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 } 63 64 /* Allocate and initialize datamsg. */ 65 SCTP_STATIC struct sctp_datamsg *sctp_datamsg_new(gfp_t gfp) 66 { 67 struct sctp_datamsg *msg; 68 msg = kmalloc(sizeof(struct sctp_datamsg), gfp); 69 if (msg) { 70 sctp_datamsg_init(msg); 71 SCTP_DBG_OBJCNT_INC(datamsg); 72 } 73 return msg; 74 } 75 76 /* Final destructruction of datamsg memory. */ 77 static void sctp_datamsg_destroy(struct sctp_datamsg *msg) 78 { 79 struct list_head *pos, *temp; 80 struct sctp_chunk *chunk; 81 struct sctp_sock *sp; 82 struct sctp_ulpevent *ev; 83 struct sctp_association *asoc = NULL; 84 int error = 0, notify; 85 86 /* If we failed, we may need to notify. */ 87 notify = msg->send_failed ? -1 : 0; 88 89 /* Release all references. */ 90 list_for_each_safe(pos, temp, &msg->chunks) { 91 list_del_init(pos); 92 chunk = list_entry(pos, struct sctp_chunk, frag_list); 93 /* Check whether we _really_ need to notify. */ 94 if (notify < 0) { 95 asoc = chunk->asoc; 96 if (msg->send_error) 97 error = msg->send_error; 98 else 99 error = asoc->outqueue.error; 100 101 sp = sctp_sk(asoc->base.sk); 102 notify = sctp_ulpevent_type_enabled(SCTP_SEND_FAILED, 103 &sp->subscribe); 104 } 105 106 /* Generate a SEND FAILED event only if enabled. */ 107 if (notify > 0) { 108 int sent; 109 if (chunk->has_tsn) 110 sent = SCTP_DATA_SENT; 111 else 112 sent = SCTP_DATA_UNSENT; 113 114 ev = sctp_ulpevent_make_send_failed(asoc, chunk, sent, 115 error, GFP_ATOMIC); 116 if (ev) 117 sctp_ulpq_tail_event(&asoc->ulpq, ev); 118 } 119 120 sctp_chunk_put(chunk); 121 } 122 123 SCTP_DBG_OBJCNT_DEC(datamsg); 124 kfree(msg); 125 } 126 127 /* Hold a reference. */ 128 static void sctp_datamsg_hold(struct sctp_datamsg *msg) 129 { 130 atomic_inc(&msg->refcnt); 131 } 132 133 /* Release a reference. */ 134 void sctp_datamsg_put(struct sctp_datamsg *msg) 135 { 136 if (atomic_dec_and_test(&msg->refcnt)) 137 sctp_datamsg_destroy(msg); 138 } 139 140 /* Assign a chunk to this datamsg. */ 141 static void sctp_datamsg_assign(struct sctp_datamsg *msg, struct sctp_chunk *chunk) 142 { 143 sctp_datamsg_hold(msg); 144 chunk->msg = msg; 145 } 146 147 148 /* A data chunk can have a maximum payload of (2^16 - 20). Break 149 * down any such message into smaller chunks. Opportunistically, fragment 150 * the chunks down to the current MTU constraints. We may get refragmented 151 * later if the PMTU changes, but it is _much better_ to fragment immediately 152 * with a reasonable guess than always doing our fragmentation on the 153 * soft-interrupt. 154 */ 155 struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc, 156 struct sctp_sndrcvinfo *sinfo, 157 struct msghdr *msgh, int msg_len) 158 { 159 int max, whole, i, offset, over, err; 160 int len, first_len; 161 struct sctp_chunk *chunk; 162 struct sctp_datamsg *msg; 163 struct list_head *pos, *temp; 164 __u8 frag; 165 166 msg = sctp_datamsg_new(GFP_KERNEL); 167 if (!msg) 168 return NULL; 169 170 /* Note: Calculate this outside of the loop, so that all fragments 171 * have the same expiration. 172 */ 173 if (sinfo->sinfo_timetolive) { 174 /* sinfo_timetolive is in milliseconds */ 175 msg->expires_at = jiffies + 176 msecs_to_jiffies(sinfo->sinfo_timetolive); 177 msg->can_abandon = 1; 178 SCTP_DEBUG_PRINTK("%s: msg:%p expires_at: %ld jiffies:%ld\n", 179 __func__, msg, msg->expires_at, jiffies); 180 } 181 182 max = asoc->frag_point; 183 184 /* If the the peer requested that we authenticate DATA chunks 185 * we need to accound for bundling of the AUTH chunks along with 186 * DATA. 187 */ 188 if (sctp_auth_send_cid(SCTP_CID_DATA, asoc)) { 189 struct sctp_hmac *hmac_desc = sctp_auth_asoc_get_hmac(asoc); 190 191 if (hmac_desc) 192 max -= WORD_ROUND(sizeof(sctp_auth_chunk_t) + 193 hmac_desc->hmac_len); 194 } 195 196 whole = 0; 197 first_len = max; 198 199 /* Encourage Cookie-ECHO bundling. */ 200 if (asoc->state < SCTP_STATE_COOKIE_ECHOED) { 201 whole = msg_len / (max - SCTP_ARBITRARY_COOKIE_ECHO_LEN); 202 203 /* Account for the DATA to be bundled with the COOKIE-ECHO. */ 204 if (whole) { 205 first_len = max - SCTP_ARBITRARY_COOKIE_ECHO_LEN; 206 msg_len -= first_len; 207 whole = 1; 208 } 209 } 210 211 /* How many full sized? How many bytes leftover? */ 212 whole += msg_len / max; 213 over = msg_len % max; 214 offset = 0; 215 216 if ((whole > 1) || (whole && over)) 217 SCTP_INC_STATS_USER(SCTP_MIB_FRAGUSRMSGS); 218 219 /* Create chunks for all the full sized DATA chunks. */ 220 for (i=0, len=first_len; i < whole; i++) { 221 frag = SCTP_DATA_MIDDLE_FRAG; 222 223 if (0 == i) 224 frag |= SCTP_DATA_FIRST_FRAG; 225 226 if ((i == (whole - 1)) && !over) 227 frag |= SCTP_DATA_LAST_FRAG; 228 229 chunk = sctp_make_datafrag_empty(asoc, sinfo, len, frag, 0); 230 231 if (!chunk) 232 goto errout; 233 err = sctp_user_addto_chunk(chunk, offset, len, msgh->msg_iov); 234 if (err < 0) 235 goto errout; 236 237 offset += len; 238 239 /* Put the chunk->skb back into the form expected by send. */ 240 __skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr 241 - (__u8 *)chunk->skb->data); 242 243 sctp_datamsg_assign(msg, chunk); 244 list_add_tail(&chunk->frag_list, &msg->chunks); 245 246 /* The first chunk, the first chunk was likely short 247 * to allow bundling, so reset to full size. 248 */ 249 if (0 == i) 250 len = max; 251 } 252 253 /* .. now the leftover bytes. */ 254 if (over) { 255 if (!whole) 256 frag = SCTP_DATA_NOT_FRAG; 257 else 258 frag = SCTP_DATA_LAST_FRAG; 259 260 chunk = sctp_make_datafrag_empty(asoc, sinfo, over, frag, 0); 261 262 if (!chunk) 263 goto errout; 264 265 err = sctp_user_addto_chunk(chunk, offset, over,msgh->msg_iov); 266 267 /* Put the chunk->skb back into the form expected by send. */ 268 __skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr 269 - (__u8 *)chunk->skb->data); 270 if (err < 0) 271 goto errout; 272 273 sctp_datamsg_assign(msg, chunk); 274 list_add_tail(&chunk->frag_list, &msg->chunks); 275 } 276 277 return msg; 278 279 errout: 280 list_for_each_safe(pos, temp, &msg->chunks) { 281 list_del_init(pos); 282 chunk = list_entry(pos, struct sctp_chunk, frag_list); 283 sctp_chunk_free(chunk); 284 } 285 sctp_datamsg_put(msg); 286 return NULL; 287 } 288 289 /* Check whether this message has expired. */ 290 int sctp_chunk_abandoned(struct sctp_chunk *chunk) 291 { 292 struct sctp_datamsg *msg = chunk->msg; 293 294 if (!msg->can_abandon) 295 return 0; 296 297 if (time_after(jiffies, msg->expires_at)) 298 return 1; 299 300 return 0; 301 } 302 303 /* This chunk (and consequently entire message) has failed in its sending. */ 304 void sctp_chunk_fail(struct sctp_chunk *chunk, int error) 305 { 306 chunk->msg->send_failed = 1; 307 chunk->msg->send_error = error; 308 } 309