Merge bitcoin/bitcoin#26145: [24.x] init: abort if i2p/cjdns are chosen via -onlynet but are unreachable

68209a7b5c0326e14508d9cf749771605bd6ffe7 rpc: make addpeeraddress work with cjdns addresses (Martin Zumsande)
a8a9ed67cc447d204304ccfd844c45fd76486c6a init: Abort if i2p/cjdns are chosen via -onlynet but unreachable (Martin Zumsande)

Pull request description:

  Identical commit from https://github.com/bitcoin/bitcoin/pull/25989

ACKs for top commit:
  fanquake:
    ACK 68209a7b5c0326e14508d9cf749771605bd6ffe7

Tree-SHA512: eec335df06b4c209cfe3473cb623828effd00c45a5dd605bb920edd265de1c789627482b005a51e89b8fc79cc4c5d26ff1fc306f2e4573897c5c7f083aa22861

4 files changed, 23 insertions, 1 deletions

diff --git a/src/init.cpp b/src/init.cpp
index ad894f7f11..25b40c6c6e 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -1285,6 +1285,11 @@ bool AppInitMain(NodeContext& node, interfaces::BlockAndHeaderTipInfo* tip_info)
     }
 
     if (!args.IsArgSet("-cjdnsreachable")) {
+        if (args.IsArgSet("-onlynet") && IsReachable(NET_CJDNS)) {
+            return InitError(
+                _("Outbound connections restricted to CJDNS (-onlynet=cjdns) but "
+                  "-cjdnsreachable is not provided"));
+        }
         SetReachable(NET_CJDNS, false);
     }
     // Now IsReachable(NET_CJDNS) is true if:
@@ -1757,6 +1762,11 @@ bool AppInitMain(NodeContext& node, interfaces::BlockAndHeaderTipInfo* tip_info)
         }
         SetProxy(NET_I2P, Proxy{addr});
     } else {
+        if (args.IsArgSet("-onlynet") && IsReachable(NET_I2P)) {
+            return InitError(
+                _("Outbound connections restricted to i2p (-onlynet=i2p) but "
+                  "-i2psam is not provided"));
+        }
         SetReachable(NET_I2P, false);
     }
 
diff --git a/src/net.h b/src/net.h
index 66a228b3ec..044701a339 100644
--- a/src/net.h
+++ b/src/net.h
@@ -164,6 +164,7 @@ bool SeenLocal(const CService& addr);
 bool IsLocal(const CService& addr);
 bool GetLocal(CService &addr, const CNetAddr *paddrPeer = nullptr);
 CService GetLocalAddress(const CNetAddr& addrPeer);
+CService MaybeFlipIPv6toCJDNS(const CService& service);
 
 
 extern bool fDiscover;
diff --git a/src/rpc/net.cpp b/src/rpc/net.cpp
index e221b3462d..d701a180ab 100644
--- a/src/rpc/net.cpp
+++ b/src/rpc/net.cpp
@@ -947,7 +947,8 @@ static RPCHelpMan addpeeraddress()
     bool success{false};
 
     if (LookupHost(addr_string, net_addr, false)) {
-        CAddress address{{net_addr, port}, ServiceFlags{NODE_NETWORK | NODE_WITNESS}};
+        CService service{net_addr, port};
+        CAddress address{MaybeFlipIPv6toCJDNS(service), ServiceFlags{NODE_NETWORK | NODE_WITNESS}};
         address.nTime = Now<NodeSeconds>();
         // The source address is set equal to the address. This is equivalent to the peer
         // announcing itself.
diff --git a/test/functional/feature_proxy.py b/test/functional/feature_proxy.py
index d02d56d068..c90852562e 100755
--- a/test/functional/feature_proxy.py
+++ b/test/functional/feature_proxy.py
@@ -332,6 +332,16 @@ class ProxyTest(BitcoinTestFramework):
         msg = "Error: Invalid -i2psam address or hostname: 'def:xyz'"
         self.nodes[1].assert_start_raises_init_error(expected_msg=msg)
 
+        self.log.info("Test passing invalid -onlynet=i2p without -i2psam raises expected init error")
+        self.nodes[1].extra_args = ["-onlynet=i2p"]
+        msg = "Error: Outbound connections restricted to i2p (-onlynet=i2p) but -i2psam is not provided"
+        self.nodes[1].assert_start_raises_init_error(expected_msg=msg)
+
+        self.log.info("Test passing invalid -onlynet=cjdns without -cjdnsreachable raises expected init error")
+        self.nodes[1].extra_args = ["-onlynet=cjdns"]
+        msg = "Error: Outbound connections restricted to CJDNS (-onlynet=cjdns) but -cjdnsreachable is not provided"
+        self.nodes[1].assert_start_raises_init_error(expected_msg=msg)
+
         self.log.info("Test passing -onlynet=onion with -onion=0/-noonion raises expected init error")
         msg = (
             "Error: Outbound connections restricted to Tor (-onlynet=onion) but "