osdep_eth_init() ("osdep" stands for "OS DEPendent") is called by eth_init() during the initialization of the network service. osdep_eth_init() calls several Minix-specific functions to initialize several Minix-independent and Minix-dependent ethernet port fields (for example, the ethernet address is obtained by querying from the ethernet driver).
After each ethernet port is configured, sr_add_minor() and setup_read() are called for the port.