#include <linux/module.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/addr.h>
#include "dns_resolve.h"
#ifdef CONFIG_NFS_USE_KERNEL_DNS
#include <linux/dns_resolver.h>
ssize_t nfs_dns_resolve_name(struct net *net, char *name, size_t namelen,
struct sockaddr_storage *ss, size_t salen)
{
struct sockaddr *sa = (struct sockaddr *)ss;
ssize_t ret;
char *ip_addr = NULL;
int ip_len;
ip_len = dns_query(net, NULL, name, namelen, NULL, &ip_addr, NULL,
false);
if (ip_len > 0)
ret = rpc_pton(net, ip_addr, ip_len, sa, salen);
else
ret = -ESRCH;
kfree(ip_addr);
return ret;
}
#else
#include <linux/hash.h>
#include <linux/string.h>
#include <linux/kmod.h>
#include <linux/slab.h>
#include <linux/socket.h>
#include <linux/seq_file.h>
#include <linux/inet.h>
#include <linux/sunrpc/cache.h>
#include <linux/sunrpc/svcauth.h>
#include <linux/sunrpc/rpc_pipe_fs.h>
#include <linux/nfs_fs.h>
#include "nfs4_fs.h"
#include "cache_lib.h"
#include "netns.h"
#define NFS_DNS_HASHBITS 4
#define NFS_DNS_HASHTBL_SIZE (1 << NFS_DNS_HASHBITS)
struct nfs_dns_ent {
struct cache_head h;
char *hostname;
size_t namelen;
struct sockaddr_storage addr;
size_t addrlen;
struct rcu_head rcu_head;
};
static void nfs_dns_ent_update(struct cache_head *cnew,
struct cache_head *ckey)
{
struct nfs_dns_ent *new;
struct nfs_dns_ent *key;
new = container_of(cnew, struct nfs_dns_ent, h);
key = container_of(ckey, struct nfs_dns_ent, h);
memcpy(&new->addr, &key->addr, key->addrlen);
new->addrlen = key->addrlen;
}
static void nfs_dns_ent_init(struct cache_head *cnew,
struct cache_head *ckey)
{
struct nfs_dns_ent *new;
struct nfs_dns_ent *key;
new = container_of(cnew, struct nfs_dns_ent, h);
key = container_of(ckey, struct nfs_dns_ent, h);
kfree(new->hostname);
new->hostname = kmemdup_nul(key->hostname, key->namelen, GFP_KERNEL);
if (new->hostname) {
new->namelen = key->namelen;
nfs_dns_ent_update(cnew, ckey);
} else {
new->namelen = 0;
new->addrlen = 0;
}
}
static void nfs_dns_ent_free_rcu(struct rcu_head *head)
{
struct nfs_dns_ent *item;
item = container_of(head, struct nfs_dns_ent, rcu_head);
kfree(item->hostname);
kfree(item);
}
static void nfs_dns_ent_put(struct kref *ref)
{
struct nfs_dns_ent *item;
item = container_of(ref, struct nfs_dns_ent, h.ref);
call_rcu(&item->rcu_head, nfs_dns_ent_free_rcu);
}
static struct cache_head *nfs_dns_ent_alloc(void)
{
struct nfs_dns_ent *item = kmalloc_obj(*item);
if (item != NULL) {
item->hostname = NULL;
item->namelen = 0;
item->addrlen = 0;
return &item->h;
}
return NULL;
};
static unsigned int nfs_dns_hash(const struct nfs_dns_ent *key)
{
return hash_str(key->hostname, NFS_DNS_HASHBITS);
}
static void nfs_dns_request(struct cache_detail *cd,
struct cache_head *ch,
char **bpp, int *blen)
{
struct nfs_dns_ent *key = container_of(ch, struct nfs_dns_ent, h);
qword_add(bpp, blen, key->hostname);
(*bpp)[-1] = '\n';
}
static int nfs_dns_upcall(struct cache_detail *cd,
struct cache_head *ch)
{
struct nfs_dns_ent *key = container_of(ch, struct nfs_dns_ent, h);
if (test_and_set_bit(CACHE_PENDING, &ch->flags))
return 0;
if (!nfs_cache_upcall(cd, key->hostname))
return 0;
clear_bit(CACHE_PENDING, &ch->flags);
return sunrpc_cache_pipe_upcall_timeout(cd, ch);
}
static int nfs_dns_match(struct cache_head *ca,
struct cache_head *cb)
{
struct nfs_dns_ent *a;
struct nfs_dns_ent *b;
a = container_of(ca, struct nfs_dns_ent, h);
b = container_of(cb, struct nfs_dns_ent, h);
if (a->namelen == 0 || a->namelen != b->namelen)
return 0;
return memcmp(a->hostname, b->hostname, a->namelen) == 0;
}
static int nfs_dns_show(struct seq_file *m, struct cache_detail *cd,
struct cache_head *h)
{
struct nfs_dns_ent *item;
long ttl;
if (h == NULL) {
seq_puts(m, "# ip address hostname ttl\n");
return 0;
}
item = container_of(h, struct nfs_dns_ent, h);
ttl = item->h.expiry_time - seconds_since_boot();
if (ttl < 0)
ttl = 0;
if (!test_bit(CACHE_NEGATIVE, &h->flags)) {
char buf[INET6_ADDRSTRLEN+IPV6_SCOPE_ID_LEN+1];
rpc_ntop((struct sockaddr *)&item->addr, buf, sizeof(buf));
seq_printf(m, "%15s ", buf);
} else
seq_puts(m, "<none> ");
seq_printf(m, "%15s %ld\n", item->hostname, ttl);
return 0;
}
static struct nfs_dns_ent *nfs_dns_lookup(struct cache_detail *cd,
struct nfs_dns_ent *key)
{
struct cache_head *ch;
ch = sunrpc_cache_lookup_rcu(cd,
&key->h,
nfs_dns_hash(key));
if (!ch)
return NULL;
return container_of(ch, struct nfs_dns_ent, h);
}
static struct nfs_dns_ent *nfs_dns_update(struct cache_detail *cd,
struct nfs_dns_ent *new,
struct nfs_dns_ent *key)
{
struct cache_head *ch;
ch = sunrpc_cache_update(cd,
&new->h, &key->h,
nfs_dns_hash(key));
if (!ch)
return NULL;
return container_of(ch, struct nfs_dns_ent, h);
}
static int nfs_dns_parse(struct cache_detail *cd, char *buf, int buflen)
{
char buf1[NFS_DNS_HOSTNAME_MAXLEN+1];
struct nfs_dns_ent key, *item;
unsigned int ttl;
ssize_t len;
int ret = -EINVAL;
if (buf[buflen-1] != '\n')
goto out;
buf[buflen-1] = '\0';
len = qword_get(&buf, buf1, sizeof(buf1));
if (len <= 0)
goto out;
key.addrlen = rpc_pton(cd->net, buf1, len,
(struct sockaddr *)&key.addr,
sizeof(key.addr));
len = qword_get(&buf, buf1, sizeof(buf1));
if (len <= 0)
goto out;
key.hostname = buf1;
key.namelen = len;
memset(&key.h, 0, sizeof(key.h));
if (get_uint(&buf, &ttl) < 0)
goto out;
if (ttl == 0)
goto out;
key.h.expiry_time = ttl + seconds_since_boot();
ret = -ENOMEM;
item = nfs_dns_lookup(cd, &key);
if (item == NULL)
goto out;
if (key.addrlen == 0)
set_bit(CACHE_NEGATIVE, &key.h.flags);
item = nfs_dns_update(cd, &key, item);
if (item == NULL)
goto out;
ret = 0;
cache_put(&item->h, cd);
out:
return ret;
}
static int do_cache_lookup(struct cache_detail *cd,
struct nfs_dns_ent *key,
struct nfs_dns_ent **item,
struct nfs_cache_defer_req *dreq)
{
int ret = -ENOMEM;
*item = nfs_dns_lookup(cd, key);
if (*item) {
ret = cache_check(cd, &(*item)->h, &dreq->req);
if (ret)
*item = NULL;
}
return ret;
}
static int do_cache_lookup_nowait(struct cache_detail *cd,
struct nfs_dns_ent *key,
struct nfs_dns_ent **item)
{
int ret = -ENOMEM;
*item = nfs_dns_lookup(cd, key);
if (!*item)
goto out_err;
ret = -ETIMEDOUT;
if (!test_bit(CACHE_VALID, &(*item)->h.flags)
|| (*item)->h.expiry_time < seconds_since_boot()
|| cd->flush_time > (*item)->h.last_refresh)
goto out_put;
ret = -ENOENT;
if (test_bit(CACHE_NEGATIVE, &(*item)->h.flags))
goto out_put;
return 0;
out_put:
cache_put(&(*item)->h, cd);
out_err:
*item = NULL;
return ret;
}
static int do_cache_lookup_wait(struct cache_detail *cd,
struct nfs_dns_ent *key,
struct nfs_dns_ent **item)
{
struct nfs_cache_defer_req *dreq;
int ret = -ENOMEM;
dreq = nfs_cache_defer_req_alloc();
if (!dreq)
goto out;
ret = do_cache_lookup(cd, key, item, dreq);
if (ret == -EAGAIN) {
ret = nfs_cache_wait_for_upcall(dreq);
if (!ret)
ret = do_cache_lookup_nowait(cd, key, item);
}
nfs_cache_defer_req_put(dreq);
out:
return ret;
}
ssize_t nfs_dns_resolve_name(struct net *net, char *name,
size_t namelen, struct sockaddr_storage *ss, size_t salen)
{
struct nfs_dns_ent key = {
.hostname = name,
.namelen = namelen,
};
struct nfs_dns_ent *item = NULL;
ssize_t ret;
struct nfs_net *nn = net_generic(net, nfs_net_id);
ret = do_cache_lookup_wait(nn->nfs_dns_resolve, &key, &item);
if (ret == 0) {
if (salen >= item->addrlen) {
memcpy(ss, &item->addr, item->addrlen);
ret = item->addrlen;
} else
ret = -EOVERFLOW;
cache_put(&item->h, nn->nfs_dns_resolve);
} else if (ret == -ENOENT)
ret = -ESRCH;
return ret;
}
static struct cache_detail nfs_dns_resolve_template = {
.owner = THIS_MODULE,
.hash_size = NFS_DNS_HASHTBL_SIZE,
.name = "dns_resolve",
.cache_put = nfs_dns_ent_put,
.cache_upcall = nfs_dns_upcall,
.cache_request = nfs_dns_request,
.cache_parse = nfs_dns_parse,
.cache_show = nfs_dns_show,
.match = nfs_dns_match,
.init = nfs_dns_ent_init,
.update = nfs_dns_ent_update,
.alloc = nfs_dns_ent_alloc,
};
int nfs_dns_resolver_cache_init(struct net *net)
{
int err;
struct nfs_net *nn = net_generic(net, nfs_net_id);
nn->nfs_dns_resolve = cache_create_net(&nfs_dns_resolve_template, net);
if (IS_ERR(nn->nfs_dns_resolve))
return PTR_ERR(nn->nfs_dns_resolve);
err = nfs_cache_register_net(net, nn->nfs_dns_resolve);
if (err)
goto err_reg;
return 0;
err_reg:
cache_destroy_net(nn->nfs_dns_resolve, net);
return err;
}
void nfs_dns_resolver_cache_destroy(struct net *net)
{
struct nfs_net *nn = net_generic(net, nfs_net_id);
nfs_cache_unregister_net(net, nn->nfs_dns_resolve);
cache_destroy_net(nn->nfs_dns_resolve, net);
}
static int nfs4_dns_net_init(struct net *net)
{
return nfs_dns_resolver_cache_init(net);
}
static void nfs4_dns_net_exit(struct net *net)
{
nfs_dns_resolver_cache_destroy(net);
}
static struct pernet_operations nfs4_dns_resolver_ops = {
.init = nfs4_dns_net_init,
.exit = nfs4_dns_net_exit,
};
static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
void *ptr)
{
struct super_block *sb = ptr;
struct net *net = sb->s_fs_info;
struct nfs_net *nn = net_generic(net, nfs_net_id);
struct cache_detail *cd = nn->nfs_dns_resolve;
int ret = 0;
if (cd == NULL)
return 0;
if (!try_module_get(THIS_MODULE))
return 0;
switch (event) {
case RPC_PIPEFS_MOUNT:
ret = nfs_cache_register_sb(sb, cd);
break;
case RPC_PIPEFS_UMOUNT:
nfs_cache_unregister_sb(sb, cd);
break;
default:
ret = -ENOTSUPP;
break;
}
module_put(THIS_MODULE);
return ret;
}
static struct notifier_block nfs_dns_resolver_block = {
.notifier_call = rpc_pipefs_event,
};
int nfs_dns_resolver_init(void)
{
int err;
err = register_pernet_subsys(&nfs4_dns_resolver_ops);
if (err < 0)
goto out;
err = rpc_pipefs_notifier_register(&nfs_dns_resolver_block);
if (err < 0)
goto out1;
return 0;
out1:
unregister_pernet_subsys(&nfs4_dns_resolver_ops);
out:
return err;
}
void nfs_dns_resolver_destroy(void)
{
rpc_pipefs_notifier_unregister(&nfs_dns_resolver_block);
unregister_pernet_subsys(&nfs4_dns_resolver_ops);
}
#endif
