upstream commit

Expose devices allocated for tun/tap forwarding.

At the client, the device may be obtained from a new %T expansion
for LocalCommand.

At the server, the allocated devices will be listed in a
SSH_TUNNEL variable exposed to the environment of any user sessions
started after the tunnel forwarding was established.

ok markus

Upstream-ID: e61e53f8ae80566e9ddc0d67a5df5bdf2f3c9f9e

2 files changed, 15 insertions, 3 deletions

diff --git a/openbsd-compat/port-tun.c b/openbsd-compat/port-tun.c
index 7579c6084..0e75c911d 100644
--- a/openbsd-compat/port-tun.c
+++ b/openbsd-compat/port-tun.c
@@ -56,12 +56,15 @@
 #include <linux/if_tun.h>
 
 int
-sys_tun_open(int tun, int mode)
+sys_tun_open(int tun, int mode, char **ifname)
 {
         struct ifreq ifr;
         int fd = -1;
         const char *name = NULL;
 
+        if (ifname != NULL)
+                *ifname = NULL;
+
         if ((fd = open("/dev/net/tun", O_RDWR)) == -1) {
                 debug("%s: failed to open tunnel control interface: %s",
                     __func__, strerror(errno));
@@ -99,6 +102,9 @@ sys_tun_open(int tun, int mode)
         else
                 debug("%s: %s mode %d fd %d", __func__, ifr.ifr_name, mode, fd);
 
+        if (ifname != NULL && (*ifname = strdup(ifr.ifr_name)))
+                goto failed;
+
         return (fd);
 
  failed:
@@ -116,13 +122,16 @@ sys_tun_open(int tun, int mode)
 #endif
 
 int
-sys_tun_open(int tun, int mode)
+sys_tun_open(int tun, int mode, char **ifname)
 {
         struct ifreq ifr;
         char name[100];
         int fd = -1, sock, flag;
         const char *tunbase = "tun";
 
+        if (ifname != NULL)
+                *ifname = NULL;
+
         if (mode == SSH_TUNMODE_ETHERNET) {
 #ifdef SSH_TUN_NO_L2
                 debug("%s: no layer 2 tunnelling support", __func__);
@@ -180,6 +189,9 @@ sys_tun_open(int tun, int mode)
                         goto failed;
         }
 
+        if (ifname != NULL && (*ifname = strdup(ifr.ifr_name)))
+                goto failed;
+
         close(sock);
         return (fd);
 
diff --git a/openbsd-compat/port-tun.h b/openbsd-compat/port-tun.h
index 103514370..926bc93e1 100644
--- a/openbsd-compat/port-tun.h
+++ b/openbsd-compat/port-tun.h
@@ -22,7 +22,7 @@ struct ssh;
 
 #if defined(SSH_TUN_LINUX) || defined(SSH_TUN_FREEBSD)
 # define CUSTOM_SYS_TUN_OPEN
-int       sys_tun_open(int, int);
+int       sys_tun_open(int, int, char **);
 #endif
 
 #if defined(SSH_TUN_COMPAT_AF) || defined(SSH_TUN_PREPEND_AF)