headscale/protocol_common.go
2022-08-15 23:35:06 +02:00

86 lines
2.4 KiB
Go

package headscale
import (
"encoding/json"
"net/http"
"strconv"
"github.com/rs/zerolog/log"
"tailscale.com/tailcfg"
)
const (
// The CapabilityVersion is used by Tailscale clients to indicate
// their codebase version. Tailscale clients can communicate over TS2021
// from CapabilityVersion 28, but we only have good support for it
// since https://github.com/tailscale/tailscale/pull/4323 (Noise in any HTTPS port).
//
// Related to this change, there is https://github.com/tailscale/tailscale/pull/5379,
// where CapabilityVersion 39 is introduced to indicate #4323 was merged.
//
// See also https://github.com/tailscale/tailscale/blob/main/tailcfg/tailcfg.go
NoiseCapabilityVersion = 39
)
// KeyHandler provides the Headscale pub key
// Listens in /key.
func (h *Headscale) KeyHandler(
writer http.ResponseWriter,
req *http.Request,
) {
// New Tailscale clients send a 'v' parameter to indicate the CurrentCapabilityVersion
clientCapabilityStr := req.URL.Query().Get("v")
if clientCapabilityStr != "" {
log.Debug().
Str("handler", "/key").
Str("v", clientCapabilityStr).
Msg("New noise client")
clientCapabilityVersion, err := strconv.Atoi(clientCapabilityStr)
if err != nil {
writer.Header().Set("Content-Type", "text/plain; charset=utf-8")
writer.WriteHeader(http.StatusBadRequest)
_, err := writer.Write([]byte("Wrong params"))
if err != nil {
log.Error().
Caller().
Err(err).
Msg("Failed to write response")
}
return
}
if clientCapabilityVersion >= NoiseCapabilityVersion {
// Tailscale has a different key for the TS2021 protocol
resp := tailcfg.OverTLSPublicKeyResponse{
LegacyPublicKey: h.privateKey.Public(),
PublicKey: h.noisePrivateKey.Public(),
}
writer.Header().Set("Content-Type", "application/json")
writer.WriteHeader(http.StatusOK)
err = json.NewEncoder(writer).Encode(resp)
if err != nil {
log.Error().
Caller().
Err(err).
Msg("Failed to write response")
}
return
}
}
log.Debug().
Str("handler", "/key").
Msg("New legacy client")
// Old clients don't send a 'v' parameter, so we send the legacy public key
writer.Header().Set("Content-Type", "text/plain; charset=utf-8")
writer.WriteHeader(http.StatusOK)
_, err := writer.Write([]byte(MachinePublicKeyStripPrefix(h.privateKey.Public())))
if err != nil {
log.Error().
Caller().
Err(err).
Msg("Failed to write response")
}
}