// NewTrafficRulesSet initializes a TrafficRulesSet with
// the rules data in the specified config file.
func NewTrafficRulesSet(filename string) (*TrafficRulesSet, error) {
set := &TrafficRulesSet{}
set.ReloadableFile = common.NewReloadableFile(
filename,
func(filename string) error {
configJSON, err := ioutil.ReadFile(filename)
if err != nil {
// On error, state remains the same
return common.ContextError(err)
}
var newSet TrafficRulesSet
err = json.Unmarshal(configJSON, &newSet)
if err != nil {
return common.ContextError(err)
}
err = newSet.Validate()
if err != nil {
return common.ContextError(err)
}
// Modify actual traffic rules only after validation
set.DefaultRules = newSet.DefaultRules
set.FilteredRules = newSet.FilteredRules
return nil
})
_, err := set.Reload()
if err != nil {
return nil, common.ContextError(err)
}
return set, nil
}
// NewDatabase initializes a Database, calling Reload on the specified
// filename.
func NewDatabase(filename string) (*Database, error) {
database := &Database{}
database.ReloadableFile = common.NewReloadableFile(
filename,
func(filename string) error {
psinetJSON, err := ioutil.ReadFile(filename)
if err != nil {
// On error, state remains the same
return common.ContextError(err)
}
err = json.Unmarshal(psinetJSON, &database)
if err != nil {
// On error, state remains the same
// (Unmarshal first validates the provided
// JOSN and then populates the interface)
return common.ContextError(err)
}
return nil
})
_, err := database.Reload()
if err != nil {
return nil, common.ContextError(err)
}
return database, nil
}
// NewDNSResolver initializes a new DNSResolver, loading it with
// a fresh resolver value. The load must succeed, so either
// "/etc/resolv.conf" must contain a valid "nameserver" line with
// a DNS server IP address, or a valid "defaultResolver" default
// value must be provided.
// On systems without "/etc/resolv.conf", "defaultResolver" is
// required.
//
// The resolver is considered stale and reloaded if last checked
// more than 5 seconds before the last Get(), which is similar to
// frequencies in other implementations:
//
// - https://golang.org/src/net/dnsclient_unix.go,
// resolverConfig.tryUpdate: 5 seconds
//
// - https://github.com/ambrop72/badvpn/blob/master/udpgw/udpgw.c,
// maybe_update_dns: 2 seconds
//
func NewDNSResolver(defaultResolver string) (*DNSResolver, error) {
dns := &DNSResolver{
lastReloadTime: int64(monotime.Now()),
}
dns.ReloadableFile = common.NewReloadableFile(
DNS_SYSTEM_CONFIG_FILENAME,
func(fileContent []byte) error {
resolver, err := parseResolveConf(fileContent)
if err != nil {
// On error, state remains the same
return common.ContextError(err)
}
dns.resolver = resolver
log.WithContextFields(
LogFields{
"resolver": resolver.String(),
}).Debug("loaded system DNS resolver")
return nil
})
_, err := dns.Reload()
if err != nil {
if defaultResolver == "" {
return nil, common.ContextError(err)
}
log.WithContextFields(
LogFields{"err": err}).Info(
"failed to load system DNS resolver; using default")
resolver, err := parseResolver(defaultResolver)
if err != nil {
return nil, common.ContextError(err)
}
dns.resolver = resolver
}
return dns, nil
}
// NewGeoIPService initializes a new GeoIPService.
func NewGeoIPService(
databaseFilenames []string,
discoveryValueHMACKey string) (*GeoIPService, error) {
geoIP := &GeoIPService{
databases: make([]*geoIPDatabase, len(databaseFilenames)),
sessionCache: cache.New(GEOIP_SESSION_CACHE_TTL, 1*time.Minute),
discoveryValueHMACKey: discoveryValueHMACKey,
}
for i, filename := range databaseFilenames {
database := &geoIPDatabase{}
database.ReloadableFile = common.NewReloadableFile(
filename,
func(filename string) error {
maxMindReader, err := maxminddb.Open(filename)
if err != nil {
// On error, database state remains the same
return common.ContextError(err)
}
if database.maxMindReader != nil {
database.maxMindReader.Close()
}
database.maxMindReader = maxMindReader
return nil
})
_, err := database.Reload()
if err != nil {
return nil, common.ContextError(err)
}
geoIP.databases[i] = database
}
return geoIP, nil
}
// NewConfig initializes a Config with the settings in the specified
// file.
func NewConfig(filename string) (*Config, error) {
config := &Config{}
config.ReloadableFile = common.NewReloadableFile(
filename,
func(fileContent []byte) error {
newConfig, err := LoadConfig(fileContent)
if err != nil {
return common.ContextError(err)
}
// Modify actual traffic rules only after validation
config.Schemes = newConfig.Schemes
return nil
})
_, err := config.Reload()
if err != nil {
return nil, common.ContextError(err)
}
return config, nil
}