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, see 22 * <http://www.gnu.org/licenses/>. 23 * 24 * Please send any bug reports or fixes you make to the 25 * email address(es): 26 * lksctp developers <linux-sctp@vger.kernel.org> 27 * 28 * Written or modified by: 29 * Jon Grimm <jgrimm@us.ibm.com> 30 * Sridhar Samudrala <sri@us.ibm.com> 31 */ 32 33 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 34 35 #include <linux/types.h> 36 #include <linux/kernel.h> 37 #include <linux/net.h> 38 #include <linux/inet.h> 39 #include <linux/skbuff.h> 40 #include <linux/slab.h> 41 #include <net/sock.h> 42 #include <net/sctp/sctp.h> 43 #include <net/sctp/sm.h> 44 45 /* This file is mostly in anticipation of future work, but initially 46 * populate with fragment tracking for an outbound message. 47 */ 48 49 /* Initialize datamsg from memory. */ 50 static void sctp_datamsg_init(struct sctp_datamsg *msg) 51 { 52 refcount_set(&msg->refcnt, 1); 53 msg->send_failed = 0; 54 msg->send_error = 0; 55 msg->can_delay = 1; 56 msg->abandoned = 0; 57 msg->expires_at = 0; 58 INIT_LIST_HEAD(&msg->chunks); 59 } 60 61 /* Allocate and initialize datamsg. */ 62 static struct sctp_datamsg *sctp_datamsg_new(gfp_t gfp) 63 { 64 struct sctp_datamsg *msg; 65 msg = kmalloc(sizeof(struct sctp_datamsg), gfp); 66 if (msg) { 67 sctp_datamsg_init(msg); 68 SCTP_DBG_OBJCNT_INC(datamsg); 69 } 70 return msg; 71 } 72 73 void sctp_datamsg_free(struct sctp_datamsg *msg) 74 { 75 struct sctp_chunk *chunk; 76 77 /* This doesn't have to be a _safe vairant because 78 * sctp_chunk_free() only drops the refs. 79 */ 80 list_for_each_entry(chunk, &msg->chunks, frag_list) 81 sctp_chunk_free(chunk); 82 83 sctp_datamsg_put(msg); 84 } 85 86 /* Final destructruction of datamsg memory. */ 87 static void sctp_datamsg_destroy(struct sctp_datamsg *msg) 88 { 89 struct sctp_association *asoc = NULL; 90 struct list_head *pos, *temp; 91 struct sctp_chunk *chunk; 92 struct sctp_ulpevent *ev; 93 int error = 0, notify; 94 95 /* If we failed, we may need to notify. */ 96 notify = msg->send_failed ? -1 : 0; 97 98 /* Release all references. */ 99 list_for_each_safe(pos, temp, &msg->chunks) { 100 list_del_init(pos); 101 chunk = list_entry(pos, struct sctp_chunk, frag_list); 102 /* Check whether we _really_ need to notify. */ 103 if (notify < 0) { 104 asoc = chunk->asoc; 105 if (msg->send_error) 106 error = msg->send_error; 107 else 108 error = asoc->outqueue.error; 109 110 notify = sctp_ulpevent_type_enabled(asoc->subscribe, 111 SCTP_SEND_FAILED); 112 } 113 114 /* Generate a SEND FAILED event only if enabled. */ 115 if (notify > 0) { 116 int sent; 117 if (chunk->has_tsn) 118 sent = SCTP_DATA_SENT; 119 else 120 sent = SCTP_DATA_UNSENT; 121 122 ev = sctp_ulpevent_make_send_failed(asoc, chunk, sent, 123 error, GFP_ATOMIC); 124 if (ev) 125 asoc->stream.si->enqueue_event(&asoc->ulpq, ev); 126 } 127 128 sctp_chunk_put(chunk); 129 } 130 131 SCTP_DBG_OBJCNT_DEC(datamsg); 132 kfree(msg); 133 } 134 135 /* Hold a reference. */ 136 static void sctp_datamsg_hold(struct sctp_datamsg *msg) 137 { 138 refcount_inc(&msg->refcnt); 139 } 140 141 /* Release a reference. */ 142 void sctp_datamsg_put(struct sctp_datamsg *msg) 143 { 144 if (refcount_dec_and_test(&msg->refcnt)) 145 sctp_datamsg_destroy(msg); 146 } 147 148 /* Assign a chunk to this datamsg. */ 149 static void sctp_datamsg_assign(struct sctp_datamsg *msg, struct sctp_chunk *chunk) 150 { 151 sctp_datamsg_hold(msg); 152 chunk->msg = msg; 153 } 154 155 156 /* A data chunk can have a maximum payload of (2^16 - 20). Break 157 * down any such message into smaller chunks. Opportunistically, fragment 158 * the chunks down to the current MTU constraints. We may get refragmented 159 * later if the PMTU changes, but it is _much better_ to fragment immediately 160 * with a reasonable guess than always doing our fragmentation on the 161 * soft-interrupt. 162 */ 163 struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc, 164 struct sctp_sndrcvinfo *sinfo, 165 struct iov_iter *from) 166 { 167 size_t len, first_len, max_data, remaining; 168 size_t msg_len = iov_iter_count(from); 169 struct sctp_shared_key *shkey = NULL; 170 struct list_head *pos, *temp; 171 struct sctp_chunk *chunk; 172 struct sctp_datamsg *msg; 173 int err; 174 175 msg = sctp_datamsg_new(GFP_KERNEL); 176 if (!msg) 177 return ERR_PTR(-ENOMEM); 178 179 /* Note: Calculate this outside of the loop, so that all fragments 180 * have the same expiration. 181 */ 182 if (asoc->peer.prsctp_capable && sinfo->sinfo_timetolive && 183 (SCTP_PR_TTL_ENABLED(sinfo->sinfo_flags) || 184 !SCTP_PR_POLICY(sinfo->sinfo_flags))) 185 msg->expires_at = jiffies + 186 msecs_to_jiffies(sinfo->sinfo_timetolive); 187 188 /* This is the biggest possible DATA chunk that can fit into 189 * the packet 190 */ 191 max_data = asoc->frag_point; 192 if (unlikely(!max_data)) { 193 max_data = sctp_min_frag_point(sctp_sk(asoc->base.sk), 194 sctp_datachk_len(&asoc->stream)); 195 pr_warn_ratelimited("%s: asoc:%p frag_point is zero, forcing max_data to default minimum (%zu)", 196 __func__, asoc, max_data); 197 } 198 199 /* If the the peer requested that we authenticate DATA chunks 200 * we need to account for bundling of the AUTH chunks along with 201 * DATA. 202 */ 203 if (sctp_auth_send_cid(SCTP_CID_DATA, asoc)) { 204 struct sctp_hmac *hmac_desc = sctp_auth_asoc_get_hmac(asoc); 205 206 if (hmac_desc) 207 max_data -= SCTP_PAD4(sizeof(struct sctp_auth_chunk) + 208 hmac_desc->hmac_len); 209 210 if (sinfo->sinfo_tsn && 211 sinfo->sinfo_ssn != asoc->active_key_id) { 212 shkey = sctp_auth_get_shkey(asoc, sinfo->sinfo_ssn); 213 if (!shkey) { 214 err = -EINVAL; 215 goto errout; 216 } 217 } else { 218 shkey = asoc->shkey; 219 } 220 } 221 222 /* Set first_len and then account for possible bundles on first frag */ 223 first_len = max_data; 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_data) 235 first_len -= SCTP_PAD4(sizeof(struct sctp_sack_chunk)); 236 237 /* Encourage Cookie-ECHO bundling. */ 238 if (asoc->state < SCTP_STATE_COOKIE_ECHOED) 239 first_len -= SCTP_ARBITRARY_COOKIE_ECHO_LEN; 240 241 /* Account for a different sized first fragment */ 242 if (msg_len >= first_len) { 243 msg->can_delay = 0; 244 if (msg_len > first_len) 245 SCTP_INC_STATS(sock_net(asoc->base.sk), 246 SCTP_MIB_FRAGUSRMSGS); 247 } else { 248 /* Which may be the only one... */ 249 first_len = msg_len; 250 } 251 252 /* Create chunks for all DATA chunks. */ 253 for (remaining = msg_len; remaining; remaining -= len) { 254 u8 frag = SCTP_DATA_MIDDLE_FRAG; 255 256 if (remaining == msg_len) { 257 /* First frag, which may also be the last */ 258 frag |= SCTP_DATA_FIRST_FRAG; 259 len = first_len; 260 } else { 261 /* Middle frags */ 262 len = max_data; 263 } 264 265 if (len >= remaining) { 266 /* Last frag, which may also be the first */ 267 len = remaining; 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 = asoc->stream.si->make_datafrag(asoc, sinfo, len, frag, 280 GFP_KERNEL); 281 if (!chunk) { 282 err = -ENOMEM; 283 goto errout; 284 } 285 286 err = sctp_user_addto_chunk(chunk, len, from); 287 if (err < 0) 288 goto errout_chunk_free; 289 290 chunk->shkey = shkey; 291 292 /* Put the chunk->skb back into the form expected by send. */ 293 __skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr - 294 chunk->skb->data); 295 296 sctp_datamsg_assign(msg, chunk); 297 list_add_tail(&chunk->frag_list, &msg->chunks); 298 } 299 300 return msg; 301 302 errout_chunk_free: 303 sctp_chunk_free(chunk); 304 305 errout: 306 list_for_each_safe(pos, temp, &msg->chunks) { 307 list_del_init(pos); 308 chunk = list_entry(pos, struct sctp_chunk, frag_list); 309 sctp_chunk_free(chunk); 310 } 311 sctp_datamsg_put(msg); 312 313 return ERR_PTR(err); 314 } 315 316 /* Check whether this message has expired. */ 317 int sctp_chunk_abandoned(struct sctp_chunk *chunk) 318 { 319 if (!chunk->asoc->peer.prsctp_capable) 320 return 0; 321 322 if (chunk->msg->abandoned) 323 return 1; 324 325 if (!chunk->has_tsn && 326 !(chunk->chunk_hdr->flags & SCTP_DATA_FIRST_FRAG)) 327 return 0; 328 329 if (SCTP_PR_TTL_ENABLED(chunk->sinfo.sinfo_flags) && 330 time_after(jiffies, chunk->msg->expires_at)) { 331 struct sctp_stream_out *streamout = 332 SCTP_SO(&chunk->asoc->stream, 333 chunk->sinfo.sinfo_stream); 334 335 if (chunk->sent_count) { 336 chunk->asoc->abandoned_sent[SCTP_PR_INDEX(TTL)]++; 337 streamout->ext->abandoned_sent[SCTP_PR_INDEX(TTL)]++; 338 } else { 339 chunk->asoc->abandoned_unsent[SCTP_PR_INDEX(TTL)]++; 340 streamout->ext->abandoned_unsent[SCTP_PR_INDEX(TTL)]++; 341 } 342 chunk->msg->abandoned = 1; 343 return 1; 344 } else if (SCTP_PR_RTX_ENABLED(chunk->sinfo.sinfo_flags) && 345 chunk->sent_count > chunk->sinfo.sinfo_timetolive) { 346 struct sctp_stream_out *streamout = 347 SCTP_SO(&chunk->asoc->stream, 348 chunk->sinfo.sinfo_stream); 349 350 chunk->asoc->abandoned_sent[SCTP_PR_INDEX(RTX)]++; 351 streamout->ext->abandoned_sent[SCTP_PR_INDEX(RTX)]++; 352 chunk->msg->abandoned = 1; 353 return 1; 354 } else if (!SCTP_PR_POLICY(chunk->sinfo.sinfo_flags) && 355 chunk->msg->expires_at && 356 time_after(jiffies, chunk->msg->expires_at)) { 357 chunk->msg->abandoned = 1; 358 return 1; 359 } 360 /* PRIO policy is processed by sendmsg, not here */ 361 362 return 0; 363 } 364 365 /* This chunk (and consequently entire message) has failed in its sending. */ 366 void sctp_chunk_fail(struct sctp_chunk *chunk, int error) 367 { 368 chunk->msg->send_failed = 1; 369 chunk->msg->send_error = error; 370 } 371