commit 1d76d3ca2e581bbb345b09444dd1d25dd985673c
Author: Cecylia Bocovich <[email protected]>
Date: Fri May 10 17:16:35 2019 -0400
Implement limitedRead function for client side
MaxBytesReader is only documented for server side reads, so we're using
a local limitedRead function instead that uses an io.LimitedReader.
Declared limits in a commented constant
---
broker/broker.go | 7 ++++---
client/lib/rendezvous.go | 21 ++++++++++++++++++++-
proxy-go/snowflake.go | 21 ++++++++++++++++++++-
3 files changed, 44 insertions(+), 5 deletions(-)
diff --git a/broker/broker.go b/broker/broker.go
index a0ef38a..274d87c 100644
--- a/broker/broker.go
+++ b/broker/broker.go
@@ -28,6 +28,7 @@ import (
const (
ClientTimeout = 10
ProxyTimeout = 10
+ readLimit = 100000 //Maximum number of bytes to be read from an
HTTP request
)
type BrokerContext struct {
@@ -136,7 +137,7 @@ For snowflake proxies to request a client from the Broker.
*/
func proxyPolls(ctx *BrokerContext, w http.ResponseWriter, r *http.Request) {
id := r.Header.Get("X-Session-ID")
- body, err := ioutil.ReadAll(http.MaxBytesReader(w, r.Body, 100000))
+ body, err := ioutil.ReadAll(http.MaxBytesReader(w, r.Body, readLimit))
if nil != err {
log.Println("Invalid data.")
w.WriteHeader(http.StatusBadRequest)
@@ -166,7 +167,7 @@ the HTTP response back to the client.
*/
func clientOffers(ctx *BrokerContext, w http.ResponseWriter, r *http.Request) {
startTime := time.Now()
- offer, err := ioutil.ReadAll(http.MaxBytesReader(w, r.Body, 100000))
+ offer, err := ioutil.ReadAll(http.MaxBytesReader(w, r.Body, readLimit))
if nil != err {
log.Println("Invalid data.")
w.WriteHeader(http.StatusBadRequest)
@@ -213,7 +214,7 @@ func proxyAnswers(ctx *BrokerContext, w
http.ResponseWriter, r *http.Request) {
w.WriteHeader(http.StatusGone)
return
}
- body, err := ioutil.ReadAll(http.MaxBytesReader(w, r.Body, 100000))
+ body, err := ioutil.ReadAll(http.MaxBytesReader(w, r.Body, readLimit))
if nil != err || nil == body || len(body) <= 0 {
log.Println("Invalid data.")
w.WriteHeader(http.StatusBadRequest)
diff --git a/client/lib/rendezvous.go b/client/lib/rendezvous.go
index e53c51e..7f03d13 100644
--- a/client/lib/rendezvous.go
+++ b/client/lib/rendezvous.go
@@ -11,6 +11,7 @@ package lib
import (
"bytes"
"errors"
+ "io"
"io/ioutil"
"log"
"net/http"
@@ -23,6 +24,7 @@ const (
BrokerError503 string = "No snowflake proxies currently
available."
BrokerError400 string = "You sent an invalid offer in the
request."
BrokerErrorUnexpected string = "Unexpected error, no answer."
+ readLimit = 100000 //Maximum number of bytes to be
read from an HTTP response
)
// Signalling Channel to the Broker.
@@ -64,6 +66,23 @@ func NewBrokerChannel(broker string, front string, transport
http.RoundTripper)
return bc
}
+func limitedRead(r io.Reader, limit int64) ([]byte, error) {
+ p, err := ioutil.ReadAll(&io.LimitedReader{r, limit})
+ if err != nil {
+ return p, err
+ }
+
+ //Check to see if limit was exceeded
+ var tmp [1]byte
+ _, err = io.ReadFull(r, tmp[:])
+ if err == io.EOF {
+ err = nil
+ } else if err == nil {
+ err = io.ErrUnexpectedEOF
+ }
+ return p, err
+}
+
// Roundtrip HTTP POST using WebRTC SessionDescriptions.
//
// Send an SDP offer to the broker, which assigns a proxy and responds
@@ -91,7 +110,7 @@ func (bc *BrokerChannel) Negotiate(offer
*webrtc.SessionDescription) (
switch resp.StatusCode {
case http.StatusOK:
- body, err := ioutil.ReadAll(http.MaxBytesReader(nil, resp.Body,
100000))
+ body, err := limitedRead(resp.Body, readLimit)
if nil != err {
return nil, err
}
diff --git a/proxy-go/snowflake.go b/proxy-go/snowflake.go
index ebab790..ececda3 100644
--- a/proxy-go/snowflake.go
+++ b/proxy-go/snowflake.go
@@ -32,6 +32,8 @@ const pollInterval = 5 * time.Second
//client is not going to connect
const dataChannelTimeout = 20 * time.Second
+const readLimit = 100000 //Maximum number of bytes to be read from an HTTP
request
+
var brokerURL *url.URL
var relayURL string
@@ -137,6 +139,23 @@ func genSessionID() string {
return strings.TrimRight(base64.StdEncoding.EncodeToString(buf), "=")
}
+func limitedRead(r io.Reader, limit int64) ([]byte, error) {
+ p, err := ioutil.ReadAll(&io.LimitedReader{r, limit})
+ if err != nil {
+ return p, err
+ }
+
+ //Check to see if limit was exceeded
+ var tmp [1]byte
+ _, err = io.ReadFull(r, tmp[:])
+ if err == io.EOF {
+ err = nil
+ } else if err == nil {
+ err = io.ErrUnexpectedEOF
+ }
+ return p, err
+}
+
func pollOffer(sid string) *webrtc.SessionDescription {
broker := brokerURL.ResolveReference(&url.URL{Path: "proxy"})
timeOfNextPoll := time.Now()
@@ -162,7 +181,7 @@ func pollOffer(sid string) *webrtc.SessionDescription {
if resp.StatusCode != http.StatusOK {
log.Printf("broker returns: %d",
resp.StatusCode)
} else {
- body, err :=
ioutil.ReadAll(http.MaxBytesReader(nil, resp.Body, 100000))
+ body, err := limitedRead(resp.Body, readLimit)
if err != nil {
log.Printf("error reading broker
response: %s", err)
} else {
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