From 363ad7103507bcc092fde61c3b60bd3cfbf60aaa Mon Sep 17 00:00:00 2001
From: James Bekkema <james@sparklabs.com>
Date: Mon, 23 Jul 2018 13:21:53 +1000
Subject: [PATCH] Restore functionality of route-gateway's dhcp parameter, and
 expand to support routes using vpn_gateway.

---
 src/openvpn/init.c  |  1 +
 src/openvpn/route.c | 32 ++++++++++++++++++++++++++++++--
 src/openvpn/route.h |  3 +++
 3 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/src/openvpn/init.c b/src/openvpn/init.c
index d28d1fd2..057dbb4b 100644
--- a/src/openvpn/init.c
+++ b/src/openvpn/init.c
@@ -1396,6 +1396,7 @@ do_init_route_list(const struct options *options,
     if (init_route_list(route_list,
                         options->routes,
                         gw,
+                        options->route_gateway_via_dhcp,
                         metric,
                         link_socket_current_remote(link_socket_info),
                         es))
diff --git a/src/openvpn/route.c b/src/openvpn/route.c
index ff392308..ad8ea135 100644
--- a/src/openvpn/route.c
+++ b/src/openvpn/route.c
@@ -295,6 +295,12 @@ is_special_addr(const char *addr_str)
     }
 }
 
+static bool
+should_use_dhcp_gateway(const char *gateway, const struct route_list *rl)
+{
+    return (rl->spec.flags & RTSA_DHCP_ENDPOINT && (!is_route_parm_defined(gateway) || !strcmp(gateway, "vpn_gateway")));
+}
+
 static bool
 init_route(struct route_ipv4 *r,
            struct addrinfo **network_list,
@@ -362,7 +368,11 @@ init_route(struct route_ipv4 *r,
 
     /* gateway */
 
-    if (is_route_parm_defined(ro->gateway))
+    if (should_use_dhcp_gateway(ro->gateway, rl))
+    {
+        r->flags |= RT_DHCP_GATEWAY;
+    }
+    else if (is_route_parm_defined(ro->gateway))
     {
         if (!get_special_addr(rl, ro->gateway, &r->gateway, &status))
         {
@@ -414,7 +424,10 @@ init_route(struct route_ipv4 *r,
         r->flags |= RT_METRIC_DEFINED;
     }
 
-    r->flags |= RT_DEFINED;
+    if ((r->flags & RT_DHCP_GATEWAY) == 0)
+    {
+        r->flags |= RT_DEFINED;
+    }
 
     return true;
 
@@ -541,6 +554,16 @@ route_list_add_vpn_gateway(struct route_list *rl,
     rl->spec.remote_endpoint = addr;
     rl->spec.flags |= RTSA_REMOTE_ENDPOINT;
     setenv_route_addr(es, "vpn_gateway", rl->spec.remote_endpoint, -1);
+
+    struct route_ipv4 *r;
+    for (r = rl->routes; r; r = r->next)
+    {
+        if (r->flags & RT_DHCP_GATEWAY)
+        {
+            r->gateway = addr;
+            r->flags |= RT_DEFINED;
+        }
+    }
 }
 
 static void
@@ -611,6 +634,7 @@ bool
 init_route_list(struct route_list *rl,
                 const struct route_option_list *opt,
                 const char *remote_endpoint,
+                bool remote_endpoint_dhcp,
                 int default_metric,
                 in_addr_t remote_host,
                 struct env_set *es)
@@ -676,6 +700,10 @@ init_route_list(struct route_list *rl,
             ret = false;
         }
     }
+    else if (remote_endpoint_dhcp)
+    {
+        rl->spec.flags |= RTSA_DHCP_ENDPOINT;
+    }
 
     if (rl->flags & RG_ENABLE)
     {
diff --git a/src/openvpn/route.h b/src/openvpn/route.h
index 69420228..948c892e 100644
--- a/src/openvpn/route.h
+++ b/src/openvpn/route.h
@@ -62,6 +62,7 @@ struct route_special_addr
 #define RTSA_REMOTE_ENDPOINT  (1<<0)
 #define RTSA_REMOTE_HOST      (1<<1)
 #define RTSA_DEFAULT_METRIC   (1<<2)
+#define RTSA_DHCP_ENDPOINT    (1<<3)
     unsigned int flags;
 
     in_addr_t remote_endpoint;
@@ -112,6 +113,7 @@ struct route_ipv4 {
 #define RT_DEFINED        (1<<0)
 #define RT_ADDED          (1<<1)
 #define RT_METRIC_DEFINED (1<<2)
+#define RT_DHCP_GATEWAY   (1<<3)
     struct route_ipv4 *next;
     unsigned int flags;
     const struct route_option *option;
@@ -280,6 +282,7 @@ void add_route_ipv6_to_option_list(struct route_ipv6_option_list *l,
 bool init_route_list(struct route_list *rl,
                      const struct route_option_list *opt,
                      const char *remote_endpoint,
+                     bool remote_endpoint_dhcp,
                      int default_metric,
                      in_addr_t remote_host,
                      struct env_set *es);
-- 
2.17.1