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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 41 42 #include <linux/types.h> 43 #include <linux/kernel.h> 44 #include <linux/net.h> 45 #include <linux/inet.h> 46 #include <linux/skbuff.h> 47 #include <linux/slab.h> 48 #include <net/sock.h> 49 #include <net/sctp/sctp.h> 50 #include <net/sctp/sm.h> 51 52 /* This file is mostly in anticipation of future work, but initially 53 * populate with fragment tracking for an outbound message. 54 */ 55 56 /* Initialize datamsg from memory. */ 57 static void sctp_datamsg_init(struct sctp_datamsg *msg) 58 { 59 atomic_set(&msg->refcnt, 1); 60 msg->send_failed = 0; 61 msg->send_error = 0; 62 msg->can_abandon = 0; 63 msg->can_delay = 1; 64 msg->expires_at = 0; 65 INIT_LIST_HEAD(&msg->chunks); 66 } 67 68 /* Allocate and initialize datamsg. */ 69 SCTP_STATIC struct sctp_datamsg *sctp_datamsg_new(gfp_t gfp) 70 { 71 struct sctp_datamsg *msg; 72 msg = kmalloc(sizeof(struct sctp_datamsg), gfp); 73 if (msg) { 74 sctp_datamsg_init(msg); 75 SCTP_DBG_OBJCNT_INC(datamsg); 76 } 77 return msg; 78 } 79 80 void sctp_datamsg_free(struct sctp_datamsg *msg) 81 { 82 struct sctp_chunk *chunk; 83 84 /* This doesn't have to be a _safe vairant because 85 * sctp_chunk_free() only drops the refs. 86 */ 87 list_for_each_entry(chunk, &msg->chunks, frag_list) 88 sctp_chunk_free(chunk); 89 90 sctp_datamsg_put(msg); 91 } 92 93 /* Final destructruction of datamsg memory. */ 94 static void sctp_datamsg_destroy(struct sctp_datamsg *msg) 95 { 96 struct list_head *pos, *temp; 97 struct sctp_chunk *chunk; 98 struct sctp_sock *sp; 99 struct sctp_ulpevent *ev; 100 struct sctp_association *asoc = NULL; 101 int error = 0, notify; 102 103 /* If we failed, we may need to notify. */ 104 notify = msg->send_failed ? -1 : 0; 105 106 /* Release all references. */ 107 list_for_each_safe(pos, temp, &msg->chunks) { 108 list_del_init(pos); 109 chunk = list_entry(pos, struct sctp_chunk, frag_list); 110 /* Check whether we _really_ need to notify. */ 111 if (notify < 0) { 112 asoc = chunk->asoc; 113 if (msg->send_error) 114 error = msg->send_error; 115 else 116 error = asoc->outqueue.error; 117 118 sp = sctp_sk(asoc->base.sk); 119 notify = sctp_ulpevent_type_enabled(SCTP_SEND_FAILED, 120 &sp->subscribe); 121 } 122 123 /* Generate a SEND FAILED event only if enabled. */ 124 if (notify > 0) { 125 int sent; 126 if (chunk->has_tsn) 127 sent = SCTP_DATA_SENT; 128 else 129 sent = SCTP_DATA_UNSENT; 130 131 ev = sctp_ulpevent_make_send_failed(asoc, chunk, sent, 132 error, GFP_ATOMIC); 133 if (ev) 134 sctp_ulpq_tail_event(&asoc->ulpq, ev); 135 } 136 137 sctp_chunk_put(chunk); 138 } 139 140 SCTP_DBG_OBJCNT_DEC(datamsg); 141 kfree(msg); 142 } 143 144 /* Hold a reference. */ 145 static void sctp_datamsg_hold(struct sctp_datamsg *msg) 146 { 147 atomic_inc(&msg->refcnt); 148 } 149 150 /* Release a reference. */ 151 void sctp_datamsg_put(struct sctp_datamsg *msg) 152 { 153 if (atomic_dec_and_test(&msg->refcnt)) 154 sctp_datamsg_destroy(msg); 155 } 156 157 /* Assign a chunk to this datamsg. */ 158 static void sctp_datamsg_assign(struct sctp_datamsg *msg, struct sctp_chunk *chunk) 159 { 160 sctp_datamsg_hold(msg); 161 chunk->msg = msg; 162 } 163 164 165 /* A data chunk can have a maximum payload of (2^16 - 20). Break 166 * down any such message into smaller chunks. Opportunistically, fragment 167 * the chunks down to the current MTU constraints. We may get refragmented 168 * later if the PMTU changes, but it is _much better_ to fragment immediately 169 * with a reasonable guess than always doing our fragmentation on the 170 * soft-interrupt. 171 */ 172 struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc, 173 struct sctp_sndrcvinfo *sinfo, 174 struct msghdr *msgh, int msg_len) 175 { 176 int max, whole, i, offset, over, err; 177 int len, first_len; 178 int max_data; 179 struct sctp_chunk *chunk; 180 struct sctp_datamsg *msg; 181 struct list_head *pos, *temp; 182 __u8 frag; 183 184 msg = sctp_datamsg_new(GFP_KERNEL); 185 if (!msg) 186 return NULL; 187 188 /* Note: Calculate this outside of the loop, so that all fragments 189 * have the same expiration. 190 */ 191 if (sinfo->sinfo_timetolive) { 192 /* sinfo_timetolive is in milliseconds */ 193 msg->expires_at = jiffies + 194 msecs_to_jiffies(sinfo->sinfo_timetolive); 195 msg->can_abandon = 1; 196 SCTP_DEBUG_PRINTK("%s: msg:%p expires_at: %ld jiffies:%ld\n", 197 __func__, msg, msg->expires_at, jiffies); 198 } 199 200 /* This is the biggest possible DATA chunk that can fit into 201 * the packet 202 */ 203 max_data = asoc->pathmtu - 204 sctp_sk(asoc->base.sk)->pf->af->net_header_len - 205 sizeof(struct sctphdr) - sizeof(struct sctp_data_chunk); 206 207 max = asoc->frag_point; 208 /* If the the peer requested that we authenticate DATA chunks 209 * we need to accound for bundling of the AUTH chunks along with 210 * DATA. 211 */ 212 if (sctp_auth_send_cid(SCTP_CID_DATA, asoc)) { 213 struct sctp_hmac *hmac_desc = sctp_auth_asoc_get_hmac(asoc); 214 215 if (hmac_desc) 216 max_data -= WORD_ROUND(sizeof(sctp_auth_chunk_t) + 217 hmac_desc->hmac_len); 218 } 219 220 /* Now, check if we need to reduce our max */ 221 if (max > max_data) 222 max = max_data; 223 224 whole = 0; 225 first_len = max; 226 227 /* Check to see if we have a pending SACK and try to let it be bundled 228 * with this message. Do this if we don't have any data queued already. 229 * To check that, look at out_qlen and retransmit list. 230 * NOTE: we will not reduce to account for SACK, if the message would 231 * not have been fragmented. 232 */ 233 if (timer_pending(&asoc->timers[SCTP_EVENT_TIMEOUT_SACK]) && 234 asoc->outqueue.out_qlen == 0 && 235 list_empty(&asoc->outqueue.retransmit) && 236 msg_len > max) 237 max_data -= WORD_ROUND(sizeof(sctp_sack_chunk_t)); 238 239 /* Encourage Cookie-ECHO bundling. */ 240 if (asoc->state < SCTP_STATE_COOKIE_ECHOED) 241 max_data -= SCTP_ARBITRARY_COOKIE_ECHO_LEN; 242 243 /* Now that we adjusted completely, reset first_len */ 244 if (first_len > max_data) 245 first_len = max_data; 246 247 /* Account for a different sized first fragment */ 248 if (msg_len >= first_len) { 249 msg_len -= first_len; 250 whole = 1; 251 msg->can_delay = 0; 252 } 253 254 /* How many full sized? How many bytes leftover? */ 255 whole += msg_len / max; 256 over = msg_len % max; 257 offset = 0; 258 259 if ((whole > 1) || (whole && over)) 260 SCTP_INC_STATS_USER(SCTP_MIB_FRAGUSRMSGS); 261 262 /* Create chunks for all the full sized DATA chunks. */ 263 for (i=0, len=first_len; i < whole; i++) { 264 frag = SCTP_DATA_MIDDLE_FRAG; 265 266 if (0 == i) 267 frag |= SCTP_DATA_FIRST_FRAG; 268 269 if ((i == (whole - 1)) && !over) { 270 frag |= SCTP_DATA_LAST_FRAG; 271 272 /* The application requests to set the I-bit of the 273 * last DATA chunk of a user message when providing 274 * the user message to the SCTP implementation. 275 */ 276 if ((sinfo->sinfo_flags & SCTP_EOF) || 277 (sinfo->sinfo_flags & SCTP_SACK_IMMEDIATELY)) 278 frag |= SCTP_DATA_SACK_IMM; 279 } 280 281 chunk = sctp_make_datafrag_empty(asoc, sinfo, len, frag, 0); 282 283 if (!chunk) 284 goto errout; 285 err = sctp_user_addto_chunk(chunk, offset, len, msgh->msg_iov); 286 if (err < 0) 287 goto errout; 288 289 offset += len; 290 291 /* Put the chunk->skb back into the form expected by send. */ 292 __skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr 293 - (__u8 *)chunk->skb->data); 294 295 sctp_datamsg_assign(msg, chunk); 296 list_add_tail(&chunk->frag_list, &msg->chunks); 297 298 /* The first chunk, the first chunk was likely short 299 * to allow bundling, so reset to full size. 300 */ 301 if (0 == i) 302 len = max; 303 } 304 305 /* .. now the leftover bytes. */ 306 if (over) { 307 if (!whole) 308 frag = SCTP_DATA_NOT_FRAG; 309 else 310 frag = SCTP_DATA_LAST_FRAG; 311 312 if ((sinfo->sinfo_flags & SCTP_EOF) || 313 (sinfo->sinfo_flags & SCTP_SACK_IMMEDIATELY)) 314 frag |= SCTP_DATA_SACK_IMM; 315 316 chunk = sctp_make_datafrag_empty(asoc, sinfo, over, frag, 0); 317 318 if (!chunk) 319 goto errout; 320 321 err = sctp_user_addto_chunk(chunk, offset, over,msgh->msg_iov); 322 323 /* Put the chunk->skb back into the form expected by send. */ 324 __skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr 325 - (__u8 *)chunk->skb->data); 326 if (err < 0) 327 goto errout; 328 329 sctp_datamsg_assign(msg, chunk); 330 list_add_tail(&chunk->frag_list, &msg->chunks); 331 } 332 333 return msg; 334 335 errout: 336 list_for_each_safe(pos, temp, &msg->chunks) { 337 list_del_init(pos); 338 chunk = list_entry(pos, struct sctp_chunk, frag_list); 339 sctp_chunk_free(chunk); 340 } 341 sctp_datamsg_put(msg); 342 return NULL; 343 } 344 345 /* Check whether this message has expired. */ 346 int sctp_chunk_abandoned(struct sctp_chunk *chunk) 347 { 348 struct sctp_datamsg *msg = chunk->msg; 349 350 if (!msg->can_abandon) 351 return 0; 352 353 if (time_after(jiffies, msg->expires_at)) 354 return 1; 355 356 return 0; 357 } 358 359 /* This chunk (and consequently entire message) has failed in its sending. */ 360 void sctp_chunk_fail(struct sctp_chunk *chunk, int error) 361 { 362 chunk->msg->send_failed = 1; 363 chunk->msg->send_error = error; 364 } 365