nlmsg.c

/*
 * (C) 2012 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 <arpa/inet.h>
#include <time.h>
#include <endian.h>
#include <stdlib.h>
#include <string.h>

#include <libmnl/libmnl.h>

#ifndef __aligned_be64
#define __aligned_be64 __be64 __attribute__((aligned(8)))
#define __aligned_le64 __le64 __attribute__((aligned(8)))
#endif

#include <linux/netfilter/nfnetlink_queue.h>

#include <libnetfilter_queue/libnetfilter_queue.h>

#include "internal.h"

EXPORT_SYMBOL
void nfq_nlmsg_verdict_put(struct nlmsghdr *nlh, int id, int verdict)
{
        struct nfqnl_msg_verdict_hdr vh = {
                .verdict        = htonl(verdict),
                .id             = htonl(id),
        };
        mnl_attr_put(nlh, NFQA_VERDICT_HDR, sizeof(vh), &vh);
}

EXPORT_SYMBOL
void nfq_nlmsg_verdict_put_mark(struct nlmsghdr *nlh, uint32_t mark)
{
        mnl_attr_put_u32(nlh, NFQA_MARK, htonl(mark));
}

EXPORT_SYMBOL
void nfq_nlmsg_verdict_put_pkt(struct nlmsghdr *nlh, const void *pkt,
                               uint32_t plen)
{
        mnl_attr_put(nlh, NFQA_PAYLOAD, plen, pkt);
}

EXPORT_SYMBOL
void nfq_nlmsg_cfg_put_cmd(struct nlmsghdr *nlh, uint16_t pf, uint8_t cmd)
{
        struct nfqnl_msg_config_cmd command = {
                .command = cmd,
                .pf = htons(pf),
        };
        mnl_attr_put(nlh, NFQA_CFG_CMD, sizeof(command), &command);
}

EXPORT_SYMBOL
void nfq_nlmsg_cfg_put_params(struct nlmsghdr *nlh, uint8_t mode, int range)
{
        struct nfqnl_msg_config_params params = {
                .copy_range = htonl(range),
                .copy_mode = mode,
        };
        mnl_attr_put(nlh, NFQA_CFG_PARAMS, sizeof(params), &params);
}

EXPORT_SYMBOL
void nfq_nlmsg_cfg_put_qmaxlen(struct nlmsghdr *nlh, uint32_t queue_maxlen)
{
        mnl_attr_put_u32(nlh, NFQA_CFG_QUEUE_MAXLEN, htonl(queue_maxlen));
}

static int nfq_pkt_parse_attr_cb(const struct nlattr *attr, void *data)
{
        const struct nlattr **tb = data;
        int type = mnl_attr_get_type(attr);

        /* skip unsupported attribute in user-space */
        if (mnl_attr_type_valid(attr, NFQA_MAX) < 0)
                return MNL_CB_OK;

        switch(type) {
        case NFQA_MARK:
        case NFQA_IFINDEX_INDEV:
        case NFQA_IFINDEX_OUTDEV:
        case NFQA_IFINDEX_PHYSINDEV:
        case NFQA_IFINDEX_PHYSOUTDEV:
        case NFQA_CAP_LEN:
        case NFQA_SKB_INFO:
        case NFQA_SECCTX:
        case NFQA_UID:
        case NFQA_GID:
        case NFQA_CT_INFO:
                if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
                        return MNL_CB_ERROR;
                break;
        case NFQA_TIMESTAMP:
                if (mnl_attr_validate2(attr, MNL_TYPE_UNSPEC,
                    sizeof(struct nfqnl_msg_packet_timestamp)) < 0) {
                        return MNL_CB_ERROR;
                }
                break;
        case NFQA_HWADDR:
                if (mnl_attr_validate2(attr, MNL_TYPE_UNSPEC,
                    sizeof(struct nfqnl_msg_packet_hw)) < 0) {
                        return MNL_CB_ERROR;
                }
                break;
        case NFQA_PACKET_HDR:
                if (mnl_attr_validate2(attr, MNL_TYPE_UNSPEC,
                    sizeof(struct nfqnl_msg_packet_hdr)) < 0) {
                        return MNL_CB_ERROR;
                }
                break;
        case NFQA_PAYLOAD:
        case NFQA_CT:
        case NFQA_EXP:
                break;
        }
        tb[type] = attr;
        return MNL_CB_OK;
}

EXPORT_SYMBOL
int nfq_nlmsg_parse(const struct nlmsghdr *nlh, struct nlattr **attr)
{
        return mnl_attr_parse(nlh, sizeof(struct nfgenmsg),
                              nfq_pkt_parse_attr_cb, attr);
}

EXPORT_SYMBOL
struct nlmsghdr *nfq_nlmsg_put(char *buf, int type, uint32_t queue_num)
{
        struct nlmsghdr *nlh = mnl_nlmsg_put_header(buf);
        nlh->nlmsg_type = (NFNL_SUBSYS_QUEUE << 8) | type;
        nlh->nlmsg_flags = NLM_F_REQUEST;

        struct nfgenmsg *nfg = mnl_nlmsg_put_extra_header(nlh, sizeof(*nfg));
        nfg->nfgen_family = AF_UNSPEC;
        nfg->version = NFNETLINK_V0;
        nfg->res_id = htons(queue_num);

        return nlh;
}