batctl: Add support for network namespaces
Commit Message
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>
---
debug.h | 2 +-
debugfs.c | 49 ++++++++++++++++++++++++++++++++++++++++++++++++-
2 files changed, 49 insertions(+), 2 deletions(-)
Comments
On Thu, Jan 28, 2016 at 04:54:19AM +0100, 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.
Thanks for providing the batctl patch Andrew.
What do you think about documenting this feature in the README file as well?
Imho a few words in the "How does it work?" section plus an example on how to
use it would be really nice!
Cheers,
On Thu, Jan 28, 2016 at 12:06:38PM +0800, Antonio Quartulli wrote:
> On Thu, Jan 28, 2016 at 04:54:19AM +0100, 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.
>
> Thanks for providing the batctl patch Andrew.
>
> What do you think about documenting this feature in the README file as well?
> Imho a few words in the "How does it work?" section plus an example on how to
> use it would be really nice!
Yes, i can do that. Here is a little example for three nodes which i
used for testing.
Andrew
EMU1="ip netns exec emu1"
EMU2="ip netns exec emu2"
ip netns add emu1
ip netns add emu2
ip link add emu1-veth1 type veth peer name emu2-veth1
ip link set emu1-veth1 netns emu1
ip link set emu2-veth1 netns emu2
$EMU1 ip link set emu1-veth1 name veth1
$EMU2 ip link set emu2-veth1 name veth1
$EMU1 ip link set veth1 up
$EMU2 ip link set veth1 up
ip link add emu1-veth2 type veth peer name veth2
ip link set emu1-veth2 netns emu1
$EMU1 ip link set emu1-veth2 name veth2
$EMU1 ip link set veth2 up
ip link set veth2 up
$EMU1 batctl if add veth1
$EMU1 batctl if add veth2
$EMU1 ip link set bat0 up
$EMU2 batctl if add veth1
$EMU2 ip link set bat0 up
batctl if add veth2
ip link set bat0 up
# Give DAD time to complete
echo Waiting for DAD
sleep 4
($EMU1 alfred -m -i bat0 -u /var/run/emu1-alfred.soc) &
($EMU2 alfred -m -i bat0 -u /var/run/emu2-alfred.soc) &
alfred -m -i bat0 &
sleep 1
($EMU1 batadv-vis -s -u /var/run/emu1-alfred.soc) &
($EMU2 batadv-vis -s -u /var/run/emu2-alfred.soc) &
batadv-vis -s &
@@ -25,7 +25,7 @@
#include <stddef.h>
#include "main.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_LOG "log"
#define DEBUG_ROUTING_ALGOS "routing_algos"
@@ -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
@@ -39,15 +43,58 @@ 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, 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;