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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
16static 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(peer: alist->addrs[i].peer);
23 trace_afs_alist(alist_debug_id: alist->debug_id, ref: refcount_read(r: &alist->usage), reason: afs_alist_trace_free);
24 kfree(objp: alist);
25}
26
27/*
28 * Release an address list.
29 */
30void 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(r: &alist->usage, oldp: &r);
40 trace_afs_alist(alist_debug_id: debug_id, ref: r - 1, reason);
41 if (dead)
42 call_rcu(head: &alist->rcu, func: afs_free_addrlist);
43}
44
45struct 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(r: &alist->usage, oldp: &r);
51 trace_afs_alist(alist_debug_id: alist->debug_id, ref: r + 1, reason);
52 }
53 return alist;
54}
55
56/*
57 * Allocate an address list.
58 */
59struct 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(r: &alist->usage, n: 1);
74 alist->max_addrs = nr;
75 alist->debug_id = atomic_inc_return(v: &debug_id);
76 trace_afs_alist(alist_debug_id: alist->debug_id, ref: 1, reason: afs_alist_trace_alloc);
77 return alist;
78}
79
80/*
81 * Parse a text string consisting of delimited addresses.
82 */
83struct 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(error: -EDESTADDRREQ);
101 }
102
103 if (delim == ':' && (memchr(p: text, c: ',', size: len) || !memchr(p: text, c: '.', size: 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, c: ']', size: 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, c: delim, size: 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(error: -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, c: ']', size: end - p);
169 } else {
170 for (q = p; q < end; q++)
171 if (*q == '+' || *q == delim)
172 break;
173 }
174
175 if (in4_pton(src: p, srclen: q - p, dst: (u8 *)&x[0], delim: -1, end: &stop)) {
176 family = AF_INET;
177 } else if (in6_pton(src: p, srclen: q - p, dst: (u8 *)x, delim: -1, end: &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(c: *p)) {
199 problem = "port";
200 goto bad_address;
201 }
202 do {
203 xport *= 10;
204 xport += *p - '0';
205 if (xport > 65535) {
206 problem = "pval";
207 goto bad_address;
208 }
209 p++;
210 } while (p < end && isdigit(c: *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, addr: alist, xdr: x[0], port: xport);
221 else
222 ret = afs_merge_fs_addr6(net, addr: alist, xdr: x, port: 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
232inval:
233 _leave(" = -EINVAL [%s %zu %*.*s]",
234 problem, p - text, (int)len, (int)len, text);
235 return ERR_PTR(error: -EINVAL);
236bad_address:
237 _leave(" = -EINVAL [%s %zu %*.*s]",
238 problem, p - text, (int)len, (int)len, text);
239 ret = -EINVAL;
240error:
241 afs_put_addrlist(alist, reason: afs_alist_trace_put_parse_error);
242error_vl:
243 afs_put_vlserverlist(net, vllist);
244 return ERR_PTR(error: ret);
245}
246
247/*
248 * Perform a DNS query for VL servers and build a up an address list.
249 */
250struct 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(net: cell->net->net, type: "afsdb", name: cell->name, namelen: cell->name_len,
259 options: "srv=1", result: &result, _expiry, invalidate: true);
260 if (ret < 0) {
261 _leave(" = %d [dns]", ret);
262 return ERR_PTR(error: 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(net: cell->net, text: result, len: ret, delim: ',',
272 VL_SERVICE, AFS_VL_PORT);
273 kfree(objp: result);
274 if (IS_ERR(ptr: vllist) && vllist != ERR_PTR(error: -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 */
283int 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(sock: net->socket, srx: &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 */
327int 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(sock: net->socket, srx: &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
366/*
367 * Set the app data on the rxrpc peers an address list points to
368 */
369void afs_set_peer_appdata(struct afs_server *server,
370 struct afs_addr_list *old_alist,
371 struct afs_addr_list *new_alist)
372{
373 unsigned long data = (unsigned long)server;
374 int n = 0, o = 0;
375
376 if (!old_alist) {
377 /* New server. Just set all. */
378 for (; n < new_alist->nr_addrs; n++)
379 rxrpc_kernel_set_peer_data(peer: new_alist->addrs[n].peer, app_data: data);
380 return;
381 }
382 if (!new_alist) {
383 /* Dead server. Just remove all. */
384 for (; o < old_alist->nr_addrs; o++)
385 rxrpc_kernel_set_peer_data(peer: old_alist->addrs[o].peer, app_data: 0);
386 return;
387 }
388
389 /* Walk through the two lists simultaneously, setting new peers and
390 * clearing old ones. The two lists are ordered by pointer to peer
391 * record.
392 */
393 while (n < new_alist->nr_addrs && o < old_alist->nr_addrs) {
394 struct rxrpc_peer *pn = new_alist->addrs[n].peer;
395 struct rxrpc_peer *po = old_alist->addrs[o].peer;
396
397 if (pn == po)
398 continue;
399 if (pn < po) {
400 rxrpc_kernel_set_peer_data(peer: pn, app_data: data);
401 n++;
402 } else {
403 rxrpc_kernel_set_peer_data(peer: po, app_data: 0);
404 o++;
405 }
406 }
407
408 if (n < new_alist->nr_addrs)
409 for (; n < new_alist->nr_addrs; n++)
410 rxrpc_kernel_set_peer_data(peer: new_alist->addrs[n].peer, app_data: data);
411 if (o < old_alist->nr_addrs)
412 for (; o < old_alist->nr_addrs; o++)
413 rxrpc_kernel_set_peer_data(peer: old_alist->addrs[o].peer, app_data: 0);
414}
415

source code of linux/fs/afs/addr_list.c