From 0332766f0d67bdc11c47dbb2afb69fad988d1212 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Th=C3=A9ophile=20Bastian?= <contact@tobast.fr>
Date: Thu, 4 Jun 2020 13:31:44 +0200
Subject: [PATCH] Bring up tun interface upon creation

---
 TunDevice.cpp | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/TunDevice.cpp b/TunDevice.cpp
index 0787f15..a7b3fe2 100644
--- a/TunDevice.cpp
+++ b/TunDevice.cpp
@@ -44,6 +44,25 @@ TunDevice::TunDevice(const std::string& dev)
     _dev_name = ifr.ifr_name;
     _fd = fd;
 
+    // Bring interface up
+    kdebugf("Bringing interface up...\n");
+    int sockfd = socket(AF_INET, SOCK_DGRAM, 0); // Any socket will do
+    if(ioctl(sockfd, SIOCGIFFLAGS, (void*) &ifr) < 0) {
+        close(fd);
+        close(sockfd);
+        throw TunDevice::InitializationError(
+                "Could not get tunnel interface flags", errno, true);
+    }
+    ifr.ifr_flags |= IFF_UP | IFF_RUNNING;
+
+    if(ioctl(sockfd, SIOCSIFFLAGS, (void*) &ifr) < 0) {
+        close(fd);
+        close(sockfd);
+        throw TunDevice::InitializationError(
+                "Could not bring tunnel interface up", errno, true);
+    }
+    close(sockfd);
+
     // The device is now fully set up
     _poll_fd.fd = _fd;
     _poll_fd.events = POLLIN;