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