upstream: De-magic the x11 base port number into a define. ok djm@

OpenBSD-Commit-ID: 23b85ca9d222cb739b9c33ee5e4d6ac9fdeecbfa

channels.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: channels.c,v 1.441 2024/12/05 06:47:00 dtucker Exp $ */
+/* $OpenBSD: channels.c,v 1.442 2024/12/05 06:49:26 dtucker Exp $ */
 /*
  * Author: Tatu Ylonen <[email protected]>
  * Copyright (c) 1995 Tatu Ylonen <[email protected]>, Espoo, Finland
@@ -94,6 +94,8 @@
 #define	NUM_SOCKS	10
 
 /* -- X11 forwarding */
+/* X11 port for display :0 */
+#define X11_BASE_PORT	6000
 /* Maximum number of fake X11 displays to try. */
 #define MAX_DISPLAYS  1000
 
@@ -5004,13 +5006,13 @@ x11_create_display_inet(struct ssh *ssh, int x11_display_offset,
 	int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
 
 	if (chanids == NULL || x11_display_offset < 0 ||
-	    x11_display_offset > UINT16_MAX - 6000 - MAX_DISPLAYS)
+	    x11_display_offset > UINT16_MAX - X11_BASE_PORT - MAX_DISPLAYS)
 		return -1;
 
 	for (display_number = x11_display_offset;
 	    display_number < MAX_DISPLAYS;
 	    display_number++) {
-		port = 6000 + display_number;
+		port = X11_BASE_PORT + display_number;
 		memset(&hints, 0, sizeof(hints));
 		hints.ai_family = ssh->chanctxt->IPv4or6;
 		hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
@@ -5227,7 +5229,7 @@ x11_connect_display(struct ssh *ssh)
 	 * display number.
 	 */
 	if (sscanf(cp + 1, "%u", &display_number) != 1 ||
-	    display_number > UINT16_MAX - 6000) {
+	    display_number > UINT16_MAX - X11_BASE_PORT) {
 		error("Could not parse display number from DISPLAY: %.100s",
 		    display);
 		return -1;
@@ -5237,7 +5239,7 @@ x11_connect_display(struct ssh *ssh)
 	memset(&hints, 0, sizeof(hints));
 	hints.ai_family = ssh->chanctxt->IPv4or6;
 	hints.ai_socktype = SOCK_STREAM;
-	snprintf(strport, sizeof strport, "%u", 6000 + display_number);
+	snprintf(strport, sizeof strport, "%u", X11_BASE_PORT + display_number);
 	if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
 		error("%.100s: unknown host. (%s)", buf,
 		ssh_gai_strerror(gaierr));
@@ -5253,7 +5255,7 @@ x11_connect_display(struct ssh *ssh)
 		/* Connect it to the display. */
 		if (connect(sock, ai->ai_addr, ai->ai_addrlen) == -1) {
 			debug2("connect %.100s port %u: %.100s", buf,
-			    6000 + display_number, strerror(errno));
+			    X11_BASE_PORT + display_number, strerror(errno));
 			close(sock);
 			continue;
 		}
@@ -5263,7 +5265,7 @@ x11_connect_display(struct ssh *ssh)
 	freeaddrinfo(aitop);
 	if (!ai) {
 		error("connect %.100s port %u: %.100s", buf,
-		    6000 + display_number, strerror(errno));
+		    X11_BASE_PORT + display_number, strerror(errno));
 		return -1;
 	}
 	set_nodelay(sock);