1 /* SCTP kernel implementation 2 * Copyright (c) 1999-2000 Cisco, Inc. 3 * Copyright (c) 1999-2001 Motorola, Inc. 4 * Copyright (c) 2002 International Business Machines, Corp. 5 * 6 * This file is part of the SCTP kernel implementation 7 * 8 * These functions are the methods for accessing the SCTP inqueue. 9 * 10 * An SCTP inqueue is a queue into which you push SCTP packets 11 * (which might be bundles or fragments of chunks) and out of which you 12 * pop SCTP whole chunks. 13 * 14 * This SCTP implementation is free software; 15 * you can redistribute it and/or modify it under the terms of 16 * the GNU General Public License as published by 17 * the Free Software Foundation; either version 2, or (at your option) 18 * any later version. 19 * 20 * This SCTP implementation is distributed in the hope that it 21 * will be useful, but WITHOUT ANY WARRANTY; without even the implied 22 * ************************ 23 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 24 * See the GNU General Public License for more details. 25 * 26 * You should have received a copy of the GNU General Public License 27 * along with GNU CC; see the file COPYING. If not, write to 28 * the Free Software Foundation, 59 Temple Place - Suite 330, 29 * Boston, MA 02111-1307, USA. 30 * 31 * Please send any bug reports or fixes you make to the 32 * email address(es): 33 * lksctp developers <lksctp-developers@lists.sourceforge.net> 34 * 35 * Or submit a bug report through the following website: 36 * http://www.sf.net/projects/lksctp 37 * 38 * Written or modified by: 39 * La Monte H.P. Yarroll <piggy@acm.org> 40 * Karl Knutson <karl@athena.chicago.il.us> 41 * 42 * Any bugs reported given to us we will try to fix... any fixes shared will 43 * be incorporated into the next SCTP release. 44 */ 45 46 #include <net/sctp/sctp.h> 47 #include <net/sctp/sm.h> 48 #include <linux/interrupt.h> 49 #include <linux/slab.h> 50 51 /* Initialize an SCTP inqueue. */ 52 void sctp_inq_init(struct sctp_inq *queue) 53 { 54 INIT_LIST_HEAD(&queue->in_chunk_list); 55 queue->in_progress = NULL; 56 57 /* Create a task for delivering data. */ 58 INIT_WORK(&queue->immediate, NULL); 59 60 queue->malloced = 0; 61 } 62 63 /* Release the memory associated with an SCTP inqueue. */ 64 void sctp_inq_free(struct sctp_inq *queue) 65 { 66 struct sctp_chunk *chunk, *tmp; 67 68 /* Empty the queue. */ 69 list_for_each_entry_safe(chunk, tmp, &queue->in_chunk_list, list) { 70 list_del_init(&chunk->list); 71 sctp_chunk_free(chunk); 72 } 73 74 /* If there is a packet which is currently being worked on, 75 * free it as well. 76 */ 77 if (queue->in_progress) { 78 sctp_chunk_free(queue->in_progress); 79 queue->in_progress = NULL; 80 } 81 82 if (queue->malloced) { 83 /* Dump the master memory segment. */ 84 kfree(queue); 85 } 86 } 87 88 /* Put a new packet in an SCTP inqueue. 89 * We assume that packet->sctp_hdr is set and in host byte order. 90 */ 91 void sctp_inq_push(struct sctp_inq *q, struct sctp_chunk *chunk) 92 { 93 /* Directly call the packet handling routine. */ 94 if (chunk->rcvr->dead) { 95 sctp_chunk_free(chunk); 96 return; 97 } 98 99 /* We are now calling this either from the soft interrupt 100 * or from the backlog processing. 101 * Eventually, we should clean up inqueue to not rely 102 * on the BH related data structures. 103 */ 104 list_add_tail(&chunk->list, &q->in_chunk_list); 105 q->immediate.func(&q->immediate); 106 } 107 108 /* Peek at the next chunk on the inqeue. */ 109 struct sctp_chunkhdr *sctp_inq_peek(struct sctp_inq *queue) 110 { 111 struct sctp_chunk *chunk; 112 sctp_chunkhdr_t *ch = NULL; 113 114 chunk = queue->in_progress; 115 /* If there is no more chunks in this packet, say so */ 116 if (chunk->singleton || 117 chunk->end_of_packet || 118 chunk->pdiscard) 119 return NULL; 120 121 ch = (sctp_chunkhdr_t *)chunk->chunk_end; 122 123 return ch; 124 } 125 126 127 /* Extract a chunk from an SCTP inqueue. 128 * 129 * WARNING: If you need to put the chunk on another queue, you need to 130 * make a shallow copy (clone) of it. 131 */ 132 struct sctp_chunk *sctp_inq_pop(struct sctp_inq *queue) 133 { 134 struct sctp_chunk *chunk; 135 sctp_chunkhdr_t *ch = NULL; 136 137 /* The assumption is that we are safe to process the chunks 138 * at this time. 139 */ 140 141 if ((chunk = queue->in_progress)) { 142 /* There is a packet that we have been working on. 143 * Any post processing work to do before we move on? 144 */ 145 if (chunk->singleton || 146 chunk->end_of_packet || 147 chunk->pdiscard) { 148 sctp_chunk_free(chunk); 149 chunk = queue->in_progress = NULL; 150 } else { 151 /* Nothing to do. Next chunk in the packet, please. */ 152 ch = (sctp_chunkhdr_t *) chunk->chunk_end; 153 154 /* Force chunk->skb->data to chunk->chunk_end. */ 155 skb_pull(chunk->skb, 156 chunk->chunk_end - chunk->skb->data); 157 158 /* Verify that we have at least chunk headers 159 * worth of buffer left. 160 */ 161 if (skb_headlen(chunk->skb) < sizeof(sctp_chunkhdr_t)) { 162 sctp_chunk_free(chunk); 163 chunk = queue->in_progress = NULL; 164 } 165 } 166 } 167 168 /* Do we need to take the next packet out of the queue to process? */ 169 if (!chunk) { 170 struct list_head *entry; 171 172 /* Is the queue empty? */ 173 if (list_empty(&queue->in_chunk_list)) 174 return NULL; 175 176 entry = queue->in_chunk_list.next; 177 chunk = queue->in_progress = 178 list_entry(entry, struct sctp_chunk, list); 179 list_del_init(entry); 180 181 /* This is the first chunk in the packet. */ 182 chunk->singleton = 1; 183 ch = (sctp_chunkhdr_t *) chunk->skb->data; 184 chunk->data_accepted = 0; 185 } 186 187 chunk->chunk_hdr = ch; 188 chunk->chunk_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); 189 /* In the unlikely case of an IP reassembly, the skb could be 190 * non-linear. If so, update chunk_end so that it doesn't go past 191 * the skb->tail. 192 */ 193 if (unlikely(skb_is_nonlinear(chunk->skb))) { 194 if (chunk->chunk_end > skb_tail_pointer(chunk->skb)) 195 chunk->chunk_end = skb_tail_pointer(chunk->skb); 196 } 197 skb_pull(chunk->skb, sizeof(sctp_chunkhdr_t)); 198 chunk->subh.v = NULL; /* Subheader is no longer valid. */ 199 200 if (chunk->chunk_end < skb_tail_pointer(chunk->skb)) { 201 /* This is not a singleton */ 202 chunk->singleton = 0; 203 } else if (chunk->chunk_end > skb_tail_pointer(chunk->skb)) { 204 /* RFC 2960, Section 6.10 Bundling 205 * 206 * Partial chunks MUST NOT be placed in an SCTP packet. 207 * If the receiver detects a partial chunk, it MUST drop 208 * the chunk. 209 * 210 * Since the end of the chunk is past the end of our buffer 211 * (which contains the whole packet, we can freely discard 212 * the whole packet. 213 */ 214 sctp_chunk_free(chunk); 215 chunk = queue->in_progress = NULL; 216 217 return NULL; 218 } else { 219 /* We are at the end of the packet, so mark the chunk 220 * in case we need to send a SACK. 221 */ 222 chunk->end_of_packet = 1; 223 } 224 225 SCTP_DEBUG_PRINTK("+++sctp_inq_pop+++ chunk %p[%s]," 226 " length %d, skb->len %d\n",chunk, 227 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)), 228 ntohs(chunk->chunk_hdr->length), chunk->skb->len); 229 return chunk; 230 } 231 232 /* Set a top-half handler. 233 * 234 * Originally, we the top-half handler was scheduled as a BH. We now 235 * call the handler directly in sctp_inq_push() at a time that 236 * we know we are lock safe. 237 * The intent is that this routine will pull stuff out of the 238 * inqueue and process it. 239 */ 240 void sctp_inq_set_th_handler(struct sctp_inq *q, work_func_t callback) 241 { 242 INIT_WORK(&q->immediate, callback); 243 } 244 245