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// 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 (dhowells@redhat.com)
*/
#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->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;
}
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