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[fgnhgorch] Enable packet flow when no FG ECMP neighbors are resolved (…
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…#1900)

*Added ability to set the FG route's next-hop as the RIF, the packets will trap to the kernel and be neighbor resolved via the kernel. Further, added the ability to set the next-hop to a fine grained ECMP next-hop after the 1st neighbor resolution occurs.
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@anish-n
anish-n authored Sep 15, 2021
1 parent 8cf355d commit d01524d
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Showing 4 changed files with 226 additions and 66 deletions.
243 changes: 185 additions & 58 deletions orchagent/fgnhgorch.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -317,6 +317,7 @@ bool FgNhgOrch::createFineGrainedNextHopGroup(FGNextHopGroupEntry &syncd_fg_rout
bool FgNhgOrch::removeFineGrainedNextHopGroup(FGNextHopGroupEntry *syncd_fg_route_entry)
{
SWSS_LOG_ENTER();

sai_status_t status;

for (auto nhgm : syncd_fg_route_entry->nhopgroup_members)
Expand All @@ -337,6 +338,34 @@ bool FgNhgOrch::removeFineGrainedNextHopGroup(FGNextHopGroupEntry *syncd_fg_rout

if (!gRouteOrch->removeFineGrainedNextHopGroup(syncd_fg_route_entry->next_hop_group_id))
{
SWSS_LOG_ERROR("Failed to remove nhgid %" PRIx64 " return failure",
syncd_fg_route_entry->next_hop_group_id);
return false;
}

return true;
}


bool FgNhgOrch::modifyRoutesNextHopId(sai_object_id_t vrf_id, const IpPrefix &ipPrefix, sai_object_id_t next_hop_id)
{
SWSS_LOG_ENTER();

sai_route_entry_t route_entry;
sai_attribute_t route_attr;

route_entry.vr_id = vrf_id;
route_entry.switch_id = gSwitchId;
copy(route_entry.destination, ipPrefix);

route_attr.id = SAI_ROUTE_ENTRY_ATTR_NEXT_HOP_ID;
route_attr.value.oid = next_hop_id;

sai_status_t status = sai_route_api->set_route_entry_attribute(&route_entry, &route_attr);
if (status != SAI_STATUS_SUCCESS)
{
SWSS_LOG_ERROR("Failed to set route %s with packet action forward, %d",
ipPrefix.to_string().c_str(), status);
return false;
}

Expand Down Expand Up @@ -385,22 +414,56 @@ bool FgNhgOrch::validNextHopInNextHopGroup(const NextHopKey& nexthop)
return true;
}

for (auto active_nh : syncd_fg_route_entry->active_nexthops)
if (fgNhgEntry->hash_bucket_indices.size() == 0 && syncd_fg_route_entry->points_to_rif)
{
bank_member_changes[fgNhgEntry->next_hops[active_nh.ip_address].bank].
active_nhs.push_back(active_nh);
/* Only happens the 1st time when hash_bucket_indices are not inited
*/
for (auto it : fgNhgEntry->next_hops)
{
while (bank_member_changes.size() <= it.second.bank)
{
bank_member_changes.push_back(BankMemberChanges());
}
}
}

bank_member_changes[fgNhgEntry->next_hops[nexthop.ip_address].bank].
nhs_to_add.push_back(nexthop);
nhopgroup_members_set[nexthop] = m_neighOrch->getNextHopId(nexthop);

if (!computeAndSetHashBucketChanges(syncd_fg_route_entry, fgNhgEntry,
bank_member_changes, nhopgroup_members_set, route_table.first))
if (syncd_fg_route_entry->points_to_rif)
{
SWSS_LOG_ERROR("Failed to set fine grained next hop %s",
nexthop.to_string().c_str());
return false;
// RIF route is now neigh resolved: create Fine Grained ECMP
if (!createFineGrainedNextHopGroup(*syncd_fg_route_entry, fgNhgEntry, syncd_fg_route_entry->nhg_key))
{
return false;
}

if (!setNewNhgMembers(*syncd_fg_route_entry, fgNhgEntry, bank_member_changes, nhopgroup_members_set, route_table.first))
{
return false;
}

if (!modifyRoutesNextHopId(route_tables.first, route_table.first, syncd_fg_route_entry->next_hop_group_id))
{
return false;
}
}
else
{
for (auto active_nh : syncd_fg_route_entry->active_nexthops)
{
bank_member_changes[fgNhgEntry->next_hops[active_nh.ip_address].bank].
active_nhs.push_back(active_nh);
}

if (!computeAndSetHashBucketChanges(syncd_fg_route_entry, fgNhgEntry,
bank_member_changes, nhopgroup_members_set, route_table.first))
{
SWSS_LOG_ERROR("Failed to set fine grained next hop %s",
nexthop.to_string().c_str());
return false;
}
}

m_neighOrch->increaseNextHopRefCount(nexthop);
Expand Down Expand Up @@ -760,14 +823,46 @@ bool FgNhgOrch::setInactiveBankToNextAvailableActiveBank(FGNextHopGroupEntry *sy

if (new_bank_idx == bank_member_changes.size())
{
SWSS_LOG_NOTICE("All banks of FG next-hops are down for prefix %s",
ipPrefix.to_string().c_str());
/* Case where there are no active banks */
/* Note: There is no way to set a NULL OID to the now inactive next-hops
* so we leave the next-hops as is in SAI, and future route/neighbor changes
* will take care of setting the next-hops to the correctly active nhs
SWSS_LOG_NOTICE("All banks of FG next-hops are down for prefix %s",
ipPrefix.to_string().c_str());

/* This may occur when there are no neigh entries available any more
* set route pointing to rif to allow for neigh resolution in kernel.
* If route already points to rif then we are done.
*/
syncd_fg_route_entry->syncd_fgnhg_map[bank].clear();
if (!syncd_fg_route_entry->points_to_rif)
{
std::string interface_alias = syncd_fg_route_entry->nhg_key.getNextHops().begin()->alias;
sai_object_id_t rif_next_hop_id = m_intfsOrch->getRouterIntfsId(interface_alias);
if (rif_next_hop_id == SAI_NULL_OBJECT_ID)
{
SWSS_LOG_INFO("Failed to get rif next hop for %s", interface_alias.c_str());
return false;
}
if (!modifyRoutesNextHopId(gVirtualRouterId, ipPrefix, rif_next_hop_id))
{
SWSS_LOG_ERROR("Failed to modify route nexthopid to rif");
return false;
}

if (!removeFineGrainedNextHopGroup(syncd_fg_route_entry))
{
SWSS_LOG_ERROR("Failed to delete Fine Grained next hop group");
return false;
}

syncd_fg_route_entry->points_to_rif = true;
syncd_fg_route_entry->next_hop_group_id = rif_next_hop_id;

// remove state_db entry
m_stateWarmRestartRouteTable.del(ipPrefix.to_string());
// Clear data structures
syncd_fg_route_entry->syncd_fgnhg_map.clear();
syncd_fg_route_entry->active_nexthops.clear();
syncd_fg_route_entry->inactive_to_active_map.clear();
syncd_fg_route_entry->nhopgroup_members.clear();
}
}

return true;
Expand Down Expand Up @@ -1017,6 +1112,7 @@ bool FgNhgOrch::setNewNhgMembers(FGNextHopGroupEntry &syncd_fg_route_entry, FgNh
{
m_recoveryMap.erase(nexthopsMap);
}
syncd_fg_route_entry.points_to_rif = false;

return true;
}
Expand Down Expand Up @@ -1094,13 +1190,13 @@ bool FgNhgOrch::syncdContainsFgNhg(sai_object_id_t vrf_id, const IpPrefix &ipPre


bool FgNhgOrch::setFgNhg(sai_object_id_t vrf_id, const IpPrefix &ipPrefix, const NextHopGroupKey &nextHops,
sai_object_id_t &next_hop_id, bool &prevNhgWasFineGrained)
sai_object_id_t &next_hop_id, bool &isNextHopIdChanged)
{
SWSS_LOG_ENTER();

/* default prevNhgWasFineGrained to true so that sai route is unaffected
/* default isNextHopIdChanged to false so that sai route is unaffected
* when we return early with success */
prevNhgWasFineGrained = true;
isNextHopIdChanged = false;
FgNhgEntry *fgNhgEntry = 0;
set<NextHopKey> next_hop_set = nextHops.getNextHops();
auto prefix_entry = m_fgNhgPrefixes.find(ipPrefix);
Expand All @@ -1123,7 +1219,7 @@ bool FgNhgOrch::setFgNhg(sai_object_id_t vrf_id, const IpPrefix &ipPrefix, const
break;
}
}

if (m_syncdFGRouteTables.find(vrf_id) != m_syncdFGRouteTables.end() &&
m_syncdFGRouteTables.at(vrf_id).find(ipPrefix) != m_syncdFGRouteTables.at(vrf_id).end() &&
m_syncdFGRouteTables.at(vrf_id).at(ipPrefix).nhg_key == nextHops)
Expand All @@ -1150,7 +1246,7 @@ bool FgNhgOrch::setFgNhg(sai_object_id_t vrf_id, const IpPrefix &ipPrefix, const
*/
for (auto it : fgNhgEntry->next_hops)
{
while(bank_member_changes.size() <= it.second.bank)
while (bank_member_changes.size() <= it.second.bank)
{
bank_member_changes.push_back(BankMemberChanges());
}
Expand Down Expand Up @@ -1202,6 +1298,7 @@ bool FgNhgOrch::setFgNhg(sai_object_id_t vrf_id, const IpPrefix &ipPrefix, const
{
bank_member_changes[fgNhgEntry->next_hops[nhk.ip_address].bank].
nhs_to_add.push_back(nhk);
next_hop_to_add = true;
}
}

Expand All @@ -1211,54 +1308,81 @@ bool FgNhgOrch::setFgNhg(sai_object_id_t vrf_id, const IpPrefix &ipPrefix, const

if (syncd_fg_route_entry_it != m_syncdFGRouteTables.at(vrf_id).end())
{
/* Route exists and nh was associated in the past */
FGNextHopGroupEntry *syncd_fg_route_entry = &(syncd_fg_route_entry_it->second);
/* Route exists, update FG ECMP group in SAI */
for (auto nhk : syncd_fg_route_entry->active_nexthops)

if (syncd_fg_route_entry->points_to_rif)
{
if (nhopgroup_members_set.find(nhk) == nhopgroup_members_set.end())
if (next_hop_to_add)
{
bank_member_changes[fgNhgEntry->next_hops[nhk.ip_address].bank].
nhs_to_del.push_back(nhk);
isNextHopIdChanged = true;
if (!createFineGrainedNextHopGroup(*syncd_fg_route_entry, fgNhgEntry, nextHops))
{
return false;
}

if (!setNewNhgMembers(*syncd_fg_route_entry, fgNhgEntry, bank_member_changes, nhopgroup_members_set, ipPrefix))
{
return false;
}
}
else
}
else
{
/* Update FG ECMP group in SAI */
for (auto nhk : syncd_fg_route_entry->active_nexthops)
{
bank_member_changes[fgNhgEntry->next_hops[nhk.ip_address].bank].
active_nhs.push_back(nhk);
if (nhopgroup_members_set.find(nhk) == nhopgroup_members_set.end())
{
bank_member_changes[fgNhgEntry->next_hops[nhk.ip_address].bank].
nhs_to_del.push_back(nhk);
}
else
{
bank_member_changes[fgNhgEntry->next_hops[nhk.ip_address].bank].
active_nhs.push_back(nhk);
}
}
}

if (!computeAndSetHashBucketChanges(syncd_fg_route_entry, fgNhgEntry, bank_member_changes,
nhopgroup_members_set, ipPrefix))
{
return false;
if (!computeAndSetHashBucketChanges(syncd_fg_route_entry, fgNhgEntry, bank_member_changes,
nhopgroup_members_set, ipPrefix))
{
return false;
}
}
}
else
{
/* New route + nhg addition */
prevNhgWasFineGrained = false;
if (next_hop_to_add == false)
{
SWSS_LOG_INFO("There were no valid next-hops to add %s:%s", ipPrefix.to_string().c_str(),
nextHops.to_string().c_str());
/* Let the route retry logic(upon false rc) take care of this case */
return false;
}

isNextHopIdChanged = true;
FGNextHopGroupEntry syncd_fg_route_entry;
if (!createFineGrainedNextHopGroup(syncd_fg_route_entry, fgNhgEntry, nextHops))
if (next_hop_to_add)
{
return false;
}
if (!createFineGrainedNextHopGroup(syncd_fg_route_entry, fgNhgEntry, nextHops))
{
return false;
}

if (!setNewNhgMembers(syncd_fg_route_entry, fgNhgEntry, bank_member_changes, nhopgroup_members_set, ipPrefix))
if (!setNewNhgMembers(syncd_fg_route_entry, fgNhgEntry, bank_member_changes, nhopgroup_members_set, ipPrefix))
{
return false;
}
}
else
{
return false;
sai_object_id_t rif_next_hop_id = m_intfsOrch->getRouterIntfsId(next_hop_set.begin()->alias);
if (rif_next_hop_id == SAI_NULL_OBJECT_ID)
{
SWSS_LOG_INFO("Failed to get rif next hop %s for %s",
nextHops.to_string().c_str(), ipPrefix.to_string().c_str());
return false;
}

syncd_fg_route_entry.next_hop_group_id = rif_next_hop_id;
syncd_fg_route_entry.points_to_rif = true;
}

m_syncdFGRouteTables[vrf_id][ipPrefix] = syncd_fg_route_entry;

SWSS_LOG_NOTICE("Created route %s:%s", ipPrefix.to_string().c_str(), nextHops.to_string().c_str());
}
m_syncdFGRouteTables[vrf_id][ipPrefix].nhg_key = nextHops;

Expand Down Expand Up @@ -1310,19 +1434,22 @@ bool FgNhgOrch::removeFgNhg(sai_object_id_t vrf_id, const IpPrefix &ipPrefix)
}

FGNextHopGroupEntry *syncd_fg_route_entry = &(it_route->second);
if (!removeFineGrainedNextHopGroup(syncd_fg_route_entry))
if (!syncd_fg_route_entry->points_to_rif)
{
SWSS_LOG_ERROR("Failed to clean-up fine grained ECMP SAI group");
return false;
}
if (!removeFineGrainedNextHopGroup(syncd_fg_route_entry))
{
SWSS_LOG_ERROR("Failed to clean-up fine grained ECMP SAI group");
return false;
}

for (auto nh : syncd_fg_route_entry->active_nexthops)
{
m_neighOrch->decreaseNextHopRefCount(nh);
}
for (auto nh : syncd_fg_route_entry->active_nexthops)
{
m_neighOrch->decreaseNextHopRefCount(nh);
}

// remove state_db entry
m_stateWarmRestartRouteTable.del(ipPrefix.to_string());
// remove state_db entry
m_stateWarmRestartRouteTable.del(ipPrefix.to_string());
}

it_route_table->second.erase(it_route);
if (it_route_table->second.size() == 0)
Expand Down
5 changes: 3 additions & 2 deletions orchagent/fgnhgorch.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -30,6 +30,7 @@ struct FGNextHopGroupEntry
BankFGNextHopGroupMap syncd_fgnhg_map; // Map of (bank) -> (nexthops) -> (index in nhopgroup_members)
NextHopGroupKey nhg_key; // Full next hop group key
InactiveBankMapsToBank inactive_to_active_map; // Maps an inactive bank to an active one in terms of hash bkts
bool points_to_rif; // Flag to identify that route is currently pointing to a rif
};

struct FGNextHopInfo
Expand Down Expand Up @@ -104,7 +105,7 @@ class FgNhgOrch : public Orch, public Observer
bool syncdContainsFgNhg(sai_object_id_t vrf_id, const IpPrefix &ipPrefix);
bool validNextHopInNextHopGroup(const NextHopKey&);
bool invalidNextHopInNextHopGroup(const NextHopKey&);
bool setFgNhg(sai_object_id_t vrf_id, const IpPrefix &ipPrefix, const NextHopGroupKey &nextHops, sai_object_id_t &next_hop_id, bool &prevNhgWasFineGrained);
bool setFgNhg(sai_object_id_t vrf_id, const IpPrefix &ipPrefix, const NextHopGroupKey &nextHops, sai_object_id_t &next_hop_id, bool &isNextHopIdChanged);
bool removeFgNhg(sai_object_id_t vrf_id, const IpPrefix &ipPrefix);

// warm reboot support
Expand Down Expand Up @@ -150,10 +151,10 @@ class FgNhgOrch : public Orch, public Observer
void setStateDbRouteEntry(const IpPrefix&, uint32_t index, NextHopKey nextHop);
bool writeHashBucketChange(FGNextHopGroupEntry *syncd_fg_route_entry, uint32_t index, sai_object_id_t nh_oid,
const IpPrefix &ipPrefix, NextHopKey nextHop);
bool modifyRoutesNextHopId(sai_object_id_t vrf_id, const IpPrefix &ipPrefix, sai_object_id_t next_hop_id);
bool createFineGrainedNextHopGroup(FGNextHopGroupEntry &syncd_fg_route_entry, FgNhgEntry *fgNhgEntry,
const NextHopGroupKey &nextHops);
bool removeFineGrainedNextHopGroup(FGNextHopGroupEntry *syncd_fg_route_entry);

vector<FieldValueTuple> generateRouteTableFromNhgKey(NextHopGroupKey nhg);
void cleanupIpInLinkToIpMap(const string &link, const IpAddress &ip, FgNhgEntry &fgNhg_entry);

Expand Down
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