fix empty config case (#1400)

* fix empty config case

* * fix case for empty ifname / ifaddr on relay
* bail if no dns server bound

* use AssignmentAcceptor

llarp/config/config.cpp

@@ -480,16 +480,7 @@ namespace llarp
             "Interface name for lokinet traffic. If unset lokinet will look for a free name",
             "lokinetN, starting at 0 (e.g. lokinet0, lokinet1, ...).",
         },
-        [this](std::string arg) {
-          if (arg.empty())
-          {
-            const auto maybe = llarp::FindFreeTun();
-            if (not maybe)
-              throw std::invalid_argument("cannot determine free interface name");
-            arg = *maybe;
-          }
-          m_ifname = arg;
-        });
+        AssignmentAcceptor(m_ifname));
 
     conf.defineOption<std::string>(
         "network",
@@ -500,17 +491,9 @@ namespace llarp
             "lokinet will attempt to find an unused private range.",
         },
         [this](std::string arg) {
-          if (arg.empty())
-          {
-            const auto maybe = llarp::FindFreeRange();
-            if (not maybe)
-              throw std::invalid_argument("cannot determine free ip range");
-            m_ifaddr = *maybe;
-            return;
-          }
           if (not m_ifaddr.FromString(arg))
           {
-            throw std::invalid_argument(stringify("[network]:ifaddr invalid value: ", arg));
+            throw std::invalid_argument(stringify("[network]:ifaddr invalid value: '", arg, "'"));
           }
         });
 

llarp/dns/server.cpp

@@ -49,10 +49,7 @@ namespace llarp
       LogicCall(m_ClientLogic, [=]() {
         llarp_ev_add_udp(self->m_ClientLoop.get(), &self->m_Client, any.createSockAddr());
       });
-      LogicCall(m_ServerLogic, [=]() {
-        llarp_ev_add_udp(self->m_ServerLoop.get(), &self->m_Server, addr.createSockAddr());
-      });
-      return true;
+      return llarp_ev_add_udp(self->m_ServerLoop.get(), &self->m_Server, addr.createSockAddr());
     }
 
     static Proxy::Buffer_t

llarp/handlers/exit.cpp

@@ -551,6 +551,13 @@ namespace llarp
       m_UpstreamResolvers = dnsConfig.m_upstreamDNS;
 
       m_OurRange = networkConfig.m_ifaddr;
+      if (!m_OurRange.addr.h)
+      {
+        const auto maybe = llarp::FindFreeRange();
+        if (not maybe.has_value())
+          throw std::runtime_error("cannot find free interface range");
+        m_OurRange = *maybe;
+      }
       const auto host_str = m_OurRange.BaseAddressString();
       // string, or just a plain char array?
       strncpy(m_Tun.ifaddr, host_str.c_str(), sizeof(m_Tun.ifaddr) - 1);
@@ -570,12 +577,19 @@ namespace llarp
           m_HigestAddr);
       m_UseV6 = not m_OurRange.IsV4();
 
-      if (networkConfig.m_ifname.length() >= sizeof(m_Tun.ifname))
+      std::string ifname = networkConfig.m_ifname;
+      if (ifname.empty())
+      {
+        const auto maybe = llarp::FindFreeTun();
+        if (not maybe.has_value())
+          throw std::runtime_error("cannot find free interface name");
+        ifname = *maybe;
+      }
+      if (ifname.length() >= sizeof(m_Tun.ifname))
       {
-        throw std::invalid_argument(
-            stringify(Name() + " ifname '", networkConfig.m_ifname, "' is too long"));
+        throw std::invalid_argument(stringify(Name() + " ifname '", ifname, "' is too long"));
       }
-      strncpy(m_Tun.ifname, networkConfig.m_ifname.c_str(), sizeof(m_Tun.ifname) - 1);
+      strncpy(m_Tun.ifname, ifname.c_str(), sizeof(m_Tun.ifname) - 1);
       LogInfo(Name(), " set ifname to ", m_Tun.ifname);
 
       // TODO: "exit-whitelist" and "exit-blacklist"

llarp/handlers/tun.cpp

@@ -199,6 +199,13 @@ namespace llarp
       }
 
       std::string ifname = conf.m_ifname;
+      if (ifname.empty())
+      {
+        const auto maybe = llarp::FindFreeTun();
+        if (not maybe.has_value())
+          throw std::runtime_error("cannot find free interface name");
+        ifname = *maybe;
+      }
       if (tunif)
       {
         if (ifname.length() >= sizeof(tunif->ifname))
@@ -210,6 +217,16 @@ namespace llarp
         llarp::LogInfo(Name() + " setting ifname to ", tunif->ifname);
 
         m_OurRange = conf.m_ifaddr;
+        if (!m_OurRange.addr.h)
+        {
+          const auto maybe = llarp::FindFreeRange();
+          if (not maybe.has_value())
+          {
+            throw std::runtime_error("cannot find free address range");
+          }
+          m_OurRange = *maybe;
+        }
+
         m_UseV6 = not m_OurRange.IsV4();
         tunif->netmask = m_OurRange.HostmaskBits();
         const auto addr = m_OurRange.BaseAddressString();