Commit | Line | Data |
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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
0a5143f2 DH |
2 | /* AFS vlserver list management. |
3 | * | |
4 | * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved. | |
5 | * Written by David Howells (dhowells@redhat.com) | |
0a5143f2 DH |
6 | */ |
7 | ||
8 | #include <linux/kernel.h> | |
9 | #include <linux/slab.h> | |
10 | #include "internal.h" | |
11 | ||
12 | struct afs_vlserver *afs_alloc_vlserver(const char *name, size_t name_len, | |
13 | unsigned short port) | |
14 | { | |
15 | struct afs_vlserver *vlserver; | |
16 | ||
17 | vlserver = kzalloc(struct_size(vlserver, name, name_len + 1), | |
18 | GFP_KERNEL); | |
19 | if (vlserver) { | |
20 | atomic_set(&vlserver->usage, 1); | |
21 | rwlock_init(&vlserver->lock); | |
3bf0fb6f DH |
22 | init_waitqueue_head(&vlserver->probe_wq); |
23 | spin_lock_init(&vlserver->probe_lock); | |
0a5143f2 DH |
24 | vlserver->name_len = name_len; |
25 | vlserver->port = port; | |
26 | memcpy(vlserver->name, name, name_len); | |
27 | } | |
28 | return vlserver; | |
29 | } | |
30 | ||
31 | static void afs_vlserver_rcu(struct rcu_head *rcu) | |
32 | { | |
33 | struct afs_vlserver *vlserver = container_of(rcu, struct afs_vlserver, rcu); | |
34 | ||
35 | afs_put_addrlist(rcu_access_pointer(vlserver->addresses)); | |
36 | kfree_rcu(vlserver, rcu); | |
37 | } | |
38 | ||
39 | void afs_put_vlserver(struct afs_net *net, struct afs_vlserver *vlserver) | |
40 | { | |
41 | if (vlserver) { | |
42 | unsigned int u = atomic_dec_return(&vlserver->usage); | |
43 | //_debug("VL PUT %p{%u}", vlserver, u); | |
44 | ||
45 | if (u == 0) | |
46 | call_rcu(&vlserver->rcu, afs_vlserver_rcu); | |
47 | } | |
48 | } | |
49 | ||
50 | struct afs_vlserver_list *afs_alloc_vlserver_list(unsigned int nr_servers) | |
51 | { | |
52 | struct afs_vlserver_list *vllist; | |
53 | ||
54 | vllist = kzalloc(struct_size(vllist, servers, nr_servers), GFP_KERNEL); | |
55 | if (vllist) { | |
56 | atomic_set(&vllist->usage, 1); | |
57 | rwlock_init(&vllist->lock); | |
58 | } | |
59 | ||
60 | return vllist; | |
61 | } | |
62 | ||
63 | void afs_put_vlserverlist(struct afs_net *net, struct afs_vlserver_list *vllist) | |
64 | { | |
65 | if (vllist) { | |
66 | unsigned int u = atomic_dec_return(&vllist->usage); | |
67 | ||
68 | //_debug("VLLS PUT %p{%u}", vllist, u); | |
69 | if (u == 0) { | |
70 | int i; | |
71 | ||
72 | for (i = 0; i < vllist->nr_servers; i++) { | |
73 | afs_put_vlserver(net, vllist->servers[i].server); | |
74 | } | |
75 | kfree_rcu(vllist, rcu); | |
76 | } | |
77 | } | |
78 | } | |
79 | ||
80 | static u16 afs_extract_le16(const u8 **_b) | |
81 | { | |
82 | u16 val; | |
83 | ||
84 | val = (u16)*(*_b)++ << 0; | |
85 | val |= (u16)*(*_b)++ << 8; | |
86 | return val; | |
87 | } | |
88 | ||
89 | /* | |
90 | * Build a VL server address list from a DNS queried server list. | |
91 | */ | |
92 | static struct afs_addr_list *afs_extract_vl_addrs(const u8 **_b, const u8 *end, | |
93 | u8 nr_addrs, u16 port) | |
94 | { | |
95 | struct afs_addr_list *alist; | |
96 | const u8 *b = *_b; | |
97 | int ret = -EINVAL; | |
98 | ||
99 | alist = afs_alloc_addrlist(nr_addrs, VL_SERVICE, port); | |
100 | if (!alist) | |
101 | return ERR_PTR(-ENOMEM); | |
102 | if (nr_addrs == 0) | |
103 | return alist; | |
104 | ||
105 | for (; nr_addrs > 0 && end - b >= nr_addrs; nr_addrs--) { | |
106 | struct dns_server_list_v1_address hdr; | |
107 | __be32 x[4]; | |
108 | ||
109 | hdr.address_type = *b++; | |
110 | ||
111 | switch (hdr.address_type) { | |
112 | case DNS_ADDRESS_IS_IPV4: | |
113 | if (end - b < 4) { | |
114 | _leave(" = -EINVAL [short inet]"); | |
115 | goto error; | |
116 | } | |
117 | memcpy(x, b, 4); | |
118 | afs_merge_fs_addr4(alist, x[0], port); | |
119 | b += 4; | |
120 | break; | |
121 | ||
122 | case DNS_ADDRESS_IS_IPV6: | |
123 | if (end - b < 16) { | |
124 | _leave(" = -EINVAL [short inet6]"); | |
125 | goto error; | |
126 | } | |
127 | memcpy(x, b, 16); | |
128 | afs_merge_fs_addr6(alist, x, port); | |
129 | b += 16; | |
130 | break; | |
131 | ||
132 | default: | |
133 | _leave(" = -EADDRNOTAVAIL [unknown af %u]", | |
134 | hdr.address_type); | |
135 | ret = -EADDRNOTAVAIL; | |
136 | goto error; | |
137 | } | |
138 | } | |
139 | ||
140 | /* Start with IPv6 if available. */ | |
141 | if (alist->nr_ipv4 < alist->nr_addrs) | |
3bf0fb6f | 142 | alist->preferred = alist->nr_ipv4; |
0a5143f2 DH |
143 | |
144 | *_b = b; | |
145 | return alist; | |
146 | ||
147 | error: | |
148 | *_b = b; | |
149 | afs_put_addrlist(alist); | |
150 | return ERR_PTR(ret); | |
151 | } | |
152 | ||
153 | /* | |
154 | * Build a VL server list from a DNS queried server list. | |
155 | */ | |
156 | struct afs_vlserver_list *afs_extract_vlserver_list(struct afs_cell *cell, | |
157 | const void *buffer, | |
158 | size_t buffer_size) | |
159 | { | |
160 | const struct dns_server_list_v1_header *hdr = buffer; | |
161 | struct dns_server_list_v1_server bs; | |
162 | struct afs_vlserver_list *vllist, *previous; | |
163 | struct afs_addr_list *addrs; | |
164 | struct afs_vlserver *server; | |
165 | const u8 *b = buffer, *end = buffer + buffer_size; | |
166 | int ret = -ENOMEM, nr_servers, i, j; | |
167 | ||
168 | _enter(""); | |
169 | ||
170 | /* Check that it's a server list, v1 */ | |
171 | if (end - b < sizeof(*hdr) || | |
172 | hdr->hdr.content != DNS_PAYLOAD_IS_SERVER_LIST || | |
173 | hdr->hdr.version != 1) { | |
174 | pr_notice("kAFS: Got DNS record [%u,%u] len %zu\n", | |
175 | hdr->hdr.content, hdr->hdr.version, end - b); | |
176 | ret = -EDESTADDRREQ; | |
177 | goto dump; | |
178 | } | |
179 | ||
180 | nr_servers = hdr->nr_servers; | |
181 | ||
182 | vllist = afs_alloc_vlserver_list(nr_servers); | |
183 | if (!vllist) | |
184 | return ERR_PTR(-ENOMEM); | |
185 | ||
186 | vllist->source = (hdr->source < NR__dns_record_source) ? | |
187 | hdr->source : NR__dns_record_source; | |
188 | vllist->status = (hdr->status < NR__dns_lookup_status) ? | |
189 | hdr->status : NR__dns_lookup_status; | |
190 | ||
191 | read_lock(&cell->vl_servers_lock); | |
192 | previous = afs_get_vlserverlist( | |
193 | rcu_dereference_protected(cell->vl_servers, | |
194 | lockdep_is_held(&cell->vl_servers_lock))); | |
195 | read_unlock(&cell->vl_servers_lock); | |
196 | ||
197 | b += sizeof(*hdr); | |
198 | while (end - b >= sizeof(bs)) { | |
199 | bs.name_len = afs_extract_le16(&b); | |
200 | bs.priority = afs_extract_le16(&b); | |
201 | bs.weight = afs_extract_le16(&b); | |
202 | bs.port = afs_extract_le16(&b); | |
203 | bs.source = *b++; | |
204 | bs.status = *b++; | |
205 | bs.protocol = *b++; | |
206 | bs.nr_addrs = *b++; | |
207 | ||
208 | _debug("extract %u %u %u %u %u %u %*.*s", | |
209 | bs.name_len, bs.priority, bs.weight, | |
210 | bs.port, bs.protocol, bs.nr_addrs, | |
211 | bs.name_len, bs.name_len, b); | |
212 | ||
213 | if (end - b < bs.name_len) | |
214 | break; | |
215 | ||
216 | ret = -EPROTONOSUPPORT; | |
217 | if (bs.protocol == DNS_SERVER_PROTOCOL_UNSPECIFIED) { | |
218 | bs.protocol = DNS_SERVER_PROTOCOL_UDP; | |
219 | } else if (bs.protocol != DNS_SERVER_PROTOCOL_UDP) { | |
220 | _leave(" = [proto %u]", bs.protocol); | |
221 | goto error; | |
222 | } | |
223 | ||
224 | if (bs.port == 0) | |
225 | bs.port = AFS_VL_PORT; | |
226 | if (bs.source > NR__dns_record_source) | |
227 | bs.source = NR__dns_record_source; | |
228 | if (bs.status > NR__dns_lookup_status) | |
229 | bs.status = NR__dns_lookup_status; | |
230 | ||
ca1cbbdc | 231 | /* See if we can update an old server record */ |
0a5143f2 | 232 | server = NULL; |
ca1cbbdc DH |
233 | for (i = 0; i < previous->nr_servers; i++) { |
234 | struct afs_vlserver *p = previous->servers[i].server; | |
235 | ||
236 | if (p->name_len == bs.name_len && | |
237 | p->port == bs.port && | |
238 | strncasecmp(b, p->name, bs.name_len) == 0) { | |
239 | server = afs_get_vlserver(p); | |
240 | break; | |
0a5143f2 DH |
241 | } |
242 | } | |
243 | ||
244 | if (!server) { | |
245 | ret = -ENOMEM; | |
246 | server = afs_alloc_vlserver(b, bs.name_len, bs.port); | |
247 | if (!server) | |
248 | goto error; | |
249 | } | |
250 | ||
251 | b += bs.name_len; | |
252 | ||
253 | /* Extract the addresses - note that we can't skip this as we | |
254 | * have to advance the payload pointer. | |
255 | */ | |
256 | addrs = afs_extract_vl_addrs(&b, end, bs.nr_addrs, bs.port); | |
257 | if (IS_ERR(addrs)) { | |
258 | ret = PTR_ERR(addrs); | |
259 | goto error_2; | |
260 | } | |
261 | ||
262 | if (vllist->nr_servers >= nr_servers) { | |
263 | _debug("skip %u >= %u", vllist->nr_servers, nr_servers); | |
264 | afs_put_addrlist(addrs); | |
265 | afs_put_vlserver(cell->net, server); | |
266 | continue; | |
267 | } | |
268 | ||
269 | addrs->source = bs.source; | |
270 | addrs->status = bs.status; | |
271 | ||
272 | if (addrs->nr_addrs == 0) { | |
273 | afs_put_addrlist(addrs); | |
274 | if (!rcu_access_pointer(server->addresses)) { | |
275 | afs_put_vlserver(cell->net, server); | |
276 | continue; | |
277 | } | |
278 | } else { | |
279 | struct afs_addr_list *old = addrs; | |
280 | ||
281 | write_lock(&server->lock); | |
282 | rcu_swap_protected(server->addresses, old, | |
283 | lockdep_is_held(&server->lock)); | |
284 | write_unlock(&server->lock); | |
285 | afs_put_addrlist(old); | |
286 | } | |
287 | ||
288 | ||
289 | /* TODO: Might want to check for duplicates */ | |
290 | ||
291 | /* Insertion-sort by priority and weight */ | |
292 | for (j = 0; j < vllist->nr_servers; j++) { | |
293 | if (bs.priority < vllist->servers[j].priority) | |
294 | break; /* Lower preferable */ | |
295 | if (bs.priority == vllist->servers[j].priority && | |
296 | bs.weight > vllist->servers[j].weight) | |
297 | break; /* Higher preferable */ | |
298 | } | |
299 | ||
300 | if (j < vllist->nr_servers) { | |
301 | memmove(vllist->servers + j + 1, | |
302 | vllist->servers + j, | |
303 | (vllist->nr_servers - j) * sizeof(struct afs_vlserver_entry)); | |
304 | } | |
305 | ||
3bf0fb6f DH |
306 | clear_bit(AFS_VLSERVER_FL_PROBED, &server->flags); |
307 | ||
0a5143f2 DH |
308 | vllist->servers[j].priority = bs.priority; |
309 | vllist->servers[j].weight = bs.weight; | |
310 | vllist->servers[j].server = server; | |
311 | vllist->nr_servers++; | |
312 | } | |
313 | ||
314 | if (b != end) { | |
315 | _debug("parse error %zd", b - end); | |
316 | goto error; | |
317 | } | |
318 | ||
319 | afs_put_vlserverlist(cell->net, previous); | |
320 | _leave(" = ok [%u]", vllist->nr_servers); | |
321 | return vllist; | |
322 | ||
323 | error_2: | |
324 | afs_put_vlserver(cell->net, server); | |
325 | error: | |
326 | afs_put_vlserverlist(cell->net, vllist); | |
327 | afs_put_vlserverlist(cell->net, previous); | |
328 | dump: | |
329 | if (ret != -ENOMEM) { | |
330 | printk(KERN_DEBUG "DNS: at %zu\n", (const void *)b - buffer); | |
331 | print_hex_dump_bytes("DNS: ", DUMP_PREFIX_NONE, buffer, buffer_size); | |
332 | } | |
333 | return ERR_PTR(ret); | |
334 | } |