2008-06-17 18:20:29

by Chuck Lever III

[permalink] [raw]
Subject: [PATCH 2/4] NFS: Support raw IPv6 address hostnames during NFS mount operation

Traditionally the mount command has looked for a ":" to separate the
server's hostname from the export path in the mounted on device name,
like this:

mount server:/export /mounted/on/dir

The server's hostname is "server" and the export path is "/export".

You can also substitute a specific IPv4 network address for the server
hostname, like this:

mount 192.168.0.55:/export /mounted/on/dir

Raw IPv6 addresses present a problem, however, because they look
something like this:

fe80::200:5aff:fe00:30b

Note the use of colons.

To get around the presence of colons, copy the Solaris convention used for
mounting IPv6 servers by address: wrap a raw IPv6 address with square
brackets.

Signed-off-by: Chuck Lever <[email protected]>
---

fs/nfs/super.c | 90 +++++++++++++++++++++++++++++++++++++++++++++++++++-----
1 files changed, 82 insertions(+), 8 deletions(-)


diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index 5e0eefa..98c8110 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -1215,14 +1215,9 @@ static int nfs_try_mount(struct nfs_parsed_mount_data *args,
return status;
}

-/*
- * Split "dev_name" into "hostname:export_path".
- *
- * Note: caller frees hostname and export path, even on error.
- */
-static int nfs_parse_devname(const char *dev_name,
- char **hostname, size_t maxnamlen,
- char **export_path, size_t maxpathlen)
+static int nfs_parse_simple_hostname(const char *dev_name,
+ char **hostname, size_t maxnamlen,
+ char **export_path, size_t maxpathlen)
{
size_t len;
char *colon, *comma;
@@ -1277,6 +1272,85 @@ out_path:
}

/*
+ * Hostname has square brackets around it because it contains one or
+ * more colons. We look for the first closing square bracket, and a
+ * colon must follow it.
+ */
+static int nfs_parse_protected_hostname(const char *dev_name,
+ char **hostname, size_t maxnamlen,
+ char **export_path, size_t maxpathlen)
+{
+ size_t len;
+ char *start, *end;
+
+ start = (char *)(dev_name + 1);
+
+ end = strchr(start, ']');
+ if (end == NULL)
+ goto out_bad_devname;
+ if (*(end + 1) != ':')
+ goto out_bad_devname;
+
+ len = end - start;
+ if (len > maxnamlen)
+ goto out_hostname;
+
+ /* N.B. caller will free nfs_server.hostname in all cases */
+ *hostname = kstrndup(start, len, GFP_KERNEL);
+ if (*hostname == NULL)
+ goto out_nomem;
+
+ end += 2;
+ len = strlen(end);
+ if (len > maxpathlen)
+ goto out_path;
+ *export_path = kstrndup(end, len, GFP_KERNEL);
+ if (!*export_path)
+ goto out_nomem;
+
+ return 0;
+
+out_bad_devname:
+ dfprintk(MOUNT, "NFS: device name not in host:path format\n");
+ return -EINVAL;
+
+out_nomem:
+ dfprintk(MOUNT, "NFS: not enough memory to parse device name\n");
+ return -ENOMEM;
+
+out_hostname:
+ dfprintk(MOUNT, "NFS: server hostname too long\n");
+ return -ENAMETOOLONG;
+
+out_path:
+ dfprintk(MOUNT, "NFS: export pathname too long\n");
+ return -ENAMETOOLONG;
+}
+
+/*
+ * Split "dev_name" into "hostname:export_path".
+ *
+ * The leftmost colon demarks the split between the server's hostname
+ * and the export path. If the hostname starts with a left square
+ * bracket, then it may contain colons.
+ *
+ * Note: caller frees hostname and export path, even on error.
+ */
+static int nfs_parse_devname(const char *dev_name,
+ char **hostname, size_t maxnamlen,
+ char **export_path, size_t maxpathlen)
+{
+ if (*dev_name == '[')
+ return nfs_parse_protected_hostname(dev_name,
+ hostname, maxnamlen,
+ export_path, maxpathlen);
+
+ return nfs_parse_simple_hostname(dev_name,
+ hostname, maxnamlen,
+ export_path, maxpathlen);
+}
+
+/*
* Validate the NFS2/NFS3 mount data
* - fills in the mount root filehandle
*