diff options
Diffstat (limited to 'net/dccp/ccids/ccid3.c')
| -rw-r--r-- | net/dccp/ccids/ccid3.c | 1167 |
1 files changed, 456 insertions, 711 deletions
diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c index e91c2b9dc27..119c04317d4 100644 --- a/net/dccp/ccids/ccid3.c +++ b/net/dccp/ccids/ccid3.c @@ -1,6 +1,5 @@ /* - * net/dccp/ccids/ccid3.c - * + * 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> * @@ -33,34 +32,28 @@ * 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" +#include <asm/unaligned.h> + #ifdef CONFIG_IP_DCCP_CCID3_DEBUG -static int 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 -static struct dccp_tx_hist *ccid3_tx_hist; -static struct dccp_rx_hist *ccid3_rx_hist; - /* * Transmitter Half-Connection Routines */ #ifdef CONFIG_IP_DCCP_CCID3_DEBUG static const char *ccid3_tx_state_name(enum ccid3_hc_tx_states state) { - static char *ccid3_state_names[] = { + static const char *const 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]; @@ -70,151 +63,142 @@ static const char *ccid3_tx_state_name(enum ccid3_hc_tx_states state) 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; + 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); - hctx->ccid3hctx_state = state; + hc->tx_state = state; } /* - * Compute the initial sending rate X_init according to RFC 3390: - * w_init = min(4 * MSS, max(2 * MSS, 4380 bytes)) - * X_init = w_init / RTT + * 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 dccp_sock *dp = dccp_sk(sk); - const __u32 w_init = min(4 * dp->dccps_mss_cache, - max(2 * dp->dccps_mss_cache, 4380U)); + 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, ccid3_hc_tx_sk(sk)->ccid3hctx_rtt); + return scaled_div(w_init << 6, hc->tx_rtt); } -/* - * Recalculate t_ipi and delta (should be called whenever X changes) +/** + * ccid3_update_send_interval - Calculate new t_ipi = s / X_inst + * This respects the granularity of X_inst (64 * bytes/second). */ -static inline void ccid3_update_send_interval(struct ccid3_hc_tx_sock *hctx) +static void ccid3_update_send_interval(struct ccid3_hc_tx_sock *hc) { - /* Calculate new t_ipi = s / X_inst (X_inst is in 64 * bytes/second) */ - hctx->ccid3hctx_t_ipi = scaled_div32(((u64)hctx->ccid3hctx_s) << 6, - hctx->ccid3hctx_x); + hc->tx_t_ipi = scaled_div32(((u64)hc->tx_s) << 6, hc->tx_x); - /* 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); + 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)); +} - ccid3_pr_debug("t_ipi=%u, delta=%u, s=%u, X=%u\n", - hctx->ccid3hctx_t_ipi, hctx->ccid3hctx_delta, - hctx->ccid3hctx_s, (unsigned)(hctx->ccid3hctx_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; } -/* - * 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; + +/** + * ccid3_hc_tx_update_x - Update allowed sending rate X + * @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, struct timeval *now) - +static void ccid3_hc_tx_update_x(struct sock *sk, ktime_t *stamp) { - struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); - __u64 min_rate = 2 * hctx->ccid3hctx_x_recv; - const __u64 old_x = hctx->ccid3hctx_x; + 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]. See also draft-ietf-dccp-rfc3448bis. + * 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 (unlikely(hctx->ccid3hctx_idle)) { + if (ccid3_hc_tx_idle_rtt(hc, now) >= 2) { min_rate = rfc3390_initial_rate(sk); - min_rate = max(min_rate, 2 * hctx->ccid3hctx_x_recv); + min_rate = max(min_rate, 2 * hc->tx_x_recv); } - if (hctx->ccid3hctx_p > 0) { + if (hc->tx_p > 0) { - hctx->ccid3hctx_x = min(((__u64)hctx->ccid3hctx_x_calc) << 6, - min_rate); - hctx->ccid3hctx_x = max(hctx->ccid3hctx_x, - (((__u64)hctx->ccid3hctx_s) << 6) / - TFRC_T_MBI); + 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 (timeval_delta(now, &hctx->ccid3hctx_t_ld) - - (suseconds_t)hctx->ccid3hctx_rtt >= 0) { + } else if (ktime_us_delta(now, hc->tx_t_ld) - (s64)hc->tx_rtt >= 0) { - hctx->ccid3hctx_x = - max(min(2 * hctx->ccid3hctx_x, min_rate), - scaled_div(((__u64)hctx->ccid3hctx_s) << 6, - hctx->ccid3hctx_rtt)); - hctx->ccid3hctx_t_ld = *now; + 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 (hctx->ccid3hctx_x != old_x) { + if (hc->tx_x != old_x) { ccid3_pr_debug("X_prev=%u, X_now=%u, X_calc=%u, " - "X_recv=%u\n", (unsigned)(old_x >> 6), - (unsigned)(hctx->ccid3hctx_x >> 6), - hctx->ccid3hctx_x_calc, - (unsigned)(hctx->ccid3hctx_x_recv >> 6)); + "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(hctx); + ccid3_update_send_interval(hc); } } -/* - * Track the mean packet size `s' (cf. RFC 4342, 5.3 and RFC 3448, 4.1) +/** + * ccid3_hc_tx_update_s - Track the mean packet size `s' * @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 *hctx, int len) +static inline void ccid3_hc_tx_update_s(struct ccid3_hc_tx_sock *hc, int len) { - const u16 old_s = hctx->ccid3hctx_s; + const u16 old_s = hc->tx_s; - hctx->ccid3hctx_s = old_s == 0 ? len : (9 * old_s + len) / 10; + hc->tx_s = tfrc_ewma(hc->tx_s, len, 9); - if (hctx->ccid3hctx_s != old_s) - ccid3_update_send_interval(hctx); + if (hc->tx_s != old_s) + ccid3_update_send_interval(hc); } /* * Update Window Counter using the algorithm from [RFC 4342, 8.1]. - * The algorithm is not applicable if RTT < 4 microseconds. + * 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 *hctx, +static inline void ccid3_hc_tx_update_win_count(struct ccid3_hc_tx_sock *hc, ktime_t now) { - u32 quarter_rtts; - - if (unlikely(hctx->ccid3hctx_rtt < 4)) /* avoid divide-by-zero */ - return; - - quarter_rtts = ktime_us_delta(now, hctx->ccid3hctx_t_last_win_count); - quarter_rtts /= hctx->ccid3hctx_rtt / 4; + u32 delta = ktime_us_delta(now, hc->tx_t_last_win_count), + quarter_rtts = (4 * delta) / hc->tx_rtt; if (quarter_rtts > 0) { - hctx->ccid3hctx_t_last_win_count = now; - hctx->ccid3hctx_last_win_count += min_t(u32, quarter_rtts, 5); - hctx->ccid3hctx_last_win_count &= 0xF; /* mod 16 */ + 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(unsigned long data) { struct sock *sk = (struct sock *)data; - struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); - struct timeval now; + struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk); unsigned long t_nfb = USEC_PER_SEC / 5; bh_lock_sock(sk); @@ -224,93 +208,82 @@ static void ccid3_hc_tx_no_feedback_timer(unsigned long data) goto restart_timer; } - ccid3_pr_debug("%s(%p, state=%s) - entry \n", dccp_role(sk), sk, - ccid3_tx_state_name(hctx->ccid3hctx_state)); + ccid3_pr_debug("%s(%p, state=%s) - entry\n", dccp_role(sk), sk, + ccid3_tx_state_name(hc->tx_state)); - hctx->ccid3hctx_idle = 1; + /* Ignore and do not restart after leaving the established state */ + if ((1 << sk->sk_state) & ~(DCCPF_OPEN | DCCPF_PARTOPEN)) + goto out; - switch (hctx->ccid3hctx_state) { - case TFRC_SSTATE_NO_FBACK: - /* RFC 3448, 4.4: Halve send rate directly */ - hctx->ccid3hctx_x = max(hctx->ccid3hctx_x / 2, - (((__u64)hctx->ccid3hctx_s) << 6) / - TFRC_T_MBI); + /* Reset feedback state to "no feedback received" */ + if (hc->tx_state == TFRC_SSTATE_FBACK) + ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK); - ccid3_pr_debug("%s(%p, state=%s), updated tx rate to %u " - "bytes/s\n", dccp_role(sk), sk, - ccid3_tx_state_name(hctx->ccid3hctx_state), - (unsigned)(hctx->ccid3hctx_x >> 6)); - /* 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_interval(hctx); - break; - case TFRC_SSTATE_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 [RFC 3448, 4.4] + * Modify the cached value of X_recv * - * If (p == 0 || X_calc > 2 * 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 */ - BUG_ON(hctx->ccid3hctx_p && !hctx->ccid3hctx_x_calc); - - if (hctx->ccid3hctx_p == 0 || - (hctx->ccid3hctx_x_calc > (hctx->ccid3hctx_x_recv >> 5))) { - - hctx->ccid3hctx_x_recv = - max(hctx->ccid3hctx_x_recv / 2, - (((__u64)hctx->ccid3hctx_s) << 6) / - (2 * TFRC_T_MBI)); - - if (hctx->ccid3hctx_p == 0) - dccp_timestamp(sk, &now); - } else { - hctx->ccid3hctx_x_recv = hctx->ccid3hctx_x_calc; - hctx->ccid3hctx_x_recv <<= 4; + 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; } - /* Now recalculate X [RFC 3448, 4.3, step (4)] */ - ccid3_hc_tx_update_x(sk, &now); - /* - * Schedule no feedback timer to expire in - * max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi) - * See comments in packet_recv() regarding the value of t_RTO. - */ - t_nfb = max(hctx->ccid3hctx_t_rto, 2 * hctx->ccid3hctx_t_ipi); - break; - case TFRC_SSTATE_NO_SENT: - DCCP_BUG("%s(%p) - Illegal state NO_SENT", dccp_role(sk), sk); - /* fall through */ - case TFRC_SSTATE_TERM: - goto out; + 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, &hctx->ccid3hctx_no_feedback_timer, + sk_reset_timer(sk, &hc->tx_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 +/** + * ccid3_hc_tx_send_packet - Delay-based dequeueing of TX packets + * @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 *hctx = ccid3_hc_tx_sk(sk); + struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk); ktime_t now = ktime_get_real(); s64 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 @@ -319,18 +292,16 @@ static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb) if (unlikely(skb->len == 0)) return -EBADMSG; - 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; + 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 */ - hctx->ccid3hctx_t_nom = now; + hc->tx_t_nom = now; - hctx->ccid3hctx_s = skb->len; + hc->tx_s = skb->len; /* * Use initial RTT sample when available: recommended by erratum @@ -339,342 +310,241 @@ static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb) */ if (dp->dccps_syn_rtt) { ccid3_pr_debug("SYN RTT = %uus\n", dp->dccps_syn_rtt); - hctx->ccid3hctx_rtt = dp->dccps_syn_rtt; - hctx->ccid3hctx_x = rfc3390_initial_rate(sk); - hctx->ccid3hctx_t_ld = ktime_to_timeval(now); + 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: X = MSS/second */ - hctx->ccid3hctx_x = dp->dccps_mss_cache; - hctx->ccid3hctx_x <<= 6; + /* + * 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(hctx); + ccid3_update_send_interval(hc); ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK); - break; - case TFRC_SSTATE_NO_FBACK: - case TFRC_SSTATE_FBACK: - delay = ktime_us_delta(hctx->ccid3hctx_t_nom, now); + + } else { + delay = ktime_us_delta(hc->tx_t_nom, now); ccid3_pr_debug("delay=%ld\n", (long)delay); /* - * Scheduling of packet transmissions [RFC 3448, 4.6] + * 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 - (s64)hctx->ccid3hctx_delta >= 1000) - return (u32)delay / 1000L; + if (delay >= TFRC_T_DELTA) + return (u32)delay / USEC_PER_MSEC; - ccid3_hc_tx_update_win_count(hctx, now); - break; - case TFRC_SSTATE_TERM: - DCCP_BUG("%s(%p) - Illegal state TERM", dccp_role(sk), sk); - return -EINVAL; + 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 = hctx->ccid3hctx_last_win_count; - hctx->ccid3hctx_idle = 0; + DCCP_SKB_CB(skb)->dccpd_ccval = hc->tx_last_win_count; /* set the nominal send time for the next following packet */ - hctx->ccid3hctx_t_nom = ktime_add_us(hctx->ccid3hctx_t_nom, - hctx->ccid3hctx_t_ipi); - return 0; + 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, int more, - unsigned int len) +static void ccid3_hc_tx_packet_sent(struct sock *sk, unsigned int len) { - struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); - struct timeval now; - struct dccp_tx_hist_entry *packet; - - BUG_ON(hctx == NULL); + struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk); - ccid3_hc_tx_update_s(hctx, len); + ccid3_hc_tx_update_s(hc, len); - packet = dccp_tx_hist_entry_new(ccid3_tx_hist, GFP_ATOMIC); - if (unlikely(packet == NULL)) { + if (tfrc_tx_hist_add(&hc->tx_hist, dccp_sk(sk)->dccps_gss)) DCCP_CRIT("packet history - out of memory!"); - return; - } - dccp_tx_hist_add_entry(&hctx->ccid3hctx_hist, packet); - - dccp_timestamp(sk, &now); - packet->dccphtx_tstamp = now; - packet->dccphtx_seqno = dccp_sk(sk)->dccps_gss; - packet->dccphtx_rtt = hctx->ccid3hctx_rtt; - packet->dccphtx_sent = 1; } static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb) { - 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; + 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 pinv, r_sample; - - BUG_ON(hctx == NULL); + 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); - opt_recv = &hctx->ccid3hctx_options_received; - - switch (hctx->ccid3hctx_state) { - case TFRC_SSTATE_NO_FBACK: - case TFRC_SSTATE_FBACK: - /* get packet from history to look up t_recvdata */ - packet = dccp_tx_hist_find_entry(&hctx->ccid3hctx_hist, - DCCP_SKB_CB(skb)->dccpd_ack_seq); - if (unlikely(packet == NULL)) { - DCCP_WARN("%s(%p), seqno %llu(%s) doesn'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 receive rate in units of 64 * bytes/second */ - hctx->ccid3hctx_x_recv = opt_recv->ccid3or_receive_rate; - hctx->ccid3hctx_x_recv <<= 6; - - /* Update loss event rate */ - pinv = opt_recv->ccid3or_loss_event_rate; - if (pinv == ~0U || pinv == 0) /* see RFC 4342, 8.5 */ - hctx->ccid3hctx_p = 0; - else /* can not exceed 100% */ - hctx->ccid3hctx_p = 1000000 / pinv; - - dccp_timestamp(sk, &now); + /* 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); - /* - * Calculate new round trip sample as per [RFC 3448, 4.3] by - * R_sample = (now - t_recvdata) - t_elapsed - */ - r_sample = dccp_sample_rtt(sk, &now, &packet->dccphtx_tstamp); + /* + * 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); - /* - * 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) { + if (hc->tx_t_rto == 0) { /* - * Larger Initial Windows [RFC 4342, sec. 5] + * Initial feedback packet: Larger Initial Windows (4.2) */ - hctx->ccid3hctx_rtt = r_sample; - hctx->ccid3hctx_x = rfc3390_initial_rate(sk); - hctx->ccid3hctx_t_ld = now; + hc->tx_x = rfc3390_initial_rate(sk); + hc->tx_t_ld = now; - ccid3_update_send_interval(hctx); + ccid3_update_send_interval(hc); - ccid3_pr_debug("%s(%p), s=%u, MSS=%u, " - "R_sample=%uus, X=%u\n", dccp_role(sk), - sk, hctx->ccid3hctx_s, - dccp_sk(sk)->dccps_mss_cache, r_sample, - (unsigned)(hctx->ccid3hctx_x >> 6)); - - ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK); - } else { - hctx->ccid3hctx_rtt = (9 * hctx->ccid3hctx_rtt + - r_sample) / 10; - - /* Update sending rate (step 4 of [RFC 3448, 4.3]) */ - if (hctx->ccid3hctx_p > 0) - hctx->ccid3hctx_x_calc = - tfrc_calc_x(hctx->ccid3hctx_s, - hctx->ccid3hctx_rtt, - hctx->ccid3hctx_p); - ccid3_hc_tx_update_x(sk, &now); - - ccid3_pr_debug("%s(%p), RTT=%uus (sample=%uus), s=%u, " - "p=%u, X_calc=%u, X_recv=%u, X=%u\n", - dccp_role(sk), - sk, hctx->ccid3hctx_rtt, r_sample, - hctx->ccid3hctx_s, hctx->ccid3hctx_p, - hctx->ccid3hctx_x_calc, - (unsigned)(hctx->ccid3hctx_x_recv >> 6), - (unsigned)(hctx->ccid3hctx_x >> 6)); + goto done_computing_x; + } else if (hc->tx_p == 0) { + /* + * First feedback after nofeedback timer expiry (4.3) + */ + goto done_computing_x; } + } - /* unschedule no feedback timer */ - sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer); + /* 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); - /* 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); +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)); - /* - * Update timeout interval for the nofeedback timer. - * We use a configuration option to increase the lower bound. - * This can help avoid triggering the nofeedback timer too - * often ('spinning') on LANs with small RTTs. - */ - hctx->ccid3hctx_t_rto = max_t(u32, 4 * hctx->ccid3hctx_rtt, - CONFIG_IP_DCCP_CCID3_RTO * - (USEC_PER_SEC/1000)); - /* - * Schedule no feedback timer to expire in - * max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi) - */ - t_nfb = max(hctx->ccid3hctx_t_rto, 2 * hctx->ccid3hctx_t_ipi); + /* unschedule no feedback timer */ + sk_stop_timer(sk, &hc->tx_no_feedback_timer); - 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); + /* + * 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); - sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer, - jiffies + usecs_to_jiffies(t_nfb)); + /* + * 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); - /* set idle flag */ - hctx->ccid3hctx_idle = 1; - break; - case TFRC_SSTATE_NO_SENT: /* fall through */ - case TFRC_SSTATE_TERM: /* ignore feedback when closing */ - break; - } + 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, unsigned char option, - unsigned char len, u16 idx, - unsigned char *value) +static int ccid3_hc_tx_parse_options(struct sock *sk, u8 packet_type, + u8 option, u8 *optval, u8 optlen) { - 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; - } + 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: - if (unlikely(len != 4)) { - DCCP_WARN("%s(%p), invalid len %d " - "for TFRC_OPT_LOSS_EVENT_RATE\n", - dccp_role(sk), sk, len); - rc = -EINVAL; - } else { - opt_recv->ccid3or_loss_event_rate = - ntohl(*(__be32 *)value); - ccid3_pr_debug("%s(%p), LOSS_EVENT_RATE=%u\n", - dccp_role(sk), sk, - opt_recv->ccid3or_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; } - break; - case TFRC_OPT_LOSS_INTERVALS: - opt_recv->ccid3or_loss_intervals_idx = idx; - opt_recv->ccid3or_loss_intervals_len = len; - ccid3_pr_debug("%s(%p), LOSS_INTERVALS=(%u, %u)\n", - dccp_role(sk), sk, - opt_recv->ccid3or_loss_intervals_idx, - opt_recv->ccid3or_loss_intervals_len); - break; - case TFRC_OPT_RECEIVE_RATE: - if (unlikely(len != 4)) { - DCCP_WARN("%s(%p), invalid len %d " - "for TFRC_OPT_RECEIVE_RATE\n", - dccp_role(sk), sk, len); - rc = -EINVAL; - } else { - opt_recv->ccid3or_receive_rate = - ntohl(*(__be32 *)value); + 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_recv->ccid3or_receive_rate); + 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); } - break; } - - return rc; + return 0; } 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_rtt = 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); + struct ccid3_hc_tx_sock *hc = ccid_priv(ccid); + hc->tx_state = TFRC_SSTATE_NO_SENT; + hc->tx_hist = NULL; + setup_timer(&hc->tx_no_feedback_timer, + ccid3_hc_tx_no_feedback_timer, (unsigned long)sk); return 0; } static void ccid3_hc_tx_exit(struct sock *sk) { - struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); - - BUG_ON(hctx == NULL); + struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk); - 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); + 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) { - 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; + 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 *hctx = ccid3_hc_tx_sk(sk); + const struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk); + struct tfrc_tx_info tfrc; 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)) + if (len < sizeof(tfrc)) return -EINVAL; - len = sizeof(hctx->ccid3hctx_tfrc); - val = &hctx->ccid3hctx_tfrc; + 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; @@ -689,13 +559,21 @@ static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len, /* * Receiver Half-Connection Routines */ + +/* CCID3 feedback types */ +enum ccid3_fback_type { + CCID3_FBACK_NONE = 0, + CCID3_FBACK_INITIAL, + CCID3_FBACK_PERIODIC, + CCID3_FBACK_PARAM_CHANGE +}; + #ifdef CONFIG_IP_DCCP_CCID3_DEBUG static const char *ccid3_rx_state_name(enum ccid3_hc_rx_states state) { - static char *ccid3_rx_state_names[] = { + static const char *const ccid3_rx_state_names[] = { [TFRC_RSTATE_NO_DATA] = "NO_DATA", [TFRC_RSTATE_DATA] = "DATA", - [TFRC_RSTATE_TERM] = "TERM", }; return ccid3_rx_state_names[state]; @@ -705,76 +583,61 @@ static const char *ccid3_rx_state_name(enum ccid3_hc_rx_states state) 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; + 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); - hcrx->ccid3hcrx_state = state; + hc->rx_state = state; } -static inline void ccid3_hc_rx_update_s(struct ccid3_hc_rx_sock *hcrx, int len) +static void ccid3_hc_rx_send_feedback(struct sock *sk, + const struct sk_buff *skb, + enum ccid3_fback_type fbtype) { - 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 ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk); struct dccp_sock *dp = dccp_sk(sk); - struct dccp_rx_hist_entry *packet; - struct timeval now; - suseconds_t delta; - - ccid3_pr_debug("%s(%p) - entry \n", dccp_role(sk), sk); - - dccp_timestamp(sk, &now); + ktime_t now = ktime_get_real(); + s64 delta = 0; - switch (hcrx->ccid3hcrx_state) { - case TFRC_RSTATE_NO_DATA: - hcrx->ccid3hcrx_x_recv = 0; + switch (fbtype) { + case CCID3_FBACK_INITIAL: + hc->rx_x_recv = 0; + hc->rx_pinv = ~0U; /* see RFC 4342, 8.5 */ break; - case TFRC_RSTATE_DATA: - delta = timeval_delta(&now, - &hcrx->ccid3hcrx_tstamp_last_feedback); - DCCP_BUG_ON(delta < 0); - hcrx->ccid3hcrx_x_recv = - scaled_div32(hcrx->ccid3hcrx_bytes_recv, delta); + 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; + /* fall through */ + case CCID3_FBACK_PERIODIC: + delta = ktime_us_delta(now, hc->rx_tstamp_last_feedback); + if (delta <= 0) + DCCP_BUG("delta (%ld) <= 0", (long)delta); + else + hc->rx_x_recv = scaled_div32(hc->rx_bytes_recv, delta); break; - case TFRC_RSTATE_TERM: - DCCP_BUG("%s(%p) - Illegal state TERM", dccp_role(sk), sk); - return; - } - - packet = dccp_rx_hist_find_data_packet(&hcrx->ccid3hcrx_hist); - if (unlikely(packet == NULL)) { - DCCP_WARN("%s(%p), no data packet in history!\n", - dccp_role(sk), sk); + default: return; } - hcrx->ccid3hcrx_tstamp_last_feedback = now; - hcrx->ccid3hcrx_ccval_last_counter = packet->dccphrx_ccval; - hcrx->ccid3hcrx_bytes_recv = 0; - - /* Elapsed time information [RFC 4340, 13.2] in units of 10 * usecs */ - delta = timeval_delta(&now, &packet->dccphrx_tstamp); - DCCP_BUG_ON(delta < 0); - hcrx->ccid3hcrx_elapsed_time = delta / 10; + ccid3_pr_debug("Interval %ldusec, X_recv=%u, 1/p=%u\n", (long)delta, + hc->rx_x_recv, hc->rx_pinv); - if (hcrx->ccid3hcrx_p == 0) - hcrx->ccid3hcrx_pinv = ~0U; /* see RFC 4342, 8.5 */ - else if (hcrx->ccid3hcrx_p > 1000000) { - DCCP_WARN("p (%u) > 100%%\n", hcrx->ccid3hcrx_p); - hcrx->ccid3hcrx_pinv = 1; /* use 100% in this case */ - } else - hcrx->ccid3hcrx_pinv = 1000000 / hcrx->ccid3hcrx_p; + 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); @@ -782,261 +645,193 @@ static void ccid3_hc_rx_send_feedback(struct sock *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); + const struct ccid3_hc_rx_sock *hc = 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); + x_recv = htonl(hc->rx_x_recv); + pinv = htonl(hc->rx_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, + if (dccp_insert_option(skb, TFRC_OPT_LOSS_EVENT_RATE, &pinv, sizeof(pinv)) || - dccp_insert_option(sk, skb, TFRC_OPT_RECEIVE_RATE, + dccp_insert_option(skb, TFRC_OPT_RECEIVE_RATE, &x_recv, sizeof(x_recv))) return -1; return 0; } -static int ccid3_hc_rx_detect_loss(struct sock *sk, - struct dccp_rx_hist_entry *packet) +/** + * ccid3_first_li - Implements [RFC 5348, 6.3.1] + * + * Determine the length of the first loss interval via inverse lookup. + * Assume that X_recv can be computed by the throughput equation + * s + * X_recv = -------- + * R * fval + * Find some p such that f(p) = fval; return 1/p (scaled). + */ +static u32 ccid3_first_li(struct sock *sk) { - struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); - 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; - } + struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk); + u32 x_recv, p, delta; + u64 fval; + if (hc->rx_rtt == 0) { + DCCP_WARN("No RTT estimate available, using fallback RTT\n"); + hc->rx_rtt = DCCP_FALLBACK_RTT; + } - while (dccp_delta_seqno(hcrx->ccid3hcrx_seqno_nonloss, seqno) - > TFRC_RECV_NUM_LATE_LOSS) { - loss = 1; - dccp_li_update_li(sk, - &hcrx->ccid3hcrx_li_hist, - &hcrx->ccid3hcrx_hist, - &hcrx->ccid3hcrx_tstamp_last_feedback, - hcrx->ccid3hcrx_s, - hcrx->ccid3hcrx_bytes_recv, - hcrx->ccid3hcrx_x_recv, - 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); + delta = ktime_to_us(net_timedelta(hc->rx_tstamp_last_feedback)); + 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; } - /* 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; - } + 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); -detect_out: - dccp_rx_hist_add_packet(ccid3_rx_hist, &hcrx->ccid3hcrx_hist, - &hcrx->ccid3hcrx_li_hist, packet, - hcrx->ccid3hcrx_seqno_nonloss); - return loss; + return p == 0 ? ~0U : scaled_div(1, p); } static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb) { - struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); - const struct dccp_options_received *opt_recv; - struct dccp_rx_hist_entry *packet; - struct timeval now; - u32 p_prev, r_sample, rtt_prev; - 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); - r_sample = dccp_sample_rtt(sk, &now, NULL); + 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 (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 (tfrc_rx_hist_duplicate(&hc->rx_hist, skb)) + return; /* done receiving */ - if (rtt_prev != hcrx->ccid3hcrx_rtt) - ccid3_pr_debug("%s(%p), New RTT=%uus, elapsed time=%u\n", - dccp_role(sk), 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; + 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; } - packet = dccp_rx_hist_entry_new(ccid3_rx_hist, sk, opt_recv->dccpor_ndp, - skb, GFP_ATOMIC); - if (unlikely(packet == NULL)) { - DCCP_WARN("%s(%p), Not enough mem to add rx packet " - "to history, consider it lost!\n", dccp_role(sk), sk); - return; + /* + * 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; } - loss = ccid3_hc_rx_detect_loss(sk, packet); + if (tfrc_rx_hist_loss_pending(&hc->rx_hist)) + return; /* done receiving */ - 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); + /* + * Handle data packets: RTT sampling and monitoring p + */ + if (unlikely(!is_data_packet)) + goto update_records; - switch (hcrx->ccid3hcrx_state) { - case TFRC_RSTATE_NO_DATA: - ccid3_pr_debug("%s(%p, state=%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; + 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); - dccp_timestamp(sk, &now); - if ((timeval_delta(&now, &hcrx->ccid3hcrx_tstamp_last_ack) - - (suseconds_t)hcrx->ccid3hcrx_rtt) >= 0) { - hcrx->ccid3hcrx_tstamp_last_ack = now; - ccid3_hc_rx_send_feedback(sk); - } - return; - case TFRC_RSTATE_TERM: - DCCP_BUG("%s(%p) - Illegal state TERM", dccp_role(sk), sk); - return; + } 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; } - /* Dealing with packet loss */ - ccid3_pr_debug("%s(%p, state=%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); + /* + * 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; - /* Scaling up by 1000000 as fixed decimal */ - if (i_mean != 0) - hcrx->ccid3hcrx_p = 1000000 / i_mean; - } else - DCCP_BUG("empty loss history"); +update_records: + tfrc_rx_hist_add_packet(&hc->rx_hist, skb, ndp); - if (hcrx->ccid3hcrx_p > p_prev) { - ccid3_hc_rx_send_feedback(sk); - return; - } +done_receiving: + if (do_feedback) + ccid3_hc_rx_send_feedback(sk, skb, do_feedback); } static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk) { - struct ccid3_hc_rx_sock *hcrx = ccid_priv(ccid); + struct ccid3_hc_rx_sock *hc = ccid_priv(ccid); - ccid3_pr_debug("entry\n"); - - 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 = 0; - return 0; + 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 *hcrx = ccid3_hc_rx_sk(sk); - - BUG_ON(hcrx == NULL); - - ccid3_hc_rx_set_state(sk, TFRC_RSTATE_TERM); + struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk); - /* Empty packet history */ - dccp_rx_hist_purge(ccid3_rx_hist, &hcrx->ccid3hcrx_hist); - - /* Empty loss interval history */ - dccp_li_hist_purge(&hcrx->ccid3hcrx_li_hist); + 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) { - 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_ca_state = ccid3_hc_rx_sk(sk)->rx_state; info->tcpi_options |= TCPI_OPT_TIMESTAMPS; - info->tcpi_rcv_rtt = hcrx->ccid3hcrx_rtt; + 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 *hcrx = ccid3_hc_rx_sk(sk); + const struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk); + struct tfrc_rx_info rx_info; const void *val; - /* Listen socks doesn't have a private CCID block */ - if (sk->sk_state == DCCP_LISTEN) - return -EINVAL; - switch (optname) { case DCCP_SOCKOPT_CCID_RX_INFO: - if (len < sizeof(hcrx->ccid3hcrx_tfrc)) + if (len < sizeof(rx_info)) return -EINVAL; - len = sizeof(hcrx->ccid3hcrx_tfrc); - val = &hcrx->ccid3hcrx_tfrc; + 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; @@ -1048,10 +843,9 @@ static int ccid3_hc_rx_getsockopt(struct sock *sk, const int optname, int len, return 0; } -static struct ccid_operations ccid3 = { +struct ccid_operations ccid3_ops = { .ccid_id = DCCPC_CCID3, - .ccid_name = "ccid3", - .ccid_owner = THIS_MODULE, + .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, @@ -1071,55 +865,6 @@ static struct ccid_operations ccid3 = { }; #ifdef CONFIG_IP_DCCP_CCID3_DEBUG -module_param(ccid3_debug, int, 0444); -MODULE_PARM_DESC(ccid3_debug, "Enable debug messages"); +module_param(ccid3_debug, bool, 0644); +MODULE_PARM_DESC(ccid3_debug, "Enable CCID-3 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; - - rc = ccid_register(&ccid3); - if (rc != 0) - goto out_free_tx; -out: - return rc; - -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; - } -} -module_exit(ccid3_module_exit); - -MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>, " - "Arnaldo Carvalho de Melo <acme@ghostprotocols.net>"); -MODULE_DESCRIPTION("DCCP TFRC CCID3 CCID"); -MODULE_LICENSE("GPL"); -MODULE_ALIAS("net-dccp-ccid-3"); |