1 /* SCTP kernel implementation 2 * (C) Copyright IBM Corp. 2003, 2004 3 * 4 * This file is part of the SCTP kernel implementation 5 * 6 * This file contains the code relating the chunk abstraction. 7 * 8 * This SCTP implementation is free software; 9 * you can redistribute it and/or modify it under the terms of 10 * the GNU General Public License as published by 11 * the Free Software Foundation; either version 2, or (at your option) 12 * any later version. 13 * 14 * This SCTP implementation is distributed in the hope that it 15 * will be useful, but WITHOUT ANY WARRANTY; without even the implied 16 * ************************ 17 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 18 * See the GNU General Public License for more details. 19 * 20 * You should have received a copy of the GNU General Public License 21 * along with GNU CC; see the file COPYING. If not, write to 22 * the Free Software Foundation, 59 Temple Place - Suite 330, 23 * Boston, MA 02111-1307, USA. 24 * 25 * Please send any bug reports or fixes you make to the 26 * email address(es): 27 * lksctp developers <lksctp-developers@lists.sourceforge.net> 28 * 29 * Or submit a bug report through the following website: 30 * http://www.sf.net/projects/lksctp 31 * 32 * Written or modified by: 33 * Jon Grimm <jgrimm@us.ibm.com> 34 * Sridhar Samudrala <sri@us.ibm.com> 35 * 36 * Any bugs reported given to us we will try to fix... any fixes shared will 37 * be incorporated into the next SCTP release. 38 */ 39 40 #include <linux/types.h> 41 #include <linux/kernel.h> 42 #include <linux/net.h> 43 #include <linux/inet.h> 44 #include <linux/skbuff.h> 45 #include <linux/slab.h> 46 #include <net/sock.h> 47 #include <net/sctp/sctp.h> 48 #include <net/sctp/sm.h> 49 50 /* This file is mostly in anticipation of future work, but initially 51 * populate with fragment tracking for an outbound message. 52 */ 53 54 /* Initialize datamsg from memory. */ 55 static void sctp_datamsg_init(struct sctp_datamsg *msg) 56 { 57 atomic_set(&msg->refcnt, 1); 58 msg->send_failed = 0; 59 msg->send_error = 0; 60 msg->can_abandon = 0; 61 msg->expires_at = 0; 62 INIT_LIST_HEAD(&msg->chunks); 63 msg->msg_size = 0; 64 } 65 66 /* Allocate and initialize datamsg. */ 67 SCTP_STATIC struct sctp_datamsg *sctp_datamsg_new(gfp_t gfp) 68 { 69 struct sctp_datamsg *msg; 70 msg = kmalloc(sizeof(struct sctp_datamsg), gfp); 71 if (msg) { 72 sctp_datamsg_init(msg); 73 SCTP_DBG_OBJCNT_INC(datamsg); 74 } 75 return msg; 76 } 77 78 void sctp_datamsg_free(struct sctp_datamsg *msg) 79 { 80 struct sctp_chunk *chunk; 81 82 /* This doesn't have to be a _safe vairant because 83 * sctp_chunk_free() only drops the refs. 84 */ 85 list_for_each_entry(chunk, &msg->chunks, frag_list) 86 sctp_chunk_free(chunk); 87 88 sctp_datamsg_put(msg); 89 } 90 91 /* Final destructruction of datamsg memory. */ 92 static void sctp_datamsg_destroy(struct sctp_datamsg *msg) 93 { 94 struct list_head *pos, *temp; 95 struct sctp_chunk *chunk; 96 struct sctp_sock *sp; 97 struct sctp_ulpevent *ev; 98 struct sctp_association *asoc = NULL; 99 int error = 0, notify; 100 101 /* If we failed, we may need to notify. */ 102 notify = msg->send_failed ? -1 : 0; 103 104 /* Release all references. */ 105 list_for_each_safe(pos, temp, &msg->chunks) { 106 list_del_init(pos); 107 chunk = list_entry(pos, struct sctp_chunk, frag_list); 108 /* Check whether we _really_ need to notify. */ 109 if (notify < 0) { 110 asoc = chunk->asoc; 111 if (msg->send_error) 112 error = msg->send_error; 113 else 114 error = asoc->outqueue.error; 115 116 sp = sctp_sk(asoc->base.sk); 117 notify = sctp_ulpevent_type_enabled(SCTP_SEND_FAILED, 118 &sp->subscribe); 119 } 120 121 /* Generate a SEND FAILED event only if enabled. */ 122 if (notify > 0) { 123 int sent; 124 if (chunk->has_tsn) 125 sent = SCTP_DATA_SENT; 126 else 127 sent = SCTP_DATA_UNSENT; 128 129 ev = sctp_ulpevent_make_send_failed(asoc, chunk, sent, 130 error, GFP_ATOMIC); 131 if (ev) 132 sctp_ulpq_tail_event(&asoc->ulpq, ev); 133 } 134 135 sctp_chunk_put(chunk); 136 } 137 138 SCTP_DBG_OBJCNT_DEC(datamsg); 139 kfree(msg); 140 } 141 142 /* Hold a reference. */ 143 static void sctp_datamsg_hold(struct sctp_datamsg *msg) 144 { 145 atomic_inc(&msg->refcnt); 146 } 147 148 /* Release a reference. */ 149 void sctp_datamsg_put(struct sctp_datamsg *msg) 150 { 151 if (atomic_dec_and_test(&msg->refcnt)) 152 sctp_datamsg_destroy(msg); 153 } 154 155 /* Assign a chunk to this datamsg. */ 156 static void sctp_datamsg_assign(struct sctp_datamsg *msg, struct sctp_chunk *chunk) 157 { 158 sctp_datamsg_hold(msg); 159 chunk->msg = msg; 160 msg->msg_size += chunk->skb->len; 161 } 162 163 164 /* A data chunk can have a maximum payload of (2^16 - 20). Break 165 * down any such message into smaller chunks. Opportunistically, fragment 166 * the chunks down to the current MTU constraints. We may get refragmented 167 * later if the PMTU changes, but it is _much better_ to fragment immediately 168 * with a reasonable guess than always doing our fragmentation on the 169 * soft-interrupt. 170 */ 171 struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc, 172 struct sctp_sndrcvinfo *sinfo, 173 struct msghdr *msgh, int msg_len) 174 { 175 int max, whole, i, offset, over, err; 176 int len, first_len; 177 int max_data; 178 struct sctp_chunk *chunk; 179 struct sctp_datamsg *msg; 180 struct list_head *pos, *temp; 181 __u8 frag; 182 183 msg = sctp_datamsg_new(GFP_KERNEL); 184 if (!msg) 185 return NULL; 186 187 /* Note: Calculate this outside of the loop, so that all fragments 188 * have the same expiration. 189 */ 190 if (sinfo->sinfo_timetolive) { 191 /* sinfo_timetolive is in milliseconds */ 192 msg->expires_at = jiffies + 193 msecs_to_jiffies(sinfo->sinfo_timetolive); 194 msg->can_abandon = 1; 195 SCTP_DEBUG_PRINTK("%s: msg:%p expires_at: %ld jiffies:%ld\n", 196 __func__, msg, msg->expires_at, jiffies); 197 } 198 199 /* This is the biggest possible DATA chunk that can fit into 200 * the packet 201 */ 202 max_data = asoc->pathmtu - 203 sctp_sk(asoc->base.sk)->pf->af->net_header_len - 204 sizeof(struct sctphdr) - sizeof(struct sctp_data_chunk); 205 206 max = asoc->frag_point; 207 /* If the the peer requested that we authenticate DATA chunks 208 * we need to accound for bundling of the AUTH chunks along with 209 * DATA. 210 */ 211 if (sctp_auth_send_cid(SCTP_CID_DATA, asoc)) { 212 struct sctp_hmac *hmac_desc = sctp_auth_asoc_get_hmac(asoc); 213 214 if (hmac_desc) 215 max_data -= WORD_ROUND(sizeof(sctp_auth_chunk_t) + 216 hmac_desc->hmac_len); 217 } 218 219 /* Now, check if we need to reduce our max */ 220 if (max > max_data) 221 max = max_data; 222 223 whole = 0; 224 first_len = max; 225 226 /* Check to see if we have a pending SACK and try to let it be bundled 227 * with this message. Do this if we don't have any data queued already. 228 * To check that, look at out_qlen and retransmit list. 229 * NOTE: we will not reduce to account for SACK, if the message would 230 * not have been fragmented. 231 */ 232 if (timer_pending(&asoc->timers[SCTP_EVENT_TIMEOUT_SACK]) && 233 asoc->outqueue.out_qlen == 0 && 234 list_empty(&asoc->outqueue.retransmit) && 235 msg_len > max) 236 max_data -= WORD_ROUND(sizeof(sctp_sack_chunk_t)); 237 238 /* Encourage Cookie-ECHO bundling. */ 239 if (asoc->state < SCTP_STATE_COOKIE_ECHOED) 240 max_data -= SCTP_ARBITRARY_COOKIE_ECHO_LEN; 241 242 /* Now that we adjusted completely, reset first_len */ 243 if (first_len > max_data) 244 first_len = max_data; 245 246 /* Account for a different sized first fragment */ 247 if (msg_len >= first_len) { 248 msg_len -= first_len; 249 whole = 1; 250 } 251 252 /* How many full sized? How many bytes leftover? */ 253 whole += msg_len / max; 254 over = msg_len % max; 255 offset = 0; 256 257 if ((whole > 1) || (whole && over)) 258 SCTP_INC_STATS_USER(SCTP_MIB_FRAGUSRMSGS); 259 260 /* Create chunks for all the full sized DATA chunks. */ 261 for (i=0, len=first_len; i < whole; i++) { 262 frag = SCTP_DATA_MIDDLE_FRAG; 263 264 if (0 == i) 265 frag |= SCTP_DATA_FIRST_FRAG; 266 267 if ((i == (whole - 1)) && !over) { 268 frag |= SCTP_DATA_LAST_FRAG; 269 270 /* The application requests to set the I-bit of the 271 * last DATA chunk of a user message when providing 272 * the user message to the SCTP implementation. 273 */ 274 if ((sinfo->sinfo_flags & SCTP_EOF) || 275 (sinfo->sinfo_flags & SCTP_SACK_IMMEDIATELY)) 276 frag |= SCTP_DATA_SACK_IMM; 277 } 278 279 chunk = sctp_make_datafrag_empty(asoc, sinfo, len, frag, 0); 280 281 if (!chunk) 282 goto errout; 283 err = sctp_user_addto_chunk(chunk, offset, len, msgh->msg_iov); 284 if (err < 0) 285 goto errout; 286 287 offset += len; 288 289 /* Put the chunk->skb back into the form expected by send. */ 290 __skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr 291 - (__u8 *)chunk->skb->data); 292 293 sctp_datamsg_assign(msg, chunk); 294 list_add_tail(&chunk->frag_list, &msg->chunks); 295 296 /* The first chunk, the first chunk was likely short 297 * to allow bundling, so reset to full size. 298 */ 299 if (0 == i) 300 len = max; 301 } 302 303 /* .. now the leftover bytes. */ 304 if (over) { 305 if (!whole) 306 frag = SCTP_DATA_NOT_FRAG; 307 else 308 frag = SCTP_DATA_LAST_FRAG; 309 310 if ((sinfo->sinfo_flags & SCTP_EOF) || 311 (sinfo->sinfo_flags & SCTP_SACK_IMMEDIATELY)) 312 frag |= SCTP_DATA_SACK_IMM; 313 314 chunk = sctp_make_datafrag_empty(asoc, sinfo, over, frag, 0); 315 316 if (!chunk) 317 goto errout; 318 319 err = sctp_user_addto_chunk(chunk, offset, over,msgh->msg_iov); 320 321 /* Put the chunk->skb back into the form expected by send. */ 322 __skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr 323 - (__u8 *)chunk->skb->data); 324 if (err < 0) 325 goto errout; 326 327 sctp_datamsg_assign(msg, chunk); 328 list_add_tail(&chunk->frag_list, &msg->chunks); 329 } 330 331 return msg; 332 333 errout: 334 list_for_each_safe(pos, temp, &msg->chunks) { 335 list_del_init(pos); 336 chunk = list_entry(pos, struct sctp_chunk, frag_list); 337 sctp_chunk_free(chunk); 338 } 339 sctp_datamsg_put(msg); 340 return NULL; 341 } 342 343 /* Check whether this message has expired. */ 344 int sctp_chunk_abandoned(struct sctp_chunk *chunk) 345 { 346 struct sctp_datamsg *msg = chunk->msg; 347 348 if (!msg->can_abandon) 349 return 0; 350 351 if (time_after(jiffies, msg->expires_at)) 352 return 1; 353 354 return 0; 355 } 356 357 /* This chunk (and consequently entire message) has failed in its sending. */ 358 void sctp_chunk_fail(struct sctp_chunk *chunk, int error) 359 { 360 chunk->msg->send_failed = 1; 361 chunk->msg->send_error = error; 362 } 363