mtr to a unreachable host is possible again.

In mtr 0.87 it was possible to start mtr against unreachable
host (that local kernel already knew that it is unreachable).
Later it was broken. Make such tracing possible again.

diff --git a/packet/probe.c b/packet/probe.c
index 27bf138eff65fa1c2d5fd63461ab0bd662273039..cf95f8a3f1f3f6d655f60ecd85098ff3fb956e39 100644 (file)
--- a/packet/probe.c
+++ b/packet/probe.c
@@ -356,14 +356,32 @@ int find_source_addr(
         return -1;
     }
 
-    if (connect(sock, (struct sockaddr *) &dest_with_port, len)) {
-        close(sock);
-        return -1;
-    }
+    if (connect(sock, (struct sockaddr *) &dest_with_port, len) == 0) {
+        if (getsockname(sock, (struct sockaddr *) srcaddr, &len)) {
+            close(sock);
+            return -1;
+        }
+    } else {
+#ifdef __linux__
+        /* Linux doesn't require source address, so we can support
+         * a case when mtr is run against unreachable host (that can become
+         * reachable) */
+        if (errno != EHOSTUNREACH) {
+            close(sock);
+            return -1;
+        }
 
-    if (getsockname(sock, (struct sockaddr *) srcaddr, &len)) {
+        if (destaddr->ss_family == AF_INET6) {
+            srcaddr6 = (struct sockaddr_in6 *) srcaddr;
+            srcaddr6->sin6_addr = in6addr_any;
+        } else {
+            srcaddr4 = (struct sockaddr_in *) srcaddr;
+            srcaddr4->sin_addr.s_addr = INADDR_ANY;
+        }
+#else
         close(sock);
         return -1;
+#endif
     }
 
     close(sock);

diff --git a/ui/net.c b/ui/net.c
index 69d44775051772efb34df228a68da5c4da792352..11dd4c8a568dabcd487d722958db8798043b087c 100644 (file)
--- a/ui/net.c
+++ b/ui/net.c
@@ -720,6 +720,16 @@ static void net_find_local_address(
 
     if (connect
         (udp_socket, (struct sockaddr *) &remote_sockaddr, addr_length)) {
+#ifdef __linux__
+        /* Linux doesn't require source address, so we can support
+         * a case when mtr is run against unreachable host (that can become
+         * reachable) */
+        if (errno == EHOSTUNREACH) {
+            close(udp_socket);
+            localaddr[0] = '\0';
+            return;
+        }
+#endif
         error(EXIT_FAILURE, errno, "udp socket connect failed");
     }