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, see 28 * <http://www.gnu.org/licenses/>. 29 * 30 * Please send any bug reports or fixes you make to the 31 * email address(es): 32 * lksctp developers <linux-sctp@vger.kernel.org> 33 * 34 * Written or modified by: 35 * La Monte H.P. Yarroll <piggy@acm.org> 36 * Karl Knutson <karl@athena.chicago.il.us> 37 */ 38 39 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 40 41 #include <net/sctp/sctp.h> 42 #include <net/sctp/sm.h> 43 #include <linux/interrupt.h> 44 #include <linux/slab.h> 45 46 /* Initialize an SCTP inqueue. */ 47 void sctp_inq_init(struct sctp_inq *queue) 48 { 49 INIT_LIST_HEAD(&queue->in_chunk_list); 50 queue->in_progress = NULL; 51 52 /* Create a task for delivering data. */ 53 INIT_WORK(&queue->immediate, NULL); 54 } 55 56 /* Release the memory associated with an SCTP inqueue. */ 57 void sctp_inq_free(struct sctp_inq *queue) 58 { 59 struct sctp_chunk *chunk, *tmp; 60 61 /* Empty the queue. */ 62 list_for_each_entry_safe(chunk, tmp, &queue->in_chunk_list, list) { 63 list_del_init(&chunk->list); 64 sctp_chunk_free(chunk); 65 } 66 67 /* If there is a packet which is currently being worked on, 68 * free it as well. 69 */ 70 if (queue->in_progress) { 71 sctp_chunk_free(queue->in_progress); 72 queue->in_progress = NULL; 73 } 74 } 75 76 /* Put a new packet in an SCTP inqueue. 77 * We assume that packet->sctp_hdr is set and in host byte order. 78 */ 79 void sctp_inq_push(struct sctp_inq *q, struct sctp_chunk *chunk) 80 { 81 /* Directly call the packet handling routine. */ 82 if (chunk->rcvr->dead) { 83 sctp_chunk_free(chunk); 84 return; 85 } 86 87 /* We are now calling this either from the soft interrupt 88 * or from the backlog processing. 89 * Eventually, we should clean up inqueue to not rely 90 * on the BH related data structures. 91 */ 92 local_bh_disable(); 93 list_add_tail(&chunk->list, &q->in_chunk_list); 94 if (chunk->asoc) 95 chunk->asoc->stats.ipackets++; 96 q->immediate.func(&q->immediate); 97 local_bh_enable(); 98 } 99 100 /* Peek at the next chunk on the inqeue. */ 101 struct sctp_chunkhdr *sctp_inq_peek(struct sctp_inq *queue) 102 { 103 struct sctp_chunk *chunk; 104 sctp_chunkhdr_t *ch = NULL; 105 106 chunk = queue->in_progress; 107 /* If there is no more chunks in this packet, say so */ 108 if (chunk->singleton || 109 chunk->end_of_packet || 110 chunk->pdiscard) 111 return NULL; 112 113 ch = (sctp_chunkhdr_t *)chunk->chunk_end; 114 115 return ch; 116 } 117 118 119 /* Extract a chunk from an SCTP inqueue. 120 * 121 * WARNING: If you need to put the chunk on another queue, you need to 122 * make a shallow copy (clone) of it. 123 */ 124 struct sctp_chunk *sctp_inq_pop(struct sctp_inq *queue) 125 { 126 struct sctp_chunk *chunk; 127 sctp_chunkhdr_t *ch = NULL; 128 129 /* The assumption is that we are safe to process the chunks 130 * at this time. 131 */ 132 133 chunk = queue->in_progress; 134 if (chunk) { 135 /* There is a packet that we have been working on. 136 * Any post processing work to do before we move on? 137 */ 138 if (chunk->singleton || 139 chunk->end_of_packet || 140 chunk->pdiscard) { 141 if (chunk->head_skb == chunk->skb) { 142 chunk->skb = skb_shinfo(chunk->skb)->frag_list; 143 goto new_skb; 144 } 145 if (chunk->skb->next) { 146 chunk->skb = chunk->skb->next; 147 goto new_skb; 148 } 149 150 if (chunk->head_skb) 151 chunk->skb = chunk->head_skb; 152 sctp_chunk_free(chunk); 153 chunk = queue->in_progress = NULL; 154 } else { 155 /* Nothing to do. Next chunk in the packet, please. */ 156 ch = (sctp_chunkhdr_t *) chunk->chunk_end; 157 /* Force chunk->skb->data to chunk->chunk_end. */ 158 skb_pull(chunk->skb, chunk->chunk_end - chunk->skb->data); 159 /* We are guaranteed to pull a SCTP header. */ 160 } 161 } 162 163 /* Do we need to take the next packet out of the queue to process? */ 164 if (!chunk) { 165 struct list_head *entry; 166 167 next_chunk: 168 /* Is the queue empty? */ 169 entry = sctp_list_dequeue(&queue->in_chunk_list); 170 if (!entry) 171 return NULL; 172 173 chunk = list_entry(entry, struct sctp_chunk, list); 174 175 /* Linearize if it's not GSO */ 176 if ((skb_shinfo(chunk->skb)->gso_type & SKB_GSO_SCTP) != SKB_GSO_SCTP && 177 skb_is_nonlinear(chunk->skb)) { 178 if (skb_linearize(chunk->skb)) { 179 __SCTP_INC_STATS(dev_net(chunk->skb->dev), SCTP_MIB_IN_PKT_DISCARDS); 180 sctp_chunk_free(chunk); 181 goto next_chunk; 182 } 183 184 /* Update sctp_hdr as it probably changed */ 185 chunk->sctp_hdr = sctp_hdr(chunk->skb); 186 } 187 188 if ((skb_shinfo(chunk->skb)->gso_type & SKB_GSO_SCTP) == SKB_GSO_SCTP) { 189 /* GSO-marked skbs but without frags, handle 190 * them normally 191 */ 192 if (skb_shinfo(chunk->skb)->frag_list) 193 chunk->head_skb = chunk->skb; 194 195 /* skbs with "cover letter" */ 196 if (chunk->head_skb && chunk->skb->data_len == chunk->skb->len) 197 chunk->skb = skb_shinfo(chunk->skb)->frag_list; 198 199 if (WARN_ON(!chunk->skb)) { 200 __SCTP_INC_STATS(dev_net(chunk->skb->dev), SCTP_MIB_IN_PKT_DISCARDS); 201 sctp_chunk_free(chunk); 202 goto next_chunk; 203 } 204 } 205 206 if (chunk->asoc) 207 sock_rps_save_rxhash(chunk->asoc->base.sk, chunk->skb); 208 209 queue->in_progress = chunk; 210 211 new_skb: 212 /* This is the first chunk in the packet. */ 213 ch = (sctp_chunkhdr_t *) chunk->skb->data; 214 chunk->singleton = 1; 215 chunk->data_accepted = 0; 216 chunk->pdiscard = 0; 217 chunk->auth = 0; 218 chunk->has_asconf = 0; 219 chunk->end_of_packet = 0; 220 chunk->ecn_ce_done = 0; 221 } 222 223 chunk->chunk_hdr = ch; 224 chunk->chunk_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); 225 skb_pull(chunk->skb, sizeof(sctp_chunkhdr_t)); 226 chunk->subh.v = NULL; /* Subheader is no longer valid. */ 227 228 if (chunk->chunk_end + sizeof(sctp_chunkhdr_t) < 229 skb_tail_pointer(chunk->skb)) { 230 /* This is not a singleton */ 231 chunk->singleton = 0; 232 } else if (chunk->chunk_end > skb_tail_pointer(chunk->skb)) { 233 /* Discard inside state machine. */ 234 chunk->pdiscard = 1; 235 chunk->chunk_end = skb_tail_pointer(chunk->skb); 236 } else { 237 /* We are at the end of the packet, so mark the chunk 238 * in case we need to send a SACK. 239 */ 240 chunk->end_of_packet = 1; 241 } 242 243 pr_debug("+++sctp_inq_pop+++ chunk:%p[%s], length:%d, skb->len:%d\n", 244 chunk, sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)), 245 ntohs(chunk->chunk_hdr->length), chunk->skb->len); 246 247 return chunk; 248 } 249 250 /* Set a top-half handler. 251 * 252 * Originally, we the top-half handler was scheduled as a BH. We now 253 * call the handler directly in sctp_inq_push() at a time that 254 * we know we are lock safe. 255 * The intent is that this routine will pull stuff out of the 256 * inqueue and process it. 257 */ 258 void sctp_inq_set_th_handler(struct sctp_inq *q, work_func_t callback) 259 { 260 INIT_WORK(&q->immediate, callback); 261 } 262