mirrors_public/schollz_croc
1
1
Fork 0
mirror of https://github.com/schollz/croc.git synced 2025-10-11 05:11:06 +02:00
Code Activity

Merge pull request #737 from schollz:schollz/issue735

Browse source 
fix: croc hangs with broken dns
This commit is contained in:
Zack 2024-06-13 08:28:06 -07:00 • committed by GitHub
commit 1e34537bb2
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
1 changed files with 23 additions and 3 deletions
Download patch file Download diff file Expand all files Collapse all files

26
src/models/constants.go
View file

@ -6,8 +6,10 @@ import (
"net" "net"
"os" "os"
"path" "path"
"time"
"github.com/schollz/croc/v10/src/utils" "github.com/schollz/croc/v10/src/utils"
log "github.com/schollz/logger"
) )
// TCP_BUFFER_SIZE is the maximum packet size // TCP_BUFFER_SIZE is the maximum packet size
@ -54,6 +56,8 @@ func getConfigFile(requireValidPath bool) (fname string, err error) {
} }
func init() { func init() {
log.SetLevel("info")
log.SetOutput(os.Stderr)
doRemember := false doRemember := false
for _, flag := range os.Args { for _, flag := range os.Args {
if flag == "--internal-dns" { if flag == "--internal-dns" {
@ -78,6 +82,7 @@ func init() {
INTERNAL_DNS = utils.Exists(fname) INTERNAL_DNS = utils.Exists(fname)
} }
} }
log.Trace("Using internal DNS: ", INTERNAL_DNS)
var err error var err error
var addr string var addr string
addr, err = lookup(DEFAULT_RELAY) addr, err = lookup(DEFAULT_RELAY)
@ -86,17 +91,20 @@ func init() {
} else { } else {
DEFAULT_RELAY = "" DEFAULT_RELAY = ""
} }
log.Tracef("Default ipv4 relay: %s", addr)
addr, err = lookup(DEFAULT_RELAY6) addr, err = lookup(DEFAULT_RELAY6)
if err == nil { if err == nil {
DEFAULT_RELAY6 = net.JoinHostPort(addr, DEFAULT_PORT) DEFAULT_RELAY6 = net.JoinHostPort(addr, DEFAULT_PORT)
} else { } else {
DEFAULT_RELAY6 = "" DEFAULT_RELAY6 = ""
} }
log.Tracef("Default ipv6 relay: %s", addr)
} }
// Resolve a hostname to an IP address using DNS. // Resolve a hostname to an IP address using DNS.
func lookup(address string) (ipaddress string, err error) { func lookup(address string) (ipaddress string, err error) {
if !INTERNAL_DNS { if !INTERNAL_DNS {
log.Tracef("Using local DNS to resolve %s", address)
return localLookupIP(address) return localLookupIP(address)
} }
type Result struct { type Result struct {
@ -108,11 +116,13 @@ func lookup(address string) (ipaddress string, err error) {
go func(dns string) { go func(dns string) {
var r Result var r Result
r.s, r.err = remoteLookupIP(address, dns) r.s, r.err = remoteLookupIP(address, dns)
log.Tracef("Resolved %s to %s using %s", address, r.s, dns)
result <- r result <- r
}(dns) }(dns)
} }
for i := 0; i < len(publicDNS); i++ { for i := 0; i < len(publicDNS); i++ {
ipaddress = (<-result).s ipaddress = (<-result).s
log.Tracef("Resolved %s to %s", address, ipaddress)
if ipaddress != "" { if ipaddress != "" {
return return
} }
@ -121,9 +131,16 @@ func lookup(address string) (ipaddress string, err error) {
return return
} }
// localLookupIP returns a host's IP address based on the local resolver. // localLookupIP returns a host's IP address using the local DNS configuration.
func localLookupIP(address string) (ipaddress string, err error) { func localLookupIP(address string) (ipaddress string, err error) {
ip, err := net.LookupHost(address) // Create a context with a 500 millisecond timeout
ctx, cancel := context.WithTimeout(context.Background(), 500*time.Millisecond)
defer cancel()
r := &net.Resolver{}
// Use the context with timeout in the LookupHost function
ip, err := r.LookupHost(ctx, address)
if err != nil { if err != nil {
return return
} }
@ -133,6 +150,9 @@ func localLookupIP(address string) (ipaddress string, err error) {
// remoteLookupIP returns a host's IP address based on a remote DNS server. // remoteLookupIP returns a host's IP address based on a remote DNS server.
func remoteLookupIP(address, dns string) (ipaddress string, err error) { func remoteLookupIP(address, dns string) (ipaddress string, err error) {
ctx, cancel := context.WithTimeout(context.Background(), 500*time.Millisecond)
defer cancel()
r := &net.Resolver{ r := &net.Resolver{
PreferGo: true, PreferGo: true,
Dial: func(ctx context.Context, network, _ string) (net.Conn, error) { Dial: func(ctx context.Context, network, _ string) (net.Conn, error) {
@ -140,7 +160,7 @@ func remoteLookupIP(address, dns string) (ipaddress string, err error) {
return d.DialContext(ctx, network, dns+":53") return d.DialContext(ctx, network, dns+":53")
}, },
} }
ip, err := r.LookupHost(context.Background(), address) ip, err := r.LookupHost(ctx, address)
if err != nil { if err != nil {
return return
} }