/* Library which manipulates firewall rules. Version $Revision: 6665 $ */
/* 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).
* (C) 2000-2004 by the Netfilter Core Team <coreteam@netfilter.org>
*
* 2003-Jun-20: Harald Welte <laforge@netfilter.org>:
* - Reimplementation of chain cache to use offsets instead of entries
* 2003-Jun-23: Harald Welte <laforge@netfilter.org>:
* - performance optimization, sponsored by Astaro AG (http://www.astaro.com/)
* don't rebuild the chain cache after every operation, instead fix it
* up after a ruleset change.
* 2004-Aug-18: Harald Welte <laforge@netfilter.org>:
* - futher performance work: total reimplementation of libiptc.
* - libiptc now has a real internal (linked-list) represntation of the
* ruleset and a parser/compiler from/to this internal representation
* - again sponsored by Astaro AG (http://www.astaro.com/)
*/
#include <sys/types.h>
#include <sys/socket.h>
#include "linux_list.h"
//#define IPTC_DEBUG2 1
#ifdef IPTC_DEBUG2
#include <fcntl.h>
#define DEBUGP(x, args...) fprintf(stderr, "%s: " x, __FUNCTION__, ## args)
#define DEBUGP_C(x, args...) fprintf(stderr, x, ## args)
#else
#define DEBUGP(x, args...)
#define DEBUGP_C(x, args...)
#endif
#ifndef IPT_LIB_DIR
#define IPT_LIB_DIR "/usr/local/lib/iptables"
#endif
static int sockfd = -1;
static int sockfd_use = 0;
static void *iptc_fn = NULL;
static const char *hooknames[]
= { [HOOK_PRE_ROUTING] "PREROUTING",
[HOOK_LOCAL_IN] "INPUT",
[HOOK_FORWARD] "FORWARD",
[HOOK_LOCAL_OUT] "OUTPUT",
[HOOK_POST_ROUTING] "POSTROUTING",
#ifdef HOOK_DROPPING
[HOOK_DROPPING] "DROPPING"
#endif
};
/* Convenience structures */
struct ipt_error_target
{
STRUCT_ENTRY_TARGET t;
char error[TABLE_MAXNAMELEN];
};
struct chain_head;
struct rule_head;
struct counter_map
{
enum {
COUNTER_MAP_NOMAP,
COUNTER_MAP_NORMAL_MAP,
COUNTER_MAP_ZEROED,
COUNTER_MAP_SET
} maptype;
unsigned int mappos;
};
enum iptcc_rule_type {
IPTCC_R_STANDARD, /* standard target (ACCEPT, ...) */
IPTCC_R_MODULE, /* extension module (SNAT, ...) */
IPTCC_R_FALLTHROUGH, /* fallthrough rule */
IPTCC_R_JUMP, /* jump to other chain */
};
struct rule_head
{
struct list_head list;
struct chain_head *chain;
struct counter_map counter_map;
unsigned int index; /* index (needed for counter_map) */
unsigned int offset; /* offset in rule blob */
enum iptcc_rule_type type;
struct chain_head *jump; /* jump target, if IPTCC_R_JUMP */
unsigned int size; /* size of entry data */
STRUCT_ENTRY entry[0];
};
struct chain_head
{
struct list_head list;
char name[TABLE_MAXNAMELEN];
unsigned int hooknum; /* hook number+1 if builtin */
unsigned int references; /* how many jumps reference us */
int verdict; /* verdict if builtin */
STRUCT_COUNTERS counters; /* per-chain counters */
struct counter_map counter_map;
unsigned int num_rules; /* number of rules in list */
struct list_head rules; /* list of rules */
unsigned int index; /* index (needed for jump resolval) */
unsigned int head_offset; /* offset in rule blob */
unsigned int foot_index; /* index (needed for counter_map) */
unsigned int foot_offset; /* offset in rule blob */
};
STRUCT_TC_HANDLE
{
int changed; /* Have changes been made? */
struct list_head chains;
struct chain_head *chain_iterator_cur;
struct rule_head *rule_iterator_cur;
STRUCT_GETINFO info;
STRUCT_GET_ENTRIES *entries;
};
/* allocate a new chain head for the cache */
static struct chain_head *iptcc_alloc_chain_head(const char *name, int hooknum)
{
struct chain_head *c = malloc(sizeof(*c));
if (!c)
return NULL;
memset(c, 0, sizeof(*c));
strncpy(c->name, name, TABLE_MAXNAMELEN);
c->hooknum = hooknum;
INIT_LIST_HEAD(&c->rules);
return c;
}
/* allocate and initialize a new rule for the cache */
static struct rule_head *iptcc_alloc_rule(struct chain_head *c, unsigned int size)
{
struct rule_head *r = malloc(sizeof(*r)+size);
if (!r)
return NULL;
memset(r, 0, sizeof(*r));
r->chain = c;
r->size = size;
return r;
}
/* notify us that the ruleset has been modified by the user */
static void
set_changed(TC_HANDLE_T h)
{
h->changed = 1;
}
#ifdef IPTC_DEBUG
static void do_check(TC_HANDLE_T h, unsigned int line);
#define CHECK(h) do { if (!getenv("IPTC_NO_CHECK")) do_check((h), __LINE__); } while(0)
#else
#define CHECK(h)
#endif
/**********************************************************************
* iptc blob utility functions (iptcb_*)
**********************************************************************/
static inline int
iptcb_get_number(const STRUCT_ENTRY *i,
const STRUCT_ENTRY *seek,
unsigned int *pos)
{
if (i == seek)
return 1;
(*pos)++;
return 0;
}
static inline int
iptcb_get_entry_n(STRUCT_ENTRY *i,
unsigned int number,
unsigned int *pos,
STRUCT_ENTRY **pe)
{
if (*pos == number) {
*pe = i;
return 1;
}
(*pos)++;
return 0;
}
static inline STRUCT_ENTRY *
iptcb_get_entry(TC_HANDLE_T h, unsigned int offset)
{
return (STRUCT_ENTRY *)((char *)h->entries->entrytable + offset);
}
static unsigned int
iptcb_entry2index(const TC_HANDLE_T h, const STRUCT_ENTRY *seek)
{
unsigned int pos = 0;
if (ENTRY_ITERATE(h->entries->entrytable, h->entries->size,
iptcb_get_number, seek, &pos) == 0) {
fprintf(stderr, "ERROR: offset %u not an entry!\n",
(unsigned int)((char *)seek - (char *)h->entries->entrytable));
abort();
}
return pos;
}
static inline STRUCT_ENTRY *
iptcb_offset2entry(TC_HANDLE_T h, unsigned int offset)
{
return (STRUCT_ENTRY *) ((void *)h->entries->entrytable+offset);
}
static inline unsigned long
iptcb_entry2offset(const TC_HANDLE_T h, const STRUCT_ENTRY *e)
{
return (void *)e - (void *)h->entries->entrytable;
}
static inline unsigned int
iptcb_offset2index(const TC_HANDLE_T h, unsigned int offset)
{
return iptcb_entry2index(h, iptcb_offset2entry(h, offset));
}
/* Returns 0 if not hook entry, else hooknumber + 1 */
static inline unsigned int
iptcb_ent_is_hook_entry(STRUCT_ENTRY *e, TC_HANDLE_T h)
{
unsigned int i;
for (i = 0; i < NUMHOOKS; i++) {
if ((h->info.valid_hooks & (1 << i))
&& iptcb_get_entry(h, h->info.hook_entry[i]) == e)
return i+1;
}
return 0;
}
/**********************************************************************
* iptc cache utility functions (iptcc_*)
**********************************************************************/
/* Is the given chain builtin (1) or user-defined (0) */
static unsigned int iptcc_is_builtin(struct chain_head *c)
{
return (c->hooknum ? 1 : 0);
}
/* Get a specific rule within a chain */
static struct rule_head *iptcc_get_rule_num(struct chain_head *c,
unsigned int rulenum)
{
struct rule_head *r;
unsigned int num = 0;
list_for_each_entry(r, &c->rules, list) {
num++;
if (num == rulenum)
return r;
}
return NULL;
}
/* Get a specific rule within a chain backwards */
static struct rule_head *iptcc_get_rule_num_reverse(struct chain_head *c,
unsigned int rulenum)
{
struct rule_head *r;
unsigned int num = 0;
list_for_each_entry_reverse(r, &c->rules, list) {
num++;
if (num == rulenum)
return r;
}
return NULL;
}
/* Returns chain head if found, otherwise NULL. */
static struct chain_head *
iptcc_find_chain_by_offset(TC_HANDLE_T handle, unsigned int offset)
{
struct list_head *pos;
if (list_empty(&handle->chains))
return NULL;
list_for_each(pos, &handle->chains) {
struct chain_head *c = list_entry(pos, struct chain_head, list);
if (offset >= c->head_offset && offset <= c->foot_offset)
return c;
}
return NULL;
}
/* Returns chain head if found, otherwise NULL. */
static struct chain_head *
iptcc_find_label(const char *name, TC_HANDLE_T handle)
{
struct list_head *pos;
if (list_empty(&handle->chains))
return NULL;
list_for_each(pos, &handle->chains) {
struct chain_head *c = list_entry(pos, struct chain_head, list);
if (!strcmp(c->name, name))
return c;
}
return NULL;
}
/* called when rule is to be removed from cache */
static void iptcc_delete_rule(struct rule_head *r)
{
DEBUGP("deleting rule %p (offset %u)\n", r, r->offset);
/* clean up reference count of called chain */
if (r->type == IPTCC_R_JUMP
&& r->jump)
r->jump->references--;
list_del(&r->list);
free(r);
}
/**********************************************************************
* RULESET PARSER (blob -> cache)
**********************************************************************/
/* Delete policy rule of previous chain, since cache doesn't contain
* chain policy rules.
* WARNING: This function has ugly design and relies on a lot of context, only
* to be called from specific places within the parser */
static int __iptcc_p_del_policy(TC_HANDLE_T h, unsigned int num)
{
if (h->chain_iterator_cur) {
/* policy rule is last rule */
struct rule_head *pr = (struct rule_head *)
h->chain_iterator_cur->rules.prev;
/* save verdict */
h->chain_iterator_cur->verdict =
*(int *)GET_TARGET(pr->entry)->data;
/* save counter and counter_map information */
h->chain_iterator_cur->counter_map.maptype =
COUNTER_MAP_NORMAL_MAP;
h->chain_iterator_cur->counter_map.mappos = num-1;
memcpy(&h->chain_iterator_cur->counters, &pr->entry->counters,
sizeof(h->chain_iterator_cur->counters));
/* foot_offset points to verdict rule */
h->chain_iterator_cur->foot_index = num;
h->chain_iterator_cur->foot_offset = pr->offset;
/* delete rule from cache */
iptcc_delete_rule(pr);
h->chain_iterator_cur->num_rules--;
return 1;
}
return 0;
}
/* alphabetically insert a chain into the list */
static inline void iptc_insert_chain(TC_HANDLE_T h, struct chain_head *c)
{
struct chain_head *tmp;
/* sort only user defined chains */
if (!c->hooknum) {
list_for_each_entry(tmp, &h->chains, list) {
if (!tmp->hooknum && strcmp(c->name, tmp->name) <= 0) {
list_add(&c->list, tmp->list.prev);
return;
}
}
}
/* survived till end of list: add at tail */
list_add_tail(&c->list, &h->chains);
}
/* Another ugly helper function split out of cache_add_entry to make it less
* spaghetti code */
static void __iptcc_p_add_chain(TC_HANDLE_T h, struct chain_head *c,
unsigned int offset, unsigned int *num)
{
__iptcc_p_del_policy(h, *num);
c->head_offset = offset;
c->index = *num;
iptc_insert_chain(h, c);
h->chain_iterator_cur = c;
}
/* main parser function: add an entry from the blob to the cache */
static int cache_add_entry(STRUCT_ENTRY *e,
TC_HANDLE_T h,
STRUCT_ENTRY **prev,
unsigned int *num)
{
unsigned int builtin;
unsigned int offset = (char *)e - (char *)h->entries->entrytable;
DEBUGP("entering...");
/* Last entry ("policy rule"). End it.*/
if (iptcb_entry2offset(h,e) + e->next_offset == h->entries->size) {
/* This is the ERROR node at the end of the chain */
DEBUGP_C("%u:%u: end of table:\n", *num, offset);
__iptcc_p_del_policy(h, *num);
h->chain_iterator_cur = NULL;
goto out_inc;
}
/* We know this is the start of a new chain if it's an ERROR
* target, or a hook entry point */
if (strcmp(GET_TARGET(e)->u.user.name, ERROR_TARGET) == 0) {
struct chain_head *c =
iptcc_alloc_chain_head((const char *)GET_TARGET(e)->data, 0);
DEBUGP_C("%u:%u:new userdefined chain %s: %p\n", *num, offset,
(char *)c->name, c);
if (!c) {
errno = -ENOMEM;
return -1;
}
__iptcc_p_add_chain(h, c, offset, num);
} else if ((builtin = iptcb_ent_is_hook_entry(e, h)) != 0) {
struct chain_head *c =
iptcc_alloc_chain_head((char *)hooknames[builtin-1],
builtin);
DEBUGP_C("%u:%u new builtin chain: %p (rules=%p)\n",
*num, offset, c, &c->rules);
if (!c) {
errno = -ENOMEM;
return -1;
}
c->hooknum = builtin;
__iptcc_p_add_chain(h, c, offset, num);
/* FIXME: this is ugly. */
goto new_rule;
} else {
/* has to be normal rule */
struct rule_head *r;
new_rule:
if (!(r = iptcc_alloc_rule(h->chain_iterator_cur,
e->next_offset))) {
errno = ENOMEM;
return -1;
}
DEBUGP_C("%u:%u normal rule: %p: ", *num, offset, r);
r->index = *num;
r->offset = offset;
memcpy(r->entry, e, e->next_offset);
r->counter_map.maptype = COUNTER_MAP_NORMAL_MAP;
r->counter_map.mappos = r->index;
/* handling of jumps, etc. */
if (!strcmp(GET_TARGET(e)->u.user.name, STANDARD_TARGET)) {
STRUCT_STANDARD_TARGET *t;
t = (STRUCT_STANDARD_TARGET *)GET_TARGET(e);
if (t->target.u.target_size
!= ALIGN(sizeof(STRUCT_STANDARD_TARGET))) {
errno = EINVAL;
return -1;
}
if (t->verdict < 0) {
DEBUGP_C("standard, verdict=%d\n", t->verdict);
r->type = IPTCC_R_STANDARD;
} else if (t->verdict == r->offset+e->next_offset) {
DEBUGP_C("fallthrough\n");
r->type = IPTCC_R_FALLTHROUGH;
} else {
DEBUGP_C("jump, target=%u\n", t->verdict);
r->type = IPTCC_R_JUMP;
/* Jump target fixup has to be deferred
* until second pass, since we migh not
* yet have parsed the target */
}
} else {
DEBUGP_C("module, target=%s\n", GET_TARGET(e)->u.user.name);
r->type = IPTCC_R_MODULE;
}
list_add_tail(&r->list, &h->chain_iterator_cur->rules);
h->chain_iterator_cur->num_rules++;
}
out_inc:
(*num)++;
return 0;
}
/* parse an iptables blob into it's pieces */
static int parse_table(TC_HANDLE_T h)
{
STRUCT_ENTRY *prev;
unsigned int num = 0;
struct chain_head *c;
/* First pass: over ruleset blob */
ENTRY_ITERATE(h->entries->entrytable, h->entries->size,
cache_add_entry, h, &prev, &num);
/* Second pass: fixup parsed data from first pass */
list_for_each_entry(c, &h->chains, list) {
struct rule_head *r;
list_for_each_entry(r, &c->rules, list) {
struct chain_head *c;
STRUCT_STANDARD_TARGET *t;
if (r->type != IPTCC_R_JUMP)
continue;
t = (STRUCT_STANDARD_TARGET *)GET_TARGET(r->entry);
c = iptcc_find_chain_by_offset(h, t->verdict);
if (!c)
return -1;
r->jump = c;
c->references++;
}
}
/* FIXME: sort chains */
return 1;
}
/**********************************************************************
* RULESET COMPILATION (cache -> blob)
**********************************************************************/
/* Convenience structures */
struct iptcb_chain_start{
STRUCT_ENTRY e;
struct ipt_error_target name;
};
#define IPTCB_CHAIN_START_SIZE (sizeof(STRUCT_ENTRY) + \
ALIGN(sizeof(struct ipt_error_target)))
struct iptcb_chain_foot {
STRUCT_ENTRY e;
STRUCT_STANDARD_TARGET target;
};
#define IPTCB_CHAIN_FOOT_SIZE (sizeof(STRUCT_ENTRY) + \
ALIGN(sizeof(STRUCT_STANDARD_TARGET)))
struct iptcb_chain_error {
STRUCT_ENTRY entry;
struct ipt_error_target target;
};
#define IPTCB_CHAIN_ERROR_SIZE (sizeof(STRUCT_ENTRY) + \
ALIGN(sizeof(struct ipt_error_target)))
/* compile rule from cache into blob */
static inline int iptcc_compile_rule (TC_HANDLE_T h, STRUCT_REPLACE *repl, struct rule_head *r)
{
/* handle jumps */
if (r->type == IPTCC_R_JUMP) {
STRUCT_STANDARD_TARGET *t;
t = (STRUCT_STANDARD_TARGET *)GET_TARGET(r->entry);
/* memset for memcmp convenience on delete/replace */
memset(t->target.u.user.name, 0, FUNCTION_MAXNAMELEN);
strcpy(t->target.u.user.name, STANDARD_TARGET);
/* Jumps can only happen to builtin chains, so we
* can safely assume that they always have a header */
t->verdict = r->jump->head_offset + IPTCB_CHAIN_START_SIZE;
} else if (r->type == IPTCC_R_FALLTHROUGH) {
STRUCT_STANDARD_TARGET *t;
t = (STRUCT_STANDARD_TARGET *)GET_TARGET(r->entry);
t->verdict = r->offset + r->size;
}
/* copy entry from cache to blob */
memcpy((char *)repl->entries+r->offset, r->entry, r->size);
return 1;
}
/* compile chain from cache into blob */
static int iptcc_compile_chain(TC_HANDLE_T h, STRUCT_REPLACE *repl, struct chain_head *c)
{
int ret;
struct rule_head *r;
struct iptcb_chain_start *head;
struct iptcb_chain_foot *foot;
/* only user-defined chains have heaer */
if (!iptcc_is_builtin(c)) {
/* put chain header in place */
head = (void *)repl->entries + c->head_offset;
head->e.target_offset = sizeof(STRUCT_ENTRY);
head->e.next_offset = IPTCB_CHAIN_START_SIZE;
strcpy(head->name.t.u.user.name, ERROR_TARGET);
head->name.t.u.target_size =
ALIGN(sizeof(struct ipt_error_target));
strcpy(head->name.error, c->name);
} else {
repl->hook_entry[c->hooknum-1] = c->head_offset;
repl->underflow[c->hooknum-1] = c->foot_offset;
}
/* iterate over rules */
list_for_each_entry(r, &c->rules, list) {
ret = iptcc_compile_rule(h, repl, r);
if (ret < 0)
return ret;
}
/* put chain footer in place */
foot = (void *)repl->entries + c->foot_offset;
foot->e.target_offset = sizeof(STRUCT_ENTRY);
foot->e.next_offset = IPTCB_CHAIN_FOOT_SIZE;
strcpy(foot->target.target.u.user.name, STANDARD_TARGET);
foot->target.target.u.target_size =
ALIGN(sizeof(STRUCT_STANDARD_TARGET));
/* builtin targets have verdict, others return */
if (iptcc_is_builtin(c))
foot->target.verdict = c->verdict;
else
foot->target.verdict = RETURN;
/* set policy-counters */
memcpy(&foot->e.counters, &c->counters, sizeof(STRUCT_COUNTERS));
return 0;
}
/* calculate offset and number for every rule in the cache */
static int iptcc_compile_chain_offsets(TC_HANDLE_T h, struct chain_head *c,
unsigned int *offset, unsigned int *num)
{
struct rule_head *r;
c->head_offset = *offset;
DEBUGP("%s: chain_head %u, offset=%u\n", c->name, *num, *offset);
if (!iptcc_is_builtin(c)) {
/* Chain has header */
*offset += sizeof(STRUCT_ENTRY)
+ ALIGN(sizeof(struct ipt_error_target));
(*num)++;
}
list_for_each_entry(r, &c->rules, list) {
DEBUGP("rule %u, offset=%u, index=%u\n", *num, *offset, *num);
r->offset = *offset;
r->index = *num;
*offset += r->size;
(*num)++;
}
DEBUGP("%s; chain_foot %u, offset=%u, index=%u\n", c->name, *num,
*offset, *num);
c->foot_offset = *offset;
c->foot_index = *num;
*offset += sizeof(STRUCT_ENTRY)
+ ALIGN(sizeof(STRUCT_STANDARD_TARGET));
(*num)++;
return 1;
}
/* put the pieces back together again */
static int iptcc_compile_table_prep(TC_HANDLE_T h, unsigned int *size)
{
struct chain_head *c;
unsigned int offset = 0, num = 0;
int ret = 0;
/* First pass: calculate offset for every rule */
list_for_each_entry(c, &h->chains, list) {
ret = iptcc_compile_chain_offsets(h, c, &offset, &num);
if (ret < 0)
return ret;
}
/* Append one error rule at end of chain */
num++;
offset += sizeof(STRUCT_ENTRY)
+ ALIGN(sizeof(struct ipt_error_target));
/* ruleset size is now in offset */
*size = offset;
return num;
}
static int iptcc_compile_table(TC_HANDLE_T h, STRUCT_REPLACE *repl)
{
struct chain_head *c;
struct iptcb_chain_error *error;
/* Second pass: copy from cache to offsets, fill in jumps */
list_for_each_entry(c, &h->chains, list) {
int ret = iptcc_compile_chain(h, repl, c);
if (ret < 0)
return ret;
}
/* Append error rule at end of chain */
error = (void *)repl->entries + repl->size - IPTCB_CHAIN_ERROR_SIZE;
error->entry.target_offset = sizeof(STRUCT_ENTRY);
error->entry.next_offset = IPTCB_CHAIN_ERROR_SIZE;
error->target.t.u.user.target_size =
ALIGN(sizeof(struct ipt_error_target));
strcpy((char *)&error->target.t.u.user.name, ERROR_TARGET);
strcpy((char *)&error->target.error, "ERROR");
return 1;
}
/**********************************************************************
* EXTERNAL API (operates on cache only)
**********************************************************************/
/* Allocate handle of given size */
static TC_HANDLE_T
alloc_handle(const char *tablename, unsigned int size, unsigned int num_rules)
{
size_t len;
TC_HANDLE_T h;
len = sizeof(STRUCT_TC_HANDLE) + size;
h = malloc(sizeof(STRUCT_TC_HANDLE));
if (!h) {
errno = ENOMEM;
return NULL;
}
memset(h, 0, sizeof(*h));
INIT_LIST_HEAD(&h->chains);
strcpy(h->info.name, tablename);
h->entries = malloc(sizeof(STRUCT_GET_ENTRIES) + size);
if (!h->entries)
goto out_free_handle;
strcpy(h->entries->name, tablename);
h->entries->size = size;
return h;
out_free_handle:
free(h);
return NULL;
}
TC_HANDLE_T
TC_INIT(const char *tablename)
{
TC_HANDLE_T h;
STRUCT_GETINFO info;
unsigned int tmp;
socklen_t s;
iptc_fn = TC_INIT;
if (strlen(tablename) >= TABLE_MAXNAMELEN) {
errno = EINVAL;
return NULL;
}
if (sockfd_use == 0) {
sockfd = socket(TC_AF, SOCK_RAW, IPPROTO_RAW);
if (sockfd < 0)
return NULL;
}
sockfd_use++;
s = sizeof(info);
strcpy(info.name, tablename);
if (getsockopt(sockfd, TC_IPPROTO, SO_GET_INFO, &info, &s) < 0) {
if (--sockfd_use == 0) {
close(sockfd);
sockfd = -1;
}
return NULL;
}
DEBUGP("valid_hooks=0x%08x, num_entries=%u, size=%u\n",
info.valid_hooks, info.num_entries, info.size);
if ((h = alloc_handle(info.name, info.size, info.num_entries))
== NULL) {
if (--sockfd_use == 0) {
close(sockfd);
sockfd = -1;
}
return NULL;
}
/* Initialize current state */
h->info = info;
h->entries->size = h->info.size;
tmp = sizeof(STRUCT_GET_ENTRIES) + h->info.size;
if (getsockopt(sockfd, TC_IPPROTO, SO_GET_ENTRIES, h->entries,
&tmp) < 0)
goto error;
#ifdef IPTC_DEBUG2
{
int fd = open("/tmp/libiptc-so_get_entries.blob",
O_CREAT|O_WRONLY);
if (fd >= 0) {
write(fd, h->entries, tmp);
close(fd);
}
}
#endif
if (parse_table(h) < 0)
goto error;
CHECK(h);
return h;
error:
if (--sockfd_use == 0) {
close(sockfd);
sockfd = -1;
}
TC_FREE(&h);
return NULL;
}
void
TC_FREE(TC_HANDLE_T *h)
{
struct chain_head *c, *tmp;
iptc_fn = TC_FREE;
if (--sockfd_use == 0) {
close(sockfd);
sockfd = -1;
}
list_for_each_entry_safe(c, tmp, &(*h)->chains, list) {
struct rule_head *r, *rtmp;
list_for_each_entry_safe(r, rtmp, &c->rules, list) {
free(r);
}
free(c);
}
free((*h)->entries);
free(*h);
*h = NULL;
}
static inline int
print_match(const STRUCT_ENTRY_MATCH *m)
{
printf("Match name: `%s'\n", m->u.user.name);
return 0;
}
static int dump_entry(STRUCT_ENTRY *e, const TC_HANDLE_T handle);
void
TC_DUMP_ENTRIES(const TC_HANDLE_T handle)
{
iptc_fn = TC_DUMP_ENTRIES;
CHECK(handle);
#if 0
printf("libiptc v%s. %u bytes.\n",
IPTABLES_VERSION, handle->entries->size);
printf("Table `%s'\n", handle->info.name);
printf("Hooks: pre/in/fwd/out/post = %u/%u/%u/%u/%u\n",
handle->info.hook_entry[HOOK_PRE_ROUTING],
handle->info.hook_entry[HOOK_LOCAL_IN],
handle->info.hook_entry[HOOK_FORWARD],
handle->info.hook_entry[HOOK_LOCAL_OUT],
handle->info.hook_entry[HOOK_POST_ROUTING]);
printf("Underflows: pre/in/fwd/out/post = %u/%u/%u/%u/%u\n",
handle->info.underflow[HOOK_PRE_ROUTING],
handle->info.underflow[HOOK_LOCAL_IN],
handle->info.underflow[HOOK_FORWARD],
handle->info.underflow[HOOK_LOCAL_OUT],
handle->info.underflow[HOOK_POST_ROUTING]);
ENTRY_ITERATE(handle->entries->entrytable, handle->entries->size,
dump_entry, handle);
#endif
}
/* Does this chain exist? */
int TC_IS_CHAIN(const char *chain, const TC_HANDLE_T handle)
{
iptc_fn = TC_IS_CHAIN;
return iptcc_find_label(chain, handle) != NULL;
}
static void iptcc_chain_iterator_advance(TC_HANDLE_T handle)
{
struct chain_head *c = handle->chain_iterator_cur;
if (c->list.next == &handle->chains)
handle->chain_iterator_cur = NULL;
else
handle->chain_iterator_cur =
list_entry(c->list.next, struct chain_head, list);
}
/* Iterator functions to run through the chains. */
const char *
TC_FIRST_CHAIN(TC_HANDLE_T *handle)
{
struct chain_head *c = list_entry((*handle)->chains.next,
struct chain_head, list);
iptc_fn = TC_FIRST_CHAIN;
if (list_empty(&(*handle)->chains)) {
DEBUGP(": no chains\n");
return NULL;
}
(*handle)->chain_iterator_cur = c;
iptcc_chain_iterator_advance(*handle);
DEBUGP(": returning `%s'\n", c->name);
return c->name;
}
/* Iterator functions to run through the chains. Returns NULL at end. */
const char *
TC_NEXT_CHAIN(TC_HANDLE_T *handle)
{
struct chain_head *c = (*handle)->chain_iterator_cur;
iptc_fn = TC_NEXT_CHAIN;
if (!c) {
DEBUGP(": no more chains\n");
return NULL;
}
iptcc_chain_iterator_advance(*handle);
DEBUGP(": returning `%s'\n", c->name);
return c->name;
}
/* Get first rule in the given chain: NULL for empty chain. */
const STRUCT_ENTRY *
TC_FIRST_RULE(const char *chain, TC_HANDLE_T *handle)
{
struct chain_head *c;
struct rule_head *r;
iptc_fn = TC_FIRST_RULE;
DEBUGP("first rule(%s): ", chain);
c = iptcc_find_label(chain, *handle);
if (!c) {
errno = ENOENT;
return NULL;
}
/* Empty chain: single return/policy rule */
if (list_empty(&c->rules)) {
DEBUGP_C("no rules, returning NULL\n");
return NULL;
}
r = list_entry(c->rules.next, struct rule_head, list);
(*handle)->rule_iterator_cur = r;
DEBUGP_C("%p\n", r);
return r->entry;
}
/* Returns NULL when rules run out. */
const STRUCT_ENTRY *
TC_NEXT_RULE(const STRUCT_ENTRY *prev, TC_HANDLE_T *handle)
{
struct rule_head *r;
iptc_fn = TC_NEXT_RULE;
DEBUGP("rule_iterator_cur=%p...", (*handle)->rule_iterator_cur);
if (!(*handle)->rule_iterator_cur) {
DEBUGP_C("returning NULL\n");
return NULL;
}
r = list_entry((*handle)->rule_iterator_cur->list.next,
struct rule_head, list);
iptc_fn = TC_NEXT_RULE;
DEBUGP_C("next=%p, head=%p...", &r->list,
&(*handle)->rule_iterator_cur->chain->rules);
if (&r->list == &(*handle)->rule_iterator_cur->chain->rules) {
(*handle)->rule_iterator_cur = NULL;
DEBUGP_C("finished, returning NULL\n");
return NULL;
}
(*handle)->rule_iterator_cur = r;
/* NOTE: prev is without any influence ! */
DEBUGP_C("returning rule %p\n", r);
return r->entry;
}
/* How many rules in this chain? */
unsigned int
TC_NUM_RULES(const char *chain, TC_HANDLE_T *handle)
{
struct chain_head *c;
iptc_fn = TC_NUM_RULES;
CHECK(*handle);
c = iptcc_find_label(chain, *handle);
if (!c) {
errno = ENOENT;
return (unsigned int)-1;
}
return c->num_rules;
}
const STRUCT_ENTRY *TC_GET_RULE(const char *chain,
unsigned int n,
TC_HANDLE_T *handle)
{
struct chain_head *c;
struct rule_head *r;
iptc_fn = TC_GET_RULE;
CHECK(*handle);
c = iptcc_find_label(chain, *handle);
if (!c) {
errno = ENOENT;
return NULL;
}
r = iptcc_get_rule_num(c, n);
if (!r)
return NULL;
return r->entry;
}
/* Returns a pointer to the target name of this position. */
const char *standard_target_map(int verdict)
{
switch (verdict) {
case RETURN:
return LABEL_RETURN;
break;
case -NF_ACCEPT-1:
return LABEL_ACCEPT;
break;
case -NF_DROP-1:
return LABEL_DROP;
break;
case -NF_QUEUE-1:
return LABEL_QUEUE;
break;
default:
fprintf(stderr, "ERROR: %d not a valid target)\n",
verdict);
abort();
break;
}
/* not reached */
return NULL;
}
/* Returns a pointer to the target name of this position. */
const char *TC_GET_TARGET(const STRUCT_ENTRY *ce,
TC_HANDLE_T *handle)
{
STRUCT_ENTRY *e = (STRUCT_ENTRY *)ce;
struct rule_head *r = container_of(e, struct rule_head, entry[0]);
iptc_fn = TC_GET_TARGET;
switch(r->type) {
int spos;
case IPTCC_R_FALLTHROUGH:
return "";
break;
case IPTCC_R_JUMP:
DEBUGP("r=%p, jump=%p, name=`%s'\n", r, r->jump, r->jump->name);
return r->jump->name;
break;
case IPTCC_R_STANDARD:
spos = *(int *)GET_TARGET(e)->data;
DEBUGP("r=%p, spos=%d'\n", r, spos);
return standard_target_map(spos);
break;
case IPTCC_R_MODULE:
return GET_TARGET(e)->u.user.name;
break;
}
return NULL;
}
/* Is this a built-in chain? Actually returns hook + 1. */
int
TC_BUILTIN(const char *chain, const TC_HANDLE_T handle)
{
struct chain_head *c;
iptc_fn = TC_BUILTIN;
c = iptcc_find_label(chain, handle);
if (!c) {
errno = ENOENT;
return 0;
}
return iptcc_is_builtin(c);
}
/* Get the policy of a given built-in chain */
const char *
TC_GET_POLICY(const char *chain,
STRUCT_COUNTERS *counters,
TC_HANDLE_T *handle)
{
struct chain_head *c;
iptc_fn = TC_GET_POLICY;
DEBUGP("called for chain %s\n", chain);
c = iptcc_find_label(chain, *handle);
if (!c) {
errno = ENOENT;
return NULL;
}
if (!iptcc_is_builtin(c))
return NULL;
*counters = c->counters;
return standard_target_map(c->verdict);
}
static int
iptcc_standard_map(struct rule_head *r, int verdict)
{
STRUCT_ENTRY *e = r->entry;
STRUCT_STANDARD_TARGET *t;
t = (STRUCT_STANDARD_TARGET *)GET_TARGET(e);
if (t->target.u.target_size
!= ALIGN(sizeof(STRUCT_STANDARD_TARGET))) {
errno = EINVAL;
return 0;
}
/* memset for memcmp convenience on delete/replace */
memset(t->target.u.user.name, 0, FUNCTION_MAXNAMELEN);
strcpy(t->target.u.user.name, STANDARD_TARGET);
t->verdict = verdict;
r->type = IPTCC_R_STANDARD;
return 1;
}
static int
iptcc_map_target(const TC_HANDLE_T handle,
struct rule_head *r)
{
STRUCT_ENTRY *e = r->entry;
STRUCT_ENTRY_TARGET *t = GET_TARGET(e);
/* Maybe it's empty (=> fall through) */
if (strcmp(t->u.user.name, "") == 0) {
r->type = IPTCC_R_FALLTHROUGH;
return 1;
}
/* Maybe it's a standard target name... */
else if (strcmp(t->u.user.name, LABEL_ACCEPT) == 0)
return iptcc_standard_map(r, -NF_ACCEPT - 1);
else if (strcmp(t->u.user.name, LABEL_DROP) == 0)
return iptcc_standard_map(r, -NF_DROP - 1);
else if (strcmp(t->u.user.name, LABEL_QUEUE) == 0)
return iptcc_standard_map(r, -NF_QUEUE - 1);
else if (strcmp(t->u.user.name, LABEL_RETURN) == 0)
return iptcc_standard_map(r, RETURN);
else if (TC_BUILTIN(t->u.user.name, handle)) {
/* Can't jump to builtins. */
errno = EINVAL;
return 0;
} else {
/* Maybe it's an existing chain name. */
struct chain_head *c;
DEBUGP("trying to find chain `%s': ", t->u.user.name);
c = iptcc_find_label(t->u.user.name, handle);
if (c) {
DEBUGP_C("found!\n");
r->type = IPTCC_R_JUMP;
r->jump = c;
c->references++;
return 1;
}
DEBUGP_C("not found :(\n");
}
/* Must be a module? If not, kernel will reject... */
/* memset to all 0 for your memcmp convenience: don't clear version */
memset(t->u.user.name + strlen(t->u.user.name),
0,
FUNCTION_MAXNAMELEN - 1 - strlen(t->u.user.name));
r->type = IPTCC_R_MODULE;
set_changed(handle);
return 1;
}
/* Insert the entry `fw' in chain `chain' into position `rulenum'. */
int
TC_INSERT_ENTRY(const IPT_CHAINLABEL chain,
const STRUCT_ENTRY *e,
unsigned int rulenum,
TC_HANDLE_T *handle)
{
struct chain_head *c;
struct rule_head *r;
struct list_head *prev;
iptc_fn = TC_INSERT_ENTRY;
if (!(c = iptcc_find_label(chain, *handle))) {
errno = ENOENT;
return 0;
}
/* first rulenum index = 0
first c->num_rules index = 1 */
if (rulenum > c->num_rules) {
errno = E2BIG;
return 0;
}
/* If we are inserting at the end just take advantage of the
double linked list, insert will happen before the entry
prev points to. */
if (rulenum == c->num_rules) {
prev = &c->rules;
} else if (rulenum + 1 <= c->num_rules/2) {
r = iptcc_get_rule_num(c, rulenum + 1);
prev = &r->list;
} else {
r = iptcc_get_rule_num_reverse(c, c->num_rules - rulenum);
prev = &r->list;
}
if (!(r = iptcc_alloc_rule(c, e->next_offset))) {
errno = ENOMEM;
return 0;
}
memcpy(r->entry, e, e->next_offset);
r->counter_map.maptype = COUNTER_MAP_SET;
if (!iptcc_map_target(*handle, r)) {
free(r);
return 0;
}
list_add_tail(&r->list, prev);
c->num_rules++;
set_changed(*handle);
return 1;
}
/* Atomically replace rule `rulenum' in `chain' with `fw'. */
int
TC_REPLACE_ENTRY(const IPT_CHAINLABEL chain,
const STRUCT_ENTRY *e,
unsigned int rulenum,
TC_HANDLE_T *handle)
{
struct chain_head *c;
struct rule_head *r, *old;
iptc_fn = TC_REPLACE_ENTRY;
if (!(c = iptcc_find_label(chain, *handle))) {
errno = ENOENT;
return 0;
}
if (rulenum >= c->num_rules) {
errno = E2BIG;
return 0;
}
/* Take advantage of the double linked list if possible. */
if (rulenum + 1 <= c->num_rules/2) {
old = iptcc_get_rule_num(c, rulenum + 1);
} else {
old = iptcc_get_rule_num_reverse(c, c->num_rules - rulenum);
}
if (!(r = iptcc_alloc_rule(c, e->next_offset))) {
errno = ENOMEM;
return 0;
}
memcpy(r->entry, e, e->next_offset);
r->counter_map.maptype = COUNTER_MAP_SET;
if (!iptcc_map_target(*handle, r)) {
free(r);
return 0;
}
list_add(&r->list, &old->list);
iptcc_delete_rule(old);
set_changed(*handle);
return 1;
}
/* Append entry `fw' to chain `chain'. Equivalent to insert with
rulenum = length of chain. */
int
TC_APPEND_ENTRY(const IPT_CHAINLABEL chain,
const STRUCT_ENTRY *e,
TC_HANDLE_T *handle)
{
struct chain_head *c;
struct rule_head *r;
iptc_fn = TC_APPEND_ENTRY;
if (!(c = iptcc_find_label(chain, *handle))) {
DEBUGP("unable to find chain `%s'\n", chain);
errno = ENOENT;
return 0;
}
if (!(r = iptcc_alloc_rule(c, e->next_offset))) {
DEBUGP("unable to allocate rule for chain `%s'\n", chain);
errno = ENOMEM;
return 0;
}
memcpy(r->entry, e, e->next_offset);
r->counter_map.maptype = COUNTER_MAP_SET;
if (!iptcc_map_target(*handle, r)) {
DEBUGP("unable to map target of rule for chain `%s'\n", chain);
free(r);
return 0;
}
list_add_tail(&r->list, &c->rules);
c->num_rules++;
set_changed(*handle);
return 1;
}
static inline int
match_different(const STRUCT_ENTRY_MATCH *a,
const unsigned char *a_elems,
const unsigned char *b_elems,
unsigned char **maskptr)
{
const STRUCT_ENTRY_MATCH *b;
unsigned int i;
/* Offset of b is the same as a. */
b = (void *)b_elems + ((unsigned char *)a - a_elems);
if (a->u.match_size != b->u.match_size)
return 1;
if (strcmp(a->u.user.name, b->u.user.name) != 0)
return 1;
*maskptr += ALIGN(sizeof(*a));
for (i = 0; i < a->u.match_size - ALIGN(sizeof(*a)); i++)
if (((a->data[i] ^ b->data[i]) & (*maskptr)[i]) != 0)
return 1;
*maskptr += i;
return 0;
}
static inline int
target_same(struct rule_head *a, struct rule_head *b,const unsigned char *mask)
{
unsigned int i;
STRUCT_ENTRY_TARGET *ta, *tb;
if (a->type != b->type)
return 0;
ta = GET_TARGET(a->entry);
tb = GET_TARGET(b->entry);
switch (a->type) {
case IPTCC_R_FALLTHROUGH:
return 1;
case IPTCC_R_JUMP:
return a->jump == b->jump;
case IPTCC_R_STANDARD:
return ((STRUCT_STANDARD_TARGET *)ta)->verdict
== ((STRUCT_STANDARD_TARGET *)tb)->verdict;
case IPTCC_R_MODULE:
if (ta->u.target_size != tb->u.target_size)
return 0;
if (strcmp(ta->u.user.name, tb->u.user.name) != 0)
return 0;
for (i = 0; i < ta->u.target_size - sizeof(*ta); i++)
if (((ta->data[i] ^ tb->data[i]) & mask[i]) != 0)
return 0;
return 1;
default:
fprintf(stderr, "ERROR: bad type %i\n", a->type);
abort();
}
}
static unsigned char *
is_same(const STRUCT_ENTRY *a,
const STRUCT_ENTRY *b,
unsigned char *matchmask);
/* Delete the first rule in `chain' which matches `fw'. */
int
TC_DELETE_ENTRY(const IPT_CHAINLABEL chain,
const STRUCT_ENTRY *origfw,
unsigned char *matchmask,
TC_HANDLE_T *handle)
{
struct chain_head *c;
struct rule_head *r, *i;
iptc_fn = TC_DELETE_ENTRY;
if (!(c = iptcc_find_label(chain, *handle))) {
errno = ENOENT;
return 0;
}
/* Create a rule_head from origfw. */
r = iptcc_alloc_rule(c, origfw->next_offset);
if (!r) {
errno = ENOMEM;
return 0;
}
memcpy(r->entry, origfw, origfw->next_offset);
r->counter_map.maptype = COUNTER_MAP_NOMAP;
if (!iptcc_map_target(*handle, r)) {
DEBUGP("unable to map target of rule for chain `%s'\n", chain);
free(r);
return 0;
} else {
/* iptcc_map_target increment target chain references
* since this is a fake rule only used for matching
* the chain references count is decremented again.
*/
if (r->type == IPTCC_R_JUMP
&& r->jump)
r->jump->references--;
}
list_for_each_entry(i, &c->rules, list) {
unsigned char *mask;
mask = is_same(r->entry, i->entry, matchmask);
if (!mask)
continue;
if (!target_same(r, i, mask))
continue;
/* If we are about to delete the rule that is the
* current iterator, move rule iterator back. next
* pointer will then point to real next node */
if (i == (*handle)->rule_iterator_cur) {
(*handle)->rule_iterator_cur =
list_entry((*handle)->rule_iterator_cur->list.prev,
struct rule_head, list);
}
c->num_rules--;
iptcc_delete_rule(i);
set_changed(*handle);
free(r);
return 1;
}
free(r);
errno = ENOENT;
return 0;
}
/* Delete the rule in position `rulenum' in `chain'. */
int
TC_DELETE_NUM_ENTRY(const IPT_CHAINLABEL chain,
unsigned int rulenum,
TC_HANDLE_T *handle)
{
struct chain_head *c;
struct rule_head *r;
iptc_fn = TC_DELETE_NUM_ENTRY;
if (!(c = iptcc_find_label(chain, *handle))) {
errno = ENOENT;
return 0;
}
if (rulenum >= c->num_rules) {
errno = E2BIG;
return 0;
}
/* Take advantage of the double linked list if possible. */
if (rulenum + 1 <= c->num_rules/2) {
r = iptcc_get_rule_num(c, rulenum + 1);
} else {
r = iptcc_get_rule_num_reverse(c, c->num_rules - rulenum);
}
/* If we are about to delete the rule that is the current
* iterator, move rule iterator back. next pointer will then
* point to real next node */
if (r == (*handle)->rule_iterator_cur) {
(*handle)->rule_iterator_cur =
list_entry((*handle)->rule_iterator_cur->list.prev,
struct rule_head, list);
}
c->num_rules--;
iptcc_delete_rule(r);
set_changed(*handle);
return 1;
}
/* Check the packet `fw' on chain `chain'. Returns the verdict, or
NULL and sets errno. */
const char *
TC_CHECK_PACKET(const IPT_CHAINLABEL chain,
STRUCT_ENTRY *entry,
TC_HANDLE_T *handle)
{
iptc_fn = TC_CHECK_PACKET;
errno = ENOSYS;
return NULL;
}
/* Flushes the entries in the given chain (ie. empties chain). */
int
TC_FLUSH_ENTRIES(const IPT_CHAINLABEL chain, TC_HANDLE_T *handle)
{
struct chain_head *c;
struct rule_head *r, *tmp;
iptc_fn = TC_FLUSH_ENTRIES;
if (!(c = iptcc_find_label(chain, *handle))) {
errno = ENOENT;
return 0;
}
list_for_each_entry_safe(r, tmp, &c->rules, list) {
iptcc_delete_rule(r);
}
c->num_rules = 0;
set_changed(*handle);
return 1;
}
/* Zeroes the counters in a chain. */
int
TC_ZERO_ENTRIES(const IPT_CHAINLABEL chain, TC_HANDLE_T *handle)
{
struct chain_head *c;
struct rule_head *r;
iptc_fn = TC_ZERO_ENTRIES;
if (!(c = iptcc_find_label(chain, *handle))) {
errno = ENOENT;
return 0;
}
if (c->counter_map.maptype == COUNTER_MAP_NORMAL_MAP)
c->counter_map.maptype = COUNTER_MAP_ZEROED;
list_for_each_entry(r, &c->rules, list) {
if (r->counter_map.maptype == COUNTER_MAP_NORMAL_MAP)
r->counter_map.maptype = COUNTER_MAP_ZEROED;
}
set_changed(*handle);
return 1;
}
STRUCT_COUNTERS *
TC_READ_COUNTER(const IPT_CHAINLABEL chain,
unsigned int rulenum,
TC_HANDLE_T *handle)
{
struct chain_head *c;
struct rule_head *r;
iptc_fn = TC_READ_COUNTER;
CHECK(*handle);
if (!(c = iptcc_find_label(chain, *handle))) {
errno = ENOENT;
return NULL;
}
if (!(r = iptcc_get_rule_num(c, rulenum))) {
errno = E2BIG;
return NULL;
}
return &r->entry[0].counters;
}
int
TC_ZERO_COUNTER(const IPT_CHAINLABEL chain,
unsigned int rulenum,
TC_HANDLE_T *handle)
{
struct chain_head *c;
struct rule_head *r;
iptc_fn = TC_ZERO_COUNTER;
CHECK(*handle);
if (!(c = iptcc_find_label(chain, *handle))) {
errno = ENOENT;
return 0;
}
if (!(r = iptcc_get_rule_num(c, rulenum))) {
errno = E2BIG;
return 0;
}
if (r->counter_map.maptype == COUNTER_MAP_NORMAL_MAP)
r->counter_map.maptype = COUNTER_MAP_ZEROED;
set_changed(*handle);
return 1;
}
int
TC_SET_COUNTER(const IPT_CHAINLABEL chain,
unsigned int rulenum,
STRUCT_COUNTERS *counters,
TC_HANDLE_T *handle)
{
struct chain_head *c;
struct rule_head *r;
STRUCT_ENTRY *e;
iptc_fn = TC_SET_COUNTER;
CHECK(*handle);
if (!(c = iptcc_find_label(chain, *handle))) {
errno = ENOENT;
return 0;
}
if (!(r = iptcc_get_rule_num(c, rulenum))) {
errno = E2BIG;
return 0;
}
e = r->entry;
r->counter_map.maptype = COUNTER_MAP_SET;
memcpy(&e->counters, counters, sizeof(STRUCT_COUNTERS));
set_changed(*handle);
return 1;
}
/* Creates a new chain. */
/* To create a chain, create two rules: error node and unconditional
* return. */
int
TC_CREATE_CHAIN(const IPT_CHAINLABEL chain, TC_HANDLE_T *handle)
{
static struct chain_head *c;
iptc_fn = TC_CREATE_CHAIN;
/* find_label doesn't cover built-in targets: DROP, ACCEPT,
QUEUE, RETURN. */
if (iptcc_find_label(chain, *handle)
|| strcmp(chain, LABEL_DROP) == 0
|| strcmp(chain, LABEL_ACCEPT) == 0
|| strcmp(chain, LABEL_QUEUE) == 0
|| strcmp(chain, LABEL_RETURN) == 0) {
DEBUGP("Chain `%s' already exists\n", chain);
errno = EEXIST;
return 0;
}
if (strlen(chain)+1 > sizeof(IPT_CHAINLABEL)) {
DEBUGP("Chain name `%s' too long\n", chain);
errno = EINVAL;
return 0;
}
c = iptcc_alloc_chain_head(chain, 0);
if (!c) {
DEBUGP("Cannot allocate memory for chain `%s'\n", chain);
errno = ENOMEM;
return 0;
}
DEBUGP("Creating chain `%s'\n", chain);
list_add_tail(&c->list, &(*handle)->chains);
set_changed(*handle);
return 1;
}
/* Get the number of references to this chain. */
int
TC_GET_REFERENCES(unsigned int *ref, const IPT_CHAINLABEL chain,
TC_HANDLE_T *handle)
{
struct chain_head *c;
iptc_fn = TC_GET_REFERENCES;
if (!(c = iptcc_find_label(chain, *handle))) {
errno = ENOENT;
return 0;
}
*ref = c->references;
return 1;
}
/* Deletes a chain. */
int
TC_DELETE_CHAIN(const IPT_CHAINLABEL chain, TC_HANDLE_T *handle)
{
unsigned int references;
struct chain_head *c;
iptc_fn = TC_DELETE_CHAIN;
if (!(c = iptcc_find_label(chain, *handle))) {
DEBUGP("cannot find chain `%s'\n", chain);
errno = ENOENT;
return 0;
}
if (TC_BUILTIN(chain, *handle)) {
DEBUGP("cannot remove builtin chain `%s'\n", chain);
errno = EINVAL;
return 0;
}
if (!TC_GET_REFERENCES(&references, chain, handle)) {
DEBUGP("cannot get references on chain `%s'\n", chain);
return 0;
}
if (references > 0) {
DEBUGP("chain `%s' still has references\n", chain);
errno = EMLINK;
return 0;
}
if (c->num_rules) {
DEBUGP("chain `%s' is not empty\n", chain);
errno = ENOTEMPTY;
return 0;
}
/* If we are about to delete the chain that is the current
* iterator, move chain iterator firward. */
if (c == (*handle)->chain_iterator_cur)
iptcc_chain_iterator_advance(*handle);
list_del(&c->list);
free(c);
DEBUGP("chain `%s' deleted\n", chain);
set_changed(*handle);
return 1;
}
/* Renames a chain. */
int TC_RENAME_CHAIN(const IPT_CHAINLABEL oldname,
const IPT_CHAINLABEL newname,
TC_HANDLE_T *handle)
{
struct chain_head *c;
iptc_fn = TC_RENAME_CHAIN;
/* find_label doesn't cover built-in targets: DROP, ACCEPT,
QUEUE, RETURN. */
if (iptcc_find_label(newname, *handle)
|| strcmp(newname, LABEL_DROP) == 0
|| strcmp(newname, LABEL_ACCEPT) == 0
|| strcmp(newname, LABEL_QUEUE) == 0
|| strcmp(newname, LABEL_RETURN) == 0) {
errno = EEXIST;
return 0;
}
if (!(c = iptcc_find_label(oldname, *handle))
|| TC_BUILTIN(oldname, *handle)) {
errno = ENOENT;
return 0;
}
if (strlen(newname)+1 > sizeof(IPT_CHAINLABEL)) {
errno = EINVAL;
return 0;
}
strncpy(c->name, newname, sizeof(IPT_CHAINLABEL));
set_changed(*handle);
return 1;
}
/* Sets the policy on a built-in chain. */
int
TC_SET_POLICY(const IPT_CHAINLABEL chain,
const IPT_CHAINLABEL policy,
STRUCT_COUNTERS *counters,
TC_HANDLE_T *handle)
{
struct chain_head *c;
iptc_fn = TC_SET_POLICY;
if (!(c = iptcc_find_label(chain, *handle))) {
DEBUGP("cannot find chain `%s'\n", chain);
errno = ENOENT;
return 0;
}
if (!iptcc_is_builtin(c)) {
DEBUGP("cannot set policy of userdefinedchain `%s'\n", chain);
errno = ENOENT;
return 0;
}
if (strcmp(policy, LABEL_ACCEPT) == 0)
c->verdict = -NF_ACCEPT - 1;
else if (strcmp(policy, LABEL_DROP) == 0)
c->verdict = -NF_DROP - 1;
else {
errno = EINVAL;
return 0;
}
if (counters) {
/* set byte and packet counters */
memcpy(&c->counters, counters, sizeof(STRUCT_COUNTERS));
c->counter_map.maptype = COUNTER_MAP_SET;
} else {
c->counter_map.maptype = COUNTER_MAP_NOMAP;
}
set_changed(*handle);
return 1;
}
/* Without this, on gcc 2.7.2.3, we get:
libiptc.c: In function `TC_COMMIT':
libiptc.c:833: fixed or forbidden register was spilled.
This may be due to a compiler bug or to impossible asm
statements or clauses.
*/
static void
subtract_counters(STRUCT_COUNTERS *answer,
const STRUCT_COUNTERS *a,
const STRUCT_COUNTERS *b)
{
answer->pcnt = a->pcnt - b->pcnt;
answer->bcnt = a->bcnt - b->bcnt;
}
static void counters_nomap(STRUCT_COUNTERS_INFO *newcounters,
unsigned int index)
{
newcounters->counters[index] = ((STRUCT_COUNTERS) { 0, 0});
DEBUGP_C("NOMAP => zero\n");
}
static void counters_normal_map(STRUCT_COUNTERS_INFO *newcounters,
STRUCT_REPLACE *repl,
unsigned int index,
unsigned int mappos)
{
/* Original read: X.
* Atomic read on replacement: X + Y.
* Currently in kernel: Z.
* Want in kernel: X + Y + Z.
* => Add in X + Y
* => Add in replacement read.
*/
newcounters->counters[index] = repl->counters[mappos];
DEBUGP_C("NORMAL_MAP => mappos %u \n", mappos);
}
static void counters_map_zeroed(STRUCT_COUNTERS_INFO *newcounters,
STRUCT_REPLACE *repl,
unsigned int index,
unsigned int mappos,
STRUCT_COUNTERS *counters)
{
/* Original read: X.
* Atomic read on replacement: X + Y.
* Currently in kernel: Z.
* Want in kernel: Y + Z.
* => Add in Y.
* => Add in (replacement read - original read).
*/
subtract_counters(&newcounters->counters[index],
&repl->counters[mappos],
counters);
DEBUGP_C("ZEROED => mappos %u\n", mappos);
}
static void counters_map_set(STRUCT_COUNTERS_INFO *newcounters,
unsigned int index,
STRUCT_COUNTERS *counters)
{
/* Want to set counter (iptables-restore) */
memcpy(&newcounters->counters[index], counters,
sizeof(STRUCT_COUNTERS));
DEBUGP_C("SET\n");
}
int
TC_COMMIT(TC_HANDLE_T *handle)
{
/* Replace, then map back the counters. */
STRUCT_REPLACE *repl;
STRUCT_COUNTERS_INFO *newcounters;
struct chain_head *c;
int ret;
size_t counterlen;
int new_number;
unsigned int new_size;
iptc_fn = TC_COMMIT;
CHECK(*handle);
/* Don't commit if nothing changed. */
if (!(*handle)->changed)
goto finished;
new_number = iptcc_compile_table_prep(*handle, &new_size);
if (new_number < 0) {
errno = ENOMEM;
goto out_zero;
}
repl = malloc(sizeof(*repl) + new_size);
if (!repl) {
errno = ENOMEM;
goto out_zero;
}
memset(repl, 0, sizeof(*repl) + new_size);
#if 0
TC_DUMP_ENTRIES(*handle);
#endif
counterlen = sizeof(STRUCT_COUNTERS_INFO)
+ sizeof(STRUCT_COUNTERS) * new_number;
/* These are the old counters we will get from kernel */
repl->counters = malloc(sizeof(STRUCT_COUNTERS)
* (*handle)->info.num_entries);
if (!repl->counters) {
errno = ENOMEM;
goto out_free_repl;
}
/* These are the counters we're going to put back, later. */
newcounters = malloc(counterlen);
if (!newcounters) {
errno = ENOMEM;
goto out_free_repl_counters;
}
memset(newcounters, 0, counterlen);
strcpy(repl->name, (*handle)->info.name);
repl->num_entries = new_number;
repl->size = new_size;
repl->num_counters = (*handle)->info.num_entries;
repl->valid_hooks = (*handle)->info.valid_hooks;
DEBUGP("num_entries=%u, size=%u, num_counters=%u\n",
repl->num_entries, repl->size, repl->num_counters);
ret = iptcc_compile_table(*handle, repl);
if (ret < 0) {
errno = ret;
goto out_free_newcounters;
}
#ifdef IPTC_DEBUG2
{
int fd = open("/tmp/libiptc-so_set_replace.blob",
O_CREAT|O_WRONLY);
if (fd >= 0) {
write(fd, repl, sizeof(*repl) + repl->size);
close(fd);
}
}
#endif
ret = setsockopt(sockfd, TC_IPPROTO, SO_SET_REPLACE, repl,
sizeof(*repl) + repl->size);
if (ret < 0)
goto out_free_newcounters;
/* Put counters back. */
strcpy(newcounters->name, (*handle)->info.name);
newcounters->num_counters = new_number;
list_for_each_entry(c, &(*handle)->chains, list) {
struct rule_head *r;
/* Builtin chains have their own counters */
if (iptcc_is_builtin(c)) {
DEBUGP("counter for chain-index %u: ", c->foot_index);
switch(c->counter_map.maptype) {
case COUNTER_MAP_NOMAP:
counters_nomap(newcounters, c->foot_index);
break;
case COUNTER_MAP_NORMAL_MAP:
counters_normal_map(newcounters, repl,
c->foot_index,
c->counter_map.mappos);
break;
case COUNTER_MAP_ZEROED:
counters_map_zeroed(newcounters, repl,
c->foot_index,
c->counter_map.mappos,
&c->counters);
break;
case COUNTER_MAP_SET:
counters_map_set(newcounters, c->foot_index,
&c->counters);
break;
}
}
list_for_each_entry(r, &c->rules, list) {
DEBUGP("counter for index %u: ", r->index);
switch (r->counter_map.maptype) {
case COUNTER_MAP_NOMAP:
counters_nomap(newcounters, r->index);
break;
case COUNTER_MAP_NORMAL_MAP:
counters_normal_map(newcounters, repl,
r->index,
r->counter_map.mappos);
break;
case COUNTER_MAP_ZEROED:
counters_map_zeroed(newcounters, repl,
r->index,
r->counter_map.mappos,
&r->entry->counters);
break;
case COUNTER_MAP_SET:
counters_map_set(newcounters, r->index,
&r->entry->counters);
break;
}
}
}
#ifdef KERNEL_64_USERSPACE_32
{
/* Kernel will think that pointer should be 64-bits, and get
padding. So we accomodate here (assumption: alignment of
`counters' is on 64-bit boundary). */
u_int64_t *kernptr = (u_int64_t *)&newcounters->counters;
if ((unsigned long)&newcounters->counters % 8 != 0) {
fprintf(stderr,
"counters alignment incorrect! Mail rusty!\n");
abort();
}
*kernptr = newcounters->counters;
}
#endif /* KERNEL_64_USERSPACE_32 */
#ifdef IPTC_DEBUG2
{
int fd = open("/tmp/libiptc-so_set_add_counters.blob",
O_CREAT|O_WRONLY);
if (fd >= 0) {
write(fd, newcounters, counterlen);
close(fd);
}
}
#endif
ret = setsockopt(sockfd, TC_IPPROTO, SO_SET_ADD_COUNTERS,
newcounters, counterlen);
if (ret < 0)
goto out_free_newcounters;
free(repl->counters);
free(repl);
free(newcounters);
finished:
TC_FREE(handle);
return 1;
out_free_newcounters:
free(newcounters);
out_free_repl_counters:
free(repl->counters);
out_free_repl:
free(repl);
out_zero:
return 0;
}
/* Get raw socket. */
int
TC_GET_RAW_SOCKET()
{
return sockfd;
}
/* Translates errno numbers into more human-readable form than strerror. */
const char *
TC_STRERROR(int err)
{
unsigned int i;
struct table_struct {
void *fn;
int err;
const char *message;
} table [] =
{ { TC_INIT, EPERM, "Permission denied (you must be root)" },
{ TC_INIT, EINVAL, "Module is wrong version" },
{ TC_INIT, ENOENT,
"Table does not exist (do you need to insmod?)" },
{ TC_DELETE_CHAIN, ENOTEMPTY, "Chain is not empty" },
{ TC_DELETE_CHAIN, EINVAL, "Can't delete built-in chain" },
{ TC_DELETE_CHAIN, EMLINK,
"Can't delete chain with references left" },
{ TC_CREATE_CHAIN, EEXIST, "Chain already exists" },
{ TC_INSERT_ENTRY, E2BIG, "Index of insertion too big" },
{ TC_REPLACE_ENTRY, E2BIG, "Index of replacement too big" },
{ TC_DELETE_NUM_ENTRY, E2BIG, "Index of deletion too big" },
{ TC_READ_COUNTER, E2BIG, "Index of counter too big" },
{ TC_ZERO_COUNTER, E2BIG, "Index of counter too big" },
{ TC_INSERT_ENTRY, ELOOP, "Loop found in table" },
{ TC_INSERT_ENTRY, EINVAL, "Target problem" },
/* EINVAL for CHECK probably means bad interface. */
{ TC_CHECK_PACKET, EINVAL,
"Bad arguments (does that interface exist?)" },
{ TC_CHECK_PACKET, ENOSYS,
"Checking will most likely never get implemented" },
/* ENOENT for DELETE probably means no matching rule */
{ TC_DELETE_ENTRY, ENOENT,
"Bad rule (does a matching rule exist in that chain?)" },
{ TC_SET_POLICY, ENOENT,
"Bad built-in chain name" },
{ TC_SET_POLICY, EINVAL,
"Bad policy name" },
{ NULL, 0, "Incompatible with this kernel" },
{ NULL, ENOPROTOOPT, "iptables who? (do you need to insmod?)" },
{ NULL, ENOSYS, "Will be implemented real soon. I promise ;)" },
{ NULL, ENOMEM, "Memory allocation problem" },
{ NULL, ENOENT, "No chain/target/match by that name" },
};
for (i = 0; i < sizeof(table)/sizeof(struct table_struct); i++) {
if ((!table[i].fn || table[i].fn == iptc_fn)
&& table[i].err == err)
return table[i].message;
}
return strerror(err);
}