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authorWang Lei <wang840925@gmail.com>2010-08-04 15:16:38 +0100
committerSteve French <sfrench@us.ibm.com>2010-08-05 17:17:51 +0000
commit07567a5509327bcbf2c867286eb1524447c9b954 (patch)
tree35e73b223c2def7ca130b6a58aef8e93aa2bd72a /fs/afs/cell.c
parent1a4240f4764ac78adbf4b0ebb49b3bd8c72ffa11 (diff)
DNS: Make AFS go to the DNS for AFSDB records for unknown cells
Add DNS query support for AFS so that it can get the IP addresses of Volume Location servers from the DNS using an AFSDB record. This requires userspace support. /etc/request-key.conf must be configured to invoke a helper for dns_resolver type keys with a subtype of "afsdb:" in the description. Signed-off-by: Wang Lei <wang840925@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Steve French <sfrench@us.ibm.com>
Diffstat (limited to 'fs/afs/cell.c')
-rw-r--r--fs/afs/cell.c40
1 files changed, 30 insertions, 10 deletions
diff --git a/fs/afs/cell.c b/fs/afs/cell.c
index e19c13f059e..ffea35c6387 100644
--- a/fs/afs/cell.c
+++ b/fs/afs/cell.c
@@ -13,6 +13,7 @@
#include <linux/slab.h>
#include <linux/key.h>
#include <linux/ctype.h>
+#include <linux/dns_resolver.h>
#include <linux/sched.h>
#include <keys/rxrpc-type.h>
#include "internal.h"
@@ -36,6 +37,8 @@ static struct afs_cell *afs_cell_alloc(const char *name, char *vllist)
struct key *key;
size_t namelen;
char keyname[4 + AFS_MAXCELLNAME + 1], *cp, *dp, *next;
+ char *dvllist = NULL, *_vllist = NULL;
+ char delimiter = ':';
int ret;
_enter("%s,%s", name, vllist);
@@ -43,8 +46,10 @@ static struct afs_cell *afs_cell_alloc(const char *name, char *vllist)
BUG_ON(!name); /* TODO: want to look up "this cell" in the cache */
namelen = strlen(name);
- if (namelen > AFS_MAXCELLNAME)
+ if (namelen > AFS_MAXCELLNAME) {
+ _leave(" = -ENAMETOOLONG");
return ERR_PTR(-ENAMETOOLONG);
+ }
/* allocate and initialise a cell record */
cell = kzalloc(sizeof(struct afs_cell) + namelen + 1, GFP_KERNEL);
@@ -64,15 +69,31 @@ static struct afs_cell *afs_cell_alloc(const char *name, char *vllist)
INIT_LIST_HEAD(&cell->vl_list);
spin_lock_init(&cell->vl_lock);
+ /* if the ip address is invalid, try dns query */
+ if (!vllist || strlen(vllist) < 7) {
+ ret = dns_query("afsdb", name, namelen, "ipv4", &dvllist, NULL);
+ if (ret < 0) {
+ _leave(" = %d", ret);
+ return ERR_PTR(ret);
+ }
+ _vllist = dvllist;
+
+ /* change the delimiter for user-space reply */
+ delimiter = ',';
+
+ } else {
+ _vllist = vllist;
+ }
+
/* fill in the VL server list from the rest of the string */
do {
unsigned a, b, c, d;
- next = strchr(vllist, ':');
+ next = strchr(_vllist, delimiter);
if (next)
*next++ = 0;
- if (sscanf(vllist, "%u.%u.%u.%u", &a, &b, &c, &d) != 4)
+ if (sscanf(_vllist, "%u.%u.%u.%u", &a, &b, &c, &d) != 4)
goto bad_address;
if (a > 255 || b > 255 || c > 255 || d > 255)
@@ -81,7 +102,7 @@ static struct afs_cell *afs_cell_alloc(const char *name, char *vllist)
cell->vl_addrs[cell->vl_naddrs++].s_addr =
htonl((a << 24) | (b << 16) | (c << 8) | d);
- } while (cell->vl_naddrs < AFS_CELL_MAX_ADDRS && (vllist = next));
+ } while (cell->vl_naddrs < AFS_CELL_MAX_ADDRS && (_vllist = next));
/* create a key to represent an anonymous user */
memcpy(keyname, "afs@", 4);
@@ -110,6 +131,7 @@ bad_address:
ret = -EINVAL;
error:
key_put(cell->anonymous_key);
+ kfree(dvllist);
kfree(cell);
_leave(" = %d", ret);
return ERR_PTR(ret);
@@ -201,14 +223,12 @@ int afs_cell_init(char *rootcell)
}
cp = strchr(rootcell, ':');
- if (!cp) {
- printk(KERN_ERR "kAFS: no VL server IP addresses specified\n");
- _leave(" = -EINVAL");
- return -EINVAL;
- }
+ if (!cp)
+ _debug("kAFS: no VL server IP addresses specified");
+ else
+ *cp++ = 0;
/* allocate a cell record for the root cell */
- *cp++ = 0;
new_root = afs_cell_create(rootcell, cp);
if (IS_ERR(new_root)) {
_leave(" = %ld", PTR_ERR(new_root));