session: Cleanup timeout functions.

It is possible that we get unrelated packets while waiting for
termination, thus waiting indefinitely. As a workaround we have to
check the user-supplied timeout.

include/libssh/misc.h

@@ -78,6 +78,7 @@ const void *_ssh_list_pop_head(struct ssh_list *list);
 #define ssh_list_pop_head(type, ssh_list)\
   ((type)_ssh_list_pop_head(ssh_list))
 
+int ssh_make_milliseconds(long sec, long usec);
 void ssh_timestamp_init(struct ssh_timestamp *ts);
 int ssh_timeout_elapsed(struct ssh_timestamp *ts, int timeout);
 int ssh_timeout_update(struct ssh_timestamp *ts, int timeout);

src/misc.c

@@ -919,6 +919,24 @@ static int ssh_timestamp_difference(struct ssh_timestamp *old,
   return msecs;
 }
 
+/**
+ * @internal
+ * @brief turn seconds and microseconds pair (as provided by user-set options)
+ * into millisecond value
+ * @param[in] sec number of seconds
+ * @param[in] usec number of microseconds
+ * @returns milliseconds, or 10000 if user supplied values are equal to zero
+ */
+int ssh_make_milliseconds(long sec, long usec) {
+	int res = usec ? (usec / 1000) : 0;
+	res += (sec * 1000);
+	if (res == 0) {
+		res = 10 * 1000; /* use a reasonable default value in case
+				* SSH_OPTIONS_TIMEOUT is not set in options. */
+	}
+	return res;
+}
+
 /**
  * @internal
  * @brief Checks if a timeout is elapsed, in function of a previous
@@ -930,17 +948,27 @@ static int ssh_timestamp_difference(struct ssh_timestamp *old,
  *          0 otherwise
  */
 int ssh_timeout_elapsed(struct ssh_timestamp *ts, int timeout) {
-  struct ssh_timestamp now;
-  if(timeout < 0)
-    return 0; // -1 means infinite timeout
-  if(timeout == SSH_TIMEOUT_NONBLOCKING)
-    return 1; // 0 means no timeout
-  ssh_timestamp_init(&now);
+    struct ssh_timestamp now;
 
-  if(ssh_timestamp_difference(ts,&now) >= timeout)
-    return 1;
-  else
-    return 0;
+    switch(timeout) {
+        case -2: /*
+                  * -2 means user-defined timeout as available in
+                  * session->timeout, session->timeout_usec.
+                  */
+            fprintf(stderr, "ssh_timeout_elapsed called with -2. this needs to "
+                            "be fixed. please set a breakpoint on %s:%d and "
+                            "fix the caller\n", __FILE__, __LINE__);
+        case -1: /* -1 means infinite timeout */
+            return 0;
+        case 0: /* 0 means no timeout */
+            return 1;
+        default:
+            break;
+    }
+
+    ssh_timestamp_init(&now);
+
+    return (ssh_timestamp_difference(ts,&now) >= timeout);
 }
 
 /**

src/session.c

@@ -306,7 +306,7 @@ static int ssh_flush_termination(void *c){
  * @brief Blocking flush of the outgoing buffer
  * @param[in] session The SSH session
  * @param[in] timeout Set an upper limit on the time for which this function
- *                    will block, in milliseconds. Specifying a negative value
+ *                    will block, in milliseconds. Specifying -1
  *                    means an infinite timeout. This parameter is passed to
  *                    the poll() function.
  * @returns           SSH_OK on success, SSH_AGAIN if timeout occurred,
@@ -403,17 +403,6 @@ void ssh_set_fd_except(ssh_session session) {
   ssh_socket_set_except(session->socket);
 }
 
-static int ssh_make_milliseconds(long sec, long usec) {
-    int res = usec ? (usec / 1000) : 0;
-    res += (sec * 1000);
-    if (res == 0) {
-        res = 10 * 1000; /* use a reasonable default value in case
-                          * SSH_OPTIONS_TIMEOUT is not set in options. */
-    }
-
-    return res;
-}
-
 /**
  * @internal
  *