Xray-core/features/routing/dns/context.go
2021-03-19 23:35:01 +08:00

72 lines
2.1 KiB
Go

package dns
//go:generate go run github.com/xtls/xray-core/common/errors/errorgen
import (
"github.com/xtls/xray-core/common/net"
"github.com/xtls/xray-core/features/dns"
"github.com/xtls/xray-core/features/routing"
)
// ResolvableContext is an implementation of routing.Context, with domain resolving capability.
type ResolvableContext struct {
routing.Context
dnsClient dns.Client
resolvedIPs []net.IP
}
// GetTargetIPs overrides original routing.Context's implementation.
func (ctx *ResolvableContext) GetTargetIPs() []net.IP {
if ips := ctx.Context.GetTargetIPs(); len(ips) != 0 {
return ips
}
if len(ctx.resolvedIPs) > 0 {
return ctx.resolvedIPs
}
if domain := ctx.GetTargetDomain(); len(domain) != 0 {
var lookupFunc func(string) ([]net.IP, error) = ctx.dnsClient.LookupIP
ipOption := &dns.IPOption{
IPv4Enable: true,
IPv6Enable: true,
}
if c, ok := ctx.dnsClient.(dns.ClientWithIPOption); ok {
ipOption = c.GetIPOption()
c.SetFakeDNSOption(false) // Skip FakeDNS.
} else {
newError("ctx.dnsClient doesn't implement ClientWithIPOption").AtDebug().WriteToLog()
}
switch {
case ipOption.IPv4Enable && !ipOption.IPv6Enable:
if lookupIPv4, ok := ctx.dnsClient.(dns.IPv4Lookup); ok {
lookupFunc = lookupIPv4.LookupIPv4
} else {
newError("ctx.dnsClient doesn't implement IPv4Lookup. Use LookupIP instead.").AtDebug().WriteToLog()
}
case !ipOption.IPv4Enable && ipOption.IPv6Enable:
if lookupIPv6, ok := ctx.dnsClient.(dns.IPv6Lookup); ok {
lookupFunc = lookupIPv6.LookupIPv6
} else {
newError("ctx.dnsClient doesn't implement IPv6Lookup. Use LookupIP instead.").AtDebug().WriteToLog()
}
}
ips, err := lookupFunc(domain)
if err == nil {
ctx.resolvedIPs = ips
return ips
}
newError("resolve ip for ", domain).Base(err).WriteToLog()
}
return nil
}
// ContextWithDNSClient creates a new routing context with domain resolving capability.
// Resolved domain IPs can be retrieved by GetTargetIPs().
func ContextWithDNSClient(ctx routing.Context, client dns.Client) routing.Context {
return &ResolvableContext{Context: ctx, dnsClient: client}
}