From 27964ddaf2463794c46a12fe597533d27639f2f2 Mon Sep 17 00:00:00 2001
From: Andy Green <andy@warmcat.com>
Date: Thu, 8 Oct 2020 14:06:43 +0100
Subject: [PATCH] ws: reporting PONG with pmd enabled

Add a return code NOTHING_WE_SHOULD_DO indicating that the
extension determined by ext-specific means its operation was
disabled on this frame.

https://github.com/warmcat/libwebsockets/issues/2076
---
 lib/core-net/private-lib-core-net.h             |  1 +
 lib/roles/ws/client-parser-ws.c                 |  1 +
 lib/roles/ws/ext/extension-permessage-deflate.c | 14 ++++++++++++--
 lib/roles/ws/ops-ws.c                           |  4 +++-
 4 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/lib/core-net/private-lib-core-net.h b/lib/core-net/private-lib-core-net.h
index cdbc1ba24..044b69803 100644
--- a/lib/core-net/private-lib-core-net.h
+++ b/lib/core-net/private-lib-core-net.h
@@ -174,6 +174,7 @@ enum pmd_return {
 	PMDR_HAS_PENDING,
 	PMDR_EMPTY_NONFINAL,
 	PMDR_EMPTY_FINAL,
+	PMDR_NOTHING_WE_SHOULD_DO,
 
 	PMDR_FAILED = -1
 };
diff --git a/lib/roles/ws/client-parser-ws.c b/lib/roles/ws/client-parser-ws.c
index cacadd298..688e1ebda 100644
--- a/lib/roles/ws/client-parser-ws.c
+++ b/lib/roles/ws/client-parser-ws.c
@@ -554,6 +554,7 @@ drain_extension:
 				return -1;
 			}
 			if (n == PMDR_DID_NOTHING)
+				/* ie, not PMDR_NOTHING_WE_SHOULD_DO */
 				break;
 #endif
 			lwsl_ext("%s: post inflate ebuf in len %d / out len %d\n",
diff --git a/lib/roles/ws/ext/extension-permessage-deflate.c b/lib/roles/ws/ext/extension-permessage-deflate.c
index 58fc7fa7a..de7fc1d41 100644
--- a/lib/roles/ws/ext/extension-permessage-deflate.c
+++ b/lib/roles/ws/ext/extension-permessage-deflate.c
@@ -192,10 +192,20 @@ lws_extension_callback_pm_deflate(struct lws_context *context,
 		lwsl_ext(" %s: LWS_EXT_CB_PAYLOAD_RX: in %d, existing in %d\n",
 			 __func__, pmdrx->eb_in.len, priv->rx.avail_in);
 
-		/* if this frame is not marked as compressed, we ignore it */
+		/*
+		 * If this frame is not marked as compressed,
+		 * there is nothing we should do with it
+		 */
 
 		if (!(wsi->ws->rsv_first_msg & 0x40) || (wsi->ws->opcode & 8))
-			return PMDR_DID_NOTHING;
+			/*
+			 * This is a bit different than DID_NOTHING... we have
+			 * identified using ext-private bits in the packet, or
+			 * by it being a control fragment that we SHOULD not do
+			 * anything to it, parent should continue as if we
+			 * processed it
+			 */
+			return PMDR_NOTHING_WE_SHOULD_DO;
 
 		/*
 		 * we shouldn't come back in here if we already applied the
diff --git a/lib/roles/ws/ops-ws.c b/lib/roles/ws/ops-ws.c
index 71fb1c72f..de6d098b9 100644
--- a/lib/roles/ws/ops-ws.c
+++ b/lib/roles/ws/ops-ws.c
@@ -633,6 +633,7 @@ drain_extension:
 				return -1;
 			}
 			if (n == PMDR_DID_NOTHING)
+				/* ie, not PMDR_NOTHING_WE_SHOULD_DO */
 				break;
 #endif
 			lwsl_debug("%s: post ext ret %d, ebuf in %d / out %d\n",
@@ -693,7 +694,8 @@ utf8_fail:
 
 			if (n == PMDR_DID_NOTHING
 #if !defined(LWS_WITHOUT_EXTENSIONS)
-				       	||
+					||
+			    n == PMDR_NOTHING_WE_SHOULD_DO ||
 			    n == PMDR_UNKNOWN
 #endif
 			    )