Annotation of embedaddon/bird2/proto/ospf/hello.c, revision 1.1
1.1 ! misho 1: /*
! 2: * BIRD -- OSPF
! 3: *
! 4: * (c) 1999--2004 Ondrej Filip <feela@network.cz>
! 5: * (c) 2009--2014 Ondrej Zajicek <santiago@crfreenet.org>
! 6: * (c) 2009--2014 CZ.NIC z.s.p.o.
! 7: *
! 8: * Can be freely distributed and used under the terms of the GNU GPL.
! 9: */
! 10:
! 11: #include "ospf.h"
! 12:
! 13:
! 14: struct ospf_hello2_packet
! 15: {
! 16: struct ospf_packet hdr;
! 17: union ospf_auth2 auth;
! 18:
! 19: u32 netmask;
! 20: u16 helloint;
! 21: u8 options;
! 22: u8 priority;
! 23: u32 deadint;
! 24: u32 dr;
! 25: u32 bdr;
! 26:
! 27: u32 neighbors[];
! 28: };
! 29:
! 30: struct ospf_hello3_packet
! 31: {
! 32: struct ospf_packet hdr;
! 33:
! 34: u32 iface_id;
! 35: u32 options;
! 36: u16 helloint;
! 37: u16 deadint;
! 38: u32 dr;
! 39: u32 bdr;
! 40:
! 41: u32 neighbors[];
! 42: };
! 43:
! 44:
! 45: uint
! 46: ospf_hello3_options(struct ospf_packet *pkt)
! 47: {
! 48: struct ospf_hello3_packet *ps = (void *) pkt;
! 49: return ntohl(ps->options) & 0x00FFFFFF;
! 50: }
! 51:
! 52: void
! 53: ospf_send_hello(struct ospf_iface *ifa, int kind, struct ospf_neighbor *dirn)
! 54: {
! 55: struct ospf_proto *p = ifa->oa->po;
! 56: struct ospf_packet *pkt;
! 57: struct ospf_neighbor *neigh, *n1;
! 58: struct nbma_node *nb;
! 59: u32 *neighbors;
! 60: uint length;
! 61: int i, max;
! 62:
! 63: if (ifa->state <= OSPF_IS_LOOP)
! 64: return;
! 65:
! 66: if (ifa->stub)
! 67: return;
! 68:
! 69:
! 70: pkt = ospf_tx_buffer(ifa);
! 71: ospf_pkt_fill_hdr(ifa, pkt, HELLO_P);
! 72:
! 73: if (ospf_is_v2(p))
! 74: {
! 75: struct ospf_hello2_packet *ps = (void *) pkt;
! 76:
! 77: if ((ifa->type == OSPF_IT_VLINK) ||
! 78: ((ifa->type == OSPF_IT_PTP) && !ifa->ptp_netmask))
! 79: ps->netmask = 0;
! 80: else
! 81: ps->netmask = htonl(u32_mkmask(ifa->addr->prefix.pxlen));
! 82:
! 83: ps->helloint = ntohs(ifa->helloint);
! 84: ps->options = ifa->oa->options & HELLO2_OPT_MASK;
! 85: ps->priority = ifa->priority;
! 86: ps->deadint = htonl(ifa->deadint);
! 87: ps->dr = htonl(ipa_to_u32(ifa->drip));
! 88: ps->bdr = htonl(ipa_to_u32(ifa->bdrip));
! 89:
! 90: length = sizeof(struct ospf_hello2_packet);
! 91: neighbors = ps->neighbors;
! 92: }
! 93: else
! 94: {
! 95: struct ospf_hello3_packet *ps = (void *) pkt;
! 96: u32 options = ifa->oa->options | (ifa->autype == OSPF_AUTH_CRYPT ? OPT_AT : 0);
! 97:
! 98: ps->iface_id = htonl(ifa->iface_id);
! 99: ps->options = ntohl((options & HELLO3_OPT_MASK) | (ifa->priority << 24));
! 100: ps->helloint = ntohs(ifa->helloint);
! 101: ps->deadint = htons(ifa->deadint);
! 102: ps->dr = htonl(ifa->drid);
! 103: ps->bdr = htonl(ifa->bdrid);
! 104:
! 105: length = sizeof(struct ospf_hello3_packet);
! 106: neighbors = ps->neighbors;
! 107: }
! 108:
! 109: i = 0;
! 110: max = (ospf_pkt_maxsize(ifa) - length) / sizeof(u32);
! 111:
! 112: /* Fill all neighbors */
! 113: if (kind != OHS_SHUTDOWN)
! 114: {
! 115: WALK_LIST(neigh, ifa->neigh_list)
! 116: {
! 117: if (i == max)
! 118: {
! 119: log(L_WARN "%s: Too many neighbors on %s", p->p.name, ifa->ifname);
! 120: break;
! 121: }
! 122: neighbors[i] = htonl(neigh->rid);
! 123: i++;
! 124: }
! 125: }
! 126:
! 127: length += i * sizeof(u32);
! 128: pkt->length = htons(length);
! 129:
! 130: OSPF_TRACE(D_PACKETS, "HELLO packet sent via %s", ifa->ifname);
! 131:
! 132: switch(ifa->type)
! 133: {
! 134: case OSPF_IT_BCAST:
! 135: case OSPF_IT_PTP:
! 136: ospf_send_to_all(ifa);
! 137: break;
! 138:
! 139: case OSPF_IT_NBMA:
! 140: if (dirn) /* Response to received hello */
! 141: {
! 142: ospf_send_to(ifa, dirn->ip);
! 143: break;
! 144: }
! 145:
! 146: int to_all = ifa->state > OSPF_IS_DROTHER;
! 147: int me_elig = ifa->priority > 0;
! 148:
! 149: if (kind == OHS_POLL) /* Poll timer */
! 150: {
! 151: WALK_LIST(nb, ifa->nbma_list)
! 152: if (!nb->found && (to_all || (me_elig && nb->eligible)))
! 153: ospf_send_to(ifa, nb->ip);
! 154: }
! 155: else /* Hello timer */
! 156: {
! 157: WALK_LIST(n1, ifa->neigh_list)
! 158: if (to_all || (me_elig && (n1->priority > 0)) ||
! 159: (n1->rid == ifa->drid) || (n1->rid == ifa->bdrid))
! 160: ospf_send_to(ifa, n1->ip);
! 161: }
! 162: break;
! 163:
! 164: case OSPF_IT_PTMP:
! 165: WALK_LIST(n1, ifa->neigh_list)
! 166: ospf_send_to(ifa, n1->ip);
! 167:
! 168: WALK_LIST(nb, ifa->nbma_list)
! 169: if (!nb->found)
! 170: ospf_send_to(ifa, nb->ip);
! 171:
! 172: /* If there is no other target, we also send HELLO packet to the other end */
! 173: if (ipa_nonzero(ifa->addr->opposite) && !ifa->strictnbma &&
! 174: EMPTY_LIST(ifa->neigh_list) && EMPTY_LIST(ifa->nbma_list))
! 175: ospf_send_to(ifa, ifa->addr->opposite);
! 176: break;
! 177:
! 178: case OSPF_IT_VLINK:
! 179: ospf_send_to(ifa, ifa->vip);
! 180: break;
! 181:
! 182: default:
! 183: bug("Bug in ospf_send_hello()");
! 184: }
! 185: }
! 186:
! 187:
! 188: void
! 189: ospf_receive_hello(struct ospf_packet *pkt, struct ospf_iface *ifa,
! 190: struct ospf_neighbor *n, ip_addr faddr)
! 191: {
! 192: struct ospf_proto *p = ifa->oa->po;
! 193: const char *err_dsc = NULL;
! 194: u32 rcv_iface_id, rcv_helloint, rcv_deadint, rcv_dr, rcv_bdr;
! 195: uint rcv_options, rcv_priority;
! 196: uint loc_options = ifa->oa->options;
! 197: u32 *neighbors;
! 198: u32 neigh_count;
! 199: uint plen, i, err_val = 0;
! 200:
! 201: /* RFC 2328 10.5 */
! 202:
! 203: /*
! 204: * We may not yet have the associate neighbor, so we use Router ID from the
! 205: * packet instead of one from the neighbor structure for log messages.
! 206: */
! 207: u32 rcv_rid = ntohl(pkt->routerid);
! 208: OSPF_TRACE(D_PACKETS, "HELLO packet received from nbr %R on %s", rcv_rid, ifa->ifname);
! 209:
! 210: plen = ntohs(pkt->length);
! 211:
! 212: if (ospf_is_v2(p))
! 213: {
! 214: struct ospf_hello2_packet *ps = (void *) pkt;
! 215:
! 216: if (plen < sizeof(struct ospf_hello2_packet))
! 217: DROP("too short", plen);
! 218:
! 219: rcv_iface_id = 0;
! 220: rcv_helloint = ntohs(ps->helloint);
! 221: rcv_deadint = ntohl(ps->deadint);
! 222: rcv_dr = ntohl(ps->dr);
! 223: rcv_bdr = ntohl(ps->bdr);
! 224: rcv_options = ps->options;
! 225: rcv_priority = ps->priority;
! 226:
! 227: int pxlen = u32_masklen(ntohl(ps->netmask));
! 228: if (pxlen < 0)
! 229: DROP("prefix garbled", ntohl(ps->netmask));
! 230:
! 231: if ((ifa->type != OSPF_IT_VLINK) &&
! 232: (ifa->type != OSPF_IT_PTP) &&
! 233: ((uint) pxlen != ifa->addr->prefix.pxlen))
! 234: DROP("prefix length mismatch", pxlen);
! 235:
! 236: neighbors = ps->neighbors;
! 237: neigh_count = (plen - sizeof(struct ospf_hello2_packet)) / sizeof(u32);
! 238: }
! 239: else /* OSPFv3 */
! 240: {
! 241: struct ospf_hello3_packet *ps = (void *) pkt;
! 242:
! 243: if (plen < sizeof(struct ospf_hello3_packet))
! 244: DROP("too short", plen);
! 245:
! 246: rcv_iface_id = ntohl(ps->iface_id);
! 247: rcv_helloint = ntohs(ps->helloint);
! 248: rcv_deadint = ntohs(ps->deadint);
! 249: rcv_dr = ntohl(ps->dr);
! 250: rcv_bdr = ntohl(ps->bdr);
! 251: rcv_options = ntohl(ps->options) & 0x00FFFFFF;
! 252: rcv_priority = ntohl(ps->options) >> 24;
! 253:
! 254: neighbors = ps->neighbors;
! 255: neigh_count = (plen - sizeof(struct ospf_hello3_packet)) / sizeof(u32);
! 256: }
! 257:
! 258: if (rcv_helloint != ifa->helloint)
! 259: DROP("hello interval mismatch", rcv_helloint);
! 260:
! 261: if (rcv_deadint != ifa->deadint)
! 262: DROP("dead interval mismatch", rcv_deadint);
! 263:
! 264: /* Check whether bits E, N match */
! 265: if ((rcv_options ^ loc_options) & (OPT_E | OPT_N))
! 266: DROP("area type mismatch", rcv_options);
! 267:
! 268: /* RFC 5838 2.4 - AF-bit check unless on IPv6 unicast */
! 269: if ((loc_options & OPT_AF) && !(loc_options & OPT_V6) && !(rcv_options & OPT_AF))
! 270: DROP("AF-bit mismatch", rcv_options);
! 271:
! 272: /* Check consistency of existing neighbor entry */
! 273: if (n)
! 274: {
! 275: uint t = ifa->type;
! 276: if (ospf_is_v2(p) && ((t == OSPF_IT_BCAST) || (t == OSPF_IT_NBMA) || (t == OSPF_IT_PTMP)))
! 277: {
! 278: /* Neighbor identified by IP address; Router ID may change */
! 279: if (n->rid != rcv_rid)
! 280: {
! 281: OSPF_TRACE(D_EVENTS, "Neighbor %R on %s changed Router ID to %R",
! 282: n->rid, ifa->ifname, rcv_rid);
! 283: ospf_neigh_sm(n, INM_KILLNBR);
! 284: n = NULL;
! 285: }
! 286: }
! 287: else /* OSPFv3 or OSPFv2/PtP */
! 288: {
! 289: /* Neighbor identified by Router ID; IP address may change */
! 290: if (!ipa_equal(faddr, n->ip))
! 291: {
! 292: OSPF_TRACE(D_EVENTS, "Neighbor %R on %s changed IP address to %I",
! 293: n->rid, ifa->ifname, faddr);
! 294: n->ip = faddr;
! 295: }
! 296: }
! 297: }
! 298:
! 299: if (!n)
! 300: {
! 301: if ((ifa->type == OSPF_IT_NBMA) || (ifa->type == OSPF_IT_PTMP))
! 302: {
! 303: struct nbma_node *nn = find_nbma_node(ifa, faddr);
! 304:
! 305: if (!nn && ifa->strictnbma)
! 306: DROP1("new neighbor denied");
! 307:
! 308: if (nn && (ifa->type == OSPF_IT_NBMA) &&
! 309: (((rcv_priority == 0) && nn->eligible) ||
! 310: ((rcv_priority > 0) && !nn->eligible)))
! 311: DROP("eligibility mismatch", rcv_priority);
! 312:
! 313: if (nn)
! 314: nn->found = 1;
! 315: }
! 316:
! 317: OSPF_TRACE(D_EVENTS, "New neighbor %R on %s, IP address %I",
! 318: rcv_rid, ifa->ifname, faddr);
! 319:
! 320: n = ospf_neighbor_new(ifa);
! 321:
! 322: n->rid = rcv_rid;
! 323: n->ip = faddr;
! 324: n->dr = rcv_dr;
! 325: n->bdr = rcv_bdr;
! 326: n->priority = rcv_priority;
! 327: n->iface_id = rcv_iface_id;
! 328:
! 329: if (n->ifa->cf->bfd)
! 330: ospf_neigh_update_bfd(n, n->ifa->bfd);
! 331: }
! 332:
! 333: u32 n_id = ospf_is_v2(p) ? ipa_to_u32(n->ip) : n->rid;
! 334:
! 335: u32 old_dr = n->dr;
! 336: u32 old_bdr = n->bdr;
! 337: u32 old_priority = n->priority;
! 338: u32 old_iface_id = n->iface_id;
! 339:
! 340: n->dr = rcv_dr;
! 341: n->bdr = rcv_bdr;
! 342: n->priority = rcv_priority;
! 343: n->iface_id = rcv_iface_id;
! 344:
! 345: /* Update inactivity timer */
! 346: ospf_neigh_sm(n, INM_HELLOREC);
! 347:
! 348: /* RFC 2328 9.5.1 - non-eligible routers reply to hello on NBMA nets */
! 349: if (ifa->type == OSPF_IT_NBMA)
! 350: if ((ifa->priority == 0) && (n->priority > 0))
! 351: ospf_send_hello(n->ifa, OHS_HELLO, n);
! 352:
! 353:
! 354: /* Examine list of neighbors */
! 355: for (i = 0; i < neigh_count; i++)
! 356: if (neighbors[i] == htonl(p->router_id))
! 357: goto found_self;
! 358:
! 359: ospf_neigh_sm(n, INM_1WAYREC);
! 360: return;
! 361:
! 362: found_self:
! 363: ospf_neigh_sm(n, INM_2WAYREC);
! 364:
! 365:
! 366: if (n->iface_id != old_iface_id)
! 367: {
! 368: /* If neighbor is DR, also update cached DR interface ID */
! 369: if (ifa->drid == n->rid)
! 370: ifa->dr_iface_id = n->iface_id;
! 371:
! 372: /* RFC 5340 4.4.3 Event 4 - change of neighbor's interface ID */
! 373: ospf_notify_rt_lsa(ifa->oa);
! 374:
! 375: /* Missed in RFC 5340 4.4.3 Event 4 - (Px-)Net-LSA uses iface_id to ref Link-LSAs */
! 376: ospf_notify_net_lsa(ifa);
! 377: }
! 378:
! 379: if (ifa->state == OSPF_IS_WAITING)
! 380: {
! 381: /* Neighbor is declaring itself DR (and there is no BDR) or as BDR */
! 382: if (((n->dr == n_id) && (n->bdr == 0)) || (n->bdr == n_id))
! 383: ospf_iface_sm(ifa, ISM_BACKS);
! 384: }
! 385: else if (ifa->state >= OSPF_IS_DROTHER)
! 386: {
! 387: /* Neighbor changed priority or started/stopped declaring itself as DR/BDR */
! 388: if ((n->priority != old_priority) ||
! 389: ((n->dr == n_id) && (old_dr != n_id)) ||
! 390: ((n->dr != n_id) && (old_dr == n_id)) ||
! 391: ((n->bdr == n_id) && (old_bdr != n_id)) ||
! 392: ((n->bdr != n_id) && (old_bdr == n_id)))
! 393: ospf_iface_sm(ifa, ISM_NEICH);
! 394: }
! 395:
! 396: return;
! 397:
! 398: drop:
! 399: LOG_PKT("Bad HELLO packet from nbr %R on %s - %s (%u)",
! 400: rcv_rid, ifa->ifname, err_dsc, err_val);
! 401: }
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