/* * Copyright (c) 2005, 2006 Andrea Bittau * * Changes to meet Linux coding standards, and DCCP infrastructure fixes. * * Copyright (c) 2006 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. */ /* * This implementation should follow RFC 4341 */ #include #include "../feat.h" #include "ccid2.h" #ifdef CONFIG_IP_DCCP_CCID2_DEBUG static int 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_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 int ccid2_do_cwv = 1; 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; } /* 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; } 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); /* Avoid spurious timeouts resulting from Ack Ratio > cwnd */ if (dccp_sk(sk)->dccps_l_ack_ratio > hc->tx_cwnd) ccid2_change_l_ack_ratio(sk, hc->tx_cwnd); } 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