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(list: &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 | /* Properly release the chunk which is being worked on. */ |
42 | static inline void sctp_inq_chunk_free(struct sctp_chunk *chunk) |
43 | { |
44 | if (chunk->head_skb) |
45 | chunk->skb = chunk->head_skb; |
46 | sctp_chunk_free(chunk); |
47 | } |
48 | |
49 | /* Release the memory associated with an SCTP inqueue. */ |
50 | void sctp_inq_free(struct sctp_inq *queue) |
51 | { |
52 | struct sctp_chunk *chunk, *tmp; |
53 | |
54 | /* Empty the queue. */ |
55 | list_for_each_entry_safe(chunk, tmp, &queue->in_chunk_list, list) { |
56 | list_del_init(entry: &chunk->list); |
57 | sctp_chunk_free(chunk); |
58 | } |
59 | |
60 | /* If there is a packet which is currently being worked on, |
61 | * free it as well. |
62 | */ |
63 | if (queue->in_progress) { |
64 | sctp_inq_chunk_free(chunk: queue->in_progress); |
65 | queue->in_progress = NULL; |
66 | } |
67 | } |
68 | |
69 | /* Put a new packet in an SCTP inqueue. |
70 | * We assume that packet->sctp_hdr is set and in host byte order. |
71 | */ |
72 | void sctp_inq_push(struct sctp_inq *q, struct sctp_chunk *chunk) |
73 | { |
74 | /* Directly call the packet handling routine. */ |
75 | if (chunk->rcvr->dead) { |
76 | sctp_chunk_free(chunk); |
77 | return; |
78 | } |
79 | |
80 | /* We are now calling this either from the soft interrupt |
81 | * or from the backlog processing. |
82 | * Eventually, we should clean up inqueue to not rely |
83 | * on the BH related data structures. |
84 | */ |
85 | list_add_tail(new: &chunk->list, head: &q->in_chunk_list); |
86 | if (chunk->asoc) |
87 | chunk->asoc->stats.ipackets++; |
88 | q->immediate.func(&q->immediate); |
89 | } |
90 | |
91 | /* Peek at the next chunk on the inqeue. */ |
92 | struct sctp_chunkhdr *sctp_inq_peek(struct sctp_inq *queue) |
93 | { |
94 | struct sctp_chunk *chunk; |
95 | struct sctp_chunkhdr *ch = NULL; |
96 | |
97 | chunk = queue->in_progress; |
98 | /* If there is no more chunks in this packet, say so */ |
99 | if (chunk->singleton || |
100 | chunk->end_of_packet || |
101 | chunk->pdiscard) |
102 | return NULL; |
103 | |
104 | ch = (struct sctp_chunkhdr *)chunk->chunk_end; |
105 | |
106 | return ch; |
107 | } |
108 | |
109 | |
110 | /* Extract a chunk from an SCTP inqueue. |
111 | * |
112 | * WARNING: If you need to put the chunk on another queue, you need to |
113 | * make a shallow copy (clone) of it. |
114 | */ |
115 | struct sctp_chunk *sctp_inq_pop(struct sctp_inq *queue) |
116 | { |
117 | struct sctp_chunk *chunk; |
118 | struct sctp_chunkhdr *ch = NULL; |
119 | |
120 | /* The assumption is that we are safe to process the chunks |
121 | * at this time. |
122 | */ |
123 | |
124 | chunk = queue->in_progress; |
125 | if (chunk) { |
126 | /* There is a packet that we have been working on. |
127 | * Any post processing work to do before we move on? |
128 | */ |
129 | if (chunk->singleton || |
130 | chunk->end_of_packet || |
131 | chunk->pdiscard) { |
132 | if (chunk->head_skb == chunk->skb) { |
133 | chunk->skb = skb_shinfo(chunk->skb)->frag_list; |
134 | goto new_skb; |
135 | } |
136 | if (chunk->skb->next) { |
137 | chunk->skb = chunk->skb->next; |
138 | goto new_skb; |
139 | } |
140 | |
141 | sctp_inq_chunk_free(chunk); |
142 | chunk = queue->in_progress = NULL; |
143 | } else { |
144 | /* Nothing to do. Next chunk in the packet, please. */ |
145 | ch = (struct sctp_chunkhdr *)chunk->chunk_end; |
146 | /* Force chunk->skb->data to chunk->chunk_end. */ |
147 | skb_pull(skb: chunk->skb, len: chunk->chunk_end - chunk->skb->data); |
148 | /* We are guaranteed to pull a SCTP header. */ |
149 | } |
150 | } |
151 | |
152 | /* Do we need to take the next packet out of the queue to process? */ |
153 | if (!chunk) { |
154 | struct list_head *entry; |
155 | |
156 | next_chunk: |
157 | /* Is the queue empty? */ |
158 | entry = sctp_list_dequeue(list: &queue->in_chunk_list); |
159 | if (!entry) |
160 | return NULL; |
161 | |
162 | chunk = list_entry(entry, struct sctp_chunk, list); |
163 | |
164 | if (skb_is_gso(skb: chunk->skb) && skb_is_gso_sctp(skb: chunk->skb)) { |
165 | /* GSO-marked skbs but without frags, handle |
166 | * them normally |
167 | */ |
168 | if (skb_shinfo(chunk->skb)->frag_list) |
169 | chunk->head_skb = chunk->skb; |
170 | |
171 | /* skbs with "cover letter" */ |
172 | if (chunk->head_skb && chunk->skb->data_len == chunk->skb->len) |
173 | chunk->skb = skb_shinfo(chunk->skb)->frag_list; |
174 | |
175 | if (WARN_ON(!chunk->skb)) { |
176 | __SCTP_INC_STATS(dev_net(chunk->skb->dev), SCTP_MIB_IN_PKT_DISCARDS); |
177 | sctp_chunk_free(chunk); |
178 | goto next_chunk; |
179 | } |
180 | } |
181 | |
182 | if (chunk->asoc) |
183 | sock_rps_save_rxhash(sk: chunk->asoc->base.sk, skb: chunk->skb); |
184 | |
185 | queue->in_progress = chunk; |
186 | |
187 | new_skb: |
188 | /* This is the first chunk in the packet. */ |
189 | ch = (struct sctp_chunkhdr *)chunk->skb->data; |
190 | chunk->singleton = 1; |
191 | chunk->data_accepted = 0; |
192 | chunk->pdiscard = 0; |
193 | chunk->auth = 0; |
194 | chunk->has_asconf = 0; |
195 | chunk->end_of_packet = 0; |
196 | if (chunk->head_skb) { |
197 | struct sctp_input_cb |
198 | *cb = SCTP_INPUT_CB(chunk->skb), |
199 | *head_cb = SCTP_INPUT_CB(chunk->head_skb); |
200 | |
201 | cb->chunk = head_cb->chunk; |
202 | cb->af = head_cb->af; |
203 | } |
204 | } |
205 | |
206 | chunk->chunk_hdr = ch; |
207 | chunk->chunk_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length)); |
208 | skb_pull(skb: chunk->skb, len: sizeof(*ch)); |
209 | chunk->subh.v = NULL; /* Subheader is no longer valid. */ |
210 | |
211 | if (chunk->chunk_end + sizeof(*ch) <= skb_tail_pointer(skb: chunk->skb)) { |
212 | /* This is not a singleton */ |
213 | chunk->singleton = 0; |
214 | } else if (chunk->chunk_end > skb_tail_pointer(skb: chunk->skb)) { |
215 | /* Discard inside state machine. */ |
216 | chunk->pdiscard = 1; |
217 | chunk->chunk_end = skb_tail_pointer(skb: chunk->skb); |
218 | } else { |
219 | /* We are at the end of the packet, so mark the chunk |
220 | * in case we need to send a SACK. |
221 | */ |
222 | chunk->end_of_packet = 1; |
223 | } |
224 | |
225 | pr_debug("+++sctp_inq_pop+++ chunk:%p[%s], length:%d, skb->len:%d\n" , |
226 | chunk, sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)), |
227 | ntohs(chunk->chunk_hdr->length), chunk->skb->len); |
228 | |
229 | return chunk; |
230 | } |
231 | |
232 | /* Set a top-half handler. |
233 | * |
234 | * Originally, we the top-half handler was scheduled as a BH. We now |
235 | * call the handler directly in sctp_inq_push() at a time that |
236 | * we know we are lock safe. |
237 | * The intent is that this routine will pull stuff out of the |
238 | * inqueue and process it. |
239 | */ |
240 | void sctp_inq_set_th_handler(struct sctp_inq *q, work_func_t callback) |
241 | { |
242 | INIT_WORK(&q->immediate, callback); |
243 | } |
244 | |