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