Support arbitary bitwise register mask (#20)

For NXReg, OvS will accept value/mask on arbitary bitwise. If using
range[start:end], it is hard to combine discontinuous value/mask,
such as, to merge reg0[0:0] with reg0[2:2], with range method,
we will pass NXRange[0:2] and it will generate mask 0x7, but actually,
the mask is 0x5.

In this patch, we change merge function to support discontinuous mask
according to each reg piece range and then merge all pieces for one register.

Signed-off-by: Gao Jinjun <gjinjun@gmail.com>

VERSION

@@ -1 +1 @@
-v0.5.1
+v0.5.2

go.mod

@@ -3,7 +3,7 @@ module antrea.io/ofnet
 go 1.15
 
 require (
-	antrea.io/libOpenflow v0.6.0
+	antrea.io/libOpenflow v0.6.2
 	github.com/Microsoft/go-winio v0.4.14
 	github.com/cenkalti/hub v1.0.1-0.20140529221144-7be60e186e66 // indirect
 	github.com/cenkalti/rpc2 v0.0.0-20140912135055-44d0d95e4f52 // indirect

go.sum

@@ -1,5 +1,5 @@
-antrea.io/libOpenflow v0.6.0 h1:2QZUz5rt/1D1mIqbJALEqyQV4vdkybNB8vTBcG8TLS4=
-antrea.io/libOpenflow v0.6.0/go.mod h1:CzEJZxDNAupiGxeL5VOw92PsxfyvehEAvE3PiC6gr8o=
+antrea.io/libOpenflow v0.6.2 h1:1JMSJ7Lp7yOhKybHey9VDtRI6JuIgkhUWJBX5GIFY9I=
+antrea.io/libOpenflow v0.6.2/go.mod h1:CzEJZxDNAupiGxeL5VOw92PsxfyvehEAvE3PiC6gr8o=
 github.com/Microsoft/go-winio v0.4.14 h1:+hMXMk01us9KgxGb7ftKQt2Xpf5hH/yky+TDA+qxleU=
 github.com/Microsoft/go-winio v0.4.14/go.mod h1:qXqCSQ3Xa7+6tgxaGTIe4Kpcdsi+P8jBhyzoq1bpyYA=
 github.com/cenkalti/hub v1.0.1-0.20140529221144-7be60e186e66 h1:mqwgWF7yBJ/zOFlWZk84IRFG/FhMG0f7aZWvcTx/JHA=

ofctrl/fgraphFlow.go

@@ -151,17 +151,11 @@ type writeMetadata struct {
 // could be calculated according to range automatically
 type NXRegister struct {
 	ID    int                 // ID of NXM_NX_REG, value should be from 0 to 15
-	Data  uint32              // Data to cache in register
+	Data  uint32              // Data to cache in register. Note: Don't shift Data to its offset in caller
+	Mask  uint32              // Bitwise mask of data
 	Range *openflow13.NXRange // Range of bits in register
 }
 
-func (r *NXRegister) getShiftedValue() uint32 {
-	if r.Range == nil {
-		return r.Data
-	}
-	return r.Data << r.Range.GetOfs()
-}
-
 type XXRegister struct {
 	ID   int    // ID of NXM_NX_XXREG, value should be from 0 to 3
 	Data []byte // Data to cache in xxreg
@@ -426,7 +420,7 @@ func (self *Flow) xlateMatch() openflow13.Match {
 		}
 		for _, regs := range regMap {
 			reg := merge(regs)
-			regField := openflow13.NewRegMatchField(reg.ID, reg.Data, reg.Range)
+			regField := openflow13.NewRegMatchFieldWithMask(reg.ID, reg.Data, reg.Mask)
 			ofMatch.AddField(*regField)
 		}
 	}
@@ -610,27 +604,42 @@ func getRangeEnd(rng *openflow13.NXRange) uint16 {
 	return rng.GetOfs() + rng.GetNbits() - 1
 }
 
-func merge(regs []*NXRegister) *NXRegister {
-	if len(regs) == 1 {
-		return regs[0]
+func getStartFromMask(mask uint32) uint16 {
+	var count uint16
+
+	if mask == 0 {
+		return 0
+	}
+
+	for mask&1 == 0 {
+		mask >>= 1
+		count++
 	}
-	var data uint32
-	min := regs[0].Range.GetOfs()
-	max := getRangeEnd(regs[0].Range)
+	return count
+}
+
+func merge(regs []*NXRegister) *NXRegister {
+	var data, mask uint32
 	for _, reg := range regs {
-		data |= reg.Data << reg.Range.GetOfs()
-		end := getRangeEnd(reg.Range)
-		if reg.Range.GetOfs() < min {
-			min = reg.Range.GetOfs()
-		}
-		if end > max {
-			max = end
+		if reg.Mask != 0 {
+			data |= reg.Data << getStartFromMask(reg.Mask)
+			mask |= reg.Mask
+		} else if reg.Range != nil {
+			// no mask, need to compute mask according to range
+			end := getRangeEnd(reg.Range)
+			start := reg.Range.GetOfs()
+			data |= reg.Data << start
+			mask |= ((uint32(1) << (end - start + 1)) - 1) << start
+		} else {
+			// full range
+			data |= reg.Data
+			mask |= 0xffffffff
 		}
 	}
 	return &NXRegister{
-		ID:    regs[0].ID,
-		Data:  data,
-		Range: openflow13.NewNXRange(int(min), int(max)),
+		ID:   regs[0].ID,
+		Data: data,
+		Mask: mask,
 	}
 }
 

ofctrl/ofMatchFields.go

@@ -700,6 +700,7 @@ func getNXReg(mf *openflow13.MatchField) (*NXRegister, error) {
 		}
 		rng := getNXRangeFromUint32Mask(maskData)
 		reg.Range = rng
+		reg.Mask = maskData
 	}
 	return reg, nil
 }