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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* 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{
David S. Miller79af02c2005-07-08 21:47:49 -070053 INIT_LIST_HEAD(&queue->in_chunk_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -070054 queue->in_progress = NULL;
55
56 /* Create a task for delivering data. */
57 INIT_WORK(&queue->immediate, NULL, 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{
David S. Miller79af02c2005-07-08 21:47:49 -070065 struct sctp_chunk *chunk, *tmp;
Linus Torvalds1da177e2005-04-16 15:20:36 -070066
67 /* Empty the queue. */
David S. Miller79af02c2005-07-08 21:47:49 -070068 list_for_each_entry_safe(chunk, tmp, &queue->in_chunk_list, list) {
69 list_del_init(&chunk->list);
Linus Torvalds1da177e2005-04-16 15:20:36 -070070 sctp_chunk_free(chunk);
David S. Miller79af02c2005-07-08 21:47:49 -070071 }
Linus Torvalds1da177e2005-04-16 15:20:36 -070072
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
79 if (queue->malloced) {
80 /* Dump the master memory segment. */
81 kfree(queue);
82 }
83}
84
85/* Put a new packet in an SCTP inqueue.
86 * We assume that packet->sctp_hdr is set and in host byte order.
87 */
88void sctp_inq_push(struct sctp_inq *q, struct sctp_chunk *packet)
89{
90 /* Directly call the packet handling routine. */
91
92 /* We are now calling this either from the soft interrupt
93 * or from the backlog processing.
94 * Eventually, we should clean up inqueue to not rely
95 * on the BH related data structures.
96 */
David S. Miller79af02c2005-07-08 21:47:49 -070097 list_add_tail(&packet->list, &q->in_chunk_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -070098 q->immediate.func(q->immediate.data);
99}
100
101/* Extract a chunk from an SCTP inqueue.
102 *
103 * WARNING: If you need to put the chunk on another queue, you need to
104 * make a shallow copy (clone) of it.
105 */
106struct sctp_chunk *sctp_inq_pop(struct sctp_inq *queue)
107{
108 struct sctp_chunk *chunk;
109 sctp_chunkhdr_t *ch = NULL;
110
111 /* The assumption is that we are safe to process the chunks
112 * at this time.
113 */
114
115 if ((chunk = queue->in_progress)) {
116 /* There is a packet that we have been working on.
117 * Any post processing work to do before we move on?
118 */
119 if (chunk->singleton ||
120 chunk->end_of_packet ||
121 chunk->pdiscard) {
122 sctp_chunk_free(chunk);
123 chunk = queue->in_progress = NULL;
124 } else {
125 /* Nothing to do. Next chunk in the packet, please. */
126 ch = (sctp_chunkhdr_t *) chunk->chunk_end;
127
128 /* Force chunk->skb->data to chunk->chunk_end. */
129 skb_pull(chunk->skb,
130 chunk->chunk_end - chunk->skb->data);
131 }
132 }
133
134 /* Do we need to take the next packet out of the queue to process? */
135 if (!chunk) {
David S. Miller79af02c2005-07-08 21:47:49 -0700136 struct list_head *entry;
137
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138 /* Is the queue empty? */
David S. Miller79af02c2005-07-08 21:47:49 -0700139 if (list_empty(&queue->in_chunk_list))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140 return NULL;
141
David S. Miller79af02c2005-07-08 21:47:49 -0700142 entry = queue->in_chunk_list.next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143 chunk = queue->in_progress =
David S. Miller79af02c2005-07-08 21:47:49 -0700144 list_entry(entry, struct sctp_chunk, list);
145 list_del_init(entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146
147 /* This is the first chunk in the packet. */
148 chunk->singleton = 1;
149 ch = (sctp_chunkhdr_t *) chunk->skb->data;
150 }
151
152 chunk->chunk_hdr = ch;
153 chunk->chunk_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
154 /* In the unlikely case of an IP reassembly, the skb could be
155 * non-linear. If so, update chunk_end so that it doesn't go past
156 * the skb->tail.
157 */
158 if (unlikely(skb_is_nonlinear(chunk->skb))) {
159 if (chunk->chunk_end > chunk->skb->tail)
160 chunk->chunk_end = chunk->skb->tail;
161 }
162 skb_pull(chunk->skb, sizeof(sctp_chunkhdr_t));
163 chunk->subh.v = NULL; /* Subheader is no longer valid. */
164
165 if (chunk->chunk_end < chunk->skb->tail) {
166 /* This is not a singleton */
167 chunk->singleton = 0;
168 } else if (chunk->chunk_end > chunk->skb->tail) {
169 /* RFC 2960, Section 6.10 Bundling
170 *
171 * Partial chunks MUST NOT be placed in an SCTP packet.
172 * If the receiver detects a partial chunk, it MUST drop
173 * the chunk.
174 *
175 * Since the end of the chunk is past the end of our buffer
176 * (which contains the whole packet, we can freely discard
177 * the whole packet.
178 */
179 sctp_chunk_free(chunk);
180 chunk = queue->in_progress = NULL;
181
182 return NULL;
183 } else {
184 /* We are at the end of the packet, so mark the chunk
185 * in case we need to send a SACK.
186 */
187 chunk->end_of_packet = 1;
188 }
189
190 SCTP_DEBUG_PRINTK("+++sctp_inq_pop+++ chunk %p[%s],"
191 " length %d, skb->len %d\n",chunk,
192 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)),
193 ntohs(chunk->chunk_hdr->length), chunk->skb->len);
194 return chunk;
195}
196
197/* Set a top-half handler.
198 *
199 * Originally, we the top-half handler was scheduled as a BH. We now
200 * call the handler directly in sctp_inq_push() at a time that
201 * we know we are lock safe.
202 * The intent is that this routine will pull stuff out of the
203 * inqueue and process it.
204 */
205void sctp_inq_set_th_handler(struct sctp_inq *q,
206 void (*callback)(void *), void *arg)
207{
208 INIT_WORK(&q->immediate, callback, arg);
209}
210