/* Library which manipulates firewall rules. Version 0.1. */
/* Architecture of firewall rules is as follows:
*
* Chains go INPUT, FORWARD, OUTPUT then user chains.
* Each user chain starts with an ERROR node.
* Every chain ends with an unconditional jump: a RETURN for user chains,
* and a POLICY for built-ins.
*/
/* (C)1999 Paul ``Rusty'' Russell - Placed under the GNU GPL (See
COPYING for details). */
#include <assert.h>
#include <string.h>
#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <arpa/inet.h>
#ifdef DEBUG_CONNTRACK
#define inline
#endif
#if !defined(__ANDROID__) && (!defined(__GLIBC__) || (__GLIBC__ < 2))
typedef unsigned int socklen_t;
#endif
#include "libiptc/libip6tc.h"
#define HOOK_PRE_ROUTING NF_IP6_PRE_ROUTING
#define HOOK_LOCAL_IN NF_IP6_LOCAL_IN
#define HOOK_FORWARD NF_IP6_FORWARD
#define HOOK_LOCAL_OUT NF_IP6_LOCAL_OUT
#define HOOK_POST_ROUTING NF_IP6_POST_ROUTING
#define STRUCT_ENTRY_TARGET struct xt_entry_target
#define STRUCT_ENTRY struct ip6t_entry
#define STRUCT_ENTRY_MATCH struct xt_entry_match
#define STRUCT_GETINFO struct ip6t_getinfo
#define STRUCT_GET_ENTRIES struct ip6t_get_entries
#define STRUCT_COUNTERS struct xt_counters
#define STRUCT_COUNTERS_INFO struct xt_counters_info
#define STRUCT_STANDARD_TARGET struct xt_standard_target
#define STRUCT_REPLACE struct ip6t_replace
#define ENTRY_ITERATE IP6T_ENTRY_ITERATE
#define TABLE_MAXNAMELEN XT_TABLE_MAXNAMELEN
#define FUNCTION_MAXNAMELEN XT_FUNCTION_MAXNAMELEN
#define GET_TARGET ip6t_get_target
#define ERROR_TARGET XT_ERROR_TARGET
#define NUMHOOKS NF_IP6_NUMHOOKS
#define IPT_CHAINLABEL xt_chainlabel
#define TC_DUMP_ENTRIES dump_entries6
#define TC_IS_CHAIN ip6tc_is_chain
#define TC_FIRST_CHAIN ip6tc_first_chain
#define TC_NEXT_CHAIN ip6tc_next_chain
#define TC_FIRST_RULE ip6tc_first_rule
#define TC_NEXT_RULE ip6tc_next_rule
#define TC_GET_TARGET ip6tc_get_target
#define TC_BUILTIN ip6tc_builtin
#define TC_GET_POLICY ip6tc_get_policy
#define TC_INSERT_ENTRY ip6tc_insert_entry
#define TC_REPLACE_ENTRY ip6tc_replace_entry
#define TC_APPEND_ENTRY ip6tc_append_entry
#define TC_CHECK_ENTRY ip6tc_check_entry
#define TC_DELETE_ENTRY ip6tc_delete_entry
#define TC_DELETE_NUM_ENTRY ip6tc_delete_num_entry
#define TC_FLUSH_ENTRIES ip6tc_flush_entries
#define TC_ZERO_ENTRIES ip6tc_zero_entries
#define TC_ZERO_COUNTER ip6tc_zero_counter
#define TC_READ_COUNTER ip6tc_read_counter
#define TC_SET_COUNTER ip6tc_set_counter
#define TC_CREATE_CHAIN ip6tc_create_chain
#define TC_GET_REFERENCES ip6tc_get_references
#define TC_DELETE_CHAIN ip6tc_delete_chain
#define TC_RENAME_CHAIN ip6tc_rename_chain
#define TC_SET_POLICY ip6tc_set_policy
#define TC_GET_RAW_SOCKET ip6tc_get_raw_socket
#define TC_INIT ip6tc_init
#define TC_FREE ip6tc_free
#define TC_COMMIT ip6tc_commit
#define TC_STRERROR ip6tc_strerror
#define TC_NUM_RULES ip6tc_num_rules
#define TC_GET_RULE ip6tc_get_rule
#define TC_OPS ip6tc_ops
#define TC_AF AF_INET6
#define TC_IPPROTO IPPROTO_IPV6
#define SO_SET_REPLACE IP6T_SO_SET_REPLACE
#define SO_SET_ADD_COUNTERS IP6T_SO_SET_ADD_COUNTERS
#define SO_GET_INFO IP6T_SO_GET_INFO
#define SO_GET_ENTRIES IP6T_SO_GET_ENTRIES
#define SO_GET_VERSION IP6T_SO_GET_VERSION
#define STANDARD_TARGET XT_STANDARD_TARGET
#define LABEL_RETURN IP6TC_LABEL_RETURN
#define LABEL_ACCEPT IP6TC_LABEL_ACCEPT
#define LABEL_DROP IP6TC_LABEL_DROP
#define LABEL_QUEUE IP6TC_LABEL_QUEUE
#define ALIGN XT_ALIGN
#define RETURN XT_RETURN
#include "libiptc.c"
#define BIT6(a, l) \
((ntohl(a->s6_addr32[(l) / 32]) >> (31 - ((l) & 31))) & 1)
static int
ipv6_prefix_length(const struct in6_addr *a)
{
int l, i;
for (l = 0; l < 128; l++) {
if (BIT6(a, l) == 0)
break;
}
for (i = l + 1; i < 128; i++) {
if (BIT6(a, i) == 1)
return -1;
}
return l;
}
static int
dump_entry(struct ip6t_entry *e, struct xtc_handle *const handle)
{
size_t i;
char buf[40];
int len;
struct xt_entry_target *t;
printf("Entry %u (%lu):\n", iptcb_entry2index(handle, e),
iptcb_entry2offset(handle, e));
puts("SRC IP: ");
inet_ntop(AF_INET6, &e->ipv6.src, buf, sizeof buf);
puts(buf);
putchar('/');
len = ipv6_prefix_length(&e->ipv6.smsk);
if (len != -1)
printf("%d", len);
else {
inet_ntop(AF_INET6, &e->ipv6.smsk, buf, sizeof buf);
puts(buf);
}
putchar('\n');
puts("DST IP: ");
inet_ntop(AF_INET6, &e->ipv6.dst, buf, sizeof buf);
puts(buf);
putchar('/');
len = ipv6_prefix_length(&e->ipv6.dmsk);
if (len != -1)
printf("%d", len);
else {
inet_ntop(AF_INET6, &e->ipv6.dmsk, buf, sizeof buf);
puts(buf);
}
putchar('\n');
printf("Interface: `%s'/", e->ipv6.iniface);
for (i = 0; i < IFNAMSIZ; i++)
printf("%c", e->ipv6.iniface_mask[i] ? 'X' : '.');
printf("to `%s'/", e->ipv6.outiface);
for (i = 0; i < IFNAMSIZ; i++)
printf("%c", e->ipv6.outiface_mask[i] ? 'X' : '.');
printf("\nProtocol: %u\n", e->ipv6.proto);
if (e->ipv6.flags & IP6T_F_TOS)
printf("TOS: %u\n", e->ipv6.tos);
printf("Flags: %02X\n", e->ipv6.flags);
printf("Invflags: %02X\n", e->ipv6.invflags);
printf("Counters: %llu packets, %llu bytes\n",
(unsigned long long)e->counters.pcnt, (unsigned long long)e->counters.bcnt);
printf("Cache: %08X\n", e->nfcache);
IP6T_MATCH_ITERATE(e, print_match);
t = ip6t_get_target(e);
printf("Target name: `%s' [%u]\n", t->u.user.name, t->u.target_size);
if (strcmp(t->u.user.name, XT_STANDARD_TARGET) == 0) {
const unsigned char *data = t->data;
int pos = *(const int *)data;
if (pos < 0)
printf("verdict=%s\n",
pos == -NF_ACCEPT-1 ? "NF_ACCEPT"
: pos == -NF_DROP-1 ? "NF_DROP"
: pos == XT_RETURN ? "RETURN"
: "UNKNOWN");
else
printf("verdict=%u\n", pos);
} else if (strcmp(t->u.user.name, XT_ERROR_TARGET) == 0)
printf("error=`%s'\n", t->data);
printf("\n");
return 0;
}
static unsigned char *
is_same(const STRUCT_ENTRY *a, const STRUCT_ENTRY *b,
unsigned char *matchmask)
{
unsigned int i;
unsigned char *mptr;
/* Always compare head structures: ignore mask here. */
if (memcmp(&a->ipv6.src, &b->ipv6.src, sizeof(struct in6_addr))
|| memcmp(&a->ipv6.dst, &b->ipv6.dst, sizeof(struct in6_addr))
|| memcmp(&a->ipv6.smsk, &b->ipv6.smsk, sizeof(struct in6_addr))
|| memcmp(&a->ipv6.dmsk, &b->ipv6.dmsk, sizeof(struct in6_addr))
|| a->ipv6.proto != b->ipv6.proto
|| a->ipv6.tos != b->ipv6.tos
|| a->ipv6.flags != b->ipv6.flags
|| a->ipv6.invflags != b->ipv6.invflags)
return NULL;
for (i = 0; i < IFNAMSIZ; i++) {
if (a->ipv6.iniface_mask[i] != b->ipv6.iniface_mask[i])
return NULL;
if ((a->ipv6.iniface[i] & a->ipv6.iniface_mask[i])
!= (b->ipv6.iniface[i] & b->ipv6.iniface_mask[i]))
return NULL;
if (a->ipv6.outiface_mask[i] != b->ipv6.outiface_mask[i])
return NULL;
if ((a->ipv6.outiface[i] & a->ipv6.outiface_mask[i])
!= (b->ipv6.outiface[i] & b->ipv6.outiface_mask[i]))
return NULL;
}
if (a->target_offset != b->target_offset
|| a->next_offset != b->next_offset)
return NULL;
mptr = matchmask + sizeof(STRUCT_ENTRY);
if (IP6T_MATCH_ITERATE(a, match_different, a->elems, b->elems, &mptr))
return NULL;
mptr += XT_ALIGN(sizeof(struct xt_entry_target));
return mptr;
}
/* All zeroes == unconditional rule. */
static inline int
unconditional(const struct ip6t_ip6 *ipv6)
{
unsigned int i;
for (i = 0; i < sizeof(*ipv6); i++)
if (((char *)ipv6)[i])
break;
return (i == sizeof(*ipv6));
}
#ifdef IPTC_DEBUG
/* Do every conceivable sanity check on the handle */
static void
do_check(struct xtc_handle *h, unsigned int line)
{
unsigned int i, n;
unsigned int user_offset; /* Offset of first user chain */
int was_return;
assert(h->changed == 0 || h->changed == 1);
if (strcmp(h->info.name, "filter") == 0) {
assert(h->info.valid_hooks
== (1 << NF_IP6_LOCAL_IN
| 1 << NF_IP6_FORWARD
| 1 << NF_IP6_LOCAL_OUT));
/* Hooks should be first three */
assert(h->info.hook_entry[NF_IP6_LOCAL_IN] == 0);
n = get_chain_end(h, 0);
n += get_entry(h, n)->next_offset;
assert(h->info.hook_entry[NF_IP6_FORWARD] == n);
n = get_chain_end(h, n);
n += get_entry(h, n)->next_offset;
assert(h->info.hook_entry[NF_IP6_LOCAL_OUT] == n);
user_offset = h->info.hook_entry[NF_IP6_LOCAL_OUT];
} else if (strcmp(h->info.name, "nat") == 0) {
assert((h->info.valid_hooks
== (1 << NF_IP6_PRE_ROUTING
| 1 << NF_IP6_LOCAL_OUT
| 1 << NF_IP6_POST_ROUTING)) ||
(h->info.valid_hooks
== (1 << NF_IP6_PRE_ROUTING
| 1 << NF_IP6_LOCAL_IN
| 1 << NF_IP6_LOCAL_OUT
| 1 << NF_IP6_POST_ROUTING)));
assert(h->info.hook_entry[NF_IP6_PRE_ROUTING] == 0);
n = get_chain_end(h, 0);
n += get_entry(h, n)->next_offset;
assert(h->info.hook_entry[NF_IP6_POST_ROUTING] == n);
n = get_chain_end(h, n);
n += get_entry(h, n)->next_offset;
assert(h->info.hook_entry[NF_IP6_LOCAL_OUT] == n);
user_offset = h->info.hook_entry[NF_IP6_LOCAL_OUT];
if (h->info.valid_hooks & (1 << NF_IP6_LOCAL_IN)) {
n = get_chain_end(h, n);
n += get_entry(h, n)->next_offset;
assert(h->info.hook_entry[NF_IP6_LOCAL_IN] == n);
user_offset = h->info.hook_entry[NF_IP6_LOCAL_IN];
}
} else if (strcmp(h->info.name, "mangle") == 0) {
/* This code is getting ugly because linux < 2.4.18-pre6 had
* two mangle hooks, linux >= 2.4.18-pre6 has five mangle hooks
* */
assert((h->info.valid_hooks
== (1 << NF_IP6_PRE_ROUTING
| 1 << NF_IP6_LOCAL_OUT)) ||
(h->info.valid_hooks
== (1 << NF_IP6_PRE_ROUTING
| 1 << NF_IP6_LOCAL_IN
| 1 << NF_IP6_FORWARD
| 1 << NF_IP6_LOCAL_OUT
| 1 << NF_IP6_POST_ROUTING)));
/* Hooks should be first five */
assert(h->info.hook_entry[NF_IP6_PRE_ROUTING] == 0);
n = get_chain_end(h, 0);
if (h->info.valid_hooks & (1 << NF_IP6_LOCAL_IN)) {
n += get_entry(h, n)->next_offset;
assert(h->info.hook_entry[NF_IP6_LOCAL_IN] == n);
n = get_chain_end(h, n);
}
if (h->info.valid_hooks & (1 << NF_IP6_FORWARD)) {
n += get_entry(h, n)->next_offset;
assert(h->info.hook_entry[NF_IP6_FORWARD] == n);
n = get_chain_end(h, n);
}
n += get_entry(h, n)->next_offset;
assert(h->info.hook_entry[NF_IP6_LOCAL_OUT] == n);
user_offset = h->info.hook_entry[NF_IP6_LOCAL_OUT];
if (h->info.valid_hooks & (1 << NF_IP6_POST_ROUTING)) {
n = get_chain_end(h, n);
n += get_entry(h, n)->next_offset;
assert(h->info.hook_entry[NF_IP6_POST_ROUTING] == n);
user_offset = h->info.hook_entry[NF_IP6_POST_ROUTING];
}
} else if (strcmp(h->info.name, "raw") == 0) {
assert(h->info.valid_hooks
== (1 << NF_IP6_PRE_ROUTING
| 1 << NF_IP6_LOCAL_OUT));
/* Hooks should be first three */
assert(h->info.hook_entry[NF_IP6_PRE_ROUTING] == 0);
n = get_chain_end(h, n);
n += get_entry(h, n)->next_offset;
assert(h->info.hook_entry[NF_IP6_LOCAL_OUT] == n);
user_offset = h->info.hook_entry[NF_IP6_LOCAL_OUT];
} else {
fprintf(stderr, "Unknown table `%s'\n", h->info.name);
abort();
}
/* User chain == end of last builtin + policy entry */
user_offset = get_chain_end(h, user_offset);
user_offset += get_entry(h, user_offset)->next_offset;
/* Overflows should be end of entry chains, and unconditional
policy nodes. */
for (i = 0; i < NUMHOOKS; i++) {
STRUCT_ENTRY *e;
STRUCT_STANDARD_TARGET *t;
if (!(h->info.valid_hooks & (1 << i)))
continue;
assert(h->info.underflow[i]
== get_chain_end(h, h->info.hook_entry[i]));
e = get_entry(h, get_chain_end(h, h->info.hook_entry[i]));
assert(unconditional(&e->ipv6));
assert(e->target_offset == sizeof(*e));
t = (STRUCT_STANDARD_TARGET *)GET_TARGET(e);
printf("target_size=%u, align=%u\n",
t->target.u.target_size, ALIGN(sizeof(*t)));
assert(t->target.u.target_size == ALIGN(sizeof(*t)));
assert(e->next_offset == sizeof(*e) + ALIGN(sizeof(*t)));
assert(strcmp(t->target.u.user.name, STANDARD_TARGET)==0);
assert(t->verdict == -NF_DROP-1 || t->verdict == -NF_ACCEPT-1);
/* Hooks and underflows must be valid entries */
iptcb_entry2index(h, get_entry(h, h->info.hook_entry[i]));
iptcb_entry2index(h, get_entry(h, h->info.underflow[i]));
}
assert(h->info.size
>= h->info.num_entries * (sizeof(STRUCT_ENTRY)
+sizeof(STRUCT_STANDARD_TARGET)));
assert(h->entries.size
>= (h->new_number
* (sizeof(STRUCT_ENTRY)
+ sizeof(STRUCT_STANDARD_TARGET))));
assert(strcmp(h->info.name, h->entries.name) == 0);
i = 0; n = 0;
was_return = 0;
#if 0
/* Check all the entries. */
ENTRY_ITERATE(h->entries.entrytable, h->entries.size,
check_entry, &i, &n, user_offset, &was_return, h);
assert(i == h->new_number);
assert(n == h->entries.size);
/* Final entry must be error node */
assert(strcmp(GET_TARGET(index2entry(h, h->new_number-1))
->u.user.name,
ERROR_TARGET) == 0);
#endif
}
#endif /*IPTC_DEBUG*/