github.com/looshlee/beatles@v0.0.0-20220727174639-742810ab631c/pkg/maps/policymap/callmap.go (about)

     1  // Copyright 2018-2019 Authors of Cilium
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package policymap
    16  
    17  import (
    18  	"fmt"
    19  	"unsafe"
    20  
    21  	"github.com/cilium/cilium/pkg/bpf"
    22  )
    23  
    24  // PolicyPlumbingMap maps endpoint IDs to the fd for the program which
    25  // implements its policy.
    26  type PolicyPlumbingMap struct {
    27  	*bpf.Map
    28  }
    29  
    30  // +k8s:deepcopy-gen=true
    31  // +k8s:deepcopy-gen:interfaces=github.com/cilium/cilium/pkg/bpf.MapKey
    32  type PlumbingKey struct {
    33  	key uint32
    34  }
    35  
    36  // +k8s:deepcopy-gen=true
    37  // +k8s:deepcopy-gen:interfaces=github.com/cilium/cilium/pkg/bpf.MapValue
    38  type PlumbingValue struct {
    39  	fd uint32
    40  }
    41  
    42  func (k *PlumbingKey) GetKeyPtr() unsafe.Pointer { return unsafe.Pointer(k) }
    43  func (k *PlumbingKey) NewValue() bpf.MapValue    { return &PlumbingValue{} }
    44  
    45  func (k *PlumbingKey) String() string {
    46  	return fmt.Sprintf("Endpoint: %d", k.key)
    47  }
    48  
    49  func (v *PlumbingValue) GetValuePtr() unsafe.Pointer { return unsafe.Pointer(v) }
    50  
    51  func (v *PlumbingValue) String() string {
    52  	return fmt.Sprintf("fd: %d", v.fd)
    53  }
    54  
    55  // RemoveGlobalMapping removes the mapping from the specified endpoint ID to
    56  // the BPF policy program for that endpoint.
    57  func RemoveGlobalMapping(id uint32) error {
    58  	gpm, err := OpenCallMap()
    59  	if err == nil {
    60  		k := PlumbingKey{
    61  			key: id,
    62  		}
    63  		err = gpm.Map.Delete(&k)
    64  		gpm.Close()
    65  	}
    66  
    67  	return err
    68  }
    69  
    70  // OpenCallMap opens the map that maps endpoint IDs to program file
    71  // descriptors, which allows tail calling into the policy datapath code from
    72  // other BPF programs.
    73  func OpenCallMap() (*PolicyPlumbingMap, error) {
    74  	m, err := bpf.OpenMap(CallMapName)
    75  	if err != nil {
    76  		return nil, err
    77  	}
    78  	m.MapKey = &PlumbingKey{}
    79  	m.MapValue = &PlumbingValue{}
    80  	return &PolicyPlumbingMap{Map: m}, nil
    81  }
    82  
    83  // CallString returns the string which indicates the calls map by index in the
    84  // ELF, and index into that call map for a specific endpoint.
    85  //
    86  // Derived from __section_tail(CILIUM_MAP_CALLS, NAME) per bpf/lib/tailcall.h.
    87  func CallString(id uint16) string {
    88  	return fmt.Sprintf("1/%#04x", id)
    89  }