allow blocking whole subnets

src/net/error.h

@@ -42,7 +42,8 @@ namespace net
         invalid_i2p_address,
         invalid_port,       //!< Outside of 0-65535 range
         invalid_tor_address,//!< Invalid base32 or length
-        unsupported_address //!< Type not supported by `get_network_address`
+        unsupported_address,//!< Type not supported by `get_network_address`
+        invalid_mask,       //!< Outside of 0-32 range
     };
 
     //! \return `std::error_category` for `net` namespace.

src/net/parse.cpp

@@ -58,4 +58,27 @@ namespace net
             return {epee::net_utils::ipv4_network_address{ip, port}};
         return make_error_code(net::error::unsupported_address);
     }
+
+    expect<epee::net_utils::ipv4_network_subnet>
+    get_ipv4_subnet_address(const boost::string_ref address, bool allow_implicit_32)
+    {
+        uint32_t mask = 32;
+        const boost::string_ref::size_type slash = address.find_first_of('/');
+        if (slash != boost::string_ref::npos)
+        {
+            if (!epee::string_tools::get_xtype_from_string(mask, std::string{address.substr(slash + 1)}))
+                return make_error_code(net::error::invalid_mask);
+            if (mask > 32)
+                return make_error_code(net::error::invalid_mask);
+        }
+        else if (!allow_implicit_32)
+            return make_error_code(net::error::invalid_mask);
+
+        std::uint32_t ip = 0;
+        boost::string_ref S(address.data(), slash != boost::string_ref::npos ? slash : address.size());
+        if (!epee::string_tools::get_ip_int32_from_string(ip, std::string(S)))
+            return make_error_code(net::error::invalid_host);
+
+        return {epee::net_utils::ipv4_network_subnet{ip, (uint8_t)mask}};
+    }
 }

src/net/parse.h

@@ -50,5 +50,18 @@ namespace net
     */
     expect<epee::net_utils::network_address>
         get_network_address(boost::string_ref address, std::uint16_t default_port);
+
+    /*!
+      Identifies an IPv4 subnet in CIDR notatioa and returns it as a generic
+      `network_address`. If the type is unsupported, it might be a hostname,
+      and `error() == net::error::kUnsupportedAddress` is returned.
+
+      \param address An ipv4 address.
+      \param allow_implicit_32 whether to accept "raw" IPv4 addresses, with CIDR notation
+
+      \return A tor or IPv4 address, else error.
+    */
+    expect<epee::net_utils::ipv4_network_subnet>
+        get_ipv4_subnet_address(boost::string_ref address, bool allow_implicit_32 = false);
 }