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bird/proto/ospf/packet.c
Ondrej Filip 86c84d76b7 Huge OSPF database redesign. Since now, all LSAs of all areas 
are in single database. This avoids duplication of external LSAs and
fixes bug in external LSA distribution.
2004-07-15 16:37:52 +00:00

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/*
* BIRD -- OSPF
*
* (c) 1999--2004 Ondrej Filip <feela@network.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
#include "ospf.h"
#include "nest/password.h"
#include "lib/md5.h"
void
ospf_pkt_fill_hdr(struct ospf_iface *ifa, void *buf, u8 h_type)
{
struct ospf_packet *pkt;
struct proto *p = (struct proto *) (ifa->oa->po);
pkt = (struct ospf_packet *) buf;
pkt->version = OSPF_VERSION;
pkt->type = h_type;
pkt->routerid = htonl(p->cf->global->router_id);
pkt->areaid = htonl(ifa->oa->areaid);
pkt->autype = htons(ifa->autype);
pkt->checksum = 0;
}
unsigned
ospf_pkt_maxsize(struct ospf_iface *ifa)
{
return ifa->iface->mtu - SIZE_OF_IP_HEADER -
((ifa->autype == OSPF_AUTH_CRYPT) ? OSPF_AUTH_CRYPT_SIZE : 0);
}
void
ospf_pkt_finalize(struct ospf_iface *ifa, struct ospf_packet *pkt)
{
struct proto_ospf *po = ifa->oa->po;
struct proto *p = &po->proto;
struct password_item *passwd = password_find (ifa->passwords);
void *tail;
struct MD5Context ctxt;
char password[OSPF_AUTH_CRYPT_SIZE];
pkt->autype = htons(ifa->autype);
switch(ifa->autype)
{
case OSPF_AUTH_SIMPLE:
bzero(&pkt->u, sizeof(union ospf_auth));
if (!passwd)
{
log( L_ERR "No suitable password found for authentication" );
return;
}
password_cpy(pkt->u.password, passwd->password, sizeof(union ospf_auth));
case OSPF_AUTH_NONE:
pkt->checksum = ipsum_calculate(pkt, sizeof(struct ospf_packet) -
sizeof(union ospf_auth), (pkt + 1),
ntohs(pkt->length) -
sizeof(struct ospf_packet), NULL);
break;
case OSPF_AUTH_CRYPT:
if (!passwd)
{
log( L_ERR "No suitable password found for authentication" );
return;
}
pkt->checksum = 0;
if (!ifa->csn)
ifa->csn = (u32) time(NULL);
pkt->u.md5.keyid = passwd->id;
pkt->u.md5.len = OSPF_AUTH_CRYPT_SIZE;
pkt->u.md5.zero = 0;
pkt->u.md5.csn = htonl(ifa->csn++);
tail = ((void *)pkt) + ntohs(pkt->length);
MD5Init(&ctxt);
MD5Update(&ctxt, (char *) pkt, ntohs(pkt->length));
password_cpy(password, passwd->password, OSPF_AUTH_CRYPT_SIZE);
MD5Update(&ctxt, password, OSPF_AUTH_CRYPT_SIZE);
MD5Final(tail, &ctxt);
break;
default:
bug("Unknown authentication type");
}
}
static int
ospf_pkt_checkauth(struct ospf_neighbor *n, struct ospf_iface *ifa, struct ospf_packet *pkt, int size)
{
int i;
struct proto_ospf *po = ifa->oa->po;
struct proto *p = &po->proto;
struct password_item *pass = NULL, *ptmp;
void *tail;
char md5sum[OSPF_AUTH_CRYPT_SIZE];
char password[OSPF_AUTH_CRYPT_SIZE];
struct MD5Context ctxt;
if (pkt->autype != htons(ifa->autype))
{
OSPF_TRACE(D_PACKETS, "OSPF_auth: Method differs (%d)", ntohs(pkt->autype));
return 0;
}
if (n && (ifa != n->ifa))
{
OSPF_TRACE(D_PACKETS, "OSPF_auth: received packet from strange interface (%s/%s)",
ifa->iface->name, n->ifa->iface->name);
return 0;
}
switch(ifa->autype)
{
case OSPF_AUTH_NONE:
return 1;
break;
case OSPF_AUTH_SIMPLE:
pass = password_find (ifa->passwords);
if(!pass)
{
OSPF_TRACE(D_PACKETS, "OSPF_auth: no password found");
return 0;
}
password_cpy(password, pass->password, sizeof(union ospf_auth));
if (memcmp(pkt->u.password, password, sizeof(union ospf_auth)))
{
char ppass[sizeof(union ospf_auth) + 1];
bzero(ppass, (sizeof(union ospf_auth) + 1));
memcpy(ppass, pkt->u.password, sizeof(union ospf_auth));
OSPF_TRACE(D_PACKETS, "OSPF_auth: different passwords (%s)", ppass);
return 0;
}
return 1;
break;
case OSPF_AUTH_CRYPT:
if (pkt->u.md5.len != OSPF_AUTH_CRYPT_SIZE)
{
OSPF_TRACE(D_PACKETS, "OSPF_auth: wrong size of md5 digest");
return 0;
}
if (ntohs(pkt->length) + OSPF_AUTH_CRYPT_SIZE != size)
{
OSPF_TRACE(D_PACKETS, "OSPF_auth: size mismatch");
return 0;
}
if (pkt->u.md5.zero)
{
OSPF_TRACE(D_PACKETS, "OSPF_auth: \"zero\" area is non-zero");
return 0;
}
tail = ((void *)pkt) + ntohs(pkt->length);
WALK_LIST(ptmp, *(ifa->passwords))
{
if (pkt->u.md5.keyid != ptmp->id) continue;
if ((ptmp->genfrom > now) || (ptmp->gento < now)) continue;
pass = ptmp;
break;
}
if(!pass)
{
OSPF_TRACE(D_PACKETS, "OSPF_auth: no suitable md5 password found");
return 0;
}
if(n)
{
if(ntohs(pkt->u.md5.csn) < n->csn)
{
OSPF_TRACE(D_PACKETS, "OSPF_auth: lower sequence number");
return 0;
}
n->csn = ntohs(pkt->u.md5.csn);
}
MD5Init(&ctxt);
MD5Update(&ctxt, (char *) pkt, ntohs(pkt->length));
password_cpy(password, pass->password, OSPF_AUTH_CRYPT_SIZE);
MD5Update(&ctxt, password, OSPF_AUTH_CRYPT_SIZE);
MD5Final(md5sum, &ctxt);
if (memcmp(md5sum, tail, OSPF_AUTH_CRYPT_SIZE))
{
OSPF_TRACE(D_PACKETS, "OSPF_auth: wrong md5 digest");
return 0;
}
return 1;
break;
default:
OSPF_TRACE(D_PACKETS, "OSPF_auth: unknown auth type");
return 0;
}
}
/**
* ospf_rx_hook
* @sk: socket we received the packet. Its ignored.
* @size: size of the packet
*
* This is the entry point for messages from neighbors. Many checks (like
* authentication, checksums, size) are done before the packet is passed to
* non generic functions.
*/
int
ospf_rx_hook(sock * sk, int size)
{
struct ospf_packet *ps;
struct ospf_iface *ifa = (struct ospf_iface *) (sk->data);
struct proto_ospf *po = ifa->oa->po;
struct proto *p = &po->proto;
struct ospf_neighbor *n;
int osize;
char *mesg = "Bad OSPF packet from ";
struct ospf_iface *iff;
if (ifa->stub)
return (1);
ps = (struct ospf_packet *) ipv4_skip_header(sk->rbuf, &size);
if ((ifa->oa->areaid != 0) && (ntohl(ps->areaid) == 0))
{
WALK_LIST(iff, po->iface_list)
{
if ((iff->type == OSPF_IT_VLINK) && (iff->iface == ifa->iface) &&
(iff->voa = ifa->oa) && ipa_equal(sk->faddr, iff->vip))
{
return 1; /* Packet is for VLINK */
}
}
}
DBG("%s: RX_Hook called on interface %s.\n", p->name, sk->iface->name);
osize = ntohs(ps->length);
if (ps == NULL)
{
log(L_ERR "%s%I - bad IP header", mesg, sk->faddr);
return 1;
}
if ((unsigned) size < sizeof(struct ospf_packet))
{
log(L_ERR "%s%I - too short (%u bytes)", mesg, sk->faddr, size);
return 1;
}
if ((osize > size) || (osize != (4 * (osize / 4))))
{
log(L_ERR "%s%I - size field does not match (%d/%d)", mesg, sk->faddr, ntohs(ps->length), size );
return 1;
}
if (ps->version != OSPF_VERSION)
{
log(L_ERR "%s%I - version %u", mesg, sk->faddr, ps->version);
return 1;
}
if ((ps->autype != htons(OSPF_AUTH_CRYPT)) &&
(!ipsum_verify(ps, 16, (void *) ps + sizeof(struct ospf_packet),
ntohs(ps->length) - sizeof(struct ospf_packet), NULL)))
{
log(L_ERR "%s%I - bad checksum", mesg, sk->faddr);
return 1;
}
if (ntohl(ps->areaid) != ifa->oa->areaid)
{
log(L_ERR "%s%I - other area %ld", mesg, sk->faddr, ps->areaid);
return 1;
}
if (ntohl(ps->routerid) == p->cf->global->router_id)
{
log(L_ERR "%s%I - received my own router ID!", mesg, sk->faddr);
return 1;
}
if (ntohl(ps->routerid) == 0)
{
log(L_ERR "%s%I - router id = 0.0.0.0", mesg, sk->faddr);
return 1;
}
if ((unsigned) size > ifa->iface->mtu)
{
log(L_ERR "%s%I - received larger packet than MTU", mesg, sk->faddr);
return 1;
}
n = find_neigh(ifa, ntohl(((struct ospf_packet *) ps)->routerid));
if(!n && (ps->type != HELLO_P))
{
OSPF_TRACE(D_PACKETS, "Received non-hello packet from uknown neighbor (%I)", sk->faddr);
return 1;
}
if (!ospf_pkt_checkauth(n, ifa, ps, size))
{
log(L_ERR "%s%I - authentification failed", mesg, sk->faddr);
return 1;
}
/* Dump packet
pu8=(u8 *)(sk->rbuf+5*4);
for(i=0;i<ntohs(ps->length);i+=4)
DBG("%s: received %u,%u,%u,%u\n",p->name, pu8[i+0], pu8[i+1], pu8[i+2],
pu8[i+3]);
DBG("%s: received size: %u\n",p->name,size);
*/
switch (ps->type)
{
case HELLO_P:
DBG("%s: Hello received.\n", p->name);
ospf_hello_receive((struct ospf_hello_packet *) ps, ifa, n, sk->faddr);
break;
case DBDES_P:
DBG("%s: Database description received.\n", p->name);
ospf_dbdes_receive((struct ospf_dbdes_packet *) ps, ifa, n);
break;
case LSREQ_P:
DBG("%s: Link state request received.\n", p->name);
ospf_lsreq_receive((struct ospf_lsreq_packet *) ps, ifa, n);
break;
case LSUPD_P:
DBG("%s: Link state update received.\n", p->name);
ospf_lsupd_receive((struct ospf_lsupd_packet *) ps, ifa, n);
break;
case LSACK_P:
DBG("%s: Link state ack received.\n", p->name);
ospf_lsack_receive((struct ospf_lsack_packet *) ps, ifa, n);
break;
default:
log(L_ERR "%s%I - wrong type %u", mesg, sk->faddr, ps->type);
return 1;
};
return 1;
}
void
ospf_tx_hook(sock * sk)
{
struct ospf_iface *ifa= (struct ospf_iface *) (sk->data);
struct proto *p = (struct proto *) (ifa->oa->po);
DBG("%s: TX_Hook called on interface %s\n", p->name, sk->iface->name);
}
void
ospf_err_hook(sock * sk, int err UNUSED)
{
struct ospf_iface *ifa= (struct ospf_iface *) (sk->data);
struct proto *p = (struct proto *) (ifa->oa->po);
DBG("%s: Err_Hook called on interface %s\n", p->name, sk->iface->name);
}
void
ospf_send_to_agt(sock * sk, struct ospf_iface *ifa, u8 state)
{
struct ospf_neighbor *n;
WALK_LIST(NODE n, ifa->neigh_list) if (n->state >= state)
ospf_send_to(sk, n->ip, ifa);
}
void
ospf_send_to_bdr(sock * sk, struct ospf_iface *ifa)
{
if (!ipa_equal(ifa->drip, IPA_NONE))
ospf_send_to(sk, ifa->drip, ifa);
if (!ipa_equal(ifa->bdrip, IPA_NONE))
ospf_send_to(sk, ifa->bdrip, ifa);
}
void
ospf_send_to(sock *sk, ip_addr ip, struct ospf_iface *ifa)
{
struct ospf_packet *pkt = (struct ospf_packet *) sk->tbuf;
int len = ntohs(pkt->length) + ((ifa->autype == OSPF_AUTH_CRYPT) ? OSPF_AUTH_CRYPT_SIZE : 0);
ospf_pkt_finalize(ifa, pkt);
if (ipa_equal(ip, IPA_NONE))
sk_send(sk, len);
else
sk_send_to(sk, len, ip, OSPF_PROTO);
}
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