src/callback.c

/*
 * (C) 2005-2011 by Pablo Neira Ayuso <pablo@netfilter.org>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#include "internal/internal.h"

static int __parse_message(const struct nlmsghdr *nlh)
{
	uint16_t type = NFNL_MSG_TYPE(nlh->nlmsg_type);
	uint16_t flags = nlh->nlmsg_flags;
	int ret = NFCT_T_UNKNOWN;

	switch(type) {
	case IPCTNL_MSG_CT_NEW: /* same value for IPCTNL_MSG_EXP_NEW. */
		if (flags & (NLM_F_CREATE|NLM_F_EXCL))
			ret = NFCT_T_NEW;
		else
			ret = NFCT_T_UPDATE;
		break;
	case IPCTNL_MSG_CT_DELETE: /* same value for IPCTNL_MSG_EXP_DELETE. */
		ret = NFCT_T_DESTROY;
		break;
	}
	return ret;
}

int __callback(struct nlmsghdr *nlh, struct nfattr *nfa[], void *data)
{
	int ret = NFNL_CB_STOP;
	unsigned int type;
	struct nf_conntrack *ct = NULL;
	struct nf_expect *exp = NULL;
	struct __data_container *container = data;
	uint8_t subsys = NFNL_SUBSYS_ID(nlh->nlmsg_type);

	if (nlh->nlmsg_len < NLMSG_LENGTH(sizeof(struct nfgenmsg))) {
		errno = EINVAL;
		return NFNL_CB_FAILURE;
	}
	type = __parse_message(nlh);
	if (!(type & container->type))
		return NFNL_CB_CONTINUE;

	switch(subsys) {
	case NFNL_SUBSYS_CTNETLINK:
		ct = nfct_new();
		if (ct == NULL)
			return NFNL_CB_FAILURE;

		__parse_conntrack(nlh, nfa, ct);

		if (container->h->cb) {
			ret = container->h->cb(type, ct, container->data);
		} else if (container->h->cb2) {
			ret = container->h->cb2(nlh, type, ct,
						container->data);
		}
		break;
	case NFNL_SUBSYS_CTNETLINK_EXP:
		exp = nfexp_new();
		if (exp == NULL)
			return NFNL_CB_FAILURE;

		__parse_expect(nlh, nfa, exp);

		if (container->h->expect_cb) {
			ret = container->h->expect_cb(type, exp,
						      container->data);
		} else if (container->h->expect_cb2) {
			ret = container->h->expect_cb2(nlh, type, exp,
						       container->data);
		}
		break;
	default:
		errno = ENOTSUP;
		ret = NFNL_CB_FAILURE;
		break;
	}

	if (ret == NFCT_CB_STOLEN)
		return NFNL_CB_CONTINUE;

	if (ct)
		nfct_destroy(ct);
	if (exp)
		nfexp_destroy(exp);

	return ret;
}