BPF Syscall BPF_LINK_GET_FD_BY_ID command
This syscall command is used to get a file descriptor to an already loaded link via its unique identifier.
Return type
This command will return the file descriptor of the link (positive integer) or an error number (negative integer) if something went wrong.
Usage
This command is used to get a file descriptor to link so that you might use it in other syscall commands. This mechanism is usually used by inspection tools in combination with the BPF_OBJ_GET_INFO_BY_FD.
Attributes
link_id
This field holds the unique identifier of the link for which a file descriptor should be opened.