From: Joe Orton <jorton@apache.org>
Date: Tue, 23 Jun 2020 08:45:07 +0000 (+0000)
Subject: Add "v6only" Listen option to enable IPV6_V6ONLY in v4mapped builds
X-Git-Tag: 2.5.0-alpha2-ci-test-only~1352
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2f9cba2ad01a6dda48d19da475fea72ca3637104;p=thirdparty%2Fapache%2Fhttpd.git

Add "v6only" Listen option to enable IPV6_V6ONLY in v4mapped builds
where it is otherwise always disabled.

* include/ap_listen.h: Define AP_LISTEN_V6ONLY.

* server/listen.c (make_sock): Set v6only_setting to 1 if
  AP_LISTEN_V6ONLY flag is set for the listener.
  (parse_listen_flags): Parse "v6only" flag.

PR: 54878


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1879106 13f79535-47bb-0310-9956-ffa450edef68
---

diff --git a/CHANGES b/CHANGES
index f24e24c8f2e..0ae7ba816f2 100644
--- a/CHANGES
+++ b/CHANGES
@@ -38,7 +38,7 @@ Changes with Apache 2.5.1
      the connection inside mod_ssl.  [Joe Orton]
  
   *) core: Add optional "options=" argument to Listen.  Supported
-     keywords are "freebind" and "reuseport".  PR 61865.
+     keywords are "freebind", "reuseport" and "v6only".  PR 61865.
      [Jan Kaluza, Lubos Uhliarik <luhliari redhat.com>, Joe Orton]
 
   *) config: Allow for environment variable substitution with default value,
diff --git a/docs/manual/mod/mpm_common.xml b/docs/manual/mod/mpm_common.xml
index be8a2ff5b2f..bd6840c5a85 100644
--- a/docs/manual/mod/mpm_common.xml
+++ b/docs/manual/mod/mpm_common.xml
@@ -270,6 +270,14 @@ Listen 192.170.2.5:8000
       <li><code>reuseport</code>: The <code>SO_REUSEPORT</code> socket
       option is enabled, allowing a Listen directive to bind to a port
       which may already be in use by another process.</li>
+
+      <li><code>v6only</code>: The <code>IPV6_V6ONLY</code> socket
+      option is enabled, allowing a Listen directive to bind to an
+      IPv6 address without also accepting connections via IPv4, or
+      conflicting with a Listen directive using an IPv4 address bound
+      to the same port.  (If the server is built with IPv4-mapped
+      addresses <em>disabled</em>, this is the default behaviour and
+      this option has no effect.)</li>
     </ul>
        
     <note><title>Error condition</title>
diff --git a/include/ap_listen.h b/include/ap_listen.h
index 2329cae70cb..1f151f98a48 100644
--- a/include/ap_listen.h
+++ b/include/ap_listen.h
@@ -42,6 +42,7 @@ typedef apr_status_t (*accept_function)(void **csd, ap_listen_rec *lr, apr_pool_
 #define AP_LISTEN_SPECIFIC_ERRORS (0x0001)
 #define AP_LISTEN_FREEBIND        (0x0002)
 #define AP_LISTEN_REUSEPORT       (0x0004)
+#define AP_LISTEN_V6ONLY          (0x0008)
 
 /**
  * @brief Apache's listeners record.
diff --git a/server/listen.c b/server/listen.c
index 991a3f2c30d..445d1202c93 100644
--- a/server/listen.c
+++ b/server/listen.c
@@ -78,7 +78,7 @@ static apr_status_t make_sock(apr_pool_t *p, ap_listen_rec *server, int do_bind_
     int one = 1;
 #if APR_HAVE_IPV6
 #ifdef AP_ENABLE_V4_MAPPED
-    int v6only_setting = 0;
+    int v6only_setting = (server->flags & AP_LISTEN_V6ONLY) ? 1 : 0;
 #else
     int v6only_setting = 1;
 #endif
@@ -1048,6 +1048,8 @@ static const char *parse_listen_flags(apr_pool_t *temp_pool, const char *arg,
             flags |= AP_LISTEN_FREEBIND;
         else if (ap_cstr_casecmp(token, "reuseport") == 0)
             flags |= AP_LISTEN_REUSEPORT;
+        else if (ap_cstr_casecmp(token, "v6only") == 0)
+            flags |= AP_LISTEN_V6ONLY;
         else
             return apr_psprintf(temp_pool, "Unknown Listen option '%s' in '%s'",
                                 token, arg);