Fix bug where last few bytes on socket go unread #642
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… error event arrives from the file-descriptor, since the HANG_UP event may come when there's still a lot more data to read on the socket.
Codecov ReportAttention: Patch coverage is
Additional details and impacted files@@ Coverage Diff @@
## main #642 +/- ##
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- Coverage 80.11% 80.05% -0.07%
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Files 28 28
Lines 5965 5967 +2
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- Hits 4779 4777 -2
- Misses 1186 1190 +4 ☔ View full report in Codecov by Sentry. |
graebm
commented
Jun 3, 2024
| @@ -122,6 +122,10 @@ static void s_on_readable_notification(struct aws_socket *socket, int error_code | |||
| */ | |||
| static void s_do_read(struct socket_handler *socket_handler) { | |||
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| if (socket_handler->shutdown_in_progress) { | |||
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This function didn't have any bugs. I'm just simplifying the code.
When this code was written, shutdown_in_progress could change half-way through the function, but since 2019 shutdown is always queued, so moving this check to the top of the function, instead of having it at 3 separate parts of a complicated flow
graebm
commented
Jun 3, 2024
Comment on lines
-223
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| if (error_code && !socket_handler->shutdown_in_progress) { | ||
| aws_channel_shutdown(socket_handler->slot->channel, error_code); | ||
| } |
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This is the only line that truly HAD to change to fix this bug
DmitriyMusatkin
approved these changes
Jun 3, 2024
graebm
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Jun 5, 2024
**Issue:** awscrt.s3.S3Client is occasionally seeing errors when the server sends an HTTP response with a `Connection: close` header (meaning it intends to close the connection after the response is sent). The server is sending the full response, then immediately hanging up. But the last few bytes of the response never make it to the HTTP client. **Description of changes:** Update submodules, bringing in this fix: awslabs/aws-c-io#642 ``` aws-c-auth v0.7.17 -> v0.7.22 aws-c-cal v0.6.11 -> v0.6.15 aws-c-common v0.9.15 -> v0.9.20 aws-c-http v0.8.1 -> v0.8.2 aws-c-io v0.14.7 -> v0.14.9 aws-c-mqtt v0.10.3 -> v0.10.4 aws-c-s3 v0.5.7 -> v0.5.10 aws-c-sdkutils v0.1.15 -> v0.1.16 s2n v1.4.11 -> v1.4.15 ```
This was referenced Jun 11, 2024
graebm
added a commit
to awslabs/aws-crt-swift
that referenced
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Jun 12, 2024
**Issue:** We see occasional errors when the server sends an HTTP response with a `Connection: close` header (meaning it intends to close the connection after the response is sent). The server is sending the full response, then immediately hanging up. But the last few bytes of the response never make it to the HTTP client. **Description of changes:** Update submodules, bringing in this fix: awslabs/aws-c-io#642 ``` aws-c-auth v0.7.16 -> v0.7.22 aws-c-cal v0.6.10 -> v0.6.15 aws-c-common v0.9.14 -> v0.9.21 aws-c-http v0.8.1 -> v0.8.2 aws-c-io v0.14.6 -> v0.14.9 aws-c-sdkutils v0.1.15 -> v0.1.16 s2n v1.4.8 -> v1.4.16 ```
graebm
added a commit
to awslabs/aws-crt-cpp
that referenced
this pull request
Jun 12, 2024
**Issue:** aws-c-s3 is occasionally seeing errors when the server sends an HTTP response with a `Connection: close` header (meaning it intends to close the connection after the response is sent). The server is sending the full response, then immediately hanging up. But the last few bytes of the response never make it to the HTTP client. **Description of changes:** Update submodules, bringing in this fix: awslabs/aws-c-io#642 ``` aws-c-common v0.9.19 -> v0.9.21 aws-c-http v0.8.1 -> v0.8.2 aws-c-io v0.14.8 -> v0.14.9 aws-c-s3 v0.5.9 -> v0.5.10 aws-lc v1.28.0 -> v1.29.0 s2n v1.4.15 -> v1.4.16 ```
graebm
added a commit
to awslabs/aws-crt-java
that referenced
this pull request
Jun 13, 2024
**Issue:** We're occasionally seeing errors when the server sends an HTTP response with a `Connection: close` header (meaning it intends to close the connection after the response is sent). The server is sending the full response, then immediately hanging up. But the last few bytes of the response never make it to the HTTP client. **Description of changes:** Update submodules, bringing in this fix: awslabs/aws-c-io#642 ``` aws-c-auth v0.7.17 -> v0.7.22 aws-c-cal v0.6.11 -> v0.6.15 aws-c-common v0.9.15 -> v0.9.21 aws-c-http v0.8.1 -> v0.8.2 aws-c-io v0.14.7 -> v0.14.9 aws-c-mqtt v0.10.3 -> v0.10.4 aws-c-sdkutils v0.1.15 -> v0.1.16 s2n v1.4.11 -> v1.4.16 ```
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Issue:
aws-c-s3 is occasionally seeing errors when the server sends an HTTP response with a
Connection: closeheader (meaning it intends to close the connection after the response is sent). The server is sending the full response, then immediately hanging up. But the last few bytes of the response never make it to the HTTP client.Diagnosis:
If a peer closed their socket immediately after the last few bytes were sent, our socket code wasn't always reading those last few bytes.
On Linux, if a socket has unread data AND the peer has closed their side, the event from epoll has 2 flags set:
EPOLLIN|EPOLLRDHUP. This means "the socket is has data to read AND the other side is closed (or half-closed) and won't be sending any more data".Our socket handler code kinda did the right thing by "attempting" to read from the socket before shutting down the channel. But if the downstream read window reached 0, that "attempt" wouldn't read all the data.
Description of changes:
The socket handler no longer shuts down the channel in response to an error event. Instead, the error event queues more reads to happen. And only when
read()reports that the socket is finished (due to error or EOF), will the socket handler shut down the channel.By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.