GH-525: Toggle for entry_dns

USER-INTERFACE-INTERFACE.md

@@ -1143,6 +1143,7 @@ be cleared.
 * `db-password` - Password to unlock the sensitive values in the database.
 * `dns-servers` - Comma-separated list of DNS servers to use.
 * `earning-wallet` - Wallet into which earnings should be deposited.
+* `entry-dns` - To start MASQ's local DNS server if HTTP proxying is unavailable.
 * `gas-price` - The fee per unit of computational effort in blockchain transactions, measured in gwei.
 * `ip` - The public IP address of the Node.
 * `log-level` - The lowest level of logs that should be recorded. `off`, `error`, `warn`, `info`, `debug`, `trace`

masq_lib/src/shared_schema.rs

@@ -50,6 +50,10 @@ pub const EARNING_WALLET_HELP: &str =
      (case-insensitive). If you already have a derivation-path earning wallet, don't supply this. \
      If you have supplied an earning wallet address before, either don't supply it again or be \
      careful to supply exactly the same one you supplied before.";
+pub const ENTRY_DNS_HELP: &str = "Specify whether to use entry DNS. If you can't use HTTP proxying \
+     to reroute your client's traffic through MASQ's Node, you can specify --entry-dns to start up \
+     MASQ's local DNS server; but you will also need to subvert your network stack's DNS traffic \
+     using dns_utility. This practice is not recommended but may be necessary in certain situations.";
 pub const IP_ADDRESS_HELP: &str = "The public IP address of your MASQ Node: that is, the IPv4 \
      address at which other Nodes can contact yours. If you're running your Node behind \
      a router, this will be the IP address of the router. If this IP address starts with 192.168 or 10.0, \
@@ -408,6 +412,14 @@ pub fn shared_app(head: App<'static, 'static>) -> App<'static, 'static> {
         EARNING_WALLET_HELP,
         common_validators::validate_ethereum_address,
     ))
+    .arg(
+        Arg::with_name("entry-dns")
+            .long("entry-dns")
+            .value_name("ENTRY-DNS")
+            .required(false)
+            .takes_value(false)
+            .help(ENTRY_DNS_HELP),
+    )
     .arg(
         Arg::with_name("fake-public-key")
             .long("fake-public-key")
@@ -741,6 +753,13 @@ mod tests {
              If you have supplied an earning wallet address before, either don't supply it again or be \
              careful to supply exactly the same one you supplied before."
         );
+        assert_eq!(
+            ENTRY_DNS_HELP,
+            "Specify whether to use entry DNS. If you can't use HTTP proxying \
+             to reroute your client's traffic through MASQ's Node, you can specify --entry-dns to start up \
+             MASQ's local DNS server; but you will also need to subvert your network stack's DNS traffic \
+             using dns_utility. This practice is not recommended but may be necessary in certain situations."
+        );
         assert_eq!(
             IP_ADDRESS_HELP,
             "The public IP address of your MASQ Node: that is, the IPv4 \

node/src/node_configurator/unprivileged_parse_args_configuration.rs

@@ -37,7 +37,7 @@ pub trait UnprivilegedParseArgsConfiguration {
         unprivileged_config
             .blockchain_bridge_config
             .blockchain_service_url_opt =
-            if is_user_specified(multi_config, "blockchain-service-url") {
+            if has_user_specified(multi_config, "blockchain-service-url") {
                 value_m!(multi_config, "blockchain-service-url", String)
             } else {
                 match persistent_config.blockchain_service_url() {
@@ -48,7 +48,7 @@ pub trait UnprivilegedParseArgsConfiguration {
             };
         unprivileged_config.clandestine_port_opt = value_m!(multi_config, "clandestine-port", u16);
         unprivileged_config.blockchain_bridge_config.gas_price =
-            if is_user_specified(multi_config, "gas-price") {
+            if has_user_specified(multi_config, "gas-price") {
                 value_m!(multi_config, "gas-price", u64).expectv("gas price")
             } else {
                 match persistent_config.gas_price() {
@@ -614,7 +614,7 @@ fn set_db_password_at_first_mention(
     }
 }
 
-fn is_user_specified(multi_config: &MultiConfig, parameter: &str) -> bool {
+pub fn has_user_specified(multi_config: &MultiConfig, parameter: &str) -> bool {
     multi_config.occurrences_of(parameter) > 0
 }