Support IPv6 adresses without getaddrinfo #4662
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Also, use `CURLRES_IPV6` only for actual DNS resolution, not for IPv6 address support. This makes it possible to connect to IPv6 literals by setting `ENABLE_IPV6` even without `getaddrinfo` support. It also fixes the CMake build when using the synchronous resolver without `getaddrinfo` support. Closes
This makes it possible to recognize and connect to literal IPv6 addresses when `getaddrinfo` is not available, which is already the case for the CMake build. This affects e.g. classic MinGW because it still targets Windows 2000 by default, where `getaddrinfo` is not available, but general IPv6 support is. Instead of checking for `getaddrinfo`, check for `sockaddr_in6` as the CMake build does. Closes
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Can you elaborate on why you want this supported? To me it sounds like we mostly open up for a grey in-between support and not support situation instead of having a clear binary state. Why do we want a curl build that knows about IPv6 but can't resolve IPv6 host names? |
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What I wanted to do was to unify the behavior for the different build systems because I noticed different behavior depending on which one I use with MinGW and older Visual Studio. The CMake, winbuild, DOS, and Visual Studio project builds (and maybe others) don't take I just couldn't find any point in forbidding the user to connect to literal IPv6 addresses at build time if not explicitly disabled with |
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Ok, that makes sense - thanks for the explanation. I'm not overly worried that this will cause new support problems since I suspect this is still a rather niche problem. Most users will still have |
This makes it possible to recognize and connect to literal IPv6 addresses when `getaddrinfo` is not available, which is already the case for the CMake build. This affects e.g. classic MinGW because it still targets Windows 2000 by default, where `getaddrinfo` is not available, but general IPv6 support is. Instead of checking for `getaddrinfo`, check for `sockaddr_in6` as the CMake build does. Closes curl#4662
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I'm pretty sure this caused three test cases to fail when c-ares is used: https://travis-ci.org/curl/curl/jobs/620363654#L5046 |
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Thanks, I'll look into that later today! c-ares was the only backend I didn't test locally. Travis was all green though when I merged this, except for the broken macOS jobs, including the |
This makes the autotools build behave like the CMake build in this regard: support IPv6 addresses (
ENABLE_IPV6) by default as long asAF_INET6andsockaddr_in6are available.getaddrinfois only needed for DNS resolution (CURLRES_IPV6).This also fixes the CMake build with
ENABLE_IPV6set to the defaultON,ENABLE_THREADED_RESOLVERset toOFF, and nogetaddrinfoavailable. The theaded resolver code guards the calls togetaddrinfowithHAVE_GETADDRINFO, but the synchronous resolver code assumes thatCURLRES_IPV6impliesHAVE_GETADDRINFO, which it did only implicitly when using the autotools build.Tested with classic MinGW, which disables
getaddrinfoby default by targeting Windows 2000, and both the threaded and synchronous resolvers.