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570 lines
14 KiB
C
570 lines
14 KiB
C
/*
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* BIRD -- OSPF
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*
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* (c) 1999--2005 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 proto_ospf *po = ifa->oa->po;
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struct ospf_packet *pkt;
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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(po->router_id);
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pkt->areaid = htonl(ifa->oa->areaid);
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#ifdef OSPFv3
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pkt->instance_id = ifa->instance_id;
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#endif
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#ifdef OSPFv2
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pkt->autype = htons(ifa->autype);
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#endif
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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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unsigned headers = SIZE_OF_IP_HEADER;
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#ifdef OSPFv2
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if (ifa->autype == OSPF_AUTH_CRYPT)
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headers += OSPF_AUTH_CRYPT_SIZE;
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#endif
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return ifa->tx_length - headers;
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}
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#ifdef OSPFv2
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static 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 password_item *passwd = NULL;
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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->checksum = 0;
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pkt->autype = htons(ifa->autype);
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bzero(&pkt->u, sizeof(union ospf_auth));
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/* Compatibility note: pkt->u may contain anything if autype is
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none, but nonzero values do not work with Mikrotik OSPF */
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switch(ifa->autype)
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{
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case OSPF_AUTH_SIMPLE:
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passwd = password_find(ifa->passwords, 1);
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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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password_cpy(pkt->u.password, passwd->password, sizeof(union ospf_auth));
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case OSPF_AUTH_NONE:
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pkt->checksum = ipsum_calculate(pkt, sizeof(struct ospf_packet) -
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sizeof(union ospf_auth), (pkt + 1),
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ntohs(pkt->length) -
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sizeof(struct ospf_packet), NULL);
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break;
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case OSPF_AUTH_CRYPT:
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passwd = password_find(ifa->passwords, 0);
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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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/* Perhaps use random value to prevent replay attacks after
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reboot when system does not have independent RTC? */
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if (!ifa->csn)
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{
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ifa->csn = (u32) now;
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ifa->csn_use = now;
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}
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/* We must have sufficient delay between sending a packet and increasing
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CSN to prevent reordering of packets (in a network) with different CSNs */
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if ((now - ifa->csn_use) > 1)
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ifa->csn++;
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ifa->csn_use = now;
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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_iface *ifa, struct ospf_packet *pkt, int size)
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{
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struct proto_ospf *po = ifa->oa->po;
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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, 1);
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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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password_cpy(password, pass->password, sizeof(union ospf_auth));
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if (memcmp(pkt->u.password, password, sizeof(union ospf_auth)))
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{
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char ppass[sizeof(union ospf_auth) + 1];
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bzero(ppass, (sizeof(union ospf_auth) + 1));
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memcpy(ppass, pkt->u.password, sizeof(union ospf_auth));
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OSPF_TRACE(D_PACKETS, "OSPF_auth: different passwords (%s)", ppass);
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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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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 (%d vs %d)",
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ntohs(pkt->length) + OSPF_AUTH_CRYPT_SIZE, size);
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return 0;
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}
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tail = ((void *)pkt) + ntohs(pkt->length);
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if (ifa->passwords)
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{
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WALK_LIST(ptmp, *(ifa->passwords))
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{
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if (pkt->u.md5.keyid != ptmp->id) continue;
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if ((ptmp->accfrom > now_real) || (ptmp->accto < now_real)) continue;
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pass = ptmp;
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break;
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}
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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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u32 rcv_csn = ntohl(pkt->u.md5.csn);
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if(rcv_csn < n->csn)
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{
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OSPF_TRACE(D_PACKETS, "OSPF_auth: lower sequence number (rcv %d, old %d)", rcv_csn, n->csn);
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return 0;
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}
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n->csn = rcv_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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#else
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/* OSPFv3 authentication not yet supported */
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static inline void
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ospf_pkt_finalize(struct ospf_iface *ifa, struct ospf_packet *pkt)
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{ }
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static int
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ospf_pkt_checkauth(struct ospf_neighbor *n, struct ospf_iface *ifa, struct ospf_packet *pkt, int size)
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{ return 1; }
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#endif
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/**
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* ospf_rx_hook
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* @sk: socket we received the packet.
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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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char *mesg = "OSPF: Bad packet from ";
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/* We want just packets from sk->iface. Unfortunately, on BSD we
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cannot filter out other packets at kernel level and we receive
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all packets on all sockets */
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if (sk->lifindex != sk->iface->index)
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return 1;
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DBG("OSPF: RX hook called (iface %s, src %I, dst %I)\n",
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sk->ifname, sk->faddr, sk->laddr);
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/* Initially, the packet is associated with the 'master' iface */
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struct ospf_iface *ifa = sk->data;
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struct proto_ospf *po = ifa->oa->po;
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// struct proto *p = &po->proto;
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int src_local, dst_local UNUSED, dst_mcast;
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src_local = ipa_in_net(sk->faddr, ifa->addr->prefix, ifa->addr->pxlen);
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dst_local = ipa_equal(sk->laddr, ifa->addr->ip);
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dst_mcast = ipa_equal(sk->laddr, ifa->all_routers) || ipa_equal(sk->laddr, AllDRouters);
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#ifdef OSPFv2
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/* First, we eliminate packets with strange address combinations.
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* In OSPFv2, they might be for other ospf_ifaces (with different IP
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* prefix) on the same real iface, so we don't log it. We enforce
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* that (src_local || dst_local), therefore we are eliminating all
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* such cases.
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*/
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if (dst_mcast && !src_local)
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return 1;
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if (!dst_mcast && !dst_local)
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return 1;
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/* Ignore my own broadcast packets */
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if (ifa->cf->real_bcast && ipa_equal(sk->faddr, ifa->addr->ip))
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return 1;
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#else /* OSPFv3 */
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/* In OSPFv3, src_local and dst_local mean link-local.
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* RFC 5340 says that local (non-vlink) packets use
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* link-local src address, but does not enforce it. Strange.
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*/
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if (dst_mcast && !src_local)
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log(L_WARN "OSPF: Received multicast packet from %I (not link-local)", sk->faddr);
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#endif
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/* Second, we check packet size, checksum, and the protocol version */
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struct ospf_packet *ps = (struct ospf_packet *) ip_skip_header(sk->rbuf, &size);
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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 (ifa->check_ttl && (sk->rcv_ttl < 255))
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{
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log(L_ERR "%s%I - TTL %d (< 255)", mesg, sk->faddr, sk->rcv_ttl);
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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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uint plen = ntohs(ps->length);
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if ((plen < sizeof(struct ospf_packet)) || ((plen % 4) != 0))
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{
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log(L_ERR "%s%I - invalid length (%u)", mesg, sk->faddr, plen);
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return 1;
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}
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if (sk->flags & SKF_TRUNCATED)
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{
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log(L_WARN "%s%I - too large (%d/%d)", mesg, sk->faddr, plen, size);
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/* If we have dynamic buffers and received truncated message, we expand RX buffer */
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uint bs = plen + 256;
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bs = BIRD_ALIGN(bs, 1024);
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if (!ifa->cf->rx_buffer && (bs > sk->rbsize))
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sk_set_rbsize(sk, bs);
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return 1;
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}
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if (plen > size)
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{
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log(L_ERR "%s%I - size field does not match (%d/%d)", mesg, sk->faddr, plen, 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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#ifdef OSPFv2
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if ((ps->autype != htons(OSPF_AUTH_CRYPT)) &&
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(!ipsum_verify(ps, 16, (void *) ps + sizeof(struct ospf_packet),
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plen - 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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#endif
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/* Third, we resolve associated iface and handle vlinks. */
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u32 areaid = ntohl(ps->areaid);
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u32 rid = ntohl(ps->routerid);
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if ((areaid == ifa->oa->areaid)
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#ifdef OSPFv3
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&& (ps->instance_id == ifa->instance_id)
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#endif
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)
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{
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/* It is real iface, source should be local (in OSPFv2) */
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#ifdef OSPFv2
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if (!src_local)
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return 1;
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#endif
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}
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else if (dst_mcast || (areaid != 0))
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{
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/* Obvious mismatch */
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#ifdef OSPFv2
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/* We ignore mismatch in OSPFv3, because there might be
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other instance with different instance ID */
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log(L_ERR "%s%I - area does not match (%R vs %R)",
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mesg, sk->faddr, areaid, ifa->oa->areaid);
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#endif
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return 1;
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}
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else
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{
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/* Some vlink? */
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struct ospf_iface *iff = NULL;
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WALK_LIST(iff, po->iface_list)
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{
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if ((iff->type == OSPF_IT_VLINK) &&
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(iff->voa == ifa->oa) &&
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#ifdef OSPFv3
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(iff->instance_id == ps->instance_id) &&
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#endif
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(iff->vid == rid))
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{
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/* Vlink should be UP */
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if (iff->state != OSPF_IS_PTP)
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return 1;
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ifa = iff;
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goto found;
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}
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}
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#ifdef OSPFv2
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log(L_WARN "OSPF: Received packet for unknown vlink (ID %R, IP %I)", rid, sk->faddr);
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#endif
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return 1;
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}
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found:
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if (ifa->stub) /* This shouldn't happen */
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return 1;
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if (ipa_equal(sk->laddr, AllDRouters) && (ifa->sk_dr == 0))
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return 1;
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if (rid == po->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 (rid == 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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#ifdef OSPFv2
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/* In OSPFv2, neighbors are identified by either IP or Router ID, base on network type */
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struct ospf_neighbor *n;
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if ((ifa->type == OSPF_IT_BCAST) || (ifa->type == OSPF_IT_NBMA) || (ifa->type == OSPF_IT_PTMP))
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n = find_neigh_by_ip(ifa, sk->faddr);
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else
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n = find_neigh(ifa, rid);
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#else
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struct ospf_neighbor *n = find_neigh(ifa, rid);
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#endif
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if(!n && (ps->type != HELLO_P))
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{
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log(L_WARN "OSPF: Received non-hello packet from unknown neighbor (src %I, iface %s)",
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sk->faddr, ifa->ifname);
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return 1;
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}
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if (!ospf_pkt_checkauth(n, ifa, ps, size))
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{
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log(L_ERR "%s%I - authentication 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(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(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(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(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(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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/*
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void
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ospf_tx_hook(sock * sk)
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{
|
|
struct ospf_iface *ifa= (struct ospf_iface *) (sk->data);
|
|
// struct proto *p = (struct proto *) (ifa->oa->po);
|
|
log(L_ERR "OSPF: TX hook called on %s", ifa->ifname);
|
|
}
|
|
*/
|
|
|
|
void
|
|
ospf_err_hook(sock * sk, int err)
|
|
{
|
|
struct ospf_iface *ifa= (struct ospf_iface *) (sk->data);
|
|
struct proto *p = &(ifa->oa->po->proto);
|
|
log(L_ERR "%s: Socket error on %s: %M", p->name, ifa->ifname, err);
|
|
}
|
|
|
|
void
|
|
ospf_verr_hook(sock *sk, int err)
|
|
{
|
|
struct proto_ospf *po = (struct proto_ospf *) (sk->data);
|
|
struct proto *p = &po->proto;
|
|
log(L_ERR "%s: Vlink socket error: %M", p->name, err);
|
|
}
|
|
|
|
void
|
|
ospf_send_to_agt(struct ospf_iface *ifa, u8 state)
|
|
{
|
|
struct ospf_neighbor *n;
|
|
|
|
WALK_LIST(n, ifa->neigh_list)
|
|
if (n->state >= state)
|
|
ospf_send_to(ifa, n->ip);
|
|
}
|
|
|
|
void
|
|
ospf_send_to_bdr(struct ospf_iface *ifa)
|
|
{
|
|
if (!ipa_equal(ifa->drip, IPA_NONE))
|
|
ospf_send_to(ifa, ifa->drip);
|
|
if (!ipa_equal(ifa->bdrip, IPA_NONE))
|
|
ospf_send_to(ifa, ifa->bdrip);
|
|
}
|
|
|
|
void
|
|
ospf_send_to(struct ospf_iface *ifa, ip_addr dst)
|
|
{
|
|
sock *sk = ifa->sk;
|
|
struct ospf_packet *pkt = (struct ospf_packet *) sk->tbuf;
|
|
int len = ntohs(pkt->length);
|
|
|
|
#ifdef OSPFv2
|
|
if (ifa->autype == OSPF_AUTH_CRYPT)
|
|
len += OSPF_AUTH_CRYPT_SIZE;
|
|
#endif
|
|
|
|
ospf_pkt_finalize(ifa, pkt);
|
|
|
|
int done = sk_send_to(sk, len, dst, 0);
|
|
if (!done)
|
|
log(L_WARN "OSPF: TX queue full on %s", ifa->ifname);
|
|
}
|
|
|