| /* |
| * 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 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) |
| { |
| struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk); |
| |
| if (hc->tx_pipe < hc->tx_cwnd) |
| return 0; |
| |
| return 1; /* XXX CCID should dequeue when ready instead of polling */ |
| } |
| |
| static void ccid2_change_l_ack_ratio(struct sock *sk, u32 val) |
| { |
| struct dccp_sock *dp = dccp_sk(sk); |
| 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; |
| } |
| if (val > DCCPF_ACK_RATIO_MAX) |
| val = DCCPF_ACK_RATIO_MAX; |
| |
| if (val == dp->dccps_l_ack_ratio) |
| return; |
| |
| ccid2_pr_debug("changing local ack ratio to %u\n", val); |
| dp->dccps_l_ack_ratio = val; |
| } |
| |
| 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); |
| |
| 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; |
| |
| sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + hc->tx_rto); |
| |
| /* 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); |
| out: |
| bh_unlock_sock(sk); |
| sock_put(sk); |
| } |
| |
| static void ccid2_hc_tx_packet_sent(struct sock *sk, int more, unsigned int len) |
| { |
| struct dccp_sock *dp = dccp_sk(sk); |
| struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk); |
| struct ccid2_seq *next; |
| |
| hc->tx_pipe++; |
| |
| hc->tx_seqh->ccid2s_seq = dp->dccps_gss; |
| hc->tx_seqh->ccid2s_acked = 0; |
| hc->tx_seqh->ccid2s_sent = ccid2_time_stamp; |
| |
| 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 |
| } |
| |
| /* XXX Lame code duplication! |
| * returns -1 if none was found. |
| * else returns the next offset to use in the function call. |
| */ |
| static int ccid2_ackvector(struct sock *sk, struct sk_buff *skb, int offset, |
| unsigned char **vec, unsigned char *veclen) |
| { |
| const struct dccp_hdr *dh = dccp_hdr(skb); |
| unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb); |
| unsigned char *opt_ptr; |
| const unsigned char *opt_end = (unsigned char *)dh + |
| (dh->dccph_doff * 4); |
| unsigned char opt, len; |
| unsigned char *value; |
| |
| BUG_ON(offset < 0); |
| options += offset; |
| opt_ptr = options; |
| if (opt_ptr >= opt_end) |
| return -1; |
| |
| while (opt_ptr != opt_end) { |
| opt = *opt_ptr++; |
| len = 0; |
| value = NULL; |
| |
| /* Check if this isn't a single byte option */ |
| if (opt > DCCPO_MAX_RESERVED) { |
| if (opt_ptr == opt_end) |
| goto out_invalid_option; |
| |
| len = *opt_ptr++; |
| if (len < 3) |
| goto out_invalid_option; |
| /* |
| * Remove the type and len fields, leaving |
| * just the value size |
| */ |
| len -= 2; |
| value = opt_ptr; |
| opt_ptr += len; |
| |
| if (opt_ptr > opt_end) |
| goto out_invalid_option; |
| } |
| |
| switch (opt) { |
| case DCCPO_ACK_VECTOR_0: |
| case DCCPO_ACK_VECTOR_1: |
| *vec = value; |
| *veclen = len; |
| return offset + (opt_ptr - options); |
| } |
| } |
| |
| return -1; |
| |
| out_invalid_option: |
| DCCP_BUG("Invalid option - this should not happen (previous parsing)!"); |
| return -1; |
| } |
| |
| /** |
| * 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); |
| |
| 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; |
| } |
| /* |
| * 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 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); |
| u64 ackno, seqno; |
| struct ccid2_seq *seqp; |
| unsigned char *vector; |
| unsigned char veclen; |
| int offset = 0; |
| 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; |
| |
| ccid2_change_l_ack_ratio(sk, 2 * dp->dccps_l_ack_ratio); |
| } |
| } |
| } |
| |
| /* check forward path congestion */ |
| /* still didn't send out new data packets */ |
| if (hc->tx_seqh == hc->tx_seqt) |
| return; |
| |
| switch (DCCP_SKB_CB(skb)->dccpd_type) { |
| case DCCP_PKT_ACK: |
| case DCCP_PKT_DATAACK: |
| break; |
| default: |
| return; |
| } |
| |
| 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 */ |
| while ((offset = ccid2_ackvector(sk, skb, offset, |
| &vector, &veclen)) != -1) { |
| /* go through this ack vector */ |
| while (veclen--) { |
| const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK; |
| u64 ackno_end_rl = SUB48(ackno, rl); |
| |
| ccid2_pr_debug("ackvec start:%llu end:%llu\n", |
| (unsigned long long)ackno, |
| (unsigned long long)ackno_end_rl); |
| /* 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 = *vector & |
| DCCP_ACKVEC_STATE_MASK; |
| |
| /* new packet received or marked */ |
| if (state != DCCP_ACKVEC_STATE_NOT_RECEIVED && |
| !seqp->ccid2s_acked) { |
| if (state == |
| DCCP_ACKVEC_STATE_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); |
| vector++; |
| } |
| 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); |
| } |
| |
| 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); |
| |
| /* 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 = ccid2_time_stamp; |
| setup_timer(&hc->tx_rtotimer, ccid2_hc_tx_rto_expire, |
| (unsigned long)sk); |
| 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) |
| { |
| const struct dccp_sock *dp = dccp_sk(sk); |
| struct ccid2_hc_rx_sock *hc = ccid2_hc_rx_sk(sk); |
| |
| switch (DCCP_SKB_CB(skb)->dccpd_type) { |
| case DCCP_PKT_DATA: |
| case DCCP_PKT_DATAACK: |
| hc->rx_data++; |
| if (hc->rx_data >= dp->dccps_r_ack_ratio) { |
| dccp_send_ack(sk); |
| hc->rx_data = 0; |
| } |
| break; |
| } |
| } |
| |
| 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_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 |