diff options
Diffstat (limited to 'net/dccp/ccids/ccid3.c')
| -rw-r--r-- | net/dccp/ccids/ccid3.c | 866 |
1 files changed, 0 insertions, 866 deletions
diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c deleted file mode 100644 index f349d16dd8f6..000000000000 --- a/net/dccp/ccids/ccid3.c +++ /dev/null @@ -1,866 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0-or-later -/* - * Copyright (c) 2007 The University of Aberdeen, Scotland, UK - * Copyright (c) 2005-7 The University of Waikato, Hamilton, New Zealand. - * Copyright (c) 2005-7 Ian McDonald <ian.mcdonald@jandi.co.nz> - * - * An implementation of the DCCP protocol - * - * This code has been developed by the University of Waikato WAND - * research group. For further information please see https://www.wand.net.nz/ - * - * This code also uses code from Lulea University, rereleased as GPL by its - * authors: - * Copyright (c) 2003 Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon - * - * Changes to meet Linux coding standards, to make it meet latest ccid3 draft - * and to make it work as a loadable module in the DCCP stack written by - * Arnaldo Carvalho de Melo <acme@conectiva.com.br>. - * - * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br> - */ -#include "../dccp.h" -#include "ccid3.h" - -#include <linux/unaligned.h> - -#ifdef CONFIG_IP_DCCP_CCID3_DEBUG -static bool ccid3_debug; -#define ccid3_pr_debug(format, a...) DCCP_PR_DEBUG(ccid3_debug, format, ##a) -#else -#define ccid3_pr_debug(format, a...) -#endif - -/* - * Transmitter Half-Connection Routines - */ -#ifdef CONFIG_IP_DCCP_CCID3_DEBUG -static const char *ccid3_tx_state_name(enum ccid3_hc_tx_states state) -{ - static const char *const ccid3_state_names[] = { - [TFRC_SSTATE_NO_SENT] = "NO_SENT", - [TFRC_SSTATE_NO_FBACK] = "NO_FBACK", - [TFRC_SSTATE_FBACK] = "FBACK", - }; - - return ccid3_state_names[state]; -} -#endif - -static void ccid3_hc_tx_set_state(struct sock *sk, - enum ccid3_hc_tx_states state) -{ - struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk); - enum ccid3_hc_tx_states oldstate = hc->tx_state; - - ccid3_pr_debug("%s(%p) %-8.8s -> %s\n", - dccp_role(sk), sk, ccid3_tx_state_name(oldstate), - ccid3_tx_state_name(state)); - WARN_ON(state == oldstate); - hc->tx_state = state; -} - -/* - * Compute the initial sending rate X_init in the manner of RFC 3390: - * - * X_init = min(4 * s, max(2 * s, 4380 bytes)) / RTT - * - * Note that RFC 3390 uses MSS, RFC 4342 refers to RFC 3390, and rfc3448bis - * (rev-02) clarifies the use of RFC 3390 with regard to the above formula. - * For consistency with other parts of the code, X_init is scaled by 2^6. - */ -static inline u64 rfc3390_initial_rate(struct sock *sk) -{ - const struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk); - const __u32 w_init = clamp_t(__u32, 4380U, 2 * hc->tx_s, 4 * hc->tx_s); - - return scaled_div(w_init << 6, hc->tx_rtt); -} - -/** - * ccid3_update_send_interval - Calculate new t_ipi = s / X_inst - * @hc: socket to have the send interval updated - * - * This respects the granularity of X_inst (64 * bytes/second). - */ -static void ccid3_update_send_interval(struct ccid3_hc_tx_sock *hc) -{ - hc->tx_t_ipi = scaled_div32(((u64)hc->tx_s) << 6, hc->tx_x); - - DCCP_BUG_ON(hc->tx_t_ipi == 0); - ccid3_pr_debug("t_ipi=%u, s=%u, X=%u\n", hc->tx_t_ipi, - hc->tx_s, (unsigned int)(hc->tx_x >> 6)); -} - -static u32 ccid3_hc_tx_idle_rtt(struct ccid3_hc_tx_sock *hc, ktime_t now) -{ - u32 delta = ktime_us_delta(now, hc->tx_t_last_win_count); - - return delta / hc->tx_rtt; -} - -/** - * ccid3_hc_tx_update_x - Update allowed sending rate X - * @sk: socket to be updated - * @stamp: most recent time if available - can be left NULL. - * - * This function tracks draft rfc3448bis, check there for latest details. - * - * Note: X and X_recv are both stored in units of 64 * bytes/second, to support - * fine-grained resolution of sending rates. This requires scaling by 2^6 - * throughout the code. Only X_calc is unscaled (in bytes/second). - * - */ -static void ccid3_hc_tx_update_x(struct sock *sk, ktime_t *stamp) -{ - struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk); - __u64 min_rate = 2 * hc->tx_x_recv; - const __u64 old_x = hc->tx_x; - ktime_t now = stamp ? *stamp : ktime_get_real(); - - /* - * Handle IDLE periods: do not reduce below RFC3390 initial sending rate - * when idling [RFC 4342, 5.1]. Definition of idling is from rfc3448bis: - * a sender is idle if it has not sent anything over a 2-RTT-period. - * For consistency with X and X_recv, min_rate is also scaled by 2^6. - */ - if (ccid3_hc_tx_idle_rtt(hc, now) >= 2) { - min_rate = rfc3390_initial_rate(sk); - min_rate = max(min_rate, 2 * hc->tx_x_recv); - } - - if (hc->tx_p > 0) { - - hc->tx_x = min(((__u64)hc->tx_x_calc) << 6, min_rate); - hc->tx_x = max(hc->tx_x, (((__u64)hc->tx_s) << 6) / TFRC_T_MBI); - - } else if (ktime_us_delta(now, hc->tx_t_ld) - (s64)hc->tx_rtt >= 0) { - - hc->tx_x = min(2 * hc->tx_x, min_rate); - hc->tx_x = max(hc->tx_x, - scaled_div(((__u64)hc->tx_s) << 6, hc->tx_rtt)); - hc->tx_t_ld = now; - } - - if (hc->tx_x != old_x) { - ccid3_pr_debug("X_prev=%u, X_now=%u, X_calc=%u, " - "X_recv=%u\n", (unsigned int)(old_x >> 6), - (unsigned int)(hc->tx_x >> 6), hc->tx_x_calc, - (unsigned int)(hc->tx_x_recv >> 6)); - - ccid3_update_send_interval(hc); - } -} - -/** - * ccid3_hc_tx_update_s - Track the mean packet size `s' - * @hc: socket to be updated - * @len: DCCP packet payload size in bytes - * - * cf. RFC 4342, 5.3 and RFC 3448, 4.1 - */ -static inline void ccid3_hc_tx_update_s(struct ccid3_hc_tx_sock *hc, int len) -{ - const u16 old_s = hc->tx_s; - - hc->tx_s = tfrc_ewma(hc->tx_s, len, 9); - - if (hc->tx_s != old_s) - ccid3_update_send_interval(hc); -} - -/* - * Update Window Counter using the algorithm from [RFC 4342, 8.1]. - * As elsewhere, RTT > 0 is assumed by using dccp_sample_rtt(). - */ -static inline void ccid3_hc_tx_update_win_count(struct ccid3_hc_tx_sock *hc, - ktime_t now) -{ - u32 delta = ktime_us_delta(now, hc->tx_t_last_win_count), - quarter_rtts = (4 * delta) / hc->tx_rtt; - - if (quarter_rtts > 0) { - hc->tx_t_last_win_count = now; - hc->tx_last_win_count += min(quarter_rtts, 5U); - hc->tx_last_win_count &= 0xF; /* mod 16 */ - } -} - -static void ccid3_hc_tx_no_feedback_timer(struct timer_list *t) -{ - struct ccid3_hc_tx_sock *hc = from_timer(hc, t, tx_no_feedback_timer); - struct sock *sk = hc->sk; - unsigned long t_nfb = USEC_PER_SEC / 5; - - bh_lock_sock(sk); - if (sock_owned_by_user(sk)) { - /* Try again later. */ - /* XXX: set some sensible MIB */ - goto restart_timer; - } - - ccid3_pr_debug("%s(%p, state=%s) - entry\n", dccp_role(sk), sk, - ccid3_tx_state_name(hc->tx_state)); - - /* Ignore and do not restart after leaving the established state */ - if ((1 << sk->sk_state) & ~(DCCPF_OPEN | DCCPF_PARTOPEN)) - goto out; - - /* Reset feedback state to "no feedback received" */ - if (hc->tx_state == TFRC_SSTATE_FBACK) - ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK); - - /* - * Determine new allowed sending rate X as per draft rfc3448bis-00, 4.4 - * RTO is 0 if and only if no feedback has been received yet. - */ - if (hc->tx_t_rto == 0 || hc->tx_p == 0) { - - /* halve send rate directly */ - hc->tx_x = max(hc->tx_x / 2, - (((__u64)hc->tx_s) << 6) / TFRC_T_MBI); - ccid3_update_send_interval(hc); - } else { - /* - * Modify the cached value of X_recv - * - * If (X_calc > 2 * X_recv) - * X_recv = max(X_recv / 2, s / (2 * t_mbi)); - * Else - * X_recv = X_calc / 4; - * - * Note that X_recv is scaled by 2^6 while X_calc is not - */ - if (hc->tx_x_calc > (hc->tx_x_recv >> 5)) - hc->tx_x_recv = - max(hc->tx_x_recv / 2, - (((__u64)hc->tx_s) << 6) / (2*TFRC_T_MBI)); - else { - hc->tx_x_recv = hc->tx_x_calc; - hc->tx_x_recv <<= 4; - } - ccid3_hc_tx_update_x(sk, NULL); - } - ccid3_pr_debug("Reduced X to %llu/64 bytes/sec\n", - (unsigned long long)hc->tx_x); - - /* - * Set new timeout for the nofeedback timer. - * See comments in packet_recv() regarding the value of t_RTO. - */ - if (unlikely(hc->tx_t_rto == 0)) /* no feedback received yet */ - t_nfb = TFRC_INITIAL_TIMEOUT; - else - t_nfb = max(hc->tx_t_rto, 2 * hc->tx_t_ipi); - -restart_timer: - sk_reset_timer(sk, &hc->tx_no_feedback_timer, - jiffies + usecs_to_jiffies(t_nfb)); -out: - bh_unlock_sock(sk); - sock_put(sk); -} - -/** - * ccid3_hc_tx_send_packet - Delay-based dequeueing of TX packets - * @sk: socket to send packet from - * @skb: next packet candidate to send on @sk - * - * This function uses the convention of ccid_packet_dequeue_eval() and - * returns a millisecond-delay value between 0 and t_mbi = 64000 msec. - */ -static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb) -{ - struct dccp_sock *dp = dccp_sk(sk); - struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk); - ktime_t now = ktime_get_real(); - s64 delay; - - /* - * This function is called only for Data and DataAck packets. Sending - * zero-sized Data(Ack)s is theoretically possible, but for congestion - * control this case is pathological - ignore it. - */ - if (unlikely(skb->len == 0)) - return -EBADMSG; - - if (hc->tx_state == TFRC_SSTATE_NO_SENT) { - sk_reset_timer(sk, &hc->tx_no_feedback_timer, (jiffies + - usecs_to_jiffies(TFRC_INITIAL_TIMEOUT))); - hc->tx_last_win_count = 0; - hc->tx_t_last_win_count = now; - - /* Set t_0 for initial packet */ - hc->tx_t_nom = now; - - hc->tx_s = skb->len; - - /* - * Use initial RTT sample when available: recommended by erratum - * to RFC 4342. This implements the initialisation procedure of - * draft rfc3448bis, section 4.2. Remember, X is scaled by 2^6. - */ - if (dp->dccps_syn_rtt) { - ccid3_pr_debug("SYN RTT = %uus\n", dp->dccps_syn_rtt); - hc->tx_rtt = dp->dccps_syn_rtt; - hc->tx_x = rfc3390_initial_rate(sk); - hc->tx_t_ld = now; - } else { - /* - * Sender does not have RTT sample: - * - set fallback RTT (RFC 4340, 3.4) since a RTT value - * is needed in several parts (e.g. window counter); - * - set sending rate X_pps = 1pps as per RFC 3448, 4.2. - */ - hc->tx_rtt = DCCP_FALLBACK_RTT; - hc->tx_x = hc->tx_s; - hc->tx_x <<= 6; - } - ccid3_update_send_interval(hc); - - ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK); - - } else { - delay = ktime_us_delta(hc->tx_t_nom, now); - ccid3_pr_debug("delay=%ld\n", (long)delay); - /* - * Scheduling of packet transmissions (RFC 5348, 8.3) - * - * if (t_now > t_nom - delta) - * // send the packet now - * else - * // send the packet in (t_nom - t_now) milliseconds. - */ - if (delay >= TFRC_T_DELTA) - return (u32)delay / USEC_PER_MSEC; - - ccid3_hc_tx_update_win_count(hc, now); - } - - /* prepare to send now (add options etc.) */ - dp->dccps_hc_tx_insert_options = 1; - DCCP_SKB_CB(skb)->dccpd_ccval = hc->tx_last_win_count; - - /* set the nominal send time for the next following packet */ - hc->tx_t_nom = ktime_add_us(hc->tx_t_nom, hc->tx_t_ipi); - return CCID_PACKET_SEND_AT_ONCE; -} - -static void ccid3_hc_tx_packet_sent(struct sock *sk, unsigned int len) -{ - struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk); - - ccid3_hc_tx_update_s(hc, len); - - if (tfrc_tx_hist_add(&hc->tx_hist, dccp_sk(sk)->dccps_gss)) - DCCP_CRIT("packet history - out of memory!"); -} - -static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb) -{ - struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk); - struct tfrc_tx_hist_entry *acked; - ktime_t now; - unsigned long t_nfb; - u32 r_sample; - - /* we are only interested in ACKs */ - if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK || - DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_DATAACK)) - return; - /* - * Locate the acknowledged packet in the TX history. - * - * Returning "entry not found" here can for instance happen when - * - the host has not sent out anything (e.g. a passive server), - * - the Ack is outdated (packet with higher Ack number was received), - * - it is a bogus Ack (for a packet not sent on this connection). - */ - acked = tfrc_tx_hist_find_entry(hc->tx_hist, dccp_hdr_ack_seq(skb)); - if (acked == NULL) - return; - /* For the sake of RTT sampling, ignore/remove all older entries */ - tfrc_tx_hist_purge(&acked->next); - - /* Update the moving average for the RTT estimate (RFC 3448, 4.3) */ - now = ktime_get_real(); - r_sample = dccp_sample_rtt(sk, ktime_us_delta(now, acked->stamp)); - hc->tx_rtt = tfrc_ewma(hc->tx_rtt, r_sample, 9); - - /* - * Update allowed sending rate X as per draft rfc3448bis-00, 4.2/3 - */ - if (hc->tx_state == TFRC_SSTATE_NO_FBACK) { - ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK); - - if (hc->tx_t_rto == 0) { - /* - * Initial feedback packet: Larger Initial Windows (4.2) - */ - hc->tx_x = rfc3390_initial_rate(sk); - hc->tx_t_ld = now; - - ccid3_update_send_interval(hc); - - goto done_computing_x; - } else if (hc->tx_p == 0) { - /* - * First feedback after nofeedback timer expiry (4.3) - */ - goto done_computing_x; - } - } - - /* Update sending rate (step 4 of [RFC 3448, 4.3]) */ - if (hc->tx_p > 0) - hc->tx_x_calc = tfrc_calc_x(hc->tx_s, hc->tx_rtt, hc->tx_p); - ccid3_hc_tx_update_x(sk, &now); - -done_computing_x: - 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, hc->tx_rtt, r_sample, - hc->tx_s, hc->tx_p, hc->tx_x_calc, - (unsigned int)(hc->tx_x_recv >> 6), - (unsigned int)(hc->tx_x >> 6)); - - /* unschedule no feedback timer */ - sk_stop_timer(sk, &hc->tx_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. In order to control - * rate halving on networks with very low RTTs (<= 1 ms), use per-route - * tunable RTAX_RTO_MIN value as the lower bound. - */ - hc->tx_t_rto = max_t(u32, 4 * hc->tx_rtt, - USEC_PER_SEC/HZ * tcp_rto_min(sk)); - /* - * Schedule no feedback timer to expire in - * max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi) - */ - t_nfb = max(hc->tx_t_rto, 2 * hc->tx_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, &hc->tx_no_feedback_timer, - jiffies + usecs_to_jiffies(t_nfb)); -} - -static int ccid3_hc_tx_parse_options(struct sock *sk, u8 packet_type, - u8 option, u8 *optval, u8 optlen) -{ - struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk); - __be32 opt_val; - - switch (option) { - case TFRC_OPT_RECEIVE_RATE: - case TFRC_OPT_LOSS_EVENT_RATE: - /* Must be ignored on Data packets, cf. RFC 4342 8.3 and 8.5 */ - if (packet_type == DCCP_PKT_DATA) - break; - if (unlikely(optlen != 4)) { - DCCP_WARN("%s(%p), invalid len %d for %u\n", - dccp_role(sk), sk, optlen, option); - return -EINVAL; - } - opt_val = ntohl(get_unaligned((__be32 *)optval)); - - if (option == TFRC_OPT_RECEIVE_RATE) { - /* Receive Rate is kept in units of 64 bytes/second */ - hc->tx_x_recv = opt_val; - hc->tx_x_recv <<= 6; - - ccid3_pr_debug("%s(%p), RECEIVE_RATE=%u\n", - dccp_role(sk), sk, opt_val); - } else { - /* Update the fixpoint Loss Event Rate fraction */ - hc->tx_p = tfrc_invert_loss_event_rate(opt_val); - - ccid3_pr_debug("%s(%p), LOSS_EVENT_RATE=%u\n", - dccp_role(sk), sk, opt_val); - } - } - return 0; -} - -static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk) -{ - struct ccid3_hc_tx_sock *hc = ccid_priv(ccid); - - hc->tx_state = TFRC_SSTATE_NO_SENT; - hc->tx_hist = NULL; - hc->sk = sk; - timer_setup(&hc->tx_no_feedback_timer, - ccid3_hc_tx_no_feedback_timer, 0); - return 0; -} - -static void ccid3_hc_tx_exit(struct sock *sk) -{ - struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk); - - sk_stop_timer(sk, &hc->tx_no_feedback_timer); - tfrc_tx_hist_purge(&hc->tx_hist); -} - -static void ccid3_hc_tx_get_info(struct sock *sk, struct tcp_info *info) -{ - info->tcpi_rto = ccid3_hc_tx_sk(sk)->tx_t_rto; - info->tcpi_rtt = ccid3_hc_tx_sk(sk)->tx_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 *hc = ccid3_hc_tx_sk(sk); - struct tfrc_tx_info tfrc; - const void *val; - - switch (optname) { - case DCCP_SOCKOPT_CCID_TX_INFO: - if (len < sizeof(tfrc)) - return -EINVAL; - memset(&tfrc, 0, sizeof(tfrc)); - tfrc.tfrctx_x = hc->tx_x; - tfrc.tfrctx_x_recv = hc->tx_x_recv; - tfrc.tfrctx_x_calc = hc->tx_x_calc; - tfrc.tfrctx_rtt = hc->tx_rtt; - tfrc.tfrctx_p = hc->tx_p; - tfrc.tfrctx_rto = hc->tx_t_rto; - tfrc.tfrctx_ipi = hc->tx_t_ipi; - len = sizeof(tfrc); - val = &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 const char *const ccid3_rx_state_names[] = { - [TFRC_RSTATE_NO_DATA] = "NO_DATA", - [TFRC_RSTATE_DATA] = "DATA", - }; - - 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 *hc = ccid3_hc_rx_sk(sk); - enum ccid3_hc_rx_states oldstate = hc->rx_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); - hc->rx_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 *hc = ccid3_hc_rx_sk(sk); - struct dccp_sock *dp = dccp_sk(sk); - ktime_t now = ktime_get(); - s64 delta = 0; - - switch (fbtype) { - case CCID3_FBACK_INITIAL: - hc->rx_x_recv = 0; - hc->rx_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 (hc->rx_x_recv > 0) - break; - fallthrough; - case CCID3_FBACK_PERIODIC: - delta = ktime_us_delta(now, hc->rx_tstamp_last_feedback); - if (delta <= 0) - delta = 1; - hc->rx_x_recv = scaled_div32(hc->rx_bytes_recv, delta); - break; - default: - return; - } - - ccid3_pr_debug("Interval %lldusec, X_recv=%u, 1/p=%u\n", delta, - hc->rx_x_recv, hc->rx_pinv); - - hc->rx_tstamp_last_feedback = now; - hc->rx_last_counter = dccp_hdr(skb)->dccph_ccval; - hc->rx_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 *hc = ccid3_hc_rx_sk(sk); - __be32 x_recv, pinv; - - if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN)) - return 0; - - if (dccp_packet_without_ack(skb)) - return 0; - - x_recv = htonl(hc->rx_x_recv); - pinv = htonl(hc->rx_pinv); - - if (dccp_insert_option(skb, TFRC_OPT_LOSS_EVENT_RATE, - &pinv, sizeof(pinv)) || - dccp_insert_option(skb, TFRC_OPT_RECEIVE_RATE, - &x_recv, sizeof(x_recv))) - return -1; - - return 0; -} - -/** - * ccid3_first_li - Implements [RFC 5348, 6.3.1] - * @sk: socket to calculate loss interval for - * - * 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 *hc = ccid3_hc_rx_sk(sk); - u32 x_recv, p; - s64 delta; - u64 fval; - - if (hc->rx_rtt == 0) { - DCCP_WARN("No RTT estimate available, using fallback RTT\n"); - hc->rx_rtt = DCCP_FALLBACK_RTT; - } - - delta = ktime_us_delta(ktime_get(), hc->rx_tstamp_last_feedback); - if (delta <= 0) - delta = 1; - x_recv = scaled_div32(hc->rx_bytes_recv, delta); - if (x_recv == 0) { /* would also trigger divide-by-zero */ - DCCP_WARN("X_recv==0\n"); - if (hc->rx_x_recv == 0) { - DCCP_BUG("stored value of X_recv is zero"); - return ~0U; - } - x_recv = hc->rx_x_recv; - } - - fval = scaled_div(hc->rx_s, hc->rx_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 *hc = ccid3_hc_rx_sk(sk); - enum ccid3_fback_type do_feedback = CCID3_FBACK_NONE; - const u64 ndp = dccp_sk(sk)->dccps_options_received.dccpor_ndp; - const bool is_data_packet = dccp_data_packet(skb); - - if (unlikely(hc->rx_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); - hc->rx_s = payload; - /* - * Not necessary to update rx_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(&hc->rx_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 - */ - hc->rx_s = tfrc_ewma(hc->rx_s, payload, 9); - hc->rx_bytes_recv += payload; - } - - /* - * Perform loss detection and handle pending losses - */ - if (tfrc_rx_handle_loss(&hc->rx_hist, &hc->rx_li_hist, - skb, ndp, ccid3_first_li, sk)) { - do_feedback = CCID3_FBACK_PARAM_CHANGE; - goto done_receiving; - } - - if (tfrc_rx_hist_loss_pending(&hc->rx_hist)) - return; /* done receiving */ - - /* - * Handle data packets: RTT sampling and monitoring p - */ - if (unlikely(!is_data_packet)) - goto update_records; - - if (!tfrc_lh_is_initialised(&hc->rx_li_hist)) { - const u32 sample = tfrc_rx_hist_sample_rtt(&hc->rx_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) - hc->rx_rtt = tfrc_ewma(hc->rx_rtt, sample, 9); - - } else if (tfrc_lh_update_i_mean(&hc->rx_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, hc->rx_last_counter) > 3) - do_feedback = CCID3_FBACK_PERIODIC; - -update_records: - tfrc_rx_hist_add_packet(&hc->rx_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 *hc = ccid_priv(ccid); - - hc->rx_state = TFRC_RSTATE_NO_DATA; - tfrc_lh_init(&hc->rx_li_hist); - return tfrc_rx_hist_alloc(&hc->rx_hist); -} - -static void ccid3_hc_rx_exit(struct sock *sk) -{ - struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk); - - tfrc_rx_hist_purge(&hc->rx_hist); - tfrc_lh_cleanup(&hc->rx_li_hist); -} - -static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info) -{ - info->tcpi_ca_state = ccid3_hc_rx_sk(sk)->rx_state; - info->tcpi_options |= TCPI_OPT_TIMESTAMPS; - info->tcpi_rcv_rtt = ccid3_hc_rx_sk(sk)->rx_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 *hc = ccid3_hc_rx_sk(sk); - struct tfrc_rx_info rx_info; - const void *val; - - switch (optname) { - case DCCP_SOCKOPT_CCID_RX_INFO: - if (len < sizeof(rx_info)) - return -EINVAL; - rx_info.tfrcrx_x_recv = hc->rx_x_recv; - rx_info.tfrcrx_rtt = hc->rx_rtt; - rx_info.tfrcrx_p = tfrc_invert_loss_event_rate(hc->rx_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; -} - -struct ccid_operations ccid3_ops = { - .ccid_id = DCCPC_CCID3, - .ccid_name = "TCP-Friendly Rate Control", - .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, 0644); -MODULE_PARM_DESC(ccid3_debug, "Enable CCID-3 debug messages"); -#endif |