Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 1 | /* |
| 2 | * net/dccp/ackvec.c |
| 3 | * |
Gerrit Renker | f17a37c | 2010-11-10 21:20:07 +0100 | [diff] [blame] | 4 | * An implementation of Ack Vectors for the DCCP protocol |
| 5 | * Copyright (c) 2007 University of Aberdeen, Scotland, UK |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 6 | * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@ghostprotocols.net> |
| 7 | * |
| 8 | * This program is free software; you can redistribute it and/or modify it |
| 9 | * under the terms of the GNU General Public License as published by the |
| 10 | * Free Software Foundation; version 2 of the License; |
| 11 | */ |
| 12 | |
| 13 | #include "ackvec.h" |
| 14 | #include "dccp.h" |
| 15 | |
Arnaldo Carvalho de Melo | 9b07ef5 | 2006-03-20 17:16:17 -0800 | [diff] [blame] | 16 | #include <linux/init.h> |
| 17 | #include <linux/errno.h> |
| 18 | #include <linux/kernel.h> |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 19 | #include <linux/skbuff.h> |
Arnaldo Carvalho de Melo | 9b07ef5 | 2006-03-20 17:16:17 -0800 | [diff] [blame] | 20 | #include <linux/slab.h> |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 21 | |
| 22 | #include <net/sock.h> |
| 23 | |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 24 | static struct kmem_cache *dccp_ackvec_slab; |
| 25 | static struct kmem_cache *dccp_ackvec_record_slab; |
Andrea Bittau | 02bcf28 | 2006-03-20 17:19:55 -0800 | [diff] [blame] | 26 | |
Gerrit Renker | f17a37c | 2010-11-10 21:20:07 +0100 | [diff] [blame] | 27 | struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority) |
Andrea Bittau | 02bcf28 | 2006-03-20 17:19:55 -0800 | [diff] [blame] | 28 | { |
Gerrit Renker | f17a37c | 2010-11-10 21:20:07 +0100 | [diff] [blame] | 29 | struct dccp_ackvec *av = kmem_cache_zalloc(dccp_ackvec_slab, priority); |
Andrea Bittau | 02bcf28 | 2006-03-20 17:19:55 -0800 | [diff] [blame] | 30 | |
Gerrit Renker | f17a37c | 2010-11-10 21:20:07 +0100 | [diff] [blame] | 31 | if (av != NULL) { |
Gerrit Renker | b3d14bf | 2010-11-10 21:21:35 +0100 | [diff] [blame] | 32 | av->av_buf_head = av->av_buf_tail = DCCPAV_MAX_ACKVEC_LEN - 1; |
Gerrit Renker | f17a37c | 2010-11-10 21:20:07 +0100 | [diff] [blame] | 33 | INIT_LIST_HEAD(&av->av_records); |
| 34 | } |
| 35 | return av; |
Andrea Bittau | 02bcf28 | 2006-03-20 17:19:55 -0800 | [diff] [blame] | 36 | } |
| 37 | |
Gerrit Renker | f17a37c | 2010-11-10 21:20:07 +0100 | [diff] [blame] | 38 | static void dccp_ackvec_purge_records(struct dccp_ackvec *av) |
Andrea Bittau | 02bcf28 | 2006-03-20 17:19:55 -0800 | [diff] [blame] | 39 | { |
Gerrit Renker | f17a37c | 2010-11-10 21:20:07 +0100 | [diff] [blame] | 40 | struct dccp_ackvec_record *cur, *next; |
| 41 | |
| 42 | list_for_each_entry_safe(cur, next, &av->av_records, avr_node) |
| 43 | kmem_cache_free(dccp_ackvec_record_slab, cur); |
| 44 | INIT_LIST_HEAD(&av->av_records); |
| 45 | } |
| 46 | |
| 47 | void dccp_ackvec_free(struct dccp_ackvec *av) |
| 48 | { |
| 49 | if (likely(av != NULL)) { |
| 50 | dccp_ackvec_purge_records(av); |
| 51 | kmem_cache_free(dccp_ackvec_slab, av); |
| 52 | } |
Andrea Bittau | 02bcf28 | 2006-03-20 17:19:55 -0800 | [diff] [blame] | 53 | } |
| 54 | |
Gerrit Renker | 7d87093 | 2010-11-10 21:21:02 +0100 | [diff] [blame] | 55 | /** |
| 56 | * dccp_ackvec_update_records - Record information about sent Ack Vectors |
| 57 | * @av: Ack Vector records to update |
| 58 | * @seqno: Sequence number of the packet carrying the Ack Vector just sent |
| 59 | * @nonce_sum: The sum of all buffer nonces contained in the Ack Vector |
| 60 | */ |
| 61 | int dccp_ackvec_update_records(struct dccp_ackvec *av, u64 seqno, u8 nonce_sum) |
Andrea Bittau | 02bcf28 | 2006-03-20 17:19:55 -0800 | [diff] [blame] | 62 | { |
Andrea Bittau | 02bcf28 | 2006-03-20 17:19:55 -0800 | [diff] [blame] | 63 | struct dccp_ackvec_record *avr; |
| 64 | |
Gerrit Renker | f17a37c | 2010-11-10 21:20:07 +0100 | [diff] [blame] | 65 | avr = kmem_cache_alloc(dccp_ackvec_record_slab, GFP_ATOMIC); |
Arnaldo Carvalho de Melo | 2d0817d | 2006-03-20 22:32:06 -0800 | [diff] [blame] | 66 | if (avr == NULL) |
Gerrit Renker | 7d87093 | 2010-11-10 21:21:02 +0100 | [diff] [blame] | 67 | return -ENOBUFS; |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 68 | |
Gerrit Renker | 7d87093 | 2010-11-10 21:21:02 +0100 | [diff] [blame] | 69 | avr->avr_ack_seqno = seqno; |
Gerrit Renker | f17a37c | 2010-11-10 21:20:07 +0100 | [diff] [blame] | 70 | avr->avr_ack_ptr = av->av_buf_head; |
| 71 | avr->avr_ack_ackno = av->av_buf_ackno; |
Gerrit Renker | 7d87093 | 2010-11-10 21:21:02 +0100 | [diff] [blame] | 72 | avr->avr_ack_nonce = nonce_sum; |
Gerrit Renker | f17a37c | 2010-11-10 21:20:07 +0100 | [diff] [blame] | 73 | avr->avr_ack_runlen = dccp_ackvec_runlen(av->av_buf + av->av_buf_head); |
Gerrit Renker | 7d87093 | 2010-11-10 21:21:02 +0100 | [diff] [blame] | 74 | /* |
Gerrit Renker | b3d14bf | 2010-11-10 21:21:35 +0100 | [diff] [blame] | 75 | * When the buffer overflows, we keep no more than one record. This is |
| 76 | * the simplest way of disambiguating sender-Acks dating from before the |
| 77 | * overflow from sender-Acks which refer to after the overflow; a simple |
| 78 | * solution is preferable here since we are handling an exception. |
| 79 | */ |
| 80 | if (av->av_overflow) |
| 81 | dccp_ackvec_purge_records(av); |
| 82 | /* |
Gerrit Renker | 7d87093 | 2010-11-10 21:21:02 +0100 | [diff] [blame] | 83 | * Since GSS is incremented for each packet, the list is automatically |
| 84 | * arranged in descending order of @ack_seqno. |
| 85 | */ |
| 86 | list_add(&avr->avr_node, &av->av_records); |
Andrea Bittau | 02bcf28 | 2006-03-20 17:19:55 -0800 | [diff] [blame] | 87 | |
Gerrit Renker | 7d87093 | 2010-11-10 21:21:02 +0100 | [diff] [blame] | 88 | dccp_pr_debug("Added Vector, ack_seqno=%llu, ack_ackno=%llu (rl=%u)\n", |
Gerrit Renker | a47c510 | 2007-12-30 04:19:31 -0800 | [diff] [blame] | 89 | (unsigned long long)avr->avr_ack_seqno, |
Gerrit Renker | 7d87093 | 2010-11-10 21:21:02 +0100 | [diff] [blame] | 90 | (unsigned long long)avr->avr_ack_ackno, |
| 91 | avr->avr_ack_runlen); |
Andrea Bittau | 02bcf28 | 2006-03-20 17:19:55 -0800 | [diff] [blame] | 92 | return 0; |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 93 | } |
| 94 | |
Gerrit Renker | 5753fdf | 2010-11-14 17:25:11 +0100 | [diff] [blame^] | 95 | static struct dccp_ackvec_record *dccp_ackvec_lookup(struct list_head *av_list, |
| 96 | const u64 ackno) |
| 97 | { |
| 98 | struct dccp_ackvec_record *avr; |
| 99 | /* |
| 100 | * Exploit that records are inserted in descending order of sequence |
| 101 | * number, start with the oldest record first. If @ackno is `before' |
| 102 | * the earliest ack_ackno, the packet is too old to be considered. |
| 103 | */ |
| 104 | list_for_each_entry_reverse(avr, av_list, avr_node) { |
| 105 | if (avr->avr_ack_seqno == ackno) |
| 106 | return avr; |
| 107 | if (before48(ackno, avr->avr_ack_seqno)) |
| 108 | break; |
| 109 | } |
| 110 | return NULL; |
| 111 | } |
| 112 | |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 113 | /* |
Gerrit Renker | b3d14bf | 2010-11-10 21:21:35 +0100 | [diff] [blame] | 114 | * Buffer index and length computation using modulo-buffersize arithmetic. |
| 115 | * Note that, as pointers move from right to left, head is `before' tail. |
| 116 | */ |
| 117 | static inline u16 __ackvec_idx_add(const u16 a, const u16 b) |
| 118 | { |
| 119 | return (a + b) % DCCPAV_MAX_ACKVEC_LEN; |
| 120 | } |
| 121 | |
| 122 | static inline u16 __ackvec_idx_sub(const u16 a, const u16 b) |
| 123 | { |
| 124 | return __ackvec_idx_add(a, DCCPAV_MAX_ACKVEC_LEN - b); |
| 125 | } |
| 126 | |
| 127 | u16 dccp_ackvec_buflen(const struct dccp_ackvec *av) |
| 128 | { |
| 129 | if (unlikely(av->av_overflow)) |
| 130 | return DCCPAV_MAX_ACKVEC_LEN; |
| 131 | return __ackvec_idx_sub(av->av_buf_tail, av->av_buf_head); |
| 132 | } |
| 133 | |
| 134 | /* |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 135 | * If several packets are missing, the HC-Receiver may prefer to enter multiple |
| 136 | * bytes with run length 0, rather than a single byte with a larger run length; |
| 137 | * this simplifies table updates if one of the missing packets arrives. |
| 138 | */ |
| 139 | static inline int dccp_ackvec_set_buf_head_state(struct dccp_ackvec *av, |
| 140 | const unsigned int packets, |
Arnaldo Carvalho de Melo | e4dfd44 | 2006-01-04 01:46:34 -0200 | [diff] [blame] | 141 | const unsigned char state) |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 142 | { |
Kulikov Vasiliy | 8e64159 | 2010-07-17 05:21:00 +0000 | [diff] [blame] | 143 | long gap; |
Kris Katterjohn | a8fc3d8 | 2006-01-17 13:03:54 -0800 | [diff] [blame] | 144 | long new_head; |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 145 | |
Gerrit Renker | f17a37c | 2010-11-10 21:20:07 +0100 | [diff] [blame] | 146 | if (av->av_vec_len + packets > DCCPAV_MAX_ACKVEC_LEN) |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 147 | return -ENOBUFS; |
| 148 | |
| 149 | gap = packets - 1; |
Gerrit Renker | a47c510 | 2007-12-30 04:19:31 -0800 | [diff] [blame] | 150 | new_head = av->av_buf_head - packets; |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 151 | |
| 152 | if (new_head < 0) { |
| 153 | if (gap > 0) { |
Gerrit Renker | f17a37c | 2010-11-10 21:20:07 +0100 | [diff] [blame] | 154 | memset(av->av_buf, DCCPAV_NOT_RECEIVED, |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 155 | gap + new_head + 1); |
| 156 | gap = -new_head; |
| 157 | } |
Gerrit Renker | f17a37c | 2010-11-10 21:20:07 +0100 | [diff] [blame] | 158 | new_head += DCCPAV_MAX_ACKVEC_LEN; |
Arnaldo Carvalho de Melo | 8109b02 | 2006-12-10 16:01:18 -0200 | [diff] [blame] | 159 | } |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 160 | |
Gerrit Renker | a47c510 | 2007-12-30 04:19:31 -0800 | [diff] [blame] | 161 | av->av_buf_head = new_head; |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 162 | |
| 163 | if (gap > 0) |
Gerrit Renker | a47c510 | 2007-12-30 04:19:31 -0800 | [diff] [blame] | 164 | memset(av->av_buf + av->av_buf_head + 1, |
Gerrit Renker | f17a37c | 2010-11-10 21:20:07 +0100 | [diff] [blame] | 165 | DCCPAV_NOT_RECEIVED, gap); |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 166 | |
Gerrit Renker | a47c510 | 2007-12-30 04:19:31 -0800 | [diff] [blame] | 167 | av->av_buf[av->av_buf_head] = state; |
| 168 | av->av_vec_len += packets; |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 169 | return 0; |
| 170 | } |
| 171 | |
| 172 | /* |
Gerrit Renker | 0e64e94 | 2006-10-24 16:17:51 -0700 | [diff] [blame] | 173 | * Implements the RFC 4340, Appendix A |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 174 | */ |
| 175 | int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk, |
| 176 | const u64 ackno, const u8 state) |
| 177 | { |
Gerrit Renker | f17a37c | 2010-11-10 21:20:07 +0100 | [diff] [blame] | 178 | u8 *cur_head = av->av_buf + av->av_buf_head, |
| 179 | *buf_end = av->av_buf + DCCPAV_MAX_ACKVEC_LEN; |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 180 | /* |
| 181 | * Check at the right places if the buffer is full, if it is, tell the |
| 182 | * caller to start dropping packets till the HC-Sender acks our ACK |
Gerrit Renker | a47c510 | 2007-12-30 04:19:31 -0800 | [diff] [blame] | 183 | * vectors, when we will free up space in av_buf. |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 184 | * |
| 185 | * We may well decide to do buffer compression, etc, but for now lets |
| 186 | * just drop. |
| 187 | * |
Gerrit Renker | 0e64e94 | 2006-10-24 16:17:51 -0700 | [diff] [blame] | 188 | * From Appendix A.1.1 (`New Packets'): |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 189 | * |
| 190 | * Of course, the circular buffer may overflow, either when the |
| 191 | * HC-Sender is sending data at a very high rate, when the |
| 192 | * HC-Receiver's acknowledgements are not reaching the HC-Sender, |
| 193 | * or when the HC-Sender is forgetting to acknowledge those acks |
| 194 | * (so the HC-Receiver is unable to clean up old state). In this |
| 195 | * case, the HC-Receiver should either compress the buffer (by |
| 196 | * increasing run lengths when possible), transfer its state to |
| 197 | * a larger buffer, or, as a last resort, drop all received |
| 198 | * packets, without processing them whatsoever, until its buffer |
| 199 | * shrinks again. |
| 200 | */ |
| 201 | |
| 202 | /* See if this is the first ackno being inserted */ |
Gerrit Renker | a47c510 | 2007-12-30 04:19:31 -0800 | [diff] [blame] | 203 | if (av->av_vec_len == 0) { |
Gerrit Renker | f17a37c | 2010-11-10 21:20:07 +0100 | [diff] [blame] | 204 | *cur_head = state; |
Gerrit Renker | a47c510 | 2007-12-30 04:19:31 -0800 | [diff] [blame] | 205 | av->av_vec_len = 1; |
| 206 | } else if (after48(ackno, av->av_buf_ackno)) { |
| 207 | const u64 delta = dccp_delta_seqno(av->av_buf_ackno, ackno); |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 208 | |
| 209 | /* |
| 210 | * Look if the state of this packet is the same as the |
| 211 | * previous ackno and if so if we can bump the head len. |
| 212 | */ |
Gerrit Renker | f17a37c | 2010-11-10 21:20:07 +0100 | [diff] [blame] | 213 | if (delta == 1 && dccp_ackvec_state(cur_head) == state && |
| 214 | dccp_ackvec_runlen(cur_head) < DCCPAV_MAX_RUNLEN) |
| 215 | *cur_head += 1; |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 216 | else if (dccp_ackvec_set_buf_head_state(av, delta, state)) |
| 217 | return -ENOBUFS; |
| 218 | } else { |
| 219 | /* |
| 220 | * A.1.2. Old Packets |
| 221 | * |
Gerrit Renker | 0e64e94 | 2006-10-24 16:17:51 -0700 | [diff] [blame] | 222 | * When a packet with Sequence Number S <= buf_ackno |
| 223 | * arrives, the HC-Receiver will scan the table for |
| 224 | * the byte corresponding to S. (Indexing structures |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 225 | * could reduce the complexity of this scan.) |
| 226 | */ |
Gerrit Renker | a47c510 | 2007-12-30 04:19:31 -0800 | [diff] [blame] | 227 | u64 delta = dccp_delta_seqno(ackno, av->av_buf_ackno); |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 228 | |
| 229 | while (1) { |
Gerrit Renker | f17a37c | 2010-11-10 21:20:07 +0100 | [diff] [blame] | 230 | const u8 len = dccp_ackvec_runlen(cur_head); |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 231 | /* |
Gerrit Renker | a47c510 | 2007-12-30 04:19:31 -0800 | [diff] [blame] | 232 | * valid packets not yet in av_buf have a reserved |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 233 | * entry, with a len equal to 0. |
| 234 | */ |
Gerrit Renker | f17a37c | 2010-11-10 21:20:07 +0100 | [diff] [blame] | 235 | if (*cur_head == DCCPAV_NOT_RECEIVED && delta == 0) { |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 236 | dccp_pr_debug("Found %llu reserved seat!\n", |
| 237 | (unsigned long long)ackno); |
Gerrit Renker | f17a37c | 2010-11-10 21:20:07 +0100 | [diff] [blame] | 238 | *cur_head = state; |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 239 | goto out; |
| 240 | } |
| 241 | /* len == 0 means one packet */ |
| 242 | if (delta < len + 1) |
| 243 | goto out_duplicate; |
| 244 | |
| 245 | delta -= len + 1; |
Gerrit Renker | f17a37c | 2010-11-10 21:20:07 +0100 | [diff] [blame] | 246 | if (++cur_head == buf_end) |
| 247 | cur_head = av->av_buf; |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 248 | } |
| 249 | } |
| 250 | |
Gerrit Renker | a47c510 | 2007-12-30 04:19:31 -0800 | [diff] [blame] | 251 | av->av_buf_ackno = ackno; |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 252 | out: |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 253 | return 0; |
| 254 | |
| 255 | out_duplicate: |
| 256 | /* Duplicate packet */ |
| 257 | dccp_pr_debug("Received a dup or already considered lost " |
| 258 | "packet: %llu\n", (unsigned long long)ackno); |
| 259 | return -EILSEQ; |
| 260 | } |
| 261 | |
Andrea Bittau | 02bcf28 | 2006-03-20 17:19:55 -0800 | [diff] [blame] | 262 | static void dccp_ackvec_throw_record(struct dccp_ackvec *av, |
| 263 | struct dccp_ackvec_record *avr) |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 264 | { |
Andrea Bittau | 02bcf28 | 2006-03-20 17:19:55 -0800 | [diff] [blame] | 265 | struct dccp_ackvec_record *next; |
| 266 | |
Andrea Bittau | 23d06e3 | 2006-09-19 13:04:54 -0700 | [diff] [blame] | 267 | /* sort out vector length */ |
Gerrit Renker | a47c510 | 2007-12-30 04:19:31 -0800 | [diff] [blame] | 268 | if (av->av_buf_head <= avr->avr_ack_ptr) |
| 269 | av->av_vec_len = avr->avr_ack_ptr - av->av_buf_head; |
Andrea Bittau | 23d06e3 | 2006-09-19 13:04:54 -0700 | [diff] [blame] | 270 | else |
Gerrit Renker | f17a37c | 2010-11-10 21:20:07 +0100 | [diff] [blame] | 271 | av->av_vec_len = DCCPAV_MAX_ACKVEC_LEN - 1 - |
Gerrit Renker | a47c510 | 2007-12-30 04:19:31 -0800 | [diff] [blame] | 272 | av->av_buf_head + avr->avr_ack_ptr; |
Andrea Bittau | 02bcf28 | 2006-03-20 17:19:55 -0800 | [diff] [blame] | 273 | |
| 274 | /* free records */ |
Gerrit Renker | a47c510 | 2007-12-30 04:19:31 -0800 | [diff] [blame] | 275 | list_for_each_entry_safe_from(avr, next, &av->av_records, avr_node) { |
Gerrit Renker | f17a37c | 2010-11-10 21:20:07 +0100 | [diff] [blame] | 276 | list_del(&avr->avr_node); |
| 277 | kmem_cache_free(dccp_ackvec_record_slab, avr); |
Andrea Bittau | 02bcf28 | 2006-03-20 17:19:55 -0800 | [diff] [blame] | 278 | } |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 279 | } |
| 280 | |
| 281 | void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av, struct sock *sk, |
| 282 | const u64 ackno) |
| 283 | { |
Andrea Bittau | 02bcf28 | 2006-03-20 17:19:55 -0800 | [diff] [blame] | 284 | struct dccp_ackvec_record *avr; |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 285 | |
Andrea Bittau | 02bcf28 | 2006-03-20 17:19:55 -0800 | [diff] [blame] | 286 | /* |
| 287 | * If we traverse backwards, it should be faster when we have large |
| 288 | * windows. We will be receiving ACKs for stuff we sent a while back |
| 289 | * -sorbo. |
| 290 | */ |
Gerrit Renker | a47c510 | 2007-12-30 04:19:31 -0800 | [diff] [blame] | 291 | list_for_each_entry_reverse(avr, &av->av_records, avr_node) { |
| 292 | if (ackno == avr->avr_ack_seqno) { |
Gerrit Renker | 09dbc38 | 2006-11-14 12:57:34 -0200 | [diff] [blame] | 293 | dccp_pr_debug("%s ACK packet 0, len=%d, ack_seqno=%llu, " |
Andrea Bittau | 02bcf28 | 2006-03-20 17:19:55 -0800 | [diff] [blame] | 294 | "ack_ackno=%llu, ACKED!\n", |
Gerrit Renker | f17a37c | 2010-11-10 21:20:07 +0100 | [diff] [blame] | 295 | dccp_role(sk), avr->avr_ack_runlen, |
Gerrit Renker | a47c510 | 2007-12-30 04:19:31 -0800 | [diff] [blame] | 296 | (unsigned long long)avr->avr_ack_seqno, |
| 297 | (unsigned long long)avr->avr_ack_ackno); |
Andrea Bittau | 02bcf28 | 2006-03-20 17:19:55 -0800 | [diff] [blame] | 298 | dccp_ackvec_throw_record(av, avr); |
| 299 | break; |
Gerrit Renker | a47c510 | 2007-12-30 04:19:31 -0800 | [diff] [blame] | 300 | } else if (avr->avr_ack_seqno > ackno) |
Andrea Bittau | d23ca15 | 2006-11-14 13:19:45 -0200 | [diff] [blame] | 301 | break; /* old news */ |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 302 | } |
| 303 | } |
| 304 | |
| 305 | static void dccp_ackvec_check_rcv_ackvector(struct dccp_ackvec *av, |
Andrea Bittau | bdf13d2 | 2006-11-24 13:02:42 -0200 | [diff] [blame] | 306 | struct sock *sk, u64 *ackno, |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 307 | const unsigned char len, |
| 308 | const unsigned char *vector) |
| 309 | { |
| 310 | unsigned char i; |
Andrea Bittau | 02bcf28 | 2006-03-20 17:19:55 -0800 | [diff] [blame] | 311 | struct dccp_ackvec_record *avr; |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 312 | |
| 313 | /* Check if we actually sent an ACK vector */ |
Gerrit Renker | a47c510 | 2007-12-30 04:19:31 -0800 | [diff] [blame] | 314 | if (list_empty(&av->av_records)) |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 315 | return; |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 316 | |
| 317 | i = len; |
Andrea Bittau | 02bcf28 | 2006-03-20 17:19:55 -0800 | [diff] [blame] | 318 | /* |
| 319 | * XXX |
| 320 | * I think it might be more efficient to work backwards. See comment on |
| 321 | * rcv_ackno. -sorbo. |
| 322 | */ |
Gerrit Renker | a47c510 | 2007-12-30 04:19:31 -0800 | [diff] [blame] | 323 | avr = list_entry(av->av_records.next, struct dccp_ackvec_record, avr_node); |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 324 | while (i--) { |
Gerrit Renker | f17a37c | 2010-11-10 21:20:07 +0100 | [diff] [blame] | 325 | const u8 rl = dccp_ackvec_runlen(vector); |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 326 | u64 ackno_end_rl; |
| 327 | |
Andrea Bittau | bdf13d2 | 2006-11-24 13:02:42 -0200 | [diff] [blame] | 328 | dccp_set_seqno(&ackno_end_rl, *ackno - rl); |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 329 | |
| 330 | /* |
Andrea Bittau | 02bcf28 | 2006-03-20 17:19:55 -0800 | [diff] [blame] | 331 | * If our AVR sequence number is greater than the ack, go |
| 332 | * forward in the AVR list until it is not so. |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 333 | */ |
Gerrit Renker | a47c510 | 2007-12-30 04:19:31 -0800 | [diff] [blame] | 334 | list_for_each_entry_from(avr, &av->av_records, avr_node) { |
| 335 | if (!after48(avr->avr_ack_seqno, *ackno)) |
Andrea Bittau | 02bcf28 | 2006-03-20 17:19:55 -0800 | [diff] [blame] | 336 | goto found; |
| 337 | } |
Gerrit Renker | a47c510 | 2007-12-30 04:19:31 -0800 | [diff] [blame] | 338 | /* End of the av_records list, not found, exit */ |
Andrea Bittau | 02bcf28 | 2006-03-20 17:19:55 -0800 | [diff] [blame] | 339 | break; |
| 340 | found: |
Gerrit Renker | a47c510 | 2007-12-30 04:19:31 -0800 | [diff] [blame] | 341 | if (between48(avr->avr_ack_seqno, ackno_end_rl, *ackno)) { |
Gerrit Renker | f17a37c | 2010-11-10 21:20:07 +0100 | [diff] [blame] | 342 | if (dccp_ackvec_state(vector) != DCCPAV_NOT_RECEIVED) { |
Gerrit Renker | 09dbc38 | 2006-11-14 12:57:34 -0200 | [diff] [blame] | 343 | dccp_pr_debug("%s ACK vector 0, len=%d, " |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 344 | "ack_seqno=%llu, ack_ackno=%llu, " |
| 345 | "ACKED!\n", |
Gerrit Renker | 09dbc38 | 2006-11-14 12:57:34 -0200 | [diff] [blame] | 346 | dccp_role(sk), len, |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 347 | (unsigned long long) |
Gerrit Renker | a47c510 | 2007-12-30 04:19:31 -0800 | [diff] [blame] | 348 | avr->avr_ack_seqno, |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 349 | (unsigned long long) |
Gerrit Renker | a47c510 | 2007-12-30 04:19:31 -0800 | [diff] [blame] | 350 | avr->avr_ack_ackno); |
Andrea Bittau | 02bcf28 | 2006-03-20 17:19:55 -0800 | [diff] [blame] | 351 | dccp_ackvec_throw_record(av, avr); |
Andrea Bittau | afec35e | 2006-06-11 20:58:33 -0700 | [diff] [blame] | 352 | break; |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 353 | } |
| 354 | /* |
Andrea Bittau | 02bcf28 | 2006-03-20 17:19:55 -0800 | [diff] [blame] | 355 | * If it wasn't received, continue scanning... we might |
| 356 | * find another one. |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 357 | */ |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 358 | } |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 359 | |
Andrea Bittau | bdf13d2 | 2006-11-24 13:02:42 -0200 | [diff] [blame] | 360 | dccp_set_seqno(ackno, ackno_end_rl - 1); |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 361 | ++vector; |
| 362 | } |
| 363 | } |
| 364 | |
| 365 | int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb, |
Andrea Bittau | bdf13d2 | 2006-11-24 13:02:42 -0200 | [diff] [blame] | 366 | u64 *ackno, const u8 opt, const u8 *value, const u8 len) |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 367 | { |
Gerrit Renker | b20a9c2 | 2008-11-23 16:02:31 -0800 | [diff] [blame] | 368 | if (len > DCCP_SINGLE_OPT_MAXLEN) |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 369 | return -1; |
| 370 | |
| 371 | /* dccp_ackvector_print(DCCP_SKB_CB(skb)->dccpd_ack_seq, value, len); */ |
| 372 | dccp_ackvec_check_rcv_ackvector(dccp_sk(sk)->dccps_hc_rx_ackvec, sk, |
Andrea Bittau | bdf13d2 | 2006-11-24 13:02:42 -0200 | [diff] [blame] | 373 | ackno, len, value); |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 374 | return 0; |
| 375 | } |
Arnaldo Carvalho de Melo | 9b07ef5 | 2006-03-20 17:16:17 -0800 | [diff] [blame] | 376 | |
Gerrit Renker | 5753fdf | 2010-11-14 17:25:11 +0100 | [diff] [blame^] | 377 | /** |
| 378 | * dccp_ackvec_clear_state - Perform house-keeping / garbage-collection |
| 379 | * This routine is called when the peer acknowledges the receipt of Ack Vectors |
| 380 | * up to and including @ackno. While based on on section A.3 of RFC 4340, here |
| 381 | * are additional precautions to prevent corrupted buffer state. In particular, |
| 382 | * we use tail_ackno to identify outdated records; it always marks the earliest |
| 383 | * packet of group (2) in 11.4.2. |
| 384 | */ |
| 385 | void dccp_ackvec_clear_state(struct dccp_ackvec *av, const u64 ackno) |
| 386 | { |
| 387 | struct dccp_ackvec_record *avr, *next; |
| 388 | u8 runlen_now, eff_runlen; |
| 389 | s64 delta; |
| 390 | |
| 391 | avr = dccp_ackvec_lookup(&av->av_records, ackno); |
| 392 | if (avr == NULL) |
| 393 | return; |
| 394 | /* |
| 395 | * Deal with outdated acknowledgments: this arises when e.g. there are |
| 396 | * several old records and the acks from the peer come in slowly. In |
| 397 | * that case we may still have records that pre-date tail_ackno. |
| 398 | */ |
| 399 | delta = dccp_delta_seqno(av->av_tail_ackno, avr->avr_ack_ackno); |
| 400 | if (delta < 0) |
| 401 | goto free_records; |
| 402 | /* |
| 403 | * Deal with overlapping Ack Vectors: don't subtract more than the |
| 404 | * number of packets between tail_ackno and ack_ackno. |
| 405 | */ |
| 406 | eff_runlen = delta < avr->avr_ack_runlen ? delta : avr->avr_ack_runlen; |
| 407 | |
| 408 | runlen_now = dccp_ackvec_runlen(av->av_buf + avr->avr_ack_ptr); |
| 409 | /* |
| 410 | * The run length of Ack Vector cells does not decrease over time. If |
| 411 | * the run length is the same as at the time the Ack Vector was sent, we |
| 412 | * free the ack_ptr cell. That cell can however not be freed if the run |
| 413 | * length has increased: in this case we need to move the tail pointer |
| 414 | * backwards (towards higher indices), to its next-oldest neighbour. |
| 415 | */ |
| 416 | if (runlen_now > eff_runlen) { |
| 417 | |
| 418 | av->av_buf[avr->avr_ack_ptr] -= eff_runlen + 1; |
| 419 | av->av_buf_tail = __ackvec_idx_add(avr->avr_ack_ptr, 1); |
| 420 | |
| 421 | /* This move may not have cleared the overflow flag. */ |
| 422 | if (av->av_overflow) |
| 423 | av->av_overflow = (av->av_buf_head == av->av_buf_tail); |
| 424 | } else { |
| 425 | av->av_buf_tail = avr->avr_ack_ptr; |
| 426 | /* |
| 427 | * We have made sure that avr points to a valid cell within the |
| 428 | * buffer. This cell is either older than head, or equals head |
| 429 | * (empty buffer): in both cases we no longer have any overflow. |
| 430 | */ |
| 431 | av->av_overflow = 0; |
| 432 | } |
| 433 | |
| 434 | /* |
| 435 | * The peer has acknowledged up to and including ack_ackno. Hence the |
| 436 | * first packet in group (2) of 11.4.2 is the successor of ack_ackno. |
| 437 | */ |
| 438 | av->av_tail_ackno = ADD48(avr->avr_ack_ackno, 1); |
| 439 | |
| 440 | free_records: |
| 441 | list_for_each_entry_safe_from(avr, next, &av->av_records, avr_node) { |
| 442 | list_del(&avr->avr_node); |
| 443 | kmem_cache_free(dccp_ackvec_record_slab, avr); |
| 444 | } |
| 445 | } |
| 446 | |
Arnaldo Carvalho de Melo | 9b07ef5 | 2006-03-20 17:16:17 -0800 | [diff] [blame] | 447 | int __init dccp_ackvec_init(void) |
| 448 | { |
| 449 | dccp_ackvec_slab = kmem_cache_create("dccp_ackvec", |
| 450 | sizeof(struct dccp_ackvec), 0, |
Paul Mundt | 20c2df8 | 2007-07-20 10:11:58 +0900 | [diff] [blame] | 451 | SLAB_HWCACHE_ALIGN, NULL); |
Andrea Bittau | 02bcf28 | 2006-03-20 17:19:55 -0800 | [diff] [blame] | 452 | if (dccp_ackvec_slab == NULL) |
| 453 | goto out_err; |
| 454 | |
Gerrit Renker | f17a37c | 2010-11-10 21:20:07 +0100 | [diff] [blame] | 455 | dccp_ackvec_record_slab = kmem_cache_create("dccp_ackvec_record", |
| 456 | sizeof(struct dccp_ackvec_record), |
| 457 | 0, SLAB_HWCACHE_ALIGN, NULL); |
Andrea Bittau | 02bcf28 | 2006-03-20 17:19:55 -0800 | [diff] [blame] | 458 | if (dccp_ackvec_record_slab == NULL) |
| 459 | goto out_destroy_slab; |
Arnaldo Carvalho de Melo | 9b07ef5 | 2006-03-20 17:16:17 -0800 | [diff] [blame] | 460 | |
| 461 | return 0; |
Andrea Bittau | 02bcf28 | 2006-03-20 17:19:55 -0800 | [diff] [blame] | 462 | |
| 463 | out_destroy_slab: |
| 464 | kmem_cache_destroy(dccp_ackvec_slab); |
| 465 | dccp_ackvec_slab = NULL; |
| 466 | out_err: |
Gerrit Renker | 59348b1 | 2006-11-20 18:39:23 -0200 | [diff] [blame] | 467 | DCCP_CRIT("Unable to create Ack Vector slab cache"); |
Andrea Bittau | 02bcf28 | 2006-03-20 17:19:55 -0800 | [diff] [blame] | 468 | return -ENOBUFS; |
Arnaldo Carvalho de Melo | 9b07ef5 | 2006-03-20 17:16:17 -0800 | [diff] [blame] | 469 | } |
| 470 | |
| 471 | void dccp_ackvec_exit(void) |
| 472 | { |
| 473 | if (dccp_ackvec_slab != NULL) { |
| 474 | kmem_cache_destroy(dccp_ackvec_slab); |
| 475 | dccp_ackvec_slab = NULL; |
| 476 | } |
Andrea Bittau | 02bcf28 | 2006-03-20 17:19:55 -0800 | [diff] [blame] | 477 | if (dccp_ackvec_record_slab != NULL) { |
| 478 | kmem_cache_destroy(dccp_ackvec_record_slab); |
| 479 | dccp_ackvec_record_slab = NULL; |
| 480 | } |
Arnaldo Carvalho de Melo | 9b07ef5 | 2006-03-20 17:16:17 -0800 | [diff] [blame] | 481 | } |