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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 47 48 #include <net/sctp/sctp.h> 49 #include <net/sctp/sm.h> 50 #include <linux/interrupt.h> 51 #include <linux/slab.h> 52 53 /* Initialize an SCTP inqueue. */ 54 void sctp_inq_init(struct sctp_inq *queue) 55 { 56 INIT_LIST_HEAD(&queue->in_chunk_list); 57 queue->in_progress = NULL; 58 59 /* Create a task for delivering data. */ 60 INIT_WORK(&queue->immediate, NULL); 61 62 queue->malloced = 0; 63 } 64 65 /* Release the memory associated with an SCTP inqueue. */ 66 void sctp_inq_free(struct sctp_inq *queue) 67 { 68 struct sctp_chunk *chunk, *tmp; 69 70 /* Empty the queue. */ 71 list_for_each_entry_safe(chunk, tmp, &queue->in_chunk_list, list) { 72 list_del_init(&chunk->list); 73 sctp_chunk_free(chunk); 74 } 75 76 /* If there is a packet which is currently being worked on, 77 * free it as well. 78 */ 79 if (queue->in_progress) { 80 sctp_chunk_free(queue->in_progress); 81 queue->in_progress = NULL; 82 } 83 84 if (queue->malloced) { 85 /* Dump the master memory segment. */ 86 kfree(queue); 87 } 88 } 89 90 /* Put a new packet in an SCTP inqueue. 91 * We assume that packet->sctp_hdr is set and in host byte order. 92 */ 93 void sctp_inq_push(struct sctp_inq *q, struct sctp_chunk *chunk) 94 { 95 /* Directly call the packet handling routine. */ 96 if (chunk->rcvr->dead) { 97 sctp_chunk_free(chunk); 98 return; 99 } 100 101 /* We are now calling this either from the soft interrupt 102 * or from the backlog processing. 103 * Eventually, we should clean up inqueue to not rely 104 * on the BH related data structures. 105 */ 106 list_add_tail(&chunk->list, &q->in_chunk_list); 107 if (chunk->asoc) 108 chunk->asoc->stats.ipackets++; 109 q->immediate.func(&q->immediate); 110 } 111 112 /* Peek at the next chunk on the inqeue. */ 113 struct sctp_chunkhdr *sctp_inq_peek(struct sctp_inq *queue) 114 { 115 struct sctp_chunk *chunk; 116 sctp_chunkhdr_t *ch = NULL; 117 118 chunk = queue->in_progress; 119 /* If there is no more chunks in this packet, say so */ 120 if (chunk->singleton || 121 chunk->end_of_packet || 122 chunk->pdiscard) 123 return NULL; 124 125 ch = (sctp_chunkhdr_t *)chunk->chunk_end; 126 127 return ch; 128 } 129 130 131 /* Extract a chunk from an SCTP inqueue. 132 * 133 * WARNING: If you need to put the chunk on another queue, you need to 134 * make a shallow copy (clone) of it. 135 */ 136 struct sctp_chunk *sctp_inq_pop(struct sctp_inq *queue) 137 { 138 struct sctp_chunk *chunk; 139 sctp_chunkhdr_t *ch = NULL; 140 141 /* The assumption is that we are safe to process the chunks 142 * at this time. 143 */ 144 145 if ((chunk = queue->in_progress)) { 146 /* There is a packet that we have been working on. 147 * Any post processing work to do before we move on? 148 */ 149 if (chunk->singleton || 150 chunk->end_of_packet || 151 chunk->pdiscard) { 152 sctp_chunk_free(chunk); 153 chunk = queue->in_progress = NULL; 154 } else { 155 /* Nothing to do. Next chunk in the packet, please. */ 156 ch = (sctp_chunkhdr_t *) chunk->chunk_end; 157 158 /* Force chunk->skb->data to chunk->chunk_end. */ 159 skb_pull(chunk->skb, 160 chunk->chunk_end - chunk->skb->data); 161 162 /* Verify that we have at least chunk headers 163 * worth of buffer left. 164 */ 165 if (skb_headlen(chunk->skb) < sizeof(sctp_chunkhdr_t)) { 166 sctp_chunk_free(chunk); 167 chunk = queue->in_progress = NULL; 168 } 169 } 170 } 171 172 /* Do we need to take the next packet out of the queue to process? */ 173 if (!chunk) { 174 struct list_head *entry; 175 176 /* Is the queue empty? */ 177 if (list_empty(&queue->in_chunk_list)) 178 return NULL; 179 180 entry = queue->in_chunk_list.next; 181 chunk = queue->in_progress = 182 list_entry(entry, struct sctp_chunk, list); 183 list_del_init(entry); 184 185 /* This is the first chunk in the packet. */ 186 chunk->singleton = 1; 187 ch = (sctp_chunkhdr_t *) chunk->skb->data; 188 chunk->data_accepted = 0; 189 } 190 191 chunk->chunk_hdr = ch; 192 chunk->chunk_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); 193 /* In the unlikely case of an IP reassembly, the skb could be 194 * non-linear. If so, update chunk_end so that it doesn't go past 195 * the skb->tail. 196 */ 197 if (unlikely(skb_is_nonlinear(chunk->skb))) { 198 if (chunk->chunk_end > skb_tail_pointer(chunk->skb)) 199 chunk->chunk_end = skb_tail_pointer(chunk->skb); 200 } 201 skb_pull(chunk->skb, sizeof(sctp_chunkhdr_t)); 202 chunk->subh.v = NULL; /* Subheader is no longer valid. */ 203 204 if (chunk->chunk_end < skb_tail_pointer(chunk->skb)) { 205 /* This is not a singleton */ 206 chunk->singleton = 0; 207 } else if (chunk->chunk_end > skb_tail_pointer(chunk->skb)) { 208 /* RFC 2960, Section 6.10 Bundling 209 * 210 * Partial chunks MUST NOT be placed in an SCTP packet. 211 * If the receiver detects a partial chunk, it MUST drop 212 * the chunk. 213 * 214 * Since the end of the chunk is past the end of our buffer 215 * (which contains the whole packet, we can freely discard 216 * the whole packet. 217 */ 218 sctp_chunk_free(chunk); 219 chunk = queue->in_progress = NULL; 220 221 return NULL; 222 } else { 223 /* We are at the end of the packet, so mark the chunk 224 * in case we need to send a SACK. 225 */ 226 chunk->end_of_packet = 1; 227 } 228 229 SCTP_DEBUG_PRINTK("+++sctp_inq_pop+++ chunk %p[%s]," 230 " length %d, skb->len %d\n",chunk, 231 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)), 232 ntohs(chunk->chunk_hdr->length), chunk->skb->len); 233 return chunk; 234 } 235 236 /* Set a top-half handler. 237 * 238 * Originally, we the top-half handler was scheduled as a BH. We now 239 * call the handler directly in sctp_inq_push() at a time that 240 * we know we are lock safe. 241 * The intent is that this routine will pull stuff out of the 242 * inqueue and process it. 243 */ 244 void sctp_inq_set_th_handler(struct sctp_inq *q, work_func_t callback) 245 { 246 INIT_WORK(&q->immediate, callback); 247 } 248 249