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 atomic_set(&msg->refcnt, 1); 53 msg->send_failed = 0; 54 msg->send_error = 0; 55 msg->can_delay = 1; 56 msg->expires_at = 0; 57 INIT_LIST_HEAD(&msg->chunks); 58 } 59 60 /* Allocate and initialize datamsg. */ 61 static struct sctp_datamsg *sctp_datamsg_new(gfp_t gfp) 62 { 63 struct sctp_datamsg *msg; 64 msg = kmalloc(sizeof(struct sctp_datamsg), gfp); 65 if (msg) { 66 sctp_datamsg_init(msg); 67 SCTP_DBG_OBJCNT_INC(datamsg); 68 } 69 return msg; 70 } 71 72 void sctp_datamsg_free(struct sctp_datamsg *msg) 73 { 74 struct sctp_chunk *chunk; 75 76 /* This doesn't have to be a _safe vairant because 77 * sctp_chunk_free() only drops the refs. 78 */ 79 list_for_each_entry(chunk, &msg->chunks, frag_list) 80 sctp_chunk_free(chunk); 81 82 sctp_datamsg_put(msg); 83 } 84 85 /* Final destructruction of datamsg memory. */ 86 static void sctp_datamsg_destroy(struct sctp_datamsg *msg) 87 { 88 struct list_head *pos, *temp; 89 struct sctp_chunk *chunk; 90 struct sctp_sock *sp; 91 struct sctp_ulpevent *ev; 92 struct sctp_association *asoc = NULL; 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 sp = sctp_sk(asoc->base.sk); 111 notify = sctp_ulpevent_type_enabled(SCTP_SEND_FAILED, 112 &sp->subscribe); 113 } 114 115 /* Generate a SEND FAILED event only if enabled. */ 116 if (notify > 0) { 117 int sent; 118 if (chunk->has_tsn) 119 sent = SCTP_DATA_SENT; 120 else 121 sent = SCTP_DATA_UNSENT; 122 123 ev = sctp_ulpevent_make_send_failed(asoc, chunk, sent, 124 error, GFP_ATOMIC); 125 if (ev) 126 sctp_ulpq_tail_event(&asoc->ulpq, ev); 127 } 128 129 sctp_chunk_put(chunk); 130 } 131 132 SCTP_DBG_OBJCNT_DEC(datamsg); 133 kfree(msg); 134 } 135 136 /* Hold a reference. */ 137 static void sctp_datamsg_hold(struct sctp_datamsg *msg) 138 { 139 atomic_inc(&msg->refcnt); 140 } 141 142 /* Release a reference. */ 143 void sctp_datamsg_put(struct sctp_datamsg *msg) 144 { 145 if (atomic_dec_and_test(&msg->refcnt)) 146 sctp_datamsg_destroy(msg); 147 } 148 149 /* Assign a chunk to this datamsg. */ 150 static void sctp_datamsg_assign(struct sctp_datamsg *msg, struct sctp_chunk *chunk) 151 { 152 sctp_datamsg_hold(msg); 153 chunk->msg = msg; 154 } 155 156 157 /* A data chunk can have a maximum payload of (2^16 - 20). Break 158 * down any such message into smaller chunks. Opportunistically, fragment 159 * the chunks down to the current MTU constraints. We may get refragmented 160 * later if the PMTU changes, but it is _much better_ to fragment immediately 161 * with a reasonable guess than always doing our fragmentation on the 162 * soft-interrupt. 163 */ 164 struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc, 165 struct sctp_sndrcvinfo *sinfo, 166 struct iov_iter *from) 167 { 168 size_t len, first_len, max_data, remaining; 169 size_t msg_len = iov_iter_count(from); 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->pathmtu - 192 sctp_sk(asoc->base.sk)->pf->af->net_header_len - 193 sizeof(struct sctphdr) - sizeof(struct sctp_data_chunk); 194 max_data = SCTP_TRUNC4(max_data); 195 196 /* If the the peer requested that we authenticate DATA chunks 197 * we need to account for bundling of the AUTH chunks along with 198 * DATA. 199 */ 200 if (sctp_auth_send_cid(SCTP_CID_DATA, asoc)) { 201 struct sctp_hmac *hmac_desc = sctp_auth_asoc_get_hmac(asoc); 202 203 if (hmac_desc) 204 max_data -= SCTP_PAD4(sizeof(sctp_auth_chunk_t) + 205 hmac_desc->hmac_len); 206 } 207 208 /* Check what's our max considering the above */ 209 max_data = min_t(size_t, max_data, asoc->frag_point); 210 211 /* Set first_len and then account for possible bundles on first frag */ 212 first_len = max_data; 213 214 /* Check to see if we have a pending SACK and try to let it be bundled 215 * with this message. Do this if we don't have any data queued already. 216 * To check that, look at out_qlen and retransmit list. 217 * NOTE: we will not reduce to account for SACK, if the message would 218 * not have been fragmented. 219 */ 220 if (timer_pending(&asoc->timers[SCTP_EVENT_TIMEOUT_SACK]) && 221 asoc->outqueue.out_qlen == 0 && 222 list_empty(&asoc->outqueue.retransmit) && 223 msg_len > max_data) 224 first_len -= SCTP_PAD4(sizeof(sctp_sack_chunk_t)); 225 226 /* Encourage Cookie-ECHO bundling. */ 227 if (asoc->state < SCTP_STATE_COOKIE_ECHOED) 228 first_len -= SCTP_ARBITRARY_COOKIE_ECHO_LEN; 229 230 /* Account for a different sized first fragment */ 231 if (msg_len >= first_len) { 232 msg->can_delay = 0; 233 SCTP_INC_STATS(sock_net(asoc->base.sk), SCTP_MIB_FRAGUSRMSGS); 234 } else { 235 /* Which may be the only one... */ 236 first_len = msg_len; 237 } 238 239 /* Create chunks for all DATA chunks. */ 240 for (remaining = msg_len; remaining; remaining -= len) { 241 u8 frag = SCTP_DATA_MIDDLE_FRAG; 242 243 if (remaining == msg_len) { 244 /* First frag, which may also be the last */ 245 frag |= SCTP_DATA_FIRST_FRAG; 246 len = first_len; 247 } else { 248 /* Middle frags */ 249 len = max_data; 250 } 251 252 if (len >= remaining) { 253 /* Last frag, which may also be the first */ 254 len = remaining; 255 frag |= SCTP_DATA_LAST_FRAG; 256 257 /* The application requests to set the I-bit of the 258 * last DATA chunk of a user message when providing 259 * the user message to the SCTP implementation. 260 */ 261 if ((sinfo->sinfo_flags & SCTP_EOF) || 262 (sinfo->sinfo_flags & SCTP_SACK_IMMEDIATELY)) 263 frag |= SCTP_DATA_SACK_IMM; 264 } 265 266 chunk = sctp_make_datafrag_empty(asoc, sinfo, len, frag, 267 0, GFP_KERNEL); 268 if (!chunk) { 269 err = -ENOMEM; 270 goto errout; 271 } 272 273 err = sctp_user_addto_chunk(chunk, len, from); 274 if (err < 0) 275 goto errout_chunk_free; 276 277 /* Put the chunk->skb back into the form expected by send. */ 278 __skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr - 279 chunk->skb->data); 280 281 sctp_datamsg_assign(msg, chunk); 282 list_add_tail(&chunk->frag_list, &msg->chunks); 283 } 284 285 return msg; 286 287 errout_chunk_free: 288 sctp_chunk_free(chunk); 289 290 errout: 291 list_for_each_safe(pos, temp, &msg->chunks) { 292 list_del_init(pos); 293 chunk = list_entry(pos, struct sctp_chunk, frag_list); 294 sctp_chunk_free(chunk); 295 } 296 sctp_datamsg_put(msg); 297 298 return ERR_PTR(err); 299 } 300 301 /* Check whether this message has expired. */ 302 int sctp_chunk_abandoned(struct sctp_chunk *chunk) 303 { 304 if (!chunk->asoc->peer.prsctp_capable) 305 return 0; 306 307 if (SCTP_PR_TTL_ENABLED(chunk->sinfo.sinfo_flags) && 308 time_after(jiffies, chunk->msg->expires_at)) { 309 struct sctp_stream_out *streamout = 310 &chunk->asoc->stream->out[chunk->sinfo.sinfo_stream]; 311 312 if (chunk->sent_count) { 313 chunk->asoc->abandoned_sent[SCTP_PR_INDEX(TTL)]++; 314 streamout->abandoned_sent[SCTP_PR_INDEX(TTL)]++; 315 } else { 316 chunk->asoc->abandoned_unsent[SCTP_PR_INDEX(TTL)]++; 317 streamout->abandoned_unsent[SCTP_PR_INDEX(TTL)]++; 318 } 319 return 1; 320 } else if (SCTP_PR_RTX_ENABLED(chunk->sinfo.sinfo_flags) && 321 chunk->sent_count > chunk->sinfo.sinfo_timetolive) { 322 struct sctp_stream_out *streamout = 323 &chunk->asoc->stream->out[chunk->sinfo.sinfo_stream]; 324 325 chunk->asoc->abandoned_sent[SCTP_PR_INDEX(RTX)]++; 326 streamout->abandoned_sent[SCTP_PR_INDEX(RTX)]++; 327 return 1; 328 } else if (!SCTP_PR_POLICY(chunk->sinfo.sinfo_flags) && 329 chunk->msg->expires_at && 330 time_after(jiffies, chunk->msg->expires_at)) { 331 return 1; 332 } 333 /* PRIO policy is processed by sendmsg, not here */ 334 335 return 0; 336 } 337 338 /* This chunk (and consequently entire message) has failed in its sending. */ 339 void sctp_chunk_fail(struct sctp_chunk *chunk, int error) 340 { 341 chunk->msg->send_failed = 1; 342 chunk->msg->send_error = error; 343 } 344