*
* Optimization module for tcpdump intermediate representation.
*/
-#ifndef lint
-static const char rcsid[] _U_ =
- "@(#) $Header: /tcpdump/master/libpcap/optimize.c,v 1.85 2005-04-04 08:42:18 guy Exp $ (LBL)";
-#endif
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
+#ifdef WIN32
+#include <pcap-stdinc.h>
+#else /* WIN32 */
+#if HAVE_INTTYPES_H
+#include <inttypes.h>
+#elif HAVE_STDINT_H
+#include <stdint.h>
+#endif
+#ifdef HAVE_SYS_BITYPES_H
+#include <sys/bitypes.h>
+#endif
+#include <sys/types.h>
+#endif /* WIN32 */
+
#include <stdio.h>
#include <stdlib.h>
#include <memory.h>
#define ffs _w32_ffs
#endif
+#if defined(WIN32) && defined (_MSC_VER)
+int ffs(int mask);
+#endif
+
/*
* Represents a deleted instruction.
*/
static void opt_init(struct block *);
static void opt_cleanup(void);
-static void make_marks(struct block *);
-static void mark_code(struct block *);
-
static void intern_blocks(struct block *);
-static int eq_slist(struct slist *, struct slist *);
-
-static void find_levels_r(struct block *);
-
-static void find_levels(struct block *);
-static void find_dom(struct block *);
-static void propedom(struct edge *);
-static void find_edom(struct block *);
-static void find_closure(struct block *);
-static int atomuse(struct stmt *);
-static int atomdef(struct stmt *);
-static void compute_local_ud(struct block *);
-static void find_ud(struct block *);
-static void init_val(void);
-static int F(int, int, int);
-static inline void vstore(struct stmt *, int *, int, int);
-static void opt_blk(struct block *, int);
-static int use_conflict(struct block *, struct block *);
-static void opt_j(struct edge *);
-static void or_pullup(struct block *);
-static void and_pullup(struct block *);
-static void opt_blks(struct block *, int);
-static inline void link_inedge(struct edge *, struct block *);
static void find_inedges(struct block *);
-static void opt_root(struct block **);
-static void opt_loop(struct block *, int);
-static void fold_op(struct stmt *, int, int);
-static inline struct slist *this_op(struct slist *);
-static void opt_not(struct block *);
-static void opt_peep(struct block *);
-static void opt_stmt(struct stmt *, int[], int);
-static void deadstmt(struct stmt *, struct stmt *[]);
-static void opt_deadstores(struct block *);
-static struct block *fold_edge(struct block *, struct edge *);
-static inline int eq_blk(struct block *, struct block *);
-static int slength(struct slist *);
-static int count_blocks(struct block *);
-static void number_blks_r(struct block *);
-static int count_stmts(struct block *);
-static int convert_code_r(struct block *);
#ifdef BDEBUG
static void opt_dump(struct block *);
#endif
#endif
static void
-find_levels_r(b)
- struct block *b;
+find_levels_r(struct block *b)
{
int level;
* with the 'link' field of the struct block.
*/
static void
-find_levels(root)
- struct block *root;
+find_levels(struct block *root)
{
memset((char *)levels, 0, n_blocks * sizeof(*levels));
unMarkAll();
* Assumes graph has been leveled.
*/
static void
-find_dom(root)
- struct block *root;
+find_dom(struct block *root)
{
int i;
struct block *b;
}
static void
-propedom(ep)
- struct edge *ep;
+propedom(struct edge *ep)
{
SET_INSERT(ep->edom, ep->id);
if (ep->succ) {
* Assumes graph has been leveled and predecessors established.
*/
static void
-find_edom(root)
- struct block *root;
+find_edom(struct block *root)
{
int i;
uset x;
* Assumes graph has been leveled.
*/
static void
-find_closure(root)
- struct block *root;
+find_closure(struct block *root)
{
int i;
struct block *b;
* The implementation should probably change to an array access.
*/
static int
-atomuse(s)
- struct stmt *s;
+atomuse(struct stmt *s)
{
register int c = s->code;
* The implementation should probably change to an array access.
*/
static int
-atomdef(s)
- struct stmt *s;
+atomdef(struct stmt *s)
{
if (s->code == NOP)
return -1;
* register by a predecessor block of this block.
*/
static void
-compute_local_ud(b)
- struct block *b;
+compute_local_ud(struct block *b)
{
struct slist *s;
atomset def = 0, use = 0, kill = 0;
* Assume graph is already leveled.
*/
static void
-find_ud(root)
- struct block *root;
+find_ud(struct block *root)
{
int i, maxlevel;
struct block *p;
struct valnode *next_vnode;
static void
-init_val()
+init_val(void)
{
curval = 0;
next_vnode = vnode_base;
/* Because we really don't have an IR, this stuff is a little messy. */
static int
-F(code, v0, v1)
- int code;
- int v0, v1;
+F(int code, int v0, int v1)
{
u_int hash;
int val;
}
static inline void
-vstore(s, valp, newval, alter)
- struct stmt *s;
- int *valp;
- int newval;
- int alter;
+vstore(struct stmt *s, int *valp, int newval, int alter)
{
if (alter && *valp == newval)
s->code = NOP;
*valp = newval;
}
+/*
+ * Do constant-folding on binary operators.
+ * (Unary operators are handled elsewhere.)
+ */
static void
-fold_op(s, v0, v1)
- struct stmt *s;
- int v0, v1;
+fold_op(struct stmt *s, int v0, int v1)
{
- bpf_int32 a, b;
+ bpf_u_int32 a, b;
a = vmap[v0].const_val;
b = vmap[v1].const_val;
a /= b;
break;
+ case BPF_MOD:
+ if (b == 0)
+ bpf_error("modulus by zero");
+ a %= b;
+ break;
+
case BPF_AND:
a &= b;
break;
a |= b;
break;
+ case BPF_XOR:
+ a ^= b;
+ break;
+
case BPF_LSH:
a <<= b;
break;
a >>= b;
break;
- case BPF_NEG:
- a = -a;
- break;
-
default:
abort();
}
}
static inline struct slist *
-this_op(s)
- struct slist *s;
+this_op(struct slist *s)
{
while (s != 0 && s->s.code == NOP)
s = s->next;
}
static void
-opt_not(b)
- struct block *b;
+opt_not(struct block *b)
{
struct block *tmp = JT(b);
}
static void
-opt_peep(b)
- struct block *b;
+opt_peep(struct block *b)
{
struct slist *s;
struct slist *next, *last;
if (b->s.k == 0xffffffff)
JF(b) = JT(b);
}
+ /*
+ * If we're comparing against the index register, and the index
+ * register is a known constant, we can just compare against that
+ * constant.
+ */
+ val = b->val[X_ATOM];
+ if (vmap[val].is_const && BPF_SRC(b->s.code) == BPF_X) {
+ bpf_int32 v = vmap[val].const_val;
+ b->s.code &= ~BPF_X;
+ b->s.k = v;
+ }
/*
* If the accumulator is a known constant, we can compute the
* comparison result.
* evaluation and code transformations weren't folded together.
*/
static void
-opt_stmt(s, val, alter)
- struct stmt *s;
- int val[];
- int alter;
+opt_stmt(struct stmt *s, int val[], int alter)
{
int op;
int v;
case BPF_ALU|BPF_SUB|BPF_K:
case BPF_ALU|BPF_MUL|BPF_K:
case BPF_ALU|BPF_DIV|BPF_K:
+ case BPF_ALU|BPF_MOD|BPF_K:
case BPF_ALU|BPF_AND|BPF_K:
case BPF_ALU|BPF_OR|BPF_K:
+ case BPF_ALU|BPF_XOR|BPF_K:
case BPF_ALU|BPF_LSH|BPF_K:
case BPF_ALU|BPF_RSH|BPF_K:
op = BPF_OP(s->code);
* fixup the generated math code */
if (op == BPF_ADD ||
op == BPF_LSH || op == BPF_RSH ||
- op == BPF_OR) {
+ op == BPF_OR || op == BPF_XOR) {
s->code = NOP;
break;
}
case BPF_ALU|BPF_SUB|BPF_X:
case BPF_ALU|BPF_MUL|BPF_X:
case BPF_ALU|BPF_DIV|BPF_X:
+ case BPF_ALU|BPF_MOD|BPF_X:
case BPF_ALU|BPF_AND|BPF_X:
case BPF_ALU|BPF_OR|BPF_X:
+ case BPF_ALU|BPF_XOR|BPF_X:
case BPF_ALU|BPF_LSH|BPF_X:
case BPF_ALU|BPF_RSH|BPF_X:
op = BPF_OP(s->code);
*/
if (alter && vmap[val[A_ATOM]].is_const
&& vmap[val[A_ATOM]].const_val == 0) {
- if (op == BPF_ADD || op == BPF_OR) {
+ if (op == BPF_ADD || op == BPF_OR || op == BPF_XOR) {
s->code = BPF_MISC|BPF_TXA;
vstore(s, &val[A_ATOM], val[X_ATOM], alter);
break;
}
- else if (op == BPF_MUL || op == BPF_DIV ||
+ else if (op == BPF_MUL || op == BPF_DIV || op == BPF_MOD ||
op == BPF_AND || op == BPF_LSH || op == BPF_RSH) {
s->code = BPF_LD|BPF_IMM;
s->k = 0;
}
static void
-deadstmt(s, last)
- register struct stmt *s;
- register struct stmt *last[];
+deadstmt(register struct stmt *s, register struct stmt *last[])
{
register int atom;
}
static void
-opt_deadstores(b)
- register struct block *b;
+opt_deadstores(register struct block *b)
{
register struct slist *s;
register int atom;
}
static void
-opt_blk(b, do_stmts)
- struct block *b;
- int do_stmts;
+opt_blk(struct block *b, int do_stmts)
{
struct slist *s;
struct edge *p;
* from 'b'.
*/
static int
-use_conflict(b, succ)
- struct block *b, *succ;
+use_conflict(struct block *b, struct block *succ)
{
int atom;
atomset use = succ->out_use;
}
static struct block *
-fold_edge(child, ep)
- struct block *child;
- struct edge *ep;
+fold_edge(struct block *child, struct edge *ep)
{
int sense;
int aval0, aval1, oval0, oval1;
}
static void
-opt_j(ep)
- struct edge *ep;
+opt_j(struct edge *ep)
{
register int i, k;
register struct block *target;
static void
-or_pullup(b)
- struct block *b;
+or_pullup(struct block *b)
{
int val, at_top;
struct block *pull;
}
static void
-and_pullup(b)
- struct block *b;
+and_pullup(struct block *b)
{
int val, at_top;
struct block *pull;
}
static void
-opt_blks(root, do_stmts)
- struct block *root;
- int do_stmts;
+opt_blks(struct block *root, int do_stmts)
{
int i, maxlevel;
struct block *p;
}
static inline void
-link_inedge(parent, child)
- struct edge *parent;
- struct block *child;
+link_inedge(struct edge *parent, struct block *child)
{
parent->next = child->in_edges;
child->in_edges = parent;
}
static void
-find_inedges(root)
- struct block *root;
+find_inedges(struct block *root)
{
int i;
struct block *b;
}
static void
-opt_root(b)
- struct block **b;
+opt_root(struct block **b)
{
struct slist *tmp, *s;
}
static void
-opt_loop(root, do_stmts)
- struct block *root;
- int do_stmts;
+opt_loop(struct block *root, int do_stmts)
{
#ifdef BDEBUG
* Optimize the filter code in its dag representation.
*/
void
-bpf_optimize(rootp)
- struct block **rootp;
+bpf_optimize(struct block **rootp)
{
struct block *root;
}
static void
-make_marks(p)
- struct block *p;
+make_marks(struct block *p)
{
if (!isMarked(p)) {
Mark(p);
* only for nodes that are alive.
*/
static void
-mark_code(p)
- struct block *p;
+mark_code(struct block *p)
{
cur_mark += 1;
make_marks(p);
* the accumulator.
*/
static int
-eq_slist(x, y)
- struct slist *x, *y;
+eq_slist(struct slist *x, struct slist *y)
{
while (1) {
while (x && x->s.code == NOP)
}
static inline int
-eq_blk(b0, b1)
- struct block *b0, *b1;
+eq_blk(struct block *b0, struct block *b1)
{
if (b0->s.code == b1->s.code &&
b0->s.k == b1->s.k &&
}
static void
-intern_blocks(root)
- struct block *root;
+intern_blocks(struct block *root)
{
struct block *p;
int i, j;
- int done;
+ int done1; /* don't shadow global */
top:
- done = 1;
+ done1 = 1;
for (i = 0; i < n_blocks; ++i)
blocks[i]->link = 0;
if (JT(p) == 0)
continue;
if (JT(p)->link) {
- done = 0;
+ done1 = 0;
JT(p) = JT(p)->link;
}
if (JF(p)->link) {
- done = 0;
+ done1 = 0;
JF(p) = JF(p)->link;
}
}
- if (!done)
+ if (!done1)
goto top;
}
static void
-opt_cleanup()
+opt_cleanup(void)
{
free((void *)vnode_base);
free((void *)vmap);
/*
* Return the number of stmts in 's'.
*/
-static int
-slength(s)
- struct slist *s;
+static u_int
+slength(struct slist *s)
{
- int n = 0;
+ u_int n = 0;
for (; s; s = s->next)
if (s->s.code != NOP)
* All nodes should be initially unmarked.
*/
static int
-count_blocks(p)
- struct block *p;
+count_blocks(struct block *p)
{
if (p == 0 || isMarked(p))
return 0;
* the basic blocks, and entering them into the 'blocks' array.`
*/
static void
-number_blks_r(p)
- struct block *p;
+number_blks_r(struct block *p)
{
int n;
*
* an extra long jump if the false branch requires it (p->longjf).
*/
-static int
-count_stmts(p)
- struct block *p;
+static u_int
+count_stmts(struct block *p)
{
- int n;
+ u_int n;
if (p == 0 || isMarked(p))
return 0;
* from the total number of blocks and/or statements.
*/
static void
-opt_init(root)
- struct block *root;
+opt_init(struct block *root)
{
bpf_u_int32 *p;
int i, n, max_stmts;
*/
unMarkAll();
n = count_blocks(root);
- blocks = (struct block **)malloc(n * sizeof(*blocks));
+ blocks = (struct block **)calloc(n, sizeof(*blocks));
if (blocks == NULL)
bpf_error("malloc");
unMarkAll();
number_blks_r(root);
n_edges = 2 * n_blocks;
- edges = (struct edge **)malloc(n_edges * sizeof(*edges));
+ edges = (struct edge **)calloc(n_edges, sizeof(*edges));
if (edges == NULL)
bpf_error("malloc");
/*
* The number of levels is bounded by the number of nodes.
*/
- levels = (struct block **)malloc(n_blocks * sizeof(*levels));
+ levels = (struct block **)calloc(n_blocks, sizeof(*levels));
if (levels == NULL)
bpf_error("malloc");
* we'll need.
*/
maxval = 3 * max_stmts;
- vmap = (struct vmapinfo *)malloc(maxval * sizeof(*vmap));
- vnode_base = (struct valnode *)malloc(maxval * sizeof(*vnode_base));
+ vmap = (struct vmapinfo *)calloc(maxval, sizeof(*vmap));
+ vnode_base = (struct valnode *)calloc(maxval, sizeof(*vnode_base));
if (vmap == NULL || vnode_base == NULL)
bpf_error("malloc");
}
* properly.
*/
static int
-convert_code_r(p)
- struct block *p;
+convert_code_r(struct block *p)
{
struct bpf_insn *dst;
struct slist *src;
{
int i;
int jt, jf;
- char *ljerr = "%s for block-local relative jump: off=%d";
+ const char *ljerr = "%s for block-local relative jump: off=%d";
#if 0
printf("code=%x off=%d %x %x\n", src->s.code,
/*
* Convert flowgraph intermediate representation to the
* BPF array representation. Set *lenp to the number of instructions.
+ *
+ * This routine does *NOT* leak the memory pointed to by fp. It *must
+ * not* do free(fp) before returning fp; doing so would make no sense,
+ * as the BPF array pointed to by the return value of icode_to_fcode()
+ * must be valid - it's being returned for use in a bpf_program structure.
+ *
+ * If it appears that icode_to_fcode() is leaking, the problem is that
+ * the program using pcap_compile() is failing to free the memory in
+ * the BPF program when it's done - the leak is in the program, not in
+ * the routine that happens to be allocating the memory. (By analogy, if
+ * a program calls fopen() without ever calling fclose() on the FILE *,
+ * it will leak the FILE structure; the leak is not in fopen(), it's in
+ * the program.) Change the program to use pcap_freecode() when it's
+ * done with the filter program. See the pcap man page.
*/
struct bpf_insn *
-icode_to_fcode(root, lenp)
- struct block *root;
- int *lenp;
+icode_to_fcode(struct block *root, u_int *lenp)
{
- int n;
+ u_int n;
struct bpf_insn *fp;
/*
{
size_t prog_size;
+ /*
+ * Validate the program.
+ */
+ if (!bpf_validate(fp->bf_insns, fp->bf_len)) {
+ snprintf(p->errbuf, sizeof(p->errbuf),
+ "BPF program is not valid");
+ return (-1);
+ }
+
/*
* Free up any already installed program.
*/
#ifdef BDEBUG
static void
-opt_dump(root)
- struct block *root;
+opt_dump(struct block *root)
{
struct bpf_program f;
projects / libpcap / blobdiff