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isisd: fix crash when configuring the circuit type for the interface.

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1. When both Router A and Router B are configured with "is-type level-1," the area->is_type will be assigned the value IS_LEVEL_1, and circuit->is_type will also be assigned the value IS_LEVEL_1.
2. Configuring the circuit type "isis circuit-type level-1-2" for the interface of Router A will inadvertently call lib_interface_isis_circuit_type_modify to assign circuit->is_type the value IS_LEVEL_1_AND_2. This causes the hello packets reception and transmission, as well as the reception of LSP/SNP packets, to check circuit->is_type, allowing the level-2 hello packets to be sent and received normally, and level-2 LSP/SNP packets to be received normally.
3. When Router B modifies the configuration to "is-type level-2," and Router A and Router B establish a level-2 neighbor relationship, Router B sends level-2 LSP packets to Router A. Upon receiving these, Router A calls isis_spf_schedule to calculate the level-2 SPT, which results in accessing a null pointer.
When defining the behavior of the ISIS router, the call to isis_area_is_type_set will check that area->is_type is not IS_LEVEL_1_AND_2, and it disallows circuit->is_type_config from overriding circuit->is_type. Therefore, when configuring the circuit type for the interface of Router A, it should also check that area->is_type is not IS_LEVEL_1_AND_2 and disallow circuit->is_type_config from overriding circuit->is_type.

Signed-off-by: zhou-run <166502045+zhou-run@users.noreply.github.com>
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zhou-run 2024-05-18 11:13:35 +08:00 committed by GitHub
parent e41b4a755e
commit fdcd6749a2
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1 changed files with 2 additions and 1 deletions
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isisd/isis_nb_config.c
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@ -3821,7 +3821,8 @@ int lib_interface_isis_circuit_type_modify(struct nb_cb_modify_args *args)
case NB_EV_APPLY:
circuit = nb_running_get_entry(args->dnode, NULL, true);
circuit->is_type_config = circ_type;
isis_circuit_is_type_set(circuit, circ_type);
if (!circuit->area || circuit->area->is_type == IS_LEVEL_1_AND_2)
isis_circuit_is_type_set(circuit, circ_type);
break;
}