Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 1 | /* |
| 2 | * net/dccp/ackvec.c |
| 3 | * |
| 4 | * An implementation of the DCCP protocol |
| 5 | * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@ghostprotocols.net> |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify it |
| 8 | * under the terms of the GNU General Public License as published by the |
| 9 | * Free Software Foundation; version 2 of the License; |
| 10 | */ |
| 11 | |
| 12 | #include "ackvec.h" |
| 13 | #include "dccp.h" |
| 14 | |
| 15 | #include <linux/dccp.h> |
| 16 | #include <linux/skbuff.h> |
| 17 | |
| 18 | #include <net/sock.h> |
| 19 | |
| 20 | int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb) |
| 21 | { |
| 22 | struct dccp_sock *dp = dccp_sk(sk); |
| 23 | struct dccp_ackvec *av = dp->dccps_hc_rx_ackvec; |
| 24 | int len = av->dccpav_vec_len + 2; |
| 25 | struct timeval now; |
| 26 | u32 elapsed_time; |
| 27 | unsigned char *to, *from; |
| 28 | |
| 29 | dccp_timestamp(sk, &now); |
| 30 | elapsed_time = timeval_delta(&now, &av->dccpav_time) / 10; |
| 31 | |
| 32 | if (elapsed_time != 0) |
| 33 | dccp_insert_option_elapsed_time(sk, skb, elapsed_time); |
| 34 | |
| 35 | if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) |
| 36 | return -1; |
| 37 | |
| 38 | /* |
| 39 | * XXX: now we have just one ack vector sent record, so |
| 40 | * we have to wait for it to be cleared. |
| 41 | * |
| 42 | * Of course this is not acceptable, but this is just for |
| 43 | * basic testing now. |
| 44 | */ |
| 45 | if (av->dccpav_ack_seqno != DCCP_MAX_SEQNO + 1) |
| 46 | return -1; |
| 47 | |
| 48 | DCCP_SKB_CB(skb)->dccpd_opt_len += len; |
| 49 | |
| 50 | to = skb_push(skb, len); |
| 51 | *to++ = DCCPO_ACK_VECTOR_0; |
| 52 | *to++ = len; |
| 53 | |
| 54 | len = av->dccpav_vec_len; |
| 55 | from = av->dccpav_buf + av->dccpav_buf_head; |
| 56 | |
| 57 | /* Check if buf_head wraps */ |
Arnaldo Carvalho de Melo | e4dfd44 | 2006-01-04 01:46:34 -0200 | [diff] [blame] | 58 | if ((int)av->dccpav_buf_head + len > av->dccpav_vec_len) { |
| 59 | const u32 tailsize = av->dccpav_vec_len - av->dccpav_buf_head; |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 60 | |
| 61 | memcpy(to, from, tailsize); |
| 62 | to += tailsize; |
| 63 | len -= tailsize; |
| 64 | from = av->dccpav_buf; |
| 65 | } |
| 66 | |
| 67 | memcpy(to, from, len); |
| 68 | /* |
| 69 | * From draft-ietf-dccp-spec-11.txt: |
| 70 | * |
| 71 | * For each acknowledgement it sends, the HC-Receiver will add an |
| 72 | * acknowledgement record. ack_seqno will equal the HC-Receiver |
| 73 | * sequence number it used for the ack packet; ack_ptr will equal |
| 74 | * buf_head; ack_ackno will equal buf_ackno; and ack_nonce will |
| 75 | * equal buf_nonce. |
| 76 | * |
| 77 | * This implemention uses just one ack record for now. |
| 78 | */ |
| 79 | av->dccpav_ack_seqno = DCCP_SKB_CB(skb)->dccpd_seq; |
| 80 | av->dccpav_ack_ptr = av->dccpav_buf_head; |
| 81 | av->dccpav_ack_ackno = av->dccpav_buf_ackno; |
| 82 | av->dccpav_ack_nonce = av->dccpav_buf_nonce; |
| 83 | av->dccpav_sent_len = av->dccpav_vec_len; |
| 84 | |
| 85 | dccp_pr_debug("%sACK Vector 0, len=%d, ack_seqno=%llu, " |
| 86 | "ack_ackno=%llu\n", |
| 87 | debug_prefix, av->dccpav_sent_len, |
| 88 | (unsigned long long)av->dccpav_ack_seqno, |
| 89 | (unsigned long long)av->dccpav_ack_ackno); |
| 90 | return -1; |
| 91 | } |
| 92 | |
| 93 | struct dccp_ackvec *dccp_ackvec_alloc(const unsigned int len, |
Al Viro | dd0fc66 | 2005-10-07 07:46:04 +0100 | [diff] [blame] | 94 | const gfp_t priority) |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 95 | { |
Arnaldo Carvalho de Melo | e4dfd44 | 2006-01-04 01:46:34 -0200 | [diff] [blame] | 96 | struct dccp_ackvec *av; |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 97 | |
Arnaldo Carvalho de Melo | e4dfd44 | 2006-01-04 01:46:34 -0200 | [diff] [blame] | 98 | BUG_ON(len == 0); |
| 99 | |
| 100 | if (len > DCCP_MAX_ACKVEC_LEN) |
| 101 | return NULL; |
| 102 | |
| 103 | av = kmalloc(sizeof(*av) + len, priority); |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 104 | if (av != NULL) { |
| 105 | av->dccpav_buf_len = len; |
| 106 | av->dccpav_buf_head = |
| 107 | av->dccpav_buf_tail = av->dccpav_buf_len - 1; |
| 108 | av->dccpav_buf_ackno = |
| 109 | av->dccpav_ack_ackno = av->dccpav_ack_seqno = ~0LLU; |
| 110 | av->dccpav_buf_nonce = av->dccpav_buf_nonce = 0; |
| 111 | av->dccpav_ack_ptr = 0; |
| 112 | av->dccpav_time.tv_sec = 0; |
| 113 | av->dccpav_time.tv_usec = 0; |
| 114 | av->dccpav_sent_len = av->dccpav_vec_len = 0; |
| 115 | } |
| 116 | |
| 117 | return av; |
| 118 | } |
| 119 | |
| 120 | void dccp_ackvec_free(struct dccp_ackvec *av) |
| 121 | { |
| 122 | kfree(av); |
| 123 | } |
| 124 | |
| 125 | static inline u8 dccp_ackvec_state(const struct dccp_ackvec *av, |
Arnaldo Carvalho de Melo | e4dfd44 | 2006-01-04 01:46:34 -0200 | [diff] [blame] | 126 | const u8 index) |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 127 | { |
| 128 | return av->dccpav_buf[index] & DCCP_ACKVEC_STATE_MASK; |
| 129 | } |
| 130 | |
| 131 | static inline u8 dccp_ackvec_len(const struct dccp_ackvec *av, |
Arnaldo Carvalho de Melo | e4dfd44 | 2006-01-04 01:46:34 -0200 | [diff] [blame] | 132 | const u8 index) |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 133 | { |
| 134 | return av->dccpav_buf[index] & DCCP_ACKVEC_LEN_MASK; |
| 135 | } |
| 136 | |
| 137 | /* |
| 138 | * If several packets are missing, the HC-Receiver may prefer to enter multiple |
| 139 | * bytes with run length 0, rather than a single byte with a larger run length; |
| 140 | * this simplifies table updates if one of the missing packets arrives. |
| 141 | */ |
| 142 | static inline int dccp_ackvec_set_buf_head_state(struct dccp_ackvec *av, |
| 143 | const unsigned int packets, |
Arnaldo Carvalho de Melo | e4dfd44 | 2006-01-04 01:46:34 -0200 | [diff] [blame] | 144 | const unsigned char state) |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 145 | { |
| 146 | unsigned int gap; |
Kris Katterjohn | a8fc3d8 | 2006-01-17 13:03:54 -0800 | [diff] [blame^] | 147 | long new_head; |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 148 | |
| 149 | if (av->dccpav_vec_len + packets > av->dccpav_buf_len) |
| 150 | return -ENOBUFS; |
| 151 | |
| 152 | gap = packets - 1; |
| 153 | new_head = av->dccpav_buf_head - packets; |
| 154 | |
| 155 | if (new_head < 0) { |
| 156 | if (gap > 0) { |
| 157 | memset(av->dccpav_buf, DCCP_ACKVEC_STATE_NOT_RECEIVED, |
| 158 | gap + new_head + 1); |
| 159 | gap = -new_head; |
| 160 | } |
| 161 | new_head += av->dccpav_buf_len; |
| 162 | } |
| 163 | |
| 164 | av->dccpav_buf_head = new_head; |
| 165 | |
| 166 | if (gap > 0) |
| 167 | memset(av->dccpav_buf + av->dccpav_buf_head + 1, |
| 168 | DCCP_ACKVEC_STATE_NOT_RECEIVED, gap); |
| 169 | |
| 170 | av->dccpav_buf[av->dccpav_buf_head] = state; |
| 171 | av->dccpav_vec_len += packets; |
| 172 | return 0; |
| 173 | } |
| 174 | |
| 175 | /* |
| 176 | * Implements the draft-ietf-dccp-spec-11.txt Appendix A |
| 177 | */ |
| 178 | int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk, |
| 179 | const u64 ackno, const u8 state) |
| 180 | { |
| 181 | /* |
| 182 | * Check at the right places if the buffer is full, if it is, tell the |
| 183 | * caller to start dropping packets till the HC-Sender acks our ACK |
| 184 | * vectors, when we will free up space in dccpav_buf. |
| 185 | * |
| 186 | * We may well decide to do buffer compression, etc, but for now lets |
| 187 | * just drop. |
| 188 | * |
| 189 | * From Appendix A: |
| 190 | * |
| 191 | * Of course, the circular buffer may overflow, either when the |
| 192 | * HC-Sender is sending data at a very high rate, when the |
| 193 | * HC-Receiver's acknowledgements are not reaching the HC-Sender, |
| 194 | * or when the HC-Sender is forgetting to acknowledge those acks |
| 195 | * (so the HC-Receiver is unable to clean up old state). In this |
| 196 | * case, the HC-Receiver should either compress the buffer (by |
| 197 | * increasing run lengths when possible), transfer its state to |
| 198 | * a larger buffer, or, as a last resort, drop all received |
| 199 | * packets, without processing them whatsoever, until its buffer |
| 200 | * shrinks again. |
| 201 | */ |
| 202 | |
| 203 | /* See if this is the first ackno being inserted */ |
| 204 | if (av->dccpav_vec_len == 0) { |
| 205 | av->dccpav_buf[av->dccpav_buf_head] = state; |
| 206 | av->dccpav_vec_len = 1; |
| 207 | } else if (after48(ackno, av->dccpav_buf_ackno)) { |
| 208 | const u64 delta = dccp_delta_seqno(av->dccpav_buf_ackno, |
| 209 | ackno); |
| 210 | |
| 211 | /* |
| 212 | * Look if the state of this packet is the same as the |
| 213 | * previous ackno and if so if we can bump the head len. |
| 214 | */ |
| 215 | if (delta == 1 && |
| 216 | dccp_ackvec_state(av, av->dccpav_buf_head) == state && |
| 217 | (dccp_ackvec_len(av, av->dccpav_buf_head) < |
| 218 | DCCP_ACKVEC_LEN_MASK)) |
| 219 | av->dccpav_buf[av->dccpav_buf_head]++; |
| 220 | else if (dccp_ackvec_set_buf_head_state(av, delta, state)) |
| 221 | return -ENOBUFS; |
| 222 | } else { |
| 223 | /* |
| 224 | * A.1.2. Old Packets |
| 225 | * |
| 226 | * When a packet with Sequence Number S arrives, and |
| 227 | * S <= buf_ackno, the HC-Receiver will scan the table |
| 228 | * for the byte corresponding to S. (Indexing structures |
| 229 | * could reduce the complexity of this scan.) |
| 230 | */ |
| 231 | u64 delta = dccp_delta_seqno(ackno, av->dccpav_buf_ackno); |
Arnaldo Carvalho de Melo | e4dfd44 | 2006-01-04 01:46:34 -0200 | [diff] [blame] | 232 | u8 index = av->dccpav_buf_head; |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 233 | |
| 234 | while (1) { |
| 235 | const u8 len = dccp_ackvec_len(av, index); |
| 236 | const u8 state = dccp_ackvec_state(av, index); |
| 237 | /* |
| 238 | * valid packets not yet in dccpav_buf have a reserved |
| 239 | * entry, with a len equal to 0. |
| 240 | */ |
| 241 | if (state == DCCP_ACKVEC_STATE_NOT_RECEIVED && |
| 242 | len == 0 && delta == 0) { /* Found our |
| 243 | reserved seat! */ |
| 244 | dccp_pr_debug("Found %llu reserved seat!\n", |
| 245 | (unsigned long long)ackno); |
| 246 | av->dccpav_buf[index] = state; |
| 247 | goto out; |
| 248 | } |
| 249 | /* len == 0 means one packet */ |
| 250 | if (delta < len + 1) |
| 251 | goto out_duplicate; |
| 252 | |
| 253 | delta -= len + 1; |
| 254 | if (++index == av->dccpav_buf_len) |
| 255 | index = 0; |
| 256 | } |
| 257 | } |
| 258 | |
| 259 | av->dccpav_buf_ackno = ackno; |
| 260 | dccp_timestamp(sk, &av->dccpav_time); |
| 261 | out: |
| 262 | dccp_pr_debug(""); |
| 263 | return 0; |
| 264 | |
| 265 | out_duplicate: |
| 266 | /* Duplicate packet */ |
| 267 | dccp_pr_debug("Received a dup or already considered lost " |
| 268 | "packet: %llu\n", (unsigned long long)ackno); |
| 269 | return -EILSEQ; |
| 270 | } |
| 271 | |
| 272 | #ifdef CONFIG_IP_DCCP_DEBUG |
| 273 | void dccp_ackvector_print(const u64 ackno, const unsigned char *vector, int len) |
| 274 | { |
| 275 | if (!dccp_debug) |
| 276 | return; |
| 277 | |
| 278 | printk("ACK vector len=%d, ackno=%llu |", len, |
| 279 | (unsigned long long)ackno); |
| 280 | |
| 281 | while (len--) { |
| 282 | const u8 state = (*vector & DCCP_ACKVEC_STATE_MASK) >> 6; |
| 283 | const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK; |
| 284 | |
| 285 | printk("%d,%d|", state, rl); |
| 286 | ++vector; |
| 287 | } |
| 288 | |
| 289 | printk("\n"); |
| 290 | } |
| 291 | |
| 292 | void dccp_ackvec_print(const struct dccp_ackvec *av) |
| 293 | { |
| 294 | dccp_ackvector_print(av->dccpav_buf_ackno, |
| 295 | av->dccpav_buf + av->dccpav_buf_head, |
| 296 | av->dccpav_vec_len); |
| 297 | } |
| 298 | #endif |
| 299 | |
Andrea Bittau | 6742bbc | 2006-01-04 01:45:17 -0200 | [diff] [blame] | 300 | static void dccp_ackvec_throw_away_ack_record(struct dccp_ackvec *av) |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 301 | { |
| 302 | /* |
| 303 | * As we're keeping track of the ack vector size (dccpav_vec_len) and |
| 304 | * the sent ack vector size (dccpav_sent_len) we don't need |
| 305 | * dccpav_buf_tail at all, but keep this code here as in the future |
| 306 | * we'll implement a vector of ack records, as suggested in |
| 307 | * draft-ietf-dccp-spec-11.txt Appendix A. -acme |
| 308 | */ |
| 309 | #if 0 |
Arnaldo Carvalho de Melo | e4dfd44 | 2006-01-04 01:46:34 -0200 | [diff] [blame] | 310 | u32 new_buf_tail = av->dccpav_ack_ptr + 1; |
| 311 | if (new_buf_tail >= av->dccpav_vec_len) |
| 312 | new_buf_tail -= av->dccpav_vec_len; |
| 313 | av->dccpav_buf_tail = new_buf_tail; |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 314 | #endif |
| 315 | av->dccpav_vec_len -= av->dccpav_sent_len; |
| 316 | } |
| 317 | |
| 318 | void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av, struct sock *sk, |
| 319 | const u64 ackno) |
| 320 | { |
| 321 | /* Check if we actually sent an ACK vector */ |
| 322 | if (av->dccpav_ack_seqno == DCCP_MAX_SEQNO + 1) |
| 323 | return; |
| 324 | |
| 325 | if (ackno == av->dccpav_ack_seqno) { |
| 326 | #ifdef CONFIG_IP_DCCP_DEBUG |
| 327 | struct dccp_sock *dp = dccp_sk(sk); |
| 328 | const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ? |
| 329 | "CLIENT rx ack: " : "server rx ack: "; |
| 330 | #endif |
| 331 | dccp_pr_debug("%sACK packet 0, len=%d, ack_seqno=%llu, " |
| 332 | "ack_ackno=%llu, ACKED!\n", |
| 333 | debug_prefix, 1, |
| 334 | (unsigned long long)av->dccpav_ack_seqno, |
| 335 | (unsigned long long)av->dccpav_ack_ackno); |
Andrea Bittau | 6742bbc | 2006-01-04 01:45:17 -0200 | [diff] [blame] | 336 | dccp_ackvec_throw_away_ack_record(av); |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 337 | av->dccpav_ack_seqno = DCCP_MAX_SEQNO + 1; |
| 338 | } |
| 339 | } |
| 340 | |
| 341 | static void dccp_ackvec_check_rcv_ackvector(struct dccp_ackvec *av, |
| 342 | struct sock *sk, u64 ackno, |
| 343 | const unsigned char len, |
| 344 | const unsigned char *vector) |
| 345 | { |
| 346 | unsigned char i; |
| 347 | |
| 348 | /* Check if we actually sent an ACK vector */ |
| 349 | if (av->dccpav_ack_seqno == DCCP_MAX_SEQNO + 1) |
| 350 | return; |
| 351 | /* |
| 352 | * We're in the receiver half connection, so if the received an ACK |
| 353 | * vector ackno (e.g. 50) before dccpav_ack_seqno (e.g. 52), we're |
| 354 | * not interested. |
| 355 | * |
| 356 | * Extra explanation with example: |
| 357 | * |
| 358 | * if we received an ACK vector with ackno 50, it can only be acking |
| 359 | * 50, 49, 48, etc, not 52 (the seqno for the ACK vector we sent). |
| 360 | */ |
| 361 | /* dccp_pr_debug("is %llu < %llu? ", ackno, av->dccpav_ack_seqno); */ |
| 362 | if (before48(ackno, av->dccpav_ack_seqno)) { |
| 363 | /* dccp_pr_debug_cat("yes\n"); */ |
| 364 | return; |
| 365 | } |
| 366 | /* dccp_pr_debug_cat("no\n"); */ |
| 367 | |
| 368 | i = len; |
| 369 | while (i--) { |
| 370 | const u8 rl = *vector & DCCP_ACKVEC_LEN_MASK; |
| 371 | u64 ackno_end_rl; |
| 372 | |
| 373 | dccp_set_seqno(&ackno_end_rl, ackno - rl); |
| 374 | |
| 375 | /* |
| 376 | * dccp_pr_debug("is %llu <= %llu <= %llu? ", ackno_end_rl, |
| 377 | * av->dccpav_ack_seqno, ackno); |
| 378 | */ |
| 379 | if (between48(av->dccpav_ack_seqno, ackno_end_rl, ackno)) { |
| 380 | const u8 state = (*vector & |
| 381 | DCCP_ACKVEC_STATE_MASK) >> 6; |
| 382 | /* dccp_pr_debug_cat("yes\n"); */ |
| 383 | |
| 384 | if (state != DCCP_ACKVEC_STATE_NOT_RECEIVED) { |
| 385 | #ifdef CONFIG_IP_DCCP_DEBUG |
| 386 | struct dccp_sock *dp = dccp_sk(sk); |
| 387 | const char *debug_prefix = |
| 388 | dp->dccps_role == DCCP_ROLE_CLIENT ? |
| 389 | "CLIENT rx ack: " : "server rx ack: "; |
| 390 | #endif |
| 391 | dccp_pr_debug("%sACK vector 0, len=%d, " |
| 392 | "ack_seqno=%llu, ack_ackno=%llu, " |
| 393 | "ACKED!\n", |
| 394 | debug_prefix, len, |
| 395 | (unsigned long long) |
| 396 | av->dccpav_ack_seqno, |
| 397 | (unsigned long long) |
| 398 | av->dccpav_ack_ackno); |
Andrea Bittau | 6742bbc | 2006-01-04 01:45:17 -0200 | [diff] [blame] | 399 | dccp_ackvec_throw_away_ack_record(av); |
Arnaldo Carvalho de Melo | ae31c33 | 2005-09-18 00:17:51 -0700 | [diff] [blame] | 400 | } |
| 401 | /* |
| 402 | * If dccpav_ack_seqno was not received, no problem |
| 403 | * we'll send another ACK vector. |
| 404 | */ |
| 405 | av->dccpav_ack_seqno = DCCP_MAX_SEQNO + 1; |
| 406 | break; |
| 407 | } |
| 408 | /* dccp_pr_debug_cat("no\n"); */ |
| 409 | |
| 410 | dccp_set_seqno(&ackno, ackno_end_rl - 1); |
| 411 | ++vector; |
| 412 | } |
| 413 | } |
| 414 | |
| 415 | int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb, |
| 416 | const u8 opt, const u8 *value, const u8 len) |
| 417 | { |
| 418 | if (len > DCCP_MAX_ACKVEC_LEN) |
| 419 | return -1; |
| 420 | |
| 421 | /* dccp_ackvector_print(DCCP_SKB_CB(skb)->dccpd_ack_seq, value, len); */ |
| 422 | dccp_ackvec_check_rcv_ackvector(dccp_sk(sk)->dccps_hc_rx_ackvec, sk, |
| 423 | DCCP_SKB_CB(skb)->dccpd_ack_seq, |
| 424 | len, value); |
| 425 | return 0; |
| 426 | } |