CURLOPT_PROTOCOLS [0] was deprecated in libcurl 7.85.0 with
CURLOPT_PROTOCOLS_STR [1] as a replacement.

Well, technically it was only deprecated in 7.87.0, and retroactively
marked as deprecated since 7.85.0 [2]. But CURLOPT_PROTOCOLS_STR exists
since 7.85.0, so that's what we want to use.

This causes compiler warnings and build errors:

  ../src/core/nm-connectivity.c: In function 'do_curl_request':
  ../src/core/nm-connectivity.c:770:5: error: 'CURLOPT_PROTOCOLS' is deprecated: since 7.85.0. Use CURLOPT_PROTOCOLS_STR [-Werror=deprecated-declarations]
    770 |     curl_easy_setopt(ehandle, CURLOPT_PROTOCOLS, CURLPROTO_HTTP | CURLPROTO_HTTPS);
        |     ^~~~~~~~~~~~~~~~
  In file included from ../src/core/nm-connectivity.c:13:
  /usr/include/curl/curl.h:1749:3: note: declared here
   1749 |   CURLOPTDEPRECATED(CURLOPT_PROTOCOLS, CURLOPTTYPE_LONG, 181,
        |   ^~~~~~~~~~~~~~~~~

This patch is largely taken from systemd patch [2].

Based-on-patch-by: Frantisek Sumsal <frantisek@sumsal.cz>

[0] https://curl.se/libcurl/c/CURLOPT_PROTOCOLS.html
[1] https://curl.se/libcurl/c/CURLOPT_PROTOCOLS_STR.html
[2] https://github.com/curl/curl/commit/6967571bf20624bc4cfa68fb8f90cbc53a87c6f2
[3] https://github.com/systemd/systemd/pull/25982/commits/e61a4c0b7c79eabbe4eb50ff2e663734fde769f0

Fixes: 7a1734926a4d ('connectivity,cloud-setup: restrict curl protocols to HTTP and HTTPS')

G_TYPE_CHECK_INSTANCE_CAST() can trigger a "-Wcast-align":

    src/core/devices/nm-device-macvlan.c: In function 'parent_changed_notify':
    /usr/include/glib-2.0/gobject/gtype.h:2421:42: error: cast increases required alignment of target type [-Werror=cast-align]
     2421 | #  define _G_TYPE_CIC(ip, gt, ct)       ((ct*) ip)
          |                                          ^
    /usr/include/glib-2.0/gobject/gtype.h:501:66: note: in expansion of macro '_G_TYPE_CIC'
      501 | #define G_TYPE_CHECK_INSTANCE_CAST(instance, g_type, c_type)    (_G_TYPE_CIC ((instance), (g_type), c_type))
          |                                                                  ^~~~~~~~~~~
    src/core/devices/nm-device-macvlan.h:13:6: note: in expansion of macro 'G_TYPE_CHECK_INSTANCE_CAST'
       13 |     (G_TYPE_CHECK_INSTANCE_CAST((obj), NM_TYPE_DEVICE_MACVLAN, NMDeviceMacvlan))
          |      ^~~~~~~~~~~~~~~~~~~~~~~~~~

Avoid that by using _NM_G_TYPE_CHECK_INSTANCE_CAST().

This can only be done for our internal usages. The public headers
of libnm are not changed.

The label "try_again" is only reached by one goto. So it was correct
and sufficient to reset the state only there.

It is still error prone. The slighlty clearer approach is to clear
the state at each begin of the "try_again" step.

There should be no change in behavior.

I didn't confirm, but an optimizing compiler should (could) be able
to see that the cleanup is only necessary on retry, and generate the
same code as before. In any case, we should write code that is easier
to read, not optimize for something that a compiler should be able to
optimize itself.

There should be no change in behavior, but this way seems nicer.
Now _nmc_mangle_connection() doesn't return FALSE, it always
will try to mangle the connection and requires the caller to
first check whether that is appropriate.

Just move some code outside of _nmc_mangle_connection() and let
the caller check for the skip first.

The point is consistency, as the caller already does some checks to
whether skip the reapply. So it should do all the checks, so that
"mangle" never fails/skips.

Externally added IP addresses/routes should be preserved by
nm-cloud-setup. This allows other tools to also configure the interface
and the Reapply() call from nm-cloud-setup would not interfere
with those tools.

https://bugzilla.redhat.com/show_bug.cgi?id=2132754

- name things related to `in_addr_t`, `struct in6_addr`, `NMIPAddr` as
  `nm_ip4_addr_*()`, `nm_ip6_addr_*()`, `nm_ip_addr_*()`, respectively.

- we have a wrapper `nm_inet_ntop()` for `inet_ntop()`. This name
  of our wrapper is chosen to be familiar with the libc underlying
  function. With this, also name functions that are about string
  representations of addresses `nm_inet_*()`, `nm_inet4_*()`,
  `nm_inet6_*()`. For example, `nm_inet_parse_str()`,
  `nm_inet_is_normalized()`.

<<<<

  R() {
     git grep -l "$1" | xargs sed -i "s/\<$1\>/$2/g"
  }

  R NM_CMP_DIRECT_IN4ADDR_SAME_PREFIX          NM_CMP_DIRECT_IP4_ADDR_SAME_PREFIX
  R NM_CMP_DIRECT_IN6ADDR_SAME_PREFIX          NM_CMP_DIRECT_IP6_ADDR_SAME_PREFIX
  R NM_UTILS_INET_ADDRSTRLEN                   NM_INET_ADDRSTRLEN
  R _nm_utils_inet4_ntop                       nm_inet4_ntop
  R _nm_utils_inet6_ntop                       nm_inet6_ntop
  R _nm_utils_ip4_get_default_prefix           nm_ip4_addr_get_default_prefix
  R _nm_utils_ip4_get_default_prefix0          nm_ip4_addr_get_default_prefix0
  R _nm_utils_ip4_netmask_to_prefix            nm_ip4_addr_netmask_to_prefix
  R _nm_utils_ip4_prefix_to_netmask            nm_ip4_addr_netmask_from_prefix
  R nm_utils_inet4_ntop_dup                    nm_inet4_ntop_dup
  R nm_utils_inet6_ntop_dup                    nm_inet6_ntop_dup
  R nm_utils_inet_ntop                         nm_inet_ntop
  R nm_utils_inet_ntop_dup                     nm_inet_ntop_dup
  R nm_utils_ip4_address_clear_host_address    nm_ip4_addr_clear_host_address
  R nm_utils_ip4_address_is_link_local         nm_ip4_addr_is_link_local
  R nm_utils_ip4_address_is_loopback           nm_ip4_addr_is_loopback
  R nm_utils_ip4_address_is_zeronet            nm_ip4_addr_is_zeronet
  R nm_utils_ip4_address_same_prefix           nm_ip4_addr_same_prefix
  R nm_utils_ip4_address_same_prefix_cmp       nm_ip4_addr_same_prefix_cmp
  R nm_utils_ip6_address_clear_host_address    nm_ip6_addr_clear_host_address
  R nm_utils_ip6_address_same_prefix           nm_ip6_addr_same_prefix
  R nm_utils_ip6_address_same_prefix_cmp       nm_ip6_addr_same_prefix_cmp
  R nm_utils_ip6_is_ula                        nm_ip6_addr_is_ula
  R nm_utils_ip_address_same_prefix            nm_ip_addr_same_prefix
  R nm_utils_ip_address_same_prefix_cmp        nm_ip_addr_same_prefix_cmp
  R nm_utils_ip_is_site_local                  nm_ip_addr_is_site_local
  R nm_utils_ipaddr_is_normalized              nm_inet_is_normalized
  R nm_utils_ipaddr_is_valid                   nm_inet_is_valid
  R nm_utils_ipx_address_clear_host_address    nm_ip_addr_clear_host_address
  R nm_utils_parse_inaddr                      nm_inet_parse_str
  R nm_utils_parse_inaddr_bin                  nm_inet_parse_bin
  R nm_utils_parse_inaddr_bin_full             nm_inet_parse_bin_full
  R nm_utils_parse_inaddr_prefix               nm_inet_parse_with_prefix_str
  R nm_utils_parse_inaddr_prefix_bin           nm_inet_parse_with_prefix_bin
  R test_nm_utils_ip6_address_same_prefix      test_nm_ip_addr_same_prefix

  ./contrib/scripts/nm-code-format.sh -F

We have two variants of the function: nm_utils_ip4_netmask_to_prefix()
and _nm_utils_ip4_netmask_to_prefix(). The former only exists because it
is public API in libnm. Internally, only use the latter.

From config_iface_data->get_config_data we have access to the other pointer
already. No need to allocate a user data.

(cherry picked from commit 7d71aff24770ad8ba6c6bc16a83d4d9e2544bd45)

Use a union, it makes more sense.

Note that with union, C's struct initialization might not sufficiently
set all fields to the default. In practice yes, but theoretically in C
a NULL pointer and floats must not have all zero bits, so the following
is not guaranteed to work:

    struct {
        int some_field;
        union {
             void *v_ptr;
             int v_int;
        };
    } variable = {
        .some_field = 24,
    };

    assert(variable.union.v_ptr == 0);
    assert(variable.union.v_int == 0);

When initializing the variable, we should not rely on automatically
initialize all union members correctly. It cannot at the same time
set NULL pointers and zero integers -- well, on our architectures it
probably can, but not as far as guaranteed by C language.
We need to know which union field we are going to use and initialize
it explicitly.
As we know the provider type, we can do that.

Also, maybe in the future we need special free/unref calls when
destroying the type specific data in NMCSProviderGetConfigIfaceData.
As we know the provider, we can.

Note that having type specific data in NMCSProviderGetConfigIfaceData.priv
is a layering violation. But it is still simpler than implementing
type specific handlers (callbacks) or tracking the data somewhere else.
After all, we know at compile time all the existing provider types.

(cherry picked from commit 1e696c7e93c14bc2ea7bfdcf4a655621ceb4e862)