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platform: return failure reason from route-add and return only netlink response

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Let nm_platform_ip_route_add() and friends return an NMPlatformError
failure reason.

Also, do_add_addrroute() did not return the response from kernel.
Instead, it determined success/failure based on the presence of the
object in the cache. That is racy and does not allow to give a failure
reason from kernel.

Instead, determine success solely based on the netlink reply from
kernel. The received errno shall be authorative, there is no need
to second guess the response.

There is a problem that netlink is not a reliable protocol. In case
of receive buffer overflow, the response is lost and we don't know
whether the command succeeded (it likely did). It's unclear how to fix
that, but for now just return "unspecified" error. We probably avoid
that already by having a huge buffer size.

Also, downgrade the error message to <warn> level. <error> is really
for bugs only.
This commit is contained in:
Thomas Haller
2017-08-21 15:33:57 +02:00
parent fa7fafe8fd
commit 774c8a811e
7 changed files with 60 additions and 51 deletions
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54
src/platform/nm-linux-platform.c
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@@ -265,6 +265,16 @@ static gboolean event_handler_read_netlink (NMPlatform *platform, gboolean wait_
/*****************************************************************************/
static NMPlatformError
wait_for_nl_response_to_plerr (WaitForNlResponseResult seq_result)
{
if (seq_result == WAIT_FOR_NL_RESPONSE_RESULT_RESPONSE_OK)
return NM_PLATFORM_ERROR_SUCCESS;
if (seq_result < 0)
return (NMPlatformError) seq_result;
return NM_PLATFORM_ERROR_NETLINK;
}
static const char *
wait_for_nl_response_to_string (WaitForNlResponseResult seq_result, char *buf, gsize buf_size)
{
@@ -4223,14 +4233,12 @@ do_add_link_with_lookup (NMPlatform *platform,
return !!obj;
}
static gboolean
static NMPlatformError
do_add_addrroute (NMPlatform *platform, const NMPObject *obj_id, struct nl_msg *nlmsg)
{
WaitForNlResponseResult seq_result = WAIT_FOR_NL_RESPONSE_RESULT_UNKNOWN;
int nle;
char s_buf[256];
const NMPObject *obj;
NMPCache *cache = nm_platform_get_cache (platform);
nm_assert (NM_IN_SET (NMP_OBJECT_GET_TYPE (obj_id),
NMP_OBJECT_TYPE_IP4_ADDRESS, NMP_OBJECT_TYPE_IP6_ADDRESS,
@@ -4244,7 +4252,7 @@ do_add_addrroute (NMPlatform *platform, const NMPObject *obj_id, struct nl_msg *
NMP_OBJECT_GET_CLASS (obj_id)->obj_type_name,
nmp_object_to_string (obj_id, NMP_OBJECT_TO_STRING_ID, NULL, 0),
nl_geterror (nle), -nle);
return FALSE;
return NM_PLATFORM_ERROR_NETLINK;
}
delayed_action_handle_all (platform, FALSE);
@@ -4253,30 +4261,26 @@ do_add_addrroute (NMPlatform *platform, const NMPObject *obj_id, struct nl_msg *
_NMLOG (seq_result == WAIT_FOR_NL_RESPONSE_RESULT_RESPONSE_OK
? LOGL_DEBUG
: LOGL_ERR,
: LOGL_WARN,
"do-add-%s[%s]: %s",
NMP_OBJECT_GET_CLASS (obj_id)->obj_type_name,
nmp_object_to_string (obj_id, NMP_OBJECT_TO_STRING_ID, NULL, 0),
wait_for_nl_response_to_string (seq_result, s_buf, sizeof (s_buf)));
/* In rare cases, the object is not yet ready as we received the ACK from
* kernel. Need to refetch.
*
* We want to safe the expensive refetch, thus we look first into the cache
* whether the object exists.
*
* FIXME: if the object already existed previously, we might not notice a
* missing update. It's not clear how to fix that reliably without refechting
* all the time. */
obj = nmp_cache_lookup_obj (cache, obj_id);
if (!obj) {
do_request_one_type (platform, NMP_OBJECT_GET_TYPE (obj_id));
obj = nmp_cache_lookup_obj (cache, obj_id);
if (NMP_OBJECT_GET_TYPE (obj_id) == NMP_OBJECT_TYPE_IP6_ADDRESS) {
/* In rare cases, the object is not yet ready as we received the ACK from
* kernel. Need to refetch.
*
* We want to safe the expensive refetch, thus we look first into the cache
* whether the object exists.
*
* rh#1484434 */
if (!nmp_cache_lookup_obj (nm_platform_get_cache (platform),
obj_id))
do_request_one_type (platform, NMP_OBJECT_GET_TYPE (obj_id));
}
/* Adding is only successful, if kernel reported success *and* we have the
* expected object in cache afterwards. */
return obj && seq_result == WAIT_FOR_NL_RESPONSE_RESULT_RESPONSE_OK;
return wait_for_nl_response_to_plerr (seq_result);
}
static gboolean
@@ -5910,7 +5914,7 @@ ip4_address_add (NMPlatform *platform,
label);
nmp_object_stackinit_id_ip4_address (&obj_id, ifindex, addr, plen, peer_addr);
return do_add_addrroute (platform, &obj_id, nlmsg);
return do_add_addrroute (platform, &obj_id, nlmsg) == NM_PLATFORM_ERROR_SUCCESS;
}
static gboolean
@@ -5940,7 +5944,7 @@ ip6_address_add (NMPlatform *platform,
NULL);
nmp_object_stackinit_id_ip6_address (&obj_id, ifindex, &addr);
return do_add_addrroute (platform, &obj_id, nlmsg);
return do_add_addrroute (platform, &obj_id, nlmsg) == NM_PLATFORM_ERROR_SUCCESS;
}
static gboolean
@@ -5995,7 +5999,7 @@ ip6_address_delete (NMPlatform *platform, int ifindex, struct in6_addr addr, gui
/*****************************************************************************/
static gboolean
static NMPlatformError
ip_route_add (NMPlatform *platform,
NMPNlmFlags flags,
int addr_family,
@@ -6019,7 +6023,7 @@ ip_route_add (NMPlatform *platform,
nlmsg = _nl_msg_new_route (RTM_NEWROUTE, flags, &obj);
if (!nlmsg)
g_return_val_if_reached (FALSE);
g_return_val_if_reached (NM_PLATFORM_ERROR_BUG);
return do_add_addrroute (platform, &obj, nlmsg);
}