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