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mirror of https://gitlab.nic.cz/labs/bird.git synced 2024-11-09 12:48:43 +00:00

BGP: Long-lived graceful restart

The patch implements long-lived graceful restart for BGP, namely
draft-uttaro-idr-bgp-persistence-03.
This commit is contained in:
Ondrej Zajicek (work) 2018-06-04 18:56:05 +02:00
parent 4c0b741ba7
commit c3cff8423e
9 changed files with 274 additions and 15 deletions

View File

@ -213,6 +213,7 @@ struct proto {
int (*rte_better)(struct rte *, struct rte *);
int (*rte_same)(struct rte *, struct rte *);
int (*rte_mergable)(struct rte *, struct rte *);
struct rte * (*rte_modify)(struct rte *, struct linpool *);
void (*rte_insert)(struct network *, struct rte *);
void (*rte_remove)(struct network *, struct rte *);

View File

@ -219,6 +219,7 @@ typedef struct rte {
#ifdef CONFIG_BGP
struct {
u8 suppressed; /* Used for deterministic MED comparison */
s8 stale; /* Route is LLGR_STALE, -1 if unknown */
} bgp;
#endif
#ifdef CONFIG_BABEL
@ -241,6 +242,7 @@ typedef struct rte {
#define REF_FILTERED 2 /* Route is rejected by import filter */
#define REF_STALE 4 /* Route is stale in a refresh cycle */
#define REF_DISCARD 8 /* Route is scheduled for discard */
#define REF_MODIFY 16 /* Route is scheduled for modify */
/* Route is valid for propagation (may depend on other flags in the future), accepts NULL */
static inline int rte_is_valid(rte *r) { return r && !(r->flags & REF_FILTERED); }
@ -279,6 +281,7 @@ int rt_examine(rtable *t, ip_addr prefix, int pxlen, struct proto *p, struct fil
rte *rt_export_merged(struct announce_hook *ah, net *net, rte **rt_free, struct ea_list **tmpa, linpool *pool, int silent);
void rt_refresh_begin(rtable *t, struct announce_hook *ah);
void rt_refresh_end(rtable *t, struct announce_hook *ah);
void rt_modify_stale(rtable *t, struct announce_hook *ah);
void rte_dump(rte *);
void rte_free(rte *);
rte *rte_do_cow(rte *);

View File

@ -1283,6 +1283,28 @@ rte_discard(rte *old) /* Non-filtered route deletion, used during garbage collec
rte_update_unlock();
}
/* Modify existing route by protocol hook, used for long-lived graceful restart */
static inline void
rte_modify(rte *old)
{
rte_update_lock();
rte *new = old->sender->proto->rte_modify(old, rte_update_pool);
if (new != old)
{
if (new)
{
if (!rta_is_cached(new->attrs))
new->attrs = rta_lookup(new->attrs);
new->flags = (old->flags & ~REF_MODIFY) | REF_COW;
}
rte_recalculate(old->sender, old->net, new, old->attrs->src);
}
rte_update_unlock();
}
/* Check rtable for best route to given net whether it would be exported do p */
int
rt_examine(rtable *t, ip_addr prefix, int pxlen, struct proto *p, struct filter *filter)
@ -1373,6 +1395,29 @@ rt_refresh_end(rtable *t, struct announce_hook *ah)
rt_schedule_prune(t);
}
void
rt_modify_stale(rtable *t, struct announce_hook *ah)
{
int prune = 0;
net *n;
rte *e;
FIB_WALK(&t->fib, fn)
{
n = (net *) fn;
for (e = n->routes; e; e = e->next)
if ((e->sender == ah) && (e->flags & REF_STALE) && !(e->flags & REF_FILTERED))
{
e->flags |= REF_MODIFY;
prune = 1;
}
}
FIB_WALK_END;
if (prune)
rt_schedule_prune(t);
}
/**
* rte_dump - dump a route
@ -1592,6 +1637,7 @@ again:
rescan:
for (e=n->routes; e; e=e->next)
{
if (e->sender->proto->flushing || (e->flags & REF_DISCARD))
{
if (*limit <= 0)
@ -1605,6 +1651,22 @@ again:
goto rescan;
}
if (e->flags & REF_MODIFY)
{
if (*limit <= 0)
{
FIB_ITERATE_PUT(fit, fn);
return 0;
}
rte_modify(e);
(*limit)--;
goto rescan;
}
}
if (!n->routes) /* Orphaned FIB entry */
{
FIB_ITERATE_PUT(fit, fn);

View File

@ -1173,6 +1173,9 @@ bgp_community_filter(struct bgp_proto *p, rte *e)
DBG("\tNO_EXPORT\n");
return 1;
}
if (!p->conn->peer_llgr_aware && int_set_contains(d, BGP_COMM_LLGR_STALE))
return 1;
}
return 0;
@ -1233,6 +1236,19 @@ rte_resolvable(rte *rt)
return (rd == RTD_ROUTER) || (rd == RTD_DEVICE) || (rd == RTD_MULTIPATH);
}
static inline int
rte_stale(rte *r)
{
if (r->u.bgp.stale < 0)
{
/* If staleness is unknown, compute and cache it */
eattr *a = ea_find(r->attrs->eattrs, EA_CODE(EAP_BGP, BA_COMMUNITY));
r->u.bgp.stale = a && int_set_contains(a->u.ptr, BGP_COMM_LLGR_STALE);
}
return r->u.bgp.stale;
}
int
bgp_rte_better(rte *new, rte *old)
{
@ -1257,6 +1273,14 @@ bgp_rte_better(rte *new, rte *old)
if (n < o)
return 0;
/* LLGR draft - depreference stale routes */
n = rte_stale(new);
o = rte_stale(old);
if (n > o)
return 0;
if (n < o)
return 1;
/* Start with local preferences */
x = ea_find(new->attrs->eattrs, EA_CODE(EAP_BGP, BA_LOCAL_PREF));
y = ea_find(old->attrs->eattrs, EA_CODE(EAP_BGP, BA_LOCAL_PREF));
@ -1580,6 +1604,27 @@ bgp_rte_recalculate(rtable *table, net *net, rte *new, rte *old, rte *old_best)
return old_is_group_best;
}
struct rte *
bgp_rte_modify_stale(struct rte *r, struct linpool *pool)
{
eattr *a = ea_find(r->attrs->eattrs, EA_CODE(EAP_BGP, BA_COMMUNITY));
struct adata *ad = a ? a->u.ptr : NULL;
if (ad && int_set_contains(ad, BGP_COMM_NO_LLGR))
return NULL;
if (ad && int_set_contains(ad, BGP_COMM_LLGR_STALE))
return r;
r = rte_cow_rta(r, pool);
bgp_attach_attr(&(r->attrs->eattrs), pool, BA_COMMUNITY,
(uintptr_t) int_set_add(pool, ad, BGP_COMM_LLGR_STALE));
r->u.bgp.stale = 1;
return r;
}
static struct adata *
bgp_aggregator_convert_to_new(struct adata *old, struct linpool *pool)
{
@ -1589,7 +1634,6 @@ bgp_aggregator_convert_to_new(struct adata *old, struct linpool *pool)
return newa;
}
/* Take last req_as ASNs from path old2 (in 2B format), convert to 4B format
* and append path old4 (in 4B format).
*/
@ -1985,6 +2029,9 @@ bgp_get_route_info(rte *e, byte *buf, ea_list *attrs)
if (e->u.bgp.suppressed)
buf += bsprintf(buf, "-");
if (rte_stale(e))
buf += bsprintf(buf, "s");
if (e->attrs->hostentry)
{
if (!rte_resolvable(e))

View File

@ -394,10 +394,17 @@ bgp_conn_enter_established_state(struct bgp_conn *conn)
if (p->p.gr_recovery && (p->cf->gr_mode == BGP_GR_ABLE) && peer_gr_ready)
p->p.gr_wait = 1;
if (p->gr_active)
if (p->gr_active == BGP_GRS_ACTIVE)
tm_stop(p->gr_timer);
if (p->gr_active && (!conn->peer_gr_able || !(conn->peer_gr_aflags & BGP_GRF_FORWARDING)))
/* Check F-bit for regular graceful restart */
if ((p->gr_active == BGP_GRS_ACTIVE) &&
(!conn->peer_gr_able || !(conn->peer_gr_aflags & BGP_GRF_FORWARDING)))
bgp_graceful_restart_done(p);
/* Check F-bit for long-lived graceful restart */
if (((p->gr_active == BGP_GRS_LLGR_1) || (p->gr_active == BGP_GRS_LLGR_2)) &&
(!conn->peer_llgr_able || !(conn->peer_llgr_aflags & BGP_LLGRF_FORWARDING)))
bgp_graceful_restart_done(p);
/* GR capability implies that neighbor will send End-of-RIB */
@ -474,11 +481,25 @@ bgp_handle_graceful_restart(struct bgp_proto *p)
p->gr_active ? " - already pending" : "");
proto_notify_state(&p->p, PS_START);
if (p->gr_active)
switch (p->gr_active)
{
case BGP_GRS_ACTIVE:
rt_refresh_end(p->p.main_ahook->table, p->p.main_ahook);
break;
p->gr_active = 1;
bgp_start_timer(p->gr_timer, p->conn->peer_gr_time);
case BGP_GRS_LLGR_1:
rt_refresh_begin(p->p.main_ahook->table, p->p.main_ahook);
return;
case BGP_GRS_LLGR_2:
rt_refresh_begin(p->p.main_ahook->table, p->p.main_ahook);
rt_modify_stale(p->p.main_ahook->table, p->p.main_ahook);
return;
}
p->stale_time = p->cf->llgr_mode ? p->conn->peer_llgr_time : 0;
p->gr_active = !p->stale_time ? BGP_GRS_ACTIVE : BGP_GRS_LLGR_1;
tm_start(p->gr_timer, p->conn->peer_gr_time);
rt_refresh_begin(p->p.main_ahook->table, p->p.main_ahook);
}
@ -515,10 +536,27 @@ bgp_graceful_restart_timeout(timer *t)
{
struct bgp_proto *p = t->data;
BGP_TRACE(D_EVENTS, "Neighbor graceful restart timeout");
bgp_stop(p, 0, NULL, 0);
}
switch (p->gr_active)
{
case BGP_GRS_ACTIVE:
BGP_TRACE(D_EVENTS, "Neighbor graceful restart timeout");
bgp_stop(p, 0, NULL, 0);
return;
case BGP_GRS_LLGR_1:
BGP_TRACE(D_EVENTS, "Neighbor graceful restart timeout");
p->gr_active = BGP_GRS_LLGR_2;
tm_start(p->gr_timer, p->stale_time);
rt_modify_stale(p->p.main_ahook->table, p->p.main_ahook);
return;
case BGP_GRS_LLGR_2:
BGP_TRACE(D_EVENTS, "Long-lived graceful restart timeout");
p->gr_active = 0;
rt_refresh_end(p->p.main_ahook->table, p->p.main_ahook);
return;
}
}
/**
* bgp_refresh_begin - start incoming enhanced route refresh sequence
@ -576,6 +614,10 @@ bgp_send_open(struct bgp_conn *conn)
conn->peer_gr_time = 0;
conn->peer_gr_flags = 0;
conn->peer_gr_aflags = 0;
conn->peer_llgr_aware = 0;
conn->peer_llgr_able = 0;
conn->peer_llgr_time = 0;
conn->peer_llgr_aflags = 0;
conn->peer_ext_messages_support = 0;
DBG("BGP: Sending open\n");
@ -1297,6 +1339,7 @@ bgp_init(struct proto_config *C)
P->rte_better = bgp_rte_better;
P->rte_mergable = bgp_rte_mergable;
P->rte_recalculate = c->deterministic_med ? bgp_rte_recalculate : NULL;
P->rte_modify = bgp_rte_modify_stale;
p->cf = c;
p->local_as = c->local_as;
@ -1332,6 +1375,10 @@ bgp_check_config(struct bgp_config *c)
if (!c->missing_lladdr)
c->missing_lladdr = c->rs_client ? MLL_IGNORE : MLL_SELF;
/* LLGR mode default based on GR mode */
if (c->llgr_mode < 0)
c->llgr_mode = c->gr_mode ? BGP_LLGR_AWARE : 0;
/* Disable after error incompatible with restart limit action */
if (c->c.in_limit && (c->c.in_limit->action == PLA_RESTART) && c->disable_after_error)
c->c.in_limit->action = PLA_DISABLE;
@ -1382,6 +1429,9 @@ bgp_check_config(struct bgp_config *c)
if (c->secondary && !c->c.table->sorted)
cf_error("BGP with secondary option requires sorted table");
if (!c->gr_mode && c->llgr_mode)
cf_error("Long-lived graceful restart requires basic graceful restart");
}
static int
@ -1550,6 +1600,11 @@ bgp_show_proto_info(struct proto *P)
if (p->gr_active)
cli_msg(-1006, " Neighbor graceful restart active");
if (p->gr_active && p->gr_timer->expires)
cli_msg(-1006, " %-15s %d/-",
(p->gr_active != BGP_GRS_LLGR_2) ? "Restart timer:" : "LL stale timer:",
p->gr_timer->expires - now);
if (P->proto_state == PS_START)
{
struct bgp_conn *oc = &p->outgoing_conn;
@ -1563,9 +1618,6 @@ bgp_show_proto_info(struct proto *P)
(oc->connect_retry_timer->expires))
cli_msg(-1006, " Connect delay: %d/%d",
oc->connect_retry_timer->expires - now, p->cf->connect_delay_time);
if (p->gr_active && p->gr_timer->expires)
cli_msg(-1006, " Restart timer: %d/-", p->gr_timer->expires - now);
}
else if (P->proto_state == PS_UP)
{
@ -1574,6 +1626,7 @@ bgp_show_proto_info(struct proto *P)
c->peer_refresh_support ? " refresh" : "",
c->peer_enhanced_refresh_support ? " enhanced-refresh" : "",
c->peer_gr_able ? " restart-able" : (c->peer_gr_aware ? " restart-aware" : ""),
c->peer_llgr_able ? " llgr-able" : (c->peer_llgr_aware ? " llgr-aware" : ""),
c->peer_as4_support ? " AS4" : "",
(c->peer_add_path & ADD_PATH_RX) ? " add-path-rx" : "",
(c->peer_add_path & ADD_PATH_TX) ? " add-path-tx" : "",

View File

@ -52,8 +52,10 @@ struct bgp_config {
int allow_local_as; /* Allow that number of local ASNs in incoming AS_PATHs */
int allow_local_pref; /* Allow LOCAL_PREF in EBGP sessions */
int gr_mode; /* Graceful restart mode (BGP_GR_*) */
int llgr_mode; /* Long-lived graceful restart mode (BGP_LLGR_*) */
int setkey; /* Set MD5 password to system SA/SP database */
unsigned gr_time; /* Graceful restart timeout */
unsigned llgr_time; /* Long-lived graceful restart timeout */
unsigned connect_delay_time; /* Minimum delay between connect attempts */
unsigned connect_retry_time; /* Timeout for connect attempts */
unsigned hold_time, initial_hold_time;
@ -90,6 +92,16 @@ struct bgp_config {
/* For peer_gr_aflags */
#define BGP_GRF_FORWARDING 0x80
#define BGP_LLGR_ABLE 1
#define BGP_LLGR_AWARE 2
#define BGP_LLGRF_FORWARDING 0x80
#define BGP_GRS_NONE 0 /* No GR */
#define BGP_GRS_ACTIVE 1 /* Graceful restart per RFC 4724 */
#define BGP_GRS_LLGR_1 2 /* Long-lived GR phase 1 (restart time) */
#define BGP_GRS_LLGR_2 3 /* Long-lived GR phase 2 (stale time) */
struct bgp_conn {
struct bgp_proto *bgp;
@ -113,6 +125,10 @@ struct bgp_conn {
u16 peer_gr_time;
u8 peer_gr_flags;
u8 peer_gr_aflags;
u8 peer_llgr_aware;
u8 peer_llgr_able;
u16 peer_llgr_time;
u8 peer_llgr_aflags;
u8 peer_ext_messages_support; /* Peer supports extended message length [draft] */
unsigned hold_time, keepalive_time; /* Times calculated from my and neighbor's requirements */
};
@ -133,9 +149,10 @@ struct bgp_proto {
int rr_client; /* Whether neighbor is RR client of me */
int rs_client; /* Whether neighbor is RS client of me */
u8 gr_ready; /* Neighbor could do graceful restart */
u8 gr_active; /* Neighbor is doing graceful restart */
u8 gr_active; /* Neighbor is doing graceful restart (BGP_GRS_*) */
u8 feed_state; /* Feed state (TX) for EoR, RR packets, see BFS_* */
u8 load_state; /* Load state (RX) for EoR, RR packets, see BFS_* */
uint stale_time; /* Long-lived stale time for LLGR */
struct bgp_conn *conn; /* Connection we have established */
struct bgp_conn outgoing_conn; /* Outgoing connection we're working with */
struct bgp_conn incoming_conn; /* Incoming connection we have neither accepted nor rejected yet */
@ -252,6 +269,7 @@ int bgp_get_attr(struct eattr *e, byte *buf, int buflen);
int bgp_rte_better(struct rte *, struct rte *);
int bgp_rte_mergable(rte *pri, rte *sec);
int bgp_rte_recalculate(rtable *table, net *net, rte *new, rte *old, rte *old_best);
struct rte *bgp_rte_modify_stale(struct rte *r, struct linpool *pool);
void bgp_rt_notify(struct proto *P, rtable *tbl UNUSED, net *n, rte *new, rte *old UNUSED, ea_list *attrs);
int bgp_import_control(struct proto *, struct rte **, struct ea_list **, struct linpool *);
void bgp_init_bucket_table(struct bgp_proto *);
@ -398,6 +416,9 @@ void bgp_log_error(struct bgp_proto *p, u8 class, char *msg, unsigned code, unsi
#define BGP_COMM_NO_ADVERTISE 0xffffff02 /* Don't export at all */
#define BGP_COMM_NO_EXPORT_SUBCONFED 0xffffff03 /* NO_EXPORT even in local confederation */
#define BGP_COMM_LLGR_STALE 0xffff0006 /* Route is stale according to LLGR */
#define BGP_COMM_NO_LLGR 0xffff0007 /* Do not treat the route according to LLGR */
/* Origins */
#define ORIGIN_IGP 0

View File

@ -27,7 +27,8 @@ CF_KEYWORDS(BGP, LOCAL, NEIGHBOR, AS, HOLD, TIME, CONNECT, RETRY,
INTERPRET, COMMUNITIES, BGP_ORIGINATOR_ID, BGP_CLUSTER_LIST, IGP,
TABLE, GATEWAY, DIRECT, RECURSIVE, MED, TTL, SECURITY, DETERMINISTIC,
SECONDARY, ALLOW, BFD, ADD, PATHS, RX, TX, GRACEFUL, RESTART, AWARE,
CHECK, LINK, PORT, EXTENDED, MESSAGES, SETKEY, BGP_LARGE_COMMUNITY)
CHECK, LINK, PORT, EXTENDED, MESSAGES, SETKEY, BGP_LARGE_COMMUNITY,
LONG, LIVED, STALE)
CF_KEYWORDS(CEASE, PREFIX, LIMIT, HIT, ADMINISTRATIVE, SHUTDOWN, RESET, PEER,
CONFIGURATION, CHANGE, DECONFIGURED, CONNECTION, REJECTED, COLLISION,
@ -60,6 +61,8 @@ bgp_proto_start: proto_start BGP {
BGP_CFG->default_local_pref = 100;
BGP_CFG->gr_mode = BGP_GR_AWARE;
BGP_CFG->gr_time = 120;
BGP_CFG->llgr_mode = -1;
BGP_CFG->llgr_time = 3600;
BGP_CFG->setkey = 1;
}
;
@ -162,6 +165,9 @@ bgp_proto:
| bgp_proto GRACEFUL RESTART bool ';' { BGP_CFG->gr_mode = $4; }
| bgp_proto GRACEFUL RESTART AWARE ';' { BGP_CFG->gr_mode = BGP_GR_AWARE; }
| bgp_proto GRACEFUL RESTART TIME expr ';' { BGP_CFG->gr_time = $5; }
| bgp_proto LONG LIVED GRACEFUL RESTART bool ';' { BGP_CFG->llgr_mode = $6; }
| bgp_proto LONG LIVED GRACEFUL RESTART AWARE ';' { BGP_CFG->llgr_mode = BGP_LLGR_AWARE; }
| bgp_proto LONG LIVED STALE TIME expr ';' { BGP_CFG->llgr_time = $6; }
| bgp_proto IGP TABLE rtable ';' { BGP_CFG->igp_table = $4; }
| bgp_proto TTL SECURITY bool ';' { BGP_CFG->ttl_security = $4; }
| bgp_proto CHECK LINK bool ';' { BGP_CFG->check_link = $4; }

View File

@ -231,6 +231,32 @@ bgp_put_cap_err(struct bgp_proto *p UNUSED, byte *buf)
return buf;
}
static byte *
bgp_put_cap_llgr1(struct bgp_proto *p, byte *buf)
{
*buf++ = 71; /* Capability 71: Support for long-lived graceful restart */
*buf++ = 7; /* Capability data length */
*buf++ = 0; /* Appropriate AF */
*buf++ = BGP_AF;
*buf++ = 1; /* and SAFI 1 */
/* Next is 8bit flags and 24bit time */
put_u32(buf, p->cf->llgr_time);
buf[0] = p->p.gr_recovery ? BGP_LLGRF_FORWARDING : 0;
buf += 4;
return buf;
}
static byte *
bgp_put_cap_llgr2(struct bgp_proto *p UNUSED, byte *buf)
{
*buf++ = 71; /* Capability 71: Support for long-lived graceful restart */
*buf++ = 0; /* Capability data length */
return buf;
}
static byte *
bgp_create_open(struct bgp_conn *conn, byte *buf)
@ -285,6 +311,11 @@ bgp_create_open(struct bgp_conn *conn, byte *buf)
if (p->cf->enable_extended_messages)
cap = bgp_put_cap_ext_msg(p, cap);
if (p->cf->llgr_mode == BGP_LLGR_ABLE)
cap = bgp_put_cap_llgr1(p, cap);
else if (p->cf->llgr_mode == BGP_LLGR_AWARE)
cap = bgp_put_cap_llgr2(p, cap);
cap_len = cap - buf - 12;
if (cap_len > 0)
{
@ -872,11 +903,38 @@ bgp_parse_capabilities(struct bgp_conn *conn, byte *opt, int len)
conn->peer_enhanced_refresh_support = 1;
break;
case 71: /* Long-lived graceful restart capability, RFC draft */
if (cl % 7)
goto err;
conn->peer_llgr_aware = 1;
conn->peer_llgr_able = 0;
conn->peer_llgr_time = 0;
conn->peer_llgr_aflags = 0;
for (i = 0; i < cl; i += 4)
if (opt[2+i+0] == 0 && opt[2+i+1] == BGP_AF && opt[2+i+2] == 1) /* Match AFI/SAFI */
{
conn->peer_llgr_able = 1;
conn->peer_llgr_time = get_u32(opt + 2+i+3) & 0xffffff;
conn->peer_llgr_aflags = opt[2+i+3];
}
break;
/* We can safely ignore all other capabilities */
}
len -= 2 + cl;
opt += 2 + cl;
}
/* The LLGR capability must be advertised together with the GR capability,
otherwise it must be disregarded */
if (!conn->peer_gr_aware && conn->peer_llgr_aware)
{
conn->peer_llgr_aware = 0;
conn->peer_llgr_able = 0;
conn->peer_llgr_time = 0;
conn->peer_llgr_aflags = 0;
}
return;
err:
@ -1034,7 +1092,8 @@ bgp_rx_open(struct bgp_conn *conn, byte *pkt, uint len)
p->as4_session = p->cf->enable_as4 && conn->peer_as4_support;
p->add_path_rx = (p->cf->add_path & ADD_PATH_RX) && (conn->peer_add_path & ADD_PATH_TX);
p->add_path_tx = (p->cf->add_path & ADD_PATH_TX) && (conn->peer_add_path & ADD_PATH_RX);
p->gr_ready = p->cf->gr_mode && conn->peer_gr_able;
p->gr_ready = (p->cf->gr_mode && conn->peer_gr_able) ||
(p->cf->llgr_mode && conn->peer_llgr_able);
p->ext_messages = p->cf->enable_extended_messages && conn->peer_ext_messages_support;
/* Update RA mode */
@ -1125,6 +1184,7 @@ bgp_rte_update(struct bgp_proto *p, ip_addr prefix, int pxlen,
e->net = n;
e->pflags = 0;
e->u.bgp.suppressed = 0;
e->u.bgp.stale = -1;
rte_update2(p->p.main_ahook, n, e, *src);
}

View File

@ -89,6 +89,12 @@ pipe_rt_notify(struct proto *P, rtable *src_table, net *n, rte *new, rte *old, e
memcpy(&(e->u), &(new->u), sizeof(e->u));
e->pref = new->pref;
e->pflags = new->pflags;
#ifdef CONFIG_BGP
/* Hack to cleanup cached value */
if (e->attrs->src->proto->proto == &proto_bgp)
e->u.bgp.stale = -1;
#endif
}
src = a.src;