Hi,
As promised, here is my fix for the string match which makes it work for
SMP boxen. The skip/shift tables are now per-CPU.
Please review.
Thanks.
--
// Gianni Tedesco <[EMAIL PROTECTED]>
Segmentation fault (core dumped)
--- userspace/patch-o-matic/extra/string.patch Mon Nov 12 08:19:29 2001
+++ userspace/patch-o-matic/extra/string.patch Thu Feb 21 20:28:37 2002
@@ -1,6 +1,6 @@
-diff -urN linux/include/linux/netfilter_ipv4/ipt_string.h
linux.new/include/linux/netfilter_ipv4/ipt_string.h
---- linux/include/linux/netfilter_ipv4/ipt_string.h Thu Jan 1 01:00:00 1970
-+++ linux.new/include/linux/netfilter_ipv4/ipt_string.h Wed May 2 12:23:00
2001
+diff -urN linux.orig/include/linux/netfilter_ipv4/ipt_string.h
+linux/include/linux/netfilter_ipv4/ipt_string.h
+--- linux.orig/include/linux/netfilter_ipv4/ipt_string.h Thu Jan 1 01:00:00
+1970
++++ linux/include/linux/netfilter_ipv4/ipt_string.h Thu Feb 21 20:26:23 2002
@@ -0,0 +1,21 @@
+#ifndef _IPT_STRING_H
+#define _IPT_STRING_H
@@ -23,15 +23,18 @@
+};
+
+#endif /* _IPT_STRING_H */
-diff -urN linux/net/ipv4/netfilter/ipt_string.c
linux.new/net/ipv4/netfilter/ipt_string.c
---- linux/net/ipv4/netfilter/ipt_string.c Thu Jan 1 01:00:00 1970
-+++ linux.new/net/ipv4/netfilter/ipt_string.c Wed May 2 12:44:21 2001
-@@ -0,0 +1,158 @@
+diff -urN linux.orig/net/ipv4/netfilter/ipt_string.c
+linux/net/ipv4/netfilter/ipt_string.c
+--- linux.orig/net/ipv4/netfilter/ipt_string.c Thu Jan 1 01:00:00 1970
++++ linux/net/ipv4/netfilter/ipt_string.c Thu Feb 21 20:26:09 2002
+@@ -0,0 +1,214 @@
+/* Kernel module to match a string into a packet.
+ *
+ * Copyright (C) 2000 Emmanuel Roger <[EMAIL PROTECTED]>
+ *
+ * ChangeLog
++ * 19.02.2002: Gianni Tedesco <[EMAIL PROTECTED]>
++ * Fixed SMP re-entrancy problem using per-cpu data areas
++ * for the skip/shift tables.
+ * 02.05.2001: Gianni Tedesco <[EMAIL PROTECTED]>
+ * Fixed kernel panic, due to overrunning boyer moore string
+ * tables. Also slightly tweaked heuristic for deciding what
@@ -43,6 +46,7 @@
+ * packet basis.
+ */
+
++#include <linux/smp.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/file.h>
@@ -51,18 +55,27 @@
+#include <linux/netfilter_ipv4/ip_tables.h>
+#include <linux/netfilter_ipv4/ipt_string.h>
+
-+MODULE_LICENSE("GPL");
++struct string_per_cpu {
++ int *skip;
++ int *shift;
++ int *len;
++};
+
-+int skip[BM_MAX_HLEN];
-+int shift[BM_MAX_HLEN];
++struct string_per_cpu *bm_string_data=NULL;
+
+/* Boyer Moore Sublinear string search - VERY FAST */
+char *search_sublinear (char *needle, char *haystack, int needle_len, int
+haystack_len)
+{
+ int M1, right_end, sk, sh;
-+ int ended, j, len[BM_MAX_HLEN];
-+ int i;
++ int ended, j, i;
+
++ int *skip, *shift, *len;
++
++ /* use data suitable for this CPU */
++ shift=bm_string_data[smp_processor_id()].shift;
++ skip=bm_string_data[smp_processor_id()].skip;
++ len=bm_string_data[smp_processor_id()].len;
++
+ /* Setup skip/shift tables */
+ M1 = right_end = needle_len-1;
+ for (i = 0; i < BM_MAX_HLEN; i++) skip[i] = needle_len;
@@ -93,7 +106,7 @@
+
+ sk = skip[haystack[right_end - i]];
+ sh = shift[i];
-+ right_end = max(right_end - i + sk, right_end + sh);
++ right_end = max(int, right_end - i + sk, right_end + sh);
+ }
+
+ return NULL;
@@ -170,17 +183,60 @@
+ return 1;
+}
+
++void string_freeup_data(void)
++{
++ int c;
++
++ if ( bm_string_data ) {
++ for(c=0; c<smp_num_cpus; c++) {
++ if ( bm_string_data[c].shift ) kfree(bm_string_data[c].shift);
++ if ( bm_string_data[c].skip ) kfree(bm_string_data[c].skip);
++ if ( bm_string_data[c].len ) kfree(bm_string_data[c].len);
++ }
++ kfree(bm_string_data);
++ }
++}
++
+static struct ipt_match string_match
+= { { NULL, NULL }, "string", &match, &checkentry, NULL, THIS_MODULE };
+
+static int __init init(void)
+{
-+ return ipt_register_match(&string_match);
++ int c;
++ size_t tlen;
++ size_t alen;
++
++ tlen=sizeof(struct string_per_cpu)*smp_num_cpus;
++ alen=sizeof(int)*BM_MAX_HLEN;
++
++ /* allocate array of structures */
++ if ( !(bm_string_data=kmalloc(tlen,GFP_KERNEL)) ) {
++ return 0;
++ }
++
++ memset(bm_string_data, 0, tlen);
++
++ /* allocate our skip/shift tables */
++ for(c=0; c<smp_num_cpus; c++) {
++ if ( !(bm_string_data[c].shift=kmalloc(alen, GFP_KERNEL)) )
++ goto alloc_fail;
++ if ( !(bm_string_data[c].skip=kmalloc(alen, GFP_KERNEL)) )
++ goto alloc_fail;
++ if ( !(bm_string_data[c].len=kmalloc(alen, GFP_KERNEL)) )
++ goto alloc_fail;
++ }
++
++ return ipt_register_match(&string_match);
++
++alloc_fail:
++ string_freeup_data();
++ return 0;
+}
+
+static void __exit fini(void)
+{
-+ ipt_unregister_match(&string_match);
++ ipt_unregister_match(&string_match);
++ string_freeup_data();
+}
+
+module_init(init);
