* Add support of XCLIENT to the smtp proxy.

src/proxy.c

@@ -34,14 +34,17 @@ proxy_error_quark (void)
 	return g_quark_from_static_string ("proxy-error");
 }
 
-static void
+void
 rspamd_proxy_close (rspamd_proxy_t *proxy)
 {
-	close (proxy->cfd);
-	close (proxy->bfd);
+	if (!proxy->closed) {
+		close (proxy->cfd);
+		close (proxy->bfd);
 
-	event_del (&proxy->client_ev);
-	event_del (&proxy->backend_ev);
+		event_del (&proxy->client_ev);
+		event_del (&proxy->backend_ev);
+		proxy->closed = TRUE;
+	}
 }
 
 static void
@@ -215,8 +218,8 @@ rspamd_create_proxy (gint cfd, gint bfd, memory_pool_t *pool, struct event_base
 
 	new = memory_pool_alloc0 (pool, sizeof (rspamd_proxy_t));
 
-	new->cfd = cfd;
-	new->bfd = bfd;
+	new->cfd = dup (cfd);
+	new->bfd = dup (bfd);
 	new->pool = pool;
 	new->base = base;
 	new->bufsize = bufsize;

src/proxy.h

@@ -48,6 +48,7 @@ typedef struct rspamd_proxy_s {
 	gint buf_offset;						/**< offset to write */
 	gpointer user_data;						/**< user's data for callbacks */
 	struct timeval *tv;						/**< timeout for communications */
+	gboolean closed;						/**< whether descriptors are closed */
 } rspamd_proxy_t;
 
 /**
@@ -63,4 +64,6 @@ rspamd_proxy_t* rspamd_create_proxy (gint cfd, gint bfd, memory_pool_t *pool,
 		struct event_base *base, gsize bufsize, struct timeval *tv,
 		dispatcher_err_callback_t err_cb, gpointer ud);
 
+void rspamd_proxy_close (rspamd_proxy_t *proxy);
+
 #endif /* PROXY_H_ */

src/smtp_proxy.c

@@ -85,7 +85,10 @@ struct smtp_proxy_ctx {
 enum rspamd_smtp_proxy_state {
 	SMTP_PROXY_STATE_RESOLVE_REVERSE = 0,
 	SMTP_PROXY_STATE_RESOLVE_NORMAL,
-	SMTP_PROXY_STATE_DELAY
+	SMTP_PROXY_STATE_DELAY,
+	SMTP_PROXY_STATE_GREETING,
+	SMTP_PROXY_STATE_XCLIENT,
+	SMTP_PROXY_STATE_PROXY
 };
 
 struct smtp_proxy_session {
@@ -109,10 +112,13 @@ struct smtp_proxy_session {
 	struct smtp_upstream *upstream;
 
 	struct event *delay_timer;
+	struct event upstream_ev;
 
 	gboolean resolved;
 	struct rspamd_dns_resolver *resolver;
 	struct event_base *ev_base;
+
+	GString *upstream_greeting;
 };
 
 #ifndef HAVE_SA_SIGINFO
@@ -180,13 +186,31 @@ static void
 free_smtp_proxy_session (gpointer arg)
 {
 	struct smtp_proxy_session            *session = arg;
+	static const char fatal_smtp_error[] = "521 5.2.1 Internal error" CRLF;
 
 	if (session) {
 		if (session->dispatcher) {
 			rspamd_remove_dispatcher (session->dispatcher);
 		}
 
+		if (session->upstream_greeting) {
+			g_string_free (session->upstream_greeting, TRUE);
+		}
+
+		if (session->state != SMTP_PROXY_STATE_PROXY) {
+			/* Send 521 fatal error */
+			write (session->sock, fatal_smtp_error, sizeof (fatal_smtp_error));
+		}
+
 		close (session->sock);
+
+		if (session->proxy) {
+			rspamd_proxy_close (session->proxy);
+		}
+		if (session->upstream_sock != -1) {
+			event_del (&session->upstream_ev);
+			close (session->upstream_sock);
+		}
 		memory_pool_delete (session->pool);
 		g_slice_free1 (sizeof (struct smtp_proxy_session), session);
 	}
@@ -205,11 +229,193 @@ smtp_proxy_err_proxy (GError * err, void *arg)
 	destroy_session (session->s);
 }
 
+/**
+ * Check whether SMTP greeting is valid
+ * @param s
+ * @return
+ */
+static gint
+check_valid_smtp_greeting (GString *s)
+{
+	gchar								*p;
+
+	p = s->str + s->len - 1;
+	if (s->len < 6 || (*p != '\n' || *(p - 1) != '\r')) {
+		return 1;
+	}
+	p -= 5;
+
+	while (p >= s->str) {
+		/* It is fast to use memcmp here as we compare only 4 bytes */
+		if (memcmp (p, "220 ", 4) == 0) {
+			/* Check position */
+			if (p == s->str || *(p - 1) == '\n') {
+				return 1;
+			}
+			return 0;
+		}
+		else if ((*p == '5' || *p == '4' || *p == '3') &&
+				g_ascii_isdigit (p[1]) && g_ascii_isdigit (p[2]) && p[3] == ' ') {
+			return -1;
+		}
+		p --;
+	}
+
+	return 1;
+}
+
+/*
+ * Handle upstream greeting
+ */
+
+static void
+smtp_proxy_greeting_handler (gint fd, short what, void *arg)
+{
+	struct smtp_proxy_session           *session = arg;
+	gint								 r;
+	gchar								 read_buf[BUFSIZ];
+
+	if (what == EV_READ) {
+		if (session->state == SMTP_PROXY_STATE_GREETING) {
+			/* Fill greeting buffer with new portion of data */
+			r = read (fd, read_buf, sizeof (read_buf) - 1);
+			if (r > 0) {
+				g_string_append_len (session->upstream_greeting, read_buf, r);
+				/* Now search line with 220 */
+				r = check_valid_smtp_greeting (session->upstream_greeting);
+				if (r == 1) {
+					/* Send xclient */
+					if (session->ctx->use_xclient) {
+						r = rspamd_snprintf (read_buf, sizeof (read_buf), "XCLIENT NAME=%s ADDR=%s" CRLF,
+								session->hostname, inet_ntoa (session->client_addr));
+						r = write (session->upstream_sock, read_buf, r);
+
+						if (r < 0 && errno == EAGAIN) {
+							/* Add write event */
+							event_del (&session->upstream_ev);
+							event_set (&session->upstream_ev, session->upstream_sock,
+									EV_WRITE, smtp_proxy_greeting_handler, session);
+							event_base_set (session->ev_base, &session->upstream_ev);
+							event_add (&session->upstream_ev, NULL);
+						}
+						else if (r > 0) {
+							session->upstream_greeting->len = 0;
+							session->state = SMTP_PROXY_STATE_XCLIENT;
+						}
+						else {
+							msg_info ("connection with %s got write error: %s", inet_ntoa (session->client_addr), strerror (errno));
+							destroy_session (session->s);
+						}
+					}
+					else {
+						event_del (&session->upstream_ev);
+						/* Start direct proxy */
+						r = write (session->sock, session->upstream_greeting->str, session->upstream_greeting->len);
+						/* TODO: handle client's error here */
+						if (r > 0) {
+							session->proxy = rspamd_create_proxy (session->sock, session->upstream_sock, session->pool,
+								session->ev_base, session->ctx->proxy_buf_len,
+								&session->ctx->smtp_timeout, smtp_proxy_err_proxy, session);
+							session->state = SMTP_PROXY_STATE_PROXY;
+						}
+						else {
+							msg_info ("connection with %s got write error: %s", inet_ntoa (session->client_addr), strerror (errno));
+							destroy_session (session->s);
+						}
+					}
+				}
+				else if (r == -1) {
+					/* Proxy sent 500 error */
+					msg_info ("connection with %s got smtp error for greeting", session->upstream->name);
+					destroy_session (session->s);
+				}
+			}
+			else {
+				msg_info ("connection with %s got read error: %s", session->upstream->name, strerror (errno));
+				destroy_session (session->s);
+			}
+		}
+		else if (session->state == SMTP_PROXY_STATE_XCLIENT) {
+			/* Fill greeting buffer with new portion of data */
+			r = read (fd, read_buf, sizeof (read_buf) - 1);
+			if (r > 0) {
+				g_string_append_len (session->upstream_greeting, read_buf, r);
+				/* Now search line with 220 */
+				r = check_valid_smtp_greeting (session->upstream_greeting);
+				if (r == 1) {
+					event_del (&session->upstream_ev);
+					/* Start direct proxy */
+					r = write (session->sock, session->upstream_greeting->str, session->upstream_greeting->len);
+					/* TODO: handle client's error here */
+					if (r > 0) {
+						session->proxy = rspamd_create_proxy (session->sock, session->upstream_sock, session->pool,
+								session->ev_base, session->ctx->proxy_buf_len,
+								&session->ctx->smtp_timeout, smtp_proxy_err_proxy, session);
+						session->state = SMTP_PROXY_STATE_PROXY;
+					}
+					else {
+						msg_info ("connection with %s got write error: %s", inet_ntoa (session->client_addr), strerror (errno));
+						destroy_session (session->s);
+					}
+				}
+				else if (r == -1) {
+					/* Proxy sent 500 error */
+					msg_info ("connection with %s got smtp error for xclient", session->upstream->name);
+					destroy_session (session->s);
+				}
+			}
+		}
+		else {
+			msg_info ("connection with %s got read event at improper state: %d", session->upstream->name, session->state);
+			destroy_session (session->s);
+		}
+	}
+	else if (what == EV_WRITE) {
+		if (session->state == SMTP_PROXY_STATE_GREETING) {
+			/* Send xclient again */
+			r = rspamd_snprintf (read_buf, sizeof (read_buf), "XCLIENT NAME=%s ADDR=%s" CRLF,
+					session->hostname, inet_ntoa (session->client_addr));
+			r = write (session->upstream_sock, read_buf, r);
+
+			if (r < 0 && errno == EAGAIN) {
+				/* Add write event */
+				event_del (&session->upstream_ev);
+				event_set (&session->upstream_ev, session->upstream_sock,
+						EV_WRITE, smtp_proxy_greeting_handler, session);
+				event_base_set (session->ev_base, &session->upstream_ev);
+				event_add (&session->upstream_ev, NULL);
+			}
+			else if (r > 0) {
+				session->upstream_greeting->len = 0;
+				session->state = SMTP_PROXY_STATE_XCLIENT;
+				event_del (&session->upstream_ev);
+				event_set (&session->upstream_ev, session->upstream_sock,
+						EV_READ | EV_PERSIST, smtp_proxy_greeting_handler, session);
+				event_base_set (session->ev_base, &session->upstream_ev);
+				event_add (&session->upstream_ev, NULL);
+			}
+			else {
+				msg_info ("connection with %s got write error: %s", session->upstream->name, strerror (errno));
+				destroy_session (session->s);
+			}
+		}
+		else {
+			msg_info ("connection with %s got write event at improper state: %d", session->upstream->name, session->state);
+			destroy_session (session->s);
+		}
+	}
+	else {
+		/* Timeout */
+		msg_info ("connection with %s timed out", session->upstream->name);
+		destroy_session (session->s);
+	}
+}
+
 static gboolean
 create_smtp_proxy_upstream_connection (struct smtp_proxy_session *session)
 {
-	struct smtp_upstream              *selected;
-	struct sockaddr_un                *un;
+	struct smtp_upstream              	*selected;
+	struct sockaddr_un               	*un;
 
 	/* Try to select upstream */
 	selected = (struct smtp_upstream *)get_upstream_round_robin (session->ctx->upstreams,
@@ -237,9 +443,14 @@ create_smtp_proxy_upstream_connection (struct smtp_proxy_session *session)
 	}
 	/* Create a proxy for upstream connection */
 	rspamd_dispatcher_pause (session->dispatcher);
-	session->proxy = rspamd_create_proxy (session->sock, session->upstream_sock, session->pool,
-			session->ev_base, session->ctx->proxy_buf_len,
-			&session->ctx->smtp_timeout, smtp_proxy_err_proxy, session);
+	/* First of all get upstream's greeting */
+	session->state = SMTP_PROXY_STATE_GREETING;
+
+	event_set (&session->upstream_ev, session->upstream_sock, EV_READ | EV_PERSIST, smtp_proxy_greeting_handler, session);
+	event_base_set (session->ev_base, &session->upstream_ev);
+	event_add (&session->upstream_ev, &session->ctx->smtp_timeout);
+
+	session->upstream_greeting = g_string_sized_new (BUFSIZ);
 
 	return TRUE;
 }
@@ -251,7 +462,7 @@ create_smtp_proxy_upstream_connection (struct smtp_proxy_session *session)
 static void
 smtp_delay_handler (gint fd, short what, void *arg)
 {
-	struct smtp_proxy_session *session = arg;
+	struct smtp_proxy_session 				*session = arg;
 
 	remove_normal_event (session->s, (event_finalizer_t) event_del,
 			session->delay_timer);
@@ -275,9 +486,9 @@ smtp_delay_handler (gint fd, short what, void *arg)
 static void
 smtp_make_delay (struct smtp_proxy_session *session)
 {
-	struct event *tev;
-	struct timeval *tv;
-	gint32 jitter;
+	struct event 							*tev;
+	struct timeval 							*tv;
+	gint32 									 jitter;
 
 	if (session->ctx->smtp_delay != 0 && session->state == SMTP_PROXY_STATE_DELAY) {
 		tev = memory_pool_alloc (session->pool, sizeof(struct event));
@@ -308,10 +519,10 @@ smtp_make_delay (struct smtp_proxy_session *session)
 static void
 smtp_dns_cb (struct rspamd_dns_reply *reply, void *arg)
 {
-	struct smtp_proxy_session *session = arg;
-	gint res = 0;
-	union rspamd_reply_element *elt;
-	GList *cur;
+	struct smtp_proxy_session 						*session = arg;
+	gint 											 res = 0;
+	union rspamd_reply_element 						*elt;
+	GList 											*cur;
 
 	switch (session->state)
 	{
@@ -470,6 +681,7 @@ accept_socket (gint fd, short what, void *arg)
 	session->ctx = ctx;
 	session->resolver = ctx->resolver;
 	session->ev_base = ctx->ev_base;
+	session->upstream_sock = -1;
 	worker->srv->stat->connections_count++;
 
 	/* Resolve client's addr */