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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; | |
e6a7d7f7 | 16 | static atomic_t debug_ids; |
0a5143f2 DH |
17 | |
18 | vlserver = kzalloc(struct_size(vlserver, name, name_len + 1), | |
19 | GFP_KERNEL); | |
20 | if (vlserver) { | |
c56f9ec8 | 21 | refcount_set(&vlserver->ref, 1); |
0a5143f2 | 22 | rwlock_init(&vlserver->lock); |
3bf0fb6f DH |
23 | init_waitqueue_head(&vlserver->probe_wq); |
24 | spin_lock_init(&vlserver->probe_lock); | |
e6a7d7f7 | 25 | vlserver->debug_id = atomic_inc_return(&debug_ids); |
b95b3094 | 26 | vlserver->rtt = UINT_MAX; |
0a5143f2 | 27 | vlserver->name_len = name_len; |
e38f299e | 28 | vlserver->service_id = VL_SERVICE; |
0a5143f2 DH |
29 | vlserver->port = port; |
30 | memcpy(vlserver->name, name, name_len); | |
31 | } | |
32 | return vlserver; | |
33 | } | |
34 | ||
35 | static void afs_vlserver_rcu(struct rcu_head *rcu) | |
36 | { | |
37 | struct afs_vlserver *vlserver = container_of(rcu, struct afs_vlserver, rcu); | |
38 | ||
1e5d8493 DH |
39 | afs_put_addrlist(rcu_access_pointer(vlserver->addresses), |
40 | afs_alist_trace_put_vlserver); | |
0a5143f2 DH |
41 | kfree_rcu(vlserver, rcu); |
42 | } | |
43 | ||
44 | void afs_put_vlserver(struct afs_net *net, struct afs_vlserver *vlserver) | |
45 | { | |
c56f9ec8 DH |
46 | if (vlserver && |
47 | refcount_dec_and_test(&vlserver->ref)) | |
48 | call_rcu(&vlserver->rcu, afs_vlserver_rcu); | |
0a5143f2 DH |
49 | } |
50 | ||
51 | struct afs_vlserver_list *afs_alloc_vlserver_list(unsigned int nr_servers) | |
52 | { | |
53 | struct afs_vlserver_list *vllist; | |
54 | ||
55 | vllist = kzalloc(struct_size(vllist, servers, nr_servers), GFP_KERNEL); | |
56 | if (vllist) { | |
c56f9ec8 | 57 | refcount_set(&vllist->ref, 1); |
0a5143f2 DH |
58 | rwlock_init(&vllist->lock); |
59 | } | |
60 | ||
61 | return vllist; | |
62 | } | |
63 | ||
64 | void afs_put_vlserverlist(struct afs_net *net, struct afs_vlserver_list *vllist) | |
65 | { | |
66 | if (vllist) { | |
c56f9ec8 | 67 | if (refcount_dec_and_test(&vllist->ref)) { |
0a5143f2 DH |
68 | int i; |
69 | ||
70 | for (i = 0; i < vllist->nr_servers; i++) { | |
71 | afs_put_vlserver(net, vllist->servers[i].server); | |
72 | } | |
73 | kfree_rcu(vllist, rcu); | |
74 | } | |
75 | } | |
76 | } | |
77 | ||
78 | static u16 afs_extract_le16(const u8 **_b) | |
79 | { | |
80 | u16 val; | |
81 | ||
82 | val = (u16)*(*_b)++ << 0; | |
83 | val |= (u16)*(*_b)++ << 8; | |
84 | return val; | |
85 | } | |
86 | ||
87 | /* | |
88 | * Build a VL server address list from a DNS queried server list. | |
89 | */ | |
72904d7b DH |
90 | static struct afs_addr_list *afs_extract_vl_addrs(struct afs_net *net, |
91 | const u8 **_b, const u8 *end, | |
0a5143f2 DH |
92 | u8 nr_addrs, u16 port) |
93 | { | |
94 | struct afs_addr_list *alist; | |
95 | const u8 *b = *_b; | |
96 | int ret = -EINVAL; | |
97 | ||
e38f299e | 98 | alist = afs_alloc_addrlist(nr_addrs); |
0a5143f2 DH |
99 | if (!alist) |
100 | return ERR_PTR(-ENOMEM); | |
101 | if (nr_addrs == 0) | |
102 | return alist; | |
103 | ||
104 | for (; nr_addrs > 0 && end - b >= nr_addrs; nr_addrs--) { | |
105 | struct dns_server_list_v1_address hdr; | |
106 | __be32 x[4]; | |
107 | ||
108 | hdr.address_type = *b++; | |
109 | ||
110 | switch (hdr.address_type) { | |
111 | case DNS_ADDRESS_IS_IPV4: | |
112 | if (end - b < 4) { | |
113 | _leave(" = -EINVAL [short inet]"); | |
114 | goto error; | |
115 | } | |
116 | memcpy(x, b, 4); | |
72904d7b DH |
117 | ret = afs_merge_fs_addr4(net, alist, x[0], port); |
118 | if (ret < 0) | |
119 | goto error; | |
0a5143f2 DH |
120 | b += 4; |
121 | break; | |
122 | ||
123 | case DNS_ADDRESS_IS_IPV6: | |
124 | if (end - b < 16) { | |
125 | _leave(" = -EINVAL [short inet6]"); | |
126 | goto error; | |
127 | } | |
128 | memcpy(x, b, 16); | |
72904d7b DH |
129 | ret = afs_merge_fs_addr6(net, alist, x, port); |
130 | if (ret < 0) | |
131 | goto error; | |
0a5143f2 DH |
132 | b += 16; |
133 | break; | |
134 | ||
135 | default: | |
136 | _leave(" = -EADDRNOTAVAIL [unknown af %u]", | |
137 | hdr.address_type); | |
138 | ret = -EADDRNOTAVAIL; | |
139 | goto error; | |
140 | } | |
141 | } | |
142 | ||
143 | /* Start with IPv6 if available. */ | |
144 | if (alist->nr_ipv4 < alist->nr_addrs) | |
3bf0fb6f | 145 | alist->preferred = alist->nr_ipv4; |
0a5143f2 DH |
146 | |
147 | *_b = b; | |
148 | return alist; | |
149 | ||
150 | error: | |
151 | *_b = b; | |
1e5d8493 | 152 | afs_put_addrlist(alist, afs_alist_trace_put_parse_error); |
0a5143f2 DH |
153 | return ERR_PTR(ret); |
154 | } | |
155 | ||
156 | /* | |
157 | * Build a VL server list from a DNS queried server list. | |
158 | */ | |
159 | struct afs_vlserver_list *afs_extract_vlserver_list(struct afs_cell *cell, | |
160 | const void *buffer, | |
161 | size_t buffer_size) | |
162 | { | |
163 | const struct dns_server_list_v1_header *hdr = buffer; | |
164 | struct dns_server_list_v1_server bs; | |
165 | struct afs_vlserver_list *vllist, *previous; | |
166 | struct afs_addr_list *addrs; | |
167 | struct afs_vlserver *server; | |
168 | const u8 *b = buffer, *end = buffer + buffer_size; | |
169 | int ret = -ENOMEM, nr_servers, i, j; | |
170 | ||
171 | _enter(""); | |
172 | ||
173 | /* Check that it's a server list, v1 */ | |
174 | if (end - b < sizeof(*hdr) || | |
175 | hdr->hdr.content != DNS_PAYLOAD_IS_SERVER_LIST || | |
176 | hdr->hdr.version != 1) { | |
177 | pr_notice("kAFS: Got DNS record [%u,%u] len %zu\n", | |
178 | hdr->hdr.content, hdr->hdr.version, end - b); | |
179 | ret = -EDESTADDRREQ; | |
180 | goto dump; | |
181 | } | |
182 | ||
183 | nr_servers = hdr->nr_servers; | |
184 | ||
185 | vllist = afs_alloc_vlserver_list(nr_servers); | |
186 | if (!vllist) | |
187 | return ERR_PTR(-ENOMEM); | |
188 | ||
189 | vllist->source = (hdr->source < NR__dns_record_source) ? | |
190 | hdr->source : NR__dns_record_source; | |
191 | vllist->status = (hdr->status < NR__dns_lookup_status) ? | |
192 | hdr->status : NR__dns_lookup_status; | |
193 | ||
194 | read_lock(&cell->vl_servers_lock); | |
195 | previous = afs_get_vlserverlist( | |
196 | rcu_dereference_protected(cell->vl_servers, | |
197 | lockdep_is_held(&cell->vl_servers_lock))); | |
198 | read_unlock(&cell->vl_servers_lock); | |
199 | ||
200 | b += sizeof(*hdr); | |
201 | while (end - b >= sizeof(bs)) { | |
202 | bs.name_len = afs_extract_le16(&b); | |
203 | bs.priority = afs_extract_le16(&b); | |
204 | bs.weight = afs_extract_le16(&b); | |
205 | bs.port = afs_extract_le16(&b); | |
206 | bs.source = *b++; | |
207 | bs.status = *b++; | |
208 | bs.protocol = *b++; | |
209 | bs.nr_addrs = *b++; | |
210 | ||
211 | _debug("extract %u %u %u %u %u %u %*.*s", | |
212 | bs.name_len, bs.priority, bs.weight, | |
213 | bs.port, bs.protocol, bs.nr_addrs, | |
214 | bs.name_len, bs.name_len, b); | |
215 | ||
216 | if (end - b < bs.name_len) | |
217 | break; | |
218 | ||
219 | ret = -EPROTONOSUPPORT; | |
220 | if (bs.protocol == DNS_SERVER_PROTOCOL_UNSPECIFIED) { | |
221 | bs.protocol = DNS_SERVER_PROTOCOL_UDP; | |
222 | } else if (bs.protocol != DNS_SERVER_PROTOCOL_UDP) { | |
223 | _leave(" = [proto %u]", bs.protocol); | |
224 | goto error; | |
225 | } | |
226 | ||
227 | if (bs.port == 0) | |
228 | bs.port = AFS_VL_PORT; | |
229 | if (bs.source > NR__dns_record_source) | |
230 | bs.source = NR__dns_record_source; | |
231 | if (bs.status > NR__dns_lookup_status) | |
232 | bs.status = NR__dns_lookup_status; | |
233 | ||
ca1cbbdc | 234 | /* See if we can update an old server record */ |
0a5143f2 | 235 | server = NULL; |
ca1cbbdc DH |
236 | for (i = 0; i < previous->nr_servers; i++) { |
237 | struct afs_vlserver *p = previous->servers[i].server; | |
238 | ||
239 | if (p->name_len == bs.name_len && | |
240 | p->port == bs.port && | |
241 | strncasecmp(b, p->name, bs.name_len) == 0) { | |
242 | server = afs_get_vlserver(p); | |
243 | break; | |
0a5143f2 DH |
244 | } |
245 | } | |
246 | ||
247 | if (!server) { | |
248 | ret = -ENOMEM; | |
249 | server = afs_alloc_vlserver(b, bs.name_len, bs.port); | |
250 | if (!server) | |
251 | goto error; | |
252 | } | |
253 | ||
254 | b += bs.name_len; | |
255 | ||
256 | /* Extract the addresses - note that we can't skip this as we | |
257 | * have to advance the payload pointer. | |
258 | */ | |
72904d7b | 259 | addrs = afs_extract_vl_addrs(cell->net, &b, end, bs.nr_addrs, bs.port); |
0a5143f2 DH |
260 | if (IS_ERR(addrs)) { |
261 | ret = PTR_ERR(addrs); | |
262 | goto error_2; | |
263 | } | |
264 | ||
265 | if (vllist->nr_servers >= nr_servers) { | |
266 | _debug("skip %u >= %u", vllist->nr_servers, nr_servers); | |
1e5d8493 | 267 | afs_put_addrlist(addrs, afs_alist_trace_put_parse_empty); |
0a5143f2 DH |
268 | afs_put_vlserver(cell->net, server); |
269 | continue; | |
270 | } | |
271 | ||
272 | addrs->source = bs.source; | |
273 | addrs->status = bs.status; | |
274 | ||
275 | if (addrs->nr_addrs == 0) { | |
1e5d8493 | 276 | afs_put_addrlist(addrs, afs_alist_trace_put_parse_empty); |
0a5143f2 DH |
277 | if (!rcu_access_pointer(server->addresses)) { |
278 | afs_put_vlserver(cell->net, server); | |
279 | continue; | |
280 | } | |
281 | } else { | |
282 | struct afs_addr_list *old = addrs; | |
283 | ||
284 | write_lock(&server->lock); | |
62860da7 PM |
285 | old = rcu_replace_pointer(server->addresses, old, |
286 | lockdep_is_held(&server->lock)); | |
0a5143f2 | 287 | write_unlock(&server->lock); |
1e5d8493 | 288 | afs_put_addrlist(old, afs_alist_trace_put_vlserver_old); |
0a5143f2 DH |
289 | } |
290 | ||
291 | ||
292 | /* TODO: Might want to check for duplicates */ | |
293 | ||
294 | /* Insertion-sort by priority and weight */ | |
295 | for (j = 0; j < vllist->nr_servers; j++) { | |
296 | if (bs.priority < vllist->servers[j].priority) | |
297 | break; /* Lower preferable */ | |
298 | if (bs.priority == vllist->servers[j].priority && | |
299 | bs.weight > vllist->servers[j].weight) | |
300 | break; /* Higher preferable */ | |
301 | } | |
302 | ||
303 | if (j < vllist->nr_servers) { | |
304 | memmove(vllist->servers + j + 1, | |
305 | vllist->servers + j, | |
306 | (vllist->nr_servers - j) * sizeof(struct afs_vlserver_entry)); | |
307 | } | |
308 | ||
3bf0fb6f DH |
309 | clear_bit(AFS_VLSERVER_FL_PROBED, &server->flags); |
310 | ||
0a5143f2 DH |
311 | vllist->servers[j].priority = bs.priority; |
312 | vllist->servers[j].weight = bs.weight; | |
313 | vllist->servers[j].server = server; | |
314 | vllist->nr_servers++; | |
315 | } | |
316 | ||
317 | if (b != end) { | |
318 | _debug("parse error %zd", b - end); | |
319 | goto error; | |
320 | } | |
321 | ||
322 | afs_put_vlserverlist(cell->net, previous); | |
323 | _leave(" = ok [%u]", vllist->nr_servers); | |
324 | return vllist; | |
325 | ||
326 | error_2: | |
327 | afs_put_vlserver(cell->net, server); | |
328 | error: | |
329 | afs_put_vlserverlist(cell->net, vllist); | |
330 | afs_put_vlserverlist(cell->net, previous); | |
331 | dump: | |
332 | if (ret != -ENOMEM) { | |
333 | printk(KERN_DEBUG "DNS: at %zu\n", (const void *)b - buffer); | |
334 | print_hex_dump_bytes("DNS: ", DUMP_PREFIX_NONE, buffer, buffer_size); | |
335 | } | |
336 | return ERR_PTR(ret); | |
337 | } |