diff options
| -rw-r--r-- | fs/cifs/dns_resolve.c | 123 | ||||
| -rw-r--r-- | fs/cifs/dns_resolve.h | 32 |
2 files changed, 155 insertions, 0 deletions
diff --git a/fs/cifs/dns_resolve.c b/fs/cifs/dns_resolve.c new file mode 100644 index 00000000000..777a086abd6 --- /dev/null +++ b/fs/cifs/dns_resolve.c @@ -0,0 +1,123 @@ +/* + * fs/cifs/dns_resolve.c + * + * Copyright (c) 2007 Igor Mammedov + * Author(s): Igor Mammedov (niallain@gmail.com) + * Steve French (sfrench@us.ibm.com) + * + * Contains the CIFS DFS upcall routines used for hostname to + * IP address translation. + * + * This library is free software; you can redistribute it and/or modify + * it under the terms of the GNU Lesser General Public License as published + * by the Free Software Foundation; either version 2.1 of the License, or + * (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See + * the GNU Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public License + * along with this library; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include <keys/user-type.h> +#include "dns_resolve.h" +#include "cifsglob.h" +#include "cifsproto.h" +#include "cifs_debug.h" + +static int dns_resolver_instantiate(struct key *key, const void *data, + size_t datalen) +{ + int rc = 0; + char *ip; + + ip = kmalloc(datalen+1, GFP_KERNEL); + if (!ip) + return -ENOMEM; + + memcpy(ip, data, datalen); + ip[datalen] = '\0'; + + rcu_assign_pointer(key->payload.data, ip); + + return rc; +} + +struct key_type key_type_dns_resolver = { + .name = "dns_resolver", + .def_datalen = sizeof(struct in_addr), + .describe = user_describe, + .instantiate = dns_resolver_instantiate, + .match = user_match, +}; + + +/* Resolves server name to ip address. + * input: + * unc - server UNC + * output: + * *ip_addr - pointer to server ip, caller responcible for freeing it. + * return 0 on success + */ +int +dns_resolve_server_name_to_ip(const char *unc, char **ip_addr) { + int rc = -EAGAIN; + struct key *rkey; + char *name; + int len; + + if ((!ip_addr) || (!unc)) + return -EINVAL; + + /* search for server name delimiter */ + len = strlen(unc); + if (len < 3) { + cFYI(1, ("%s: unc is too short: %s", __FUNCTION__, unc)); + return -EINVAL; + } + len -= 2; + name = memchr(unc+2, '\\', len); + if (!name) { + cFYI(1, ("%s: probably server name is whole unc: %s", + __FUNCTION__, unc)); + } else { + len = (name - unc) - 2/* leading // */; + } + + name = kmalloc(len+1, GFP_KERNEL); + if (!name) { + rc = -ENOMEM; + return rc; + } + memcpy(name, unc+2, len); + name[len] = 0; + + rkey = request_key(&key_type_dns_resolver, name, ""); + if (!IS_ERR(rkey)) { + len = strlen(rkey->payload.data); + *ip_addr = kmalloc(len+1, GFP_KERNEL); + if (*ip_addr) { + memcpy(*ip_addr, rkey->payload.data, len); + (*ip_addr)[len] = '\0'; + cFYI(1, ("%s: resolved: %s to %s", __FUNCTION__, + rkey->description, + *ip_addr + )); + rc = 0; + } else { + rc = -ENOMEM; + } + key_put(rkey); + } else { + cERROR(1, ("%s: unable to resolve: %s", __FUNCTION__, name)); + } + + kfree(name); + return rc; +} + + diff --git a/fs/cifs/dns_resolve.h b/fs/cifs/dns_resolve.h new file mode 100644 index 00000000000..073fdc3db41 --- /dev/null +++ b/fs/cifs/dns_resolve.h @@ -0,0 +1,32 @@ +/* + * fs/cifs/dns_resolve.h -- DNS Resolver upcall management for CIFS DFS + * Handles host name to IP address resolution + * + * Copyright (c) International Business Machines Corp., 2008 + * Author(s): Steve French (sfrench@us.ibm.com) + * + * This library is free software; you can redistribute it and/or modify + * it under the terms of the GNU Lesser General Public License as published + * by the Free Software Foundation; either version 2.1 of the License, or + * (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See + * the GNU Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public License + * along with this library; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#ifndef _DNS_RESOLVE_H +#define _DNS_RESOLVE_H + +#ifdef __KERNEL__ +#include <linux/key-type.h> +extern struct key_type key_type_dns_resolver; +extern int dns_resolve_server_name_to_ip(const char *unc, char **ip_addr); +#endif /* KERNEL */ + +#endif /* _DNS_RESOLVE_H */ |