/* * BIRD -- OSPF * * (c) 1999--2004 Ondrej Filip <feela@network.cz> * (c) 2009--2014 Ondrej Zajicek <santiago@crfreenet.org> * (c) 2009--2014 CZ.NIC z.s.p.o. * * Can be freely distributed and used under the terms of the GNU GPL. */ #include "ospf.h" struct ospf_hello2_packet { struct ospf_packet hdr; union ospf_auth2 auth; u32 netmask; u16 helloint; u8 options; u8 priority; u32 deadint; u32 dr; u32 bdr; u32 neighbors[]; }; struct ospf_hello3_packet { struct ospf_packet hdr; u32 iface_id; u32 options; u16 helloint; u16 deadint; u32 dr; u32 bdr; u32 neighbors[]; }; uint ospf_hello3_options(struct ospf_packet *pkt) { struct ospf_hello3_packet *ps = (void *) pkt; return ntohl(ps->options) & 0x00FFFFFF; } void ospf_send_hello(struct ospf_iface *ifa, int kind, struct ospf_neighbor *dirn) { struct ospf_proto *p = ifa->oa->po; struct ospf_packet *pkt; struct ospf_neighbor *neigh, *n1; struct nbma_node *nb; u32 *neighbors; uint length; int i, max; if (ifa->state <= OSPF_IS_LOOP) return; if (ifa->stub) return; pkt = ospf_tx_buffer(ifa); ospf_pkt_fill_hdr(ifa, pkt, HELLO_P); if (ospf_is_v2(p)) { struct ospf_hello2_packet *ps = (void *) pkt; if ((ifa->type == OSPF_IT_VLINK) || ((ifa->type == OSPF_IT_PTP) && !ifa->ptp_netmask)) ps->netmask = 0; else ps->netmask = htonl(u32_mkmask(ifa->addr->prefix.pxlen)); ps->helloint = ntohs(ifa->helloint); ps->options = ifa->oa->options & HELLO2_OPT_MASK; ps->priority = ifa->priority; ps->deadint = htonl(ifa->deadint); ps->dr = htonl(ipa_to_u32(ifa->drip)); ps->bdr = htonl(ipa_to_u32(ifa->bdrip)); length = sizeof(struct ospf_hello2_packet); neighbors = ps->neighbors; } else { struct ospf_hello3_packet *ps = (void *) pkt; u32 options = ifa->oa->options | (ifa->autype == OSPF_AUTH_CRYPT ? OPT_AT : 0); ps->iface_id = htonl(ifa->iface_id); ps->options = ntohl((options & HELLO3_OPT_MASK) | (ifa->priority << 24)); ps->helloint = ntohs(ifa->helloint); ps->deadint = htons(ifa->deadint); ps->dr = htonl(ifa->drid); ps->bdr = htonl(ifa->bdrid); length = sizeof(struct ospf_hello3_packet); neighbors = ps->neighbors; } i = 0; max = (ospf_pkt_maxsize(ifa) - length) / sizeof(u32); /* Fill all neighbors */ if (kind != OHS_SHUTDOWN) { WALK_LIST(neigh, ifa->neigh_list) { if (i == max) { log(L_WARN "%s: Too many neighbors on %s", p->p.name, ifa->ifname); break; } neighbors[i] = htonl(neigh->rid); i++; } } length += i * sizeof(u32); pkt->length = htons(length); OSPF_TRACE(D_PACKETS, "HELLO packet sent via %s", ifa->ifname); switch(ifa->type) { case OSPF_IT_BCAST: case OSPF_IT_PTP: ospf_send_to_all(ifa); break; case OSPF_IT_NBMA: if (dirn) /* Response to received hello */ { ospf_send_to(ifa, dirn->ip); break; } int to_all = ifa->state > OSPF_IS_DROTHER; int me_elig = ifa->priority > 0; if (kind == OHS_POLL) /* Poll timer */ { WALK_LIST(nb, ifa->nbma_list) if (!nb->found && (to_all || (me_elig && nb->eligible))) ospf_send_to(ifa, nb->ip); } else /* Hello timer */ { WALK_LIST(n1, ifa->neigh_list) if (to_all || (me_elig && (n1->priority > 0)) || (n1->rid == ifa->drid) || (n1->rid == ifa->bdrid)) ospf_send_to(ifa, n1->ip); } break; case OSPF_IT_PTMP: WALK_LIST(n1, ifa->neigh_list) ospf_send_to(ifa, n1->ip); WALK_LIST(nb, ifa->nbma_list) if (!nb->found) ospf_send_to(ifa, nb->ip); /* If there is no other target, we also send HELLO packet to the other end */ if (ipa_nonzero(ifa->addr->opposite) && !ifa->strictnbma && EMPTY_LIST(ifa->neigh_list) && EMPTY_LIST(ifa->nbma_list)) ospf_send_to(ifa, ifa->addr->opposite); break; case OSPF_IT_VLINK: ospf_send_to(ifa, ifa->vip); break; default: bug("Bug in ospf_send_hello()"); } } void ospf_receive_hello(struct ospf_packet *pkt, struct ospf_iface *ifa, struct ospf_neighbor *n, ip_addr faddr) { struct ospf_proto *p = ifa->oa->po; const char *err_dsc = NULL; u32 rcv_iface_id, rcv_helloint, rcv_deadint, rcv_dr, rcv_bdr; uint rcv_options, rcv_priority; uint loc_options = ifa->oa->options; u32 *neighbors; u32 neigh_count; uint plen, i, err_val = 0; /* RFC 2328 10.5 */ /* * We may not yet have the associate neighbor, so we use Router ID from the * packet instead of one from the neighbor structure for log messages. */ u32 rcv_rid = ntohl(pkt->routerid); OSPF_TRACE(D_PACKETS, "HELLO packet received from nbr %R on %s", rcv_rid, ifa->ifname); plen = ntohs(pkt->length); if (ospf_is_v2(p)) { struct ospf_hello2_packet *ps = (void *) pkt; if (plen < sizeof(struct ospf_hello2_packet)) DROP("too short", plen); rcv_iface_id = 0; rcv_helloint = ntohs(ps->helloint); rcv_deadint = ntohl(ps->deadint); rcv_dr = ntohl(ps->dr); rcv_bdr = ntohl(ps->bdr); rcv_options = ps->options; rcv_priority = ps->priority; int pxlen = u32_masklen(ntohl(ps->netmask)); if (pxlen < 0) DROP("prefix garbled", ntohl(ps->netmask)); if ((ifa->type != OSPF_IT_VLINK) && (ifa->type != OSPF_IT_PTP) && ((uint) pxlen != ifa->addr->prefix.pxlen)) DROP("prefix length mismatch", pxlen); neighbors = ps->neighbors; neigh_count = (plen - sizeof(struct ospf_hello2_packet)) / sizeof(u32); } else /* OSPFv3 */ { struct ospf_hello3_packet *ps = (void *) pkt; if (plen < sizeof(struct ospf_hello3_packet)) DROP("too short", plen); rcv_iface_id = ntohl(ps->iface_id); rcv_helloint = ntohs(ps->helloint); rcv_deadint = ntohs(ps->deadint); rcv_dr = ntohl(ps->dr); rcv_bdr = ntohl(ps->bdr); rcv_options = ntohl(ps->options) & 0x00FFFFFF; rcv_priority = ntohl(ps->options) >> 24; neighbors = ps->neighbors; neigh_count = (plen - sizeof(struct ospf_hello3_packet)) / sizeof(u32); } if (rcv_helloint != ifa->helloint) DROP("hello interval mismatch", rcv_helloint); if (rcv_deadint != ifa->deadint) DROP("dead interval mismatch", rcv_deadint); /* Check whether bits E, N match */ if ((rcv_options ^ loc_options) & (OPT_E | OPT_N)) DROP("area type mismatch", rcv_options); /* RFC 5838 2.4 - AF-bit check unless on IPv6 unicast */ if ((loc_options & OPT_AF) && !(loc_options & OPT_V6) && !(rcv_options & OPT_AF)) DROP("AF-bit mismatch", rcv_options); /* Check consistency of existing neighbor entry */ if (n) { uint t = ifa->type; if (ospf_is_v2(p) && ((t == OSPF_IT_BCAST) || (t == OSPF_IT_NBMA) || (t == OSPF_IT_PTMP))) { /* Neighbor identified by IP address; Router ID may change */ if (n->rid != rcv_rid) { OSPF_TRACE(D_EVENTS, "Neighbor %R on %s changed Router ID to %R", n->rid, ifa->ifname, rcv_rid); ospf_neigh_sm(n, INM_KILLNBR); n = NULL; } } else /* OSPFv3 or OSPFv2/PtP */ { /* Neighbor identified by Router ID; IP address may change */ if (!ipa_equal(faddr, n->ip)) { OSPF_TRACE(D_EVENTS, "Neighbor %R on %s changed IP address to %I", n->rid, ifa->ifname, faddr); n->ip = faddr; } } /* Update RFC 7166 authentication trailer flag */ if (ospf_is_v3(p) && ((rcv_options ^ n->options) & OPT_AT)) { OSPF_TRACE(D_EVENTS, "Neighbor %R on %s %s authentication", n->rid, ifa->ifname, (rcv_options & OPT_AT) ? "enabled" : "disabled"); n->options = (n->options & ~OPT_AT) | (rcv_options & OPT_AT); } } if (!n) { if ((ifa->type == OSPF_IT_NBMA) || (ifa->type == OSPF_IT_PTMP)) { struct nbma_node *nn = find_nbma_node(ifa, faddr); if (!nn && ifa->strictnbma) DROP1("new neighbor denied"); if (nn && (ifa->type == OSPF_IT_NBMA) && (((rcv_priority == 0) && nn->eligible) || ((rcv_priority > 0) && !nn->eligible))) DROP("eligibility mismatch", rcv_priority); if (nn) nn->found = 1; } OSPF_TRACE(D_EVENTS, "New neighbor %R on %s, IP address %I", rcv_rid, ifa->ifname, faddr); n = ospf_neighbor_new(ifa); n->rid = rcv_rid; n->ip = faddr; n->dr = rcv_dr; n->bdr = rcv_bdr; n->priority = rcv_priority; n->iface_id = rcv_iface_id; if (ospf_is_v3(p)) n->options = rcv_options & OPT_AT; if (n->ifa->cf->bfd) ospf_neigh_update_bfd(n, n->ifa->bfd); } u32 n_id = ospf_is_v2(p) ? ipa_to_u32(n->ip) : n->rid; u32 old_dr = n->dr; u32 old_bdr = n->bdr; u32 old_priority = n->priority; u32 old_iface_id = n->iface_id; n->dr = rcv_dr; n->bdr = rcv_bdr; n->priority = rcv_priority; n->iface_id = rcv_iface_id; /* Update inactivity timer */ ospf_neigh_sm(n, INM_HELLOREC); /* RFC 2328 9.5.1 - non-eligible routers reply to hello on NBMA nets */ if (ifa->type == OSPF_IT_NBMA) if ((ifa->priority == 0) && (n->priority > 0)) ospf_send_hello(n->ifa, OHS_HELLO, n); /* Examine list of neighbors */ for (i = 0; i < neigh_count; i++) if (neighbors[i] == htonl(p->router_id)) goto found_self; ospf_neigh_sm(n, INM_1WAYREC); return; found_self: ospf_neigh_sm(n, INM_2WAYREC); if (n->iface_id != old_iface_id) { /* If neighbor is DR, also update cached DR interface ID */ if (ifa->drid == n->rid) ifa->dr_iface_id = n->iface_id; /* RFC 5340 4.4.3 Event 4 - change of neighbor's interface ID */ ospf_notify_rt_lsa(ifa->oa); /* Missed in RFC 5340 4.4.3 Event 4 - (Px-)Net-LSA uses iface_id to ref Link-LSAs */ ospf_notify_net_lsa(ifa); } if (ifa->state == OSPF_IS_WAITING) { /* Neighbor is declaring itself DR (and there is no BDR) or as BDR */ if (((n->dr == n_id) && (n->bdr == 0)) || (n->bdr == n_id)) ospf_iface_sm(ifa, ISM_BACKS); } else if (ifa->state >= OSPF_IS_DROTHER) { /* Neighbor changed priority or started/stopped declaring itself as DR/BDR */ if ((n->priority != old_priority) || ((n->dr == n_id) && (old_dr != n_id)) || ((n->dr != n_id) && (old_dr == n_id)) || ((n->bdr == n_id) && (old_bdr != n_id)) || ((n->bdr != n_id) && (old_bdr == n_id))) ospf_iface_sm(ifa, ISM_NEICH); } return; drop: LOG_PKT("Bad HELLO packet from nbr %R on %s - %s (%u)", rcv_rid, ifa->ifname, err_dsc, err_val); }