On Wed, 07 Jul 2010 10:14:11 +0100 David Howells <[email protected]> wrote:
-----------------[snip]---------------- > diff --git a/net/dnsresolver/resolv_unc_to_ip.c > b/net/dnsresolver/resolv_unc_to_ip.c > new file mode 100644 > index 0000000..169f9d9 > --- /dev/null > +++ b/net/dnsresolver/resolv_unc_to_ip.c > @@ -0,0 +1,111 @@ > +/* > + * Copyright (c) 2007 Igor Mammedov > + * Author(s): Igor Mammedov ([email protected]) > + * Steve French ([email protected]) > + * Wang Lei ([email protected]) > + * > + * Routines used for Universal Naming Convention (UNC) path style hostname > to > + * IP address translation. For this function to work, the userspace tool > + * dns.upcall is needed and something like the following lines should be > + * added to the /etc/request-key.conf file: > + * > + * create dns_resolver * * /sbin/dns.upcall %k > + * > + * 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 <linux/module.h> > +#include <linux/slab.h> > +#include <linux/socket.h> > +#include <linux/in.h> > +#include <linux/inet.h> > +#include <linux/in6.h> > +#include <linux/string.h> > +#include <linux/dns_resolver.h> > +#include <keys/dnsresolver-type.h> > +#include "internal.h" > + > +/** > + * dns_resolve_unc_to_ip - Resolve UNC server name to ip address. > + * @unc: UNC path specifying the server > + * @ip_addr: Where to return the IP address. > + * > + * The IP address will be returned in string form, and the caller is > + * responsible for freeing it. > + * > + * Returns 0 on success, -ve on error. > + */ > +int > +dns_resolve_unc_to_ip(const char *unc, char **ip_addr) > +{ > + struct in_addr s4; > + struct in6_addr s6; > + char *name, *sep; > + int len, rc; > + > + kenter("%s,", unc); > + > + rc = -EINVAL; > + if (!ip_addr || !unc) > + goto out; > + > + len = strlen(unc); > + if (len < 3) > + goto out; > + > + /* discount leading slashes for cifs */ > + len -= 2; > + unc += 2; > + > + /* search for server name delimiter */ > + sep = memchr(unc, '\\', len); > + if (sep) > + len = sep - unc; > + kdebug("server name:%*.*s", len, len, unc); > + > + rc = -ENOMEM; > + name = kmalloc(len + 1, GFP_KERNEL); > + if (!name) > + goto out; > + > + memcpy(name, unc, len); > + name[len] = 0; > + kdebug("name to resolve '%s'", name); > + > + /* Try to convert a string to an IPv4 address */ > + rc = in4_pton(name, len, (void *)&s4.s_addr, '\\', NULL); > + if (rc > 0) { > + *ip_addr = name; > + kleave(" = 0 [UNC is IPv4]"); > + return 0; > + } > + > + /* Try to convert a string to an IPv6 address */ > + rc = in6_pton(name, len, (void *)&s6.s6_addr, '\\', NULL); > + if (rc > 0) { > + *ip_addr = name; > + kleave(" = 0 [UNC is IPv6]"); > + return 0; > + } > + > + /* perform the upcall */ > + rc = request_dns_resolution(name, NULL, ip_addr); > + kfree(name); > + > +out: > + kleave(" = %d", rc); > + return rc; > +} > +EXPORT_SYMBOL(dns_resolve_unc_to_ip); > I'm not sold that the above function really belongs in generic code. It seems like it might make more sense to have a cifs function that parses out the host portion of the UNC and then pass that to a generic function that does the in4_pton/in6_pton and then the upcall if that fails? Nice work on the set. Moving the DNS upcall into generic code is definitely a good move. -- Jeff Layton <[email protected]> -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
