[systemd-devel] [PATCH 4/6] make in_addr_from_string() accept ipv4 addresses even when using AF_INET6

[Shawn Landden]

On Sun, Mar 15, 2015 at 1:07 PM, Zbigniew Jędrzejewski-Szmek <
zbyszek at in.waw.pl> wrote:

> On Wed, Mar 11, 2015 at 08:13:47AM -0700, Shawn Landden wrote:
> > if we are going to have a function to fix up the deficiencies of
> > inet_pton(), better go all the way.
> > ---
> >  src/shared/in-addr-util.c | 17 +++++++++++++++++
> >  src/shared/in-addr-util.h |  1 +
> >  2 files changed, 18 insertions(+)
> >
> > diff --git a/src/shared/in-addr-util.c b/src/shared/in-addr-util.c
> > index ade4012..b7532a6 100644
> > --- a/src/shared/in-addr-util.c
> > +++ b/src/shared/in-addr-util.c
> > @@ -206,7 +206,18 @@ int in_addr_to_string(int family, const union
> in_addr_union *u, char **ret) {
> >          return 0;
> >  }
> >
> > +struct in6_addr in_addr_to_in6_addr(struct in_addr ipv4) {
> > +        struct in6_addr r = { { {
> > +                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xFF, 0xFF, 0, 0, 0, 0
> > +        } } };
> > +
> > +        r.s6_addr32[3] = ipv4.s_addr;
> > +
> > +        return r;
> > +}
> > +
> >  int in_addr_from_string(int family, const char *s, void *ret) {
> > +        struct in_addr v4mapped;
> >
> >          assert(s);
> >          assert(ret);
> > @@ -214,6 +225,12 @@ int in_addr_from_string(int family, const char *s,
> void *ret) {
> >          if (!IN_SET(family, AF_INET, AF_INET6))
> >                  return -EAFNOSUPPORT;
> >
> > +        if (family == AF_INET6)
> > +                if (inet_pton(AF_INET, s, &v4mapped) == 1) {
> > +                        *((struct in6_addr *)ret) =
> in_addr_to_in6_addr(v4mapped);
> > +                        return 0;
> > +                }
> > +
> Hm, IIUC, an ipv6 address was specified, but the user gave an ipv4 address.
> Automatically converting seems like a way to entice confusion...
>
> Except that the linux kernel supports binding to ipv4 this way, (see
ipv6(7)).

In the inet_pton man page:

BUGS
       AF_INET6 does not recognize IPv4 addresses.  An explicit IPv4-mapped
IPv6 address must be supplied in src instead.


Zbyszek
>
> >          errno = 0;
> >          if (inet_pton(family, s, ret) <= 0)
> >                  return errno ? -errno : -EINVAL;
> > diff --git a/src/shared/in-addr-util.h b/src/shared/in-addr-util.h
> > index 8b3a07c..f140ec9 100644
> > --- a/src/shared/in-addr-util.h
> > +++ b/src/shared/in-addr-util.h
> > @@ -37,6 +37,7 @@ int in_addr_equal(int family, const union
> in_addr_union *a, const union in_addr_
> >  int in_addr_prefix_intersect(int family, const union in_addr_union *a,
> unsigned aprefixlen, const union in_addr_union *b, unsigned bprefixlen);
> >  int in_addr_prefix_next(int family, union in_addr_union *u, unsigned
> prefixlen);
> >  int in_addr_to_string(int family, const union in_addr_union *u, char
> **ret);
> > +struct in6_addr in_addr_to_in6_addr(struct in_addr ipv4) _const_;
> >  int in_addr_from_string(int family, const char *s, void *ret);
> >  int in_addr_from_string_auto(const char *s, int *family, union
> in_addr_union *ret);
> >  unsigned char in_addr_netmask_to_prefixlen(const struct in_addr *addr);
> > --
> > 2.2.1.209.g41e5f3a
> >
> > _______________________________________________
> > systemd-devel mailing list
> > systemd-devel at lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/systemd-devel
> _______________________________________________
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>



-- 
Shawn Landden
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