From 355040f5769e68cd397b0917240cc9f44bc6f9e6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Adrien=20Gallou=C3=ABt?= <adrien@gallouet.fr>
Date: Fri, 10 Feb 2017 11:54:19 +0000
Subject: [PATCH] Don't destroy tun on SIGHUP

---
 src/main.c | 12 +++++++++++-
 src/tun.c  |  7 +++++++
 src/tun.h  |  9 +++++----
 3 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/src/main.c b/src/main.c
index c7f2264..88824c3 100644
--- a/src/main.c
+++ b/src/main.c
@@ -28,6 +28,7 @@
 
 static struct {
     volatile sig_atomic_t quit;
+    volatile sig_atomic_t reload;
     char *dev;
     char *keyfile;
     char *host;
@@ -87,6 +88,7 @@ fd_set_nonblock(int fd)
 static void
 gt_quit_handler(int sig)
 {
+    gt.reload = (sig == SIGHUP);
     gt.quit = 1;
 }
 
@@ -103,9 +105,9 @@ gt_set_signal(void)
     sigaction(SIGINT, &sa, NULL);
     sigaction(SIGQUIT, &sa, NULL);
     sigaction(SIGTERM, &sa, NULL);
+    sigaction(SIGHUP, &sa, NULL);
 
     sa.sa_handler = SIG_IGN;
-    sigaction(SIGHUP, &sa, NULL);
     sigaction(SIGPIPE, &sa, NULL);
     sigaction(SIGUSR1, &sa, NULL);
     sigaction(SIGUSR2, &sa, NULL);
@@ -292,6 +294,9 @@ main(int argc, char **argv)
         return 1;
     }
 
+    if (tun_set_persist(tun_fd, 0) == -1)
+        perror("tun_set_persist");
+
     struct mud *mud = mud_create(gt.bind.port, gt.ipv4, gt.ipv6,
                                  !gt.chacha20, GT_MTU(gt.mtu));
 
@@ -482,5 +487,10 @@ main(int argc, char **argv)
         }
     }
 
+    if (gt.reload && tun_fd >= 0) {
+        if (tun_set_persist(tun_fd, 1) == -1)
+            perror("tun_set_persist");
+    }
+
     return 0;
 }
diff --git a/src/tun.c b/src/tun.c
index 75e905b..eaceea8 100644
--- a/src/tun.c
+++ b/src/tun.c
@@ -17,6 +17,7 @@
 #define IFF_TUN 0x0001
 #define IFF_NO_PI 0x1000
 #define TUNSETIFF _IOW('T', 202, int)
+#define TUNSETPERSIST _IOW('T', 203, int)
 #endif
 
 #ifdef __APPLE__
@@ -260,3 +261,9 @@ tun_set_mtu(char *dev_name, int mtu)
 
     return ret;
 }
+
+int
+tun_set_persist(int fd, int on)
+{
+    return ioctl(fd, TUNSETPERSIST, on);
+}
diff --git a/src/tun.h b/src/tun.h
index f99d92a..df99d74 100644
--- a/src/tun.h
+++ b/src/tun.h
@@ -1,6 +1,7 @@
 #pragma once
 
-int tun_create  (char *, char **);
-int tun_read    (int, void *, size_t);
-int tun_write   (int, const void *, size_t);
-int tun_set_mtu (char *, int);
+int tun_create      (char *, char **);
+int tun_read        (int, void *, size_t);
+int tun_write       (int, const void *, size_t);
+int tun_set_mtu     (char *, int);
+int tun_set_persist (int, int);