diff options
Diffstat (limited to 'pimd/pim_igmp_mtrace.c')
| -rw-r--r-- | pimd/pim_igmp_mtrace.c | 861 |
1 files changed, 861 insertions, 0 deletions
diff --git a/pimd/pim_igmp_mtrace.c b/pimd/pim_igmp_mtrace.c new file mode 100644 index 0000000..f6c23c8 --- /dev/null +++ b/pimd/pim_igmp_mtrace.c @@ -0,0 +1,861 @@ +/* + * Multicast traceroute for FRRouting + * Copyright (C) 2017 Mladen Sablic + * + * 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 + */ + +/* based on draft-ietf-idmr-traceroute-ipm-07 */ + +#include <zebra.h> + +#include "pimd.h" +#include "pim_instance.h" +#include "pim_util.h" +#include "pim_sock.h" +#include "pim_rp.h" +#include "pim_oil.h" +#include "pim_ifchannel.h" +#include "pim_macro.h" +#include "pim_igmp_mtrace.h" + +static struct in_addr mtrace_primary_address(struct interface *ifp) +{ + struct connected *ifc; + struct listnode *node; + struct in_addr any; + struct pim_interface *pim_ifp; + + if (ifp->info) { + pim_ifp = ifp->info; + return pim_ifp->primary_address; + } + + any.s_addr = INADDR_ANY; + + for (ALL_LIST_ELEMENTS_RO(ifp->connected, node, ifc)) { + struct prefix *p = ifc->address; + + if (p->family != AF_INET) + continue; + + if (!CHECK_FLAG(ifc->flags, ZEBRA_IFA_SECONDARY)) + return p->u.prefix4; + /* in case no primary found, return a secondary */ + any = p->u.prefix4; + } + return any; +} + +static bool mtrace_fwd_info_weak(struct pim_instance *pim, + struct igmp_mtrace *mtracep, + struct igmp_mtrace_rsp *rspp, + struct interface **ifpp) +{ + struct pim_nexthop nexthop; + struct interface *ifp_in; + struct in_addr nh_addr; + + nh_addr.s_addr = INADDR_ANY; + + memset(&nexthop, 0, sizeof(nexthop)); + + if (!pim_nexthop_lookup(pim, &nexthop, mtracep->src_addr, 1)) { + if (PIM_DEBUG_MTRACE) + zlog_debug("mtrace not found neighbor"); + return false; + } + + if (PIM_DEBUG_MTRACE) + zlog_debug("mtrace pim_nexthop_lookup OK"); + + if (PIM_DEBUG_MTRACE) + zlog_debug("mtrace next_hop=%pPAs", &nexthop.mrib_nexthop_addr); + + nh_addr = nexthop.mrib_nexthop_addr; + + ifp_in = nexthop.interface; + + /* return interface for forwarding mtrace packets */ + *ifpp = ifp_in; + + /* 6.2.2. 4. Fill in the Incoming Interface Address... */ + rspp->incoming = mtrace_primary_address(ifp_in); + rspp->prev_hop = nh_addr; + rspp->in_count = htonl(MTRACE_UNKNOWN_COUNT); + rspp->total = htonl(MTRACE_UNKNOWN_COUNT); + rspp->rtg_proto = MTRACE_RTG_PROTO_PIM; + return true; +} + +static bool mtrace_fwd_info(struct pim_instance *pim, + struct igmp_mtrace *mtracep, + struct igmp_mtrace_rsp *rspp, + struct interface **ifpp) +{ + pim_sgaddr sg; + struct pim_upstream *up; + struct interface *ifp_in; + struct in_addr nh_addr; + uint32_t total; + + memset(&sg, 0, sizeof(sg)); + sg.src = mtracep->src_addr; + sg.grp = mtracep->grp_addr; + + up = pim_upstream_find(pim, &sg); + + if (!up) { + sg.src = PIMADDR_ANY; + up = pim_upstream_find(pim, &sg); + } + + if (!up) + return false; + + if (!up->rpf.source_nexthop.interface) { + if (PIM_DEBUG_TRACE) + zlog_debug("%s: up %s RPF is not present", __func__, + up->sg_str); + return false; + } + + ifp_in = up->rpf.source_nexthop.interface; + nh_addr = up->rpf.source_nexthop.mrib_nexthop_addr; + total = htonl(MTRACE_UNKNOWN_COUNT); + + if (PIM_DEBUG_MTRACE) + zlog_debug("fwd_info: upstream next hop=%pI4", &nh_addr); + + if (up->channel_oil) + total = up->channel_oil->cc.pktcnt; + + /* return interface for forwarding mtrace packets */ + *ifpp = ifp_in; + + /* 6.2.2. 4. Fill in the Incoming Interface Address... */ + rspp->incoming = mtrace_primary_address(ifp_in); + rspp->prev_hop = nh_addr; + rspp->in_count = htonl(MTRACE_UNKNOWN_COUNT); + rspp->total = total; + rspp->rtg_proto = MTRACE_RTG_PROTO_PIM; + + /* 6.2.2. 4. Fill in ... S, and Src Mask */ + if (!pim_addr_is_any(sg.src)) { + rspp->s = 1; + rspp->src_mask = MTRACE_SRC_MASK_SOURCE; + } else { + rspp->s = 0; + rspp->src_mask = MTRACE_SRC_MASK_GROUP; + } + + return true; +} + +static void mtrace_rsp_set_fwd_code(struct igmp_mtrace_rsp *mtrace_rspp, + enum mtrace_fwd_code fwd_code) +{ + if (mtrace_rspp->fwd_code == MTRACE_FWD_CODE_NO_ERROR) + mtrace_rspp->fwd_code = fwd_code; +} + +static void mtrace_rsp_init(struct igmp_mtrace_rsp *mtrace_rspp) +{ + mtrace_rspp->arrival = 0; + mtrace_rspp->incoming.s_addr = INADDR_ANY; + mtrace_rspp->outgoing.s_addr = INADDR_ANY; + mtrace_rspp->prev_hop.s_addr = INADDR_ANY; + mtrace_rspp->in_count = htonl(MTRACE_UNKNOWN_COUNT); + mtrace_rspp->out_count = htonl(MTRACE_UNKNOWN_COUNT); + mtrace_rspp->total = htonl(MTRACE_UNKNOWN_COUNT); + mtrace_rspp->rtg_proto = 0; + mtrace_rspp->fwd_ttl = 0; + mtrace_rspp->mbz = 0; + mtrace_rspp->s = 0; + mtrace_rspp->src_mask = 0; + mtrace_rspp->fwd_code = MTRACE_FWD_CODE_NO_ERROR; +} + +static void mtrace_rsp_debug(uint32_t qry_id, int rsp, + struct igmp_mtrace_rsp *mrspp) +{ + struct in_addr incoming = mrspp->incoming; + struct in_addr outgoing = mrspp->outgoing; + struct in_addr prev_hop = mrspp->prev_hop; + + zlog_debug( + "Rx mt(%d) qid=%ud arr=%x in=%pI4 out=%pI4 prev=%pI4 proto=%d fwd=%d", + rsp, ntohl(qry_id), mrspp->arrival, &incoming, &outgoing, + &prev_hop, mrspp->rtg_proto, mrspp->fwd_code); +} + +static void mtrace_debug(struct pim_interface *pim_ifp, + struct igmp_mtrace *mtracep, int mtrace_len) +{ + struct in_addr ga, sa, da, ra; + + ga = mtracep->grp_addr; + sa = mtracep->src_addr; + da = mtracep->dst_addr; + ra = mtracep->rsp_addr; + + zlog_debug( + "Rx mtrace packet incoming on %pI4: hops=%d type=%d size=%d, grp=%pI4, src=%pI4, dst=%pI4 rsp=%pI4 ttl=%d qid=%ud", + &pim_ifp->primary_address, mtracep->hops, mtracep->type, + mtrace_len, &ga, &sa, &da, &ra, mtracep->rsp_ttl, + ntohl(mtracep->qry_id)); + if (mtrace_len > (int)sizeof(struct igmp_mtrace)) { + + int i; + + int responses = mtrace_len - sizeof(struct igmp_mtrace); + + if ((responses % sizeof(struct igmp_mtrace_rsp)) != 0) + if (PIM_DEBUG_MTRACE) + zlog_debug( + "Mtrace response block of wrong length"); + + responses = responses / sizeof(struct igmp_mtrace_rsp); + + for (i = 0; i < responses; i++) + mtrace_rsp_debug(mtracep->qry_id, i, &mtracep->rsp[i]); + } +} + +/* 5.1 Query Arrival Time */ +static uint32_t query_arrival_time(void) +{ + struct timeval tv; + uint32_t qat; + + if (gettimeofday(&tv, NULL) < 0) { + if (PIM_DEBUG_MTRACE) + zlog_debug("Query arrival time lookup failed: errno=%d: %s", + errno, safe_strerror(errno)); + return 0; + } + /* not sure second offset correct, as I get different value */ + qat = ((tv.tv_sec + 32384) << 16) + ((tv.tv_usec << 10) / 15625); + + return qat; +} + +static int mtrace_send_packet(struct interface *ifp, + struct igmp_mtrace *mtracep, + size_t mtrace_buf_len, struct in_addr dst_addr, + struct in_addr group_addr) +{ + struct sockaddr_in to; + socklen_t tolen; + ssize_t sent; + int ret; + int fd; + uint8_t ttl; + + memset(&to, 0, sizeof(to)); + to.sin_family = AF_INET; + to.sin_addr = dst_addr; + tolen = sizeof(to); + + if (PIM_DEBUG_MTRACE) { + struct in_addr if_addr; + struct in_addr rsp_addr = mtracep->rsp_addr; + + if_addr = mtrace_primary_address(ifp); + zlog_debug("Sending mtrace packet to %pI4 on %pI4", &rsp_addr, + &if_addr); + } + + fd = pim_socket_raw(IPPROTO_IGMP); + + if (fd < 0) + return -1; + + ret = pim_socket_bind(fd, ifp); + + if (ret < 0) { + ret = -1; + goto close_fd; + } + + if (IPV4_CLASS_DE(ntohl(dst_addr.s_addr))) { + if (IPV4_MC_LINKLOCAL(ntohl(dst_addr.s_addr))) { + ttl = 1; + } else { + if (mtracep->type == PIM_IGMP_MTRACE_RESPONSE) + ttl = mtracep->rsp_ttl; + else + ttl = 64; + } + ret = setsockopt(fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, + sizeof(ttl)); + + if (ret < 0) { + if (PIM_DEBUG_MTRACE) + zlog_debug("Failed to set socket multicast TTL"); + ret = -1; + goto close_fd; + } + } + + sent = sendto(fd, (char *)mtracep, mtrace_buf_len, MSG_DONTWAIT, + (struct sockaddr *)&to, tolen); + + if (sent != (ssize_t)mtrace_buf_len) { + char dst_str[INET_ADDRSTRLEN]; + char group_str[INET_ADDRSTRLEN]; + + pim_inet4_dump("<dst?>", dst_addr, dst_str, sizeof(dst_str)); + pim_inet4_dump("<group?>", group_addr, group_str, + sizeof(group_str)); + if (sent < 0) { + if (PIM_DEBUG_MTRACE) + zlog_debug( + "Send mtrace request failed for %s on%s: group=%s msg_size=%zd: errno=%d: %s", + dst_str, ifp->name, group_str, + mtrace_buf_len, errno, + safe_strerror(errno)); + } else { + if (PIM_DEBUG_MTRACE) + zlog_debug( + "Send mtrace request failed for %s on %s: group=%s msg_size=%zd: sent=%zd", + dst_str, ifp->name, group_str, + mtrace_buf_len, sent); + } + ret = -1; + goto close_fd; + } + ret = 0; +close_fd: + close(fd); + return ret; +} + +static int mtrace_un_forward_packet(struct pim_instance *pim, struct ip *ip_hdr, + struct interface *interface) +{ + struct pim_nexthop nexthop; + struct sockaddr_in to; + struct interface *if_out; + socklen_t tolen; + int ret; + int fd; + int sent; + uint16_t checksum; + + checksum = ip_hdr->ip_sum; + + ip_hdr->ip_sum = 0; + + if (checksum != in_cksum(ip_hdr, ip_hdr->ip_hl * 4)) + return -1; + + if (ip_hdr->ip_ttl-- <= 1) + return -1; + + ip_hdr->ip_sum = in_cksum(ip_hdr, ip_hdr->ip_hl * 4); + + fd = pim_socket_raw(IPPROTO_RAW); + + if (fd < 0) + return -1; + + pim_socket_ip_hdr(fd); + + if (interface == NULL) { + memset(&nexthop, 0, sizeof(nexthop)); + if (!pim_nexthop_lookup(pim, &nexthop, ip_hdr->ip_dst, 0)) { + close(fd); + if (PIM_DEBUG_MTRACE) + zlog_debug( + "Dropping mtrace packet, no route to destination"); + return -1; + } + + if_out = nexthop.interface; + } else { + if_out = interface; + } + + ret = pim_socket_bind(fd, if_out); + + if (ret < 0) { + close(fd); + return -1; + } + + memset(&to, 0, sizeof(to)); + to.sin_family = AF_INET; + to.sin_addr = ip_hdr->ip_dst; + tolen = sizeof(to); + + sent = sendto(fd, ip_hdr, ntohs(ip_hdr->ip_len), 0, + (struct sockaddr *)&to, tolen); + + close(fd); + + if (sent < 0) { + if (PIM_DEBUG_MTRACE) + zlog_debug( + "Failed to forward mtrace packet: sendto errno=%d, %s", + errno, safe_strerror(errno)); + return -1; + } + + if (PIM_DEBUG_MTRACE) { + zlog_debug("Fwd mtrace packet len=%u to %pI4 ttl=%u", + ntohs(ip_hdr->ip_len), &ip_hdr->ip_dst, + ip_hdr->ip_ttl); + } + + return 0; +} + +static int mtrace_mc_forward_packet(struct pim_instance *pim, struct ip *ip_hdr) +{ + pim_sgaddr sg; + struct channel_oil *c_oil; + struct listnode *chnode; + struct listnode *chnextnode; + struct pim_ifchannel *ch = NULL; + int ret = -1; + + memset(&sg, 0, sizeof(sg)); + sg.grp = ip_hdr->ip_dst; + + c_oil = pim_find_channel_oil(pim, &sg); + + if (c_oil == NULL) { + if (PIM_DEBUG_MTRACE) { + zlog_debug( + "Dropping mtrace multicast packet len=%u to %pI4 ttl=%u", + ntohs(ip_hdr->ip_len), + &ip_hdr->ip_dst, ip_hdr->ip_ttl); + } + return -1; + } + if (c_oil->up == NULL) + return -1; + if (c_oil->up->ifchannels == NULL) + return -1; + for (ALL_LIST_ELEMENTS(c_oil->up->ifchannels, chnode, chnextnode, ch)) { + if (pim_macro_chisin_oiflist(ch)) { + int r; + + r = mtrace_un_forward_packet(pim, ip_hdr, + ch->interface); + if (r == 0) + ret = 0; + } + } + return ret; +} + + +static int mtrace_forward_packet(struct pim_instance *pim, struct ip *ip_hdr) +{ + if (IPV4_CLASS_DE(ntohl(ip_hdr->ip_dst.s_addr))) + return mtrace_mc_forward_packet(pim, ip_hdr); + else + return mtrace_un_forward_packet(pim, ip_hdr, NULL); +} + +static int mtrace_send_mc_response(struct pim_instance *pim, + struct igmp_mtrace *mtracep, + size_t mtrace_len) +{ + pim_sgaddr sg; + struct channel_oil *c_oil; + struct listnode *chnode; + struct listnode *chnextnode; + struct pim_ifchannel *ch = NULL; + int ret = -1; + + memset(&sg, 0, sizeof(sg)); + sg.grp = mtracep->rsp_addr; + + c_oil = pim_find_channel_oil(pim, &sg); + + if (c_oil == NULL) { + if (PIM_DEBUG_MTRACE) { + struct in_addr rsp_addr = mtracep->rsp_addr; + + zlog_debug( + "Dropping mtrace multicast response packet len=%u to %pI4", + (unsigned int)mtrace_len, &rsp_addr); + } + return -1; + } + if (c_oil->up == NULL) + return -1; + if (c_oil->up->ifchannels == NULL) + return -1; + for (ALL_LIST_ELEMENTS(c_oil->up->ifchannels, chnode, chnextnode, ch)) { + if (pim_macro_chisin_oiflist(ch)) { + int r; + + r = mtrace_send_packet(ch->interface, mtracep, + mtrace_len, mtracep->rsp_addr, + mtracep->grp_addr); + if (r == 0) + ret = 0; + } + } + return ret; +} + +/* 6.5 Sending Traceroute Responses */ +static int mtrace_send_response(struct pim_instance *pim, + struct igmp_mtrace *mtracep, size_t mtrace_len) +{ + struct pim_nexthop nexthop; + + mtracep->type = PIM_IGMP_MTRACE_RESPONSE; + + mtracep->checksum = 0; + mtracep->checksum = in_cksum((char *)mtracep, mtrace_len); + + if (IPV4_CLASS_DE(ntohl(mtracep->rsp_addr.s_addr))) { + struct pim_rpf *p_rpf; + + if (pim_rp_i_am_rp(pim, mtracep->rsp_addr)) + return mtrace_send_mc_response(pim, mtracep, + mtrace_len); + + p_rpf = pim_rp_g(pim, mtracep->rsp_addr); + + if (p_rpf == NULL) { + if (PIM_DEBUG_MTRACE) { + struct in_addr rsp_addr = mtracep->rsp_addr; + + zlog_debug("mtrace no RP for %pI4", &rsp_addr); + } + return -1; + } + nexthop = p_rpf->source_nexthop; + if (PIM_DEBUG_MTRACE) + zlog_debug("mtrace response to RP"); + } else { + memset(&nexthop, 0, sizeof(nexthop)); + /* TODO: should use unicast rib lookup */ + if (!pim_nexthop_lookup(pim, &nexthop, mtracep->rsp_addr, 1)) { + if (PIM_DEBUG_MTRACE) + zlog_debug( + "Dropped response qid=%ud, no route to response address", + mtracep->qry_id); + return -1; + } + } + + return mtrace_send_packet(nexthop.interface, mtracep, mtrace_len, + mtracep->rsp_addr, mtracep->grp_addr); +} + +int igmp_mtrace_recv_qry_req(struct gm_sock *igmp, struct ip *ip_hdr, + struct in_addr from, const char *from_str, + char *igmp_msg, int igmp_msg_len) +{ + static uint32_t qry_id, qry_src; + char mtrace_buf[MTRACE_HDR_SIZE + MTRACE_MAX_HOPS * MTRACE_RSP_SIZE]; + struct interface *ifp; + struct interface *out_ifp = NULL; + struct pim_interface *pim_ifp; + struct pim_instance *pim; + struct igmp_mtrace *mtracep; + struct igmp_mtrace_rsp *rspp; + struct in_addr nh_addr; + enum mtrace_fwd_code fwd_code = MTRACE_FWD_CODE_NO_ERROR; + size_t r_len; + int last_rsp_ind = 0; + size_t mtrace_len; + uint16_t recv_checksum; + uint16_t checksum; + bool reached_source; + bool fwd_info; + + ifp = igmp->interface; + pim_ifp = ifp->info; + pim = pim_ifp->pim; + + /* + * 6. Router Behaviour + * Check if mtrace packet is addressed elsewhere and forward, + * if applicable + */ + if (!IPV4_CLASS_DE(ntohl(ip_hdr->ip_dst.s_addr))) + if (!if_address_is_local(&ip_hdr->ip_dst, AF_INET, + pim->vrf->vrf_id)) + return mtrace_forward_packet(pim, ip_hdr); + + if (igmp_msg_len < (int)sizeof(struct igmp_mtrace)) { + if (PIM_DEBUG_MTRACE) + zlog_debug( + "Recv mtrace packet from %s on %s: too short, len=%d, min=%zu", + from_str, ifp->name, igmp_msg_len, + sizeof(struct igmp_mtrace)); + return -1; + } + + mtracep = (struct igmp_mtrace *)igmp_msg; + + recv_checksum = mtracep->checksum; + + mtracep->checksum = 0; + + checksum = in_cksum(igmp_msg, igmp_msg_len); + + if (recv_checksum != checksum) { + if (PIM_DEBUG_MTRACE) + zlog_debug( + "Recv mtrace packet from %s on %s: checksum mismatch: received=%x computed=%x", + from_str, ifp->name, recv_checksum, checksum); + return -1; + } + + /* Collecting IGMP Rx stats */ + igmp->igmp_stats.mtrace_req++; + + if (PIM_DEBUG_MTRACE) + mtrace_debug(pim_ifp, mtracep, igmp_msg_len); + + /* subtract header from message length */ + r_len = igmp_msg_len - sizeof(struct igmp_mtrace); + + /* Classify mtrace packet, check if it is a query */ + if (!r_len) { + if (PIM_DEBUG_MTRACE) + zlog_debug("Received IGMP multicast traceroute query"); + + /* 6.1.1 Packet verification */ + if (!pim_if_connected_to_source(ifp, mtracep->dst_addr)) { + if (IPV4_CLASS_DE(ntohl(ip_hdr->ip_dst.s_addr))) { + if (PIM_DEBUG_MTRACE) + zlog_debug( + "Dropping multicast query on wrong interface"); + return -1; + } + /* Unicast query on wrong interface */ + fwd_code = MTRACE_FWD_CODE_WRONG_IF; + if (PIM_DEBUG_MTRACE) + zlog_debug("Multicast query on wrong interface"); + } + if (qry_id == mtracep->qry_id && qry_src == from.s_addr) { + if (PIM_DEBUG_MTRACE) + zlog_debug( + "Dropping multicast query with duplicate source and id"); + return -1; + } + qry_id = mtracep->qry_id; + qry_src = from.s_addr; + } + /* if response fields length is equal to a whole number of responses */ + else if ((r_len % sizeof(struct igmp_mtrace_rsp)) == 0) { + r_len = igmp_msg_len - sizeof(struct igmp_mtrace); + + if (r_len != 0) + last_rsp_ind = r_len / sizeof(struct igmp_mtrace_rsp); + if (last_rsp_ind > MTRACE_MAX_HOPS) { + if (PIM_DEBUG_MTRACE) + zlog_debug("Mtrace request of excessive size"); + return -1; + } + } else { + if (PIM_DEBUG_MTRACE) + zlog_debug( + "Recv mtrace packet from %s on %s: invalid length %d", + from_str, ifp->name, igmp_msg_len); + return -1; + } + + /* 6.2.1 Packet Verification - drop not link-local multicast */ + if (IPV4_CLASS_DE(ntohl(ip_hdr->ip_dst.s_addr)) + && !IPV4_MC_LINKLOCAL(ntohl(ip_hdr->ip_dst.s_addr))) { + if (PIM_DEBUG_MTRACE) + zlog_debug( + "Recv mtrace packet from %s on %s: not link-local multicast %pI4", + from_str, ifp->name, &ip_hdr->ip_dst); + return -1; + } + + /* 6.2.2. Normal Processing */ + + /* 6.2.2. 1. If there is room in the current buffer? */ + + if (last_rsp_ind == MTRACE_MAX_HOPS) { + /* ...there was no room... */ + mtracep->rsp[MTRACE_MAX_HOPS - 1].fwd_code = + MTRACE_FWD_CODE_NO_SPACE; + return mtrace_send_response(pim_ifp->pim, mtracep, + igmp_msg_len); + } + + /* ...insert new response block... */ + + /* calculate new mtrace lenght with extra response */ + mtrace_len = igmp_msg_len + sizeof(struct igmp_mtrace_rsp); + + /* copy received query/request */ + memcpy(mtrace_buf, igmp_msg, igmp_msg_len); + + /* repoint mtracep pointer to copy */ + mtracep = (struct igmp_mtrace *)mtrace_buf; + + /* pointer for extra response field to be filled in */ + rspp = &mtracep->rsp[last_rsp_ind]; + + /* initialize extra response field */ + mtrace_rsp_init(rspp); + + /* carry over any error noted when receiving the query */ + rspp->fwd_code = fwd_code; + + /* ...and fill in Query Arrival Time... */ + rspp->arrival = htonl(query_arrival_time()); + rspp->outgoing = pim_ifp->primary_address; + rspp->out_count = htonl(MTRACE_UNKNOWN_COUNT); + rspp->fwd_ttl = 1; + + /* 6.2.2. 2. Attempt to determine the forwarding information... */ + + if (mtracep->grp_addr.s_addr != INADDR_ANY) + fwd_info = mtrace_fwd_info(pim, mtracep, rspp, &out_ifp); + else + fwd_info = mtrace_fwd_info_weak(pim, mtracep, rspp, &out_ifp); + + /* 6.2.2 3. If no forwarding information... */ + if (!fwd_info) { + if (PIM_DEBUG_MTRACE) + zlog_debug("mtrace not found multicast state"); + mtrace_rsp_set_fwd_code(rspp, MTRACE_FWD_CODE_NO_ROUTE); + /* 6.2.2. 3. forward the packet to requester */ + return mtrace_send_response(pim, mtracep, mtrace_len); + } + + nh_addr = rspp->prev_hop; + + reached_source = false; + + if (nh_addr.s_addr == INADDR_ANY) { + /* no pim? i.e. 7.5.3. No Previous Hop */ + if (!out_ifp->info) { + if (PIM_DEBUG_MTRACE) + zlog_debug("mtrace not found incoming if w/ pim"); + mtrace_rsp_set_fwd_code(rspp, + MTRACE_FWD_CODE_NO_MULTICAST); + return mtrace_send_response(pim, mtracep, mtrace_len); + } + /* reached source? i.e. 7.5.1 Arriving at source */ + if (pim_if_connected_to_source(out_ifp, mtracep->src_addr)) { + reached_source = true; + rspp->prev_hop = mtracep->src_addr; + } + /* + * 6.4 Forwarding Traceroute Requests: + * Previous-hop router not known, + * packet is sent to an appropriate multicast address + */ + (void)inet_aton(MCAST_ALL_ROUTERS, &nh_addr); + } + + /* 6.2.2 8. If this router is the Rendez-vous Point */ + if (pim_rp_i_am_rp(pim, mtracep->grp_addr)) { + mtrace_rsp_set_fwd_code(rspp, MTRACE_FWD_CODE_REACHED_RP); + /* 7.7.1. PIM-SM ...RP has not performed source-specific join */ + if (rspp->src_mask == MTRACE_SRC_MASK_GROUP) + return mtrace_send_response(pim, mtracep, mtrace_len); + } + + /* + * 6.4 Forwarding Traceroute Requests: the number of response + * blocks exceeds number of responses, so forward to the requester. + */ + if (mtracep->hops <= (last_rsp_ind + 1)) + return mtrace_send_response(pim, mtracep, mtrace_len); + + /* 7.5.1. Arriving at source: terminate trace */ + if (reached_source) + return mtrace_send_response(pim, mtracep, mtrace_len); + + mtracep->checksum = 0; + + mtracep->checksum = in_cksum(mtrace_buf, mtrace_len); + + /* 6.4 Forwarding Traceroute Requests: response blocks less than req. */ + return mtrace_send_packet(out_ifp, mtracep, mtrace_len, nh_addr, + mtracep->grp_addr); +} + +/* 6.3. Traceroute responses */ +int igmp_mtrace_recv_response(struct gm_sock *igmp, struct ip *ip_hdr, + struct in_addr from, const char *from_str, + char *igmp_msg, int igmp_msg_len) +{ + static uint32_t qry_id, rsp_dst; + struct interface *ifp; + struct pim_interface *pim_ifp; + struct pim_instance *pim; + struct igmp_mtrace *mtracep; + uint16_t recv_checksum; + uint16_t checksum; + + ifp = igmp->interface; + pim_ifp = ifp->info; + pim = pim_ifp->pim; + + if (igmp_msg_len < (int)sizeof(struct igmp_mtrace)) { + if (PIM_DEBUG_MTRACE) + zlog_debug( + "Recv mtrace packet from %s on %s: too short, len=%d, min=%zu", + from_str, ifp->name, igmp_msg_len, + sizeof(struct igmp_mtrace)); + return -1; + } + + mtracep = (struct igmp_mtrace *)igmp_msg; + + recv_checksum = mtracep->checksum; + + mtracep->checksum = 0; + + checksum = in_cksum(igmp_msg, igmp_msg_len); + + if (recv_checksum != checksum) { + if (PIM_DEBUG_MTRACE) + zlog_debug( + "Recv mtrace response from %s on %s: checksum mismatch: received=%x computed=%x", + from_str, ifp->name, recv_checksum, checksum); + return -1; + } + + mtracep->checksum = checksum; + + /* Collecting IGMP Rx stats */ + igmp->igmp_stats.mtrace_rsp++; + + if (PIM_DEBUG_MTRACE) + mtrace_debug(pim_ifp, mtracep, igmp_msg_len); + + /* Drop duplicate packets */ + if (qry_id == mtracep->qry_id && rsp_dst == ip_hdr->ip_dst.s_addr) { + if (PIM_DEBUG_MTRACE) + zlog_debug("duplicate mtrace response packet dropped"); + return -1; + } + + qry_id = mtracep->qry_id; + rsp_dst = ip_hdr->ip_dst.s_addr; + + return mtrace_forward_packet(pim, ip_hdr); +} |