Add /ip/<ip> route that redirects to prefix detail page

- Implement handleIPRedirect handler that looks up the prefix containing an IP
- Add /ip/{ip} route to routes.go
- Reuse existing GetASInfoForIP database method which returns prefix info
- Redirect to /prefix/<prefix> page with HTTP 303 See Other status
- Handle invalid IPs (400) and IPs with no route (404)

internal/server/handlers.go

@@ -616,3 +616,33 @@ func (s *Server) handlePrefixDetail() http.HandlerFunc {
 		}
 	}
 }
+
+// handleIPRedirect looks up the prefix containing the IP and redirects to its detail page
+func (s *Server) handleIPRedirect() http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		ip := chi.URLParam(r, "ip")
+		if ip == "" {
+			http.Error(w, "IP parameter is required", http.StatusBadRequest)
+
+			return
+		}
+
+		// Look up AS information for the IP (which includes the prefix)
+		asInfo, err := s.db.GetASInfoForIP(ip)
+		if err != nil {
+			if errors.Is(err, database.ErrInvalidIP) {
+				http.Error(w, "Invalid IP address", http.StatusBadRequest)
+			} else if errors.Is(err, database.ErrNoRoute) {
+				http.Error(w, "No route found for this IP", http.StatusNotFound)
+			} else {
+				s.logger.Error("Failed to look up IP", "error", err)
+				http.Error(w, "Internal server error", http.StatusInternalServerError)
+			}
+
+			return
+		}
+
+		// Redirect to the prefix detail page
+		http.Redirect(w, r, "/prefix/"+asInfo.Prefix, http.StatusSeeOther)
+	}
+}

internal/server/routes.go

@@ -28,6 +28,7 @@ func (s *Server) setupRoutes() {
 	// AS and prefix detail pages
 	r.Get("/as/{asn}", s.handleASDetail())
 	r.Get("/prefix/{prefix}", s.handlePrefixDetail())
+	r.Get("/ip/{ip}", s.handleIPRedirect())
 
 	// API routes
 	r.Route("/api/v1", func(r chi.Router) {