passt: Add support for multiple instances in different network namespaces

...sharing the same filesystem. Instead of a fixed path for the UNIX
domain socket, passt now uses a path with a counter, probing for
existing instances, and picking the first free one.

The demo script is updated accordingly -- it can now be started several
times to create multiple namespaces with an instance of passt each,
with addressing reflecting separate subnets, and NDP proxying between
them.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/passt.h b/passt.h
index bfbdc06..28840fc 100644
--- a/passt.h
+++ b/passt.h
@@ -1,4 +1,5 @@
-#define UNIX_SOCK_PATH	"/tmp/passt.socket"
+#define UNIX_SOCK_MAX		100
+#define UNIX_SOCK_PATH		"/tmp/passt_%i.socket"
 
 /**
  * struct tap_msg - Generic message descriptor for arrays of messages
@@ -26,6 +27,8 @@ struct fqdn {
 	char n[NS_MAXDNAME];
 };
 
+#include <net/if.h>
+
 /**
  * struct ctx - Execution context
  * @epollfd:		file descriptor for epoll instance