--- /dev/null
+/*
+ * 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; ®dummy = 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
+
+
--- /dev/null
+/*
+ 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("2.23");
+
+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;
+ }
+ }
+}
+
+static int layer7_numpackets_proc_show(struct seq_file *s, void *p) {
+ seq_printf(s, "%d\n", num_packets);
+
+ return 0;
+}
+
+static int layer7_numpackets_proc_open(struct inode *inode, struct file *file) {
+ return single_open(file, layer7_numpackets_proc_show, NULL);
+}
+
+/* Read in num_packets from userland */
+static ssize_t layer7_numpackets_write_proc(struct file* file, const char __user *buffer,
+ size_t count, loff_t *data) {
+ char value[1024];
+ int new_num_packets;
+
+ if (copy_from_user(&value, buffer, sizeof(value)))
+ return -EFAULT;
+
+ new_num_packets = my_atoi(value);
+
+ if ((new_num_packets < 1) || (new_num_packets > 99)) {
+ printk(KERN_WARNING "layer7: numpackets must be between 1 and 99\n");
+ return -EFAULT;
+ }
+
+ num_packets = new_num_packets;
+
+ return count;
+}
+
+static bool
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 35)
+match(const struct sk_buff *skbin, struct xt_action_param *par)
+#elif LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 28)
+match(const struct sk_buff *skbin, const struct xt_match_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
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 35)
+static int
+#else
+static bool
+#endif
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 28)
+check(const struct xt_mtchk_param *par)
+{
+ if (nf_ct_l3proto_try_module_get(par->match->family) < 0) {
+ printk(KERN_WARNING "can't load conntrack support for "
+ "proto=%d\n", par->match->family);
+#else
+check(const char *tablename, const void *inf,
+ const struct xt_match *match, void *matchinfo,
+ unsigned int hook_mask)
+{
+ if (nf_ct_l3proto_try_module_get(match->family) < 0) {
+ printk(KERN_WARNING "can't load conntrack support for "
+ "proto=%d\n", match->family);
+#endif
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 35)
+ return -EINVAL;
+ }
+ return 0;
+#else
+ return 0;
+ }
+ return 1;
+#endif
+}
+
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 28)
+ static void destroy(const struct xt_mtdtor_param *par)
+ {
+ nf_ct_l3proto_module_put(par->match->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 const struct file_operations layer7_numpackets_proc_fops = {
+ .owner = THIS_MODULE,
+ .open = layer7_numpackets_proc_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+ .write = layer7_numpackets_write_proc,
+};
+
+static int __init xt_layer7_init(void)
+{
+ need_conntrack();
+
+ // Register proc interface
+ proc_create_data("layer7_numpackets", 0644,
+ init_net.proc_net, &layer7_numpackets_proc_fops, NULL);
+
+ 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)
+{
+ remove_proc_entry("layer7_numpackets", init_net.proc_net);
+ xt_unregister_matches(xt_layer7_match, ARRAY_SIZE(xt_layer7_match));
+}
+
+module_init(xt_layer7_init);
+module_exit(xt_layer7_fini);
+
projects / people / arne_f / kernel.git / commitdiff
