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rde_update.c
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rde_update.c
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/* $OpenBSD$ */
/*
* Copyright (c) 2004 Claudio Jeker <claudio@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/types.h>
#include <sys/queue.h>
#include <sys/hash.h>
#include <stdlib.h>
#include <string.h>
#include "bgpd.h"
#include "rde.h"
in_addr_t up_get_nexthop(struct rde_peer *, struct rde_aspath *);
int up_generate_mp_reach(struct rde_peer *, struct update_attr *,
struct rde_aspath *, u_int8_t);
int up_generate_attr(struct rde_peer *, struct update_attr *,
struct rde_aspath *, u_int8_t);
/* update stuff. */
struct update_prefix {
TAILQ_ENTRY(update_prefix) prefix_l;
RB_ENTRY(update_prefix) entry;
struct uplist_prefix *prefix_h;
struct bgpd_addr prefix;
int prefixlen;
};
struct update_attr {
TAILQ_ENTRY(update_attr) attr_l;
RB_ENTRY(update_attr) entry;
struct uplist_prefix prefix_h;
u_char *attr;
u_char *mpattr;
u_int32_t attr_hash;
u_int16_t attr_len;
u_int16_t mpattr_len;
};
void up_clear(struct uplist_attr *, struct uplist_prefix *);
int up_prefix_cmp(struct update_prefix *, struct update_prefix *);
int up_attr_cmp(struct update_attr *, struct update_attr *);
int up_add(struct rde_peer *, struct update_prefix *, struct update_attr *);
RB_PROTOTYPE(uptree_prefix, update_prefix, entry, up_prefix_cmp)
RB_GENERATE(uptree_prefix, update_prefix, entry, up_prefix_cmp)
RB_PROTOTYPE(uptree_attr, update_attr, entry, up_attr_cmp)
RB_GENERATE(uptree_attr, update_attr, entry, up_attr_cmp)
void
up_init(struct rde_peer *peer)
{
u_int8_t i;
for (i = 0; i < AID_MAX; i++) {
TAILQ_INIT(&peer->updates[i]);
TAILQ_INIT(&peer->withdraws[i]);
}
RB_INIT(&peer->up_prefix);
RB_INIT(&peer->up_attrs);
peer->up_pcnt = 0;
peer->up_acnt = 0;
peer->up_nlricnt = 0;
peer->up_wcnt = 0;
}
void
up_clear(struct uplist_attr *updates, struct uplist_prefix *withdraws)
{
struct update_attr *ua;
struct update_prefix *up;
while ((ua = TAILQ_FIRST(updates)) != NULL) {
TAILQ_REMOVE(updates, ua, attr_l);
while ((up = TAILQ_FIRST(&ua->prefix_h)) != NULL) {
TAILQ_REMOVE(&ua->prefix_h, up, prefix_l);
free(up);
}
free(ua->attr);
free(ua->mpattr);
free(ua);
}
while ((up = TAILQ_FIRST(withdraws)) != NULL) {
TAILQ_REMOVE(withdraws, up, prefix_l);
free(up);
}
}
void
up_down(struct rde_peer *peer)
{
u_int8_t i;
for (i = 0; i < AID_MAX; i++)
up_clear(&peer->updates[i], &peer->withdraws[i]);
RB_INIT(&peer->up_prefix);
RB_INIT(&peer->up_attrs);
peer->up_pcnt = 0;
peer->up_acnt = 0;
peer->up_nlricnt = 0;
peer->up_wcnt = 0;
}
int
up_prefix_cmp(struct update_prefix *a, struct update_prefix *b)
{
int i;
if (a->prefix.aid < b->prefix.aid)
return (-1);
if (a->prefix.aid > b->prefix.aid)
return (1);
switch (a->prefix.aid) {
case AID_INET:
if (ntohl(a->prefix.v4.s_addr) < ntohl(b->prefix.v4.s_addr))
return (-1);
if (ntohl(a->prefix.v4.s_addr) > ntohl(b->prefix.v4.s_addr))
return (1);
break;
case AID_INET6:
i = memcmp(&a->prefix.v6, &b->prefix.v6,
sizeof(struct in6_addr));
if (i > 0)
return (1);
if (i < 0)
return (-1);
break;
case AID_VPN_IPv4:
if (betoh64(a->prefix.vpn4.rd) < betoh64(b->prefix.vpn4.rd))
return (-1);
if (betoh64(a->prefix.vpn4.rd) > betoh64(b->prefix.vpn4.rd))
return (1);
if (ntohl(a->prefix.v4.s_addr) < ntohl(b->prefix.v4.s_addr))
return (-1);
if (ntohl(a->prefix.v4.s_addr) > ntohl(b->prefix.v4.s_addr))
return (1);
if (a->prefixlen < b->prefixlen)
return (-1);
if (a->prefixlen > b->prefixlen)
return (1);
if (a->prefix.vpn4.labellen < b->prefix.vpn4.labellen)
return (-1);
if (a->prefix.vpn4.labellen > b->prefix.vpn4.labellen)
return (1);
return (memcmp(a->prefix.vpn4.labelstack,
b->prefix.vpn4.labelstack, a->prefix.vpn4.labellen));
default:
fatalx("pt_prefix_cmp: unknown af");
}
if (a->prefixlen < b->prefixlen)
return (-1);
if (a->prefixlen > b->prefixlen)
return (1);
return (0);
}
int
up_attr_cmp(struct update_attr *a, struct update_attr *b)
{
int r;
if ((r = a->attr_hash - b->attr_hash) != 0)
return (r);
if ((r = a->attr_len - b->attr_len) != 0)
return (r);
if ((r = a->mpattr_len - b->mpattr_len) != 0)
return (r);
if ((r = memcmp(a->mpattr, b->mpattr, a->mpattr_len)) != 0)
return (r);
return (memcmp(a->attr, b->attr, a->attr_len));
}
int
up_add(struct rde_peer *peer, struct update_prefix *p, struct update_attr *a)
{
struct update_attr *na = NULL;
struct update_prefix *np;
struct uplist_attr *upl = NULL;
struct uplist_prefix *wdl = NULL;
upl = &peer->updates[p->prefix.aid];
wdl = &peer->withdraws[p->prefix.aid];
/* 1. search for attr */
if (a != NULL && (na = RB_FIND(uptree_attr, &peer->up_attrs, a)) ==
NULL) {
/* 1.1 if not found -> add */
TAILQ_INIT(&a->prefix_h);
if (RB_INSERT(uptree_attr, &peer->up_attrs, a) != NULL) {
log_warnx("uptree_attr insert failed");
/* cleanup */
free(a->attr);
free(a->mpattr);
free(a);
free(p);
return (-1);
}
TAILQ_INSERT_TAIL(upl, a, attr_l);
peer->up_acnt++;
} else {
/* 1.2 if found -> use that, free a */
if (a != NULL) {
free(a->attr);
free(a->mpattr);
free(a);
a = na;
/* move to end of update queue */
TAILQ_REMOVE(upl, a, attr_l);
TAILQ_INSERT_TAIL(upl, a, attr_l);
}
}
/* 2. search for prefix */
if ((np = RB_FIND(uptree_prefix, &peer->up_prefix, p)) == NULL) {
/* 2.1 if not found -> add */
if (RB_INSERT(uptree_prefix, &peer->up_prefix, p) != NULL) {
log_warnx("uptree_prefix insert failed");
/*
* cleanup. But do not free a because it is already
* linked or NULL. up_dump_attrnlri() will remove and
* free the empty attribute later.
*/
free(p);
return (-1);
}
peer->up_pcnt++;
} else {
/* 2.2 if found -> use that and free p */
TAILQ_REMOVE(np->prefix_h, np, prefix_l);
free(p);
p = np;
if (p->prefix_h == wdl)
peer->up_wcnt--;
else
peer->up_nlricnt--;
}
/* 3. link prefix to attr */
if (a == NULL) {
TAILQ_INSERT_TAIL(wdl, p, prefix_l);
p->prefix_h = wdl;
peer->up_wcnt++;
} else {
TAILQ_INSERT_TAIL(&a->prefix_h, p, prefix_l);
p->prefix_h = &a->prefix_h;
peer->up_nlricnt++;
}
return (0);
}
int
up_test_update(struct rde_peer *peer, struct prefix *p)
{
struct bgpd_addr addr;
struct attr *attr;
if (peer->state != PEER_UP)
return (-1);
if (p == NULL)
/* no prefix available */
return (0);
if (peer == p->aspath->peer)
/* Do not send routes back to sender */
return (0);
if (p->aspath->flags & F_ATTR_PARSE_ERR)
fatalx("try to send out a botched path");
if (p->aspath->flags & F_ATTR_LOOP)
fatalx("try to send out a looped path");
pt_getaddr(p->prefix, &addr);
if (peer->capa.mp[addr.aid] == 0)
return (-1);
if (p->aspath->peer->conf.ebgp == 0 && peer->conf.ebgp == 0) {
/*
* route reflector redistribution rules:
* 1. if announce is set -> announce
* 2. old non-client, new non-client -> no
* 3. old client, new non-client -> yes
* 4. old non-client, new client -> yes
* 5. old client, new client -> yes
*/
if (p->aspath->peer->conf.reflector_client == 0 &&
peer->conf.reflector_client == 0 &&
(p->aspath->flags & F_PREFIX_ANNOUNCED) == 0)
/* Do not redistribute updates to ibgp peers */
return (0);
}
/* announce type handling */
switch (peer->conf.announce_type) {
case ANNOUNCE_UNDEF:
case ANNOUNCE_NONE:
case ANNOUNCE_DEFAULT_ROUTE:
/*
* no need to withdraw old prefix as this will be
* filtered out as well.
*/
return (-1);
case ANNOUNCE_ALL:
break;
case ANNOUNCE_SELF:
/*
* pass only prefix that have an aspath count
* of zero this is equal to the ^$ regex.
*/
if (p->aspath->aspath->ascnt != 0)
return (0);
break;
}
/* well known communities */
if (community_match(p->aspath,
COMMUNITY_WELLKNOWN, COMMUNITY_NO_ADVERTISE))
return (0);
if (peer->conf.ebgp && community_match(p->aspath,
COMMUNITY_WELLKNOWN, COMMUNITY_NO_EXPORT))
return (0);
if (peer->conf.ebgp && community_match(p->aspath,
COMMUNITY_WELLKNOWN, COMMUNITY_NO_EXPSUBCONFED))
return (0);
/*
* Don't send messages back to originator
* this is not specified in the RFC but seems logical.
*/
if ((attr = attr_optget(p->aspath, ATTR_ORIGINATOR_ID)) != NULL) {
if (memcmp(attr->data, &peer->remote_bgpid,
sizeof(peer->remote_bgpid)) == 0) {
/* would cause loop don't send */
return (-1);
}
}
return (1);
}
int
up_generate(struct rde_peer *peer, struct rde_aspath *asp,
struct bgpd_addr *addr, u_int8_t prefixlen)
{
struct update_attr *ua = NULL;
struct update_prefix *up;
if (asp) {
ua = calloc(1, sizeof(struct update_attr));
if (ua == NULL)
fatal("up_generate");
if (up_generate_attr(peer, ua, asp, addr->aid) == -1) {
log_warnx("generation of bgp path attributes failed");
free(ua);
return (-1);
}
/*
* use aspath_hash as attr_hash, this may be unoptimal
* but currently I don't care.
*/
ua->attr_hash = hash32_buf(ua->attr, ua->attr_len, HASHINIT);
if (ua->mpattr)
ua->attr_hash = hash32_buf(ua->mpattr, ua->mpattr_len,
ua->attr_hash);
}
up = calloc(1, sizeof(struct update_prefix));
if (up == NULL)
fatal("up_generate");
up->prefix = *addr;
up->prefixlen = prefixlen;
if (up_add(peer, up, ua) == -1)
return (-1);
return (0);
}
void
up_generate_updates(struct filter_head *rules, struct rde_peer *peer,
struct prefix *new, struct prefix *old)
{
struct rde_aspath *asp;
struct bgpd_addr addr;
if (peer->state != PEER_UP)
return;
if (new == NULL) {
if (up_test_update(peer, old) != 1)
return;
pt_getaddr(old->prefix, &addr);
if (rde_filter(peer->ribid, NULL, rules, peer, old->aspath,
&addr, old->prefix->prefixlen, old->aspath->peer,
DIR_OUT) == ACTION_DENY)
return;
/* withdraw prefix */
up_generate(peer, NULL, &addr, old->prefix->prefixlen);
} else {
switch (up_test_update(peer, new)) {
case 1:
break;
case 0:
up_generate_updates(rules, peer, NULL, old);
return;
case -1:
return;
}
pt_getaddr(new->prefix, &addr);
if (rde_filter(peer->ribid, &asp, rules, peer, new->aspath,
&addr, new->prefix->prefixlen, new->aspath->peer,
DIR_OUT) == ACTION_DENY) {
path_put(asp);
up_generate_updates(rules, peer, NULL, old);
return;
}
/* generate update */
if (asp != NULL) {
up_generate(peer, asp, &addr, new->prefix->prefixlen);
path_put(asp);
} else
up_generate(peer, new->aspath, &addr,
new->prefix->prefixlen);
}
}
/* send a default route to the specified peer */
void
up_generate_default(struct filter_head *rules, struct rde_peer *peer,
u_int8_t aid)
{
struct rde_aspath *asp, *fasp;
struct bgpd_addr addr;
if (peer->capa.mp[aid] == 0)
return;
asp = path_get();
asp->aspath = aspath_get(NULL, 0);
asp->origin = ORIGIN_IGP;
/* the other default values are OK, nexthop is once again NULL */
/*
* XXX apply default overrides. Not yet possible, mainly a parse.y
* problem.
*/
/* rde_apply_set(asp, set, af, NULL ???, DIR_IN); */
/* filter as usual */
bzero(&addr, sizeof(addr));
addr.aid = aid;
if (rde_filter(peer->ribid, &fasp, rules, peer, asp, &addr, 0, NULL,
DIR_OUT) == ACTION_DENY) {
path_put(fasp);
path_put(asp);
return;
}
/* generate update */
if (fasp != NULL)
up_generate(peer, fasp, &addr, 0);
else
up_generate(peer, asp, &addr, 0);
/* no longer needed */
path_put(fasp);
path_put(asp);
}
/* generate a EoR marker in the update list. This is a horrible hack. */
int
up_generate_marker(struct rde_peer *peer, u_int8_t aid)
{
struct update_attr *ua;
struct update_attr *na = NULL;
struct uplist_attr *upl = NULL;
ua = calloc(1, sizeof(struct update_attr));
if (ua == NULL)
fatal("up_generate_marker");
upl = &peer->updates[aid];
/* 1. search for attr */
if ((na = RB_FIND(uptree_attr, &peer->up_attrs, ua)) == NULL) {
/* 1.1 if not found -> add */
TAILQ_INIT(&ua->prefix_h);
if (RB_INSERT(uptree_attr, &peer->up_attrs, ua) != NULL) {
log_warnx("uptree_attr insert failed");
/* cleanup */
free(ua);
return (-1);
}
TAILQ_INSERT_TAIL(upl, ua, attr_l);
peer->up_acnt++;
} else {
/* 1.2 if found -> use that, free ua */
free(ua);
ua = na;
/* move to end of update queue */
TAILQ_REMOVE(upl, ua, attr_l);
TAILQ_INSERT_TAIL(upl, ua, attr_l);
}
return (0);
}
u_char up_attr_buf[4096];
/* only for IPv4 */
in_addr_t
up_get_nexthop(struct rde_peer *peer, struct rde_aspath *a)
{
in_addr_t mask;
/* nexthop, already network byte order */
if (a->flags & F_NEXTHOP_NOMODIFY) {
/* no modify flag set */
if (a->nexthop == NULL)
return (peer->local_v4_addr.v4.s_addr);
else
return (a->nexthop->exit_nexthop.v4.s_addr);
} else if (a->flags & F_NEXTHOP_SELF)
return (peer->local_v4_addr.v4.s_addr);
else if (!peer->conf.ebgp) {
/*
* If directly connected use peer->local_v4_addr
* this is only true for announced networks.
*/
if (a->nexthop == NULL)
return (peer->local_v4_addr.v4.s_addr);
else if (a->nexthop->exit_nexthop.v4.s_addr ==
peer->remote_addr.v4.s_addr)
/*
* per RFC: if remote peer address is equal to
* the nexthop set the nexthop to our local address.
* This reduces the risk of routing loops.
*/
return (peer->local_v4_addr.v4.s_addr);
else
return (a->nexthop->exit_nexthop.v4.s_addr);
} else if (peer->conf.distance == 1) {
/* ebgp directly connected */
if (a->nexthop != NULL &&
a->nexthop->flags & NEXTHOP_CONNECTED) {
mask = htonl(
prefixlen2mask(a->nexthop->nexthop_netlen));
if ((peer->remote_addr.v4.s_addr & mask) ==
(a->nexthop->nexthop_net.v4.s_addr & mask))
/* nexthop and peer are in the same net */
return (a->nexthop->exit_nexthop.v4.s_addr);
else
return (peer->local_v4_addr.v4.s_addr);
} else
return (peer->local_v4_addr.v4.s_addr);
} else
/* ebgp multihop */
/*
* For ebgp multihop nh->flags should never have
* NEXTHOP_CONNECTED set so it should be possible to unify the
* two ebgp cases. But this is safe and RFC compliant.
*/
return (peer->local_v4_addr.v4.s_addr);
}
int
up_generate_mp_reach(struct rde_peer *peer, struct update_attr *upa,
struct rde_aspath *a, u_int8_t aid)
{
u_int16_t tmp;
switch (aid) {
case AID_INET6:
upa->mpattr_len = 21; /* AFI + SAFI + NH LEN + NH + Reserved */
upa->mpattr = malloc(upa->mpattr_len);
if (upa->mpattr == NULL)
fatal("up_generate_mp_reach");
if (aid2afi(aid, &tmp, &upa->mpattr[2]))
fatalx("up_generate_mp_reachi: bad AID");
tmp = htons(tmp);
memcpy(upa->mpattr, &tmp, sizeof(tmp));
upa->mpattr[3] = sizeof(struct in6_addr);
upa->mpattr[20] = 0; /* Reserved must be 0 */
/* nexthop dance see also up_get_nexthop() */
if (a->flags & F_NEXTHOP_NOMODIFY) {
/* no modify flag set */
if (a->nexthop == NULL)
memcpy(&upa->mpattr[4], &peer->local_v6_addr.v6,
sizeof(struct in6_addr));
else
memcpy(&upa->mpattr[4],
&a->nexthop->exit_nexthop.v6,
sizeof(struct in6_addr));
} else if (a->flags & F_NEXTHOP_SELF)
memcpy(&upa->mpattr[4], &peer->local_v6_addr.v6,
sizeof(struct in6_addr));
else if (!peer->conf.ebgp) {
/* ibgp */
if (a->nexthop == NULL ||
(a->nexthop->exit_nexthop.aid == AID_INET6 &&
!memcmp(&a->nexthop->exit_nexthop.v6,
&peer->remote_addr.v6, sizeof(struct in6_addr))))
memcpy(&upa->mpattr[4], &peer->local_v6_addr.v6,
sizeof(struct in6_addr));
else
memcpy(&upa->mpattr[4],
&a->nexthop->exit_nexthop.v6,
sizeof(struct in6_addr));
} else if (peer->conf.distance == 1) {
/* ebgp directly connected */
if (a->nexthop != NULL &&
a->nexthop->flags & NEXTHOP_CONNECTED)
if (prefix_compare(&peer->remote_addr,
&a->nexthop->nexthop_net,
a->nexthop->nexthop_netlen) == 0) {
/*
* nexthop and peer are in the same
* subnet
*/
memcpy(&upa->mpattr[4],
&a->nexthop->exit_nexthop.v6,
sizeof(struct in6_addr));
return (0);
}
memcpy(&upa->mpattr[4], &peer->local_v6_addr.v6,
sizeof(struct in6_addr));
} else
/* ebgp multihop */
memcpy(&upa->mpattr[4], &peer->local_v6_addr.v6,
sizeof(struct in6_addr));
return (0);
case AID_VPN_IPv4:
upa->mpattr_len = 17; /* AFI + SAFI + NH LEN + NH + Reserved */
upa->mpattr = calloc(upa->mpattr_len, 1);
if (upa->mpattr == NULL)
fatal("up_generate_mp_reach");
if (aid2afi(aid, &tmp, &upa->mpattr[2]))
fatalx("up_generate_mp_reachi: bad AID");
tmp = htons(tmp);
memcpy(upa->mpattr, &tmp, sizeof(tmp));
upa->mpattr[3] = sizeof(u_int64_t) + sizeof(struct in_addr);
/* nexthop dance see also up_get_nexthop() */
if (a->flags & F_NEXTHOP_NOMODIFY) {
/* no modify flag set */
if (a->nexthop == NULL)
memcpy(&upa->mpattr[12],
&peer->local_v4_addr.v4,
sizeof(struct in_addr));
else
/* nexthops are stored as IPv4 addrs */
memcpy(&upa->mpattr[12],
&a->nexthop->exit_nexthop.v4,
sizeof(struct in_addr));
} else if (a->flags & F_NEXTHOP_SELF)
memcpy(&upa->mpattr[12], &peer->local_v4_addr.v4,
sizeof(struct in_addr));
else if (!peer->conf.ebgp) {
/* ibgp */
if (a->nexthop == NULL ||
(a->nexthop->exit_nexthop.aid == AID_INET &&
!memcmp(&a->nexthop->exit_nexthop.v4,
&peer->remote_addr.v4, sizeof(struct in_addr))))
memcpy(&upa->mpattr[12],
&peer->local_v4_addr.v4,
sizeof(struct in_addr));
else
memcpy(&upa->mpattr[12],
&a->nexthop->exit_nexthop.v4,
sizeof(struct in_addr));
} else if (peer->conf.distance == 1) {
/* ebgp directly connected */
if (a->nexthop != NULL &&
a->nexthop->flags & NEXTHOP_CONNECTED)
if (prefix_compare(&peer->remote_addr,
&a->nexthop->nexthop_net,
a->nexthop->nexthop_netlen) == 0) {
/*
* nexthop and peer are in the same
* subnet
*/
memcpy(&upa->mpattr[12],
&a->nexthop->exit_nexthop.v4,
sizeof(struct in_addr));
return (0);
}
memcpy(&upa->mpattr[12], &peer->local_v4_addr.v4,
sizeof(struct in_addr));
} else
/* ebgp multihop */
memcpy(&upa->mpattr[12], &peer->local_v4_addr.v4,
sizeof(struct in_addr));
return (0);
default:
break;
}
return (-1);
}
int
up_generate_attr(struct rde_peer *peer, struct update_attr *upa,
struct rde_aspath *a, u_int8_t aid)
{
struct attr *oa, *newaggr = NULL;
u_char *pdata;
u_int32_t tmp32;
in_addr_t nexthop;
int flags, r, ismp = 0, neednewpath = 0;
u_int16_t len = sizeof(up_attr_buf), wlen = 0, plen;
u_int8_t l;
/* origin */
if ((r = attr_write(up_attr_buf + wlen, len, ATTR_WELL_KNOWN,
ATTR_ORIGIN, &a->origin, 1)) == -1)
return (-1);
wlen += r; len -= r;
/* aspath */
if (!peer->conf.ebgp ||
peer->conf.flags & PEERFLAG_TRANS_AS)
pdata = aspath_prepend(a->aspath, rde_local_as(), 0, &plen);
else
pdata = aspath_prepend(a->aspath, rde_local_as(), 1, &plen);
if (!rde_as4byte(peer))
pdata = aspath_deflate(pdata, &plen, &neednewpath);
if ((r = attr_write(up_attr_buf + wlen, len, ATTR_WELL_KNOWN,
ATTR_ASPATH, pdata, plen)) == -1)
return (-1);
wlen += r; len -= r;
free(pdata);
switch (aid) {
case AID_INET:
nexthop = up_get_nexthop(peer, a);
if ((r = attr_write(up_attr_buf + wlen, len, ATTR_WELL_KNOWN,
ATTR_NEXTHOP, &nexthop, 4)) == -1)
return (-1);
wlen += r; len -= r;
break;
default:
ismp = 1;
break;
}
/*
* The old MED from other peers MUST not be announced to others
* unless the MED is originating from us or the peer is an IBGP one.
* Only exception are routers with "transparent-as yes" set.
*/
if (a->flags & F_ATTR_MED && (peer->conf.ebgp == 0 ||
a->flags & F_ATTR_MED_ANNOUNCE ||
peer->conf.flags & PEERFLAG_TRANS_AS)) {
tmp32 = htonl(a->med);
if ((r = attr_write(up_attr_buf + wlen, len, ATTR_OPTIONAL,
ATTR_MED, &tmp32, 4)) == -1)
return (-1);
wlen += r; len -= r;
}
if (peer->conf.ebgp == 0) {
/* local preference, only valid for ibgp */
tmp32 = htonl(a->lpref);
if ((r = attr_write(up_attr_buf + wlen, len, ATTR_WELL_KNOWN,
ATTR_LOCALPREF, &tmp32, 4)) == -1)
return (-1);
wlen += r; len -= r;
}
/*
* dump all other path attributes. Following rules apply:
* 1. well-known attrs: ATTR_ATOMIC_AGGREGATE and ATTR_AGGREGATOR
* pass unmodified (enforce flags to correct values)
* Actually ATTR_AGGREGATOR may be deflated for OLD 2-byte peers.
* 2. non-transitive attrs: don't re-announce to ebgp peers
* 3. transitive known attrs: announce unmodified
* 4. transitive unknown attrs: set partial bit and re-announce
*/
for (l = 0; l < a->others_len; l++) {
if ((oa = a->others[l]) == NULL)
break;
switch (oa->type) {
case ATTR_ATOMIC_AGGREGATE:
if ((r = attr_write(up_attr_buf + wlen, len,
ATTR_WELL_KNOWN, ATTR_ATOMIC_AGGREGATE,
NULL, 0)) == -1)
return (-1);
break;
case ATTR_AGGREGATOR:
if (!rde_as4byte(peer)) {
/* need to deflate the aggregator */
u_int8_t t[6];
u_int16_t tas;
if ((!(oa->flags & ATTR_TRANSITIVE)) &&
peer->conf.ebgp != 0) {
r = 0;
break;
}
memcpy(&tmp32, oa->data, sizeof(tmp32));
if (ntohl(tmp32) > USHRT_MAX) {
tas = htons(AS_TRANS);
newaggr = oa;
} else
tas = htons(ntohl(tmp32));
memcpy(t, &tas, sizeof(tas));
memcpy(t + sizeof(tas),
oa->data + sizeof(tmp32),
oa->len - sizeof(tmp32));
if ((r = attr_write(up_attr_buf + wlen, len,
oa->flags, oa->type, &t, sizeof(t))) == -1)
return (-1);
break;
}
/* FALLTHROUGH */
case ATTR_COMMUNITIES:
case ATTR_ORIGINATOR_ID:
case ATTR_CLUSTER_LIST:
if ((!(oa->flags & ATTR_TRANSITIVE)) &&
peer->conf.ebgp != 0) {
r = 0;
break;
}
if ((r = attr_write(up_attr_buf + wlen, len,
oa->flags, oa->type, oa->data, oa->len)) == -1)
return (-1);
break;
default:
/* unknown attribute */
if (!(oa->flags & ATTR_TRANSITIVE)) {
/*
* RFC 1771:
* Unrecognized non-transitive optional
* attributes must be quietly ignored and
* not passed along to other BGP peers.
*/
r = 0;
break;
}
if ((r = attr_write(up_attr_buf + wlen, len,
oa->flags | ATTR_PARTIAL, oa->type,
oa->data, oa->len)) == -1)
return (-1);
break;
}
wlen += r; len -= r;
}
/* NEW to OLD conversion when going sending stuff to a 2byte AS peer */
if (neednewpath) {
if (!peer->conf.ebgp ||
peer->conf.flags & PEERFLAG_TRANS_AS)
pdata = aspath_prepend(a->aspath, rde_local_as(), 0,
&plen);
else
pdata = aspath_prepend(a->aspath, rde_local_as(), 1,
&plen);
flags = ATTR_OPTIONAL|ATTR_TRANSITIVE;
if (!(a->flags & F_PREFIX_ANNOUNCED))
flags |= ATTR_PARTIAL;
if (plen == 0)
r = 0;
else if ((r = attr_write(up_attr_buf + wlen, len, flags,
ATTR_AS4_PATH, pdata, plen)) == -1)
return (-1);
wlen += r; len -= r;
free(pdata);
}
if (newaggr) {
flags = ATTR_OPTIONAL|ATTR_TRANSITIVE;
if (!(a->flags & F_PREFIX_ANNOUNCED))
flags |= ATTR_PARTIAL;
if ((r = attr_write(up_attr_buf + wlen, len, flags,
ATTR_AS4_AGGREGATOR, newaggr->data, newaggr->len)) == -1)
return (-1);
wlen += r; len -= r;
}
/* write mp attribute to different buffer */
if (ismp)
if (up_generate_mp_reach(peer, upa, a, aid) == -1)
return (-1);
/* the bgp path attributes are now stored in the global buf */
upa->attr = malloc(wlen);
if (upa->attr == NULL)
fatal("up_generate_attr");
memcpy(upa->attr, up_attr_buf, wlen);
upa->attr_len = wlen;
return (wlen);
}
#define MIN_PREFIX_LEN 5 /* 1 byte prefix length + 4 bytes addr */
int
up_dump_prefix(u_char *buf, int len, struct uplist_prefix *prefix_head,
struct rde_peer *peer)
{
struct update_prefix *upp;
int r, wpos = 0;
u_int8_t i;
while ((upp = TAILQ_FIRST(prefix_head)) != NULL) {
if ((r = prefix_write(buf + wpos, len - wpos,
&upp->prefix, upp->prefixlen)) == -1)
break;
wpos += r;
if (RB_REMOVE(uptree_prefix, &peer->up_prefix, upp) == NULL)
log_warnx("dequeuing update failed.");
TAILQ_REMOVE(upp->prefix_h, upp, prefix_l);
peer->up_pcnt--;
for (i = 0; i < AID_MAX; i++) {
if (upp->prefix_h == &peer->withdraws[i]) {
peer->up_wcnt--;
peer->prefix_sent_withdraw++;
} else {
peer->up_nlricnt--;
peer->prefix_sent_update++;
}
}
free(upp);
}
return (wpos);
}
int
up_dump_attrnlri(u_char *buf, int len, struct rde_peer *peer)
{
struct update_attr *upa;
int r, wpos;
u_int16_t attr_len;
/*
* It is possible that a queued path attribute has no nlri prefix.
* Ignore and remove those path attributes.
*/
while ((upa = TAILQ_FIRST(&peer->updates[AID_INET])) != NULL)
if (TAILQ_EMPTY(&upa->prefix_h)) {
attr_len = upa->attr_len;
if (RB_REMOVE(uptree_attr, &peer->up_attrs,
upa) == NULL)
log_warnx("dequeuing update failed.");
TAILQ_REMOVE(&peer->updates[AID_INET], upa, attr_l);
free(upa->attr);
free(upa->mpattr);
free(upa);
peer->up_acnt--;
/* XXX horrible hack,
* if attr_len is 0, it is a EoR marker */
if (attr_len == 0)
return (-1);
} else
break;
if (upa == NULL || upa->attr_len + MIN_PREFIX_LEN > len) {
/*
* either no packet or not enough space.
* The length field needs to be set to zero else it would be
* an invalid bgp update.
*/
bzero(buf, 2);
return (2);
}
/* first dump the 2-byte path attribute length */
attr_len = htons(upa->attr_len);
memcpy(buf, &attr_len, 2);
wpos = 2;
/* then the path attributes themselves */
memcpy(buf + wpos, upa->attr, upa->attr_len);
wpos += upa->attr_len;
/* last but not least dump the nlri */