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// Copyright 2024 The gVisor Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package linux
// This file contains constants required to support nf_tables.
// 16-byte Registers that can be used to maintain state for rules.
// These correspond to values in include/uapi/linux/netfilter/nf_tables.h.
const (
NFT_REG_VERDICT = iota
NFT_REG_1
NFT_REG_2
NFT_REG_3
NFT_REG_4
__NFT_REG_MAX
)
// 4-byte Registers that can be used to maintain state for rules.
// Note that these overlap with the 16-byte registers in memory.
// These correspond to values in include/uapi/linux/netfilter/nf_tables.h.
const (
NFT_REG32_00 = 8 + iota
NFT_REG32_01
NFT_REG32_02
NFT_REG32_03
NFT_REG32_04
NFT_REG32_05
NFT_REG32_06
NFT_REG32_07
NFT_REG32_08
NFT_REG32_09
NFT_REG32_10
NFT_REG32_11
NFT_REG32_12
NFT_REG32_13
NFT_REG32_14
NFT_REG32_15
)
// Other register constants, corresponding to values in
// include/uapi/linux/netfilter/nf_tables.h.
const (
NFT_REG_MAX = __NFT_REG_MAX - 1 // Maximum register value
NFT_REG_SIZE = 16 // Size of NFT_REG
NFT_REG32_SIZE = 4 // Size of NFT_REG32
NFT_REG32_COUNT = NFT_REG32_15 - NFT_REG32_00 + 1 // Count of 4-byte registers
)
// Internal nf table verdicts. These are used for ruleset evaluation and
// are not returned to userspace.
//
// These also share their numeric name space with the netfilter verdicts. When
// used these values are converted to uint32 (purposefully overflowing the int).
// These correspond to values in include/uapi/linux/netfilter/nf_tables.h.
const (
// Continue evaluation of the current rule.
NFT_CONTINUE int32 = -1
// Terminate evaluation of the current rule.
NFT_BREAK int32 = -2
// Push the current chain on the jump stack and jump to a chain.
NFT_JUMP int32 = -3
// Jump to a chain without pushing the current chain on the jump stack.
NFT_GOTO int32 = -4
// Return to the topmost chain on the jump stack.
NFT_RETURN int32 = -5
)
// Nf table relational operators.
// Used by the nft comparison operation to compare values in registers.
// These correspond to enum values in include/uapi/linux/netfilter/nf_tables.h.
const (
NFT_CMP_EQ = iota // equal
NFT_CMP_NEQ // not equal
NFT_CMP_LT // less than
NFT_CMP_LTE // less than or equal to
NFT_CMP_GT // greater than
NFT_CMP_GTE // greater than or equal to
)
// Nf table range operators.
// Used by the nft range operation to compare values in registers.
// These correspond to enum values in include/uapi/linux/netfilter/nf_tables.h.
const (
NFT_RANGE_EQ = iota
NFT_RANGE_NEQ
)
// Nf table payload expression offset bases.
// Used by the nft payload operations to access appropriate data in the packet.
// These correspond to enum values in include/uapi/linux/netfilter/nf_tables.h.
const (
NFT_PAYLOAD_LL_HEADER = iota // link layer header
NFT_PAYLOAD_NETWORK_HEADER // network header
NFT_PAYLOAD_TRANSPORT_HEADER // transport header
NFT_PAYLOAD_INNER_HEADER // inner header / payload
NFT_PAYLOAD_TUN_HEADER // tunneling protocol header
)
// Nf table payload expression checksum types.
// Used by the nft payload set operation to mark the type of checksum to use.
// These correspond to enum values in include/uapi/linux/netfilter/nf_tables.h.
const (
NFT_PAYLOAD_CSUM_NONE = iota // no checksumming
NFT_PAYLOAD_CSUM_INET // internet checksum (RFC 791)
NFT_PAYLOAD_CSUM_SCTP // CRC-32c, for use in SCTP header (RFC 3309)
)
// Nf table payload expression checksum flags.
// Used by the nft payload set operation to mark the flags for checksumming.
// These correspond to enum values in include/uapi/linux/netfilter/nf_tables.h.
const (
NFT_PAYLOAD_L4CSUM_PSEUDOHDR = (1 << 0) // use pseudoheader for L4 checksum
)
// Nf table bitwise operators.
// Used by the nft bitwise operation to perform bitwise math over register data.
// These correspond to enum values in include/uapi/linux/netfilter/nf_tables.h.
const (
NFT_BITWISE_BOOL = iota // mask-and-xor operation for NOT, AND, OR, & XOR
NFT_BITWISE_LSHIFT // left-shift operation
NFT_BITWISE_RSHIFT // right-shift operation
)
// Nf table route expression keys.
// Used by the nft route operation to determine the routing data to retrieve.
// These correspond to enum values in include/uapi/linux/netfilter/nf_tables.h.
const (
// Traffic Class Identifier (Realm) associated with route
NFT_RT_CLASSID = iota
// Routing nexthop for IPv4 (next IPv4 address to jump to)
NFT_RT_NEXTHOP4
// Routing nexthop for IPv6 (next IPv6 address to jump to)
NFT_RT_NEXTHOP6
// Maximum Segment Size for TCP connections (largest size for a single packet)
NFT_RT_TCPMSS
// Bool for whether packet route involves a IPsec transform st xfrm is applied
NFT_RT_XFRM
)
// Nf table byteorder operators.
// Used by the nft byteorder operation to convert data in a register to a
// specific byte order.
// These correspond to enum values in include/uapi/linux/netfilter/nf_tables.h.
const (
NFT_BYTEORDER_NTOH = iota // network to host operator
NFT_BYTEORDER_HTON // host to network operator
)
// Nf tables meta expression keys.
// Used by the nft meta operation to retrieve meta data from the packet.
// These correspond to enum values in include/uapi/linux/netfilter/nf_tables.h.
const (
NFT_META_LEN = iota // Packet length
NFT_META_PROTOCOL // Packet ethertype protocol, invalid in OUTPUT
NFT_META_PRIORITY // Packet priority
NFT_META_MARK // Packet mark
NFT_META_IIF // Packet input interface index
NFT_META_OIF // Packet output interface index
NFT_META_IIFNAME // Packet input interface name
NFT_META_OIFNAME // Packet output interface name
NFT_META_IIFTYPE // Packet input interface type
NFT_META_OIFTYPE // Packet output interface type
NFT_META_SKUID // Originating socket UID
NFT_META_SKGID // Originating socket GID
NFT_META_NFTRACE // Packet nftrace bit
NFT_META_RTCLASSID // Realm value of packet's route
NFT_META_SECMARK // Packet secmark
NFT_META_NFPROTO // Netfilter protocol
NFT_META_L4PROTO // Layer 4 protocol number
NFT_META_BRI_IIFNAME // Packet input bridge interface name
NFT_META_BRI_OIFNAME // Packet output bridge interface name
NFT_META_PKTTYPE // Packet type, special handling for loopback
NFT_META_CPU // CPU id through smp_processor_id()
NFT_META_IIFGROUP // Packet input interface group
NFT_META_OIFGROUP // Packet output interface group
NFT_META_CGROUP // Socket control group
NFT_META_PRANDOM // A 32bit pseudo-random number
NFT_META_SECPATH // Boolean, secpath_exists
NFT_META_IIFKIND // Packet input interface kind name
NFT_META_OIFKIND // Packet output interface kind name
NFT_META_BRI_IIFPVID // Packet input bridge port pvid
NFT_META_BRI_IIFVPROTO // Packet input bridge vlan proto
NFT_META_TIME_NS // Time since epoch (in nanoseconds)
NFT_META_TIME_DAY // Day of week (from 0 = Sunday to 6 = Saturday)
NFT_META_TIME_HOUR // Hour of day (in sec), secs since start of day
NFT_META_SDIF // Slave device interface index
NFT_META_SDIFNAME // Slave device interface name
NFT_META_BRI_BROUTE // Packet br_netfilter_broute bit
)