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 list_head *pos, *temp; 90 struct sctp_chunk *chunk; 91 struct sctp_sock *sp; 92 struct sctp_ulpevent *ev; 93 struct sctp_association *asoc = NULL; 94 int error = 0, notify; 95 96 /* If we failed, we may need to notify. */ 97 notify = msg->send_failed ? -1 : 0; 98 99 /* Release all references. */ 100 list_for_each_safe(pos, temp, &msg->chunks) { 101 list_del_init(pos); 102 chunk = list_entry(pos, struct sctp_chunk, frag_list); 103 /* Check whether we _really_ need to notify. */ 104 if (notify < 0) { 105 asoc = chunk->asoc; 106 if (msg->send_error) 107 error = msg->send_error; 108 else 109 error = asoc->outqueue.error; 110 111 sp = sctp_sk(asoc->base.sk); 112 notify = sctp_ulpevent_type_enabled(SCTP_SEND_FAILED, 113 &sp->subscribe); 114 } 115 116 /* Generate a SEND FAILED event only if enabled. */ 117 if (notify > 0) { 118 int sent; 119 if (chunk->has_tsn) 120 sent = SCTP_DATA_SENT; 121 else 122 sent = SCTP_DATA_UNSENT; 123 124 ev = sctp_ulpevent_make_send_failed(asoc, chunk, sent, 125 error, GFP_ATOMIC); 126 if (ev) 127 asoc->stream.si->enqueue_event(&asoc->ulpq, ev); 128 } 129 130 sctp_chunk_put(chunk); 131 } 132 133 SCTP_DBG_OBJCNT_DEC(datamsg); 134 kfree(msg); 135 } 136 137 /* Hold a reference. */ 138 static void sctp_datamsg_hold(struct sctp_datamsg *msg) 139 { 140 refcount_inc(&msg->refcnt); 141 } 142 143 /* Release a reference. */ 144 void sctp_datamsg_put(struct sctp_datamsg *msg) 145 { 146 if (refcount_dec_and_test(&msg->refcnt)) 147 sctp_datamsg_destroy(msg); 148 } 149 150 /* Assign a chunk to this datamsg. */ 151 static void sctp_datamsg_assign(struct sctp_datamsg *msg, struct sctp_chunk *chunk) 152 { 153 sctp_datamsg_hold(msg); 154 chunk->msg = msg; 155 } 156 157 158 /* A data chunk can have a maximum payload of (2^16 - 20). Break 159 * down any such message into smaller chunks. Opportunistically, fragment 160 * the chunks down to the current MTU constraints. We may get refragmented 161 * later if the PMTU changes, but it is _much better_ to fragment immediately 162 * with a reasonable guess than always doing our fragmentation on the 163 * soft-interrupt. 164 */ 165 struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc, 166 struct sctp_sndrcvinfo *sinfo, 167 struct iov_iter *from) 168 { 169 size_t len, first_len, max_data, remaining; 170 size_t msg_len = iov_iter_count(from); 171 struct sctp_shared_key *shkey = NULL; 172 struct list_head *pos, *temp; 173 struct sctp_chunk *chunk; 174 struct sctp_datamsg *msg; 175 struct sctp_sock *sp; 176 struct sctp_af *af; 177 int err; 178 179 msg = sctp_datamsg_new(GFP_KERNEL); 180 if (!msg) 181 return ERR_PTR(-ENOMEM); 182 183 /* Note: Calculate this outside of the loop, so that all fragments 184 * have the same expiration. 185 */ 186 if (asoc->peer.prsctp_capable && sinfo->sinfo_timetolive && 187 (SCTP_PR_TTL_ENABLED(sinfo->sinfo_flags) || 188 !SCTP_PR_POLICY(sinfo->sinfo_flags))) 189 msg->expires_at = jiffies + 190 msecs_to_jiffies(sinfo->sinfo_timetolive); 191 192 /* This is the biggest possible DATA chunk that can fit into 193 * the packet 194 */ 195 sp = sctp_sk(asoc->base.sk); 196 af = sp->pf->af; 197 max_data = asoc->pathmtu - af->net_header_len - 198 sizeof(struct sctphdr) - sctp_datachk_len(&asoc->stream) - 199 af->ip_options_len(asoc->base.sk); 200 max_data = SCTP_TRUNC4(max_data); 201 202 /* If the the peer requested that we authenticate DATA chunks 203 * we need to account for bundling of the AUTH chunks along with 204 * DATA. 205 */ 206 if (sctp_auth_send_cid(SCTP_CID_DATA, asoc)) { 207 struct sctp_hmac *hmac_desc = sctp_auth_asoc_get_hmac(asoc); 208 209 if (hmac_desc) 210 max_data -= SCTP_PAD4(sizeof(struct sctp_auth_chunk) + 211 hmac_desc->hmac_len); 212 213 if (sinfo->sinfo_tsn && 214 sinfo->sinfo_ssn != asoc->active_key_id) { 215 shkey = sctp_auth_get_shkey(asoc, sinfo->sinfo_ssn); 216 if (!shkey) { 217 err = -EINVAL; 218 goto errout; 219 } 220 } else { 221 shkey = asoc->shkey; 222 } 223 } 224 225 /* Check what's our max considering the above */ 226 max_data = min_t(size_t, max_data, asoc->frag_point); 227 228 /* Set first_len and then account for possible bundles on first frag */ 229 first_len = max_data; 230 231 /* Check to see if we have a pending SACK and try to let it be bundled 232 * with this message. Do this if we don't have any data queued already. 233 * To check that, look at out_qlen and retransmit list. 234 * NOTE: we will not reduce to account for SACK, if the message would 235 * not have been fragmented. 236 */ 237 if (timer_pending(&asoc->timers[SCTP_EVENT_TIMEOUT_SACK]) && 238 asoc->outqueue.out_qlen == 0 && 239 list_empty(&asoc->outqueue.retransmit) && 240 msg_len > max_data) 241 first_len -= SCTP_PAD4(sizeof(struct sctp_sack_chunk)); 242 243 /* Encourage Cookie-ECHO bundling. */ 244 if (asoc->state < SCTP_STATE_COOKIE_ECHOED) 245 first_len -= SCTP_ARBITRARY_COOKIE_ECHO_LEN; 246 247 /* Account for a different sized first fragment */ 248 if (msg_len >= first_len) { 249 msg->can_delay = 0; 250 SCTP_INC_STATS(sock_net(asoc->base.sk), SCTP_MIB_FRAGUSRMSGS); 251 } else { 252 /* Which may be the only one... */ 253 first_len = msg_len; 254 } 255 256 /* Create chunks for all DATA chunks. */ 257 for (remaining = msg_len; remaining; remaining -= len) { 258 u8 frag = SCTP_DATA_MIDDLE_FRAG; 259 260 if (remaining == msg_len) { 261 /* First frag, which may also be the last */ 262 frag |= SCTP_DATA_FIRST_FRAG; 263 len = first_len; 264 } else { 265 /* Middle frags */ 266 len = max_data; 267 } 268 269 if (len >= remaining) { 270 /* Last frag, which may also be the first */ 271 len = remaining; 272 frag |= SCTP_DATA_LAST_FRAG; 273 274 /* The application requests to set the I-bit of the 275 * last DATA chunk of a user message when providing 276 * the user message to the SCTP implementation. 277 */ 278 if ((sinfo->sinfo_flags & SCTP_EOF) || 279 (sinfo->sinfo_flags & SCTP_SACK_IMMEDIATELY)) 280 frag |= SCTP_DATA_SACK_IMM; 281 } 282 283 chunk = asoc->stream.si->make_datafrag(asoc, sinfo, len, frag, 284 GFP_KERNEL); 285 if (!chunk) { 286 err = -ENOMEM; 287 goto errout; 288 } 289 290 err = sctp_user_addto_chunk(chunk, len, from); 291 if (err < 0) 292 goto errout_chunk_free; 293 294 chunk->shkey = shkey; 295 296 /* Put the chunk->skb back into the form expected by send. */ 297 __skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr - 298 chunk->skb->data); 299 300 sctp_datamsg_assign(msg, chunk); 301 list_add_tail(&chunk->frag_list, &msg->chunks); 302 } 303 304 return msg; 305 306 errout_chunk_free: 307 sctp_chunk_free(chunk); 308 309 errout: 310 list_for_each_safe(pos, temp, &msg->chunks) { 311 list_del_init(pos); 312 chunk = list_entry(pos, struct sctp_chunk, frag_list); 313 sctp_chunk_free(chunk); 314 } 315 sctp_datamsg_put(msg); 316 317 return ERR_PTR(err); 318 } 319 320 /* Check whether this message has expired. */ 321 int sctp_chunk_abandoned(struct sctp_chunk *chunk) 322 { 323 if (!chunk->asoc->peer.prsctp_capable) 324 return 0; 325 326 if (chunk->msg->abandoned) 327 return 1; 328 329 if (!chunk->has_tsn && 330 !(chunk->chunk_hdr->flags & SCTP_DATA_FIRST_FRAG)) 331 return 0; 332 333 if (SCTP_PR_TTL_ENABLED(chunk->sinfo.sinfo_flags) && 334 time_after(jiffies, chunk->msg->expires_at)) { 335 struct sctp_stream_out *streamout = 336 &chunk->asoc->stream.out[chunk->sinfo.sinfo_stream]; 337 338 if (chunk->sent_count) { 339 chunk->asoc->abandoned_sent[SCTP_PR_INDEX(TTL)]++; 340 streamout->ext->abandoned_sent[SCTP_PR_INDEX(TTL)]++; 341 } else { 342 chunk->asoc->abandoned_unsent[SCTP_PR_INDEX(TTL)]++; 343 streamout->ext->abandoned_unsent[SCTP_PR_INDEX(TTL)]++; 344 } 345 chunk->msg->abandoned = 1; 346 return 1; 347 } else if (SCTP_PR_RTX_ENABLED(chunk->sinfo.sinfo_flags) && 348 chunk->sent_count > chunk->sinfo.sinfo_timetolive) { 349 struct sctp_stream_out *streamout = 350 &chunk->asoc->stream.out[chunk->sinfo.sinfo_stream]; 351 352 chunk->asoc->abandoned_sent[SCTP_PR_INDEX(RTX)]++; 353 streamout->ext->abandoned_sent[SCTP_PR_INDEX(RTX)]++; 354 chunk->msg->abandoned = 1; 355 return 1; 356 } else if (!SCTP_PR_POLICY(chunk->sinfo.sinfo_flags) && 357 chunk->msg->expires_at && 358 time_after(jiffies, chunk->msg->expires_at)) { 359 chunk->msg->abandoned = 1; 360 return 1; 361 } 362 /* PRIO policy is processed by sendmsg, not here */ 363 364 return 0; 365 } 366 367 /* This chunk (and consequently entire message) has failed in its sending. */ 368 void sctp_chunk_fail(struct sctp_chunk *chunk, int error) 369 { 370 chunk->msg->send_failed = 1; 371 chunk->msg->send_error = error; 372 } 373