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 static void afs_free_addrlist(struct rcu_head *rcu)
17 {
18 struct afs_addr_list *alist = container_of(rcu, struct afs_addr_list, rcu);
19 unsigned int i;
20
21 for (i = 0; i < alist->nr_addrs; i++)
22 rxrpc_kernel_put_peer(alist->addrs[i].peer);
23 trace_afs_alist(alist->debug_id, refcount_read(&alist->usage), afs_alist_trace_free);
24 kfree(alist);
25 }
26
27 /*
28 * Release an address list.
29 */
30 void afs_put_addrlist(struct afs_addr_list *alist, enum afs_alist_trace reason)
31 {
32 unsigned int debug_id;
33 bool dead;
34 int r;
35
36 if (!alist)
37 return;
38 debug_id = alist->debug_id;
39 dead = __refcount_dec_and_test(&alist->usage, &r);
40 trace_afs_alist(debug_id, r - 1, reason);
41 if (dead)
42 call_rcu(&alist->rcu, afs_free_addrlist);
43 }
44
45 struct afs_addr_list *afs_get_addrlist(struct afs_addr_list *alist, enum afs_alist_trace reason)
46 {
47 int r;
48
49 if (alist) {
50 __refcount_inc(&alist->usage, &r);
51 trace_afs_alist(alist->debug_id, r + 1, reason);
52 }
53 return alist;
54 }
55
56 /*
57 * Allocate an address list.
58 */
59 struct afs_addr_list *afs_alloc_addrlist(unsigned int nr)
60 {
61 struct afs_addr_list *alist;
62 static atomic_t debug_id;
63
64 _enter("%u", nr);
65
66 if (nr > AFS_MAX_ADDRESSES)
67 nr = AFS_MAX_ADDRESSES;
68
69 alist = kzalloc(struct_size(alist, addrs, nr), GFP_KERNEL);
70 if (!alist)
71 return NULL;
72
73 refcount_set(&alist->usage, 1);
74 alist->max_addrs = nr;
75 alist->debug_id = atomic_inc_return(&debug_id);
76 trace_afs_alist(alist->debug_id, 1, afs_alist_trace_alloc);
77 return alist;
78 }
79
80 /*
81 * Parse a text string consisting of delimited addresses.
82 */
83 struct afs_vlserver_list *afs_parse_text_addrs(struct afs_net *net,
84 const char *text, size_t len,
85 char delim,
86 unsigned short service,
87 unsigned short port)
88 {
89 struct afs_vlserver_list *vllist;
90 struct afs_addr_list *alist;
91 const char *p, *end = text + len;
92 const char *problem;
93 unsigned int nr = 0;
94 int ret = -ENOMEM;
95
96 _enter("%*.*s,%c", (int)len, (int)len, text, delim);
97
98 if (!len) {
99 _leave(" = -EDESTADDRREQ [empty]");
100 return ERR_PTR(-EDESTADDRREQ);
101 }
102
103 if (delim == ':' && (memchr(text, ',', len) || !memchr(text, '.', len)))
104 delim = ',';
105
106 /* Count the addresses */
107 p = text;
108 do {
109 if (!*p) {
110 problem = "nul";
111 goto inval;
112 }
113 if (*p == delim)
114 continue;
115 nr++;
116 if (*p == '[') {
117 p++;
118 if (p == end) {
119 problem = "brace1";
120 goto inval;
121 }
122 p = memchr(p, ']', end - p);
123 if (!p) {
124 problem = "brace2";
125 goto inval;
126 }
127 p++;
128 if (p >= end)
129 break;
130 }
131
132 p = memchr(p, delim, end - p);
133 if (!p)
134 break;
135 p++;
136 } while (p < end);
137
138 _debug("%u/%u addresses", nr, AFS_MAX_ADDRESSES);
139
140 vllist = afs_alloc_vlserver_list(1);
141 if (!vllist)
142 return ERR_PTR(-ENOMEM);
143
144 vllist->nr_servers = 1;
145 vllist->servers[0].server = afs_alloc_vlserver("<dummy>", 7, AFS_VL_PORT);
146 if (!vllist->servers[0].server)
147 goto error_vl;
148
149 alist = afs_alloc_addrlist(nr);
150 if (!alist)
151 goto error;
152
153 /* Extract the addresses */
154 p = text;
155 do {
156 const char *q, *stop;
157 unsigned int xport = port;
158 __be32 x[4];
159 int family;
160
161 if (*p == delim) {
162 p++;
163 continue;
164 }
165
166 if (*p == '[') {
167 p++;
168 q = memchr(p, ']', end - p);
169 } else {
170 for (q = p; q < end; q++)
171 if (*q == '+' || *q == delim)
172 break;
173 }
174
175 if (in4_pton(p, q - p, (u8 *)&x[0], -1, &stop)) {
176 family = AF_INET;
177 } else if (in6_pton(p, q - p, (u8 *)x, -1, &stop)) {
178 family = AF_INET6;
179 } else {
180 problem = "family";
181 goto bad_address;
182 }
183
184 p = q;
185 if (stop != p) {
186 problem = "nostop";
187 goto bad_address;
188 }
189
190 if (q < end && *q == ']')
191 p++;
192
193 if (p < end) {
194 if (*p == '+') {
195 /* Port number specification "+1234" */
196 xport = 0;
197 p++;
198 if (p >= end || !isdigit(*p)) {
199 problem = "port";
200 goto bad_address;
201 }
202 do {
203 xport *= 10;
204 xport += *p - '';
205 if (xport > 65535) {
206 problem = "pval";
207 goto bad_address;
208 }
209 p++;
210 } while (p < end && isdigit(*p));
211 } else if (*p == delim) {
212 p++;
213 } else {
214 problem = "weird";
215 goto bad_address;
216 }
217 }
218
219 if (family == AF_INET)
220 ret = afs_merge_fs_addr4(net, alist, x[0], xport);
221 else
222 ret = afs_merge_fs_addr6(net, alist, x, xport);
223 if (ret < 0)
224 goto error;
225
226 } while (p < end);
227
228 rcu_assign_pointer(vllist->servers[0].server->addresses, alist);
229 _leave(" = [nr %u]", alist->nr_addrs);
230 return vllist;
231
232 inval:
233 _leave(" = -EINVAL [%s %zu %*.*s]",
234 problem, p - text, (int)len, (int)len, text);
235 return ERR_PTR(-EINVAL);
236 bad_address:
237 _leave(" = -EINVAL [%s %zu %*.*s]",
238 problem, p - text, (int)len, (int)len, text);
239 ret = -EINVAL;
240 error:
241 afs_put_addrlist(alist, afs_alist_trace_put_parse_error);
242 error_vl:
243 afs_put_vlserverlist(net, vllist);
244 return ERR_PTR(ret);
245 }
246
247 /*
248 * Perform a DNS query for VL servers and build a up an address list.
249 */
250 struct afs_vlserver_list *afs_dns_query(struct afs_cell *cell, time64_t *_expiry)
251 {
252 struct afs_vlserver_list *vllist;
253 char *result = NULL;
254 int ret;
255
256 _enter("%s", cell->name);
257
258 ret = dns_query(cell->net->net, "afsdb", cell->name, cell->name_len,
259 "srv=1", &result, _expiry, true);
260 if (ret < 0) {
261 _leave(" = %d [dns]", ret);
262 return ERR_PTR(ret);
263 }
264
265 if (*_expiry == 0)
266 *_expiry = ktime_get_real_seconds() + 60;
267
268 if (ret > 1 && result[0] == 0)
269 vllist = afs_extract_vlserver_list(cell, result, ret);
270 else
271 vllist = afs_parse_text_addrs(cell->net, result, ret, ',',
272 VL_SERVICE, AFS_VL_PORT);
273 kfree(result);
274 if (IS_ERR(vllist) && vllist != ERR_PTR(-ENOMEM))
275 pr_err("Failed to parse DNS data %ld\n", PTR_ERR(vllist));
276
277 return vllist;
278 }
279
280 /*
281 * Merge an IPv4 entry into a fileserver address list.
282 */
283 int afs_merge_fs_addr4(struct afs_net *net, struct afs_addr_list *alist,
284 __be32 xdr, u16 port)
285 {
286 struct sockaddr_rxrpc srx;
287 struct rxrpc_peer *peer;
288 int i;
289
290 if (alist->nr_addrs >= alist->max_addrs)
291 return 0;
292
293 srx.srx_family = AF_RXRPC;
294 srx.transport_type = SOCK_DGRAM;
295 srx.transport_len = sizeof(srx.transport.sin);
296 srx.transport.sin.sin_family = AF_INET;
297 srx.transport.sin.sin_port = htons(port);
298 srx.transport.sin.sin_addr.s_addr = xdr;
299
300 peer = rxrpc_kernel_lookup_peer(net->socket, &srx, GFP_KERNEL);
301 if (!peer)
302 return -ENOMEM;
303
304 for (i = 0; i < alist->nr_ipv4; i++) {
305 if (peer == alist->addrs[i].peer) {
306 rxrpc_kernel_put_peer(peer);
307 return 0;
308 }
309 if (peer <= alist->addrs[i].peer)
310 break;
311 }
312
313 if (i < alist->nr_addrs)
314 memmove(alist->addrs + i + 1,
315 alist->addrs + i,
316 sizeof(alist->addrs[0]) * (alist->nr_addrs - i));
317
318 alist->addrs[i].peer = peer;
319 alist->nr_ipv4++;
320 alist->nr_addrs++;
321 return 0;
322 }
323
324 /*
325 * Merge an IPv6 entry into a fileserver address list.
326 */
327 int afs_merge_fs_addr6(struct afs_net *net, struct afs_addr_list *alist,
328 __be32 *xdr, u16 port)
329 {
330 struct sockaddr_rxrpc srx;
331 struct rxrpc_peer *peer;
332 int i;
333
334 if (alist->nr_addrs >= alist->max_addrs)
335 return 0;
336
337 srx.srx_family = AF_RXRPC;
338 srx.transport_type = SOCK_DGRAM;
339 srx.transport_len = sizeof(srx.transport.sin6);
340 srx.transport.sin6.sin6_family = AF_INET6;
341 srx.transport.sin6.sin6_port = htons(port);
342 memcpy(&srx.transport.sin6.sin6_addr, xdr, 16);
343
344 peer = rxrpc_kernel_lookup_peer(net->socket, &srx, GFP_KERNEL);
345 if (!peer)
346 return -ENOMEM;
347
348 for (i = alist->nr_ipv4; i < alist->nr_addrs; i++) {
349 if (peer == alist->addrs[i].peer) {
350 rxrpc_kernel_put_peer(peer);
351 return 0;
352 }
353 if (peer <= alist->addrs[i].peer)
354 break;
355 }
356
357 if (i < alist->nr_addrs)
358 memmove(alist->addrs + i + 1,
359 alist->addrs + i,
360 sizeof(alist->addrs[0]) * (alist->nr_addrs - i));
361 alist->addrs[i].peer = peer;
362 alist->nr_addrs++;
363 return 0;
364 }
365
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