/*
 * 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 (c) 2004, 2010, Oracle and/or its affiliates. All rights reserved.
 */

#include <sys/types.h>
#include <sys/systm.h>
#include <sys/stream.h>
#include <sys/cmn_err.h>
#include <sys/strsubr.h>

#include <netinet/in.h>
#include <netinet/ip6.h>

#include <inet/common.h>
#include <inet/ip.h>
#include <inet/mib2.h>
#include <inet/ipclassifier.h>
#include "sctp_impl.h"

void
sctp_return_heartbeat(sctp_t *sctp, sctp_chunk_hdr_t *hbcp, mblk_t *mp)
{
        mblk_t *smp;
        sctp_chunk_hdr_t *cp;
        ipha_t *iniph;
        ip6_t *inip6h;
        int isv4;
        in6_addr_t addr;
        sctp_faddr_t *fp;
        uint16_t len;
        sctp_stack_t    *sctps = sctp->sctp_sctps;

        BUMP_LOCAL(sctp->sctp_ibchunks);

        /* Update the faddr for the src addr */
        isv4 = (IPH_HDR_VERSION(mp->b_rptr) == IPV4_VERSION);
        if (isv4) {
                iniph = (ipha_t *)mp->b_rptr;
                IN6_IPADDR_TO_V4MAPPED(iniph->ipha_src, &addr);
        } else {
                inip6h = (ip6_t *)mp->b_rptr;
                addr = inip6h->ip6_src;
        }
        fp = sctp_lookup_faddr(sctp, &addr);
        /* If the source address is bogus we silently drop the packet */
        if (fp == NULL) {
                dprint(1,
                    ("sctp_return_heartbeat: %p bogus hb from %x:%x:%x:%x\n",
                    (void *)sctp, SCTP_PRINTADDR(addr)));
                SCTP_KSTAT(sctps, sctp_return_hb_failed);
                return;
        }
        dprint(3, ("sctp_return_heartbeat: %p got hb from %x:%x:%x:%x\n",
            (void *)sctp, SCTP_PRINTADDR(addr)));

        /*
         * XXX It's really tempting to reuse the heartbeat mblk. But
         * this complicates processing in sctp_dispatch (i.e. it will
         * screw up sctp_next_chunk since we will set the chunk
         * header's length into network byte-order), and if we ever
         * encounter a heartbeat bundled with other chunks...
         * So we take the slower-but-safe route.
         */
        len = ntohs(hbcp->sch_len);

        /* Create an IP header, returning to the src addr from the heartbt */
        smp = sctp_make_mp(sctp, fp, len);
        if (smp == NULL) {
                SCTP_KSTAT(sctps, sctp_return_hb_failed);
                return;
        }

        cp = (sctp_chunk_hdr_t *)smp->b_wptr;
        cp->sch_id = CHUNK_HEARTBEAT_ACK;
        cp->sch_flags = 0;
        cp->sch_len = htons(len);

        /* Copy the information field from the heartbeat */
        bcopy((void *)(hbcp + 1), (void *)(cp + 1), len - sizeof (*cp));

        smp->b_wptr += len;

        BUMP_LOCAL(sctp->sctp_obchunks);

        sctp_set_iplen(sctp, smp, fp->sf_ixa);
        (void) conn_ip_output(smp, fp->sf_ixa);
        BUMP_LOCAL(sctp->sctp_opkts);
}

/*
 * The data section of the heartbeat contains a time field (lbolt64),
 * a 64 bit secret, followed by the v6 (possible a v4mapped) address this
 * heartbeat was sent to.  No byte-ordering is done, since the heartbeat
 * is not interpreted by the peer.
 */
void
sctp_send_heartbeat(sctp_t *sctp, sctp_faddr_t *fp)
{
        sctp_chunk_hdr_t *cp;
        sctp_parm_hdr_t *hpp;
        int64_t *t;
        int64_t now;
        in6_addr_t *a;
        mblk_t *hbmp;
        size_t hblen;
        sctp_stack_t    *sctps = sctp->sctp_sctps;

        dprint(3, ("sctp_send_heartbeat: to %x:%x:%x:%x from %x:%x:%x:%x\n",
            SCTP_PRINTADDR(fp->sf_faddr), SCTP_PRINTADDR(fp->sf_saddr)));

        hblen = sizeof (*cp) +
            sizeof (*hpp) +
            sizeof (*t) +
            sizeof (fp->sf_hb_secret) +
            sizeof (fp->sf_faddr);
        hbmp = sctp_make_mp(sctp, fp, hblen);
        if (hbmp == NULL) {
                SCTP_KSTAT(sctps, sctp_send_hb_failed);
                return;
        }

        cp = (sctp_chunk_hdr_t *)hbmp->b_wptr;
        cp->sch_id = CHUNK_HEARTBEAT;
        cp->sch_flags = 0;
        cp->sch_len = hblen;
        cp->sch_len = htons(cp->sch_len);

        hpp = (sctp_parm_hdr_t *)(cp + 1);
        hpp->sph_type = htons(PARM_HBINFO);
        hpp->sph_len = hblen - sizeof (*cp);
        hpp->sph_len = htons(hpp->sph_len);

        /*
         * Timestamp
         *
         * Copy the current time to the heartbeat and we can use it to
         * calculate the RTT when we get it back in the heartbeat ACK.
         */
        now = ddi_get_lbolt64();
        t = (int64_t *)(hpp + 1);
        bcopy(&now, t, sizeof (now));

        /*
         * Secret
         *
         * The per peer address secret is used to make sure that the heartbeat
         * ack is really in response to our heartbeat.  This prevents blind
         * spoofing of heartbeat ack to fake the validity of an address.
         */
        t++;
        bcopy(&fp->sf_hb_secret, t, sizeof (uint64_t));

        /*
         * Peer address
         *
         * The peer address is used to associate the heartbeat ack with
         * the correct peer address.  The reason is that the peer is
         * multihomed so that it may not use the same address as source
         * in response to our heartbeat.
         */
        a = (in6_addr_t *)(t + 1);
        bcopy(&fp->sf_faddr, a, sizeof (*a));

        hbmp->b_wptr += hblen;

        /* Update the faddr's info */
        fp->sf_lastactive = now;
        fp->sf_hb_pending = B_TRUE;

        BUMP_LOCAL(sctp->sctp_obchunks);
        SCTPS_BUMP_MIB(sctps, sctpTimHeartBeatProbe);

        sctp_set_iplen(sctp, hbmp, fp->sf_ixa);
        (void) conn_ip_output(hbmp, fp->sf_ixa);
        BUMP_LOCAL(sctp->sctp_opkts);
}

/*
 * Call right after any address change to validate peer addresses.
 */
void
sctp_validate_peer(sctp_t *sctp)
{
        sctp_faddr_t    *fp;
        int             cnt;
        int64_t         now;
        int64_t         earliest_expiry;
        sctp_stack_t    *sctps = sctp->sctp_sctps;

        now = ddi_get_lbolt64();
        earliest_expiry = 0;
        cnt = sctps->sctps_maxburst;

        /*
         * Loop thru the list looking for unconfirmed addresses and
         * send a heartbeat.  But we should only send at most sctp_maxburst
         * heartbeats.
         */
        for (fp = sctp->sctp_faddrs; fp != NULL; fp = fp->sf_next) {
                /* No need to validate unreachable address. */
                if (fp->sf_state == SCTP_FADDRS_UNREACH)
                        continue;
                if (fp->sf_state == SCTP_FADDRS_UNCONFIRMED) {
                        if (cnt-- > 0) {
                                fp->sf_hb_expiry = now + fp->sf_rto;
                                sctp_send_heartbeat(sctp, fp);
                        } else {
                                /*
                                 * If we cannot send now, be more aggressive
                                 * and try again about half of RTO.  Note that
                                 * all the unsent probes are set to expire at
                                 * the same time.
                                 */
                                fp->sf_hb_expiry = now +
                                    (sctp->sctp_rto_initial >> 1);
                        }
                }
                /* Find the earliest heartbeat expiry time for ALL fps. */
                if (fp->sf_hb_interval != 0 && (earliest_expiry == 0 ||
                    fp->sf_hb_expiry < earliest_expiry)) {
                        earliest_expiry = fp->sf_hb_expiry;
                }
        }
        /* We use heartbeat timer for autoclose. */
        if (sctp->sctp_autoclose != 0) {
                int64_t expire;

                expire = sctp->sctp_active + sctp->sctp_autoclose;
                if (earliest_expiry == 0 || expire < earliest_expiry)
                        earliest_expiry = expire;
        }

        /*
         * Set the timer to fire for the earliest heartbeat unless
         * heartbeat is disabled for all addresses.
         */
        if (earliest_expiry != 0) {
                earliest_expiry -= now;
                if (earliest_expiry < 0)
                        earliest_expiry = 1;
                sctp_timer(sctp, sctp->sctp_heartbeat_mp, earliest_expiry);
        }
}

/*
 * Process an incoming heartbeat ack.  When sending a heartbeat, we
 * put the timestamp, a secret and the peer address the heartbeat is
 * sent in the data part of the heartbeat.  We will extract this info
 * and verify that this heartbeat ack is valid.
 */
void
sctp_process_heartbeat(sctp_t *sctp, sctp_chunk_hdr_t *cp)
{
        int64_t *sentp, sent;
        uint64_t secret;
        in6_addr_t addr;
        sctp_faddr_t *fp;
        sctp_parm_hdr_t *hpp;
        int64_t now;

        BUMP_LOCAL(sctp->sctp_ibchunks);

        /* Sanity checks */
        ASSERT(OK_32PTR(cp));
        if (ntohs(cp->sch_len) < (sizeof (*cp) + sizeof (*hpp) +
            sizeof (sent) + sizeof (secret) + sizeof (addr))) {
                /* drop it */
                dprint(2, ("sctp_process_heartbeat: malformed ack %p\n",
                    (void *)sctp));
                return;
        }

        hpp = (sctp_parm_hdr_t *)(cp + 1);
        if (ntohs(hpp->sph_type) != PARM_HBINFO ||
            ntohs(hpp->sph_len) != (ntohs(cp->sch_len) - sizeof (*cp))) {
                dprint(2,
                    ("sctp_process_heartbeat: malformed param in ack %p\n",
                    (void *)sctp));
                return;
        }

        /*
         * Pull out the time sent from the ack.
         * SCTP is 32-bit aligned, so copy 64 bit quantity.  Since we
         * put it in, it should be in our byte order.
         */
        sentp = (int64_t *)(hpp + 1);
        bcopy(sentp, &sent, sizeof (sent));

        /* Grab the secret to make sure that this heartbeat is valid */
        bcopy(++sentp, &secret, sizeof (secret));

        /* Next, verify the address to make sure that it is the right one. */
        bcopy(++sentp, &addr, sizeof (addr));
        fp = sctp_lookup_faddr(sctp, &addr);
        if (fp == NULL) {
                dprint(2, ("sctp_process_heartbeat: invalid faddr (sctp=%p)\n",
                    (void *)sctp));
                return;
        }
        if (secret != fp->sf_hb_secret) {
                dprint(2,
                    ("sctp_process_heartbeat: invalid secret in ack %p\n",
                    (void *)sctp));
                return;
        }

        /* This address is now confirmed and alive. */
        sctp_faddr_alive(sctp, fp);
        now = ddi_get_lbolt64();
        sctp_update_rtt(sctp, fp, now - sent);

        /*
         * Note that the heartbeat timer should still be running, we don't
         * reset it to avoid going through the whole list of peer addresses
         * for each heartbeat ack as we probably are in interrupt context.
         */
        fp->sf_hb_expiry = now + SET_HB_INTVL(fp);
}