opt_recv->ccid3or_seqno != dp->dccps_gsr) {
|
|
opt_recv->ccid3or_seqno = dp->dccps_gsr;
|
|
opt_recv->ccid3or_loss_event_rate = ~0;
|
|
opt_recv->ccid3or_loss_intervals_idx = 0;
|
|
opt_recv->ccid3or_loss_intervals_len = 0;
|
|
opt_recv->ccid3or_receive_rate = 0;
|
|
}
|
|
|
|
switch (option) {
|
|
case TFRC_OPT_LOSS_EVENT_RATE:
|
|
if (unlikely(len != 4)) {
|
|
DCCP_WARN("%s(%p), invalid len %d "
|
|
"for TFRC_OPT_LOSS_EVENT_RATE\n",
|
|
dccp_role(sk), sk, len);
|
|
rc = -EINVAL;
|
|
} else {
|
|
opt_val = get_unaligned((__be32 *)value);
|
|
opt_recv->ccid3or_loss_event_rate = ntohl(opt_val);
|
|
ccid3_pr_debug("%s(%p), LOSS_EVENT_RATE=%u\n",
|
|
dccp_role(sk), sk,
|
|
opt_recv->ccid3or_loss_event_rate);
|
|
}
|
|
break;
|
|
case TFRC_OPT_LOSS_INTERVALS:
|
|
opt_recv->ccid3or_loss_intervals_idx = idx;
|
|
opt_recv->ccid3or_loss_intervals_len = len;
|
|
ccid3_pr_debug("%s(%p), LOSS_INTERVALS=(%u, %u)\n",
|
|
dccp_role(sk), sk,
|
|
opt_recv->ccid3or_loss_intervals_idx,
|
|
opt_recv->ccid3or_loss_intervals_len);
|
|
break;
|
|
case TFRC_OPT_RECEIVE_RATE:
|
|
if (unlikely(len != 4)) {
|
|
DCCP_WARN("%s(%p), invalid len %d "
|
|
"for TFRC_OPT_RECEIVE_RATE\n",
|
|
dccp_role(sk), sk, len);
|
|
rc = -EINVAL;
|
|
} else {
|
|
opt_val = get_unaligned((__be32 *)value);
|
|
opt_recv->ccid3or_receive_rate = ntohl(opt_val);
|
|
ccid3_pr_debug("%s(%p), RECEIVE_RATE=%u\n",
|
|
dccp_role(sk), sk,
|
|
opt_recv->ccid3or_receive_rate);
|
|
}
|
|
break;
|
|
}
|
|
|
|
return rc;
|
|
}
|
|
|
|
static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk)
|
|
{
|
|
struct ccid3_hc_tx_sock *hctx = ccid_priv(ccid);
|
|
|
|
hctx->ccid3hctx_state = TFRC_SSTATE_NO_SENT;
|
|
hctx->ccid3hctx_hist = NULL;
|
|
setup_timer(&hctx->ccid3hctx_no_feedback_timer,
|
|
ccid3_hc_tx_no_feedback_timer, (unsigned long)sk);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void ccid3_hc_tx_exit(struct sock *sk)
|
|
{
|
|
struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
|
|
|
|
ccid3_hc_tx_set_state(sk, TFRC_SSTATE_TERM);
|
|
sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
|
|
|
|
tfrc_tx_hist_purge(&hctx->ccid3hctx_hist);
|
|
}
|
|
|
|
static void ccid3_hc_tx_get_info(struct sock *sk, struct tcp_info *info)
|
|
{
|
|
struct ccid3_hc_tx_sock *hctx;
|
|
|
|
/* Listen socks doesn't have a private CCID block */
|
|
if (sk->sk_state == DCCP_LISTEN)
|
|
return;
|
|
|
|
hctx = ccid3_hc_tx_sk(sk);
|
|
info->tcpi_rto = hctx->ccid3hctx_t_rto;
|
|
info->tcpi_rtt = hctx->ccid3hctx_rtt;
|
|
}
|
|
|
|
static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len,
|
|
u32 __user *optval, int __user *optlen)
|
|
{
|
|
const struct ccid3_hc_tx_sock *hctx;
|
|
const void *val;
|
|
|
|
/* Listen socks doesn't have a private CCID block */
|
|
if (sk->sk_state == DCCP_LISTEN)
|
|
return -EINVAL;
|
|
|
|
hctx = ccid3_hc_tx_sk(sk);
|
|
switch (optname) {
|
|
case DCCP_SOCKOPT_CCID_TX_INFO:
|
|
if (len < sizeof(hctx->ccid3hctx_tfrc))
|
|
return -EINVAL;
|
|
len = sizeof(hctx->ccid3hctx_tfrc);
|
|
val = &hctx->ccid3hctx_tfrc;
|
|
break;
|
|
default:
|
|
return -ENOPROTOOPT;
|
|
}
|
|
|
|
if (put_user(len, optlen) || copy_to_user(optval, val, len))
|
|
return -EFAULT;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Receiver Half-Connection Routines
|
|
*/
|
|
|
|
/* CCID3 feedback types */
|
|
enum ccid3_fback_type {
|
|
CCID3_FBACK_NONE = 0,
|
|
CCID3_FBACK_INITIAL,
|
|
CCID3_FBACK_PERIODIC,
|
|
CCID3_FBACK_PARAM_CHANGE
|
|
};
|
|
|
|
#ifdef CONFIG_IP_DCCP_CCID3_DEBUG
|
|
static const char *ccid3_rx_state_name(enum ccid3_hc_rx_states state)
|
|
{
|
|
static char *ccid3_rx_state_names[] = {
|
|
[TFRC_RSTATE_NO_DATA] = "NO_DATA",
|
|
[TFRC_RSTATE_DATA] = "DATA",
|
|
[TFRC_RSTATE_TERM] = "TERM",
|
|
};
|
|
|
|
return ccid3_rx_state_names[state];
|
|
}
|
|
#endif
|
|
|
|
static void ccid3_hc_rx_set_state(struct sock *sk,
|
|
enum ccid3_hc_rx_states state)
|
|
{
|
|
struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
|
|
enum ccid3_hc_rx_states oldstate = hcrx->ccid3hcrx_state;
|
|
|
|
ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
|
|
dccp_role(sk), sk, ccid3_rx_state_name(oldstate),
|
|
ccid3_rx_state_name(state));
|
|
WARN_ON(state == oldstate);
|
|
hcrx->ccid3hcrx_state = state;
|
|
}
|
|
|
|
static void ccid3_hc_rx_send_feedback(struct sock *sk,
|
|
const struct sk_buff *skb,
|
|
enum ccid3_fback_type fbtype)
|
|
{
|
|
struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
|
|
struct dccp_sock *dp = dccp_sk(sk);
|
|
ktime_t now;
|
|
s64 delta = 0;
|
|
|
|
if (unlikely(hcrx->ccid3hcrx_state == TFRC_RSTATE_TERM))
|
|
return;
|
|
|
|
now = ktime_get_real();
|
|
|
|
switch (fbtype) {
|
|
case CCID3_FBACK_INITIAL:
|
|
hcrx->ccid3hcrx_x_recv = 0;
|
|
hcrx->ccid3hcrx_pinv = ~0U; /* see RFC 4342, 8.5 */
|
|
break;
|
|
case CCID3_FBACK_PARAM_CHANGE:
|
|
/*
|
|
* When parameters change (new loss or p > p_prev), we do not
|
|
* have a reliable estimate for R_m of [RFC 3448, 6.2] and so
|
|
* need to reuse the previous value of X_recv. However, when
|
|
* X_recv was 0 (due to early loss), this would kill X down to
|
|
* s/t_mbi (i.e. one packet in 64 seconds).
|
|
* To avoid such drastic reduction, we approximate X_recv as
|
|
* the number of bytes since last feedback.
|
|
* This is a safe fallback, since X is bounded above by X_calc.
|
|
*/
|
|
if (hcrx->ccid3hcrx_x_recv > 0)
|
|
break;
|
|
/* fall through */
|
|
case CCID3_FBACK_PERIODIC:
|
|
delta = ktime_us_delta(now, hcrx->ccid3hcrx_tstamp_last_feedback);
|
|
if (delta <= 0)
|
|
DCCP_BUG("delta (%ld) <= 0", (long)delta);
|
|
else
|
|
hcrx->ccid3hcrx_x_recv =
|
|
scaled_div32(hcrx->ccid3hcrx_bytes_recv, delta);
|
|
break;
|
|
default:
|
|
return;
|
|
}
|
|
|
|
ccid3_pr_debug("Interval %ldusec, X_recv=%u, 1/p=%u\n", (long)delta,
|
|
hcrx->ccid3hcrx_x_recv, hcrx->ccid3hcrx_pinv);
|
|
|
|
hcrx->ccid3hcrx_tstamp_last_feedback = now;
|
|
hcrx->ccid3hcrx_last_counter = dccp_hdr(skb)->dccph_ccval;
|
|
hcrx->ccid3hcrx_bytes_recv = 0;
|
|
|
|
dp->dccps_hc_rx_insert_options = 1;
|
|
dccp_send_ack(sk);
|
|
}
|
|
|
|
static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb)
|
|
{
|
|
const struct ccid3_hc_rx_sock *hcrx;
|
|
__be32 x_recv, pinv;
|
|
|
|
if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN))
|
|
return 0;
|
|
|
|
hcrx = ccid3_hc_rx_sk(sk);
|
|
|
|
if (dccp_packet_without_ack(skb))
|
|
return 0;
|
|
|
|
x_recv = htonl(hcrx->ccid3hcrx_x_recv);
|
|
pinv = htonl(hcrx->ccid3hcrx_pinv);
|
|
|
|
if (dccp_insert_option(sk, skb, TFRC_OPT_LOSS_EVENT_RATE,
|
|
&pinv, sizeof(pinv)) ||
|
|
dccp_insert_option(sk, skb, TFRC_OPT_RECEIVE_RATE,
|
|
&x_recv, sizeof(x_recv)))
|
|
return -1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/** ccid3_first_li - Implements [RFC 3448, 6.3.1]
|
|
*
|
|
* Determine the length of the first loss interval via inverse lookup.
|
|
* Assume that X_recv can be computed by the throughput equation
|
|
* s
|
|
* X_recv = --------
|
|
* R * fval
|
|
* Find some p such that f(p) = fval; return 1/p (scaled).
|
|
*/
|
|
static u32 ccid3_first_li(struct sock *sk)
|
|
{
|
|
struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
|
|
u32 x_recv, p, delta;
|
|
u64 fval;
|
|
|
|
if (hcrx->ccid3hcrx_rtt == 0) {
|
|
DCCP_WARN("No RTT estimate available, using fallback RTT\n");
|
|
hcrx->ccid3hcrx_rtt = DCCP_FALLBACK_RTT;
|
|
}
|
|
|
|
delta = ktime_to_us(net_timedelta(hcrx->ccid3hcrx_tstamp_last_feedback));
|
|
x_recv = scaled_div32(hcrx->ccid3hcrx_bytes_recv, delta);
|
|
if (x_recv == 0) { /* would also trigger divide-by-zero */
|
|
DCCP_WARN("X_recv==0\n");
|
|
if ((x_recv = hcrx->ccid3hcrx_x_recv) == 0) {
|
|
DCCP_BUG("stored value of X_recv is zero");
|
|
return ~0U;
|
|
}
|
|
}
|
|
|
|
fval = scaled_div(hcrx->ccid3hcrx_s, hcrx->ccid3hcrx_rtt);
|
|
fval = scaled_div32(fval, x_recv);
|
|
p = tfrc_calc_x_reverse_lookup(fval);
|
|
|
|
ccid3_pr_debug("%s(%p), receive rate=%u bytes/s, implied "
|
|
"loss rate=%u\n", dccp_role(sk), sk, x_recv, p);
|
|
|
|
return p == 0 ? ~0U : scaled_div(1, p);
|
|
}
|
|
|
|
static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
|
|
{
|
|
struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
|
|
enum ccid3_fback_type do_feedback = CCID3_FBACK_NONE;
|
|
const u32 ndp = dccp_sk(sk)->dccps_options_received.dccpor_ndp;
|
|
const bool is_data_packet = dccp_data_packet(skb);
|
|
|
|
if (unlikely(hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)) {
|
|
if (is_data_packet) {
|
|
const u32 payload = skb->len - dccp_hdr(skb)->dccph_doff * 4;
|
|
do_feedback = CCID3_FBACK_INITIAL;
|
|
ccid3_hc_rx_set_state(sk, TFRC_RSTATE_DATA);
|
|
hcrx->ccid3hcrx_s = payload;
|
|
/*
|
|
* Not necessary to update ccid3hcrx_bytes_recv here,
|
|
* since X_recv = 0 for the first feedback packet (cf.
|
|
* RFC 3448, 6.3) -- gerrit
|
|
*/
|
|
}
|
|
goto update_records;
|
|
}
|
|
|
|
if (tfrc_rx_hist_duplicate(&hcrx->ccid3hcrx_hist, skb))
|
|
return; /* done receiving */
|
|
|
|
if (is_data_packet) {
|
|
const u32 payload = skb->len - dccp_hdr(skb)->dccph_doff * 4;
|
|
/*
|
|
* Update moving-average of s and the sum of received payload bytes
|
|
*/
|
|
hcrx->ccid3hcrx_s = tfrc_ewma(hcrx->ccid3hcrx_s, payload, 9);
|
|
hcrx->ccid3hcrx_bytes_recv += payload;
|
|
}
|
|
|
|
/*
|
|
* Handle pending losses and otherwise check for new loss
|
|
*/
|
|
if (tfrc_rx_hist_loss_pending(&hcrx->ccid3hcrx_hist) &&
|
|
tfrc_rx_handle_loss(&hcrx->ccid3hcrx_hist,
|
|
&hcrx->ccid3hcrx_li_hist,
|
|
skb, ndp, ccid3_first_li, sk) ) {
|
|
do_feedback = CCID3_FBACK_PARAM_CHANGE;
|
|
goto done_receiving;
|
|
}
|
|
|
|
if (tfrc_rx_hist_new_loss_indicated(&hcrx->ccid3hcrx_hist, skb, ndp))
|
|
goto update_records;
|
|
|
|
/*
|
|
* Handle data packets: RTT sampling and monitoring p
|
|
*/
|
|
if (unlikely(!is_data_packet))
|
|
goto update_records;
|
|
|
|
if (!tfrc_lh_is_initialised(&hcrx->ccid3hcrx_li_hist)) {
|
|
const u32 sample = tfrc_rx_hist_sample_rtt(&hcrx->ccid3hcrx_hist, skb);
|
|
/*
|
|
* Empty loss history: no loss so far, hence p stays 0.
|
|
* Sample RTT values, since an RTT estimate is required for the
|
|
* computation of p when the first loss occurs; RFC 3448, 6.3.1.
|
|
*/
|
|
if (sample != 0)
|
|
hcrx->ccid3hcrx_rtt = tfrc_ewma(hcrx->ccid3hcrx_rtt, sample, 9);
|
|
|
|
} else if (tfrc_lh_update_i_mean(&hcrx->ccid3hcrx_li_hist, skb)) {
|
|
/*
|
|
* Step (3) of [RFC 3448, 6.1]: Recompute I_mean and, if I_mean
|
|
* has decreased (resp. p has increased), send feedback now.
|
|
*/
|
|
do_feedback = CCID3_FBACK_PARAM_CHANGE;
|
|
}
|
|
|
|
/*
|
|
* Check if the periodic once-per-RTT feedback is due; RFC 4342, 10.3
|
|
*/
|
|
if (SUB16(dccp_hdr(skb)->dccph_ccval, hcrx->ccid3hcrx_last_counter) > 3)
|
|
do_feedback = CCID3_FBACK_PERIODIC;
|
|
|
|
update_records:
|
|
tfrc_rx_hist_add_packet(&hcrx->ccid3hcrx_hist, skb, ndp);
|
|
|
|
done_receiving:
|
|
if (do_feedback)
|
|
ccid3_hc_rx_send_feedback(sk, skb, do_feedback);
|
|
}
|
|
|
|
static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk)
|
|
{
|
|
struct ccid3_hc_rx_sock *hcrx = ccid_priv(ccid);
|
|
|
|
hcrx->ccid3hcrx_state = TFRC_RSTATE_NO_DATA;
|
|
tfrc_lh_init(&hcrx->ccid3hcrx_li_hist);
|
|
return tfrc_rx_hist_alloc(&hcrx->ccid3hcrx_hist);
|
|
}
|
|
|
|
static void ccid3_hc_rx_exit(struct sock *sk)
|
|
{
|
|
struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
|
|
|
|
ccid3_hc_rx_set_state(sk, TFRC_RSTATE_TERM);
|
|
|
|
tfrc_rx_hist_purge(&hcrx->ccid3hcrx_hist);
|
|
tfrc_lh_cleanup(&hcrx->ccid3hcrx_li_hist);
|
|
}
|
|
|
|
static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info)
|
|
{
|
|
const struct ccid3_hc_rx_sock *hcrx;
|
|
|
|
/* Listen socks doesn't have a private CCID block */
|
|
if (sk->sk_state == DCCP_LISTEN)
|
|
return;
|
|
|
|
hcrx = ccid3_hc_rx_sk(sk);
|
|
info->tcpi_ca_state = hcrx->ccid3hcrx_state;
|
|
info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
|
|
info->tcpi_rcv_rtt = hcrx->ccid3hcrx_rtt;
|
|
}
|
|
|
|
static int ccid3_hc_rx_getsockopt(struct sock *sk, const int optname, int len,
|
|
u32 __user *optval, int __user *optlen)
|
|
{
|
|
const struct ccid3_hc_rx_sock *hcrx;
|
|
struct tfrc_rx_info rx_info;
|
|
const void *val;
|
|
|
|
/* Listen socks doesn't have a private CCID block */
|
|
if (sk->sk_state == DCCP_LISTEN)
|
|
return -EINVAL;
|
|
|
|
hcrx = ccid3_hc_rx_sk(sk);
|
|
switch (optname) {
|
|
case DCCP_SOCKOPT_CCID_RX_INFO:
|
|
if (len < sizeof(rx_info))
|
|
return -EINVAL;
|
|
rx_info.tfrcrx_x_recv = hcrx->ccid3hcrx_x_recv;
|
|
rx_info.tfrcrx_rtt = hcrx->ccid3hcrx_rtt;
|
|
rx_info.tfrcrx_p = hcrx->ccid3hcrx_pinv == 0 ? ~0U :
|
|
scaled_div(1, hcrx->ccid3hcrx_pinv);
|
|
len = sizeof(rx_info);
|
|
val = &rx_info;
|
|
break;
|
|
default:
|
|
return -ENOPROTOOPT;
|
|
}
|
|
|
|
if (put_user(len, optlen) || copy_to_user(optval, val, len))
|
|
return -EFAULT;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct ccid_operations ccid3 = {
|
|
.ccid_id = DCCPC_CCID3,
|
|
.ccid_name = "TCP-Friendly Rate Control",
|
|
.ccid_owner = THIS_MODULE,
|
|
.ccid_hc_tx_obj_size = sizeof(struct ccid3_hc_tx_sock),
|
|
.ccid_hc_tx_init = ccid3_hc_tx_init,
|
|
.ccid_hc_tx_exit = ccid3_hc_tx_exit,
|
|
.ccid_hc_tx_send_packet = ccid3_hc_tx_send_packet,
|
|
.ccid_hc_tx_packet_sent = ccid3_hc_tx_packet_sent,
|
|
.ccid_hc_tx_packet_recv = ccid3_hc_tx_packet_recv,
|
|
.ccid_hc_tx_parse_options = ccid3_hc_tx_parse_options,
|
|
.ccid_hc_rx_obj_size = sizeof(struct ccid3_hc_rx_sock),
|
|
.ccid_hc_rx_init = ccid3_hc_rx_init,
|
|
.ccid_hc_rx_exit = ccid3_hc_rx_exit,
|
|
.ccid_hc_rx_insert_options = ccid3_hc_rx_insert_options,
|
|
.ccid_hc_rx_packet_recv = ccid3_hc_rx_packet_recv,
|
|
.ccid_hc_rx_get_info = ccid3_hc_rx_get_info,
|
|
.ccid_hc_tx_get_info = ccid3_hc_tx_get_info,
|
|
.ccid_hc_rx_getsockopt = ccid3_hc_rx_getsockopt,
|
|
.ccid_hc_tx_getsockopt = ccid3_hc_tx_getsockopt,
|
|
};
|
|
|
|
#ifdef CONFIG_IP_DCCP_CCID3_DEBUG
|
|
module_param(ccid3_debug, bool, 0444);
|
|
MODULE_PARM_DESC(ccid3_debug, "Enable debug messages");
|
|
#endif
|
|
|
|
static __init int ccid3_module_init(void)
|
|
{
|
|
return ccid_register(&ccid3);
|
|
}
|
|
module_init(ccid3_module_init);
|
|
|
|
static __exit void ccid3_module_exit(void)
|
|
{
|
|
ccid_unregister(&ccid3);
|
|
}
|
|
module_exit(ccid3_module_exit);
|
|
|
|
MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>, "
|
|
"Arnaldo Carvalho de Melo <acme@ghostprotocols.net>");
|
|
MODULE_DESCRIPTION("DCCP TFRC CCID3 CCID");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_ALIAS("net-dccp-ccid-3");
|