Broker configuration

[nirs]

Support multiple networks based on the config file.

Configuration flow

• search current configs for used subnet
  e.g. jq .subnet < /etc/vmnet-broker.d/*.json
• create network config file
• stat vm using network name
• delete the file to remove the network

Implementation notes

• read config on every request if the config changed since last read

  • restart to update config is not possible, delete current networks and break the network if clients are using it.
  • compare file stat (inode, size, timestamp)

• log error for invalid config

  • return VMNET_BROKER_NOT_FOUND to client since there is no such config

• Single file per network

  • need to read single file per request
  • easier for 3rd party applications - use drop-in files

• How to handle conflicting networks

  • different name, same config
  • overlapping subnet (e.g. 192.168.1.1/24, 192.168.1.1/28)
  • first used network win, next network will fail in vment_network_create

• format: json or plist? both?

• cache networks in CFDictionary

Network state

struct network_state {
    const char    *name;
    struct version {
        struct timespec  st_mtimespec;
        ino_t            st_ino;
        off_t            st_size;
    };
    
    vmnet_mode_t  mode;
    const char    *subnet;
    const char    *mask;
    const char    ipv6_prefix;
    int           prefix_len;

    vmnet_network_ref     ref;
    xpc_object_t          serialization;
    uint64_t              refcount;
};

Possible director layout

/etc/
    vmnet-broker.d/
        shared.json
        host.json
        ...