471 lines
10 KiB
C
471 lines
10 KiB
C
/*
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* BIRD -- OSPF
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*
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* (c) 1999--2004 Ondrej Filip <feela@network.cz>
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*
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* Can be freely distributed and used under the terms of the GNU GPL.
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*/
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#include "ospf.h"
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void
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flush_lsa(struct top_hash_entry *en, struct proto_ospf *po)
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{
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struct proto *p = &po->proto;
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OSPF_TRACE(D_EVENTS,
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"Going to remove node Type: %u, Id: %R, Rt: %R, Age: %u, SN: 0x%x",
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en->lsa.type, en->lsa.id, en->lsa.rt, en->lsa.age, en->lsa.sn);
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s_rem_node(SNODE en);
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if (en->lsa_body != NULL)
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mb_free(en->lsa_body);
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en->lsa_body = NULL;
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ospf_hash_delete(po->gr, en);
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}
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/**
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* ospf_age
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* @po: ospf protocol
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*
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* This function is periodicaly invoked from ospf_disp(). It computes the new
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* age of all LSAs and old (@age is higher than %LSA_MAXAGE) LSAs are flushed
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* whenever possible. If an LSA originated by the router itself is older
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* than %LSREFRESHTIME a new instance is originated.
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*
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* The RFC says that a router should check the checksum of every LSA to detect
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* hardware problems. BIRD does not do this to minimalize CPU utilization.
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*
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* If routing table calculation is scheduled, it also invalidates the old routing
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* table calculation results.
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*/
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void
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ospf_age(struct proto_ospf *po)
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{
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struct proto *p = &po->proto;
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struct top_hash_entry *en, *nxt;
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int flush = can_flush_lsa(po);
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if (po->cleanup) OSPF_TRACE(D_EVENTS, "Running ospf_age cleanup");
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WALK_SLIST_DELSAFE(en, nxt, po->lsal)
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{
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if (po->cleanup)
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{
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en->color = OUTSPF;
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en->dist = LSINFINITY;
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en->nhi = NULL;
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en->nh = IPA_NONE;
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en->lb = IPA_NONE;
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DBG("Infinitying Type: %u, Id: %R, Rt: %R\n", en->lsa.type,
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en->lsa.id, en->lsa.rt);
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}
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if (en->lsa.age == LSA_MAXAGE)
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{
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if (flush)
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flush_lsa(en, po);
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continue;
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}
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if ((en->lsa.rt == p->cf->global->router_id) &&
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(en->lsa.age >= LSREFRESHTIME))
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{
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OSPF_TRACE(D_EVENTS, "Refreshing my LSA: Type: %u, Id: %R, Rt: %R",
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en->lsa.type, en->lsa.id, en->lsa.rt);
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en->lsa.sn++;
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en->lsa.age = 0;
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en->inst_t = now;
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en->ini_age = 0;
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lsasum_calculate(&en->lsa, en->lsa_body);
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ospf_lsupd_flood(po, NULL, NULL, &en->lsa, en->domain, 1);
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continue;
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}
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if ((en->lsa.age = (en->ini_age + (now - en->inst_t))) >= LSA_MAXAGE)
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{
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if (flush)
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{
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flush_lsa(en, po);
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schedule_rtcalc(po);
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}
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else
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en->lsa.age = LSA_MAXAGE;
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}
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}
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po->cleanup = 0;
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}
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void
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htonlsah(struct ospf_lsa_header *h, struct ospf_lsa_header *n)
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{
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n->age = htons(h->age);
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#ifdef OSPFv2
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n->options = h->options;
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#endif
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n->type = htont(h->type);
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n->id = htonl(h->id);
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n->rt = htonl(h->rt);
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n->sn = htonl(h->sn);
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n->checksum = htons(h->checksum);
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n->length = htons(h->length);
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};
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void
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ntohlsah(struct ospf_lsa_header *n, struct ospf_lsa_header *h)
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{
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h->age = ntohs(n->age);
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#ifdef OSPFv2
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h->options = n->options;
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#endif
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h->type = ntoht(n->type);
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h->id = ntohl(n->id);
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h->rt = ntohl(n->rt);
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h->sn = ntohl(n->sn);
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h->checksum = ntohs(n->checksum);
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h->length = ntohs(n->length);
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};
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void
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htonlsab(void *h, void *n, u16 type, u16 len)
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{
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unsigned int i;
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switch (type)
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{
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case LSA_T_RT:
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{
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struct ospf_lsa_rt *hrt, *nrt;
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struct ospf_lsa_rt_link *hrtl, *nrtl;
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u16 links;
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nrt = n;
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hrt = h;
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#ifdef OSPFv2
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links = hrt->links;
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nrt->options = htons(hrt->options);
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nrt->links = htons(hrt->links);
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#else /* OSPFv3 */
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nrt->options = htonl(hrt->options);
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links = (len - sizeof(struct ospf_lsa_rt)) /
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sizeof(struct ospf_lsa_rt_link);
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#endif
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nrtl = (struct ospf_lsa_rt_link *) (nrt + 1);
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hrtl = (struct ospf_lsa_rt_link *) (hrt + 1);
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for (i = 0; i < links; i++)
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{
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#ifdef OSPFv2
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nrtl[i].id = htonl(hrtl[i].id);
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nrtl[i].data = htonl(hrtl[i].data);
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nrtl[i].type = hrtl[i].type;
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nrtl[i].notos = hrtl[i].notos;
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nrtl[i].metric = htons(hrtl[i].metric);
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#else /* OSPFv3 */
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nrtl[i].type = hrtl[i].type;
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nrtl[i].padding = 0;
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nrtl[i].metric = htons(hrtl[i].metric);
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nrtl[i].lif = htonl(hrtl[i].lif);
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nrtl[i].nif = htonl(hrtl[i].nif);
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nrtl[i].id = htonl(hrtl[i].id);
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#endif
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}
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break;
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}
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case LSA_T_NET:
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case LSA_T_SUM_NET:
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case LSA_T_SUM_RT:
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case LSA_T_EXT:
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#ifdef OSPFv3
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case LSA_T_LINK:
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case LSA_T_PREFIX:
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#endif
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{
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u32 *hid, *nid;
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nid = n;
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hid = h;
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for (i = 0; i < (len / sizeof(u32)); i++)
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{
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*(nid + i) = htonl(*(hid + i));
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}
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break;
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}
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default:
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bug("(hton): Unknown LSA");
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}
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};
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void
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ntohlsab(void *n, void *h, u16 type, u16 len)
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{
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unsigned int i;
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switch (type)
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{
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case LSA_T_RT:
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{
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struct ospf_lsa_rt *hrt, *nrt;
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struct ospf_lsa_rt_link *hrtl, *nrtl;
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u16 links;
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nrt = n;
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hrt = h;
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#ifdef OSPFv2
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hrt->options = ntohs(nrt->options);
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links = hrt->links = ntohs(nrt->links);
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#else /* OSPFv3 */
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hrt->options = ntohl(nrt->options);
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links = (len - sizeof(struct ospf_lsa_rt)) /
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sizeof(struct ospf_lsa_rt_link);
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#endif
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nrtl = (struct ospf_lsa_rt_link *) (nrt + 1);
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hrtl = (struct ospf_lsa_rt_link *) (hrt + 1);
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for (i = 0; i < links; i++)
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{
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#ifdef OSPFv2
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hrtl[i].id = ntohl(nrtl[i].id);
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hrtl[i].data = ntohl(nrtl[i].data);
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hrtl[i].type = nrtl[i].type;
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hrtl[i].notos = nrtl[i].notos;
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hrtl[i].metric = ntohs(nrtl[i].metric);
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#else /* OSPFv3 */
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hrtl[i].type = nrtl[i].type;
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hrtl[i].padding = 0;
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hrtl[i].metric = ntohs(nrtl[i].metric);
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hrtl[i].lif = ntohl(nrtl[i].lif);
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hrtl[i].nif = ntohl(nrtl[i].nif);
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hrtl[i].id = ntohl(nrtl[i].id);
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#endif
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}
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break;
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}
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case LSA_T_NET:
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case LSA_T_SUM_NET:
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case LSA_T_SUM_RT:
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case LSA_T_EXT:
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#ifdef OSPFv3
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case LSA_T_LINK:
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case LSA_T_PREFIX:
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#endif
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{
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u32 *hid, *nid;
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hid = h;
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nid = n;
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for (i = 0; i < (len / sizeof(u32)); i++)
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{
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hid[i] = ntohl(nid[i]);
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}
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break;
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}
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default:
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bug("(ntoh): Unknown LSA");
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}
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};
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void
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buf_dump(const char *hdr, const byte *buf, int blen)
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{
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char b2[1024];
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char *bp;
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int first = 1;
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int i;
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const char *lhdr = hdr;
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bp = b2;
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for(i = 0; i < blen; i++)
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{
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if ((i > 0) && ((i % 16) == 0))
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{
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*bp = 0;
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log(L_WARN "%s\t%s", lhdr, b2);
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lhdr = "";
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bp = b2;
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}
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bp += snprintf(bp, 1022, "%02x ", buf[i]);
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}
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*bp = 0;
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log(L_WARN "%s\t%s", lhdr, b2);
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}
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#define MODX 4102 /* larges signed value without overflow */
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/* Fletcher Checksum -- Refer to RFC1008. */
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#define MODX 4102
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#define LSA_CHECKSUM_OFFSET 15
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/* FIXME This is VERY uneficient, I have huge endianity problems */
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void
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lsasum_calculate(struct ospf_lsa_header *h, void *body)
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{
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u16 length = h->length;
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u16 type = h->type;
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// log(L_WARN "Checksum %R %R %d start (len %d)", h->id, h->rt, h->type, length);
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htonlsah(h, h);
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htonlsab(body, body, type, length - sizeof(struct ospf_lsa_header));
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/*
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char buf[1024];
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memcpy(buf, h, sizeof(struct ospf_lsa_header));
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memcpy(buf + sizeof(struct ospf_lsa_header), body, length - sizeof(struct ospf_lsa_header));
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buf_dump("CALC", buf, length);
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*/
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(void) lsasum_check(h, body);
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// log(L_WARN "Checksum result %4x", h->checksum);
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ntohlsah(h, h);
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ntohlsab(body, body, type, length - sizeof(struct ospf_lsa_header));
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}
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/*
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* Note, that this function expects that LSA is in big endianity
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* It also returns value in big endian
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*/
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u16
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lsasum_check(struct ospf_lsa_header *h, void *body)
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{
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u8 *sp, *ep, *p, *q, *b;
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int c0 = 0, c1 = 0;
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int x, y;
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u16 length;
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b = body;
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sp = (char *) h;
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sp += 2; /* Skip Age field */
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length = ntohs(h->length) - 2;
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h->checksum = 0;
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for (ep = sp + length; sp < ep; sp = q)
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{ /* Actually MODX is very large, do we need the for-cyclus? */
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q = sp + MODX;
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if (q > ep)
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q = ep;
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for (p = sp; p < q; p++)
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{
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/*
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* I count with bytes from header and than from body
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* but if there is no body, it's appended to header
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* (probably checksum in update receiving) and I go on
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* after header
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*/
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if ((b == NULL) || (p < (u8 *) (h + 1)))
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{
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c0 += *p;
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}
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else
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{
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c0 += *(b + (p - sp) - sizeof(struct ospf_lsa_header) + 2);
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}
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c1 += c0;
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}
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c0 %= 255;
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c1 %= 255;
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}
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x = ((length - LSA_CHECKSUM_OFFSET) * c0 - c1) % 255;
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if (x <= 0)
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x += 255;
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y = 510 - c0 - x;
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if (y > 255)
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y -= 255;
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((u8 *) & h->checksum)[0] = x;
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((u8 *) & h->checksum)[1] = y;
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return h->checksum;
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}
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int
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lsa_comp(struct ospf_lsa_header *l1, struct ospf_lsa_header *l2)
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/* Return codes from point of view of l1 */
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{
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u32 sn1, sn2;
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sn1 = l1->sn - LSA_INITSEQNO + 1;
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sn2 = l2->sn - LSA_INITSEQNO + 1;
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if (sn1 > sn2)
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return CMP_NEWER;
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if (sn1 < sn2)
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return CMP_OLDER;
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if (l1->checksum != l2->checksum)
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return l1->checksum < l2->checksum ? CMP_OLDER : CMP_NEWER;
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if ((l1->age == LSA_MAXAGE) && (l2->age != LSA_MAXAGE))
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return CMP_NEWER;
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if ((l2->age == LSA_MAXAGE) && (l1->age != LSA_MAXAGE))
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return CMP_OLDER;
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if (ABS(l1->age - l2->age) > LSA_MAXAGEDIFF)
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return l1->age < l2->age ? CMP_NEWER : CMP_OLDER;
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return CMP_SAME;
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}
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/**
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* lsa_install_new - install new LSA into database
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* @po: OSPF protocol
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* @lsa: LSA header
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* @domain: domain of LSA
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* @body: pointer to LSA body
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*
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* This function ensures installing new LSA into LSA database. Old instance is
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* replaced. Several actions are taken to detect if new routing table
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* calculation is necessary. This is described in 13.2 of RFC 2328.
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*/
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struct top_hash_entry *
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lsa_install_new(struct proto_ospf *po, struct ospf_lsa_header *lsa, u32 domain, void *body)
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{
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/* LSA can be temporarrily, but body must be mb_allocated. */
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int change = 0;
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struct top_hash_entry *en;
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if ((en = ospf_hash_find_header(po->gr, domain, lsa)) == NULL)
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{
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en = ospf_hash_get_header(po->gr, domain, lsa);
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change = 1;
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}
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else
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{
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if ((en->lsa.length != lsa->length)
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#ifdef OSPFv2
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|| (en->lsa.options != lsa->options)
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#endif
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|| (en->lsa.age == LSA_MAXAGE)
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|| (lsa->age == LSA_MAXAGE)
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|| memcmp(en->lsa_body, body, lsa->length - sizeof(struct ospf_lsa_header)))
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change = 1;
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s_rem_node(SNODE en);
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}
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DBG("Inst lsa: Id: %R, Rt: %R, Type: %u, Age: %u, Sum: %u, Sn: 0x%x\n",
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lsa->id, lsa->rt, lsa->type, lsa->age, lsa->checksum, lsa->sn);
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s_add_tail(&po->lsal, SNODE en);
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en->inst_t = now;
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if (en->lsa_body != NULL)
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mb_free(en->lsa_body);
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en->lsa_body = body;
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memcpy(&en->lsa, lsa, sizeof(struct ospf_lsa_header));
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en->ini_age = en->lsa.age;
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if (change)
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{
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schedule_rtcalc(po);
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}
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return en;
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}
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