github.com/dylandreimerink/gobpfld@v0.6.1-0.20220205171531-e79c330ad608/map_queue.go (about)

     1  package gobpfld
     2  
     3  import (
     4  	"fmt"
     5  
     6  	"github.com/dylandreimerink/gobpfld/bpfsys"
     7  	"github.com/dylandreimerink/gobpfld/bpftypes"
     8  )
     9  
    10  var _ BPFMap = (*QueueMap)(nil)
    11  
    12  // QueueMap is a specialized map type, it has no key type, only a value type. It works like any other FIFO queue.
    13  type QueueMap struct {
    14  	AbstractMap
    15  }
    16  
    17  func (m *QueueMap) Load() error {
    18  	if m.Definition.Type != bpftypes.BPF_MAP_TYPE_QUEUE {
    19  		return fmt.Errorf("map type in definition must be BPF_MAP_TYPE_QUEUE when using an QueueMap")
    20  	}
    21  
    22  	err := m.load(nil)
    23  	if err != nil {
    24  		return err
    25  	}
    26  
    27  	err = mapRegister.add(m)
    28  	if err != nil {
    29  		return fmt.Errorf("map register: %w", err)
    30  	}
    31  
    32  	return nil
    33  }
    34  
    35  // Close closes the file descriptor associate with the map, this will cause the map to unload from the kernel
    36  // if it is not still in use by a eBPF program, bpf FS, or a userspace program still holding a fd to the map.
    37  func (m *QueueMap) Close() error {
    38  	err := mapRegister.delete(m)
    39  	if err != nil {
    40  		return fmt.Errorf("map register: %w", err)
    41  	}
    42  
    43  	return m.close()
    44  }
    45  
    46  // Enqueue enqueues a new value
    47  func (m *QueueMap) Enqueue(value interface{}) error {
    48  	return m.set(nil, value, bpfsys.BPFMapElemAny)
    49  }
    50  
    51  // Peek peeks at the first value in the queue without removing it.
    52  func (m *QueueMap) Peek(value interface{}) error {
    53  	return m.get(nil, value)
    54  }
    55  
    56  // Dequeue returns the value of the from of the queue, removing it in the process.
    57  func (m *QueueMap) Dequeue(value interface{}) error {
    58  	return m.lookupAndDelete(nil, value, bpfsys.BPFMapElemAny)
    59  }
    60  
    61  // Iterator returns a map iterator which can be used to loop over all values of the map.
    62  // Looping over the queue will consume all values.
    63  func (m *QueueMap) Iterator() MapIterator {
    64  	return &lookupAndDeleteIterator{
    65  		BPFMap: m,
    66  	}
    67  }