up to 5.19.4

[packages/kernel.git] / kernel-layer7.patch

diff -urNp -x '*.orig' linux-5.11/include/linux/netfilter/xt_layer7.h linux-5.11/include/linux/netfilter/xt_layer7.h
--- linux-5.11/include/linux/netfilter/xt_layer7.h	1970-01-01 01:00:00.000000000 +0100
+++ linux-5.11/include/linux/netfilter/xt_layer7.h	2021-02-24 13:21:48.338440845 +0100
@@ -0,0 +1,13 @@
+#ifndef _XT_LAYER7_H
+#define _XT_LAYER7_H
+
+#define MAX_PATTERN_LEN 8192
+#define MAX_PROTOCOL_LEN 256
+
+struct xt_layer7_info {
+    char protocol[MAX_PROTOCOL_LEN];
+    char pattern[MAX_PATTERN_LEN];
+    u_int8_t invert;
+};
+
+#endif /* _XT_LAYER7_H */
diff -urNp -x '*.orig' linux-5.11/include/net/netfilter/nf_conntrack.h linux-5.11/include/net/netfilter/nf_conntrack.h
--- linux-5.11/include/net/netfilter/nf_conntrack.h	2021-02-14 23:32:24.000000000 +0100
+++ linux-5.11/include/net/netfilter/nf_conntrack.h	2021-02-24 13:21:48.338440845 +0100
@@ -103,6 +103,22 @@ struct nf_conn {
 	/* Extensions */
 	struct nf_ct_ext *ext;
 
+#if defined(CONFIG_NETFILTER_XT_MATCH_LAYER7) || \
+	defined(CONFIG_NETFILTER_XT_MATCH_LAYER7_MODULE)
+	struct {
+		/*
+		 * e.g. "http". NULL before decision. "unknown" after decision
+		 * if no match.
+		 */
+		char *app_proto;
+		/*
+		 * application layer data so far. NULL after match decision.
+		 */
+		char *app_data;
+		unsigned int app_data_len;
+	} layer7;
+#endif
+
 	/* Storage reserved for other modules, must be the last member */
 	union nf_conntrack_proto proto;
 };
diff -urNp -x '*.orig' linux-5.11/net/netfilter/Kconfig linux-5.11/net/netfilter/Kconfig
--- linux-5.11/net/netfilter/Kconfig	2021-02-14 23:32:24.000000000 +0100
+++ linux-5.11/net/netfilter/Kconfig	2021-02-24 13:21:48.335107407 +0100
@@ -1562,6 +1562,27 @@ config NETFILTER_XT_MATCH_STATE
 
 	  To compile it as a module, choose M here.  If unsure, say N.
 
+config NETFILTER_XT_MATCH_LAYER7
+	tristate '"layer7" match support'
+	depends on NETFILTER_XTABLES
+	depends on EXPERIMENTAL && (IP_NF_CONNTRACK || NF_CONNTRACK)
+	help
+	  Say Y if you want to be able to classify connections (and their
+	  packets) based on regular expression matching of their application
+	  layer data.   This is one way to classify applications such as
+	  peer-to-peer filesharing systems that do not always use the same
+	  port.
+
+	  To compile it as a module, choose M here.  If unsure, say N.
+
+
+config NETFILTER_XT_MATCH_LAYER7_DEBUG
+        bool 'Layer 7 debugging output'
+        depends on NETFILTER_XT_MATCH_LAYER7
+        help
+          Say Y to get lots of debugging output.
+
+
 config NETFILTER_XT_MATCH_STATISTIC
 	tristate '"statistic" match support'
 	depends on NETFILTER_ADVANCED
diff -urNp -x '*.orig' linux-5.11/net/netfilter/Makefile linux-5.11/net/netfilter/Makefile
--- linux-5.11/net/netfilter/Makefile	2021-02-14 23:32:24.000000000 +0100
+++ linux-5.11/net/netfilter/Makefile	2021-02-24 13:21:48.335107407 +0100
@@ -204,6 +204,7 @@ obj-$(CONFIG_NETFILTER_XT_MATCH_RECENT)
 obj-$(CONFIG_NETFILTER_XT_MATCH_SCTP) += xt_sctp.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_SOCKET) += xt_socket.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_STATE) += xt_state.o
+obj-$(CONFIG_NETFILTER_XT_MATCH_LAYER7) += xt_layer7.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_STATISTIC) += xt_statistic.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_STRING) += xt_string.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_TCPMSS) += xt_tcpmss.o
diff -urNp -x '*.orig' linux-5.11/net/netfilter/nf_conntrack_standalone.c linux-5.11/net/netfilter/nf_conntrack_standalone.c
--- linux-5.11/net/netfilter/nf_conntrack_standalone.c	2021-02-14 23:32:24.000000000 +0100
+++ linux-5.11/net/netfilter/nf_conntrack_standalone.c	2021-02-24 13:21:48.338440845 +0100
@@ -366,6 +366,12 @@ static int ct_seq_show(struct seq_file *
 	ct_show_zone(s, ct, NF_CT_DEFAULT_ZONE_DIR);
 	ct_show_delta_time(s, ct);
 
+#if defined(CONFIG_NETFILTER_XT_MATCH_LAYER7) || defined(CONFIG_NETFILTER_XT_MATCH_LAYER7_MODULE)
+	if(ct->layer7.app_proto &&
+           seq_printf(s, "l7proto=%s ", ct->layer7.app_proto))
+		return -ENOSPC;
+#endif
+
 	seq_printf(s, "use=%u\n", refcount_read(&ct->ct_general.use));
 
 	if (seq_has_overflowed(s))
diff -urNp -x '*.orig' linux-5.11/net/netfilter/regexp/regexp.c linux-5.11/net/netfilter/regexp/regexp.c
--- linux-5.11/net/netfilter/regexp/regexp.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-5.11/net/netfilter/regexp/regexp.c	2021-02-24 13:21:48.335107407 +0100
@@ -0,0 +1,1197 @@
+/*
+ * regcomp and regexec -- regsub and regerror are elsewhere
+ * @(#)regexp.c	1.3 of 18 April 87
+ *
+ *	Copyright (c) 1986 by University of Toronto.
+ *	Written by Henry Spencer.  Not derived from licensed software.
+ *
+ *	Permission is granted to anyone to use this software for any
+ *	purpose on any computer system, and to redistribute it freely,
+ *	subject to the following restrictions:
+ *
+ *	1. The author is not responsible for the consequences of use of
+ *		this software, no matter how awful, even if they arise
+ *		from defects in it.
+ *
+ *	2. The origin of this software must not be misrepresented, either
+ *		by explicit claim or by omission.
+ *
+ *	3. Altered versions must be plainly marked as such, and must not
+ *		be misrepresented as being the original software.
+ *
+ * Beware that some of this code is subtly aware of the way operator
+ * precedence is structured in regular expressions.  Serious changes in
+ * regular-expression syntax might require a total rethink.
+ *
+ * This code was modified by Ethan Sommer to work within the kernel
+ * (it now uses kmalloc etc..)
+ *
+ * Modified slightly by Matthew Strait to use more modern C.
+ */
+
+#include "regexp.h"
+#include "regmagic.h"
+
+/* added by ethan and matt.  Lets it work in both kernel and user space.
+(So iptables can use it, for instance.)  Yea, it goes both ways... */
+#if __KERNEL__
+  #define malloc(foo) kmalloc(foo,GFP_ATOMIC)
+#else
+  #define printk(format,args...) printf(format,##args)
+#endif
+
+void regerror(char * s)
+{
+        printk("<3>Regexp: %s\n", s);
+        /* NOTREACHED */
+}
+
+/*
+ * The "internal use only" fields in regexp.h are present to pass info from
+ * compile to execute that permits the execute phase to run lots faster on
+ * simple cases.  They are:
+ *
+ * regstart	char that must begin a match; '\0' if none obvious
+ * reganch	is the match anchored (at beginning-of-line only)?
+ * regmust	string (pointer into program) that match must include, or NULL
+ * regmlen	length of regmust string
+ *
+ * Regstart and reganch permit very fast decisions on suitable starting points
+ * for a match, cutting down the work a lot.  Regmust permits fast rejection
+ * of lines that cannot possibly match.  The regmust tests are costly enough
+ * that regcomp() supplies a regmust only if the r.e. contains something
+ * potentially expensive (at present, the only such thing detected is * or +
+ * at the start of the r.e., which can involve a lot of backup).  Regmlen is
+ * supplied because the test in regexec() needs it and regcomp() is computing
+ * it anyway.
+ */
+
+/*
+ * Structure for regexp "program".  This is essentially a linear encoding
+ * of a nondeterministic finite-state machine (aka syntax charts or
+ * "railroad normal form" in parsing technology).  Each node is an opcode
+ * plus a "next" pointer, possibly plus an operand.  "Next" pointers of
+ * all nodes except BRANCH implement concatenation; a "next" pointer with
+ * a BRANCH on both ends of it is connecting two alternatives.  (Here we
+ * have one of the subtle syntax dependencies:  an individual BRANCH (as
+ * opposed to a collection of them) is never concatenated with anything
+ * because of operator precedence.)  The operand of some types of node is
+ * a literal string; for others, it is a node leading into a sub-FSM.  In
+ * particular, the operand of a BRANCH node is the first node of the branch.
+ * (NB this is *not* a tree structure:  the tail of the branch connects
+ * to the thing following the set of BRANCHes.)  The opcodes are:
+ */
+
+/* definition	number	opnd?	meaning */
+#define	END	0	/* no	End of program. */
+#define	BOL	1	/* no	Match "" at beginning of line. */
+#define	EOL	2	/* no	Match "" at end of line. */
+#define	ANY	3	/* no	Match any one character. */
+#define	ANYOF	4	/* str	Match any character in this string. */
+#define	ANYBUT	5	/* str	Match any character not in this string. */
+#define	BRANCH	6	/* node	Match this alternative, or the next... */
+#define	BACK	7	/* no	Match "", "next" ptr points backward. */
+#define	EXACTLY	8	/* str	Match this string. */
+#define	NOTHING	9	/* no	Match empty string. */
+#define	STAR	10	/* node	Match this (simple) thing 0 or more times. */
+#define	PLUS	11	/* node	Match this (simple) thing 1 or more times. */
+#define	OPEN	20	/* no	Mark this point in input as start of #n. */
+			/*	OPEN+1 is number 1, etc. */
+#define	CLOSE	30	/* no	Analogous to OPEN. */
+
+/*
+ * Opcode notes:
+ *
+ * BRANCH	The set of branches constituting a single choice are hooked
+ *		together with their "next" pointers, since precedence prevents
+ *		anything being concatenated to any individual branch.  The
+ *		"next" pointer of the last BRANCH in a choice points to the
+ *		thing following the whole choice.  This is also where the
+ *		final "next" pointer of each individual branch points; each
+ *		branch starts with the operand node of a BRANCH node.
+ *
+ * BACK		Normal "next" pointers all implicitly point forward; BACK
+ *		exists to make loop structures possible.
+ *
+ * STAR,PLUS	'?', and complex '*' and '+', are implemented as circular
+ *		BRANCH structures using BACK.  Simple cases (one character
+ *		per match) are implemented with STAR and PLUS for speed
+ *		and to minimize recursive plunges.
+ *
+ * OPEN,CLOSE	...are numbered at compile time.
+ */
+
+/*
+ * A node is one char of opcode followed by two chars of "next" pointer.
+ * "Next" pointers are stored as two 8-bit pieces, high order first.  The
+ * value is a positive offset from the opcode of the node containing it.
+ * An operand, if any, simply follows the node.  (Note that much of the
+ * code generation knows about this implicit relationship.)
+ *
+ * Using two bytes for the "next" pointer is vast overkill for most things,
+ * but allows patterns to get big without disasters.
+ */
+#define	OP(p)	(*(p))
+#define	NEXT(p)	(((*((p)+1)&0377)<<8) + (*((p)+2)&0377))
+#define	OPERAND(p)	((p) + 3)
+
+/*
+ * See regmagic.h for one further detail of program structure.
+ */
+
+
+/*
+ * Utility definitions.
+ */
+#ifndef CHARBITS
+#define	UCHARAT(p)	((int)*(unsigned char *)(p))
+#else
+#define	UCHARAT(p)	((int)*(p)&CHARBITS)
+#endif
+
+#define	FAIL(m)	{ regerror(m); return(NULL); }
+#define	ISMULT(c)	((c) == '*' || (c) == '+' || (c) == '?')
+#define	META	"^$.[()|?+*\\"
+
+/*
+ * Flags to be passed up and down.
+ */
+#define	HASWIDTH	01	/* Known never to match null string. */
+#define	SIMPLE		02	/* Simple enough to be STAR/PLUS operand. */
+#define	SPSTART		04	/* Starts with * or +. */
+#define	WORST		0	/* Worst case. */
+
+/*
+ * Global work variables for regcomp().
+ */
+struct match_globals {
+char *reginput;		/* String-input pointer. */
+char *regbol;		/* Beginning of input, for ^ check. */
+char **regstartp;	/* Pointer to startp array. */
+char **regendp;		/* Ditto for endp. */
+char *regparse;		/* Input-scan pointer. */
+int regnpar;		/* () count. */
+char regdummy;
+char *regcode;		/* Code-emit pointer; &regdummy = don't. */
+long regsize;		/* Code size. */
+};
+
+/*
+ * Forward declarations for regcomp()'s friends.
+ */
+#ifndef STATIC
+#define	STATIC	static
+#endif
+STATIC char *reg(struct match_globals *g, int paren,int *flagp);
+STATIC char *regbranch(struct match_globals *g, int *flagp);
+STATIC char *regpiece(struct match_globals *g, int *flagp);
+STATIC char *regatom(struct match_globals *g, int *flagp);
+STATIC char *regnode(struct match_globals *g, char op);
+STATIC char *regnext(struct match_globals *g, char *p);
+STATIC void regc(struct match_globals *g, char b);
+STATIC void reginsert(struct match_globals *g, char op, char *opnd);
+STATIC void regtail(struct match_globals *g, char *p, char *val);
+STATIC void regoptail(struct match_globals *g, char *p, char *val);
+
+
+__kernel_size_t my_strcspn(const char *s1,const char *s2)
+{
+        char *scan1;
+        char *scan2;
+        int count;
+
+        count = 0;
+        for (scan1 = (char *)s1; *scan1 != '\0'; scan1++) {
+                for (scan2 = (char *)s2; *scan2 != '\0';)       /* ++ moved down. */
+                        if (*scan1 == *scan2++)
+                                return(count);
+                count++;
+        }
+        return(count);
+}
+
+/*
+ - regcomp - compile a regular expression into internal code
+ *
+ * We can't allocate space until we know how big the compiled form will be,
+ * but we can't compile it (and thus know how big it is) until we've got a
+ * place to put the code.  So we cheat:  we compile it twice, once with code
+ * generation turned off and size counting turned on, and once "for real".
+ * This also means that we don't allocate space until we are sure that the
+ * thing really will compile successfully, and we never have to move the
+ * code and thus invalidate pointers into it.  (Note that it has to be in
+ * one piece because free() must be able to free it all.)
+ *
+ * Beware that the optimization-preparation code in here knows about some
+ * of the structure of the compiled regexp.
+ */
+regexp *
+regcomp(char *exp,int *patternsize)
+{
+	register regexp *r;
+	register char *scan;
+	register char *longest;
+	register int len;
+	int flags;
+	struct match_globals g;
+	
+	/* commented out by ethan
+	   extern char *malloc();
+	*/
+
+	if (exp == NULL)
+		FAIL("NULL argument");
+
+	/* First pass: determine size, legality. */
+	g.regparse = exp;
+	g.regnpar = 1;
+	g.regsize = 0L;
+	g.regcode = &g.regdummy;
+	regc(&g, MAGIC);
+	if (reg(&g, 0, &flags) == NULL)
+		return(NULL);
+
+	/* Small enough for pointer-storage convention? */
+	if (g.regsize >= 32767L)		/* Probably could be 65535L. */
+		FAIL("regexp too big");
+
+	/* Allocate space. */
+	*patternsize=sizeof(regexp) + (unsigned)g.regsize;
+	r = (regexp *)malloc(sizeof(regexp) + (unsigned)g.regsize);
+	if (r == NULL)
+		FAIL("out of space");
+
+	/* Second pass: emit code. */
+	g.regparse = exp;
+	g.regnpar = 1;
+	g.regcode = r->program;
+	regc(&g, MAGIC);
+	if (reg(&g, 0, &flags) == NULL)
+		return(NULL);
+
+	/* Dig out information for optimizations. */
+	r->regstart = '\0';	/* Worst-case defaults. */
+	r->reganch = 0;
+	r->regmust = NULL;
+	r->regmlen = 0;
+	scan = r->program+1;			/* First BRANCH. */
+	if (OP(regnext(&g, scan)) == END) {		/* Only one top-level choice. */
+		scan = OPERAND(scan);
+
+		/* Starting-point info. */
+		if (OP(scan) == EXACTLY)
+			r->regstart = *OPERAND(scan);
+		else if (OP(scan) == BOL)
+			r->reganch++;
+
+		/*
+		 * If there's something expensive in the r.e., find the
+		 * longest literal string that must appear and make it the
+		 * regmust.  Resolve ties in favor of later strings, since
+		 * the regstart check works with the beginning of the r.e.
+		 * and avoiding duplication strengthens checking.  Not a
+		 * strong reason, but sufficient in the absence of others.
+		 */
+		if (flags&SPSTART) {
+			longest = NULL;
+			len = 0;
+			for (; scan != NULL; scan = regnext(&g, scan))
+				if (OP(scan) == EXACTLY && strlen(OPERAND(scan)) >= len) {
+					longest = OPERAND(scan);
+					len = strlen(OPERAND(scan));
+				}
+			r->regmust = longest;
+			r->regmlen = len;
+		}
+	}
+
+	return(r);
+}
+
+/*
+ - reg - regular expression, i.e. main body or parenthesized thing
+ *
+ * Caller must absorb opening parenthesis.
+ *
+ * Combining parenthesis handling with the base level of regular expression
+ * is a trifle forced, but the need to tie the tails of the branches to what
+ * follows makes it hard to avoid.
+ */
+static char *
+reg(struct match_globals *g, int paren, int *flagp /* Parenthesized? */ )
+{
+	register char *ret;
+	register char *br;
+	register char *ender;
+	register int parno = 0; /* 0 makes gcc happy */
+	int flags;
+
+	*flagp = HASWIDTH;	/* Tentatively. */
+
+	/* Make an OPEN node, if parenthesized. */
+	if (paren) {
+		if (g->regnpar >= NSUBEXP)
+			FAIL("too many ()");
+		parno = g->regnpar;
+		g->regnpar++;
+		ret = regnode(g, OPEN+parno);
+	} else
+		ret = NULL;
+
+	/* Pick up the branches, linking them together. */
+	br = regbranch(g, &flags);
+	if (br == NULL)
+		return(NULL);
+	if (ret != NULL)
+		regtail(g, ret, br);	/* OPEN -> first. */
+	else
+		ret = br;
+	if (!(flags&HASWIDTH))
+		*flagp &= ~HASWIDTH;
+	*flagp |= flags&SPSTART;
+	while (*g->regparse == '|') {
+		g->regparse++;
+		br = regbranch(g, &flags);
+		if (br == NULL)
+			return(NULL);
+		regtail(g, ret, br);	/* BRANCH -> BRANCH. */
+		if (!(flags&HASWIDTH))
+			*flagp &= ~HASWIDTH;
+		*flagp |= flags&SPSTART;
+	}
+
+	/* Make a closing node, and hook it on the end. */
+	ender = regnode(g, (paren) ? CLOSE+parno : END);	
+	regtail(g, ret, ender);
+
+	/* Hook the tails of the branches to the closing node. */
+	for (br = ret; br != NULL; br = regnext(g, br))
+		regoptail(g, br, ender);
+
+	/* Check for proper termination. */
+	if (paren && *g->regparse++ != ')') {
+		FAIL("unmatched ()");
+	} else if (!paren && *g->regparse != '\0') {
+		if (*g->regparse == ')') {
+			FAIL("unmatched ()");
+		} else
+			FAIL("junk on end");	/* "Can't happen". */
+		/* NOTREACHED */
+	}
+
+	return(ret);
+}
+
+/*
+ - regbranch - one alternative of an | operator
+ *
+ * Implements the concatenation operator.
+ */
+static char *
+regbranch(struct match_globals *g, int *flagp)
+{
+	register char *ret;
+	register char *chain;
+	register char *latest;
+	int flags;
+
+	*flagp = WORST;		/* Tentatively. */
+
+	ret = regnode(g, BRANCH);
+	chain = NULL;
+	while (*g->regparse != '\0' && *g->regparse != '|' && *g->regparse != ')') {
+		latest = regpiece(g, &flags);
+		if (latest == NULL)
+			return(NULL);
+		*flagp |= flags&HASWIDTH;
+		if (chain == NULL)	/* First piece. */
+			*flagp |= flags&SPSTART;
+		else
+			regtail(g, chain, latest);
+		chain = latest;
+	}
+	if (chain == NULL)	/* Loop ran zero times. */
+		(void) regnode(g, NOTHING);
+
+	return(ret);
+}
+
+/*
+ - regpiece - something followed by possible [*+?]
+ *
+ * Note that the branching code sequences used for ? and the general cases
+ * of * and + are somewhat optimized:  they use the same NOTHING node as
+ * both the endmarker for their branch list and the body of the last branch.
+ * It might seem that this node could be dispensed with entirely, but the
+ * endmarker role is not redundant.
+ */
+static char *
+regpiece(struct match_globals *g, int *flagp)
+{
+	register char *ret;
+	register char op;
+	register char *next;
+	int flags;
+
+	ret = regatom(g, &flags);
+	if (ret == NULL)
+		return(NULL);
+
+	op = *g->regparse;
+	if (!ISMULT(op)) {
+		*flagp = flags;
+		return(ret);
+	}
+
+	if (!(flags&HASWIDTH) && op != '?')
+		FAIL("*+ operand could be empty");
+	*flagp = (op != '+') ? (WORST|SPSTART) : (WORST|HASWIDTH);
+
+	if (op == '*' && (flags&SIMPLE))
+		reginsert(g, STAR, ret);
+	else if (op == '*') {
+		/* Emit x* as (x&|), where & means "self". */
+		reginsert(g, BRANCH, ret);			/* Either x */
+		regoptail(g, ret, regnode(g, BACK));		/* and loop */
+		regoptail(g, ret, ret);			/* back */
+		regtail(g, ret, regnode(g, BRANCH));		/* or */
+		regtail(g, ret, regnode(g, NOTHING));		/* null. */
+	} else if (op == '+' && (flags&SIMPLE))
+		reginsert(g, PLUS, ret);
+	else if (op == '+') {
+		/* Emit x+ as x(&|), where & means "self". */
+		next = regnode(g, BRANCH);			/* Either */
+		regtail(g, ret, next);
+		regtail(g, regnode(g, BACK), ret);		/* loop back */
+		regtail(g, next, regnode(g, BRANCH));		/* or */
+		regtail(g, ret, regnode(g, NOTHING));		/* null. */
+	} else if (op == '?') {
+		/* Emit x? as (x|) */
+		reginsert(g, BRANCH, ret);			/* Either x */
+		regtail(g, ret, regnode(g, BRANCH));		/* or */
+		next = regnode(g, NOTHING);		/* null. */
+		regtail(g, ret, next);
+		regoptail(g, ret, next);
+	}
+	g->regparse++;
+	if (ISMULT(*g->regparse))
+		FAIL("nested *?+");
+
+	return(ret);
+}
+
+/*
+ - regatom - the lowest level
+ *
+ * Optimization:  gobbles an entire sequence of ordinary characters so that
+ * it can turn them into a single node, which is smaller to store and
+ * faster to run.  Backslashed characters are exceptions, each becoming a
+ * separate node; the code is simpler that way and it's not worth fixing.
+ */
+static char *
+regatom(struct match_globals *g, int *flagp)
+{
+	register char *ret;
+	int flags;
+
+	*flagp = WORST;		/* Tentatively. */
+
+	switch (*g->regparse++) {
+	case '^':
+		ret = regnode(g, BOL);
+		break;
+	case '$':
+		ret = regnode(g, EOL);
+		break;
+	case '.':
+		ret = regnode(g, ANY);
+		*flagp |= HASWIDTH|SIMPLE;
+		break;
+	case '[': {
+			register int class;
+			register int classend;
+
+			if (*g->regparse == '^') {	/* Complement of range. */
+				ret = regnode(g, ANYBUT);
+				g->regparse++;
+			} else
+				ret = regnode(g, ANYOF);
+			if (*g->regparse == ']' || *g->regparse == '-')
+				regc(g, *g->regparse++);
+			while (*g->regparse != '\0' && *g->regparse != ']') {
+				if (*g->regparse == '-') {
+					g->regparse++;
+					if (*g->regparse == ']' || *g->regparse == '\0')
+						regc(g, '-');
+					else {
+						class = UCHARAT(g->regparse-2)+1;
+						classend = UCHARAT(g->regparse);
+						if (class > classend+1)
+							FAIL("invalid [] range");
+						for (; class <= classend; class++)
+							regc(g, class);
+						g->regparse++;
+					}
+				} else
+					regc(g, *g->regparse++);
+			}
+			regc(g, '\0');
+			if (*g->regparse != ']')
+				FAIL("unmatched []");
+			g->regparse++;
+			*flagp |= HASWIDTH|SIMPLE;
+		}
+		break;
+	case '(':
+		ret = reg(g, 1, &flags);
+		if (ret == NULL)
+			return(NULL);
+		*flagp |= flags&(HASWIDTH|SPSTART);
+		break;
+	case '\0':
+	case '|':
+	case ')':
+		FAIL("internal urp");	/* Supposed to be caught earlier. */
+		break;
+	case '?':
+	case '+':
+	case '*':
+		FAIL("?+* follows nothing");
+		break;
+	case '\\':
+		if (*g->regparse == '\0')
+			FAIL("trailing \\");
+		ret = regnode(g, EXACTLY);
+		regc(g, *g->regparse++);
+		regc(g, '\0');
+		*flagp |= HASWIDTH|SIMPLE;
+		break;
+	default: {
+			register int len;
+			register char ender;
+
+			g->regparse--;
+			len = my_strcspn((const char *)g->regparse, (const char *)META);
+			if (len <= 0)
+				FAIL("internal disaster");
+			ender = *(g->regparse+len);
+			if (len > 1 && ISMULT(ender))
+				len--;		/* Back off clear of ?+* operand. */
+			*flagp |= HASWIDTH;
+			if (len == 1)
+				*flagp |= SIMPLE;
+			ret = regnode(g, EXACTLY);
+			while (len > 0) {
+				regc(g, *g->regparse++);
+				len--;
+			}
+			regc(g, '\0');
+		}
+		break;
+	}
+
+	return(ret);
+}
+
+/*
+ - regnode - emit a node
+ */
+static char *			/* Location. */
+regnode(struct match_globals *g, char op)
+{
+	register char *ret;
+	register char *ptr;
+
+	ret = g->regcode;
+	if (ret == &g->regdummy) {
+		g->regsize += 3;
+		return(ret);
+	}
+
+	ptr = ret;
+	*ptr++ = op;
+	*ptr++ = '\0';		/* Null "next" pointer. */
+	*ptr++ = '\0';
+	g->regcode = ptr;
+
+	return(ret);
+}
+
+/*
+ - regc - emit (if appropriate) a byte of code
+ */
+static void
+regc(struct match_globals *g, char b)
+{
+	if (g->regcode != &g->regdummy)
+		*g->regcode++ = b;
+	else
+		g->regsize++;
+}
+
+/*
+ - reginsert - insert an operator in front of already-emitted operand
+ *
+ * Means relocating the operand.
+ */
+static void
+reginsert(struct match_globals *g, char op, char* opnd)
+{
+	register char *src;
+	register char *dst;
+	register char *place;
+
+	if (g->regcode == &g->regdummy) {
+		g->regsize += 3;
+		return;
+	}
+
+	src = g->regcode;
+	g->regcode += 3;
+	dst = g->regcode;
+	while (src > opnd)
+		*--dst = *--src;
+
+	place = opnd;		/* Op node, where operand used to be. */
+	*place++ = op;
+	*place++ = '\0';
+	*place++ = '\0';
+}
+
+/*
+ - regtail - set the next-pointer at the end of a node chain
+ */
+static void
+regtail(struct match_globals *g, char *p, char *val)
+{
+	register char *scan;
+	register char *temp;
+	register int offset;
+
+	if (p == &g->regdummy)
+		return;
+
+	/* Find last node. */
+	scan = p;
+	for (;;) {
+		temp = regnext(g, scan);
+		if (temp == NULL)
+			break;
+		scan = temp;
+	}
+
+	if (OP(scan) == BACK)
+		offset = scan - val;
+	else
+		offset = val - scan;
+	*(scan+1) = (offset>>8)&0377;
+	*(scan+2) = offset&0377;
+}
+
+/*
+ - regoptail - regtail on operand of first argument; nop if operandless
+ */
+static void
+regoptail(struct match_globals *g, char *p, char *val)
+{
+	/* "Operandless" and "op != BRANCH" are synonymous in practice. */
+	if (p == NULL || p == &g->regdummy || OP(p) != BRANCH)
+		return;
+	regtail(g, OPERAND(p), val);
+}
+
+/*
+ * regexec and friends
+ */
+
+
+/*
+ * Forwards.
+ */
+STATIC int regtry(struct match_globals *g, regexp *prog, char *string);
+STATIC int regmatch(struct match_globals *g, char *prog);
+STATIC int regrepeat(struct match_globals *g, char *p);
+
+#ifdef DEBUG
+int regnarrate = 0;
+void regdump();
+STATIC char *regprop(char *op);
+#endif
+
+/*
+ - regexec - match a regexp against a string
+ */
+int
+regexec(regexp *prog, char *string)
+{
+	register char *s;
+	struct match_globals g;
+
+	/* Be paranoid... */
+	if (prog == NULL || string == NULL) {
+		printk("<3>Regexp: NULL parameter\n");
+		return(0);
+	}
+
+	/* Check validity of program. */
+	if (UCHARAT(prog->program) != MAGIC) {
+		printk("<3>Regexp: corrupted program\n");
+		return(0);
+	}
+
+	/* If there is a "must appear" string, look for it. */
+	if (prog->regmust != NULL) {
+		s = string;
+		while ((s = strchr(s, prog->regmust[0])) != NULL) {
+			if (strncmp(s, prog->regmust, prog->regmlen) == 0)
+				break;	/* Found it. */
+			s++;
+		}
+		if (s == NULL)	/* Not present. */
+			return(0);
+	}
+
+	/* Mark beginning of line for ^ . */
+	g.regbol = string;
+
+	/* Simplest case:  anchored match need be tried only once. */
+	if (prog->reganch)
+		return(regtry(&g, prog, string));
+
+	/* Messy cases:  unanchored match. */
+	s = string;
+	if (prog->regstart != '\0')
+		/* We know what char it must start with. */
+		while ((s = strchr(s, prog->regstart)) != NULL) {
+			if (regtry(&g, prog, s))
+				return(1);
+			s++;
+		}
+	else
+		/* We don't -- general case. */
+		do {
+			if (regtry(&g, prog, s))
+				return(1);
+		} while (*s++ != '\0');
+
+	/* Failure. */
+	return(0);
+}
+
+/*
+ - regtry - try match at specific point
+ */
+static int			/* 0 failure, 1 success */
+regtry(struct match_globals *g, regexp *prog, char *string)
+{
+	register int i;
+	register char **sp;
+	register char **ep;
+
+	g->reginput = string;
+	g->regstartp = prog->startp;
+	g->regendp = prog->endp;
+
+	sp = prog->startp;
+	ep = prog->endp;
+	for (i = NSUBEXP; i > 0; i--) {
+		*sp++ = NULL;
+		*ep++ = NULL;
+	}
+	if (regmatch(g, prog->program + 1)) {
+		prog->startp[0] = string;
+		prog->endp[0] = g->reginput;
+		return(1);
+	} else
+		return(0);
+}
+
+/*
+ - regmatch - main matching routine
+ *
+ * Conceptually the strategy is simple:  check to see whether the current
+ * node matches, call self recursively to see whether the rest matches,
+ * and then act accordingly.  In practice we make some effort to avoid
+ * recursion, in particular by going through "ordinary" nodes (that don't
+ * need to know whether the rest of the match failed) by a loop instead of
+ * by recursion.
+ */
+static int			/* 0 failure, 1 success */
+regmatch(struct match_globals *g, char *prog)
+{
+	register char *scan = prog; /* Current node. */
+	char *next;		    /* Next node. */
+
+#ifdef DEBUG
+	if (scan != NULL && regnarrate)
+		fprintf(stderr, "%s(\n", regprop(scan));
+#endif
+	while (scan != NULL) {
+#ifdef DEBUG
+		if (regnarrate)
+			fprintf(stderr, "%s...\n", regprop(scan));
+#endif
+		next = regnext(g, scan);
+
+		switch (OP(scan)) {
+		case BOL:
+			if (g->reginput != g->regbol)
+				return(0);
+			break;
+		case EOL:
+			if (*g->reginput != '\0')
+				return(0);
+			break;
+		case ANY:
+			if (*g->reginput == '\0')
+				return(0);
+			g->reginput++;
+			break;
+		case EXACTLY: {
+				register int len;
+				register char *opnd;
+
+				opnd = OPERAND(scan);
+				/* Inline the first character, for speed. */
+				if (*opnd != *g->reginput)
+					return(0);
+				len = strlen(opnd);
+				if (len > 1 && strncmp(opnd, g->reginput, len) != 0)
+					return(0);
+				g->reginput += len;
+			}
+			break;
+		case ANYOF:
+			if (*g->reginput == '\0' || strchr(OPERAND(scan), *g->reginput) == NULL)
+				return(0);
+			g->reginput++;
+			break;
+		case ANYBUT:
+			if (*g->reginput == '\0' || strchr(OPERAND(scan), *g->reginput) != NULL)
+				return(0);
+			g->reginput++;
+			break;
+		case NOTHING:
+		case BACK:
+			break;
+		case OPEN+1:
+		case OPEN+2:
+		case OPEN+3:
+		case OPEN+4:
+		case OPEN+5:
+		case OPEN+6:
+		case OPEN+7:
+		case OPEN+8:
+		case OPEN+9: {
+				register int no;
+				register char *save;
+
+				no = OP(scan) - OPEN;
+				save = g->reginput;
+
+				if (regmatch(g, next)) {
+					/*
+					 * Don't set startp if some later
+					 * invocation of the same parentheses
+					 * already has.
+					 */
+					if (g->regstartp[no] == NULL)
+						g->regstartp[no] = save;
+					return(1);
+				} else
+					return(0);
+			}
+			break;
+		case CLOSE+1:
+		case CLOSE+2:
+		case CLOSE+3:
+		case CLOSE+4:
+		case CLOSE+5:
+		case CLOSE+6:
+		case CLOSE+7:
+		case CLOSE+8:
+		case CLOSE+9:
+			{
+				register int no;
+				register char *save;
+
+				no = OP(scan) - CLOSE;
+				save = g->reginput;
+
+				if (regmatch(g, next)) {
+					/*
+					 * Don't set endp if some later
+					 * invocation of the same parentheses
+					 * already has.
+					 */
+					if (g->regendp[no] == NULL)
+						g->regendp[no] = save;
+					return(1);
+				} else
+					return(0);
+			}
+			break;
+		case BRANCH: {
+				register char *save;
+
+				if (OP(next) != BRANCH)		/* No choice. */
+					next = OPERAND(scan);	/* Avoid recursion. */
+				else {
+					do {
+						save = g->reginput;
+						if (regmatch(g, OPERAND(scan)))
+							return(1);
+						g->reginput = save;
+						scan = regnext(g, scan);
+					} while (scan != NULL && OP(scan) == BRANCH);
+					return(0);
+					/* NOTREACHED */
+				}
+			}
+			break;
+		case STAR:
+		case PLUS: {
+				register char nextch;
+				register int no;
+				register char *save;
+				register int min;
+
+				/*
+				 * Lookahead to avoid useless match attempts
+				 * when we know what character comes next.
+				 */
+				nextch = '\0';
+				if (OP(next) == EXACTLY)
+					nextch = *OPERAND(next);
+				min = (OP(scan) == STAR) ? 0 : 1;
+				save = g->reginput;
+				no = regrepeat(g, OPERAND(scan));
+				while (no >= min) {
+					/* If it could work, try it. */
+					if (nextch == '\0' || *g->reginput == nextch)
+						if (regmatch(g, next))
+							return(1);
+					/* Couldn't or didn't -- back up. */
+					no--;
+					g->reginput = save + no;
+				}
+				return(0);
+			}
+			break;
+		case END:
+			return(1);	/* Success! */
+			break;
+		default:
+			printk("<3>Regexp: memory corruption\n");
+			return(0);
+			break;
+		}
+
+		scan = next;
+	}
+
+	/*
+	 * We get here only if there's trouble -- normally "case END" is
+	 * the terminating point.
+	 */
+	printk("<3>Regexp: corrupted pointers\n");
+	return(0);
+}
+
+/*
+ - regrepeat - repeatedly match something simple, report how many
+ */
+static int
+regrepeat(struct match_globals *g, char *p)
+{
+	register int count = 0;
+	register char *scan;
+	register char *opnd;
+
+	scan = g->reginput;
+	opnd = OPERAND(p);
+	switch (OP(p)) {
+	case ANY:
+		count = strlen(scan);
+		scan += count;
+		break;
+	case EXACTLY:
+		while (*opnd == *scan) {
+			count++;
+			scan++;
+		}
+		break;
+	case ANYOF:
+		while (*scan != '\0' && strchr(opnd, *scan) != NULL) {
+			count++;
+			scan++;
+		}
+		break;
+	case ANYBUT:
+		while (*scan != '\0' && strchr(opnd, *scan) == NULL) {
+			count++;
+			scan++;
+		}
+		break;
+	default:		/* Oh dear.  Called inappropriately. */
+		printk("<3>Regexp: internal foulup\n");
+		count = 0;	/* Best compromise. */
+		break;
+	}
+	g->reginput = scan;
+
+	return(count);
+}
+
+/*
+ - regnext - dig the "next" pointer out of a node
+ */
+static char*
+regnext(struct match_globals *g, char *p)
+{
+	register int offset;
+
+	if (p == &g->regdummy)
+		return(NULL);
+
+	offset = NEXT(p);
+	if (offset == 0)
+		return(NULL);
+
+	if (OP(p) == BACK)
+		return(p-offset);
+	else
+		return(p+offset);
+}
+
+#ifdef DEBUG
+
+STATIC char *regprop();
+
+/*
+ - regdump - dump a regexp onto stdout in vaguely comprehensible form
+ */
+void
+regdump(regexp *r)
+{
+	register char *s;
+	register char op = EXACTLY;	/* Arbitrary non-END op. */
+	register char *next;
+	/* extern char *strchr(); */
+
+
+	s = r->program + 1;
+	while (op != END) {	/* While that wasn't END last time... */
+		op = OP(s);
+		printf("%2d%s", s-r->program, regprop(s));	/* Where, what. */
+		next = regnext(s);
+		if (next == NULL)		/* Next ptr. */
+			printf("(0)");
+		else
+			printf("(%d)", (s-r->program)+(next-s));
+		s += 3;
+		if (op == ANYOF || op == ANYBUT || op == EXACTLY) {
+			/* Literal string, where present. */
+			while (*s != '\0') {
+				putchar(*s);
+				s++;
+			}
+			s++;
+		}
+		putchar('\n');
+	}
+
+	/* Header fields of interest. */
+	if (r->regstart != '\0')
+		printf("start `%c' ", r->regstart);
+	if (r->reganch)
+		printf("anchored ");
+	if (r->regmust != NULL)
+		printf("must have \"%s\"", r->regmust);
+	printf("\n");
+}
+
+/*
+ - regprop - printable representation of opcode
+ */
+static char *
+regprop(char *op)
+{
+#define BUFLEN 50
+	register char *p;
+	static char buf[BUFLEN];
+
+	strcpy(buf, ":");
+
+	switch (OP(op)) {
+	case BOL:
+		p = "BOL";
+		break;
+	case EOL:
+		p = "EOL";
+		break;
+	case ANY:
+		p = "ANY";
+		break;
+	case ANYOF:
+		p = "ANYOF";
+		break;
+	case ANYBUT:
+		p = "ANYBUT";
+		break;
+	case BRANCH:
+		p = "BRANCH";
+		break;
+	case EXACTLY:
+		p = "EXACTLY";
+		break;
+	case NOTHING:
+		p = "NOTHING";
+		break;
+	case BACK:
+		p = "BACK";
+		break;
+	case END:
+		p = "END";
+		break;
+	case OPEN+1:
+	case OPEN+2:
+	case OPEN+3:
+	case OPEN+4:
+	case OPEN+5:
+	case OPEN+6:
+	case OPEN+7:
+	case OPEN+8:
+	case OPEN+9:
+		snprintf(buf+strlen(buf),BUFLEN-strlen(buf), "OPEN%d", OP(op)-OPEN);
+		p = NULL;
+		break;
+	case CLOSE+1:
+	case CLOSE+2:
+	case CLOSE+3:
+	case CLOSE+4:
+	case CLOSE+5:
+	case CLOSE+6:
+	case CLOSE+7:
+	case CLOSE+8:
+	case CLOSE+9:
+		snprintf(buf+strlen(buf),BUFLEN-strlen(buf), "CLOSE%d", OP(op)-CLOSE);
+		p = NULL;
+		break;
+	case STAR:
+		p = "STAR";
+		break;
+	case PLUS:
+		p = "PLUS";
+		break;
+	default:
+		printk("<3>Regexp: corrupted opcode\n");
+		break;
+	}
+	if (p != NULL)
+		strncat(buf, p, BUFLEN-strlen(buf));
+	return(buf);
+}
+#endif
+
+
diff -urNp -x '*.orig' linux-5.11/net/netfilter/regexp/regexp.h linux-5.11/net/netfilter/regexp/regexp.h
--- linux-5.11/net/netfilter/regexp/regexp.h	1970-01-01 01:00:00.000000000 +0100
+++ linux-5.11/net/netfilter/regexp/regexp.h	2021-02-24 13:21:48.335107407 +0100
@@ -0,0 +1,41 @@
+/*
+ * Definitions etc. for regexp(3) routines.
+ *
+ * Caveat:  this is V8 regexp(3) [actually, a reimplementation thereof],
+ * not the System V one.
+ */
+
+#ifndef REGEXP_H
+#define REGEXP_H
+
+
+/*
+http://www.opensource.apple.com/darwinsource/10.3/expect-1/expect/expect.h ,
+which contains a version of this library, says:
+
+ *
+ * NSUBEXP must be at least 10, and no greater than 117 or the parser
+ * will not work properly.
+ *
+
+However, it looks rather like this library is limited to 10.  If you think
+otherwise, let us know.
+*/
+
+#define NSUBEXP  10
+typedef struct regexp {
+	char *startp[NSUBEXP];
+	char *endp[NSUBEXP];
+	char regstart;		/* Internal use only. */
+	char reganch;		/* Internal use only. */
+	char *regmust;		/* Internal use only. */
+	int regmlen;		/* Internal use only. */
+	char program[1];	/* Unwarranted chumminess with compiler. */
+} regexp;
+
+regexp * regcomp(char *exp, int *patternsize);
+int regexec(regexp *prog, char *string);
+void regsub(regexp *prog, char *source, char *dest);
+void regerror(char *s);
+
+#endif
diff -urNp -x '*.orig' linux-5.11/net/netfilter/regexp/regmagic.h linux-5.11/net/netfilter/regexp/regmagic.h
--- linux-5.11/net/netfilter/regexp/regmagic.h	1970-01-01 01:00:00.000000000 +0100
+++ linux-5.11/net/netfilter/regexp/regmagic.h	2021-02-24 13:21:48.335107407 +0100
@@ -0,0 +1,5 @@
+/*
+ * The first byte of the regexp internal "program" is actually this magic
+ * number; the start node begins in the second byte.
+ */
+#define	MAGIC	0234
diff -urNp -x '*.orig' linux-5.11/net/netfilter/regexp/regsub.c linux-5.11/net/netfilter/regexp/regsub.c
--- linux-5.11/net/netfilter/regexp/regsub.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-5.11/net/netfilter/regexp/regsub.c	2021-02-24 13:21:48.335107407 +0100
@@ -0,0 +1,95 @@
+/*
+ * regsub
+ * @(#)regsub.c	1.3 of 2 April 86
+ *
+ *	Copyright (c) 1986 by University of Toronto.
+ *	Written by Henry Spencer.  Not derived from licensed software.
+ *
+ *	Permission is granted to anyone to use this software for any
+ *	purpose on any computer system, and to redistribute it freely,
+ *	subject to the following restrictions:
+ *
+ *	1. The author is not responsible for the consequences of use of
+ *		this software, no matter how awful, even if they arise
+ *		from defects in it.
+ *
+ *	2. The origin of this software must not be misrepresented, either
+ *		by explicit claim or by omission.
+ *
+ *	3. Altered versions must be plainly marked as such, and must not
+ *		be misrepresented as being the original software.
+ *
+ *
+ * This code was modified by Ethan Sommer to work within the kernel
+ * (it now uses kmalloc etc..)
+ *
+ */
+#include "regexp.h"
+#include "regmagic.h"
+#include <linux/string.h>
+
+
+#ifndef CHARBITS
+#define	UCHARAT(p)	((int)*(unsigned char *)(p))
+#else
+#define	UCHARAT(p)	((int)*(p)&CHARBITS)
+#endif
+
+#if 0
+//void regerror(char * s)
+//{
+//        printk("regexp(3): %s", s);
+//        /* NOTREACHED */
+//}
+#endif
+
+/*
+ - regsub - perform substitutions after a regexp match
+ */
+void
+regsub(regexp * prog, char * source, char * dest)
+{
+	register char *src;
+	register char *dst;
+	register char c;
+	register int no;
+	register int len;
+	
+	/* Not necessary and gcc doesn't like it -MLS */
+	/*extern char *strncpy();*/
+
+	if (prog == NULL || source == NULL || dest == NULL) {
+		regerror("NULL parm to regsub");
+		return;
+	}
+	if (UCHARAT(prog->program) != MAGIC) {
+		regerror("damaged regexp fed to regsub");
+		return;
+	}
+
+	src = source;
+	dst = dest;
+	while ((c = *src++) != '\0') {
+		if (c == '&')
+			no = 0;
+		else if (c == '\\' && '0' <= *src && *src <= '9')
+			no = *src++ - '0';
+		else
+			no = -1;
+
+		if (no < 0) {	/* Ordinary character. */
+			if (c == '\\' && (*src == '\\' || *src == '&'))
+				c = *src++;
+			*dst++ = c;
+		} else if (prog->startp[no] != NULL && prog->endp[no] != NULL) {
+			len = prog->endp[no] - prog->startp[no];
+			(void) strncpy(dst, prog->startp[no], len);
+			dst += len;
+			if (len != 0 && *(dst-1) == '\0') {	/* strncpy hit NUL. */
+				regerror("damaged match string");
+				return;
+			}
+		}
+	}
+	*dst++ = '\0';
+}
diff -urNp -x '*.orig' linux-5.11/net/netfilter/xt_layer7.c linux-5.11/net/netfilter/xt_layer7.c
--- linux-5.11/net/netfilter/xt_layer7.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-5.11/net/netfilter/xt_layer7.c	2021-02-24 13:21:48.335107407 +0100
@@ -0,0 +1,656 @@
+/*
+  Kernel module to match application layer (OSI layer 7) data in connections.
+
+  http://l7-filter.sf.net
+
+  (C) 2003-2009 Matthew Strait and Ethan Sommer.
+
+  This program is free software; you can redistribute it and/or
+  modify it under the terms of the GNU General Public License
+  as published by the Free Software Foundation; either version
+  2 of the License, or (at your option) any later version.
+  http://www.gnu.org/licenses/gpl.txt
+
+  Based on ipt_string.c (C) 2000 Emmanuel Roger <winfield@freegates.be>,
+  xt_helper.c (C) 2002 Harald Welte and cls_layer7.c (C) 2003 Matthew Strait,
+  Ethan Sommer, Justin Levandoski.
+*/
+
+#include <linux/spinlock.h>
+#include <linux/version.h>
+#include <net/ip.h>
+#include <net/tcp.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/netfilter.h>
+#include <net/netfilter/nf_conntrack.h>
+#include <net/netfilter/nf_conntrack_core.h>
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 27)
+#include <net/netfilter/nf_conntrack_extend.h>
+#include <net/netfilter/nf_conntrack_acct.h>
+#endif
+#include <linux/netfilter/x_tables.h>
+#include <linux/netfilter/xt_layer7.h>
+#include <linux/ctype.h>
+#include <linux/proc_fs.h>
+
+#include "regexp/regexp.c"
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Matthew Strait <quadong@users.sf.net>, Ethan Sommer <sommere@users.sf.net>");
+MODULE_DESCRIPTION("iptables application layer match module");
+MODULE_ALIAS("ipt_layer7");
+MODULE_VERSION("2.21");
+
+static int maxdatalen = 2048; // this is the default
+module_param(maxdatalen, int, 0444);
+MODULE_PARM_DESC(maxdatalen, "maximum bytes of data looked at by l7-filter");
+#ifdef CONFIG_NETFILTER_XT_MATCH_LAYER7_DEBUG
+	#define DPRINTK(format,args...) printk(format,##args)
+#else
+	#define DPRINTK(format,args...)
+#endif
+
+/* Number of packets whose data we look at.
+This can be modified through /proc/net/layer7_numpackets */
+static int num_packets = 10;
+
+static struct pattern_cache {
+	char * regex_string;
+	regexp * pattern;
+	struct pattern_cache * next;
+} * first_pattern_cache = NULL;
+
+DEFINE_SPINLOCK(l7_lock);
+
+static int total_acct_packets(struct nf_conn *ct)
+{
+#if LINUX_VERSION_CODE <= KERNEL_VERSION(2, 6, 26)
+	BUG_ON(ct == NULL);
+	return (ct->counters[IP_CT_DIR_ORIGINAL].packets + ct->counters[IP_CT_DIR_REPLY].packets);
+#else
+	struct nf_conn_counter *acct;
+
+	BUG_ON(ct == NULL);
+	acct = nf_conn_acct_find(ct);
+	if (!acct)
+		return 0;
+	return (atomic64_read(&acct[IP_CT_DIR_ORIGINAL].packets) + atomic64_read(&acct[IP_CT_DIR_REPLY].packets));
+#endif
+}
+
+#ifdef CONFIG_IP_NF_MATCH_LAYER7_DEBUG
+/* Converts an unfriendly string into a friendly one by
+replacing unprintables with periods and all whitespace with " ". */
+static char * friendly_print(unsigned char * s)
+{
+	char * f = kmalloc(strlen(s) + 1, GFP_ATOMIC);
+	int i;
+
+	if(!f) {
+		if (net_ratelimit())
+			printk(KERN_ERR "layer7: out of memory in "
+					"friendly_print, bailing.\n");
+		return NULL;
+	}
+
+	for(i = 0; i < strlen(s); i++){
+		if(isprint(s[i]) && s[i] < 128)	f[i] = s[i];
+		else if(isspace(s[i]))		f[i] = ' ';
+		else 				f[i] = '.';
+	}
+	f[i] = '\0';
+	return f;
+}
+
+static char dec2hex(int i)
+{
+	switch (i) {
+		case 0 ... 9:
+			return (i + '0');
+			break;
+		case 10 ... 15:
+			return (i - 10 + 'a');
+			break;
+		default:
+			if (net_ratelimit())
+				printk("layer7: Problem in dec2hex\n");
+			return '\0';
+	}
+}
+
+static char * hex_print(unsigned char * s)
+{
+	char * g = kmalloc(strlen(s)*3 + 1, GFP_ATOMIC);
+	int i;
+
+	if(!g) {
+	       if (net_ratelimit())
+			printk(KERN_ERR "layer7: out of memory in hex_print, "
+					"bailing.\n");
+	       return NULL;
+	}
+
+	for(i = 0; i < strlen(s); i++) {
+		g[i*3    ] = dec2hex(s[i]/16);
+		g[i*3 + 1] = dec2hex(s[i]%16);
+		g[i*3 + 2] = ' ';
+	}
+	g[i*3] = '\0';
+
+	return g;
+}
+#endif // DEBUG
+
+/* Use instead of regcomp.  As we expect to be seeing the same regexps over and
+over again, it make sense to cache the results. */
+static regexp * compile_and_cache(const char * regex_string, 
+                                  const char * protocol)
+{
+	struct pattern_cache * node               = first_pattern_cache;
+	struct pattern_cache * last_pattern_cache = first_pattern_cache;
+	struct pattern_cache * tmp;
+	unsigned int len;
+
+	while (node != NULL) {
+		if (!strcmp(node->regex_string, regex_string))
+		return node->pattern;
+
+		last_pattern_cache = node;/* points at the last non-NULL node */
+		node = node->next;
+	}
+
+	/* If we reach the end of the list, then we have not yet cached
+	   the pattern for this regex. Let's do that now.
+	   Be paranoid about running out of memory to avoid list corruption. */
+	tmp = kmalloc(sizeof(struct pattern_cache), GFP_ATOMIC);
+
+	if(!tmp) {
+		if (net_ratelimit())
+			printk(KERN_ERR "layer7: out of memory in "
+					"compile_and_cache, bailing.\n");
+		return NULL;
+	}
+
+	tmp->regex_string  = kmalloc(strlen(regex_string) + 1, GFP_ATOMIC);
+	tmp->pattern       = kmalloc(sizeof(struct regexp),    GFP_ATOMIC);
+	tmp->next = NULL;
+
+	if(!tmp->regex_string || !tmp->pattern) {
+		if (net_ratelimit())
+			printk(KERN_ERR "layer7: out of memory in "
+					"compile_and_cache, bailing.\n");
+		kfree(tmp->regex_string);
+		kfree(tmp->pattern);
+		kfree(tmp);
+		return NULL;
+	}
+
+	/* Ok.  The new node is all ready now. */
+	node = tmp;
+
+	if(first_pattern_cache == NULL) /* list is empty */
+		first_pattern_cache = node; /* make node the beginning */
+	else
+		last_pattern_cache->next = node; /* attach node to the end */
+
+	/* copy the string and compile the regex */
+	len = strlen(regex_string);
+	DPRINTK("About to compile this: \"%s\"\n", regex_string);
+	node->pattern = regcomp((char *)regex_string, &len);
+	if ( !node->pattern ) {
+		if (net_ratelimit())
+			printk(KERN_ERR "layer7: Error compiling regexp "
+					"\"%s\" (%s)\n", 
+					regex_string, protocol);
+		/* pattern is now cached as NULL, so we won't try again. */
+	}
+
+	strcpy(node->regex_string, regex_string);
+	return node->pattern;
+}
+
+static int can_handle(const struct sk_buff *skb)
+{
+	if(!ip_hdr(skb)) /* not IP */
+		return 0;
+	if(ip_hdr(skb)->protocol != IPPROTO_TCP &&
+	   ip_hdr(skb)->protocol != IPPROTO_UDP &&
+	   ip_hdr(skb)->protocol != IPPROTO_ICMP)
+		return 0;
+	return 1;
+}
+
+/* Returns offset the into the skb->data that the application data starts */
+static int app_data_offset(const struct sk_buff *skb)
+{
+	/* In case we are ported somewhere (ebtables?) where ip_hdr(skb)
+	isn't set, this can be gotten from 4*(skb->data[0] & 0x0f) as well. */
+	int ip_hl = 4*ip_hdr(skb)->ihl;
+
+	if( ip_hdr(skb)->protocol == IPPROTO_TCP ) {
+		/* 12 == offset into TCP header for the header length field.
+		Can't get this with skb->h.th->doff because the tcphdr
+		struct doesn't get set when routing (this is confirmed to be
+		true in Netfilter as well as QoS.) */
+		int tcp_hl = 4*(skb->data[ip_hl + 12] >> 4);
+
+		return ip_hl + tcp_hl;
+	} else if( ip_hdr(skb)->protocol == IPPROTO_UDP  ) {
+		return ip_hl + 8; /* UDP header is always 8 bytes */
+	} else if( ip_hdr(skb)->protocol == IPPROTO_ICMP ) {
+		return ip_hl + 8; /* ICMP header is 8 bytes */
+	} else {
+		if (net_ratelimit())
+			printk(KERN_ERR "layer7: tried to handle unknown "
+					"protocol!\n");
+		return ip_hl + 8; /* something reasonable */
+	}
+}
+
+/* handles whether there's a match when we aren't appending data anymore */
+static int match_no_append(struct nf_conn * conntrack, 
+                           struct nf_conn * master_conntrack, 
+                           enum ip_conntrack_info ctinfo,
+                           enum ip_conntrack_info master_ctinfo,
+                           const struct xt_layer7_info * info)
+{
+	/* If we're in here, throw the app data away */
+	if(master_conntrack->layer7.app_data != NULL) {
+
+	#ifdef CONFIG_IP_NF_MATCH_LAYER7_DEBUG
+		if(!master_conntrack->layer7.app_proto) {
+			char * f = 
+			  friendly_print(master_conntrack->layer7.app_data);
+			char * g = 
+			  hex_print(master_conntrack->layer7.app_data);
+			DPRINTK("\nl7-filter gave up after %d bytes "
+				"(%d packets):\n%s\n",
+				strlen(f), total_acct_packets(master_conntrack), f);
+			kfree(f);
+			DPRINTK("In hex: %s\n", g);
+			kfree(g);
+		}
+	#endif
+
+		kfree(master_conntrack->layer7.app_data);
+		master_conntrack->layer7.app_data = NULL; /* don't free again */
+	}
+
+	if(master_conntrack->layer7.app_proto){
+		/* Here child connections set their .app_proto (for /proc) */
+		if(!conntrack->layer7.app_proto) {
+			conntrack->layer7.app_proto = 
+			  kmalloc(strlen(master_conntrack->layer7.app_proto)+1, 
+			    GFP_ATOMIC);
+			if(!conntrack->layer7.app_proto){
+				if (net_ratelimit())
+					printk(KERN_ERR "layer7: out of memory "
+							"in match_no_append, "
+							"bailing.\n");
+				return 1;
+			}
+			strcpy(conntrack->layer7.app_proto, 
+				master_conntrack->layer7.app_proto);
+		}
+
+		return (!strcmp(master_conntrack->layer7.app_proto, 
+				info->protocol));
+	}
+	else {
+		/* If not classified, set to "unknown" to distinguish from
+		connections that are still being tested. */
+		master_conntrack->layer7.app_proto = 
+			kmalloc(strlen("unknown")+1, GFP_ATOMIC);
+		if(!master_conntrack->layer7.app_proto){
+			if (net_ratelimit())
+				printk(KERN_ERR "layer7: out of memory in "
+						"match_no_append, bailing.\n");
+			return 1;
+		}
+		strcpy(master_conntrack->layer7.app_proto, "unknown");
+		return 0;
+	}
+}
+
+/* add the new app data to the conntrack.  Return number of bytes added. */
+static int add_data(struct nf_conn * master_conntrack,
+                    char * app_data, int appdatalen)
+{
+	int length = 0, i;
+	int oldlength = master_conntrack->layer7.app_data_len;
+
+	/* This is a fix for a race condition by Deti Fliegl. However, I'm not 
+	   clear on whether the race condition exists or whether this really 
+	   fixes it.  I might just be being dense... Anyway, if it's not really 
+	   a fix, all it does is waste a very small amount of time. */
+	if(!master_conntrack->layer7.app_data) return 0;
+
+	/* Strip nulls. Make everything lower case (our regex lib doesn't
+	do case insensitivity).  Add it to the end of the current data. */
+	for(i = 0; i < maxdatalen-oldlength-1 &&
+		   i < appdatalen; i++) {
+		if(app_data[i] != '\0') {
+			/* the kernel version of tolower mungs 'upper ascii' */
+			master_conntrack->layer7.app_data[length+oldlength] =
+				isascii(app_data[i])? 
+					tolower(app_data[i]) : app_data[i];
+			length++;
+		}
+	}
+
+	master_conntrack->layer7.app_data[length+oldlength] = '\0';
+	master_conntrack->layer7.app_data_len = length + oldlength;
+
+	return length;
+}
+
+/* taken from drivers/video/modedb.c */
+static int my_atoi(const char *s)
+{
+	int val = 0;
+
+	for (;; s++) {
+		switch (*s) {
+			case '0'...'9':
+			val = 10*val+(*s-'0');
+			break;
+		default:
+			return val;
+		}
+	}
+}
+
+/* write out num_packets to userland. */
+static int layer7_read_proc(char* page, char ** start, off_t off, int count,
+                            int* eof, void * data)
+{
+	if(num_packets > 99 && net_ratelimit())
+		printk(KERN_ERR "layer7: NOT REACHED. num_packets too big\n");
+
+	page[0] = num_packets/10 + '0';
+	page[1] = num_packets%10 + '0';
+	page[2] = '\n';
+	page[3] = '\0';
+
+	*eof=1;
+
+	return 3;
+}
+
+/* Read in num_packets from userland */
+static int layer7_write_proc(struct file* file, const char* buffer,
+                             unsigned long count, void *data)
+{
+	char * foo = kmalloc(count, GFP_ATOMIC);
+
+	if(!foo){
+		if (net_ratelimit())
+			printk(KERN_ERR "layer7: out of memory, bailing. "
+					"num_packets unchanged.\n");
+		return count;
+	}
+
+	if(copy_from_user(foo, buffer, count)) {
+		return -EFAULT;
+	}
+
+
+	num_packets = my_atoi(foo);
+	kfree (foo);
+
+	/* This has an arbitrary limit to make the math easier. I'm lazy.
+	But anyway, 99 is a LOT! If you want more, you're doing it wrong! */
+	if(num_packets > 99) {
+		printk(KERN_WARNING "layer7: num_packets can't be > 99.\n");
+		num_packets = 99;
+	} else if(num_packets < 1) {
+		printk(KERN_WARNING "layer7: num_packets can't be < 1.\n");
+		num_packets = 1;
+	}
+
+	return count;
+}
+
+static bool
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 28)
+match(const struct sk_buff *skbin, struct xt_action_param *par)
+#else
+match(const struct sk_buff *skbin,
+      const struct net_device *in,
+      const struct net_device *out,
+      const struct xt_match *match,
+      const void *matchinfo,
+      int offset,
+      unsigned int protoff,
+      bool *hotdrop)
+#endif
+{
+	/* sidestep const without getting a compiler warning... */
+	struct sk_buff * skb = (struct sk_buff *)skbin; 
+
+	const struct xt_layer7_info * info = 
+	#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 28)
+		par->matchinfo;
+	#else
+		matchinfo;
+	#endif
+
+	enum ip_conntrack_info master_ctinfo, ctinfo;
+	struct nf_conn *master_conntrack, *conntrack;
+	unsigned char * app_data;
+	unsigned int pattern_result, appdatalen;
+	regexp * comppattern;
+
+	/* Be paranoid/incompetent - lock the entire match function. */
+	spin_lock_bh(&l7_lock);
+
+	if(!can_handle(skb)){
+		DPRINTK("layer7: This is some protocol I can't handle.\n");
+		spin_unlock_bh(&l7_lock);
+		return info->invert;
+	}
+
+	/* Treat parent & all its children together as one connection, except
+	for the purpose of setting conntrack->layer7.app_proto in the actual
+	connection. This makes /proc/net/ip_conntrack more satisfying. */
+	if(!(conntrack = nf_ct_get(skb, &ctinfo)) ||
+	   !(master_conntrack=nf_ct_get(skb,&master_ctinfo))){
+		DPRINTK("layer7: couldn't get conntrack.\n");
+		spin_unlock_bh(&l7_lock);
+		return info->invert;
+	}
+
+	/* Try to get a master conntrack (and its master etc) for FTP, etc. */
+	while (master_ct(master_conntrack) != NULL)
+		master_conntrack = master_ct(master_conntrack);
+
+	/* if we've classified it or seen too many packets */
+	if(total_acct_packets(master_conntrack) > num_packets ||
+	   master_conntrack->layer7.app_proto) {
+
+		pattern_result = match_no_append(conntrack, master_conntrack, 
+						 ctinfo, master_ctinfo, info);
+
+		/* skb->cb[0] == seen. Don't do things twice if there are 
+		multiple l7 rules. I'm not sure that using cb for this purpose 
+		is correct, even though it says "put your private variables 
+		there". But it doesn't look like it is being used for anything
+		else in the skbs that make it here. */
+		skb->cb[0] = 1; /* marking it seen here's probably irrelevant */
+
+		spin_unlock_bh(&l7_lock);
+		return (pattern_result ^ info->invert);
+	}
+
+	if(skb_is_nonlinear(skb)){
+		if(skb_linearize(skb) != 0){
+			if (net_ratelimit())
+				printk(KERN_ERR "layer7: failed to linearize "
+						"packet, bailing.\n");
+			spin_unlock_bh(&l7_lock);
+			return info->invert;
+		}
+	}
+
+	/* now that the skb is linearized, it's safe to set these. */
+	app_data = skb->data + app_data_offset(skb);
+	appdatalen = skb_tail_pointer(skb) - app_data;
+
+	/* the return value gets checked later, when we're ready to use it */
+	comppattern = compile_and_cache(info->pattern, info->protocol);
+
+	/* On the first packet of a connection, allocate space for app data */
+	if(total_acct_packets(master_conntrack) == 1 && !skb->cb[0] && 
+	   !master_conntrack->layer7.app_data){
+		master_conntrack->layer7.app_data = 
+			kmalloc(maxdatalen, GFP_ATOMIC);
+		if(!master_conntrack->layer7.app_data){
+			if (net_ratelimit())
+				printk(KERN_ERR "layer7: out of memory in "
+						"match, bailing.\n");
+			spin_unlock_bh(&l7_lock);
+			return info->invert;
+		}
+
+		master_conntrack->layer7.app_data[0] = '\0';
+	}
+
+	/* Can be here, but unallocated, if numpackets is increased near
+	the beginning of a connection */
+	if(master_conntrack->layer7.app_data == NULL){
+		spin_unlock_bh(&l7_lock);
+		return info->invert; /* unmatched */
+	}
+
+	if(!skb->cb[0]){
+		int newbytes;
+		newbytes = add_data(master_conntrack, app_data, appdatalen);
+
+		if(newbytes == 0) { /* didn't add any data */
+			skb->cb[0] = 1;
+			/* Didn't match before, not going to match now */
+			spin_unlock_bh(&l7_lock);
+			return info->invert;
+		}
+	}
+
+	/* If looking for "unknown", then never match.  "Unknown" means that
+	we've given up; we're still trying with these packets. */
+	if(!strcmp(info->protocol, "unknown")) {
+		pattern_result = 0;
+	/* If looking for "unset", then always match. "Unset" means that we
+	haven't yet classified the connection. */
+	} else if(!strcmp(info->protocol, "unset")) {
+		pattern_result = 2;
+		DPRINTK("layer7: matched unset: not yet classified "
+			"(%d/%d packets)\n",
+                        total_acct_packets(master_conntrack), num_packets);
+	/* If the regexp failed to compile, don't bother running it */
+	} else if(comppattern && 
+		  regexec(comppattern, master_conntrack->layer7.app_data)){
+		DPRINTK("layer7: matched %s\n", info->protocol);
+		pattern_result = 1;
+	} else pattern_result = 0;
+
+	if(pattern_result == 1) {
+		master_conntrack->layer7.app_proto = 
+			kmalloc(strlen(info->protocol)+1, GFP_ATOMIC);
+		if(!master_conntrack->layer7.app_proto){
+			if (net_ratelimit())
+				printk(KERN_ERR "layer7: out of memory in "
+						"match, bailing.\n");
+			spin_unlock_bh(&l7_lock);
+			return (pattern_result ^ info->invert);
+		}
+		strcpy(master_conntrack->layer7.app_proto, info->protocol);
+	} else if(pattern_result > 1) { /* cleanup from "unset" */
+		pattern_result = 1;
+	}
+
+	/* mark the packet seen */
+	skb->cb[0] = 1;
+
+	spin_unlock_bh(&l7_lock);
+	return (pattern_result ^ info->invert);
+}
+
+// load nf_conntrack_ipv4
+static int check(const struct xt_mtchk_param *par)
+{
+        if (nf_ct_l3proto_try_module_get(par->family) < 0) {
+                pr_info("can't load conntrack support for "
+                                    "proto=%d\n", par->family);
+                return -EINVAL;
+        }
+	return 0;
+}
+
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 28)
+	static void destroy(const struct xt_mtdtor_param *par)
+	{
+		nf_ct_l3proto_module_put(par->family);
+	}
+#else
+	static void destroy(const struct xt_match *match, void *matchinfo)
+	{
+		nf_ct_l3proto_module_put(match->family);
+	}
+#endif
+
+static struct xt_match xt_layer7_match[] __read_mostly = {
+{
+	.name		= "layer7",
+	.family		= AF_INET,
+	.checkentry	= check,
+	.match		= match,
+	.destroy	= destroy,
+	.matchsize	= sizeof(struct xt_layer7_info),
+	.me		= THIS_MODULE
+}
+};
+
+static void layer7_cleanup_proc(void)
+{
+	remove_proc_entry("layer7_numpackets", init_net.proc_net);
+}
+
+/* register the proc file */
+static void layer7_init_proc(void)
+{
+	struct proc_dir_entry* entry;
+	entry = create_proc_entry("layer7_numpackets", 0644, init_net.proc_net);
+	entry->read_proc = layer7_read_proc;
+	entry->write_proc = layer7_write_proc;
+}
+
+static int __init xt_layer7_init(void)
+{
+	need_conntrack();
+
+	layer7_init_proc();
+	if(maxdatalen < 1) {
+		printk(KERN_WARNING "layer7: maxdatalen can't be < 1, "
+			"using 1\n");
+		maxdatalen = 1;
+	}
+	/* This is not a hard limit.  It's just here to prevent people from
+	bringing their slow machines to a grinding halt. */
+	else if(maxdatalen > 65536) {
+		printk(KERN_WARNING "layer7: maxdatalen can't be > 65536, "
+			"using 65536\n");
+		maxdatalen = 65536;
+	}
+	return xt_register_matches(xt_layer7_match,
+				   ARRAY_SIZE(xt_layer7_match));
+}
+
+static void __exit xt_layer7_fini(void)
+{
+	layer7_cleanup_proc();
+	xt_unregister_matches(xt_layer7_match, ARRAY_SIZE(xt_layer7_match));
+}
+
+module_init(xt_layer7_init);
+module_exit(xt_layer7_fini);