Description
iputils-ping supports IDN resolv via getaddrinfo() glibc functionality, there's no need to link it directly to libidn2 to get IDN support
shared lib links:
% ldd `which ping`
linux-vdso.so.1 (0x00007ffca51db000)
libcap.so.2 => /lib/x86_64-linux-gnu/libcap.so.2 (0x00007df4f1ed5000)
libidn2.so.0 => /lib/x86_64-linux-gnu/libidn2.so.0 (0x00007df4f1eb3000)
libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007df4f1c00000)
libunistring.so.5 => /lib/x86_64-linux-gnu/libunistring.so.5 (0x00007df4f1a53000)
/lib64/ld-linux-x86-64.so.2 (0x00007df4f1f20000)
a test version (https://github.com/yvs2014/iputils) built without explicit link against libidn2 works totally in the same way
(via implicit libc getaddrinfo() calls to libidn2 if current locale is unicode compat)
% ldd _build/ping/ping
linux-vdso.so.1 (0x00007ffe499cd000)
libcap.so.2 => /lib/x86_64-linux-gnu/libcap.so.2 (0x00007050c22be000)
libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007050c2000000)
/lib64/ld-linux-x86-64.so.2 (0x00007050c230f000)
The only point where this explicit link against libidn2 needed is idn2_lookup_ul() call from ping/node_info.c.
Which in turn is used for -N subject-name and -N subject-fqdn (if I got it correctly -N is IP6 nodeinfo query client functionality).
Is that worth to make explicit link to libidn optional?
A couple ways that are tested:
- optional support for IP6 IDN nodeinfo queries (it works)
- replace idn2_lookup_ul() with libc idna_to_dns_encoding() (it works too, but it is internal libc interface and can be changed in anytime)
- optional build support for RFC4620 client in general (not tried yet)
p.s. to test ip6-nodeinfo functionality (-N option) it needs to build ninfod server or some other one with similar interface.