Changeset 7142:b9d919b53593 in nginx


Ignore:
Timestamp:
09/11/17 12:32:31 (3 years ago)
Author:
Roman Arutyunyan <arut@…>
Branch:
stable-1.12
Phase:
public
Graft:
7098:7bfbf73db920
Message:

Stream: relaxed next upstream condition (ticket #1317).

When switching to a next upstream, some buffers could be stuck in the middle
of the filter chain. A condition existed that raised an error when this
happened. As it turned out, this condition prevented switching to a next
upstream if ssl preread was used with the TCP protocol (see the ticket).

In fact, the condition does not make sense for TCP, since after successful
connection to an upstream switching to another upstream never happens. As for
UDP, the issue with stuck buffers is unlikely to happen, but is still possible.
Specifically, if a filter delays sending data to upstream.

The condition can be relaxed to only check the "buffered" bitmask of the
upstream connection. The new condition is simpler and fixes the ticket issue
as well. Additionally, the upstream_out chain is now reset for UDP prior to
connecting to a new upstream to prevent repeating the client data twice.

File:
1 edited

Legend:

Unmodified
Added
Removed
  • src/stream/ngx_stream_proxy_module.c

    r6868 r7142  
    16781678    pc = u->peer.connection;
    16791679
    1680     if (u->upstream_out || u->upstream_busy || (pc && pc->buffered)) {
     1680    if (pc && pc->buffered) {
    16811681        ngx_log_error(NGX_LOG_ERR, s->connection->log, 0,
    1682                       "pending buffers on next upstream");
     1682                      "buffered data on next upstream");
    16831683        ngx_stream_proxy_finalize(s, NGX_STREAM_INTERNAL_SERVER_ERROR);
    16841684        return;
     1685    }
     1686
     1687    if (s->connection->type == SOCK_DGRAM) {
     1688        u->upstream_out = NULL;
    16851689    }
    16861690
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