submission: client: Add API for adding extra (non-standard) capabilit…

…ies.

src/submission/submission-client.c

@@ -19,6 +19,7 @@
 #include "mail-storage-service.h"
 #include "raw-storage.h"
 #include "imap-urlauth.h"
+#include "smtp-syntax.h"
 #include "smtp-client-connection.h"
 
 #include "submission-backend-relay.h"
@@ -502,6 +503,29 @@ uoff_t client_get_max_mail_size(struct client *client)
 	return max_size;
 }
 
+void client_add_extra_capability(struct client *client, const char *capability,
+				 const char *params)
+{
+	struct client_extra_capability cap;
+
+	/* Don't add capabilties handled by lib-smtp here */
+	i_assert(smtp_capability_find_by_name(capability)
+		 == SMTP_CAPABILITY_NONE);
+
+	/* Avoid committing protocol errors */
+	i_assert(smtp_ehlo_keyword_is_valid(capability));
+	i_assert(params == NULL || smtp_ehlo_params_are_valid(params));
+
+	i_zero(&cap);
+	cap.capability = p_strdup(client->pool, capability);
+	cap.params = p_strdup(client->pool, params);
+
+	if (!array_is_created(&client->extra_capabilities))
+		p_array_init(&client->extra_capabilities, client->pool, 5);
+
+	array_append(&client->extra_capabilities, &cap, 1);
+}
+
 void clients_destroy_all(void)
 {
 	while (submission_clients != NULL) {

src/submission/submission-client.h

@@ -17,6 +17,11 @@ struct client_state {
 	uoff_t data_size;
 };
 
+struct client_extra_capability {
+	const char *capability;
+	const char *params;
+};
+
 struct submission_client_vfuncs {
 	void (*destroy)(struct client *client, const char *prefix,
 			const char *reason);
@@ -79,6 +84,9 @@ struct client {
 	struct submission_backend *backends;
 	unsigned int backends_count;
 
+	/* Extra (non-standard) capabilities */
+	ARRAY(struct client_extra_capability) extra_capabilities;
+
 	/* Module-specific contexts. */
 	ARRAY(union submission_module_context *) module_contexts;
 
@@ -124,6 +132,9 @@ const char *client_state_get_name(struct client *client);
 
 uoff_t client_get_max_mail_size(struct client *client);
 
+void client_add_extra_capability(struct client *client, const char *capability,
+				 const char *params) ATTR_NULL(2);
+
 int client_input_read(struct client *client);
 int client_handle_input(struct client *client);
 

src/submission/submission-commands.c

@@ -20,6 +20,25 @@
  * EHLO, HELO commands
  */
 
+static void
+submission_helo_reply_add_extra(struct client *client,
+				struct smtp_server_reply *reply)
+{
+	const struct client_extra_capability *cap;
+
+	if (!array_is_created(&client->extra_capabilities))
+		return;
+
+	array_foreach(&client->extra_capabilities, cap) {
+		if (cap->params == NULL) {
+			smtp_server_reply_ehlo_add(reply, cap->capability);
+		} else {
+			smtp_server_reply_ehlo_add_param(reply, cap->capability,
+							 "%s", cap->params);
+		}
+	}
+}
+
 void submission_helo_reply_submit(struct smtp_server_cmd_ctx *cmd,
 				  struct smtp_server_cmd_helo *data)
 {
@@ -71,6 +90,8 @@ void submission_helo_reply_submit(struct smtp_server_cmd_ctx *cmd,
 			smtp_server_reply_ehlo_add(reply, "SIZE");
 		}
 		smtp_server_reply_ehlo_add(reply, "VRFY");
+
+		submission_helo_reply_add_extra(client, reply);
 	}
 	smtp_server_reply_submit(reply);
 }