inqueue.c revision a09c83847b664dcd67a72613374061c900afb799
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. */ 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 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 */ 108struct 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 /* Verify that we have at least chunk headers 135 * worth of buffer left. 136 */ 137 if (skb_headlen(chunk->skb) < sizeof(sctp_chunkhdr_t)) { 138 sctp_chunk_free(chunk); 139 chunk = queue->in_progress = NULL; 140 } 141 } 142 } 143 144 /* Do we need to take the next packet out of the queue to process? */ 145 if (!chunk) { 146 struct list_head *entry; 147 148 /* Is the queue empty? */ 149 if (list_empty(&queue->in_chunk_list)) 150 return NULL; 151 152 entry = queue->in_chunk_list.next; 153 chunk = queue->in_progress = 154 list_entry(entry, struct sctp_chunk, list); 155 list_del_init(entry); 156 157 /* This is the first chunk in the packet. */ 158 chunk->singleton = 1; 159 ch = (sctp_chunkhdr_t *) chunk->skb->data; 160 chunk->data_accepted = 0; 161 } 162 163 chunk->chunk_hdr = ch; 164 chunk->chunk_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); 165 /* In the unlikely case of an IP reassembly, the skb could be 166 * non-linear. If so, update chunk_end so that it doesn't go past 167 * the skb->tail. 168 */ 169 if (unlikely(skb_is_nonlinear(chunk->skb))) { 170 if (chunk->chunk_end > skb_tail_pointer(chunk->skb)) 171 chunk->chunk_end = skb_tail_pointer(chunk->skb); 172 } 173 skb_pull(chunk->skb, sizeof(sctp_chunkhdr_t)); 174 chunk->subh.v = NULL; /* Subheader is no longer valid. */ 175 176 if (chunk->chunk_end < skb_tail_pointer(chunk->skb)) { 177 /* This is not a singleton */ 178 chunk->singleton = 0; 179 } else if (chunk->chunk_end > skb_tail_pointer(chunk->skb)) { 180 /* RFC 2960, Section 6.10 Bundling 181 * 182 * Partial chunks MUST NOT be placed in an SCTP packet. 183 * If the receiver detects a partial chunk, it MUST drop 184 * the chunk. 185 * 186 * Since the end of the chunk is past the end of our buffer 187 * (which contains the whole packet, we can freely discard 188 * the whole packet. 189 */ 190 sctp_chunk_free(chunk); 191 chunk = queue->in_progress = NULL; 192 193 return NULL; 194 } else { 195 /* We are at the end of the packet, so mark the chunk 196 * in case we need to send a SACK. 197 */ 198 chunk->end_of_packet = 1; 199 } 200 201 SCTP_DEBUG_PRINTK("+++sctp_inq_pop+++ chunk %p[%s]," 202 " length %d, skb->len %d\n",chunk, 203 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)), 204 ntohs(chunk->chunk_hdr->length), chunk->skb->len); 205 return chunk; 206} 207 208/* Set a top-half handler. 209 * 210 * Originally, we the top-half handler was scheduled as a BH. We now 211 * call the handler directly in sctp_inq_push() at a time that 212 * we know we are lock safe. 213 * The intent is that this routine will pull stuff out of the 214 * inqueue and process it. 215 */ 216void sctp_inq_set_th_handler(struct sctp_inq *q, work_func_t callback) 217{ 218 INIT_WORK(&q->immediate, callback); 219} 220 221