/* * net/dccp/ccids/ccid3.c * * Copyright (c) 2005 The University of Waikato, Hamilton, New Zealand. * Copyright (c) 2005-6 Ian McDonald * * An implementation of the DCCP protocol * * This code has been developed by the University of Waikato WAND * research group. For further information please see http://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 . * * Copyright (c) 2005 Arnaldo Carvalho de Melo * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include "../ccid.h" #include "../dccp.h" #include "lib/packet_history.h" #include "lib/loss_interval.h" #include "lib/tfrc.h" #include "ccid3.h" /* * Reason for maths here is to avoid 32 bit overflow when a is big. * With this we get close to the limit. */ static u32 usecs_div(const u32 a, const u32 b) { const u32 div = a < (UINT_MAX / (USEC_PER_SEC / 10)) ? 10 : a < (UINT_MAX / (USEC_PER_SEC / 50)) ? 50 : a < (UINT_MAX / (USEC_PER_SEC / 100)) ? 100 : a < (UINT_MAX / (USEC_PER_SEC / 500)) ? 500 : a < (UINT_MAX / (USEC_PER_SEC / 1000)) ? 1000 : a < (UINT_MAX / (USEC_PER_SEC / 5000)) ? 5000 : a < (UINT_MAX / (USEC_PER_SEC / 10000)) ? 10000 : a < (UINT_MAX / (USEC_PER_SEC / 50000)) ? 50000 : 100000; const u32 tmp = a * (USEC_PER_SEC / div); return (b >= 2 * div) ? tmp / (b / div) : tmp; } #ifdef CONFIG_IP_DCCP_CCID3_DEBUG static int ccid3_debug; #define ccid3_pr_debug(format, a...) DCCP_PR_DEBUG(ccid3_debug, format, ##a) #else #define ccid3_pr_debug(format, a...) #endif static struct dccp_tx_hist *ccid3_tx_hist; static struct dccp_rx_hist *ccid3_rx_hist; static struct dccp_li_hist *ccid3_li_hist; #ifdef CONFIG_IP_DCCP_CCID3_DEBUG static const char *ccid3_tx_state_name(enum ccid3_hc_tx_states state) { static char *ccid3_state_names[] = { [TFRC_SSTATE_NO_SENT] = "NO_SENT", [TFRC_SSTATE_NO_FBACK] = "NO_FBACK", [TFRC_SSTATE_FBACK] = "FBACK", [TFRC_SSTATE_TERM] = "TERM", }; 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 *hctx = ccid3_hc_tx_sk(sk); enum ccid3_hc_tx_states oldstate = hctx->ccid3hctx_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); hctx->ccid3hctx_state = state; } /* * Recalculate scheduled nominal send time t_nom, inter-packet interval * t_ipi, and delta value. Should be called after each change to X. */ static inline void ccid3_update_send_time(struct ccid3_hc_tx_sock *hctx) { timeval_sub_usecs(&hctx->ccid3hctx_t_nom, hctx->ccid3hctx_t_ipi); /* Calculate new t_ipi (inter packet interval) by t_ipi = s / X_inst */ hctx->ccid3hctx_t_ipi = usecs_div(hctx->ccid3hctx_s, hctx->ccid3hctx_x); /* Update nominal send time with regard to the new t_ipi */ timeval_add_usecs(&hctx->ccid3hctx_t_nom, hctx->ccid3hctx_t_ipi); /* Calculate new delta by delta = min(t_ipi / 2, t_gran / 2) */ hctx->ccid3hctx_delta = min_t(u32, hctx->ccid3hctx_t_ipi / 2, TFRC_OPSYS_HALF_TIME_GRAN); } /* * Update X by * If (p > 0) * x_calc = calcX(s, R, p); * X = max(min(X_calc, 2 * X_recv), s / t_mbi); * Else * If (now - tld >= R) * X = max(min(2 * X, 2 * X_recv), s / R); * tld = now; */ static void ccid3_hc_tx_update_x(struct sock *sk) { struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); const __u32 old_x = hctx->ccid3hctx_x; /* To avoid large error in calcX */ if (hctx->ccid3hctx_p >= TFRC_SMALLEST_P) { hctx->ccid3hctx_x_calc = tfrc_calc_x(hctx->ccid3hctx_s, hctx->ccid3hctx_rtt, hctx->ccid3hctx_p); hctx->ccid3hctx_x = max_t(u32, min_t(u32, hctx->ccid3hctx_x_calc, 2 * hctx->ccid3hctx_x_recv), (hctx->ccid3hctx_s / TFRC_MAX_BACK_OFF_TIME)); } else { struct timeval now; dccp_timestamp(sk, &now); if (timeval_delta(&now, &hctx->ccid3hctx_t_ld) >= hctx->ccid3hctx_rtt) { hctx->ccid3hctx_x = max_t(u32, min_t(u32, hctx->ccid3hctx_x_recv, hctx->ccid3hctx_x) * 2, usecs_div(hctx->ccid3hctx_s, hctx->ccid3hctx_rtt)); hctx->ccid3hctx_t_ld = now; } } if (hctx->ccid3hctx_x != old_x) ccid3_update_send_time(hctx); } /* * Track the mean packet size `s' (cf. RFC 4342, 5.3 and RFC 3448, 4.1) * @len: DCCP packet payload size in bytes */ static inline void ccid3_hc_tx_update_s(struct ccid3_hc_tx_sock *hctx, int len) { if (unlikely(len == 0)) ccid3_pr_debug("Packet payload length is 0 - not updating\n"); else hctx->ccid3hctx_s = hctx->ccid3hctx_s == 0 ? len : (9 * hctx->ccid3hctx_s + len) / 10; /* * Note: We could do a potential optimisation here - when `s' changes, * recalculate sending rate and consequently t_ipi, t_delta, and * t_now. This is however non-standard, and the benefits are not * clear, so it is currently left out. */ } static void ccid3_hc_tx_no_feedback_timer(unsigned long data) { struct sock *sk = (struct sock *)data; struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(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, sk=%p, state=%s\n", dccp_role(sk), sk, ccid3_tx_state_name(hctx->ccid3hctx_state)); switch (hctx->ccid3hctx_state) { case TFRC_SSTATE_NO_FBACK: /* Halve send rate */ hctx->ccid3hctx_x /= 2; if (hctx->ccid3hctx_x < (hctx->ccid3hctx_s / TFRC_MAX_BACK_OFF_TIME)) hctx->ccid3hctx_x = (hctx->ccid3hctx_s / TFRC_MAX_BACK_OFF_TIME); ccid3_pr_debug("%s, sk=%p, state=%s, updated tx rate to %d " "bytes/s\n", dccp_role(sk), sk, ccid3_tx_state_name(hctx->ccid3hctx_state), hctx->ccid3hctx_x); /* The value of R is still undefined and so we can not recompute * the timout value. Keep initial value as per [RFC 4342, 5]. */ t_nfb = TFRC_INITIAL_TIMEOUT; ccid3_update_send_time(hctx); break; case TFRC_SSTATE_FBACK: /* * Check if IDLE since last timeout and recv rate is less than * 4 packets per RTT */ if (!hctx->ccid3hctx_idle || (hctx->ccid3hctx_x_recv >= 4 * usecs_div(hctx->ccid3hctx_s, hctx->ccid3hctx_rtt))) { ccid3_pr_debug("%s, sk=%p, state=%s, not idle\n", dccp_role(sk), sk, ccid3_tx_state_name(hctx->ccid3hctx_state)); /* Halve sending rate */ /* If (X_calc > 2 * X_recv) * X_recv = max(X_recv / 2, s / (2 * t_mbi)); * Else * X_recv = X_calc / 4; */ BUG_ON(hctx->ccid3hctx_p >= TFRC_SMALLEST_P && hctx->ccid3hctx_x_calc == 0); /* check also if p is zero -> x_calc is infinity? */ if (hctx->ccid3hctx_p < TFRC_SMALLEST_P || hctx->ccid3hctx_x_calc > 2 * hctx->ccid3hctx_x_recv) hctx->ccid3hctx_x_recv = max_t(u32, hctx->ccid3hctx_x_recv / 2, hctx->ccid3hctx_s / (2 * TFRC_MAX_BACK_OFF_TIME)); else hctx->ccid3hctx_x_recv = hctx->ccid3hctx_x_calc / 4; /* Update sending rate */ ccid3_hc_tx_update_x(sk); } /* * Schedule no feedback timer to expire in * max(4 * R, 2 * s/X) = max(4 * R, 2 * t_ipi) */ t_nfb = max(4 * hctx->ccid3hctx_rtt, 2 * hctx->ccid3hctx_t_ipi); break; case TFRC_SSTATE_NO_SENT: DCCP_BUG("Illegal %s state NO_SENT, sk=%p", dccp_role(sk), sk); /* fall through */ case TFRC_SSTATE_TERM: goto out; } hctx->ccid3hctx_idle = 1; restart_timer: sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer, jiffies + usecs_to_jiffies(t_nfb)); out: bh_unlock_sock(sk); sock_put(sk); } /* * returns * > 0: delay (in msecs) that should pass before actually sending * = 0: can send immediately * < 0: error condition; do not send packet */ static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb, int len) { struct dccp_sock *dp = dccp_sk(sk); struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); struct dccp_tx_hist_entry *new_packet; struct timeval now; long delay; BUG_ON(hctx == NULL); /* * 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(len == 0)) return -EBADMSG; /* See if last packet allocated was not sent */ new_packet = dccp_tx_hist_head(&hctx->ccid3hctx_hist); if (new_packet == NULL || new_packet->dccphtx_sent) { new_packet = dccp_tx_hist_entry_new(ccid3_tx_hist, SLAB_ATOMIC); if (unlikely(new_packet == NULL)) { DCCP_WARN("%s, sk=%p, not enough mem to add to history," "send refused\n", dccp_role(sk), sk); return -ENOBUFS; } dccp_tx_hist_add_entry(&hctx->ccid3hctx_hist, new_packet); } dccp_timestamp(sk, &now); switch (hctx->ccid3hctx_state) { case TFRC_SSTATE_NO_SENT: sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer, jiffies + usecs_to_jiffies(TFRC_INITIAL_TIMEOUT)); hctx->ccid3hctx_last_win_count = 0; hctx->ccid3hctx_t_last_win_count = now; ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK); /* Set initial sending rate to 1 packet per second */ ccid3_hc_tx_update_s(hctx, len); hctx->ccid3hctx_x = hctx->ccid3hctx_s; /* First timeout, according to [RFC 3448, 4.2], is 1 second */ hctx->ccid3hctx_t_ipi = USEC_PER_SEC; /* Initial delta: minimum of 0.5 sec and t_gran/2 */ hctx->ccid3hctx_delta = TFRC_OPSYS_HALF_TIME_GRAN; /* Set t_0 for initial packet */ hctx->ccid3hctx_t_nom = now; break; case TFRC_SSTATE_NO_FBACK: case TFRC_SSTATE_FBACK: delay = timeval_delta(&hctx->ccid3hctx_t_nom, &now); /* * Scheduling of packet transmissions [RFC 3448, 4.6] * * if (t_now > t_nom - delta) * // send the packet now * else * // send the packet in (t_nom - t_now) milliseconds. */ if (delay >= hctx->ccid3hctx_delta) return delay / 1000L; break; case TFRC_SSTATE_TERM: DCCP_BUG("Illegal %s state TERM, sk=%p", dccp_role(sk), sk); return -EINVAL; } /* prepare to send now (add options etc.) */ dp->dccps_hc_tx_insert_options = 1; new_packet->dccphtx_ccval = DCCP_SKB_CB(skb)->dccpd_ccval = hctx->ccid3hctx_last_win_count; timeval_add_usecs(&hctx->ccid3hctx_t_nom, hctx->ccid3hctx_t_ipi); return 0; } static void ccid3_hc_tx_packet_sent(struct sock *sk, int more, int len) { const struct dccp_sock *dp = dccp_sk(sk); struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); struct timeval now; BUG_ON(hctx == NULL); dccp_timestamp(sk, &now); /* check if we have sent a data packet */ if (len > 0) { unsigned long quarter_rtt; struct dccp_tx_hist_entry *packet; ccid3_hc_tx_update_s(hctx, len); packet = dccp_tx_hist_head(&hctx->ccid3hctx_hist); if (unlikely(packet == NULL)) { DCCP_WARN("packet doesn't exist in history!\n"); return; } if (unlikely(packet->dccphtx_sent)) { DCCP_WARN("no unsent packet in history!\n"); return; } packet->dccphtx_tstamp = now; packet->dccphtx_seqno = dp->dccps_gss; /* * Check if win_count have changed * Algorithm in "8.1. Window Counter Value" in RFC 4342. */ quarter_rtt = timeval_delta(&now, &hctx->ccid3hctx_t_last_win_count); if (likely(hctx->ccid3hctx_rtt > 8)) quarter_rtt /= hctx->ccid3hctx_rtt / 4; if (quarter_rtt > 0) { hctx->ccid3hctx_t_last_win_count = now; hctx->ccid3hctx_last_win_count = (hctx->ccid3hctx_last_win_count + min_t(unsigned long, quarter_rtt, 5)) % 16; ccid3_pr_debug("%s, sk=%p, window changed from " "%u to %u!\n", dccp_role(sk), sk, packet->dccphtx_ccval, hctx->ccid3hctx_last_win_count); } hctx->ccid3hctx_idle = 0; packet->dccphtx_rtt = hctx->ccid3hctx_rtt; packet->dccphtx_sent = 1; } else ccid3_pr_debug("%s, sk=%p, seqno=%llu NOT inserted!\n", dccp_role(sk), sk, dp->dccps_gss); } static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb) { 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; struct dccp_tx_hist_entry *packet; struct timeval now; unsigned long t_nfb; u32 t_elapsed; u32 pinv; u32 x_recv; u32 r_sample; BUG_ON(hctx == NULL); /* 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; opt_recv = &hctx->ccid3hctx_options_received; t_elapsed = dp->dccps_options_received.dccpor_elapsed_time * 10; x_recv = opt_recv->ccid3or_receive_rate; pinv = opt_recv->ccid3or_loss_event_rate; switch (hctx->ccid3hctx_state) { case TFRC_SSTATE_NO_FBACK: case TFRC_SSTATE_FBACK: /* Calculate new round trip sample by * R_sample = (now - t_recvdata) - t_delay */ /* get t_recvdata from history */ packet = dccp_tx_hist_find_entry(&hctx->ccid3hctx_hist, DCCP_SKB_CB(skb)->dccpd_ack_seq); if (unlikely(packet == NULL)) { DCCP_WARN("%s, sk=%p, seqno %llu(%s) does't exist " "in history!\n", dccp_role(sk), sk, (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq, dccp_packet_name(DCCP_SKB_CB(skb)->dccpd_type)); return; } /* Update RTT */ dccp_timestamp(sk, &now); r_sample = timeval_delta(&now, &packet->dccphtx_tstamp); if (unlikely(r_sample <= t_elapsed)) DCCP_WARN("r_sample=%uus,t_elapsed=%uus\n", r_sample, t_elapsed); else r_sample -= t_elapsed; /* Update RTT estimate by * If (No feedback recv) * R = R_sample; * Else * R = q * R + (1 - q) * R_sample; * * q is a constant, RFC 3448 recomments 0.9 */ if (hctx->ccid3hctx_state == TFRC_SSTATE_NO_FBACK) { ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK); hctx->ccid3hctx_rtt = r_sample; } else hctx->ccid3hctx_rtt = (hctx->ccid3hctx_rtt * 9) / 10 + r_sample / 10; ccid3_pr_debug("%s, sk=%p, New RTT estimate=%uus, " "r_sample=%us\n", dccp_role(sk), sk, hctx->ccid3hctx_rtt, r_sample); /* Update receive rate */ hctx->ccid3hctx_x_recv = x_recv;/* X_recv in bytes per sec */ /* Update loss event rate */ if (pinv == ~0 || pinv == 0) hctx->ccid3hctx_p = 0; else { hctx->ccid3hctx_p = 1000000 / pinv; if (hctx->ccid3hctx_p < TFRC_SMALLEST_P) { hctx->ccid3hctx_p = TFRC_SMALLEST_P; ccid3_pr_debug("%s, sk=%p, Smallest p used!\n", dccp_role(sk), sk); } } /* unschedule no feedback timer */ sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer); /* Update sending rate (and likely t_ipi, t_nom, and delta) */ ccid3_hc_tx_update_x(sk); /* remove all packets older than the one acked from history */ dccp_tx_hist_purge_older(ccid3_tx_hist, &hctx->ccid3hctx_hist, packet); /* * 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. We use the alternative variant of * [RFC 3448, 3.1] which sets the upper bound of t_rto to one * second, as it is suggested for TCP (see RFC 2988, 2.4). */ hctx->ccid3hctx_t_rto = max_t(u32, 4 * hctx->ccid3hctx_rtt, USEC_PER_SEC ); /* * Schedule no feedback timer to expire in * max(4 * R, 2 * s/X) = max(4 * R, 2 * t_ipi) */ t_nfb = max(4 * hctx->ccid3hctx_rtt, 2 * hctx->ccid3hctx_t_ipi); ccid3_pr_debug("%s, sk=%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)); /* set idle flag */ hctx->ccid3hctx_idle = 1; break; case TFRC_SSTATE_NO_SENT: DCCP_WARN("Illegal ACK received - no packet has been sent\n"); /* fall through */ case TFRC_SSTATE_TERM: /* ignore feedback when closing */ break; } } static int ccid3_hc_tx_insert_options(struct sock *sk, struct sk_buff *skb) { const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); BUG_ON(hctx == NULL); if (sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN) DCCP_SKB_CB(skb)->dccpd_ccval = hctx->ccid3hctx_last_win_count; return 0; } 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; BUG_ON(hctx == NULL); 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, sk=%p, invalid len %d " "for TFRC_OPT_LOSS_EVENT_RATE\n", dccp_role(sk), sk, len); rc = -EINVAL; } else { opt_recv->ccid3or_loss_event_rate = ntohl(*(__be32 *)value); ccid3_pr_debug("%s, sk=%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, sk=%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, sk=%p, invalid len %d " "for TFRC_OPT_RECEIVE_RATE\n", dccp_role(sk), sk, len); rc = -EINVAL; } else { opt_recv->ccid3or_receive_rate = ntohl(*(__be32 *)value); ccid3_pr_debug("%s, sk=%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_s = 0; hctx->ccid3hctx_state = TFRC_SSTATE_NO_SENT; INIT_LIST_HEAD(&hctx->ccid3hctx_hist); hctx->ccid3hctx_no_feedback_timer.function = ccid3_hc_tx_no_feedback_timer; hctx->ccid3hctx_no_feedback_timer.data = (unsigned long)sk; init_timer(&hctx->ccid3hctx_no_feedback_timer); return 0; } static void ccid3_hc_tx_exit(struct sock *sk) { struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); BUG_ON(hctx == NULL); ccid3_hc_tx_set_state(sk, TFRC_SSTATE_TERM); sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer); /* Empty packet history */ dccp_tx_hist_purge(ccid3_tx_hist, &hctx->ccid3hctx_hist); } /* * RX Half Connection methods */ #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 inline void ccid3_hc_rx_update_s(struct ccid3_hc_rx_sock *hcrx, int len) { if (unlikely(len == 0)) /* don't update on empty packets (e.g. ACKs) */ ccid3_pr_debug("Packet payload length is 0 - not updating\n"); else hcrx->ccid3hcrx_s = hcrx->ccid3hcrx_s == 0 ? len : (9 * hcrx->ccid3hcrx_s + len) / 10; } static void ccid3_hc_rx_send_feedback(struct sock *sk) { struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); struct dccp_sock *dp = dccp_sk(sk); struct dccp_rx_hist_entry *packet; struct timeval now; ccid3_pr_debug("%s, sk=%p\n", dccp_role(sk), sk); dccp_timestamp(sk, &now); switch (hcrx->ccid3hcrx_state) { case TFRC_RSTATE_NO_DATA: hcrx->ccid3hcrx_x_recv = 0; break; case TFRC_RSTATE_DATA: { const u32 delta = timeval_delta(&now, &hcrx->ccid3hcrx_tstamp_last_feedback); hcrx->ccid3hcrx_x_recv = usecs_div(hcrx->ccid3hcrx_bytes_recv, delta); } break; case TFRC_RSTATE_TERM: DCCP_BUG("Illegal %s state TERM, sk=%p", dccp_role(sk), sk); return; } packet = dccp_rx_hist_find_data_packet(&hcrx->ccid3hcrx_hist); if (unlikely(packet == NULL)) { DCCP_WARN("%s, sk=%p, no data packet in history!\n", dccp_role(sk), sk); return; } hcrx->ccid3hcrx_tstamp_last_feedback = now; hcrx->ccid3hcrx_ccval_last_counter = packet->dccphrx_ccval; hcrx->ccid3hcrx_bytes_recv = 0; /* Convert to multiples of 10us */ hcrx->ccid3hcrx_elapsed_time = timeval_delta(&now, &packet->dccphrx_tstamp) / 10; if (hcrx->ccid3hcrx_p == 0) hcrx->ccid3hcrx_pinv = ~0; else hcrx->ccid3hcrx_pinv = 1000000 / hcrx->ccid3hcrx_p; 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 = ccid3_hc_rx_sk(sk); __be32 x_recv, pinv; BUG_ON(hcrx == NULL); if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN)) return 0; DCCP_SKB_CB(skb)->dccpd_ccval = hcrx->ccid3hcrx_ccval_last_counter; if (dccp_packet_without_ack(skb)) return 0; x_recv = htonl(hcrx->ccid3hcrx_x_recv); pinv = htonl(hcrx->ccid3hcrx_pinv); if ((hcrx->ccid3hcrx_elapsed_time != 0 && dccp_insert_option_elapsed_time(sk, skb, hcrx->ccid3hcrx_elapsed_time)) || dccp_insert_option_timestamp(sk, skb) || 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; } /* calculate first loss interval * * returns estimated loss interval in usecs */ static u32 ccid3_hc_rx_calc_first_li(struct sock *sk) { struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); struct dccp_rx_hist_entry *entry, *next, *tail = NULL; u32 rtt, delta, x_recv, fval, p, tmp2; struct timeval tstamp = { 0, }; int interval = 0; int win_count = 0; int step = 0; u64 tmp1; list_for_each_entry_safe(entry, next, &hcrx->ccid3hcrx_hist, dccphrx_node) { if (dccp_rx_hist_entry_data_packet(entry)) { tail = entry; switch (step) { case 0: tstamp = entry->dccphrx_tstamp; win_count = entry->dccphrx_ccval; step = 1; break; case 1: interval = win_count - entry->dccphrx_ccval; if (interval < 0) interval += TFRC_WIN_COUNT_LIMIT; if (interval > 4) goto found; break; } } } if (unlikely(step == 0)) { DCCP_WARN("%s, sk=%p, packet history has no data packets!\n", dccp_role(sk), sk); return ~0; } if (unlikely(interval == 0)) { DCCP_WARN("%s, sk=%p, Could not find a win_count interval > 0." "Defaulting to 1\n", dccp_role(sk), sk); interval = 1; } found: if (!tail) { DCCP_CRIT("tail is null\n"); return ~0; } rtt = timeval_delta(&tstamp, &tail->dccphrx_tstamp) * 4 / interval; ccid3_pr_debug("%s, sk=%p, approximated RTT to %uus\n", dccp_role(sk), sk, rtt); if (rtt == 0) { DCCP_WARN("RTT==0, setting to 1\n"); rtt = 1; } dccp_timestamp(sk, &tstamp); delta = timeval_delta(&tstamp, &hcrx->ccid3hcrx_tstamp_last_feedback); x_recv = usecs_div(hcrx->ccid3hcrx_bytes_recv, delta); if (x_recv == 0) x_recv = hcrx->ccid3hcrx_x_recv; tmp1 = (u64)x_recv * (u64)rtt; do_div(tmp1,10000000); tmp2 = (u32)tmp1; if (!tmp2) { DCCP_CRIT("tmp2 = 0, x_recv = %u, rtt =%u\n", x_recv, rtt); return ~0; } fval = (hcrx->ccid3hcrx_s * 100000) / tmp2; /* do not alter order above or you will get overflow on 32 bit */ p = tfrc_calc_x_reverse_lookup(fval); ccid3_pr_debug("%s, sk=%p, receive rate=%u bytes/s, implied " "loss rate=%u\n", dccp_role(sk), sk, x_recv, p); if (p == 0) return ~0; else return 1000000 / p; } static void ccid3_hc_rx_update_li(struct sock *sk, u64 seq_loss, u8 win_loss) { struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); struct dccp_li_hist_entry *head; u64 seq_temp; if (list_empty(&hcrx->ccid3hcrx_li_hist)) { if (!dccp_li_hist_interval_new(ccid3_li_hist, &hcrx->ccid3hcrx_li_hist, seq_loss, win_loss)) return; head = list_entry(hcrx->ccid3hcrx_li_hist.next, struct dccp_li_hist_entry, dccplih_node); head->dccplih_interval = ccid3_hc_rx_calc_first_li(sk); } else { struct dccp_li_hist_entry *entry; struct list_head *tail; head = list_entry(hcrx->ccid3hcrx_li_hist.next, struct dccp_li_hist_entry, dccplih_node); /* FIXME win count check removed as was wrong */ /* should make this check with receive history */ /* and compare there as per section 10.2 of RFC4342 */ /* new loss event detected */ /* calculate last interval length */ seq_temp = dccp_delta_seqno(head->dccplih_seqno, seq_loss); entry = dccp_li_hist_entry_new(ccid3_li_hist, SLAB_ATOMIC); if (entry == NULL) { DCCP_BUG("out of memory - can not allocate entry"); return; } list_add(&entry->dccplih_node, &hcrx->ccid3hcrx_li_hist); tail = hcrx->ccid3hcrx_li_hist.prev; list_del(tail); kmem_cache_free(ccid3_li_hist->dccplih_slab, tail); /* Create the newest interval */ entry->dccplih_seqno = seq_loss; entry->dccplih_interval = seq_temp; entry->dccplih_win_count = win_loss; } } static int ccid3_hc_rx_detect_loss(struct sock *sk, struct dccp_rx_hist_entry *packet) { struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); struct dccp_rx_hist_entry *rx_hist = dccp_rx_hist_head(&hcrx->ccid3hcrx_hist); u64 seqno = packet->dccphrx_seqno; u64 tmp_seqno; int loss = 0; u8 ccval; tmp_seqno = hcrx->ccid3hcrx_seqno_nonloss; if (!rx_hist || follows48(packet->dccphrx_seqno, hcrx->ccid3hcrx_seqno_nonloss)) { hcrx->ccid3hcrx_seqno_nonloss = seqno; hcrx->ccid3hcrx_ccval_nonloss = packet->dccphrx_ccval; goto detect_out; } while (dccp_delta_seqno(hcrx->ccid3hcrx_seqno_nonloss, seqno) > TFRC_RECV_NUM_LATE_LOSS) { loss = 1; ccid3_hc_rx_update_li(sk, hcrx->ccid3hcrx_seqno_nonloss, hcrx->ccid3hcrx_ccval_nonloss); tmp_seqno = hcrx->ccid3hcrx_seqno_nonloss; dccp_inc_seqno(&tmp_seqno); hcrx->ccid3hcrx_seqno_nonloss = tmp_seqno; dccp_inc_seqno(&tmp_seqno); while (dccp_rx_hist_find_entry(&hcrx->ccid3hcrx_hist, tmp_seqno, &ccval)) { hcrx->ccid3hcrx_seqno_nonloss = tmp_seqno; hcrx->ccid3hcrx_ccval_nonloss = ccval; dccp_inc_seqno(&tmp_seqno); } } /* FIXME - this code could be simplified with above while */ /* but works at moment */ if (follows48(packet->dccphrx_seqno, hcrx->ccid3hcrx_seqno_nonloss)) { hcrx->ccid3hcrx_seqno_nonloss = seqno; hcrx->ccid3hcrx_ccval_nonloss = packet->dccphrx_ccval; } detect_out: dccp_rx_hist_add_packet(ccid3_rx_hist, &hcrx->ccid3hcrx_hist, &hcrx->ccid3hcrx_li_hist, packet, hcrx->ccid3hcrx_seqno_nonloss); return loss; } 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); const struct dccp_options_received *opt_recv; struct dccp_rx_hist_entry *packet; struct timeval now; u32 p_prev, rtt_prev, r_sample, t_elapsed; int loss, payload_size; BUG_ON(hcrx == NULL); opt_recv = &dccp_sk(sk)->dccps_options_received; switch (DCCP_SKB_CB(skb)->dccpd_type) { case DCCP_PKT_ACK: if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA) return; case DCCP_PKT_DATAACK: if (opt_recv->dccpor_timestamp_echo == 0) break; rtt_prev = hcrx->ccid3hcrx_rtt; dccp_timestamp(sk, &now); timeval_sub_usecs(&now, opt_recv->dccpor_timestamp_echo * 10); r_sample = timeval_usecs(&now); t_elapsed = opt_recv->dccpor_elapsed_time * 10; if (unlikely(r_sample <= t_elapsed)) DCCP_WARN("r_sample=%uus, t_elapsed=%uus\n", r_sample, t_elapsed); else r_sample -= t_elapsed; if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA) hcrx->ccid3hcrx_rtt = r_sample; else hcrx->ccid3hcrx_rtt = (hcrx->ccid3hcrx_rtt * 9) / 10 + r_sample / 10; if (rtt_prev != hcrx->ccid3hcrx_rtt) ccid3_pr_debug("%s, New RTT=%uus, elapsed time=%u\n", dccp_role(sk), hcrx->ccid3hcrx_rtt, opt_recv->dccpor_elapsed_time); break; case DCCP_PKT_DATA: break; default: /* We're not interested in other packet types, move along */ return; } packet = dccp_rx_hist_entry_new(ccid3_rx_hist, sk, opt_recv->dccpor_ndp, skb, SLAB_ATOMIC); if (unlikely(packet == NULL)) { DCCP_WARN("%s, sk=%p, Not enough mem to add rx packet " "to history, consider it lost!\n", dccp_role(sk), sk); return; } loss = ccid3_hc_rx_detect_loss(sk, packet); if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK) return; payload_size = skb->len - dccp_hdr(skb)->dccph_doff * 4; ccid3_hc_rx_update_s(hcrx, payload_size); switch (hcrx->ccid3hcrx_state) { case TFRC_RSTATE_NO_DATA: ccid3_pr_debug("%s, sk=%p(%s), skb=%p, sending initial " "feedback\n", dccp_role(sk), sk, dccp_state_name(sk->sk_state), skb); ccid3_hc_rx_send_feedback(sk); ccid3_hc_rx_set_state(sk, TFRC_RSTATE_DATA); return; case TFRC_RSTATE_DATA: hcrx->ccid3hcrx_bytes_recv += payload_size; if (loss) break; dccp_timestamp(sk, &now); if (timeval_delta(&now, &hcrx->ccid3hcrx_tstamp_last_ack) >= hcrx->ccid3hcrx_rtt) { hcrx->ccid3hcrx_tstamp_last_ack = now; ccid3_hc_rx_send_feedback(sk); } return; case TFRC_RSTATE_TERM: DCCP_BUG("Illegal %s state TERM, sk=%p", dccp_role(sk), sk); return; } /* Dealing with packet loss */ ccid3_pr_debug("%s, sk=%p(%s), data loss! Reacting...\n", dccp_role(sk), sk, dccp_state_name(sk->sk_state)); p_prev = hcrx->ccid3hcrx_p; /* Calculate loss event rate */ if (!list_empty(&hcrx->ccid3hcrx_li_hist)) { u32 i_mean = dccp_li_hist_calc_i_mean(&hcrx->ccid3hcrx_li_hist); /* Scaling up by 1000000 as fixed decimal */ if (i_mean != 0) hcrx->ccid3hcrx_p = 1000000 / i_mean; } else DCCP_BUG("empty loss history"); if (hcrx->ccid3hcrx_p > p_prev) { ccid3_hc_rx_send_feedback(sk); return; } } static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk) { struct ccid3_hc_rx_sock *hcrx = ccid_priv(ccid); ccid3_pr_debug("%s, sk=%p\n", dccp_role(sk), sk); hcrx->ccid3hcrx_state = TFRC_RSTATE_NO_DATA; INIT_LIST_HEAD(&hcrx->ccid3hcrx_hist); INIT_LIST_HEAD(&hcrx->ccid3hcrx_li_hist); dccp_timestamp(sk, &hcrx->ccid3hcrx_tstamp_last_ack); hcrx->ccid3hcrx_tstamp_last_feedback = hcrx->ccid3hcrx_tstamp_last_ack; hcrx->ccid3hcrx_s = 0; hcrx->ccid3hcrx_rtt = 5000; /* XXX 5ms for now... */ return 0; } static void ccid3_hc_rx_exit(struct sock *sk) { struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); BUG_ON(hcrx == NULL); ccid3_hc_rx_set_state(sk, TFRC_RSTATE_TERM); /* Empty packet history */ dccp_rx_hist_purge(ccid3_rx_hist, &hcrx->ccid3hcrx_hist); /* Empty loss interval history */ dccp_li_hist_purge(ccid3_li_hist, &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 = ccid3_hc_rx_sk(sk); /* Listen socks doesn't have a private CCID block */ if (sk->sk_state == DCCP_LISTEN) return; BUG_ON(hcrx == NULL); info->tcpi_ca_state = hcrx->ccid3hcrx_state; info->tcpi_options |= TCPI_OPT_TIMESTAMPS; info->tcpi_rcv_rtt = hcrx->ccid3hcrx_rtt; } static void ccid3_hc_tx_get_info(struct sock *sk, struct tcp_info *info) { const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); /* Listen socks doesn't have a private CCID block */ if (sk->sk_state == DCCP_LISTEN) return; BUG_ON(hctx == NULL); info->tcpi_rto = hctx->ccid3hctx_t_rto; info->tcpi_rtt = hctx->ccid3hctx_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 = ccid3_hc_rx_sk(sk); const void *val; /* Listen socks doesn't have a private CCID block */ if (sk->sk_state == DCCP_LISTEN) return -EINVAL; switch (optname) { case DCCP_SOCKOPT_CCID_RX_INFO: if (len < sizeof(hcrx->ccid3hcrx_tfrc)) return -EINVAL; len = sizeof(hcrx->ccid3hcrx_tfrc); val = &hcrx->ccid3hcrx_tfrc; break; default: return -ENOPROTOOPT; } if (put_user(len, optlen) || copy_to_user(optval, val, len)) return -EFAULT; return 0; } 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 = ccid3_hc_tx_sk(sk); const void *val; /* Listen socks doesn't have a private CCID block */ if (sk->sk_state == DCCP_LISTEN) return -EINVAL; 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; } static struct ccid_operations ccid3 = { .ccid_id = DCCPC_CCID3, .ccid_name = "ccid3", .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_insert_options = ccid3_hc_tx_insert_options, .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, int, 0444); MODULE_PARM_DESC(ccid3_debug, "Enable debug messages"); #endif static __init int ccid3_module_init(void) { int rc = -ENOBUFS; ccid3_rx_hist = dccp_rx_hist_new("ccid3"); if (ccid3_rx_hist == NULL) goto out; ccid3_tx_hist = dccp_tx_hist_new("ccid3"); if (ccid3_tx_hist == NULL) goto out_free_rx; ccid3_li_hist = dccp_li_hist_new("ccid3"); if (ccid3_li_hist == NULL) goto out_free_tx; rc = ccid_register(&ccid3); if (rc != 0) goto out_free_loss_interval_history; out: return rc; out_free_loss_interval_history: dccp_li_hist_delete(ccid3_li_hist); ccid3_li_hist = NULL; out_free_tx: dccp_tx_hist_delete(ccid3_tx_hist); ccid3_tx_hist = NULL; out_free_rx: dccp_rx_hist_delete(ccid3_rx_hist); ccid3_rx_hist = NULL; goto out; } module_init(ccid3_module_init); static __exit void ccid3_module_exit(void) { ccid_unregister(&ccid3); if (ccid3_tx_hist != NULL) { dccp_tx_hist_delete(ccid3_tx_hist); ccid3_tx_hist = NULL; } if (ccid3_rx_hist != NULL) { dccp_rx_hist_delete(ccid3_rx_hist); ccid3_rx_hist = NULL; } if (ccid3_li_hist != NULL) { dccp_li_hist_delete(ccid3_li_hist); ccid3_li_hist = NULL; } } module_exit(ccid3_module_exit); MODULE_AUTHOR("Ian McDonald , " "Arnaldo Carvalho de Melo "); MODULE_DESCRIPTION("DCCP TFRC CCID3 CCID"); MODULE_LICENSE("GPL"); MODULE_ALIAS("net-dccp-ccid-3");