Re: [Qemu-devel] [PATCH v2 5/6] io: Ignore websocket PING and PONG frames

[Daniel P. Berrange]

On Mon, Sep 11, 2017 at 09:38:46AM +0100, Daniel P. Berrange wrote:
> On Fri, Sep 08, 2017 at 10:38:00AM -0700, Brandon Carpenter wrote:
> > Keep pings and gratuitous pongs generated by web browsers from killing
> > websocket connections.
> > 
> > Signed-off-by: Brandon Carpenter <address@hidden>
> > ---
> >  io/channel-websock.c | 21 +++++++++++++++++----
> >  1 file changed, 17 insertions(+), 4 deletions(-)
> > 
> > diff --git a/io/channel-websock.c b/io/channel-websock.c
> > index 3183aeff77..50387050d5 100644
> > --- a/io/channel-websock.c
> > +++ b/io/channel-websock.c
> > @@ -86,6 +86,7 @@
> >  #define QIO_CHANNEL_WEBSOCK_HEADER_FIELD_OPCODE 0x0f
> >  #define QIO_CHANNEL_WEBSOCK_HEADER_FIELD_HAS_MASK 0x80
> >  #define QIO_CHANNEL_WEBSOCK_HEADER_FIELD_PAYLOAD_LEN 0x7f
> > +#define QIO_CHANNEL_WEBSOCK_CONTROL_OPCODE_MASK 0x8
> >  
> >  typedef struct QIOChannelWebsockHeader QIOChannelWebsockHeader;
> >  
> > @@ -565,8 +566,11 @@ static int 
> > qio_channel_websock_decode_header(QIOChannelWebsock *ioc,
> >              return -1;
> >          }
> >      } else {
> > -        if (opcode != QIO_CHANNEL_WEBSOCK_OPCODE_BINARY_FRAME) {
> > -            error_setg(errp, "only binary websocket frames are supported");
> > +        if (opcode != QIO_CHANNEL_WEBSOCK_OPCODE_BINARY_FRAME &&
> > +                opcode != QIO_CHANNEL_WEBSOCK_OPCODE_PING &&
> > +                opcode != QIO_CHANNEL_WEBSOCK_OPCODE_PONG) {
> 
> Why would we need to ignore PONG ?  A client should only send a PONG in
> response to a PING that we send, and we never send PINGs.  So if we
> received a PONG that would be a serious error by the client, which should
> cause us to close the connection IMHO>

Never mind, I've just seen that the RFC allows clients to send an
unsolicited PONG


Regards,
Daniel
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