[PATCH 0/2] command line IPv6 support for exportfs

[PATCH 0/2] command line IPv6 support for exportfs

[Chuck Lever]

Though /etc/exports can contain IPv6 literals as client names, the
exportfs command doesn't allow an IPv6 literal when adding or
removing a temporary export.

  exportfs [-u] client:/path

If "client" is an IPv6 presentation address, it contains colons.
The problem is that exportfs already uses a colon to separate the
client identifier from the export pathname.

To escape colons in the client name, adopt the same mechanism that
is used for mount.nfs.  Users wrap IPv6 literals in square brackets.

exportfs has to be a little more complicated than mount.nfs,
however.  It must still be able to distinguish hostname wildcards
that use brackets, and be able to deal with network address
prefixes.

With this patch series,

  [abc]-machine.example.org:/export

  192.168.76.16:/share

  [2604:8800:100:81fc:82ee:73ff:fe43:d64f]:/export/home

  [fe80::]/64:/var/tmp

are now all accepted by exportfs.

---

Chuck Lever (2):
      exportfs: Refactor exportfs() and unexportfs()
      exportfs: Support raw IPv6 addresses with "client:/path"


 utils/exportfs/exportfs.c   |  134 ++++++++++++++++++++++++++++++++++++-------
 utils/exportfs/exportfs.man |   16 +++++
 2 files changed, 127 insertions(+), 23 deletions(-)

-- 
Chuck Lever

[PATCH 1/2] exportfs: Refactor exportfs() and unexportfs()

[Chuck Lever]

Separate parsing the "client:/path" argument from the actual
processing.

BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=817557
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 utils/exportfs/exportfs.c |   74 +++++++++++++++++++++++++++++++--------------
 1 file changed, 51 insertions(+), 23 deletions(-)

diff --git a/utils/exportfs/exportfs.c b/utils/exportfs/exportfs.c
index 8c86790..771d6eb 100644
--- a/utils/exportfs/exportfs.c
+++ b/utils/exportfs/exportfs.c
@@ -299,23 +299,13 @@ export_all(int verbose)
 
 
 static void
-exportfs(char *arg, char *options, int verbose)
+exportfs_parsed(char *hname, char *path, char *options, int verbose)
 {
 	struct exportent *eep;
 	nfs_export	*exp = NULL;
 	struct addrinfo	*ai = NULL;
-	char		*path;
-	char		*hname = arg;
 	int		htype;
 
-	if ((path = strchr(arg, ':')) != NULL)
-		*path++ = '\0';
-
-	if (!path || *path != '/') {
-		xlog(L_ERROR, "Invalid exporting option: %s", arg);
-		return;
-	}
-
 	if ((htype = client_gettype(hname)) == MCL_FQDN) {
 		ai = host_addrinfo(hname);
 		if (ai != NULL) {
@@ -345,24 +335,38 @@ out:
 	freeaddrinfo(ai);
 }
 
+static int exportfs_legacy(char *arg, char *options, int verbose)
+{
+	char *path;
+
+	if ((path = strchr(arg, ':')) != NULL)
+		*path++ = '\0';
+
+	if (!path || *path != '/')
+		return 1;
+
+	exportfs_parsed(arg, path, options, verbose);
+	return 0;
+}
+
 static void
-unexportfs(char *arg, int verbose)
+exportfs(char *arg, char *options, int verbose)
+{
+	int failed;
+
+	failed = exportfs_legacy(arg, options, verbose);
+	if (failed)
+		xlog(L_ERROR, "Invalid export syntax: %s", arg);
+}
+
+static void
+unexportfs_parsed(char *hname, char *path, int verbose)
 {
 	nfs_export	*exp;
 	struct addrinfo *ai = NULL;
-	char		*path;
-	char		*hname = arg;
 	int		htype;
 	int		success = 0;
 
-	if ((path = strchr(arg, ':')) != NULL)
-		*path++ = '\0';
-
-	if (!path || *path != '/') {
-		xlog(L_ERROR, "Invalid unexporting option: %s", arg);
-		return;
-	}
-
 	if ((htype = client_gettype(hname)) == MCL_FQDN) {
 		ai = host_addrinfo(hname);
 		if (ai)
@@ -403,11 +407,35 @@ unexportfs(char *arg, int verbose)
 		success = 1;
 	}
 	if (!success)
-		xlog(L_ERROR, "Could not find '%s:%s' to unexport.", arg, path);
+		xlog(L_ERROR, "Could not find '%s:%s' to unexport.", hname, path);
 
 	freeaddrinfo(ai);
 }
 
+static int unexportfs_legacy(char *arg, int verbose)
+{
+	char *path;
+
+	if ((path = strchr(arg, ':')) != NULL)
+		*path++ = '\0';
+
+	if (!path || *path != '/')
+		return 1;
+
+	unexportfs_parsed(arg, path, verbose);
+	return 0;
+}
+
+static void
+unexportfs(char *arg, int verbose)
+{
+	int failed;
+
+	failed = unexportfs_legacy(arg, verbose);
+	if (failed)
+		xlog(L_ERROR, "Invalid export syntax: %s", arg);
+}
+
 static int can_test(void)
 {
 	char buf[1024];

[PATCH 2/2] exportfs: Support raw IPv6 addresses with "client:/path"

[Chuck Lever]

Wrap IPv6 presentation addresses in square brackets.  This echoes
the same syntax used when specifying IPv6 server addresses with the
mount.nfs command.

BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=817557
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 utils/exportfs/exportfs.c   |   64 ++++++++++++++++++++++++++++++++++++++++++-
 utils/exportfs/exportfs.man |   16 +++++++++++
 2 files changed, 78 insertions(+), 2 deletions(-)

diff --git a/utils/exportfs/exportfs.c b/utils/exportfs/exportfs.c
index 771d6eb..2c8d64a 100644
--- a/utils/exportfs/exportfs.c
+++ b/utils/exportfs/exportfs.c
@@ -349,12 +349,42 @@ static int exportfs_legacy(char *arg, char *options, int verbose)
 	return 0;
 }
 
+static int exportfs_ipv6(char *arg, char *options, int verbose)
+{
+	char *path, *c, hname[NI_MAXHOST + strlen("/128")];
+
+	arg++;
+	c = strchr(arg, ']');
+	if (c == NULL)
+		return 1;
+	strncpy(hname, arg, c - arg);
+
+	/* no colon means this is a wildcarded DNS hostname */
+	if (strchr(hname, ':') == NULL)
+		return exportfs_legacy(--arg, options, verbose);
+
+	path = strstr(c, ":/");
+	if (path == NULL)
+		return 1;
+	*path++ = '\0';
+
+	/* if there's anything between the closing brace and the
+	 * path separator, it's probably a prefix length */
+	strcat(hname, ++c);
+
+	exportfs_parsed(hname, path, options, verbose);
+	return 0;
+}
+
 static void
 exportfs(char *arg, char *options, int verbose)
 {
 	int failed;
 
-	failed = exportfs_legacy(arg, options, verbose);
+	if (*arg == '[')
+		failed = exportfs_ipv6(arg, options, verbose);
+	else
+		failed = exportfs_legacy(arg, options, verbose);
 	if (failed)
 		xlog(L_ERROR, "Invalid export syntax: %s", arg);
 }
@@ -426,12 +456,42 @@ static int unexportfs_legacy(char *arg, int verbose)
 	return 0;
 }
 
+static int unexportfs_ipv6(char *arg, int verbose)
+{
+	char *path, *c, hname[NI_MAXHOST + strlen("/128")];
+
+	arg++;
+	c = strchr(arg, ']');
+	if (c == NULL)
+		return 1;
+	strncpy(hname, arg, c - arg);
+
+	/* no colon means this is a wildcarded DNS hostname */
+	if (strchr(hname, ':') == NULL)
+		return unexportfs_legacy(--arg, verbose);
+
+	path = strstr(c, ":/");
+	if (path == NULL)
+		return 1;
+	*path++ = '\0';
+
+	/* if there's anything between the closing brace and the
+	 * path separator, it's probably a prefix length */
+	strcat(hname, ++c);
+
+	unexportfs_parsed(hname, path, verbose);
+	return 0;
+}
+
 static void
 unexportfs(char *arg, int verbose)
 {
 	int failed;
 
-	failed = unexportfs_legacy(arg, verbose);
+	if (*arg == '[')
+		failed = unexportfs_ipv6(arg, verbose);
+	else
+		failed = unexportfs_legacy(arg, verbose);
 	if (failed)
 		xlog(L_ERROR, "Invalid export syntax: %s", arg);
 }
diff --git a/utils/exportfs/exportfs.man b/utils/exportfs/exportfs.man
index d481645..75d952a 100644
--- a/utils/exportfs/exportfs.man
+++ b/utils/exportfs/exportfs.man
@@ -159,6 +159,14 @@ along with the client or clients who are permitted to access it.
 See
 .B exports(5)
 for a description of supported options and access list formats.
+.PP
+IPv6 presentation addresses contain colons, which are already used
+to separate the "host" and "path" command line arguments.
+When specifying a client using a raw IPv6 address,
+enclose the address in square brackets.
+For IPv6 network addresses, place the prefix just after the closing
+bracket.
+.PP
 To export a directory to the world, simply specify
 .IR :/path .
 .PP
@@ -244,6 +252,14 @@ and files under
 .nf
 .B "# exportfs -au
 .fi
+.PP
+To export the
+.I /usr/tmp
+directory to IPv6 link-local clients:
+.PP
+.nf
+.B "# exportfs [fe80::]/64:/usr/tmp
+.fi
 .SH USAGE NOTES
 Exporting to IP networks or DNS and NIS domains does not enable clients
 from these groups to access NFS immediately.

Re: [PATCH 0/2] command line IPv6 support for exportfs

[Steve Dickson]

On 03/12/2014 01:47 PM, Chuck Lever wrote:
> Though /etc/exports can contain IPv6 literals as client names, the
> exportfs command doesn't allow an IPv6 literal when adding or
> removing a temporary export.
> 
>   exportfs [-u] client:/path
> 
> If "client" is an IPv6 presentation address, it contains colons.
> The problem is that exportfs already uses a colon to separate the
> client identifier from the export pathname.
> 
> To escape colons in the client name, adopt the same mechanism that
> is used for mount.nfs.  Users wrap IPv6 literals in square brackets.
> 
> exportfs has to be a little more complicated than mount.nfs,
> however.  It must still be able to distinguish hostname wildcards
> that use brackets, and be able to deal with network address
> prefixes.
> 
> With this patch series,
> 
>   [abc]-machine.example.org:/export
> 
>   192.168.76.16:/share
> 
>   [2604:8800:100:81fc:82ee:73ff:fe43:d64f]:/export/home
> 
>   [fe80::]/64:/var/tmp
> 
> are now all accepted by exportfs.
> 
> ---
> 
> Chuck Lever (2):
>       exportfs: Refactor exportfs() and unexportfs()
>       exportfs: Support raw IPv6 addresses with "client:/path"
Both were committed...

steved.

> 
> 
>  utils/exportfs/exportfs.c   |  134 ++++++++++++++++++++++++++++++++++++-------
>  utils/exportfs/exportfs.man |   16 +++++
>  2 files changed, 127 insertions(+), 23 deletions(-)
>