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Diffstat (limited to 'vendor/github.com/google/gopacket/flows.go')
| -rw-r--r-- | vendor/github.com/google/gopacket/flows.go | 236 |
1 files changed, 0 insertions, 236 deletions
diff --git a/vendor/github.com/google/gopacket/flows.go b/vendor/github.com/google/gopacket/flows.go deleted file mode 100644 index 7203ead..0000000 --- a/vendor/github.com/google/gopacket/flows.go +++ /dev/null @@ -1,236 +0,0 @@ -// Copyright 2012 Google, Inc. All rights reserved. -// -// Use of this source code is governed by a BSD-style license -// that can be found in the LICENSE file in the root of the source -// tree. - -package gopacket - -import ( - "bytes" - "fmt" - "strconv" -) - -// MaxEndpointSize determines the maximum size in bytes of an endpoint address. -// -// Endpoints/Flows have a problem: They need to be hashable. Therefore, they -// can't use a byte slice. The two obvious choices are to use a string or a -// byte array. Strings work great, but string creation requires memory -// allocation, which can be slow. Arrays work great, but have a fixed size. We -// originally used the former, now we've switched to the latter. Use of a fixed -// byte-array doubles the speed of constructing a flow (due to not needing to -// allocate). This is a huge increase... too much for us to pass up. -// -// The end result of this, though, is that an endpoint/flow can't be created -// using more than MaxEndpointSize bytes per address. -const MaxEndpointSize = 16 - -// Endpoint is the set of bytes used to address packets at various layers. -// See LinkLayer, NetworkLayer, and TransportLayer specifications. -// Endpoints are usable as map keys. -type Endpoint struct { - typ EndpointType - len int - raw [MaxEndpointSize]byte -} - -// EndpointType returns the endpoint type associated with this endpoint. -func (a Endpoint) EndpointType() EndpointType { return a.typ } - -// Raw returns the raw bytes of this endpoint. These aren't human-readable -// most of the time, but they are faster than calling String. -func (a Endpoint) Raw() []byte { return a.raw[:a.len] } - -// LessThan provides a stable ordering for all endpoints. It sorts first based -// on the EndpointType of an endpoint, then based on the raw bytes of that -// endpoint. -// -// For some endpoints, the actual comparison may not make sense, however this -// ordering does provide useful information for most Endpoint types. -// Ordering is based first on endpoint type, then on raw endpoint bytes. -// Endpoint bytes are sorted lexigraphically. -func (a Endpoint) LessThan(b Endpoint) bool { - return a.typ < b.typ || (a.typ == b.typ && bytes.Compare(a.raw[:a.len], b.raw[:b.len]) < 0) -} - -// fnvHash is used by our FastHash functions, and implements the FNV hash -// created by Glenn Fowler, Landon Curt Noll, and Phong Vo. -// See http://isthe.com/chongo/tech/comp/fnv/. -func fnvHash(s []byte) (h uint64) { - h = fnvBasis - for i := 0; i < len(s); i++ { - h ^= uint64(s[i]) - h *= fnvPrime - } - return -} - -const fnvBasis = 14695981039346656037 -const fnvPrime = 1099511628211 - -// FastHash provides a quick hashing function for an endpoint, useful if you'd -// like to split up endpoints by modulos or other load-balancing techniques. -// It uses a variant of Fowler-Noll-Vo hashing. -// -// The output of FastHash is not guaranteed to remain the same through future -// code revisions, so should not be used to key values in persistent storage. -func (a Endpoint) FastHash() (h uint64) { - h = fnvHash(a.raw[:a.len]) - h ^= uint64(a.typ) - h *= fnvPrime - return -} - -// NewEndpoint creates a new Endpoint object. -// -// The size of raw must be less than MaxEndpointSize, otherwise this function -// will panic. -func NewEndpoint(typ EndpointType, raw []byte) (e Endpoint) { - e.len = len(raw) - if e.len > MaxEndpointSize { - panic("raw byte length greater than MaxEndpointSize") - } - e.typ = typ - copy(e.raw[:], raw) - return -} - -// EndpointTypeMetadata is used to register a new endpoint type. -type EndpointTypeMetadata struct { - // Name is the string returned by an EndpointType's String function. - Name string - // Formatter is called from an Endpoint's String function to format the raw - // bytes in an Endpoint into a human-readable string. - Formatter func([]byte) string -} - -// EndpointType is the type of a gopacket Endpoint. This type determines how -// the bytes stored in the endpoint should be interpreted. -type EndpointType int64 - -var endpointTypes = map[EndpointType]EndpointTypeMetadata{} - -// RegisterEndpointType creates a new EndpointType and registers it globally. -// It MUST be passed a unique number, or it will panic. Numbers 0-999 are -// reserved for gopacket's use. -func RegisterEndpointType(num int, meta EndpointTypeMetadata) EndpointType { - t := EndpointType(num) - if _, ok := endpointTypes[t]; ok { - panic("Endpoint type number already in use") - } - endpointTypes[t] = meta - return t -} - -func (e EndpointType) String() string { - if t, ok := endpointTypes[e]; ok { - return t.Name - } - return strconv.Itoa(int(e)) -} - -func (a Endpoint) String() string { - if t, ok := endpointTypes[a.typ]; ok && t.Formatter != nil { - return t.Formatter(a.raw[:a.len]) - } - return fmt.Sprintf("%v:%v", a.typ, a.raw) -} - -// Flow represents the direction of traffic for a packet layer, as a source and destination Endpoint. -// Flows are usable as map keys. -type Flow struct { - typ EndpointType - slen, dlen int - src, dst [MaxEndpointSize]byte -} - -// FlowFromEndpoints creates a new flow by pasting together two endpoints. -// The endpoints must have the same EndpointType, or this function will return -// an error. -func FlowFromEndpoints(src, dst Endpoint) (_ Flow, err error) { - if src.typ != dst.typ { - err = fmt.Errorf("Mismatched endpoint types: %v->%v", src.typ, dst.typ) - return - } - return Flow{src.typ, src.len, dst.len, src.raw, dst.raw}, nil -} - -// FastHash provides a quick hashing function for a flow, useful if you'd -// like to split up flows by modulos or other load-balancing techniques. -// It uses a variant of Fowler-Noll-Vo hashing, and is guaranteed to collide -// with its reverse flow. IE: the flow A->B will have the same hash as the flow -// B->A. -// -// The output of FastHash is not guaranteed to remain the same through future -// code revisions, so should not be used to key values in persistent storage. -func (f Flow) FastHash() (h uint64) { - // This combination must be commutative. We don't use ^, since that would - // give the same hash for all A->A flows. - h = fnvHash(f.src[:f.slen]) + fnvHash(f.dst[:f.dlen]) - h ^= uint64(f.typ) - h *= fnvPrime - return -} - -// String returns a human-readable representation of this flow, in the form -// "Src->Dst" -func (f Flow) String() string { - s, d := f.Endpoints() - return fmt.Sprintf("%v->%v", s, d) -} - -// EndpointType returns the EndpointType for this Flow. -func (f Flow) EndpointType() EndpointType { - return f.typ -} - -// Endpoints returns the two Endpoints for this flow. -func (f Flow) Endpoints() (src, dst Endpoint) { - return Endpoint{f.typ, f.slen, f.src}, Endpoint{f.typ, f.dlen, f.dst} -} - -// Src returns the source Endpoint for this flow. -func (f Flow) Src() (src Endpoint) { - src, _ = f.Endpoints() - return -} - -// Dst returns the destination Endpoint for this flow. -func (f Flow) Dst() (dst Endpoint) { - _, dst = f.Endpoints() - return -} - -// Reverse returns a new flow with endpoints reversed. -func (f Flow) Reverse() Flow { - return Flow{f.typ, f.dlen, f.slen, f.dst, f.src} -} - -// NewFlow creates a new flow. -// -// src and dst must have length <= MaxEndpointSize, otherwise NewFlow will -// panic. -func NewFlow(t EndpointType, src, dst []byte) (f Flow) { - f.slen = len(src) - f.dlen = len(dst) - if f.slen > MaxEndpointSize || f.dlen > MaxEndpointSize { - panic("flow raw byte length greater than MaxEndpointSize") - } - f.typ = t - copy(f.src[:], src) - copy(f.dst[:], dst) - return -} - -// EndpointInvalid is an endpoint type used for invalid endpoints, IE endpoints -// that are specified incorrectly during creation. -var EndpointInvalid = RegisterEndpointType(0, EndpointTypeMetadata{Name: "invalid", Formatter: func(b []byte) string { - return fmt.Sprintf("%v", b) -}}) - -// InvalidEndpoint is a singleton Endpoint of type EndpointInvalid. -var InvalidEndpoint = NewEndpoint(EndpointInvalid, nil) - -// InvalidFlow is a singleton Flow of type EndpointInvalid. -var InvalidFlow = NewFlow(EndpointInvalid, nil, nil) |