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Increase default queue items allocation limit from 512 to 4096 items

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to avoid terrible unpredicted effects for netgraph operation of their
exhaustion while allocating control messages.
Add separate configurable 512 items limit for data items allocation
for DoS/overload protection.

Discussed with:	julian
This commit is contained in:
Alexander Motin 2008-03-05 22:12:34 +00:00
parent ac188d74d6
commit ed75521f5b
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=176849
1 changed files with 16 additions and 2 deletions
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18
sys/netgraph/ng_base.c
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@ -2993,11 +2993,16 @@ ng_generic_msg(node_p here, item_p item, hook_p lasthook)
************************************************************************/
uma_zone_t ng_qzone;
static int maxalloc = 512; /* limit the damage of a leak */
static int maxalloc = 4096;/* limit the damage of a leak */
static int maxdata = 512; /* limit the damage of a DoS */
static int useddata = 0;
TUNABLE_INT("net.graph.maxalloc", &maxalloc);
SYSCTL_INT(_net_graph, OID_AUTO, maxalloc, CTLFLAG_RDTUN, &maxalloc,
0, "Maximum number of queue items to allocate");
TUNABLE_INT("net.graph.maxdata", &maxdata);
SYSCTL_INT(_net_graph, OID_AUTO, maxdata, CTLFLAG_RW | CTLFLAG_TUN, &maxdata,
0, "Maximum number of queue data items to allocate");
#ifdef NETGRAPH_DEBUG
static TAILQ_HEAD(, ng_item) ng_itemlist = TAILQ_HEAD_INITIALIZER(ng_itemlist);
@ -3048,6 +3053,7 @@ ng_free_item(item_p item)
*/
switch (item->el_flags & NGQF_TYPE) {
case NGQF_DATA:
atomic_subtract_int(&useddata, 1);
/* If we have an mbuf still attached.. */
NG_FREE_M(_NGI_M(item));
break;
@ -3474,6 +3480,11 @@ ng_package_data(struct mbuf *m, int flags)
{
item_p item;
if (atomic_fetchadd_int(&useddata, 1) >= maxdata) {
atomic_subtract_int(&useddata, 1);
NG_FREE_M(m);
return (NULL);
}
if ((item = ng_getqblk(flags)) == NULL) {
NG_FREE_M(m);
return (NULL);
@ -3708,8 +3719,11 @@ ng_send_fn2(node_p node, hook_p hook, item_p pitem, ng_item_fn2 *fn, void *arg1,
if (pitem == NULL || (flags & NG_REUSE_ITEM) == 0) {
if ((item = ng_getqblk(flags)) == NULL)
return (ENOMEM);
} else
} else {
if ((pitem->el_flags & NGQF_TYPE) == NGQF_DATA)
atomic_subtract_int(&useddata, 1);
item = pitem;
}
item->el_flags = NGQF_FN2 | NGQF_WRITER;
NG_NODE_REF(node); /* and one for the item */