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Drop duplicate fencing requests

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XVM shotguns packets from all interfaces on the system.
This means the server can get the same request from multiple
interfaces at the same time.  This records a history of
fencing requests and drops duplicates for a few seconds.

Signed-off-by: Lon Hohberger <lhh@redhat.com>
This commit is contained in:
Lon Hohberger 2009-08-21 15:31:02 -04:00
parent 4ba33b27b9
commit 2464a326b8
1 changed files with 71 additions and 0 deletions
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71
server/mcast.c
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@ -42,6 +42,7 @@
#include <pthread.h>
#include <nss.h>
#include <libgen.h>
#include <list.h>
#include <simpleconfig.h>
#include <server_plugin.h>
@ -72,9 +73,18 @@ typedef struct _mcast_options {
unsigned int flags;
} mcast_options;
typedef struct _history_node {
list_head();
fence_req_t req;
time_t when;
} history_node;
typedef struct _mcast_info {
uint64_t magic;
void *priv;
history_node *history;
char key[MAX_KEY_LEN];
mcast_options args;
const fence_callbacks_t *cb;
@ -84,6 +94,56 @@ typedef struct _mcast_info {
} mcast_info;
/*
* See if we fenced this node recently (successfully)
* If so, ignore the request for a few seconds.
*
* We purge our history when the entries time out.
*/
static int
check_history(history_node **list, fence_req_t *req)
{
history_node *entry = NULL;
time_t now;
int x;
now = time(NULL);
loop_again:
list_for(list, entry, x) {
if (entry->when < (now - 10)) {
list_remove(list, entry);
free(entry);
goto loop_again;
}
if (entry->req.request == req->request &&
!strcasecmp((const char *)entry->req.domain,
(const char *)req->domain)) {
return 1;
}
}
return 0;
}
static int
record_history(history_node **list, fence_req_t *req)
{
history_node *entry = NULL;
entry = malloc(sizeof(*entry));
if (!entry)
return -1; /* non-fatal */
memset(entry, 0, sizeof(*entry));
memcpy(&entry->req, req, sizeof(*req));
entry->when = time(NULL);
list_insert(list, entry);
return 0;
}
static int
connect_tcp(fence_req_t *req, fence_auth_type_t auth,
void *key, size_t key_len)
@ -181,6 +241,12 @@ do_fence_request_tcp(fence_req_t *req, mcast_info *info)
if (write(fd, &response, 1) < 0) {
perror("write");
}
/* XVM shotguns multicast packets, so we want to avoid
* acting on the same request multiple times if the first
* attempt was successful.
*/
record_history(&info->history, req);
out:
if (fd != -1)
close(fd);
@ -246,6 +312,11 @@ mcast_dispatch(srv_context_t c, struct timeval *timeout)
}
printf("Request %d domain %s\n", data.request, data.domain);
if (check_history(&info->history, &data) == 1) {
printf("We just did this request; dropping packet\n");
return 0;
}
switch(info->args.auth) {
case AUTH_NONE: