![Gerrit Renker](/assets/img/avatar_default.png)
This removes a redundancy in the CCID half-connection (hc) naming scheme: * instead of 'hctx->tx_...', write 'hc->tx_...'; * instead of 'hcrx->rx_...', write 'hc->rx_...'; which works because the 'type' of the half-connection is encoded in the 'rx_' / 'tx_' prefixes. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
783 lines
20 KiB
C
783 lines
20 KiB
C
/*
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* Copyright (c) 2005, 2006 Andrea Bittau <a.bittau@cs.ucl.ac.uk>
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*
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* Changes to meet Linux coding standards, and DCCP infrastructure fixes.
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*
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* Copyright (c) 2006 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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/*
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* This implementation should follow RFC 4341
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*/
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#include "../feat.h"
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#include "../ccid.h"
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#include "../dccp.h"
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#include "ccid2.h"
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#ifdef CONFIG_IP_DCCP_CCID2_DEBUG
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static int ccid2_debug;
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#define ccid2_pr_debug(format, a...) DCCP_PR_DEBUG(ccid2_debug, format, ##a)
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static void ccid2_hc_tx_check_sanity(const struct ccid2_hc_tx_sock *hc)
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{
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int len = 0;
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int pipe = 0;
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struct ccid2_seq *seqp = hc->tx_seqh;
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/* there is data in the chain */
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if (seqp != hc->tx_seqt) {
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seqp = seqp->ccid2s_prev;
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len++;
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if (!seqp->ccid2s_acked)
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pipe++;
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while (seqp != hc->tx_seqt) {
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struct ccid2_seq *prev = seqp->ccid2s_prev;
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len++;
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if (!prev->ccid2s_acked)
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pipe++;
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/* packets are sent sequentially */
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BUG_ON(dccp_delta_seqno(seqp->ccid2s_seq,
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prev->ccid2s_seq ) >= 0);
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BUG_ON(time_before(seqp->ccid2s_sent,
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prev->ccid2s_sent));
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seqp = prev;
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}
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}
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BUG_ON(pipe != hc->tx_pipe);
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ccid2_pr_debug("len of chain=%d\n", len);
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do {
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seqp = seqp->ccid2s_prev;
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len++;
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} while (seqp != hc->tx_seqh);
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ccid2_pr_debug("total len=%d\n", len);
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BUG_ON(len != hc->tx_seqbufc * CCID2_SEQBUF_LEN);
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}
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#else
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#define ccid2_pr_debug(format, a...)
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#define ccid2_hc_tx_check_sanity(hc)
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#endif
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static int ccid2_hc_tx_alloc_seq(struct ccid2_hc_tx_sock *hc)
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{
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struct ccid2_seq *seqp;
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int i;
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/* check if we have space to preserve the pointer to the buffer */
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if (hc->tx_seqbufc >= (sizeof(hc->tx_seqbuf) /
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sizeof(struct ccid2_seq *)))
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return -ENOMEM;
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/* allocate buffer and initialize linked list */
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seqp = kmalloc(CCID2_SEQBUF_LEN * sizeof(struct ccid2_seq), gfp_any());
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if (seqp == NULL)
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return -ENOMEM;
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for (i = 0; i < (CCID2_SEQBUF_LEN - 1); i++) {
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seqp[i].ccid2s_next = &seqp[i + 1];
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seqp[i + 1].ccid2s_prev = &seqp[i];
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}
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seqp[CCID2_SEQBUF_LEN - 1].ccid2s_next = seqp;
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seqp->ccid2s_prev = &seqp[CCID2_SEQBUF_LEN - 1];
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/* This is the first allocation. Initiate the head and tail. */
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if (hc->tx_seqbufc == 0)
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hc->tx_seqh = hc->tx_seqt = seqp;
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else {
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/* link the existing list with the one we just created */
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hc->tx_seqh->ccid2s_next = seqp;
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seqp->ccid2s_prev = hc->tx_seqh;
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hc->tx_seqt->ccid2s_prev = &seqp[CCID2_SEQBUF_LEN - 1];
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seqp[CCID2_SEQBUF_LEN - 1].ccid2s_next = hc->tx_seqt;
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}
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/* store the original pointer to the buffer so we can free it */
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hc->tx_seqbuf[hc->tx_seqbufc] = seqp;
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hc->tx_seqbufc++;
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return 0;
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}
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static int ccid2_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
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{
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struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
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if (hc->tx_pipe < hc->tx_cwnd)
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return 0;
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return 1; /* XXX CCID should dequeue when ready instead of polling */
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}
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static void ccid2_change_l_ack_ratio(struct sock *sk, u32 val)
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{
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struct dccp_sock *dp = dccp_sk(sk);
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u32 max_ratio = DIV_ROUND_UP(ccid2_hc_tx_sk(sk)->tx_cwnd, 2);
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/*
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* Ensure that Ack Ratio does not exceed ceil(cwnd/2), which is (2) from
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* RFC 4341, 6.1.2. We ignore the statement that Ack Ratio 2 is always
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* acceptable since this causes starvation/deadlock whenever cwnd < 2.
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* The same problem arises when Ack Ratio is 0 (ie. Ack Ratio disabled).
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*/
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if (val == 0 || val > max_ratio) {
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DCCP_WARN("Limiting Ack Ratio (%u) to %u\n", val, max_ratio);
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val = max_ratio;
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}
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if (val > DCCPF_ACK_RATIO_MAX)
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val = DCCPF_ACK_RATIO_MAX;
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if (val == dp->dccps_l_ack_ratio)
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return;
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ccid2_pr_debug("changing local ack ratio to %u\n", val);
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dp->dccps_l_ack_ratio = val;
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}
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static void ccid2_change_srtt(struct ccid2_hc_tx_sock *hc, long val)
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{
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ccid2_pr_debug("change SRTT to %ld\n", val);
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hc->tx_srtt = val;
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}
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static void ccid2_start_rto_timer(struct sock *sk);
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static void ccid2_hc_tx_rto_expire(unsigned long data)
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{
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struct sock *sk = (struct sock *)data;
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struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
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long s;
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bh_lock_sock(sk);
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if (sock_owned_by_user(sk)) {
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sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + HZ / 5);
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goto out;
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}
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ccid2_pr_debug("RTO_EXPIRE\n");
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ccid2_hc_tx_check_sanity(hc);
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/* back-off timer */
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hc->tx_rto <<= 1;
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s = hc->tx_rto / HZ;
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if (s > 60)
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hc->tx_rto = 60 * HZ;
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ccid2_start_rto_timer(sk);
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/* adjust pipe, cwnd etc */
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hc->tx_ssthresh = hc->tx_cwnd / 2;
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if (hc->tx_ssthresh < 2)
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hc->tx_ssthresh = 2;
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hc->tx_cwnd = 1;
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hc->tx_pipe = 0;
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/* clear state about stuff we sent */
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hc->tx_seqt = hc->tx_seqh;
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hc->tx_packets_acked = 0;
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/* clear ack ratio state. */
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hc->tx_rpseq = 0;
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hc->tx_rpdupack = -1;
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ccid2_change_l_ack_ratio(sk, 1);
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ccid2_hc_tx_check_sanity(hc);
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out:
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bh_unlock_sock(sk);
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sock_put(sk);
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}
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static void ccid2_start_rto_timer(struct sock *sk)
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{
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struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
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ccid2_pr_debug("setting RTO timeout=%ld\n", hc->tx_rto);
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BUG_ON(timer_pending(&hc->tx_rtotimer));
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sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + hc->tx_rto);
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}
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static void ccid2_hc_tx_packet_sent(struct sock *sk, int more, unsigned int len)
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{
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struct dccp_sock *dp = dccp_sk(sk);
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struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
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struct ccid2_seq *next;
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hc->tx_pipe++;
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hc->tx_seqh->ccid2s_seq = dp->dccps_gss;
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hc->tx_seqh->ccid2s_acked = 0;
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hc->tx_seqh->ccid2s_sent = jiffies;
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next = hc->tx_seqh->ccid2s_next;
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/* check if we need to alloc more space */
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if (next == hc->tx_seqt) {
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if (ccid2_hc_tx_alloc_seq(hc)) {
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DCCP_CRIT("packet history - out of memory!");
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/* FIXME: find a more graceful way to bail out */
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return;
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}
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next = hc->tx_seqh->ccid2s_next;
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BUG_ON(next == hc->tx_seqt);
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}
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hc->tx_seqh = next;
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ccid2_pr_debug("cwnd=%d pipe=%d\n", hc->tx_cwnd, hc->tx_pipe);
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/*
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* FIXME: The code below is broken and the variables have been removed
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* from the socket struct. The `ackloss' variable was always set to 0,
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* and with arsent there are several problems:
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* (i) it doesn't just count the number of Acks, but all sent packets;
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* (ii) it is expressed in # of packets, not # of windows, so the
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* comparison below uses the wrong formula: Appendix A of RFC 4341
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* comes up with the number K = cwnd / (R^2 - R) of consecutive windows
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* of data with no lost or marked Ack packets. If arsent were the # of
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* consecutive Acks received without loss, then Ack Ratio needs to be
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* decreased by 1 when
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* arsent >= K * cwnd / R = cwnd^2 / (R^3 - R^2)
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* where cwnd / R is the number of Acks received per window of data
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* (cf. RFC 4341, App. A). The problems are that
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* - arsent counts other packets as well;
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* - the comparison uses a formula different from RFC 4341;
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* - computing a cubic/quadratic equation each time is too complicated.
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* Hence a different algorithm is needed.
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*/
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#if 0
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/* Ack Ratio. Need to maintain a concept of how many windows we sent */
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hc->tx_arsent++;
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/* We had an ack loss in this window... */
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if (hc->tx_ackloss) {
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if (hc->tx_arsent >= hc->tx_cwnd) {
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hc->tx_arsent = 0;
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hc->tx_ackloss = 0;
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}
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} else {
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/* No acks lost up to now... */
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/* decrease ack ratio if enough packets were sent */
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if (dp->dccps_l_ack_ratio > 1) {
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/* XXX don't calculate denominator each time */
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int denom = dp->dccps_l_ack_ratio * dp->dccps_l_ack_ratio -
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dp->dccps_l_ack_ratio;
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denom = hc->tx_cwnd * hc->tx_cwnd / denom;
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if (hc->tx_arsent >= denom) {
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ccid2_change_l_ack_ratio(sk, dp->dccps_l_ack_ratio - 1);
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hc->tx_arsent = 0;
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}
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} else {
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/* we can't increase ack ratio further [1] */
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hc->tx_arsent = 0; /* or maybe set it to cwnd*/
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}
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}
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#endif
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/* setup RTO timer */
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if (!timer_pending(&hc->tx_rtotimer))
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ccid2_start_rto_timer(sk);
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#ifdef CONFIG_IP_DCCP_CCID2_DEBUG
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do {
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struct ccid2_seq *seqp = hc->tx_seqt;
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while (seqp != hc->tx_seqh) {
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ccid2_pr_debug("out seq=%llu acked=%d time=%lu\n",
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(unsigned long long)seqp->ccid2s_seq,
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seqp->ccid2s_acked, seqp->ccid2s_sent);
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seqp = seqp->ccid2s_next;
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}
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} while (0);
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ccid2_pr_debug("=========\n");
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ccid2_hc_tx_check_sanity(hc);
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#endif
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}
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/* XXX Lame code duplication!
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* returns -1 if none was found.
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* else returns the next offset to use in the function call.
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*/
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static int ccid2_ackvector(struct sock *sk, struct sk_buff *skb, int offset,
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unsigned char **vec, unsigned char *veclen)
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{
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const struct dccp_hdr *dh = dccp_hdr(skb);
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unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb);
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unsigned char *opt_ptr;
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const unsigned char *opt_end = (unsigned char *)dh +
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(dh->dccph_doff * 4);
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unsigned char opt, len;
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unsigned char *value;
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BUG_ON(offset < 0);
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options += offset;
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opt_ptr = options;
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if (opt_ptr >= opt_end)
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return -1;
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while (opt_ptr != opt_end) {
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opt = *opt_ptr++;
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len = 0;
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value = NULL;
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/* Check if this isn't a single byte option */
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if (opt > DCCPO_MAX_RESERVED) {
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if (opt_ptr == opt_end)
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goto out_invalid_option;
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len = *opt_ptr++;
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if (len < 3)
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goto out_invalid_option;
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/*
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* Remove the type and len fields, leaving
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* just the value size
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*/
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len -= 2;
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value = opt_ptr;
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opt_ptr += len;
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if (opt_ptr > opt_end)
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goto out_invalid_option;
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}
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switch (opt) {
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case DCCPO_ACK_VECTOR_0:
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case DCCPO_ACK_VECTOR_1:
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*vec = value;
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*veclen = len;
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return offset + (opt_ptr - options);
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}
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}
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return -1;
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out_invalid_option:
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DCCP_BUG("Invalid option - this should not happen (previous parsing)!");
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return -1;
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}
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static void ccid2_hc_tx_kill_rto_timer(struct sock *sk)
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{
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struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
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sk_stop_timer(sk, &hc->tx_rtotimer);
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ccid2_pr_debug("deleted RTO timer\n");
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}
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static inline void ccid2_new_ack(struct sock *sk,
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struct ccid2_seq *seqp,
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unsigned int *maxincr)
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{
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struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
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if (hc->tx_cwnd < hc->tx_ssthresh) {
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if (*maxincr > 0 && ++hc->tx_packets_acked == 2) {
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hc->tx_cwnd += 1;
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*maxincr -= 1;
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hc->tx_packets_acked = 0;
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}
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} else if (++hc->tx_packets_acked >= hc->tx_cwnd) {
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hc->tx_cwnd += 1;
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hc->tx_packets_acked = 0;
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}
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/* update RTO */
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if (hc->tx_srtt == -1 ||
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time_after(jiffies, hc->tx_lastrtt + hc->tx_srtt)) {
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unsigned long r = (long)jiffies - (long)seqp->ccid2s_sent;
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int s;
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/* first measurement */
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if (hc->tx_srtt == -1) {
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ccid2_pr_debug("R: %lu Time=%lu seq=%llu\n",
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r, jiffies,
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(unsigned long long)seqp->ccid2s_seq);
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ccid2_change_srtt(hc, r);
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hc->tx_rttvar = r >> 1;
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} else {
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/* RTTVAR */
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long tmp = hc->tx_srtt - r;
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long srtt;
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if (tmp < 0)
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tmp *= -1;
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tmp >>= 2;
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hc->tx_rttvar *= 3;
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hc->tx_rttvar >>= 2;
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hc->tx_rttvar += tmp;
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/* SRTT */
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srtt = hc->tx_srtt;
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srtt *= 7;
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srtt >>= 3;
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tmp = r >> 3;
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srtt += tmp;
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ccid2_change_srtt(hc, srtt);
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}
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s = hc->tx_rttvar << 2;
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/* clock granularity is 1 when based on jiffies */
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if (!s)
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s = 1;
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hc->tx_rto = hc->tx_srtt + s;
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/* must be at least a second */
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s = hc->tx_rto / HZ;
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/* DCCP doesn't require this [but I like it cuz my code sux] */
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#if 1
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if (s < 1)
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hc->tx_rto = HZ;
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#endif
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/* max 60 seconds */
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if (s > 60)
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hc->tx_rto = HZ * 60;
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hc->tx_lastrtt = jiffies;
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ccid2_pr_debug("srtt: %ld rttvar: %ld rto: %ld (HZ=%d) R=%lu\n",
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hc->tx_srtt, hc->tx_rttvar,
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hc->tx_rto, HZ, r);
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}
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/* we got a new ack, so re-start RTO timer */
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ccid2_hc_tx_kill_rto_timer(sk);
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ccid2_start_rto_timer(sk);
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}
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static void ccid2_hc_tx_dec_pipe(struct sock *sk)
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{
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struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
|
|
|
|
if (hc->tx_pipe == 0)
|
|
DCCP_BUG("pipe == 0");
|
|
else
|
|
hc->tx_pipe--;
|
|
|
|
if (hc->tx_pipe == 0)
|
|
ccid2_hc_tx_kill_rto_timer(sk);
|
|
}
|
|
|
|
static void ccid2_congestion_event(struct sock *sk, struct ccid2_seq *seqp)
|
|
{
|
|
struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
|
|
|
|
if (time_before(seqp->ccid2s_sent, hc->tx_last_cong)) {
|
|
ccid2_pr_debug("Multiple losses in an RTT---treating as one\n");
|
|
return;
|
|
}
|
|
|
|
hc->tx_last_cong = jiffies;
|
|
|
|
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;
|
|
|
|
ccid2_hc_tx_check_sanity(hc);
|
|
/* 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);
|
|
ccid2_hc_tx_dec_pipe(sk);
|
|
}
|
|
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);
|
|
ccid2_hc_tx_dec_pipe(sk);
|
|
}
|
|
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;
|
|
}
|
|
|
|
ccid2_hc_tx_check_sanity(hc);
|
|
}
|
|
|
|
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;
|
|
|
|
/*
|
|
* RFC 4341, 5: "The cwnd parameter is initialized to at most four
|
|
* packets for new connections, following the rules from [RFC3390]".
|
|
* We need to convert the bytes of RFC3390 into the packets of RFC 4341.
|
|
*/
|
|
hc->tx_cwnd = clamp(4380U / dp->dccps_mss_cache, 2U, 4U);
|
|
|
|
/* 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 = 3 * HZ;
|
|
ccid2_change_srtt(hc, -1);
|
|
hc->tx_rttvar = -1;
|
|
hc->tx_rpdupack = -1;
|
|
hc->tx_last_cong = jiffies;
|
|
setup_timer(&hc->tx_rtotimer, ccid2_hc_tx_rto_expire,
|
|
(unsigned long)sk);
|
|
|
|
ccid2_hc_tx_check_sanity(hc);
|
|
return 0;
|
|
}
|
|
|
|
static void ccid2_hc_tx_exit(struct sock *sk)
|
|
{
|
|
struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
|
|
int i;
|
|
|
|
ccid2_hc_tx_kill_rto_timer(sk);
|
|
|
|
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
|