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zebra: support nh resolution without a route
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Start reorg of zebra nexthop-resolution so that we can use the
resolution logic for nexthop-groups as well as routes. Change
the signature of the core nexthop_active() api so that it does
not require a route-entry or route-node. Move some of the logic
around so that nexthop-specific logic is in nexthop_active(),
while route-oriented logic is in nexthop_active_check().

Signed-off-by: Mark Stapp <mjs@voltanet.io>
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Mark Stapp committed Feb 19, 2021
1 parent dc86ef7 commit 9b4ab90
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Showing 2 changed files with 121 additions and 68 deletions.
186 changes: 119 additions & 67 deletions zebra/zebra_nhg.c
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Original file line number Diff line number Diff line change
Expand Up @@ -371,8 +371,8 @@ void zebra_nhe_init(struct nhg_hash_entry *nhe, afi_t afi,
*/
if (nh && (nh->next == NULL)) {
switch (nh->type) {
case (NEXTHOP_TYPE_IFINDEX):
case (NEXTHOP_TYPE_BLACKHOLE):
case NEXTHOP_TYPE_IFINDEX:
case NEXTHOP_TYPE_BLACKHOLE:
/*
* This switch case handles setting the afi different
* for ipv4/v6 routes. Ifindex/blackhole nexthop
Expand All @@ -383,12 +383,12 @@ void zebra_nhe_init(struct nhg_hash_entry *nhe, afi_t afi,
*/
nhe->afi = afi;
break;
case (NEXTHOP_TYPE_IPV4_IFINDEX):
case (NEXTHOP_TYPE_IPV4):
case NEXTHOP_TYPE_IPV4_IFINDEX:
case NEXTHOP_TYPE_IPV4:
nhe->afi = AFI_IP;
break;
case (NEXTHOP_TYPE_IPV6_IFINDEX):
case (NEXTHOP_TYPE_IPV6):
case NEXTHOP_TYPE_IPV6_IFINDEX:
case NEXTHOP_TYPE_IPV6:
nhe->afi = AFI_IP6;
break;
}
Expand Down Expand Up @@ -1789,8 +1789,9 @@ static bool nexthop_valid_resolve(const struct nexthop *nexthop,
* if at all possible. Set the nexthop->ifindex and resolved_id
* as appropriate
*/
static int nexthop_active(afi_t afi, struct route_entry *re,
struct nexthop *nexthop, struct route_node *top)
static int nexthop_active(afi_t afi, struct nexthop *nexthop,
const struct prefix *top, int type, uint32_t flags,
uint32_t *pmtu)
{
struct prefix p;
struct route_table *table;
Expand All @@ -1805,33 +1806,58 @@ static int nexthop_active(afi_t afi, struct route_entry *re,
struct in_addr local_ipv4;
struct in_addr *ipv4;

/* Reset some nexthop attributes that we'll recompute if necessary */
if ((nexthop->type == NEXTHOP_TYPE_IPV4)
|| nexthop->type == NEXTHOP_TYPE_IPV6)
|| (nexthop->type == NEXTHOP_TYPE_IPV6))
nexthop->ifindex = 0;


UNSET_FLAG(nexthop->flags, NEXTHOP_FLAG_RECURSIVE);
nexthops_free(nexthop->resolved);
nexthop->resolved = NULL;
re->nexthop_mtu = 0;

if (IS_ZEBRA_DEBUG_NHG_DETAIL)
zlog_debug("%s: re %p, nexthop %pNHv",
__func__, re, nexthop);

/*
* If the kernel has sent us a NEW route, then
* by golly gee whiz it's a good route.
*
* If its an already INSTALLED route we have already handled, then the
* kernel route's nexthop might have became unreachable
* and we have to handle that.
* Some nexthop types get special handling, possibly skipping
* the normal processing.
*/
if (!CHECK_FLAG(re->status, ROUTE_ENTRY_INSTALLED)
&& (re->type == ZEBRA_ROUTE_KERNEL
|| re->type == ZEBRA_ROUTE_SYSTEM))
switch (nexthop->type) {
case NEXTHOP_TYPE_IFINDEX:
ifp = if_lookup_by_index(nexthop->ifindex, nexthop->vrf_id);
/*
* If the interface exists and its operative or its a kernel
* route and interface is up, its active. We trust kernel routes
* to be good.
*/
if (ifp
&& (if_is_operative(ifp)
|| (if_is_up(ifp)
&& (type == ZEBRA_ROUTE_KERNEL
|| type == ZEBRA_ROUTE_SYSTEM))))
return 1;
else
return 0;
break;

case NEXTHOP_TYPE_IPV6_IFINDEX:
if (IN6_IS_ADDR_LINKLOCAL(&nexthop->gate.ipv6)) {
ifp = if_lookup_by_index(nexthop->ifindex,
nexthop->vrf_id);
if (ifp && if_is_operative(ifp))
return 1;
else
return 0;
}
break;

case NEXTHOP_TYPE_BLACKHOLE:
return 1;

case NEXTHOP_TYPE_IPV4:
case NEXTHOP_TYPE_IPV4_IFINDEX:
case NEXTHOP_TYPE_IPV6:
default:
break;
}

/*
* If the nexthop has been marked as 'onlink' we just need to make
* sure the nexthop's interface is known and is operational.
Expand All @@ -1853,10 +1879,11 @@ static int nexthop_active(afi_t afi, struct route_entry *re,
return 1;
}

if ((top->p.family == AF_INET && top->p.prefixlen == 32
&& nexthop->gate.ipv4.s_addr == top->p.u.prefix4.s_addr)
|| (top->p.family == AF_INET6 && top->p.prefixlen == 128
&& memcmp(&nexthop->gate.ipv6, &top->p.u.prefix6, 16) == 0)) {
if (top &&
((top->family == AF_INET && top->prefixlen == 32
&& nexthop->gate.ipv4.s_addr == top->u.prefix4.s_addr)
|| (top->family == AF_INET6 && top->prefixlen == 128
&& memcmp(&nexthop->gate.ipv6, &top->u.prefix6, 16) == 0))) {
if (IS_ZEBRA_DEBUG_RIB_DETAILED)
zlog_debug(
" :%s: Attempting to install a max prefixlength route through itself",
Expand All @@ -1873,6 +1900,9 @@ static int nexthop_active(afi_t afi, struct route_entry *re,
ipv4 = &nexthop->gate.ipv4;
}

/* Processing for nexthops with SR 'color' attribute, using
* the corresponding SR policy object.
*/
if (nexthop->srte_color) {
struct ipaddr endpoint = {0};
struct zebra_sr_policy *policy;
Expand Down Expand Up @@ -1950,7 +1980,7 @@ static int nexthop_active(afi_t afi, struct route_entry *re,
* resolved by a route NH1. The exception is if the route is a
* host route.
*/
if (rn == top)
if (prefix_same(&rn->p, top))
if (((afi == AFI_IP) && (rn->p.prefixlen != 32))
|| ((afi == AFI_IP6) && (rn->p.prefixlen != 128))) {
if (IS_ZEBRA_DEBUG_RIB_DETAILED)
Expand Down Expand Up @@ -2020,7 +2050,7 @@ static int nexthop_active(afi_t afi, struct route_entry *re,
match->nhe->id, newhop);

return 1;
} else if (CHECK_FLAG(re->flags, ZEBRA_FLAG_ALLOW_RECURSION)) {
} else if (CHECK_FLAG(flags, ZEBRA_FLAG_ALLOW_RECURSION)) {
struct nexthop_group *nhg;

resolved = 0;
Expand Down Expand Up @@ -2079,10 +2109,14 @@ static int nexthop_active(afi_t afi, struct route_entry *re,
NULL);
resolved = 1;
}

done_with_match:
if (resolved)
re->nexthop_mtu = match->mtu;
else if (IS_ZEBRA_DEBUG_RIB_DETAILED)
/* Capture resolving mtu */
if (resolved) {
if (pmtu)
*pmtu = match->mtu;

} else if (IS_ZEBRA_DEBUG_RIB_DETAILED)
zlog_debug(
" %s: Recursion failed to find",
__func__);
Expand All @@ -2092,9 +2126,9 @@ static int nexthop_active(afi_t afi, struct route_entry *re,
if (IS_ZEBRA_DEBUG_RIB_DETAILED) {
zlog_debug(
" %s: Route Type %s has not turned on recursion",
__func__, zebra_route_string(re->type));
if (re->type == ZEBRA_ROUTE_BGP
&& !CHECK_FLAG(re->flags, ZEBRA_FLAG_IBGP))
__func__, zebra_route_string(type));
if (type == ZEBRA_ROUTE_BGP
&& !CHECK_FLAG(flags, ZEBRA_FLAG_IBGP))
zlog_debug(
" EBGP: see \"disable-ebgp-connected-route-check\" or \"disable-connected-check\"");
}
Expand All @@ -2113,20 +2147,17 @@ static int nexthop_active(afi_t afi, struct route_entry *re,
* appropriately as well. An existing route map can turn an
* otherwise active nexthop into inactive, but not vice versa.
*
* If it finds a nexthop recursively, set the resolved_id
* to match that nexthop's nhg_hash_entry ID;
*
* The return value is the final value of 'ACTIVE' flag.
*/
static unsigned nexthop_active_check(struct route_node *rn,
struct route_entry *re,
struct nexthop *nexthop)
{
struct interface *ifp;
route_map_result_t ret = RMAP_PERMITMATCH;
afi_t family;
const struct prefix *p, *src_p;
struct zebra_vrf *zvrf;
uint32_t mtu = 0;

srcdest_rnode_prefixes(rn, &p, &src_p);

Expand All @@ -2137,34 +2168,45 @@ static unsigned nexthop_active_check(struct route_node *rn,
else
family = 0;

if (IS_ZEBRA_DEBUG_NHG_DETAIL)
zlog_debug("%s: re %p, nexthop %pNHv", __func__, re, nexthop);

/*
* If the kernel has sent us a NEW route, then
* by golly gee whiz it's a good route.
*
* If its an already INSTALLED route we have already handled, then the
* kernel route's nexthop might have became unreachable
* and we have to handle that.
*/
if (!CHECK_FLAG(re->status, ROUTE_ENTRY_INSTALLED) &&
(re->type == ZEBRA_ROUTE_KERNEL ||
re->type == ZEBRA_ROUTE_SYSTEM)) {
SET_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE);
goto skip_check;
}

switch (nexthop->type) {
case NEXTHOP_TYPE_IFINDEX:
ifp = if_lookup_by_index(nexthop->ifindex, nexthop->vrf_id);
/*
* If the interface exists and its operative or its a kernel
* route and interface is up, its active. We trust kernel routes
* to be good.
*/
if (ifp
&& (if_is_operative(ifp)
|| (if_is_up(ifp)
&& (re->type == ZEBRA_ROUTE_KERNEL
|| re->type == ZEBRA_ROUTE_SYSTEM))))
if (nexthop_active(AFI_IP, nexthop, &rn->p, re->type,
re->flags, &mtu))
SET_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE);
else
UNSET_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE);
break;
case NEXTHOP_TYPE_IPV4:
case NEXTHOP_TYPE_IPV4_IFINDEX:
family = AFI_IP;
if (nexthop_active(AFI_IP, re, nexthop, rn))
if (nexthop_active(AFI_IP, nexthop, &rn->p, re->type,
re->flags, &mtu))
SET_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE);
else
UNSET_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE);
break;
case NEXTHOP_TYPE_IPV6:
family = AFI_IP6;
if (nexthop_active(AFI_IP6, re, nexthop, rn))
if (nexthop_active(AFI_IP6, nexthop, &rn->p, re->type,
re->flags, &mtu))
SET_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE);
else
UNSET_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE);
Expand All @@ -2173,19 +2215,12 @@ static unsigned nexthop_active_check(struct route_node *rn,
/* RFC 5549, v4 prefix with v6 NH */
if (rn->p.family != AF_INET)
family = AFI_IP6;
if (IN6_IS_ADDR_LINKLOCAL(&nexthop->gate.ipv6)) {
ifp = if_lookup_by_index(nexthop->ifindex,
nexthop->vrf_id);
if (ifp && if_is_operative(ifp))
SET_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE);
else
UNSET_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE);
} else {
if (nexthop_active(AFI_IP6, re, nexthop, rn))
SET_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE);
else
UNSET_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE);
}

if (nexthop_active(AFI_IP6, nexthop, &rn->p, re->type,
re->flags, &mtu))
SET_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE);
else
UNSET_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE);
break;
case NEXTHOP_TYPE_BLACKHOLE:
SET_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE);
Expand All @@ -2194,13 +2229,27 @@ static unsigned nexthop_active_check(struct route_node *rn,
break;
}

skip_check:

if (!CHECK_FLAG(nexthop->flags, NEXTHOP_FLAG_ACTIVE)) {
if (IS_ZEBRA_DEBUG_RIB_DETAILED)
zlog_debug(" %s: Unable to find active nexthop",
__func__);
return 0;
}

/* Capture recursive nexthop mtu.
* TODO -- the code used to just reset the re's value to zero
* for each nexthop, and then jam any resolving route's mtu value in,
* whether or not that was zero, or lt/gt any existing value? The
* way this is used appears to be as a floor value, so let's try
* using it that way here.
*/
if (mtu > 0) {
if (re->nexthop_mtu == 0 || re->nexthop_mtu > mtu)
re->nexthop_mtu = mtu;
}

/* XXX: What exactly do those checks do? Do we support
* e.g. IPv4 routes with IPv6 nexthops or vice versa?
*/
Expand All @@ -2214,7 +2263,7 @@ static unsigned nexthop_active_check(struct route_node *rn,
* Possibly it may be better to use only the rib_table_info
* in every case.
*/
if (!family) {
if (family == 0) {
struct rib_table_info *info;

info = srcdest_rnode_table_info(rn);
Expand Down Expand Up @@ -2292,6 +2341,9 @@ static uint32_t nexthop_list_active_update(struct route_node *rn,

nexthop = nhg->nexthop;

/* Init recursive nh mtu */
re->nexthop_mtu = 0;

/* Process nexthops one-by-one */
for ( ; nexthop; nexthop = nexthop->next) {

Expand Down
3 changes: 2 additions & 1 deletion zebra/zebra_nhg.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -180,8 +180,9 @@ struct nhg_ctx {

vrf_id_t vrf_id;
afi_t afi;

/*
* This should only every be ZEBRA_ROUTE_NHG unless we get a a kernel
* This should only ever be ZEBRA_ROUTE_NHG unless we get a a kernel
* created nexthop not made by us.
*/
int type;
Expand Down

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