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(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 */
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(&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
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(&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 */
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(&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 */
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(-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 - '0';
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
232inval:
233	_leave(" = -EINVAL [%s %zu %*.*s]",
234	       problem, p - text, (int)len, (int)len, text);
235	return ERR_PTR(-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, afs_alist_trace_put_parse_error);
242error_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 */
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(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 */
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(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 */
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(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