Merge tag 'arc-5.2-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc
[sfrench/cifs-2.6.git] / net / sctp / inqueue.c
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* SCTP kernel implementation
3  * Copyright (c) 1999-2000 Cisco, Inc.
4  * Copyright (c) 1999-2001 Motorola, Inc.
5  * Copyright (c) 2002 International Business Machines, Corp.
6  *
7  * This file is part of the SCTP kernel implementation
8  *
9  * These functions are the methods for accessing the SCTP inqueue.
10  *
11  * An SCTP inqueue is a queue into which you push SCTP packets
12  * (which might be bundles or fragments of chunks) and out of which you
13  * pop SCTP whole chunks.
14  *
15  * Please send any bug reports or fixes you make to the
16  * email address(es):
17  *    lksctp developers <linux-sctp@vger.kernel.org>
18  *
19  * Written or modified by:
20  *    La Monte H.P. Yarroll <piggy@acm.org>
21  *    Karl Knutson <karl@athena.chicago.il.us>
22  */
23
24 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
25
26 #include <net/sctp/sctp.h>
27 #include <net/sctp/sm.h>
28 #include <linux/interrupt.h>
29 #include <linux/slab.h>
30
31 /* Initialize an SCTP inqueue.  */
32 void sctp_inq_init(struct sctp_inq *queue)
33 {
34         INIT_LIST_HEAD(&queue->in_chunk_list);
35         queue->in_progress = NULL;
36
37         /* Create a task for delivering data.  */
38         INIT_WORK(&queue->immediate, NULL);
39 }
40
41 /* Release the memory associated with an SCTP inqueue.  */
42 void sctp_inq_free(struct sctp_inq *queue)
43 {
44         struct sctp_chunk *chunk, *tmp;
45
46         /* Empty the queue.  */
47         list_for_each_entry_safe(chunk, tmp, &queue->in_chunk_list, list) {
48                 list_del_init(&chunk->list);
49                 sctp_chunk_free(chunk);
50         }
51
52         /* If there is a packet which is currently being worked on,
53          * free it as well.
54          */
55         if (queue->in_progress) {
56                 sctp_chunk_free(queue->in_progress);
57                 queue->in_progress = NULL;
58         }
59 }
60
61 /* Put a new packet in an SCTP inqueue.
62  * We assume that packet->sctp_hdr is set and in host byte order.
63  */
64 void sctp_inq_push(struct sctp_inq *q, struct sctp_chunk *chunk)
65 {
66         /* Directly call the packet handling routine. */
67         if (chunk->rcvr->dead) {
68                 sctp_chunk_free(chunk);
69                 return;
70         }
71
72         /* We are now calling this either from the soft interrupt
73          * or from the backlog processing.
74          * Eventually, we should clean up inqueue to not rely
75          * on the BH related data structures.
76          */
77         list_add_tail(&chunk->list, &q->in_chunk_list);
78         if (chunk->asoc)
79                 chunk->asoc->stats.ipackets++;
80         q->immediate.func(&q->immediate);
81 }
82
83 /* Peek at the next chunk on the inqeue. */
84 struct sctp_chunkhdr *sctp_inq_peek(struct sctp_inq *queue)
85 {
86         struct sctp_chunk *chunk;
87         struct sctp_chunkhdr *ch = NULL;
88
89         chunk = queue->in_progress;
90         /* If there is no more chunks in this packet, say so */
91         if (chunk->singleton ||
92             chunk->end_of_packet ||
93             chunk->pdiscard)
94                     return NULL;
95
96         ch = (struct sctp_chunkhdr *)chunk->chunk_end;
97
98         return ch;
99 }
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  */
107 struct sctp_chunk *sctp_inq_pop(struct sctp_inq *queue)
108 {
109         struct sctp_chunk *chunk;
110         struct sctp_chunkhdr *ch = NULL;
111
112         /* The assumption is that we are safe to process the chunks
113          * at this time.
114          */
115
116         chunk = queue->in_progress;
117         if (chunk) {
118                 /* There is a packet that we have been working on.
119                  * Any post processing work to do before we move on?
120                  */
121                 if (chunk->singleton ||
122                     chunk->end_of_packet ||
123                     chunk->pdiscard) {
124                         if (chunk->head_skb == chunk->skb) {
125                                 chunk->skb = skb_shinfo(chunk->skb)->frag_list;
126                                 goto new_skb;
127                         }
128                         if (chunk->skb->next) {
129                                 chunk->skb = chunk->skb->next;
130                                 goto new_skb;
131                         }
132
133                         if (chunk->head_skb)
134                                 chunk->skb = chunk->head_skb;
135                         sctp_chunk_free(chunk);
136                         chunk = queue->in_progress = NULL;
137                 } else {
138                         /* Nothing to do. Next chunk in the packet, please. */
139                         ch = (struct sctp_chunkhdr *)chunk->chunk_end;
140                         /* Force chunk->skb->data to chunk->chunk_end.  */
141                         skb_pull(chunk->skb, chunk->chunk_end - chunk->skb->data);
142                         /* We are guaranteed to pull a SCTP header. */
143                 }
144         }
145
146         /* Do we need to take the next packet out of the queue to process? */
147         if (!chunk) {
148                 struct list_head *entry;
149
150 next_chunk:
151                 /* Is the queue empty?  */
152                 entry = sctp_list_dequeue(&queue->in_chunk_list);
153                 if (!entry)
154                         return NULL;
155
156                 chunk = list_entry(entry, struct sctp_chunk, list);
157
158                 if (skb_is_gso(chunk->skb) && skb_is_gso_sctp(chunk->skb)) {
159                         /* GSO-marked skbs but without frags, handle
160                          * them normally
161                          */
162                         if (skb_shinfo(chunk->skb)->frag_list)
163                                 chunk->head_skb = chunk->skb;
164
165                         /* skbs with "cover letter" */
166                         if (chunk->head_skb && chunk->skb->data_len == chunk->skb->len)
167                                 chunk->skb = skb_shinfo(chunk->skb)->frag_list;
168
169                         if (WARN_ON(!chunk->skb)) {
170                                 __SCTP_INC_STATS(dev_net(chunk->skb->dev), SCTP_MIB_IN_PKT_DISCARDS);
171                                 sctp_chunk_free(chunk);
172                                 goto next_chunk;
173                         }
174                 }
175
176                 if (chunk->asoc)
177                         sock_rps_save_rxhash(chunk->asoc->base.sk, chunk->skb);
178
179                 queue->in_progress = chunk;
180
181 new_skb:
182                 /* This is the first chunk in the packet.  */
183                 ch = (struct sctp_chunkhdr *)chunk->skb->data;
184                 chunk->singleton = 1;
185                 chunk->data_accepted = 0;
186                 chunk->pdiscard = 0;
187                 chunk->auth = 0;
188                 chunk->has_asconf = 0;
189                 chunk->end_of_packet = 0;
190                 if (chunk->head_skb) {
191                         struct sctp_input_cb
192                                 *cb = SCTP_INPUT_CB(chunk->skb),
193                                 *head_cb = SCTP_INPUT_CB(chunk->head_skb);
194
195                         cb->chunk = head_cb->chunk;
196                         cb->af = head_cb->af;
197                 }
198         }
199
200         chunk->chunk_hdr = ch;
201         chunk->chunk_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length));
202         skb_pull(chunk->skb, sizeof(*ch));
203         chunk->subh.v = NULL; /* Subheader is no longer valid.  */
204
205         if (chunk->chunk_end + sizeof(*ch) <= skb_tail_pointer(chunk->skb)) {
206                 /* This is not a singleton */
207                 chunk->singleton = 0;
208         } else if (chunk->chunk_end > skb_tail_pointer(chunk->skb)) {
209                 /* Discard inside state machine. */
210                 chunk->pdiscard = 1;
211                 chunk->chunk_end = skb_tail_pointer(chunk->skb);
212         } else {
213                 /* We are at the end of the packet, so mark the chunk
214                  * in case we need to send a SACK.
215                  */
216                 chunk->end_of_packet = 1;
217         }
218
219         pr_debug("+++sctp_inq_pop+++ chunk:%p[%s], length:%d, skb->len:%d\n",
220                  chunk, sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)),
221                  ntohs(chunk->chunk_hdr->length), chunk->skb->len);
222
223         return chunk;
224 }
225
226 /* Set a top-half handler.
227  *
228  * Originally, we the top-half handler was scheduled as a BH.  We now
229  * call the handler directly in sctp_inq_push() at a time that
230  * we know we are lock safe.
231  * The intent is that this routine will pull stuff out of the
232  * inqueue and process it.
233  */
234 void sctp_inq_set_th_handler(struct sctp_inq *q, work_func_t callback)
235 {
236         INIT_WORK(&q->immediate, callback);
237 }