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add panic handlers #25

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add panic handlers #25

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27 changes: 24 additions & 3 deletions client.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,8 @@ import (
"fmt"
"math/rand"
"net"
"os"
"runtime/debug"
"strings"
"time"

Expand Down Expand Up @@ -108,7 +110,7 @@ func applyOpts(options ...ClientOption) clientOpts {
return conf
}

func (c *client) run(ctx context.Context, params *lookupParams) error {
func (c *client) run(ctx context.Context, params *lookupParams) (err error) {
ctx, cancel := context.WithCancel(ctx)
done := make(chan struct{})
go func() {
Expand All @@ -118,7 +120,7 @@ func (c *client) run(ctx context.Context, params *lookupParams) error {

// If previous probe was ok, it should be fine now. In case of an error later on,
// the entries' queue is closed.
err := c.periodicQuery(ctx, params)
err = c.periodicQuery(ctx, params)
cancel()
<-done
return err
Expand Down Expand Up @@ -165,6 +167,12 @@ var cleanupFreq = 10 * time.Second

// Start listeners and waits for the shutdown signal from exit channel
func (c *client) mainloop(ctx context.Context, params *lookupParams) {
defer func() {
if rerr := recover(); rerr != nil {
fmt.Fprintf(os.Stderr, "caught panic: %s\n%s\n", rerr, debug.Stack())
}
}()

// start listening for responses
msgCh := make(chan *dns.Msg, 32)
if c.ipv4conn != nil {
Expand Down Expand Up @@ -313,6 +321,12 @@ func (c *client) shutdown() {
// Data receiving routine reads from connection, unpacks packets into dns.Msg
// structures and sends them to a given msgCh channel
func (c *client) recv(ctx context.Context, l interface{}, msgCh chan *dns.Msg) {
defer func() {
if rerr := recover(); rerr != nil {
fmt.Fprintf(os.Stderr, "caught panic: %s\n%s\n", rerr, debug.Stack())
}
}()

var readFrom func([]byte) (n int, src net.Addr, err error)

switch pConn := l.(type) {
Expand Down Expand Up @@ -408,7 +422,14 @@ func (c *client) periodicQuery(ctx context.Context, params *lookupParams) error

// Performs the actual query by service name (browse) or service instance name (lookup),
// start response listeners goroutines and loops over the entries channel.
func (c *client) query(params *lookupParams) error {
func (c *client) query(params *lookupParams) (err error) {
defer func() {
if rerr := recover(); rerr != nil {
fmt.Fprintf(os.Stderr, "caught panic: %s\n%s\n", rerr, debug.Stack())
err = fmt.Errorf("panic in zeroconf query: %s", rerr)
}
}()

var serviceName, serviceInstanceName string
serviceName = fmt.Sprintf("%s.%s.", trimDot(params.Service), trimDot(params.Domain))

Expand Down
18 changes: 16 additions & 2 deletions server.go
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Original file line number Diff line number Diff line change
Expand Up @@ -6,6 +6,7 @@ import (
"math/rand"
"net"
"os"
"runtime/debug"
"strings"
"sync"
"time"
Expand Down Expand Up @@ -309,7 +310,14 @@ func (s *Server) recv6(c *ipv6.PacketConn) {
}

// parsePacket is used to parse an incoming packet
func (s *Server) parsePacket(packet []byte, ifIndex int, from net.Addr) error {
func (s *Server) parsePacket(packet []byte, ifIndex int, from net.Addr) (err error) {
defer func() {
if rerr := recover(); rerr != nil {
fmt.Fprintf(os.Stderr, "caught panic: %s\n%s\n", rerr, debug.Stack())
err = fmt.Errorf("panic in mDNS packet handling: %s", rerr)
}
}()

var msg dns.Msg
if err := msg.Unpack(packet); err != nil {
// log.Printf("[ERR] zeroconf: Failed to unpack packet: %v", err)
Expand Down Expand Up @@ -548,8 +556,14 @@ func (s *Server) serviceTypeName(resp *dns.Msg, ttl uint32) {
}

// Perform probing & announcement
//TODO: implement a proper probing & conflict resolution
// TODO: implement a proper probing & conflict resolution
func (s *Server) probe() {
defer func() {
if rerr := recover(); rerr != nil {
fmt.Fprintf(os.Stderr, "caught panic: %s\n%s\n", rerr, debug.Stack())
}
}()

defer s.refCount.Done()

q := new(dns.Msg)
Expand Down