connect: Fix happy eyeballs logic for IPv4-only builds #168
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
(trynextip) - Don't try the "other" protocol family unless IPv6 is available. In an IPv4-only build the other family can only be IPv6 which is unavailable. This change essentially stops IPv4-only builds from attempting the "happy eyeballs" secondary parallel connection that is supposed to be used by the "other" address family. Prior to this change in IPv4-only builds that secondary parallel connection attempt could be erroneously used by the same family (IPv4) which caused a bug where every address after the first for a host could be tried twice, often in parallel. This change fixes that bug. An example of the bug is shown below. Assume MTEST resolves to 3 addresses 127.0.0.2, 127.0.0.3 and 127.0.0.4: * STATE: INIT => CONNECT handle 0x64f4b0; line 1046 (connection #-5000) * Rebuilt URL to: http://MTEST/ * Added connection 0. The cache now contains 1 members * STATE: CONNECT => WAITRESOLVE handle 0x64f4b0; line 1083 (connection #0) * Trying 127.0.0.2... * STATE: WAITRESOLVE => WAITCONNECT handle 0x64f4b0; line 1163 (connection #0) * Trying 127.0.0.3... * connect to 127.0.0.2 port 80 failed: Connection refused * Trying 127.0.0.3... * connect to 127.0.0.3 port 80 failed: Connection refused * Trying 127.0.0.4... * connect to 127.0.0.3 port 80 failed: Connection refused * Trying 127.0.0.4... * connect to 127.0.0.4 port 80 failed: Connection refused * connect to 127.0.0.4 port 80 failed: Connection refused * Failed to connect to MTEST port 80: Connection refused * Closing connection 0 * The cache now contains 0 members * Expire cleared curl: (7) Failed to connect to MTEST port 80: Connection refused The bug was born in commit curl/curl@2d435c7.
bagder
pushed a commit
that referenced
this pull request
Mar 16, 2015
Bug: #168 (trynextip) - Don't try the "other" protocol family unless IPv6 is available. In an IPv4-only build the other family can only be IPv6 which is unavailable. This change essentially stops IPv4-only builds from attempting the "happy eyeballs" secondary parallel connection that is supposed to be used by the "other" address family. Prior to this change in IPv4-only builds that secondary parallel connection attempt could be erroneously used by the same family (IPv4) which caused a bug where every address after the first for a host could be tried twice, often in parallel. This change fixes that bug. An example of the bug is shown below. Assume MTEST resolves to 3 addresses 127.0.0.2, 127.0.0.3 and 127.0.0.4: * STATE: INIT => CONNECT handle 0x64f4b0; line 1046 (connection #-5000) * Rebuilt URL to: http://MTEST/ * Added connection 0. The cache now contains 1 members * STATE: CONNECT => WAITRESOLVE handle 0x64f4b0; line 1083 (connection #0) * Trying 127.0.0.2... * STATE: WAITRESOLVE => WAITCONNECT handle 0x64f4b0; line 1163 (connection #0) * Trying 127.0.0.3... * connect to 127.0.0.2 port 80 failed: Connection refused * Trying 127.0.0.3... * connect to 127.0.0.3 port 80 failed: Connection refused * Trying 127.0.0.4... * connect to 127.0.0.3 port 80 failed: Connection refused * Trying 127.0.0.4... * connect to 127.0.0.4 port 80 failed: Connection refused * connect to 127.0.0.4 port 80 failed: Connection refused * Failed to connect to MTEST port 80: Connection refused * Closing connection 0 * The cache now contains 0 members * Expire cleared curl: (7) Failed to connect to MTEST port 80: Connection refused The bug was born in commit 2d435c7.
This pull request was closed.
Sign up for free
to subscribe to this conversation on GitHub.
Already have an account?
Sign in.
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
(trynextip)
IPv4-only build the other family can only be IPv6 which is unavailable.
This change essentially stops IPv4-only builds from attempting the
"happy eyeballs" secondary parallel connection that is supposed to be
used by the "other" address family.
Prior to this change in IPv4-only builds that secondary parallel
connection attempt could be erroneously used by the same family (IPv4)
which caused a bug where every address after the first for a host could
be tried twice, often in parallel. This change fixes that bug. An
example of the bug is shown below.
Assume MTEST resolves to 3 addresses 127.0.0.2, 127.0.0.3 and 127.0.0.4:
(connection #0)
(connection #0)
curl: (7) Failed to connect to MTEST port 80: Connection refused
The bug was born in commit 2d435c7.