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 q->immediate.func(&q->immediate); 108 } 109 110 /* Peek at the next chunk on the inqeue. */ 111 struct sctp_chunkhdr *sctp_inq_peek(struct sctp_inq *queue) 112 { 113 struct sctp_chunk *chunk; 114 sctp_chunkhdr_t *ch = NULL; 115 116 chunk = queue->in_progress; 117 /* If there is no more chunks in this packet, say so */ 118 if (chunk->singleton || 119 chunk->end_of_packet || 120 chunk->pdiscard) 121 return NULL; 122 123 ch = (sctp_chunkhdr_t *)chunk->chunk_end; 124 125 return ch; 126 } 127 128 129 /* Extract a chunk from an SCTP inqueue. 130 * 131 * WARNING: If you need to put the chunk on another queue, you need to 132 * make a shallow copy (clone) of it. 133 */ 134 struct sctp_chunk *sctp_inq_pop(struct sctp_inq *queue) 135 { 136 struct sctp_chunk *chunk; 137 sctp_chunkhdr_t *ch = NULL; 138 139 /* The assumption is that we are safe to process the chunks 140 * at this time. 141 */ 142 143 if ((chunk = queue->in_progress)) { 144 /* There is a packet that we have been working on. 145 * Any post processing work to do before we move on? 146 */ 147 if (chunk->singleton || 148 chunk->end_of_packet || 149 chunk->pdiscard) { 150 sctp_chunk_free(chunk); 151 chunk = queue->in_progress = NULL; 152 } else { 153 /* Nothing to do. Next chunk in the packet, please. */ 154 ch = (sctp_chunkhdr_t *) chunk->chunk_end; 155 156 /* Force chunk->skb->data to chunk->chunk_end. */ 157 skb_pull(chunk->skb, 158 chunk->chunk_end - chunk->skb->data); 159 160 /* Verify that we have at least chunk headers 161 * worth of buffer left. 162 */ 163 if (skb_headlen(chunk->skb) < sizeof(sctp_chunkhdr_t)) { 164 sctp_chunk_free(chunk); 165 chunk = queue->in_progress = NULL; 166 } 167 } 168 } 169 170 /* Do we need to take the next packet out of the queue to process? */ 171 if (!chunk) { 172 struct list_head *entry; 173 174 /* Is the queue empty? */ 175 if (list_empty(&queue->in_chunk_list)) 176 return NULL; 177 178 entry = queue->in_chunk_list.next; 179 chunk = queue->in_progress = 180 list_entry(entry, struct sctp_chunk, list); 181 list_del_init(entry); 182 183 /* This is the first chunk in the packet. */ 184 chunk->singleton = 1; 185 ch = (sctp_chunkhdr_t *) chunk->skb->data; 186 chunk->data_accepted = 0; 187 } 188 189 chunk->chunk_hdr = ch; 190 chunk->chunk_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); 191 /* In the unlikely case of an IP reassembly, the skb could be 192 * non-linear. If so, update chunk_end so that it doesn't go past 193 * the skb->tail. 194 */ 195 if (unlikely(skb_is_nonlinear(chunk->skb))) { 196 if (chunk->chunk_end > skb_tail_pointer(chunk->skb)) 197 chunk->chunk_end = skb_tail_pointer(chunk->skb); 198 } 199 skb_pull(chunk->skb, sizeof(sctp_chunkhdr_t)); 200 chunk->subh.v = NULL; /* Subheader is no longer valid. */ 201 202 if (chunk->chunk_end < skb_tail_pointer(chunk->skb)) { 203 /* This is not a singleton */ 204 chunk->singleton = 0; 205 } else if (chunk->chunk_end > skb_tail_pointer(chunk->skb)) { 206 /* RFC 2960, Section 6.10 Bundling 207 * 208 * Partial chunks MUST NOT be placed in an SCTP packet. 209 * If the receiver detects a partial chunk, it MUST drop 210 * the chunk. 211 * 212 * Since the end of the chunk is past the end of our buffer 213 * (which contains the whole packet, we can freely discard 214 * the whole packet. 215 */ 216 sctp_chunk_free(chunk); 217 chunk = queue->in_progress = NULL; 218 219 return NULL; 220 } else { 221 /* We are at the end of the packet, so mark the chunk 222 * in case we need to send a SACK. 223 */ 224 chunk->end_of_packet = 1; 225 } 226 227 SCTP_DEBUG_PRINTK("+++sctp_inq_pop+++ chunk %p[%s]," 228 " length %d, skb->len %d\n",chunk, 229 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)), 230 ntohs(chunk->chunk_hdr->length), chunk->skb->len); 231 return chunk; 232 } 233 234 /* Set a top-half handler. 235 * 236 * Originally, we the top-half handler was scheduled as a BH. We now 237 * call the handler directly in sctp_inq_push() at a time that 238 * we know we are lock safe. 239 * The intent is that this routine will pull stuff out of the 240 * inqueue and process it. 241 */ 242 void sctp_inq_set_th_handler(struct sctp_inq *q, work_func_t callback) 243 { 244 INIT_WORK(&q->immediate, callback); 245 } 246 247