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.
6 * This file is part of the SCTP kernel implementation
8 * These functions are the methods for accessing the SCTP inqueue.
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.
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)
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.
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/>.
30 * Please send any bug reports or fixes you make to the
32 * lksctp developers <linux-sctp@vger.kernel.org>
34 * Written or modified by:
35 * La Monte H.P. Yarroll <piggy@acm.org>
36 * Karl Knutson <karl@athena.chicago.il.us>
39 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
41 #include <net/sctp/sctp.h>
42 #include <net/sctp/sm.h>
43 #include <linux/interrupt.h>
44 #include <linux/slab.h>
46 /* Initialize an SCTP inqueue. */
47 void sctp_inq_init(struct sctp_inq *queue)
49 INIT_LIST_HEAD(&queue->in_chunk_list);
50 queue->in_progress = NULL;
52 /* Create a task for delivering data. */
53 INIT_WORK(&queue->immediate, NULL);
56 /* Release the memory associated with an SCTP inqueue. */
57 void sctp_inq_free(struct sctp_inq *queue)
59 struct sctp_chunk *chunk, *tmp;
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);
67 /* If there is a packet which is currently being worked on,
70 if (queue->in_progress) {
71 sctp_chunk_free(queue->in_progress);
72 queue->in_progress = NULL;
76 /* Put a new packet in an SCTP inqueue.
77 * We assume that packet->sctp_hdr is set and in host byte order.
79 void sctp_inq_push(struct sctp_inq *q, struct sctp_chunk *chunk)
81 /* Directly call the packet handling routine. */
82 if (chunk->rcvr->dead) {
83 sctp_chunk_free(chunk);
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.
93 list_add_tail(&chunk->list, &q->in_chunk_list);
95 chunk->asoc->stats.ipackets++;
96 q->immediate.func(&q->immediate);
100 /* Peek at the next chunk on the inqeue. */
101 struct sctp_chunkhdr *sctp_inq_peek(struct sctp_inq *queue)
103 struct sctp_chunk *chunk;
104 sctp_chunkhdr_t *ch = NULL;
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 ||
113 ch = (sctp_chunkhdr_t *)chunk->chunk_end;
119 /* Extract a chunk from an SCTP inqueue.
121 * WARNING: If you need to put the chunk on another queue, you need to
122 * make a shallow copy (clone) of it.
124 struct sctp_chunk *sctp_inq_pop(struct sctp_inq *queue)
126 struct sctp_chunk *chunk;
127 sctp_chunkhdr_t *ch = NULL;
129 /* The assumption is that we are safe to process the chunks
133 chunk = queue->in_progress;
135 /* There is a packet that we have been working on.
136 * Any post processing work to do before we move on?
138 if (chunk->singleton ||
139 chunk->end_of_packet ||
141 sctp_chunk_free(chunk);
142 chunk = queue->in_progress = NULL;
144 /* Nothing to do. Next chunk in the packet, please. */
145 ch = (sctp_chunkhdr_t *) chunk->chunk_end;
146 /* Force chunk->skb->data to chunk->chunk_end. */
147 skb_pull(chunk->skb, chunk->chunk_end - chunk->skb->data);
148 /* We are guaranteed to pull a SCTP header. */
152 /* Do we need to take the next packet out of the queue to process? */
154 struct list_head *entry;
157 /* Is the queue empty? */
158 if (list_empty(&queue->in_chunk_list))
161 entry = queue->in_chunk_list.next;
162 chunk = list_entry(entry, struct sctp_chunk, list);
163 list_del_init(entry);
165 /* Linearize if it's not GSO */
166 if (skb_is_nonlinear(chunk->skb)) {
167 if (skb_linearize(chunk->skb)) {
168 __SCTP_INC_STATS(dev_net(chunk->skb->dev), SCTP_MIB_IN_PKT_DISCARDS);
169 sctp_chunk_free(chunk);
173 /* Update sctp_hdr as it probably changed */
174 chunk->sctp_hdr = sctp_hdr(chunk->skb);
177 queue->in_progress = chunk;
179 /* This is the first chunk in the packet. */
180 chunk->singleton = 1;
181 ch = (sctp_chunkhdr_t *) chunk->skb->data;
182 chunk->data_accepted = 0;
185 sock_rps_save_rxhash(chunk->asoc->base.sk, chunk->skb);
188 chunk->chunk_hdr = ch;
189 chunk->chunk_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
190 skb_pull(chunk->skb, sizeof(sctp_chunkhdr_t));
191 chunk->subh.v = NULL; /* Subheader is no longer valid. */
193 if (chunk->chunk_end + sizeof(sctp_chunkhdr_t) <
194 skb_tail_pointer(chunk->skb)) {
195 /* This is not a singleton */
196 chunk->singleton = 0;
197 } else if (chunk->chunk_end > skb_tail_pointer(chunk->skb)) {
198 /* Discard inside state machine. */
200 chunk->chunk_end = skb_tail_pointer(chunk->skb);
202 /* We are at the end of the packet, so mark the chunk
203 * in case we need to send a SACK.
205 chunk->end_of_packet = 1;
208 pr_debug("+++sctp_inq_pop+++ chunk:%p[%s], length:%d, skb->len:%d\n",
209 chunk, sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)),
210 ntohs(chunk->chunk_hdr->length), chunk->skb->len);
215 /* Set a top-half handler.
217 * Originally, we the top-half handler was scheduled as a BH. We now
218 * call the handler directly in sctp_inq_push() at a time that
219 * we know we are lock safe.
220 * The intent is that this routine will pull stuff out of the
221 * inqueue and process it.
223 void sctp_inq_set_th_handler(struct sctp_inq *q, work_func_t callback)
225 INIT_WORK(&q->immediate, callback);