File: [local] / src / lib / libpcap / gencode.c (download)
Revision 1.66, Mon Apr 8 02:51:14 2024 UTC (2 months ago) by jsg
Branch: MAIN
CVS Tags: HEAD
Changes since 1.65: +10 -14 lines
more ansi function decls
ok deraadt@
|
/* $OpenBSD: gencode.c,v 1.66 2024/04/08 02:51:14 jsg Exp $ */
/*
* Copyright (c) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that: (1) source code distributions
* retain the above copyright notice and this paragraph in its entirety, (2)
* distributions including binary code include the above copyright notice and
* this paragraph in its entirety in the documentation or other materials
* provided with the distribution, and (3) all advertising materials mentioning
* features or use of this software display the following acknowledgement:
* ``This product includes software developed by the University of California,
* Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
* the University nor the names of its contributors may be used to endorse
* or promote products derived from this software without specific prior
* written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <net/if.h>
#include <netinet/in.h>
#include <netinet/if_ether.h>
#include <net/if_pflog.h>
#include <net/pfvar.h>
#include <netmpls/mpls.h>
#include <net80211/ieee80211.h>
#include <net80211/ieee80211_radiotap.h>
#include <stdlib.h>
#include <stddef.h>
#include <setjmp.h>
#include <stdarg.h>
#include <string.h>
#include "pcap-int.h"
#include "ethertype.h"
#include "llc.h"
#include "gencode.h"
#include "ppp.h"
#include <pcap-namedb.h>
#ifdef INET6
#include <netdb.h>
#endif /*INET6*/
#ifdef HAVE_OS_PROTO_H
#include "os-proto.h"
#endif
#define JMP(c) ((c)|BPF_JMP|BPF_K)
/* Locals */
static jmp_buf top_ctx;
static pcap_t *bpf_pcap;
/* Hack for updating VLAN offsets. */
static u_int orig_linktype = -1, orig_nl = -1, orig_nl_nosnap = -1;
static u_int mpls_stack = 0;
/* XXX */
#ifdef PCAP_FDDIPAD
int pcap_fddipad = PCAP_FDDIPAD;
#else
int pcap_fddipad;
#endif
__dead void
bpf_error(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
if (bpf_pcap != NULL)
(void)vsnprintf(pcap_geterr(bpf_pcap), PCAP_ERRBUF_SIZE,
fmt, ap);
va_end(ap);
longjmp(top_ctx, 1);
/* NOTREACHED */
}
static void init_linktype(int);
static int alloc_reg(void);
static void free_reg(int);
static struct block *root;
/* initialization code used for variable link header */
static struct slist *init_code = NULL;
/* Flags and registers for variable link type handling */
static int variable_nl;
static int nl_reg, iphl_reg;
/*
* Track memory allocations, for bulk freeing at the end
*/
#define NMEMBAG 16
#define MEMBAG0SIZE (4096 / sizeof (void *))
struct membag {
u_int total;
u_int slot;
void **ptrs; /* allocated array[total] to each malloc */
};
static struct membag membag[NMEMBAG];
static int cur_membag;
static void *newchunk(size_t);
static void freechunks(void);
static __inline struct block *new_block(int);
static __inline struct slist *new_stmt(int);
static struct block *gen_retblk(int);
static __inline void syntax(void);
static void backpatch(struct block *, struct block *);
static void merge(struct block *, struct block *);
static struct block *gen_cmp(u_int, u_int, bpf_int32);
static struct block *gen_cmp_gt(u_int, u_int, bpf_int32);
static struct block *gen_cmp_nl(u_int, u_int, bpf_int32);
static struct block *gen_mcmp(u_int, u_int, bpf_int32, bpf_u_int32);
static struct block *gen_mcmp_nl(u_int, u_int, bpf_int32, bpf_u_int32);
static struct block *gen_bcmp(u_int, u_int, const u_char *);
static struct block *gen_uncond(int);
static __inline struct block *gen_true(void);
static __inline struct block *gen_false(void);
static struct block *gen_linktype(int);
static struct block *gen_hostop(bpf_u_int32, bpf_u_int32, int, int, u_int, u_int);
#ifdef INET6
static struct block *gen_hostop6(struct in6_addr *, struct in6_addr *, int, int, u_int, u_int);
#endif
static struct block *gen_ehostop(const u_char *, int);
static struct block *gen_fhostop(const u_char *, int);
static struct block *gen_dnhostop(bpf_u_int32, int, u_int);
static struct block *gen_p80211_hostop(const u_char *, int);
static struct block *gen_p80211_addr(int, u_int, const u_char *);
static struct block *gen_host(bpf_u_int32, bpf_u_int32, int, int);
#ifdef INET6
static struct block *gen_host6(struct in6_addr *, struct in6_addr *, int, int);
#endif
#ifndef INET6
static struct block *gen_gateway(const u_char *, bpf_u_int32 **, int, int);
#endif
static struct block *gen_ipfrag(void);
static struct block *gen_portatom(int, bpf_int32);
#ifdef INET6
static struct block *gen_portatom6(int, bpf_int32);
#endif
struct block *gen_portop(int, int, int);
static struct block *gen_port(int, int, int);
#ifdef INET6
struct block *gen_portop6(int, int, int);
static struct block *gen_port6(int, int, int);
#endif
static int lookup_proto(const char *, int);
static struct block *gen_protochain(int, int, int);
static struct block *gen_proto(int, int, int);
static struct slist *xfer_to_x(struct arth *);
static struct slist *xfer_to_a(struct arth *);
static struct block *gen_len(int, int);
static void *
newchunk(size_t n)
{
struct membag *m;
int k, size;
void *p;
m = &membag[cur_membag];
if (m->total != 0 && m->total - m->slot == 0) {
if (++cur_membag == NMEMBAG)
bpf_error("out of memory");
m = &membag[cur_membag];
}
if (m->total - m->slot == 0) {
m->ptrs = calloc(sizeof (char *), MEMBAG0SIZE << cur_membag);
if (m->ptrs == NULL)
bpf_error("out of memory");
m->total = MEMBAG0SIZE << cur_membag;
m->slot = 0;
}
p = calloc(1, n);
if (p == NULL)
bpf_error("out of memory");
m->ptrs[m->slot++] = p;
return (p);
}
static void
freechunks(void)
{
int i, j;
for (i = 0; i <= cur_membag; i++) {
if (membag[i].ptrs == NULL)
continue;
for (j = 0; j < membag[i].slot; j++)
free(membag[i].ptrs[j]);
free(membag[i].ptrs);
membag[i].ptrs = NULL;
membag[i].slot = membag[i].total = 0;
}
cur_membag = 0;
}
/*
* A strdup whose allocations are freed after code generation is over.
*/
char *
sdup(const char *s)
{
int n = strlen(s) + 1;
char *cp = newchunk(n);
strlcpy(cp, s, n);
return (cp);
}
static __inline struct block *
new_block(int code)
{
struct block *p;
p = (struct block *)newchunk(sizeof(*p));
p->s.code = code;
p->head = p;
return p;
}
static __inline struct slist *
new_stmt(int code)
{
struct slist *p;
p = (struct slist *)newchunk(sizeof(*p));
p->s.code = code;
return p;
}
static struct block *
gen_retblk(int v)
{
struct block *b = new_block(BPF_RET|BPF_K);
b->s.k = v;
return b;
}
static __inline void
syntax(void)
{
bpf_error("syntax error in filter expression");
}
static bpf_u_int32 netmask;
static int snaplen;
int no_optimize;
int
pcap_compile(pcap_t *p, struct bpf_program *program,
const char *buf, int optimize, bpf_u_int32 mask)
{
extern int n_errors;
int len;
no_optimize = 0;
n_errors = 0;
root = NULL;
bpf_pcap = p;
if (setjmp(top_ctx)) {
freechunks();
return (-1);
}
netmask = mask;
snaplen = pcap_snapshot(p);
lex_init(buf ? buf : "");
init_linktype(pcap_datalink(p));
(void)pcap_parse();
if (n_errors)
syntax();
if (root == NULL)
root = gen_retblk(snaplen);
if (optimize && !no_optimize) {
bpf_optimize(&root);
if (root == NULL ||
(root->s.code == (BPF_RET|BPF_K) && root->s.k == 0))
bpf_error("expression rejects all packets");
}
program->bf_insns = icode_to_fcode(root, &len);
program->bf_len = len;
freechunks();
return (0);
}
/*
* entry point for using the compiler with no pcap open
* pass in all the stuff that is needed explicitly instead.
*/
int
pcap_compile_nopcap(int snaplen_arg, int linktype_arg,
struct bpf_program *program,
const char *buf, int optimize, bpf_u_int32 mask)
{
extern int n_errors;
int len;
n_errors = 0;
root = NULL;
bpf_pcap = NULL;
if (setjmp(top_ctx)) {
freechunks();
return (-1);
}
netmask = mask;
/* XXX needed? I don't grok the use of globals here. */
snaplen = snaplen_arg;
lex_init(buf ? buf : "");
init_linktype(linktype_arg);
(void)pcap_parse();
if (n_errors)
syntax();
if (root == NULL)
root = gen_retblk(snaplen_arg);
if (optimize) {
bpf_optimize(&root);
if (root == NULL ||
(root->s.code == (BPF_RET|BPF_K) && root->s.k == 0))
bpf_error("expression rejects all packets");
}
program->bf_insns = icode_to_fcode(root, &len);
program->bf_len = len;
freechunks();
return (0);
}
/*
* Clean up a "struct bpf_program" by freeing all the memory allocated
* in it.
*/
void
pcap_freecode(struct bpf_program *program)
{
program->bf_len = 0;
if (program->bf_insns != NULL) {
free((char *)program->bf_insns);
program->bf_insns = NULL;
}
}
/*
* Backpatch the blocks in 'list' to 'target'. The 'sense' field indicates
* which of the jt and jf fields has been resolved and which is a pointer
* back to another unresolved block (or nil). At least one of the fields
* in each block is already resolved.
*/
static void
backpatch(struct block *list, struct block *target)
{
struct block *next;
while (list) {
if (!list->sense) {
next = JT(list);
JT(list) = target;
} else {
next = JF(list);
JF(list) = target;
}
list = next;
}
}
/*
* Merge the lists in b0 and b1, using the 'sense' field to indicate
* which of jt and jf is the link.
*/
static void
merge(struct block *b0, struct block *b1)
{
struct block **p = &b0;
/* Find end of list. */
while (*p)
p = !((*p)->sense) ? &JT(*p) : &JF(*p);
/* Concatenate the lists. */
*p = b1;
}
void
finish_parse(struct block *p)
{
backpatch(p, gen_retblk(snaplen));
p->sense = !p->sense;
backpatch(p, gen_retblk(0));
root = p->head;
/* prepend initialization code to root */
if (init_code != NULL && root != NULL) {
sappend(init_code, root->stmts);
root->stmts = init_code;
init_code = NULL;
}
if (iphl_reg != -1) {
free_reg(iphl_reg);
iphl_reg = -1;
}
if (nl_reg != -1) {
free_reg(nl_reg);
nl_reg = -1;
}
}
void
gen_and(struct block *b0, struct block *b1)
{
backpatch(b0, b1->head);
b0->sense = !b0->sense;
b1->sense = !b1->sense;
merge(b1, b0);
b1->sense = !b1->sense;
b1->head = b0->head;
}
void
gen_or(struct block *b0, struct block *b1)
{
b0->sense = !b0->sense;
backpatch(b0, b1->head);
b0->sense = !b0->sense;
merge(b1, b0);
b1->head = b0->head;
}
void
gen_not(struct block *b)
{
b->sense = !b->sense;
}
static struct block *
gen_cmp(u_int offset, u_int size, bpf_int32 v)
{
struct slist *s;
struct block *b;
s = new_stmt(BPF_LD|BPF_ABS|size);
s->s.k = offset;
b = new_block(JMP(BPF_JEQ));
b->stmts = s;
b->s.k = v;
return b;
}
static struct block *
gen_cmp_gt(u_int offset, u_int size, bpf_int32 v)
{
struct slist *s;
struct block *b;
s = new_stmt(BPF_LD|BPF_ABS|size);
s->s.k = offset;
b = new_block(JMP(BPF_JGT));
b->stmts = s;
b->s.k = v;
return b;
}
static struct block *
gen_mcmp(u_int offset, u_int size, bpf_int32 v, bpf_u_int32 mask)
{
struct block *b = gen_cmp(offset, size, v);
struct slist *s;
if (mask != 0xffffffff) {
s = new_stmt(BPF_ALU|BPF_AND|BPF_K);
s->s.k = mask;
sappend(b->stmts, s);
}
return b;
}
/* Like gen_mcmp with 'dynamic off_nl' added to the offset */
static struct block *
gen_mcmp_nl(u_int offset, u_int size, bpf_int32 v, bpf_u_int32 mask)
{
struct block *b = gen_cmp_nl(offset, size, v);
struct slist *s;
if (mask != 0xffffffff) {
s = new_stmt(BPF_ALU|BPF_AND|BPF_K);
s->s.k = mask;
sappend(b->stmts, s);
}
return b;
}
static struct block *
gen_bcmp(u_int offset, u_int size, const u_char *v)
{
struct block *b, *tmp;
b = NULL;
while (size >= 4) {
const u_char *p = &v[size - 4];
bpf_int32 w = ((bpf_int32)p[0] << 24) |
((bpf_int32)p[1] << 16) | ((bpf_int32)p[2] << 8) | p[3];
tmp = gen_cmp(offset + size - 4, BPF_W, w);
if (b != NULL)
gen_and(b, tmp);
b = tmp;
size -= 4;
}
while (size >= 2) {
const u_char *p = &v[size - 2];
bpf_int32 w = ((bpf_int32)p[0] << 8) | p[1];
tmp = gen_cmp(offset + size - 2, BPF_H, w);
if (b != NULL)
gen_and(b, tmp);
b = tmp;
size -= 2;
}
if (size > 0) {
tmp = gen_cmp(offset, BPF_B, (bpf_int32)v[0]);
if (b != NULL)
gen_and(b, tmp);
b = tmp;
}
return b;
}
/*
* Various code constructs need to know the layout of the data link
* layer. These variables give the necessary offsets. off_linktype
* is set to -1 for no encapsulation, in which case, IP is assumed.
*/
static u_int off_linktype;
static u_int off_nl;
static u_int off_nl_nosnap;
static int linktype;
/* Generate code to load the dynamic 'off_nl' to the X register */
static struct slist *
nl2X_stmt(void)
{
struct slist *s, *tmp;
if (nl_reg == -1) {
switch (linktype) {
case DLT_PFLOG:
/* The pflog header contains PFLOG_REAL_HDRLEN
which does NOT include the padding. Round
up to the nearest dword boundary */
s = new_stmt(BPF_LD|BPF_B|BPF_ABS);
s->s.k = 0;
tmp = new_stmt(BPF_ALU|BPF_ADD|BPF_K);
tmp->s.k = 3;
sappend(s, tmp);
tmp = new_stmt(BPF_ALU|BPF_AND|BPF_K);
tmp->s.k = 0xfc;
sappend(s, tmp);
nl_reg = alloc_reg();
tmp = new_stmt(BPF_ST);
tmp->s.k = nl_reg;
sappend(s, tmp);
break;
default:
bpf_error("Unknown header size for link type 0x%x",
linktype);
}
if (init_code == NULL)
init_code = s;
else
sappend(init_code, s);
}
s = new_stmt(BPF_LDX|BPF_MEM);
s->s.k = nl_reg;
return s;
}
/* Like gen_cmp but adds the dynamic 'off_nl' to the offset */
static struct block *
gen_cmp_nl(u_int offset, u_int size, bpf_int32 v)
{
struct slist *s, *tmp;
struct block *b;
if (variable_nl) {
s = nl2X_stmt();
tmp = new_stmt(BPF_LD|BPF_IND|size);
tmp->s.k = offset;
sappend(s, tmp);
} else {
s = new_stmt(BPF_LD|BPF_ABS|size);
s->s.k = offset + off_nl;
}
b = new_block(JMP(BPF_JEQ));
b->stmts = s;
b->s.k = v;
return b;
}
static void
init_linktype(int type)
{
linktype = type;
init_code = NULL;
nl_reg = iphl_reg = -1;
switch (type) {
case DLT_EN10MB:
off_linktype = 12;
off_nl = 14;
return;
case DLT_SLIP:
/*
* SLIP doesn't have a link level type. The 16 byte
* header is hacked into our SLIP driver.
*/
off_linktype = -1;
off_nl = 16;
return;
case DLT_SLIP_BSDOS:
/* XXX this may be the same as the DLT_PPP_BSDOS case */
off_linktype = -1;
/* XXX end */
off_nl = 24;
return;
case DLT_NULL:
off_linktype = 0;
off_nl = 4;
return;
case DLT_PPP:
off_linktype = 2;
off_nl = 4;
return;
case DLT_PPP_SERIAL:
off_linktype = -1;
off_nl = 2;
return;
case DLT_PPP_ETHER:
/*
* This does not include the Ethernet header, and
* only covers session state.
*/
off_linktype = 6;
off_nl = 8;
return;
case DLT_PPP_BSDOS:
off_linktype = 5;
off_nl = 24;
return;
case DLT_FDDI:
/*
* FDDI doesn't really have a link-level type field.
* We assume that SSAP = SNAP is being used and pick
* out the encapsulated Ethernet type.
*/
off_linktype = 19;
#ifdef PCAP_FDDIPAD
off_linktype += pcap_fddipad;
#endif
off_nl = 21;
#ifdef PCAP_FDDIPAD
off_nl += pcap_fddipad;
#endif
return;
case DLT_IEEE802:
off_linktype = 20;
off_nl = 22;
return;
case DLT_IEEE802_11:
off_linktype = 30; /* XXX variable */
off_nl = 32;
return;
case DLT_IEEE802_11_RADIO: /* XXX variable */
off_linktype = 30 + IEEE80211_RADIOTAP_HDRLEN;
off_nl = 32 + IEEE80211_RADIOTAP_HDRLEN;
return;
case DLT_ATM_RFC1483:
/*
* assume routed, non-ISO PDUs
* (i.e., LLC = 0xAA-AA-03, OUT = 0x00-00-00)
*/
off_linktype = 6;
off_nl = 8;
return;
case DLT_LOOP:
off_linktype = 0;
off_nl = 4;
return;
case DLT_ENC:
off_linktype = -1;
off_nl = 12;
return;
case DLT_PFLOG:
off_linktype = 0;
variable_nl = 1;
off_nl = 0;
return;
case DLT_PFSYNC:
off_linktype = -1;
off_nl = 4;
return;
case DLT_OPENFLOW:
off_linktype = -1;
off_nl = 12;
return;
case DLT_USBPCAP:
/* FALLTHROUGH */
case DLT_RAW:
off_linktype = -1;
off_nl = 0;
return;
}
bpf_error("unknown data link type 0x%x", linktype);
/* NOTREACHED */
}
static struct block *
gen_uncond(int rsense)
{
struct block *b;
struct slist *s;
s = new_stmt(BPF_LD|BPF_IMM);
s->s.k = !rsense;
b = new_block(JMP(BPF_JEQ));
b->stmts = s;
return b;
}
static __inline struct block *
gen_true(void)
{
return gen_uncond(1);
}
static __inline struct block *
gen_false(void)
{
return gen_uncond(0);
}
static struct block *
gen_linktype(int proto)
{
struct block *b0, *b1;
/* If we're not using encapsulation and checking for IP, we're done */
if ((off_linktype == -1 || mpls_stack > 0) && proto == ETHERTYPE_IP)
return gen_true();
#ifdef INET6
/* this isn't the right thing to do, but sometimes necessary */
if ((off_linktype == -1 || mpls_stack > 0) && proto == ETHERTYPE_IPV6)
return gen_true();
#endif
switch (linktype) {
case DLT_EN10MB:
if (proto <= ETHERMTU) {
/* This is an LLC SAP value */
b0 = gen_cmp_gt(off_linktype, BPF_H, ETHERMTU);
gen_not(b0);
b1 = gen_cmp(off_linktype + 2, BPF_B, (bpf_int32)proto);
gen_and(b0, b1);
return b1;
} else {
/* This is an Ethernet type */
return gen_cmp(off_linktype, BPF_H, (bpf_int32)proto);
}
break;
case DLT_SLIP:
return gen_false();
case DLT_PPP:
case DLT_PPP_ETHER:
if (proto == ETHERTYPE_IP)
proto = PPP_IP; /* XXX was 0x21 */
#ifdef INET6
else if (proto == ETHERTYPE_IPV6)
proto = PPP_IPV6;
#endif
break;
case DLT_PPP_BSDOS:
switch (proto) {
case ETHERTYPE_IP:
b0 = gen_cmp(off_linktype, BPF_H, PPP_IP);
b1 = gen_cmp(off_linktype, BPF_H, PPP_VJC);
gen_or(b0, b1);
b0 = gen_cmp(off_linktype, BPF_H, PPP_VJNC);
gen_or(b1, b0);
return b0;
#ifdef INET6
case ETHERTYPE_IPV6:
proto = PPP_IPV6;
/* more to go? */
break;
#endif /* INET6 */
case ETHERTYPE_DN:
proto = PPP_DECNET;
break;
case ETHERTYPE_ATALK:
proto = PPP_APPLE;
break;
case ETHERTYPE_NS:
proto = PPP_NS;
break;
}
break;
case DLT_LOOP:
case DLT_ENC:
case DLT_NULL:
{
int v;
if (proto == ETHERTYPE_IP)
v = AF_INET;
#ifdef INET6
else if (proto == ETHERTYPE_IPV6)
v = AF_INET6;
#endif /* INET6 */
else
return gen_false();
/*
* For DLT_NULL, the link-layer header is a 32-bit word
* containing an AF_ value in *host* byte order, and for
* DLT_ENC, the link-layer header begins with a 32-bit
* word containing an AF_ value in host byte order.
*
* For DLT_LOOP, the link-layer header is a 32-bit
* word containing an AF_ value in *network* byte order.
*/
if (linktype != DLT_LOOP)
v = htonl(v);
return (gen_cmp(0, BPF_W, (bpf_int32)v));
break;
}
case DLT_PFLOG:
if (proto == ETHERTYPE_IP)
return (gen_cmp(offsetof(struct pfloghdr, af), BPF_B,
(bpf_int32)AF_INET));
#ifdef INET6
else if (proto == ETHERTYPE_IPV6)
return (gen_cmp(offsetof(struct pfloghdr, af), BPF_B,
(bpf_int32)AF_INET6));
#endif /* INET6 */
else
return gen_false();
break;
}
return gen_cmp(off_linktype, BPF_H, (bpf_int32)proto);
}
static struct block *
gen_hostop(bpf_u_int32 addr, bpf_u_int32 mask, int dir, int proto,
u_int src_off, u_int dst_off)
{
struct block *b0, *b1;
u_int offset;
switch (dir) {
case Q_SRC:
offset = src_off;
break;
case Q_DST:
offset = dst_off;
break;
case Q_AND:
b0 = gen_hostop(addr, mask, Q_SRC, proto, src_off, dst_off);
b1 = gen_hostop(addr, mask, Q_DST, proto, src_off, dst_off);
gen_and(b0, b1);
return b1;
case Q_OR:
case Q_DEFAULT:
b0 = gen_hostop(addr, mask, Q_SRC, proto, src_off, dst_off);
b1 = gen_hostop(addr, mask, Q_DST, proto, src_off, dst_off);
gen_or(b0, b1);
return b1;
default:
bpf_error("direction not supported on linktype 0x%x",
linktype);
}
b0 = gen_linktype(proto);
b1 = gen_mcmp_nl(offset, BPF_W, (bpf_int32)addr, mask);
gen_and(b0, b1);
return b1;
}
#ifdef INET6
static struct block *
gen_hostop6(struct in6_addr *addr, struct in6_addr *mask, int dir, int proto,
u_int src_off, u_int dst_off)
{
struct block *b0, *b1;
u_int offset;
u_int32_t *a, *m;
switch (dir) {
case Q_SRC:
offset = src_off;
break;
case Q_DST:
offset = dst_off;
break;
case Q_AND:
b0 = gen_hostop6(addr, mask, Q_SRC, proto, src_off, dst_off);
b1 = gen_hostop6(addr, mask, Q_DST, proto, src_off, dst_off);
gen_and(b0, b1);
return b1;
case Q_OR:
case Q_DEFAULT:
b0 = gen_hostop6(addr, mask, Q_SRC, proto, src_off, dst_off);
b1 = gen_hostop6(addr, mask, Q_DST, proto, src_off, dst_off);
gen_or(b0, b1);
return b1;
default:
bpf_error("direction not supported on linktype 0x%x",
linktype);
}
/* this order is important */
a = (u_int32_t *)addr;
m = (u_int32_t *)mask;
b1 = gen_mcmp_nl(offset + 12, BPF_W, ntohl(a[3]), ntohl(m[3]));
b0 = gen_mcmp_nl(offset + 8, BPF_W, ntohl(a[2]), ntohl(m[2]));
gen_and(b0, b1);
b0 = gen_mcmp_nl(offset + 4, BPF_W, ntohl(a[1]), ntohl(m[1]));
gen_and(b0, b1);
b0 = gen_mcmp_nl(offset + 0, BPF_W, ntohl(a[0]), ntohl(m[0]));
gen_and(b0, b1);
b0 = gen_linktype(proto);
gen_and(b0, b1);
return b1;
}
#endif /*INET6*/
static struct block *
gen_ehostop(const u_char *eaddr, int dir)
{
struct block *b0, *b1;
switch (dir) {
case Q_SRC:
return gen_bcmp(6, 6, eaddr);
case Q_DST:
return gen_bcmp(0, 6, eaddr);
case Q_AND:
b0 = gen_ehostop(eaddr, Q_SRC);
b1 = gen_ehostop(eaddr, Q_DST);
gen_and(b0, b1);
return b1;
case Q_DEFAULT:
case Q_OR:
b0 = gen_ehostop(eaddr, Q_SRC);
b1 = gen_ehostop(eaddr, Q_DST);
gen_or(b0, b1);
return b1;
default:
bpf_error("direction not supported on linktype 0x%x",
linktype);
}
/* NOTREACHED */
}
/*
* Like gen_ehostop, but for DLT_FDDI
*/
static struct block *
gen_fhostop(const u_char *eaddr, int dir)
{
struct block *b0, *b1;
switch (dir) {
case Q_SRC:
#ifdef PCAP_FDDIPAD
return gen_bcmp(6 + 1 + pcap_fddipad, 6, eaddr);
#else
return gen_bcmp(6 + 1, 6, eaddr);
#endif
case Q_DST:
#ifdef PCAP_FDDIPAD
return gen_bcmp(0 + 1 + pcap_fddipad, 6, eaddr);
#else
return gen_bcmp(0 + 1, 6, eaddr);
#endif
case Q_AND:
b0 = gen_fhostop(eaddr, Q_SRC);
b1 = gen_fhostop(eaddr, Q_DST);
gen_and(b0, b1);
return b1;
case Q_DEFAULT:
case Q_OR:
b0 = gen_fhostop(eaddr, Q_SRC);
b1 = gen_fhostop(eaddr, Q_DST);
gen_or(b0, b1);
return b1;
default:
bpf_error("direction not supported on linktype 0x%x",
linktype);
}
/* NOTREACHED */
}
/*
* This is quite tricky because there may be pad bytes in front of the
* DECNET header, and then there are two possible data packet formats that
* carry both src and dst addresses, plus 5 packet types in a format that
* carries only the src node, plus 2 types that use a different format and
* also carry just the src node.
*
* Yuck.
*
* Instead of doing those all right, we just look for data packets with
* 0 or 1 bytes of padding. If you want to look at other packets, that
* will require a lot more hacking.
*
* To add support for filtering on DECNET "areas" (network numbers)
* one would want to add a "mask" argument to this routine. That would
* make the filter even more inefficient, although one could be clever
* and not generate masking instructions if the mask is 0xFFFF.
*/
static struct block *
gen_dnhostop(bpf_u_int32 addr, int dir, u_int base_off)
{
struct block *b0, *b1, *b2, *tmp;
u_int offset_lh; /* offset if long header is received */
u_int offset_sh; /* offset if short header is received */
switch (dir) {
case Q_DST:
offset_sh = 1; /* follows flags */
offset_lh = 7; /* flgs,darea,dsubarea,HIORD */
break;
case Q_SRC:
offset_sh = 3; /* follows flags, dstnode */
offset_lh = 15; /* flgs,darea,dsubarea,did,sarea,ssub,HIORD */
break;
case Q_AND:
/* Inefficient because we do our Calvinball dance twice */
b0 = gen_dnhostop(addr, Q_SRC, base_off);
b1 = gen_dnhostop(addr, Q_DST, base_off);
gen_and(b0, b1);
return b1;
case Q_OR:
case Q_DEFAULT:
/* Inefficient because we do our Calvinball dance twice */
b0 = gen_dnhostop(addr, Q_SRC, base_off);
b1 = gen_dnhostop(addr, Q_DST, base_off);
gen_or(b0, b1);
return b1;
default:
bpf_error("direction not supported on linktype 0x%x",
linktype);
}
b0 = gen_linktype(ETHERTYPE_DN);
/* Check for pad = 1, long header case */
tmp = gen_mcmp_nl(base_off + 2, BPF_H,
(bpf_int32)ntohs(0x0681), (bpf_int32)ntohs(0x07FF));
b1 = gen_cmp_nl(base_off + 2 + 1 + offset_lh,
BPF_H, (bpf_int32)ntohs(addr));
gen_and(tmp, b1);
/* Check for pad = 0, long header case */
tmp = gen_mcmp_nl(base_off + 2, BPF_B, (bpf_int32)0x06, (bpf_int32)0x7);
b2 = gen_cmp_nl(base_off + 2 + offset_lh, BPF_H, (bpf_int32)ntohs(addr));
gen_and(tmp, b2);
gen_or(b2, b1);
/* Check for pad = 1, short header case */
tmp = gen_mcmp_nl(base_off + 2, BPF_H,
(bpf_int32)ntohs(0x0281), (bpf_int32)ntohs(0x07FF));
b2 = gen_cmp_nl(base_off + 2 + 1 + offset_sh,
BPF_H, (bpf_int32)ntohs(addr));
gen_and(tmp, b2);
gen_or(b2, b1);
/* Check for pad = 0, short header case */
tmp = gen_mcmp_nl(base_off + 2, BPF_B, (bpf_int32)0x02, (bpf_int32)0x7);
b2 = gen_cmp_nl(base_off + 2 + offset_sh, BPF_H, (bpf_int32)ntohs(addr));
gen_and(tmp, b2);
gen_or(b2, b1);
/* Combine with test for linktype */
gen_and(b0, b1);
return b1;
}
static struct block *
gen_host(bpf_u_int32 addr, bpf_u_int32 mask, int proto, int dir)
{
struct block *b0, *b1;
switch (proto) {
case Q_DEFAULT:
b0 = gen_host(addr, mask, Q_IP, dir);
b1 = gen_host(addr, mask, Q_ARP, dir);
gen_or(b0, b1);
b0 = gen_host(addr, mask, Q_RARP, dir);
gen_or(b1, b0);
return b0;
case Q_IP:
return gen_hostop(addr, mask, dir, ETHERTYPE_IP,
12, 16);
case Q_RARP:
return gen_hostop(addr, mask, dir, ETHERTYPE_REVARP,
14, 24);
case Q_ARP:
return gen_hostop(addr, mask, dir, ETHERTYPE_ARP,
14, 24);
case Q_TCP:
bpf_error("'tcp' modifier applied to host");
case Q_UDP:
bpf_error("'udp' modifier applied to host");
case Q_ICMP:
bpf_error("'icmp' modifier applied to host");
case Q_IGMP:
bpf_error("'igmp' modifier applied to host");
case Q_IGRP:
bpf_error("'igrp' modifier applied to host");
case Q_PIM:
bpf_error("'pim' modifier applied to host");
case Q_STP:
bpf_error("'stp' modifier applied to host");
case Q_ATALK:
bpf_error("ATALK host filtering not implemented");
case Q_DECNET:
return gen_dnhostop(addr, dir, 0);
case Q_SCA:
bpf_error("SCA host filtering not implemented");
case Q_LAT:
bpf_error("LAT host filtering not implemented");
case Q_MOPDL:
bpf_error("MOPDL host filtering not implemented");
case Q_MOPRC:
bpf_error("MOPRC host filtering not implemented");
#ifdef INET6
case Q_IPV6:
bpf_error("'ip6' modifier applied to ip host");
case Q_ICMPV6:
bpf_error("'icmp6' modifier applied to host");
#endif /* INET6 */
case Q_AH:
bpf_error("'ah' modifier applied to host");
case Q_ESP:
bpf_error("'esp' modifier applied to host");
default:
bpf_error("direction not supported on linktype 0x%x",
linktype);
}
/* NOTREACHED */
}
#ifdef INET6
static struct block *
gen_host6(struct in6_addr *addr, struct in6_addr *mask, int proto, int dir)
{
switch (proto) {
case Q_DEFAULT:
return gen_host6(addr, mask, Q_IPV6, dir);
case Q_IP:
bpf_error("'ip' modifier applied to ip6 host");
case Q_RARP:
bpf_error("'rarp' modifier applied to ip6 host");
case Q_ARP:
bpf_error("'arp' modifier applied to ip6 host");
case Q_TCP:
bpf_error("'tcp' modifier applied to host");
case Q_UDP:
bpf_error("'udp' modifier applied to host");
case Q_ICMP:
bpf_error("'icmp' modifier applied to host");
case Q_IGMP:
bpf_error("'igmp' modifier applied to host");
case Q_IGRP:
bpf_error("'igrp' modifier applied to host");
case Q_PIM:
bpf_error("'pim' modifier applied to host");
case Q_STP:
bpf_error("'stp' modifier applied to host");
case Q_ATALK:
bpf_error("ATALK host filtering not implemented");
case Q_DECNET:
bpf_error("'decnet' modifier applied to ip6 host");
case Q_SCA:
bpf_error("SCA host filtering not implemented");
case Q_LAT:
bpf_error("LAT host filtering not implemented");
case Q_MOPDL:
bpf_error("MOPDL host filtering not implemented");
case Q_MOPRC:
bpf_error("MOPRC host filtering not implemented");
case Q_IPV6:
return gen_hostop6(addr, mask, dir, ETHERTYPE_IPV6,
8, 24);
case Q_ICMPV6:
bpf_error("'icmp6' modifier applied to host");
case Q_AH:
bpf_error("'ah' modifier applied to host");
case Q_ESP:
bpf_error("'esp' modifier applied to host");
default:
abort();
}
/* NOTREACHED */
}
#endif /*INET6*/
#ifndef INET6
static struct block *
gen_gateway(const u_char *eaddr, bpf_u_int32 **alist, int proto, int dir)
{
struct block *b0, *b1, *tmp;
if (dir != 0)
bpf_error("direction applied to 'gateway'");
switch (proto) {
case Q_DEFAULT:
case Q_IP:
case Q_ARP:
case Q_RARP:
if (linktype == DLT_EN10MB)
b0 = gen_ehostop(eaddr, Q_OR);
else if (linktype == DLT_FDDI)
b0 = gen_fhostop(eaddr, Q_OR);
else
bpf_error(
"'gateway' supported only on ethernet or FDDI");
b1 = gen_host(**alist++, 0xffffffff, proto, Q_OR);
while (*alist) {
tmp = gen_host(**alist++, 0xffffffff, proto, Q_OR);
gen_or(b1, tmp);
b1 = tmp;
}
gen_not(b1);
gen_and(b0, b1);
return b1;
}
bpf_error("illegal modifier of 'gateway'");
/* NOTREACHED */
}
#endif /*INET6*/
struct block *
gen_proto_abbrev(int proto)
{
struct block *b0 = NULL, *b1;
switch (proto) {
case Q_TCP:
b1 = gen_proto(IPPROTO_TCP, Q_IP, Q_DEFAULT);
#ifdef INET6
b0 = gen_proto(IPPROTO_TCP, Q_IPV6, Q_DEFAULT);
gen_or(b0, b1);
#endif
break;
case Q_UDP:
b1 = gen_proto(IPPROTO_UDP, Q_IP, Q_DEFAULT);
#ifdef INET6
b0 = gen_proto(IPPROTO_UDP, Q_IPV6, Q_DEFAULT);
gen_or(b0, b1);
#endif
break;
case Q_ICMP:
b1 = gen_proto(IPPROTO_ICMP, Q_IP, Q_DEFAULT);
break;
#ifndef IPPROTO_IGMP
#define IPPROTO_IGMP 2
#endif
case Q_IGMP:
b1 = gen_proto(IPPROTO_IGMP, Q_IP, Q_DEFAULT);
break;
#ifndef IPPROTO_IGRP
#define IPPROTO_IGRP 9
#endif
case Q_IGRP:
b1 = gen_proto(IPPROTO_IGRP, Q_IP, Q_DEFAULT);
break;
#ifndef IPPROTO_PIM
#define IPPROTO_PIM 103
#endif
case Q_PIM:
b1 = gen_proto(IPPROTO_PIM, Q_IP, Q_DEFAULT);
#ifdef INET6
b0 = gen_proto(IPPROTO_PIM, Q_IPV6, Q_DEFAULT);
gen_or(b0, b1);
#endif
break;
case Q_IP:
b1 = gen_linktype(ETHERTYPE_IP);
break;
case Q_ARP:
b1 = gen_linktype(ETHERTYPE_ARP);
break;
case Q_RARP:
b1 = gen_linktype(ETHERTYPE_REVARP);
break;
case Q_LINK:
bpf_error("link layer applied in wrong context");
case Q_ATALK:
b1 = gen_linktype(ETHERTYPE_ATALK);
break;
case Q_DECNET:
b1 = gen_linktype(ETHERTYPE_DN);
break;
case Q_SCA:
b1 = gen_linktype(ETHERTYPE_SCA);
break;
case Q_LAT:
b1 = gen_linktype(ETHERTYPE_LAT);
break;
case Q_MOPDL:
b1 = gen_linktype(ETHERTYPE_MOPDL);
break;
case Q_MOPRC:
b1 = gen_linktype(ETHERTYPE_MOPRC);
break;
case Q_STP:
b1 = gen_linktype(LLCSAP_8021D);
break;
#ifdef INET6
case Q_IPV6:
b1 = gen_linktype(ETHERTYPE_IPV6);
break;
#ifndef IPPROTO_ICMPV6
#define IPPROTO_ICMPV6 58
#endif
case Q_ICMPV6:
b1 = gen_proto(IPPROTO_ICMPV6, Q_IPV6, Q_DEFAULT);
break;
#endif /* INET6 */
#ifndef IPPROTO_AH
#define IPPROTO_AH 51
#endif
case Q_AH:
b1 = gen_proto(IPPROTO_AH, Q_IP, Q_DEFAULT);
#ifdef INET6
b0 = gen_proto(IPPROTO_AH, Q_IPV6, Q_DEFAULT);
gen_or(b0, b1);
#endif
break;
#ifndef IPPROTO_ESP
#define IPPROTO_ESP 50
#endif
case Q_ESP:
b1 = gen_proto(IPPROTO_ESP, Q_IP, Q_DEFAULT);
#ifdef INET6
b0 = gen_proto(IPPROTO_ESP, Q_IPV6, Q_DEFAULT);
gen_or(b0, b1);
#endif
break;
default:
abort();
}
return b1;
}
static struct block *
gen_ipfrag(void)
{
struct slist *s, *tmp;
struct block *b;
/* not ip frag */
if (variable_nl) {
s = nl2X_stmt();
tmp = new_stmt(BPF_LD|BPF_H|BPF_IND);
tmp->s.k = 6;
sappend(s, tmp);
} else {
s = new_stmt(BPF_LD|BPF_H|BPF_ABS);
s->s.k = off_nl + 6;
}
b = new_block(JMP(BPF_JSET));
b->s.k = 0x1fff;
b->stmts = s;
gen_not(b);
return b;
}
/* For dynamic off_nl, the BPF_LDX|BPF_MSH instruction does not work
This function generates code to set X to the start of the IP payload
X = off_nl + IP header_len.
*/
static struct slist *
iphl_to_x(void)
{
struct slist *s, *tmp;
/* XXX clobbers A if variable_nl*/
if (variable_nl) {
if (iphl_reg == -1) {
/* X <- off_nl */
s = nl2X_stmt();
/* A = p[X+0] */
tmp = new_stmt(BPF_LD|BPF_B|BPF_IND);
tmp->s.k = 0;
sappend(s, tmp);
/* A = A & 0x0f */
tmp = new_stmt(BPF_ALU|BPF_AND|BPF_K);
tmp->s.k = 0x0f;
sappend(s, tmp);
/* A = A << 2 */
tmp = new_stmt(BPF_ALU|BPF_LSH|BPF_K);
tmp->s.k = 2;
sappend(s, tmp);
/* A = A + X (add off_nl again to compensate) */
sappend(s, new_stmt(BPF_ALU|BPF_ADD|BPF_X));
/* MEM[iphl_reg] = A */
iphl_reg = alloc_reg();
tmp = new_stmt(BPF_ST);
tmp->s.k = iphl_reg;
sappend(s, tmp);
sappend(init_code, s);
}
s = new_stmt(BPF_LDX|BPF_MEM);
s->s.k = iphl_reg;
} else {
s = new_stmt(BPF_LDX|BPF_MSH|BPF_B);
s->s.k = off_nl;
}
return s;
}
static struct block *
gen_portatom(int off, bpf_int32 v)
{
struct slist *s, *tmp;
struct block *b;
s = iphl_to_x();
tmp = new_stmt(BPF_LD|BPF_IND|BPF_H);
tmp->s.k = off_nl + off; /* off_nl == 0 if variable_nl */
sappend(s, tmp);
b = new_block(JMP(BPF_JEQ));
b->stmts = s;
b->s.k = v;
return b;
}
#ifdef INET6
static struct block *
gen_portatom6(int off, bpf_int32 v)
{
return gen_cmp_nl(40 + off, BPF_H, v);
}
#endif/*INET6*/
struct block *
gen_portop(int port, int proto, int dir)
{
struct block *b0, *b1, *tmp;
/* ip proto 'proto' */
tmp = gen_cmp_nl(9, BPF_B, (bpf_int32)proto);
b0 = gen_ipfrag();
gen_and(tmp, b0);
switch (dir) {
case Q_SRC:
b1 = gen_portatom(0, (bpf_int32)port);
break;
case Q_DST:
b1 = gen_portatom(2, (bpf_int32)port);
break;
case Q_OR:
case Q_DEFAULT:
tmp = gen_portatom(0, (bpf_int32)port);
b1 = gen_portatom(2, (bpf_int32)port);
gen_or(tmp, b1);
break;
case Q_AND:
tmp = gen_portatom(0, (bpf_int32)port);
b1 = gen_portatom(2, (bpf_int32)port);
gen_and(tmp, b1);
break;
default:
abort();
}
gen_and(b0, b1);
return b1;
}
static struct block *
gen_port(int port, int ip_proto, int dir)
{
struct block *b0, *b1, *tmp;
/* ether proto ip */
b0 = gen_linktype(ETHERTYPE_IP);
switch (ip_proto) {
case IPPROTO_UDP:
case IPPROTO_TCP:
b1 = gen_portop(port, ip_proto, dir);
break;
case PROTO_UNDEF:
tmp = gen_portop(port, IPPROTO_TCP, dir);
b1 = gen_portop(port, IPPROTO_UDP, dir);
gen_or(tmp, b1);
break;
default:
abort();
}
gen_and(b0, b1);
return b1;
}
#ifdef INET6
struct block *
gen_portop6(int port, int proto, int dir)
{
struct block *b0, *b1, *tmp;
/* ip proto 'proto' */
b0 = gen_cmp_nl(6, BPF_B, (bpf_int32)proto);
switch (dir) {
case Q_SRC:
b1 = gen_portatom6(0, (bpf_int32)port);
break;
case Q_DST:
b1 = gen_portatom6(2, (bpf_int32)port);
break;
case Q_OR:
case Q_DEFAULT:
tmp = gen_portatom6(0, (bpf_int32)port);
b1 = gen_portatom6(2, (bpf_int32)port);
gen_or(tmp, b1);
break;
case Q_AND:
tmp = gen_portatom6(0, (bpf_int32)port);
b1 = gen_portatom6(2, (bpf_int32)port);
gen_and(tmp, b1);
break;
default:
abort();
}
gen_and(b0, b1);
return b1;
}
static struct block *
gen_port6(int port, int ip_proto, int dir)
{
struct block *b0, *b1, *tmp;
/* ether proto ip */
b0 = gen_linktype(ETHERTYPE_IPV6);
switch (ip_proto) {
case IPPROTO_UDP:
case IPPROTO_TCP:
b1 = gen_portop6(port, ip_proto, dir);
break;
case PROTO_UNDEF:
tmp = gen_portop6(port, IPPROTO_TCP, dir);
b1 = gen_portop6(port, IPPROTO_UDP, dir);
gen_or(tmp, b1);
break;
default:
abort();
}
gen_and(b0, b1);
return b1;
}
#endif /* INET6 */
static int
lookup_proto(const char *name, int proto)
{
int v;
switch (proto) {
case Q_DEFAULT:
case Q_IP:
v = pcap_nametoproto(name);
if (v == PROTO_UNDEF)
bpf_error("unknown ip proto '%s'", name);
break;
case Q_LINK:
/* XXX should look up h/w protocol type based on linktype */
v = pcap_nametoeproto(name);
if (v == PROTO_UNDEF) {
v = pcap_nametollc(name);
if (v == PROTO_UNDEF)
bpf_error("unknown ether proto '%s'", name);
}
break;
default:
v = PROTO_UNDEF;
break;
}
return v;
}
static struct block *
gen_protochain(int v, int proto, int dir)
{
struct block *b0, *b;
struct slist *s[100];
int fix2, fix3, fix4, fix5;
int ahcheck, again, end;
int i, max;
int reg1 = alloc_reg();
int reg2 = alloc_reg();
memset(s, 0, sizeof(s));
fix2 = fix3 = fix4 = fix5 = 0;
if (variable_nl) {
bpf_error("'gen_protochain' not supported for variable DLTs");
/*NOTREACHED*/
}
switch (proto) {
case Q_IP:
case Q_IPV6:
break;
case Q_DEFAULT:
b0 = gen_protochain(v, Q_IP, dir);
b = gen_protochain(v, Q_IPV6, dir);
gen_or(b0, b);
return b;
default:
bpf_error("bad protocol applied for 'protochain'");
/*NOTREACHED*/
}
no_optimize = 1; /*this code is not compatible with optimzer yet */
/*
* s[0] is a dummy entry to protect other BPF insn from damaged
* by s[fix] = foo with uninitialized variable "fix". It is somewhat
* hard to find interdependency made by jump table fixup.
*/
i = 0;
s[i] = new_stmt(0); /*dummy*/
i++;
switch (proto) {
case Q_IP:
b0 = gen_linktype(ETHERTYPE_IP);
/* A = ip->ip_p */
s[i] = new_stmt(BPF_LD|BPF_ABS|BPF_B);
s[i]->s.k = off_nl + 9;
i++;
/* X = ip->ip_hl << 2 */
s[i] = new_stmt(BPF_LDX|BPF_MSH|BPF_B);
s[i]->s.k = off_nl;
i++;
break;
case Q_IPV6:
b0 = gen_linktype(ETHERTYPE_IPV6);
/* A = ip6->ip_nxt */
s[i] = new_stmt(BPF_LD|BPF_ABS|BPF_B);
s[i]->s.k = off_nl + 6;
i++;
/* X = sizeof(struct ip6_hdr) */
s[i] = new_stmt(BPF_LDX|BPF_IMM);
s[i]->s.k = 40;
i++;
break;
default:
bpf_error("unsupported proto to gen_protochain");
/*NOTREACHED*/
}
/* again: if (A == v) goto end; else fall through; */
again = i;
s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K);
s[i]->s.k = v;
s[i]->s.jt = NULL; /*later*/
s[i]->s.jf = NULL; /*update in next stmt*/
fix5 = i;
i++;
/* if (A == IPPROTO_NONE) goto end */
s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K);
s[i]->s.jt = NULL; /*later*/
s[i]->s.jf = NULL; /*update in next stmt*/
s[i]->s.k = IPPROTO_NONE;
s[fix5]->s.jf = s[i];
fix2 = i;
i++;
if (proto == Q_IPV6) {
int v6start, v6end, v6advance, j;
v6start = i;
/* if (A == IPPROTO_HOPOPTS) goto v6advance */
s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K);
s[i]->s.jt = NULL; /*later*/
s[i]->s.jf = NULL; /*update in next stmt*/
s[i]->s.k = IPPROTO_HOPOPTS;
s[fix2]->s.jf = s[i];
i++;
/* if (A == IPPROTO_DSTOPTS) goto v6advance */
s[i - 1]->s.jf = s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K);
s[i]->s.jt = NULL; /*later*/
s[i]->s.jf = NULL; /*update in next stmt*/
s[i]->s.k = IPPROTO_DSTOPTS;
i++;
/* if (A == IPPROTO_ROUTING) goto v6advance */
s[i - 1]->s.jf = s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K);
s[i]->s.jt = NULL; /*later*/
s[i]->s.jf = NULL; /*update in next stmt*/
s[i]->s.k = IPPROTO_ROUTING;
i++;
/* if (A == IPPROTO_FRAGMENT) goto v6advance; else goto ahcheck; */
s[i - 1]->s.jf = s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K);
s[i]->s.jt = NULL; /*later*/
s[i]->s.jf = NULL; /*later*/
s[i]->s.k = IPPROTO_FRAGMENT;
fix3 = i;
v6end = i;
i++;
/* v6advance: */
v6advance = i;
/*
* in short,
* A = P[X + 1];
* X = X + (P[X] + 1) * 8;
*/
/* A = X */
s[i] = new_stmt(BPF_MISC|BPF_TXA);
i++;
/* MEM[reg1] = A */
s[i] = new_stmt(BPF_ST);
s[i]->s.k = reg1;
i++;
/* A += 1 */
s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K);
s[i]->s.k = 1;
i++;
/* X = A */
s[i] = new_stmt(BPF_MISC|BPF_TAX);
i++;
/* A = P[X + packet head]; */
s[i] = new_stmt(BPF_LD|BPF_IND|BPF_B);
s[i]->s.k = off_nl;
i++;
/* MEM[reg2] = A */
s[i] = new_stmt(BPF_ST);
s[i]->s.k = reg2;
i++;
/* X = MEM[reg1] */
s[i] = new_stmt(BPF_LDX|BPF_MEM);
s[i]->s.k = reg1;
i++;
/* A = P[X + packet head] */
s[i] = new_stmt(BPF_LD|BPF_IND|BPF_B);
s[i]->s.k = off_nl;
i++;
/* A += 1 */
s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K);
s[i]->s.k = 1;
i++;
/* A *= 8 */
s[i] = new_stmt(BPF_ALU|BPF_MUL|BPF_K);
s[i]->s.k = 8;
i++;
/* X = A; */
s[i] = new_stmt(BPF_MISC|BPF_TAX);
i++;
/* A = MEM[reg2] */
s[i] = new_stmt(BPF_LD|BPF_MEM);
s[i]->s.k = reg2;
i++;
/* goto again; (must use BPF_JA for backward jump) */
s[i] = new_stmt(BPF_JMP|BPF_JA);
s[i]->s.k = again - i - 1;
s[i - 1]->s.jf = s[i];
i++;
/* fixup */
for (j = v6start; j <= v6end; j++)
s[j]->s.jt = s[v6advance];
} else {
/* nop */
s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K);
s[i]->s.k = 0;
s[fix2]->s.jf = s[i];
i++;
}
/* ahcheck: */
ahcheck = i;
/* if (A == IPPROTO_AH) then fall through; else goto end; */
s[i] = new_stmt(BPF_JMP|BPF_JEQ|BPF_K);
s[i]->s.jt = NULL; /*later*/
s[i]->s.jf = NULL; /*later*/
s[i]->s.k = IPPROTO_AH;
if (fix3)
s[fix3]->s.jf = s[ahcheck];
fix4 = i;
i++;
/*
* in short,
* A = P[X + 1];
* X = X + (P[X] + 2) * 4;
*/
/* A = X */
s[i - 1]->s.jt = s[i] = new_stmt(BPF_MISC|BPF_TXA);
i++;
/* MEM[reg1] = A */
s[i] = new_stmt(BPF_ST);
s[i]->s.k = reg1;
i++;
/* A += 1 */
s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K);
s[i]->s.k = 1;
i++;
/* X = A */
s[i] = new_stmt(BPF_MISC|BPF_TAX);
i++;
/* A = P[X + packet head]; */
s[i] = new_stmt(BPF_LD|BPF_IND|BPF_B);
s[i]->s.k = off_nl;
i++;
/* MEM[reg2] = A */
s[i] = new_stmt(BPF_ST);
s[i]->s.k = reg2;
i++;
/* X = MEM[reg1] */
s[i] = new_stmt(BPF_LDX|BPF_MEM);
s[i]->s.k = reg1;
i++;
/* A = P[X + packet head] */
s[i] = new_stmt(BPF_LD|BPF_IND|BPF_B);
s[i]->s.k = off_nl;
i++;
/* A += 2 */
s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K);
s[i]->s.k = 2;
i++;
/* A *= 4 */
s[i] = new_stmt(BPF_ALU|BPF_MUL|BPF_K);
s[i]->s.k = 4;
i++;
/* X = A; */
s[i] = new_stmt(BPF_MISC|BPF_TAX);
i++;
/* A = MEM[reg2] */
s[i] = new_stmt(BPF_LD|BPF_MEM);
s[i]->s.k = reg2;
i++;
/* goto again; (must use BPF_JA for backward jump) */
s[i] = new_stmt(BPF_JMP|BPF_JA);
s[i]->s.k = again - i - 1;
i++;
/* end: nop */
end = i;
s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K);
s[i]->s.k = 0;
s[fix2]->s.jt = s[end];
s[fix4]->s.jf = s[end];
s[fix5]->s.jt = s[end];
i++;
/*
* make slist chain
*/
max = i;
for (i = 0; i < max - 1; i++)
s[i]->next = s[i + 1];
s[max - 1]->next = NULL;
/*
* emit final check
*/
b = new_block(JMP(BPF_JEQ));
b->stmts = s[1]; /*remember, s[0] is dummy*/
b->s.k = v;
free_reg(reg1);
free_reg(reg2);
gen_and(b0, b);
return b;
}
static struct block *
gen_proto(int v, int proto, int dir)
{
struct block *b0, *b1;
if (dir != Q_DEFAULT)
bpf_error("direction applied to 'proto'");
switch (proto) {
case Q_DEFAULT:
#ifdef INET6
b0 = gen_proto(v, Q_IP, dir);
b1 = gen_proto(v, Q_IPV6, dir);
gen_or(b0, b1);
return b1;
#else
/*FALLTHROUGH*/
#endif
case Q_IP:
b0 = gen_linktype(ETHERTYPE_IP);
#ifndef CHASE_CHAIN
b1 = gen_cmp_nl(9, BPF_B, (bpf_int32)v);
#else
b1 = gen_protochain(v, Q_IP);
#endif
gen_and(b0, b1);
return b1;
case Q_ARP:
bpf_error("arp does not encapsulate another protocol");
/* NOTREACHED */
case Q_RARP:
bpf_error("rarp does not encapsulate another protocol");
/* NOTREACHED */
case Q_ATALK:
bpf_error("atalk encapsulation is not specifiable");
/* NOTREACHED */
case Q_DECNET:
bpf_error("decnet encapsulation is not specifiable");
/* NOTREACHED */
case Q_SCA:
bpf_error("sca does not encapsulate another protocol");
/* NOTREACHED */
case Q_LAT:
bpf_error("lat does not encapsulate another protocol");
/* NOTREACHED */
case Q_MOPRC:
bpf_error("moprc does not encapsulate another protocol");
/* NOTREACHED */
case Q_MOPDL:
bpf_error("mopdl does not encapsulate another protocol");
/* NOTREACHED */
case Q_LINK:
return gen_linktype(v);
case Q_UDP:
bpf_error("'udp proto' is bogus");
/* NOTREACHED */
case Q_TCP:
bpf_error("'tcp proto' is bogus");
/* NOTREACHED */
case Q_ICMP:
bpf_error("'icmp proto' is bogus");
/* NOTREACHED */
case Q_IGMP:
bpf_error("'igmp proto' is bogus");
/* NOTREACHED */
case Q_IGRP:
bpf_error("'igrp proto' is bogus");
/* NOTREACHED */
case Q_PIM:
bpf_error("'pim proto' is bogus");
/* NOTREACHED */
case Q_STP:
bpf_error("'stp proto' is bogus");
/* NOTREACHED */
#ifdef INET6
case Q_IPV6:
b0 = gen_linktype(ETHERTYPE_IPV6);
#ifndef CHASE_CHAIN
b1 = gen_cmp_nl(6, BPF_B, (bpf_int32)v);
#else
b1 = gen_protochain(v, Q_IPV6);
#endif
gen_and(b0, b1);
return b1;
case Q_ICMPV6:
bpf_error("'icmp6 proto' is bogus");
#endif /* INET6 */
case Q_AH:
bpf_error("'ah proto' is bogus");
case Q_ESP:
bpf_error("'esp proto' is bogus");
default:
abort();
/* NOTREACHED */
}
/* NOTREACHED */
}
struct block *
gen_scode(const char *name, struct qual q)
{
int proto = q.proto;
int dir = q.dir;
int tproto;
u_char *eaddr;
bpf_u_int32 mask, addr;
#ifndef INET6
bpf_u_int32 **alist;
#else
int tproto6;
struct sockaddr_in *sin;
struct sockaddr_in6 *sin6;
struct addrinfo *res, *res0;
struct in6_addr mask128;
#endif /*INET6*/
struct block *b, *tmp;
int port, real_proto;
switch (q.addr) {
case Q_NET:
addr = pcap_nametonetaddr(name);
if (addr == 0)
bpf_error("unknown network '%s'", name);
/* Left justify network addr and calculate its network mask */
mask = 0xffffffff;
while (addr && (addr & 0xff000000) == 0) {
addr <<= 8;
mask <<= 8;
}
return gen_host(addr, mask, proto, dir);
case Q_DEFAULT:
case Q_HOST:
if (proto == Q_LINK) {
switch (linktype) {
case DLT_EN10MB:
eaddr = pcap_ether_hostton(name);
if (eaddr == NULL)
bpf_error(
"unknown ether host '%s'", name);
return gen_ehostop(eaddr, dir);
case DLT_FDDI:
eaddr = pcap_ether_hostton(name);
if (eaddr == NULL)
bpf_error(
"unknown FDDI host '%s'", name);
return gen_fhostop(eaddr, dir);
case DLT_IEEE802_11:
case DLT_IEEE802_11_RADIO:
eaddr = pcap_ether_hostton(name);
if (eaddr == NULL)
bpf_error(
"unknown 802.11 host '%s'", name);
return gen_p80211_hostop(eaddr, dir);
default:
bpf_error(
"only ethernet/FDDI supports link-level host name");
break;
}
} else if (proto == Q_DECNET) {
unsigned short dn_addr = __pcap_nametodnaddr(name);
/*
* I don't think DECNET hosts can be multihomed, so
* there is no need to build up a list of addresses
*/
return (gen_host(dn_addr, 0, proto, dir));
} else {
#ifndef INET6
alist = pcap_nametoaddr(name);
if (alist == NULL || *alist == NULL)
bpf_error("unknown host '%s'", name);
tproto = proto;
if (off_linktype == -1 && tproto == Q_DEFAULT)
tproto = Q_IP;
b = gen_host(**alist++, 0xffffffff, tproto, dir);
while (*alist) {
tmp = gen_host(**alist++, 0xffffffff,
tproto, dir);
gen_or(b, tmp);
b = tmp;
}
return b;
#else
memset(&mask128, 0xff, sizeof(mask128));
res0 = res = pcap_nametoaddrinfo(name);
if (res == NULL)
bpf_error("unknown host '%s'", name);
b = tmp = NULL;
tproto = tproto6 = proto;
if (off_linktype == -1 && tproto == Q_DEFAULT) {
tproto = Q_IP;
tproto6 = Q_IPV6;
}
for (res = res0; res; res = res->ai_next) {
switch (res->ai_family) {
case AF_INET:
if (tproto == Q_IPV6)
continue;
sin = (struct sockaddr_in *)
res->ai_addr;
tmp = gen_host(ntohl(sin->sin_addr.s_addr),
0xffffffff, tproto, dir);
break;
case AF_INET6:
if (tproto6 == Q_IP)
continue;
sin6 = (struct sockaddr_in6 *)
res->ai_addr;
tmp = gen_host6(&sin6->sin6_addr,
&mask128, tproto6, dir);
break;
}
if (b)
gen_or(b, tmp);
b = tmp;
}
freeaddrinfo(res0);
if (b == NULL) {
bpf_error("unknown host '%s'%s", name,
(proto == Q_DEFAULT)
? ""
: " for specified address family");
}
return b;
#endif /*INET6*/
}
case Q_PORT:
if (proto != Q_DEFAULT && proto != Q_UDP && proto != Q_TCP)
bpf_error("illegal qualifier of 'port'");
if (pcap_nametoport(name, &port, &real_proto) == 0)
bpf_error("unknown port '%s'", name);
if (proto == Q_UDP) {
if (real_proto == IPPROTO_TCP)
bpf_error("port '%s' is tcp", name);
else
/* override PROTO_UNDEF */
real_proto = IPPROTO_UDP;
}
if (proto == Q_TCP) {
if (real_proto == IPPROTO_UDP)
bpf_error("port '%s' is udp", name);
else
/* override PROTO_UNDEF */
real_proto = IPPROTO_TCP;
}
#ifndef INET6
return gen_port(port, real_proto, dir);
#else
{
struct block *b;
b = gen_port(port, real_proto, dir);
gen_or(gen_port6(port, real_proto, dir), b);
return b;
}
#endif /* INET6 */
case Q_GATEWAY:
#ifndef INET6
eaddr = pcap_ether_hostton(name);
if (eaddr == NULL)
bpf_error("unknown ether host: %s", name);
alist = pcap_nametoaddr(name);
if (alist == NULL || *alist == NULL)
bpf_error("unknown host '%s'", name);
return gen_gateway(eaddr, alist, proto, dir);
#else
bpf_error("'gateway' not supported in this configuration");
#endif /*INET6*/
case Q_PROTO:
real_proto = lookup_proto(name, proto);
if (real_proto >= 0)
return gen_proto(real_proto, proto, dir);
else
bpf_error("unknown protocol: %s", name);
case Q_PROTOCHAIN:
real_proto = lookup_proto(name, proto);
if (real_proto >= 0)
return gen_protochain(real_proto, proto, dir);
else
bpf_error("unknown protocol: %s", name);
case Q_UNDEF:
syntax();
/* NOTREACHED */
}
abort();
/* NOTREACHED */
}
struct block *
gen_mcode(const char *s1, const char *s2, int masklen, struct qual q)
{
int nlen, mlen;
bpf_u_int32 n, m;
nlen = __pcap_atoin(s1, &n);
/* Promote short ipaddr */
n <<= 32 - nlen;
if (s2 != NULL) {
mlen = __pcap_atoin(s2, &m);
/* Promote short ipaddr */
m <<= 32 - mlen;
if ((n & ~m) != 0)
bpf_error("non-network bits set in \"%s mask %s\"",
s1, s2);
} else {
/* Convert mask len to mask */
if (masklen > 32)
bpf_error("mask length must be <= 32");
m = 0xffffffff << (32 - masklen);
if ((n & ~m) != 0)
bpf_error("non-network bits set in \"%s/%d\"",
s1, masklen);
}
switch (q.addr) {
case Q_NET:
return gen_host(n, m, q.proto, q.dir);
default:
bpf_error("Mask syntax for networks only");
/* NOTREACHED */
}
}
struct block *
gen_ncode(const char *s, bpf_u_int32 v, struct qual q)
{
bpf_u_int32 mask;
int proto = q.proto;
int dir = q.dir;
int vlen;
if (s == NULL)
vlen = 32;
else if (q.proto == Q_DECNET)
vlen = __pcap_atodn(s, &v);
else
vlen = __pcap_atoin(s, &v);
switch (q.addr) {
case Q_DEFAULT:
case Q_HOST:
case Q_NET:
if (proto == Q_DECNET)
return gen_host(v, 0, proto, dir);
else if (proto == Q_LINK) {
bpf_error("illegal link layer address");
} else {
mask = 0xffffffff;
if (s == NULL && q.addr == Q_NET) {
/* Promote short net number */
while (v && (v & 0xff000000) == 0) {
v <<= 8;
mask <<= 8;
}
} else {
/* Promote short ipaddr */
v <<= 32 - vlen;
mask <<= 32 - vlen;
}
return gen_host(v, mask, proto, dir);
}
case Q_PORT:
if (proto == Q_UDP)
proto = IPPROTO_UDP;
else if (proto == Q_TCP)
proto = IPPROTO_TCP;
else if (proto == Q_DEFAULT)
proto = PROTO_UNDEF;
else
bpf_error("illegal qualifier of 'port'");
#ifndef INET6
return gen_port((int)v, proto, dir);
#else
{
struct block *b;
b = gen_port((int)v, proto, dir);
gen_or(gen_port6((int)v, proto, dir), b);
return b;
}
#endif /* INET6 */
case Q_GATEWAY:
bpf_error("'gateway' requires a name");
/* NOTREACHED */
case Q_PROTO:
return gen_proto((int)v, proto, dir);
case Q_PROTOCHAIN:
return gen_protochain((int)v, proto, dir);
case Q_UNDEF:
syntax();
/* NOTREACHED */
default:
abort();
/* NOTREACHED */
}
/* NOTREACHED */
}
#ifdef INET6
struct block *
gen_mcode6(const char *s1, const char *s2, int masklen, struct qual q)
{
struct addrinfo *res;
struct in6_addr *addr;
struct in6_addr mask;
struct block *b;
u_int32_t *a, *m;
if (s2)
bpf_error("no mask %s supported", s2);
res = pcap_nametoaddrinfo(s1);
if (!res)
bpf_error("invalid ip6 address %s", s1);
if (res->ai_next)
bpf_error("%s resolved to multiple address", s1);
addr = &((struct sockaddr_in6 *)res->ai_addr)->sin6_addr;
if (sizeof(mask) * 8 < masklen)
bpf_error("mask length must be <= %u", (unsigned int)(sizeof(mask) * 8));
memset(&mask, 0, sizeof(mask));
memset(&mask, 0xff, masklen / 8);
if (masklen % 8) {
mask.s6_addr[masklen / 8] =
(0xff << (8 - masklen % 8)) & 0xff;
}
a = (u_int32_t *)addr;
m = (u_int32_t *)&mask;
if ((a[0] & ~m[0]) || (a[1] & ~m[1])
|| (a[2] & ~m[2]) || (a[3] & ~m[3])) {
bpf_error("non-network bits set in \"%s/%d\"", s1, masklen);
}
switch (q.addr) {
case Q_DEFAULT:
case Q_HOST:
if (masklen != 128)
bpf_error("Mask syntax for networks only");
/* FALLTHROUGH */
case Q_NET:
b = gen_host6(addr, &mask, q.proto, q.dir);
freeaddrinfo(res);
return b;
default:
bpf_error("invalid qualifier against IPv6 address");
/* NOTREACHED */
}
}
#endif /*INET6*/
struct block *
gen_ecode(const u_char *eaddr, struct qual q)
{
if ((q.addr == Q_HOST || q.addr == Q_DEFAULT) && q.proto == Q_LINK) {
if (linktype == DLT_EN10MB)
return gen_ehostop(eaddr, (int)q.dir);
if (linktype == DLT_FDDI)
return gen_fhostop(eaddr, (int)q.dir);
if (linktype == DLT_IEEE802_11 ||
linktype == DLT_IEEE802_11_RADIO)
return gen_p80211_hostop(eaddr, (int)q.dir);
}
bpf_error("ethernet address used in non-ether expression");
/* NOTREACHED */
}
void
sappend(struct slist *s0, struct slist *s1)
{
/*
* This is definitely not the best way to do this, but the
* lists will rarely get long.
*/
while (s0->next)
s0 = s0->next;
s0->next = s1;
}
static struct slist *
xfer_to_x(struct arth *a)
{
struct slist *s;
s = new_stmt(BPF_LDX|BPF_MEM);
s->s.k = a->regno;
return s;
}
static struct slist *
xfer_to_a(struct arth *a)
{
struct slist *s;
s = new_stmt(BPF_LD|BPF_MEM);
s->s.k = a->regno;
return s;
}
struct arth *
gen_load(int proto, struct arth *index, int size)
{
struct slist *s, *tmp;
struct block *b;
int regno = alloc_reg();
free_reg(index->regno);
switch (size) {
default:
bpf_error("data size must be 1, 2, or 4");
case 1:
size = BPF_B;
break;
case 2:
size = BPF_H;
break;
case 4:
size = BPF_W;
break;
}
switch (proto) {
default:
bpf_error("unsupported index operation");
case Q_LINK:
s = xfer_to_x(index);
tmp = new_stmt(BPF_LD|BPF_IND|size);
sappend(s, tmp);
sappend(index->s, s);
break;
case Q_IP:
case Q_ARP:
case Q_RARP:
case Q_ATALK:
case Q_DECNET:
case Q_SCA:
case Q_LAT:
case Q_MOPRC:
case Q_MOPDL:
#ifdef INET6
case Q_IPV6:
#endif
/* XXX Note that we assume a fixed link header here. */
if (variable_nl) {
s = nl2X_stmt();
sappend(s, xfer_to_a(index));
sappend(s, new_stmt(BPF_ALU|BPF_ADD|BPF_X));
sappend(s, new_stmt(BPF_MISC|BPF_TAX));
} else {
s = xfer_to_x(index);
}
tmp = new_stmt(BPF_LD|BPF_IND|size);
tmp->s.k = off_nl; /* off_nl == 0 for variable_nl */
sappend(s, tmp);
sappend(index->s, s);
b = gen_proto_abbrev(proto);
if (index->b)
gen_and(index->b, b);
index->b = b;
break;
case Q_TCP:
case Q_UDP:
case Q_ICMP:
case Q_IGMP:
case Q_IGRP:
case Q_PIM:
s = iphl_to_x();
sappend(s, xfer_to_a(index));
sappend(s, new_stmt(BPF_ALU|BPF_ADD|BPF_X));
sappend(s, new_stmt(BPF_MISC|BPF_TAX));
sappend(s, tmp = new_stmt(BPF_LD|BPF_IND|size));
tmp->s.k = off_nl; /* off_nl is 0 if variable_nl */
sappend(index->s, s);
gen_and(gen_proto_abbrev(proto), b = gen_ipfrag());
if (index->b)
gen_and(index->b, b);
#ifdef INET6
gen_and(gen_proto_abbrev(Q_IP), b);
#endif
index->b = b;
break;
#ifdef INET6
case Q_ICMPV6:
bpf_error("IPv6 upper-layer protocol is not supported by proto[x]");
/*NOTREACHED*/
#endif
}
index->regno = regno;
s = new_stmt(BPF_ST);
s->s.k = regno;
sappend(index->s, s);
return index;
}
struct block *
gen_relation(int code, struct arth *a0, struct arth *a1, int reversed)
{
struct slist *s0, *s1, *s2;
struct block *b, *tmp;
s0 = xfer_to_x(a1);
s1 = xfer_to_a(a0);
s2 = new_stmt(BPF_ALU|BPF_SUB|BPF_X);
b = new_block(JMP(code));
if (code == BPF_JGT || code == BPF_JGE) {
reversed = !reversed;
b->s.k = 0x80000000;
}
if (reversed)
gen_not(b);
sappend(s1, s2);
sappend(s0, s1);
sappend(a1->s, s0);
sappend(a0->s, a1->s);
b->stmts = a0->s;
free_reg(a0->regno);
free_reg(a1->regno);
/* 'and' together protocol checks */
if (a0->b) {
if (a1->b) {
gen_and(a0->b, tmp = a1->b);
}
else
tmp = a0->b;
} else
tmp = a1->b;
if (tmp)
gen_and(tmp, b);
return b;
}
struct arth *
gen_loadlen(void)
{
int regno = alloc_reg();
struct arth *a = (struct arth *)newchunk(sizeof(*a));
struct slist *s;
s = new_stmt(BPF_LD|BPF_LEN);
s->next = new_stmt(BPF_ST);
s->next->s.k = regno;
a->s = s;
a->regno = regno;
return a;
}
struct arth *
gen_loadrnd(void)
{
int regno = alloc_reg();
struct arth *a = (struct arth *)newchunk(sizeof(*a));
struct slist *s;
s = new_stmt(BPF_LD|BPF_RND);
s->next = new_stmt(BPF_ST);
s->next->s.k = regno;
a->s = s;
a->regno = regno;
return a;
}
struct arth *
gen_loadi(int val)
{
struct arth *a;
struct slist *s;
int reg;
a = (struct arth *)newchunk(sizeof(*a));
reg = alloc_reg();
s = new_stmt(BPF_LD|BPF_IMM);
s->s.k = val;
s->next = new_stmt(BPF_ST);
s->next->s.k = reg;
a->s = s;
a->regno = reg;
return a;
}
struct arth *
gen_neg(struct arth *a)
{
struct slist *s;
s = xfer_to_a(a);
sappend(a->s, s);
s = new_stmt(BPF_ALU|BPF_NEG);
s->s.k = 0;
sappend(a->s, s);
s = new_stmt(BPF_ST);
s->s.k = a->regno;
sappend(a->s, s);
return a;
}
struct arth *
gen_arth(int code, struct arth *a0, struct arth *a1)
{
struct slist *s0, *s1, *s2;
s0 = xfer_to_x(a1);
s1 = xfer_to_a(a0);
s2 = new_stmt(BPF_ALU|BPF_X|code);
sappend(s1, s2);
sappend(s0, s1);
sappend(a1->s, s0);
sappend(a0->s, a1->s);
free_reg(a1->regno);
s0 = new_stmt(BPF_ST);
a0->regno = s0->s.k = alloc_reg();
sappend(a0->s, s0);
return a0;
}
/*
* Here we handle simple allocation of the scratch registers.
* If too many registers are alloc'd, the allocator punts.
*/
static int regused[BPF_MEMWORDS];
static int curreg;
/*
* Return the next free register.
*/
static int
alloc_reg(void)
{
int n = BPF_MEMWORDS;
while (--n >= 0) {
if (regused[curreg])
curreg = (curreg + 1) % BPF_MEMWORDS;
else {
regused[curreg] = 1;
return curreg;
}
}
bpf_error("too many registers needed to evaluate expression");
/* NOTREACHED */
}
/*
* Return a register to the table so it can
* be used later.
*/
static void
free_reg(int n)
{
regused[n] = 0;
}
static struct block *
gen_len(int jmp, int n)
{
struct slist *s;
struct block *b;
s = new_stmt(BPF_LD|BPF_LEN);
b = new_block(JMP(jmp));
b->stmts = s;
b->s.k = n;
return b;
}
struct block *
gen_greater(int n)
{
return gen_len(BPF_JGE, n);
}
struct block *
gen_less(int n)
{
struct block *b;
b = gen_len(BPF_JGT, n);
gen_not(b);
return b;
}
struct block *
gen_byteop(int op, int idx, int val)
{
struct block *b;
struct slist *s;
switch (op) {
default:
abort();
case '=':
return gen_cmp((u_int)idx, BPF_B, (bpf_int32)val);
case '<':
b = gen_cmp((u_int)idx, BPF_B, (bpf_int32)val);
b->s.code = JMP(BPF_JGE);
gen_not(b);
return b;
case '>':
b = gen_cmp((u_int)idx, BPF_B, (bpf_int32)val);
b->s.code = JMP(BPF_JGT);
return b;
case '|':
s = new_stmt(BPF_ALU|BPF_OR|BPF_K);
break;
case '&':
s = new_stmt(BPF_ALU|BPF_AND|BPF_K);
break;
}
s->s.k = val;
b = new_block(JMP(BPF_JEQ));
b->stmts = s;
gen_not(b);
return b;
}
struct block *
gen_broadcast(int proto)
{
bpf_u_int32 hostmask;
struct block *b0, *b1, *b2;
static u_char ebroadcast[] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
switch (proto) {
case Q_DEFAULT:
case Q_LINK:
if (linktype == DLT_EN10MB)
return gen_ehostop(ebroadcast, Q_DST);
if (linktype == DLT_FDDI)
return gen_fhostop(ebroadcast, Q_DST);
if (linktype == DLT_IEEE802_11 ||
linktype == DLT_IEEE802_11_RADIO)
return gen_p80211_hostop(ebroadcast, Q_DST);
bpf_error("not a broadcast link");
break;
case Q_IP:
/*
* We treat a netmask of PCAP_NETMASK_UNKNOWN (0xffffffff)
* as an indication that we don't know the netmask, and fail
* in that case.
*/
if (netmask == PCAP_NETMASK_UNKNOWN)
bpf_error("netmask not known, so 'ip broadcast' not supported");
b0 = gen_linktype(ETHERTYPE_IP);
hostmask = ~netmask;
b1 = gen_mcmp_nl(16, BPF_W, (bpf_int32)0, hostmask);
b2 = gen_mcmp_nl(16, BPF_W,
(bpf_int32)(~0 & hostmask), hostmask);
gen_or(b1, b2);
gen_and(b0, b2);
return b2;
}
bpf_error("only ether/ip broadcast filters supported");
}
struct block *
gen_multicast(int proto)
{
struct block *b0, *b1;
struct slist *s;
switch (proto) {
case Q_DEFAULT:
case Q_LINK:
if (linktype == DLT_EN10MB) {
/* ether[0] & 1 != 0 */
s = new_stmt(BPF_LD|BPF_B|BPF_ABS);
s->s.k = 0;
b0 = new_block(JMP(BPF_JSET));
b0->s.k = 1;
b0->stmts = s;
return b0;
}
if (linktype == DLT_FDDI) {
/* XXX TEST THIS: MIGHT NOT PORT PROPERLY XXX */
/* fddi[1] & 1 != 0 */
s = new_stmt(BPF_LD|BPF_B|BPF_ABS);
s->s.k = 1;
b0 = new_block(JMP(BPF_JSET));
b0->s.k = 1;
b0->stmts = s;
return b0;
}
/* Link not known to support multicasts */
break;
case Q_IP:
b0 = gen_linktype(ETHERTYPE_IP);
b1 = gen_cmp_nl(16, BPF_B, (bpf_int32)224);
b1->s.code = JMP(BPF_JGE);
gen_and(b0, b1);
return b1;
#ifdef INET6
case Q_IPV6:
b0 = gen_linktype(ETHERTYPE_IPV6);
b1 = gen_cmp_nl(24, BPF_B, (bpf_int32)255);
gen_and(b0, b1);
return b1;
#endif /* INET6 */
}
bpf_error("only IP multicast filters supported on ethernet/FDDI");
}
/*
* generate command for inbound/outbound. It's here so we can
* make it link-type specific. 'dir' = 0 implies "inbound",
* = 1 implies "outbound".
*/
struct block *
gen_inbound(int dir)
{
struct block *b0;
/*
* Only SLIP and old-style PPP data link types support
* inbound/outbound qualifiers.
*/
switch (linktype) {
case DLT_SLIP:
case DLT_PPP:
b0 = gen_relation(BPF_JEQ,
gen_load(Q_LINK, gen_loadi(0), 1),
gen_loadi(0),
dir);
break;
case DLT_PFLOG:
b0 = gen_cmp(offsetof(struct pfloghdr, dir), BPF_B,
(bpf_int32)((dir == 0) ? PF_IN : PF_OUT));
break;
default:
bpf_error("inbound/outbound not supported on linktype 0x%x",
linktype);
/* NOTREACHED */
}
return (b0);
}
/* PF firewall log matched interface */
struct block *
gen_pf_ifname(char *ifname)
{
struct block *b0;
u_int len, off;
if (linktype == DLT_PFLOG) {
len = sizeof(((struct pfloghdr *)0)->ifname);
off = offsetof(struct pfloghdr, ifname);
} else {
bpf_error("ifname not supported on linktype 0x%x", linktype);
/* NOTREACHED */
}
if (strlen(ifname) >= len) {
bpf_error("ifname interface names can only be %d characters",
len - 1);
/* NOTREACHED */
}
b0 = gen_bcmp(off, strlen(ifname) + 1, ifname);
return (b0);
}
/* PF firewall log ruleset name */
struct block *
gen_pf_ruleset(char *ruleset)
{
struct block *b0;
if (linktype != DLT_PFLOG) {
bpf_error("ruleset not supported on linktype 0x%x", linktype);
/* NOTREACHED */
}
if (strlen(ruleset) >= sizeof(((struct pfloghdr *)0)->ruleset)) {
bpf_error("ruleset names can only be %zu characters",
sizeof(((struct pfloghdr *)0)->ruleset) - 1);
/* NOTREACHED */
}
b0 = gen_bcmp(offsetof(struct pfloghdr, ruleset),
strlen(ruleset), ruleset);
return (b0);
}
/* PF firewall log rule number */
struct block *
gen_pf_rnr(int rnr)
{
struct block *b0;
if (linktype == DLT_PFLOG) {
b0 = gen_cmp(offsetof(struct pfloghdr, rulenr), BPF_W,
(bpf_int32)rnr);
} else {
bpf_error("rnr not supported on linktype 0x%x", linktype);
/* NOTREACHED */
}
return (b0);
}
/* PF firewall log sub-rule number */
struct block *
gen_pf_srnr(int srnr)
{
struct block *b0;
if (linktype != DLT_PFLOG) {
bpf_error("srnr not supported on linktype 0x%x", linktype);
/* NOTREACHED */
}
b0 = gen_cmp(offsetof(struct pfloghdr, subrulenr), BPF_W,
(bpf_int32)srnr);
return (b0);
}
/* PF firewall log reason code */
struct block *
gen_pf_reason(int reason)
{
struct block *b0;
if (linktype == DLT_PFLOG) {
b0 = gen_cmp(offsetof(struct pfloghdr, reason), BPF_B,
(bpf_int32)reason);
} else {
bpf_error("reason not supported on linktype 0x%x", linktype);
/* NOTREACHED */
}
return (b0);
}
/* PF firewall log action */
struct block *
gen_pf_action(int action)
{
struct block *b0;
if (linktype == DLT_PFLOG) {
b0 = gen_cmp(offsetof(struct pfloghdr, action), BPF_B,
(bpf_int32)action);
} else {
bpf_error("action not supported on linktype 0x%x", linktype);
/* NOTREACHED */
}
return (b0);
}
/* IEEE 802.11 wireless header */
struct block *
gen_p80211_type(int type, int mask)
{
struct block *b0;
u_int offset;
if (!(linktype == DLT_IEEE802_11 ||
linktype == DLT_IEEE802_11_RADIO)) {
bpf_error("type not supported on linktype 0x%x",
linktype);
/* NOTREACHED */
}
offset = (u_int)offsetof(struct ieee80211_frame, i_fc[0]);
if (linktype == DLT_IEEE802_11_RADIO)
offset += IEEE80211_RADIOTAP_HDRLEN;
b0 = gen_mcmp(offset, BPF_B, (bpf_int32)type, (bpf_u_int32)mask);
return (b0);
}
static struct block *
gen_ahostop(const u_char *eaddr, int dir)
{
struct block *b0, *b1;
switch (dir) {
/* src comes first, different from Ethernet */
case Q_SRC:
return gen_bcmp(0, 1, eaddr);
case Q_DST:
return gen_bcmp(1, 1, eaddr);
case Q_AND:
b0 = gen_ahostop(eaddr, Q_SRC);
b1 = gen_ahostop(eaddr, Q_DST);
gen_and(b0, b1);
return b1;
case Q_DEFAULT:
case Q_OR:
b0 = gen_ahostop(eaddr, Q_SRC);
b1 = gen_ahostop(eaddr, Q_DST);
gen_or(b0, b1);
return b1;
}
abort();
/* NOTREACHED */
}
struct block *
gen_acode(const u_char *eaddr, struct qual q)
{
if ((q.addr == Q_HOST || q.addr == Q_DEFAULT) && q.proto == Q_LINK) {
if (linktype == DLT_ARCNET)
return gen_ahostop(eaddr, (int)q.dir);
}
bpf_error("ARCnet address used in non-arc expression");
/* NOTREACHED */
}
struct block *
gen_mpls(int label)
{
struct block *b0;
if (label > MPLS_LABEL_MAX)
bpf_error("invalid MPLS label : %d", label);
if (mpls_stack > 0) /* Bottom-Of-Label-Stack bit ? */
b0 = gen_mcmp(off_nl-2, BPF_B, (bpf_int32)0, 0x1);
else
b0 = gen_linktype(ETHERTYPE_MPLS);
if (label >= 0) {
struct block *b1;
b1 = gen_mcmp(off_nl, BPF_W, (bpf_int32)(label << 12),
MPLS_LABEL_MASK);
gen_and(b0, b1);
b0 = b1;
}
off_nl += 4;
off_linktype += 4;
mpls_stack++;
return (b0);
}
/*
* support IEEE 802.1Q VLAN trunk over ethernet
*/
struct block *
gen_vlan(int vlan_num)
{
struct block *b0;
if (variable_nl) {
bpf_error("'vlan' not supported for variable DLTs");
/*NOTREACHED*/
}
if (vlan_num > 4095) {
bpf_error("invalid VLAN number : %d", vlan_num);
/*NOTREACHED*/
}
/*
* Change the offsets to point to the type and data fields within
* the VLAN packet. This is somewhat of a kludge.
*/
if (orig_nl == (u_int)-1) {
orig_linktype = off_linktype; /* save original values */
orig_nl = off_nl;
orig_nl_nosnap = off_nl_nosnap;
switch (linktype) {
case DLT_EN10MB:
off_linktype = 16;
off_nl_nosnap = 18;
off_nl = 18;
break;
default:
bpf_error("no VLAN support for data link type %d",
linktype);
/*NOTREACHED*/
}
}
/* check for VLAN */
b0 = gen_cmp(orig_linktype, BPF_H, (bpf_int32)ETHERTYPE_8021Q);
/* If a specific VLAN is requested, check VLAN id */
if (vlan_num >= 0) {
struct block *b1;
b1 = gen_mcmp(orig_nl, BPF_H, (bpf_int32)vlan_num, 0x0FFF);
gen_and(b0, b1);
b0 = b1;
}
return (b0);
}
struct block *
gen_sample(int rate)
{
struct block *b0;
long long threshold = 0x100000000LL; /* 0xffffffff + 1 */
if (rate < 2) {
bpf_error("sample %d is too low", rate);
/*NOTREACHED*/
}
if (rate > (1 << 20)) {
bpf_error("sample %d is too high", rate);
/*NOTREACHED*/
}
threshold /= rate;
b0 = gen_relation(BPF_JGT, gen_loadrnd(), gen_loadi(threshold), 1);
return (b0);
}
struct block *
gen_p80211_fcdir(int fcdir)
{
struct block *b0;
u_int offset;
if (!(linktype == DLT_IEEE802_11 ||
linktype == DLT_IEEE802_11_RADIO)) {
bpf_error("frame direction not supported on linktype 0x%x",
linktype);
/* NOTREACHED */
}
offset = (u_int)offsetof(struct ieee80211_frame, i_fc[1]);
if (linktype == DLT_IEEE802_11_RADIO)
offset += IEEE80211_RADIOTAP_HDRLEN;
b0 = gen_mcmp(offset, BPF_B, (bpf_int32)fcdir,
(bpf_u_int32)IEEE80211_FC1_DIR_MASK);
return (b0);
}
static struct block *
gen_p80211_hostop(const u_char *lladdr, int dir)
{
struct block *b0, *b1, *b2, *b3, *b4;
u_int offset = 0;
if (linktype == DLT_IEEE802_11_RADIO)
offset = IEEE80211_RADIOTAP_HDRLEN;
switch (dir) {
case Q_SRC:
b0 = gen_p80211_addr(IEEE80211_FC1_DIR_NODS, offset +
(u_int)offsetof(struct ieee80211_frame, i_addr2),
lladdr);
b1 = gen_p80211_addr(IEEE80211_FC1_DIR_TODS, offset +
(u_int)offsetof(struct ieee80211_frame, i_addr2),
lladdr);
b2 = gen_p80211_addr(IEEE80211_FC1_DIR_FROMDS, offset +
(u_int)offsetof(struct ieee80211_frame, i_addr3),
lladdr);
b3 = gen_p80211_addr(IEEE80211_FC1_DIR_DSTODS, offset +
(u_int)offsetof(struct ieee80211_frame_addr4, i_addr4),
lladdr);
b4 = gen_p80211_addr(IEEE80211_FC1_DIR_DSTODS, offset +
(u_int)offsetof(struct ieee80211_frame_addr4, i_addr2),
lladdr);
gen_or(b0, b1);
gen_or(b1, b2);
gen_or(b2, b3);
gen_or(b3, b4);
return (b4);
case Q_DST:
b0 = gen_p80211_addr(IEEE80211_FC1_DIR_NODS, offset +
(u_int)offsetof(struct ieee80211_frame, i_addr1),
lladdr);
b1 = gen_p80211_addr(IEEE80211_FC1_DIR_TODS, offset +
(u_int)offsetof(struct ieee80211_frame, i_addr3),
lladdr);
b2 = gen_p80211_addr(IEEE80211_FC1_DIR_FROMDS, offset +
(u_int)offsetof(struct ieee80211_frame, i_addr1),
lladdr);
b3 = gen_p80211_addr(IEEE80211_FC1_DIR_DSTODS, offset +
(u_int)offsetof(struct ieee80211_frame_addr4, i_addr3),
lladdr);
b4 = gen_p80211_addr(IEEE80211_FC1_DIR_DSTODS, offset +
(u_int)offsetof(struct ieee80211_frame_addr4, i_addr1),
lladdr);
gen_or(b0, b1);
gen_or(b1, b2);
gen_or(b2, b3);
gen_or(b3, b4);
return (b4);
case Q_ADDR1:
return (gen_bcmp(offset +
(u_int)offsetof(struct ieee80211_frame,
i_addr1), IEEE80211_ADDR_LEN, lladdr));
case Q_ADDR2:
return (gen_bcmp(offset +
(u_int)offsetof(struct ieee80211_frame,
i_addr2), IEEE80211_ADDR_LEN, lladdr));
case Q_ADDR3:
return (gen_bcmp(offset +
(u_int)offsetof(struct ieee80211_frame,
i_addr3), IEEE80211_ADDR_LEN, lladdr));
case Q_ADDR4:
return (gen_p80211_addr(IEEE80211_FC1_DIR_DSTODS, offset +
(u_int)offsetof(struct ieee80211_frame_addr4, i_addr4),
lladdr));
case Q_AND:
b0 = gen_p80211_hostop(lladdr, Q_SRC);
b1 = gen_p80211_hostop(lladdr, Q_DST);
gen_and(b0, b1);
return (b1);
case Q_DEFAULT:
case Q_OR:
b0 = gen_p80211_hostop(lladdr, Q_ADDR1);
b1 = gen_p80211_hostop(lladdr, Q_ADDR2);
b2 = gen_p80211_hostop(lladdr, Q_ADDR3);
b3 = gen_p80211_hostop(lladdr, Q_ADDR4);
gen_or(b0, b1);
gen_or(b1, b2);
gen_or(b2, b3);
return (b3);
default:
bpf_error("direction not supported on linktype 0x%x",
linktype);
}
/* NOTREACHED */
}
static struct block *
gen_p80211_addr(int fcdir, u_int offset, const u_char *lladdr)
{
struct block *b0, *b1;
b0 = gen_mcmp(offset, BPF_B, (bpf_int32)fcdir, IEEE80211_FC1_DIR_MASK);
b1 = gen_bcmp(offset, IEEE80211_ADDR_LEN, lladdr);
gen_and(b0, b1);
return (b1);
}
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