Fix a bug where you might flush some data on a tls connection, and then

add some more data to be flushed but never turn POLLOUT on. not sure
how commonly this bug was hit, but it would be a doozy.

Also add some asserts to see if it happens elsewhere.


svn:r1142

3 files changed, 16 insertions, 4 deletions

diff --git a/src/or/connection.c b/src/or/connection.c
index 4d7933696..1e9876f8c 100644
--- a/src/or/connection.c
+++ b/src/or/connection.c
@@ -506,7 +506,7 @@ int connection_handle_write(connection_t *conn) {
   } else {
     if(flush_buf(conn->s, conn->outbuf, &conn->outbuf_flushlen) < 0)
       return -1;
-      /* conns in CONNECTING state will fall through... */
+    /* conns in CONNECTING state will fall through... */
   }
 
   if(!connection_wants_to_flush(conn)) /* it's done flushing */
@@ -527,9 +527,8 @@ void connection_write_to_buf(const char *string, int len, connection_t *conn) {
     return;
   }
 
-  /* XXX if linkpadding, this only applies to conns that aren't open OR connections */
   connection_start_writing(conn);
-#define MIN_TLS_FLUSHLEN 16300
+#define MIN_TLS_FLUSHLEN 15872
 /* openssl tls record size is 16383, this is close. The goal here is to
  * push data out as soon as we know there's enough for a tls record, so
  * during periods of high load we won't read the entire megabyte from
@@ -544,7 +543,11 @@ void connection_write_to_buf(const char *string, int len, connection_t *conn) {
       log_fn(LOG_WARN,"flushing failed.");
     }
   }
-  conn->outbuf_flushlen += len;
+  if(len > 0) { /* if there's any left over */
+    conn->outbuf_flushlen += len;
+    connection_start_writing(conn);
+    /* because connection_handle_write() above might have stopped writing */
+  }
 }
 
 connection_t *connection_exact_get_by_addr_port(uint32_t addr, uint16_t port) {
@@ -758,6 +761,10 @@ void assert_connection_ok(connection_t *conn, time_t now)
   assert(conn->type >= _CONN_TYPE_MIN);
   assert(conn->type <= _CONN_TYPE_MAX);
 
+  if(conn->outbuf_flushlen > 0) {
+    assert(connection_is_writing(conn) || conn->wants_to_write);
+  }
+
   /* XXX check: wants_to_read, wants_to_write, s, poll_index,
    * marked_for_close. */
 
diff --git a/src/or/main.c b/src/or/main.c
index 9abb8aef2..7a394fd5a 100644
--- a/src/or/main.c
+++ b/src/or/main.c
@@ -136,6 +136,10 @@ void connection_start_reading(connection_t *conn) {
   poll_array[conn->poll_index].events |= POLLIN;
 }
 
+int connection_is_writing(connection_t *conn) {
+  return poll_array[conn->poll_index].events & POLLOUT;
+}
+
 void connection_stop_writing(connection_t *conn) {
 
   assert(conn && conn->poll_index < nfds);
diff --git a/src/or/or.h b/src/or/or.h
index 3aff94637..d7cd00cdb 100644
--- a/src/or/or.h
+++ b/src/or/or.h
@@ -748,6 +748,7 @@ void connection_watch_events(connection_t *conn, short events);
 int connection_is_reading(connection_t *conn);
 void connection_stop_reading(connection_t *conn);
 void connection_start_reading(connection_t *conn);
+int connection_is_writing(connection_t *conn);
 void connection_stop_writing(connection_t *conn);
 void connection_start_writing(connection_t *conn);