17931287dSThomas Gleixner // SPDX-License-Identifier: GPL-2.0-or-later
27c657876SArnaldo Carvalho de Melo /*
3954c2db8SGerrit Renker * Copyright (c) 2007 The University of Aberdeen, Scotland, UK
4b2f41ff4SIan McDonald * Copyright (c) 2005-7 The University of Waikato, Hamilton, New Zealand.
5b2f41ff4SIan McDonald * Copyright (c) 2005-7 Ian McDonald <ian.mcdonald@jandi.co.nz>
67c657876SArnaldo Carvalho de Melo *
77c657876SArnaldo Carvalho de Melo * An implementation of the DCCP protocol
87c657876SArnaldo Carvalho de Melo *
97c657876SArnaldo Carvalho de Melo * This code has been developed by the University of Waikato WAND
10266f3128SAlexander A. Klimov * research group. For further information please see https://www.wand.net.nz/
117c657876SArnaldo Carvalho de Melo *
127c657876SArnaldo Carvalho de Melo * This code also uses code from Lulea University, rereleased as GPL by its
137c657876SArnaldo Carvalho de Melo * authors:
147c657876SArnaldo Carvalho de Melo * Copyright (c) 2003 Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon
157c657876SArnaldo Carvalho de Melo *
167c657876SArnaldo Carvalho de Melo * Changes to meet Linux coding standards, to make it meet latest ccid3 draft
177c657876SArnaldo Carvalho de Melo * and to make it work as a loadable module in the DCCP stack written by
187c657876SArnaldo Carvalho de Melo * Arnaldo Carvalho de Melo <acme@conectiva.com.br>.
197c657876SArnaldo Carvalho de Melo *
207c657876SArnaldo Carvalho de Melo * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
217c657876SArnaldo Carvalho de Melo */
227c657876SArnaldo Carvalho de Melo #include "../dccp.h"
237c657876SArnaldo Carvalho de Melo #include "ccid3.h"
247c657876SArnaldo Carvalho de Melo
2576fd1e87SGerrit Renker #include <asm/unaligned.h>
2676fd1e87SGerrit Renker
2756724aa4SGerrit Renker #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
28eb939922SRusty Russell static bool ccid3_debug;
2956724aa4SGerrit Renker #define ccid3_pr_debug(format, a...) DCCP_PR_DEBUG(ccid3_debug, format, ##a)
307c657876SArnaldo Carvalho de Melo #else
317c657876SArnaldo Carvalho de Melo #define ccid3_pr_debug(format, a...)
327c657876SArnaldo Carvalho de Melo #endif
337c657876SArnaldo Carvalho de Melo
349bf17475SGerrit Renker /*
359bf17475SGerrit Renker * Transmitter Half-Connection Routines
369bf17475SGerrit Renker */
37410e27a4SGerrit Renker #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
ccid3_tx_state_name(enum ccid3_hc_tx_states state)38410e27a4SGerrit Renker static const char *ccid3_tx_state_name(enum ccid3_hc_tx_states state)
39410e27a4SGerrit Renker {
4036cbd3dcSJan Engelhardt static const char *const ccid3_state_names[] = {
41410e27a4SGerrit Renker [TFRC_SSTATE_NO_SENT] = "NO_SENT",
42410e27a4SGerrit Renker [TFRC_SSTATE_NO_FBACK] = "NO_FBACK",
43410e27a4SGerrit Renker [TFRC_SSTATE_FBACK] = "FBACK",
44410e27a4SGerrit Renker };
45410e27a4SGerrit Renker
46410e27a4SGerrit Renker return ccid3_state_names[state];
47410e27a4SGerrit Renker }
48410e27a4SGerrit Renker #endif
49410e27a4SGerrit Renker
ccid3_hc_tx_set_state(struct sock * sk,enum ccid3_hc_tx_states state)50410e27a4SGerrit Renker static void ccid3_hc_tx_set_state(struct sock *sk,
51410e27a4SGerrit Renker enum ccid3_hc_tx_states state)
52410e27a4SGerrit Renker {
53996ccf49SGerrit Renker struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
54996ccf49SGerrit Renker enum ccid3_hc_tx_states oldstate = hc->tx_state;
55410e27a4SGerrit Renker
56410e27a4SGerrit Renker ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
57410e27a4SGerrit Renker dccp_role(sk), sk, ccid3_tx_state_name(oldstate),
58410e27a4SGerrit Renker ccid3_tx_state_name(state));
59410e27a4SGerrit Renker WARN_ON(state == oldstate);
60996ccf49SGerrit Renker hc->tx_state = state;
61410e27a4SGerrit Renker }
627c657876SArnaldo Carvalho de Melo
6317893bc1SGerrit Renker /*
646c08b2cfSGerrit Renker * Compute the initial sending rate X_init in the manner of RFC 3390:
656c08b2cfSGerrit Renker *
66410e27a4SGerrit Renker * X_init = min(4 * s, max(2 * s, 4380 bytes)) / RTT
676c08b2cfSGerrit Renker *
68410e27a4SGerrit Renker * Note that RFC 3390 uses MSS, RFC 4342 refers to RFC 3390, and rfc3448bis
69410e27a4SGerrit Renker * (rev-02) clarifies the use of RFC 3390 with regard to the above formula.
70a21f9f96SGerrit Renker * For consistency with other parts of the code, X_init is scaled by 2^6.
71a21f9f96SGerrit Renker */
rfc3390_initial_rate(struct sock * sk)72a21f9f96SGerrit Renker static inline u64 rfc3390_initial_rate(struct sock *sk)
73a21f9f96SGerrit Renker {
74996ccf49SGerrit Renker const struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
75996ccf49SGerrit Renker const __u32 w_init = clamp_t(__u32, 4380U, 2 * hc->tx_s, 4 * hc->tx_s);
76a21f9f96SGerrit Renker
77996ccf49SGerrit Renker return scaled_div(w_init << 6, hc->tx_rtt);
78a21f9f96SGerrit Renker }
79a21f9f96SGerrit Renker
8020cbd3e1SGerrit Renker /**
8120cbd3e1SGerrit Renker * ccid3_update_send_interval - Calculate new t_ipi = s / X_inst
82*0b609b55SAndrew Lunn * @hc: socket to have the send interval updated
83*0b609b55SAndrew Lunn *
8420cbd3e1SGerrit Renker * This respects the granularity of X_inst (64 * bytes/second).
8517893bc1SGerrit Renker */
ccid3_update_send_interval(struct ccid3_hc_tx_sock * hc)86996ccf49SGerrit Renker static void ccid3_update_send_interval(struct ccid3_hc_tx_sock *hc)
877c657876SArnaldo Carvalho de Melo {
88996ccf49SGerrit Renker hc->tx_t_ipi = scaled_div32(((u64)hc->tx_s) << 6, hc->tx_x);
89410e27a4SGerrit Renker
90793734b5SGerrit Renker DCCP_BUG_ON(hc->tx_t_ipi == 0);
9120cbd3e1SGerrit Renker ccid3_pr_debug("t_ipi=%u, s=%u, X=%u\n", hc->tx_t_ipi,
9295c96174SEric Dumazet hc->tx_s, (unsigned int)(hc->tx_x >> 6));
937c657876SArnaldo Carvalho de Melo }
94aa97efd9SGerrit Renker
ccid3_hc_tx_idle_rtt(struct ccid3_hc_tx_sock * hc,ktime_t now)95996ccf49SGerrit Renker static u32 ccid3_hc_tx_idle_rtt(struct ccid3_hc_tx_sock *hc, ktime_t now)
96a5358fdcSGerrit Renker {
97996ccf49SGerrit Renker u32 delta = ktime_us_delta(now, hc->tx_t_last_win_count);
98a5358fdcSGerrit Renker
99996ccf49SGerrit Renker return delta / hc->tx_rtt;
100a5358fdcSGerrit Renker }
101a5358fdcSGerrit Renker
102aa97efd9SGerrit Renker /**
103aa97efd9SGerrit Renker * ccid3_hc_tx_update_x - Update allowed sending rate X
104*0b609b55SAndrew Lunn * @sk: socket to be updated
105aa97efd9SGerrit Renker * @stamp: most recent time if available - can be left NULL.
1062c53040fSBen Hutchings *
107aa97efd9SGerrit Renker * This function tracks draft rfc3448bis, check there for latest details.
1085c3fbb6aSGerrit Renker *
1091a21e49aSGerrit Renker * Note: X and X_recv are both stored in units of 64 * bytes/second, to support
1101a21e49aSGerrit Renker * fine-grained resolution of sending rates. This requires scaling by 2^6
1111a21e49aSGerrit Renker * throughout the code. Only X_calc is unscaled (in bytes/second).
1121a21e49aSGerrit Renker *
1137c657876SArnaldo Carvalho de Melo */
ccid3_hc_tx_update_x(struct sock * sk,ktime_t * stamp)114aa97efd9SGerrit Renker static void ccid3_hc_tx_update_x(struct sock *sk, ktime_t *stamp)
1157c657876SArnaldo Carvalho de Melo {
116996ccf49SGerrit Renker struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
117996ccf49SGerrit Renker __u64 min_rate = 2 * hc->tx_x_recv;
118996ccf49SGerrit Renker const __u64 old_x = hc->tx_x;
119aa97efd9SGerrit Renker ktime_t now = stamp ? *stamp : ktime_get_real();
1207c657876SArnaldo Carvalho de Melo
1210c150efbSGerrit Renker /*
1220c150efbSGerrit Renker * Handle IDLE periods: do not reduce below RFC3390 initial sending rate
123a5358fdcSGerrit Renker * when idling [RFC 4342, 5.1]. Definition of idling is from rfc3448bis:
124a5358fdcSGerrit Renker * a sender is idle if it has not sent anything over a 2-RTT-period.
1250c150efbSGerrit Renker * For consistency with X and X_recv, min_rate is also scaled by 2^6.
1260c150efbSGerrit Renker */
127996ccf49SGerrit Renker if (ccid3_hc_tx_idle_rtt(hc, now) >= 2) {
1280c150efbSGerrit Renker min_rate = rfc3390_initial_rate(sk);
129996ccf49SGerrit Renker min_rate = max(min_rate, 2 * hc->tx_x_recv);
1300c150efbSGerrit Renker }
1310c150efbSGerrit Renker
132996ccf49SGerrit Renker if (hc->tx_p > 0) {
1331a21e49aSGerrit Renker
134996ccf49SGerrit Renker hc->tx_x = min(((__u64)hc->tx_x_calc) << 6, min_rate);
135996ccf49SGerrit Renker hc->tx_x = max(hc->tx_x, (((__u64)hc->tx_s) << 6) / TFRC_T_MBI);
136b6ee3d4aSArnaldo Carvalho de Melo
137996ccf49SGerrit Renker } else if (ktime_us_delta(now, hc->tx_t_ld) - (s64)hc->tx_rtt >= 0) {
1381a21e49aSGerrit Renker
139996ccf49SGerrit Renker hc->tx_x = min(2 * hc->tx_x, min_rate);
140996ccf49SGerrit Renker hc->tx_x = max(hc->tx_x,
141996ccf49SGerrit Renker scaled_div(((__u64)hc->tx_s) << 6, hc->tx_rtt));
142996ccf49SGerrit Renker hc->tx_t_ld = now;
143ac198ea8SArnaldo Carvalho de Melo }
144a79ef76fSGerrit Renker
145996ccf49SGerrit Renker if (hc->tx_x != old_x) {
1461761f7d7SGerrit Renker ccid3_pr_debug("X_prev=%u, X_now=%u, X_calc=%u, "
14795c96174SEric Dumazet "X_recv=%u\n", (unsigned int)(old_x >> 6),
14895c96174SEric Dumazet (unsigned int)(hc->tx_x >> 6), hc->tx_x_calc,
14995c96174SEric Dumazet (unsigned int)(hc->tx_x_recv >> 6));
1508699be7dSIan McDonald
151996ccf49SGerrit Renker ccid3_update_send_interval(hc);
1527c657876SArnaldo Carvalho de Melo }
1538699be7dSIan McDonald }
1547c657876SArnaldo Carvalho de Melo
1552c53040fSBen Hutchings /**
1562c53040fSBen Hutchings * ccid3_hc_tx_update_s - Track the mean packet size `s'
157*0b609b55SAndrew Lunn * @hc: socket to be updated
158410e27a4SGerrit Renker * @len: DCCP packet payload size in bytes
1592c53040fSBen Hutchings *
1602c53040fSBen Hutchings * cf. RFC 4342, 5.3 and RFC 3448, 4.1
16178ad713dSGerrit Renker */
ccid3_hc_tx_update_s(struct ccid3_hc_tx_sock * hc,int len)162996ccf49SGerrit Renker static inline void ccid3_hc_tx_update_s(struct ccid3_hc_tx_sock *hc, int len)
16378ad713dSGerrit Renker {
164996ccf49SGerrit Renker const u16 old_s = hc->tx_s;
165410e27a4SGerrit Renker
166996ccf49SGerrit Renker hc->tx_s = tfrc_ewma(hc->tx_s, len, 9);
167410e27a4SGerrit Renker
168996ccf49SGerrit Renker if (hc->tx_s != old_s)
169996ccf49SGerrit Renker ccid3_update_send_interval(hc);
17078ad713dSGerrit Renker }
17178ad713dSGerrit Renker
1729f8681dbSGerrit Renker /*
1739f8681dbSGerrit Renker * Update Window Counter using the algorithm from [RFC 4342, 8.1].
174825de27dSGerrit Renker * As elsewhere, RTT > 0 is assumed by using dccp_sample_rtt().
1759f8681dbSGerrit Renker */
ccid3_hc_tx_update_win_count(struct ccid3_hc_tx_sock * hc,ktime_t now)176996ccf49SGerrit Renker static inline void ccid3_hc_tx_update_win_count(struct ccid3_hc_tx_sock *hc,
1778132da4dSGerrit Renker ktime_t now)
1789f8681dbSGerrit Renker {
179996ccf49SGerrit Renker u32 delta = ktime_us_delta(now, hc->tx_t_last_win_count),
180996ccf49SGerrit Renker quarter_rtts = (4 * delta) / hc->tx_rtt;
1819f8681dbSGerrit Renker
1829f8681dbSGerrit Renker if (quarter_rtts > 0) {
183996ccf49SGerrit Renker hc->tx_t_last_win_count = now;
184996ccf49SGerrit Renker hc->tx_last_win_count += min(quarter_rtts, 5U);
185996ccf49SGerrit Renker hc->tx_last_win_count &= 0xF; /* mod 16 */
1869f8681dbSGerrit Renker }
1879f8681dbSGerrit Renker }
1889f8681dbSGerrit Renker
ccid3_hc_tx_no_feedback_timer(struct timer_list * t)189839a6094SKees Cook static void ccid3_hc_tx_no_feedback_timer(struct timer_list *t)
1907c657876SArnaldo Carvalho de Melo {
191839a6094SKees Cook struct ccid3_hc_tx_sock *hc = from_timer(hc, t, tx_no_feedback_timer);
192839a6094SKees Cook struct sock *sk = hc->sk;
1932a1fda6fSGerrit Renker unsigned long t_nfb = USEC_PER_SEC / 5;
1947c657876SArnaldo Carvalho de Melo
1957c657876SArnaldo Carvalho de Melo bh_lock_sock(sk);
1967c657876SArnaldo Carvalho de Melo if (sock_owned_by_user(sk)) {
1977c657876SArnaldo Carvalho de Melo /* Try again later. */
1987c657876SArnaldo Carvalho de Melo /* XXX: set some sensible MIB */
19948e03eeeSGerrit Renker goto restart_timer;
2007c657876SArnaldo Carvalho de Melo }
2017c657876SArnaldo Carvalho de Melo
202410e27a4SGerrit Renker ccid3_pr_debug("%s(%p, state=%s) - entry\n", dccp_role(sk), sk,
203996ccf49SGerrit Renker ccid3_tx_state_name(hc->tx_state));
2047c657876SArnaldo Carvalho de Melo
20580763dfbSGerrit Renker /* Ignore and do not restart after leaving the established state */
20680763dfbSGerrit Renker if ((1 << sk->sk_state) & ~(DCCPF_OPEN | DCCPF_PARTOPEN))
20780763dfbSGerrit Renker goto out;
20880763dfbSGerrit Renker
20980763dfbSGerrit Renker /* Reset feedback state to "no feedback received" */
210996ccf49SGerrit Renker if (hc->tx_state == TFRC_SSTATE_FBACK)
211410e27a4SGerrit Renker ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
212d0995e6aSGerrit Renker
21352515e77SGerrit Renker /*
21452515e77SGerrit Renker * Determine new allowed sending rate X as per draft rfc3448bis-00, 4.4
21567b67e36SGerrit Renker * RTO is 0 if and only if no feedback has been received yet.
21652515e77SGerrit Renker */
21767b67e36SGerrit Renker if (hc->tx_t_rto == 0 || hc->tx_p == 0) {
21852515e77SGerrit Renker
21952515e77SGerrit Renker /* halve send rate directly */
220996ccf49SGerrit Renker hc->tx_x = max(hc->tx_x / 2,
221996ccf49SGerrit Renker (((__u64)hc->tx_s) << 6) / TFRC_T_MBI);
222996ccf49SGerrit Renker ccid3_update_send_interval(hc);
22352515e77SGerrit Renker } else {
2241f2333aeSArnaldo Carvalho de Melo /*
22552515e77SGerrit Renker * Modify the cached value of X_recv
226ff586298SGerrit Renker *
22752515e77SGerrit Renker * If (X_calc > 2 * X_recv)
2287c657876SArnaldo Carvalho de Melo * X_recv = max(X_recv / 2, s / (2 * t_mbi));
2297c657876SArnaldo Carvalho de Melo * Else
2307c657876SArnaldo Carvalho de Melo * X_recv = X_calc / 4;
2311a21e49aSGerrit Renker *
2321a21e49aSGerrit Renker * Note that X_recv is scaled by 2^6 while X_calc is not
2337c657876SArnaldo Carvalho de Melo */
234996ccf49SGerrit Renker if (hc->tx_x_calc > (hc->tx_x_recv >> 5))
235996ccf49SGerrit Renker hc->tx_x_recv =
236996ccf49SGerrit Renker max(hc->tx_x_recv / 2,
237996ccf49SGerrit Renker (((__u64)hc->tx_s) << 6) / (2*TFRC_T_MBI));
23852515e77SGerrit Renker else {
239996ccf49SGerrit Renker hc->tx_x_recv = hc->tx_x_calc;
240996ccf49SGerrit Renker hc->tx_x_recv <<= 4;
2419e8efc82SGerrit Renker }
242aa97efd9SGerrit Renker ccid3_hc_tx_update_x(sk, NULL);
24352515e77SGerrit Renker }
24452515e77SGerrit Renker ccid3_pr_debug("Reduced X to %llu/64 bytes/sec\n",
245996ccf49SGerrit Renker (unsigned long long)hc->tx_x);
24652515e77SGerrit Renker
2476b5e633aSArnaldo Carvalho de Melo /*
24852515e77SGerrit Renker * Set new timeout for the nofeedback timer.
2498a508ac2SGerrit Renker * See comments in packet_recv() regarding the value of t_RTO.
2506b5e633aSArnaldo Carvalho de Melo */
25167b67e36SGerrit Renker if (unlikely(hc->tx_t_rto == 0)) /* no feedback received yet */
25252515e77SGerrit Renker t_nfb = TFRC_INITIAL_TIMEOUT;
25352515e77SGerrit Renker else
254996ccf49SGerrit Renker t_nfb = max(hc->tx_t_rto, 2 * hc->tx_t_ipi);
2557c657876SArnaldo Carvalho de Melo
25648e03eeeSGerrit Renker restart_timer:
257996ccf49SGerrit Renker sk_reset_timer(sk, &hc->tx_no_feedback_timer,
2582a1fda6fSGerrit Renker jiffies + usecs_to_jiffies(t_nfb));
2597c657876SArnaldo Carvalho de Melo out:
2607c657876SArnaldo Carvalho de Melo bh_unlock_sock(sk);
2617c657876SArnaldo Carvalho de Melo sock_put(sk);
2627c657876SArnaldo Carvalho de Melo }
2637c657876SArnaldo Carvalho de Melo
264fe84f414SGerrit Renker /**
265fe84f414SGerrit Renker * ccid3_hc_tx_send_packet - Delay-based dequeueing of TX packets
266*0b609b55SAndrew Lunn * @sk: socket to send packet from
267fe84f414SGerrit Renker * @skb: next packet candidate to send on @sk
2682c53040fSBen Hutchings *
269fe84f414SGerrit Renker * This function uses the convention of ccid_packet_dequeue_eval() and
270fe84f414SGerrit Renker * returns a millisecond-delay value between 0 and t_mbi = 64000 msec.
2717da7f456SGerrit Renker */
ccid3_hc_tx_send_packet(struct sock * sk,struct sk_buff * skb)2726b57c93dSGerrit Renker static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
2737c657876SArnaldo Carvalho de Melo {
2747c657876SArnaldo Carvalho de Melo struct dccp_sock *dp = dccp_sk(sk);
275996ccf49SGerrit Renker struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
2768132da4dSGerrit Renker ktime_t now = ktime_get_real();
2778132da4dSGerrit Renker s64 delay;
2787c657876SArnaldo Carvalho de Melo
2797c657876SArnaldo Carvalho de Melo /*
280da335bafSGerrit Renker * This function is called only for Data and DataAck packets. Sending
281da335bafSGerrit Renker * zero-sized Data(Ack)s is theoretically possible, but for congestion
282da335bafSGerrit Renker * control this case is pathological - ignore it.
2837c657876SArnaldo Carvalho de Melo */
2846b57c93dSGerrit Renker if (unlikely(skb->len == 0))
285da335bafSGerrit Renker return -EBADMSG;
2867c657876SArnaldo Carvalho de Melo
28780763dfbSGerrit Renker if (hc->tx_state == TFRC_SSTATE_NO_SENT) {
288996ccf49SGerrit Renker sk_reset_timer(sk, &hc->tx_no_feedback_timer, (jiffies +
2898109b02bSArnaldo Carvalho de Melo usecs_to_jiffies(TFRC_INITIAL_TIMEOUT)));
290996ccf49SGerrit Renker hc->tx_last_win_count = 0;
291996ccf49SGerrit Renker hc->tx_t_last_win_count = now;
29290feeb95SGerrit Renker
29390feeb95SGerrit Renker /* Set t_0 for initial packet */
294996ccf49SGerrit Renker hc->tx_t_nom = now;
295410e27a4SGerrit Renker
296996ccf49SGerrit Renker hc->tx_s = skb->len;
29730833ffeSGerrit Renker
29830833ffeSGerrit Renker /*
29930833ffeSGerrit Renker * Use initial RTT sample when available: recommended by erratum
30030833ffeSGerrit Renker * to RFC 4342. This implements the initialisation procedure of
30130833ffeSGerrit Renker * draft rfc3448bis, section 4.2. Remember, X is scaled by 2^6.
30230833ffeSGerrit Renker */
30330833ffeSGerrit Renker if (dp->dccps_syn_rtt) {
30430833ffeSGerrit Renker ccid3_pr_debug("SYN RTT = %uus\n", dp->dccps_syn_rtt);
305996ccf49SGerrit Renker hc->tx_rtt = dp->dccps_syn_rtt;
306996ccf49SGerrit Renker hc->tx_x = rfc3390_initial_rate(sk);
307996ccf49SGerrit Renker hc->tx_t_ld = now;
30830833ffeSGerrit Renker } else {
3093294f202SGerrit Renker /*
3103294f202SGerrit Renker * Sender does not have RTT sample:
3113294f202SGerrit Renker * - set fallback RTT (RFC 4340, 3.4) since a RTT value
3123294f202SGerrit Renker * is needed in several parts (e.g. window counter);
3133294f202SGerrit Renker * - set sending rate X_pps = 1pps as per RFC 3448, 4.2.
3143294f202SGerrit Renker */
315996ccf49SGerrit Renker hc->tx_rtt = DCCP_FALLBACK_RTT;
316996ccf49SGerrit Renker hc->tx_x = hc->tx_s;
317996ccf49SGerrit Renker hc->tx_x <<= 6;
31830833ffeSGerrit Renker }
319996ccf49SGerrit Renker ccid3_update_send_interval(hc);
32030833ffeSGerrit Renker
321410e27a4SGerrit Renker ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
32280763dfbSGerrit Renker
32380763dfbSGerrit Renker } else {
324996ccf49SGerrit Renker delay = ktime_us_delta(hc->tx_t_nom, now);
3258699be7dSIan McDonald ccid3_pr_debug("delay=%ld\n", (long)delay);
32691cf5a17SGerrit Renker /*
32720cbd3e1SGerrit Renker * Scheduling of packet transmissions (RFC 5348, 8.3)
32891cf5a17SGerrit Renker *
32991cf5a17SGerrit Renker * if (t_now > t_nom - delta)
33091cf5a17SGerrit Renker * // send the packet now
33191cf5a17SGerrit Renker * else
33291cf5a17SGerrit Renker * // send the packet in (t_nom - t_now) milliseconds.
33391cf5a17SGerrit Renker */
33420cbd3e1SGerrit Renker if (delay >= TFRC_T_DELTA)
33520cbd3e1SGerrit Renker return (u32)delay / USEC_PER_MSEC;
3369f8681dbSGerrit Renker
337996ccf49SGerrit Renker ccid3_hc_tx_update_win_count(hc, now);
3387c657876SArnaldo Carvalho de Melo }
3397c657876SArnaldo Carvalho de Melo
3407da7f456SGerrit Renker /* prepare to send now (add options etc.) */
341507d37cfSArnaldo Carvalho de Melo dp->dccps_hc_tx_insert_options = 1;
342996ccf49SGerrit Renker DCCP_SKB_CB(skb)->dccpd_ccval = hc->tx_last_win_count;
343e312d100SGerrit Renker
344e312d100SGerrit Renker /* set the nominal send time for the next following packet */
345996ccf49SGerrit Renker hc->tx_t_nom = ktime_add_us(hc->tx_t_nom, hc->tx_t_ipi);
346fe84f414SGerrit Renker return CCID_PACKET_SEND_AT_ONCE;
3477c657876SArnaldo Carvalho de Melo }
3487c657876SArnaldo Carvalho de Melo
ccid3_hc_tx_packet_sent(struct sock * sk,unsigned int len)349baf9e782SGerrit Renker static void ccid3_hc_tx_packet_sent(struct sock *sk, unsigned int len)
3507c657876SArnaldo Carvalho de Melo {
351996ccf49SGerrit Renker struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
3527c657876SArnaldo Carvalho de Melo
353996ccf49SGerrit Renker ccid3_hc_tx_update_s(hc, len);
35478ad713dSGerrit Renker
355996ccf49SGerrit Renker if (tfrc_tx_hist_add(&hc->tx_hist, dccp_sk(sk)->dccps_gss))
356c5a1ae9aSGerrit Renker DCCP_CRIT("packet history - out of memory!");
3577c657876SArnaldo Carvalho de Melo }
3587c657876SArnaldo Carvalho de Melo
ccid3_hc_tx_packet_recv(struct sock * sk,struct sk_buff * skb)3597c657876SArnaldo Carvalho de Melo static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
3607c657876SArnaldo Carvalho de Melo {
361996ccf49SGerrit Renker struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
362d2c72630SGerrit Renker struct tfrc_tx_hist_entry *acked;
3630740d49cSArnaldo Carvalho de Melo ktime_t now;
3642a1fda6fSGerrit Renker unsigned long t_nfb;
365536bb20bSGerrit Renker u32 r_sample;
3661f2333aeSArnaldo Carvalho de Melo
3677c657876SArnaldo Carvalho de Melo /* we are only interested in ACKs */
3687c657876SArnaldo Carvalho de Melo if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK ||
3697c657876SArnaldo Carvalho de Melo DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_DATAACK))
3707c657876SArnaldo Carvalho de Melo return;
371d2c72630SGerrit Renker /*
372d2c72630SGerrit Renker * Locate the acknowledged packet in the TX history.
373d2c72630SGerrit Renker *
374d2c72630SGerrit Renker * Returning "entry not found" here can for instance happen when
375d2c72630SGerrit Renker * - the host has not sent out anything (e.g. a passive server),
376d2c72630SGerrit Renker * - the Ack is outdated (packet with higher Ack number was received),
377d2c72630SGerrit Renker * - it is a bogus Ack (for a packet not sent on this connection).
378d2c72630SGerrit Renker */
379d2c72630SGerrit Renker acked = tfrc_tx_hist_find_entry(hc->tx_hist, dccp_hdr_ack_seq(skb));
380d2c72630SGerrit Renker if (acked == NULL)
381410e27a4SGerrit Renker return;
382d2c72630SGerrit Renker /* For the sake of RTT sampling, ignore/remove all older entries */
383d2c72630SGerrit Renker tfrc_tx_hist_purge(&acked->next);
384d2c72630SGerrit Renker
385d2c72630SGerrit Renker /* Update the moving average for the RTT estimate (RFC 3448, 4.3) */
386d2c72630SGerrit Renker now = ktime_get_real();
387d2c72630SGerrit Renker r_sample = dccp_sample_rtt(sk, ktime_us_delta(now, acked->stamp));
388d2c72630SGerrit Renker hc->tx_rtt = tfrc_ewma(hc->tx_rtt, r_sample, 9);
389410e27a4SGerrit Renker
3901a21e49aSGerrit Renker /*
391d8d1252fSGerrit Renker * Update allowed sending rate X as per draft rfc3448bis-00, 4.2/3
392d8d1252fSGerrit Renker */
393996ccf49SGerrit Renker if (hc->tx_state == TFRC_SSTATE_NO_FBACK) {
394410e27a4SGerrit Renker ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK);
395d8d1252fSGerrit Renker
396996ccf49SGerrit Renker if (hc->tx_t_rto == 0) {
397d8d1252fSGerrit Renker /*
398d8d1252fSGerrit Renker * Initial feedback packet: Larger Initial Windows (4.2)
3991a21e49aSGerrit Renker */
400996ccf49SGerrit Renker hc->tx_x = rfc3390_initial_rate(sk);
401996ccf49SGerrit Renker hc->tx_t_ld = now;
402a79ef76fSGerrit Renker
403996ccf49SGerrit Renker ccid3_update_send_interval(hc);
4045c3fbb6aSGerrit Renker
405d8d1252fSGerrit Renker goto done_computing_x;
406996ccf49SGerrit Renker } else if (hc->tx_p == 0) {
407d8d1252fSGerrit Renker /*
408d8d1252fSGerrit Renker * First feedback after nofeedback timer expiry (4.3)
409d8d1252fSGerrit Renker */
410d8d1252fSGerrit Renker goto done_computing_x;
411d8d1252fSGerrit Renker }
412d8d1252fSGerrit Renker }
4135c3fbb6aSGerrit Renker
414ff586298SGerrit Renker /* Update sending rate (step 4 of [RFC 3448, 4.3]) */
415996ccf49SGerrit Renker if (hc->tx_p > 0)
416996ccf49SGerrit Renker hc->tx_x_calc = tfrc_calc_x(hc->tx_s, hc->tx_rtt, hc->tx_p);
417aa97efd9SGerrit Renker ccid3_hc_tx_update_x(sk, &now);
4187c657876SArnaldo Carvalho de Melo
419d8d1252fSGerrit Renker done_computing_x:
4207dfee1a9SGerrit Renker ccid3_pr_debug("%s(%p), RTT=%uus (sample=%uus), s=%u, "
4218109b02bSArnaldo Carvalho de Melo "p=%u, X_calc=%u, X_recv=%u, X=%u\n",
422996ccf49SGerrit Renker dccp_role(sk), sk, hc->tx_rtt, r_sample,
423996ccf49SGerrit Renker hc->tx_s, hc->tx_p, hc->tx_x_calc,
42495c96174SEric Dumazet (unsigned int)(hc->tx_x_recv >> 6),
42595c96174SEric Dumazet (unsigned int)(hc->tx_x >> 6));
4267c657876SArnaldo Carvalho de Melo
4277c657876SArnaldo Carvalho de Melo /* unschedule no feedback timer */
428996ccf49SGerrit Renker sk_stop_timer(sk, &hc->tx_no_feedback_timer);
4297c657876SArnaldo Carvalho de Melo
430c530cfb1SArnaldo Carvalho de Melo /*
4318109b02bSArnaldo Carvalho de Melo * As we have calculated new ipi, delta, t_nom it is possible
4328109b02bSArnaldo Carvalho de Melo * that we now can send a packet, so wake up dccp_wait_for_ccid
433c530cfb1SArnaldo Carvalho de Melo */
434c530cfb1SArnaldo Carvalho de Melo sk->sk_write_space(sk);
4358c60f3faSArnaldo Carvalho de Melo
4368a508ac2SGerrit Renker /*
43789858ad1SGerrit Renker * Update timeout interval for the nofeedback timer. In order to control
43889858ad1SGerrit Renker * rate halving on networks with very low RTTs (<= 1 ms), use per-route
43989858ad1SGerrit Renker * tunable RTAX_RTO_MIN value as the lower bound.
4408a508ac2SGerrit Renker */
44189858ad1SGerrit Renker hc->tx_t_rto = max_t(u32, 4 * hc->tx_rtt,
44289858ad1SGerrit Renker USEC_PER_SEC/HZ * tcp_rto_min(sk));
4431f2333aeSArnaldo Carvalho de Melo /*
4441f2333aeSArnaldo Carvalho de Melo * Schedule no feedback timer to expire in
4458a508ac2SGerrit Renker * max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi)
4461f2333aeSArnaldo Carvalho de Melo */
447996ccf49SGerrit Renker t_nfb = max(hc->tx_t_rto, 2 * hc->tx_t_ipi);
4487c657876SArnaldo Carvalho de Melo
449a9672411SGerrit Renker ccid3_pr_debug("%s(%p), Scheduled no feedback timer to "
4508109b02bSArnaldo Carvalho de Melo "expire in %lu jiffies (%luus)\n",
451388d5e99SGerrit Renker dccp_role(sk), sk, usecs_to_jiffies(t_nfb), t_nfb);
4527c657876SArnaldo Carvalho de Melo
453996ccf49SGerrit Renker sk_reset_timer(sk, &hc->tx_no_feedback_timer,
4542a1fda6fSGerrit Renker jiffies + usecs_to_jiffies(t_nfb));
4557c657876SArnaldo Carvalho de Melo }
4567c657876SArnaldo Carvalho de Melo
ccid3_hc_tx_parse_options(struct sock * sk,u8 packet_type,u8 option,u8 * optval,u8 optlen)4574874c131SGerrit Renker static int ccid3_hc_tx_parse_options(struct sock *sk, u8 packet_type,
4584874c131SGerrit Renker u8 option, u8 *optval, u8 optlen)
4597c657876SArnaldo Carvalho de Melo {
460996ccf49SGerrit Renker struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
46176fd1e87SGerrit Renker __be32 opt_val;
4627c657876SArnaldo Carvalho de Melo
4637c657876SArnaldo Carvalho de Melo switch (option) {
46437efb03fSGerrit Renker case TFRC_OPT_RECEIVE_RATE:
4657c657876SArnaldo Carvalho de Melo case TFRC_OPT_LOSS_EVENT_RATE:
4664874c131SGerrit Renker /* Must be ignored on Data packets, cf. RFC 4342 8.3 and 8.5 */
4674874c131SGerrit Renker if (packet_type == DCCP_PKT_DATA)
4684874c131SGerrit Renker break;
4694874c131SGerrit Renker if (unlikely(optlen != 4)) {
47037efb03fSGerrit Renker DCCP_WARN("%s(%p), invalid len %d for %u\n",
4714874c131SGerrit Renker dccp_role(sk), sk, optlen, option);
47237efb03fSGerrit Renker return -EINVAL;
47347a61e7bSGerrit Renker }
4744874c131SGerrit Renker opt_val = ntohl(get_unaligned((__be32 *)optval));
475410e27a4SGerrit Renker
47637efb03fSGerrit Renker if (option == TFRC_OPT_RECEIVE_RATE) {
477536bb20bSGerrit Renker /* Receive Rate is kept in units of 64 bytes/second */
478536bb20bSGerrit Renker hc->tx_x_recv = opt_val;
479536bb20bSGerrit Renker hc->tx_x_recv <<= 6;
480536bb20bSGerrit Renker
48137efb03fSGerrit Renker ccid3_pr_debug("%s(%p), RECEIVE_RATE=%u\n",
48237efb03fSGerrit Renker dccp_role(sk), sk, opt_val);
48337efb03fSGerrit Renker } else {
484536bb20bSGerrit Renker /* Update the fixpoint Loss Event Rate fraction */
485536bb20bSGerrit Renker hc->tx_p = tfrc_invert_loss_event_rate(opt_val);
486536bb20bSGerrit Renker
48737efb03fSGerrit Renker ccid3_pr_debug("%s(%p), LOSS_EVENT_RATE=%u\n",
48837efb03fSGerrit Renker dccp_role(sk), sk, opt_val);
48937efb03fSGerrit Renker }
49037efb03fSGerrit Renker }
49137efb03fSGerrit Renker return 0;
4927c657876SArnaldo Carvalho de Melo }
4937c657876SArnaldo Carvalho de Melo
ccid3_hc_tx_init(struct ccid * ccid,struct sock * sk)49491f0ebf7SArnaldo Carvalho de Melo static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk)
4957c657876SArnaldo Carvalho de Melo {
496996ccf49SGerrit Renker struct ccid3_hc_tx_sock *hc = ccid_priv(ccid);
4977c657876SArnaldo Carvalho de Melo
498996ccf49SGerrit Renker hc->tx_state = TFRC_SSTATE_NO_SENT;
499996ccf49SGerrit Renker hc->tx_hist = NULL;
500839a6094SKees Cook hc->sk = sk;
501839a6094SKees Cook timer_setup(&hc->tx_no_feedback_timer,
502839a6094SKees Cook ccid3_hc_tx_no_feedback_timer, 0);
5037c657876SArnaldo Carvalho de Melo return 0;
5047c657876SArnaldo Carvalho de Melo }
5057c657876SArnaldo Carvalho de Melo
ccid3_hc_tx_exit(struct sock * sk)5067c657876SArnaldo Carvalho de Melo static void ccid3_hc_tx_exit(struct sock *sk)
5077c657876SArnaldo Carvalho de Melo {
508996ccf49SGerrit Renker struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
5097c657876SArnaldo Carvalho de Melo
510996ccf49SGerrit Renker sk_stop_timer(sk, &hc->tx_no_feedback_timer);
511996ccf49SGerrit Renker tfrc_tx_hist_purge(&hc->tx_hist);
5127c657876SArnaldo Carvalho de Melo }
5137c657876SArnaldo Carvalho de Melo
ccid3_hc_tx_get_info(struct sock * sk,struct tcp_info * info)5149bf17475SGerrit Renker static void ccid3_hc_tx_get_info(struct sock *sk, struct tcp_info *info)
5159bf17475SGerrit Renker {
51651c22bb5SGerrit Renker info->tcpi_rto = ccid3_hc_tx_sk(sk)->tx_t_rto;
51751c22bb5SGerrit Renker info->tcpi_rtt = ccid3_hc_tx_sk(sk)->tx_rtt;
5189bf17475SGerrit Renker }
5199bf17475SGerrit Renker
ccid3_hc_tx_getsockopt(struct sock * sk,const int optname,int len,u32 __user * optval,int __user * optlen)5209bf17475SGerrit Renker static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len,
5219bf17475SGerrit Renker u32 __user *optval, int __user *optlen)
5229bf17475SGerrit Renker {
52351c22bb5SGerrit Renker const struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
52467b67e36SGerrit Renker struct tfrc_tx_info tfrc;
5259bf17475SGerrit Renker const void *val;
5269bf17475SGerrit Renker
5279bf17475SGerrit Renker switch (optname) {
5289bf17475SGerrit Renker case DCCP_SOCKOPT_CCID_TX_INFO:
52967b67e36SGerrit Renker if (len < sizeof(tfrc))
5309bf17475SGerrit Renker return -EINVAL;
5317b07f8ebSMathias Krause memset(&tfrc, 0, sizeof(tfrc));
53267b67e36SGerrit Renker tfrc.tfrctx_x = hc->tx_x;
53367b67e36SGerrit Renker tfrc.tfrctx_x_recv = hc->tx_x_recv;
53467b67e36SGerrit Renker tfrc.tfrctx_x_calc = hc->tx_x_calc;
53567b67e36SGerrit Renker tfrc.tfrctx_rtt = hc->tx_rtt;
53667b67e36SGerrit Renker tfrc.tfrctx_p = hc->tx_p;
53767b67e36SGerrit Renker tfrc.tfrctx_rto = hc->tx_t_rto;
53867b67e36SGerrit Renker tfrc.tfrctx_ipi = hc->tx_t_ipi;
53967b67e36SGerrit Renker len = sizeof(tfrc);
54067b67e36SGerrit Renker val = &tfrc;
5419bf17475SGerrit Renker break;
5429bf17475SGerrit Renker default:
5439bf17475SGerrit Renker return -ENOPROTOOPT;
5449bf17475SGerrit Renker }
5459bf17475SGerrit Renker
5469bf17475SGerrit Renker if (put_user(len, optlen) || copy_to_user(optval, val, len))
5479bf17475SGerrit Renker return -EFAULT;
5489bf17475SGerrit Renker
5499bf17475SGerrit Renker return 0;
5509bf17475SGerrit Renker }
5519bf17475SGerrit Renker
5529bf17475SGerrit Renker /*
5539bf17475SGerrit Renker * Receiver Half-Connection Routines
5549bf17475SGerrit Renker */
555410e27a4SGerrit Renker
556410e27a4SGerrit Renker /* CCID3 feedback types */
557410e27a4SGerrit Renker enum ccid3_fback_type {
558410e27a4SGerrit Renker CCID3_FBACK_NONE = 0,
559410e27a4SGerrit Renker CCID3_FBACK_INITIAL,
560410e27a4SGerrit Renker CCID3_FBACK_PERIODIC,
561410e27a4SGerrit Renker CCID3_FBACK_PARAM_CHANGE
562410e27a4SGerrit Renker };
563410e27a4SGerrit Renker
564410e27a4SGerrit Renker #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
ccid3_rx_state_name(enum ccid3_hc_rx_states state)565410e27a4SGerrit Renker static const char *ccid3_rx_state_name(enum ccid3_hc_rx_states state)
566410e27a4SGerrit Renker {
56736cbd3dcSJan Engelhardt static const char *const ccid3_rx_state_names[] = {
568410e27a4SGerrit Renker [TFRC_RSTATE_NO_DATA] = "NO_DATA",
569410e27a4SGerrit Renker [TFRC_RSTATE_DATA] = "DATA",
570410e27a4SGerrit Renker };
571410e27a4SGerrit Renker
572410e27a4SGerrit Renker return ccid3_rx_state_names[state];
573410e27a4SGerrit Renker }
574410e27a4SGerrit Renker #endif
575410e27a4SGerrit Renker
ccid3_hc_rx_set_state(struct sock * sk,enum ccid3_hc_rx_states state)576410e27a4SGerrit Renker static void ccid3_hc_rx_set_state(struct sock *sk,
577410e27a4SGerrit Renker enum ccid3_hc_rx_states state)
578410e27a4SGerrit Renker {
579996ccf49SGerrit Renker struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
580996ccf49SGerrit Renker enum ccid3_hc_rx_states oldstate = hc->rx_state;
581410e27a4SGerrit Renker
582410e27a4SGerrit Renker ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
583410e27a4SGerrit Renker dccp_role(sk), sk, ccid3_rx_state_name(oldstate),
584410e27a4SGerrit Renker ccid3_rx_state_name(state));
585410e27a4SGerrit Renker WARN_ON(state == oldstate);
586996ccf49SGerrit Renker hc->rx_state = state;
587410e27a4SGerrit Renker }
588410e27a4SGerrit Renker
ccid3_hc_rx_send_feedback(struct sock * sk,const struct sk_buff * skb,enum ccid3_fback_type fbtype)589b84a2189SArnaldo Carvalho de Melo static void ccid3_hc_rx_send_feedback(struct sock *sk,
590b84a2189SArnaldo Carvalho de Melo const struct sk_buff *skb,
591b84a2189SArnaldo Carvalho de Melo enum ccid3_fback_type fbtype)
5927c657876SArnaldo Carvalho de Melo {
593996ccf49SGerrit Renker struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
594410e27a4SGerrit Renker struct dccp_sock *dp = dccp_sk(sk);
5950ce4e70fSEric Dumazet ktime_t now = ktime_get();
596410e27a4SGerrit Renker s64 delta = 0;
597410e27a4SGerrit Renker
598b84a2189SArnaldo Carvalho de Melo switch (fbtype) {
599b84a2189SArnaldo Carvalho de Melo case CCID3_FBACK_INITIAL:
600996ccf49SGerrit Renker hc->rx_x_recv = 0;
601996ccf49SGerrit Renker hc->rx_pinv = ~0U; /* see RFC 4342, 8.5 */
6027c657876SArnaldo Carvalho de Melo break;
603b84a2189SArnaldo Carvalho de Melo case CCID3_FBACK_PARAM_CHANGE:
604b84a2189SArnaldo Carvalho de Melo /*
605b84a2189SArnaldo Carvalho de Melo * When parameters change (new loss or p > p_prev), we do not
606b84a2189SArnaldo Carvalho de Melo * have a reliable estimate for R_m of [RFC 3448, 6.2] and so
607410e27a4SGerrit Renker * need to reuse the previous value of X_recv. However, when
608410e27a4SGerrit Renker * X_recv was 0 (due to early loss), this would kill X down to
609410e27a4SGerrit Renker * s/t_mbi (i.e. one packet in 64 seconds).
610410e27a4SGerrit Renker * To avoid such drastic reduction, we approximate X_recv as
611410e27a4SGerrit Renker * the number of bytes since last feedback.
612410e27a4SGerrit Renker * This is a safe fallback, since X is bounded above by X_calc.
613b84a2189SArnaldo Carvalho de Melo */
614996ccf49SGerrit Renker if (hc->rx_x_recv > 0)
615b84a2189SArnaldo Carvalho de Melo break;
616df561f66SGustavo A. R. Silva fallthrough;
617b84a2189SArnaldo Carvalho de Melo case CCID3_FBACK_PERIODIC:
618996ccf49SGerrit Renker delta = ktime_us_delta(now, hc->rx_tstamp_last_feedback);
619410e27a4SGerrit Renker if (delta <= 0)
62074174fe5SEric Dumazet delta = 1;
621996ccf49SGerrit Renker hc->rx_x_recv = scaled_div32(hc->rx_bytes_recv, delta);
6227c657876SArnaldo Carvalho de Melo break;
623b84a2189SArnaldo Carvalho de Melo default:
6247c657876SArnaldo Carvalho de Melo return;
6257c657876SArnaldo Carvalho de Melo }
6267c657876SArnaldo Carvalho de Melo
6270ce4e70fSEric Dumazet ccid3_pr_debug("Interval %lldusec, X_recv=%u, 1/p=%u\n", delta,
628996ccf49SGerrit Renker hc->rx_x_recv, hc->rx_pinv);
6297c657876SArnaldo Carvalho de Melo
630996ccf49SGerrit Renker hc->rx_tstamp_last_feedback = now;
631996ccf49SGerrit Renker hc->rx_last_counter = dccp_hdr(skb)->dccph_ccval;
632996ccf49SGerrit Renker hc->rx_bytes_recv = 0;
633410e27a4SGerrit Renker
634410e27a4SGerrit Renker dp->dccps_hc_rx_insert_options = 1;
6357c657876SArnaldo Carvalho de Melo dccp_send_ack(sk);
6367c657876SArnaldo Carvalho de Melo }
6377c657876SArnaldo Carvalho de Melo
ccid3_hc_rx_insert_options(struct sock * sk,struct sk_buff * skb)6382d0817d1SArnaldo Carvalho de Melo static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb)
6397c657876SArnaldo Carvalho de Melo {
64051c22bb5SGerrit Renker const struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
64160fe62e7SAndrea Bittau __be32 x_recv, pinv;
6427c657876SArnaldo Carvalho de Melo
64359d203f9SArnaldo Carvalho de Melo if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN))
6442d0817d1SArnaldo Carvalho de Melo return 0;
6457c657876SArnaldo Carvalho de Melo
6464fded33bSArnaldo Carvalho de Melo if (dccp_packet_without_ack(skb))
6472d0817d1SArnaldo Carvalho de Melo return 0;
6484fded33bSArnaldo Carvalho de Melo
649996ccf49SGerrit Renker x_recv = htonl(hc->rx_x_recv);
650996ccf49SGerrit Renker pinv = htonl(hc->rx_pinv);
6512d0817d1SArnaldo Carvalho de Melo
652a7d13fbfSGerrit Renker if (dccp_insert_option(skb, TFRC_OPT_LOSS_EVENT_RATE,
6532d0817d1SArnaldo Carvalho de Melo &pinv, sizeof(pinv)) ||
654a7d13fbfSGerrit Renker dccp_insert_option(skb, TFRC_OPT_RECEIVE_RATE,
6552d0817d1SArnaldo Carvalho de Melo &x_recv, sizeof(x_recv)))
6562d0817d1SArnaldo Carvalho de Melo return -1;
6572d0817d1SArnaldo Carvalho de Melo
6582d0817d1SArnaldo Carvalho de Melo return 0;
6597c657876SArnaldo Carvalho de Melo }
6607c657876SArnaldo Carvalho de Melo
661aa1b1ff0SGerrit Renker /**
662aa1b1ff0SGerrit Renker * ccid3_first_li - Implements [RFC 5348, 6.3.1]
663*0b609b55SAndrew Lunn * @sk: socket to calculate loss interval for
664954c2db8SGerrit Renker *
665954c2db8SGerrit Renker * Determine the length of the first loss interval via inverse lookup.
666954c2db8SGerrit Renker * Assume that X_recv can be computed by the throughput equation
667954c2db8SGerrit Renker * s
668954c2db8SGerrit Renker * X_recv = --------
669954c2db8SGerrit Renker * R * fval
670954c2db8SGerrit Renker * Find some p such that f(p) = fval; return 1/p (scaled).
671954c2db8SGerrit Renker */
ccid3_first_li(struct sock * sk)672954c2db8SGerrit Renker static u32 ccid3_first_li(struct sock *sk)
673954c2db8SGerrit Renker {
674996ccf49SGerrit Renker struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
6750ce4e70fSEric Dumazet u32 x_recv, p;
6760ce4e70fSEric Dumazet s64 delta;
677954c2db8SGerrit Renker u64 fval;
678954c2db8SGerrit Renker
679996ccf49SGerrit Renker if (hc->rx_rtt == 0) {
680410e27a4SGerrit Renker DCCP_WARN("No RTT estimate available, using fallback RTT\n");
681996ccf49SGerrit Renker hc->rx_rtt = DCCP_FALLBACK_RTT;
682410e27a4SGerrit Renker }
683d20ed95fSGerrit Renker
6840ce4e70fSEric Dumazet delta = ktime_us_delta(ktime_get(), hc->rx_tstamp_last_feedback);
6850ce4e70fSEric Dumazet if (delta <= 0)
6860ce4e70fSEric Dumazet delta = 1;
687996ccf49SGerrit Renker x_recv = scaled_div32(hc->rx_bytes_recv, delta);
688410e27a4SGerrit Renker if (x_recv == 0) { /* would also trigger divide-by-zero */
689410e27a4SGerrit Renker DCCP_WARN("X_recv==0\n");
69067b67e36SGerrit Renker if (hc->rx_x_recv == 0) {
691410e27a4SGerrit Renker DCCP_BUG("stored value of X_recv is zero");
692410e27a4SGerrit Renker return ~0U;
693410e27a4SGerrit Renker }
69467b67e36SGerrit Renker x_recv = hc->rx_x_recv;
695410e27a4SGerrit Renker }
696954c2db8SGerrit Renker
697996ccf49SGerrit Renker fval = scaled_div(hc->rx_s, hc->rx_rtt);
698410e27a4SGerrit Renker fval = scaled_div32(fval, x_recv);
699954c2db8SGerrit Renker p = tfrc_calc_x_reverse_lookup(fval);
700954c2db8SGerrit Renker
701954c2db8SGerrit Renker ccid3_pr_debug("%s(%p), receive rate=%u bytes/s, implied "
702954c2db8SGerrit Renker "loss rate=%u\n", dccp_role(sk), sk, x_recv, p);
703954c2db8SGerrit Renker
704410e27a4SGerrit Renker return p == 0 ? ~0U : scaled_div(1, p);
705954c2db8SGerrit Renker }
706954c2db8SGerrit Renker
ccid3_hc_rx_packet_recv(struct sock * sk,struct sk_buff * skb)7077c657876SArnaldo Carvalho de Melo static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
7087c657876SArnaldo Carvalho de Melo {
709996ccf49SGerrit Renker struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
710410e27a4SGerrit Renker enum ccid3_fback_type do_feedback = CCID3_FBACK_NONE;
7115b5d0e70SGerrit Renker const u64 ndp = dccp_sk(sk)->dccps_options_received.dccpor_ndp;
712b84a2189SArnaldo Carvalho de Melo const bool is_data_packet = dccp_data_packet(skb);
7131f2333aeSArnaldo Carvalho de Melo
714996ccf49SGerrit Renker if (unlikely(hc->rx_state == TFRC_RSTATE_NO_DATA)) {
715410e27a4SGerrit Renker if (is_data_packet) {
716410e27a4SGerrit Renker const u32 payload = skb->len - dccp_hdr(skb)->dccph_doff * 4;
717410e27a4SGerrit Renker do_feedback = CCID3_FBACK_INITIAL;
718410e27a4SGerrit Renker ccid3_hc_rx_set_state(sk, TFRC_RSTATE_DATA);
719996ccf49SGerrit Renker hc->rx_s = payload;
720410e27a4SGerrit Renker /*
721388d5e99SGerrit Renker * Not necessary to update rx_bytes_recv here,
722410e27a4SGerrit Renker * since X_recv = 0 for the first feedback packet (cf.
723410e27a4SGerrit Renker * RFC 3448, 6.3) -- gerrit
724410e27a4SGerrit Renker */
725410e27a4SGerrit Renker }
726410e27a4SGerrit Renker goto update_records;
727410e27a4SGerrit Renker }
728410e27a4SGerrit Renker
729996ccf49SGerrit Renker if (tfrc_rx_hist_duplicate(&hc->rx_hist, skb))
730410e27a4SGerrit Renker return; /* done receiving */
731410e27a4SGerrit Renker
732410e27a4SGerrit Renker if (is_data_packet) {
733410e27a4SGerrit Renker const u32 payload = skb->len - dccp_hdr(skb)->dccph_doff * 4;
734410e27a4SGerrit Renker /*
735410e27a4SGerrit Renker * Update moving-average of s and the sum of received payload bytes
736410e27a4SGerrit Renker */
737996ccf49SGerrit Renker hc->rx_s = tfrc_ewma(hc->rx_s, payload, 9);
738996ccf49SGerrit Renker hc->rx_bytes_recv += payload;
739410e27a4SGerrit Renker }
740410e27a4SGerrit Renker
741d20ed95fSGerrit Renker /*
742d20ed95fSGerrit Renker * Perform loss detection and handle pending losses
743d20ed95fSGerrit Renker */
744996ccf49SGerrit Renker if (tfrc_rx_handle_loss(&hc->rx_hist, &hc->rx_li_hist,
745410e27a4SGerrit Renker skb, ndp, ccid3_first_li, sk)) {
746410e27a4SGerrit Renker do_feedback = CCID3_FBACK_PARAM_CHANGE;
747410e27a4SGerrit Renker goto done_receiving;
748410e27a4SGerrit Renker }
749410e27a4SGerrit Renker
750996ccf49SGerrit Renker if (tfrc_rx_hist_loss_pending(&hc->rx_hist))
751410e27a4SGerrit Renker return; /* done receiving */
752410e27a4SGerrit Renker
75388e97a93SGerrit Renker /*
754410e27a4SGerrit Renker * Handle data packets: RTT sampling and monitoring p
75588e97a93SGerrit Renker */
756410e27a4SGerrit Renker if (unlikely(!is_data_packet))
757410e27a4SGerrit Renker goto update_records;
758410e27a4SGerrit Renker
759996ccf49SGerrit Renker if (!tfrc_lh_is_initialised(&hc->rx_li_hist)) {
760996ccf49SGerrit Renker const u32 sample = tfrc_rx_hist_sample_rtt(&hc->rx_hist, skb);
761410e27a4SGerrit Renker /*
762410e27a4SGerrit Renker * Empty loss history: no loss so far, hence p stays 0.
763410e27a4SGerrit Renker * Sample RTT values, since an RTT estimate is required for the
764410e27a4SGerrit Renker * computation of p when the first loss occurs; RFC 3448, 6.3.1.
765410e27a4SGerrit Renker */
766410e27a4SGerrit Renker if (sample != 0)
767996ccf49SGerrit Renker hc->rx_rtt = tfrc_ewma(hc->rx_rtt, sample, 9);
768410e27a4SGerrit Renker
769996ccf49SGerrit Renker } else if (tfrc_lh_update_i_mean(&hc->rx_li_hist, skb)) {
770410e27a4SGerrit Renker /*
771410e27a4SGerrit Renker * Step (3) of [RFC 3448, 6.1]: Recompute I_mean and, if I_mean
772410e27a4SGerrit Renker * has decreased (resp. p has increased), send feedback now.
773410e27a4SGerrit Renker */
774410e27a4SGerrit Renker do_feedback = CCID3_FBACK_PARAM_CHANGE;
775410e27a4SGerrit Renker }
776410e27a4SGerrit Renker
777b84a2189SArnaldo Carvalho de Melo /*
778b84a2189SArnaldo Carvalho de Melo * Check if the periodic once-per-RTT feedback is due; RFC 4342, 10.3
779b84a2189SArnaldo Carvalho de Melo */
780996ccf49SGerrit Renker if (SUB16(dccp_hdr(skb)->dccph_ccval, hc->rx_last_counter) > 3)
781410e27a4SGerrit Renker do_feedback = CCID3_FBACK_PERIODIC;
782410e27a4SGerrit Renker
783410e27a4SGerrit Renker update_records:
784996ccf49SGerrit Renker tfrc_rx_hist_add_packet(&hc->rx_hist, skb, ndp);
785410e27a4SGerrit Renker
786410e27a4SGerrit Renker done_receiving:
787410e27a4SGerrit Renker if (do_feedback)
788410e27a4SGerrit Renker ccid3_hc_rx_send_feedback(sk, skb, do_feedback);
7897c657876SArnaldo Carvalho de Melo }
7907c657876SArnaldo Carvalho de Melo
ccid3_hc_rx_init(struct ccid * ccid,struct sock * sk)79191f0ebf7SArnaldo Carvalho de Melo static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk)
7927c657876SArnaldo Carvalho de Melo {
793996ccf49SGerrit Renker struct ccid3_hc_rx_sock *hc = ccid_priv(ccid);
7947c657876SArnaldo Carvalho de Melo
795996ccf49SGerrit Renker hc->rx_state = TFRC_RSTATE_NO_DATA;
796996ccf49SGerrit Renker tfrc_lh_init(&hc->rx_li_hist);
797996ccf49SGerrit Renker return tfrc_rx_hist_alloc(&hc->rx_hist);
7987c657876SArnaldo Carvalho de Melo }
7997c657876SArnaldo Carvalho de Melo
ccid3_hc_rx_exit(struct sock * sk)8007c657876SArnaldo Carvalho de Melo static void ccid3_hc_rx_exit(struct sock *sk)
8017c657876SArnaldo Carvalho de Melo {
802996ccf49SGerrit Renker struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
8037c657876SArnaldo Carvalho de Melo
804996ccf49SGerrit Renker tfrc_rx_hist_purge(&hc->rx_hist);
805996ccf49SGerrit Renker tfrc_lh_cleanup(&hc->rx_li_hist);
8067c657876SArnaldo Carvalho de Melo }
8077c657876SArnaldo Carvalho de Melo
ccid3_hc_rx_get_info(struct sock * sk,struct tcp_info * info)8082babe1f6SArnaldo Carvalho de Melo static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info)
8092babe1f6SArnaldo Carvalho de Melo {
81051c22bb5SGerrit Renker info->tcpi_ca_state = ccid3_hc_rx_sk(sk)->rx_state;
8112babe1f6SArnaldo Carvalho de Melo info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
81251c22bb5SGerrit Renker info->tcpi_rcv_rtt = ccid3_hc_rx_sk(sk)->rx_rtt;
8132babe1f6SArnaldo Carvalho de Melo }
8142babe1f6SArnaldo Carvalho de Melo
ccid3_hc_rx_getsockopt(struct sock * sk,const int optname,int len,u32 __user * optval,int __user * optlen)81588f964dbSArnaldo Carvalho de Melo static int ccid3_hc_rx_getsockopt(struct sock *sk, const int optname, int len,
81688f964dbSArnaldo Carvalho de Melo u32 __user *optval, int __user *optlen)
81788f964dbSArnaldo Carvalho de Melo {
81851c22bb5SGerrit Renker const struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
8198e138e79SGerrit Renker struct tfrc_rx_info rx_info;
82088f964dbSArnaldo Carvalho de Melo const void *val;
82188f964dbSArnaldo Carvalho de Melo
82288f964dbSArnaldo Carvalho de Melo switch (optname) {
82388f964dbSArnaldo Carvalho de Melo case DCCP_SOCKOPT_CCID_RX_INFO:
8248e138e79SGerrit Renker if (len < sizeof(rx_info))
82588f964dbSArnaldo Carvalho de Melo return -EINVAL;
826996ccf49SGerrit Renker rx_info.tfrcrx_x_recv = hc->rx_x_recv;
827996ccf49SGerrit Renker rx_info.tfrcrx_rtt = hc->rx_rtt;
828792e6d33SGerrit Renker rx_info.tfrcrx_p = tfrc_invert_loss_event_rate(hc->rx_pinv);
8298e138e79SGerrit Renker len = sizeof(rx_info);
8308e138e79SGerrit Renker val = &rx_info;
83188f964dbSArnaldo Carvalho de Melo break;
83288f964dbSArnaldo Carvalho de Melo default:
83388f964dbSArnaldo Carvalho de Melo return -ENOPROTOOPT;
83488f964dbSArnaldo Carvalho de Melo }
83588f964dbSArnaldo Carvalho de Melo
83688f964dbSArnaldo Carvalho de Melo if (put_user(len, optlen) || copy_to_user(optval, val, len))
83788f964dbSArnaldo Carvalho de Melo return -EFAULT;
83888f964dbSArnaldo Carvalho de Melo
83988f964dbSArnaldo Carvalho de Melo return 0;
84088f964dbSArnaldo Carvalho de Melo }
84188f964dbSArnaldo Carvalho de Melo
842ddebc973SGerrit Renker struct ccid_operations ccid3_ops = {
8433dd9a7c3SIan McDonald .ccid_id = DCCPC_CCID3,
84484a97b0aSGerrit Renker .ccid_name = "TCP-Friendly Rate Control",
84591f0ebf7SArnaldo Carvalho de Melo .ccid_hc_tx_obj_size = sizeof(struct ccid3_hc_tx_sock),
8467c657876SArnaldo Carvalho de Melo .ccid_hc_tx_init = ccid3_hc_tx_init,
8477c657876SArnaldo Carvalho de Melo .ccid_hc_tx_exit = ccid3_hc_tx_exit,
8487c657876SArnaldo Carvalho de Melo .ccid_hc_tx_send_packet = ccid3_hc_tx_send_packet,
8497c657876SArnaldo Carvalho de Melo .ccid_hc_tx_packet_sent = ccid3_hc_tx_packet_sent,
8507c657876SArnaldo Carvalho de Melo .ccid_hc_tx_packet_recv = ccid3_hc_tx_packet_recv,
8517c657876SArnaldo Carvalho de Melo .ccid_hc_tx_parse_options = ccid3_hc_tx_parse_options,
85291f0ebf7SArnaldo Carvalho de Melo .ccid_hc_rx_obj_size = sizeof(struct ccid3_hc_rx_sock),
8537c657876SArnaldo Carvalho de Melo .ccid_hc_rx_init = ccid3_hc_rx_init,
8547c657876SArnaldo Carvalho de Melo .ccid_hc_rx_exit = ccid3_hc_rx_exit,
8557c657876SArnaldo Carvalho de Melo .ccid_hc_rx_insert_options = ccid3_hc_rx_insert_options,
8567c657876SArnaldo Carvalho de Melo .ccid_hc_rx_packet_recv = ccid3_hc_rx_packet_recv,
8572babe1f6SArnaldo Carvalho de Melo .ccid_hc_rx_get_info = ccid3_hc_rx_get_info,
8582babe1f6SArnaldo Carvalho de Melo .ccid_hc_tx_get_info = ccid3_hc_tx_get_info,
85988f964dbSArnaldo Carvalho de Melo .ccid_hc_rx_getsockopt = ccid3_hc_rx_getsockopt,
86088f964dbSArnaldo Carvalho de Melo .ccid_hc_tx_getsockopt = ccid3_hc_tx_getsockopt,
8617c657876SArnaldo Carvalho de Melo };
8627c657876SArnaldo Carvalho de Melo
86356724aa4SGerrit Renker #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
86443264991SGerrit Renker module_param(ccid3_debug, bool, 0644);
865ddebc973SGerrit Renker MODULE_PARM_DESC(ccid3_debug, "Enable CCID-3 debug messages");
86656724aa4SGerrit Renker #endif
867