view auto/feature @ 8044:457afc332c67

Stream: don't flush empty buffers created for read errors. When we generate the last_buf buffer for an UDP upstream recv error, it does not contain any data from the wire. ngx_stream_write_filter attempts to forward it anyways, which is incorrect (e.g., UDP upstream ECONNREFUSED will be translated to an empty packet). This happens because we mark the buffer as both 'flush' and 'last_buf', and ngx_stream_write_filter has special handling for flush with certain types of connections (see d127837c714f, 32b0ba4855a6). The flags are meant to be mutually exclusive, so the fix is to ensure that flush and last_buf are not set at the same time. Reproduction: stream { upstream unreachable { server 127.0.0.1:8880; } server { listen 127.0.0.1:8998 udp; proxy_pass unreachable; } } 1 0.000000000 127.0.0.1 → 127.0.0.1 UDP 47 45588 → 8998 Len=5 2 0.000166300 127.0.0.1 → 127.0.0.1 UDP 47 51149 → 8880 Len=5 3 0.000172600 127.0.0.1 → 127.0.0.1 ICMP 75 Destination unreachable (Port unreachable) 4 0.000202400 127.0.0.1 → 127.0.0.1 UDP 42 8998 → 45588 Len=0 Fixes d127837c714f.
author Aleksei Bavshin <a.bavshin@f5.com>
date Mon, 23 May 2022 11:29:44 -0700
parents e3faa5fb7772
children
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# Copyright (C) Igor Sysoev
# Copyright (C) Nginx, Inc.


echo $ngx_n "checking for $ngx_feature ...$ngx_c"

cat << END >> $NGX_AUTOCONF_ERR

----------------------------------------
checking for $ngx_feature

END

ngx_found=no

if test -n "$ngx_feature_name"; then
    ngx_have_feature=`echo $ngx_feature_name \
                   | tr abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ`
fi

if test -n "$ngx_feature_path"; then
    for ngx_temp in $ngx_feature_path; do
        ngx_feature_inc_path="$ngx_feature_inc_path -I $ngx_temp"
    done
fi

cat << END > $NGX_AUTOTEST.c

#include <sys/types.h>
$NGX_INCLUDE_UNISTD_H
$ngx_feature_incs

int main(void) {
    $ngx_feature_test;
    return 0;
}

END


ngx_test="$CC $CC_TEST_FLAGS $CC_AUX_FLAGS $ngx_feature_inc_path \
          -o $NGX_AUTOTEST $NGX_AUTOTEST.c $NGX_TEST_LD_OPT $ngx_feature_libs"

ngx_feature_inc_path=

eval "/bin/sh -c \"$ngx_test\" >> $NGX_AUTOCONF_ERR 2>&1"


if [ -x $NGX_AUTOTEST ]; then

    case "$ngx_feature_run" in

        yes)
            # /bin/sh is used to intercept "Killed" or "Abort trap" messages
            if /bin/sh -c $NGX_AUTOTEST >> $NGX_AUTOCONF_ERR 2>&1; then
                echo " found"
                ngx_found=yes

                if test -n "$ngx_feature_name"; then
                    have=$ngx_have_feature . auto/have
                fi

            else
                echo " found but is not working"
            fi
        ;;

        value)
            # /bin/sh is used to intercept "Killed" or "Abort trap" messages
            if /bin/sh -c $NGX_AUTOTEST >> $NGX_AUTOCONF_ERR 2>&1; then
                echo " found"
                ngx_found=yes

                cat << END >> $NGX_AUTO_CONFIG_H

#ifndef $ngx_feature_name
#define $ngx_feature_name  `$NGX_AUTOTEST`
#endif

END
            else
                echo " found but is not working"
            fi
        ;;

        bug)
            # /bin/sh is used to intercept "Killed" or "Abort trap" messages
            if /bin/sh -c $NGX_AUTOTEST >> $NGX_AUTOCONF_ERR 2>&1; then
                echo " not found"

            else
                echo " found"
                ngx_found=yes

                if test -n "$ngx_feature_name"; then
                    have=$ngx_have_feature . auto/have
                fi
            fi
        ;;

        *)
            echo " found"
            ngx_found=yes

            if test -n "$ngx_feature_name"; then
                have=$ngx_have_feature . auto/have
            fi
        ;;

    esac

else
    echo " not found"

    echo "----------"    >> $NGX_AUTOCONF_ERR
    cat $NGX_AUTOTEST.c  >> $NGX_AUTOCONF_ERR
    echo "----------"    >> $NGX_AUTOCONF_ERR
    echo $ngx_test       >> $NGX_AUTOCONF_ERR
    echo "----------"    >> $NGX_AUTOCONF_ERR
fi

rm -rf $NGX_AUTOTEST*