[feature] Inherit resource limits from cgroups (#1336)

When GTS is running in a container runtime which has configured CPU or
memory limits or under an init system that uses cgroups to impose CPU
and memory limits the values the Go runtime sees for GOMAXPROCS and
GOMEMLIMIT are still based on the host resources, not the cgroup.

At least for the throttling middlewares which use GOMAXPROCS to
configure their queue size, this can result in GTS running with values
too big compared to the resources that will actuall be available to it.

This introduces 2 dependencies which can pick up resource contraints
from the current cgroup and tune the Go runtime accordingly. This should
result in the different queues being appropriately sized and in general
more predictable performance. These dependencies are a no-op on
non-Linux systems or if running in a cgroup that doesn't set a limit on
CPU or memory.

The automatic tuning of GOMEMLIMIT can be disabled by either explicitly
setting GOMEMLIMIT yourself or by setting AUTOMEMLIMIT=off. The
automatic tuning of GOMAXPROCS can similarly be counteracted by setting
GOMAXPROCS yourself.

vendor/github.com/cilium/ebpf/asm/alu.go

@@ -0,0 +1,149 @@
+package asm
+
+//go:generate stringer -output alu_string.go -type=Source,Endianness,ALUOp
+
+// Source of ALU / ALU64 / Branch operations
+//
+//    msb      lsb
+//    +----+-+---+
+//    |op  |S|cls|
+//    +----+-+---+
+type Source uint8
+
+const sourceMask OpCode = 0x08
+
+// Source bitmask
+const (
+	// InvalidSource is returned by getters when invoked
+	// on non ALU / branch OpCodes.
+	InvalidSource Source = 0xff
+	// ImmSource src is from constant
+	ImmSource Source = 0x00
+	// RegSource src is from register
+	RegSource Source = 0x08
+)
+
+// The Endianness of a byte swap instruction.
+type Endianness uint8
+
+const endianMask = sourceMask
+
+// Endian flags
+const (
+	InvalidEndian Endianness = 0xff
+	// Convert to little endian
+	LE Endianness = 0x00
+	// Convert to big endian
+	BE Endianness = 0x08
+)
+
+// ALUOp are ALU / ALU64 operations
+//
+//    msb      lsb
+//    +----+-+---+
+//    |OP  |s|cls|
+//    +----+-+---+
+type ALUOp uint8
+
+const aluMask OpCode = 0xf0
+
+const (
+	// InvalidALUOp is returned by getters when invoked
+	// on non ALU OpCodes
+	InvalidALUOp ALUOp = 0xff
+	// Add - addition
+	Add ALUOp = 0x00
+	// Sub - subtraction
+	Sub ALUOp = 0x10
+	// Mul - multiplication
+	Mul ALUOp = 0x20
+	// Div - division
+	Div ALUOp = 0x30
+	// Or - bitwise or
+	Or ALUOp = 0x40
+	// And - bitwise and
+	And ALUOp = 0x50
+	// LSh - bitwise shift left
+	LSh ALUOp = 0x60
+	// RSh - bitwise shift right
+	RSh ALUOp = 0x70
+	// Neg - sign/unsign signing bit
+	Neg ALUOp = 0x80
+	// Mod - modulo
+	Mod ALUOp = 0x90
+	// Xor - bitwise xor
+	Xor ALUOp = 0xa0
+	// Mov - move value from one place to another
+	Mov ALUOp = 0xb0
+	// ArSh - arithmatic shift
+	ArSh ALUOp = 0xc0
+	// Swap - endian conversions
+	Swap ALUOp = 0xd0
+)
+
+// HostTo converts from host to another endianness.
+func HostTo(endian Endianness, dst Register, size Size) Instruction {
+	var imm int64
+	switch size {
+	case Half:
+		imm = 16
+	case Word:
+		imm = 32
+	case DWord:
+		imm = 64
+	default:
+		return Instruction{OpCode: InvalidOpCode}
+	}
+
+	return Instruction{
+		OpCode:   OpCode(ALUClass).SetALUOp(Swap).SetSource(Source(endian)),
+		Dst:      dst,
+		Constant: imm,
+	}
+}
+
+// Op returns the OpCode for an ALU operation with a given source.
+func (op ALUOp) Op(source Source) OpCode {
+	return OpCode(ALU64Class).SetALUOp(op).SetSource(source)
+}
+
+// Reg emits `dst (op) src`.
+func (op ALUOp) Reg(dst, src Register) Instruction {
+	return Instruction{
+		OpCode: op.Op(RegSource),
+		Dst:    dst,
+		Src:    src,
+	}
+}
+
+// Imm emits `dst (op) value`.
+func (op ALUOp) Imm(dst Register, value int32) Instruction {
+	return Instruction{
+		OpCode:   op.Op(ImmSource),
+		Dst:      dst,
+		Constant: int64(value),
+	}
+}
+
+// Op32 returns the OpCode for a 32-bit ALU operation with a given source.
+func (op ALUOp) Op32(source Source) OpCode {
+	return OpCode(ALUClass).SetALUOp(op).SetSource(source)
+}
+
+// Reg32 emits `dst (op) src`, zeroing the upper 32 bit of dst.
+func (op ALUOp) Reg32(dst, src Register) Instruction {
+	return Instruction{
+		OpCode: op.Op32(RegSource),
+		Dst:    dst,
+		Src:    src,
+	}
+}
+
+// Imm32 emits `dst (op) value`, zeroing the upper 32 bit of dst.
+func (op ALUOp) Imm32(dst Register, value int32) Instruction {
+	return Instruction{
+		OpCode:   op.Op32(ImmSource),
+		Dst:      dst,
+		Constant: int64(value),
+	}
+}

vendor/github.com/cilium/ebpf/asm/alu_string.go

@@ -0,0 +1,107 @@
+// Code generated by "stringer -output alu_string.go -type=Source,Endianness,ALUOp"; DO NOT EDIT.
+
+package asm
+
+import "strconv"
+
+func _() {
+	// An "invalid array index" compiler error signifies that the constant values have changed.
+	// Re-run the stringer command to generate them again.
+	var x [1]struct{}
+	_ = x[InvalidSource-255]
+	_ = x[ImmSource-0]
+	_ = x[RegSource-8]
+}
+
+const (
+	_Source_name_0 = "ImmSource"
+	_Source_name_1 = "RegSource"
+	_Source_name_2 = "InvalidSource"
+)
+
+func (i Source) String() string {
+	switch {
+	case i == 0:
+		return _Source_name_0
+	case i == 8:
+		return _Source_name_1
+	case i == 255:
+		return _Source_name_2
+	default:
+		return "Source(" + strconv.FormatInt(int64(i), 10) + ")"
+	}
+}
+func _() {
+	// An "invalid array index" compiler error signifies that the constant values have changed.
+	// Re-run the stringer command to generate them again.
+	var x [1]struct{}
+	_ = x[InvalidEndian-255]
+	_ = x[LE-0]
+	_ = x[BE-8]
+}
+
+const (
+	_Endianness_name_0 = "LE"
+	_Endianness_name_1 = "BE"
+	_Endianness_name_2 = "InvalidEndian"
+)
+
+func (i Endianness) String() string {
+	switch {
+	case i == 0:
+		return _Endianness_name_0
+	case i == 8:
+		return _Endianness_name_1
+	case i == 255:
+		return _Endianness_name_2
+	default:
+		return "Endianness(" + strconv.FormatInt(int64(i), 10) + ")"
+	}
+}
+func _() {
+	// An "invalid array index" compiler error signifies that the constant values have changed.
+	// Re-run the stringer command to generate them again.
+	var x [1]struct{}
+	_ = x[InvalidALUOp-255]
+	_ = x[Add-0]
+	_ = x[Sub-16]
+	_ = x[Mul-32]
+	_ = x[Div-48]
+	_ = x[Or-64]
+	_ = x[And-80]
+	_ = x[LSh-96]
+	_ = x[RSh-112]
+	_ = x[Neg-128]
+	_ = x[Mod-144]
+	_ = x[Xor-160]
+	_ = x[Mov-176]
+	_ = x[ArSh-192]
+	_ = x[Swap-208]
+}
+
+const _ALUOp_name = "AddSubMulDivOrAndLShRShNegModXorMovArShSwapInvalidALUOp"
+
+var _ALUOp_map = map[ALUOp]string{
+	0:   _ALUOp_name[0:3],
+	16:  _ALUOp_name[3:6],
+	32:  _ALUOp_name[6:9],
+	48:  _ALUOp_name[9:12],
+	64:  _ALUOp_name[12:14],
+	80:  _ALUOp_name[14:17],
+	96:  _ALUOp_name[17:20],
+	112: _ALUOp_name[20:23],
+	128: _ALUOp_name[23:26],
+	144: _ALUOp_name[26:29],
+	160: _ALUOp_name[29:32],
+	176: _ALUOp_name[32:35],
+	192: _ALUOp_name[35:39],
+	208: _ALUOp_name[39:43],
+	255: _ALUOp_name[43:55],
+}
+
+func (i ALUOp) String() string {
+	if str, ok := _ALUOp_map[i]; ok {
+		return str
+	}
+	return "ALUOp(" + strconv.FormatInt(int64(i), 10) + ")"
+}

vendor/github.com/cilium/ebpf/asm/doc.go

@@ -0,0 +1,2 @@
+// Package asm is an assembler for eBPF bytecode.
+package asm

vendor/github.com/cilium/ebpf/asm/func.go

@@ -0,0 +1,143 @@
+package asm
+
+//go:generate stringer -output func_string.go -type=BuiltinFunc
+
+// BuiltinFunc is a built-in eBPF function.
+type BuiltinFunc int32
+
+// eBPF built-in functions
+//
+// You can renegerate this list using the following gawk script:
+//
+//    /FN\(.+\),/ {
+//      match($1, /\((.+)\)/, r)
+//      split(r[1], p, "_")
+//      printf "Fn"
+//      for (i in p) {
+//        printf "%s%s", toupper(substr(p[i], 1, 1)), substr(p[i], 2)
+//      }
+//      print ""
+//    }
+//
+// The script expects include/uapi/linux/bpf.h as it's input.
+const (
+	FnUnspec BuiltinFunc = iota
+	FnMapLookupElem
+	FnMapUpdateElem
+	FnMapDeleteElem
+	FnProbeRead
+	FnKtimeGetNs
+	FnTracePrintk
+	FnGetPrandomU32
+	FnGetSmpProcessorId
+	FnSkbStoreBytes
+	FnL3CsumReplace
+	FnL4CsumReplace
+	FnTailCall
+	FnCloneRedirect
+	FnGetCurrentPidTgid
+	FnGetCurrentUidGid
+	FnGetCurrentComm
+	FnGetCgroupClassid
+	FnSkbVlanPush
+	FnSkbVlanPop
+	FnSkbGetTunnelKey
+	FnSkbSetTunnelKey
+	FnPerfEventRead
+	FnRedirect
+	FnGetRouteRealm
+	FnPerfEventOutput
+	FnSkbLoadBytes
+	FnGetStackid
+	FnCsumDiff
+	FnSkbGetTunnelOpt
+	FnSkbSetTunnelOpt
+	FnSkbChangeProto
+	FnSkbChangeType
+	FnSkbUnderCgroup
+	FnGetHashRecalc
+	FnGetCurrentTask
+	FnProbeWriteUser
+	FnCurrentTaskUnderCgroup
+	FnSkbChangeTail
+	FnSkbPullData
+	FnCsumUpdate
+	FnSetHashInvalid
+	FnGetNumaNodeId
+	FnSkbChangeHead
+	FnXdpAdjustHead
+	FnProbeReadStr
+	FnGetSocketCookie
+	FnGetSocketUid
+	FnSetHash
+	FnSetsockopt
+	FnSkbAdjustRoom
+	FnRedirectMap
+	FnSkRedirectMap
+	FnSockMapUpdate
+	FnXdpAdjustMeta
+	FnPerfEventReadValue
+	FnPerfProgReadValue
+	FnGetsockopt
+	FnOverrideReturn
+	FnSockOpsCbFlagsSet
+	FnMsgRedirectMap
+	FnMsgApplyBytes
+	FnMsgCorkBytes
+	FnMsgPullData
+	FnBind
+	FnXdpAdjustTail
+	FnSkbGetXfrmState
+	FnGetStack
+	FnSkbLoadBytesRelative
+	FnFibLookup
+	FnSockHashUpdate
+	FnMsgRedirectHash
+	FnSkRedirectHash
+	FnLwtPushEncap
+	FnLwtSeg6StoreBytes
+	FnLwtSeg6AdjustSrh
+	FnLwtSeg6Action
+	FnRcRepeat
+	FnRcKeydown
+	FnSkbCgroupId
+	FnGetCurrentCgroupId
+	FnGetLocalStorage
+	FnSkSelectReuseport
+	FnSkbAncestorCgroupId
+	FnSkLookupTcp
+	FnSkLookupUdp
+	FnSkRelease
+	FnMapPushElem
+	FnMapPopElem
+	FnMapPeekElem
+	FnMsgPushData
+	FnMsgPopData
+	FnRcPointerRel
+	FnSpinLock
+	FnSpinUnlock
+	FnSkFullsock
+	FnTcpSock
+	FnSkbEcnSetCe
+	FnGetListenerSock
+	FnSkcLookupTcp
+	FnTcpCheckSyncookie
+	FnSysctlGetName
+	FnSysctlGetCurrentValue
+	FnSysctlGetNewValue
+	FnSysctlSetNewValue
+	FnStrtol
+	FnStrtoul
+	FnSkStorageGet
+	FnSkStorageDelete
+	FnSendSignal
+	FnTcpGenSyncookie
+)
+
+// Call emits a function call.
+func (fn BuiltinFunc) Call() Instruction {
+	return Instruction{
+		OpCode:   OpCode(JumpClass).SetJumpOp(Call),
+		Constant: int64(fn),
+	}
+}

vendor/github.com/cilium/ebpf/asm/func_string.go

@@ -0,0 +1,133 @@
+// Code generated by "stringer -output func_string.go -type=BuiltinFunc"; DO NOT EDIT.
+
+package asm
+
+import "strconv"
+
+func _() {
+	// An "invalid array index" compiler error signifies that the constant values have changed.
+	// Re-run the stringer command to generate them again.
+	var x [1]struct{}
+	_ = x[FnUnspec-0]
+	_ = x[FnMapLookupElem-1]
+	_ = x[FnMapUpdateElem-2]
+	_ = x[FnMapDeleteElem-3]
+	_ = x[FnProbeRead-4]
+	_ = x[FnKtimeGetNs-5]
+	_ = x[FnTracePrintk-6]
+	_ = x[FnGetPrandomU32-7]
+	_ = x[FnGetSmpProcessorId-8]
+	_ = x[FnSkbStoreBytes-9]
+	_ = x[FnL3CsumReplace-10]
+	_ = x[FnL4CsumReplace-11]
+	_ = x[FnTailCall-12]
+	_ = x[FnCloneRedirect-13]
+	_ = x[FnGetCurrentPidTgid-14]
+	_ = x[FnGetCurrentUidGid-15]
+	_ = x[FnGetCurrentComm-16]
+	_ = x[FnGetCgroupClassid-17]
+	_ = x[FnSkbVlanPush-18]
+	_ = x[FnSkbVlanPop-19]
+	_ = x[FnSkbGetTunnelKey-20]
+	_ = x[FnSkbSetTunnelKey-21]
+	_ = x[FnPerfEventRead-22]
+	_ = x[FnRedirect-23]
+	_ = x[FnGetRouteRealm-24]
+	_ = x[FnPerfEventOutput-25]
+	_ = x[FnSkbLoadBytes-26]
+	_ = x[FnGetStackid-27]
+	_ = x[FnCsumDiff-28]
+	_ = x[FnSkbGetTunnelOpt-29]
+	_ = x[FnSkbSetTunnelOpt-30]
+	_ = x[FnSkbChangeProto-31]
+	_ = x[FnSkbChangeType-32]
+	_ = x[FnSkbUnderCgroup-33]
+	_ = x[FnGetHashRecalc-34]
+	_ = x[FnGetCurrentTask-35]
+	_ = x[FnProbeWriteUser-36]
+	_ = x[FnCurrentTaskUnderCgroup-37]
+	_ = x[FnSkbChangeTail-38]
+	_ = x[FnSkbPullData-39]
+	_ = x[FnCsumUpdate-40]
+	_ = x[FnSetHashInvalid-41]
+	_ = x[FnGetNumaNodeId-42]
+	_ = x[FnSkbChangeHead-43]
+	_ = x[FnXdpAdjustHead-44]
+	_ = x[FnProbeReadStr-45]
+	_ = x[FnGetSocketCookie-46]
+	_ = x[FnGetSocketUid-47]
+	_ = x[FnSetHash-48]
+	_ = x[FnSetsockopt-49]
+	_ = x[FnSkbAdjustRoom-50]
+	_ = x[FnRedirectMap-51]
+	_ = x[FnSkRedirectMap-52]
+	_ = x[FnSockMapUpdate-53]
+	_ = x[FnXdpAdjustMeta-54]
+	_ = x[FnPerfEventReadValue-55]
+	_ = x[FnPerfProgReadValue-56]
+	_ = x[FnGetsockopt-57]
+	_ = x[FnOverrideReturn-58]
+	_ = x[FnSockOpsCbFlagsSet-59]
+	_ = x[FnMsgRedirectMap-60]
+	_ = x[FnMsgApplyBytes-61]
+	_ = x[FnMsgCorkBytes-62]
+	_ = x[FnMsgPullData-63]
+	_ = x[FnBind-64]
+	_ = x[FnXdpAdjustTail-65]
+	_ = x[FnSkbGetXfrmState-66]
+	_ = x[FnGetStack-67]
+	_ = x[FnSkbLoadBytesRelative-68]
+	_ = x[FnFibLookup-69]
+	_ = x[FnSockHashUpdate-70]
+	_ = x[FnMsgRedirectHash-71]
+	_ = x[FnSkRedirectHash-72]
+	_ = x[FnLwtPushEncap-73]
+	_ = x[FnLwtSeg6StoreBytes-74]
+	_ = x[FnLwtSeg6AdjustSrh-75]
+	_ = x[FnLwtSeg6Action-76]
+	_ = x[FnRcRepeat-77]
+	_ = x[FnRcKeydown-78]
+	_ = x[FnSkbCgroupId-79]
+	_ = x[FnGetCurrentCgroupId-80]
+	_ = x[FnGetLocalStorage-81]
+	_ = x[FnSkSelectReuseport-82]
+	_ = x[FnSkbAncestorCgroupId-83]
+	_ = x[FnSkLookupTcp-84]
+	_ = x[FnSkLookupUdp-85]
+	_ = x[FnSkRelease-86]
+	_ = x[FnMapPushElem-87]
+	_ = x[FnMapPopElem-88]
+	_ = x[FnMapPeekElem-89]
+	_ = x[FnMsgPushData-90]
+	_ = x[FnMsgPopData-91]
+	_ = x[FnRcPointerRel-92]
+	_ = x[FnSpinLock-93]
+	_ = x[FnSpinUnlock-94]
+	_ = x[FnSkFullsock-95]
+	_ = x[FnTcpSock-96]
+	_ = x[FnSkbEcnSetCe-97]
+	_ = x[FnGetListenerSock-98]
+	_ = x[FnSkcLookupTcp-99]
+	_ = x[FnTcpCheckSyncookie-100]
+	_ = x[FnSysctlGetName-101]
+	_ = x[FnSysctlGetCurrentValue-102]
+	_ = x[FnSysctlGetNewValue-103]
+	_ = x[FnSysctlSetNewValue-104]
+	_ = x[FnStrtol-105]
+	_ = x[FnStrtoul-106]
+	_ = x[FnSkStorageGet-107]
+	_ = x[FnSkStorageDelete-108]
+	_ = x[FnSendSignal-109]
+	_ = x[FnTcpGenSyncookie-110]
+}
+
+const _BuiltinFunc_name = "FnUnspecFnMapLookupElemFnMapUpdateElemFnMapDeleteElemFnProbeReadFnKtimeGetNsFnTracePrintkFnGetPrandomU32FnGetSmpProcessorIdFnSkbStoreBytesFnL3CsumReplaceFnL4CsumReplaceFnTailCallFnCloneRedirectFnGetCurrentPidTgidFnGetCurrentUidGidFnGetCurrentCommFnGetCgroupClassidFnSkbVlanPushFnSkbVlanPopFnSkbGetTunnelKeyFnSkbSetTunnelKeyFnPerfEventReadFnRedirectFnGetRouteRealmFnPerfEventOutputFnSkbLoadBytesFnGetStackidFnCsumDiffFnSkbGetTunnelOptFnSkbSetTunnelOptFnSkbChangeProtoFnSkbChangeTypeFnSkbUnderCgroupFnGetHashRecalcFnGetCurrentTaskFnProbeWriteUserFnCurrentTaskUnderCgroupFnSkbChangeTailFnSkbPullDataFnCsumUpdateFnSetHashInvalidFnGetNumaNodeIdFnSkbChangeHeadFnXdpAdjustHeadFnProbeReadStrFnGetSocketCookieFnGetSocketUidFnSetHashFnSetsockoptFnSkbAdjustRoomFnRedirectMapFnSkRedirectMapFnSockMapUpdateFnXdpAdjustMetaFnPerfEventReadValueFnPerfProgReadValueFnGetsockoptFnOverrideReturnFnSockOpsCbFlagsSetFnMsgRedirectMapFnMsgApplyBytesFnMsgCorkBytesFnMsgPullDataFnBindFnXdpAdjustTailFnSkbGetXfrmStateFnGetStackFnSkbLoadBytesRelativeFnFibLookupFnSockHashUpdateFnMsgRedirectHashFnSkRedirectHashFnLwtPushEncapFnLwtSeg6StoreBytesFnLwtSeg6AdjustSrhFnLwtSeg6ActionFnRcRepeatFnRcKeydownFnSkbCgroupIdFnGetCurrentCgroupIdFnGetLocalStorageFnSkSelectReuseportFnSkbAncestorCgroupIdFnSkLookupTcpFnSkLookupUdpFnSkReleaseFnMapPushElemFnMapPopElemFnMapPeekElemFnMsgPushDataFnMsgPopDataFnRcPointerRelFnSpinLockFnSpinUnlockFnSkFullsockFnTcpSockFnSkbEcnSetCeFnGetListenerSockFnSkcLookupTcpFnTcpCheckSyncookieFnSysctlGetNameFnSysctlGetCurrentValueFnSysctlGetNewValueFnSysctlSetNewValueFnStrtolFnStrtoulFnSkStorageGetFnSkStorageDeleteFnSendSignalFnTcpGenSyncookie"
+
+var _BuiltinFunc_index = [...]uint16{0, 8, 23, 38, 53, 64, 76, 89, 104, 123, 138, 153, 168, 178, 193, 212, 230, 246, 264, 277, 289, 306, 323, 338, 348, 363, 380, 394, 406, 416, 433, 450, 466, 481, 497, 512, 528, 544, 568, 583, 596, 608, 624, 639, 654, 669, 683, 700, 714, 723, 735, 750, 763, 778, 793, 808, 828, 847, 859, 875, 894, 910, 925, 939, 952, 958, 973, 990, 1000, 1022, 1033, 1049, 1066, 1082, 1096, 1115, 1133, 1148, 1158, 1169, 1182, 1202, 1219, 1238, 1259, 1272, 1285, 1296, 1309, 1321, 1334, 1347, 1359, 1373, 1383, 1395, 1407, 1416, 1429, 1446, 1460, 1479, 1494, 1517, 1536, 1555, 1563, 1572, 1586, 1603, 1615, 1632}
+
+func (i BuiltinFunc) String() string {
+	if i < 0 || i >= BuiltinFunc(len(_BuiltinFunc_index)-1) {
+		return "BuiltinFunc(" + strconv.FormatInt(int64(i), 10) + ")"
+	}
+	return _BuiltinFunc_name[_BuiltinFunc_index[i]:_BuiltinFunc_index[i+1]]
+}

vendor/github.com/cilium/ebpf/asm/instruction.go

@@ -0,0 +1,498 @@
+package asm
+
+import (
+	"crypto/sha1"
+	"encoding/binary"
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"io"
+	"math"
+	"strings"
+
+	"github.com/cilium/ebpf/internal/unix"
+)
+
+// InstructionSize is the size of a BPF instruction in bytes
+const InstructionSize = 8
+
+// RawInstructionOffset is an offset in units of raw BPF instructions.
+type RawInstructionOffset uint64
+
+// Bytes returns the offset of an instruction in bytes.
+func (rio RawInstructionOffset) Bytes() uint64 {
+	return uint64(rio) * InstructionSize
+}
+
+// Instruction is a single eBPF instruction.
+type Instruction struct {
+	OpCode    OpCode
+	Dst       Register
+	Src       Register
+	Offset    int16
+	Constant  int64
+	Reference string
+	Symbol    string
+}
+
+// Sym creates a symbol.
+func (ins Instruction) Sym(name string) Instruction {
+	ins.Symbol = name
+	return ins
+}
+
+// Unmarshal decodes a BPF instruction.
+func (ins *Instruction) Unmarshal(r io.Reader, bo binary.ByteOrder) (uint64, error) {
+	var bi bpfInstruction
+	err := binary.Read(r, bo, &bi)
+	if err != nil {
+		return 0, err
+	}
+
+	ins.OpCode = bi.OpCode
+	ins.Offset = bi.Offset
+	ins.Constant = int64(bi.Constant)
+	ins.Dst, ins.Src, err = bi.Registers.Unmarshal(bo)
+	if err != nil {
+		return 0, fmt.Errorf("can't unmarshal registers: %s", err)
+	}
+
+	if !bi.OpCode.isDWordLoad() {
+		return InstructionSize, nil
+	}
+
+	var bi2 bpfInstruction
+	if err := binary.Read(r, bo, &bi2); err != nil {
+		// No Wrap, to avoid io.EOF clash
+		return 0, errors.New("64bit immediate is missing second half")
+	}
+	if bi2.OpCode != 0 || bi2.Offset != 0 || bi2.Registers != 0 {
+		return 0, errors.New("64bit immediate has non-zero fields")
+	}
+	ins.Constant = int64(uint64(uint32(bi2.Constant))<<32 | uint64(uint32(bi.Constant)))
+
+	return 2 * InstructionSize, nil
+}
+
+// Marshal encodes a BPF instruction.
+func (ins Instruction) Marshal(w io.Writer, bo binary.ByteOrder) (uint64, error) {
+	if ins.OpCode == InvalidOpCode {
+		return 0, errors.New("invalid opcode")
+	}
+
+	isDWordLoad := ins.OpCode.isDWordLoad()
+
+	cons := int32(ins.Constant)
+	if isDWordLoad {
+		// Encode least significant 32bit first for 64bit operations.
+		cons = int32(uint32(ins.Constant))
+	}
+
+	regs, err := newBPFRegisters(ins.Dst, ins.Src, bo)
+	if err != nil {
+		return 0, fmt.Errorf("can't marshal registers: %s", err)
+	}
+
+	bpfi := bpfInstruction{
+		ins.OpCode,
+		regs,
+		ins.Offset,
+		cons,
+	}
+
+	if err := binary.Write(w, bo, &bpfi); err != nil {
+		return 0, err
+	}
+
+	if !isDWordLoad {
+		return InstructionSize, nil
+	}
+
+	bpfi = bpfInstruction{
+		Constant: int32(ins.Constant >> 32),
+	}
+
+	if err := binary.Write(w, bo, &bpfi); err != nil {
+		return 0, err
+	}
+
+	return 2 * InstructionSize, nil
+}
+
+// RewriteMapPtr changes an instruction to use a new map fd.
+//
+// Returns an error if the instruction doesn't load a map.
+func (ins *Instruction) RewriteMapPtr(fd int) error {
+	if !ins.OpCode.isDWordLoad() {
+		return fmt.Errorf("%s is not a 64 bit load", ins.OpCode)
+	}
+
+	if ins.Src != PseudoMapFD && ins.Src != PseudoMapValue {
+		return errors.New("not a load from a map")
+	}
+
+	// Preserve the offset value for direct map loads.
+	offset := uint64(ins.Constant) & (math.MaxUint32 << 32)
+	rawFd := uint64(uint32(fd))
+	ins.Constant = int64(offset | rawFd)
+	return nil
+}
+
+func (ins *Instruction) mapPtr() uint32 {
+	return uint32(uint64(ins.Constant) & math.MaxUint32)
+}
+
+// RewriteMapOffset changes the offset of a direct load from a map.
+//
+// Returns an error if the instruction is not a direct load.
+func (ins *Instruction) RewriteMapOffset(offset uint32) error {
+	if !ins.OpCode.isDWordLoad() {
+		return fmt.Errorf("%s is not a 64 bit load", ins.OpCode)
+	}
+
+	if ins.Src != PseudoMapValue {
+		return errors.New("not a direct load from a map")
+	}
+
+	fd := uint64(ins.Constant) & math.MaxUint32
+	ins.Constant = int64(uint64(offset)<<32 | fd)
+	return nil
+}
+
+func (ins *Instruction) mapOffset() uint32 {
+	return uint32(uint64(ins.Constant) >> 32)
+}
+
+// isLoadFromMap returns true if the instruction loads from a map.
+//
+// This covers both loading the map pointer and direct map value loads.
+func (ins *Instruction) isLoadFromMap() bool {
+	return ins.OpCode == LoadImmOp(DWord) && (ins.Src == PseudoMapFD || ins.Src == PseudoMapValue)
+}
+
+// IsFunctionCall returns true if the instruction calls another BPF function.
+//
+// This is not the same thing as a BPF helper call.
+func (ins *Instruction) IsFunctionCall() bool {
+	return ins.OpCode.JumpOp() == Call && ins.Src == PseudoCall
+}
+
+// Format implements fmt.Formatter.
+func (ins Instruction) Format(f fmt.State, c rune) {
+	if c != 'v' {
+		fmt.Fprintf(f, "{UNRECOGNIZED: %c}", c)
+		return
+	}
+
+	op := ins.OpCode
+
+	if op == InvalidOpCode {
+		fmt.Fprint(f, "INVALID")
+		return
+	}
+
+	// Omit trailing space for Exit
+	if op.JumpOp() == Exit {
+		fmt.Fprint(f, op)
+		return
+	}
+
+	if ins.isLoadFromMap() {
+		fd := int32(ins.mapPtr())
+		switch ins.Src {
+		case PseudoMapFD:
+			fmt.Fprintf(f, "LoadMapPtr dst: %s fd: %d", ins.Dst, fd)
+
+		case PseudoMapValue:
+			fmt.Fprintf(f, "LoadMapValue dst: %s, fd: %d off: %d", ins.Dst, fd, ins.mapOffset())
+		}
+
+		goto ref
+	}
+
+	fmt.Fprintf(f, "%v ", op)
+	switch cls := op.Class(); cls {
+	case LdClass, LdXClass, StClass, StXClass:
+		switch op.Mode() {
+		case ImmMode:
+			fmt.Fprintf(f, "dst: %s imm: %d", ins.Dst, ins.Constant)
+		case AbsMode:
+			fmt.Fprintf(f, "imm: %d", ins.Constant)
+		case IndMode:
+			fmt.Fprintf(f, "dst: %s src: %s imm: %d", ins.Dst, ins.Src, ins.Constant)
+		case MemMode:
+			fmt.Fprintf(f, "dst: %s src: %s off: %d imm: %d", ins.Dst, ins.Src, ins.Offset, ins.Constant)
+		case XAddMode:
+			fmt.Fprintf(f, "dst: %s src: %s", ins.Dst, ins.Src)
+		}
+
+	case ALU64Class, ALUClass:
+		fmt.Fprintf(f, "dst: %s ", ins.Dst)
+		if op.ALUOp() == Swap || op.Source() == ImmSource {
+			fmt.Fprintf(f, "imm: %d", ins.Constant)
+		} else {
+			fmt.Fprintf(f, "src: %s", ins.Src)
+		}
+
+	case JumpClass:
+		switch jop := op.JumpOp(); jop {
+		case Call:
+			if ins.Src == PseudoCall {
+				// bpf-to-bpf call
+				fmt.Fprint(f, ins.Constant)
+			} else {
+				fmt.Fprint(f, BuiltinFunc(ins.Constant))
+			}
+
+		default:
+			fmt.Fprintf(f, "dst: %s off: %d ", ins.Dst, ins.Offset)
+			if op.Source() == ImmSource {
+				fmt.Fprintf(f, "imm: %d", ins.Constant)
+			} else {
+				fmt.Fprintf(f, "src: %s", ins.Src)
+			}
+		}
+	}
+
+ref:
+	if ins.Reference != "" {
+		fmt.Fprintf(f, " <%s>", ins.Reference)
+	}
+}
+
+// Instructions is an eBPF program.
+type Instructions []Instruction
+
+func (insns Instructions) String() string {
+	return fmt.Sprint(insns)
+}
+
+// RewriteMapPtr rewrites all loads of a specific map pointer to a new fd.
+//
+// Returns an error if the symbol isn't used, see IsUnreferencedSymbol.
+func (insns Instructions) RewriteMapPtr(symbol string, fd int) error {
+	if symbol == "" {
+		return errors.New("empty symbol")
+	}
+
+	found := false
+	for i := range insns {
+		ins := &insns[i]
+		if ins.Reference != symbol {
+			continue
+		}
+
+		if err := ins.RewriteMapPtr(fd); err != nil {
+			return err
+		}
+
+		found = true
+	}
+
+	if !found {
+		return &unreferencedSymbolError{symbol}
+	}
+
+	return nil
+}
+
+// SymbolOffsets returns the set of symbols and their offset in
+// the instructions.
+func (insns Instructions) SymbolOffsets() (map[string]int, error) {
+	offsets := make(map[string]int)
+
+	for i, ins := range insns {
+		if ins.Symbol == "" {
+			continue
+		}
+
+		if _, ok := offsets[ins.Symbol]; ok {
+			return nil, fmt.Errorf("duplicate symbol %s", ins.Symbol)
+		}
+
+		offsets[ins.Symbol] = i
+	}
+
+	return offsets, nil
+}
+
+// ReferenceOffsets returns the set of references and their offset in
+// the instructions.
+func (insns Instructions) ReferenceOffsets() map[string][]int {
+	offsets := make(map[string][]int)
+
+	for i, ins := range insns {
+		if ins.Reference == "" {
+			continue
+		}
+
+		offsets[ins.Reference] = append(offsets[ins.Reference], i)
+	}
+
+	return offsets
+}
+
+// Format implements fmt.Formatter.
+//
+// You can control indentation of symbols by
+// specifying a width. Setting a precision controls the indentation of
+// instructions.
+// The default character is a tab, which can be overriden by specifying
+// the ' ' space flag.
+func (insns Instructions) Format(f fmt.State, c rune) {
+	if c != 's' && c != 'v' {
+		fmt.Fprintf(f, "{UNKNOWN FORMAT '%c'}", c)
+		return
+	}
+
+	// Precision is better in this case, because it allows
+	// specifying 0 padding easily.
+	padding, ok := f.Precision()
+	if !ok {
+		padding = 1
+	}
+
+	indent := strings.Repeat("\t", padding)
+	if f.Flag(' ') {
+		indent = strings.Repeat(" ", padding)
+	}
+
+	symPadding, ok := f.Width()
+	if !ok {
+		symPadding = padding - 1
+	}
+	if symPadding < 0 {
+		symPadding = 0
+	}
+
+	symIndent := strings.Repeat("\t", symPadding)
+	if f.Flag(' ') {
+		symIndent = strings.Repeat(" ", symPadding)
+	}
+
+	// Guess how many digits we need at most, by assuming that all instructions
+	// are double wide.
+	highestOffset := len(insns) * 2
+	offsetWidth := int(math.Ceil(math.Log10(float64(highestOffset))))
+
+	iter := insns.Iterate()
+	for iter.Next() {
+		if iter.Ins.Symbol != "" {
+			fmt.Fprintf(f, "%s%s:\n", symIndent, iter.Ins.Symbol)
+		}
+		fmt.Fprintf(f, "%s%*d: %v\n", indent, offsetWidth, iter.Offset, iter.Ins)
+	}
+
+	return
+}
+
+// Marshal encodes a BPF program into the kernel format.
+func (insns Instructions) Marshal(w io.Writer, bo binary.ByteOrder) error {
+	for i, ins := range insns {
+		_, err := ins.Marshal(w, bo)
+		if err != nil {
+			return fmt.Errorf("instruction %d: %w", i, err)
+		}
+	}
+	return nil
+}
+
+// Tag calculates the kernel tag for a series of instructions.
+//
+// It mirrors bpf_prog_calc_tag in the kernel and so can be compared
+// to ProgramInfo.Tag to figure out whether a loaded program matches
+// certain instructions.
+func (insns Instructions) Tag(bo binary.ByteOrder) (string, error) {
+	h := sha1.New()
+	for i, ins := range insns {
+		if ins.isLoadFromMap() {
+			ins.Constant = 0
+		}
+		_, err := ins.Marshal(h, bo)
+		if err != nil {
+			return "", fmt.Errorf("instruction %d: %w", i, err)
+		}
+	}
+	return hex.EncodeToString(h.Sum(nil)[:unix.BPF_TAG_SIZE]), nil
+}
+
+// Iterate allows iterating a BPF program while keeping track of
+// various offsets.
+//
+// Modifying the instruction slice will lead to undefined behaviour.
+func (insns Instructions) Iterate() *InstructionIterator {
+	return &InstructionIterator{insns: insns}
+}
+
+// InstructionIterator iterates over a BPF program.
+type InstructionIterator struct {
+	insns Instructions
+	// The instruction in question.
+	Ins *Instruction
+	// The index of the instruction in the original instruction slice.
+	Index int
+	// The offset of the instruction in raw BPF instructions. This accounts
+	// for double-wide instructions.
+	Offset RawInstructionOffset
+}
+
+// Next returns true as long as there are any instructions remaining.
+func (iter *InstructionIterator) Next() bool {
+	if len(iter.insns) == 0 {
+		return false
+	}
+
+	if iter.Ins != nil {
+		iter.Index++
+		iter.Offset += RawInstructionOffset(iter.Ins.OpCode.rawInstructions())
+	}
+	iter.Ins = &iter.insns[0]
+	iter.insns = iter.insns[1:]
+	return true
+}
+
+type bpfInstruction struct {
+	OpCode    OpCode
+	Registers bpfRegisters
+	Offset    int16
+	Constant  int32
+}
+
+type bpfRegisters uint8
+
+func newBPFRegisters(dst, src Register, bo binary.ByteOrder) (bpfRegisters, error) {
+	switch bo {
+	case binary.LittleEndian:
+		return bpfRegisters((src << 4) | (dst & 0xF)), nil
+	case binary.BigEndian:
+		return bpfRegisters((dst << 4) | (src & 0xF)), nil
+	default:
+		return 0, fmt.Errorf("unrecognized ByteOrder %T", bo)
+	}
+}
+
+func (r bpfRegisters) Unmarshal(bo binary.ByteOrder) (dst, src Register, err error) {
+	switch bo {
+	case binary.LittleEndian:
+		return Register(r & 0xF), Register(r >> 4), nil
+	case binary.BigEndian:
+		return Register(r >> 4), Register(r & 0xf), nil
+	default:
+		return 0, 0, fmt.Errorf("unrecognized ByteOrder %T", bo)
+	}
+}
+
+type unreferencedSymbolError struct {
+	symbol string
+}
+
+func (use *unreferencedSymbolError) Error() string {
+	return fmt.Sprintf("unreferenced symbol %s", use.symbol)
+}
+
+// IsUnreferencedSymbol returns true if err was caused by
+// an unreferenced symbol.
+func IsUnreferencedSymbol(err error) bool {
+	_, ok := err.(*unreferencedSymbolError)
+	return ok
+}

vendor/github.com/cilium/ebpf/asm/jump.go

@@ -0,0 +1,109 @@
+package asm
+
+//go:generate stringer -output jump_string.go -type=JumpOp
+
+// JumpOp affect control flow.
+//
+//    msb      lsb
+//    +----+-+---+
+//    |OP  |s|cls|
+//    +----+-+---+
+type JumpOp uint8
+
+const jumpMask OpCode = aluMask
+
+const (
+	// InvalidJumpOp is returned by getters when invoked
+	// on non branch OpCodes
+	InvalidJumpOp JumpOp = 0xff
+	// Ja jumps by offset unconditionally
+	Ja JumpOp = 0x00
+	// JEq jumps by offset if r == imm
+	JEq JumpOp = 0x10
+	// JGT jumps by offset if r > imm
+	JGT JumpOp = 0x20
+	// JGE jumps by offset if r >= imm
+	JGE JumpOp = 0x30
+	// JSet jumps by offset if r & imm
+	JSet JumpOp = 0x40
+	// JNE jumps by offset if r != imm
+	JNE JumpOp = 0x50
+	// JSGT jumps by offset if signed r > signed imm
+	JSGT JumpOp = 0x60
+	// JSGE jumps by offset if signed r >= signed imm
+	JSGE JumpOp = 0x70
+	// Call builtin or user defined function from imm
+	Call JumpOp = 0x80
+	// Exit ends execution, with value in r0
+	Exit JumpOp = 0x90
+	// JLT jumps by offset if r < imm
+	JLT JumpOp = 0xa0
+	// JLE jumps by offset if r <= imm
+	JLE JumpOp = 0xb0
+	// JSLT jumps by offset if signed r < signed imm
+	JSLT JumpOp = 0xc0
+	// JSLE jumps by offset if signed r <= signed imm
+	JSLE JumpOp = 0xd0
+)
+
+// Return emits an exit instruction.
+//
+// Requires a return value in R0.
+func Return() Instruction {
+	return Instruction{
+		OpCode: OpCode(JumpClass).SetJumpOp(Exit),
+	}
+}
+
+// Op returns the OpCode for a given jump source.
+func (op JumpOp) Op(source Source) OpCode {
+	return OpCode(JumpClass).SetJumpOp(op).SetSource(source)
+}
+
+// Imm compares dst to value, and adjusts PC by offset if the condition is fulfilled.
+func (op JumpOp) Imm(dst Register, value int32, label string) Instruction {
+	if op == Exit || op == Call || op == Ja {
+		return Instruction{OpCode: InvalidOpCode}
+	}
+
+	return Instruction{
+		OpCode:    OpCode(JumpClass).SetJumpOp(op).SetSource(ImmSource),
+		Dst:       dst,
+		Offset:    -1,
+		Constant:  int64(value),
+		Reference: label,
+	}
+}
+
+// Reg compares dst to src, and adjusts PC by offset if the condition is fulfilled.
+func (op JumpOp) Reg(dst, src Register, label string) Instruction {
+	if op == Exit || op == Call || op == Ja {
+		return Instruction{OpCode: InvalidOpCode}
+	}
+
+	return Instruction{
+		OpCode:    OpCode(JumpClass).SetJumpOp(op).SetSource(RegSource),
+		Dst:       dst,
+		Src:       src,
+		Offset:    -1,
+		Reference: label,
+	}
+}
+
+// Label adjusts PC to the address of the label.
+func (op JumpOp) Label(label string) Instruction {
+	if op == Call {
+		return Instruction{
+			OpCode:    OpCode(JumpClass).SetJumpOp(Call),
+			Src:       PseudoCall,
+			Constant:  -1,
+			Reference: label,
+		}
+	}
+
+	return Instruction{
+		OpCode:    OpCode(JumpClass).SetJumpOp(op),
+		Offset:    -1,
+		Reference: label,
+	}
+}

vendor/github.com/cilium/ebpf/asm/jump_string.go

@@ -0,0 +1,53 @@
+// Code generated by "stringer -output jump_string.go -type=JumpOp"; DO NOT EDIT.
+
+package asm
+
+import "strconv"
+
+func _() {
+	// An "invalid array index" compiler error signifies that the constant values have changed.
+	// Re-run the stringer command to generate them again.
+	var x [1]struct{}
+	_ = x[InvalidJumpOp-255]
+	_ = x[Ja-0]
+	_ = x[JEq-16]
+	_ = x[JGT-32]
+	_ = x[JGE-48]
+	_ = x[JSet-64]
+	_ = x[JNE-80]
+	_ = x[JSGT-96]
+	_ = x[JSGE-112]
+	_ = x[Call-128]
+	_ = x[Exit-144]
+	_ = x[JLT-160]
+	_ = x[JLE-176]
+	_ = x[JSLT-192]
+	_ = x[JSLE-208]
+}
+
+const _JumpOp_name = "JaJEqJGTJGEJSetJNEJSGTJSGECallExitJLTJLEJSLTJSLEInvalidJumpOp"
+
+var _JumpOp_map = map[JumpOp]string{
+	0:   _JumpOp_name[0:2],
+	16:  _JumpOp_name[2:5],
+	32:  _JumpOp_name[5:8],
+	48:  _JumpOp_name[8:11],
+	64:  _JumpOp_name[11:15],
+	80:  _JumpOp_name[15:18],
+	96:  _JumpOp_name[18:22],
+	112: _JumpOp_name[22:26],
+	128: _JumpOp_name[26:30],
+	144: _JumpOp_name[30:34],
+	160: _JumpOp_name[34:37],
+	176: _JumpOp_name[37:40],
+	192: _JumpOp_name[40:44],
+	208: _JumpOp_name[44:48],
+	255: _JumpOp_name[48:61],
+}
+
+func (i JumpOp) String() string {
+	if str, ok := _JumpOp_map[i]; ok {
+		return str
+	}
+	return "JumpOp(" + strconv.FormatInt(int64(i), 10) + ")"
+}

vendor/github.com/cilium/ebpf/asm/load_store.go

@@ -0,0 +1,204 @@
+package asm
+
+//go:generate stringer -output load_store_string.go -type=Mode,Size
+
+// Mode for load and store operations
+//
+//    msb      lsb
+//    +---+--+---+
+//    |MDE|sz|cls|
+//    +---+--+---+
+type Mode uint8
+
+const modeMask OpCode = 0xe0
+
+const (
+	// InvalidMode is returned by getters when invoked
+	// on non load / store OpCodes
+	InvalidMode Mode = 0xff
+	// ImmMode - immediate value
+	ImmMode Mode = 0x00
+	// AbsMode - immediate value + offset
+	AbsMode Mode = 0x20
+	// IndMode - indirect (imm+src)
+	IndMode Mode = 0x40
+	// MemMode - load from memory
+	MemMode Mode = 0x60
+	// XAddMode - add atomically across processors.
+	XAddMode Mode = 0xc0
+)
+
+// Size of load and store operations
+//
+//    msb      lsb
+//    +---+--+---+
+//    |mde|SZ|cls|
+//    +---+--+---+
+type Size uint8
+
+const sizeMask OpCode = 0x18
+
+const (
+	// InvalidSize is returned by getters when invoked
+	// on non load / store OpCodes
+	InvalidSize Size = 0xff
+	// DWord - double word; 64 bits
+	DWord Size = 0x18
+	// Word - word; 32 bits
+	Word Size = 0x00
+	// Half - half-word; 16 bits
+	Half Size = 0x08
+	// Byte - byte; 8 bits
+	Byte Size = 0x10
+)
+
+// Sizeof returns the size in bytes.
+func (s Size) Sizeof() int {
+	switch s {
+	case DWord:
+		return 8
+	case Word:
+		return 4
+	case Half:
+		return 2
+	case Byte:
+		return 1
+	default:
+		return -1
+	}
+}
+
+// LoadMemOp returns the OpCode to load a value of given size from memory.
+func LoadMemOp(size Size) OpCode {
+	return OpCode(LdXClass).SetMode(MemMode).SetSize(size)
+}
+
+// LoadMem emits `dst = *(size *)(src + offset)`.
+func LoadMem(dst, src Register, offset int16, size Size) Instruction {
+	return Instruction{
+		OpCode: LoadMemOp(size),
+		Dst:    dst,
+		Src:    src,
+		Offset: offset,
+	}
+}
+
+// LoadImmOp returns the OpCode to load an immediate of given size.
+//
+// As of kernel 4.20, only DWord size is accepted.
+func LoadImmOp(size Size) OpCode {
+	return OpCode(LdClass).SetMode(ImmMode).SetSize(size)
+}
+
+// LoadImm emits `dst = (size)value`.
+//
+// As of kernel 4.20, only DWord size is accepted.
+func LoadImm(dst Register, value int64, size Size) Instruction {
+	return Instruction{
+		OpCode:   LoadImmOp(size),
+		Dst:      dst,
+		Constant: value,
+	}
+}
+
+// LoadMapPtr stores a pointer to a map in dst.
+func LoadMapPtr(dst Register, fd int) Instruction {
+	if fd < 0 {
+		return Instruction{OpCode: InvalidOpCode}
+	}
+
+	return Instruction{
+		OpCode:   LoadImmOp(DWord),
+		Dst:      dst,
+		Src:      PseudoMapFD,
+		Constant: int64(fd),
+	}
+}
+
+// LoadMapValue stores a pointer to the value at a certain offset of a map.
+func LoadMapValue(dst Register, fd int, offset uint32) Instruction {
+	if fd < 0 {
+		return Instruction{OpCode: InvalidOpCode}
+	}
+
+	fdAndOffset := (uint64(offset) << 32) | uint64(uint32(fd))
+	return Instruction{
+		OpCode:   LoadImmOp(DWord),
+		Dst:      dst,
+		Src:      PseudoMapValue,
+		Constant: int64(fdAndOffset),
+	}
+}
+
+// LoadIndOp returns the OpCode for loading a value of given size from an sk_buff.
+func LoadIndOp(size Size) OpCode {
+	return OpCode(LdClass).SetMode(IndMode).SetSize(size)
+}
+
+// LoadInd emits `dst = ntoh(*(size *)(((sk_buff *)R6)->data + src + offset))`.
+func LoadInd(dst, src Register, offset int32, size Size) Instruction {
+	return Instruction{
+		OpCode:   LoadIndOp(size),
+		Dst:      dst,
+		Src:      src,
+		Constant: int64(offset),
+	}
+}
+
+// LoadAbsOp returns the OpCode for loading a value of given size from an sk_buff.
+func LoadAbsOp(size Size) OpCode {
+	return OpCode(LdClass).SetMode(AbsMode).SetSize(size)
+}
+
+// LoadAbs emits `r0 = ntoh(*(size *)(((sk_buff *)R6)->data + offset))`.
+func LoadAbs(offset int32, size Size) Instruction {
+	return Instruction{
+		OpCode:   LoadAbsOp(size),
+		Dst:      R0,
+		Constant: int64(offset),
+	}
+}
+
+// StoreMemOp returns the OpCode for storing a register of given size in memory.
+func StoreMemOp(size Size) OpCode {
+	return OpCode(StXClass).SetMode(MemMode).SetSize(size)
+}
+
+// StoreMem emits `*(size *)(dst + offset) = src`
+func StoreMem(dst Register, offset int16, src Register, size Size) Instruction {
+	return Instruction{
+		OpCode: StoreMemOp(size),
+		Dst:    dst,
+		Src:    src,
+		Offset: offset,
+	}
+}
+
+// StoreImmOp returns the OpCode for storing an immediate of given size in memory.
+func StoreImmOp(size Size) OpCode {
+	return OpCode(StClass).SetMode(MemMode).SetSize(size)
+}
+
+// StoreImm emits `*(size *)(dst + offset) = value`.
+func StoreImm(dst Register, offset int16, value int64, size Size) Instruction {
+	return Instruction{
+		OpCode:   StoreImmOp(size),
+		Dst:      dst,
+		Offset:   offset,
+		Constant: value,
+	}
+}
+
+// StoreXAddOp returns the OpCode to atomically add a register to a value in memory.
+func StoreXAddOp(size Size) OpCode {
+	return OpCode(StXClass).SetMode(XAddMode).SetSize(size)
+}
+
+// StoreXAdd atomically adds src to *dst.
+func StoreXAdd(dst, src Register, size Size) Instruction {
+	return Instruction{
+		OpCode: StoreXAddOp(size),
+		Dst:    dst,
+		Src:    src,
+	}
+}

vendor/github.com/cilium/ebpf/asm/load_store_string.go

@@ -0,0 +1,80 @@
+// Code generated by "stringer -output load_store_string.go -type=Mode,Size"; DO NOT EDIT.
+
+package asm
+
+import "strconv"
+
+func _() {
+	// An "invalid array index" compiler error signifies that the constant values have changed.
+	// Re-run the stringer command to generate them again.
+	var x [1]struct{}
+	_ = x[InvalidMode-255]
+	_ = x[ImmMode-0]
+	_ = x[AbsMode-32]
+	_ = x[IndMode-64]
+	_ = x[MemMode-96]
+	_ = x[XAddMode-192]
+}
+
+const (
+	_Mode_name_0 = "ImmMode"
+	_Mode_name_1 = "AbsMode"
+	_Mode_name_2 = "IndMode"
+	_Mode_name_3 = "MemMode"
+	_Mode_name_4 = "XAddMode"
+	_Mode_name_5 = "InvalidMode"
+)
+
+func (i Mode) String() string {
+	switch {
+	case i == 0:
+		return _Mode_name_0
+	case i == 32:
+		return _Mode_name_1
+	case i == 64:
+		return _Mode_name_2
+	case i == 96:
+		return _Mode_name_3
+	case i == 192:
+		return _Mode_name_4
+	case i == 255:
+		return _Mode_name_5
+	default:
+		return "Mode(" + strconv.FormatInt(int64(i), 10) + ")"
+	}
+}
+func _() {
+	// An "invalid array index" compiler error signifies that the constant values have changed.
+	// Re-run the stringer command to generate them again.
+	var x [1]struct{}
+	_ = x[InvalidSize-255]
+	_ = x[DWord-24]
+	_ = x[Word-0]
+	_ = x[Half-8]
+	_ = x[Byte-16]
+}
+
+const (
+	_Size_name_0 = "Word"
+	_Size_name_1 = "Half"
+	_Size_name_2 = "Byte"
+	_Size_name_3 = "DWord"
+	_Size_name_4 = "InvalidSize"
+)
+
+func (i Size) String() string {
+	switch {
+	case i == 0:
+		return _Size_name_0
+	case i == 8:
+		return _Size_name_1
+	case i == 16:
+		return _Size_name_2
+	case i == 24:
+		return _Size_name_3
+	case i == 255:
+		return _Size_name_4
+	default:
+		return "Size(" + strconv.FormatInt(int64(i), 10) + ")"
+	}
+}

vendor/github.com/cilium/ebpf/asm/opcode.go

@@ -0,0 +1,237 @@
+package asm
+
+import (
+	"fmt"
+	"strings"
+)
+
+//go:generate stringer -output opcode_string.go -type=Class
+
+type encoding int
+
+const (
+	unknownEncoding encoding = iota
+	loadOrStore
+	jumpOrALU
+)
+
+// Class of operations
+//
+//    msb      lsb
+//    +---+--+---+
+//    |  ??  |CLS|
+//    +---+--+---+
+type Class uint8
+
+const classMask OpCode = 0x07
+
+const (
+	// LdClass load memory
+	LdClass Class = 0x00
+	// LdXClass load memory from constant
+	LdXClass Class = 0x01
+	// StClass load register from memory
+	StClass Class = 0x02
+	// StXClass load register from constant
+	StXClass Class = 0x03
+	// ALUClass arithmetic operators
+	ALUClass Class = 0x04
+	// JumpClass jump operators
+	JumpClass Class = 0x05
+	// ALU64Class arithmetic in 64 bit mode
+	ALU64Class Class = 0x07
+)
+
+func (cls Class) encoding() encoding {
+	switch cls {
+	case LdClass, LdXClass, StClass, StXClass:
+		return loadOrStore
+	case ALU64Class, ALUClass, JumpClass:
+		return jumpOrALU
+	default:
+		return unknownEncoding
+	}
+}
+
+// OpCode is a packed eBPF opcode.
+//
+// Its encoding is defined by a Class value:
+//
+//    msb      lsb
+//    +----+-+---+
+//    | ???? |CLS|
+//    +----+-+---+
+type OpCode uint8
+
+// InvalidOpCode is returned by setters on OpCode
+const InvalidOpCode OpCode = 0xff
+
+// rawInstructions returns the number of BPF instructions required
+// to encode this opcode.
+func (op OpCode) rawInstructions() int {
+	if op.isDWordLoad() {
+		return 2
+	}
+	return 1
+}
+
+func (op OpCode) isDWordLoad() bool {
+	return op == LoadImmOp(DWord)
+}
+
+// Class returns the class of operation.
+func (op OpCode) Class() Class {
+	return Class(op & classMask)
+}
+
+// Mode returns the mode for load and store operations.
+func (op OpCode) Mode() Mode {
+	if op.Class().encoding() != loadOrStore {
+		return InvalidMode
+	}
+	return Mode(op & modeMask)
+}
+
+// Size returns the size for load and store operations.
+func (op OpCode) Size() Size {
+	if op.Class().encoding() != loadOrStore {
+		return InvalidSize
+	}
+	return Size(op & sizeMask)
+}
+
+// Source returns the source for branch and ALU operations.
+func (op OpCode) Source() Source {
+	if op.Class().encoding() != jumpOrALU || op.ALUOp() == Swap {
+		return InvalidSource
+	}
+	return Source(op & sourceMask)
+}
+
+// ALUOp returns the ALUOp.
+func (op OpCode) ALUOp() ALUOp {
+	if op.Class().encoding() != jumpOrALU {
+		return InvalidALUOp
+	}
+	return ALUOp(op & aluMask)
+}
+
+// Endianness returns the Endianness for a byte swap instruction.
+func (op OpCode) Endianness() Endianness {
+	if op.ALUOp() != Swap {
+		return InvalidEndian
+	}
+	return Endianness(op & endianMask)
+}
+
+// JumpOp returns the JumpOp.
+func (op OpCode) JumpOp() JumpOp {
+	if op.Class().encoding() != jumpOrALU {
+		return InvalidJumpOp
+	}
+	return JumpOp(op & jumpMask)
+}
+
+// SetMode sets the mode on load and store operations.
+//
+// Returns InvalidOpCode if op is of the wrong class.
+func (op OpCode) SetMode(mode Mode) OpCode {
+	if op.Class().encoding() != loadOrStore || !valid(OpCode(mode), modeMask) {
+		return InvalidOpCode
+	}
+	return (op & ^modeMask) | OpCode(mode)
+}
+
+// SetSize sets the size on load and store operations.
+//
+// Returns InvalidOpCode if op is of the wrong class.
+func (op OpCode) SetSize(size Size) OpCode {
+	if op.Class().encoding() != loadOrStore || !valid(OpCode(size), sizeMask) {
+		return InvalidOpCode
+	}
+	return (op & ^sizeMask) | OpCode(size)
+}
+
+// SetSource sets the source on jump and ALU operations.
+//
+// Returns InvalidOpCode if op is of the wrong class.
+func (op OpCode) SetSource(source Source) OpCode {
+	if op.Class().encoding() != jumpOrALU || !valid(OpCode(source), sourceMask) {
+		return InvalidOpCode
+	}
+	return (op & ^sourceMask) | OpCode(source)
+}
+
+// SetALUOp sets the ALUOp on ALU operations.
+//
+// Returns InvalidOpCode if op is of the wrong class.
+func (op OpCode) SetALUOp(alu ALUOp) OpCode {
+	class := op.Class()
+	if (class != ALUClass && class != ALU64Class) || !valid(OpCode(alu), aluMask) {
+		return InvalidOpCode
+	}
+	return (op & ^aluMask) | OpCode(alu)
+}
+
+// SetJumpOp sets the JumpOp on jump operations.
+//
+// Returns InvalidOpCode if op is of the wrong class.
+func (op OpCode) SetJumpOp(jump JumpOp) OpCode {
+	if op.Class() != JumpClass || !valid(OpCode(jump), jumpMask) {
+		return InvalidOpCode
+	}
+	return (op & ^jumpMask) | OpCode(jump)
+}
+
+func (op OpCode) String() string {
+	var f strings.Builder
+
+	switch class := op.Class(); class {
+	case LdClass, LdXClass, StClass, StXClass:
+		f.WriteString(strings.TrimSuffix(class.String(), "Class"))
+
+		mode := op.Mode()
+		f.WriteString(strings.TrimSuffix(mode.String(), "Mode"))
+
+		switch op.Size() {
+		case DWord:
+			f.WriteString("DW")
+		case Word:
+			f.WriteString("W")
+		case Half:
+			f.WriteString("H")
+		case Byte:
+			f.WriteString("B")
+		}
+
+	case ALU64Class, ALUClass:
+		f.WriteString(op.ALUOp().String())
+
+		if op.ALUOp() == Swap {
+			// Width for Endian is controlled by Constant
+			f.WriteString(op.Endianness().String())
+		} else {
+			if class == ALUClass {
+				f.WriteString("32")
+			}
+
+			f.WriteString(strings.TrimSuffix(op.Source().String(), "Source"))
+		}
+
+	case JumpClass:
+		f.WriteString(op.JumpOp().String())
+		if jop := op.JumpOp(); jop != Exit && jop != Call {
+			f.WriteString(strings.TrimSuffix(op.Source().String(), "Source"))
+		}
+
+	default:
+		fmt.Fprintf(&f, "OpCode(%#x)", uint8(op))
+	}
+
+	return f.String()
+}
+
+// valid returns true if all bits in value are covered by mask.
+func valid(value, mask OpCode) bool {
+	return value & ^mask == 0
+}

vendor/github.com/cilium/ebpf/asm/opcode_string.go

@@ -0,0 +1,38 @@
+// Code generated by "stringer -output opcode_string.go -type=Class"; DO NOT EDIT.
+
+package asm
+
+import "strconv"
+
+func _() {
+	// An "invalid array index" compiler error signifies that the constant values have changed.
+	// Re-run the stringer command to generate them again.
+	var x [1]struct{}
+	_ = x[LdClass-0]
+	_ = x[LdXClass-1]
+	_ = x[StClass-2]
+	_ = x[StXClass-3]
+	_ = x[ALUClass-4]
+	_ = x[JumpClass-5]
+	_ = x[ALU64Class-7]
+}
+
+const (
+	_Class_name_0 = "LdClassLdXClassStClassStXClassALUClassJumpClass"
+	_Class_name_1 = "ALU64Class"
+)
+
+var (
+	_Class_index_0 = [...]uint8{0, 7, 15, 22, 30, 38, 47}
+)
+
+func (i Class) String() string {
+	switch {
+	case 0 <= i && i <= 5:
+		return _Class_name_0[_Class_index_0[i]:_Class_index_0[i+1]]
+	case i == 7:
+		return _Class_name_1
+	default:
+		return "Class(" + strconv.FormatInt(int64(i), 10) + ")"
+	}
+}

vendor/github.com/cilium/ebpf/asm/register.go

@@ -0,0 +1,49 @@
+package asm
+
+import (
+	"fmt"
+)
+
+// Register is the source or destination of most operations.
+type Register uint8
+
+// R0 contains return values.
+const R0 Register = 0
+
+// Registers for function arguments.
+const (
+	R1 Register = R0 + 1 + iota
+	R2
+	R3
+	R4
+	R5
+)
+
+// Callee saved registers preserved by function calls.
+const (
+	R6 Register = R5 + 1 + iota
+	R7
+	R8
+	R9
+)
+
+// Read-only frame pointer to access stack.
+const (
+	R10 Register = R9 + 1
+	RFP          = R10
+)
+
+// Pseudo registers used by 64bit loads and jumps
+const (
+	PseudoMapFD    = R1 // BPF_PSEUDO_MAP_FD
+	PseudoMapValue = R2 // BPF_PSEUDO_MAP_VALUE
+	PseudoCall     = R1 // BPF_PSEUDO_CALL
+)
+
+func (r Register) String() string {
+	v := uint8(r)
+	if v == 10 {
+		return "rfp"
+	}
+	return fmt.Sprintf("r%d", v)
+}