From: Wang Lei <wang840925@xxxxxxxxx> 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@xxxxxxxxx> Signed-off-by: David Howells <dhowells@xxxxxxxxxx> --- fs/afs/Kconfig | 1 + fs/afs/cell.c | 40 ++++++++++++++++++++++++++++++---------- 2 files changed, 31 insertions(+), 10 deletions(-) diff --git a/fs/afs/Kconfig b/fs/afs/Kconfig index 5c4e61d..8f975f2 100644 --- a/fs/afs/Kconfig +++ b/fs/afs/Kconfig @@ -2,6 +2,7 @@ config AFS_FS tristate "Andrew File System support (AFS) (EXPERIMENTAL)" depends on INET && EXPERIMENTAL select AF_RXRPC + select DNS_RESOLVER help If you say Y here, you will get an experimental Andrew File System driver. It currently only supports unsecured read-only AFS access. diff --git a/fs/afs/cell.c b/fs/afs/cell.c index e19c13f..9eeea5f 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, "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)); -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html