tomswallapi/internal/server/nat.go

package server

import (
	"net/http"
	"strconv"

	"github.com/go-chi/chi/v5"

	"git.unkin.net/unkin/tomswallapi/internal/model"
)

// mountNAT wires the NAT-tier resources (snat/masquerade, netmap, 1:1 nat).
func (s *Server) mountNAT(r chi.Router) {
	r.Route("/snat", func(r chi.Router) {
		r.Get("/", s.listSNAT)
		r.Post("/", s.createSNAT)
		r.Get("/{id}", s.getSNAT)
		r.Delete("/{id}", s.deleteSNAT)
	})
	r.Route("/netmap", func(r chi.Router) {
		r.Get("/", s.listNetmap)
		r.Post("/", s.createNetmap)
		r.Get("/{id}", s.getNetmap)
		r.Delete("/{id}", s.deleteNetmap)
	})
	r.Route("/nat", func(r chi.Router) {
		r.Get("/", s.listNAT)
		r.Post("/", s.createNAT)
		r.Get("/{id}", s.getNAT)
		r.Delete("/{id}", s.deleteNAT)
	})
}

func idParam(w http.ResponseWriter, r *http.Request) (int64, bool) {
	id, err := strconv.ParseInt(chi.URLParam(r, "id"), 10, 64)
	if err != nil {
		writeError(w, http.StatusBadRequest, "id must be an integer")
		return 0, false
	}
	return id, true
}

// ---- SNAT ------------------------------------------------------------------

func (s *Server) listSNAT(w http.ResponseWriter, r *http.Request) {
	list, err := s.store.ListSNAT(r.Context())
	respondList(w, list, err)
}

func (s *Server) createSNAT(w http.ResponseWriter, r *http.Request) {
	var v model.SNATRule
	if !decode(w, r, &v) {
		return
	}
	if v.Action != "masquerade" && v.Action != "snat" {
		writeError(w, http.StatusBadRequest, "action must be masquerade or snat")
		return
	}
	id, err := s.store.CreateSNAT(r.Context(), v)
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	v.ID = id
	writeJSON(w, http.StatusCreated, v)
}

func (s *Server) getSNAT(w http.ResponseWriter, r *http.Request) {
	id, ok := idParam(w, r)
	if !ok {
		return
	}
	v, err := s.store.GetSNAT(r.Context(), id)
	respondOne(w, v, err)
}

func (s *Server) deleteSNAT(w http.ResponseWriter, r *http.Request) {
	id, ok := idParam(w, r)
	if !ok {
		return
	}
	respondDelete(w, s.store.DeleteSNAT(r.Context(), id))
}

// ---- Netmap ----------------------------------------------------------------

func (s *Server) listNetmap(w http.ResponseWriter, r *http.Request) {
	list, err := s.store.ListNetmap(r.Context())
	respondList(w, list, err)
}

func (s *Server) createNetmap(w http.ResponseWriter, r *http.Request) {
	var v model.NetmapRule
	if !decode(w, r, &v) {
		return
	}
	if v.Type != "dnat" && v.Type != "snat" {
		writeError(w, http.StatusBadRequest, "type must be dnat or snat")
		return
	}
	id, err := s.store.CreateNetmap(r.Context(), v)
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	v.ID = id
	writeJSON(w, http.StatusCreated, v)
}

func (s *Server) getNetmap(w http.ResponseWriter, r *http.Request) {
	id, ok := idParam(w, r)
	if !ok {
		return
	}
	v, err := s.store.GetNetmap(r.Context(), id)
	respondOne(w, v, err)
}

func (s *Server) deleteNetmap(w http.ResponseWriter, r *http.Request) {
	id, ok := idParam(w, r)
	if !ok {
		return
	}
	respondDelete(w, s.store.DeleteNetmap(r.Context(), id))
}

// ---- 1:1 NAT ---------------------------------------------------------------

func (s *Server) listNAT(w http.ResponseWriter, r *http.Request) {
	list, err := s.store.ListNAT(r.Context())
	respondList(w, list, err)
}

func (s *Server) createNAT(w http.ResponseWriter, r *http.Request) {
	var v model.NATRule
	if !decode(w, r, &v) {
		return
	}
	if v.Device == "" || v.External == "" || v.Internal == "" {
		writeError(w, http.StatusBadRequest, "device, external, and internal are required")
		return
	}
	id, err := s.store.CreateNAT(r.Context(), v)
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	v.ID = id
	writeJSON(w, http.StatusCreated, v)
}

func (s *Server) getNAT(w http.ResponseWriter, r *http.Request) {
	id, ok := idParam(w, r)
	if !ok {
		return
	}
	v, err := s.store.GetNAT(r.Context(), id)
	respondOne(w, v, err)
}

func (s *Server) deleteNAT(w http.ResponseWriter, r *http.Request) {
	id, ok := idParam(w, r)
	if !ok {
		return
	}
	respondDelete(w, s.store.DeleteNAT(r.Context(), id))
}