iptables/0032-libxtables-Implement-notargets-hash-table.patch
Phil Sutter a556128cb3 iptables-1.8.7-29.el9
- libxtables: Boost rule target checks by announcing chain names
- libxtables: Implement notargets hash table
- nft: Reject standard targets as chain names when restoring
- xshared: Merge and share parse_chain()
- xshared: Prefer xtables_chain_protos lookup over getprotoent
- nft: Speed up immediate parsing
- nft: Simplify immediate parsing

Resolves: rhbz#2065330
2022-03-18 11:37:11 +01:00

141 lines
3.3 KiB
Diff

From 7241ebe5cff638bb1422448679d672aa52b3c367 Mon Sep 17 00:00:00 2001
From: Phil Sutter <phil@nwl.cc>
Date: Tue, 15 Dec 2020 15:40:56 +0100
Subject: [PATCH] libxtables: Implement notargets hash table
Target lookup is relatively costly due to the filesystem access. Avoid
this overhead in huge rulesets which contain many chain jumps by caching
the failed lookups into a hashtable for later.
Signed-off-by: Phil Sutter <phil@nwl.cc>
Acked-by: Florian Westphal <fw@strlen.de>
(cherry picked from commit f58b0d7406451afbb4b9b6c7888990c964fa7c79)
---
libxtables/xtables.c | 75 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 75 insertions(+)
diff --git a/libxtables/xtables.c b/libxtables/xtables.c
index a991e4fcc9b92..e8e900e869e1e 100644
--- a/libxtables/xtables.c
+++ b/libxtables/xtables.c
@@ -48,6 +48,7 @@
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv6/ip6_tables.h>
#include <libiptc/libxtc.h>
+#include <libiptc/linux_list.h>
#ifndef NO_SHARED_LIBS
#include <dlfcn.h>
@@ -242,6 +243,71 @@ static void dlreg_free(void)
}
#endif
+struct notarget {
+ struct hlist_node node;
+ char name[];
+};
+
+#define NOTARGET_HSIZE 512
+static struct hlist_head notargets[NOTARGET_HSIZE];
+
+static void notargets_hlist_init(void)
+{
+ int i;
+
+ for (i = 0; i < NOTARGET_HSIZE; i++)
+ INIT_HLIST_HEAD(&notargets[i]);
+}
+
+static void notargets_hlist_free(void)
+{
+ struct hlist_node *pos, *n;
+ struct notarget *cur;
+ int i;
+
+ for (i = 0; i < NOTARGET_HSIZE; i++) {
+ hlist_for_each_entry_safe(cur, pos, n, &notargets[i], node) {
+ hlist_del(&cur->node);
+ free(cur);
+ }
+ }
+}
+
+static uint32_t djb_hash(const char *key)
+{
+ uint32_t i, hash = 5381;
+
+ for (i = 0; i < strlen(key); i++)
+ hash = ((hash << 5) + hash) + key[i];
+
+ return hash;
+}
+
+static struct notarget *notargets_hlist_lookup(const char *name)
+{
+ uint32_t key = djb_hash(name) % NOTARGET_HSIZE;
+ struct hlist_node *node;
+ struct notarget *cur;
+
+ hlist_for_each_entry(cur, node, &notargets[key], node) {
+ if (!strcmp(name, cur->name))
+ return cur;
+ }
+ return NULL;
+}
+
+static void notargets_hlist_insert(const char *name)
+{
+ struct notarget *cur;
+
+ if (!name)
+ return;
+
+ cur = xtables_malloc(sizeof(*cur) + strlen(name) + 1);
+ strcpy(cur->name, name);
+ hlist_add_head(&cur->node, &notargets[djb_hash(name) % NOTARGET_HSIZE]);
+}
+
void xtables_init(void)
{
xtables_libdir = getenv("XTABLES_LIBDIR");
@@ -267,6 +333,8 @@ void xtables_init(void)
return;
}
xtables_libdir = XTABLES_LIBDIR;
+
+ notargets_hlist_init();
}
void xtables_fini(void)
@@ -274,6 +342,7 @@ void xtables_fini(void)
#ifndef NO_SHARED_LIBS
dlreg_free();
#endif
+ notargets_hlist_free();
}
void xtables_set_nfproto(uint8_t nfproto)
@@ -808,6 +877,10 @@ xtables_find_target(const char *name, enum xtables_tryload tryload)
|| strcmp(name, XTC_LABEL_QUEUE) == 0
|| strcmp(name, XTC_LABEL_RETURN) == 0)
name = "standard";
+ /* known non-target? */
+ else if (notargets_hlist_lookup(name) &&
+ tryload != XTF_LOAD_MUST_SUCCEED)
+ return NULL;
/* Trigger delayed initialization */
for (dptr = &xtables_pending_targets; *dptr; ) {
@@ -871,6 +944,8 @@ xtables_find_target(const char *name, enum xtables_tryload tryload)
if (ptr)
ptr->used = 1;
+ else
+ notargets_hlist_insert(name);
return ptr;
}
--
2.34.1