[Feature] Allow to discard messages instead of rejection

Issue: #1723

3 files changed, 32 insertions, 13 deletions

diff --git a/src/libserver/milter.c b/src/libserver/milter.c
index dad7c5afa..4f235c2aa 100644
--- a/src/libserver/milter.c
+++ b/src/libserver/milter.c
@@ -49,6 +49,7 @@
 struct rspamd_milter_context {
 	gchar *spam_header;
 	void *sessions_cache;
+	gboolean discard_on_reject;
 };
 
 static struct rspamd_milter_context *milter_ctx = NULL;
@@ -1565,18 +1566,23 @@ rspamd_milter_send_task_results (struct rspamd_milter_session *session,
 
 	switch (action) {
 	case METRIC_ACTION_REJECT:
-		rcode = rspamd_fstring_new_init (RSPAMD_MILTER_RCODE_REJECT,
-				sizeof (RSPAMD_MILTER_RCODE_REJECT) - 1);
-		xcode = rspamd_fstring_new_init (RSPAMD_MILTER_XCODE_REJECT,
-				sizeof (RSPAMD_MILTER_XCODE_REJECT) - 1);
-
-		if (!reply) {
-			reply = rspamd_fstring_new_init (RSPAMD_MILTER_REJECT_MESSAGE,
-					sizeof (RSPAMD_MILTER_REJECT_MESSAGE) - 1);
+		if (milter_ctx->discard_on_reject) {
+			rspamd_milter_send_action (session, RSPAMD_MILTER_DISCARD);
 		}
+		else {
+			rcode = rspamd_fstring_new_init (RSPAMD_MILTER_RCODE_REJECT,
+					sizeof (RSPAMD_MILTER_RCODE_REJECT) - 1);
+			xcode = rspamd_fstring_new_init (RSPAMD_MILTER_XCODE_REJECT,
+					sizeof (RSPAMD_MILTER_XCODE_REJECT) - 1);
+
+			if (!reply) {
+				reply = rspamd_fstring_new_init (RSPAMD_MILTER_REJECT_MESSAGE,
+						sizeof (RSPAMD_MILTER_REJECT_MESSAGE) - 1);
+			}
 
-		rspamd_milter_set_reply (session, rcode, xcode, reply);
-		rspamd_milter_send_action (session, RSPAMD_MILTER_REJECT);
+			rspamd_milter_set_reply (session, rcode, xcode, reply);
+			rspamd_milter_send_action (session, RSPAMD_MILTER_REJECT);
+		}
 		break;
 	case METRIC_ACTION_SOFT_REJECT:
 		rcode = rspamd_fstring_new_init (RSPAMD_MILTER_RCODE_TEMPFAIL,
@@ -1638,7 +1644,8 @@ cleanup:
 }
 
 void
-rspamd_milter_init_library (const gchar *spam_header, void *sessions_cache)
+rspamd_milter_init_library (const gchar *spam_header, void *sessions_cache,
+		gboolean discard_on_reject)
 {
 	if (milter_ctx) {
 		g_free (milter_ctx->spam_header);
@@ -1655,6 +1662,7 @@ rspamd_milter_init_library (const gchar *spam_header, void *sessions_cache)
 	}
 
 	milter_ctx->sessions_cache = sessions_cache;
+	milter_ctx->discard_on_reject = discard_on_reject;
 }
 
 rspamd_mempool_t *
diff --git a/src/libserver/milter.h b/src/libserver/milter.h
index 8550ecc97..2a07cef99 100644
--- a/src/libserver/milter.h
+++ b/src/libserver/milter.h
@@ -149,7 +149,7 @@ void rspamd_milter_send_task_results (struct rspamd_milter_session *session,
  * @param spam_header spam header name (must NOT be NULL)
  */
 void rspamd_milter_init_library (const gchar *spam_header,
-		void *sessions_cache);
+		void *sessions_cache, gboolean discard_on_reject);
 
 /**
  * Returns pool for a session
diff --git a/src/rspamd_proxy.c b/src/rspamd_proxy.c
index 4228ebef0..efb7e957b 100644
--- a/src/rspamd_proxy.c
+++ b/src/rspamd_proxy.c
@@ -131,6 +131,8 @@ struct rspamd_proxy_ctx {
 	gboolean has_self_scan;
 	/* It is not HTTP but milter proxy */
 	gboolean milter;
+	/* Discard messages instead of rejecting them */
+	gboolean discard_on_reject;
 	/* Milter spam header */
 	gchar *spam_header;
 	/* Sessions cache */
@@ -791,6 +793,14 @@ init_rspamd_proxy (struct rspamd_config *cfg)
 			"Accept milter connections, not HTTP");
 	rspamd_rcl_register_worker_option (cfg,
 			type,
+			"discard_on_reject",
+			rspamd_rcl_parse_struct_boolean,
+			ctx,
+			G_STRUCT_OFFSET (struct rspamd_proxy_ctx, discard_on_reject),
+			0,
+			"Tell MTA to discard rejected messages silently");
+	rspamd_rcl_register_worker_option (cfg,
+			type,
 			"spam_header",
 			rspamd_rcl_parse_struct_string,
 			ctx,
@@ -2063,7 +2073,8 @@ start_rspamd_proxy (struct rspamd_worker *worker) {
 				ctx->ev_base);
 	}
 
-	rspamd_milter_init_library (ctx->spam_header, ctx->sessions_cache);
+	rspamd_milter_init_library (ctx->spam_header, ctx->sessions_cache,
+			ctx->discard_on_reject);
 
 	event_base_loop (ctx->ev_base, 0);
 	rspamd_worker_block_signals ();