1/* SCTP kernel reference Implementation 2 * (C) Copyright IBM Corp. 2003, 2004 3 * 4 * This file is part of the SCTP kernel reference Implementation 5 * 6 * This file contains the code relating the chunk abstraction. 7 * 8 * The SCTP reference 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 * The SCTP reference 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. */ 54static 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. */ 65SCTP_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 return msg; 73} 74 75/* Final destructruction of datamsg memory. */ 76static void sctp_datamsg_destroy(struct sctp_datamsg *msg) 77{ 78 struct list_head *pos, *temp; 79 struct sctp_chunk *chunk; 80 struct sctp_sock *sp; 81 struct sctp_ulpevent *ev; 82 struct sctp_association *asoc = NULL; 83 int error = 0, notify; 84 85 /* If we failed, we may need to notify. */ 86 notify = msg->send_failed ? -1 : 0; 87 88 /* Release all references. */ 89 list_for_each_safe(pos, temp, &msg->chunks) { 90 list_del_init(pos); 91 chunk = list_entry(pos, struct sctp_chunk, frag_list); 92 /* Check whether we _really_ need to notify. */ 93 if (notify < 0) { 94 asoc = chunk->asoc; 95 if (msg->send_error) 96 error = msg->send_error; 97 else 98 error = asoc->outqueue.error; 99 100 sp = sctp_sk(asoc->base.sk); 101 notify = sctp_ulpevent_type_enabled(SCTP_SEND_FAILED, 102 &sp->subscribe); 103 } 104 105 /* Generate a SEND FAILED event only if enabled. */ 106 if (notify > 0) { 107 int sent; 108 if (chunk->has_tsn) 109 sent = SCTP_DATA_SENT; 110 else 111 sent = SCTP_DATA_UNSENT; 112 113 ev = sctp_ulpevent_make_send_failed(asoc, chunk, sent, 114 error, GFP_ATOMIC); 115 if (ev) 116 sctp_ulpq_tail_event(&asoc->ulpq, ev); 117 } 118 119 sctp_chunk_put(chunk); 120 } 121 122 SCTP_DBG_OBJCNT_DEC(datamsg); 123 kfree(msg); 124} 125 126/* Hold a reference. */ 127static void sctp_datamsg_hold(struct sctp_datamsg *msg) 128{ 129 atomic_inc(&msg->refcnt); 130} 131 132/* Release a reference. */ 133void sctp_datamsg_put(struct sctp_datamsg *msg) 134{ 135 if (atomic_dec_and_test(&msg->refcnt)) 136 sctp_datamsg_destroy(msg); 137} 138 139/* Free a message. Really just give up a reference, the 140 * really free happens in sctp_datamsg_destroy(). 141 */ 142void sctp_datamsg_free(struct sctp_datamsg *msg) 143{ 144 sctp_datamsg_put(msg); 145} 146 147/* Hold on to all the fragments until all chunks have been sent. */ 148void sctp_datamsg_track(struct sctp_chunk *chunk) 149{ 150 sctp_chunk_hold(chunk); 151} 152 153/* Assign a chunk to this datamsg. */ 154static void sctp_datamsg_assign(struct sctp_datamsg *msg, struct sctp_chunk *chunk) 155{ 156 sctp_datamsg_hold(msg); 157 chunk->msg = msg; 158} 159 160 161/* A data chunk can have a maximum payload of (2^16 - 20). Break 162 * down any such message into smaller chunks. Opportunistically, fragment 163 * the chunks down to the current MTU constraints. We may get refragmented 164 * later if the PMTU changes, but it is _much better_ to fragment immediately 165 * with a reasonable guess than always doing our fragmentation on the 166 * soft-interrupt. 167 */ 168struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc, 169 struct sctp_sndrcvinfo *sinfo, 170 struct msghdr *msgh, int msg_len) 171{ 172 int max, whole, i, offset, over, err; 173 int len, first_len; 174 struct sctp_chunk *chunk; 175 struct sctp_datamsg *msg; 176 struct list_head *pos, *temp; 177 __u8 frag; 178 179 msg = sctp_datamsg_new(GFP_KERNEL); 180 if (!msg) 181 return NULL; 182 183 /* Note: Calculate this outside of the loop, so that all fragments 184 * have the same expiration. 185 */ 186 if (sinfo->sinfo_timetolive) { 187 /* sinfo_timetolive is in milliseconds */ 188 msg->expires_at = jiffies + 189 msecs_to_jiffies(sinfo->sinfo_timetolive); 190 msg->can_abandon = 1; 191 SCTP_DEBUG_PRINTK("%s: msg:%p expires_at: %ld jiffies:%ld\n", 192 __FUNCTION__, msg, msg->expires_at, jiffies); 193 } 194 195 max = asoc->frag_point; 196 197 whole = 0; 198 first_len = max; 199 200 /* Encourage Cookie-ECHO bundling. */ 201 if (asoc->state < SCTP_STATE_COOKIE_ECHOED) { 202 whole = msg_len / (max - SCTP_ARBITRARY_COOKIE_ECHO_LEN); 203 204 /* Account for the DATA to be bundled with the COOKIE-ECHO. */ 205 if (whole) { 206 first_len = max - SCTP_ARBITRARY_COOKIE_ECHO_LEN; 207 msg_len -= first_len; 208 whole = 1; 209 } 210 } 211 212 /* How many full sized? How many bytes leftover? */ 213 whole += msg_len / max; 214 over = msg_len % max; 215 offset = 0; 216 217 if ((whole > 1) || (whole && over)) 218 SCTP_INC_STATS_USER(SCTP_MIB_FRAGUSRMSGS); 219 220 /* Create chunks for all the full sized DATA chunks. */ 221 for (i=0, len=first_len; i < whole; i++) { 222 frag = SCTP_DATA_MIDDLE_FRAG; 223 224 if (0 == i) 225 frag |= SCTP_DATA_FIRST_FRAG; 226 227 if ((i == (whole - 1)) && !over) 228 frag |= SCTP_DATA_LAST_FRAG; 229 230 chunk = sctp_make_datafrag_empty(asoc, sinfo, len, frag, 0); 231 232 if (!chunk) 233 goto errout; 234 err = sctp_user_addto_chunk(chunk, offset, len, msgh->msg_iov); 235 if (err < 0) 236 goto errout; 237 238 offset += len; 239 240 /* Put the chunk->skb back into the form expected by send. */ 241 __skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr 242 - (__u8 *)chunk->skb->data); 243 244 sctp_datamsg_assign(msg, chunk); 245 list_add_tail(&chunk->frag_list, &msg->chunks); 246 247 /* The first chunk, the first chunk was likely short 248 * to allow bundling, so reset to full size. 249 */ 250 if (0 == i) 251 len = max; 252 } 253 254 /* .. now the leftover bytes. */ 255 if (over) { 256 if (!whole) 257 frag = SCTP_DATA_NOT_FRAG; 258 else 259 frag = SCTP_DATA_LAST_FRAG; 260 261 chunk = sctp_make_datafrag_empty(asoc, sinfo, over, frag, 0); 262 263 if (!chunk) 264 goto errout; 265 266 err = sctp_user_addto_chunk(chunk, offset, over,msgh->msg_iov); 267 268 /* Put the chunk->skb back into the form expected by send. */ 269 __skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr 270 - (__u8 *)chunk->skb->data); 271 if (err < 0) 272 goto errout; 273 274 sctp_datamsg_assign(msg, chunk); 275 list_add_tail(&chunk->frag_list, &msg->chunks); 276 } 277 278 return msg; 279 280errout: 281 list_for_each_safe(pos, temp, &msg->chunks) { 282 list_del_init(pos); 283 chunk = list_entry(pos, struct sctp_chunk, frag_list); 284 sctp_chunk_free(chunk); 285 } 286 sctp_datamsg_free(msg); 287 return NULL; 288} 289 290/* Check whether this message has expired. */ 291int sctp_chunk_abandoned(struct sctp_chunk *chunk) 292{ 293 struct sctp_datamsg *msg = chunk->msg; 294 295 if (!msg->can_abandon) 296 return 0; 297 298 if (time_after(jiffies, msg->expires_at)) 299 return 1; 300 301 return 0; 302} 303 304/* This chunk (and consequently entire message) has failed in its sending. */ 305void sctp_chunk_fail(struct sctp_chunk *chunk, int error) 306{ 307 chunk->msg->send_failed = 1; 308 chunk->msg->send_error = error; 309} 310