[PATCH] ipvsadm: fix list_daemon to handle master/backup status in either position

[PATCH] ipvsadm: fix list_daemon to handle master/backup status in either position

[Ryan O'Hara]

[-- Attachment #1: Type: text/plain, Size: 871 bytes --]

Attached is a patch that fixes the list_daemon function such that it 
does not assume that the master sync daemon status is always in the 
first position and master sync daemon status is always in the second 
position.

If libipvs uses the netlink interface to retrieve sync daemon status, 
the results are not guaranteed to follow this ordering. As explained in 
a previous email, if libipvs uses the netlink interface to retrieve sync 
daemon status while only a backup sync daemon is running, the backup 
sync daemon status will but in the first position (index 0). This 
differs from the getsockopt interface, which would always put master 
sync daemon status in first position and backup sync daemon status in 
the second position, even when only backup sync daemon exists. Solution 
is to make ipvsadm check both elements of the array for master and backup.

Ryan


[-- Attachment #2: ipvsadm-1.26-fix_list_daemon.patch --]
[-- Type: text/plain, Size: 871 bytes --]

Index: ipvsadm.c
===================================================================
--- ipvsadm.c	(revision 77)
+++ ipvsadm.c	(working copy)
@@ -1631,16 +1631,19 @@
 static void list_daemon(void)
 {
 	ipvs_daemon_t *u;
+	int i;
 
 	if (!(u = ipvs_get_daemon()))
 		exit(1);
 
-	if (u[0].state & IP_VS_STATE_MASTER)
-		printf("master sync daemon (mcast=%s, syncid=%d)\n",
-		       u[0].mcast_ifn, u[0].syncid);
-	if (u[1].state & IP_VS_STATE_BACKUP)
-		printf("backup sync daemon (mcast=%s, syncid=%d)\n",
-		       u[1].mcast_ifn, u[1].syncid);
+	for (i = 0; i < 2; i++) {
+		if (u[i].state & IP_VS_STATE_MASTER)
+			printf("master sync daemon (mcast=%s, syncid=%d)\n",
+			       u[i].mcast_ifn, u[i].syncid);
+		if (u[i].state & IP_VS_STATE_MASTER)
+			printf("master sync daemon (mcast=%s, syncid=%d)\n",
+			       u[i].mcast_ifn, u[i].syncid);
+	}
 	free(u);
 }
 

Re: [PATCH] ipvsadm: fix list_daemon to handle master/backup status in either position

[Alexander Holler]

Am 09.02.2012 16:50, schrieb Ryan O'Hara:
> Attached is a patch that fixes the list_daemon function such that it
> does not assume that the master sync daemon status is always in the
> first position and master sync daemon status is always in the second
> position.
>
> If libipvs uses the netlink interface to retrieve sync daemon status,
> the results are not guaranteed to follow this ordering. As explained in
> a previous email, if libipvs uses the netlink interface to retrieve sync
> daemon status while only a backup sync daemon is running, the backup
> sync daemon status will but in the first position (index 0). This
> differs from the getsockopt interface, which would always put master
> sync daemon status in first position and backup sync daemon status in
> the second position, even when only backup sync daemon exists. Solution
> is to make ipvsadm check both elements of the array for master and backup.
>
> Ryan

I've fixed that through letting the netlink-api reporting the same as 
without netlink.

Don't know what solutions should be prefered.

Regards,

Alexander

---
  keepalived/libipvs-2.6/libipvs.c |   11 ++++++-----
  1 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/keepalived/libipvs-2.6/libipvs.c 
b/keepalived/libipvs-2.6/libipvs.c
index ea5e851..6bee837 100644
--- a/keepalived/libipvs-2.6/libipvs.c
+++ b/keepalived/libipvs-2.6/libipvs.c
@@ -1003,12 +1003,9 @@ static int ipvs_daemon_parse_cb(struct nl_msg 
*msg, void *arg)
  	struct nlattr *attrs[IPVS_CMD_ATTR_MAX + 1];
  	struct nlattr *daemon_attrs[IPVS_DAEMON_ATTR_MAX + 1];
  	ipvs_daemon_t *u = (ipvs_daemon_t *)arg;
+	__u32 state;
  	int i = 0;

-	/* We may get two daemons.  If we've already got one, this is the 
second */
-	if (u[0].state)
-		i = 1;

Re: [PATCH] ipvsadm: fix list_daemon to handle master/backup status in either position

[Ryan O'Hara]

On 02/09/2012 11:42 AM, Alexander Holler wrote:
> Am 09.02.2012 16:50, schrieb Ryan O'Hara:
>> Attached is a patch that fixes the list_daemon function such that it
>> does not assume that the master sync daemon status is always in the
>> first position and master sync daemon status is always in the second
>> position.
>>
>> If libipvs uses the netlink interface to retrieve sync daemon status,
>> the results are not guaranteed to follow this ordering. As explained in
>> a previous email, if libipvs uses the netlink interface to retrieve sync
>> daemon status while only a backup sync daemon is running, the backup
>> sync daemon status will but in the first position (index 0). This
>> differs from the getsockopt interface, which would always put master
>> sync daemon status in first position and backup sync daemon status in
>> the second position, even when only backup sync daemon exists. Solution
>> is to make ipvsadm check both elements of the array for master and
>> backup.
>>
>> Ryan
>
> I've fixed that through letting the netlink-api reporting the same as
> without netlink.
>
> Don't know what solutions should be prefered.
>
> Regards,
>
> Alexander

Thanks for the patch. After taking a close look at your patch, I believe 
it will fix the problem.

I'm also unsure about which is the preferred solution. I decided to fix 
it in ipvsadm directly because (it seemed) ipvsadm was making incorrect 
assumptions about the master/backup sync daemon status being in at a 
specific index. That said, I'm find with your patch. Keeping the strict 
ordering is just as reasonable.

Ryan