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 63 /* Release the memory associated with an SCTP inqueue. */ 64 void sctp_inq_free(struct sctp_inq *queue) 65 { 66 struct sctp_chunk *chunk, *tmp; 67 68 /* Empty the queue. */ 69 list_for_each_entry_safe(chunk, tmp, &queue->in_chunk_list, list) { 70 list_del_init(&chunk->list); 71 sctp_chunk_free(chunk); 72 } 73 74 /* If there is a packet which is currently being worked on, 75 * free it as well. 76 */ 77 if (queue->in_progress) { 78 sctp_chunk_free(queue->in_progress); 79 queue->in_progress = NULL; 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 *chunk) 87 { 88 /* Directly call the packet handling routine. */ 89 if (chunk->rcvr->dead) { 90 sctp_chunk_free(chunk); 91 return; 92 } 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 if (chunk->asoc) 101 chunk->asoc->stats.ipackets++; 102 q->immediate.func(&q->immediate); 103 } 104 105 /* Peek at the next chunk on the inqeue. */ 106 struct sctp_chunkhdr *sctp_inq_peek(struct sctp_inq *queue) 107 { 108 struct sctp_chunk *chunk; 109 sctp_chunkhdr_t *ch = NULL; 110 111 chunk = queue->in_progress; 112 /* If there is no more chunks in this packet, say so */ 113 if (chunk->singleton || 114 chunk->end_of_packet || 115 chunk->pdiscard) 116 return NULL; 117 118 ch = (sctp_chunkhdr_t *)chunk->chunk_end; 119 120 return ch; 121 } 122 123 124 /* Extract a chunk from an SCTP inqueue. 125 * 126 * WARNING: If you need to put the chunk on another queue, you need to 127 * make a shallow copy (clone) of it. 128 */ 129 struct sctp_chunk *sctp_inq_pop(struct sctp_inq *queue) 130 { 131 struct sctp_chunk *chunk; 132 sctp_chunkhdr_t *ch = NULL; 133 134 /* The assumption is that we are safe to process the chunks 135 * at this time. 136 */ 137 138 if ((chunk = queue->in_progress)) { 139 /* There is a packet that we have been working on. 140 * Any post processing work to do before we move on? 141 */ 142 if (chunk->singleton || 143 chunk->end_of_packet || 144 chunk->pdiscard) { 145 sctp_chunk_free(chunk); 146 chunk = queue->in_progress = NULL; 147 } else { 148 /* Nothing to do. Next chunk in the packet, please. */ 149 ch = (sctp_chunkhdr_t *) chunk->chunk_end; 150 151 /* Force chunk->skb->data to chunk->chunk_end. */ 152 skb_pull(chunk->skb, 153 chunk->chunk_end - chunk->skb->data); 154 155 /* Verify that we have at least chunk headers 156 * worth of buffer left. 157 */ 158 if (skb_headlen(chunk->skb) < sizeof(sctp_chunkhdr_t)) { 159 sctp_chunk_free(chunk); 160 chunk = queue->in_progress = NULL; 161 } 162 } 163 } 164 165 /* Do we need to take the next packet out of the queue to process? */ 166 if (!chunk) { 167 struct list_head *entry; 168 169 /* Is the queue empty? */ 170 if (list_empty(&queue->in_chunk_list)) 171 return NULL; 172 173 entry = queue->in_chunk_list.next; 174 chunk = queue->in_progress = 175 list_entry(entry, struct sctp_chunk, list); 176 list_del_init(entry); 177 178 /* This is the first chunk in the packet. */ 179 chunk->singleton = 1; 180 ch = (sctp_chunkhdr_t *) chunk->skb->data; 181 chunk->data_accepted = 0; 182 } 183 184 chunk->chunk_hdr = ch; 185 chunk->chunk_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); 186 /* In the unlikely case of an IP reassembly, the skb could be 187 * non-linear. If so, update chunk_end so that it doesn't go past 188 * the skb->tail. 189 */ 190 if (unlikely(skb_is_nonlinear(chunk->skb))) { 191 if (chunk->chunk_end > skb_tail_pointer(chunk->skb)) 192 chunk->chunk_end = skb_tail_pointer(chunk->skb); 193 } 194 skb_pull(chunk->skb, sizeof(sctp_chunkhdr_t)); 195 chunk->subh.v = NULL; /* Subheader is no longer valid. */ 196 197 if (chunk->chunk_end < skb_tail_pointer(chunk->skb)) { 198 /* This is not a singleton */ 199 chunk->singleton = 0; 200 } else if (chunk->chunk_end > skb_tail_pointer(chunk->skb)) { 201 /* RFC 2960, Section 6.10 Bundling 202 * 203 * Partial chunks MUST NOT be placed in an SCTP packet. 204 * If the receiver detects a partial chunk, it MUST drop 205 * the chunk. 206 * 207 * Since the end of the chunk is past the end of our buffer 208 * (which contains the whole packet, we can freely discard 209 * the whole packet. 210 */ 211 sctp_chunk_free(chunk); 212 chunk = queue->in_progress = NULL; 213 214 return NULL; 215 } else { 216 /* We are at the end of the packet, so mark the chunk 217 * in case we need to send a SACK. 218 */ 219 chunk->end_of_packet = 1; 220 } 221 222 pr_debug("+++sctp_inq_pop+++ chunk:%p[%s], length:%d, skb->len:%d\n", 223 chunk, sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)), 224 ntohs(chunk->chunk_hdr->length), chunk->skb->len); 225 226 return chunk; 227 } 228 229 /* Set a top-half handler. 230 * 231 * Originally, we the top-half handler was scheduled as a BH. We now 232 * call the handler directly in sctp_inq_push() at a time that 233 * we know we are lock safe. 234 * The intent is that this routine will pull stuff out of the 235 * inqueue and process it. 236 */ 237 void sctp_inq_set_th_handler(struct sctp_inq *q, work_func_t callback) 238 { 239 INIT_WORK(&q->immediate, callback); 240 } 241