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

[Gyan Doshi]

On 2024-06-18 10:00 pm, Timo Rothenpieler wrote:
On 11.06.2024 15:10, Timo Rothenpieler wrote:
On 03.06.2024 22:28, Timo Rothenpieler wrote:
From: BtbN <b...@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.

FWIW, I had to do the same for securetransport on a project a couple of 
years back to get rtmps working. Worked fine, and did not get any 
reports of ill-effects.

Regards,
Gyan

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