mirror of
https://gitlab.nic.cz/labs/bird.git
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468 lines
11 KiB
C
468 lines
11 KiB
C
/*
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* BIRD -- OSPF
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*
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* (c) 1999 - 2000 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 ospf_area *oa)
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{
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struct proto *p=&oa->po->proto;
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OSPF_TRACE(D_EVENTS, "Going to remove node Type: %u, Id: %I, Rt: %I, Age: %u",
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en->lsa.type, en->lsa.id, en->lsa.rt, en->lsa.age);
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s_rem_node(SNODE en);
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ospf_hash_delete(oa->gr,en);
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}
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/**
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* ospf_age
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* @oa: ospf area
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*
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* This function is periodicaly invoked from area_disp(). It computes new
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* age of all LSAs and old (@age is higher than %LSA_MAXAGE) are flushed
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* when ever possible. If some LSA originated by router itself is older
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* than %LSREFRESHTIME new instance is originated.
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*
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* RFC says, that router should check checksum of every LSA to detect some
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* hardware problem. BIRD does not do it to minimalize CPU utilization.
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*
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* If routing table calculation is scheduled, it also invalidates 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 ospf_area *oa)
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{
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struct proto *p=&oa->po->proto;
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struct proto_ospf *po=(struct proto_ospf *)p;
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struct top_hash_entry *en,*nxt;
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int flush=can_flush_lsa(oa);
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OSPF_TRACE(D_EVENTS, "Running ospf_age");
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WALK_SLIST_DELSAFE(en,nxt,oa->lsal)
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{
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if(oa->calcrt)
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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_from_u32(0);
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DBG("Infinitying Type: %u, Id: %I, Rt: %I\n", en->lsa.type, en->lsa.id,
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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) flush_lsa(en,oa);
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continue;
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}
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if((en->lsa.rt==p->cf->global->router_id)&&(en->lsa.age>=LSREFRESHTIME))
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{
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OSPF_TRACE(D_EVENTS, "Refreshing my LSA: Type: %u, Id: %I, Rt: %I",
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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,po);
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flood_lsa(NULL,NULL,&en->lsa,po,NULL,oa,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,oa);
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schedule_rtcalc(oa);
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}
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else en->lsa.age=LSA_MAXAGE;
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}
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}
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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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n->options=h->options;
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n->type=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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h->options=n->options;
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h->type=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, u8 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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links=hrt->links;
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nrt->veb.byte=hrt->veb.byte;
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nrt->padding=0;
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nrt->links=htons(hrt->links);
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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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(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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}
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break;
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}
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case LSA_T_NET:
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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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case LSA_T_SUM_NET:
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case LSA_T_SUM_RT:
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{
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struct ospf_lsa_summ *hs, *ns;
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struct ospf_lsa_summ_net *hn, *nn;
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hs=h;
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ns=n;
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ns->netmask=hs->netmask;
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ipa_hton(ns->netmask);
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hn=(struct ospf_lsa_summ_net *)(hs+1);
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nn=(struct ospf_lsa_summ_net *)(ns+1);
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for(i=0;i<((len-sizeof(struct ospf_lsa_summ))/
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sizeof(struct ospf_lsa_summ_net));i++)
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{
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(nn+i)->tos=(hn+i)->tos;
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(nn+i)->metric=htons((hn+i)->metric);
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(nn+i)->padding=0;
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}
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break;
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}
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case LSA_T_EXT:
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{
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struct ospf_lsa_ext *he, *ne;
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struct ospf_lsa_ext_tos *ht, *nt;
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he=h;
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ne=n;
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ne->netmask=he->netmask;
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ipa_hton(ne->netmask);
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ht=(struct ospf_lsa_ext_tos *)(he+1);
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nt=(struct ospf_lsa_ext_tos *)(ne+1);
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for(i=0;i<((len-sizeof(struct ospf_lsa_ext))/
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sizeof(struct ospf_lsa_ext_tos));i++)
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{
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(nt+i)->etos=(ht+i)->etos;
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(nt+i)->padding=0;
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(nt+i)->metric=htons((ht+i)->metric);
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(nt+i)->fwaddr=(ht+i)->fwaddr;
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ipa_hton((nt+i)->fwaddr);
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(nt+i)->tag=htonl((ht+i)->tag);
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}
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break;
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}
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default: 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, u8 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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hrt->veb.byte=nrt->veb.byte;
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hrt->padding=0;
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links=hrt->links=ntohs(nrt->links);
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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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(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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}
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break;
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}
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case LSA_T_NET:
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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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case LSA_T_SUM_NET:
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case LSA_T_SUM_RT:
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{
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struct ospf_lsa_summ *hs, *ns;
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struct ospf_lsa_summ_net *hn, *nn;
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hs=h;
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ns=n;
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hs->netmask=ns->netmask;
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ipa_ntoh(hs->netmask);
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hn=(struct ospf_lsa_summ_net *)(hs+1);
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nn=(struct ospf_lsa_summ_net *)(ns+1);
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for(i=0;i<((len-sizeof(struct ospf_lsa_summ))/
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sizeof(struct ospf_lsa_summ_net));i++)
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{
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(hn+i)->tos=(nn+i)->tos;
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(hn+i)->metric=ntohs((nn+i)->metric);
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(hn+i)->padding=0;
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}
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break;
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}
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case LSA_T_EXT:
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{
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struct ospf_lsa_ext *he, *ne;
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struct ospf_lsa_ext_tos *ht, *nt;
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he=h;
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ne=n;
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he->netmask=ne->netmask;
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ipa_ntoh(he->netmask);
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ht=(struct ospf_lsa_ext_tos *)(he+1);
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nt=(struct ospf_lsa_ext_tos *)(ne+1);
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for(i=0;i<((len-sizeof(struct ospf_lsa_ext))/
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sizeof(struct ospf_lsa_ext_tos));i++)
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{
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(ht+i)->etos=(nt+i)->etos;
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(ht+i)->padding=0;
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(ht+i)->metric=ntohs((nt+i)->metric);
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(ht+i)->fwaddr=(nt+i)->fwaddr;
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ipa_ntoh((ht+i)->fwaddr);
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(ht+i)->tag=ntohl((nt+i)->tag);
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}
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break;
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}
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default: bug("(ntoh): Unknown LSA");
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}
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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,struct proto_ospf *po)
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{
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u16 length;
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length=h->length;
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htonlsah(h,h);
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htonlsab(body,body,h->type,length-sizeof(struct ospf_lsa_header));
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(void)lsasum_check(h,body,po);
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ntohlsah(h,h);
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ntohlsab(body,body,h->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,struct proto_ospf *po)
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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,chsum;
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b=body;
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sp = (char *) &h->options;
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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) 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) x += 255;
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y = 510 - c0 - x;
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if (y > 255) y -= 255;
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chsum= x + (y << 8);
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h->checksum = chsum;
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return chsum;
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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) return CMP_NEWER;
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if(sn1<sn2) 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)) return CMP_NEWER;
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if((l2->age==LSA_MAXAGE)&&(l1->age!=LSA_MAXAGE)) 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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* @lsa: LSA header
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* @body: pointer to LSA body
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* @oa: current ospf_area
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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 ospf_lsa_header *lsa, void *body, struct ospf_area *oa)
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{
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/* LSA can be temporarrily, but body must be mb_alloced. */
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struct proto *p=&oa->po->proto;
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int change=0;
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unsigned i;
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struct top_hash_entry *en;
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if((en=ospf_hash_find_header(oa->gr,lsa))==NULL)
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{
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en=ospf_hash_get_header(oa->gr,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)||(en->lsa.options!=lsa->options)||
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((en->lsa.age==LSA_MAXAGE)||(lsa->age==LSA_MAXAGE))) change=1;
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else
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{
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u8 *k=en->lsa_body,*l=body;
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for(i=0;i<(lsa->length-sizeof(struct ospf_lsa_header));i++)
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{
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if(*(k+i)!=*(l+i))
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{
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change=1;
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break;
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}
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}
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}
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s_rem_node(SNODE en);
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}
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DBG("Inst lsa: Id: %I, Rt: %I, 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(&oa->lsal, SNODE en);
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en->inst_t=now;
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if(en->lsa_body!=NULL) 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(oa);
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}
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return en;
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}
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