From 2adaa53619bbc3ad9732e788f2a674ba99060217 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ond=C5=99ej=20Sur=C3=BD?= <ondrej@isc.org>
Date: Thu, 8 Sep 2022 18:24:57 +0200
Subject: [PATCH] Handle canceled read during sending data over stats channel

An assertion failure would be triggered when the TCP connection
is canceled during sending the data back to the client.

Don't require the state to be `RECV` on non successful read to
gracefully handle canceled TCP connection during the SEND state of the
HTTPD channel.

(cherry picked from commit 6562227cc8a0732002c01cfc045129bf6080b94c)
---
 lib/isc/httpd.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/lib/isc/httpd.c b/lib/isc/httpd.c
index a701fb2a84..134806bea9 100644
--- a/lib/isc/httpd.c
+++ b/lib/isc/httpd.c
@@ -904,13 +904,14 @@ httpd_request(isc_nmhandle_t *handle, isc_result_t eresult,
 
 	httpd = isc_nmhandle_getdata(handle);
 
-	REQUIRE(httpd->state == RECV);
 	REQUIRE(httpd->handle == handle);
 
 	if (eresult != ISC_R_SUCCESS) {
 		goto cleanup_readhandle;
 	}
 
+	REQUIRE(httpd->state == RECV);
+
 	result = process_request(
 		httpd, region == NULL ? &(isc_region_t){ NULL, 0 } : region,
 		&buflen);
@@ -1195,7 +1196,6 @@ httpd_senddone(isc_nmhandle_t *handle, isc_result_t result, void *arg) {
 	isc_httpd_t *httpd = (isc_httpd_t *)arg;
 
 	REQUIRE(VALID_HTTPD(httpd));
-	REQUIRE(httpd->state == SEND);
 	REQUIRE(httpd->handle == handle);
 
 	isc_buffer_free(&httpd->sendbuffer);
@@ -1222,6 +1222,8 @@ httpd_senddone(isc_nmhandle_t *handle, isc_result_t result, void *arg) {
 		goto cleanup_readhandle;
 	}
 
+	REQUIRE(httpd->state == SEND);
+
 	httpd->state = RECV;
 	httpd->sendhandle = NULL;