Tweak test cases to work with or disable accept_filter

The test cases disabling the accept_filter parameter are those involving
GET requests with a body that are meant to be cached, and one test case
covering OOB data. The rest uses the POST method since the httpready
filter will only let syntactically correct GET or HEAD methods pass to
the application.

Apparently FreeBSD's httpready filter considers that a GET request with
a body is syntactically incorrect although this is not specifically said
in the manual. The HTTP specification doesn't forbid such requests and
they are hard to justify considering the semantics of GET and HEAD, but
there are products in the wild relying on that.

On the other hand GET\r\n\r\n isn't considered malformed, see r01881.vtc.

We don't need the dataready filter on FreeBSD for listen addresses that
expect a PROXY protocol header, the httpready filter will effectively
work like that if the request doesn't look like a GET or a HEAD.

bin/varnishtest/tests/b00037.vtc

 varnishtest "Error on multiple Host headers"
 
-server s1 {
-	rxreq
-	txresp
-} -start
-
-varnish v1 -vcl+backend {
-} -start
+varnish v1 -vcl {backend be none;} -start
 
 client c1 {
 	txreq -hdr "Host: foo" -hdr "Host: bar"
@@ -17,7 +11,7 @@ client c1 {
 varnish v1 -expect client_req_400 == 1
 
 client c1 {
-	txreq -hdr "Content-Length: 12" -bodylen 12
+	txreq -method POST -hdr "Content-Length: 12" -bodylen 12
 	rxresp
 	expect resp.status == 400
 } -run

bin/varnishtest/tests/b00046.vtc

@@ -12,6 +12,7 @@ server s1 {
 	send_urgent " "
 } -start
 
+varnish v1 -cliok "param.set accept_filter off"
 varnish v1 -vcl+backend {} -start
 
 client c1 {

bin/varnishtest/tests/b00069.vtc

@@ -2,20 +2,20 @@ varnishtest "HTTP/1 parsing checks"
 
 # Some tricky requests that have been known to cause parsing errors in the past.
 
-server s1 {
+server s1 -repeat 3 {
 	rxreq
 	txresp
 } -start
 
-varnish v1 -vcl+backend {
-} -start
+varnish v1 -vcl+backend "" -start
 
 # This test checks a bug that was dependent on the contents of the buffer left behind
 # by the previous request
 client c1 {
-	send "GET / HTTP/1.1\r\nHost: asdf.com\r\nFoo: baar\r\n\r\n\r\n\r\n\r\n"
+	send "POST / HTTP/1.1\r\nHost: asdf.com\r\nFoo: baar\r\n\r\n\r\n\r\n\r\n"
 	rxresp
-	send "GET / HTTP/1.1\r\nHost: asdf.com\r\nAsdf: b\n \r\n\r\nSj\r"
+	expect resp.status == 200
+	send "POST / HTTP/1.1\r\nHost: asdf.com\r\nAsdf: b\n \r\n\r\nSj\r"
 	rxresp
 	expect resp.status == 200
 } -run
@@ -23,7 +23,7 @@ client c1 {
 # This tests that the line continuation handling doesn't clear out the end of headers
 # [CR]LF
 client c1 {
-	send "GET / HTTP/1.1\r\nHost: asdf.com\r\nAsdf: b\n \r\n\r\nSj"
+	send "POST / HTTP/1.1\r\nHost: asdf.com\r\nAsdf: b\n \r\n\r\nSj"
 	rxresp
 	expect resp.status == 200
 } -run

bin/varnishtest/tests/l00002.vtc

@@ -23,11 +23,11 @@ varnish v1 -vcl+backend {
 } -start
 
 # Request (1001):
-# GET /1 HTTP/1.1\r\n		 17 bytes
+# POST /1 HTTP/1.1\r\n		 18 bytes
 # Host: foo\r\n			 11 bytes
 # Content-Length: 4\r\n		 19 bytes
 # \r\n				  2 bytes
-# Total:			 49 bytes
+# Total:			 50 bytes
 # Response:
 # HTTP/1.1 200 OK\r\n		 17 bytes
 # Content-Length: 1000\r\n	 22 bytes
@@ -72,7 +72,7 @@ varnish v1 -vcl+backend {
 # Total:			 28 bytes
 logexpect l1 -v v1 -g session {
 	expect * 1001	Begin	"^req .* rxreq"
-	expect * =	ReqAcct	"^49 4 53 87 1000 1087$"
+	expect * =	ReqAcct	"^50 4 54 87 1000 1087$"
 	expect 0 =	End
 	expect * 1003	Begin	"^req .* rxreq"
 	expect * =	ReqAcct "^30 0 30 87 2000 2087$"
@@ -87,7 +87,7 @@ logexpect l1 -v v1 -g session {
 
 # Request 1001
 client c1 {
-	txreq -url "/1" -hdr "Host: foo" -body "asdf"
+	txreq -method POST -url "/1" -hdr "Host: foo" -body "asdf"
 	rxresp
 	expect resp.status == 200
 
@@ -104,7 +104,7 @@ client c1 {
 
 logexpect l1 -wait
 
-varnish v1 -expect s_req_hdrbytes == 116
+varnish v1 -expect s_req_hdrbytes == 117
 varnish v1 -expect s_req_bodybytes == 4
 varnish v1 -expect s_resp_hdrbytes == 289
 varnish v1 -expect s_resp_bodybytes == 5000

bin/varnishtest/tests/r01881.vtc

@@ -17,7 +17,7 @@ varnish v1 -vcl+backend {
 } -start
 
 client c1 {
-	txreq -body "foobar"
+	txreq -method POST -body "foobar"
 	rxresp
 	expect resp.status == 200
 } -run

bin/varnishtest/tests/r01914.vtc

@@ -13,6 +13,7 @@ varnish v1 \
     -arg "-s default,1MB" \
     -arg "-s default,1MB" \
     -arg "-s Transient=default" \
+    -arg "-p accept_filter=off" \
     -syntax 4.0 \
     -vcl+backend {
 	import std;

bin/varnishtest/tests/r02105.vtc

@@ -9,6 +9,7 @@ server s1 {
 	txresp
 } -start
 
+varnish v1 -cliok "param.set accept_filter off"
 varnish v1 -vcl+backend {
 	sub vcl_backend_response {
 		set beresp.ttl = 0.5s;

bin/varnishtest/tests/r02266.vtc

@@ -16,6 +16,7 @@ server s1 {
 	send "line2\n"
 } -start
 
+varnish v1 -cliok "param.set accept_filter off"
 varnish v1 -vcl+backend {
 	sub vcl_backend_response {
 		set beresp.do_stream = false;

include/tbl/params.h

@@ -49,7 +49,11 @@ PARAM(
 	/* flags */	XYZZY,
 	/* s-text */
 	"Enable kernel accept-filters. This may require a kernel module to "
-	"be loaded to have an effect when enabled.",
+	"be loaded to have an effect when enabled.\n\n"
+	"Enabling accept_filter may prevent some requests to reach Varnish "
+	"in the first place. Malformed requests may go unnoticed and not "
+	"increase the client_req_400 counter. GET or HEAD requests with a "
+	"body may be blocked altogether.",
 	/* l-text */	NULL,
 	/* func */	NULL
 )