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c9b95c0b |
| 19-Jun-2024 |
Stefan Eissing |
lib: graceful connection shutdown When libcurl discards a connection there are two phases this may go through: "shutdown" and "closing". If a connection is aborted, the shutdown phas
lib: graceful connection shutdown When libcurl discards a connection there are two phases this may go through: "shutdown" and "closing". If a connection is aborted, the shutdown phase is skipped and it is closed right away. The connection filters attached to the connection implement the phases in their `do_shutdown()` and `do_close()` callbacks. Filters carry now a `shutdown` flags next to `connected` to keep track of the shutdown operation. Filters are shut down from top to bottom. If a filter is not connected, its shutdown is skipped. Notable filters that *do* something during shutdown are HTTP/2 and TLS. HTTP/2 sends the GOAWAY frame. TLS sends its close notify and expects to receive a close notify from the server. As sends and receives may EAGAIN on the network, a shutdown is often not successful right away and needs to poll the connection's socket(s). To facilitate this, such connections are placed on a new shutdown list inside the connection cache. Since managing this list requires the cooperation of a multi handle, only the connection cache belonging to a multi handle is used. If a connection was in another cache when being discarded, it is removed there and added to the multi's cache. If no multi handle is available at that time, the connection is shutdown and closed in a one-time, best-effort attempt. When a multi handle is destroyed, all connection still on the shutdown list are discarded with a final shutdown attempt and close. In curl debug builds, the environment variable `CURL_GRACEFUL_SHUTDOWN` can be set to make this graceful with a timeout in milliseconds given by the variable. The shutdown list is limited to the max number of connections configured for a multi cache. Set via CURLMOPT_MAX_TOTAL_CONNECTIONS. When the limit is reached, the oldest connection on the shutdown list is discarded. - In multi_wait() and multi_waitfds(), collect all connection caches involved (each transfer might carry its own) into a temporary list. Let each connection cache on the list contribute sockets and POLLIN/OUT events it's connections are waiting for. - in multi_perform() collect the connection caches the same way and let them peform their maintenance. This will make another non-blocking attempt to shutdown all connections on its shutdown list. - for event based multis (multi->socket_cb set), add the sockets and their poll events via the callback. When `multi_socket()` is invoked for a socket not known by an active transfer, forward this to the multi's cache for processing. On closing a connection, remove its socket(s) via the callback. TLS connection filters MUST NOT send close nofity messages in their `do_close()` implementation. The reason is that a TLS close notify signals a success. When a connection is aborted and skips its shutdown phase, the server needs to see a missing close notify to detect something has gone wrong. A graceful shutdown of FTP's data connection is performed implicitly before regarding the upload/download as complete and continuing on the control connection. For FTP without TLS, there is just the socket close happening. But with TLS, the sent/received close notify signals that the transfer is complete and healthy. Servers like `vsftpd` verify that and reject uploads without a TLS close notify. - added test_19_* for shutdown related tests - test_19_01 and test_19_02 test for TCP RST packets which happen without a graceful shutdown and should no longer appear otherwise. - add test_19_03 for handling shutdowns by the server - add test_19_04 for handling shutdowns by curl - add test_19_05 for event based shutdowny by server - add test_30_06/07 and test_31_06/07 for shutdown checks on FTP up- and downloads. Closes #13976
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3fd80c7b |
| 04-Oct-2023 |
Daniel Stenberg |
tests: remove leading spaces from some tags The threee tags `<name>`, `</name>` and `<command>` were frequently used with a leading space that this removes. The reason this habbit is so
tests: remove leading spaces from some tags The threee tags `<name>`, `</name>` and `<command>` were frequently used with a leading space that this removes. The reason this habbit is so widespread in testcases is probably that they have been copy and pasted. Hence, fixing them all now might curb this practice from now on. Closes #12028
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e024d566 |
| 23-May-2023 |
Stefan Eissing |
lib: add CURLINFO_CONN_ID and CURLINFO_XFER_ID - add an `id` long to Curl_easy, -1 on init - once added to a multi (or its own multi), it gets a non-negative number assigned by the
lib: add CURLINFO_CONN_ID and CURLINFO_XFER_ID - add an `id` long to Curl_easy, -1 on init - once added to a multi (or its own multi), it gets a non-negative number assigned by the connection cache - `id` is unique among all transfers using the same cache until reaching LONG_MAX where it will wrap around. So, not unique eternally. - CURLINFO_CONN_ID returns the connection id attached to data or, if none present, data->state.lastconnect_id - variables and type declared in tool for write out Closes #11185
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5f563495 |
| 18-Sep-2021 |
Jeffrey Tolar |
CURLOPT_MAXLIFETIME_CONN: maximum allowed lifetime for conn reuse ... and close connections that are too old instead of reusing them. By default, this behavior is disabled.
CURLOPT_MAXLIFETIME_CONN: maximum allowed lifetime for conn reuse ... and close connections that are too old instead of reusing them. By default, this behavior is disabled. Bug: https://curl.se/mail/lib-2021-09/0058.html Closes #7751
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