feat(net): IP resolution in docker (#10681)

Co-authored-by: Cody Wang <cody.wang@coinbase.com>

Cargo.lock

@@ -3845,6 +3845,16 @@ dependencies = [
  "unicode-normalization",
 ]
 
+[[package]]
+name = "if-addrs"
+version = "0.13.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a78a89907582615b19f6f0da1af18abf6ff08be259395669b834b057a7ee92d8"
+dependencies = [
+ "libc",
+ "windows-sys 0.52.0",
+]
+
 [[package]]
 name = "impl-codec"
 version = "0.6.0"
@@ -7435,6 +7445,7 @@ name = "reth-net-nat"
 version = "1.0.6"
 dependencies = [
  "futures-util",
+ "if-addrs",
  "reqwest",
  "reth-tracing",
  "serde_with",

Cargo.toml

@@ -536,6 +536,7 @@ tower-http = "0.5"
 
 # p2p
 discv5 = "0.7.0"
+if-addrs = "0.13"
 
 # rpc
 jsonrpsee = "0.24"

book/cli/reth/debug/execution.md

@@ -228,6 +228,11 @@ Networking:
 
           [default: 25600]
 
+      --net-if.experimental <IF_NAME>
+          Name of network interface used to communicate with peers.
+
+          If flag is set, but no value is passed, the default interface for docker `eth0` is tried.
+
       --to <TO>
           The maximum block height
 

book/cli/reth/debug/in-memory-merkle.md

@@ -228,6 +228,11 @@ Networking:
 
           [default: 25600]
 
+      --net-if.experimental <IF_NAME>
+          Name of network interface used to communicate with peers.
+
+          If flag is set, but no value is passed, the default interface for docker `eth0` is tried.
+
       --retries <RETRIES>
           The number of retries per request
 

book/cli/reth/debug/merkle.md

@@ -228,6 +228,11 @@ Networking:
 
           [default: 25600]
 
+      --net-if.experimental <IF_NAME>
+          Name of network interface used to communicate with peers.
+
+          If flag is set, but no value is passed, the default interface for docker `eth0` is tried.
+
       --retries <RETRIES>
           The number of retries per request
 

book/cli/reth/debug/replay-engine.md

@@ -228,6 +228,11 @@ Networking:
 
           [default: 25600]
 
+      --net-if.experimental <IF_NAME>
+          Name of network interface used to communicate with peers.
+
+          If flag is set, but no value is passed, the default interface for docker `eth0` is tried.
+
       --engine-api-store <PATH>
           The path to read engine API messages from
 

book/cli/reth/node.md

@@ -220,6 +220,11 @@ Networking:
 
           [default: 25600]
 
+      --net-if.experimental <IF_NAME>
+          Name of network interface used to communicate with peers.
+
+          If flag is set, but no value is passed, the default interface for docker `eth0` is tried.
+
 RPC:
       --http
           Enable the HTTP-RPC server

book/cli/reth/p2p.md

@@ -205,6 +205,11 @@ Networking:
 
           [default: 25600]
 
+      --net-if.experimental <IF_NAME>
+          Name of network interface used to communicate with peers.
+
+          If flag is set, but no value is passed, the default interface for docker `eth0` is tried.
+
 Datadir:
       --datadir <DATA_DIR>
           The path to the data dir for all reth files and subdirectories.

book/cli/reth/stage/run.md

@@ -271,6 +271,11 @@ Networking:
 
           [default: 25600]
 
+      --net-if.experimental <IF_NAME>
+          Name of network interface used to communicate with peers.
+
+          If flag is set, but no value is passed, the default interface for docker `eth0` is tried.
+
 Logging:
       --log.stdout.format <FORMAT>
           The format to use for logs written to stdout

book/cli/reth/stage/unwind.md

@@ -233,6 +233,11 @@ Networking:
 
           [default: 25600]
 
+      --net-if.experimental <IF_NAME>
+          Name of network interface used to communicate with peers.
+
+          If flag is set, but no value is passed, the default interface for docker `eth0` is tried.
+
       --offline
           If this is enabled, then all stages except headers, bodies, and sender recovery will be unwound
 

crates/net/nat/Cargo.toml

@@ -17,6 +17,7 @@ reqwest.workspace = true
 serde_with = { workspace = true, optional = true }
 thiserror.workspace = true
 tokio = { workspace = true, features = ["time"] }
+if-addrs.workspace = true
 
 [dev-dependencies]
 reth-tracing.workspace = true

crates/net/nat/src/lib.rs

@@ -12,6 +12,10 @@
 #![cfg_attr(not(test), warn(unused_crate_dependencies))]
 #![cfg_attr(docsrs, feature(doc_cfg, doc_auto_cfg))]
 
+pub mod net_if;
+
+pub use net_if::{NetInterfaceError, DEFAULT_NET_IF_NAME};
+
 use std::{
     fmt,
     future::{poll_fn, Future},

crates/net/nat/src/net_if.rs

@@ -0,0 +1,55 @@
+//! IP resolution on non-host Docker network.
+
+#![cfg(not(target_os = "windows"))]
+
+use std::{io, net::IpAddr};
+
+/// The 'eth0' interface tends to be the default interface that docker containers use to
+/// communicate with each other.
+pub const DEFAULT_NET_IF_NAME: &str = "eth0";
+
+/// Errors resolving network interface IP.
+#[derive(Debug, thiserror::Error)]
+pub enum NetInterfaceError {
+    /// Error reading OS interfaces.
+    #[error("failed to read OS interfaces: {0}")]
+    Io(io::Error),
+    /// No interface found with given name.
+    #[error("interface not found: {0}, found other interfaces: {1:?}")]
+    IFNotFound(String, Vec<String>),
+}
+
+/// Reads IP of OS interface with given name, if exists.
+#[cfg(not(target_os = "windows"))]
+pub fn resolve_net_if_ip(if_name: &str) -> Result<IpAddr, NetInterfaceError> {
+    match if_addrs::get_if_addrs() {
+        Ok(ifs) => {
+            let ip = ifs.iter().find(|i| i.name == if_name).map(|i| i.ip());
+            match ip {
+                Some(ip) => Ok(ip),
+                None => {
+                    let ifs = ifs.into_iter().map(|i| i.name.as_str().into()).collect();
+                    Err(NetInterfaceError::IFNotFound(if_name.into(), ifs))
+                }
+            }
+        }
+        Err(err) => Err(NetInterfaceError::Io(err)),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use std::net::Ipv4Addr;
+
+    use super::*;
+
+    #[test]
+    fn read_docker_if_addr() {
+        const LOCALHOST_IF: [&str; 2] = ["lo0", "lo"];
+
+        let ip = resolve_net_if_ip(LOCALHOST_IF[0])
+            .unwrap_or_else(|_| resolve_net_if_ip(LOCALHOST_IF[1]).unwrap());
+
+        assert_eq!(ip, Ipv4Addr::LOCALHOST);
+    }
+}

crates/node/core/src/args/network.rs

@@ -15,7 +15,7 @@ use reth_discv5::{
     discv5::ListenConfig, DEFAULT_COUNT_BOOTSTRAP_LOOKUPS, DEFAULT_DISCOVERY_V5_PORT,
     DEFAULT_SECONDS_BOOTSTRAP_LOOKUP_INTERVAL, DEFAULT_SECONDS_LOOKUP_INTERVAL,
 };
-use reth_net_nat::NatResolver;
+use reth_net_nat::{NatResolver, DEFAULT_NET_IF_NAME};
 use reth_network::{
     transactions::{
         constants::{
@@ -35,6 +35,7 @@ use reth_network::{
 };
 use reth_network_peers::{mainnet_nodes, TrustedPeer};
 use secp256k1::SecretKey;
+use tracing::error;
 
 use crate::version::P2P_CLIENT_VERSION;
 
@@ -148,9 +149,38 @@ pub struct NetworkArgs {
     /// Max capacity of cache of hashes for transactions pending fetch.
     #[arg(long = "max-tx-pending-fetch", value_name = "COUNT", default_value_t = DEFAULT_MAX_CAPACITY_CACHE_PENDING_FETCH, verbatim_doc_comment)]
     pub max_capacity_cache_txns_pending_fetch: u32,
+
+    /// Name of network interface used to communicate with peers.
+    ///
+    /// If flag is set, but no value is passed, the default interface for docker `eth0` is tried.
+    #[cfg(not(target_os = "windows"))]
+    #[arg(long = "net-if.experimental", conflicts_with = "addr", value_name = "IF_NAME")]
+    pub net_if: Option<String>,
 }
 
 impl NetworkArgs {
+    /// Returns the resolved IP address.
+    pub fn resolved_addr(&self) -> IpAddr {
+        #[cfg(not(target_os = "windows"))]
+        if let Some(ref if_name) = self.net_if {
+            let if_name = if if_name.is_empty() { DEFAULT_NET_IF_NAME } else { if_name };
+            return match reth_net_nat::net_if::resolve_net_if_ip(if_name) {
+                Ok(addr) => addr,
+                Err(err) => {
+                    error!(target: "reth::cli",
+                        if_name,
+                        %err,
+                        "Failed to read network interface IP"
+                    );
+
+                    DEFAULT_DISCOVERY_ADDR
+                }
+            }
+        }
+
+        self.addr
+    }
+
     /// Returns the resolved bootnodes if any are provided.
     pub fn resolved_bootnodes(&self) -> Option<Vec<NodeRecord>> {
         self.bootnodes.clone().map(|bootnodes| {
@@ -176,6 +206,7 @@ impl NetworkArgs {
         secret_key: SecretKey,
         default_peers_file: PathBuf,
     ) -> NetworkConfigBuilder {
+        let addr = self.resolved_addr();
         let chain_bootnodes = self
             .resolved_bootnodes()
             .unwrap_or_else(|| chain_spec.bootnodes().unwrap_or_else(mainnet_nodes));
@@ -224,11 +255,11 @@ impl NetworkArgs {
             })
             // apply discovery settings
             .apply(|builder| {
-                let rlpx_socket = (self.addr, self.port).into();
+                let rlpx_socket = (addr, self.port).into();
                 self.discovery.apply_to_builder(builder, rlpx_socket, chain_bootnodes)
             })
             .listener_addr(SocketAddr::new(
-                self.addr, // set discovery port based on instance number
+                addr, // set discovery port based on instance number
                 self.port,
             ))
             .discovery_addr(SocketAddr::new(
@@ -303,6 +334,7 @@ impl Default for NetworkArgs {
             max_pending_pool_imports: DEFAULT_MAX_COUNT_PENDING_POOL_IMPORTS,
             max_seen_tx_history: DEFAULT_MAX_COUNT_TRANSACTIONS_SEEN_BY_PEER,
             max_capacity_cache_txns_pending_fetch: DEFAULT_MAX_CAPACITY_CACHE_PENDING_FETCH,
+            net_if: None,
         }
     }
 }