Allow to add an interface to a Linux bridge

Ref GNS3/gns3-server#686

Makefile

@@ -61,6 +61,7 @@ ifeq ($(shell uname), Linux)
     SRC += nio_linux_raw.c             \
            hypervisor_docker.c         \
            hypervisor_iol_bridge.c     \
+           hypervisor_brctl.c   \
            netlink/nl.c
 endif
 

README.rst

@@ -286,6 +286,12 @@ The modules that are currently defined are given below:
     docker delete_veth hostif
     100-veth interface hostif has been deleted
 
+**Linux bridge ("brctl") ***
+
+.. code:: bash
+    brctl addif virbr0 nat2
+    100-nat2 has been added to bridge virbr0
+
 **Session example**
 
 This will bridge a tap0 interface to an UDP tunnel.

hypervisor.c

@@ -39,6 +39,7 @@
 #ifdef __linux__
 #include "hypervisor_docker.h"
 #include "hypervisor_iol_bridge.h"
+#include "hypervisor_brctl.h"
 #endif
 #include "ubridge.h"
 
@@ -498,6 +499,7 @@ int run_hypervisor(char *ip_addr, int tcp_port)
 #ifdef __linux__
    hypervisor_docker_init();
    hypervisor_iol_bridge_init();
+   hypervisor_brctl_init();
 #endif
 
    signal(SIGPIPE, SIG_IGN);

hypervisor_brctl.c

@@ -0,0 +1,109 @@
+/*
+ *   This file is part of ubridge, a program to bridge network interfaces
+ *   to UDP tunnels.
+ *
+ *   Copyright (C) 2015 GNS3 Technologies Inc.
+ *
+ *   ubridge is free software: you can redistribute it and/or modify it
+ *   under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   ubridge is distributed in the hope that it will be useful, but
+ *   WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <unistd.h>
+#include <string.h>
+#include <assert.h>
+#include <netinet/in.h>
+#include <sys/ioctl.h>
+#include <net/if.h>
+#include <linux/if_bridge.h>
+#include "ubridge.h"
+#include "hypervisor.h"
+#include "hypervisor_brctl.h"
+
+
+static int cmd_addif(hypervisor_conn_t *conn, int argc, char *argv[])
+{
+    int err = -1;
+    char *bridge = argv[0];
+    char *interface = argv[1];
+    struct ifreq ifr;
+
+    int ifindex = if_nametoindex(interface);
+
+    if (ifindex == 0) {
+        hypervisor_send_reply(conn, HSC_ERR_CREATE, 1, "Could not found interface %s", interface);
+        return -1;
+    }
+
+    int br_socket_fd = socket(AF_INET, SOCK_STREAM, 0);
+
+    strncpy(ifr.ifr_name, bridge, IFNAMSIZ);
+    #ifdef SIOCBRADDIF
+        ifr.ifr_ifindex = ifindex;
+        err = ioctl(br_socket_fd, SIOCBRADDIF, &ifr);
+        if (err < 0)
+    #endif
+    {
+        unsigned long args[4] = { BRCTL_ADD_IF, ifindex, 0, 0 };
+
+        ifr.ifr_data = (char *) args;
+        err = ioctl(br_socket_fd, SIOCDEVPRIVATE, &ifr);
+    }
+
+    // When interface is already added to the bridge EBUSY is raised
+    if (err < 0 && errno != EBUSY) {
+        hypervisor_send_reply(conn, HSC_ERR_CREATE, 1, "Could not add interface %s to %s: %s", interface, bridge, strerror(errno));
+        goto out;
+    }
+
+    // Change the status of the interface to up
+    // Get the original flags
+    strncpy(ifr.ifr_name, interface, IFNAMSIZ);
+    if (ioctl(br_socket_fd, SIOCGIFFLAGS, &ifr) < 0) {
+        hypervisor_send_reply(conn, HSC_ERR_CREATE, 1, "Could not up interface %s", interface);
+        err = -1;
+        goto out;
+    }
+    // Add the up flag
+    ifr.ifr_flags |= IFF_UP;
+    if (ioctl(br_socket_fd, SIOCSIFFLAGS, &ifr) < 0) {
+        hypervisor_send_reply(conn, HSC_ERR_CREATE, 1, "Could not up interface %s", interface);
+        err = -1;
+        goto out;
+    }
+
+    hypervisor_send_reply(conn, HSC_INFO_OK, 1, "%s has been added to bridge %s", interface, bridge);
+    err = 0;
+
+out:
+    close(br_socket_fd);
+    return (err);
+}
+
+
+/* brctl commands */
+static hypervisor_cmd_t brctl_cmd_array[] = {
+   { "addif", 2, 2, cmd_addif, NULL },
+   { NULL, -1, -1, NULL, NULL },
+};
+
+/* Hypervisor brctl initialization */
+int hypervisor_brctl_init(void)
+{
+   hypervisor_module_t *module;
+
+   module = hypervisor_register_module("brctl", NULL);
+   assert(module != NULL);
+
+   hypervisor_register_cmd_array(module, brctl_cmd_array);
+   return(0);
+}

hypervisor_brctl.h

@@ -0,0 +1,26 @@
+/*
+ *   This file is part of ubridge, a program to bridge network interfaces
+ *   to UDP tunnels.
+ *
+ *   Copyright (C) 2015 GNS3 Technologies Inc.
+ *
+ *   ubridge is free software: you can redistribute it and/or modify it
+ *   under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   ubridge is distributed in the hope that it will be useful, but
+ *   WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef HYPERVISOR_BRCTL_H_
+#define HYPERVISOR_BRCTL_H_
+
+int hypervisor_brctl_init(void);
+
+#endif /* !HYPERVISOR_BRCTL_H_ */