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platform: cleanup detecting kernel support for IFA_FLAGS and IPv6LL

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- cache the result in NMPlatformPrivate. No need to call the virtual
  function every time. The result is not ever going to change.

- if we are unable to detect support, assume support. Those features
  were added quite a while ago to kernel, we should default to "support".
  Note, that we detect support based on the presence of the absence of
  certain netlink flags. That means, we will still detect no support.
  The only moment when we actually use the fallback value, is when we
  didn't encounter an RTM_NEWADDR or AF_INET6-IFLA_AF_SPEC message yet,
  which would be very unusual, because we fill the cache initially and
  usually will have some addresses there.

- for no strong reason, track "undetected" as numerical value zero,
  and "support"/"no-support" as 1/-1. We already did that previously for
  _support_user_ipv6ll, so this just unifies the implementations.
  The minor reason is that this puts @_support_user_ipv6ll to the BSS
  section and allows us to omit initializing priv->check_support_user_ipv6ll_cached
  in platforms constructor.

- detect _support_kernel_extended_ifa_flags also based on IPv4
  RTM_NEWADDR messages. Originally, extended flags were added for IPv6,
  and later to IPv4 as well. Once we see an IPv4 message with IFA_FLAGS,
  we know we have support.
This commit is contained in:
Thomas Haller
2017-08-16 11:58:57 +02:00
parent 48bc116c20
commit 8670aacc7c
2 changed files with 63 additions and 47 deletions
Download Patch File Download Diff File Expand all files Collapse all files

76
src/platform/nm-linux-platform.c
View File

@@ -297,60 +297,62 @@ wait_for_nl_response_to_string (WaitForNlResponseResult seq_result, char *buf, g
static int _support_user_ipv6ll = 0;
#define _support_user_ipv6ll_still_undecided() (G_UNLIKELY (_support_user_ipv6ll == 0))
static void
_support_user_ipv6ll_detect (struct nlattr **tb)
{
gboolean supported;
nm_assert (_support_user_ipv6ll_still_undecided ());
supported = !!tb[IFLA_INET6_ADDR_GEN_MODE];
_support_user_ipv6ll = supported ? 1 : -1;
_LOG2D ("kernel-support: IFLA_INET6_ADDR_GEN_MODE: %s",
supported ? "detected" : "not detected");
}
static gboolean
_support_user_ipv6ll_get (void)
{
if (_support_user_ipv6ll_still_undecided ()) {
_support_user_ipv6ll = -1;
_LOG2D ("kernel-support: IFLA_INET6_ADDR_GEN_MODE: %s", "failed to detect; assume no support");
return FALSE;
}
return _support_user_ipv6ll > 0;
}
static void
_support_user_ipv6ll_detect (struct nlattr **tb)
{
if (_support_user_ipv6ll_still_undecided ()) {
gboolean supported = !!tb[IFLA_INET6_ADDR_GEN_MODE];
_support_user_ipv6ll = supported ? 1 : -1;
_LOG2D ("kernel-support: IFLA_INET6_ADDR_GEN_MODE: %s",
supported ? "detected" : "not detected");
_support_user_ipv6ll = 1;
_LOG2D ("kernel-support: IFLA_INET6_ADDR_GEN_MODE: %s", "failed to detect; assume support");
}
return _support_user_ipv6ll >= 0;
}
/*****************************************************************************
* extended IFA_FLAGS support
*****************************************************************************/
static int _support_kernel_extended_ifa_flags = -1;
static int _support_kernel_extended_ifa_flags = 0;
#define _support_kernel_extended_ifa_flags_still_undecided() (G_UNLIKELY (_support_kernel_extended_ifa_flags == -1))
#define _support_kernel_extended_ifa_flags_still_undecided() (G_UNLIKELY (_support_kernel_extended_ifa_flags == 0))
static void
_support_kernel_extended_ifa_flags_detect (struct nl_msg *msg)
{
struct nlmsghdr *msg_hdr;
gboolean support;
if (!_support_kernel_extended_ifa_flags_still_undecided ())
return;
nm_assert (_support_kernel_extended_ifa_flags_still_undecided ());
nm_assert (msg);
msg_hdr = nlmsg_hdr (msg);
if (msg_hdr->nlmsg_type != RTM_NEWADDR)
return;
/* the extended address flags are only set for AF_INET6 */
if (((struct ifaddrmsg *) nlmsg_data (msg_hdr))->ifa_family != AF_INET6)
nm_assert (msg_hdr && msg_hdr->nlmsg_type == RTM_NEWADDR);
/* IFA_FLAGS is set for IPv4 and IPv6 addresses. It was added first to IPv6,
* but if we encounter an IPv4 address with IFA_FLAGS, we surely have support. */
if (NM_IN_SET (((struct ifaddrmsg *) nlmsg_data (msg_hdr))->ifa_family, AF_INET, AF_INET6))
return;
/* see if the nl_msg contains the IFA_FLAGS attribute. If it does,
* we assume, that the kernel supports extended flags, IFA_F_MANAGETEMPADDR
* and IFA_F_NOPREFIXROUTE (they were added together).
**/
_support_kernel_extended_ifa_flags = !!nlmsg_find_attr (msg_hdr, sizeof (struct ifaddrmsg), IFA_FLAGS);
_LOG2D ("kernel-support: extended-ifa-flags: %s", _support_kernel_extended_ifa_flags ? "detected" : "not detected");
support = !!nlmsg_find_attr (msg_hdr, sizeof (struct ifaddrmsg), IFA_FLAGS);
_support_kernel_extended_ifa_flags = support ? 1 : -1;
_LOG2D ("kernel-support: extended-ifa-flags: %s", support ? "detected" : "not detected");
}
static gboolean
@@ -360,7 +362,7 @@ _support_kernel_extended_ifa_flags_get (void)
_LOG2D ("kernel-support: extended-ifa-flags: %s", "unable to detect kernel support for handling IPv6 temporary addresses. Assume support");
_support_kernel_extended_ifa_flags = 1;
}
return _support_kernel_extended_ifa_flags;
return _support_kernel_extended_ifa_flags >= 0;
}
/******************************************************************
@@ -978,7 +980,8 @@ _parse_af_inet6 (NMPlatform *platform,
/* Hack to detect support addrgenmode of the kernel. We only parse
* netlink messages that we receive from kernel, hence this check
* is valid. */
_support_user_ipv6ll_detect (tb);
if (_support_user_ipv6ll_still_undecided ())
_support_user_ipv6ll_detect (tb);
if (tb[IFLA_INET6_ADDR_GEN_MODE]) {
i6_addr_gen_mode_inv = _nm_platform_uint8_inv (nla_get_u8 (tb[IFLA_INET6_ADDR_GEN_MODE]));
@@ -2992,7 +2995,7 @@ sysctl_get (NMPlatform *platform, const char *pathid, int dirfd, const char *pat
static gboolean
check_support_kernel_extended_ifa_flags (NMPlatform *platform)
{
g_return_val_if_fail (NM_IS_LINUX_PLATFORM (platform), FALSE);
nm_assert (NM_IS_LINUX_PLATFORM (platform));
return _support_kernel_extended_ifa_flags_get ();
}
@@ -3000,7 +3003,7 @@ check_support_kernel_extended_ifa_flags (NMPlatform *platform)
static gboolean
check_support_user_ipv6ll (NMPlatform *platform)
{
g_return_val_if_fail (NM_IS_LINUX_PLATFORM (platform), FALSE);
nm_assert (NM_IS_LINUX_PLATFORM (platform));
return _support_user_ipv6ll_get ();
}
@@ -3863,7 +3866,8 @@ event_valid_msg (NMPlatform *platform, struct nl_msg *msg, gboolean handle_event
msghdr = nlmsg_hdr (msg);
if (_support_kernel_extended_ifa_flags_still_undecided () && msghdr->nlmsg_type == RTM_NEWADDR)
if ( _support_kernel_extended_ifa_flags_still_undecided ()
&& msghdr->nlmsg_type == RTM_NEWADDR)
_support_kernel_extended_ifa_flags_detect (msg);
if (!handle_events)
@@ -4423,15 +4427,15 @@ link_set_user_ipv6ll_enabled (NMPlatform *platform, int ifindex, gboolean enable
nm_auto_nlmsg struct nl_msg *nlmsg = NULL;
guint8 mode = enabled ? NM_IN6_ADDR_GEN_MODE_NONE : NM_IN6_ADDR_GEN_MODE_EUI64;
_LOGD ("link: change %d: user-ipv6ll: set IPv6 address generation mode to %s",
ifindex,
nm_platform_link_inet6_addrgenmode2str (mode, NULL, 0));
if (!_support_user_ipv6ll_get ()) {
_LOGD ("link: change %d: user-ipv6ll: not supported", ifindex);
return NM_PLATFORM_ERROR_OPNOTSUPP;
}
_LOGD ("link: change %d: user-ipv6ll: set IPv6 address generation mode to %s",
ifindex,
nm_platform_link_inet6_addrgenmode2str (mode, NULL, 0));
nlmsg = _nl_msg_new_link (RTM_NEWLINK,
0,
ifindex,