headscale/derp.go
2021-11-14 16:46:09 +01:00

165 lines
3.4 KiB
Go

package headscale
import (
"context"
"encoding/json"
"io"
"io/ioutil"
"net/http"
"net/url"
"os"
"time"
"github.com/rs/zerolog/log"
"gopkg.in/yaml.v2"
"tailscale.com/tailcfg"
)
func loadDERPMapFromPath(path string) (*tailcfg.DERPMap, error) {
derpFile, err := os.Open(path)
if err != nil {
return nil, err
}
defer derpFile.Close()
var derpMap tailcfg.DERPMap
b, err := io.ReadAll(derpFile)
if err != nil {
return nil, err
}
err = yaml.Unmarshal(b, &derpMap)
return &derpMap, err
}
func loadDERPMapFromURL(addr url.URL) (*tailcfg.DERPMap, error) {
ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
defer cancel()
req, err := http.NewRequestWithContext(ctx, "GET", addr.String(), nil)
if err != nil {
return nil, err
}
client := http.Client{
Timeout: 10 * time.Second,
}
resp, err := client.Do(req)
if err != nil {
return nil, err
}
defer resp.Body.Close()
body, err := ioutil.ReadAll(resp.Body)
if err != nil {
return nil, err
}
var derpMap tailcfg.DERPMap
err = json.Unmarshal(body, &derpMap)
return &derpMap, err
}
// mergeDERPMaps naively merges a list of DERPMaps into a single
// DERPMap, it will _only_ look at the Regions, an integer.
// If a region exists in two of the given DERPMaps, the region
// form the _last_ DERPMap will be preserved.
// An empty DERPMap list will result in a DERPMap with no regions.
func mergeDERPMaps(derpMaps []*tailcfg.DERPMap) *tailcfg.DERPMap {
result := tailcfg.DERPMap{
OmitDefaultRegions: false,
Regions: map[int]*tailcfg.DERPRegion{},
}
for _, derpMap := range derpMaps {
for id, region := range derpMap.Regions {
result.Regions[id] = region
}
}
return &result
}
func GetDERPMap(cfg DERPConfig) *tailcfg.DERPMap {
derpMaps := make([]*tailcfg.DERPMap, 0)
for _, path := range cfg.Paths {
log.Debug().
Str("func", "GetDERPMap").
Str("path", path).
Msg("Loading DERPMap from path")
derpMap, err := loadDERPMapFromPath(path)
if err != nil {
log.Error().
Str("func", "GetDERPMap").
Str("path", path).
Err(err).
Msg("Could not load DERP map from path")
break
}
derpMaps = append(derpMaps, derpMap)
}
for _, addr := range cfg.URLs {
derpMap, err := loadDERPMapFromURL(addr)
log.Debug().
Str("func", "GetDERPMap").
Str("url", addr.String()).
Msg("Loading DERPMap from path")
if err != nil {
log.Error().
Str("func", "GetDERPMap").
Str("url", addr.String()).
Err(err).
Msg("Could not load DERP map from path")
break
}
derpMaps = append(derpMaps, derpMap)
}
derpMap := mergeDERPMaps(derpMaps)
log.Trace().Interface("derpMap", derpMap).Msg("DERPMap loaded")
if len(derpMap.Regions) == 0 {
log.Warn().
Msg("DERP map is empty, not a single DERP map datasource was loaded correctly or contained a region")
}
return derpMap
}
func (h *Headscale) scheduledDERPMapUpdateWorker(cancelChan <-chan struct{}) {
log.Info().
Dur("frequency", h.cfg.DERP.UpdateFrequency).
Msg("Setting up a DERPMap update worker")
ticker := time.NewTicker(h.cfg.DERP.UpdateFrequency)
for {
select {
case <-cancelChan:
return
case <-ticker.C:
log.Info().Msg("Fetching DERPMap updates")
h.DERPMap = GetDERPMap(h.cfg.DERP)
namespaces, err := h.ListNamespaces()
if err != nil {
log.Error().
Err(err).
Msg("Failed to fetch namespaces")
}
for _, namespace := range namespaces {
h.setLastStateChangeToNow(namespace.Name)
}
}
}
}