net: clean-up tap handling logic

Tizen emulator specific logic is extracted to independent source file.
Tap interface prefix is changed to "tap-tizen".

Change-Id: I38e218936003e8bc8de51a4d0b3413872defe4c3
Signed-off-by: SeokYeon Hwang <syeon.hwang@samsung.com>
Signed-off-by: Munkyu Im <munkyu.im@samsung.com>

3 files changed, 190 insertions, 0 deletions

diff --git a/tizen/src/util/Makefile.objs b/tizen/src/util/Makefile.objs
index b860b561fb..6c2564f2f1 100644
--- a/tizen/src/util/Makefile.objs
+++ b/tizen/src/util/Makefile.objs
@@ -16,6 +16,9 @@ obj-$(CONFIG_LINUX) += osutil-linux.o
 obj-$(CONFIG_WIN32) += osutil-win32.o
 obj-$(CONFIG_DARWIN) += osutil-darwin.o
 
+# tap helper
+obj-$(CONFIG_LINUX) += tap_helper.o
+
 #sdb
 obj-y += sdb.o
 
diff --git a/tizen/src/util/tap_helper.c b/tizen/src/util/tap_helper.c
new file mode 100644
index 0000000000..6c142f6154
--- /dev/null
+++ b/tizen/src/util/tap_helper.c
@@ -0,0 +1,153 @@
+/*
+ * TAP helper
+ *
+ * Copyright (c) 2016 Samsung Electronics Co., Ltd All Rights Reserved
+ *
+ * Contact:
+ *  MunKyu Im       <munkyu.im@samsung.com>
+ *  SeokYeon Hwang  <syeon.hwang@samsung.com>
+ *
+ * This program 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 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ *
+ * Contributors:
+ * - S-Core Co., Ltd
+ *
+ */
+
+#include <sys/ioctl.h>
+#include <net/if.h>
+#include <linux/if_tun.h>
+
+#include "qemu-common.h"
+#include "qemu/error-report.h"
+
+#include "tap_helper.h"
+
+#define PATH_NET_TUN "/dev/net/tun"
+
+#include "util/new_debug_ch.h"
+DECLARE_DEBUG_CHANNEL(tap_helper);
+
+#define START_BASE_PORT 26100
+#define END_BASE_PORT 26200
+
+static bool launch_openvpn(bool ismake, const char *ifname)
+{
+    int pid, status;
+    const char* args[] = {
+        "/usr/bin/sudo",
+        "/usr/sbin/openvpn",
+        "",
+        "--dev",
+        ifname,
+        NULL
+    };
+    if (ismake) {
+        LOG_INFO("launch_openvpn make tap: %s\n", ifname);
+        args[2] = "--mktun";
+    } else {
+        LOG_INFO("launch_openvpn remove tap: %s\n", ifname);
+        args[2] = "--rmtun";
+    }
+    /* try to launch network script */
+    pid = fork();
+    if (pid == 0) {
+        execv(args[0], (char**)args);
+        _exit(1);
+    } else if (pid > 0) {
+        while (waitpid(pid, &status, 0) != pid) {
+            /* loop */
+        }
+
+        if (WIFEXITED(status) && WEXITSTATUS(status) == 0) {
+            return true;
+        }
+    }
+
+    LOG_WARNING("Could not launch openvpn\n");
+    return false;
+}
+
+void tap_create(char *ifname)
+{
+    int fd, ret, i;
+    struct ifreq ifr;
+    char dname[128];
+    int cause;
+
+    ifname[0] = '\0';
+
+    memset(&ifr, 0, sizeof(ifr));
+    ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
+
+    // clean-up legacy ifnames
+    for (i = START_BASE_PORT ; i < END_BASE_PORT; i += 10) {
+        g_snprintf(dname, sizeof(dname), "tap%d", i);
+        g_strlcpy(ifr.ifr_name, dname, IFNAMSIZ);
+
+        TFR(fd = open(PATH_NET_TUN, O_RDWR));
+        if (fd < 0) {
+            error_report("could not open %s: %m", PATH_NET_TUN);
+            return;
+        }
+
+        ret = ioctl(fd, TUNSETIFF, (void *) &ifr);
+
+        close(fd);
+
+        if (ret == 0) {
+            if (!launch_openvpn(false, dname)) {
+                LOG_INFO("Failed to remove tap interface [%s]."
+                        "The other emulator may be using this interface.\n", dname);
+            }
+        }
+    }
+
+    // clean-up and find first unused ifname
+    for (i = 0; i < 10; i++) {
+        g_snprintf(dname, sizeof(dname), "tap_tizen%d", i);
+        g_strlcpy(ifr.ifr_name, dname, IFNAMSIZ);
+
+        TFR(fd = open(PATH_NET_TUN, O_RDWR));
+        if (fd < 0) {
+            error_report("could not open %s: %m", PATH_NET_TUN);
+            return;
+        }
+
+        ret = ioctl(fd, TUNSETIFF, (void *) &ifr);
+        cause = errno;
+        close(fd);
+
+        // ret 0: exist but not used
+        // ret -1 and cause EPERM: not exist
+        if (ret == 0 || (ret == -1 && cause == EPERM)) {
+            if (ret == 0 && !launch_openvpn(false, dname)) {
+                LOG_INFO("Failed to remove tap interface [%s]."
+                        "The other emulator may be using this interface.\n", dname);
+                continue;
+            }
+            if (ifname[0] == '\0') {
+                g_strlcpy(ifname, dname, 128);
+            }
+        }
+    }
+
+    // create tap
+    if (ifname == '\0' || !launch_openvpn(true, ifname)) {
+        LOG_INFO("Tap interface creattion failed.\n");
+    }
+
+    return;
+}
diff --git a/tizen/src/util/tap_helper.h b/tizen/src/util/tap_helper.h
new file mode 100644
index 0000000000..a14169ef2b
--- /dev/null
+++ b/tizen/src/util/tap_helper.h
@@ -0,0 +1,34 @@
+/*
+ * TAP helper
+ *
+ * Copyright (c) 2016 Samsung Electronics Co., Ltd All Rights Reserved
+ *
+ * Contact:
+ *  MunKyu Im       <munkyu.im@samsung.com>
+ *  SeokYeon Hwang  <syeon.hwang@samsung.com>
+ *
+ * This program 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 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ *
+ * Contributors:
+ * - S-Core Co., Ltd
+ *
+ */
+
+#ifndef __TAP_HELPER_H__
+#define __TAP_HELPER_H__
+
+void tap_create(char *);
+
+#endif //__TAP_HELPER_H__