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

/* Server address list management
 *
 * Copyright (C) 2017 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells ([email protected])
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public Licence
 * as published by the Free Software Foundation; either version
 * 2 of the Licence, or (at your option) any later version.
 */

#include <linux/slab.h>
#include <linux/ctype.h>
#include <linux/dns_resolver.h>
#include <linux/inet.h>
#include <keys/rxrpc-type.h>
#include "internal.h"
#include "afs_fs.h"

/*
 * Release an address list.
 */
void afs_put_addrlist(struct afs_addr_list *alist)
{
	if (alist && refcount_dec_and_test(&alist->usage))
		call_rcu(&alist->rcu, (rcu_callback_t)kfree);
}

/*
 * Allocate an address list.
 */
struct afs_addr_list *afs_alloc_addrlist(unsigned int nr,
					 unsigned short service,
					 unsigned short port)
{
	struct afs_addr_list *alist;
	unsigned int i;

	_enter("%u,%u,%u", nr, service, port);

	if (nr > AFS_MAX_ADDRESSES)
		nr = AFS_MAX_ADDRESSES;

	alist = kzalloc(struct_size(alist, addrs, nr), GFP_KERNEL);
	if (!alist)
		return NULL;

	refcount_set(&alist->usage, 1);
	alist->max_addrs = nr;

	for (i = 0; i < nr; i++) {
		struct sockaddr_rxrpc *srx = &alist->addrs[i];
		srx->srx_family			= AF_RXRPC;
		srx->srx_service		= service;
		srx->transport_type		= SOCK_DGRAM;
		srx->transport_len		= sizeof(srx->transport.sin6);
		srx->transport.sin6.sin6_family	= AF_INET6;
		srx->transport.sin6.sin6_port	= htons(port);
	}

	return alist;
}

/*
 * Parse a text string consisting of delimited addresses.
 */
struct afs_vlserver_list *afs_parse_text_addrs(struct afs_net *net,
					       const char *text, size_t len,
					       char delim,
					       unsigned short service,
					       unsigned short port)
{
	struct afs_vlserver_list *vllist;
	struct afs_addr_list *alist;
	const char *p, *end = text + len;
	const char *problem;
	unsigned int nr = 0;
	int ret = -ENOMEM;

	_enter("%*.*s,%c", (int)len, (int)len, text, delim);

	if (!len) {
		_leave(" = -EDESTADDRREQ [empty]");
		return ERR_PTR(-EDESTADDRREQ);
	}

	if (delim == ':' && (memchr(text, ',', len) || !memchr(text, '.', len)))
		delim = ',';

	/* Count the addresses */
	p = text;
	do {
		if (!*p) {
			problem = "nul";
			goto inval;
		}
		if (*p == delim)
			continue;
		nr++;
		if (*p == '[') {
			p++;
			if (p == end) {
				problem = "brace1";
				goto inval;
			}
			p = memchr(p, ']', end - p);
			if (!p) {
				problem = "brace2";
				goto inval;
			}
			p++;
			if (p >= end)
				break;
		}

		p = memchr(p, delim, end - p);
		if (!p)
			break;
		p++;
	} while (p < end);

	_debug("%u/%u addresses", nr, AFS_MAX_ADDRESSES);

	vllist = afs_alloc_vlserver_list(1);
	if (!vllist)
		return ERR_PTR(-ENOMEM);

	vllist->nr_servers = 1;
	vllist->servers[0].server = afs_alloc_vlserver("<dummy>", 7, AFS_VL_PORT);
	if (!vllist->servers[0].server)
		goto error_vl;

	alist = afs_alloc_addrlist(nr, service, AFS_VL_PORT);
	if (!alist)
		goto error;

	/* Extract the addresses */
	p = text;
	do {
		const char *q, *stop;
		unsigned int xport = port;
		__be32 x[4];
		int family;

		if (*p == delim) {
			p++;
			continue;
		}

		if (*p == '[') {
			p++;
			q = memchr(p, ']', end - p);
		} else {
			for (q = p; q < end; q++)
				if (*q == '+' || *q == delim)
					break;
		}

		if (in4_pton(p, q - p, (u8 *)&x[0], -1, &stop)) {
			family = AF_INET;
		} else if (in6_pton(p, q - p, (u8 *)x, -1, &stop)) {
			family = AF_INET6;
		} else {
			problem = "family";
			goto bad_address;
		}

		p = q;
		if (stop != p) {
			problem = "nostop";
			goto bad_address;
		}

		if (q < end && *q == ']')
			p++;

		if (p < end) {
			if (*p == '+') {
				/* Port number specification "+1234" */
				xport = 0;
				p++;
				if (p >= end || !isdigit(*p)) {
					problem = "port";
					goto bad_address;
				}
				do {
					xport *= 10;
					xport += *p - '0';
					if (xport > 65535) {
						problem = "pval";
						goto bad_address;
					}
					p++;
				} while (p < end && isdigit(*p));
			} else if (*p == delim) {
				p++;
			} else {
				problem = "weird";
				goto bad_address;
			}
		}

		if (family == AF_INET)
			afs_merge_fs_addr4(alist, x[0], xport);
		else
			afs_merge_fs_addr6(alist, x, xport);

	} while (p < end);

	rcu_assign_pointer(vllist->servers[0].server->addresses, alist);
	_leave(" = [nr %u]", alist->nr_addrs);
	return vllist;

inval:
	_leave(" = -EINVAL [%s %zu %*.*s]",
	       problem, p - text, (int)len, (int)len, text);
	return ERR_PTR(-EINVAL);
bad_address:
	_leave(" = -EINVAL [%s %zu %*.*s]",
	       problem, p - text, (int)len, (int)len, text);
	ret = -EINVAL;
error:
	afs_put_addrlist(alist);
error_vl:
	afs_put_vlserverlist(net, vllist);
	return ERR_PTR(ret);
}

/*
 * Compare old and new address lists to see if there's been any change.
 * - How to do this in better than O(Nlog(N)) time?
 *   - We don't really want to sort the address list, but would rather take the
 *     list as we got it so as not to undo record rotation by the DNS server.
 */
#if 0
static int afs_cmp_addr_list(const struct afs_addr_list *a1,
			     const struct afs_addr_list *a2)
{
}
#endif

/*
 * Perform a DNS query for VL servers and build a up an address list.
 */
struct afs_vlserver_list *afs_dns_query(struct afs_cell *cell, time64_t *_expiry)
{
	struct afs_vlserver_list *vllist;
	char *result = NULL;
	int ret;

	_enter("%s", cell->name);

	ret = dns_query("afsdb", cell->name, cell->name_len, "srv=1",
			&result, _expiry);
	if (ret < 0) {
		_leave(" = %d [dns]", ret);
		return ERR_PTR(ret);
	}

	if (*_expiry == 0)
		*_expiry = ktime_get_real_seconds() + 60;

	if (ret > 1 && result[0] == 0)
		vllist = afs_extract_vlserver_list(cell, result, ret);
	else
		vllist = afs_parse_text_addrs(cell->net, result, ret, ',',
					      VL_SERVICE, AFS_VL_PORT);
	kfree(result);
	if (IS_ERR(vllist) && vllist != ERR_PTR(-ENOMEM))
		pr_err("Failed to parse DNS data %ld\n", PTR_ERR(vllist));

	return vllist;
}

/*
 * Merge an IPv4 entry into a fileserver address list.
 */
void afs_merge_fs_addr4(struct afs_addr_list *alist, __be32 xdr, u16 port)
{
	struct sockaddr_rxrpc *srx;
	u32 addr = ntohl(xdr);
	int i;

	if (alist->nr_addrs >= alist->max_addrs)
		return;

	for (i = 0; i < alist->nr_ipv4; i++) {
		struct sockaddr_in *a = &alist->addrs[i].transport.sin;
		u32 a_addr = ntohl(a->sin_addr.s_addr);
		u16 a_port = ntohs(a->sin_port);

		if (addr == a_addr && port == a_port)
			return;
		if (addr == a_addr && port < a_port)
			break;
		if (addr < a_addr)
			break;
	}

	if (i < alist->nr_addrs)
		memmove(alist->addrs + i + 1,
			alist->addrs + i,
			sizeof(alist->addrs[0]) * (alist->nr_addrs - i));

	srx = &alist->addrs[i];
	srx->srx_family = AF_RXRPC;
	srx->transport_type = SOCK_DGRAM;
	srx->transport_len = sizeof(srx->transport.sin);
	srx->transport.sin.sin_family = AF_INET;
	srx->transport.sin.sin_port = htons(port);
	srx->transport.sin.sin_addr.s_addr = xdr;
	alist->nr_ipv4++;
	alist->nr_addrs++;
}

/*
 * Merge an IPv6 entry into a fileserver address list.
 */
void afs_merge_fs_addr6(struct afs_addr_list *alist, __be32 *xdr, u16 port)
{
	struct sockaddr_rxrpc *srx;
	int i, diff;

	if (alist->nr_addrs >= alist->max_addrs)
		return;

	for (i = alist->nr_ipv4; i < alist->nr_addrs; i++) {
		struct sockaddr_in6 *a = &alist->addrs[i].transport.sin6;
		u16 a_port = ntohs(a->sin6_port);

		diff = memcmp(xdr, &a->sin6_addr, 16);
		if (diff == 0 && port == a_port)
			return;
		if (diff == 0 && port < a_port)
			break;
		if (diff < 0)
			break;
	}

	if (i < alist->nr_addrs)
		memmove(alist->addrs + i + 1,
			alist->addrs + i,
			sizeof(alist->addrs[0]) * (alist->nr_addrs - i));

	srx = &alist->addrs[i];
	srx->srx_family = AF_RXRPC;
	srx->transport_type = SOCK_DGRAM;
	srx->transport_len = sizeof(srx->transport.sin6);
	srx->transport.sin6.sin6_family = AF_INET6;
	srx->transport.sin6.sin6_port = htons(port);
	memcpy(&srx->transport.sin6.sin6_addr, xdr, 16);
	alist->nr_addrs++;
}

/*
 * Get an address to try.
 */
bool afs_iterate_addresses(struct afs_addr_cursor *ac)
{
	unsigned long set, failed;
	int index;

	if (!ac->alist)
		return false;

	set = ac->alist->responded;
	failed = ac->alist->failed;
	_enter("%lx-%lx-%lx,%d", set, failed, ac->tried, ac->index);

	ac->nr_iterations++;

	set &= ~(failed | ac->tried);

	if (!set)
		return false;

	index = READ_ONCE(ac->alist->preferred);
	if (test_bit(index, &set))
		goto selected;

	index = __ffs(set);

selected:
	ac->index = index;
	set_bit(index, &ac->tried);
	ac->responded = false;
	return true;
}

/*
 * Release an address list cursor.
 */
int afs_end_cursor(struct afs_addr_cursor *ac)
{
	struct afs_addr_list *alist;

	alist = ac->alist;
	if (alist) {
		if (ac->responded &&
		    ac->index != alist->preferred &&
		    test_bit(ac->alist->preferred, &ac->tried))
			WRITE_ONCE(alist->preferred, ac->index);
		afs_put_addrlist(alist);
		ac->alist = NULL;
	}

	return ac->error;
}
Commit	Line	Data
8b2a464c DH	1	/* Server address list management
	2	*
	3	* Copyright (C) 2017 Red Hat, Inc. All Rights Reserved.
	4	* Written by David Howells ([email protected])
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public Licence
	8	* as published by the Free Software Foundation; either version
	9	* 2 of the Licence, or (at your option) any later version.
	10	*/
	11
	12	#include <linux/slab.h>
	13	#include <linux/ctype.h>
	14	#include <linux/dns_resolver.h>
	15	#include <linux/inet.h>
	16	#include <keys/rxrpc-type.h>
	17	#include "internal.h"
	18	#include "afs_fs.h"
	19
8b2a464c DH	20	/*
	21	* Release an address list.
	22	*/
	23	void afs_put_addrlist(struct afs_addr_list *alist)
	24	{
	25	if (alist && refcount_dec_and_test(&alist->usage))
	26	call_rcu(&alist->rcu, (rcu_callback_t)kfree);
	27	}
	28
	29	/*
	30	* Allocate an address list.
	31	*/
	32	struct afs_addr_list *afs_alloc_addrlist(unsigned int nr,
	33	unsigned short service,
	34	unsigned short port)
	35	{
	36	struct afs_addr_list *alist;
	37	unsigned int i;
	38
	39	_enter("%u,%u,%u", nr, service, port);
	40
68eb64c3 DH	41	if (nr > AFS_MAX_ADDRESSES)
	42	nr = AFS_MAX_ADDRESSES;
	43
acafe7e3	44	alist = kzalloc(struct_size(alist, addrs, nr), GFP_KERNEL);
8b2a464c DH	45	if (!alist)
	46	return NULL;
	47
	48	refcount_set(&alist->usage, 1);
68eb64c3	49	alist->max_addrs = nr;
8b2a464c DH	50
	51	for (i = 0; i < nr; i++) {
	52	struct sockaddr_rxrpc *srx = &alist->addrs[i];
	53	srx->srx_family = AF_RXRPC;
	54	srx->srx_service = service;
	55	srx->transport_type = SOCK_DGRAM;
	56	srx->transport_len = sizeof(srx->transport.sin6);
	57	srx->transport.sin6.sin6_family = AF_INET6;
	58	srx->transport.sin6.sin6_port = htons(port);
	59	}
	60
	61	return alist;
	62	}
	63
	64	/*
	65	* Parse a text string consisting of delimited addresses.
	66	*/
0a5143f2 DH	67	struct afs_vlserver_list afs_parse_text_addrs(struct afs_net net,
	68	const char *text, size_t len,
	69	char delim,
	70	unsigned short service,
	71	unsigned short port)
8b2a464c	72	{
0a5143f2	73	struct afs_vlserver_list *vllist;
8b2a464c DH	74	struct afs_addr_list *alist;
8b2a464c DH	75	const char p, end = text + len;
0a5143f2	76	const char *problem;
8b2a464c	77	unsigned int nr = 0;
0a5143f2	78	int ret = -ENOMEM;
8b2a464c DH	79
	80	_enter("%.s,%c", (int)len, (int)len, text, delim);
	81
0a5143f2 DH	82	if (!len) {
0a5143f2 DH	83	_leave(" = -EDESTADDRREQ [empty]");
8b2a464c	84	return ERR_PTR(-EDESTADDRREQ);
0a5143f2	85	}
8b2a464c DH	86
	87	if (delim == ':' && (memchr(text, ',', len) \|\| !memchr(text, '.', len)))
	88	delim = ',';
	89
	90	/* Count the addresses */
	91	p = text;
	92	do {
0a5143f2 DH	93	if (!*p) {
	94	problem = "nul";
	95	goto inval;
	96	}
8b2a464c DH	97	if (*p == delim)
	98	continue;
	99	nr++;
	100	if (*p == '[') {
	101	p++;
0a5143f2 DH	102	if (p == end) {
	103	problem = "brace1";
	104	goto inval;
	105	}
8b2a464c	106	p = memchr(p, ']', end - p);
0a5143f2 DH	107	if (!p) {
	108	problem = "brace2";
	109	goto inval;
	110	}
8b2a464c DH	111	p++;
	112	if (p >= end)
	113	break;
	114	}
	115
	116	p = memchr(p, delim, end - p);
	117	if (!p)
	118	break;
	119	p++;
	120	} while (p < end);
	121
	122	_debug("%u/%u addresses", nr, AFS_MAX_ADDRESSES);
8b2a464c	123
0a5143f2 DH	124	vllist = afs_alloc_vlserver_list(1);
0a5143f2 DH	125	if (!vllist)
8b2a464c DH	126	return ERR_PTR(-ENOMEM);
8b2a464c DH	127
0a5143f2 DH	128	vllist->nr_servers = 1;
	129	vllist->servers[0].server = afs_alloc_vlserver("<dummy>", 7, AFS_VL_PORT);
	130	if (!vllist->servers[0].server)
	131	goto error_vl;
	132
	133	alist = afs_alloc_addrlist(nr, service, AFS_VL_PORT);
	134	if (!alist)
	135	goto error;
	136
8b2a464c DH	137	/* Extract the addresses */
	138	p = text;
	139	do {
01fd79e6	140	const char q, stop;
4c19bbdc DH	141	unsigned int xport = port;
	142	__be32 x[4];
	143	int family;
8b2a464c DH	144
	145	if (*p == delim) {
	146	p++;
	147	continue;
	148	}
	149
	150	if (*p == '[') {
	151	p++;
01fd79e6 DH	152	q = memchr(p, ']', end - p);
	153	} else {
	154	for (q = p; q < end; q++)
	155	if (q == '+' \|\| q == delim)
	156	break;
8b2a464c DH	157	}
8b2a464c DH	158
0a5143f2	159	if (in4_pton(p, q - p, (u8 *)&x[0], -1, &stop)) {
4c19bbdc	160	family = AF_INET;
0a5143f2	161	} else if (in6_pton(p, q - p, (u8 *)x, -1, &stop)) {
4c19bbdc	162	family = AF_INET6;
0a5143f2 DH	163	} else {
0a5143f2 DH	164	problem = "family";
8b2a464c	165	goto bad_address;
0a5143f2	166	}
8b2a464c	167
0a5143f2 DH	168	p = q;
	169	if (stop != p) {
	170	problem = "nostop";
01fd79e6	171	goto bad_address;
0a5143f2	172	}
01fd79e6	173
01fd79e6	174	if (q < end && *q == ']')
8b2a464c	175	p++;
8b2a464c DH	176
	177	if (p < end) {
	178	if (*p == '+') {
	179	/* Port number specification "+1234" */
4c19bbdc	180	xport = 0;
8b2a464c	181	p++;
0a5143f2 DH	182	if (p >= end \|\| !isdigit(*p)) {
0a5143f2 DH	183	problem = "port";
8b2a464c	184	goto bad_address;
0a5143f2	185	}
8b2a464c DH	186	do {
	187	xport *= 10;
	188	xport += *p - '0';
0a5143f2 DH	189	if (xport > 65535) {
0a5143f2 DH	190	problem = "pval";
8b2a464c	191	goto bad_address;
0a5143f2	192	}
8b2a464c DH	193	p++;
8b2a464c DH	194	} while (p < end && isdigit(*p));
8b2a464c DH	195	} else if (*p == delim) {
	196	p++;
	197	} else {
0a5143f2	198	problem = "weird";
8b2a464c DH	199	goto bad_address;
	200	}
	201	}
	202
4c19bbdc DH	203	if (family == AF_INET)
	204	afs_merge_fs_addr4(alist, x[0], xport);
	205	else
	206	afs_merge_fs_addr6(alist, x, xport);
	207
	208	} while (p < end);
8b2a464c	209
0a5143f2	210	rcu_assign_pointer(vllist->servers[0].server->addresses, alist);
8b2a464c	211	_leave(" = [nr %u]", alist->nr_addrs);
0a5143f2	212	return vllist;
8b2a464c	213
0a5143f2 DH	214	inval:
	215	_leave(" = -EINVAL [%s %zu %.s]",
	216	problem, p - text, (int)len, (int)len, text);
8b2a464c	217	return ERR_PTR(-EINVAL);
0a5143f2 DH	218	bad_address:
	219	_leave(" = -EINVAL [%s %zu %.s]",
	220	problem, p - text, (int)len, (int)len, text);
	221	ret = -EINVAL;
	222	error:
	223	afs_put_addrlist(alist);
	224	error_vl:
	225	afs_put_vlserverlist(net, vllist);
	226	return ERR_PTR(ret);
8b2a464c DH	227	}
	228
	229	/*
	230	* Compare old and new address lists to see if there's been any change.
	231	* - How to do this in better than O(Nlog(N)) time?
	232	* - We don't really want to sort the address list, but would rather take the
	233	* list as we got it so as not to undo record rotation by the DNS server.
	234	*/
	235	#if 0
	236	static int afs_cmp_addr_list(const struct afs_addr_list *a1,
	237	const struct afs_addr_list *a2)
	238	{
	239	}
	240	#endif
	241
	242	/*
	243	* Perform a DNS query for VL servers and build a up an address list.
	244	*/
0a5143f2	245	struct afs_vlserver_list afs_dns_query(struct afs_cell cell, time64_t *_expiry)
8b2a464c	246	{
0a5143f2 DH	247	struct afs_vlserver_list *vllist;
0a5143f2 DH	248	char *result = NULL;
8b2a464c DH	249	int ret;
	250
	251	_enter("%s", cell->name);
	252
0a5143f2 DH	253	ret = dns_query("afsdb", cell->name, cell->name_len, "srv=1",
	254	&result, _expiry);
	255	if (ret < 0) {
	256	_leave(" = %d [dns]", ret);
8b2a464c	257	return ERR_PTR(ret);
8b2a464c DH	258	}
8b2a464c DH	259
0a5143f2 DH	260	if (*_expiry == 0)
	261	*_expiry = ktime_get_real_seconds() + 60;
	262
	263	if (ret > 1 && result[0] == 0)
	264	vllist = afs_extract_vlserver_list(cell, result, ret);
	265	else
	266	vllist = afs_parse_text_addrs(cell->net, result, ret, ',',
	267	VL_SERVICE, AFS_VL_PORT);
	268	kfree(result);
	269	if (IS_ERR(vllist) && vllist != ERR_PTR(-ENOMEM))
	270	pr_err("Failed to parse DNS data %ld\n", PTR_ERR(vllist));
	271
	272	return vllist;
8b2a464c DH	273	}
8b2a464c DH	274
d2ddc776 DH	275	/*
	276	* Merge an IPv4 entry into a fileserver address list.
	277	*/
bf99a53c	278	void afs_merge_fs_addr4(struct afs_addr_list *alist, __be32 xdr, u16 port)
d2ddc776	279	{
46894a13	280	struct sockaddr_rxrpc *srx;
66be646b	281	u32 addr = ntohl(xdr);
d2ddc776 DH	282	int i;
d2ddc776 DH	283
68eb64c3 DH	284	if (alist->nr_addrs >= alist->max_addrs)
	285	return;
	286
d2ddc776	287	for (i = 0; i < alist->nr_ipv4; i++) {
46894a13 DH	288	struct sockaddr_in *a = &alist->addrs[i].transport.sin;
	289	u32 a_addr = ntohl(a->sin_addr.s_addr);
	290	u16 a_port = ntohs(a->sin_port);
66be646b DH	291
66be646b DH	292	if (addr == a_addr && port == a_port)
d2ddc776	293	return;
66be646b	294	if (addr == a_addr && port < a_port)
bf99a53c	295	break;
66be646b	296	if (addr < a_addr)
d2ddc776 DH	297	break;
	298	}
	299
	300	if (i < alist->nr_addrs)
	301	memmove(alist->addrs + i + 1,
	302	alist->addrs + i,
	303	sizeof(alist->addrs[0]) * (alist->nr_addrs - i));
	304
46894a13	305	srx = &alist->addrs[i];
3bf0fb6f DH	306	srx->srx_family = AF_RXRPC;
3bf0fb6f DH	307	srx->transport_type = SOCK_DGRAM;
46894a13 DH	308	srx->transport_len = sizeof(srx->transport.sin);
	309	srx->transport.sin.sin_family = AF_INET;
	310	srx->transport.sin.sin_port = htons(port);
	311	srx->transport.sin.sin_addr.s_addr = xdr;
d2ddc776 DH	312	alist->nr_ipv4++;
	313	alist->nr_addrs++;
	314	}
	315
bf99a53c DH	316	/*
	317	* Merge an IPv6 entry into a fileserver address list.
	318	*/
	319	void afs_merge_fs_addr6(struct afs_addr_list alist, __be32 xdr, u16 port)
	320	{
46894a13	321	struct sockaddr_rxrpc *srx;
bf99a53c DH	322	int i, diff;
bf99a53c DH	323
68eb64c3 DH	324	if (alist->nr_addrs >= alist->max_addrs)
	325	return;
	326
bf99a53c	327	for (i = alist->nr_ipv4; i < alist->nr_addrs; i++) {
66be646b DH	328	struct sockaddr_in6 *a = &alist->addrs[i].transport.sin6;
	329	u16 a_port = ntohs(a->sin6_port);
	330
bf99a53c	331	diff = memcmp(xdr, &a->sin6_addr, 16);
66be646b	332	if (diff == 0 && port == a_port)
bf99a53c	333	return;
66be646b	334	if (diff == 0 && port < a_port)
bf99a53c DH	335	break;
	336	if (diff < 0)
	337	break;
	338	}
	339
	340	if (i < alist->nr_addrs)
	341	memmove(alist->addrs + i + 1,
	342	alist->addrs + i,
	343	sizeof(alist->addrs[0]) * (alist->nr_addrs - i));
	344
46894a13	345	srx = &alist->addrs[i];
3bf0fb6f DH	346	srx->srx_family = AF_RXRPC;
3bf0fb6f DH	347	srx->transport_type = SOCK_DGRAM;
46894a13 DH	348	srx->transport_len = sizeof(srx->transport.sin6);
	349	srx->transport.sin6.sin6_family = AF_INET6;
	350	srx->transport.sin6.sin6_port = htons(port);
	351	memcpy(&srx->transport.sin6.sin6_addr, xdr, 16);
bf99a53c DH	352	alist->nr_addrs++;
	353	}
	354
8b2a464c DH	355	/*
	356	* Get an address to try.
	357	*/
	358	bool afs_iterate_addresses(struct afs_addr_cursor *ac)
	359	{
3bf0fb6f DH	360	unsigned long set, failed;
3bf0fb6f DH	361	int index;
8b2a464c DH	362
	363	if (!ac->alist)
	364	return false;
	365
3bf0fb6f DH	366	set = ac->alist->responded;
	367	failed = ac->alist->failed;
	368	_enter("%lx-%lx-%lx,%d", set, failed, ac->tried, ac->index);
	369
744bcd71 DH	370	ac->nr_iterations++;
744bcd71 DH	371
3bf0fb6f	372	set &= ~(failed \| ac->tried);
8b2a464c	373
3bf0fb6f DH	374	if (!set)
	375	return false;
	376
	377	index = READ_ONCE(ac->alist->preferred);
	378	if (test_bit(index, &set))
	379	goto selected;
	380
	381	index = __ffs(set);
8b2a464c	382
3bf0fb6f DH	383	selected:
	384	ac->index = index;
	385	set_bit(index, &ac->tried);
8b2a464c	386	ac->responded = false;
8b2a464c DH	387	return true;
	388	}
	389
	390	/*
	391	* Release an address list cursor.
	392	*/
	393	int afs_end_cursor(struct afs_addr_cursor *ac)
	394	{
fe4d774c DH	395	struct afs_addr_list *alist;
	396
	397	alist = ac->alist;
	398	if (alist) {
3bf0fb6f DH	399	if (ac->responded &&
	400	ac->index != alist->preferred &&
	401	test_bit(ac->alist->preferred, &ac->tried))
	402	WRITE_ONCE(alist->preferred, ac->index);
fe4d774c	403	afs_put_addrlist(alist);
3bf0fb6f	404	ac->alist = NULL;
fe4d774c	405	}
8b2a464c	406
8b2a464c DH	407	return ac->error;
8b2a464c DH	408	}