ntopng crashes when too many ZMQ interfaces are used

[lucaderi]

it should not crash but just report a limit was hit

#7 0x000000000040e79a in main(int, char**) (argc=, argv=) at src/main.cpp:194
(gdb) f 3
#3 0x00007ffff794af28 in zmq::epoll_t::epoll_t(zmq::ctx_t const&) () from /lib64/libzmq.so.5
(gdb) f
#3 0x00007ffff794af28 in zmq::epoll_t::epoll_t(zmq::ctx_t const&) () from /lib64/libzmq.so.5
(gdb) f 6
#6 0x0000000000471462 in ZMQCollectorInterface::ZMQCollectorInterface (this=0x62275b0, _endpoint=) at src/ZMQCollectorInterface.cpp:54
54 subscriber[num_subscribers].socket = zmq_socket(context, ZMQ_SUB);
(gdb) q
A debugging session is active.

[simonemainardi]

Crash was happening with 100 ZMQ intefaces.

After internal review, maximum number of ntopng interfaces has been reduced and the crash no longer occur (3159f49). This is also documented in https://www.ntop.org/guides/ntopng/faq.html#maximum-number-of-interfaces

Specifying more than the maximum number of interfaces causes exceeding interfaces to be ignored.