[FFmpeg-devel] [PATCH] avformat/tls_schannel: forward AVIO_FLAG_NONBLOCK to tcp stream

[Timo Rothenpieler]

On 03.06.2024 22:28, Timo Rothenpieler wrote:
> From: BtbN <btbn at btbn.de>

This is fixed locally

> Fixes for example rtmps streaming over schannel.
> ---
>   libavformat/tls_schannel.c | 15 ++++++++++++++-
>   1 file changed, 14 insertions(+), 1 deletion(-)
> 
> diff --git a/libavformat/tls_schannel.c b/libavformat/tls_schannel.c
> index 214a47a218..7265a9794d 100644
> --- a/libavformat/tls_schannel.c
> +++ b/libavformat/tls_schannel.c
> @@ -113,6 +113,7 @@ static int tls_shutdown_client(URLContext *h)
>                                                c->request_flags, 0, 0, NULL, 0, &c->ctxt_handle,
>                                                &outbuf_desc, &c->context_flags, &c->ctxt_timestamp);
>           if (sspi_ret == SEC_E_OK || sspi_ret == SEC_I_CONTEXT_EXPIRED) {
> +            s->tcp->flags &= ~AVIO_FLAG_NONBLOCK;
>               ret = ffurl_write(s->tcp, outbuf.pvBuffer, outbuf.cbBuffer);
>               FreeContextBuffer(outbuf.pvBuffer);
>               if (ret < 0 || ret != outbuf.cbBuffer)
> @@ -316,6 +317,7 @@ static int tls_client_handshake(URLContext *h)
>           goto fail;
>       }
>   
> +    s->tcp->flags &= ~AVIO_FLAG_NONBLOCK;
>       ret = ffurl_write(s->tcp, outbuf.pvBuffer, outbuf.cbBuffer);
>       FreeContextBuffer(outbuf.pvBuffer);
>       if (ret < 0 || ret != outbuf.cbBuffer) {
> @@ -416,11 +418,16 @@ static int tls_read(URLContext *h, uint8_t *buf, int len)
>               }
>           }
>   
> +        s->tcp->flags &= ~AVIO_FLAG_NONBLOCK;
> +        s->tcp->flags |= h->flags & AVIO_FLAG_NONBLOCK;
> +
>           ret = ffurl_read(s->tcp, c->enc_buf + c->enc_buf_offset,
>                            c->enc_buf_size - c->enc_buf_offset);
>           if (ret == AVERROR_EOF) {
>               c->connection_closed = 1;
>               ret = 0;
> +        } else if (ret == AVERROR(EAGAIN)) {
> +            ret = 0;
>           } else if (ret < 0) {
>               av_log(h, AV_LOG_ERROR, "Unable to read from socket\n");
>               return ret;
> @@ -564,8 +571,14 @@ static int tls_write(URLContext *h, const uint8_t *buf, int len)
>       sspi_ret = EncryptMessage(&c->ctxt_handle, 0, &outbuf_desc, 0);
>       if (sspi_ret == SEC_E_OK)  {
>           len = outbuf[0].cbBuffer + outbuf[1].cbBuffer + outbuf[2].cbBuffer;
> +
> +        s->tcp->flags &= ~AVIO_FLAG_NONBLOCK;
> +        s->tcp->flags |= h->flags & AVIO_FLAG_NONBLOCK;
> +
>           ret = ffurl_write(s->tcp, data, len);
> -        if (ret < 0 || ret != len) {
> +        if (ret == AVERROR(EAGAIN)) {
> +            goto done;
> +        } else if (ret < 0 || ret != len) {
>               ret = AVERROR(EIO);
>               av_log(h, AV_LOG_ERROR, "Writing encrypted data to socket failed\n");
>               goto done;

ping


I'm specifically unsure if implementing the sending-side like this is 
valid and would appreciate review from someone familiar with the code 
and schannel.