dma: support relaying to an LMTP endpoint

Approved by:		bapt
Differential Revision:	https://reviews.freebsd.org/D55627
Upstream:		https://github.com/corecode/dma/pull/152

contrib/dma/conf.c

@@ -198,6 +198,8 @@ parse_conf(const char *config_path)
 			config.authpath= data;
 		else if (strcmp(word, "CERTFILE") == 0 && data != NULL)
 			config.certfile = data;
+		else if (strcmp(word, "LMTP") == 0 && data == NULL)
+			config.features |= LMTP;
 		else if (strcmp(word, "MAILNAME") == 0 && data != NULL)
 			config.mailname = data;
 		else if (strcmp(word, "MASQUERADE") == 0 && data != NULL) {
@@ -257,5 +259,10 @@ parse_conf(const char *config_path)
 		/* NOTREACHED */
 	}
 
+	if ((config.features & LMTP) && (config.features & (TLS_OPP | STARTTLS | SECURETRANSFER))) {
+		errlogx(EX_CONFIG, "%s: LMTP does not support TLS", config_path);
+		/* NOTREACHED */
+	}
+
 	fclose(conf);
 }

contrib/dma/dma.conf

@@ -68,3 +68,6 @@
 
 # Directly forward the mail to the SMARTHOST bypassing aliases and local delivery
 #NULLCLIENT
+
+# Use LMTP instead of SMTP for relaying
+#LMTP

contrib/dma/dma.h

@@ -70,6 +70,7 @@
 #define FULLBOUNCE	0x040		/* Bounce the full message */
 #define TLS_OPP		0x080		/* Opportunistic STARTTLS */
 #define NULLCLIENT	0x100		/* Nullclient support */
+#define LMTP		0x400		/* Use LMTP instead of SMTP with the relay */
 
 #ifndef CONF_PATH
 #error Please define CONF_PATH

contrib/dma/net.c

@@ -390,7 +390,7 @@ int perform_server_greeting(int fd, struct smtp_features* features) {
 		Send EHLO
 		XXX allow HELO fallback
 	*/
-	send_remote_command(fd, "EHLO %s", hostname());
+	send_remote_command(fd, "%s %s", config.features & LMTP ? "LHLO" : "EHLO", hostname());
 
 	char buffer[EHLO_RESPONSE_SIZE];
 	memset(buffer, 0, sizeof(buffer));