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bird/proto/babel/babel.c

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/*
* BIRD -- The Babel protocol
*
* Copyright (c) 2015--2016 Toke Hoiland-Jorgensen
* (c) 2016--2017 Ondrej Zajicek <santiago@crfreenet.org>
* (c) 2016--2017 CZ.NIC z.s.p.o.
*
* Can be freely distributed and used under the terms of the GNU GPL.
*
* This file contains the main routines for handling and sending TLVs, as
* well as timers and interaction with the nest.
*/
/**
* DOC: The Babel protocol
*
* Babel (RFC6126) is a loop-avoiding distance-vector routing protocol that is
* robust and efficient both in ordinary wired networks and in wireless mesh
* networks.
*
* The Babel protocol keeps state for each neighbour in a &babel_neighbor
* struct, tracking received Hello and I Heard You (IHU) messages. A
* &babel_interface struct keeps hello and update times for each interface, and
* a separate hello seqno is maintained for each interface.
*
* For each prefix, Babel keeps track of both the possible routes (with next hop
* and router IDs), as well as the feasibility distance for each prefix and
* router id. The prefix itself is tracked in a &babel_entry struct, while the
* possible routes for the prefix are tracked as &babel_route entries and the
* feasibility distance is maintained through &babel_source structures.
*
* The main route selection is done in babel_select_route(). This is called when
* an entry is updated by receiving updates from the network or when modified by
* internal timers. The function selects from feasible and reachable routes the
* one with the lowest metric to be announced to the core.
*/
#include <stdlib.h>
#include "babel.h"
#define LOG_PKT_AUTH(msg, args...) \
log_rl(&p->log_pkt_tbf, L_AUTH "%s: " msg, p->p.name, args)
/*
* Is one number greater or equal than another mod 2^16? This is based on the
* definition of serial number space in RFC 1982. Note that arguments are of
* uint type to avoid integer promotion to signed integer.
*/
static inline int ge_mod64k(uint a, uint b)
{ return (u16)(a - b) < 0x8000; }
static void babel_expire_requests(struct babel_proto *p, struct babel_entry *e);
static void babel_select_route(struct babel_proto *p, struct babel_entry *e, struct babel_route *mod);
static inline void babel_announce_retraction(struct babel_proto *p, struct babel_entry *e);
static void babel_send_route_request(struct babel_proto *p, struct babel_entry *e, struct babel_neighbor *n);
static void babel_send_seqno_request(struct babel_proto *p, struct babel_entry *e, struct babel_seqno_request *sr);
static void babel_update_cost(struct babel_neighbor *n);
static inline void babel_kick_timer(struct babel_proto *p);
static inline void babel_iface_kick_timer(struct babel_iface *ifa);
/*
* Functions to maintain data structures
*/
static void
babel_init_entry(struct fib *f UNUSED, void *E)
{
struct babel_entry *e = E;
e->updated = current_time();
init_list(&e->requests);
init_list(&e->sources);
init_list(&e->routes);
}
static inline struct babel_entry *
babel_find_entry(struct babel_proto *p, const net_addr *n)
{
struct fib *rtable = (n->type == NET_IP4) ? &p->ip4_rtable : &p->ip6_rtable;
return fib_find(rtable, n);
}
static struct babel_entry *
babel_get_entry(struct babel_proto *p, const net_addr *n)
{
struct fib *rtable = (n->type == NET_IP4) ? &p->ip4_rtable : &p->ip6_rtable;
struct babel_entry *e = fib_get(rtable, n);
return e;
}
static struct babel_source *
babel_find_source(struct babel_entry *e, u64 router_id)
{
struct babel_source *s;
WALK_LIST(s, e->sources)
if (s->router_id == router_id)
return s;
return NULL;
}
static struct babel_source *
babel_get_source(struct babel_proto *p, struct babel_entry *e, u64 router_id)
{
struct babel_source *s = babel_find_source(e, router_id);
if (s)
return s;
s = sl_allocz(p->source_slab);
s->router_id = router_id;
s->expires = current_time() + BABEL_GARBAGE_INTERVAL;
s->seqno = 0;
s->metric = BABEL_INFINITY;
add_tail(&e->sources, NODE s);
return s;
}
static void
babel_expire_sources(struct babel_proto *p UNUSED, struct babel_entry *e)
{
struct babel_source *n, *nx;
btime now_ = current_time();
WALK_LIST_DELSAFE(n, nx, e->sources)
{
if (n->expires && n->expires <= now_)
{
rem_node(NODE n);
sl_free(n);
}
}
}
static u16
babel_calc_smoothed_metric(struct babel_proto *p, struct babel_route *r, u8 update)
{
struct babel_config *cf = (void *) p->p.cf;
uint metric = r->metric, smoothed_metric = r->smoothed_metric;
btime smoothed_time = r->smoothed_time, now = current_time();
if (!cf->metric_decay || metric == BABEL_INFINITY ||
metric == smoothed_metric || !smoothed_time)
{
smoothed_metric = metric;
smoothed_time = now;
goto out;
}
int diff = metric - smoothed_metric;
/*
* The decay defines the half-life of the metric convergence, so first iterate
* in halving steps
*/
while (smoothed_time < now - cf->metric_decay && diff) {
smoothed_metric += diff/2;
smoothed_time += cf->metric_decay;
diff = metric - smoothed_metric;
}
/*
* Then, update remainder in BABEL_SMOOTHING_STEP intervals using the
* exponential function (approximated via the pre-computed reciprocal).
*/
while (smoothed_time < now - BABEL_SMOOTHING_STEP && diff) {
smoothed_metric += (BABEL_SMOOTHING_STEP * diff *
(cf->smooth_recp - BABEL_SMOOTHING_UNIT) / BABEL_SMOOTHING_UNIT);
smoothed_time += BABEL_SMOOTHING_STEP;
diff = metric - smoothed_metric;
}
/* Consider the metric converged once we're close enough */
if (ABS(diff) < BABEL_SMOOTHING_MIN_DIFF)
smoothed_metric = metric;
out:
if (update) {
r->smoothed_metric = smoothed_metric;
r->smoothed_time = smoothed_time;
}
return smoothed_metric;
}
static u16
babel_update_smoothed_metric(struct babel_proto *p, struct babel_route *r)
{
if (!r->metric)
return 0;
if (!r->smoothed_metric) {
r->smoothed_metric = r->metric;
r->smoothed_time = current_time();
return r->smoothed_metric;
}
u16 smoothed = babel_calc_smoothed_metric(p, r, 1);
DBG("Updated smoothed metric for prefix %N: router-id %lR metric %d/%d\n",
r->e->n.addr, r->router_id, r->metric, smoothed);
return smoothed;
}
static u16
babel_smoothed_metric(struct babel_proto *p, struct babel_route *r)
{
return babel_calc_smoothed_metric(p, r, 0);
}
static void
babel_update_metric(struct babel_proto *p, struct babel_route *r, u16 metric)
{
babel_update_smoothed_metric(p, r);
r->metric = metric;
}
static inline u8
babel_route_better(struct babel_proto *p, struct babel_route *mod,
struct babel_route *best)
{
if (!mod->feasible)
return 0;
if (!best)
return mod->metric < BABEL_INFINITY;
return (mod->metric < best->metric &&
babel_smoothed_metric(p, mod) < babel_smoothed_metric(p, best));
}
static struct babel_route *
babel_find_route(struct babel_entry *e, struct babel_neighbor *n)
{
struct babel_route *r;
WALK_LIST(r, e->routes)
if (r->neigh == n)
return r;
return NULL;
}
static struct babel_route *
babel_get_route(struct babel_proto *p, struct babel_entry *e, struct babel_neighbor *nbr)
{
struct babel_route *r = babel_find_route(e, nbr);
if (r) {
babel_update_smoothed_metric(p, r);
return r;
}
r = sl_allocz(p->route_slab);
r->e = e;
r->neigh = nbr;
add_tail(&e->routes, NODE r);
add_tail(&nbr->routes, NODE &r->neigh_route);
return r;
}
static inline void
babel_retract_route(struct babel_proto *p, struct babel_route *r)
{
r->metric = r->advert_metric = BABEL_INFINITY;
if (r == r->e->selected)
babel_select_route(p, r->e, r);
}
static void
babel_flush_route(struct babel_proto *p UNUSED, struct babel_route *r)
{
DBG("Babel: Flush route %N router_id %lR neigh %I\n",
r->e->n.addr, r->router_id, r->neigh->addr);
rem_node(NODE r);
rem_node(&r->neigh_route);
if (r->e->selected == r)
r->e->selected = NULL;
sl_free(r);
}
static void
babel_expire_route(struct babel_proto *p, struct babel_route *r)
{
struct babel_config *cf = (void *) p->p.cf;
TRACE(D_EVENTS, "Route expiry timer for %N router-id %lR fired",
r->e->n.addr, r->router_id);
if (r->metric < BABEL_INFINITY)
{
r->metric = r->advert_metric = BABEL_INFINITY;
r->expires = current_time() + cf->hold_time;
}
else
{
babel_flush_route(p, r);
}
}
static void
babel_refresh_route(struct babel_proto *p, struct babel_route *r)
{
if (r == r->e->selected)
babel_send_route_request(p, r->e, r->neigh);
r->refresh_time = 0;
}
static void
babel_expire_routes_(struct babel_proto *p, struct fib *rtable)
{
struct babel_config *cf = (void *) p->p.cf;
struct babel_route *r, *rx;
struct fib_iterator fit;
btime now_ = current_time();
FIB_ITERATE_INIT(&fit, rtable);
loop:
FIB_ITERATE_START(rtable, &fit, struct babel_entry, e)
{
int changed = 0;
WALK_LIST_DELSAFE(r, rx, e->routes)
{
if (r->refresh_time && r->refresh_time <= now_)
babel_refresh_route(p, r);
if (r->expires && r->expires <= now_)
{
changed = changed || (r == e->selected);
babel_expire_route(p, r);
}
}
if (changed)
{
/*
* We have to restart the iteration because there may be a cascade of
* synchronous events babel_select_route() -> nest table change ->
* babel_rt_notify() -> rtable change, invalidating hidden variables.
*/
FIB_ITERATE_PUT(&fit);
babel_select_route(p, e, NULL);
goto loop;
}
/* Clean up stale entries */
if ((e->valid == BABEL_ENTRY_STALE) && ((e->updated + cf->hold_time) <= now_))
e->valid = BABEL_ENTRY_DUMMY;
/* Clean up unreachable route */
if (e->unreachable && (!e->valid || (e->router_id == p->router_id)))
{
FIB_ITERATE_PUT(&fit);
babel_announce_retraction(p, e);
goto loop;
}
babel_expire_sources(p, e);
babel_expire_requests(p, e);
/* Remove empty entries */
if (!e->valid && EMPTY_LIST(e->routes) && EMPTY_LIST(e->sources) && EMPTY_LIST(e->requests))
{
FIB_ITERATE_PUT(&fit);
fib_delete(rtable, e);
goto loop;
}
}
FIB_ITERATE_END;
}
static void
babel_expire_routes(struct babel_proto *p)
{
babel_expire_routes_(p, &p->ip4_rtable);
babel_expire_routes_(p, &p->ip6_rtable);
}
static inline int seqno_request_valid(struct babel_seqno_request *sr)
{ return !sr->nbr || sr->nbr->ifa; }
/*
* Add seqno request to the table of pending requests (RFC 6216 3.2.6) and send
* it to network. Do nothing if it is already in the table.
*/
static void
babel_add_seqno_request(struct babel_proto *p, struct babel_entry *e,
u64 router_id, u16 seqno, u8 hop_count,
struct babel_neighbor *nbr)
{
struct babel_seqno_request *sr;
WALK_LIST(sr, e->requests)
if (sr->router_id == router_id && sr->nbr == nbr)
{
/* Found matching or newer */
if (ge_mod64k(sr->seqno, seqno) && seqno_request_valid(sr))
return;
/* Found older */
rem_node(NODE sr);
if (sr->nbr)
rem_node(&sr->nbr_node);
goto found;
}
/* No entries found */
sr = sl_allocz(p->seqno_slab);
found:
sr->router_id = router_id;
sr->seqno = seqno;
sr->hop_count = hop_count;
sr->count = 0;
sr->expires = current_time() + BABEL_SEQNO_REQUEST_EXPIRY;
if (sr->nbr = nbr)
add_tail(&nbr->requests, &sr->nbr_node);
add_tail(&e->requests, NODE sr);
babel_send_seqno_request(p, e, sr);
}
static void
babel_remove_seqno_request(struct babel_proto *p UNUSED, struct babel_seqno_request *sr)
{
if (sr->nbr)
rem_node(&sr->nbr_node);
rem_node(NODE sr);
sl_free(sr);
}
static int
babel_satisfy_seqno_request(struct babel_proto *p, struct babel_entry *e,
u64 router_id, u16 seqno)
{
struct babel_seqno_request *sr, *srx;
int ret = 0;
WALK_LIST_DELSAFE(sr, srx, e->requests)
if ((sr->router_id == router_id) && ge_mod64k(seqno, sr->seqno))
{
/* Found a matching request, remove it; there may be multiple outstanding
* requests, so continue looping
*/
babel_remove_seqno_request(p, sr);
ret = 1;
}
return ret;
}
static void
babel_expire_requests(struct babel_proto *p, struct babel_entry *e)
{
struct babel_seqno_request *sr, *srx;
btime now_ = current_time();
WALK_LIST_DELSAFE(sr, srx, e->requests)
{
/* Remove seqno requests sent to dead neighbors */
if (!seqno_request_valid(sr))
{
babel_remove_seqno_request(p, sr);
continue;
}
/* Handle expired requests - resend or remove */
if (sr->expires && sr->expires <= now_)
{
if (sr->count < BABEL_SEQNO_REQUEST_RETRY)
{
sr->count++;
sr->expires += (BABEL_SEQNO_REQUEST_EXPIRY << sr->count);
babel_send_seqno_request(p, e, sr);
}
else
{
TRACE(D_EVENTS, "Seqno request for %N router-id %lR expired",
e->n.addr, sr->router_id);
babel_remove_seqno_request(p, sr);
continue;
}
}
}
}
static struct babel_neighbor *
babel_find_neighbor(struct babel_iface *ifa, ip_addr addr)
{
struct babel_neighbor *nbr;
WALK_LIST(nbr, ifa->neigh_list)
if (ipa_equal(nbr->addr, addr))
return nbr;
return NULL;
}
static struct babel_neighbor *
babel_get_neighbor(struct babel_iface *ifa, ip_addr addr)
{
struct babel_proto *p = ifa->proto;
struct babel_neighbor *nbr = babel_find_neighbor(ifa, addr);
if (nbr)
return nbr;
TRACE(D_EVENTS, "New neighbor %I on %s", addr, ifa->iface->name);
nbr = mb_allocz(ifa->pool, sizeof(struct babel_neighbor));
nbr->ifa = ifa;
nbr->addr = addr;
nbr->rxcost = BABEL_INFINITY;
nbr->txcost = BABEL_INFINITY;
nbr->cost = BABEL_INFINITY;
nbr->init_expiry = current_time() + BABEL_INITIAL_NEIGHBOR_TIMEOUT;
init_list(&nbr->routes);
init_list(&nbr->requests);
add_tail(&ifa->neigh_list, NODE nbr);
nbr->srtt_pool = mb_allocz(ifa->pool, ifa->cf->rtt_win_len*sizeof(btime));
nbr->srtt_pool_sorted = mb_allocz(ifa->pool, ifa->cf->rtt_win_len*sizeof(btime));
nbr->srtt_poll_idx = nbr->srtt_pool_len = 0;
return nbr;
}
static void
babel_flush_neighbor(struct babel_proto *p, struct babel_neighbor *nbr)
{
struct babel_route *r;
node *n;
TRACE(D_EVENTS, "Removing neighbor %I on %s", nbr->addr, nbr->ifa->iface->name);
WALK_LIST_FIRST(n, nbr->routes)
{
r = SKIP_BACK(struct babel_route, neigh_route, n);
babel_retract_route(p, r);
babel_flush_route(p, r);
}
struct babel_seqno_request *sr;
WALK_LIST_FIRST2(sr, nbr_node, nbr->requests)
babel_remove_seqno_request(p, sr);
nbr->ifa = NULL;
rem_node(NODE nbr);
mb_free(nbr->srtt_pool);
mb_free(nbr->srtt_pool_sorted);
mb_free(nbr);
}
static void
babel_expire_ihu(struct babel_proto *p, struct babel_neighbor *nbr)
{
TRACE(D_EVENTS, "IHU from nbr %I on %s expired", nbr->addr, nbr->ifa->iface->name);
nbr->txcost = BABEL_INFINITY;
nbr->ihu_expiry = 0;
babel_update_cost(nbr);
}
static void
babel_expire_hello(struct babel_proto *p, struct babel_neighbor *nbr, btime now_)
{
again:
nbr->hello_map <<= 1;
if (nbr->hello_cnt < 16)
nbr->hello_cnt++;
nbr->hello_expiry += nbr->last_hello_int;
/* We may expire multiple hellos if last_hello_int is too short */
if (nbr->hello_map && nbr->hello_expiry <= now_)
goto again;
TRACE(D_EVENTS, "Hello from nbr %I on %s expired, %d left",
nbr->addr, nbr->ifa->iface->name, u32_popcount(nbr->hello_map));
if (nbr->hello_map)
babel_update_cost(nbr);
else
babel_flush_neighbor(p, nbr);
}
static void
babel_expire_neighbors(struct babel_proto *p)
{
struct babel_iface *ifa;
struct babel_neighbor *nbr, *nbx;
btime now_ = current_time();
WALK_LIST(ifa, p->interfaces)
{
WALK_LIST_DELSAFE(nbr, nbx, ifa->neigh_list)
{
if (nbr->ihu_expiry && nbr->ihu_expiry <= now_)
babel_expire_ihu(p, nbr);
if (nbr->init_expiry && nbr->init_expiry <= now_)
{ babel_flush_neighbor(p, nbr); continue; }
if (nbr->hello_expiry && nbr->hello_expiry <= now_)
{ babel_expire_hello(p, nbr, now_); continue; }
}
}
}
/*
* Best route selection
*/
/*
* From the RFC (section 3.5.1):
*
* a route advertisement carrying the quintuple (prefix, plen, router-id, seqno,
* metric) is feasible if one of the following conditions holds:
*
* - metric is infinite; or
*
* - no entry exists in the source table indexed by (id, prefix, plen); or
*
* - an entry (prefix, plen, router-id, seqno', metric') exists in the source
* table, and either
* - seqno' < seqno or
* - seqno = seqno' and metric < metric'.
*/
static inline int
babel_is_feasible(struct babel_source *s, u16 seqno, u16 metric)
{
return !s ||
(metric == BABEL_INFINITY) ||
(seqno > s->seqno) ||
((seqno == s->seqno) && (metric < s->metric));
}
/* Simple additive metric - Appendix 3.1 in the RFC */
static inline u16
babel_compute_metric(struct babel_neighbor *n, uint metric)
{
return MIN(metric + n->cost, BABEL_INFINITY);
}
static void
babel_update_cost(struct babel_neighbor *nbr)
{
struct babel_proto *p = nbr->ifa->proto;
struct babel_iface_config *cf = nbr->ifa->cf;
uint rcv = u32_popcount(nbr->hello_map); // number of bits set
uint max = nbr->hello_cnt;
uint rxcost = BABEL_INFINITY; /* Cost to announce in IHU */
uint txcost = BABEL_INFINITY; /* Effective cost for route selection */
if (!rcv || !nbr->ifa->up)
goto done;
switch (cf->type)
{
case BABEL_IFACE_TYPE_WIRED:
case BABEL_IFACE_TYPE_TUNNEL:
/* k-out-of-j selection - Appendix 2.1 in the RFC. */
/* Link is bad if less than cf->limit/16 of expected hellos were received */
if (rcv * 16 < cf->limit * max)
break;
rxcost = cf->rxcost;
txcost = nbr->txcost;
break;
case BABEL_IFACE_TYPE_WIRELESS:
/*
* ETX - Appendix 2.2 in the RFC.
*
* alpha = prob. of successful transmission estimated by the neighbor
* beta = prob. of successful transmission estimated by the router
* rxcost = nominal rxcost of the router / beta
* txcost = nominal rxcost of the neighbor / (alpha * beta)
* = received txcost / beta
*
* Note that received txcost is just neighbor's rxcost. Beta is rcv/max,
* we use inverse values of beta (i.e. max/rcv) to stay in integers.
*/
rxcost = MIN( cf->rxcost * max / rcv, BABEL_INFINITY);
txcost = MIN(nbr->txcost * max / rcv, BABEL_INFINITY);
break;
}
if (cf->rtt_cost && nbr->srtt > cf->rtt_min)
{
uint rtt_cost = cf->rtt_cost;
if (nbr->srtt < cf->rtt_max)
{
uint rtt_interval = cf->rtt_max TO_US - cf->rtt_min TO_US;
uint rtt_diff = (nbr->srtt TO_US - cf->rtt_min TO_US);
rtt_cost = (rtt_cost * rtt_diff) / rtt_interval;
}
txcost = MIN(txcost + rtt_cost, BABEL_INFINITY);
rxcost = MIN(rxcost + rtt_cost, BABEL_INFINITY);
TRACE(D_EVENTS, "Added RTT cost %u to nbr %I on %s with srtt %u.%03u ms",
rtt_cost, nbr->addr, nbr->ifa->iface->name, nbr->srtt/1000, nbr->srtt%1000);
}
done:
/* If RX cost changed, send IHU with next Hello */
if (rxcost != nbr->rxcost)
{
nbr->rxcost = rxcost;
nbr->ihu_cnt = 0;
}
/* If link cost changed, run route selection */
if (txcost != nbr->cost)
{
TRACE(D_EVENTS, "Cost of nbr %I on %s changed from %u to %u",
nbr->addr, nbr->ifa->iface->name, nbr->cost, txcost);
nbr->cost = txcost;
struct babel_route *r; node *n;
WALK_LIST2(r, n, nbr->routes, neigh_route)
{
babel_update_metric(p, r, babel_compute_metric(nbr, r->advert_metric));
babel_select_route(p, r->e, r);
}
}
}
/**
* babel_announce_rte - announce selected route to the core
* @p: Babel protocol instance
* @e: Babel route entry to announce
*
* This function announces a Babel entry to the core if it has a selected
* incoming path, and retracts it otherwise. If there is no selected route but
* the entry is valid and ours, the unreachable route is announced instead.
*/
static void
babel_announce_rte(struct babel_proto *p, struct babel_entry *e)
{
struct babel_route *r = e->selected;
struct channel *c = (e->n.addr->type == NET_IP4) ? p->ip4_channel : p->ip6_channel;
if (r)
{
rta a0 = {
.source = RTS_BABEL,
.scope = SCOPE_UNIVERSE,
.dest = RTD_UNICAST,
.pref = c->preference,
.from = r->neigh->addr,
.nh.gw = r->next_hop,
.nh.iface = r->neigh->ifa->iface,
.eattrs = alloca(sizeof(ea_list) + 3*sizeof(eattr)),
};
*a0.eattrs = (ea_list) { .count = 3 };
a0.eattrs->attrs[0] = (eattr) {
.id = EA_BABEL_METRIC,
.type = EAF_TYPE_INT,
.u.data = r->metric,
};
struct adata *ad = alloca(sizeof(struct adata) + sizeof(u64));
ad->length = sizeof(u64);
memcpy(ad->data, &(r->router_id), sizeof(u64));
a0.eattrs->attrs[1] = (eattr) {
.id = EA_BABEL_ROUTER_ID,
.type = EAF_TYPE_OPAQUE,
.u.ptr = ad,
};
a0.eattrs->attrs[2] = (eattr) {
.id = EA_BABEL_SEQNO,
.type = EAF_TYPE_INT,
.u.data = r->seqno,
};
/*
* If we cannot find a reachable neighbour, set the entry to be onlink. This
* makes it possible to, e.g., assign /32 addresses on a mesh interface and
* have routing work.
*/
if (!neigh_find(&p->p, r->next_hop, r->neigh->ifa->iface, 0))
a0.nh.flags = RNF_ONLINK;
rta *a = rta_lookup(&a0);
rte *rte = rte_get_temp(a, p->p.main_source);
e->unreachable = 0;
rte_update2(c, e->n.addr, rte, p->p.main_source);
}
else if (e->valid && (e->router_id != p->router_id))
{
/* Unreachable */
rta a0 = {
.source = RTS_BABEL,
.scope = SCOPE_UNIVERSE,
.dest = RTD_UNREACHABLE,
.pref = 1,
};
rta *a = rta_lookup(&a0);
rte *rte = rte_get_temp(a, p->p.main_source);
rte->pflags = 0;
e->unreachable = 1;
rte_update2(c, e->n.addr, rte, p->p.main_source);
}
else
{
/* Retraction */
e->unreachable = 0;
rte_update2(c, e->n.addr, NULL, p->p.main_source);
}
}
/* Special case of babel_announce_rte() just for retraction */
static inline void
babel_announce_retraction(struct babel_proto *p, struct babel_entry *e)
{
struct channel *c = (e->n.addr->type == NET_IP4) ? p->ip4_channel : p->ip6_channel;
e->unreachable = 0;
rte_update2(c, e->n.addr, NULL, p->p.main_source);
}
/**
* babel_select_route - select best route for given route entry
* @p: Babel protocol instance
* @e: Babel entry to select the best route for
* @mod: Babel route that was modified or NULL if unspecified
*
* Select the best reachable and feasible route for a given prefix among the
* routes received from peers, and propagate it to the nest. This just selects
* the reachable and feasible route with the lowest metric, but keeps selected
* the old one in case of tie.
*
* If no feasible route is available for a prefix that previously had a route
* selected, a seqno request is sent to try to get a valid route. If the entry
* is valid and not owned by us, the unreachable route is announced to the nest
* (to blackhole packets going to it, as per section 2.8). It is later removed
* by babel_expire_routes(). Otherwise, the route is just removed from the nest.
*
* Argument @mod is used to optimize best route calculation. When specified, the
* function can assume that only the @mod route was modified to avoid full best
* route selection and announcement when non-best route was modified in minor
* way. The caller is advised to not call babel_select_route() when no change is
* done (e.g. periodic route updates) to avoid unnecessary announcements of the
* same best route. The caller is not required to call the function in case of a
* retraction of a non-best route.
*
* Note that the function does not active triggered updates. That is done by
* babel_rt_notify() when the change is propagated back to Babel.
*/
static void
babel_select_route(struct babel_proto *p, struct babel_entry *e, struct babel_route *mod)
{
struct babel_route *r, *best = e->selected;
/* Shortcut if only non-best was modified */
if (mod && (mod != best))
{
if (babel_route_better(p, mod, best))
best = mod;
else
return;
}
else
{
/* Selected route may be modified and no longer admissible */
if (!best || (best->metric == BABEL_INFINITY) || !best->feasible)
best = NULL;
/* best will be compared to many routes below, make sure it's up-to-date */
if (best)
babel_update_smoothed_metric(p, best);
/* Find the best feasible route from all routes */
WALK_LIST(r, e->routes)
if (babel_route_better(p, r, best))
best = r;
}
if (best)
{
if (best != e->selected)
{
u16 smoothed = babel_update_smoothed_metric(p, best);
TRACE(D_EVENTS, "Picked new route for prefix %N: router-id %lR metric %d/%d",
e->n.addr, best->router_id, best->metric, smoothed);
}
}
else if (e->selected)
{
/*
* We have lost all feasible routes. We have to broadcast seqno request
* (Section 3.8.2.1) and keep unreachable route for a while (section 2.8).
* The later is done automatically by babel_announce_rte().
*/
TRACE(D_EVENTS, "Lost feasible route for prefix %N", e->n.addr);
if (e->valid && (e->selected->router_id == e->router_id))
babel_add_seqno_request(p, e, e->selected->router_id, e->selected->seqno + 1, 0, NULL);
}
else
return;
e->selected = best;
babel_announce_rte(p, e);
}
/*
* Functions to send replies
*/
static void
babel_send_ack(struct babel_iface *ifa, ip_addr dest, u16 nonce)
{
struct babel_proto *p = ifa->proto;
union babel_msg msg = {};
TRACE(D_PACKETS, "Sending ACK to %I with nonce %d", dest, nonce);
msg.type = BABEL_TLV_ACK;
msg.ack.nonce = nonce;
babel_send_unicast(&msg, ifa, dest);
}
static void
babel_build_ihu(union babel_msg *msg, struct babel_iface *ifa, struct babel_neighbor *n)
{
struct babel_proto *p = ifa->proto;
msg->type = BABEL_TLV_IHU;
msg->ihu.addr = n->addr;
msg->ihu.rxcost = n->rxcost;
msg->ihu.interval = ifa->cf->ihu_interval;
if (n->last_tstamp_rcvd && ifa->cf->rtt_send)
{
msg->ihu.tstamp = n->last_tstamp;
msg->ihu.tstamp_rcvd = n->last_tstamp_rcvd TO_US;
}
TRACE(D_PACKETS, "Sending IHU for %I with rxcost %d interval %t",
msg->ihu.addr, msg->ihu.rxcost, (btime) msg->ihu.interval);
}
static void
babel_send_ihu(struct babel_iface *ifa, struct babel_neighbor *n)
{
union babel_msg msg = {};
babel_build_ihu(&msg, ifa, n);
babel_send_unicast(&msg, ifa, n->addr);
n->ihu_cnt = BABEL_IHU_INTERVAL_FACTOR;
}
static void
babel_send_ihus(struct babel_iface *ifa)
{
struct babel_neighbor *n;
WALK_LIST(n, ifa->neigh_list)
{
if (n->hello_cnt && (--n->ihu_cnt <= 0))
{
union babel_msg msg = {};
babel_build_ihu(&msg, ifa, n);
babel_enqueue(&msg, ifa);
n->ihu_cnt = BABEL_IHU_INTERVAL_FACTOR;
}
}
}
static void
babel_send_hello(struct babel_iface *ifa, uint interval)
{
struct babel_proto *p = ifa->proto;
union babel_msg msg = {};
msg.type = BABEL_TLV_HELLO;
msg.hello.seqno = ifa->hello_seqno++;
msg.hello.interval = interval ?: ifa->cf->hello_interval;
if (ifa->cf->rtt_send)
msg.hello.tstamp = 1; /* real timestamp will be set on TLV write */
TRACE(D_PACKETS, "Sending hello on %s with seqno %d interval %t",
ifa->ifname, msg.hello.seqno, (btime) msg.hello.interval);
babel_enqueue(&msg, ifa);
babel_send_ihus(ifa);
}
static void
babel_send_route_request(struct babel_proto *p, struct babel_entry *e, struct babel_neighbor *n)
{
union babel_msg msg = {};
TRACE(D_PACKETS, "Sending route request for %N to %I", e->n.addr, n->addr);
msg.type = BABEL_TLV_ROUTE_REQUEST;
net_copy(&msg.route_request.net, e->n.addr);
babel_send_unicast(&msg, n->ifa, n->addr);
}
static void
babel_send_wildcard_request(struct babel_iface *ifa)
{
struct babel_proto *p = ifa->proto;
union babel_msg msg = {};
TRACE(D_PACKETS, "Sending wildcard route request on %s", ifa->ifname);
msg.type = BABEL_TLV_ROUTE_REQUEST;
msg.route_request.full = 1;
babel_enqueue(&msg, ifa);
}
static void
babel_send_seqno_request(struct babel_proto *p, struct babel_entry *e, struct babel_seqno_request *sr)
{
union babel_msg msg = {};
msg.type = BABEL_TLV_SEQNO_REQUEST;
msg.seqno_request.hop_count = sr->hop_count ?: BABEL_INITIAL_HOP_COUNT;
msg.seqno_request.seqno = sr->seqno;
msg.seqno_request.router_id = sr->router_id;
net_copy(&msg.seqno_request.net, e->n.addr);
if (sr->nbr)
{
TRACE(D_PACKETS, "Sending seqno request for %N router-id %lR seqno %d to %I on %s",
e->n.addr, sr->router_id, sr->seqno, sr->nbr->addr, sr->nbr->ifa->ifname);
babel_send_unicast(&msg, sr->nbr->ifa, sr->nbr->addr);
}
else
{
TRACE(D_PACKETS, "Sending broadcast seqno request for %N router-id %lR seqno %d",
e->n.addr, sr->router_id, sr->seqno);
struct babel_iface *ifa;
WALK_LIST(ifa, p->interfaces)
babel_enqueue(&msg, ifa);
}
}
/**
* babel_send_update - send route table updates
* @ifa: Interface to transmit on
* @changed: Only send entries changed since this time
*
* This function produces update TLVs for all entries changed since the time
* indicated by the &changed parameter and queues them for transmission on the
* selected interface. During the process, the feasibility distance for each
* transmitted entry is updated.
*/
static void
babel_send_update_(struct babel_iface *ifa, btime changed, struct fib *rtable)
{
struct babel_proto *p = ifa->proto;
/* Update increase was requested */
if (p->update_seqno_inc)
{
p->update_seqno++;
p->update_seqno_inc = 0;
}
FIB_WALK(rtable, struct babel_entry, e)
{
if (!e->valid)
continue;
/* Our own seqno might have changed, in which case we update the routes we
originate. */
if ((e->router_id == p->router_id) && (e->seqno < p->update_seqno))
{
e->seqno = p->update_seqno;
e->updated = current_time();
}
/* Skip routes that weren't updated since 'changed' time */
if (e->updated < changed)
continue;
TRACE(D_PACKETS, "Sending update for %N router-id %lR seqno %d metric %d",
e->n.addr, e->router_id, e->seqno, e->metric);
union babel_msg msg = {};
msg.type = BABEL_TLV_UPDATE;
msg.update.interval = ifa->cf->update_interval;
msg.update.seqno = e->seqno;
msg.update.metric = e->metric;
msg.update.router_id = e->router_id;
net_copy(&msg.update.net, e->n.addr);
msg.update.next_hop = ((e->n.addr->type == NET_IP4) ?
ifa->next_hop_ip4 : ifa->next_hop_ip6);
/* Do not send route if next hop is unknown, e.g. no configured IPv4 address */
if (ipa_zero(msg.update.next_hop))
continue;
babel_enqueue(&msg, ifa);
/* Update feasibility distance for redistributed routes */
if (e->router_id != p->router_id)
{
struct babel_source *s = babel_get_source(p, e, e->router_id);
s->expires = current_time() + BABEL_GARBAGE_INTERVAL;
if ((msg.update.seqno > s->seqno) ||
((msg.update.seqno == s->seqno) && (msg.update.metric < s->metric)))
{
s->seqno = msg.update.seqno;
s->metric = msg.update.metric;
}
}
}
FIB_WALK_END;
}
static void
babel_send_update(struct babel_iface *ifa, btime changed)
{
struct babel_proto *p = ifa->proto;
babel_send_update_(ifa, changed, &p->ip4_rtable);
babel_send_update_(ifa, changed, &p->ip6_rtable);
}
static void
babel_trigger_iface_update(struct babel_iface *ifa)
{
struct babel_proto *p = ifa->proto;
/* Interface not active or already scheduled */
if (!ifa->up || ifa->want_triggered)
return;
TRACE(D_EVENTS, "Scheduling triggered updates for %s seqno %d",
ifa->iface->name, p->update_seqno);
ifa->want_triggered = current_time();
babel_iface_kick_timer(ifa);
}
/* Sends and update on all interfaces. */
static void
babel_trigger_update(struct babel_proto *p)
{
if (p->triggered)
return;
struct babel_iface *ifa;
WALK_LIST(ifa, p->interfaces)
babel_trigger_iface_update(ifa);
p->triggered = 1;
}
/* A retraction is an update with an infinite metric */
static void
babel_send_retraction(struct babel_iface *ifa, net_addr *n)
{
struct babel_proto *p = ifa->proto;
union babel_msg msg = {};
TRACE(D_PACKETS, "Sending retraction for %N seqno %d", n, p->update_seqno);
msg.type = BABEL_TLV_UPDATE;
msg.update.interval = ifa->cf->update_interval;
msg.update.seqno = p->update_seqno;
msg.update.metric = BABEL_INFINITY;
msg.update.net = *n;
babel_enqueue(&msg, ifa);
}
static void
babel_send_wildcard_retraction(struct babel_iface *ifa)
{
struct babel_proto *p = ifa->proto;
union babel_msg msg = {};
TRACE(D_PACKETS, "Sending wildcard retraction on %s", ifa->ifname);
msg.type = BABEL_TLV_UPDATE;
msg.update.wildcard = 1;
msg.update.interval = ifa->cf->update_interval;
msg.update.seqno = p->update_seqno;
msg.update.metric = BABEL_INFINITY;
babel_enqueue(&msg, ifa);
}
/*
* TLV handler helpers
*/
/* Update hello history according to Appendix A1 of the RFC */
static void
babel_update_hello_history(struct babel_neighbor *n, u16 seqno, uint interval)
{
/*
* Compute the difference between expected and received seqno (modulo 2^16).
* If the expected and received seqnos are within 16 of each other, the modular
* difference is going to be less than 16 for one of the directions. Otherwise,
* the values differ too much, so just reset the state.
*/
u16 delta = ((uint) seqno - (uint) n->next_hello_seqno);
if ((delta == 0) || (n->hello_cnt == 0))
{
/* Do nothing */
}
else if (delta <= 16)
{
/* Sending node decreased interval; fast-forward */
n->hello_map <<= delta;
n->hello_cnt = MIN(n->hello_cnt + delta, 16);
}
else if (delta >= 0xfff0)
{
u8 diff = (0xffff - delta);
/* Sending node increased interval; undo history */
n->hello_map >>= diff;
n->hello_cnt = (diff < n->hello_cnt) ? n->hello_cnt - diff : 0;
}
else
{
/* Note state reset - flush entries */
n->hello_map = n->hello_cnt = 0;
}
/* Current entry */
n->hello_map = (n->hello_map << 1) | 1;
n->next_hello_seqno = seqno+1;
if (n->hello_cnt < 16) n->hello_cnt++;
/* Update expiration */
n->hello_expiry = current_time() + BABEL_HELLO_EXPIRY_FACTOR(interval);
n->last_hello_int = interval;
/* Disable initial timeout */
n->init_expiry = 0;
}
/*
* TLV handlers
*/
void
babel_handle_ack_req(union babel_msg *m, struct babel_iface *ifa)
{
struct babel_proto *p = ifa->proto;
struct babel_msg_ack_req *msg = &m->ack_req;
TRACE(D_PACKETS, "Handling ACK request nonce %d interval %t",
msg->nonce, (btime) msg->interval);
babel_send_ack(ifa, msg->sender, msg->nonce);
}
void
babel_handle_hello(union babel_msg *m, struct babel_iface *ifa)
{
struct babel_proto *p = ifa->proto;
struct babel_msg_hello *msg = &m->hello;
TRACE(D_PACKETS, "Handling hello seqno %d interval %t",
msg->seqno, (btime) msg->interval);
struct babel_neighbor *n = babel_get_neighbor(ifa, msg->sender);
struct babel_iface_config *cf = n->ifa->cf;
int first_hello = !n->hello_cnt;
if (msg->tstamp)
{
n->last_tstamp = msg->tstamp;
n->last_tstamp_rcvd = msg->pkt_received;
}
babel_update_hello_history(n, msg->seqno, msg->interval);
babel_update_cost(n);
/* Speed up session establishment by sending IHU immediately */
if (first_hello)
{
/* if using RTT, all IHUs must be paired with hellos */
if(cf->rtt_send)
babel_send_hello(ifa, 0);
else
babel_send_ihu(ifa, n);
}
}
static int
babel_btime_cmp(const void *b1, const void *b2)
{
btime r;
switch (r = *(btime*)b1 - *(btime*)b2)
{
case 0:
return 0;
break;
default:
return r > (btime)0 ? 1 : -1;
break;
}
}
void
babel_handle_ihu(union babel_msg *m, struct babel_iface *ifa)
{
struct babel_proto *p = ifa->proto;
struct babel_msg_ihu *msg = &m->ihu;
/* Ignore IHUs that are not about us */
if ((msg->ae != BABEL_AE_WILDCARD) && !ipa_equal(msg->addr, ifa->addr))
return;
TRACE(D_PACKETS, "Handling IHU rxcost %d interval %t",
msg->rxcost, (btime) msg->interval);
struct babel_neighbor *n = babel_get_neighbor(ifa, msg->sender);
n->txcost = msg->rxcost;
n->ihu_expiry = current_time() + BABEL_IHU_EXPIRY_FACTOR(msg->interval);
if (msg->tstamp)
{
u32 rtt_sample = 0, pkt_received = msg->pkt_received TO_US;
int remote_time, full_time;
/* processing time reported by peer */
remote_time = (n->last_tstamp - msg->tstamp_rcvd);
/* time since we sent the last timestamp - RTT including remote time */
full_time = (pkt_received - msg->tstamp);
/* sanity checks */
if (remote_time < 0 || full_time < 0 ||
remote_time US_ > BABEL_RTT_MAX_VALUE || full_time US_ > BABEL_RTT_MAX_VALUE)
goto out;
if (remote_time < full_time)
rtt_sample = full_time - remote_time;
if (n->srtt)
{
u16 pool_idx = n->srtt_poll_idx % n->ifa->cf->rtt_win_len;
n->srtt_poll_idx = pool_idx + 1;
*(n->srtt_pool + pool_idx) = rtt_sample;
if (n->srtt_pool_len < n->ifa->cf->rtt_win_len)
n->srtt_pool_len++;
memcpy(n->srtt_pool_sorted, n->srtt_pool, (size_t)n->srtt_pool_len*sizeof(btime));
// use qsort for now for testing
qsort(n->srtt_pool_sorted, (size_t)n->srtt_pool_len, sizeof(btime), babel_btime_cmp);
int mid = n->srtt_pool_len / (u16)2;
if (!n->srtt_pool_len || n->srtt_pool_len % (u16)2)
n->srtt = *(n->srtt_pool_sorted + mid);
else
n->srtt = (*(n->srtt_pool_sorted + mid - (u16)1) + *(n->srtt_pool_sorted + mid)) / (u16)2;
}
else {
*(n->srtt_pool) = n->srtt = rtt_sample;
n->srtt_poll_idx = n->srtt_pool_len = 1;
}
TRACE(D_EVENTS, "RTT sample for neighbour %I on %s: %u us (srtt %u.%03u ms)",
n->addr, ifa->ifname, rtt_sample, n->srtt/1000, n->srtt%1000);
}
out:
babel_update_cost(n);
}
/**
* babel_handle_update - handle incoming route updates
* @m: Incoming update TLV
* @ifa: Interface the update was received on
*
* This function is called as a handler for update TLVs and handles the updating
* and maintenance of route entries in Babel's internal routing cache. The
* handling follows the actions described in the Babel RFC, and at the end of
* each update handling, babel_select_route() is called on the affected entry to
* optionally update the selected routes and propagate them to the core.
*/
void
babel_handle_update(union babel_msg *m, struct babel_iface *ifa)
{
struct babel_proto *p = ifa->proto;
struct babel_msg_update *msg = &m->update;
struct babel_neighbor *nbr;
struct babel_entry *e;
struct babel_source *s;
struct babel_route *r, *best;
node *n;
int feasible, metric;
if (msg->wildcard)
TRACE(D_PACKETS, "Handling wildcard retraction", msg->seqno);
else
TRACE(D_PACKETS, "Handling update for %N with seqno %d metric %d",
&msg->net, msg->seqno, msg->metric);
nbr = babel_find_neighbor(ifa, msg->sender);
if (!nbr)
{
DBG("Babel: Haven't heard from neighbor %I; ignoring update.\n", msg->sender);
return;
}
if (msg->router_id == p->router_id)
{
DBG("Babel: Ignoring update for our own router ID.\n");
return;
}
struct channel *c = (msg->net.type == NET_IP4) ? p->ip4_channel : p->ip6_channel;
if (!c || (c->channel_state != CS_UP))
{
DBG("Babel: Ignoring update for inactive address family.\n");
return;
}
/* Retraction */
if (msg->metric == BABEL_INFINITY)
{
if (msg->wildcard)
{
/*
* Special case: This is a retraction of all prefixes announced by this
* neighbour (see second-to-last paragraph of section 4.4.9 in the RFC).
*/
WALK_LIST(n, nbr->routes)
{
r = SKIP_BACK(struct babel_route, neigh_route, n);
babel_retract_route(p, r);
}
}
else
{
e = babel_find_entry(p, &msg->net);
if (!e)
return;
/* The route entry indexed by neighbour */
r = babel_find_route(e, nbr);
if (!r)
return;
/* Router-id, next-hop and seqno are ignored for retractions */
babel_retract_route(p, r);
}
/* Done with retractions */
return;
}
/* Regular update */
e = babel_get_entry(p, &msg->net);
r = babel_get_route(p, e, nbr); /* the route entry indexed by neighbour */
s = babel_find_source(e, msg->router_id); /* for feasibility */
feasible = babel_is_feasible(s, msg->seqno, msg->metric);
metric = babel_compute_metric(nbr, msg->metric);
best = e->selected;
/* RFC section 3.8.2.2 - Dealing with unfeasible updates */
if (!feasible && (metric != BABEL_INFINITY) &&
(!best || (r == best) || (metric < best->metric)))
babel_add_seqno_request(p, e, s->router_id, s->seqno + 1, 0, nbr);
/* Special case - ignore unfeasible update to best route */
if (r == best && !feasible && (msg->router_id == r->router_id))
return;
r->expires = current_time() + BABEL_ROUTE_EXPIRY_FACTOR(msg->interval);
r->refresh_time = current_time() + BABEL_ROUTE_REFRESH_FACTOR(msg->interval);
/* No further processing if there is no change */
if ((r->feasible == feasible) && (r->seqno == msg->seqno) &&
(r->metric == metric) && (r->advert_metric == msg->metric) &&
(r->router_id == msg->router_id) && ipa_equal(r->next_hop, msg->next_hop))
return;
/* Last paragraph above - update the entry */
babel_update_metric(p, r, metric);
r->feasible = feasible;
r->seqno = msg->seqno;
r->advert_metric = msg->metric;
r->router_id = msg->router_id;
r->next_hop = msg->next_hop;
/* If received update satisfies seqno request, we send triggered updates */
if (babel_satisfy_seqno_request(p, e, msg->router_id, msg->seqno))
{
babel_trigger_update(p);
e->updated = current_time();
}
babel_select_route(p, e, r);
}
void
babel_handle_route_request(union babel_msg *m, struct babel_iface *ifa)
{
struct babel_proto *p = ifa->proto;
struct babel_msg_route_request *msg = &m->route_request;
/* RFC 6126 3.8.1.1 */
/* Wildcard request - full update on the interface */
if (msg->full)
{
TRACE(D_PACKETS, "Handling wildcard route request");
ifa->want_triggered = 1;
return;
}
TRACE(D_PACKETS, "Handling route request for %N", &msg->net);
/* Non-wildcard request - see if we have an entry for the route.
If not, send a retraction, otherwise send an update. */
struct babel_entry *e = babel_find_entry(p, &msg->net);
if (!e)
{
babel_send_retraction(ifa, &msg->net);
}
else
{
babel_trigger_iface_update(ifa);
e->updated = current_time();
}
}
void
babel_handle_seqno_request(union babel_msg *m, struct babel_iface *ifa)
{
struct babel_proto *p = ifa->proto;
struct babel_msg_seqno_request *msg = &m->seqno_request;
/* RFC 6126 3.8.1.2 */
TRACE(D_PACKETS, "Handling seqno request for %N router-id %lR seqno %d hop count %d",
&msg->net, msg->router_id, msg->seqno, msg->hop_count);
/* Ignore if we have no such entry or entry has infinite metric */
struct babel_entry *e = babel_find_entry(p, &msg->net);
if (!e || !e->valid || (e->metric == BABEL_INFINITY))
return;
/* Trigger update on incoming interface if we have a selected route with
different router id or seqno no smaller than requested */
if ((e->router_id != msg->router_id) || ge_mod64k(e->seqno, msg->seqno))
{
babel_trigger_iface_update(ifa);
e->updated = current_time();
return;
}
/* Seqno is larger; check if we own the router id */
if (msg->router_id == p->router_id)
{
/* Ours; seqno increase and trigger global update */
p->update_seqno_inc = 1;
babel_trigger_update(p);
}
else if (msg->hop_count > 1)
{
/* Not ours; forward if TTL allows it */
/* Find best admissible route */
struct babel_route *r, *best1 = NULL, *best2 = NULL;
WALK_LIST(r, e->routes)
if ((r->router_id == msg->router_id) && !ipa_equal(r->neigh->addr, msg->sender))
{
/* Find best feasible route */
if ((!best1 || r->metric < best1->metric) && r->feasible)
best1 = r;
/* Find best not necessary feasible route */
if (!best2 || r->metric < best2->metric)
best2 = r;
}
/* If no route is found, do nothing */
r = best1 ?: best2;
if (!r)
return;
babel_add_seqno_request(p, e, msg->router_id, msg->seqno, msg->hop_count-1, r->neigh);
}
}
/*
* Authentication functions
*/
/**
* babel_auth_reset_index - Reset authentication index on interface
* @ifa: Interface to reset
*
* This function resets the authentication index and packet counter for an
* interface, and should be called on interface configuration, or when the
* packet counter overflows.
*/
void
babel_auth_reset_index(struct babel_iface *ifa)
{
random_bytes(ifa->auth_index, BABEL_AUTH_INDEX_LEN);
ifa->auth_pc = 1;
}
static void
babel_auth_send_challenge_request(struct babel_iface *ifa, struct babel_neighbor *n)
{
struct babel_proto *p = ifa->proto;
union babel_msg msg = {};
TRACE(D_PACKETS, "Sending challenge request to %I on %s",
n->addr, ifa->ifname);
random_bytes(n->auth_nonce, BABEL_AUTH_NONCE_LEN);
n->auth_nonce_expiry = current_time() + BABEL_AUTH_CHALLENGE_TIMEOUT;
n->auth_next_challenge = current_time() + BABEL_AUTH_CHALLENGE_INTERVAL;
msg.type = BABEL_TLV_CHALLENGE_REQUEST;
msg.challenge.nonce_len = BABEL_AUTH_NONCE_LEN;
msg.challenge.nonce = n->auth_nonce;
babel_send_unicast(&msg, ifa, n->addr);
}
static void
babel_auth_send_challenge_reply(struct babel_iface *ifa, struct babel_neighbor *n, struct babel_msg_auth *rcv)
{
struct babel_proto *p = ifa->proto;
union babel_msg msg = {};
TRACE(D_PACKETS, "Sending challenge reply to %I on %s",
n->addr, ifa->ifname);
n->auth_next_challenge_reply = current_time() + BABEL_AUTH_CHALLENGE_INTERVAL;
msg.type = BABEL_TLV_CHALLENGE_REPLY;
msg.challenge.nonce_len = rcv->challenge_len;
msg.challenge.nonce = rcv->challenge;
babel_send_unicast(&msg, ifa, n->addr);
}
int
babel_auth_check_pc(struct babel_iface *ifa, struct babel_msg_auth *msg)
{
struct babel_proto *p = ifa->proto;
struct babel_neighbor *n;
/*
* We create the neighbour entry at this point because it makes it easier to
* rate limit challenge replies; this is explicitly allowed by the spec (see
* Section 4.3).
*/
n = babel_get_neighbor(ifa, msg->sender);
/* (3b) Handle challenge request */
if (msg->challenge_seen && (n->auth_next_challenge_reply <= current_time()))
babel_auth_send_challenge_reply(ifa, n, msg);
/* (4a) If PC TLV is missing, drop the packet */
if (!msg->pc_seen)
{
LOG_PKT_AUTH("Authentication failed for %I on %s - missing or invalid PC",
msg->sender, ifa->ifname);
return 0;
}
/* (4b) On successful challenge, update PC and index to current values */
if (msg->challenge_reply_seen &&
(n->auth_nonce_expiry > current_time()) &&
!memcmp(msg->challenge_reply, n->auth_nonce, BABEL_AUTH_NONCE_LEN))
{
n->auth_index_len = msg->index_len;
memcpy(n->auth_index, msg->index, msg->index_len);
n->auth_pc = msg->pc;
n->auth_passed = 1;
return 1;
}
/* (5) If index differs, send challenge and drop the packet */
if ((n->auth_index_len != msg->index_len) ||
memcmp(n->auth_index, msg->index, msg->index_len))
{
TRACE(D_PACKETS, "Index mismatch for packet from %I via %s",
msg->sender, ifa->ifname);
if (n->auth_next_challenge <= current_time())
babel_auth_send_challenge_request(ifa, n);
return 0;
}
/* (6) Index matches; only accept if PC is greater than last */
if (n->auth_pc >= msg->pc)
{
LOG_PKT_AUTH("Authentication failed for %I on %s - "
"lower packet counter (rcv %u, old %u)",
msg->sender, ifa->ifname, msg->pc, n->auth_pc);
return 0;
}
n->auth_pc = msg->pc;
n->auth_passed = 1;
return 1;
}
/*
* Babel interfaces
*/
/**
* babel_iface_timer - Babel interface timer handler
* @t: Timer
*
* This function is called by the per-interface timer and triggers sending of
* periodic Hello's and both triggered and periodic updates. Periodic Hello's
* and updates are simply handled by setting the next_{hello,regular} variables
* on the interface, and triggering an update (and resetting the variable)
* whenever 'now' exceeds that value.
*
* For triggered updates, babel_trigger_iface_update() will set the
* want_triggered field on the interface to a timestamp value. If this is set
* (and the next_triggered time has passed; this is a rate limiting mechanism),
* babel_send_update() will be called with this timestamp as the second
* parameter. This causes updates to be send consisting of only the routes that
* have changed since the time saved in want_triggered.
*
* Mostly when an update is triggered, the route being modified will be set to
* the value of 'now' at the time of the trigger; the >= comparison for
* selecting which routes to send in the update will make sure this is included.
*/
static void
babel_iface_timer(timer *t)
{
struct babel_iface *ifa = t->data;
struct babel_proto *p = ifa->proto;
btime hello_period = ifa->cf->hello_interval;
btime update_period = ifa->cf->update_interval;
btime now_ = current_time();
if (now_ >= ifa->next_hello)
{
babel_send_hello(ifa, 0);
ifa->next_hello += hello_period * (1 + (now_ - ifa->next_hello) / hello_period);
}
if (now_ >= ifa->next_regular)
{
TRACE(D_EVENTS, "Sending regular updates on %s", ifa->ifname);
babel_send_update(ifa, 0);
ifa->next_regular += update_period * (1 + (now_ - ifa->next_regular) / update_period);
ifa->want_triggered = 0;
p->triggered = 0;
}
else if (ifa->want_triggered && (now_ >= ifa->next_triggered))
{
TRACE(D_EVENTS, "Sending triggered updates on %s", ifa->ifname);
babel_send_update(ifa, ifa->want_triggered);
ifa->next_triggered = now_ + MIN(1 S, update_period / 2);
ifa->want_triggered = 0;
p->triggered = 0;
}
btime next_event = MIN(ifa->next_hello, ifa->next_regular);
if (ifa->want_triggered) next_event = MIN(next_event, ifa->next_triggered);
tm_set(ifa->timer, next_event);
}
static inline void
babel_iface_kick_timer(struct babel_iface *ifa)
{
if (ifa->timer->expires > (current_time() + 100 MS))
tm_start(ifa->timer, 100 MS);
}
static void
babel_iface_start(struct babel_iface *ifa)
{
struct babel_proto *p = ifa->proto;
TRACE(D_EVENTS, "Starting interface %s", ifa->ifname);
ifa->next_hello = current_time() + (random() % ifa->cf->hello_interval);
ifa->next_regular = current_time() + (random() % ifa->cf->update_interval);
ifa->next_triggered = current_time() + MIN(1 S, ifa->cf->update_interval / 2);
ifa->want_triggered = 0; /* We send an immediate update (below) */
tm_start(ifa->timer, 100 MS);
ifa->up = 1;
babel_send_hello(ifa, 0);
babel_send_wildcard_retraction(ifa);
babel_send_wildcard_request(ifa);
babel_send_update(ifa, 0); /* Full update */
}
static void
babel_iface_stop(struct babel_iface *ifa)
{
struct babel_proto *p = ifa->proto;
struct babel_neighbor *nbr;
struct babel_route *r;
node *n;
TRACE(D_EVENTS, "Stopping interface %s", ifa->ifname);
/*
* Rather than just flushing the neighbours, we set the metric of their routes
* to infinity. This allows us to keep the neighbour hello state for when the
* interface comes back up. The routes will also be kept until they expire.
*/
WALK_LIST(nbr, ifa->neigh_list)
{
WALK_LIST(n, nbr->routes)
{
r = SKIP_BACK(struct babel_route, neigh_route, n);
babel_retract_route(p, r);
}
}
tm_stop(ifa->timer);
ifa->up = 0;
}
static inline int
babel_iface_link_up(struct babel_iface *ifa)
{
return !ifa->cf->check_link || (ifa->iface->flags & IF_LINK_UP);
}
static void
babel_iface_update_state(struct babel_iface *ifa)
{
int up = ifa->sk && babel_iface_link_up(ifa);
if (up == ifa->up)
return;
if (up)
babel_iface_start(ifa);
else
babel_iface_stop(ifa);
}
static void
babel_iface_update_addr4(struct babel_iface *ifa)
{
struct babel_proto *p = ifa->proto;
ip_addr addr4 = ifa->iface->addr4 ? ifa->iface->addr4->ip : IPA_NONE;
ifa->next_hop_ip4 = ipa_nonzero(ifa->cf->next_hop_ip4) ? ifa->cf->next_hop_ip4 : addr4;
if (ipa_zero(ifa->next_hop_ip4) && p->ip4_channel)
log(L_WARN "%s: Missing IPv4 next hop address for %s", p->p.name, ifa->ifname);
if (ifa->up)
babel_iface_kick_timer(ifa);
}
static void
babel_iface_update_buffers(struct babel_iface *ifa)
{
if (!ifa->sk)
return;
uint mtu = MAX(BABEL_MIN_MTU, ifa->iface->mtu);
uint rbsize = ifa->cf->rx_buffer ?: mtu;
uint tbsize = ifa->cf->tx_length ?: mtu;
rbsize = MAX(rbsize, tbsize);
sk_set_rbsize(ifa->sk, rbsize);
sk_set_tbsize(ifa->sk, tbsize);
ifa->tx_length = tbsize - BABEL_OVERHEAD;
babel_auth_set_tx_overhead(ifa);
}
static struct babel_iface*
babel_find_iface(struct babel_proto *p, struct iface *what)
{
struct babel_iface *ifa;
WALK_LIST (ifa, p->interfaces)
if (ifa->iface == what)
return ifa;
return NULL;
}
static void
babel_iface_locked(struct object_lock *lock)
{
struct babel_iface *ifa = lock->data;
struct babel_proto *p = ifa->proto;
if (!babel_open_socket(ifa))
{
log(L_ERR "%s: Cannot open socket for %s", p->p.name, ifa->iface->name);
return;
}
babel_iface_update_buffers(ifa);
babel_iface_update_state(ifa);
}
static void
babel_add_iface(struct babel_proto *p, struct iface *new, struct babel_iface_config *ic)
{
struct babel_iface *ifa;
TRACE(D_EVENTS, "Adding interface %s", new->name);
pool *pool = rp_new(p->p.pool, new->name);
ifa = mb_allocz(pool, sizeof(struct babel_iface));
ifa->proto = p;
ifa->iface = new;
ifa->cf = ic;
ifa->pool = pool;
ifa->ifname = new->name;
ifa->addr = new->llv6->ip;
add_tail(&p->interfaces, NODE ifa);
ip_addr addr4 = new->addr4 ? new->addr4->ip : IPA_NONE;
ifa->next_hop_ip4 = ipa_nonzero(ic->next_hop_ip4) ? ic->next_hop_ip4 : addr4;
ifa->next_hop_ip6 = ipa_nonzero(ic->next_hop_ip6) ? ic->next_hop_ip6 : ifa->addr;
if (ipa_zero(ifa->next_hop_ip4) && p->ip4_channel)
log(L_WARN "%s: Missing IPv4 next hop address for %s", p->p.name, new->name);
init_list(&ifa->neigh_list);
ifa->hello_seqno = 1;
if (ic->auth_type != BABEL_AUTH_NONE)
babel_auth_reset_index(ifa);
ifa->timer = tm_new_init(ifa->pool, babel_iface_timer, ifa, 0, 0);
init_list(&ifa->msg_queue);
ifa->send_event = ev_new_init(ifa->pool, babel_send_queue, ifa);
struct object_lock *lock = olock_new(ifa->pool);
lock->type = OBJLOCK_UDP;
lock->addr = IP6_BABEL_ROUTERS;
lock->port = ifa->cf->port;
lock->iface = ifa->iface;
lock->hook = babel_iface_locked;
lock->data = ifa;
olock_acquire(lock);
}
static void
babel_remove_iface(struct babel_proto *p, struct babel_iface *ifa)
{
TRACE(D_EVENTS, "Removing interface %s", ifa->iface->name);
struct babel_neighbor *n;
WALK_LIST_FIRST(n, ifa->neigh_list)
babel_flush_neighbor(p, n);
rem_node(NODE ifa);
rfree(ifa->pool); /* contains ifa itself, locks, socket, etc */
}
static int
iface_is_valid(struct babel_proto *p, struct iface *iface)
{
if (!(iface->flags & IF_MULTICAST))
{
log(L_ERR "%s: Interface %s does not support multicast",
p->p.name, iface->name);
return 0;
}
return 1;
}
static void
babel_if_notify(struct proto *P, unsigned flags, struct iface *iface)
{
struct babel_proto *p = (void *) P;
struct babel_config *cf = (void *) P->cf;
struct babel_iface *ifa = babel_find_iface(p, iface);
if (iface->flags & IF_IGNORE)
return;
/* Add, remove or restart interface */
if (flags & (IF_CHANGE_UPDOWN | IF_CHANGE_LLV6))
{
if (ifa)
babel_remove_iface(p, ifa);
if (!(iface->flags & IF_UP))
return;
/* Ignore ifaces without link-local address */
if (!iface->llv6)
return;
struct babel_iface_config *ic = (void *) iface_patt_find(&cf->iface_list, iface, NULL);
if (ic && iface_is_valid(p, iface))
babel_add_iface(p, iface, ic);
return;
}
if (!ifa)
return;
if (flags & IF_CHANGE_ADDR4)
babel_iface_update_addr4(ifa);
if (flags & IF_CHANGE_MTU)
babel_iface_update_buffers(ifa);
if (flags & IF_CHANGE_LINK)
babel_iface_update_state(ifa);
}
static int
babel_reconfigure_iface(struct babel_proto *p, struct babel_iface *ifa, struct babel_iface_config *new)
{
struct babel_iface_config *old = ifa->cf;
/* Change of these options would require to reset the iface socket */
if ((new->port != old->port) ||
(new->tx_tos != old->tx_tos) ||
(new->tx_priority != old->tx_priority))
return 0;
TRACE(D_EVENTS, "Reconfiguring interface %s", ifa->iface->name);
ifa->cf = new;
ip_addr addr4 = ifa->iface->addr4 ? ifa->iface->addr4->ip : IPA_NONE;
ifa->next_hop_ip4 = ipa_nonzero(new->next_hop_ip4) ? new->next_hop_ip4 : addr4;
ifa->next_hop_ip6 = ipa_nonzero(new->next_hop_ip6) ? new->next_hop_ip6 : ifa->addr;
babel_iface_update_buffers(ifa);
if ((new->auth_type != BABEL_AUTH_NONE) && (new->auth_type != old->auth_type))
babel_auth_reset_index(ifa);
if (ipa_zero(ifa->next_hop_ip4) && p->ip4_channel)
log(L_WARN "%s: Missing IPv4 next hop address for %s", p->p.name, ifa->ifname);
if (ifa->next_hello > (current_time() + new->hello_interval))
ifa->next_hello = current_time() + (random() % new->hello_interval);
if (ifa->next_regular > (current_time() + new->update_interval))
ifa->next_regular = current_time() + (random() % new->update_interval);
if (new->check_link != old->check_link)
babel_iface_update_state(ifa);
if (ifa->up)
babel_iface_kick_timer(ifa);
return 1;
}
static void
babel_reconfigure_ifaces(struct babel_proto *p, struct babel_config *cf)
{
struct iface *iface;
WALK_LIST(iface, iface_list)
{
if (!(iface->flags & IF_UP))
continue;
/* Ignore ifaces without link-local address */
if (!iface->llv6)
continue;
struct babel_iface *ifa = babel_find_iface(p, iface);
struct babel_iface_config *ic = (void *) iface_patt_find(&cf->iface_list, iface, NULL);
if (ic && !iface_is_valid(p, iface))
ic = NULL;
if (ifa && ic)
{
if (babel_reconfigure_iface(p, ifa, ic))
continue;
/* Hard restart */
log(L_INFO "%s: Restarting interface %s", p->p.name, ifa->iface->name);
babel_remove_iface(p, ifa);
babel_add_iface(p, iface, ic);
}
if (ifa && !ic)
babel_remove_iface(p, ifa);
if (!ifa && ic)
babel_add_iface(p, iface, ic);
}
}
/*
* Debugging and info output functions
*/
static void
babel_dump_source(struct babel_source *s)
{
debug("Source router_id %lR seqno %d metric %d expires %t\n",
s->router_id, s->seqno, s->metric,
s->expires ? s->expires - current_time() : 0);
}
static void
babel_dump_route(struct babel_route *r)
{
debug("Route neigh %I if %s seqno %d metric %d/%d router_id %lR expires %t\n",
r->neigh->addr, r->neigh->ifa->ifname, r->seqno, r->advert_metric, r->metric,
r->router_id, r->expires ? r->expires - current_time() : 0);
}
static void
babel_dump_entry(struct babel_entry *e)
{
struct babel_source *s;
struct babel_route *r;
debug("Babel: Entry %N:\n", e->n.addr);
WALK_LIST(s,e->sources)
{ debug(" "); babel_dump_source(s); }
WALK_LIST(r,e->routes)
{
debug(" ");
if (r == e->selected) debug("*");
babel_dump_route(r);
}
}
static void
babel_dump_neighbor(struct babel_neighbor *n)
{
debug("Neighbor %I txcost %d hello_map %x next seqno %d expires %t/%t\n",
n->addr, n->txcost, n->hello_map, n->next_hello_seqno,
n->hello_expiry ? n->hello_expiry - current_time() : 0,
n->ihu_expiry ? n->ihu_expiry - current_time() : 0);
}
static void
babel_dump_iface(struct babel_iface *ifa)
{
struct babel_neighbor *n;
debug("Babel: Interface %s addr %I rxcost %d type %d hello seqno %d intervals %t %t",
ifa->ifname, ifa->addr, ifa->cf->rxcost, ifa->cf->type, ifa->hello_seqno,
ifa->cf->hello_interval, ifa->cf->update_interval);
debug(" next hop v4 %I next hop v6 %I\n", ifa->next_hop_ip4, ifa->next_hop_ip6);
WALK_LIST(n, ifa->neigh_list)
{ debug(" "); babel_dump_neighbor(n); }
}
static void
babel_dump(struct proto *P)
{
struct babel_proto *p = (struct babel_proto *) P;
struct babel_iface *ifa;
debug("Babel: router id %lR update seqno %d\n", p->router_id, p->update_seqno);
WALK_LIST(ifa, p->interfaces)
babel_dump_iface(ifa);
FIB_WALK(&p->ip4_rtable, struct babel_entry, e)
{
babel_dump_entry(e);
}
FIB_WALK_END;
FIB_WALK(&p->ip6_rtable, struct babel_entry, e)
{
babel_dump_entry(e);
}
FIB_WALK_END;
}
static void
babel_get_route_info(rte *rte, byte *buf)
{
u64 rid = 0;
eattr *e = ea_find(rte->attrs->eattrs, EA_BABEL_ROUTER_ID);
if (e)
memcpy(&rid, e->u.ptr->data, sizeof(u64));
buf += bsprintf(buf, " (%d/%d) [%lR]", rte->attrs->pref,
ea_get_int(rte->attrs->eattrs, EA_BABEL_METRIC, BABEL_INFINITY), rid);
}
static int
babel_get_attr(const eattr *a, byte *buf, int buflen UNUSED)
{
switch (a->id)
{
case EA_BABEL_SEQNO:
return GA_FULL;
case EA_BABEL_METRIC:
bsprintf(buf, "metric: %d", a->u.data);
return GA_FULL;
case EA_BABEL_ROUTER_ID:
{
u64 rid = 0;
memcpy(&rid, a->u.ptr->data, sizeof(u64));
bsprintf(buf, "router_id: %lR", rid);
return GA_FULL;
}
default:
return GA_UNKNOWN;
}
}
void
babel_show_interfaces(struct proto *P, const char *iff)
{
struct babel_proto *p = (void *) P;
struct babel_iface *ifa = NULL;
struct babel_neighbor *nbr = NULL;
if (p->p.proto_state != PS_UP)
{
cli_msg(-1023, "%s: is not up", p->p.name);
return;
}
cli_msg(-1023, "%s:", p->p.name);
cli_msg(-1023, "%-10s %-6s %-5s %7s %6s %7s %-15s %s",
"Interface", "State", "Auth", "RX cost", "Nbrs", "Timer",
"Next hop (v4)", "Next hop (v6)");
WALK_LIST(ifa, p->interfaces)
{
if (iff && !patmatch(iff, ifa->iface->name))
continue;
int nbrs = 0;
WALK_LIST(nbr, ifa->neigh_list)
nbrs++;
btime timer = MIN(ifa->next_regular, ifa->next_hello) - current_time();
cli_msg(-1023, "%-10s %-6s %-5s %7u %6u %7t %-15I %I",
ifa->iface->name, (ifa->up ? "Up" : "Down"),
(ifa->cf->auth_type == BABEL_AUTH_MAC ?
(ifa->cf->auth_permissive ? "Perm" : "Yes") : "No"),
ifa->cf->rxcost, nbrs, MAX(timer, 0),
ifa->next_hop_ip4, ifa->next_hop_ip6);
}
}
void
babel_show_neighbors(struct proto *P, const char *iff)
{
struct babel_proto *p = (void *) P;
struct babel_iface *ifa = NULL;
struct babel_neighbor *n = NULL;
struct babel_route *r = NULL;
if (p->p.proto_state != PS_UP)
{
cli_msg(-1024, "%s: is not up", p->p.name);
return;
}
cli_msg(-1024, "%s:", p->p.name);
cli_msg(-1024, "%-25s %-10s %6s %6s %6s %7s %4s %11s",
"IP address", "Interface", "Metric", "Routes", "Hellos", "Expires", "Auth", "RTT");
WALK_LIST(ifa, p->interfaces)
{
if (iff && !patmatch(iff, ifa->iface->name))
continue;
WALK_LIST(n, ifa->neigh_list)
{
int rts = 0;
WALK_LIST(r, n->routes)
rts++;
uint hellos = u32_popcount(n->hello_map);
btime timer = (n->hello_expiry ?: n->init_expiry) - current_time();
cli_msg(-1024, "%-25I %-10s %6u %6u %6u %7t %-4s %5u.%03ums",
n->addr, ifa->iface->name, n->cost, rts, hellos, MAX(timer, 0),
n->auth_passed ? "Yes" : "No",
n->srtt/1000, n->srtt%1000);
}
}
}
static void
babel_show_entries_(struct babel_proto *p, struct fib *rtable)
{
int width = babel_sadr_enabled(p) ? -54 : -24;
FIB_WALK(rtable, struct babel_entry, e)
{
struct babel_route *r = NULL;
uint rts = 0, srcs = 0;
node *n;
WALK_LIST(n, e->routes)
rts++;
WALK_LIST(n, e->sources)
srcs++;
if (e->valid)
cli_msg(-1025, "%-*N %-23lR %6u %5u %7u %7u", width,
e->n.addr, e->router_id, e->metric, e->seqno, rts, srcs);
else if (r = e->selected)
cli_msg(-1025, "%-*N %-23lR %6u %5u %7u %7u", width,
e->n.addr, r->router_id, r->metric, r->seqno, rts, srcs);
else
cli_msg(-1025, "%-*N %-23s %6s %5s %7u %7u", width,
e->n.addr, "<none>", "-", "-", rts, srcs);
}
FIB_WALK_END;
}
void
babel_show_entries(struct proto *P)
{
struct babel_proto *p = (void *) P;
int width = babel_sadr_enabled(p) ? -54 : -24;
if (p->p.proto_state != PS_UP)
{
cli_msg(-1025, "%s: is not up", p->p.name);
return;
}
cli_msg(-1025, "%s:", p->p.name);
cli_msg(-1025, "%-*s %-23s %6s %5s %7s %7s", width,
"Prefix", "Router ID", "Metric", "Seqno", "Routes", "Sources");
babel_show_entries_(p, &p->ip4_rtable);
babel_show_entries_(p, &p->ip6_rtable);
}
static void
babel_show_routes_(struct babel_proto *p, struct fib *rtable)
{
int width = babel_sadr_enabled(p) ? -54 : -24;
FIB_WALK(rtable, struct babel_entry, e)
{
struct babel_route *r;
WALK_LIST(r, e->routes)
{
char c = (r == e->selected) ? '*' : (r->feasible ? '+' : ' ');
btime time = r->expires ? r->expires - current_time() : 0;
cli_msg(-1025, "%-*N %-25I %-10s %5u %c %5u %7t", width,
e->n.addr, r->next_hop, r->neigh->ifa->ifname,
r->metric, c, r->seqno, MAX(time, 0));
}
}
FIB_WALK_END;
}
void
babel_show_routes(struct proto *P)
{
struct babel_proto *p = (void *) P;
int width = babel_sadr_enabled(p) ? -54 : -24;
if (p->p.proto_state != PS_UP)
{
cli_msg(-1025, "%s: is not up", p->p.name);
return;
}
cli_msg(-1025, "%s:", p->p.name);
cli_msg(-1025, "%-*s %-25s %-9s %6s F %5s %7s", width,
"Prefix", "Nexthop", "Interface", "Metric", "Seqno", "Expires");
babel_show_routes_(p, &p->ip4_rtable);
babel_show_routes_(p, &p->ip6_rtable);
}
/*
* Babel protocol glue
*/
/**
* babel_timer - global timer hook
* @t: Timer
*
* This function is called by the global protocol instance timer and handles
* expiration of routes and neighbours as well as pruning of the seqno request
* cache.
*/
static void
babel_timer(timer *t)
{
struct babel_proto *p = t->data;
babel_expire_routes(p);
babel_expire_neighbors(p);
}
static inline void
babel_kick_timer(struct babel_proto *p)
{
if (p->timer->expires > (current_time() + 100 MS))
tm_start(p->timer, 100 MS);
}
static int
babel_preexport(struct channel *C, struct rte *new)
{
struct rta *a = new->attrs;
/* Reject our own unreachable routes */
if ((a->dest == RTD_UNREACHABLE) && (new->src->proto == C->proto))
return -1;
return 0;
}
/*
* babel_rt_notify - core tells us about new route (possibly our own),
* so store it into our data structures.
*/
static void
babel_rt_notify(struct proto *P, struct channel *c UNUSED, struct network *net,
struct rte *new, struct rte *old UNUSED)
{
struct babel_proto *p = (void *) P;
struct babel_entry *e;
if (new)
{
/* Update */
uint rt_seqno;
uint rt_metric = ea_get_int(new->attrs->eattrs, EA_BABEL_METRIC, 0);
u64 rt_router_id = 0;
if (new->src->proto == P)
{
rt_seqno = ea_find(new->attrs->eattrs, EA_BABEL_SEQNO)->u.data;
eattr *e = ea_find(new->attrs->eattrs, EA_BABEL_ROUTER_ID);
if (e)
memcpy(&rt_router_id, e->u.ptr->data, sizeof(u64));
}
else
{
rt_seqno = p->update_seqno;
rt_router_id = p->router_id;
}
if (rt_metric > BABEL_INFINITY)
{
log(L_WARN "%s: Invalid babel_metric value %u for route %N",
p->p.name, rt_metric, net->n.addr);
rt_metric = BABEL_INFINITY;
}
e = babel_get_entry(p, net->n.addr);
/* Activate triggered updates */
if ((e->valid != BABEL_ENTRY_VALID) ||
(e->router_id != rt_router_id))
{
babel_trigger_update(p);
e->updated = current_time();
}
e->valid = BABEL_ENTRY_VALID;
e->seqno = rt_seqno;
e->metric = rt_metric;
e->router_id = rt_router_id;
}
else
{
/* Withdraw */
e = babel_find_entry(p, net->n.addr);
if (!e || e->valid != BABEL_ENTRY_VALID)
return;
e->valid = BABEL_ENTRY_STALE;
e->metric = BABEL_INFINITY;
babel_trigger_update(p);
e->updated = current_time();
}
}
static int
babel_rte_better(struct rte *new, struct rte *old)
{
uint new_metric = ea_get_int(new->attrs->eattrs, EA_BABEL_METRIC, BABEL_INFINITY);
uint old_metric = ea_get_int(old->attrs->eattrs, EA_BABEL_METRIC, BABEL_INFINITY);
return new_metric < old_metric;
}
static u32
babel_rte_igp_metric(struct rte *rt)
{
return ea_get_int(rt->attrs->eattrs, EA_BABEL_METRIC, BABEL_INFINITY);
}
static void
babel_postconfig(struct proto_config *CF)
{
struct babel_config *cf = (void *) CF;
struct channel_config *ip4, *ip6, *ip6_sadr;
ip4 = proto_cf_find_channel(CF, NET_IP4);
ip6 = proto_cf_find_channel(CF, NET_IP6);
ip6_sadr = proto_cf_find_channel(CF, NET_IP6_SADR);
if (ip6 && ip6_sadr)
cf_error("Both ipv6 and ipv6-sadr channels");
cf->ip4_channel = ip4;
cf->ip6_channel = ip6 ?: ip6_sadr;
}
static struct proto *
babel_init(struct proto_config *CF)
{
struct proto *P = proto_new(CF);
struct babel_proto *p = (void *) P;
struct babel_config *cf = (void *) CF;
proto_configure_channel(P, &p->ip4_channel, cf->ip4_channel);
proto_configure_channel(P, &p->ip6_channel, cf->ip6_channel);
P->if_notify = babel_if_notify;
P->rt_notify = babel_rt_notify;
P->preexport = babel_preexport;
P->rte_better = babel_rte_better;
P->rte_igp_metric = babel_rte_igp_metric;
return P;
}
static inline void
babel_randomize_router_id(struct babel_proto *p)
{
p->router_id &= (u64) 0xffffffff;
p->router_id |= ((u64) random()) << 32;
TRACE(D_EVENTS, "Randomized router ID to %lR", p->router_id);
}
static int
babel_start(struct proto *P)
{
struct babel_proto *p = (void *) P;
struct babel_config *cf = (void *) P->cf;
u8 ip6_type = cf->ip6_channel ? cf->ip6_channel->net_type : NET_IP6;
fib_init(&p->ip4_rtable, P->pool, NET_IP4, sizeof(struct babel_entry),
OFFSETOF(struct babel_entry, n), 0, babel_init_entry);
fib_init(&p->ip6_rtable, P->pool, ip6_type, sizeof(struct babel_entry),
OFFSETOF(struct babel_entry, n), 0, babel_init_entry);
init_list(&p->interfaces);
p->timer = tm_new_init(P->pool, babel_timer, p, 1 S, 0);
tm_start(p->timer, 1 S);
p->update_seqno = 1;
p->router_id = proto_get_router_id(&cf->c);
if (cf->randomize_router_id)
babel_randomize_router_id(p);
p->route_slab = sl_new(P->pool, sizeof(struct babel_route));
p->source_slab = sl_new(P->pool, sizeof(struct babel_source));
p->msg_slab = sl_new(P->pool, sizeof(struct babel_msg_node));
p->seqno_slab = sl_new(P->pool, sizeof(struct babel_seqno_request));
p->log_pkt_tbf = (struct tbf){ .rate = 1, .burst = 5 };
return PS_UP;
}
static inline void
babel_iface_shutdown(struct babel_iface *ifa)
{
if (ifa->sk)
{
/*
* Retract all our routes and lower the hello interval so peers' neighbour
* state expires quickly
*/
babel_send_hello(ifa, BABEL_MIN_INTERVAL);
babel_send_wildcard_retraction(ifa);
babel_send_queue(ifa);
}
}
static int
babel_shutdown(struct proto *P)
{
struct babel_proto *p = (void *) P;
struct babel_iface *ifa;
TRACE(D_EVENTS, "Shutdown requested");
WALK_LIST(ifa, p->interfaces)
babel_iface_shutdown(ifa);
return PS_DOWN;
}
static int
babel_reconfigure(struct proto *P, struct proto_config *CF)
{
struct babel_proto *p = (void *) P;
struct babel_config *new = (void *) CF;
u8 ip6_type = new->ip6_channel ? new->ip6_channel->net_type : NET_IP6;
TRACE(D_EVENTS, "Reconfiguring");
if (p->ip6_rtable.addr_type != ip6_type)
return 0;
if (!proto_configure_channel(P, &p->ip4_channel, new->ip4_channel) ||
!proto_configure_channel(P, &p->ip6_channel, new->ip6_channel))
return 0;
p->p.cf = CF;
babel_reconfigure_ifaces(p, new);
babel_trigger_update(p);
babel_kick_timer(p);
return 1;
}
struct protocol proto_babel = {
.name = "Babel",
.template = "babel%d",
.class = PROTOCOL_BABEL,
.preference = DEF_PREF_BABEL,
.channel_mask = NB_IP | NB_IP6_SADR,
.proto_size = sizeof(struct babel_proto),
.config_size = sizeof(struct babel_config),
.postconfig = babel_postconfig,
.init = babel_init,
.dump = babel_dump,
.start = babel_start,
.shutdown = babel_shutdown,
.reconfigure = babel_reconfigure,
.get_route_info = babel_get_route_info,
.get_attr = babel_get_attr
};
void
babel_build(void)
{
proto_build(&proto_babel);
}
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