Changed to accept a CIDR address and use net.IP

* In general we'll have an IP address and a subnet mask for the weave
   network address; account for this in the zone DB and in the HTTP
   server.

 * Use the net.IP type rather than string, which gives us a bit more
   generality (in theory it'll deal with Ipv6 too) and validation (we
   attempt to parse the input)

server/http.go

@@ -3,6 +3,7 @@ package weavedns
 import (
 	"fmt"
 	"log"
+	"net"
 	"net/http"
 )
 
@@ -14,12 +15,20 @@ func ListenHttp(db Zone) {
 	http.HandleFunc("/add", func(w http.ResponseWriter, r *http.Request) {
 		name := r.FormValue("name")
 		addr := r.FormValue("ip")
-		weave_ip := r.FormValue("weave_ip")
-		if name != "" && addr != "" && weave_ip != "" {
-			log.Printf("Adding %s, %s, %s", name, addr, weave_ip)
-			db.AddRecord(name, addr, weave_ip)
+		weave_cidr := r.FormValue("weave_cidr")
+		if name != "" && addr != "" && weave_cidr != "" {
+			ip := net.ParseIP(addr)
+			weave_ip, subnet, err := net.ParseCIDR(weave_cidr)
+			if err == nil && ip != nil {
+				log.Printf("Adding %s (%s) -> %s", name, addr, weave_cidr)
+				db.AddRecord(name, ip, weave_ip, subnet)
+			} else if err != nil {
+				log.Printf("Invalid CIDR in request: %s", weave_cidr)
+			} else {
+				log.Printf("Invalid IP in request: %s", addr)
+			}
 		} else {
-			log.Printf("Invalid request: %s, %s, %s", name, addr, weave_ip)
+			log.Printf("Invalid request: %s, %s, %s", name, addr, weave_cidr)
 		}
 	})
 	address := fmt.Sprintf(":%d", UPDATE_PORT)