1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* Server address list management |
3 | * |
4 | * Copyright (C) 2017 Red Hat, Inc. All Rights Reserved. |
5 | * Written by David Howells (dhowells@redhat.com) |
6 | */ |
7 | |
8 | #include <linux/slab.h> |
9 | #include <linux/ctype.h> |
10 | #include <linux/dns_resolver.h> |
11 | #include <linux/inet.h> |
12 | #include <keys/rxrpc-type.h> |
13 | #include "internal.h" |
14 | #include "afs_fs.h" |
15 | |
16 | /* |
17 | * Release an address list. |
18 | */ |
19 | void afs_put_addrlist(struct afs_addr_list *alist) |
20 | { |
21 | if (alist && refcount_dec_and_test(r: &alist->usage)) |
22 | kfree_rcu(alist, rcu); |
23 | } |
24 | |
25 | /* |
26 | * Allocate an address list. |
27 | */ |
28 | struct afs_addr_list *afs_alloc_addrlist(unsigned int nr, |
29 | unsigned short service, |
30 | unsigned short port) |
31 | { |
32 | struct afs_addr_list *alist; |
33 | unsigned int i; |
34 | |
35 | _enter("%u,%u,%u" , nr, service, port); |
36 | |
37 | if (nr > AFS_MAX_ADDRESSES) |
38 | nr = AFS_MAX_ADDRESSES; |
39 | |
40 | alist = kzalloc(struct_size(alist, addrs, nr), GFP_KERNEL); |
41 | if (!alist) |
42 | return NULL; |
43 | |
44 | refcount_set(r: &alist->usage, n: 1); |
45 | alist->max_addrs = nr; |
46 | |
47 | for (i = 0; i < nr; i++) { |
48 | struct sockaddr_rxrpc *srx = &alist->addrs[i]; |
49 | srx->srx_family = AF_RXRPC; |
50 | srx->srx_service = service; |
51 | srx->transport_type = SOCK_DGRAM; |
52 | srx->transport_len = sizeof(srx->transport.sin6); |
53 | srx->transport.sin6.sin6_family = AF_INET6; |
54 | srx->transport.sin6.sin6_port = htons(port); |
55 | } |
56 | |
57 | return alist; |
58 | } |
59 | |
60 | /* |
61 | * Parse a text string consisting of delimited addresses. |
62 | */ |
63 | struct afs_vlserver_list *afs_parse_text_addrs(struct afs_net *net, |
64 | const char *text, size_t len, |
65 | char delim, |
66 | unsigned short service, |
67 | unsigned short port) |
68 | { |
69 | struct afs_vlserver_list *vllist; |
70 | struct afs_addr_list *alist; |
71 | const char *p, *end = text + len; |
72 | const char *problem; |
73 | unsigned int nr = 0; |
74 | int ret = -ENOMEM; |
75 | |
76 | _enter("%*.*s,%c" , (int)len, (int)len, text, delim); |
77 | |
78 | if (!len) { |
79 | _leave(" = -EDESTADDRREQ [empty]" ); |
80 | return ERR_PTR(error: -EDESTADDRREQ); |
81 | } |
82 | |
83 | if (delim == ':' && (memchr(p: text, c: ',', size: len) || !memchr(p: text, c: '.', size: len))) |
84 | delim = ','; |
85 | |
86 | /* Count the addresses */ |
87 | p = text; |
88 | do { |
89 | if (!*p) { |
90 | problem = "nul" ; |
91 | goto inval; |
92 | } |
93 | if (*p == delim) |
94 | continue; |
95 | nr++; |
96 | if (*p == '[') { |
97 | p++; |
98 | if (p == end) { |
99 | problem = "brace1" ; |
100 | goto inval; |
101 | } |
102 | p = memchr(p, c: ']', size: end - p); |
103 | if (!p) { |
104 | problem = "brace2" ; |
105 | goto inval; |
106 | } |
107 | p++; |
108 | if (p >= end) |
109 | break; |
110 | } |
111 | |
112 | p = memchr(p, c: delim, size: end - p); |
113 | if (!p) |
114 | break; |
115 | p++; |
116 | } while (p < end); |
117 | |
118 | _debug("%u/%u addresses" , nr, AFS_MAX_ADDRESSES); |
119 | |
120 | vllist = afs_alloc_vlserver_list(1); |
121 | if (!vllist) |
122 | return ERR_PTR(error: -ENOMEM); |
123 | |
124 | vllist->nr_servers = 1; |
125 | vllist->servers[0].server = afs_alloc_vlserver("<dummy>" , 7, AFS_VL_PORT); |
126 | if (!vllist->servers[0].server) |
127 | goto error_vl; |
128 | |
129 | alist = afs_alloc_addrlist(nr, service, AFS_VL_PORT); |
130 | if (!alist) |
131 | goto error; |
132 | |
133 | /* Extract the addresses */ |
134 | p = text; |
135 | do { |
136 | const char *q, *stop; |
137 | unsigned int xport = port; |
138 | __be32 x[4]; |
139 | int family; |
140 | |
141 | if (*p == delim) { |
142 | p++; |
143 | continue; |
144 | } |
145 | |
146 | if (*p == '[') { |
147 | p++; |
148 | q = memchr(p, c: ']', size: end - p); |
149 | } else { |
150 | for (q = p; q < end; q++) |
151 | if (*q == '+' || *q == delim) |
152 | break; |
153 | } |
154 | |
155 | if (in4_pton(src: p, srclen: q - p, dst: (u8 *)&x[0], delim: -1, end: &stop)) { |
156 | family = AF_INET; |
157 | } else if (in6_pton(src: p, srclen: q - p, dst: (u8 *)x, delim: -1, end: &stop)) { |
158 | family = AF_INET6; |
159 | } else { |
160 | problem = "family" ; |
161 | goto bad_address; |
162 | } |
163 | |
164 | p = q; |
165 | if (stop != p) { |
166 | problem = "nostop" ; |
167 | goto bad_address; |
168 | } |
169 | |
170 | if (q < end && *q == ']') |
171 | p++; |
172 | |
173 | if (p < end) { |
174 | if (*p == '+') { |
175 | /* Port number specification "+1234" */ |
176 | xport = 0; |
177 | p++; |
178 | if (p >= end || !isdigit(c: *p)) { |
179 | problem = "port" ; |
180 | goto bad_address; |
181 | } |
182 | do { |
183 | xport *= 10; |
184 | xport += *p - '0'; |
185 | if (xport > 65535) { |
186 | problem = "pval" ; |
187 | goto bad_address; |
188 | } |
189 | p++; |
190 | } while (p < end && isdigit(c: *p)); |
191 | } else if (*p == delim) { |
192 | p++; |
193 | } else { |
194 | problem = "weird" ; |
195 | goto bad_address; |
196 | } |
197 | } |
198 | |
199 | if (family == AF_INET) |
200 | afs_merge_fs_addr4(alist, x[0], xport); |
201 | else |
202 | afs_merge_fs_addr6(alist, x, xport); |
203 | |
204 | } while (p < end); |
205 | |
206 | rcu_assign_pointer(vllist->servers[0].server->addresses, alist); |
207 | _leave(" = [nr %u]" , alist->nr_addrs); |
208 | return vllist; |
209 | |
210 | inval: |
211 | _leave(" = -EINVAL [%s %zu %*.*s]" , |
212 | problem, p - text, (int)len, (int)len, text); |
213 | return ERR_PTR(error: -EINVAL); |
214 | bad_address: |
215 | _leave(" = -EINVAL [%s %zu %*.*s]" , |
216 | problem, p - text, (int)len, (int)len, text); |
217 | ret = -EINVAL; |
218 | error: |
219 | afs_put_addrlist(alist); |
220 | error_vl: |
221 | afs_put_vlserverlist(net, vllist); |
222 | return ERR_PTR(error: ret); |
223 | } |
224 | |
225 | /* |
226 | * Compare old and new address lists to see if there's been any change. |
227 | * - How to do this in better than O(Nlog(N)) time? |
228 | * - We don't really want to sort the address list, but would rather take the |
229 | * list as we got it so as not to undo record rotation by the DNS server. |
230 | */ |
231 | #if 0 |
232 | static int afs_cmp_addr_list(const struct afs_addr_list *a1, |
233 | const struct afs_addr_list *a2) |
234 | { |
235 | } |
236 | #endif |
237 | |
238 | /* |
239 | * Perform a DNS query for VL servers and build a up an address list. |
240 | */ |
241 | struct afs_vlserver_list *afs_dns_query(struct afs_cell *cell, time64_t *_expiry) |
242 | { |
243 | struct afs_vlserver_list *vllist; |
244 | char *result = NULL; |
245 | int ret; |
246 | |
247 | _enter("%s" , cell->name); |
248 | |
249 | ret = dns_query(net: cell->net->net, type: "afsdb" , name: cell->name, namelen: cell->name_len, |
250 | options: "srv=1" , result: &result, _expiry, invalidate: true); |
251 | if (ret < 0) { |
252 | _leave(" = %d [dns]" , ret); |
253 | return ERR_PTR(error: ret); |
254 | } |
255 | |
256 | if (*_expiry == 0) |
257 | *_expiry = ktime_get_real_seconds() + 60; |
258 | |
259 | if (ret > 1 && result[0] == 0) |
260 | vllist = afs_extract_vlserver_list(cell, result, ret); |
261 | else |
262 | vllist = afs_parse_text_addrs(net: cell->net, text: result, len: ret, delim: ',', |
263 | VL_SERVICE, AFS_VL_PORT); |
264 | kfree(objp: result); |
265 | if (IS_ERR(ptr: vllist) && vllist != ERR_PTR(error: -ENOMEM)) |
266 | pr_err("Failed to parse DNS data %ld\n" , PTR_ERR(vllist)); |
267 | |
268 | return vllist; |
269 | } |
270 | |
271 | /* |
272 | * Merge an IPv4 entry into a fileserver address list. |
273 | */ |
274 | void afs_merge_fs_addr4(struct afs_addr_list *alist, __be32 xdr, u16 port) |
275 | { |
276 | struct sockaddr_rxrpc *srx; |
277 | u32 addr = ntohl(xdr); |
278 | int i; |
279 | |
280 | if (alist->nr_addrs >= alist->max_addrs) |
281 | return; |
282 | |
283 | for (i = 0; i < alist->nr_ipv4; i++) { |
284 | struct sockaddr_in *a = &alist->addrs[i].transport.sin; |
285 | u32 a_addr = ntohl(a->sin_addr.s_addr); |
286 | u16 a_port = ntohs(a->sin_port); |
287 | |
288 | if (addr == a_addr && port == a_port) |
289 | return; |
290 | if (addr == a_addr && port < a_port) |
291 | break; |
292 | if (addr < a_addr) |
293 | break; |
294 | } |
295 | |
296 | if (i < alist->nr_addrs) |
297 | memmove(alist->addrs + i + 1, |
298 | alist->addrs + i, |
299 | sizeof(alist->addrs[0]) * (alist->nr_addrs - i)); |
300 | |
301 | srx = &alist->addrs[i]; |
302 | srx->srx_family = AF_RXRPC; |
303 | srx->transport_type = SOCK_DGRAM; |
304 | srx->transport_len = sizeof(srx->transport.sin); |
305 | srx->transport.sin.sin_family = AF_INET; |
306 | srx->transport.sin.sin_port = htons(port); |
307 | srx->transport.sin.sin_addr.s_addr = xdr; |
308 | alist->nr_ipv4++; |
309 | alist->nr_addrs++; |
310 | } |
311 | |
312 | /* |
313 | * Merge an IPv6 entry into a fileserver address list. |
314 | */ |
315 | void afs_merge_fs_addr6(struct afs_addr_list *alist, __be32 *xdr, u16 port) |
316 | { |
317 | struct sockaddr_rxrpc *srx; |
318 | int i, diff; |
319 | |
320 | if (alist->nr_addrs >= alist->max_addrs) |
321 | return; |
322 | |
323 | for (i = alist->nr_ipv4; i < alist->nr_addrs; i++) { |
324 | struct sockaddr_in6 *a = &alist->addrs[i].transport.sin6; |
325 | u16 a_port = ntohs(a->sin6_port); |
326 | |
327 | diff = memcmp(p: xdr, q: &a->sin6_addr, size: 16); |
328 | if (diff == 0 && port == a_port) |
329 | return; |
330 | if (diff == 0 && port < a_port) |
331 | break; |
332 | if (diff < 0) |
333 | break; |
334 | } |
335 | |
336 | if (i < alist->nr_addrs) |
337 | memmove(alist->addrs + i + 1, |
338 | alist->addrs + i, |
339 | sizeof(alist->addrs[0]) * (alist->nr_addrs - i)); |
340 | |
341 | srx = &alist->addrs[i]; |
342 | srx->srx_family = AF_RXRPC; |
343 | srx->transport_type = SOCK_DGRAM; |
344 | srx->transport_len = sizeof(srx->transport.sin6); |
345 | srx->transport.sin6.sin6_family = AF_INET6; |
346 | srx->transport.sin6.sin6_port = htons(port); |
347 | memcpy(&srx->transport.sin6.sin6_addr, xdr, 16); |
348 | alist->nr_addrs++; |
349 | } |
350 | |
351 | /* |
352 | * Get an address to try. |
353 | */ |
354 | bool afs_iterate_addresses(struct afs_addr_cursor *ac) |
355 | { |
356 | unsigned long set, failed; |
357 | int index; |
358 | |
359 | if (!ac->alist) |
360 | return false; |
361 | |
362 | set = ac->alist->responded; |
363 | failed = ac->alist->failed; |
364 | _enter("%lx-%lx-%lx,%d" , set, failed, ac->tried, ac->index); |
365 | |
366 | ac->nr_iterations++; |
367 | |
368 | set &= ~(failed | ac->tried); |
369 | |
370 | if (!set) |
371 | return false; |
372 | |
373 | index = READ_ONCE(ac->alist->preferred); |
374 | if (test_bit(index, &set)) |
375 | goto selected; |
376 | |
377 | index = __ffs(set); |
378 | |
379 | selected: |
380 | ac->index = index; |
381 | set_bit(nr: index, addr: &ac->tried); |
382 | ac->responded = false; |
383 | return true; |
384 | } |
385 | |
386 | /* |
387 | * Release an address list cursor. |
388 | */ |
389 | int afs_end_cursor(struct afs_addr_cursor *ac) |
390 | { |
391 | struct afs_addr_list *alist; |
392 | |
393 | alist = ac->alist; |
394 | if (alist) { |
395 | if (ac->responded && |
396 | ac->index != alist->preferred && |
397 | test_bit(ac->alist->preferred, &ac->tried)) |
398 | WRITE_ONCE(alist->preferred, ac->index); |
399 | afs_put_addrlist(alist); |
400 | ac->alist = NULL; |
401 | } |
402 | |
403 | return ac->error; |
404 | } |
405 | |