write silence on the channel during t.38 negotiation

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@327514 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/res/res_fax.c b/res/res_fax.c
index 5202e6323cfcfcc9e8019425ebaf0af4ccce878e..2b3fec19422742078d7239eb7f0a662b0eb2b957 100644 (file)
--- a/res/res_fax.c
+++ b/res/res_fax.c
@@ -2977,8 +2977,21 @@ static struct ast_frame *fax_gateway_framehook(struct ast_channel *chan, struct
 
        /* force silence on the line if T.38 negotiation might be taking place */
        if (!ast_tvzero(gateway->ced_timeout_start) || (gateway->t38_state != T38_STATE_UNAVAILABLE && gateway->t38_state != T38_STATE_REJECTED)) {
-               /* XXX may need to return a silence frame here */
-               return &ast_null_frame;
+               if (f->frametype == AST_FRAME_VOICE && f->subclass.format.id == AST_FORMAT_SLINEAR) {
+                       short silence_buf[f->samples];
+                       struct ast_frame silence_frame = {
+                               .frametype = AST_FRAME_VOICE,
+                               .data.ptr = silence_buf,
+                               .samples = f->samples,
+                               .datalen = sizeof(silence_buf),
+                       };
+                       ast_format_set(&silence_frame.subclass.format, AST_FORMAT_SLINEAR, 0);
+                       memset(silence_buf, 0, sizeof(silence_buf));
+
+                       return ast_frisolate(&silence_frame);
+               } else {
+                       return &ast_null_frame;
+               }
        }
 
        return f;