Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 1 | /* |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 2 | * Copyright (c) 2005, 2006 Andrea Bittau <a.bittau@cs.ucl.ac.uk> |
| 3 | * |
| 4 | * Changes to meet Linux coding standards, and DCCP infrastructure fixes. |
| 5 | * |
| 6 | * Copyright (c) 2006 Arnaldo Carvalho de Melo <acme@conectiva.com.br> |
| 7 | * |
| 8 | * This program is free software; you can redistribute it and/or modify |
| 9 | * it under the terms of the GNU General Public License as published by |
| 10 | * the Free Software Foundation; either version 2 of the License, or |
| 11 | * (at your option) any later version. |
| 12 | * |
| 13 | * This program is distributed in the hope that it will be useful, |
| 14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | * GNU General Public License for more details. |
| 17 | * |
| 18 | * You should have received a copy of the GNU General Public License |
| 19 | * along with this program; if not, write to the Free Software |
| 20 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
| 21 | */ |
| 22 | |
| 23 | /* |
Gerrit Renker | 0e64e94 | 2006-10-24 16:17:51 -0700 | [diff] [blame] | 24 | * This implementation should follow RFC 4341 |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 25 | */ |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 26 | #include <linux/slab.h> |
Gerrit Renker | e8ef967 | 2008-11-12 00:43:40 -0800 | [diff] [blame] | 27 | #include "../feat.h" |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 28 | #include "ccid2.h" |
| 29 | |
Gerrit Renker | 8411671 | 2006-11-20 18:26:03 -0200 | [diff] [blame] | 30 | |
| 31 | #ifdef CONFIG_IP_DCCP_CCID2_DEBUG |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 32 | static int ccid2_debug; |
Gerrit Renker | 8411671 | 2006-11-20 18:26:03 -0200 | [diff] [blame] | 33 | #define ccid2_pr_debug(format, a...) DCCP_PR_DEBUG(ccid2_debug, format, ##a) |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 34 | #else |
Gerrit Renker | 8411671 | 2006-11-20 18:26:03 -0200 | [diff] [blame] | 35 | #define ccid2_pr_debug(format, a...) |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 36 | #endif |
| 37 | |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 38 | static int ccid2_hc_tx_alloc_seq(struct ccid2_hc_tx_sock *hc) |
Andrea Bittau | 07978aa | 2006-09-19 13:13:37 -0700 | [diff] [blame] | 39 | { |
| 40 | struct ccid2_seq *seqp; |
| 41 | int i; |
| 42 | |
| 43 | /* check if we have space to preserve the pointer to the buffer */ |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 44 | if (hc->tx_seqbufc >= (sizeof(hc->tx_seqbuf) / |
| 45 | sizeof(struct ccid2_seq *))) |
Andrea Bittau | 07978aa | 2006-09-19 13:13:37 -0700 | [diff] [blame] | 46 | return -ENOMEM; |
| 47 | |
| 48 | /* allocate buffer and initialize linked list */ |
Gerrit Renker | cd1f7d3 | 2007-10-04 14:41:00 -0700 | [diff] [blame] | 49 | seqp = kmalloc(CCID2_SEQBUF_LEN * sizeof(struct ccid2_seq), gfp_any()); |
Andrea Bittau | 07978aa | 2006-09-19 13:13:37 -0700 | [diff] [blame] | 50 | if (seqp == NULL) |
| 51 | return -ENOMEM; |
| 52 | |
Gerrit Renker | cd1f7d3 | 2007-10-04 14:41:00 -0700 | [diff] [blame] | 53 | for (i = 0; i < (CCID2_SEQBUF_LEN - 1); i++) { |
Andrea Bittau | 07978aa | 2006-09-19 13:13:37 -0700 | [diff] [blame] | 54 | seqp[i].ccid2s_next = &seqp[i + 1]; |
| 55 | seqp[i + 1].ccid2s_prev = &seqp[i]; |
| 56 | } |
Gerrit Renker | cd1f7d3 | 2007-10-04 14:41:00 -0700 | [diff] [blame] | 57 | seqp[CCID2_SEQBUF_LEN - 1].ccid2s_next = seqp; |
| 58 | seqp->ccid2s_prev = &seqp[CCID2_SEQBUF_LEN - 1]; |
Andrea Bittau | 07978aa | 2006-09-19 13:13:37 -0700 | [diff] [blame] | 59 | |
| 60 | /* This is the first allocation. Initiate the head and tail. */ |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 61 | if (hc->tx_seqbufc == 0) |
| 62 | hc->tx_seqh = hc->tx_seqt = seqp; |
Andrea Bittau | 07978aa | 2006-09-19 13:13:37 -0700 | [diff] [blame] | 63 | else { |
| 64 | /* link the existing list with the one we just created */ |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 65 | hc->tx_seqh->ccid2s_next = seqp; |
| 66 | seqp->ccid2s_prev = hc->tx_seqh; |
Andrea Bittau | 07978aa | 2006-09-19 13:13:37 -0700 | [diff] [blame] | 67 | |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 68 | hc->tx_seqt->ccid2s_prev = &seqp[CCID2_SEQBUF_LEN - 1]; |
| 69 | seqp[CCID2_SEQBUF_LEN - 1].ccid2s_next = hc->tx_seqt; |
Andrea Bittau | 07978aa | 2006-09-19 13:13:37 -0700 | [diff] [blame] | 70 | } |
| 71 | |
| 72 | /* store the original pointer to the buffer so we can free it */ |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 73 | hc->tx_seqbuf[hc->tx_seqbufc] = seqp; |
| 74 | hc->tx_seqbufc++; |
Andrea Bittau | 07978aa | 2006-09-19 13:13:37 -0700 | [diff] [blame] | 75 | |
| 76 | return 0; |
| 77 | } |
| 78 | |
Gerrit Renker | 6b57c93 | 2006-11-28 19:55:06 -0200 | [diff] [blame] | 79 | static int ccid2_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb) |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 80 | { |
Gerrit Renker | 1c0e0a0 | 2010-10-27 19:16:28 +0000 | [diff] [blame] | 81 | if (ccid2_cwnd_network_limited(ccid2_hc_tx_sk(sk))) |
| 82 | return CCID_PACKET_WILL_DEQUEUE_LATER; |
| 83 | return CCID_PACKET_SEND_AT_ONCE; |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 84 | } |
| 85 | |
Gerrit Renker | df054e1 | 2007-11-24 21:32:53 -0200 | [diff] [blame] | 86 | static void ccid2_change_l_ack_ratio(struct sock *sk, u32 val) |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 87 | { |
| 88 | struct dccp_sock *dp = dccp_sk(sk); |
Gerrit Renker | b1c00fe | 2009-10-05 00:53:10 +0000 | [diff] [blame] | 89 | u32 max_ratio = DIV_ROUND_UP(ccid2_hc_tx_sk(sk)->tx_cwnd, 2); |
Gerrit Renker | d50ad16 | 2007-11-24 21:40:24 -0200 | [diff] [blame] | 90 | |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 91 | /* |
Gerrit Renker | d50ad16 | 2007-11-24 21:40:24 -0200 | [diff] [blame] | 92 | * Ensure that Ack Ratio does not exceed ceil(cwnd/2), which is (2) from |
| 93 | * RFC 4341, 6.1.2. We ignore the statement that Ack Ratio 2 is always |
| 94 | * acceptable since this causes starvation/deadlock whenever cwnd < 2. |
| 95 | * The same problem arises when Ack Ratio is 0 (ie. Ack Ratio disabled). |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 96 | */ |
Gerrit Renker | d50ad16 | 2007-11-24 21:40:24 -0200 | [diff] [blame] | 97 | if (val == 0 || val > max_ratio) { |
| 98 | DCCP_WARN("Limiting Ack Ratio (%u) to %u\n", val, max_ratio); |
| 99 | val = max_ratio; |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 100 | } |
Gerrit Renker | e8ef967 | 2008-11-12 00:43:40 -0800 | [diff] [blame] | 101 | if (val > DCCPF_ACK_RATIO_MAX) |
| 102 | val = DCCPF_ACK_RATIO_MAX; |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 103 | |
Gerrit Renker | d50ad16 | 2007-11-24 21:40:24 -0200 | [diff] [blame] | 104 | if (val == dp->dccps_l_ack_ratio) |
| 105 | return; |
| 106 | |
Gerrit Renker | df054e1 | 2007-11-24 21:32:53 -0200 | [diff] [blame] | 107 | ccid2_pr_debug("changing local ack ratio to %u\n", val); |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 108 | dp->dccps_l_ack_ratio = val; |
| 109 | } |
| 110 | |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 111 | static void ccid2_hc_tx_rto_expire(unsigned long data) |
| 112 | { |
| 113 | struct sock *sk = (struct sock *)data; |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 114 | struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk); |
Gerrit Renker | 1c0e0a0 | 2010-10-27 19:16:28 +0000 | [diff] [blame] | 115 | const bool sender_was_blocked = ccid2_cwnd_network_limited(hc); |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 116 | |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 117 | bh_lock_sock(sk); |
| 118 | if (sock_owned_by_user(sk)) { |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 119 | sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + HZ / 5); |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 120 | goto out; |
| 121 | } |
| 122 | |
| 123 | ccid2_pr_debug("RTO_EXPIRE\n"); |
| 124 | |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 125 | /* back-off timer */ |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 126 | hc->tx_rto <<= 1; |
Gerrit Renker | 231cc2a | 2010-08-22 19:41:40 +0000 | [diff] [blame] | 127 | if (hc->tx_rto > DCCP_RTO_MAX) |
| 128 | hc->tx_rto = DCCP_RTO_MAX; |
Gerrit Renker | 410e27a | 2008-09-09 13:27:22 +0200 | [diff] [blame] | 129 | |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 130 | /* adjust pipe, cwnd etc */ |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 131 | hc->tx_ssthresh = hc->tx_cwnd / 2; |
| 132 | if (hc->tx_ssthresh < 2) |
| 133 | hc->tx_ssthresh = 2; |
Gerrit Renker | 67b67e3 | 2010-08-22 19:41:36 +0000 | [diff] [blame] | 134 | hc->tx_cwnd = 1; |
| 135 | hc->tx_pipe = 0; |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 136 | |
| 137 | /* clear state about stuff we sent */ |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 138 | hc->tx_seqt = hc->tx_seqh; |
| 139 | hc->tx_packets_acked = 0; |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 140 | |
| 141 | /* clear ack ratio state. */ |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 142 | hc->tx_rpseq = 0; |
| 143 | hc->tx_rpdupack = -1; |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 144 | ccid2_change_l_ack_ratio(sk, 1); |
Gerrit Renker | 1c0e0a0 | 2010-10-27 19:16:28 +0000 | [diff] [blame] | 145 | |
| 146 | /* if we were blocked before, we may now send cwnd=1 packet */ |
| 147 | if (sender_was_blocked) |
| 148 | tasklet_schedule(&dccp_sk(sk)->dccps_xmitlet); |
| 149 | /* restart backed-off timer */ |
| 150 | sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + hc->tx_rto); |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 151 | out: |
| 152 | bh_unlock_sock(sk); |
Andrea Bittau | 77ff72d | 2006-03-20 17:57:52 -0800 | [diff] [blame] | 153 | sock_put(sk); |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 154 | } |
| 155 | |
Gerrit Renker | 113ced1 | 2011-07-03 09:55:03 -0600 | [diff] [blame] | 156 | /* |
| 157 | * Congestion window validation (RFC 2861). |
| 158 | */ |
| 159 | static int ccid2_do_cwv = 1; |
| 160 | module_param(ccid2_do_cwv, bool, 0644); |
| 161 | MODULE_PARM_DESC(ccid2_do_cwv, "Perform RFC2861 Congestion Window Validation"); |
| 162 | |
| 163 | /** |
| 164 | * ccid2_update_used_window - Track how much of cwnd is actually used |
| 165 | * This is done in addition to CWV. The sender needs to have an idea of how many |
| 166 | * packets may be in flight, to set the local Sequence Window value accordingly |
| 167 | * (RFC 4340, 7.5.2). The CWV mechanism is exploited to keep track of the |
| 168 | * maximum-used window. We use an EWMA low-pass filter to filter out noise. |
| 169 | */ |
| 170 | static void ccid2_update_used_window(struct ccid2_hc_tx_sock *hc, u32 new_wnd) |
| 171 | { |
| 172 | hc->tx_expected_wnd = (3 * hc->tx_expected_wnd + new_wnd) / 4; |
| 173 | } |
| 174 | |
| 175 | /* This borrows the code of tcp_cwnd_application_limited() */ |
| 176 | static void ccid2_cwnd_application_limited(struct sock *sk, const u32 now) |
| 177 | { |
| 178 | struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk); |
| 179 | /* don't reduce cwnd below the initial window (IW) */ |
| 180 | u32 init_win = rfc3390_bytes_to_packets(dccp_sk(sk)->dccps_mss_cache), |
| 181 | win_used = max(hc->tx_cwnd_used, init_win); |
| 182 | |
| 183 | if (win_used < hc->tx_cwnd) { |
| 184 | hc->tx_ssthresh = max(hc->tx_ssthresh, |
| 185 | (hc->tx_cwnd >> 1) + (hc->tx_cwnd >> 2)); |
| 186 | hc->tx_cwnd = (hc->tx_cwnd + win_used) >> 1; |
| 187 | } |
| 188 | hc->tx_cwnd_used = 0; |
| 189 | hc->tx_cwnd_stamp = now; |
| 190 | } |
| 191 | |
| 192 | /* This borrows the code of tcp_cwnd_restart() */ |
| 193 | static void ccid2_cwnd_restart(struct sock *sk, const u32 now) |
| 194 | { |
| 195 | struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk); |
| 196 | u32 cwnd = hc->tx_cwnd, restart_cwnd, |
| 197 | iwnd = rfc3390_bytes_to_packets(dccp_sk(sk)->dccps_mss_cache); |
| 198 | |
| 199 | hc->tx_ssthresh = max(hc->tx_ssthresh, (cwnd >> 1) + (cwnd >> 2)); |
| 200 | |
| 201 | /* don't reduce cwnd below the initial window (IW) */ |
| 202 | restart_cwnd = min(cwnd, iwnd); |
| 203 | cwnd >>= (now - hc->tx_lsndtime) / hc->tx_rto; |
| 204 | hc->tx_cwnd = max(cwnd, restart_cwnd); |
| 205 | |
| 206 | hc->tx_cwnd_stamp = now; |
| 207 | hc->tx_cwnd_used = 0; |
| 208 | } |
| 209 | |
Gerrit Renker | baf9e78 | 2010-10-11 20:37:38 +0200 | [diff] [blame] | 210 | static void ccid2_hc_tx_packet_sent(struct sock *sk, unsigned int len) |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 211 | { |
| 212 | struct dccp_sock *dp = dccp_sk(sk); |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 213 | struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk); |
Gerrit Renker | 113ced1 | 2011-07-03 09:55:03 -0600 | [diff] [blame] | 214 | const u32 now = ccid2_time_stamp; |
Andrea Bittau | 07978aa | 2006-09-19 13:13:37 -0700 | [diff] [blame] | 215 | struct ccid2_seq *next; |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 216 | |
Gerrit Renker | 113ced1 | 2011-07-03 09:55:03 -0600 | [diff] [blame] | 217 | /* slow-start after idle periods (RFC 2581, RFC 2861) */ |
| 218 | if (ccid2_do_cwv && !hc->tx_pipe && |
| 219 | (s32)(now - hc->tx_lsndtime) >= hc->tx_rto) |
| 220 | ccid2_cwnd_restart(sk, now); |
| 221 | |
| 222 | hc->tx_lsndtime = now; |
| 223 | hc->tx_pipe += 1; |
| 224 | |
| 225 | /* see whether cwnd was fully used (RFC 2861), update expected window */ |
| 226 | if (ccid2_cwnd_network_limited(hc)) { |
| 227 | ccid2_update_used_window(hc, hc->tx_cwnd); |
| 228 | hc->tx_cwnd_used = 0; |
| 229 | hc->tx_cwnd_stamp = now; |
| 230 | } else { |
| 231 | if (hc->tx_pipe > hc->tx_cwnd_used) |
| 232 | hc->tx_cwnd_used = hc->tx_pipe; |
| 233 | |
| 234 | ccid2_update_used_window(hc, hc->tx_cwnd_used); |
| 235 | |
| 236 | if (ccid2_do_cwv && (s32)(now - hc->tx_cwnd_stamp) >= hc->tx_rto) |
| 237 | ccid2_cwnd_application_limited(sk, now); |
| 238 | } |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 239 | |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 240 | hc->tx_seqh->ccid2s_seq = dp->dccps_gss; |
| 241 | hc->tx_seqh->ccid2s_acked = 0; |
Gerrit Renker | 113ced1 | 2011-07-03 09:55:03 -0600 | [diff] [blame] | 242 | hc->tx_seqh->ccid2s_sent = now; |
Andrea Bittau | 07978aa | 2006-09-19 13:13:37 -0700 | [diff] [blame] | 243 | |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 244 | next = hc->tx_seqh->ccid2s_next; |
Andrea Bittau | 07978aa | 2006-09-19 13:13:37 -0700 | [diff] [blame] | 245 | /* check if we need to alloc more space */ |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 246 | if (next == hc->tx_seqt) { |
| 247 | if (ccid2_hc_tx_alloc_seq(hc)) { |
Gerrit Renker | 7d9e893 | 2007-10-04 14:41:26 -0700 | [diff] [blame] | 248 | DCCP_CRIT("packet history - out of memory!"); |
| 249 | /* FIXME: find a more graceful way to bail out */ |
| 250 | return; |
| 251 | } |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 252 | next = hc->tx_seqh->ccid2s_next; |
| 253 | BUG_ON(next == hc->tx_seqt); |
Andrea Bittau | 07978aa | 2006-09-19 13:13:37 -0700 | [diff] [blame] | 254 | } |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 255 | hc->tx_seqh = next; |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 256 | |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 257 | ccid2_pr_debug("cwnd=%d pipe=%d\n", hc->tx_cwnd, hc->tx_pipe); |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 258 | |
Gerrit Renker | 900bfed | 2007-11-24 21:58:33 -0200 | [diff] [blame] | 259 | /* |
| 260 | * FIXME: The code below is broken and the variables have been removed |
| 261 | * from the socket struct. The `ackloss' variable was always set to 0, |
| 262 | * and with arsent there are several problems: |
| 263 | * (i) it doesn't just count the number of Acks, but all sent packets; |
| 264 | * (ii) it is expressed in # of packets, not # of windows, so the |
| 265 | * comparison below uses the wrong formula: Appendix A of RFC 4341 |
| 266 | * comes up with the number K = cwnd / (R^2 - R) of consecutive windows |
| 267 | * of data with no lost or marked Ack packets. If arsent were the # of |
| 268 | * consecutive Acks received without loss, then Ack Ratio needs to be |
| 269 | * decreased by 1 when |
| 270 | * arsent >= K * cwnd / R = cwnd^2 / (R^3 - R^2) |
| 271 | * where cwnd / R is the number of Acks received per window of data |
| 272 | * (cf. RFC 4341, App. A). The problems are that |
| 273 | * - arsent counts other packets as well; |
| 274 | * - the comparison uses a formula different from RFC 4341; |
| 275 | * - computing a cubic/quadratic equation each time is too complicated. |
| 276 | * Hence a different algorithm is needed. |
| 277 | */ |
| 278 | #if 0 |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 279 | /* Ack Ratio. Need to maintain a concept of how many windows we sent */ |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 280 | hc->tx_arsent++; |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 281 | /* We had an ack loss in this window... */ |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 282 | if (hc->tx_ackloss) { |
| 283 | if (hc->tx_arsent >= hc->tx_cwnd) { |
| 284 | hc->tx_arsent = 0; |
| 285 | hc->tx_ackloss = 0; |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 286 | } |
Arnaldo Carvalho de Melo | c0c736d | 2006-03-20 22:05:37 -0800 | [diff] [blame] | 287 | } else { |
| 288 | /* No acks lost up to now... */ |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 289 | /* decrease ack ratio if enough packets were sent */ |
| 290 | if (dp->dccps_l_ack_ratio > 1) { |
| 291 | /* XXX don't calculate denominator each time */ |
Arnaldo Carvalho de Melo | c0c736d | 2006-03-20 22:05:37 -0800 | [diff] [blame] | 292 | int denom = dp->dccps_l_ack_ratio * dp->dccps_l_ack_ratio - |
| 293 | dp->dccps_l_ack_ratio; |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 294 | |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 295 | denom = hc->tx_cwnd * hc->tx_cwnd / denom; |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 296 | |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 297 | if (hc->tx_arsent >= denom) { |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 298 | ccid2_change_l_ack_ratio(sk, dp->dccps_l_ack_ratio - 1); |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 299 | hc->tx_arsent = 0; |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 300 | } |
Arnaldo Carvalho de Melo | c0c736d | 2006-03-20 22:05:37 -0800 | [diff] [blame] | 301 | } else { |
| 302 | /* we can't increase ack ratio further [1] */ |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 303 | hc->tx_arsent = 0; /* or maybe set it to cwnd*/ |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 304 | } |
| 305 | } |
Gerrit Renker | 900bfed | 2007-11-24 21:58:33 -0200 | [diff] [blame] | 306 | #endif |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 307 | |
Gerrit Renker | d26eeb0 | 2010-08-29 19:23:11 +0000 | [diff] [blame] | 308 | sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + hc->tx_rto); |
Arnaldo Carvalho de Melo | c0c736d | 2006-03-20 22:05:37 -0800 | [diff] [blame] | 309 | |
Andrea Bittau | 8d424f6 | 2006-09-19 13:12:44 -0700 | [diff] [blame] | 310 | #ifdef CONFIG_IP_DCCP_CCID2_DEBUG |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 311 | do { |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 312 | struct ccid2_seq *seqp = hc->tx_seqt; |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 313 | |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 314 | while (seqp != hc->tx_seqh) { |
Gerrit Renker | d82b6f8 | 2010-08-29 19:23:10 +0000 | [diff] [blame] | 315 | ccid2_pr_debug("out seq=%llu acked=%d time=%u\n", |
Arnaldo Carvalho de Melo | 8109b02 | 2006-12-10 16:01:18 -0200 | [diff] [blame] | 316 | (unsigned long long)seqp->ccid2s_seq, |
Randy Dunlap | 234af48 | 2006-10-29 16:03:30 -0800 | [diff] [blame] | 317 | seqp->ccid2s_acked, seqp->ccid2s_sent); |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 318 | seqp = seqp->ccid2s_next; |
| 319 | } |
Arnaldo Carvalho de Melo | c0c736d | 2006-03-20 22:05:37 -0800 | [diff] [blame] | 320 | } while (0); |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 321 | ccid2_pr_debug("=========\n"); |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 322 | #endif |
| 323 | } |
| 324 | |
Gerrit Renker | 231cc2a | 2010-08-22 19:41:40 +0000 | [diff] [blame] | 325 | /** |
| 326 | * ccid2_rtt_estimator - Sample RTT and compute RTO using RFC2988 algorithm |
| 327 | * This code is almost identical with TCP's tcp_rtt_estimator(), since |
| 328 | * - it has a higher sampling frequency (recommended by RFC 1323), |
| 329 | * - the RTO does not collapse into RTT due to RTTVAR going towards zero, |
| 330 | * - it is simple (cf. more complex proposals such as Eifel timer or research |
| 331 | * which suggests that the gain should be set according to window size), |
| 332 | * - in tests it was found to work well with CCID2 [gerrit]. |
| 333 | */ |
| 334 | static void ccid2_rtt_estimator(struct sock *sk, const long mrtt) |
| 335 | { |
| 336 | struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk); |
| 337 | long m = mrtt ? : 1; |
| 338 | |
| 339 | if (hc->tx_srtt == 0) { |
| 340 | /* First measurement m */ |
| 341 | hc->tx_srtt = m << 3; |
| 342 | hc->tx_mdev = m << 1; |
| 343 | |
Gerrit Renker | 4886fca | 2010-08-29 19:23:13 +0000 | [diff] [blame] | 344 | hc->tx_mdev_max = max(hc->tx_mdev, tcp_rto_min(sk)); |
Gerrit Renker | 231cc2a | 2010-08-22 19:41:40 +0000 | [diff] [blame] | 345 | hc->tx_rttvar = hc->tx_mdev_max; |
Gerrit Renker | 4886fca | 2010-08-29 19:23:13 +0000 | [diff] [blame] | 346 | |
Gerrit Renker | 231cc2a | 2010-08-22 19:41:40 +0000 | [diff] [blame] | 347 | hc->tx_rtt_seq = dccp_sk(sk)->dccps_gss; |
| 348 | } else { |
| 349 | /* Update scaled SRTT as SRTT += 1/8 * (m - SRTT) */ |
| 350 | m -= (hc->tx_srtt >> 3); |
| 351 | hc->tx_srtt += m; |
| 352 | |
| 353 | /* Similarly, update scaled mdev with regard to |m| */ |
| 354 | if (m < 0) { |
| 355 | m = -m; |
| 356 | m -= (hc->tx_mdev >> 2); |
| 357 | /* |
| 358 | * This neutralises RTO increase when RTT < SRTT - mdev |
| 359 | * (see P. Sarolahti, A. Kuznetsov,"Congestion Control |
| 360 | * in Linux TCP", USENIX 2002, pp. 49-62). |
| 361 | */ |
| 362 | if (m > 0) |
| 363 | m >>= 3; |
| 364 | } else { |
| 365 | m -= (hc->tx_mdev >> 2); |
| 366 | } |
| 367 | hc->tx_mdev += m; |
| 368 | |
| 369 | if (hc->tx_mdev > hc->tx_mdev_max) { |
| 370 | hc->tx_mdev_max = hc->tx_mdev; |
| 371 | if (hc->tx_mdev_max > hc->tx_rttvar) |
| 372 | hc->tx_rttvar = hc->tx_mdev_max; |
| 373 | } |
| 374 | |
| 375 | /* |
| 376 | * Decay RTTVAR at most once per flight, exploiting that |
| 377 | * 1) pipe <= cwnd <= Sequence_Window = W (RFC 4340, 7.5.2) |
| 378 | * 2) AWL = GSS-W+1 <= GAR <= GSS (RFC 4340, 7.5.1) |
| 379 | * GAR is a useful bound for FlightSize = pipe. |
| 380 | * AWL is probably too low here, as it over-estimates pipe. |
| 381 | */ |
| 382 | if (after48(dccp_sk(sk)->dccps_gar, hc->tx_rtt_seq)) { |
| 383 | if (hc->tx_mdev_max < hc->tx_rttvar) |
| 384 | hc->tx_rttvar -= (hc->tx_rttvar - |
| 385 | hc->tx_mdev_max) >> 2; |
| 386 | hc->tx_rtt_seq = dccp_sk(sk)->dccps_gss; |
Gerrit Renker | 4886fca | 2010-08-29 19:23:13 +0000 | [diff] [blame] | 387 | hc->tx_mdev_max = tcp_rto_min(sk); |
Gerrit Renker | 231cc2a | 2010-08-22 19:41:40 +0000 | [diff] [blame] | 388 | } |
| 389 | } |
| 390 | |
| 391 | /* |
| 392 | * Set RTO from SRTT and RTTVAR |
| 393 | * As in TCP, 4 * RTTVAR >= TCP_RTO_MIN, giving a minimum RTO of 200 ms. |
| 394 | * This agrees with RFC 4341, 5: |
| 395 | * "Because DCCP does not retransmit data, DCCP does not require |
| 396 | * TCP's recommended minimum timeout of one second". |
| 397 | */ |
| 398 | hc->tx_rto = (hc->tx_srtt >> 3) + hc->tx_rttvar; |
| 399 | |
| 400 | if (hc->tx_rto > DCCP_RTO_MAX) |
| 401 | hc->tx_rto = DCCP_RTO_MAX; |
| 402 | } |
| 403 | |
| 404 | static void ccid2_new_ack(struct sock *sk, struct ccid2_seq *seqp, |
| 405 | unsigned int *maxincr) |
Gerrit Renker | 410e27a | 2008-09-09 13:27:22 +0200 | [diff] [blame] | 406 | { |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 407 | struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk); |
Gerrit Renker | 410e27a | 2008-09-09 13:27:22 +0200 | [diff] [blame] | 408 | |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 409 | if (hc->tx_cwnd < hc->tx_ssthresh) { |
| 410 | if (*maxincr > 0 && ++hc->tx_packets_acked == 2) { |
| 411 | hc->tx_cwnd += 1; |
| 412 | *maxincr -= 1; |
| 413 | hc->tx_packets_acked = 0; |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 414 | } |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 415 | } else if (++hc->tx_packets_acked >= hc->tx_cwnd) { |
| 416 | hc->tx_cwnd += 1; |
| 417 | hc->tx_packets_acked = 0; |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 418 | } |
Gerrit Renker | 231cc2a | 2010-08-22 19:41:40 +0000 | [diff] [blame] | 419 | /* |
| 420 | * FIXME: RTT is sampled several times per acknowledgment (for each |
| 421 | * entry in the Ack Vector), instead of once per Ack (as in TCP SACK). |
| 422 | * This causes the RTT to be over-estimated, since the older entries |
| 423 | * in the Ack Vector have earlier sending times. |
| 424 | * The cleanest solution is to not use the ccid2s_sent field at all |
| 425 | * and instead use DCCP timestamps: requires changes in other places. |
| 426 | */ |
Gerrit Renker | d82b6f8 | 2010-08-29 19:23:10 +0000 | [diff] [blame] | 427 | ccid2_rtt_estimator(sk, ccid2_time_stamp - seqp->ccid2s_sent); |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 428 | } |
| 429 | |
Gerrit Renker | d50ad16 | 2007-11-24 21:40:24 -0200 | [diff] [blame] | 430 | static void ccid2_congestion_event(struct sock *sk, struct ccid2_seq *seqp) |
Andrea Bittau | 374bcf3 | 2006-09-19 13:14:43 -0700 | [diff] [blame] | 431 | { |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 432 | struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk); |
Gerrit Renker | d50ad16 | 2007-11-24 21:40:24 -0200 | [diff] [blame] | 433 | |
Gerrit Renker | d82b6f8 | 2010-08-29 19:23:10 +0000 | [diff] [blame] | 434 | if ((s32)(seqp->ccid2s_sent - hc->tx_last_cong) < 0) { |
Andrea Bittau | 374bcf3 | 2006-09-19 13:14:43 -0700 | [diff] [blame] | 435 | ccid2_pr_debug("Multiple losses in an RTT---treating as one\n"); |
| 436 | return; |
| 437 | } |
| 438 | |
Gerrit Renker | d82b6f8 | 2010-08-29 19:23:10 +0000 | [diff] [blame] | 439 | hc->tx_last_cong = ccid2_time_stamp; |
Andrea Bittau | 374bcf3 | 2006-09-19 13:14:43 -0700 | [diff] [blame] | 440 | |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 441 | hc->tx_cwnd = hc->tx_cwnd / 2 ? : 1U; |
| 442 | hc->tx_ssthresh = max(hc->tx_cwnd, 2U); |
Gerrit Renker | d50ad16 | 2007-11-24 21:40:24 -0200 | [diff] [blame] | 443 | |
| 444 | /* Avoid spurious timeouts resulting from Ack Ratio > cwnd */ |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 445 | if (dccp_sk(sk)->dccps_l_ack_ratio > hc->tx_cwnd) |
| 446 | ccid2_change_l_ack_ratio(sk, hc->tx_cwnd); |
Gerrit Renker | c8bf462 | 2008-09-04 07:30:19 +0200 | [diff] [blame] | 447 | } |
| 448 | |
Gerrit Renker | 7e87fe8 | 2010-11-14 17:26:13 +0100 | [diff] [blame] | 449 | static int ccid2_hc_tx_parse_options(struct sock *sk, u8 packet_type, |
| 450 | u8 option, u8 *optval, u8 optlen) |
| 451 | { |
| 452 | struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk); |
| 453 | |
| 454 | switch (option) { |
| 455 | case DCCPO_ACK_VECTOR_0: |
| 456 | case DCCPO_ACK_VECTOR_1: |
| 457 | return dccp_ackvec_parsed_add(&hc->tx_av_chunks, optval, optlen, |
| 458 | option - DCCPO_ACK_VECTOR_0); |
| 459 | } |
| 460 | return 0; |
| 461 | } |
| 462 | |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 463 | static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb) |
| 464 | { |
| 465 | struct dccp_sock *dp = dccp_sk(sk); |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 466 | struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk); |
Gerrit Renker | 1c0e0a0 | 2010-10-27 19:16:28 +0000 | [diff] [blame] | 467 | const bool sender_was_blocked = ccid2_cwnd_network_limited(hc); |
Gerrit Renker | 7e87fe8 | 2010-11-14 17:26:13 +0100 | [diff] [blame] | 468 | struct dccp_ackvec_parsed *avp; |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 469 | u64 ackno, seqno; |
| 470 | struct ccid2_seq *seqp; |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 471 | int done = 0; |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 472 | unsigned int maxincr = 0; |
| 473 | |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 474 | /* check reverse path congestion */ |
| 475 | seqno = DCCP_SKB_CB(skb)->dccpd_seq; |
| 476 | |
| 477 | /* XXX this whole "algorithm" is broken. Need to fix it to keep track |
| 478 | * of the seqnos of the dupacks so that rpseq and rpdupack are correct |
| 479 | * -sorbo. |
| 480 | */ |
| 481 | /* need to bootstrap */ |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 482 | if (hc->tx_rpdupack == -1) { |
| 483 | hc->tx_rpdupack = 0; |
| 484 | hc->tx_rpseq = seqno; |
Arnaldo Carvalho de Melo | c0c736d | 2006-03-20 22:05:37 -0800 | [diff] [blame] | 485 | } else { |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 486 | /* check if packet is consecutive */ |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 487 | if (dccp_delta_seqno(hc->tx_rpseq, seqno) == 1) |
| 488 | hc->tx_rpseq = seqno; |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 489 | /* it's a later packet */ |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 490 | else if (after48(seqno, hc->tx_rpseq)) { |
| 491 | hc->tx_rpdupack++; |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 492 | |
| 493 | /* check if we got enough dupacks */ |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 494 | if (hc->tx_rpdupack >= NUMDUPACK) { |
| 495 | hc->tx_rpdupack = -1; /* XXX lame */ |
| 496 | hc->tx_rpseq = 0; |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 497 | |
Gerrit Renker | df054e1 | 2007-11-24 21:32:53 -0200 | [diff] [blame] | 498 | ccid2_change_l_ack_ratio(sk, 2 * dp->dccps_l_ack_ratio); |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 499 | } |
| 500 | } |
| 501 | } |
| 502 | |
| 503 | /* check forward path congestion */ |
Gerrit Renker | 7e87fe8 | 2010-11-14 17:26:13 +0100 | [diff] [blame] | 504 | if (dccp_packet_without_ack(skb)) |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 505 | return; |
| 506 | |
Gerrit Renker | 7e87fe8 | 2010-11-14 17:26:13 +0100 | [diff] [blame] | 507 | /* still didn't send out new data packets */ |
| 508 | if (hc->tx_seqh == hc->tx_seqt) |
| 509 | goto done; |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 510 | |
| 511 | ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq; |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 512 | if (after48(ackno, hc->tx_high_ack)) |
| 513 | hc->tx_high_ack = ackno; |
Andrea Bittau | 32aac18 | 2006-11-16 14:28:40 -0200 | [diff] [blame] | 514 | |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 515 | seqp = hc->tx_seqt; |
Andrea Bittau | 32aac18 | 2006-11-16 14:28:40 -0200 | [diff] [blame] | 516 | while (before48(seqp->ccid2s_seq, ackno)) { |
| 517 | seqp = seqp->ccid2s_next; |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 518 | if (seqp == hc->tx_seqh) { |
| 519 | seqp = hc->tx_seqh->ccid2s_prev; |
Andrea Bittau | 32aac18 | 2006-11-16 14:28:40 -0200 | [diff] [blame] | 520 | break; |
| 521 | } |
| 522 | } |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 523 | |
Gerrit Renker | a302002 | 2007-11-24 22:10:29 -0200 | [diff] [blame] | 524 | /* |
| 525 | * In slow-start, cwnd can increase up to a maximum of Ack Ratio/2 |
| 526 | * packets per acknowledgement. Rounding up avoids that cwnd is not |
| 527 | * advanced when Ack Ratio is 1 and gives a slight edge otherwise. |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 528 | */ |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 529 | if (hc->tx_cwnd < hc->tx_ssthresh) |
Gerrit Renker | a302002 | 2007-11-24 22:10:29 -0200 | [diff] [blame] | 530 | maxincr = DIV_ROUND_UP(dp->dccps_l_ack_ratio, 2); |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 531 | |
| 532 | /* go through all ack vectors */ |
Gerrit Renker | 7e87fe8 | 2010-11-14 17:26:13 +0100 | [diff] [blame] | 533 | list_for_each_entry(avp, &hc->tx_av_chunks, node) { |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 534 | /* go through this ack vector */ |
Gerrit Renker | 7e87fe8 | 2010-11-14 17:26:13 +0100 | [diff] [blame] | 535 | for (; avp->len--; avp->vec++) { |
| 536 | u64 ackno_end_rl = SUB48(ackno, |
| 537 | dccp_ackvec_runlen(avp->vec)); |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 538 | |
Gerrit Renker | 7e87fe8 | 2010-11-14 17:26:13 +0100 | [diff] [blame] | 539 | ccid2_pr_debug("ackvec %llu |%u,%u|\n", |
Randy Dunlap | 234af48 | 2006-10-29 16:03:30 -0800 | [diff] [blame] | 540 | (unsigned long long)ackno, |
Gerrit Renker | 7e87fe8 | 2010-11-14 17:26:13 +0100 | [diff] [blame] | 541 | dccp_ackvec_state(avp->vec) >> 6, |
| 542 | dccp_ackvec_runlen(avp->vec)); |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 543 | /* if the seqno we are analyzing is larger than the |
| 544 | * current ackno, then move towards the tail of our |
| 545 | * seqnos. |
| 546 | */ |
| 547 | while (after48(seqp->ccid2s_seq, ackno)) { |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 548 | if (seqp == hc->tx_seqt) { |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 549 | done = 1; |
| 550 | break; |
| 551 | } |
| 552 | seqp = seqp->ccid2s_prev; |
| 553 | } |
| 554 | if (done) |
| 555 | break; |
| 556 | |
| 557 | /* check all seqnos in the range of the vector |
| 558 | * run length |
| 559 | */ |
| 560 | while (between48(seqp->ccid2s_seq,ackno_end_rl,ackno)) { |
Gerrit Renker | 7e87fe8 | 2010-11-14 17:26:13 +0100 | [diff] [blame] | 561 | const u8 state = dccp_ackvec_state(avp->vec); |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 562 | |
| 563 | /* new packet received or marked */ |
Gerrit Renker | f17a37c | 2010-11-10 21:20:07 +0100 | [diff] [blame] | 564 | if (state != DCCPAV_NOT_RECEIVED && |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 565 | !seqp->ccid2s_acked) { |
Gerrit Renker | f17a37c | 2010-11-10 21:20:07 +0100 | [diff] [blame] | 566 | if (state == DCCPAV_ECN_MARKED) |
Gerrit Renker | d50ad16 | 2007-11-24 21:40:24 -0200 | [diff] [blame] | 567 | ccid2_congestion_event(sk, |
Andrea Bittau | 374bcf3 | 2006-09-19 13:14:43 -0700 | [diff] [blame] | 568 | seqp); |
Gerrit Renker | f17a37c | 2010-11-10 21:20:07 +0100 | [diff] [blame] | 569 | else |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 570 | ccid2_new_ack(sk, seqp, |
| 571 | &maxincr); |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 572 | |
| 573 | seqp->ccid2s_acked = 1; |
| 574 | ccid2_pr_debug("Got ack for %llu\n", |
Randy Dunlap | 234af48 | 2006-10-29 16:03:30 -0800 | [diff] [blame] | 575 | (unsigned long long)seqp->ccid2s_seq); |
Gerrit Renker | c38c92a | 2010-08-22 19:41:39 +0000 | [diff] [blame] | 576 | hc->tx_pipe--; |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 577 | } |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 578 | if (seqp == hc->tx_seqt) { |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 579 | done = 1; |
| 580 | break; |
| 581 | } |
Gerrit Renker | 3de5489 | 2007-11-24 20:37:48 -0200 | [diff] [blame] | 582 | seqp = seqp->ccid2s_prev; |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 583 | } |
| 584 | if (done) |
| 585 | break; |
| 586 | |
Gerrit Renker | cfbbeab | 2007-11-24 20:43:59 -0200 | [diff] [blame] | 587 | ackno = SUB48(ackno_end_rl, 1); |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 588 | } |
| 589 | if (done) |
| 590 | break; |
| 591 | } |
| 592 | |
| 593 | /* The state about what is acked should be correct now |
| 594 | * Check for NUMDUPACK |
| 595 | */ |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 596 | seqp = hc->tx_seqt; |
| 597 | while (before48(seqp->ccid2s_seq, hc->tx_high_ack)) { |
Andrea Bittau | 32aac18 | 2006-11-16 14:28:40 -0200 | [diff] [blame] | 598 | seqp = seqp->ccid2s_next; |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 599 | if (seqp == hc->tx_seqh) { |
| 600 | seqp = hc->tx_seqh->ccid2s_prev; |
Andrea Bittau | 32aac18 | 2006-11-16 14:28:40 -0200 | [diff] [blame] | 601 | break; |
| 602 | } |
| 603 | } |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 604 | done = 0; |
| 605 | while (1) { |
| 606 | if (seqp->ccid2s_acked) { |
| 607 | done++; |
Gerrit Renker | 63df18a | 2007-11-24 22:04:35 -0200 | [diff] [blame] | 608 | if (done == NUMDUPACK) |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 609 | break; |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 610 | } |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 611 | if (seqp == hc->tx_seqt) |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 612 | break; |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 613 | seqp = seqp->ccid2s_prev; |
| 614 | } |
| 615 | |
| 616 | /* If there are at least 3 acknowledgements, anything unacknowledged |
| 617 | * below the last sequence number is considered lost |
| 618 | */ |
Gerrit Renker | 63df18a | 2007-11-24 22:04:35 -0200 | [diff] [blame] | 619 | if (done == NUMDUPACK) { |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 620 | struct ccid2_seq *last_acked = seqp; |
| 621 | |
| 622 | /* check for lost packets */ |
| 623 | while (1) { |
| 624 | if (!seqp->ccid2s_acked) { |
Andrea Bittau | 374bcf3 | 2006-09-19 13:14:43 -0700 | [diff] [blame] | 625 | ccid2_pr_debug("Packet lost: %llu\n", |
Randy Dunlap | 234af48 | 2006-10-29 16:03:30 -0800 | [diff] [blame] | 626 | (unsigned long long)seqp->ccid2s_seq); |
Andrea Bittau | 374bcf3 | 2006-09-19 13:14:43 -0700 | [diff] [blame] | 627 | /* XXX need to traverse from tail -> head in |
| 628 | * order to detect multiple congestion events in |
| 629 | * one ack vector. |
| 630 | */ |
Gerrit Renker | d50ad16 | 2007-11-24 21:40:24 -0200 | [diff] [blame] | 631 | ccid2_congestion_event(sk, seqp); |
Gerrit Renker | c38c92a | 2010-08-22 19:41:39 +0000 | [diff] [blame] | 632 | hc->tx_pipe--; |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 633 | } |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 634 | if (seqp == hc->tx_seqt) |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 635 | break; |
| 636 | seqp = seqp->ccid2s_prev; |
| 637 | } |
| 638 | |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 639 | hc->tx_seqt = last_acked; |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 640 | } |
| 641 | |
| 642 | /* trim acked packets in tail */ |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 643 | while (hc->tx_seqt != hc->tx_seqh) { |
| 644 | if (!hc->tx_seqt->ccid2s_acked) |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 645 | break; |
| 646 | |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 647 | hc->tx_seqt = hc->tx_seqt->ccid2s_next; |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 648 | } |
Gerrit Renker | c38c92a | 2010-08-22 19:41:39 +0000 | [diff] [blame] | 649 | |
| 650 | /* restart RTO timer if not all outstanding data has been acked */ |
| 651 | if (hc->tx_pipe == 0) |
| 652 | sk_stop_timer(sk, &hc->tx_rtotimer); |
| 653 | else |
| 654 | sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + hc->tx_rto); |
Gerrit Renker | 7e87fe8 | 2010-11-14 17:26:13 +0100 | [diff] [blame] | 655 | done: |
Gerrit Renker | 1c0e0a0 | 2010-10-27 19:16:28 +0000 | [diff] [blame] | 656 | /* check if incoming Acks allow pending packets to be sent */ |
| 657 | if (sender_was_blocked && !ccid2_cwnd_network_limited(hc)) |
| 658 | tasklet_schedule(&dccp_sk(sk)->dccps_xmitlet); |
Gerrit Renker | 7e87fe8 | 2010-11-14 17:26:13 +0100 | [diff] [blame] | 659 | dccp_ackvec_parsed_cleanup(&hc->tx_av_chunks); |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 660 | } |
| 661 | |
Arnaldo Carvalho de Melo | 91f0ebf | 2006-03-20 19:21:44 -0800 | [diff] [blame] | 662 | static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk) |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 663 | { |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 664 | struct ccid2_hc_tx_sock *hc = ccid_priv(ccid); |
Gerrit Renker | b00d2bb | 2007-11-24 21:44:30 -0200 | [diff] [blame] | 665 | struct dccp_sock *dp = dccp_sk(sk); |
| 666 | u32 max_ratio; |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 667 | |
Gerrit Renker | b00d2bb | 2007-11-24 21:44:30 -0200 | [diff] [blame] | 668 | /* RFC 4341, 5: initialise ssthresh to arbitrarily high (max) value */ |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 669 | hc->tx_ssthresh = ~0U; |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 670 | |
Gerrit Renker | 22b71c8 | 2010-08-29 19:23:12 +0000 | [diff] [blame] | 671 | /* Use larger initial windows (RFC 4341, section 5). */ |
| 672 | hc->tx_cwnd = rfc3390_bytes_to_packets(dp->dccps_mss_cache); |
Gerrit Renker | 113ced1 | 2011-07-03 09:55:03 -0600 | [diff] [blame] | 673 | hc->tx_expected_wnd = hc->tx_cwnd; |
Gerrit Renker | b00d2bb | 2007-11-24 21:44:30 -0200 | [diff] [blame] | 674 | |
| 675 | /* Make sure that Ack Ratio is enabled and within bounds. */ |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 676 | max_ratio = DIV_ROUND_UP(hc->tx_cwnd, 2); |
Gerrit Renker | b00d2bb | 2007-11-24 21:44:30 -0200 | [diff] [blame] | 677 | if (dp->dccps_l_ack_ratio == 0 || dp->dccps_l_ack_ratio > max_ratio) |
| 678 | dp->dccps_l_ack_ratio = max_ratio; |
| 679 | |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 680 | /* XXX init ~ to window size... */ |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 681 | if (ccid2_hc_tx_alloc_seq(hc)) |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 682 | return -ENOMEM; |
Arnaldo Carvalho de Melo | 91f0ebf | 2006-03-20 19:21:44 -0800 | [diff] [blame] | 683 | |
Gerrit Renker | 231cc2a | 2010-08-22 19:41:40 +0000 | [diff] [blame] | 684 | hc->tx_rto = DCCP_TIMEOUT_INIT; |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 685 | hc->tx_rpdupack = -1; |
Gerrit Renker | 113ced1 | 2011-07-03 09:55:03 -0600 | [diff] [blame] | 686 | hc->tx_last_cong = hc->tx_lsndtime = hc->tx_cwnd_stamp = ccid2_time_stamp; |
| 687 | hc->tx_cwnd_used = 0; |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 688 | setup_timer(&hc->tx_rtotimer, ccid2_hc_tx_rto_expire, |
Gerrit Renker | 410e27a | 2008-09-09 13:27:22 +0200 | [diff] [blame] | 689 | (unsigned long)sk); |
Gerrit Renker | 7e87fe8 | 2010-11-14 17:26:13 +0100 | [diff] [blame] | 690 | INIT_LIST_HEAD(&hc->tx_av_chunks); |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 691 | return 0; |
| 692 | } |
| 693 | |
| 694 | static void ccid2_hc_tx_exit(struct sock *sk) |
| 695 | { |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 696 | struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk); |
Andrea Bittau | 07978aa | 2006-09-19 13:13:37 -0700 | [diff] [blame] | 697 | int i; |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 698 | |
Gerrit Renker | d26eeb0 | 2010-08-29 19:23:11 +0000 | [diff] [blame] | 699 | sk_stop_timer(sk, &hc->tx_rtotimer); |
Andrea Bittau | 07978aa | 2006-09-19 13:13:37 -0700 | [diff] [blame] | 700 | |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 701 | for (i = 0; i < hc->tx_seqbufc; i++) |
| 702 | kfree(hc->tx_seqbuf[i]); |
| 703 | hc->tx_seqbufc = 0; |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 704 | } |
| 705 | |
| 706 | static void ccid2_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb) |
| 707 | { |
Gerrit Renker | 77d2dd9 | 2009-10-05 00:53:12 +0000 | [diff] [blame] | 708 | struct ccid2_hc_rx_sock *hc = ccid2_hc_rx_sk(sk); |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 709 | |
Gerrit Renker | 58fdea0 | 2011-07-03 09:53:12 -0600 | [diff] [blame] | 710 | if (!dccp_data_packet(skb)) |
| 711 | return; |
| 712 | |
| 713 | if (++hc->rx_num_data_pkts >= dccp_sk(sk)->dccps_r_ack_ratio) { |
| 714 | dccp_send_ack(sk); |
| 715 | hc->rx_num_data_pkts = 0; |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 716 | } |
| 717 | } |
| 718 | |
Gerrit Renker | ddebc97 | 2009-01-04 21:42:53 -0800 | [diff] [blame] | 719 | struct ccid_operations ccid2_ops = { |
Gerrit Renker | 7e87fe8 | 2010-11-14 17:26:13 +0100 | [diff] [blame] | 720 | .ccid_id = DCCPC_CCID2, |
| 721 | .ccid_name = "TCP-like", |
| 722 | .ccid_hc_tx_obj_size = sizeof(struct ccid2_hc_tx_sock), |
| 723 | .ccid_hc_tx_init = ccid2_hc_tx_init, |
| 724 | .ccid_hc_tx_exit = ccid2_hc_tx_exit, |
| 725 | .ccid_hc_tx_send_packet = ccid2_hc_tx_send_packet, |
| 726 | .ccid_hc_tx_packet_sent = ccid2_hc_tx_packet_sent, |
| 727 | .ccid_hc_tx_parse_options = ccid2_hc_tx_parse_options, |
| 728 | .ccid_hc_tx_packet_recv = ccid2_hc_tx_packet_recv, |
| 729 | .ccid_hc_rx_obj_size = sizeof(struct ccid2_hc_rx_sock), |
| 730 | .ccid_hc_rx_packet_recv = ccid2_hc_rx_packet_recv, |
Andrea Bittau | 2a91aa3 | 2006-03-20 17:41:47 -0800 | [diff] [blame] | 731 | }; |
| 732 | |
Gerrit Renker | 8411671 | 2006-11-20 18:26:03 -0200 | [diff] [blame] | 733 | #ifdef CONFIG_IP_DCCP_CCID2_DEBUG |
Gerrit Renker | 4326499 | 2008-08-23 13:28:27 +0200 | [diff] [blame] | 734 | module_param(ccid2_debug, bool, 0644); |
Gerrit Renker | ddebc97 | 2009-01-04 21:42:53 -0800 | [diff] [blame] | 735 | MODULE_PARM_DESC(ccid2_debug, "Enable CCID-2 debug messages"); |
Gerrit Renker | 8411671 | 2006-11-20 18:26:03 -0200 | [diff] [blame] | 736 | #endif |