Merge commit '80d5689f5d4588adc071138e25e9d0d5252d9b55'

[unleashed.git] / kernel / net / ip / ip6_output.c

/*
 * 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 2010 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 * Copyright 2017 OmniTI Computer Consulting, Inc. All rights reserved.
 */
/* Copyright (c) 1990 Mentat Inc. */

#include <sys/types.h>
#include <sys/stream.h>
#include <sys/strsubr.h>
#include <sys/dlpi.h>
#include <sys/strsun.h>
#include <sys/zone.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>
#include <sys/cmn_err.h>
#include <sys/debug.h>
#include <sys/atomic.h>

#include <sys/systm.h>
#include <sys/param.h>
#include <sys/kmem.h>
#include <sys/sdt.h>
#include <sys/socket.h>
#include <sys/mac.h>
#include <net/if.h>
#include <net/if_arp.h>
#include <net/route.h>
#include <sys/sockio.h>
#include <netinet/in.h>
#include <net/if_dl.h>

#include <inet/common.h>
#include <inet/mi.h>
#include <inet/mib2.h>
#include <inet/nd.h>
#include <inet/arp.h>
#include <inet/snmpcom.h>
#include <inet/kstatcom.h>

#include <netinet/igmp_var.h>
#include <netinet/ip6.h>
#include <netinet/icmp6.h>
#include <netinet/sctp.h>

#include <inet/ip.h>
#include <inet/ip_impl.h>
#include <inet/ip6.h>
#include <inet/ip6_asp.h>
#include <inet/tcp.h>
#include <inet/ip_multi.h>
#include <inet/ip_if.h>
#include <inet/ip_ire.h>
#include <inet/ip_ftable.h>
#include <inet/ip_rts.h>
#include <inet/optcom.h>
#include <inet/ip_ndp.h>
#include <inet/ip_listutils.h>
#include <netinet/igmp.h>
#include <netinet/ip_mroute.h>
#include <inet/ipp_common.h>

#include <net/pfkeyv2.h>
#include <inet/sadb.h>
#include <inet/ipsec_impl.h>
#include <inet/ipdrop.h>
#include <inet/ip_netinfo.h>

#include <sys/pattr.h>
#include <inet/ipclassifier.h>
#include <inet/sctp_ip.h>
#include <inet/sctp/sctp_impl.h>
#include <inet/udp_impl.h>
#include <sys/sunddi.h>

#ifdef  DEBUG
extern boolean_t skip_sctp_cksum;
#endif

int
ip_output_simple_v6(mblk_t *mp, ip_xmit_attr_t *ixa)
{
        ip6_t           *ip6h;
        in6_addr_t      firsthop; /* In IP header */
        in6_addr_t      dst;    /* End of source route, or ip6_dst if none */
        ire_t           *ire;
        in6_addr_t      setsrc;
        int             error;
        ill_t           *ill = NULL;
        dce_t           *dce = NULL;
        nce_t           *nce;
        iaflags_t       ixaflags = ixa->ixa_flags;
        ip_stack_t      *ipst = ixa->ixa_ipst;
        uint8_t         *nexthdrp;
        boolean_t       repeat = B_FALSE;
        uint_t          ifindex;
        int64_t         now;

        ip6h = (ip6_t *)mp->b_rptr;
        ASSERT(IPH_HDR_VERSION(ip6h) == IPV6_VERSION);

        ASSERT(ixa->ixa_nce == NULL);

        ixa->ixa_pktlen = ntohs(ip6h->ip6_plen) + IPV6_HDR_LEN;
        ASSERT(ixa->ixa_pktlen == msgdsize(mp));
        if (!ip_hdr_length_nexthdr_v6(mp, ip6h, &ixa->ixa_ip_hdr_length,
            &nexthdrp)) {
                /* Malformed packet */
                BUMP_MIB(&ipst->ips_ip_mib, ipIfStatsHCOutRequests);
                BUMP_MIB(&ipst->ips_ip_mib, ipIfStatsOutDiscards);
                ip_drop_output("ipIfStatsOutDiscards", mp, NULL);
                freemsg(mp);
                return (EINVAL);
        }
        ixa->ixa_protocol = *nexthdrp;

        /*
         * Assumes that source routed packets have already been massaged by
         * the ULP (ip_massage_options_v6) and as a result ip6_dst is the next
         * hop in the source route. The final destination is used for IPsec
         * policy and DCE lookup.
         */
        firsthop = ip6h->ip6_dst;
        dst = ip_get_dst_v6(ip6h, mp, NULL);

repeat_ire:
        error = 0;
        setsrc = ipv6_all_zeros;
        ire = ip_select_route_v6(&firsthop, ip6h->ip6_src, ixa, NULL, &setsrc,
            &error);
        ASSERT(ire != NULL);    /* IRE_NOROUTE if none found */
        if (error != 0) {
                BUMP_MIB(&ipst->ips_ip_mib, ipIfStatsHCOutRequests);
                BUMP_MIB(&ipst->ips_ip_mib, ipIfStatsOutDiscards);
                ip_drop_output("ipIfStatsOutDiscards", mp, NULL);
                freemsg(mp);
                goto done;
        }

        if (ire->ire_flags & (RTF_BLACKHOLE|RTF_REJECT)) {
                /* ire_ill might be NULL hence need to skip some code */
                if (ixaflags & IXAF_SET_SOURCE)
                        ip6h->ip6_src = ipv6_loopback;
                ixa->ixa_fragsize = IP_MAXPACKET;
                ire->ire_ob_pkt_count++;
                BUMP_MIB(&ipst->ips_ip_mib, ipIfStatsHCOutRequests);
                /* No dce yet; use default one */
                error = (ire->ire_sendfn)(ire, mp, ip6h, ixa,
                    &ipst->ips_dce_default->dce_ident);
                goto done;
        }

        /* Note that ip6_dst is only used for IRE_MULTICAST */
        nce = ire_to_nce(ire, INADDR_ANY, &ip6h->ip6_dst);
        if (nce == NULL) {
                /* Allocation failure? */
                ip_drop_output("ire_to_nce", mp, ill);
                freemsg(mp);
                error = ENOBUFS;
                goto done;
        }
        if (nce->nce_is_condemned) {
                nce_t *nce1;

                nce1 = ire_handle_condemned_nce(nce, ire, NULL, ip6h, B_TRUE);
                nce_refrele(nce);
                if (nce1 == NULL) {
                        if (!repeat) {
                                /* Try finding a better IRE */
                                repeat = B_TRUE;
                                ire_refrele(ire);
                                goto repeat_ire;
                        }
                        /* Tried twice - drop packet */
                        BUMP_MIB(&ipst->ips_ip_mib, ipIfStatsOutDiscards);
                        ip_drop_output("No nce", mp, ill);
                        freemsg(mp);
                        error = ENOBUFS;
                        goto done;
                }
                nce = nce1;
        }

        ixa->ixa_postfragfn = ire->ire_postfragfn;

        ASSERT(ixa->ixa_nce == NULL);
        ixa->ixa_nce = nce;

        /*
         * Check for a dce_t with a path mtu.
         */
        ifindex = 0;
        if (IN6_IS_ADDR_LINKSCOPE(&dst))
                ifindex = nce->nce_common->ncec_ill->ill_phyint->phyint_ifindex;

        dce = dce_lookup_v6(&dst, ifindex, ipst, NULL);
        ASSERT(dce != NULL);

        if (!(ixaflags & IXAF_PMTU_DISCOVERY)) {
                ixa->ixa_fragsize = IPV6_MIN_MTU;
        } else if (dce->dce_flags & DCEF_PMTU) {
                /*
                 * To avoid a periodic timer to increase the path MTU we
                 * look at dce_last_change_time each time we send a packet.
                 */
                now = ddi_get_lbolt64();
                if (TICK_TO_SEC(now) - dce->dce_last_change_time >
                    ipst->ips_ip_pathmtu_interval) {
                        /*
                         * Older than 20 minutes. Drop the path MTU information.
                         */
                        mutex_enter(&dce->dce_lock);
                        dce->dce_flags &= ~DCEF_PMTU;
                        dce->dce_last_change_time = TICK_TO_SEC(now);
                        mutex_exit(&dce->dce_lock);
                        dce_increment_generation(dce);
                        ixa->ixa_fragsize = ip_get_base_mtu(nce->nce_ill, ire);
                } else {
                        uint_t fragsize;

                        fragsize = ip_get_base_mtu(nce->nce_ill, ire);
                        if (fragsize > dce->dce_pmtu)
                                fragsize = dce->dce_pmtu;
                        ixa->ixa_fragsize = fragsize;
                }
        } else {
                ixa->ixa_fragsize = ip_get_base_mtu(nce->nce_ill, ire);
        }

        /*
         * We use use ire_nexthop_ill (and not ncec_ill) to avoid the under ipmp
         * interface for source address selection.
         */
        ill = ire_nexthop_ill(ire);

        if (ixaflags & IXAF_SET_SOURCE) {
                in6_addr_t      src;

                /*
                 * We use the final destination to get
                 * correct selection for source routed packets
                 */

                /* If unreachable we have no ill but need some source */
                if (ill == NULL) {
                        src = ipv6_loopback;
                        error = 0;
                } else {
                        error = ip_select_source_v6(ill, &setsrc, &dst,
                            ixa->ixa_zoneid, ipst, B_FALSE,
                            ixa->ixa_src_preferences, &src, NULL, NULL);
                }
                if (error != 0) {
                        BUMP_MIB(ill->ill_ip_mib, ipIfStatsHCOutRequests);
                        BUMP_MIB(ill->ill_ip_mib, ipIfStatsOutDiscards);
                        ip_drop_output("ipIfStatsOutDiscards - no source",
                            mp, ill);
                        freemsg(mp);
                        goto done;
                }
                ip6h->ip6_src = src;
        } else if (ixaflags & IXAF_VERIFY_SOURCE) {
                /* Check if the IP source is assigned to the host. */
                if (!ip_verify_src(mp, ixa, NULL)) {
                        /* Don't send a packet with a source that isn't ours */
                        BUMP_MIB(&ipst->ips_ip_mib, ipIfStatsHCOutRequests);
                        BUMP_MIB(&ipst->ips_ip_mib, ipIfStatsOutDiscards);
                        ip_drop_output("ipIfStatsOutDiscards - invalid source",
                            mp, ill);
                        freemsg(mp);
                        error = EADDRNOTAVAIL;
                        goto done;
                }
        }

        /*
         * Check against global IPsec policy to set the AH/ESP attributes.
         * IPsec will set IXAF_IPSEC_* and ixa_ipsec_* as appropriate.
         */
        if (!(ixaflags & (IXAF_NO_IPSEC|IXAF_IPSEC_SECURE))) {
                ASSERT(ixa->ixa_ipsec_policy == NULL);
                mp = ip_output_attach_policy(mp, NULL, ip6h, NULL, ixa);
                if (mp == NULL) {
                        /* MIB and ip_drop_packet already done */
                        return (EHOSTUNREACH);  /* IPsec policy failure */
                }
        }

        if (ill != NULL) {
                BUMP_MIB(ill->ill_ip_mib, ipIfStatsHCOutRequests);
        } else {
                BUMP_MIB(&ipst->ips_ip_mib, ipIfStatsHCOutRequests);
        }

        /*
         * We update the statistics on the most specific IRE i.e., the first
         * one we found.
         * We don't have an IRE when we fragment, hence ire_ob_pkt_count
         * can only count the use prior to fragmentation. However the MIB
         * counters on the ill will be incremented in post fragmentation.
         */
        ire->ire_ob_pkt_count++;

        /*
         * Based on ire_type and ire_flags call one of:
         *      ire_send_local_v6 - for IRE_LOCAL and IRE_LOOPBACK
         *      ire_send_noroute_v6 - if RTF_REJECT or RTF_BLACHOLE
         *      ire_send_multicast_v6 - for IRE_MULTICAST
         *      ire_send_wire_v6 - for the rest.
         */
        error = (ire->ire_sendfn)(ire, mp, ip6h, ixa, &dce->dce_ident);
done:
        ire_refrele(ire);
        if (dce != NULL)
                dce_refrele(dce);
        if (ill != NULL)
                ill_refrele(ill);
        if (ixa->ixa_nce != NULL)
                nce_refrele(ixa->ixa_nce);
        ixa->ixa_nce = NULL;
        return (error);
}

/*
 * ire_sendfn() functions.
 * These functions use the following xmit_attr:
 *  - ixa_fragsize - read to determine whether or not to fragment
 *  - IXAF_IPSEC_SECURE - to determine whether or not to invoke IPsec
 *  - ixa_ipsec_*  are used inside IPsec
 *  - IXAF_LOOPBACK_COPY - for multicast
 */


/*
 * ire_sendfn for IRE_LOCAL and IRE_LOOPBACK
 *
 * The checks for restrict_interzone_loopback are done in ire_route_recursive.
 */
/* ARGSUSED4 */
int
ire_send_local_v6(ire_t *ire, mblk_t *mp, void *iph_arg,
    ip_xmit_attr_t *ixa, uint32_t *identp)
{
        ip6_t           *ip6h = (ip6_t *)iph_arg;
        ip_stack_t      *ipst = ixa->ixa_ipst;
        ill_t           *ill = ire->ire_ill;
        ip_recv_attr_t  iras;   /* NOTE: No bzero for performance */
        uint_t          pktlen = ixa->ixa_pktlen;

        /*
         * No fragmentation, no nce, and no application of IPsec.
         *
         *
         * Note different order between IP provider and FW_HOOKS than in
         * send_wire case.
         */

        /*
         * DTrace this as ip:::send.  A packet blocked by FW_HOOKS will fire the
         * send probe, but not the receive probe.
         */
        DTRACE_IP7(send, mblk_t *, mp, conn_t *, NULL, void_ip_t *,
            ip6h, __dtrace_ipsr_ill_t *, ill, ipha_t *, NULL, ip6_t *, ip6h,
            int, 1);

        DTRACE_PROBE4(ip6__loopback__out__start,
            ill_t *, NULL, ill_t *, ill,
            ip6_t *, ip6h, mblk_t *, mp);

        if (HOOKS6_INTERESTED_LOOPBACK_OUT(ipst)) {
                int     error;

                FW_HOOKS(ipst->ips_ip6_loopback_out_event,
                    ipst->ips_ipv6firewall_loopback_out,
                    NULL, ill, ip6h, mp, mp, 0, ipst, error);

                DTRACE_PROBE1(ip6__loopback__out__end, mblk_t *, mp);
                if (mp == NULL)
                        return (error);

                /*
                 * Even if the destination was changed by the filter we use the
                 * forwarding decision that was made based on the address
                 * in ip_output/ip_set_destination.
                 */
                /* Length could be different */
                ip6h = (ip6_t *)mp->b_rptr;
                pktlen = ntohs(ip6h->ip6_plen) + IPV6_HDR_LEN;
        }

        /*
         * If a callback is enabled then we need to know the
         * source and destination zoneids for the packet. We already
         * have those handy.
         */
        if (ipst->ips_ip6_observe.he_interested) {
                zoneid_t szone, dzone;
                zoneid_t stackzoneid;

                stackzoneid = netstackid_to_zoneid(
                    ipst->ips_netstack->netstack_stackid);

                if (stackzoneid == GLOBAL_ZONEID) {
                        /* Shared-IP zone */
                        dzone = ire->ire_zoneid;
                        szone = ixa->ixa_zoneid;
                } else {
                        szone = dzone = stackzoneid;
                }
                ipobs_hook(mp, IPOBS_HOOK_LOCAL, szone, dzone, ill, ipst);
        }

        /* Handle lo0 stats */
        ipst->ips_loopback_packets++;

        /*
         * Update output mib stats. Note that we can't move into the icmp
         * sender (icmp_output etc) since they don't know the ill and the
         * stats are per ill.
         */
        if (ixa->ixa_protocol == IPPROTO_ICMPV6) {
                icmp6_t         *icmp6;

                icmp6 = (icmp6_t *)((uchar_t *)ip6h + ixa->ixa_ip_hdr_length);
                icmp_update_out_mib_v6(ill, icmp6);
        }

        DTRACE_PROBE4(ip6__loopback__in__start,
            ill_t *, ill, ill_t *, NULL,
            ip6_t *, ip6h, mblk_t *, mp);

        if (HOOKS6_INTERESTED_LOOPBACK_IN(ipst)) {
                int     error;

                FW_HOOKS(ipst->ips_ip6_loopback_in_event,
                    ipst->ips_ipv6firewall_loopback_in,
                    ill, NULL, ip6h, mp, mp, 0, ipst, error);

                DTRACE_PROBE1(ip6__loopback__in__end, mblk_t *, mp);
                if (mp == NULL)
                        return (error);

                /*
                 * Even if the destination was changed by the filter we use the
                 * forwarding decision that was made based on the address
                 * in ip_output/ip_set_destination.
                 */
                /* Length could be different */
                ip6h = (ip6_t *)mp->b_rptr;
                pktlen = ntohs(ip6h->ip6_plen) + IPV6_HDR_LEN;
        }

        DTRACE_IP7(receive, mblk_t *, mp, conn_t *, NULL, void_ip_t *,
            ip6h, __dtrace_ipsr_ill_t *, ill, ipha_t *, NULL, ip6_t *, ip6h,
            int, 1);

        /* Map ixa to ira including IPsec policies */
        ipsec_out_to_in(ixa, ill, &iras);
        iras.ira_pktlen = pktlen;

        ire->ire_ib_pkt_count++;
        BUMP_MIB(ill->ill_ip_mib, ipIfStatsHCInReceives);
        UPDATE_MIB(ill->ill_ip_mib, ipIfStatsHCInOctets, pktlen);

        /* Destined to ire_zoneid - use that for fanout */
        iras.ira_zoneid = ire->ire_zoneid;

        ip_fanout_v6(mp, ip6h, &iras);

        /* We moved any IPsec refs from ixa to iras */
        ira_cleanup(&iras, B_FALSE);
        return (0);
}

/*
 * ire_sendfn for IRE_MULTICAST
 *
 * Note that we do path MTU discovery by default for IPv6 multicast. But
 * since unconnected UDP and RAW sockets don't set IXAF_PMTU_DISCOVERY
 * only connected sockets get this by default.
 */
int
ire_send_multicast_v6(ire_t *ire, mblk_t *mp, void *iph_arg,
    ip_xmit_attr_t *ixa, uint32_t *identp)
{
        ip6_t           *ip6h = (ip6_t *)iph_arg;
        ip_stack_t      *ipst = ixa->ixa_ipst;
        ill_t           *ill = ire->ire_ill;
        iaflags_t       ixaflags = ixa->ixa_flags;

        /*
         * Check if anything in ip_input_v6 wants a copy of the transmitted
         * packet (after IPsec and fragmentation)
         *
         * 1. Multicast routers always need a copy unless SO_DONTROUTE is set
         *    RSVP and the rsvp daemon is an example of a
         *    protocol and user level process that
         *    handles it's own routing. Hence, it uses the
         *    SO_DONTROUTE option to accomplish this.
         * 2. If the sender has set IP_MULTICAST_LOOP, then we just
         *    check whether there are any receivers for the group on the ill
         *    (ignoring the zoneid).
         * 3. If IP_MULTICAST_LOOP is not set, then we check if there are
         *    any members in other shared-IP zones.
         *    If such members exist, then we indicate that the sending zone
         *    shouldn't get a loopback copy to preserve the IP_MULTICAST_LOOP
         *    behavior.
         *
         * When we loopback we skip hardware checksum to make sure loopback
         * copy is checksumed.
         *
         * Note that ire_ill is the upper in the case of IPMP.
         */
        ixa->ixa_flags &= ~(IXAF_LOOPBACK_COPY | IXAF_NO_HW_CKSUM);
        if (ipst->ips_ip_g_mrouter && ill->ill_mrouter_cnt > 0 &&
            !(ixaflags & IXAF_DONTROUTE)) {
                ixa->ixa_flags |= IXAF_LOOPBACK_COPY | IXAF_NO_HW_CKSUM;
        } else if (ixaflags & IXAF_MULTICAST_LOOP) {
                /*
                 * If this zone or any other zone has members then loopback
                 * a copy.
                 */
                if (ill_hasmembers_v6(ill, &ip6h->ip6_dst))
                        ixa->ixa_flags |= IXAF_LOOPBACK_COPY | IXAF_NO_HW_CKSUM;
        } else if (ipst->ips_netstack->netstack_numzones > 1) {
                /*
                 * This zone should not have a copy. But there are some other
                 * zones which might have members.
                 */
                if (ill_hasmembers_otherzones_v6(ill, &ip6h->ip6_dst,
                    ixa->ixa_zoneid)) {
                        ixa->ixa_flags |= IXAF_NO_LOOP_ZONEID_SET;
                        ixa->ixa_no_loop_zoneid = ixa->ixa_zoneid;
                        ixa->ixa_flags |= IXAF_LOOPBACK_COPY | IXAF_NO_HW_CKSUM;
                }
        }

        /*
         * Unless IPV6_HOPLIMIT already set a ttl, force the ttl to the
         * IP_MULTICAST_TTL value
         */
        if (!(ixaflags & IXAF_NO_TTL_CHANGE)) {
                ip6h->ip6_hops = ixa->ixa_multicast_ttl;
        }

        return (ire_send_wire_v6(ire, mp, ip6h, ixa, identp));
}

/*
 * ire_sendfn for IREs with RTF_REJECT/RTF_BLACKHOLE, including IRE_NOROUTE
 */
/* ARGSUSED4 */
int
ire_send_noroute_v6(ire_t *ire, mblk_t *mp, void *iph_arg,
    ip_xmit_attr_t *ixa, uint32_t *identp)
{
        ip6_t           *ip6h = (ip6_t *)iph_arg;
        ip_stack_t      *ipst = ixa->ixa_ipst;
        ill_t           *ill;
        ip_recv_attr_t  iras;
        boolean_t       dummy;

        BUMP_MIB(&ipst->ips_ip_mib, ipIfStatsOutNoRoutes);

        if (ire->ire_type & IRE_NOROUTE) {
                /* A lack of a route as opposed to RTF_REJECT|BLACKHOLE */
                ip_rts_change_v6(RTM_MISS, &ip6h->ip6_dst, 0, 0, 0, 0, 0, 0,
                    RTA_DST, ipst);
        }

        if (ire->ire_flags & RTF_BLACKHOLE) {
                ip_drop_output("ipIfStatsOutNoRoutes RTF_BLACKHOLE", mp, NULL);
                freemsg(mp);
                /* No error even for local senders - silent blackhole */
                return (0);
        }
        ip_drop_output("ipIfStatsOutNoRoutes RTF_REJECT", mp, NULL);

        /*
         * We need an ill_t for the ip_recv_attr_t even though this packet
         * was never received and icmp_unreachable doesn't currently use
         * ira_ill.
         */
        ill = ill_lookup_on_name("lo0", B_FALSE,
            !(ixa->ixa_flags & IRAF_IS_IPV4), &dummy, ipst);
        if (ill == NULL) {
                freemsg(mp);
                return (EHOSTUNREACH);
        }

        bzero(&iras, sizeof (iras));
        /* Map ixa to ira including IPsec policies */
        ipsec_out_to_in(ixa, ill, &iras);

        icmp_unreachable_v6(mp, ICMP6_DST_UNREACH_NOROUTE, B_FALSE, &iras);
        /* We moved any IPsec refs from ixa to iras */
        ira_cleanup(&iras, B_FALSE);

        ill_refrele(ill);
        return (EHOSTUNREACH);
}

/*
 * Calculate a checksum ignoring any hardware capabilities
 *
 * Returns B_FALSE if the packet was too short for the checksum. Caller
 * should free and do stats.
 */
static boolean_t
ip_output_sw_cksum_v6(mblk_t *mp, ip6_t *ip6h, ip_xmit_attr_t *ixa)
{
        ip_stack_t      *ipst = ixa->ixa_ipst;
        uint_t          pktlen = ixa->ixa_pktlen;
        uint16_t        *cksump;
        uint32_t        cksum;
        uint8_t         protocol = ixa->ixa_protocol;
        uint16_t        ip_hdr_length = ixa->ixa_ip_hdr_length;

#define iphs    ((uint16_t *)ip6h)

        /* Just in case it contained garbage */
        DB_CKSUMFLAGS(mp) &= ~HCK_FLAGS;

        /*
         * Calculate ULP checksum
         */
        if (protocol == IPPROTO_TCP) {
                cksump = IPH_TCPH_CHECKSUMP(ip6h, ip_hdr_length);
                cksum = IP_TCP_CSUM_COMP;
        } else if (protocol == IPPROTO_UDP) {
                cksump = IPH_UDPH_CHECKSUMP(ip6h, ip_hdr_length);
                cksum = IP_UDP_CSUM_COMP;
        } else if (protocol == IPPROTO_SCTP) {
                sctp_hdr_t      *sctph;

                ASSERT(MBLKL(mp) >= (ip_hdr_length + sizeof (*sctph)));
                sctph = (sctp_hdr_t *)(mp->b_rptr + ip_hdr_length);
                /*
                 * Zero out the checksum field to ensure proper
                 * checksum calculation.
                 */
                sctph->sh_chksum = 0;
#ifdef  DEBUG
                if (!skip_sctp_cksum)
#endif
                        sctph->sh_chksum = sctp_cksum(mp, ip_hdr_length);
                return (B_TRUE);
        } else if (ixa->ixa_flags & IXAF_SET_RAW_CKSUM) {
                /*
                 * icmp has placed length and routing
                 * header adjustment in the checksum field.
                 */
                cksump = (uint16_t *)(((uint8_t *)ip6h) + ip_hdr_length +
                    ixa->ixa_raw_cksum_offset);
                cksum = htons(protocol);
        } else if (protocol == IPPROTO_ICMPV6) {
                cksump = IPH_ICMPV6_CHECKSUMP(ip6h, ip_hdr_length);
                cksum = IP_ICMPV6_CSUM_COMP;    /* Pseudo-header cksum */
        } else {
                return (B_TRUE);
        }

        /* ULP puts the checksum field is in the first mblk */
        ASSERT(((uchar_t *)cksump) + sizeof (uint16_t) <= mp->b_wptr);

        /*
         * We accumulate the pseudo header checksum in cksum.
         * This is pretty hairy code, so watch close.  One
         * thing to keep in mind is that UDP and TCP have
         * stored their respective datagram lengths in their
         * checksum fields.  This lines things up real nice.
         */
        cksum += iphs[4] + iphs[5] + iphs[6] + iphs[7] +
            iphs[8] + iphs[9] + iphs[10] + iphs[11] +
            iphs[12] + iphs[13] + iphs[14] + iphs[15] +
            iphs[16] + iphs[17] + iphs[18] + iphs[19];
        cksum = IP_CSUM(mp, ip_hdr_length, cksum);

        /*
         * For UDP/IPv6 a zero UDP checksum is not allowed.
         * Change to 0xffff
         */
        if (protocol == IPPROTO_UDP && cksum == 0)
                *cksump = ~cksum;
        else
                *cksump = cksum;

        IP6_STAT(ipst, ip6_out_sw_cksum);
        IP6_STAT_UPDATE(ipst, ip6_out_sw_cksum_bytes, pktlen);

        /* No IP header checksum for IPv6 */

        return (B_TRUE);
#undef  iphs
}

/* There are drivers that can't do partial checksum for ICMPv6 */
int nxge_cksum_workaround = 1;

/*
 * Calculate the ULP checksum - try to use hardware.
 * In the case of multicast the IXAF_NO_HW_CKSUM is set in which case we use
 * software.
 *
 * Returns B_FALSE if the packet was too short for the checksum. Caller
 * should free and do stats.
 */
static boolean_t
ip_output_cksum_v6(iaflags_t ixaflags, mblk_t *mp, ip6_t *ip6h,
    ip_xmit_attr_t *ixa, ill_t *ill)
{
        uint_t          pktlen = ixa->ixa_pktlen;
        uint16_t        *cksump;
        uint16_t        hck_flags;
        uint32_t        cksum;
        uint8_t         protocol = ixa->ixa_protocol;
        uint16_t        ip_hdr_length = ixa->ixa_ip_hdr_length;

#define iphs    ((uint16_t *)ip6h)

        if ((ixaflags & IXAF_NO_HW_CKSUM) || !ILL_HCKSUM_CAPABLE(ill) ||
            !dohwcksum) {
                return (ip_output_sw_cksum_v6(mp, ip6h, ixa));
        }

        /*
         * Calculate ULP checksum. Note that we don't use cksump and cksum
         * if the ill has FULL support.
         */
        if (protocol == IPPROTO_TCP) {
                cksump = IPH_TCPH_CHECKSUMP(ip6h, ip_hdr_length);
                cksum = IP_TCP_CSUM_COMP;       /* Pseudo-header cksum */
        } else if (protocol == IPPROTO_UDP) {
                cksump = IPH_UDPH_CHECKSUMP(ip6h, ip_hdr_length);
                cksum = IP_UDP_CSUM_COMP;       /* Pseudo-header cksum */
        } else if (protocol == IPPROTO_SCTP) {
                sctp_hdr_t      *sctph;

                ASSERT(MBLKL(mp) >= (ip_hdr_length + sizeof (*sctph)));
                sctph = (sctp_hdr_t *)(mp->b_rptr + ip_hdr_length);
                /*
                 * Zero out the checksum field to ensure proper
                 * checksum calculation.
                 */
                sctph->sh_chksum = 0;
#ifdef  DEBUG
                if (!skip_sctp_cksum)
#endif
                        sctph->sh_chksum = sctp_cksum(mp, ip_hdr_length);
                goto ip_hdr_cksum;
        } else if (ixa->ixa_flags & IXAF_SET_RAW_CKSUM) {
                /*
                 * icmp has placed length and routing
                 * header adjustment in the checksum field.
                 */
                cksump = (uint16_t *)(((uint8_t *)ip6h) + ip_hdr_length +
                    ixa->ixa_raw_cksum_offset);
                cksum = htons(protocol);
        } else if (protocol == IPPROTO_ICMPV6) {
                cksump = IPH_ICMPV6_CHECKSUMP(ip6h, ip_hdr_length);
                cksum = IP_ICMPV6_CSUM_COMP;    /* Pseudo-header cksum */
        } else {
        ip_hdr_cksum:
                /* No IP header checksum for IPv6 */
                return (B_TRUE);
        }

        /* ULP puts the checksum field is in the first mblk */
        ASSERT(((uchar_t *)cksump) + sizeof (uint16_t) <= mp->b_wptr);

        /*
         * Underlying interface supports hardware checksum offload for
         * the payload; leave the payload checksum for the hardware to
         * calculate.  N.B: We only need to set up checksum info on the
         * first mblk.
         */
        hck_flags = ill->ill_hcksum_capab->ill_hcksum_txflags;

        DB_CKSUMFLAGS(mp) &= ~HCK_FLAGS;
        if (hck_flags & HCKSUM_INET_FULL_V6) {
                /*
                 * Hardware calculates pseudo-header, header and the
                 * payload checksums, so clear the checksum field in
                 * the protocol header.
                 */
                *cksump = 0;
                DB_CKSUMFLAGS(mp) |= HCK_FULLCKSUM;
                return (B_TRUE);
        }
        if (((hck_flags) & HCKSUM_INET_PARTIAL) &&
            (protocol != IPPROTO_ICMPV6 || !nxge_cksum_workaround)) {
                /*
                 * Partial checksum offload has been enabled.  Fill
                 * the checksum field in the protocol header with the
                 * pseudo-header checksum value.
                 *
                 * We accumulate the pseudo header checksum in cksum.
                 * This is pretty hairy code, so watch close.  One
                 * thing to keep in mind is that UDP and TCP have
                 * stored their respective datagram lengths in their
                 * checksum fields.  This lines things up real nice.
                 */
                cksum += iphs[4] + iphs[5] + iphs[6] + iphs[7] +
                    iphs[8] + iphs[9] + iphs[10] + iphs[11] +
                    iphs[12] + iphs[13] + iphs[14] + iphs[15] +
                    iphs[16] + iphs[17] + iphs[18] + iphs[19];
                cksum += *(cksump);
                cksum = (cksum & 0xFFFF) + (cksum >> 16);
                *(cksump) = (cksum & 0xFFFF) + (cksum >> 16);

                /*
                 * Offsets are relative to beginning of IP header.
                 */
                DB_CKSUMSTART(mp) = ip_hdr_length;
                DB_CKSUMSTUFF(mp) = (uint8_t *)cksump - (uint8_t *)ip6h;
                DB_CKSUMEND(mp) = pktlen;
                DB_CKSUMFLAGS(mp) |= HCK_PARTIALCKSUM;
                return (B_TRUE);
        }
        /* Hardware capabilities include neither full nor partial IPv6 */
        return (ip_output_sw_cksum_v6(mp, ip6h, ixa));
#undef  iphs
}

/*
 * ire_sendfn for offlink and onlink destinations.
 * Also called from the multicast send function.
 *
 * Assumes that the caller has a hold on the ire.
 *
 * This function doesn't care if the IRE just became condemned since that
 * can happen at any time.
 */
/* ARGSUSED */
int
ire_send_wire_v6(ire_t *ire, mblk_t *mp, void *iph_arg,
    ip_xmit_attr_t *ixa, uint32_t *identp)
{
        ip_stack_t      *ipst = ixa->ixa_ipst;
        ip6_t           *ip6h = (ip6_t *)iph_arg;
        iaflags_t       ixaflags = ixa->ixa_flags;
        ill_t           *ill;
        uint32_t        pktlen = ixa->ixa_pktlen;

        ASSERT(ixa->ixa_nce != NULL);
        ill = ixa->ixa_nce->nce_ill;

        /*
         * Update output mib stats. Note that we can't move into the icmp
         * sender (icmp_output etc) since they don't know the ill and the
         * stats are per ill.
         *
         * With IPMP we record the stats on the upper ill.
         */
        if (ixa->ixa_protocol == IPPROTO_ICMPV6) {
                icmp6_t         *icmp6;

                icmp6 = (icmp6_t *)((uchar_t *)ip6h + ixa->ixa_ip_hdr_length);
                icmp_update_out_mib_v6(ixa->ixa_nce->nce_common->ncec_ill,
                    icmp6);
        }

        if (ixaflags & IXAF_DONTROUTE)
                ip6h->ip6_hops = 1;

        /*
         * This might set b_band, thus the IPsec and fragmentation
         * code in IP ensures that b_band is updated in the first mblk.
         */
        if (IPP_ENABLED(IPP_LOCAL_OUT, ipst)) {
                /* ip_process translates an IS_UNDER_IPMP */
                mp = ip_process(IPP_LOCAL_OUT, mp, ill, ill);
                if (mp == NULL) {
                        /* ip_drop_packet and MIB done */
                        return (0);     /* Might just be delayed */
                }
        }

        if (pktlen > ixa->ixa_fragsize ||
            (ixaflags & (IXAF_IPSEC_SECURE|IXAF_IPV6_ADD_FRAGHDR))) {
                uint32_t ident;

                if (ixaflags & IXAF_IPSEC_SECURE)
                        pktlen += ipsec_out_extra_length(ixa);

                if (pktlen > IP_MAXPACKET)
                        return (EMSGSIZE);

                if (ixaflags & IXAF_SET_ULP_CKSUM) {
                        /*
                         * Compute ULP checksum using software
                         */
                        if (!ip_output_sw_cksum_v6(mp, ip6h, ixa)) {
                                BUMP_MIB(ill->ill_ip_mib, ipIfStatsOutDiscards);
                                ip_drop_output("ipIfStatsOutDiscards", mp, ill);
                                freemsg(mp);
                                return (EINVAL);
                        }
                        /* Avoid checksum again below if we only add fraghdr */
                        ixaflags &= ~IXAF_SET_ULP_CKSUM;
                }

                /*
                 * If we need a fragment header, pick the ident and insert
                 * the header before IPsec to we have a place to store
                 * the ident value.
                 */
                if ((ixaflags & IXAF_IPV6_ADD_FRAGHDR) ||
                    pktlen > ixa->ixa_fragsize) {
                        /*
                         * If this packet would generate a icmp_frag_needed
                         * message, we need to handle it before we do the IPsec
                         * processing. Otherwise, we need to strip the IPsec
                         * headers before we send up the message to the ULPs
                         * which becomes messy and difficult.
                         */
                        if ((pktlen > ixa->ixa_fragsize) &&
                            (ixaflags & IXAF_DONTFRAG)) {
                                /* Generate ICMP and return error */
                                ip_recv_attr_t  iras;

                                DTRACE_PROBE4(ip6__fragsize__fail,
                                    uint_t, pktlen, uint_t, ixa->ixa_fragsize,
                                    uint_t, ixa->ixa_pktlen,
                                    uint_t, ixa->ixa_pmtu);

                                bzero(&iras, sizeof (iras));
                                /* Map ixa to ira including IPsec policies */
                                ipsec_out_to_in(ixa, ill, &iras);

                                ip_drop_output("ICMP6_PKT_TOO_BIG", mp, ill);
                                icmp_pkt2big_v6(mp, ixa->ixa_fragsize, B_TRUE,
                                    &iras);
                                /* We moved any IPsec refs from ixa to iras */
                                ira_cleanup(&iras, B_FALSE);
                                return (EMSGSIZE);
                        }
                        DTRACE_PROBE4(ip6__fragsize__ok, uint_t, pktlen,
                            uint_t, ixa->ixa_fragsize, uint_t, ixa->ixa_pktlen,
                            uint_t, ixa->ixa_pmtu);
                        /*
                         * Assign an ident value for this packet. There could
                         * be other threads targeting the same destination, so
                         * we have to arrange for a atomic increment.
                         * Normally ixa_extra_ident is 0, but in the case of
                         * LSO it will be the number of TCP segments  that the
                         * driver/hardware will extraly construct.
                         */
                        ident = atomic_add_32_nv(identp, ixa->ixa_extra_ident +
                            1);
                        ixa->ixa_ident = ident; /* In case we do IPsec */
                }
                if (ixaflags & IXAF_IPSEC_SECURE) {
                        /*
                         * Pass in sufficient information so that
                         * IPsec can determine whether to fragment, and
                         * which function to call after fragmentation.
                         */
                        return (ipsec_out_process(mp, ixa));
                }

                mp = ip_fraghdr_add_v6(mp, ident, ixa);
                if (mp == NULL) {
                        /* MIB and ip_drop_output already done */
                        return (ENOMEM);
                }
                ASSERT(pktlen == ixa->ixa_pktlen);
                pktlen += sizeof (ip6_frag_t);

                if (pktlen > ixa->ixa_fragsize) {
                        return (ip_fragment_v6(mp, ixa->ixa_nce, ixaflags,
                            pktlen, ixa->ixa_fragsize,
                            ixa->ixa_xmit_hint, ixa->ixa_zoneid,
                            ixa->ixa_no_loop_zoneid, ixa->ixa_postfragfn,
                            &ixa->ixa_cookie));
                }
        }
        if (ixaflags & IXAF_SET_ULP_CKSUM) {
                /* Compute ULP checksum and IP header checksum */
                /* An IS_UNDER_IPMP ill is ok here */
                if (!ip_output_cksum_v6(ixaflags, mp, ip6h, ixa, ill)) {
                        BUMP_MIB(ill->ill_ip_mib, ipIfStatsOutDiscards);
                        ip_drop_output("ipIfStatsOutDiscards", mp, ill);
                        freemsg(mp);
                        return (EINVAL);
                }
        }
        return ((ixa->ixa_postfragfn)(mp, ixa->ixa_nce, ixaflags,
            pktlen, ixa->ixa_xmit_hint, ixa->ixa_zoneid,
            ixa->ixa_no_loop_zoneid, &ixa->ixa_cookie));
}