swarm: changes taken unjudged, dropped (REFUSALS)

A node refusing changes a peer brought tells it which broke a rule; the
peer judges them itself, and if its rules refuse them too, drops them
with all built on them (its document forked without them, a fresh
actor), quarantining its own writes among them. Wire version 42.

Auth plan M6 (rejoin on taint).

1 files changed, 11 insertions, 2 deletions

diff --git a/src/transport/wire.rs b/src/transport/wire.rs
index 88b2916..7ff7835 100644
--- a/src/transport/wire.rs
+++ b/src/transport/wire.rs
@@ -14,7 +14,7 @@ use super::{EncodedMessage, MessageKind, ParsedMessage};
 
 /// The wire format's version, the first byte of every payload. Bump it with every change
 /// to a message type or a codec (`golden_bytes` fails then).
-pub(crate) const VERSION: u8 = 41;
+pub(crate) const VERSION: u8 = 42;
 
 /// What the second byte of a payload says.
 fn tag(kind: MessageKind) -> u8 {
@@ -37,6 +37,7 @@ fn tag(kind: MessageKind) -> u8 {
         MessageKind::NeighbourReply => 17,
         MessageKind::Disconnect => 18,
         MessageKind::Signatures => 19,
+        MessageKind::Refusals => 20,
     }
 }
 
@@ -99,6 +100,7 @@ pub(crate) fn encode(message: &ParsedMessage) -> Result<Vec<u8>, WireError> {
             rmp_serde::encode::write(&mut payload, answer)?
         }
         ParsedMessage::Signatures(message) => rmp_serde::encode::write(&mut payload, message)?,
+        ParsedMessage::Refusals(message) => rmp_serde::encode::write(&mut payload, message)?,
     }
     Ok(payload)
 }
@@ -180,6 +182,8 @@ pub(crate) fn decode(payload: &[u8]) -> Result<ParsedMessage, WireError> {
         ParsedMessage::Disconnect(rmp_serde::from_slice(body)?)
     } else if is(MessageKind::Signatures) {
         ParsedMessage::Signatures(rmp_serde::from_slice(body)?)
+    } else if is(MessageKind::Refusals) {
+        ParsedMessage::Refusals(rmp_serde::from_slice(body)?)
     } else {
         return Err(WireError::UnknownKind(kind));
     })
@@ -544,6 +548,11 @@ pub(crate) fn samples() -> Vec<ParsedMessage> {
             epoch_seq: 1,
             signatures: serde_bytes::ByteBuf::from(vec![9; 96]),
         }),
+        ParsedMessage::Refusals(crate::transport::RefusalsMessage {
+            epoch,
+            epoch_seq: 1,
+            changes: vec![crate::document::ChangeHash([7; 32])],
+        }),
     ]
 }
 
@@ -575,7 +584,7 @@ mod tests {
     #[test]
     fn every_kind_round_trips() {
         let samples = samples();
-        assert_eq!(samples.len(), 18, "a kind is missing from `samples`");
+        assert_eq!(samples.len(), 19, "a kind is missing from `samples`");
         for message in samples {
             let bytes = encode(&message).unwrap();
             let decoded = decode(&bytes).unwrap();