rpc: Prevents adding the same ip more than once when formatted differently

Currently it is possible to add the same node twice when formatting IPs in
different, yet equivalent, manner. This applies to both ipv4 and ipv6, e.g:

127.0.0.1 = 127.1 | [::1] = [0:0:0:0:0:0:0:1]

`addnode` will accept both and display both as connected (given they translate to
the same IP). This will not result in multiple connections to the same node, but
will report redundant info when querying `getaddednodeinfo` and populate `m_added_nodes`
with redundant data.

This can be avoided performing comparing the contents of `m_added_addr` and the address
to be added as `CServices` instead of as strings.

Author: sr-gi

src/net.cpp

@@ -3471,9 +3471,12 @@ std::vector<CAddress> CConnman::GetAddresses(CNode& requestor, size_t max_addres
 
 bool CConnman::AddNode(const AddedNodeParams& add)
 {
+    const CService resolved(LookupNumeric(add.m_added_node, GetDefaultPort(add.m_added_node)));
+    const bool resolved_is_valid{resolved.IsValid()};
+
     LOCK(m_added_nodes_mutex);
     for (const auto& it : m_added_node_params) {
-        if (add.m_added_node == it.m_added_node) return false;
+        if (add.m_added_node == it.m_added_node || (resolved_is_valid && resolved == LookupNumeric(it.m_added_node, GetDefaultPort(it.m_added_node)))) return false;
     }
 
     m_added_node_params.push_back(add);

test/functional/rpc_net.py

@@ -215,8 +215,11 @@ def test_addnode_getaddednodeinfo(self):
         # add a node (node2) to node0
         ip_port = "127.0.0.1:{}".format(p2p_port(2))
         self.nodes[0].addnode(node=ip_port, command='add')
+        # try to add an equivalent ip
+        ip_port2 = "127.1:{}".format(p2p_port(2))
+        assert_raises_rpc_error(-23, "Node already added", self.nodes[0].addnode, node=ip_port2, command='add')
         # check that the node has indeed been added
-        added_nodes = self.nodes[0].getaddednodeinfo(ip_port)
+        added_nodes = self.nodes[0].getaddednodeinfo()
         assert_equal(len(added_nodes), 1)
         assert_equal(added_nodes[0]['addednode'], ip_port)
         # check that node cannot be added again