mirror of
https://gitlab.nic.cz/labs/bird.git
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383 lines
9.3 KiB
C
383 lines
9.3 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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#include "nest/password.h"
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#include "lib/md5.h"
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void
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ospf_pkt_fill_hdr(struct ospf_iface *ifa, void *buf, u8 h_type)
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{
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struct ospf_packet *pkt;
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struct proto *p;
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p = (struct proto *) (ifa->proto);
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pkt = (struct ospf_packet *) buf;
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pkt->version = OSPF_VERSION;
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pkt->type = h_type;
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pkt->routerid = htonl(p->cf->global->router_id);
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pkt->areaid = htonl(ifa->an);
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pkt->autype = htons(ifa->autype);
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pkt->checksum = 0;
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}
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unsigned
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ospf_pkt_maxsize(struct ospf_iface *ifa)
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{
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return ifa->iface->mtu - SIZE_OF_IP_HEADER -
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((ifa->autype == OSPF_AUTH_CRYPT) ? OSPF_AUTH_CRYPT_SIZE : 0);
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}
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void
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ospf_pkt_finalize(struct ospf_iface *ifa, struct ospf_packet *pkt)
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{
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struct proto_ospf *po = ifa->proto;
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struct proto *p = &po->proto;
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struct password_item *passwd = password_find (ifa->passwords);
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void *tail;
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struct MD5Context ctxt;
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char password[OSPF_AUTH_CRYPT_SIZE];
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pkt->autype = htons(ifa->autype);
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switch(ifa->autype)
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{
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case OSPF_AUTH_NONE:
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case OSPF_AUTH_SIMPLE:
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pkt->checksum = ipsum_calculate(pkt, sizeof(struct ospf_packet) - 8,
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(pkt + 1),
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ntohs(pkt->length) -
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sizeof(struct ospf_packet), NULL);
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password_cpy(pkt->u.password, passwd->password, 8);
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break;
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case OSPF_AUTH_CRYPT:
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if (!passwd)
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{
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log( L_ERR "No suitable password found for authentication" );
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return;
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}
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pkt->checksum = 0;
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if (!ifa->csn)
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ifa->csn = (u32) time(NULL);
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pkt->u.md5.keyid = passwd->id;
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pkt->u.md5.len = OSPF_AUTH_CRYPT_SIZE;
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pkt->u.md5.zero = 0;
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pkt->u.md5.csn = htonl(ifa->csn++);
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tail = ((void *)pkt) + ntohs(pkt->length);
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MD5Init(&ctxt);
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MD5Update(&ctxt, (char *) pkt, ntohs(pkt->length));
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password_cpy(password, passwd->password, OSPF_AUTH_CRYPT_SIZE);
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MD5Update(&ctxt, password, OSPF_AUTH_CRYPT_SIZE);
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MD5Final(tail, &ctxt);
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break;
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default:
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bug("Unknown authentication type");
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}
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}
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static int
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ospf_pkt_checkauth(struct ospf_neighbor *n, struct ospf_packet *pkt, int size)
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{
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int i;
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struct ospf_iface *ifa = n->ifa;
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struct proto_ospf *po = ifa->proto;
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struct proto *p = &po->proto;
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struct password_item *pass = NULL, *ptmp;
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void *tail;
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char md5sum[OSPF_AUTH_CRYPT_SIZE];
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char password[OSPF_AUTH_CRYPT_SIZE];
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struct MD5Context ctxt;
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if (pkt->autype != htons(ifa->autype))
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{
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OSPF_TRACE(D_PACKETS, "OSPF_auth: Method differs (%d)", ntohs(pkt->autype));
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return 0;
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}
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switch(ifa->autype)
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{
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case OSPF_AUTH_NONE:
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return 1;
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break;
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case OSPF_AUTH_SIMPLE:
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pass = password_find (ifa->passwords);
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if(!pass)
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{
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OSPF_TRACE(D_PACKETS, "OSPF_auth: no password found");
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return 0;
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}
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if (memcmp(pkt->u.password,pass, 8))
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{
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OSPF_TRACE(D_PACKETS, "OSPF_auth: different passwords");
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return 0;
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}
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else
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return 1;
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break;
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case OSPF_AUTH_CRYPT:
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if (pkt->u.md5.len != OSPF_AUTH_CRYPT_SIZE)
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{
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OSPF_TRACE(D_PACKETS, "OSPF_auth: wrong size of md5 digest");
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return 0;
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}
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if (ntohs(pkt->length) + OSPF_AUTH_CRYPT_SIZE != size)
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{
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OSPF_TRACE(D_PACKETS, "OSPF_auth: size mismatch");
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return 0;
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}
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if (pkt->u.md5.zero)
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{
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OSPF_TRACE(D_PACKETS, "OSPF_auth: \"zero\" area is non-zero");
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return 0;
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}
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tail = ((void *)pkt) + ntohs(pkt->length);
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WALK_LIST(ptmp, *(ifa->passwords))
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{
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if (pkt->u.md5.keyid != pass->id) continue;
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if ((pass->genfrom > now) || (pass->gento < now)) continue;
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pass = ptmp;
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break;
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}
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if(!pass)
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{
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OSPF_TRACE(D_PACKETS, "OSPF_auth: no suitable md5 password found");
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return 0;
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}
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if(n)
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{
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if(ntohs(pkt->u.md5.csn) <= n->csn)
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{
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OSPF_TRACE(D_PACKETS, "OSPF_auth: lower sequence number");
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return 0;
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}
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n->csn = ntohs(pkt->u.md5.csn);
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}
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MD5Init(&ctxt);
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MD5Update(&ctxt, (char *) pkt, ntohs(pkt->length));
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password_cpy(password, pass->password, OSPF_AUTH_CRYPT_SIZE);
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MD5Update(&ctxt, password, OSPF_AUTH_CRYPT_SIZE);
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MD5Final(md5sum, &ctxt);
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if (!memcmp(md5sum, tail, OSPF_AUTH_CRYPT_SIZE))
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{
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OSPF_TRACE(D_PACKETS, "OSPF_auth: wrong md5 digest");
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return 0;
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}
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return 1;
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break;
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default:
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OSPF_TRACE(D_PACKETS, "OSPF_auth: unknown auth type");
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return 0;
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}
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}
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/**
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* ospf_rx_hook
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* @sk: socket we received the packet. Its ignored.
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* @size: size of the packet
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*
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* This is the entry point for messages from neighbors. Many checks (like
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* authentication, checksums, size) are done before the packet is passed to
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* non generic functions.
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*/
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int
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ospf_rx_hook(sock * sk, int size)
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{
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struct ospf_packet *ps;
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struct ospf_iface *ifa = (struct ospf_iface *) (sk->data);
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struct proto *p = (struct proto *) (ifa->proto);
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struct ospf_neighbor *n;
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int osize;
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char *mesg = "Bad OSPF packet from ";
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if (ifa->stub)
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return (1);
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DBG("%s: RX_Hook called on interface %s.\n", p->name, sk->iface->name);
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ps = (struct ospf_packet *) ipv4_skip_header(sk->rbuf, &size);
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osize = ntohs(ps->length);
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if (ps == NULL)
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{
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log(L_ERR "%s%I - bad IP header", mesg, sk->faddr);
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return 1;
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}
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if ((unsigned) size < sizeof(struct ospf_packet))
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{
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log(L_ERR "%s%I - too short (%u bytes)", mesg, sk->faddr, size);
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return 1;
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}
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if ((osize > size) || (osize != (4 * (osize / 4))))
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{
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log(L_ERR "%s%I - size field does not match (%d/%d)", mesg, sk->faddr, ntohs(ps->length), size );
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return 1;
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}
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if (ps->version != OSPF_VERSION)
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{
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log(L_ERR "%s%I - version %u", mesg, sk->faddr, ps->version);
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return 1;
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}
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if ((ifa->autype != OSPF_AUTH_CRYPT) && (!ipsum_verify(ps, 16, (void *) ps + sizeof(struct ospf_packet),
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ntohs(ps->length) - sizeof(struct ospf_packet), NULL)))
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{
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log(L_ERR "%s%I - bad checksum", mesg, sk->faddr);
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return 1;
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}
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if (ntohl(ps->areaid) != ifa->an)
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{
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log(L_ERR "%s%I - other area %ld", mesg, sk->faddr, ps->areaid);
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return 1;
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}
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if (ntohl(ps->routerid) == p->cf->global->router_id)
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{
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log(L_ERR "%s%I - received my own router ID!", mesg, sk->faddr);
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return 1;
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}
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if (ntohl(ps->routerid) == 0)
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{
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log(L_ERR "%s%I - router id = 0.0.0.0", mesg, sk->faddr);
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return 1;
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}
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if ((unsigned) size > ifa->iface->mtu)
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{
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log(L_ERR "%s%I - received larger packet than MTU", mesg, sk->faddr);
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return 1;
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}
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n = find_neigh(ifa, ntohl(((struct ospf_packet *) ps)->routerid));
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if(!n && (ps->type != HELLO_P))
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{
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OSPF_TRACE(D_PACKETS, "Received non-hello packet from uknown neighbor (%I)", sk->faddr);
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return 1;
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}
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if (!ospf_pkt_checkauth(n, ps, size))
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{
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log(L_ERR "%s%I - authentification failed", mesg, sk->faddr);
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return 1;
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}
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/* Dump packet
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pu8=(u8 *)(sk->rbuf+5*4);
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for(i=0;i<ntohs(ps->length);i+=4)
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DBG("%s: received %u,%u,%u,%u\n",p->name, pu8[i+0], pu8[i+1], pu8[i+2],
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pu8[i+3]);
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DBG("%s: received size: %u\n",p->name,size);
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*/
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switch (ps->type)
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{
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case HELLO_P:
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DBG("%s: Hello received.\n", p->name);
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ospf_hello_receive((struct ospf_hello_packet *) ps, ifa, n, sk->faddr);
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break;
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case DBDES_P:
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DBG("%s: Database description received.\n", p->name);
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ospf_dbdes_receive((struct ospf_dbdes_packet *) ps, ifa, n);
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break;
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case LSREQ_P:
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DBG("%s: Link state request received.\n", p->name);
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ospf_lsreq_receive((struct ospf_lsreq_packet *) ps, ifa, n);
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break;
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case LSUPD_P:
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DBG("%s: Link state update received.\n", p->name);
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ospf_lsupd_receive((struct ospf_lsupd_packet *) ps, ifa, n);
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break;
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case LSACK_P:
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DBG("%s: Link state ack received.\n", p->name);
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ospf_lsack_receive((struct ospf_lsack_packet *) ps, ifa, n);
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break;
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default:
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log(L_ERR "%s%I - wrong type %u", mesg, sk->faddr, ps->type);
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return 1;
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};
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return 1;
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}
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void
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ospf_tx_hook(sock * sk)
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{
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struct ospf_iface *ifa;
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struct proto *p;
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ifa = (struct ospf_iface *) (sk->data);
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p = (struct proto *) (ifa->proto);
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DBG("%s: TX_Hook called on interface %s\n", p->name, sk->iface->name);
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}
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void
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ospf_err_hook(sock * sk, int err UNUSED)
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{
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struct ospf_iface *ifa;
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struct proto *p;
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ifa = (struct ospf_iface *) (sk->data);
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p = (struct proto *) (ifa->proto);
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DBG("%s: Err_Hook called on interface %s\n", p->name, sk->iface->name);
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}
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void
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ospf_send_to_agt(sock * sk, struct ospf_iface *ifa, u8 state)
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{
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struct ospf_neighbor *n;
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WALK_LIST(NODE n, ifa->neigh_list) if (n->state >= state)
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ospf_send_to(sk, n->ip, ifa);
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}
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void
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ospf_send_to_bdr(sock * sk, struct ospf_iface *ifa)
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{
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if (ipa_compare(ifa->drip, ipa_from_u32(0)) != 0)
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ospf_send_to(sk, ifa->drip, ifa);
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if (ipa_compare(ifa->bdrip, ipa_from_u32(0)) != 0)
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ospf_send_to(sk, ifa->bdrip, ifa);
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}
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void
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ospf_send_to(sock *sk, ip_addr ip, struct ospf_iface *ifa)
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{
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struct ospf_packet *pkt = (struct ospf_packet *) sk->tbuf;
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int len = ntohs(pkt->length) + (pkt->autype == OSPF_AUTH_CRYPT) ? OSPF_AUTH_CRYPT_SIZE : 0;
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ospf_pkt_finalize(ifa, pkt);
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if (ipa_equal(ip, IPA_NONE))
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sk_send(sk, len);
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else
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sk_send_to(sk, len, ip, OSPF_PROTO);
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}
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