rpc: don't try to run some rpcs if in ibd

Some RPCs timeout if we try to make them while on IBD, and this gets the
RPC server stuck forever. This commit forbids running them during IBD,
and return an error.

florestad/src/json_rpc/server.rs

@@ -103,6 +103,15 @@ impl Rpc for RpcImpl {
                     .any(|input| input.previous_output == expected_input)
             })
         }
+
+        if self.chain.is_in_idb() {
+            return Err(jsonrpc_core::Error {
+                code: Error::InInitialBlockDownload.into(),
+                message: Error::InInitialBlockDownload.to_string(),
+                data: None,
+            });
+        }
+
         // can't proceed without block filters
         if self.block_filter_storage.is_none() {
             return Err(jsonrpc_core::Error {
@@ -175,6 +184,14 @@ impl Rpc for RpcImpl {
     }
 
     fn add_node(&self, node: String) -> Result<bool> {
+        if self.chain.is_in_idb() {
+            return Err(jsonrpc_core::Error {
+                code: Error::InInitialBlockDownload.into(),
+                message: Error::InInitialBlockDownload.to_string(),
+                data: None,
+            });
+        }
+
         let node = node.split(':').collect::<Vec<&str>>();
         let (ip, port) = if node.len() == 2 {
             (node[0], node[1].parse().map_err(|_| Error::InvalidPort)?)
@@ -368,9 +385,18 @@ impl Rpc for RpcImpl {
     }
 
     fn get_block(&self, hash: BlockHash, verbosity: Option<u8>) -> Result<Value> {
+        let is_genesis = self.chain.get_block_hash(0).unwrap().eq(&hash);
+        if self.chain.is_in_idb() && !is_genesis {
+            return Err(jsonrpc_core::Error {
+                code: Error::InInitialBlockDownload.into(),
+                message: Error::InInitialBlockDownload.to_string(),
+                data: None,
+            });
+        }
+
         let verbosity = verbosity.unwrap_or(1);
 
-        let block = if self.chain.get_block_hash(0).unwrap().eq(&hash) {
+        let block = if is_genesis {
             Some(genesis_block(self.network))
         } else {
             self.node.get_block(hash).map_err(|_| Error::Chain)?
@@ -438,6 +464,14 @@ impl Rpc for RpcImpl {
     }
 
     fn get_peer_info(&self) -> Result<Vec<PeerInfo>> {
+        if self.chain.is_in_idb() {
+            return Err(jsonrpc_core::Error {
+                code: Error::InInitialBlockDownload.into(),
+                message: Error::InInitialBlockDownload.to_string(),
+                data: None,
+            });
+        }
+
         let peers = self.node.get_peer_info();
         if let Ok(peers) = peers {
             return Ok(peers);