VPN: make the file descriptor non-blocking by default.

Change-Id: I89899b2b6a8ac64a4a052ffd501cc0221fab3ffe

1 files changed, 8 insertions, 0 deletions

diff --git a/services/jni/com_android_server_connectivity_Vpn.cpp b/services/jni/com_android_server_connectivity_Vpn.cpp
index 206df25..ae7fbfe 100644
--- a/services/jni/com_android_server_connectivity_Vpn.cpp
+++ b/services/jni/com_android_server_connectivity_Vpn.cpp
@@ -55,6 +55,7 @@ static int create_interface(int mtu, char *name, int *index)
 {
     int tun = open("/dev/tun", O_RDWR);
     int inet4 = socket(AF_INET, SOCK_DGRAM, 0);
+    int flags;
 
     ifreq ifr4;
     memset(&ifr4, 0, sizeof(ifr4));
@@ -86,6 +87,13 @@ static int create_interface(int mtu, char *name, int *index)
         goto error;
     }
 
+    // Make it non-blocking.
+    flags = fcntl(tun, F_GETFL, 0);
+    if (flags == -1 || fcntl(tun, F_SETFL, flags | O_NONBLOCK)) {
+        LOGE("Cannot set non-blocking on %s: %s", ifr4.ifr_name, strerror(errno));
+        goto error;
+    }
+
     strcpy(name, ifr4.ifr_name);
     *index = ifr4.ifr_ifindex;
     close(inet4);