From d6ab8e6653ebd763bdb34d12e4cd349e9008def0 Mon Sep 17 00:00:00 2001
From: Jake McGinty <me@jake.su>
Date: Mon, 14 Jun 2021 23:05:59 +0900
Subject: [PATCH] shared(wg): default to 1400 if network CIDR is IPv6

Second fix for #102
---
 shared/src/types.rs | 6 +++---
 shared/src/wg.rs    | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/shared/src/types.rs b/shared/src/types.rs
index fb028a6..4950647 100644
--- a/shared/src/types.rs
+++ b/shared/src/types.rs
@@ -385,9 +385,9 @@ pub struct NetworkOpt {
     /// If not set, innernet will auto-select based on availability.
     pub backend: Backend,
 
-    #[structopt(long, default_value = "1420")]
-    /// Specify the desired MTU for your interface.
-    pub mtu: u32,
+    #[structopt(long)]
+    /// Specify the desired MTU for your interface (default: 1420 for IPv4 and 1400 for IPv6).
+    pub mtu: Option<u32>,
 }
 
 #[derive(Debug, Clone, Deserialize, Serialize, PartialEq)]
diff --git a/shared/src/wg.rs b/shared/src/wg.rs
index 7a54952..40386a4 100644
--- a/shared/src/wg.rs
+++ b/shared/src/wg.rs
@@ -85,7 +85,7 @@ pub fn up(
         .set_private_key(wgctrl::Key::from_base64(&private_key).unwrap())
         .apply(interface, network.backend)?;
     set_addr(interface, address)?;
-    set_up(interface, network.mtu)?;
+    set_up(interface, network.mtu.unwrap_or_else(|| if address.is_ipv4() { 1420 } else { 1400 }))?;
     if !network.no_routing {
         add_route(interface, address)?;
     }