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- /*
- * Copyright (c) 2005, 2006 Andrea Bittau <a.bittau@cs.ucl.ac.uk>
- *
- * Changes to meet Linux coding standards, and DCCP infrastructure fixes.
- *
- * Copyright (c) 2006 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
- *
- * 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.
- */
- /*
- * This implementation should follow RFC 4341
- */
- #include <linux/slab.h>
- #include "../feat.h"
- #include "ccid2.h"
- #ifdef CONFIG_IP_DCCP_CCID2_DEBUG
- static bool ccid2_debug;
- #define ccid2_pr_debug(format, a...) DCCP_PR_DEBUG(ccid2_debug, format, ##a)
- #else
- #define ccid2_pr_debug(format, a...)
- #endif
- static int ccid2_hc_tx_alloc_seq(struct ccid2_hc_tx_sock *hc)
- {
- struct ccid2_seq *seqp;
- int i;
- /* check if we have space to preserve the pointer to the buffer */
- if (hc->tx_seqbufc >= (sizeof(hc->tx_seqbuf) /
- sizeof(struct ccid2_seq *)))
- return -ENOMEM;
- /* allocate buffer and initialize linked list */
- seqp = kmalloc(CCID2_SEQBUF_LEN * sizeof(struct ccid2_seq), gfp_any());
- if (seqp == NULL)
- return -ENOMEM;
- for (i = 0; i < (CCID2_SEQBUF_LEN - 1); i++) {
- seqp[i].ccid2s_next = &seqp[i + 1];
- seqp[i + 1].ccid2s_prev = &seqp[i];
- }
- seqp[CCID2_SEQBUF_LEN - 1].ccid2s_next = seqp;
- seqp->ccid2s_prev = &seqp[CCID2_SEQBUF_LEN - 1];
- /* This is the first allocation. Initiate the head and tail. */
- if (hc->tx_seqbufc == 0)
- hc->tx_seqh = hc->tx_seqt = seqp;
- else {
- /* link the existing list with the one we just created */
- hc->tx_seqh->ccid2s_next = seqp;
- seqp->ccid2s_prev = hc->tx_seqh;
- hc->tx_seqt->ccid2s_prev = &seqp[CCID2_SEQBUF_LEN - 1];
- seqp[CCID2_SEQBUF_LEN - 1].ccid2s_next = hc->tx_seqt;
- }
- /* store the original pointer to the buffer so we can free it */
- hc->tx_seqbuf[hc->tx_seqbufc] = seqp;
- hc->tx_seqbufc++;
- return 0;
- }
- static int ccid2_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
- {
- if (ccid2_cwnd_network_limited(ccid2_hc_tx_sk(sk)))
- return CCID_PACKET_WILL_DEQUEUE_LATER;
- return CCID_PACKET_SEND_AT_ONCE;
- }
- static void ccid2_change_l_ack_ratio(struct sock *sk, u32 val)
- {
- u32 max_ratio = DIV_ROUND_UP(ccid2_hc_tx_sk(sk)->tx_cwnd, 2);
- /*
- * Ensure that Ack Ratio does not exceed ceil(cwnd/2), which is (2) from
- * RFC 4341, 6.1.2. We ignore the statement that Ack Ratio 2 is always
- * acceptable since this causes starvation/deadlock whenever cwnd < 2.
- * The same problem arises when Ack Ratio is 0 (ie. Ack Ratio disabled).
- */
- if (val == 0 || val > max_ratio) {
- DCCP_WARN("Limiting Ack Ratio (%u) to %u\n", val, max_ratio);
- val = max_ratio;
- }
- dccp_feat_signal_nn_change(sk, DCCPF_ACK_RATIO,
- min_t(u32, val, DCCPF_ACK_RATIO_MAX));
- }
- static void ccid2_check_l_ack_ratio(struct sock *sk)
- {
- struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
- /*
- * After a loss, idle period, application limited period, or RTO we
- * need to check that the ack ratio is still less than the congestion
- * window. Otherwise, we will send an entire congestion window of
- * packets and got no response because we haven't sent ack ratio
- * packets yet.
- * If the ack ratio does need to be reduced, we reduce it to half of
- * the congestion window (or 1 if that's zero) instead of to the
- * congestion window. This prevents problems if one ack is lost.
- */
- if (dccp_feat_nn_get(sk, DCCPF_ACK_RATIO) > hc->tx_cwnd)
- ccid2_change_l_ack_ratio(sk, hc->tx_cwnd/2 ? : 1U);
- }
- static void ccid2_change_l_seq_window(struct sock *sk, u64 val)
- {
- dccp_feat_signal_nn_change(sk, DCCPF_SEQUENCE_WINDOW,
- clamp_val(val, DCCPF_SEQ_WMIN,
- DCCPF_SEQ_WMAX));
- }
- static void ccid2_hc_tx_rto_expire(unsigned long data)
- {
- struct sock *sk = (struct sock *)data;
- struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
- const bool sender_was_blocked = ccid2_cwnd_network_limited(hc);
- bh_lock_sock(sk);
- if (sock_owned_by_user(sk)) {
- sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + HZ / 5);
- goto out;
- }
- ccid2_pr_debug("RTO_EXPIRE\n");
- /* back-off timer */
- hc->tx_rto <<= 1;
- if (hc->tx_rto > DCCP_RTO_MAX)
- hc->tx_rto = DCCP_RTO_MAX;
- /* adjust pipe, cwnd etc */
- hc->tx_ssthresh = hc->tx_cwnd / 2;
- if (hc->tx_ssthresh < 2)
- hc->tx_ssthresh = 2;
- hc->tx_cwnd = 1;
- hc->tx_pipe = 0;
- /* clear state about stuff we sent */
- hc->tx_seqt = hc->tx_seqh;
- hc->tx_packets_acked = 0;
- /* clear ack ratio state. */
- hc->tx_rpseq = 0;
- hc->tx_rpdupack = -1;
- ccid2_change_l_ack_ratio(sk, 1);
- /* if we were blocked before, we may now send cwnd=1 packet */
- if (sender_was_blocked)
- tasklet_schedule(&dccp_sk(sk)->dccps_xmitlet);
- /* restart backed-off timer */
- sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + hc->tx_rto);
- out:
- bh_unlock_sock(sk);
- sock_put(sk);
- }
- /*
- * Congestion window validation (RFC 2861).
- */
- static bool ccid2_do_cwv = true;
- module_param(ccid2_do_cwv, bool, 0644);
- MODULE_PARM_DESC(ccid2_do_cwv, "Perform RFC2861 Congestion Window Validation");
- /**
- * ccid2_update_used_window - Track how much of cwnd is actually used
- * This is done in addition to CWV. The sender needs to have an idea of how many
- * packets may be in flight, to set the local Sequence Window value accordingly
- * (RFC 4340, 7.5.2). The CWV mechanism is exploited to keep track of the
- * maximum-used window. We use an EWMA low-pass filter to filter out noise.
- */
- static void ccid2_update_used_window(struct ccid2_hc_tx_sock *hc, u32 new_wnd)
- {
- hc->tx_expected_wnd = (3 * hc->tx_expected_wnd + new_wnd) / 4;
- }
- /* This borrows the code of tcp_cwnd_application_limited() */
- static void ccid2_cwnd_application_limited(struct sock *sk, const u32 now)
- {
- struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
- /* don't reduce cwnd below the initial window (IW) */
- u32 init_win = rfc3390_bytes_to_packets(dccp_sk(sk)->dccps_mss_cache),
- win_used = max(hc->tx_cwnd_used, init_win);
- if (win_used < hc->tx_cwnd) {
- hc->tx_ssthresh = max(hc->tx_ssthresh,
- (hc->tx_cwnd >> 1) + (hc->tx_cwnd >> 2));
- hc->tx_cwnd = (hc->tx_cwnd + win_used) >> 1;
- }
- hc->tx_cwnd_used = 0;
- hc->tx_cwnd_stamp = now;
- ccid2_check_l_ack_ratio(sk);
- }
- /* This borrows the code of tcp_cwnd_restart() */
- static void ccid2_cwnd_restart(struct sock *sk, const u32 now)
- {
- struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
- u32 cwnd = hc->tx_cwnd, restart_cwnd,
- iwnd = rfc3390_bytes_to_packets(dccp_sk(sk)->dccps_mss_cache);
- hc->tx_ssthresh = max(hc->tx_ssthresh, (cwnd >> 1) + (cwnd >> 2));
- /* don't reduce cwnd below the initial window (IW) */
- restart_cwnd = min(cwnd, iwnd);
- cwnd >>= (now - hc->tx_lsndtime) / hc->tx_rto;
- hc->tx_cwnd = max(cwnd, restart_cwnd);
- hc->tx_cwnd_stamp = now;
- hc->tx_cwnd_used = 0;
- ccid2_check_l_ack_ratio(sk);
- }
- static void ccid2_hc_tx_packet_sent(struct sock *sk, unsigned int len)
- {
- struct dccp_sock *dp = dccp_sk(sk);
- struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
- const u32 now = ccid2_time_stamp;
- struct ccid2_seq *next;
- /* slow-start after idle periods (RFC 2581, RFC 2861) */
- if (ccid2_do_cwv && !hc->tx_pipe &&
- (s32)(now - hc->tx_lsndtime) >= hc->tx_rto)
- ccid2_cwnd_restart(sk, now);
- hc->tx_lsndtime = now;
- hc->tx_pipe += 1;
- /* see whether cwnd was fully used (RFC 2861), update expected window */
- if (ccid2_cwnd_network_limited(hc)) {
- ccid2_update_used_window(hc, hc->tx_cwnd);
- hc->tx_cwnd_used = 0;
- hc->tx_cwnd_stamp = now;
- } else {
- if (hc->tx_pipe > hc->tx_cwnd_used)
- hc->tx_cwnd_used = hc->tx_pipe;
- ccid2_update_used_window(hc, hc->tx_cwnd_used);
- if (ccid2_do_cwv && (s32)(now - hc->tx_cwnd_stamp) >= hc->tx_rto)
- ccid2_cwnd_application_limited(sk, now);
- }
- hc->tx_seqh->ccid2s_seq = dp->dccps_gss;
- hc->tx_seqh->ccid2s_acked = 0;
- hc->tx_seqh->ccid2s_sent = now;
- next = hc->tx_seqh->ccid2s_next;
- /* check if we need to alloc more space */
- if (next == hc->tx_seqt) {
- if (ccid2_hc_tx_alloc_seq(hc)) {
- DCCP_CRIT("packet history - out of memory!");
- /* FIXME: find a more graceful way to bail out */
- return;
- }
- next = hc->tx_seqh->ccid2s_next;
- BUG_ON(next == hc->tx_seqt);
- }
- hc->tx_seqh = next;
- ccid2_pr_debug("cwnd=%d pipe=%d\n", hc->tx_cwnd, hc->tx_pipe);
- /*
- * FIXME: The code below is broken and the variables have been removed
- * from the socket struct. The `ackloss' variable was always set to 0,
- * and with arsent there are several problems:
- * (i) it doesn't just count the number of Acks, but all sent packets;
- * (ii) it is expressed in # of packets, not # of windows, so the
- * comparison below uses the wrong formula: Appendix A of RFC 4341
- * comes up with the number K = cwnd / (R^2 - R) of consecutive windows
- * of data with no lost or marked Ack packets. If arsent were the # of
- * consecutive Acks received without loss, then Ack Ratio needs to be
- * decreased by 1 when
- * arsent >= K * cwnd / R = cwnd^2 / (R^3 - R^2)
- * where cwnd / R is the number of Acks received per window of data
- * (cf. RFC 4341, App. A). The problems are that
- * - arsent counts other packets as well;
- * - the comparison uses a formula different from RFC 4341;
- * - computing a cubic/quadratic equation each time is too complicated.
- * Hence a different algorithm is needed.
- */
- #if 0
- /* Ack Ratio. Need to maintain a concept of how many windows we sent */
- hc->tx_arsent++;
- /* We had an ack loss in this window... */
- if (hc->tx_ackloss) {
- if (hc->tx_arsent >= hc->tx_cwnd) {
- hc->tx_arsent = 0;
- hc->tx_ackloss = 0;
- }
- } else {
- /* No acks lost up to now... */
- /* decrease ack ratio if enough packets were sent */
- if (dp->dccps_l_ack_ratio > 1) {
- /* XXX don't calculate denominator each time */
- int denom = dp->dccps_l_ack_ratio * dp->dccps_l_ack_ratio -
- dp->dccps_l_ack_ratio;
- denom = hc->tx_cwnd * hc->tx_cwnd / denom;
- if (hc->tx_arsent >= denom) {
- ccid2_change_l_ack_ratio(sk, dp->dccps_l_ack_ratio - 1);
- hc->tx_arsent = 0;
- }
- } else {
- /* we can't increase ack ratio further [1] */
- hc->tx_arsent = 0; /* or maybe set it to cwnd*/
- }
- }
- #endif
- sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + hc->tx_rto);
- #ifdef CONFIG_IP_DCCP_CCID2_DEBUG
- do {
- struct ccid2_seq *seqp = hc->tx_seqt;
- while (seqp != hc->tx_seqh) {
- ccid2_pr_debug("out seq=%llu acked=%d time=%u\n",
- (unsigned long long)seqp->ccid2s_seq,
- seqp->ccid2s_acked, seqp->ccid2s_sent);
- seqp = seqp->ccid2s_next;
- }
- } while (0);
- ccid2_pr_debug("=========\n");
- #endif
- }
- /**
- * ccid2_rtt_estimator - Sample RTT and compute RTO using RFC2988 algorithm
- * This code is almost identical with TCP's tcp_rtt_estimator(), since
- * - it has a higher sampling frequency (recommended by RFC 1323),
- * - the RTO does not collapse into RTT due to RTTVAR going towards zero,
- * - it is simple (cf. more complex proposals such as Eifel timer or research
- * which suggests that the gain should be set according to window size),
- * - in tests it was found to work well with CCID2 [gerrit].
- */
- static void ccid2_rtt_estimator(struct sock *sk, const long mrtt)
- {
- struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
- long m = mrtt ? : 1;
- if (hc->tx_srtt == 0) {
- /* First measurement m */
- hc->tx_srtt = m << 3;
- hc->tx_mdev = m << 1;
- hc->tx_mdev_max = max(hc->tx_mdev, tcp_rto_min(sk));
- hc->tx_rttvar = hc->tx_mdev_max;
- hc->tx_rtt_seq = dccp_sk(sk)->dccps_gss;
- } else {
- /* Update scaled SRTT as SRTT += 1/8 * (m - SRTT) */
- m -= (hc->tx_srtt >> 3);
- hc->tx_srtt += m;
- /* Similarly, update scaled mdev with regard to |m| */
- if (m < 0) {
- m = -m;
- m -= (hc->tx_mdev >> 2);
- /*
- * This neutralises RTO increase when RTT < SRTT - mdev
- * (see P. Sarolahti, A. Kuznetsov,"Congestion Control
- * in Linux TCP", USENIX 2002, pp. 49-62).
- */
- if (m > 0)
- m >>= 3;
- } else {
- m -= (hc->tx_mdev >> 2);
- }
- hc->tx_mdev += m;
- if (hc->tx_mdev > hc->tx_mdev_max) {
- hc->tx_mdev_max = hc->tx_mdev;
- if (hc->tx_mdev_max > hc->tx_rttvar)
- hc->tx_rttvar = hc->tx_mdev_max;
- }
- /*
- * Decay RTTVAR at most once per flight, exploiting that
- * 1) pipe <= cwnd <= Sequence_Window = W (RFC 4340, 7.5.2)
- * 2) AWL = GSS-W+1 <= GAR <= GSS (RFC 4340, 7.5.1)
- * GAR is a useful bound for FlightSize = pipe.
- * AWL is probably too low here, as it over-estimates pipe.
- */
- if (after48(dccp_sk(sk)->dccps_gar, hc->tx_rtt_seq)) {
- if (hc->tx_mdev_max < hc->tx_rttvar)
- hc->tx_rttvar -= (hc->tx_rttvar -
- hc->tx_mdev_max) >> 2;
- hc->tx_rtt_seq = dccp_sk(sk)->dccps_gss;
- hc->tx_mdev_max = tcp_rto_min(sk);
- }
- }
- /*
- * Set RTO from SRTT and RTTVAR
- * As in TCP, 4 * RTTVAR >= TCP_RTO_MIN, giving a minimum RTO of 200 ms.
- * This agrees with RFC 4341, 5:
- * "Because DCCP does not retransmit data, DCCP does not require
- * TCP's recommended minimum timeout of one second".
- */
- hc->tx_rto = (hc->tx_srtt >> 3) + hc->tx_rttvar;
- if (hc->tx_rto > DCCP_RTO_MAX)
- hc->tx_rto = DCCP_RTO_MAX;
- }
- static void ccid2_new_ack(struct sock *sk, struct ccid2_seq *seqp,
- unsigned int *maxincr)
- {
- struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
- struct dccp_sock *dp = dccp_sk(sk);
- int r_seq_used = hc->tx_cwnd / dp->dccps_l_ack_ratio;
- if (hc->tx_cwnd < dp->dccps_l_seq_win &&
- r_seq_used < dp->dccps_r_seq_win) {
- if (hc->tx_cwnd < hc->tx_ssthresh) {
- if (*maxincr > 0 && ++hc->tx_packets_acked >= 2) {
- hc->tx_cwnd += 1;
- *maxincr -= 1;
- hc->tx_packets_acked = 0;
- }
- } else if (++hc->tx_packets_acked >= hc->tx_cwnd) {
- hc->tx_cwnd += 1;
- hc->tx_packets_acked = 0;
- }
- }
- /*
- * Adjust the local sequence window and the ack ratio to allow about
- * 5 times the number of packets in the network (RFC 4340 7.5.2)
- */
- if (r_seq_used * CCID2_WIN_CHANGE_FACTOR >= dp->dccps_r_seq_win)
- ccid2_change_l_ack_ratio(sk, dp->dccps_l_ack_ratio * 2);
- else if (r_seq_used * CCID2_WIN_CHANGE_FACTOR < dp->dccps_r_seq_win/2)
- ccid2_change_l_ack_ratio(sk, dp->dccps_l_ack_ratio / 2 ? : 1U);
- if (hc->tx_cwnd * CCID2_WIN_CHANGE_FACTOR >= dp->dccps_l_seq_win)
- ccid2_change_l_seq_window(sk, dp->dccps_l_seq_win * 2);
- else if (hc->tx_cwnd * CCID2_WIN_CHANGE_FACTOR < dp->dccps_l_seq_win/2)
- ccid2_change_l_seq_window(sk, dp->dccps_l_seq_win / 2);
- /*
- * FIXME: RTT is sampled several times per acknowledgment (for each
- * entry in the Ack Vector), instead of once per Ack (as in TCP SACK).
- * This causes the RTT to be over-estimated, since the older entries
- * in the Ack Vector have earlier sending times.
- * The cleanest solution is to not use the ccid2s_sent field at all
- * and instead use DCCP timestamps: requires changes in other places.
- */
- ccid2_rtt_estimator(sk, ccid2_time_stamp - seqp->ccid2s_sent);
- }
- static void ccid2_congestion_event(struct sock *sk, struct ccid2_seq *seqp)
- {
- struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
- if ((s32)(seqp->ccid2s_sent - hc->tx_last_cong) < 0) {
- ccid2_pr_debug("Multiple losses in an RTT---treating as one\n");
- return;
- }
- hc->tx_last_cong = ccid2_time_stamp;
- hc->tx_cwnd = hc->tx_cwnd / 2 ? : 1U;
- hc->tx_ssthresh = max(hc->tx_cwnd, 2U);
- ccid2_check_l_ack_ratio(sk);
- }
- static int ccid2_hc_tx_parse_options(struct sock *sk, u8 packet_type,
- u8 option, u8 *optval, u8 optlen)
- {
- struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
- switch (option) {
- case DCCPO_ACK_VECTOR_0:
- case DCCPO_ACK_VECTOR_1:
- return dccp_ackvec_parsed_add(&hc->tx_av_chunks, optval, optlen,
- option - DCCPO_ACK_VECTOR_0);
- }
- return 0;
- }
- static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
- {
- struct dccp_sock *dp = dccp_sk(sk);
- struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
- const bool sender_was_blocked = ccid2_cwnd_network_limited(hc);
- struct dccp_ackvec_parsed *avp;
- u64 ackno, seqno;
- struct ccid2_seq *seqp;
- int done = 0;
- unsigned int maxincr = 0;
- /* check reverse path congestion */
- seqno = DCCP_SKB_CB(skb)->dccpd_seq;
- /* XXX this whole "algorithm" is broken. Need to fix it to keep track
- * of the seqnos of the dupacks so that rpseq and rpdupack are correct
- * -sorbo.
- */
- /* need to bootstrap */
- if (hc->tx_rpdupack == -1) {
- hc->tx_rpdupack = 0;
- hc->tx_rpseq = seqno;
- } else {
- /* check if packet is consecutive */
- if (dccp_delta_seqno(hc->tx_rpseq, seqno) == 1)
- hc->tx_rpseq = seqno;
- /* it's a later packet */
- else if (after48(seqno, hc->tx_rpseq)) {
- hc->tx_rpdupack++;
- /* check if we got enough dupacks */
- if (hc->tx_rpdupack >= NUMDUPACK) {
- hc->tx_rpdupack = -1; /* XXX lame */
- hc->tx_rpseq = 0;
- #ifdef __CCID2_COPES_GRACEFULLY_WITH_ACK_CONGESTION_CONTROL__
- /*
- * FIXME: Ack Congestion Control is broken; in
- * the current state instabilities occurred with
- * Ack Ratios greater than 1; causing hang-ups
- * and long RTO timeouts. This needs to be fixed
- * before opening up dynamic changes. -- gerrit
- */
- ccid2_change_l_ack_ratio(sk, 2 * dp->dccps_l_ack_ratio);
- #endif
- }
- }
- }
- /* check forward path congestion */
- if (dccp_packet_without_ack(skb))
- return;
- /* still didn't send out new data packets */
- if (hc->tx_seqh == hc->tx_seqt)
- goto done;
- ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq;
- if (after48(ackno, hc->tx_high_ack))
- hc->tx_high_ack = ackno;
- seqp = hc->tx_seqt;
- while (before48(seqp->ccid2s_seq, ackno)) {
- seqp = seqp->ccid2s_next;
- if (seqp == hc->tx_seqh) {
- seqp = hc->tx_seqh->ccid2s_prev;
- break;
- }
- }
- /*
- * In slow-start, cwnd can increase up to a maximum of Ack Ratio/2
- * packets per acknowledgement. Rounding up avoids that cwnd is not
- * advanced when Ack Ratio is 1 and gives a slight edge otherwise.
- */
- if (hc->tx_cwnd < hc->tx_ssthresh)
- maxincr = DIV_ROUND_UP(dp->dccps_l_ack_ratio, 2);
- /* go through all ack vectors */
- list_for_each_entry(avp, &hc->tx_av_chunks, node) {
- /* go through this ack vector */
- for (; avp->len--; avp->vec++) {
- u64 ackno_end_rl = SUB48(ackno,
- dccp_ackvec_runlen(avp->vec));
- ccid2_pr_debug("ackvec %llu |%u,%u|\n",
- (unsigned long long)ackno,
- dccp_ackvec_state(avp->vec) >> 6,
- dccp_ackvec_runlen(avp->vec));
- /* if the seqno we are analyzing is larger than the
- * current ackno, then move towards the tail of our
- * seqnos.
- */
- while (after48(seqp->ccid2s_seq, ackno)) {
- if (seqp == hc->tx_seqt) {
- done = 1;
- break;
- }
- seqp = seqp->ccid2s_prev;
- }
- if (done)
- break;
- /* check all seqnos in the range of the vector
- * run length
- */
- while (between48(seqp->ccid2s_seq,ackno_end_rl,ackno)) {
- const u8 state = dccp_ackvec_state(avp->vec);
- /* new packet received or marked */
- if (state != DCCPAV_NOT_RECEIVED &&
- !seqp->ccid2s_acked) {
- if (state == DCCPAV_ECN_MARKED)
- ccid2_congestion_event(sk,
- seqp);
- else
- ccid2_new_ack(sk, seqp,
- &maxincr);
- seqp->ccid2s_acked = 1;
- ccid2_pr_debug("Got ack for %llu\n",
- (unsigned long long)seqp->ccid2s_seq);
- hc->tx_pipe--;
- }
- if (seqp == hc->tx_seqt) {
- done = 1;
- break;
- }
- seqp = seqp->ccid2s_prev;
- }
- if (done)
- break;
- ackno = SUB48(ackno_end_rl, 1);
- }
- if (done)
- break;
- }
- /* The state about what is acked should be correct now
- * Check for NUMDUPACK
- */
- seqp = hc->tx_seqt;
- while (before48(seqp->ccid2s_seq, hc->tx_high_ack)) {
- seqp = seqp->ccid2s_next;
- if (seqp == hc->tx_seqh) {
- seqp = hc->tx_seqh->ccid2s_prev;
- break;
- }
- }
- done = 0;
- while (1) {
- if (seqp->ccid2s_acked) {
- done++;
- if (done == NUMDUPACK)
- break;
- }
- if (seqp == hc->tx_seqt)
- break;
- seqp = seqp->ccid2s_prev;
- }
- /* If there are at least 3 acknowledgements, anything unacknowledged
- * below the last sequence number is considered lost
- */
- if (done == NUMDUPACK) {
- struct ccid2_seq *last_acked = seqp;
- /* check for lost packets */
- while (1) {
- if (!seqp->ccid2s_acked) {
- ccid2_pr_debug("Packet lost: %llu\n",
- (unsigned long long)seqp->ccid2s_seq);
- /* XXX need to traverse from tail -> head in
- * order to detect multiple congestion events in
- * one ack vector.
- */
- ccid2_congestion_event(sk, seqp);
- hc->tx_pipe--;
- }
- if (seqp == hc->tx_seqt)
- break;
- seqp = seqp->ccid2s_prev;
- }
- hc->tx_seqt = last_acked;
- }
- /* trim acked packets in tail */
- while (hc->tx_seqt != hc->tx_seqh) {
- if (!hc->tx_seqt->ccid2s_acked)
- break;
- hc->tx_seqt = hc->tx_seqt->ccid2s_next;
- }
- /* restart RTO timer if not all outstanding data has been acked */
- if (hc->tx_pipe == 0)
- sk_stop_timer(sk, &hc->tx_rtotimer);
- else
- sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + hc->tx_rto);
- done:
- /* check if incoming Acks allow pending packets to be sent */
- if (sender_was_blocked && !ccid2_cwnd_network_limited(hc))
- tasklet_schedule(&dccp_sk(sk)->dccps_xmitlet);
- dccp_ackvec_parsed_cleanup(&hc->tx_av_chunks);
- }
- static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk)
- {
- struct ccid2_hc_tx_sock *hc = ccid_priv(ccid);
- struct dccp_sock *dp = dccp_sk(sk);
- u32 max_ratio;
- /* RFC 4341, 5: initialise ssthresh to arbitrarily high (max) value */
- hc->tx_ssthresh = ~0U;
- /* Use larger initial windows (RFC 4341, section 5). */
- hc->tx_cwnd = rfc3390_bytes_to_packets(dp->dccps_mss_cache);
- hc->tx_expected_wnd = hc->tx_cwnd;
- /* Make sure that Ack Ratio is enabled and within bounds. */
- max_ratio = DIV_ROUND_UP(hc->tx_cwnd, 2);
- if (dp->dccps_l_ack_ratio == 0 || dp->dccps_l_ack_ratio > max_ratio)
- dp->dccps_l_ack_ratio = max_ratio;
- /* XXX init ~ to window size... */
- if (ccid2_hc_tx_alloc_seq(hc))
- return -ENOMEM;
- hc->tx_rto = DCCP_TIMEOUT_INIT;
- hc->tx_rpdupack = -1;
- hc->tx_last_cong = hc->tx_lsndtime = hc->tx_cwnd_stamp = ccid2_time_stamp;
- hc->tx_cwnd_used = 0;
- setup_timer(&hc->tx_rtotimer, ccid2_hc_tx_rto_expire,
- (unsigned long)sk);
- INIT_LIST_HEAD(&hc->tx_av_chunks);
- return 0;
- }
- static void ccid2_hc_tx_exit(struct sock *sk)
- {
- struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
- int i;
- sk_stop_timer(sk, &hc->tx_rtotimer);
- for (i = 0; i < hc->tx_seqbufc; i++)
- kfree(hc->tx_seqbuf[i]);
- hc->tx_seqbufc = 0;
- }
- static void ccid2_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
- {
- struct ccid2_hc_rx_sock *hc = ccid2_hc_rx_sk(sk);
- if (!dccp_data_packet(skb))
- return;
- if (++hc->rx_num_data_pkts >= dccp_sk(sk)->dccps_r_ack_ratio) {
- dccp_send_ack(sk);
- hc->rx_num_data_pkts = 0;
- }
- }
- struct ccid_operations ccid2_ops = {
- .ccid_id = DCCPC_CCID2,
- .ccid_name = "TCP-like",
- .ccid_hc_tx_obj_size = sizeof(struct ccid2_hc_tx_sock),
- .ccid_hc_tx_init = ccid2_hc_tx_init,
- .ccid_hc_tx_exit = ccid2_hc_tx_exit,
- .ccid_hc_tx_send_packet = ccid2_hc_tx_send_packet,
- .ccid_hc_tx_packet_sent = ccid2_hc_tx_packet_sent,
- .ccid_hc_tx_parse_options = ccid2_hc_tx_parse_options,
- .ccid_hc_tx_packet_recv = ccid2_hc_tx_packet_recv,
- .ccid_hc_rx_obj_size = sizeof(struct ccid2_hc_rx_sock),
- .ccid_hc_rx_packet_recv = ccid2_hc_rx_packet_recv,
- };
- #ifdef CONFIG_IP_DCCP_CCID2_DEBUG
- module_param(ccid2_debug, bool, 0644);
- MODULE_PARM_DESC(ccid2_debug, "Enable CCID-2 debug messages");
- #endif
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