/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * DL_IPV4 MAC Type plugin for the Nemo mac module
 */

#include <sys/types.h>
#include <sys/modctl.h>
#include <sys/dlpi.h>
#include <sys/mac.h>
#include <sys/mac_ipv4.h>
#include <sys/byteorder.h>
#include <sys/strsun.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <inet/common.h>
#include <inet/ip.h>
#include <inet/iptun.h>

static struct modlmisc mac_ipv4_modlmisc = {
        &mod_miscops,
        "IPv4 tunneling MAC plugin"
};

static struct modlinkage mac_ipv4_modlinkage = {
        MODREV_1,
        &mac_ipv4_modlmisc,
        NULL
};

static mactype_ops_t mac_ipv4_type_ops;

int
_init(void)
{
        mactype_register_t *mtrp;
        int     err;

        if ((mtrp = mactype_alloc(MACTYPE_VERSION)) == NULL)
                return (ENOTSUP);
        mtrp->mtr_ident = MAC_PLUGIN_IDENT_IPV4;
        mtrp->mtr_ops = &mac_ipv4_type_ops;
        mtrp->mtr_mactype = DL_IPV4;
        mtrp->mtr_nativetype = DL_IPV4;
        mtrp->mtr_addrlen = sizeof (ipaddr_t);
        if ((err = mactype_register(mtrp)) == 0) {
                if ((err = mod_install(&mac_ipv4_modlinkage)) != 0)
                        (void) mactype_unregister(MAC_PLUGIN_IDENT_IPV4);
        }
        mactype_free(mtrp);
        return (err);
}

int
_fini(void)
{
        int     err;
        if ((err = mactype_unregister(MAC_PLUGIN_IDENT_IPV4)) != 0)
                return (err);
        return (mod_remove(&mac_ipv4_modlinkage));
}

int
_info(struct modinfo *modinfop)
{
        return (mod_info(&mac_ipv4_modlinkage, modinfop));
}

/*
 * MAC Type plugin operations
 */

/* ARGSUSED */
int
mac_ipv4_unicst_verify(const void *addr, void *pdata)
{
        const ipaddr_t *ipaddr = addr;
        return ((CLASSD(*ipaddr) || (*ipaddr == INADDR_BROADCAST)) ?
            EINVAL : 0);
}

/* ARGSUSED */
int
mac_ipv4_multicst_verify(const void *addr, void *pdata)
{
        /*
         * IPv4 configured tunnels do not have the concept of link-layer
         * multicast.
         */
        return (ENOTSUP);
}

/*
 * Check the legality of an IPv4 tunnel SAP value.  The only two acceptable
 * values are IPPROTO_ENCAP (IPv4 in IPv4) and IPPROTO_IPV6 (IPv6 in IPv4).
 */
/* ARGSUSED */
boolean_t
mac_ipv4_sap_verify(uint32_t sap, uint32_t *bind_sap, void *pdata)
{
        if (sap == IPPROTO_ENCAP || sap == IPPROTO_IPV6 || sap == 0) {
                if (bind_sap != NULL)
                        *bind_sap = sap;
                return (B_TRUE);
        }
        return (B_FALSE);
}

/*
 * Build an IPv4 link-layer header for tunneling.  If provided, the
 * template header provided by the driver supplies the header length, type
 * of service, don't fragment flag, ttl, and potential options (depending
 * on the header length).
 */
/* ARGSUSED */
mblk_t *
mac_ipv4_header(const void *saddr, const void *daddr, uint32_t sap, void *pdata,
    mblk_t *payload, size_t extra_len)
{
        struct ip       *iphp;
        struct ip       *tmpl_iphp = pdata;
        mblk_t          *mp;
        size_t          hdr_len = sizeof (struct ip);

        if (!mac_ipv4_sap_verify(sap, NULL, NULL))
                return (NULL);

        if (tmpl_iphp != NULL)
                hdr_len = tmpl_iphp->ip_hl * sizeof (uint32_t);

        if ((mp = allocb(hdr_len + extra_len, BPRI_HI)) == NULL)
                return (NULL);

        iphp = (struct ip *)mp->b_rptr;

        bzero(iphp, hdr_len + extra_len);
        if (tmpl_iphp != NULL) {
                bcopy(tmpl_iphp, iphp, hdr_len);
        } else {
                iphp->ip_hl = IP_SIMPLE_HDR_LENGTH_IN_WORDS;
                iphp->ip_off = htons(IP_DF);
                iphp->ip_ttl = IPTUN_DEFAULT_HOPLIMIT;
        }

        iphp->ip_v = IPVERSION;
        iphp->ip_len = 0;
        iphp->ip_p = (uint8_t)sap;
        bcopy(saddr, &(iphp->ip_src), sizeof (struct in_addr));
        bcopy(daddr, &(iphp->ip_dst), sizeof (struct in_addr));

        mp->b_wptr += hdr_len;
        return (mp);
}

/* ARGSUSED */
int
mac_ipv4_header_info(mblk_t *mp, void *pdata, mac_header_info_t *hdr_info)
{
        struct ip       *iphp;

        if (MBLKL(mp) < sizeof (struct ip))
                return (EINVAL);

        iphp = (struct ip *)mp->b_rptr;

        /*
         * IPv4 tunnels don't have a concept of link-layer multicast since
         * they have fixed unicast endpoints.
         */
        if (mac_ipv4_unicst_verify(&iphp->ip_dst, NULL) != 0)
                return (EINVAL);

        hdr_info->mhi_hdrsize = iphp->ip_hl * sizeof (uint32_t);
        hdr_info->mhi_pktsize = 0;
        hdr_info->mhi_daddr = (const uint8_t *)&(iphp->ip_dst);
        hdr_info->mhi_saddr = (const uint8_t *)&(iphp->ip_src);
        hdr_info->mhi_origsap = hdr_info->mhi_bindsap = iphp->ip_p;
        hdr_info->mhi_dsttype = MAC_ADDRTYPE_UNICAST;
        return (0);
}

/*
 * Plugin data is either NULL or a pointer to an IPv4 header.
 */
boolean_t
mac_ipv4_pdata_verify(void *pdata, size_t pdata_size)
{
        const struct ip *iphp = pdata;

        if (pdata == NULL)
                return (pdata_size == 0);
        if (pdata_size < sizeof (struct ip))
                return (B_FALSE);
        /* Make sure that the header length field matches pdata_size */
        return (pdata_size == iphp->ip_hl * sizeof (uint32_t));
}

static mactype_ops_t    mac_ipv4_type_ops = {
        MTOPS_PDATA_VERIFY,
        mac_ipv4_unicst_verify,
        mac_ipv4_multicst_verify,
        mac_ipv4_sap_verify,
        mac_ipv4_header,
        mac_ipv4_header_info,
        mac_ipv4_pdata_verify,
        NULL,
        NULL,
        NULL
};