Add derived links endpoint from LLDP and SNMP data.

Build link views from LLDP neighbors and resolve targets by matching remote system names to SNMP sysName entries.

Made-with: Cursor

internal/api/handler.go

@@ -15,6 +15,16 @@ type Handler struct {
 	run   *scans.Runner
 }
 
+type LinkView struct {
+	SourceIP       string `json:"source_ip"`
+	SourcePort     string `json:"source_port"`
+	TargetIP       string `json:"target_ip,omitempty"`
+	TargetSysName  string `json:"target_sys_name,omitempty"`
+	TargetPort     string `json:"target_port,omitempty"`
+	RemoteChassis  string `json:"remote_chassis_id,omitempty"`
+	ResolvedBy     string `json:"resolved_by"`
+}
+
 func NewHandler(store scans.Store, run *scans.Runner) *Handler {
 	return &Handler{store: store, run: run}
 }
@@ -29,6 +39,7 @@ func (h *Handler) Routes() http.Handler {
 	mux.HandleFunc("GET /api/scans/{id}/ports", h.getScanPorts)
 	mux.HandleFunc("GET /api/scans/{id}/snmp", h.getScanSNMP)
 	mux.HandleFunc("GET /api/scans/{id}/lldp", h.getScanLLDP)
+	mux.HandleFunc("GET /api/scans/{id}/links", h.getScanLinks)
 	return withJSON(mux)
 }
 
@@ -202,6 +213,69 @@ func (h *Handler) getScanLLDP(w http.ResponseWriter, r *http.Request) {
 	})
 }
 
+func (h *Handler) getScanLinks(w http.ResponseWriter, r *http.Request) {
+	id := r.PathValue("id")
+	if id == "" {
+		writeError(w, http.StatusBadRequest, "scan id is required")
+		return
+	}
+	if _, ok := h.store.GetScan(id); !ok {
+		writeError(w, http.StatusNotFound, "scan not found")
+		return
+	}
+
+	limit := 2000
+	if raw := r.URL.Query().Get("limit"); raw != "" {
+		n, err := strconv.Atoi(raw)
+		if err != nil || n <= 0 || n > 20000 {
+			writeError(w, http.StatusBadRequest, "limit must be between 1 and 20000")
+			return
+		}
+		limit = n
+	}
+
+	snmpItems := h.store.ListSNMPResults(id, 10000)
+	lldpItems := h.store.ListLLDPResults(id, limit)
+
+	sysNameToIP := make(map[string]string, len(snmpItems))
+	for _, s := range snmpItems {
+		name := strings.TrimSpace(strings.ToLower(s.SysName))
+		if name == "" {
+			continue
+		}
+		if _, exists := sysNameToIP[name]; !exists {
+			sysNameToIP[name] = s.IP
+		}
+	}
+
+	links := make([]LinkView, 0, len(lldpItems))
+	for _, l := range lldpItems {
+		targetNameNorm := strings.TrimSpace(strings.ToLower(l.RemoteSysName))
+		targetIP := ""
+		resolvedBy := "unresolved"
+		if targetNameNorm != "" {
+			if ip, ok := sysNameToIP[targetNameNorm]; ok {
+				targetIP = ip
+				resolvedBy = "remote_sys_name"
+			}
+		}
+
+		links = append(links, LinkView{
+			SourceIP:      l.IP,
+			SourcePort:    l.LocalPortNum,
+			TargetIP:      targetIP,
+			TargetSysName: l.RemoteSysName,
+			TargetPort:    l.RemotePortID,
+			RemoteChassis: l.RemoteChassisID,
+			ResolvedBy:    resolvedBy,
+		})
+	}
+
+	writeJSON(w, http.StatusOK, map[string]any{
+		"items": links,
+	})
+}
+
 func withJSON(next http.Handler) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set("Content-Type", "application/json; charset=utf-8")