diff mbox

[2/3] alfred: Add support for network namespaces

Message ID 1453953196-29943-2-git-send-email-andrew@lunn.ch (mailing list archive)
State Superseded, archived
Delegated to: Simon Wunderlich
Headers

Commit Message

Andrew Lunn Jan. 28, 2016, 3:53 a.m. UTC 
  When running within a network namespace, access to files within
debugfs have to take into account the network name space. Each
namespace has its own directory under
/sys/kernel/debug/batman_adv/netns.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
---
 batadv_query.c |  2 +-
 debugfs.c      | 49 ++++++++++++++++++++++++++++++++++++++++++++++++-
 vis/vis.h      |  2 +-
 3 files changed, 50 insertions(+), 3 deletions(-)

Comments

Simon Wunderlich Jan. 29, 2016, 12:18 p.m. UTC | #1 
On Thursday 28 January 2016 04:53:14 Andrew Lunn wrote:
> When running within a network namespace, access to files within
> debugfs have to take into account the network name space. Each
> namespace has its own directory under
> /sys/kernel/debug/batman_adv/netns.
> 
> Signed-off-by: Andrew Lunn <andrew@lunn.ch>
> ---
>  batadv_query.c |  2 +-
>  debugfs.c      | 49 ++++++++++++++++++++++++++++++++++++++++++++++++-
>  vis/vis.h      |  2 +-
>  3 files changed, 50 insertions(+), 3 deletions(-)
> 
> diff --git a/batadv_query.c b/batadv_query.c
> index c289b80..fe7c007 100644
> --- a/batadv_query.c
> +++ b/batadv_query.c
> @@ -31,7 +31,7 @@
>  #include <sys/types.h>
>  #include "debugfs.h"
> 
> -#define DEBUG_BATIF_PATH_FMT "%s/batman_adv/%s"
> +#define DEBUG_BATIF_PATH_FMT "%s/batman_adv/%s%s"
>  #define DEBUG_TRANSTABLE_GLOBAL "transtable_global"
>  #define DEBUG_ORIGINATORS "originators"
> 
> diff --git a/debugfs.c b/debugfs.c
> index fc39322..35c1bdf 100644
> --- a/debugfs.c
> +++ b/debugfs.c
> @@ -20,11 +20,15 @@
> 
>  #include "debugfs.h"
>  #include <errno.h>
> +#include <fcntl.h>
> +#include <limits.h>
>  #include <stdio.h>
>  #include <string.h>
>  #include <sys/mount.h>
>  #include <sys/stat.h>
>  #include <sys/statfs.h>
> +#include <sys/types.h>
> +#include <unistd.h>
> 
>  #ifndef DEBUGFS_MAGIC
>  #define DEBUGFS_MAGIC          0x64626720
> @@ -42,16 +46,59 @@ static const char *debugfs_known_mountpoints[] = {
>  	NULL,
>  };
> 
> +/* Return the current net namespace number. 0 is never a valid
> + * namespace, so use it to return that there is no name space
> + * support.
> + */
> +
> +static unsigned int debugfs_get_netns_inum(void)
> +{
> +	char net_path[] = "/proc/self/ns/net";
> +	struct stat netst;
> +	int netns;
> +
> +	netns = open(net_path, O_RDONLY);
> +	if (netns < 0) {
> +		if (errno == ENOENT)
> +			/* Probably means no netns support in the kernel */
> +			return 0;
> +
> +		fprintf(stderr,
> +			"Error - can't open /proc/self/ns/net for read: %s\n",
> +			strerror(errno));
> +		return 0;
> +	}
> +
> +	if (fstat(netns, &netst) < 0) {
> +		fprintf(stderr, "Stat of netns failed: %s\n",
> +			strerror(errno));
> +		return 0;

Aren't we leaking the netns file descriptor here? You could just set 
netst.st_ino = 0 instead ...

Rest looks good to me :)

Cheers,
    Simon
Andrew Lunn Feb. 2, 2016, 2:22 a.m. UTC | #2 
On Fri, Jan 29, 2016 at 01:18:13PM +0100, Simon Wunderlich wrote:
> On Thursday 28 January 2016 04:53:14 Andrew Lunn wrote:
> > When running within a network namespace, access to files within
> > debugfs have to take into account the network name space. Each
> > namespace has its own directory under
> > /sys/kernel/debug/batman_adv/netns.
> > 
> > Signed-off-by: Andrew Lunn <andrew@lunn.ch>
> > ---
> >  batadv_query.c |  2 +-
> >  debugfs.c      | 49 ++++++++++++++++++++++++++++++++++++++++++++++++-
> >  vis/vis.h      |  2 +-
> >  3 files changed, 50 insertions(+), 3 deletions(-)
> > 
> > diff --git a/batadv_query.c b/batadv_query.c
> > index c289b80..fe7c007 100644
> > --- a/batadv_query.c
> > +++ b/batadv_query.c
> > @@ -31,7 +31,7 @@
> >  #include <sys/types.h>
> >  #include "debugfs.h"
> > 
> > -#define DEBUG_BATIF_PATH_FMT "%s/batman_adv/%s"
> > +#define DEBUG_BATIF_PATH_FMT "%s/batman_adv/%s%s"
> >  #define DEBUG_TRANSTABLE_GLOBAL "transtable_global"
> >  #define DEBUG_ORIGINATORS "originators"
> > 
> > diff --git a/debugfs.c b/debugfs.c
> > index fc39322..35c1bdf 100644
> > --- a/debugfs.c
> > +++ b/debugfs.c
> > @@ -20,11 +20,15 @@
> > 
> >  #include "debugfs.h"
> >  #include <errno.h>
> > +#include <fcntl.h>
> > +#include <limits.h>
> >  #include <stdio.h>
> >  #include <string.h>
> >  #include <sys/mount.h>
> >  #include <sys/stat.h>
> >  #include <sys/statfs.h>
> > +#include <sys/types.h>
> > +#include <unistd.h>
> > 
> >  #ifndef DEBUGFS_MAGIC
> >  #define DEBUGFS_MAGIC          0x64626720
> > @@ -42,16 +46,59 @@ static const char *debugfs_known_mountpoints[] = {
> >  	NULL,
> >  };
> > 
> > +/* Return the current net namespace number. 0 is never a valid
> > + * namespace, so use it to return that there is no name space
> > + * support.
> > + */
> > +
> > +static unsigned int debugfs_get_netns_inum(void)
> > +{
> > +	char net_path[] = "/proc/self/ns/net";
> > +	struct stat netst;
> > +	int netns;
> > +
> > +	netns = open(net_path, O_RDONLY);
> > +	if (netns < 0) {
> > +		if (errno == ENOENT)
> > +			/* Probably means no netns support in the kernel */
> > +			return 0;
> > +
> > +		fprintf(stderr,
> > +			"Error - can't open /proc/self/ns/net for read: %s\n",
> > +			strerror(errno));
> > +		return 0;
> > +	}
> > +
> > +	if (fstat(netns, &netst) < 0) {
> > +		fprintf(stderr, "Stat of netns failed: %s\n",
> > +			strerror(errno));
> > +		return 0;
> 
> Aren't we leaking the netns file descriptor here?

Yes, it is leaking. I will fix that in a v2.

Thanks
     Andrew
diff mbox

Patch

diff --git a/batadv_query.c b/batadv_query.c
index c289b80..fe7c007 100644
--- a/batadv_query.c
+++ b/batadv_query.c
@@ -31,7 +31,7 @@ 
 #include <sys/types.h>
 #include "debugfs.h"
 
-#define DEBUG_BATIF_PATH_FMT "%s/batman_adv/%s"
+#define DEBUG_BATIF_PATH_FMT "%s/batman_adv/%s%s"
 #define DEBUG_TRANSTABLE_GLOBAL "transtable_global"
 #define DEBUG_ORIGINATORS "originators"
 
diff --git a/debugfs.c b/debugfs.c
index fc39322..35c1bdf 100644
--- a/debugfs.c
+++ b/debugfs.c
@@ -20,11 +20,15 @@ 
 
 #include "debugfs.h"
 #include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
 #include <stdio.h>
 #include <string.h>
 #include <sys/mount.h>
 #include <sys/stat.h>
 #include <sys/statfs.h>
+#include <sys/types.h>
+#include <unistd.h>
 
 #ifndef DEBUGFS_MAGIC
 #define DEBUGFS_MAGIC          0x64626720
@@ -42,16 +46,59 @@  static const char *debugfs_known_mountpoints[] = {
 	NULL,
 };
 
+/* Return the current net namespace number. 0 is never a valid
+ * namespace, so use it to return that there is no name space
+ * support.
+ */
+
+static unsigned int debugfs_get_netns_inum(void)
+{
+	char net_path[] = "/proc/self/ns/net";
+	struct stat netst;
+	int netns;
+
+	netns = open(net_path, O_RDONLY);
+	if (netns < 0) {
+		if (errno == ENOENT)
+			/* Probably means no netns support in the kernel */
+			return 0;
+
+		fprintf(stderr,
+			"Error - can't open /proc/self/ns/net for read: %s\n",
+			strerror(errno));
+		return 0;
+	}
+
+	if (fstat(netns, &netst) < 0) {
+		fprintf(stderr, "Stat of netns failed: %s\n",
+			strerror(errno));
+		return 0;
+	}
+	close (netns);
+
+	return netst.st_ino;
+}
+
 /* construct a full path to a debugfs element */
 int debugfs_make_path(const char *fmt, const char *mesh_iface, char *buffer,
 		      int size)
 {
+	unsigned int ns =  debugfs_get_netns_inum();
+	char ns_dir[PATH_MAX];
+
 	if (strlen(debugfs_mountpoint) == 0) {
 		buffer[0] = '\0';
 		return -1;
 	}
 
-	return snprintf(buffer, size, fmt, debugfs_mountpoint, mesh_iface);
+	if (ns) {
+		snprintf(ns_dir, PATH_MAX, "netns/%u/", ns);
+		return snprintf(buffer, size, fmt, debugfs_mountpoint, ns_dir,
+				mesh_iface);
+	} else {
+		return snprintf(buffer, size, fmt, debugfs_mountpoint, "",
+				mesh_iface);
+	}
 }
 
 static int debugfs_found;
diff --git a/vis/vis.h b/vis/vis.h
index 969ca33..9e5dc35 100644
--- a/vis/vis.h
+++ b/vis/vis.h
@@ -37,7 +37,7 @@ 
 #define UPDATE_INTERVAL				10
 
 #define SYS_IFACE_PATH				"/sys/class/net"
-#define DEBUG_BATIF_PATH_FMT			"%s/batman_adv/%s"
+#define DEBUG_BATIF_PATH_FMT			"%s/batman_adv/%s%s"
 #define SYS_MESH_IFACE_FMT			SYS_IFACE_PATH"/%s/batman_adv/mesh_iface"
 #define SYS_IFACE_STATUS_FMT			SYS_IFACE_PATH"/%s/batman_adv/iface_status"