doc: Add `show ipv6 rpf X:X::X:X` command to docs

[mirror_frr.git] / pimd / pim_register.c

/*
 * PIM for Quagga
 * Copyright (C) 2015 Cumulus Networks, Inc.
 * Donald Sharp
 *
 * 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 program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; see the file COPYING; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <zebra.h>

#include "log.h"
#include "if.h"
#include "thread.h"
#include "prefix.h"
#include "vty.h"
#include "plist.h"

#include "pimd.h"
#include "pim_mroute.h"
#include "pim_iface.h"
#include "pim_msg.h"
#include "pim_pim.h"
#include "pim_str.h"
#include "pim_rp.h"
#include "pim_register.h"
#include "pim_upstream.h"
#include "pim_rpf.h"
#include "pim_oil.h"
#include "pim_zebra.h"
#include "pim_join.h"
#include "pim_util.h"
#include "pim_ssm.h"
#include "pim_vxlan.h"
#include "pim_addr.h"

struct thread *send_test_packet_timer = NULL;

void pim_register_join(struct pim_upstream *up)
{
        struct pim_instance *pim = up->channel_oil->pim;

        if (pim_is_grp_ssm(pim, up->sg.grp)) {
                if (PIM_DEBUG_PIM_EVENTS)
                        zlog_debug("%s register setup skipped as group is SSM",
                                   up->sg_str);
                return;
        }

        pim_channel_add_oif(up->channel_oil, pim->regiface,
                            PIM_OIF_FLAG_PROTO_PIM, __func__);
        up->reg_state = PIM_REG_JOIN;
        pim_vxlan_update_sg_reg_state(pim, up, true);
}

void pim_register_stop_send(struct interface *ifp, pim_sgaddr *sg, pim_addr src,
                            pim_addr originator)
{
        struct pim_interface *pinfo;
        unsigned char buffer[10000];
        unsigned int b1length = 0;
        unsigned int length;
        uint8_t *b1;

        if (PIM_DEBUG_PIM_REG) {
                zlog_debug("Sending Register stop for %pSG to %pPA on %s", sg,
                           &originator, ifp->name);
        }

        memset(buffer, 0, 10000);
        b1 = (uint8_t *)buffer + PIM_MSG_REGISTER_STOP_LEN;

        length = pim_encode_addr_group(b1, AFI_IP, 0, 0, sg->grp);
        b1length += length;
        b1 += length;

        length = pim_encode_addr_ucast(b1, sg->src);
        b1length += length;

        pim_msg_build_header(src, originator, buffer,
                             b1length + PIM_MSG_REGISTER_STOP_LEN,
                             PIM_MSG_TYPE_REG_STOP, false);

        pinfo = (struct pim_interface *)ifp->info;
        if (!pinfo) {
                if (PIM_DEBUG_PIM_TRACE)
                        zlog_debug("%s: No pinfo!", __func__);
                return;
        }
        if (pim_msg_send(pinfo->pim_sock_fd, src, originator, buffer,
                         b1length + PIM_MSG_REGISTER_STOP_LEN, ifp)) {
                if (PIM_DEBUG_PIM_TRACE) {
                        zlog_debug(
                                "%s: could not send PIM register stop message on interface %s",
                                __func__, ifp->name);
                }
        }

        if (!pinfo->pim_passive_enable)
                ++pinfo->pim_ifstat_reg_stop_send;
}

static void pim_reg_stop_upstream(struct pim_instance *pim,
                                  struct pim_upstream *up)
{
        switch (up->reg_state) {
        case PIM_REG_NOINFO:
        case PIM_REG_PRUNE:
                return;
        case PIM_REG_JOIN:
                up->reg_state = PIM_REG_PRUNE;
                pim_channel_del_oif(up->channel_oil, pim->regiface,
                                    PIM_OIF_FLAG_PROTO_PIM, __func__);
                pim_upstream_start_register_stop_timer(up, 0);
                pim_vxlan_update_sg_reg_state(pim, up, false);
                break;
        case PIM_REG_JOIN_PENDING:
                up->reg_state = PIM_REG_PRUNE;
                pim_upstream_start_register_stop_timer(up, 0);
                return;
        }
}

int pim_register_stop_recv(struct interface *ifp, uint8_t *buf, int buf_size)
{
        struct pim_interface *pim_ifp = ifp->info;
        struct pim_instance *pim = pim_ifp->pim;
        struct pim_upstream *up = NULL;
        struct pim_rpf *rp;
        pim_sgaddr sg;
        struct listnode *up_node;
        struct pim_upstream *child;
        bool wrong_af = false;
        bool handling_star = false;
        int l;

        if (pim_ifp->pim_passive_enable) {
                if (PIM_DEBUG_PIM_PACKETS)
                        zlog_debug(
                                "skip receiving PIM message on passive interface %s",
                                ifp->name);
                return 0;
        }

        ++pim_ifp->pim_ifstat_reg_stop_recv;

        memset(&sg, 0, sizeof(sg));
        l = pim_parse_addr_group(&sg, buf, buf_size);
        buf += l;
        buf_size -= l;
        pim_parse_addr_ucast(&sg.src, buf, buf_size, &wrong_af);

        if (wrong_af) {
                zlog_err("invalid AF in Register-Stop on %s", ifp->name);
                return -1;
        }


        if (PIM_DEBUG_PIM_REG)
                zlog_debug("Received Register stop for %pSG", &sg);

        rp = RP(pim_ifp->pim, sg.grp);
        if (rp) {
                /* As per RFC 7761, Section 4.9.4:
                 * A special wildcard value consisting of an address field of
                 * all zeros can be used to indicate any source.
                 */
                if ((pim_addr_cmp(sg.src, rp->rpf_addr) == 0) ||
                    pim_addr_is_any(sg.src)) {
                        handling_star = true;
                        sg.src = PIMADDR_ANY;
                }
        }

        /*
         * RFC 7761 Sec 4.4.1
         * Handling Register-Stop(*,G) Messages at the DR:
         *   A Register-Stop(*,G) should be treated as a
         *   Register-Stop(S,G) for all (S,G) Register state
         *   machines that are not in the NoInfo state.
         */
        up = pim_upstream_find(pim, &sg);
        if (up) {
                /*
                 * If the upstream find actually found a particular
                 * S,G then we *know* that the following for loop
                 * is not going to execute and this is ok
                 */
                for (ALL_LIST_ELEMENTS_RO(up->sources, up_node, child)) {
                        if (PIM_DEBUG_PIM_REG)
                                zlog_debug("Executing Reg stop for %s",
                                           child->sg_str);

                        pim_reg_stop_upstream(pim, child);
                }

                if (PIM_DEBUG_PIM_REG)
                        zlog_debug("Executing Reg stop for %s", up->sg_str);
                pim_reg_stop_upstream(pim, up);
        } else {
                if (!handling_star)
                        return 0;
                /*
                 * Unfortunately pim was unable to find a *,G
                 * but pim may still actually have individual
                 * S,G's that need to be processed.  In that
                 * case pim must do the expensive walk to find
                 * and stop
                 */
                frr_each (rb_pim_upstream, &pim->upstream_head, up) {
                        if (pim_addr_cmp(up->sg.grp, sg.grp) == 0) {
                                if (PIM_DEBUG_PIM_REG)
                                        zlog_debug("Executing Reg stop for %s",
                                                   up->sg_str);
                                pim_reg_stop_upstream(pim, up);
                        }
                }
        }

        return 0;
}

#if PIM_IPV == 6
struct in6_addr pim_register_get_unicast_v6_addr(struct pim_interface *p_ifp)
{
        struct listnode *node;
        struct listnode *nextnode;
        struct pim_secondary_addr *sec_addr;
        struct pim_interface *pim_ifp;
        struct interface *ifp;
        struct pim_instance *pim = p_ifp->pim;

        /* Trying to get the unicast address from the RPF interface first */
        for (ALL_LIST_ELEMENTS(p_ifp->sec_addr_list, node, nextnode,
                               sec_addr)) {
                if (!is_ipv6_global_unicast(&sec_addr->addr.u.prefix6))
                        continue;

                return sec_addr->addr.u.prefix6;
        }

        /* Loop through all the pim interface and try to return a global
         * unicast ipv6 address
         */
        FOR_ALL_INTERFACES (pim->vrf, ifp) {
                pim_ifp = ifp->info;

                if (!pim_ifp)
                        continue;

                for (ALL_LIST_ELEMENTS(pim_ifp->sec_addr_list, node, nextnode,
                                       sec_addr)) {
                        if (!is_ipv6_global_unicast(&sec_addr->addr.u.prefix6))
                                continue;

                        return sec_addr->addr.u.prefix6;
                }
        }

        zlog_warn("No global address found for use to send register message");
        return PIMADDR_ANY;
}
#endif

void pim_register_send(const uint8_t *buf, int buf_size, pim_addr src,
                       struct pim_rpf *rpg, int null_register,
                       struct pim_upstream *up)
{
        unsigned char buffer[10000];
        unsigned char *b1;
        struct pim_interface *pinfo;
        struct interface *ifp;

        if (PIM_DEBUG_PIM_REG) {
                zlog_debug("Sending %s %sRegister Packet to %pPA", up->sg_str,
                           null_register ? "NULL " : "", &rpg->rpf_addr);
        }

        ifp = rpg->source_nexthop.interface;
        if (!ifp) {
                if (PIM_DEBUG_PIM_REG)
                        zlog_debug("%s: No interface to transmit register on",
                                   __func__);
                return;
        }
        pinfo = (struct pim_interface *)ifp->info;
        if (!pinfo) {
                if (PIM_DEBUG_PIM_REG)
                        zlog_debug(
                                "%s: Interface: %s not configured for pim to transmit on!",
                                __func__, ifp->name);
                return;
        }

        if (PIM_DEBUG_PIM_REG) {
                zlog_debug("%s: Sending %s %sRegister Packet to %pPA on %s",
                           __func__, up->sg_str, null_register ? "NULL " : "",
                           &rpg->rpf_addr, ifp->name);
        }

        memset(buffer, 0, 10000);
        b1 = buffer + PIM_MSG_HEADER_LEN;
        *b1 |= null_register << 6;
        b1 = buffer + PIM_MSG_REGISTER_LEN;

        memcpy(b1, (const unsigned char *)buf, buf_size);

#if PIM_IPV == 6
        /* While sending Register message to RP, we cannot use link-local
         * address therefore using unicast ipv6 address here, choosing it
         * from the RPF Interface
         */
        src = pim_register_get_unicast_v6_addr(pinfo);
#endif
        pim_msg_build_header(src, rpg->rpf_addr, buffer,
                             buf_size + PIM_MSG_REGISTER_LEN,
                             PIM_MSG_TYPE_REGISTER, false);

        if (!pinfo->pim_passive_enable)
                ++pinfo->pim_ifstat_reg_send;

        if (pim_msg_send(pinfo->pim->reg_sock, src, rpg->rpf_addr, buffer,
                         buf_size + PIM_MSG_REGISTER_LEN, ifp)) {
                if (PIM_DEBUG_PIM_TRACE) {
                        zlog_debug(
                                "%s: could not send PIM register message on interface %s",
                                __func__, ifp->name);
                }
                return;
        }
}

#if PIM_IPV == 4
void pim_null_register_send(struct pim_upstream *up)
{
        struct ip ip_hdr;
        struct pim_interface *pim_ifp;
        struct pim_rpf *rpg;
        pim_addr src;

        pim_ifp = up->rpf.source_nexthop.interface->info;
        if (!pim_ifp) {
                if (PIM_DEBUG_PIM_TRACE)
                        zlog_debug(
                                "%s: Cannot send null-register for %s no valid iif",
                                __func__, up->sg_str);
                return;
        }

        rpg = RP(pim_ifp->pim, up->sg.grp);
        if (!rpg) {
                if (PIM_DEBUG_PIM_TRACE)
                        zlog_debug(
                                "%s: Cannot send null-register for %s no RPF to the RP",
                                __func__, up->sg_str);
                return;
        }

        memset(&ip_hdr, 0, sizeof(ip_hdr));
        ip_hdr.ip_p = PIM_IP_PROTO_PIM;
        ip_hdr.ip_hl = 5;
        ip_hdr.ip_v = 4;
        ip_hdr.ip_src = up->sg.src;
        ip_hdr.ip_dst = up->sg.grp;
        ip_hdr.ip_len = htons(20);

        /* checksum is broken */
        src = pim_ifp->primary_address;
        if (PIM_UPSTREAM_FLAG_TEST_SRC_VXLAN_ORIG(up->flags)) {
                if (!pim_vxlan_get_register_src(pim_ifp->pim, up, &src)) {
                        if (PIM_DEBUG_PIM_TRACE)
                                zlog_debug(
                                        "%s: Cannot send null-register for %s vxlan-aa PIP unavailable",
                                        __func__, up->sg_str);
                        return;
                }
        }
        pim_register_send((uint8_t *)&ip_hdr, sizeof(struct ip), src, rpg, 1,
                          up);
}
#else
void pim_null_register_send(struct pim_upstream *up)
{
        struct ip6_hdr ip6_hdr;
        struct pim_msg_header pim_msg_header;
        struct pim_interface *pim_ifp;
        struct pim_rpf *rpg;
        pim_addr src;
        unsigned char buffer[sizeof(ip6_hdr) + sizeof(pim_msg_header)];
        struct ipv6_ph ph;

        pim_ifp = up->rpf.source_nexthop.interface->info;
        if (!pim_ifp) {
                if (PIM_DEBUG_PIM_TRACE)
                        zlog_debug(
                                "Cannot send null-register for %s no valid iif",
                                up->sg_str);
                return;
        }

        rpg = RP(pim_ifp->pim, up->sg.grp);
        if (!rpg) {
                if (PIM_DEBUG_PIM_TRACE)
                        zlog_debug(
                                "Cannot send null-register for %s no RPF to the RP",
                                up->sg_str);
                return;
        }

        memset(&ip6_hdr, 0, sizeof(ip6_hdr));
        ip6_hdr.ip6_nxt = PIM_IP_PROTO_PIM;
        ip6_hdr.ip6_plen = PIM_MSG_HEADER_LEN;
        ip6_hdr.ip6_vfc = 6 << 4;
        ip6_hdr.ip6_hlim = MAXTTL;
        ip6_hdr.ip6_src = up->sg.src;
        ip6_hdr.ip6_dst = up->sg.grp;

        memset(buffer, 0, (sizeof(ip6_hdr) + sizeof(pim_msg_header)));
        memcpy(buffer, &ip6_hdr, sizeof(ip6_hdr));

        pim_msg_header.ver = 0;
        pim_msg_header.type = 0;
        pim_msg_header.reserved = 0;

        pim_msg_header.checksum = 0;

        ph.src = up->sg.src;
        ph.dst = up->sg.grp;
        ph.ulpl = htonl(PIM_MSG_HEADER_LEN);
        ph.next_hdr = IPPROTO_PIM;
        pim_msg_header.checksum =
                in_cksum_with_ph6(&ph, &pim_msg_header, PIM_MSG_HEADER_LEN);

        memcpy(buffer + sizeof(ip6_hdr), &pim_msg_header, PIM_MSG_HEADER_LEN);


        src = pim_ifp->primary_address;
        pim_register_send((uint8_t *)buffer,
                          sizeof(ip6_hdr) + PIM_MSG_HEADER_LEN, src, rpg, 1,
                          up);
}
#endif

/*
 * 4.4.2 Receiving Register Messages at the RP
 *
 *   When an RP receives a Register message, the course of action is
 *  decided according to the following pseudocode:
 *
 *  packet_arrives_on_rp_tunnel( pkt ) {
 *      if( outer.dst is not one of my addresses ) {
 *          drop the packet silently.
 *          # Note: this may be a spoofing attempt
 *      }
 *      if( I_am_RP(G) AND outer.dst == RP(G) ) {
 *            sentRegisterStop = false;
 *            if ( register.borderbit == true ) {
 *                 if ( PMBR(S,G) == unknown ) {
 *                      PMBR(S,G) = outer.src
 *                 } else if ( outer.src != PMBR(S,G) ) {
 *                      send Register-Stop(S,G) to outer.src
 *                      drop the packet silently.
 *                 }
 *            }
 *            if ( SPTbit(S,G) OR
 *             ( SwitchToSptDesired(S,G) AND
 *               ( inherited_olist(S,G) == NULL ))) {
 *              send Register-Stop(S,G) to outer.src
 *              sentRegisterStop = true;
 *            }
 *            if ( SPTbit(S,G) OR SwitchToSptDesired(S,G) ) {
 *                 if ( sentRegisterStop == true ) {
 *                      set KeepaliveTimer(S,G) to RP_Keepalive_Period;
 *                 } else {
 *                      set KeepaliveTimer(S,G) to Keepalive_Period;
 *                 }
 *            }
 *            if( !SPTbit(S,G) AND ! pkt.NullRegisterBit ) {
 *                 decapsulate and forward the inner packet to
 *                 inherited_olist(S,G,rpt) # Note (+)
 *            }
 *      } else {
 *          send Register-Stop(S,G) to outer.src
 *          # Note (*)
 *      }
 *  }
 */
int pim_register_recv(struct interface *ifp, pim_addr dest_addr,
                      pim_addr src_addr, uint8_t *tlv_buf, int tlv_buf_size)
{
        int sentRegisterStop = 0;
        const void *ip_hdr;
        pim_sgaddr sg;
        uint32_t *bits;
        int i_am_rp = 0;
        struct pim_interface *pim_ifp = ifp->info;
        struct pim_instance *pim = pim_ifp->pim;
        pim_addr rp_addr;

        if (pim_ifp->pim_passive_enable) {
                if (PIM_DEBUG_PIM_PACKETS)
                        zlog_debug(
                                "skip receiving PIM message on passive interface %s",
                                ifp->name);
                return 0;
        }

#define PIM_MSG_REGISTER_BIT_RESERVED_LEN 4
        ip_hdr = (tlv_buf + PIM_MSG_REGISTER_BIT_RESERVED_LEN);

        if (!if_address_is_local(&dest_addr, PIM_AF, pim->vrf->vrf_id)) {
                if (PIM_DEBUG_PIM_REG)
                        zlog_debug(
                                "%s: Received Register message for destination address: %pPA that I do not own",
                                __func__, &dest_addr);
                return 0;
        }

        ++pim_ifp->pim_ifstat_reg_recv;

        /*
         * Please note this is not drawn to get the correct bit/data size
         *
         * The entirety of the REGISTER packet looks like this:
         * -------------------------------------------------------------
         * | Ver  | Type | Reserved     |       Checksum               |
         * |-----------------------------------------------------------|
         * |B|N|     Reserved 2                                        |
         * |-----------------------------------------------------------|
         * | Encap  |                IP HDR                            |
         * | Mcast  |                                                  |
         * | Packet |--------------------------------------------------|
         * |        |               Mcast Data                         |
         * |        |                                                  |
         * ...
         *
         * tlv_buf when received from the caller points at the B bit
         * We need to know the inner source and dest
         */
        bits = (uint32_t *)tlv_buf;

        /*
         * tlv_buf points to the start of the |B|N|... Reserved
         * Line above.  So we need to add 4 bytes to get to the
         * start of the actual Encapsulated data.
         */
        memset(&sg, 0, sizeof(sg));
        sg = pim_sgaddr_from_iphdr(ip_hdr);

#if PIM_IPV == 6
        /*
         * According to RFC section 4.9.3, If Dummy PIM Header is included
         * in NULL Register as a payload there would be two PIM headers.
         * The inner PIM Header's checksum field should also be validated
         * in addition to the outer PIM Header's checksum. Validation of
         * inner PIM header checksum is done here.
         */
        if ((*bits & PIM_REGISTER_NR_BIT) &&
            ((tlv_buf_size - PIM_MSG_REGISTER_BIT_RESERVED_LEN) >
             (int)sizeof(struct ip6_hdr))) {
                uint16_t computed_checksum;
                uint16_t received_checksum;
                struct ipv6_ph ph;
                struct pim_msg_header *header;

                header = (struct pim_msg_header
                                  *)(tlv_buf +
                                     PIM_MSG_REGISTER_BIT_RESERVED_LEN +
                                     sizeof(struct ip6_hdr));
                ph.src = sg.src;
                ph.dst = sg.grp;
                ph.ulpl = htonl(PIM_MSG_HEADER_LEN);
                ph.next_hdr = IPPROTO_PIM;

                received_checksum = header->checksum;

                header->checksum = 0;
                computed_checksum = in_cksum_with_ph6(
                        &ph, header, htonl(PIM_MSG_HEADER_LEN));

                if (computed_checksum != received_checksum) {
                        if (PIM_DEBUG_PIM_PACKETS)
                                zlog_debug(
                                        "Ignoring Null Register message%pSG from %pPA due to bad checksum in Encapsulated dummy PIM header",
                                        &sg, &src_addr);
                        return 0;
                }
        }
#endif
        i_am_rp = I_am_RP(pim, sg.grp);

        if (PIM_DEBUG_PIM_REG)
                zlog_debug(
                        "Received Register message%pSG from %pPA on %s, rp: %d",
                        &sg, &src_addr, ifp->name, i_am_rp);

        if (pim_is_grp_ssm(pim_ifp->pim, sg.grp)) {
                if (pim_addr_is_any(sg.src)) {
                        zlog_warn(
                                "%s: Received Register message for Group(%pPA) is now in SSM, dropping the packet",
                                __func__, &sg.grp);
                        /* Drop Packet Silently */
                        return 0;
                }
        }

        rp_addr = (RP(pim, sg.grp))->rpf_addr;
        if (i_am_rp && (!pim_addr_cmp(dest_addr, rp_addr))) {
                sentRegisterStop = 0;

                if (pim->register_plist) {
                        struct prefix_list *plist;
                        struct prefix src;

                        plist = prefix_list_lookup(PIM_AFI,
                                                   pim->register_plist);

                        pim_addr_to_prefix(&src, sg.src);

                        if (prefix_list_apply_ext(plist, NULL, &src, true) ==
                            PREFIX_DENY) {
                                pim_register_stop_send(ifp, &sg, dest_addr,
                                                       src_addr);
                                if (PIM_DEBUG_PIM_PACKETS)
                                        zlog_debug(
                                                "%s: Sending register-stop to %pPA for %pSG due to prefix-list denial, dropping packet",
                                                __func__, &src_addr, &sg);

                                return 0;
                        }
                }

                if (*bits & PIM_REGISTER_BORDER_BIT) {
                        if (PIM_DEBUG_PIM_PACKETS)
                                zlog_debug(
                                        "%s: Received Register message with Border bit set, ignoring",
                                        __func__);

                                /* Drop Packet Silently */
                        return 0;
                }

                struct pim_upstream *upstream = pim_upstream_find(pim, &sg);
                /*
                 * If we don't have a place to send ignore the packet
                 */
                if (!upstream) {
                        upstream = pim_upstream_add(
                                pim, &sg, ifp,
                                PIM_UPSTREAM_FLAG_MASK_SRC_STREAM, __func__,
                                NULL);
                        if (!upstream) {
                                zlog_warn("Failure to create upstream state");
                                return 1;
                        }

                        upstream->upstream_register = src_addr;
                } else {
                        /*
                         * If the FHR has set a very very fast register timer
                         * there exists a possibility that the incoming NULL
                         * register
                         * is happening before we set the spt bit.  If so
                         * Do a quick check to update the counters and
                         * then set the spt bit as appropriate
                         */
                        if (upstream->sptbit != PIM_UPSTREAM_SPTBIT_TRUE) {
                                pim_mroute_update_counters(
                                        upstream->channel_oil);
                                /*
                                 * Have we seen packets?
                                 */
                                if (upstream->channel_oil->cc.oldpktcnt
                                    < upstream->channel_oil->cc.pktcnt)
                                        pim_upstream_set_sptbit(
                                                upstream,
                                                upstream->rpf.source_nexthop
                                                        .interface);
                        }
                }

                if ((upstream->sptbit == PIM_UPSTREAM_SPTBIT_TRUE)
                    || ((SwitchToSptDesiredOnRp(pim, &sg))
                        && pim_upstream_inherited_olist(pim, upstream) == 0)) {
                        pim_register_stop_send(ifp, &sg, dest_addr, src_addr);
                        sentRegisterStop = 1;
                } else {
                        if (PIM_DEBUG_PIM_REG)
                                zlog_debug("(%s) sptbit: %d", upstream->sg_str,
                                           upstream->sptbit);
                }
                if ((upstream->sptbit == PIM_UPSTREAM_SPTBIT_TRUE)
                    || (SwitchToSptDesiredOnRp(pim, &sg))) {
                        if (sentRegisterStop) {
                                pim_upstream_keep_alive_timer_start(
                                        upstream, pim->rp_keep_alive_time);
                        } else {
                                pim_upstream_keep_alive_timer_start(
                                        upstream, pim->keep_alive_time);
                        }
                }

                if (!(upstream->sptbit == PIM_UPSTREAM_SPTBIT_TRUE)
                    && !(*bits & PIM_REGISTER_NR_BIT)) {
                        // decapsulate and forward the iner packet to
                        // inherited_olist(S,G,rpt)
                        // This is taken care of by the kernel for us
                }
                pim_upstream_msdp_reg_timer_start(upstream);
        } else {
                if (PIM_DEBUG_PIM_REG) {
                        if (!i_am_rp)
                                zlog_debug("Received Register packet for %pSG, Rejecting packet because I am not the RP configured for group",
                                           &sg);
                        else
                                zlog_debug("Received Register packet for %pSG, Rejecting packet because the dst ip address is not the actual RP",
                                           &sg);
                }
                pim_register_stop_send(ifp, &sg, dest_addr, src_addr);
        }

        return 0;
}

/*
 * This routine scan all upstream and update register state and remove pimreg
 * when couldreg becomes false.
 */
void pim_reg_del_on_couldreg_fail(struct interface *ifp)
{
        struct pim_interface *pim_ifp = ifp->info;
        struct pim_instance *pim;
        struct pim_upstream *up;

        if (!pim_ifp)
                return;

        pim = pim_ifp->pim;

        frr_each (rb_pim_upstream, &pim->upstream_head, up) {
                if (ifp != up->rpf.source_nexthop.interface)
                        continue;

                if (!pim_upstream_could_register(up)
                    && (up->reg_state != PIM_REG_NOINFO)) {
                        pim_channel_del_oif(up->channel_oil, pim->regiface,
                                            PIM_OIF_FLAG_PROTO_PIM, __func__);
                        THREAD_OFF(up->t_rs_timer);
                        up->reg_state = PIM_REG_NOINFO;
                }
        }
}