SwitchState: MySid FRR backup next-hop-set fields

Summary:
SwitchState schema for SRv6 midpoint FRR. Add to `MySidFields` and expose via `MySid` accessors:

- `backupResolvedNextHopsId`: the resolved backup (standby) next-hop set id.
- `backupUnresolveNextHopsId`: the requested (unresolved) backup set id set by the addAdjacencyFrr thrift API; the RIB resolves it into `backupResolvedNextHopsId`, symmetric to `unresolveNextHopsId` -> `resolvedNextHopsId` for the primary.
- `monitoredAggPortId`: the LAG the HW protection group monitors for failover.

Additive schema change, no behavior. Regenerated `fsdb_model_thriftpath.h` (generated).

Unit test: `MySidTest.BackupAndMonitoredAggAccessors` round-trips the new backup/monitored accessors (set / get / reset).

Foundation of the SRv6 midpoint FRR stack (diffs 1/8..8/8); additive and dormant until the SAI / RIB / thrift / observer diffs above it are in effect.

Reviewed By: jasmeetbagga

Differential Revision: D110984229

fbshipit-source-id: e39e1e1cdb0e28862d70433036de0780793a5928

Author: vasantspatil

fboss/agent/state/MySid.h

@@ -128,6 +128,38 @@ class MySid : public ThriftStructNode<MySid, state::MySidFields> {
     }
   }
 
+  std::optional<NextHopSetID> getBackupResolvedNextHopsId() const {
+    if (auto id = safe_cref<switch_state_tags::backupResolvedNextHopsId>()) {
+      return NextHopSetID(id->cref());
+    }
+    return std::nullopt;
+  }
+
+  void setBackupResolvedNextHopsId(std::optional<NextHopSetID> id) {
+    if (id) {
+      set<switch_state_tags::backupResolvedNextHopsId>(
+          static_cast<int64_t>(*id));
+    } else {
+      ref<switch_state_tags::backupResolvedNextHopsId>().reset();
+    }
+  }
+
+  std::optional<NextHopSetID> getBackupUnresolveNextHopsId() const {
+    if (auto id = safe_cref<switch_state_tags::backupUnresolveNextHopsId>()) {
+      return NextHopSetID(id->cref());
+    }
+    return std::nullopt;
+  }
+
+  void setBackupUnresolveNextHopsId(std::optional<NextHopSetID> id) {
+    if (id) {
+      set<switch_state_tags::backupUnresolveNextHopsId>(
+          static_cast<int64_t>(*id));
+    } else {
+      ref<switch_state_tags::backupUnresolveNextHopsId>().reset();
+    }
+  }
+
  private:
   // Inherit the constructors required for clone()
   using Base::Base;

fboss/agent/state/tests/MySidTests.cpp

@@ -363,3 +363,26 @@ TEST(MySidDeltaTest, MixedAddRemoveChange) {
   EXPECT_EQ(removed, (std::set<std::string>{"fc00:100::1/48"}));
   EXPECT_EQ(changed, (std::set<std::string>{"fc00:200::1/64"}));
 }
+
+// SRv6 midpoint FRR: the backup next-hop-set ids are optional and must
+// round-trip through the MySid node accessors.
+TEST(MySidTest, BackupAccessors) {
+  auto mySid = makeMySid();
+  // Unset by default.
+  EXPECT_FALSE(mySid->getBackupResolvedNextHopsId().has_value());
+  EXPECT_FALSE(mySid->getBackupUnresolveNextHopsId().has_value());
+
+  // Set and read back.
+  mySid->setBackupUnresolveNextHopsId(NextHopSetID(1234));
+  mySid->setBackupResolvedNextHopsId(NextHopSetID(5678));
+  ASSERT_TRUE(mySid->getBackupUnresolveNextHopsId().has_value());
+  EXPECT_EQ(*mySid->getBackupUnresolveNextHopsId(), NextHopSetID(1234));
+  ASSERT_TRUE(mySid->getBackupResolvedNextHopsId().has_value());
+  EXPECT_EQ(*mySid->getBackupResolvedNextHopsId(), NextHopSetID(5678));
+
+  // Reset back to unset.
+  mySid->setBackupUnresolveNextHopsId(std::nullopt);
+  mySid->setBackupResolvedNextHopsId(std::nullopt);
+  EXPECT_FALSE(mySid->getBackupUnresolveNextHopsId().has_value());
+  EXPECT_FALSE(mySid->getBackupResolvedNextHopsId().has_value());
+}

fboss/agent/switch_state.thrift

@@ -689,6 +689,16 @@ struct MySidFields {
   7: optional bool isV6;
   # Optional named next hop group for the MySid entry.
   8: optional string namedNextHopGroup;
+  # SRv6 midpoint FRR: when set, this MySid entry is programmed as a hardware
+  # protection group. resolvedNextHopsId (field 4) is the PRIMARY path; this is
+  # the resolved BACKUP (standby) next hop set id (typically an ECMP of
+  # SRv6-encap next hops that impose a repair SID).
+  9: optional i64 backupResolvedNextHopsId;
+  # SRv6 midpoint FRR: the requested (unresolved) BACKUP next hop set id, set by
+  # the addAdjacencyFrr thrift API. RibMySidUpdater resolves it into
+  # backupResolvedNextHopsId (field 9), symmetric to unresolveNextHopsId
+  # (field 3) -> resolvedNextHopsId (field 4).
+  12: optional i64 backupUnresolveNextHopsId;
 }
 
 struct QosPolicyFields {

fboss/fsdb/if/oss/fsdb_model_thriftpath.h

@@ -7589,6 +7589,8 @@ class ChildThriftPath<::facebook::fboss::state::MySidFields, ::facebook::fboss::
     STRUCT_CHILD_GETTERS(clientId, 6);
     STRUCT_CHILD_GETTERS(isV6, 7);
     STRUCT_CHILD_GETTERS(namedNextHopGroup, 8);
+    STRUCT_CHILD_GETTERS(backupResolvedNextHopsId, 9);
+    STRUCT_CHILD_GETTERS(backupUnresolveNextHopsId, 12);
 };