Solved issue #2910 - Added support for IPv6 with fallback to IPv4 for ssh

1 files changed, 59 insertions, 3 deletions

diff --git a/src/remmina_ssh.c b/src/remmina_ssh.c
index a5c9101ce..d5c6f1115 100644
--- a/src/remmina_ssh.c
+++ b/src/remmina_ssh.c
@@ -1672,6 +1672,12 @@ remmina_ssh_init_session(RemminaSSH *ssh)
 	socket_t sshsock;
 	gint optval;
 #endif
+	// Handle IPv4 / IPv6 dual stack
+	char *hostname;
+	struct addrinfo hints,*aitop,*ai;
+	char ipstr[INET6_ADDRSTRLEN];
+	void *addr4=NULL;
+	void *addr6=NULL;
 
 	ssh->callback = g_new0(struct ssh_callbacks_struct, 1);
 
@@ -1840,12 +1846,62 @@ remmina_ssh_init_session(RemminaSSH *ssh)
 	else
 		REMMINA_DEBUG("SSH_OPTIONS_COMPRESSION does not have a valid value. %s", ssh->compression);
 
-	if (ssh_connect(ssh->session)) {
-		// TRANSLATORS: The placeholder %s is an error message
-		remmina_ssh_set_error(ssh, _("Could not start SSH session. %s"));
+	// Handle the dual IPv4 / IPv6 stack
+	// Prioritize IPv6 and fallback to IPv4
+
+	// Run the DNS resolution 
+	// First retrieve host from the ssh->session structure
+	ssh_options_get(ssh->session, SSH_OPTIONS_HOST, &hostname);
+	// Call getaddrinfo
+        memset(&hints, 0, sizeof(hints));
+        hints.ai_family = AF_UNSPEC;
+        hints.ai_socktype = SOCK_STREAM;
+        if ((getaddrinfo(hostname, NULL, &hints, &aitop)) != 0) {
+		ssh->error = g_strdup_printf("Could not resolve hostname %s", hostname);
+		REMMINA_DEBUG(ssh->error);
 		return FALSE;
 	}
 
+	// We have one or more addesses now, extract them
+	ai = aitop;
+	while (ai != NULL) {
+    		if (ai->ai_family == AF_INET) { // IPv4
+			struct sockaddr_in *ipv4 = (struct sockaddr_in *)ai->ai_addr;
+			addr4 = &(ipv4->sin_addr);
+		} else { // IPv6
+			struct sockaddr_in6 *ipv6 = (struct sockaddr_in6 *)ai->ai_addr;
+			addr6 = &(ipv6->sin6_addr);
+		}
+		ai = ai->ai_next;
+	}
+	freeaddrinfo(aitop);
+
+	unsigned short int success6 = 0;
+	if (addr6 != NULL) {
+		// Try IPv6 first
+		inet_ntop(AF_INET6, addr6, ipstr, sizeof ipstr);
+		ssh_options_set(ssh->session, SSH_OPTIONS_HOST, ipstr);
+		REMMINA_DEBUG("Setting SSH_OPTIONS_HOST to IPv6 %s", ipstr);
+		if (ssh_connect(ssh->session)) {
+			ssh_disconnect(ssh->session);
+			REMMINA_DEBUG("IPv6 session failed");
+		} else {
+			success6 = 1;
+			REMMINA_DEBUG("IPv6 session success !");
+		}
+	}
+	if (success6 == 0) {
+		// Fallback to IPv4 
+		inet_ntop(AF_INET, addr4, ipstr, sizeof ipstr);
+		ssh_options_set(ssh->session, SSH_OPTIONS_HOST, ipstr);
+		REMMINA_DEBUG("Setting SSH_OPTIONS_HOST to IPv4 %s", ipstr);
+		if (ssh_connect(ssh->session)) {
+			// TRANSLATORS: The placeholder %s is an error message
+			remmina_ssh_set_error(ssh, _("Could not start SSH session. %s"));
+			return FALSE;
+		}
+	}
+
 #ifdef HAVE_NETINET_TCP_H
 	/* Set keepalive on SSH socket, so we can keep firewalls awaken and detect
 	 * when we loss the tunnel */