[linux.git] / fs / afs / vl_list.c

// SPDX-License-Identifier: GPL-2.0-or-later
/* AFS vlserver list management.
 *
 * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells ([email protected])
 */

#include <linux/kernel.h>
#include <linux/slab.h>
#include "internal.h"

struct afs_vlserver *afs_alloc_vlserver(const char *name, size_t name_len,
					unsigned short port)
{
	struct afs_vlserver *vlserver;

	vlserver = kzalloc(struct_size(vlserver, name, name_len + 1),
			   GFP_KERNEL);
	if (vlserver) {
		atomic_set(&vlserver->usage, 1);
		rwlock_init(&vlserver->lock);
		init_waitqueue_head(&vlserver->probe_wq);
		spin_lock_init(&vlserver->probe_lock);
		vlserver->rtt = UINT_MAX;
		vlserver->name_len = name_len;
		vlserver->port = port;
		memcpy(vlserver->name, name, name_len);
	}
	return vlserver;
}

static void afs_vlserver_rcu(struct rcu_head *rcu)
{
	struct afs_vlserver *vlserver = container_of(rcu, struct afs_vlserver, rcu);

	afs_put_addrlist(rcu_access_pointer(vlserver->addresses));
	kfree_rcu(vlserver, rcu);
}

void afs_put_vlserver(struct afs_net *net, struct afs_vlserver *vlserver)
{
	if (vlserver) {
		unsigned int u = atomic_dec_return(&vlserver->usage);
		//_debug("VL PUT %p{%u}", vlserver, u);

		if (u == 0)
			call_rcu(&vlserver->rcu, afs_vlserver_rcu);
	}
}

struct afs_vlserver_list *afs_alloc_vlserver_list(unsigned int nr_servers)
{
	struct afs_vlserver_list *vllist;

	vllist = kzalloc(struct_size(vllist, servers, nr_servers), GFP_KERNEL);
	if (vllist) {
		atomic_set(&vllist->usage, 1);
		rwlock_init(&vllist->lock);
	}

	return vllist;
}

void afs_put_vlserverlist(struct afs_net *net, struct afs_vlserver_list *vllist)
{
	if (vllist) {
		unsigned int u = atomic_dec_return(&vllist->usage);

		//_debug("VLLS PUT %p{%u}", vllist, u);
		if (u == 0) {
			int i;

			for (i = 0; i < vllist->nr_servers; i++) {
				afs_put_vlserver(net, vllist->servers[i].server);
			}
			kfree_rcu(vllist, rcu);
		}
	}
}

static u16 afs_extract_le16(const u8 **_b)
{
	u16 val;

	val  = (u16)*(*_b)++ << 0;
	val |= (u16)*(*_b)++ << 8;
	return val;
}

/*
 * Build a VL server address list from a DNS queried server list.
 */
static struct afs_addr_list *afs_extract_vl_addrs(const u8 **_b, const u8 *end,
						  u8 nr_addrs, u16 port)
{
	struct afs_addr_list *alist;
	const u8 *b = *_b;
	int ret = -EINVAL;

	alist = afs_alloc_addrlist(nr_addrs, VL_SERVICE, port);
	if (!alist)
		return ERR_PTR(-ENOMEM);
	if (nr_addrs == 0)
		return alist;

	for (; nr_addrs > 0 && end - b >= nr_addrs; nr_addrs--) {
		struct dns_server_list_v1_address hdr;
		__be32 x[4];

		hdr.address_type = *b++;

		switch (hdr.address_type) {
		case DNS_ADDRESS_IS_IPV4:
			if (end - b < 4) {
				_leave(" = -EINVAL [short inet]");
				goto error;
			}
			memcpy(x, b, 4);
			afs_merge_fs_addr4(alist, x[0], port);
			b += 4;
			break;

		case DNS_ADDRESS_IS_IPV6:
			if (end - b < 16) {
				_leave(" = -EINVAL [short inet6]");
				goto error;
			}
			memcpy(x, b, 16);
			afs_merge_fs_addr6(alist, x, port);
			b += 16;
			break;

		default:
			_leave(" = -EADDRNOTAVAIL [unknown af %u]",
			       hdr.address_type);
			ret = -EADDRNOTAVAIL;
			goto error;
		}
	}

	/* Start with IPv6 if available. */
	if (alist->nr_ipv4 < alist->nr_addrs)
		alist->preferred = alist->nr_ipv4;

	*_b = b;
	return alist;

error:
	*_b = b;
	afs_put_addrlist(alist);
	return ERR_PTR(ret);
}

/*
 * Build a VL server list from a DNS queried server list.
 */
struct afs_vlserver_list *afs_extract_vlserver_list(struct afs_cell *cell,
						    const void *buffer,
						    size_t buffer_size)
{
	const struct dns_server_list_v1_header *hdr = buffer;
	struct dns_server_list_v1_server bs;
	struct afs_vlserver_list *vllist, *previous;
	struct afs_addr_list *addrs;
	struct afs_vlserver *server;
	const u8 *b = buffer, *end = buffer + buffer_size;
	int ret = -ENOMEM, nr_servers, i, j;

	_enter("");

	/* Check that it's a server list, v1 */
	if (end - b < sizeof(*hdr) ||
	    hdr->hdr.content != DNS_PAYLOAD_IS_SERVER_LIST ||
	    hdr->hdr.version != 1) {
		pr_notice("kAFS: Got DNS record [%u,%u] len %zu\n",
			  hdr->hdr.content, hdr->hdr.version, end - b);
		ret = -EDESTADDRREQ;
		goto dump;
	}

	nr_servers = hdr->nr_servers;

	vllist = afs_alloc_vlserver_list(nr_servers);
	if (!vllist)
		return ERR_PTR(-ENOMEM);

	vllist->source = (hdr->source < NR__dns_record_source) ?
		hdr->source : NR__dns_record_source;
	vllist->status = (hdr->status < NR__dns_lookup_status) ?
		hdr->status : NR__dns_lookup_status;

	read_lock(&cell->vl_servers_lock);
	previous = afs_get_vlserverlist(
		rcu_dereference_protected(cell->vl_servers,
					  lockdep_is_held(&cell->vl_servers_lock)));
	read_unlock(&cell->vl_servers_lock);

	b += sizeof(*hdr);
	while (end - b >= sizeof(bs)) {
		bs.name_len	= afs_extract_le16(&b);
		bs.priority	= afs_extract_le16(&b);
		bs.weight	= afs_extract_le16(&b);
		bs.port		= afs_extract_le16(&b);
		bs.source	= *b++;
		bs.status	= *b++;
		bs.protocol	= *b++;
		bs.nr_addrs	= *b++;

		_debug("extract %u %u %u %u %u %u %*.*s",
		       bs.name_len, bs.priority, bs.weight,
		       bs.port, bs.protocol, bs.nr_addrs,
		       bs.name_len, bs.name_len, b);

		if (end - b < bs.name_len)
			break;

		ret = -EPROTONOSUPPORT;
		if (bs.protocol == DNS_SERVER_PROTOCOL_UNSPECIFIED) {
			bs.protocol = DNS_SERVER_PROTOCOL_UDP;
		} else if (bs.protocol != DNS_SERVER_PROTOCOL_UDP) {
			_leave(" = [proto %u]", bs.protocol);
			goto error;
		}

		if (bs.port == 0)
			bs.port = AFS_VL_PORT;
		if (bs.source > NR__dns_record_source)
			bs.source = NR__dns_record_source;
		if (bs.status > NR__dns_lookup_status)
			bs.status = NR__dns_lookup_status;

		/* See if we can update an old server record */
		server = NULL;
		for (i = 0; i < previous->nr_servers; i++) {
			struct afs_vlserver *p = previous->servers[i].server;

			if (p->name_len == bs.name_len &&
			    p->port == bs.port &&
			    strncasecmp(b, p->name, bs.name_len) == 0) {
				server = afs_get_vlserver(p);
				break;
			}
		}

		if (!server) {
			ret = -ENOMEM;
			server = afs_alloc_vlserver(b, bs.name_len, bs.port);
			if (!server)
				goto error;
		}

		b += bs.name_len;

		/* Extract the addresses - note that we can't skip this as we
		 * have to advance the payload pointer.
		 */
		addrs = afs_extract_vl_addrs(&b, end, bs.nr_addrs, bs.port);
		if (IS_ERR(addrs)) {
			ret = PTR_ERR(addrs);
			goto error_2;
		}

		if (vllist->nr_servers >= nr_servers) {
			_debug("skip %u >= %u", vllist->nr_servers, nr_servers);
			afs_put_addrlist(addrs);
			afs_put_vlserver(cell->net, server);
			continue;
		}

		addrs->source = bs.source;
		addrs->status = bs.status;

		if (addrs->nr_addrs == 0) {
			afs_put_addrlist(addrs);
			if (!rcu_access_pointer(server->addresses)) {
				afs_put_vlserver(cell->net, server);
				continue;
			}
		} else {
			struct afs_addr_list *old = addrs;

			write_lock(&server->lock);
			old = rcu_replace_pointer(server->addresses, old,
						  lockdep_is_held(&server->lock));
			write_unlock(&server->lock);
			afs_put_addrlist(old);
		}


		/* TODO: Might want to check for duplicates */

		/* Insertion-sort by priority and weight */
		for (j = 0; j < vllist->nr_servers; j++) {
			if (bs.priority < vllist->servers[j].priority)
				break; /* Lower preferable */
			if (bs.priority == vllist->servers[j].priority &&
			    bs.weight > vllist->servers[j].weight)
				break; /* Higher preferable */
		}

		if (j < vllist->nr_servers) {
			memmove(vllist->servers + j + 1,
				vllist->servers + j,
				(vllist->nr_servers - j) * sizeof(struct afs_vlserver_entry));
		}

		clear_bit(AFS_VLSERVER_FL_PROBED, &server->flags);

		vllist->servers[j].priority = bs.priority;
		vllist->servers[j].weight = bs.weight;
		vllist->servers[j].server = server;
		vllist->nr_servers++;
	}

	if (b != end) {
		_debug("parse error %zd", b - end);
		goto error;
	}

	afs_put_vlserverlist(cell->net, previous);
	_leave(" = ok [%u]", vllist->nr_servers);
	return vllist;

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