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block.go
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block.go
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package block
import (
"bytes"
"encoding/hex"
"github.com/zalando/skipper/filters"
skpio "github.com/zalando/skipper/io"
"github.com/zalando/skipper/metrics"
)
type blockSpec struct {
MaxMatcherBufferSize uint64
hex bool
}
type toBlockKeys struct{ Str []byte }
func (b toBlockKeys) String() string {
return string(b.Str)
}
type block struct {
toblockList []toBlockKeys
maxEditorBuffer uint64
maxBufferHandling skpio.MaxBufferHandling
metrics metrics.Metrics
}
// NewBlockFilter *deprecated* version of NewBlock
func NewBlockFilter(maxMatcherBufferSize uint64) filters.Spec {
return NewBlock(maxMatcherBufferSize)
}
func NewBlock(maxMatcherBufferSize uint64) filters.Spec {
return &blockSpec{
MaxMatcherBufferSize: maxMatcherBufferSize,
}
}
func NewBlockHex(maxMatcherBufferSize uint64) filters.Spec {
return &blockSpec{
MaxMatcherBufferSize: maxMatcherBufferSize,
hex: true,
}
}
func (bs *blockSpec) Name() string {
if bs.hex {
return filters.BlockHexName
}
return filters.BlockName
}
func (bs *blockSpec) CreateFilter(args []interface{}) (filters.Filter, error) {
if len(args) == 0 {
return nil, filters.ErrInvalidFilterParameters
}
sargs := make([]toBlockKeys, 0, len(args))
for _, w := range args {
v, ok := w.(string)
if !ok {
return nil, filters.ErrInvalidFilterParameters
}
if bs.hex {
a, err := hex.DecodeString(v)
if err != nil {
return nil, err
}
sargs = append(sargs, toBlockKeys{Str: a})
} else {
sargs = append(sargs, toBlockKeys{Str: []byte(v)})
}
}
return &block{
toblockList: sargs,
maxBufferHandling: skpio.MaxBufferBestEffort,
maxEditorBuffer: bs.MaxMatcherBufferSize,
metrics: metrics.Default,
}, nil
}
func blockMatcher(m metrics.Metrics, matches []toBlockKeys) func(b []byte) (int, error) {
return func(b []byte) (int, error) {
for _, s := range matches {
s := s
if bytes.Contains(b, s.Str) {
m.IncCounter("blocked.requests")
return 0, skpio.ErrBlocked
}
}
return len(b), nil
}
}
func (b *block) Request(ctx filters.FilterContext) {
req := ctx.Request()
if req.ContentLength == 0 {
return
}
// fix filter chaining - https://github.com/zalando/skipper/issues/2605
ctx.Request().Header.Del("Content-Length")
ctx.Request().ContentLength = -1
req.Body = skpio.InspectReader(
req.Context(),
skpio.BufferOptions{
MaxBufferHandling: b.maxBufferHandling,
ReadBufferSize: b.maxEditorBuffer,
},
blockMatcher(b.metrics, b.toblockList),
req.Body)
}
func (*block) Response(filters.FilterContext) {}