ip6_tables.c

该文件是rt_linux

	if (ret != 0) {
		IP6T_ENTRY_ITERATE(newinfo->entries, newinfo->size,
				  cleanup_entry, &i);
		return ret;
	}

	/* And one copy for every other CPU */
	for (i = 1; i < smp_num_cpus; i++) {
		memcpy(newinfo->entries + SMP_ALIGN(newinfo->size)*i,
		       newinfo->entries,
		       SMP_ALIGN(newinfo->size));
	}

	return ret;
}

static struct ip6t_table_info *
replace_table(struct ip6t_table *table,
	      unsigned int num_counters,
	      struct ip6t_table_info *newinfo,
	      int *error)
{
	struct ip6t_table_info *oldinfo;

#ifdef CONFIG_NETFILTER_DEBUG
	{
		struct ip6t_entry *table_base;
		unsigned int i;

		for (i = 0; i < smp_num_cpus; i++) {
			table_base =
				(void *)newinfo->entries
				+ TABLE_OFFSET(newinfo, i);

			table_base->comefrom = 0xdead57ac;
		}
	}
#endif

	/* Do the substitution. */
	write_lock_bh(&table->lock);
	/* Check inside lock: is the old number correct? */
	if (num_counters != table->private->number) {
		duprintf("num_counters != table->private->number (%u/%u)\n",
			 num_counters, table->private->number);
		write_unlock_bh(&table->lock);
		*error = -EAGAIN;
		return NULL;
	}
	oldinfo = table->private;
	table->private = newinfo;
	newinfo->initial_entries = oldinfo->initial_entries;
	write_unlock_bh(&table->lock);

	return oldinfo;
}

/* Gets counters. */
static inline int
add_entry_to_counter(const struct ip6t_entry *e,
		     struct ip6t_counters total[],
		     unsigned int *i)
{
	ADD_COUNTER(total[*i], e->counters.bcnt, e->counters.pcnt);

	(*i)++;
	return 0;
}

static void
get_counters(const struct ip6t_table_info *t,
	     struct ip6t_counters counters[])
{
	unsigned int cpu;
	unsigned int i;

	for (cpu = 0; cpu < smp_num_cpus; cpu++) {
		i = 0;
		IP6T_ENTRY_ITERATE(t->entries + TABLE_OFFSET(t, cpu),
				  t->size,
				  add_entry_to_counter,
				  counters,
				  &i);
	}
}

static int
copy_entries_to_user(unsigned int total_size,
		     struct ip6t_table *table,
		     void *userptr)
{
	unsigned int off, num, countersize;
	struct ip6t_entry *e;
	struct ip6t_counters *counters;
	int ret = 0;

	/* We need atomic snapshot of counters: rest doesn't change
	   (other than comefrom, which userspace doesn't care
	   about). */
	countersize = sizeof(struct ip6t_counters) * table->private->number;
	counters = vmalloc(countersize);

	if (counters == NULL)
		return -ENOMEM;

	/* First, sum counters... */
	memset(counters, 0, countersize);
	write_lock_bh(&table->lock);
	get_counters(table->private, counters);
	write_unlock_bh(&table->lock);

	/* ... then copy entire thing from CPU 0... */
	if (copy_to_user(userptr, table->private->entries, total_size) != 0) {
		ret = -EFAULT;
		goto free_counters;
	}

	/* FIXME: use iterator macros --RR */
	/* ... then go back and fix counters and names */
	for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
		unsigned int i;
		struct ip6t_entry_match *m;
		struct ip6t_entry_target *t;

		e = (struct ip6t_entry *)(table->private->entries + off);
		if (copy_to_user(userptr + off
				 + offsetof(struct ip6t_entry, counters),
				 &counters[num],
				 sizeof(counters[num])) != 0) {
			ret = -EFAULT;
			goto free_counters;
		}

		for (i = sizeof(struct ip6t_entry);
		     i < e->target_offset;
		     i += m->u.match_size) {
			m = (void *)e + i;

			if (copy_to_user(userptr + off + i
					 + offsetof(struct ip6t_entry_match,
						    u.user.name),
					 m->u.kernel.match->name,
					 strlen(m->u.kernel.match->name)+1)
			    != 0) {
				ret = -EFAULT;
				goto free_counters;
			}
		}

		t = ip6t_get_target(e);
		if (copy_to_user(userptr + off + e->target_offset
				 + offsetof(struct ip6t_entry_target,
					    u.user.name),
				 t->u.kernel.target->name,
				 strlen(t->u.kernel.target->name)+1) != 0) {
			ret = -EFAULT;
			goto free_counters;
		}
	}

 free_counters:
	vfree(counters);
	return ret;
}

static int
get_entries(const struct ip6t_get_entries *entries,
	    struct ip6t_get_entries *uptr)
{
	int ret;
	struct ip6t_table *t;

	t = find_table_lock(entries->name, &ret, &ip6t_mutex);
	if (t) {
		duprintf("t->private->number = %u\n",
			 t->private->number);
		if (entries->size == t->private->size)
			ret = copy_entries_to_user(t->private->size,
						   t, uptr->entrytable);
		else {
			duprintf("get_entries: I've got %u not %u!\n",
				 t->private->size,
				 entries->size);
			ret = -EINVAL;
		}
		up(&ip6t_mutex);
	} else
		duprintf("get_entries: Can't find %s!\n",
			 entries->name);

	return ret;
}

static int
do_replace(void *user, unsigned int len)
{
	int ret;
	struct ip6t_replace tmp;
	struct ip6t_table *t;
	struct ip6t_table_info *newinfo, *oldinfo;
	struct ip6t_counters *counters;

	if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
		return -EFAULT;

	/* Pedantry: prevent them from hitting BUG() in vmalloc.c --RR */
	if ((SMP_ALIGN(tmp.size) >> PAGE_SHIFT) + 2 > num_physpages)
		return -ENOMEM;

	newinfo = vmalloc(sizeof(struct ip6t_table_info)
			  + SMP_ALIGN(tmp.size) * smp_num_cpus);
	if (!newinfo)
		return -ENOMEM;

	if (copy_from_user(newinfo->entries, user + sizeof(tmp),
			   tmp.size) != 0) {
		ret = -EFAULT;
		goto free_newinfo;
	}

	counters = vmalloc(tmp.num_counters * sizeof(struct ip6t_counters));
	if (!counters) {
		ret = -ENOMEM;
		goto free_newinfo;
	}
	memset(counters, 0, tmp.num_counters * sizeof(struct ip6t_counters));

	ret = translate_table(tmp.name, tmp.valid_hooks,
			      newinfo, tmp.size, tmp.num_entries,
			      tmp.hook_entry, tmp.underflow);
	if (ret != 0)
		goto free_newinfo_counters;

	duprintf("ip_tables: Translated table\n");

	t = find_table_lock(tmp.name, &ret, &ip6t_mutex);
	if (!t)
		goto free_newinfo_counters_untrans;

	/* You lied! */
	if (tmp.valid_hooks != t->valid_hooks) {
		duprintf("Valid hook crap: %08X vs %08X\n",
			 tmp.valid_hooks, t->valid_hooks);
		ret = -EINVAL;
		goto free_newinfo_counters_untrans_unlock;
	}

	oldinfo = replace_table(t, tmp.num_counters, newinfo, &ret);
	if (!oldinfo)
		goto free_newinfo_counters_untrans_unlock;

	/* Update module usage count based on number of rules */
	duprintf("do_replace: oldnum=%u, initnum=%u, newnum=%u\n",
		oldinfo->number, oldinfo->initial_entries, newinfo->number);
	if (t->me && (oldinfo->number <= oldinfo->initial_entries) &&
 	    (newinfo->number > oldinfo->initial_entries))
		__MOD_INC_USE_COUNT(t->me);
	else if (t->me && (oldinfo->number > oldinfo->initial_entries) &&
	 	 (newinfo->number <= oldinfo->initial_entries))
		__MOD_DEC_USE_COUNT(t->me);

	/* Get the old counters. */
	get_counters(oldinfo, counters);
	/* Decrease module usage counts and free resource */
	IP6T_ENTRY_ITERATE(oldinfo->entries, oldinfo->size, cleanup_entry,NULL);
	vfree(oldinfo);
	/* Silent error: too late now. */
	copy_to_user(tmp.counters, counters,
		     sizeof(struct ip6t_counters) * tmp.num_counters);
	vfree(counters);
	up(&ip6t_mutex);
	return 0;

 free_newinfo_counters_untrans_unlock:
	up(&ip6t_mutex);
 free_newinfo_counters_untrans:
	IP6T_ENTRY_ITERATE(newinfo->entries, newinfo->size, cleanup_entry,NULL);
 free_newinfo_counters:
	vfree(counters);
 free_newinfo:
	vfree(newinfo);
	return ret;
}

/* We're lazy, and add to the first CPU; overflow works its fey magic
 * and everything is OK. */
static inline int
add_counter_to_entry(struct ip6t_entry *e,
		     const struct ip6t_counters addme[],
		     unsigned int *i)
{
#if 0
	duprintf("add_counter: Entry %u %lu/%lu + %lu/%lu\n",
		 *i,
		 (long unsigned int)e->counters.pcnt,
		 (long unsigned int)e->counters.bcnt,
		 (long unsigned int)addme[*i].pcnt,
		 (long unsigned int)addme[*i].bcnt);
#endif

	ADD_COUNTER(e->counters, addme[*i].bcnt, addme[*i].pcnt);

	(*i)++;
	return 0;
}

static int
do_add_counters(void *user, unsigned int len)
{
	unsigned int i;
	struct ip6t_counters_info tmp, *paddc;
	struct ip6t_table *t;
	int ret;

	if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
		return -EFAULT;

	if (len != sizeof(tmp) + tmp.num_counters*sizeof(struct ip6t_counters))
		return -EINVAL;

	paddc = vmalloc(len);
	if (!paddc)
		return -ENOMEM;

	if (copy_from_user(paddc, user, len) != 0) {
		ret = -EFAULT;
		goto free;
	}

	t = find_table_lock(tmp.name, &ret, &ip6t_mutex);
	if (!t)
		goto free;

	write_lock_bh(&t->lock);
	if (t->private->number != paddc->num_counters) {
		ret = -EINVAL;
		goto unlock_up_free;
	}

	i = 0;
	IP6T_ENTRY_ITERATE(t->private->entries,
			  t->private->size,
			  add_counter_to_entry,
			  paddc->counters,
			  &i);
 unlock_up_free:
	write_unlock_bh(&t->lock);
	up(&ip6t_mutex);
 free:
	vfree(paddc);

	return ret;
}

static int
do_ip6t_set_ctl(struct sock *sk,	int cmd, void *user, unsigned int len)
{
	int ret;

	if (!capable(CAP_NET_ADMIN))
		return -EPERM;

	switch (cmd) {
	case IP6T_SO_SET_REPLACE:
		ret = do_replace(user, len);
		break;

	case IP6T_SO_SET_ADD_COUNTERS:
		ret = do_add_counters(user, len);
		break;

	default:
		duprintf("do_ip6t_set_ctl:  unknown request %i\n", cmd);
		ret = -EINVAL;
	}

	return ret;
}

static int
do_ip6t_get_ctl(struct sock *sk, int cmd, void *user, int *len)
{
	int ret;

	if (!capable(CAP_NET_ADMIN))
		return -EPERM;

	switch (cmd) {
	case IP6T_SO_GET_INFO: {
		char name[IP6T_TABLE_MAXNAMELEN];
		struct ip6t_table *t;

		if (*len != sizeof(struct ip6t_getinfo)) {
			duprintf("length %u != %u\n", *len,
				 sizeof(struct ip6t_getinfo));
			ret = -EINVAL;
			break;
		}

		if (copy_from_user(name, user, sizeof(name)) != 0) {
			ret = -EFAULT;
			break;
		}
		name[IP6T_TABLE_MAXNAMELEN-1] = '\0';
		t = find_table_lock(name, &ret, &ip6t_mutex);
		if (t) {
			struct ip6t_getinfo info;

			info.valid_hooks = t->valid_hooks;
			memcpy(info.hook_entry, t->private->hook_entry,
			       sizeof(info.hook_entry));
			memcpy(info.underflow, t->private->underflow,
			       sizeof(info.underflow));
			info.num_entries = t->private->number;
			info.size = t->private->size;
			strcpy(info.name, name);

			if (copy_to_user(user, &info, *len) != 0)
				ret = -EFAULT;
			else
				ret = 0;

			up(&ip6t_mutex);
		}
	}
	break;

	case IP6T_SO_GET_ENTRIES: {
		struct ip6t_get_entries get;

		if (*len < sizeof(get)) {
			duprintf("get_entries: %u < %u\n", *len, sizeof(get));
			ret = -EINVAL;
		} else if (copy_from_user(&get, user, sizeof(get)) != 0) {
			ret = -EFAULT;
		} else if (*len != sizeof(struct ip6t_get_entries) + get.size) {
			duprintf("get_entries: %u != %u\n", *len,
				 sizeof(struct ip6t_get_entries) + get.size);
			ret = -EINVAL;
		} else
			ret = get_entries(&get, user);
		break;
	}

	default:
		duprintf("do_ip6t_get_ctl: unknown request %i\n", cmd);
		ret = -EINVAL;
	}

	return ret;
}

/* Registration hooks for targets. */
int
ip6t_register_target(struct ip6t_target *target)
{
	int ret;

	MOD_INC_USE_COUNT;
	ret = down_interruptible(&ip6t_mutex);
	if (ret != 0) {
		MOD_DEC_USE_COUNT;
		return ret;
	}
	if (!list_named_insert(&ip6t_target, target)) {