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bird/proto/ospf/packet.c

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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 (%d vs %s)",
ntohs(pkt->length) + OSPF_AUTH_CRYPT_SIZE, size);
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->accfrom > now) || (ptmp->accto < 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 - different area %ld", mesg, sk->faddr, ntohl(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);
log(L_ERR "%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);
log(L_ERR "%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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