1 /* 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. */
sctp_inq_init(struct sctp_inq * queue)51 void sctp_inq_init(struct sctp_inq *queue)
52 {
53 skb_queue_head_init(&queue->in);
54 queue->in_progress = NULL;
55
56 /* Create a task for delivering data. */
57 INIT_LIST_HEAD(&queue->immediate.list);
58 queue->immediate.sync = 0;
59 queue->immediate.routine = NULL;
60 queue->immediate.data = NULL;
61
62 queue->malloced = 0;
63 }
64
65 /* Release the memory associated with an SCTP inqueue. */
sctp_inq_free(struct sctp_inq * queue)66 void sctp_inq_free(struct sctp_inq *queue)
67 {
68 struct sctp_chunk *chunk;
69
70 /* Empty the queue. */
71 while ((chunk = (struct sctp_chunk *) skb_dequeue(&queue->in)) != NULL)
72 sctp_chunk_free(chunk);
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
80 if (queue->malloced) {
81 /* Dump the master memory segment. */
82 kfree(queue);
83 }
84 }
85
86 /* Put a new packet in an SCTP inqueue.
87 * We assume that packet->sctp_hdr is set and in host byte order.
88 */
sctp_inq_push(struct sctp_inq * q,struct sctp_chunk * packet)89 void sctp_inq_push(struct sctp_inq *q, struct sctp_chunk *packet)
90 {
91 /* Directly call the packet handling routine. */
92
93 /* We are now calling this either from the soft interrupt
94 * or from the backlog processing.
95 * Eventually, we should clean up inqueue to not rely
96 * on the BH related data structures.
97 */
98 skb_queue_tail(&(q->in), (struct sk_buff *) packet);
99 q->immediate.routine(q->immediate.data);
100 }
101
102 /* Extract a chunk from an SCTP inqueue.
103 *
104 * WARNING: If you need to put the chunk on another queue, you need to
105 * make a shallow copy (clone) of it.
106 */
sctp_inq_pop(struct sctp_inq * queue)107 struct sctp_chunk *sctp_inq_pop(struct sctp_inq *queue)
108 {
109 struct sctp_chunk *chunk;
110 sctp_chunkhdr_t *ch = NULL;
111
112 /* The assumption is that we are safe to process the chunks
113 * at this time.
114 */
115
116 if ((chunk = queue->in_progress)) {
117 /* There is a packet that we have been working on.
118 * Any post processing work to do before we move on?
119 */
120 if (chunk->singleton ||
121 chunk->end_of_packet ||
122 chunk->pdiscard) {
123 sctp_chunk_free(chunk);
124 chunk = queue->in_progress = NULL;
125 } else {
126 /* Nothing to do. Next chunk in the packet, please. */
127 ch = (sctp_chunkhdr_t *) chunk->chunk_end;
128
129 /* Force chunk->skb->data to chunk->chunk_end. */
130 skb_pull(chunk->skb,
131 chunk->chunk_end - chunk->skb->data);
132 }
133 }
134
135 /* Do we need to take the next packet out of the queue to process? */
136 if (!chunk) {
137 /* Is the queue empty? */
138 if (skb_queue_empty(&queue->in))
139 return NULL;
140
141 chunk = queue->in_progress =
142 (struct sctp_chunk *) skb_dequeue(&queue->in);
143
144 /* This is the first chunk in the packet. */
145 chunk->singleton = 1;
146 ch = (sctp_chunkhdr_t *) chunk->skb->data;
147 }
148
149 chunk->chunk_hdr = ch;
150 chunk->chunk_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
151 /* In the unlikely case of an IP reassembly, the skb could be
152 * non-linear. If so, update chunk_end so that it doesn't go past
153 * the skb->tail.
154 */
155 if (unlikely(skb_is_nonlinear(chunk->skb))) {
156 if (chunk->chunk_end > chunk->skb->tail)
157 chunk->chunk_end = chunk->skb->tail;
158 }
159 skb_pull(chunk->skb, sizeof(sctp_chunkhdr_t));
160 chunk->subh.v = NULL; /* Subheader is no longer valid. */
161
162 if (chunk->chunk_end < chunk->skb->tail) {
163 /* This is not a singleton */
164 chunk->singleton = 0;
165 } else if (chunk->chunk_end > chunk->skb->tail) {
166 /* RFC 2960, Section 6.10 Bundling
167 *
168 * Partial chunks MUST NOT be placed in an SCTP packet.
169 * If the receiver detects a partial chunk, it MUST drop
170 * the chunk.
171 *
172 * Since the end of the chunk is past the end of our buffer
173 * (which contains the whole packet, we can freely discard
174 * the whole packet.
175 */
176 sctp_chunk_free(chunk);
177 chunk = queue->in_progress = NULL;
178
179 return NULL;
180 } else {
181 /* We are at the end of the packet, so mark the chunk
182 * in case we need to send a SACK.
183 */
184 chunk->end_of_packet = 1;
185 }
186
187 SCTP_DEBUG_PRINTK("+++sctp_inq_pop+++ chunk %p[%s],"
188 " length %d, skb->len %d\n",chunk,
189 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)),
190 ntohs(chunk->chunk_hdr->length), chunk->skb->len);
191 return chunk;
192 }
193
194 /* Set a top-half handler.
195 *
196 * Originally, we the top-half handler was scheduled as a BH. We now
197 * call the handler directly in sctp_inq_push() at a time that
198 * we know we are lock safe.
199 * The intent is that this routine will pull stuff out of the
200 * inqueue and process it.
201 */
sctp_inq_set_th_handler(struct sctp_inq * q,void (* callback)(void *),void * arg)202 void sctp_inq_set_th_handler(struct sctp_inq *q,
203 void (*callback)(void *), void *arg)
204 {
205 q->immediate.routine = callback;
206 q->immediate.data = arg;
207 }
208
209