inet/getaddrinfo: fix AF_V4MAPPED behavior for non IPv6 host resolution

When trying to resolve a hostname by getaddrinfo() using some specific
settings, it will always return -EAI_NONAME (Name or service not known).

To reproduce this behavior, you need to request an IPv6 address with the
additional AF_V4MAPPED flag set from an non IPv6 capable hostname. If
you choose a IPv4/IPv6 capable hostname like google.com, everything
works fine.

This patch is more or less a port [1][2] from the glibc and their behavior
for the AF_V4MAPPED flag. To test the bug you can use the following snippet.

---- 8< ----

int ret;
struct addrinfo* result;
struct addrinfo hints;

memset(&hints, 0, sizeof(struct addrinfo));
hints.ai_family = AF_INET6;
hints.ai_flags = AI_V4MAPPED;

ret = getaddrinfo("test.com", NULL, &hints, &result);
printf("getaddrinfo(): %i", ret);

---- 8< ----

[1] https://sourceware.org/git/?p=glibc.git;a=commit;f=sysdeps/posix/getaddrinfo.c;h=925c3c5c71596c02f7e58a0ffcdcaae44eb065c1
[2] https://sourceware.org/git/?p=glibc.git;a=commit;f=sysdeps/posix/getaddrinfo.c;h=28977c2c1acb789660ad47e0d88e42486059c916

Signed-off-by: Alexander Wenzel <alexander.wenzel@qsc.de>

0 files changed, 0 insertions, 0 deletions