1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* SCTP kernel implementation |
3 | * (C) Copyright IBM Corp. 2003, 2004 |
4 | * |
5 | * This file is part of the SCTP kernel implementation |
6 | * |
7 | * This file contains the code relating the chunk abstraction. |
8 | * |
9 | * Please send any bug reports or fixes you make to the |
10 | * email address(es): |
11 | * lksctp developers <linux-sctp@vger.kernel.org> |
12 | * |
13 | * Written or modified by: |
14 | * Jon Grimm <jgrimm@us.ibm.com> |
15 | * Sridhar Samudrala <sri@us.ibm.com> |
16 | */ |
17 | |
18 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
19 | |
20 | #include <linux/types.h> |
21 | #include <linux/kernel.h> |
22 | #include <linux/net.h> |
23 | #include <linux/inet.h> |
24 | #include <linux/skbuff.h> |
25 | #include <linux/slab.h> |
26 | #include <net/sock.h> |
27 | #include <net/sctp/sctp.h> |
28 | #include <net/sctp/sm.h> |
29 | |
30 | /* This file is mostly in anticipation of future work, but initially |
31 | * populate with fragment tracking for an outbound message. |
32 | */ |
33 | |
34 | /* Initialize datamsg from memory. */ |
35 | static void sctp_datamsg_init(struct sctp_datamsg *msg) |
36 | { |
37 | refcount_set(r: &msg->refcnt, n: 1); |
38 | msg->send_failed = 0; |
39 | msg->send_error = 0; |
40 | msg->can_delay = 1; |
41 | msg->abandoned = 0; |
42 | msg->expires_at = 0; |
43 | INIT_LIST_HEAD(list: &msg->chunks); |
44 | } |
45 | |
46 | /* Allocate and initialize datamsg. */ |
47 | static struct sctp_datamsg *sctp_datamsg_new(gfp_t gfp) |
48 | { |
49 | struct sctp_datamsg *msg; |
50 | msg = kmalloc(size: sizeof(struct sctp_datamsg), flags: gfp); |
51 | if (msg) { |
52 | sctp_datamsg_init(msg); |
53 | SCTP_DBG_OBJCNT_INC(datamsg); |
54 | } |
55 | return msg; |
56 | } |
57 | |
58 | void sctp_datamsg_free(struct sctp_datamsg *msg) |
59 | { |
60 | struct sctp_chunk *chunk; |
61 | |
62 | /* This doesn't have to be a _safe vairant because |
63 | * sctp_chunk_free() only drops the refs. |
64 | */ |
65 | list_for_each_entry(chunk, &msg->chunks, frag_list) |
66 | sctp_chunk_free(chunk); |
67 | |
68 | sctp_datamsg_put(msg); |
69 | } |
70 | |
71 | /* Final destructruction of datamsg memory. */ |
72 | static void sctp_datamsg_destroy(struct sctp_datamsg *msg) |
73 | { |
74 | struct sctp_association *asoc = NULL; |
75 | struct list_head *pos, *temp; |
76 | struct sctp_chunk *chunk; |
77 | struct sctp_ulpevent *ev; |
78 | int error, sent; |
79 | |
80 | /* Release all references. */ |
81 | list_for_each_safe(pos, temp, &msg->chunks) { |
82 | list_del_init(entry: pos); |
83 | chunk = list_entry(pos, struct sctp_chunk, frag_list); |
84 | |
85 | if (!msg->send_failed) { |
86 | sctp_chunk_put(chunk); |
87 | continue; |
88 | } |
89 | |
90 | asoc = chunk->asoc; |
91 | error = msg->send_error ?: asoc->outqueue.error; |
92 | sent = chunk->has_tsn ? SCTP_DATA_SENT : SCTP_DATA_UNSENT; |
93 | |
94 | if (sctp_ulpevent_type_enabled(subscribe: asoc->subscribe, |
95 | SCTP_SEND_FAILED)) { |
96 | ev = sctp_ulpevent_make_send_failed(asoc, chunk, flags: sent, |
97 | error, GFP_ATOMIC); |
98 | if (ev) |
99 | asoc->stream.si->enqueue_event(&asoc->ulpq, ev); |
100 | } |
101 | |
102 | if (sctp_ulpevent_type_enabled(subscribe: asoc->subscribe, |
103 | SCTP_SEND_FAILED_EVENT)) { |
104 | ev = sctp_ulpevent_make_send_failed_event(asoc, chunk, |
105 | flags: sent, error, |
106 | GFP_ATOMIC); |
107 | if (ev) |
108 | asoc->stream.si->enqueue_event(&asoc->ulpq, ev); |
109 | } |
110 | |
111 | sctp_chunk_put(chunk); |
112 | } |
113 | |
114 | SCTP_DBG_OBJCNT_DEC(datamsg); |
115 | kfree(objp: msg); |
116 | } |
117 | |
118 | /* Hold a reference. */ |
119 | static void sctp_datamsg_hold(struct sctp_datamsg *msg) |
120 | { |
121 | refcount_inc(r: &msg->refcnt); |
122 | } |
123 | |
124 | /* Release a reference. */ |
125 | void sctp_datamsg_put(struct sctp_datamsg *msg) |
126 | { |
127 | if (refcount_dec_and_test(r: &msg->refcnt)) |
128 | sctp_datamsg_destroy(msg); |
129 | } |
130 | |
131 | /* Assign a chunk to this datamsg. */ |
132 | static void sctp_datamsg_assign(struct sctp_datamsg *msg, struct sctp_chunk *chunk) |
133 | { |
134 | sctp_datamsg_hold(msg); |
135 | chunk->msg = msg; |
136 | } |
137 | |
138 | |
139 | /* A data chunk can have a maximum payload of (2^16 - 20). Break |
140 | * down any such message into smaller chunks. Opportunistically, fragment |
141 | * the chunks down to the current MTU constraints. We may get refragmented |
142 | * later if the PMTU changes, but it is _much better_ to fragment immediately |
143 | * with a reasonable guess than always doing our fragmentation on the |
144 | * soft-interrupt. |
145 | */ |
146 | struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc, |
147 | struct sctp_sndrcvinfo *sinfo, |
148 | struct iov_iter *from) |
149 | { |
150 | size_t len, first_len, max_data, remaining; |
151 | size_t msg_len = iov_iter_count(i: from); |
152 | struct sctp_shared_key *shkey = NULL; |
153 | struct list_head *pos, *temp; |
154 | struct sctp_chunk *chunk; |
155 | struct sctp_datamsg *msg; |
156 | int err; |
157 | |
158 | msg = sctp_datamsg_new(GFP_KERNEL); |
159 | if (!msg) |
160 | return ERR_PTR(error: -ENOMEM); |
161 | |
162 | /* Note: Calculate this outside of the loop, so that all fragments |
163 | * have the same expiration. |
164 | */ |
165 | if (asoc->peer.prsctp_capable && sinfo->sinfo_timetolive && |
166 | (SCTP_PR_TTL_ENABLED(sinfo->sinfo_flags) || |
167 | !SCTP_PR_POLICY(sinfo->sinfo_flags))) |
168 | msg->expires_at = jiffies + |
169 | msecs_to_jiffies(m: sinfo->sinfo_timetolive); |
170 | |
171 | /* This is the biggest possible DATA chunk that can fit into |
172 | * the packet |
173 | */ |
174 | max_data = asoc->frag_point; |
175 | if (unlikely(!max_data)) { |
176 | max_data = sctp_min_frag_point(sp: sctp_sk(sk: asoc->base.sk), |
177 | datasize: sctp_datachk_len(stream: &asoc->stream)); |
178 | pr_warn_ratelimited("%s: asoc:%p frag_point is zero, forcing max_data to default minimum (%zu)" , |
179 | __func__, asoc, max_data); |
180 | } |
181 | |
182 | /* If the peer requested that we authenticate DATA chunks |
183 | * we need to account for bundling of the AUTH chunks along with |
184 | * DATA. |
185 | */ |
186 | if (sctp_auth_send_cid(chunk: SCTP_CID_DATA, asoc)) { |
187 | struct sctp_hmac *hmac_desc = sctp_auth_asoc_get_hmac(asoc); |
188 | |
189 | if (hmac_desc) |
190 | max_data -= SCTP_PAD4(sizeof(struct sctp_auth_chunk) + |
191 | hmac_desc->hmac_len); |
192 | |
193 | if (sinfo->sinfo_tsn && |
194 | sinfo->sinfo_ssn != asoc->active_key_id) { |
195 | shkey = sctp_auth_get_shkey(asoc, key_id: sinfo->sinfo_ssn); |
196 | if (!shkey) { |
197 | err = -EINVAL; |
198 | goto errout; |
199 | } |
200 | } else { |
201 | shkey = asoc->shkey; |
202 | } |
203 | } |
204 | |
205 | /* Set first_len and then account for possible bundles on first frag */ |
206 | first_len = max_data; |
207 | |
208 | /* Check to see if we have a pending SACK and try to let it be bundled |
209 | * with this message. Do this if we don't have any data queued already. |
210 | * To check that, look at out_qlen and retransmit list. |
211 | * NOTE: we will not reduce to account for SACK, if the message would |
212 | * not have been fragmented. |
213 | */ |
214 | if (timer_pending(timer: &asoc->timers[SCTP_EVENT_TIMEOUT_SACK]) && |
215 | asoc->outqueue.out_qlen == 0 && |
216 | list_empty(head: &asoc->outqueue.retransmit) && |
217 | msg_len > max_data) |
218 | first_len -= SCTP_PAD4(sizeof(struct sctp_sack_chunk)); |
219 | |
220 | /* Encourage Cookie-ECHO bundling. */ |
221 | if (asoc->state < SCTP_STATE_COOKIE_ECHOED) |
222 | first_len -= SCTP_ARBITRARY_COOKIE_ECHO_LEN; |
223 | |
224 | /* Account for a different sized first fragment */ |
225 | if (msg_len >= first_len) { |
226 | msg->can_delay = 0; |
227 | if (msg_len > first_len) |
228 | SCTP_INC_STATS(asoc->base.net, |
229 | SCTP_MIB_FRAGUSRMSGS); |
230 | } else { |
231 | /* Which may be the only one... */ |
232 | first_len = msg_len; |
233 | } |
234 | |
235 | /* Create chunks for all DATA chunks. */ |
236 | for (remaining = msg_len; remaining; remaining -= len) { |
237 | u8 frag = SCTP_DATA_MIDDLE_FRAG; |
238 | |
239 | if (remaining == msg_len) { |
240 | /* First frag, which may also be the last */ |
241 | frag |= SCTP_DATA_FIRST_FRAG; |
242 | len = first_len; |
243 | } else { |
244 | /* Middle frags */ |
245 | len = max_data; |
246 | } |
247 | |
248 | if (len >= remaining) { |
249 | /* Last frag, which may also be the first */ |
250 | len = remaining; |
251 | frag |= SCTP_DATA_LAST_FRAG; |
252 | |
253 | /* The application requests to set the I-bit of the |
254 | * last DATA chunk of a user message when providing |
255 | * the user message to the SCTP implementation. |
256 | */ |
257 | if ((sinfo->sinfo_flags & SCTP_EOF) || |
258 | (sinfo->sinfo_flags & SCTP_SACK_IMMEDIATELY)) |
259 | frag |= SCTP_DATA_SACK_IMM; |
260 | } |
261 | |
262 | chunk = asoc->stream.si->make_datafrag(asoc, sinfo, len, frag, |
263 | GFP_KERNEL); |
264 | if (!chunk) { |
265 | err = -ENOMEM; |
266 | goto errout; |
267 | } |
268 | |
269 | err = sctp_user_addto_chunk(chunk, len, from); |
270 | if (err < 0) |
271 | goto errout_chunk_free; |
272 | |
273 | chunk->shkey = shkey; |
274 | |
275 | /* Put the chunk->skb back into the form expected by send. */ |
276 | __skb_pull(skb: chunk->skb, len: (__u8 *)chunk->chunk_hdr - |
277 | chunk->skb->data); |
278 | |
279 | sctp_datamsg_assign(msg, chunk); |
280 | list_add_tail(new: &chunk->frag_list, head: &msg->chunks); |
281 | } |
282 | |
283 | return msg; |
284 | |
285 | errout_chunk_free: |
286 | sctp_chunk_free(chunk); |
287 | |
288 | errout: |
289 | list_for_each_safe(pos, temp, &msg->chunks) { |
290 | list_del_init(entry: pos); |
291 | chunk = list_entry(pos, struct sctp_chunk, frag_list); |
292 | sctp_chunk_free(chunk); |
293 | } |
294 | sctp_datamsg_put(msg); |
295 | |
296 | return ERR_PTR(error: err); |
297 | } |
298 | |
299 | /* Check whether this message has expired. */ |
300 | int sctp_chunk_abandoned(struct sctp_chunk *chunk) |
301 | { |
302 | if (!chunk->asoc->peer.prsctp_capable) |
303 | return 0; |
304 | |
305 | if (chunk->msg->abandoned) |
306 | return 1; |
307 | |
308 | if (!chunk->has_tsn && |
309 | !(chunk->chunk_hdr->flags & SCTP_DATA_FIRST_FRAG)) |
310 | return 0; |
311 | |
312 | if (SCTP_PR_TTL_ENABLED(chunk->sinfo.sinfo_flags) && |
313 | time_after(jiffies, chunk->msg->expires_at)) { |
314 | struct sctp_stream_out *streamout = |
315 | SCTP_SO(&chunk->asoc->stream, |
316 | chunk->sinfo.sinfo_stream); |
317 | |
318 | if (chunk->sent_count) { |
319 | chunk->asoc->abandoned_sent[SCTP_PR_INDEX(TTL)]++; |
320 | streamout->ext->abandoned_sent[SCTP_PR_INDEX(TTL)]++; |
321 | } else { |
322 | chunk->asoc->abandoned_unsent[SCTP_PR_INDEX(TTL)]++; |
323 | streamout->ext->abandoned_unsent[SCTP_PR_INDEX(TTL)]++; |
324 | } |
325 | chunk->msg->abandoned = 1; |
326 | return 1; |
327 | } else if (SCTP_PR_RTX_ENABLED(chunk->sinfo.sinfo_flags) && |
328 | chunk->sent_count > chunk->sinfo.sinfo_timetolive) { |
329 | struct sctp_stream_out *streamout = |
330 | SCTP_SO(&chunk->asoc->stream, |
331 | chunk->sinfo.sinfo_stream); |
332 | |
333 | chunk->asoc->abandoned_sent[SCTP_PR_INDEX(RTX)]++; |
334 | streamout->ext->abandoned_sent[SCTP_PR_INDEX(RTX)]++; |
335 | chunk->msg->abandoned = 1; |
336 | return 1; |
337 | } else if (!SCTP_PR_POLICY(chunk->sinfo.sinfo_flags) && |
338 | chunk->msg->expires_at && |
339 | time_after(jiffies, chunk->msg->expires_at)) { |
340 | chunk->msg->abandoned = 1; |
341 | return 1; |
342 | } |
343 | /* PRIO policy is processed by sendmsg, not here */ |
344 | |
345 | return 0; |
346 | } |
347 | |
348 | /* This chunk (and consequently entire message) has failed in its sending. */ |
349 | void sctp_chunk_fail(struct sctp_chunk *chunk, int error) |
350 | { |
351 | chunk->msg->send_failed = 1; |
352 | chunk->msg->send_error = error; |
353 | } |
354 | |