libnetfilter_cttimeout.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.
 *
 * This code has been sponsored by Vyatta Inc. <http://www.vyatta.com>
 */
#include "internal.h"

#include <time.h>
#include <endian.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <netinet/in.h>

#include <libmnl/libmnl.h>
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nfnetlink_cttimeout.h>

#include <libnetfilter_cttimeout/libnetfilter_cttimeout.h>

static const char *const tcp_state_to_name[] = {
        [NFCT_TIMEOUT_ATTR_TCP_SYN_SENT]        = "SYN_SENT",
        [NFCT_TIMEOUT_ATTR_TCP_SYN_RECV]        = "SYN_RECV",
        [NFCT_TIMEOUT_ATTR_TCP_ESTABLISHED]     = "ESTABLISHED",
        [NFCT_TIMEOUT_ATTR_TCP_FIN_WAIT]        = "FIN_WAIT",
        [NFCT_TIMEOUT_ATTR_TCP_CLOSE_WAIT]      = "CLOSE_WAIT",
        [NFCT_TIMEOUT_ATTR_TCP_LAST_ACK]        = "LAST_ACK",
        [NFCT_TIMEOUT_ATTR_TCP_TIME_WAIT]       = "TIME_WAIT",
        [NFCT_TIMEOUT_ATTR_TCP_CLOSE]           = "CLOSE",
        [NFCT_TIMEOUT_ATTR_TCP_SYN_SENT2]       = "SYN_SENT2",
        [NFCT_TIMEOUT_ATTR_TCP_RETRANS]         = "RETRANS",
        [NFCT_TIMEOUT_ATTR_TCP_UNACK]           = "UNACKNOWLEDGED",
};

static const char *const generic_state_to_name[] = {
        [NFCT_TIMEOUT_ATTR_GENERIC]             = "TIMEOUT",
};

static const char *const udp_state_to_name[] = {
        [NFCT_TIMEOUT_ATTR_UDP_UNREPLIED]       = "UNREPLIED",
        [NFCT_TIMEOUT_ATTR_UDP_REPLIED]         = "REPLIED",
};

static const char *const sctp_state_to_name[] = {
        [NFCT_TIMEOUT_ATTR_SCTP_CLOSED]                 = "CLOSED",
        [NFCT_TIMEOUT_ATTR_SCTP_COOKIE_WAIT]            = "COOKIE_WAIT",
        [NFCT_TIMEOUT_ATTR_SCTP_COOKIE_ECHOED]          = "COOKIE_ECHOED",
        [NFCT_TIMEOUT_ATTR_SCTP_ESTABLISHED]            = "ESTABLISHED",
        [NFCT_TIMEOUT_ATTR_SCTP_SHUTDOWN_SENT]          = "SHUTDOWN_SENT",
        [NFCT_TIMEOUT_ATTR_SCTP_SHUTDOWN_RECD]          = "SHUTDOWN_RECD",
        [NFCT_TIMEOUT_ATTR_SCTP_SHUTDOWN_ACK_SENT]      = "SHUTDOWN_ACK_SENT",
};

static const char *const dccp_state_to_name[] = {
        [NFCT_TIMEOUT_ATTR_DCCP_REQUEST]        = "REQUEST",
        [NFCT_TIMEOUT_ATTR_DCCP_RESPOND]        = "RESPOND",
        [NFCT_TIMEOUT_ATTR_DCCP_PARTOPEN]       = "PARTOPEN",
        [NFCT_TIMEOUT_ATTR_DCCP_OPEN]           = "OPEN",
        [NFCT_TIMEOUT_ATTR_DCCP_CLOSEREQ]       = "CLOSEREQ",
        [NFCT_TIMEOUT_ATTR_DCCP_CLOSING]        = "CLOSING",
        [NFCT_TIMEOUT_ATTR_DCCP_TIMEWAIT]       = "TIMEWAIT",
};

static const char *const icmp_state_to_name[] = {
        [NFCT_TIMEOUT_ATTR_ICMP]                = "TIMEOUT",
};

static const char *const icmpv6_state_to_name[] = {
        [NFCT_TIMEOUT_ATTR_ICMPV6]              = "TIMEOUT",
};

static struct {
        uint32_t nlattr_max;
        uint32_t attr_max;
        const char *const *state_to_name;
} timeout_protocol[IPPROTO_MAX] = {
        [IPPROTO_ICMP]  = {
                .nlattr_max     = __CTA_TIMEOUT_ICMP_MAX,
                .attr_max       = NFCT_TIMEOUT_ATTR_ICMP_MAX,
                .state_to_name  = icmp_state_to_name,
        },
        [IPPROTO_TCP]   = {
                .nlattr_max     = __CTA_TIMEOUT_TCP_MAX,
                .attr_max       = NFCT_TIMEOUT_ATTR_TCP_MAX,
                .state_to_name  = tcp_state_to_name,
        },
        [IPPROTO_UDP]   = {
                .nlattr_max     = __CTA_TIMEOUT_UDP_MAX,
                .attr_max       = NFCT_TIMEOUT_ATTR_UDP_MAX,
                .state_to_name  = udp_state_to_name,
        },
        [IPPROTO_GRE]   = {
                .nlattr_max     = __CTA_TIMEOUT_GRE_MAX,
                .attr_max       = NFCT_TIMEOUT_ATTR_GRE_MAX,
                .state_to_name  = udp_state_to_name,
        },
        [IPPROTO_SCTP]  = {
                .nlattr_max     = __CTA_TIMEOUT_SCTP_MAX,
                .attr_max       = NFCT_TIMEOUT_ATTR_SCTP_MAX,
                .state_to_name  = sctp_state_to_name,
        },
        [IPPROTO_DCCP]  = {
                .nlattr_max     = __CTA_TIMEOUT_DCCP_MAX,
                .attr_max       = NFCT_TIMEOUT_ATTR_DCCP_MAX,
                .state_to_name  = dccp_state_to_name,
        },
        [IPPROTO_UDPLITE]       = {
                .nlattr_max     = __CTA_TIMEOUT_UDPLITE_MAX,
                .attr_max       = NFCT_TIMEOUT_ATTR_UDPLITE_MAX,
                .state_to_name  = udp_state_to_name,
        },
        [IPPROTO_ICMPV6]        = {
                .nlattr_max     = __CTA_TIMEOUT_ICMPV6_MAX,
                .attr_max       = NFCT_TIMEOUT_ATTR_ICMPV6_MAX,
                .state_to_name  = icmpv6_state_to_name,
        },
        /* add your new supported protocol tracker here. */
        [IPPROTO_RAW]   = {
                .nlattr_max     = __CTA_TIMEOUT_GENERIC_MAX,
                .attr_max       = NFCT_TIMEOUT_ATTR_GENERIC_MAX,
                .state_to_name  = generic_state_to_name,
        },
};


struct nfct_timeout {
        char                            name[32];       /* object name. */
        uint16_t                        l3num;          /* AF_INET, ... */
        uint8_t                         l4num;          /* UDP, TCP, ... */
        uint16_t                        attrset;

        uint32_t                        *timeout;       /* array of timeout. */
        uint16_t                        polset;
};

struct nfct_timeout *nfct_timeout_alloc(void)
{
        struct nfct_timeout *t;

        t = calloc(1, sizeof(struct nfct_timeout));
        if (t == NULL)
                return NULL;

        return t;
}
EXPORT_SYMBOL(nfct_timeout_alloc);

void nfct_timeout_free(struct nfct_timeout *t)
{
        if (t->timeout)
                free(t->timeout);
        free(t);
}
EXPORT_SYMBOL(nfct_timeout_free);

int
nfct_timeout_attr_set(struct nfct_timeout *t, uint32_t type, const void *data)
{
        switch(type) {
        case NFCT_TIMEOUT_ATTR_NAME:
                strncpy(t->name, data, sizeof(t->name));
                t->name[sizeof(t->name)-1] = '\0';
                break;
        case NFCT_TIMEOUT_ATTR_L3PROTO:
                t->l3num = *((uint16_t *) data);
                break;
        case NFCT_TIMEOUT_ATTR_L4PROTO:
                t->l4num = *((uint8_t *) data);
                break;
        /* NFCT_TIMEOUT_ATTR_POLICY is set by nfct_timeout_policy_attr_set. */
        }
        t->attrset |= (1 << type);
        return 0;
}
EXPORT_SYMBOL(nfct_timeout_attr_set);

int
nfct_timeout_attr_set_u8(struct nfct_timeout *t, uint32_t type, uint8_t data)
{
        return nfct_timeout_attr_set(t, type, &data);
}
EXPORT_SYMBOL(nfct_timeout_attr_set_u8);

int
nfct_timeout_attr_set_u16(struct nfct_timeout *t, uint32_t type, uint16_t data)
{
        return nfct_timeout_attr_set(t, type, &data);
}
EXPORT_SYMBOL(nfct_timeout_attr_set_u16);

void nfct_timeout_attr_unset(struct nfct_timeout *t, uint32_t type)
{
        t->attrset &= ~(1 << type);
}
EXPORT_SYMBOL(nfct_timeout_attr_unset);

int
nfct_timeout_policy_attr_set_u32(struct nfct_timeout *t,
                                 uint32_t type, uint32_t data)
{
        size_t timeout_array_size;

        /* Layer 4 protocol needs to be already set. */
        if (!(t->attrset & (1 << NFCT_TIMEOUT_ATTR_L4PROTO)))
                return -1;

        if (t->timeout == NULL) {
                /* if not supported, default to generic protocol tracker. */
                if (timeout_protocol[t->l4num].attr_max != 0) {
                        timeout_array_size =
                                sizeof(uint32_t) *
                                        timeout_protocol[t->l4num].attr_max;
                } else {
                        timeout_array_size =
                                sizeof(uint32_t) *
                                        timeout_protocol[IPPROTO_RAW].attr_max;
                }
                t->timeout = calloc(1, timeout_array_size);
                if (t->timeout == NULL)
                        return -1;
        }

        /* this state does not exists in this protocol tracker. */
        if (type > timeout_protocol[t->l4num].attr_max)
                return -1;

        t->timeout[type] = data;
        t->polset |= (1 << type);

        if (!(t->attrset & (1 << NFCT_TIMEOUT_ATTR_POLICY)))
                t->attrset |= (1 << NFCT_TIMEOUT_ATTR_POLICY);

        return 0;
}
EXPORT_SYMBOL(nfct_timeout_policy_attr_set_u32);

void nfct_timeout_policy_attr_unset(struct nfct_timeout *t, uint32_t type)
{
        t->attrset &= ~(1 << type);
}
EXPORT_SYMBOL(nfct_timeout_policy_attr_unset);

const char *nfct_timeout_policy_attr_to_name(uint8_t l4proto, uint32_t state)
{
        if (timeout_protocol[l4proto].state_to_name == NULL) {
                printf("no array state name\n");
                return NULL;
        }

        if (timeout_protocol[l4proto].state_to_name[state] == NULL) {
                printf("state %d does not exists\n", state);
                return NULL;
        }

        return timeout_protocol[l4proto].state_to_name[state];
}
EXPORT_SYMBOL(nfct_timeout_policy_attr_to_name);

static int
nfct_timeout_snprintf_default(char *buf, size_t size,
                              const struct nfct_timeout *t,
                              unsigned int flags)
{
        int ret = 0;
        unsigned int offset = 0;

        if (t->attrset & (1 << NFCT_TIMEOUT_ATTR_NAME)) {
                ret = snprintf(buf+offset, size, ".%s = {\n", t->name);
                offset += ret;
                size -= ret;
        }
        if (t->attrset & (1 << NFCT_TIMEOUT_ATTR_L3PROTO)) {
                ret = snprintf(buf+offset, size, "\t.l3proto = %u,\n",
                                t->l3num);
                offset += ret;
                size -= ret;
        }
        if (t->attrset & (1 << NFCT_TIMEOUT_ATTR_L4PROTO)) {
                ret = snprintf(buf+offset, size, "\t.l4proto = %u,\n",
                                t->l4num);
                offset += ret;
                size -= ret;
        }
        if (t->attrset & (1 << NFCT_TIMEOUT_ATTR_POLICY)) {
                uint8_t l4num = t->l4num;
                int i;

                /* default to generic protocol tracker. */
                if (timeout_protocol[t->l4num].attr_max == 0)
                        l4num = IPPROTO_RAW;

                ret = snprintf(buf+offset, size, "\t.policy = {\n");
                offset += ret;
                size -= ret;

                for (i=0; i<timeout_protocol[l4num].attr_max; i++) {
                        const char *state_name =
                                timeout_protocol[l4num].state_to_name[i][0] ?
                                timeout_protocol[l4num].state_to_name[i] :
                                "UNKNOWN";

                        ret = snprintf(buf+offset, size,
                                "\t\t.%s = %u,\n", state_name, t->timeout[i]);
                        offset += ret;
                        size -= ret;
                }

                ret = snprintf(buf+offset, size, "\t},\n");
                offset += ret;
                size -= ret;
        }
        ret = snprintf(buf+offset, size, "};");
        offset += ret;
        size -= ret;

        buf[offset]='\0';

        return ret;
}

int nfct_timeout_snprintf(char *buf, size_t size, const struct nfct_timeout *t,
                          unsigned int type, unsigned int flags)
{
        int ret = 0;

        switch(type) {
        case NFCT_TIMEOUT_O_DEFAULT:
                ret = nfct_timeout_snprintf_default(buf, size, t, flags);
                break;
        /* add your new output here. */
        default:
                break;
        }

        return ret;
}
EXPORT_SYMBOL(nfct_timeout_snprintf);

struct nlmsghdr *
nfct_timeout_nlmsg_build_hdr(char *buf, uint8_t cmd,
                             uint16_t flags, uint32_t seq)
{
        struct nlmsghdr *nlh;
        struct nfgenmsg *nfh;

        nlh = mnl_nlmsg_put_header(buf);
        nlh->nlmsg_type = (NFNL_SUBSYS_CTNETLINK_TIMEOUT << 8) | cmd;
        nlh->nlmsg_flags = NLM_F_REQUEST | flags;
        nlh->nlmsg_seq = seq;

        nfh = mnl_nlmsg_put_extra_header(nlh, sizeof(struct nfgenmsg));
        nfh->nfgen_family = AF_UNSPEC;
        nfh->version = NFNETLINK_V0;
        nfh->res_id = 0;

        return nlh;
}
EXPORT_SYMBOL(nfct_timeout_nlmsg_build_hdr);

void
nfct_timeout_nlmsg_build_payload(struct nlmsghdr *nlh,
                                 const struct nfct_timeout *t)
{
        int i;
        struct nlattr *nest;

        if (t->attrset & (1 << NFCT_TIMEOUT_ATTR_NAME))
                mnl_attr_put_strz(nlh, CTA_TIMEOUT_NAME, t->name);

        if (t->attrset & (1 << NFCT_TIMEOUT_ATTR_L3PROTO))
                mnl_attr_put_u16(nlh, CTA_TIMEOUT_L3PROTO, htons(t->l3num));

        if (t->attrset & (1 << NFCT_TIMEOUT_ATTR_L4PROTO))
                mnl_attr_put_u8(nlh, CTA_TIMEOUT_L4PROTO, t->l4num);

        if (t->attrset & (1 << NFCT_TIMEOUT_ATTR_POLICY) && t->polset) {
                nest = mnl_attr_nest_start(nlh, CTA_TIMEOUT_DATA);

                for (i=0; i<timeout_protocol[t->l4num].attr_max; i++) {
                        if (t->polset & (1 << i)) {
                                mnl_attr_put_u32(nlh, i+1,
                                                 htonl(t->timeout[i]));
                        }
                }
                mnl_attr_nest_end(nlh, nest);
        }

}
EXPORT_SYMBOL(nfct_timeout_nlmsg_build_payload);

static int
timeout_nlmsg_parse_attr_cb(const struct nlattr *attr, void *data)
{
        const struct nlattr **tb = data;
        uint16_t type = mnl_attr_get_type(attr);

        if (mnl_attr_type_valid(attr, CTA_TIMEOUT_MAX) < 0)
                return MNL_CB_OK;

        switch(type) {
        case CTA_TIMEOUT_NAME:
                if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0) {
                        perror("mnl_attr_validate");
                        return MNL_CB_ERROR;
                }
                break;
        case CTA_TIMEOUT_L3PROTO:
                if (mnl_attr_validate(attr, MNL_TYPE_U16) < 0) {
                        perror("mnl_attr_validate");
                        return MNL_CB_ERROR;
                }
                break;
        case CTA_TIMEOUT_L4PROTO:
                if (mnl_attr_validate(attr, MNL_TYPE_U8) < 0) {
                        perror("mnl_attr_validate");
                        return MNL_CB_ERROR;
                }
                break;
        case CTA_TIMEOUT_DATA:
                if (mnl_attr_validate(attr, MNL_TYPE_NESTED) < 0) {
                        perror("mnl_attr_validate");
                        return MNL_CB_ERROR;
                }
                break;
        }
        tb[type] = attr;
        return MNL_CB_OK;
}

struct _container_policy_cb {
        unsigned int nlattr_max;
        void *tb;
};

static int
parse_timeout_attr_policy_cb(const struct nlattr *attr, void *data)
{
        struct _container_policy_cb *data_cb = data;
        const struct nlattr **tb = data_cb->tb;
        uint16_t type = mnl_attr_get_type(attr);

        if (mnl_attr_type_valid(attr, data_cb->nlattr_max) < 0)
                return MNL_CB_OK;

        if (type <= data_cb->nlattr_max) {
                if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) {
                        perror("mnl_attr_validate");
                        return MNL_CB_ERROR;
                }
                tb[type] = attr;
        }
        return MNL_CB_OK;
}

static void
timeout_parse_attr_data(struct nfct_timeout *t, const struct nlattr *nest)
{
        unsigned int nlattr_max = timeout_protocol[t->l4num].nlattr_max;
        struct nlattr *tb[nlattr_max];
        struct _container_policy_cb cnt = {
                .nlattr_max = nlattr_max,
                .tb = tb,
        };
        unsigned int i;

        memset(tb, 0, sizeof(struct nlattr *) * nlattr_max);

        mnl_attr_parse_nested(nest, parse_timeout_attr_policy_cb, &cnt);

        for (i=1; i<nlattr_max; i++) {
                if (tb[i]) {
                        nfct_timeout_policy_attr_set_u32(t, i-1,
                                ntohl(mnl_attr_get_u32(tb[i])));
                }
        }
}

int
nfct_timeout_nlmsg_parse_payload(const struct nlmsghdr *nlh,
                                 struct nfct_timeout *t)
{
        struct nlattr *tb[CTA_TIMEOUT_MAX+1] = {};
        struct nfgenmsg *nfg = mnl_nlmsg_get_payload(nlh);

        mnl_attr_parse(nlh, sizeof(*nfg), timeout_nlmsg_parse_attr_cb, tb);
        if (tb[CTA_TIMEOUT_NAME]) {
                nfct_timeout_attr_set(t, NFCT_TIMEOUT_ATTR_NAME,
                        mnl_attr_get_str(tb[CTA_TIMEOUT_NAME]));
        }
        if (tb[CTA_TIMEOUT_L3PROTO]) {
                nfct_timeout_attr_set_u16(t, NFCT_TIMEOUT_ATTR_L3PROTO,
                        ntohs(mnl_attr_get_u16(tb[CTA_TIMEOUT_L3PROTO])));
        }
        if (tb[CTA_TIMEOUT_L4PROTO]) {
                nfct_timeout_attr_set_u8(t, NFCT_TIMEOUT_ATTR_L4PROTO,
                        mnl_attr_get_u8(tb[CTA_TIMEOUT_L4PROTO]));
        }
        if (tb[CTA_TIMEOUT_DATA]) {
                timeout_parse_attr_data(t, tb[CTA_TIMEOUT_DATA]);
        }
        return 0;
}
EXPORT_SYMBOL(nfct_timeout_nlmsg_parse_payload);