inet/dhcp: reset network config on dhcp offer

Author: alfreb

api/net/inet.hpp

@@ -83,7 +83,7 @@ namespace net {
                                 typename IPV::addr nmask,
                                 typename IPV::addr gateway,
                                 typename IPV::addr dnssrv = IPV::ADDR_ANY) = 0;
-
+    virtual void reset_config() = 0;
 
     using dhcp_timeout_func = delegate<void(bool timed_out)>;
     virtual void negotiate_dhcp(double timeout = 10.0, dhcp_timeout_func = nullptr) = 0;

api/net/inet4.hpp

@@ -168,6 +168,14 @@ namespace net {
       INFO2("DNS Server: \t%s", dns_server.str().c_str());
     }
 
+    virtual void
+    reset_config() override
+    {
+      this->ip4_addr_ = IP4::ADDR_ANY;
+      this->gateway_ = IP4::ADDR_ANY;
+      this->netmask_ = IP4::ADDR_ANY;
+    }
+
     // register a callback for receiving signal on free packet-buffers
     virtual void
     on_transmit_queue_available(transmit_avail_delg del) override {

src/net/dhcp/dh4client.cpp

@@ -259,14 +259,14 @@ namespace net
     socket.bcast(IP4::ADDR_ANY, DHCP_DEST_PORT, packet, packetlen);
 
     socket.on_read(
-    [this, &socket] (IP4::addr, UDP::port_t port,
+    [this, &socket] (IP4::addr addr, UDP::port_t port,
                      const char* data, size_t len)
     {
       if (port == DHCP_DEST_PORT)
       {
         // we have got a DHCP Offer
-        debug("Received possible DHCP OFFER from %s:%d\n",
-              addr.str().c_str(), DHCP_DEST_PORT);
+        MYINFO("Received possible DHCP OFFER from %s",
+               addr.str().c_str());
         this->offer(socket, data, len);
       }
     });
@@ -369,6 +369,10 @@ namespace net
     if (console_spam)
       MYINFO("DNS SERVER: \t%s", this->dns_server.str().c_str());
 
+    // Remove any existing IP config to be able to receive on broadcast
+    stack.reset_config();
+
+
     // we can accept the offer now by requesting the IP!
     this->request(sock, server_id);
   }