From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Mon, 26 Jul 2021 18:35:59 +0000 (+0100)
Subject: config: check batch vs mtu sizes
X-Git-Tag: hippotat/1.0.0~437
X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ian/git?a=commitdiff_plain;h=0e082f759fe1399c918d8bf0a3d89ec2ccbed2a0;p=hippotat.git

config: check batch vs mtu sizes

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---

diff --git a/src/config.rs b/src/config.rs
index 5243e8b..cc754a5 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -663,6 +663,18 @@ impl InstanceConfig {
       )?;
     }
 
+    let check_batch = {
+      let mtu = self.mtu;
+      move |max_batch, key| {
+        if max_batch/2 < mtu {
+          throw!(anyhow!("max batch {:?} ({}) must be >= 2 x mtu ({}) \
+                          (to allow for SLIP ESC-encoding)",
+                         key, max_batch, mtu))
+        }
+        Ok::<_,AE>(())
+      }
+    };
+
     match end {
       LinkEnd::Client => {
         if &self.url == &default::<Uri>() {
@@ -681,12 +693,15 @@ impl InstanceConfig {
             })
             .parse().unwrap()
         }
+
+        check_batch(self.max_batch_up, "max_batch_up")?;
       },
 
       LinkEnd::Server => {
         if self.addrs.is_empty() {
           throw!(anyhow!("missing 'addrs' setting"))
         }
+        check_batch(self.max_batch_down, "max_batch_down")?;
       },
     }