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