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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
commit | 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch) | |
tree | a94efe259b9009378be6d90eb30d2b019d95c194 /fs/nfs/dns_resolve.c | |
parent | Initial commit. (diff) | |
download | linux-upstream/5.10.209.tar.xz linux-upstream/5.10.209.zip |
Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'fs/nfs/dns_resolve.c')
-rw-r--r-- | fs/nfs/dns_resolve.c | 481 |
1 files changed, 481 insertions, 0 deletions
diff --git a/fs/nfs/dns_resolve.c b/fs/nfs/dns_resolve.c new file mode 100644 index 000000000..e87d500ad --- /dev/null +++ b/fs/nfs/dns_resolve.c @@ -0,0 +1,481 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * linux/fs/nfs/dns_resolve.c + * + * Copyright (c) 2009 Trond Myklebust <Trond.Myklebust@netapp.com> + * + * Resolves DNS hostnames into valid ip addresses + */ + +#ifdef CONFIG_NFS_USE_KERNEL_DNS + +#include <linux/module.h> +#include <linux/sunrpc/clnt.h> +#include <linux/sunrpc/addr.h> +#include <linux/dns_resolver.h> +#include "dns_resolve.h" + +ssize_t nfs_dns_resolve_name(struct net *net, char *name, size_t namelen, + struct sockaddr *sa, size_t salen) +{ + 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/module.h> +#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/clnt.h> +#include <linux/sunrpc/addr.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 "dns_resolve.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(sizeof(*item), GFP_KERNEL); + + 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 *sa, 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(sa, &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 |