introduce add/del route via interface to route manager

llarp/ev/vpn.hpp

@@ -83,6 +83,12 @@ namespace llarp::vpn
     virtual void
     DelDefaultRouteViaInterface(std::string ifname) = 0;
 
+    virtual void
+    AddRouteViaInterface(std::string ifname, IPRange range) = 0;
+
+    virtual void
+    DelRouteViaInterface(std::string ifname, IPRange range) = 0;
+
     virtual std::vector<IPVariant_t>
     GetGatewaysNotOnInterface(std::string ifname) = 0;
 

llarp/vpn/linux.hpp

@@ -178,14 +178,14 @@ namespace llarp::vpn
       unsigned char bitlen;
       unsigned char data[sizeof(struct in6_addr)];
 
-      _inet_addr(huint32_t addr, int bits = 32)
+      _inet_addr(huint32_t addr, size_t bits = 32)
       {
         family = AF_INET;
         bitlen = bits;
         htobe32buf(data, addr.h);
       }
 
-      _inet_addr(huint128_t addr, int bits = 128)
+      _inet_addr(huint128_t addr, size_t bits = 128)
       {
         family = AF_INET6;
         bitlen = bits;
@@ -313,6 +313,34 @@ namespace llarp::vpn
       }
     }
 
+    void
+    RouteViaInterface(int cmd, int flags, std::string ifname, IPRange range)
+    {
+      int if_idx = if_nametoindex(ifname.c_str());
+      if (range.IsV4())
+      {
+        const auto maybe = GetInterfaceAddr(ifname);
+        if (not maybe)
+          throw std::runtime_error{"we dont have our own network interface?"};
+
+        const _inet_addr gateway{maybe->asIPv4()};
+
+        const _inet_addr addr{
+            net::TruncateV6(range.addr), bits::count_bits(net::TruncateV6(range.netmask_bits))};
+
+        Route(cmd, flags, addr, gateway, GatewayMode::eUpperDefault, if_idx);
+      }
+      else
+      {
+        const auto maybe = GetInterfaceIPv6Address(ifname);
+        if (not maybe)
+          throw std::runtime_error{"we dont have our own network interface?"};
+        const _inet_addr gateway{*maybe, 128};
+        const _inet_addr addr{range.addr, bits::count_bits(range.netmask_bits)};
+        Route(cmd, flags, addr, gateway, GatewayMode::eUpperDefault, if_idx);
+      }
+    }
+
     void
     Route(int cmd, int flags, IPVariant_t ip, IPVariant_t gateway)
     {
@@ -366,6 +394,18 @@ namespace llarp::vpn
       DefaultRouteViaInterface(ifname, RTM_DELROUTE, 0);
     }
 
+    void
+    AddRouteViaInterface(std::string ifname, IPRange range) override
+    {
+      RouteViaInterface(RTM_NEWROUTE, NLM_F_CREATE | NLM_F_EXCL, ifname, range);
+    }
+
+    void
+    DelRouteViaInterface(std::string ifname, IPRange range) override
+    {
+      RouteViaInterface(RTM_DELROUTE, 0, ifname, range);
+    }
+
     std::vector<IPVariant_t>
     GetGatewaysNotOnInterface(std::string ifname) override
     {

llarp/vpn/win32.hpp

@@ -544,6 +544,25 @@ namespace llarp::vpn
       Execute(RouteCommand() + " " + cmd + " 128.0.0.0 MASK 128.0.0.0 " + ifname);
     }
 
+    void
+    RouteViaInterface(std::string ifname, IPRange range, std::string cmd)
+    {
+      if (range.IsV4())
+      {
+        const huint32_t addr4 = net::TruncateV6(range.addr);
+        const huint32_t mask4 = net::TruncateV6(range.netmask_bits);
+        Execute(
+            RouteCommand() + " " + cmd + " " + addr4.ToString() + " MASK " + mask4.ToString() + " "
+            + ifname);
+      }
+      else
+      {
+        Execute(
+            RouteCommand() + " " + cmd + range.addr.ToString() + " MASK "
+            + range.netmask_bits.ToString() + " " + ifname);
+      }
+    }
+
    public:
     void
     AddRoute(IPVariant_t ip, IPVariant_t gateway) override
@@ -557,6 +576,18 @@ namespace llarp::vpn
       Route(ip, gateway, "DELETE");
     }
 
+    void
+    AddRouteViaInterface(std::string ifname, IPRange range) override
+    {
+      RouteViaInterface(ifname, range, "ADD");
+    }
+
+    void
+    DelRouteViaInterface(std::string ifname, IPRange range) override
+    {
+      RouteViaInterface(ifname, range, "DELETE");
+    }
+
     void
     AddBlackhole() override{};