sctp: do not clear chunk->ecn_ce_done flag
[cascardo/linux.git] / net / sctp / inqueue.c
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                 if (chunk->head_skb) {
221                         struct sctp_input_cb
222                                 *cb = SCTP_INPUT_CB(chunk->skb),
223                                 *head_cb = SCTP_INPUT_CB(chunk->head_skb);
224
225                         cb->chunk = head_cb->chunk;
226                         cb->af = head_cb->af;
227                 }
228         }
229
230         chunk->chunk_hdr = ch;
231         chunk->chunk_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
232         skb_pull(chunk->skb, sizeof(sctp_chunkhdr_t));
233         chunk->subh.v = NULL; /* Subheader is no longer valid.  */
234
235         if (chunk->chunk_end + sizeof(sctp_chunkhdr_t) <
236             skb_tail_pointer(chunk->skb)) {
237                 /* This is not a singleton */
238                 chunk->singleton = 0;
239         } else if (chunk->chunk_end > skb_tail_pointer(chunk->skb)) {
240                 /* Discard inside state machine. */
241                 chunk->pdiscard = 1;
242                 chunk->chunk_end = skb_tail_pointer(chunk->skb);
243         } else {
244                 /* We are at the end of the packet, so mark the chunk
245                  * in case we need to send a SACK.
246                  */
247                 chunk->end_of_packet = 1;
248         }
249
250         pr_debug("+++sctp_inq_pop+++ chunk:%p[%s], length:%d, skb->len:%d\n",
251                  chunk, sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)),
252                  ntohs(chunk->chunk_hdr->length), chunk->skb->len);
253
254         return chunk;
255 }
256
257 /* Set a top-half handler.
258  *
259  * Originally, we the top-half handler was scheduled as a BH.  We now
260  * call the handler directly in sctp_inq_push() at a time that
261  * we know we are lock safe.
262  * The intent is that this routine will pull stuff out of the
263  * inqueue and process it.
264  */
265 void sctp_inq_set_th_handler(struct sctp_inq *q, work_func_t callback)
266 {
267         INIT_WORK(&q->immediate, callback);
268 }