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tun: implement UDP GSO/GRO for Linux

Browse Source 
Implement UDP GSO and GRO for the Linux tun.Device, which is made
possible by virtio extensions in the kernel's TUN driver starting in
v6.2.

secnetperf, a QUIC benchmark utility from microsoft/msquic@8e1eb1a, is
used to demonstrate the effect of this commit between two Linux
computers with i5-12400 CPUs. There is roughly ~13us of round trip
latency between them. secnetperf was invoked with the following command
line options:
-stats:1 -exec:maxtput -test:tput -download:10000 -timed:1 -encrypt:0

The first result is from commit 2e0774f without UDP GSO/GRO on the TUN.

[conn][0x55739a144980] STATS: EcnCapable=0 RTT=3973 us
SendTotalPackets=55859 SendSuspectedLostPackets=61
SendSpuriousLostPackets=59 SendCongestionCount=27
SendEcnCongestionCount=0 RecvTotalPackets=2779122
RecvReorderedPackets=0 RecvDroppedPackets=0
RecvDuplicatePackets=0 RecvDecryptionFailures=0
Result: 3654977571 bytes @ 2922821 kbps (10003.972 ms).

The second result is with UDP GSO/GRO on the TUN.

[conn][0x56493dfd09a0] STATS: EcnCapable=0 RTT=1216 us
SendTotalPackets=165033 SendSuspectedLostPackets=64
SendSpuriousLostPackets=61 SendCongestionCount=53
SendEcnCongestionCount=0 RecvTotalPackets=11845268
RecvReorderedPackets=25267 RecvDroppedPackets=0
RecvDuplicatePackets=0 RecvDecryptionFailures=0
Result: 15574671184 bytes @ 12458214 kbps (10001.222 ms).

Signed-off-by: Jordan Whited <jordan@tailscale.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This commit is contained in:
Jordan Whited 2023-10-31 19:53:35 -07:00 committed by Jason A. Donenfeld
parent 1cf89f5339
commit d0bc03c707
6 changed files with 1258 additions and 590 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

584
tun/tcp_offload_linux.go → tun/offload_linux.go
View File

@ -57,22 +57,23 @@ const (
virtioNetHdrLen = int(unsafe.Sizeof(virtioNetHdr{}))
)
// flowKey represents the key for a flow.
type flowKey struct {
// tcpFlowKey represents the key for a TCP flow.
type tcpFlowKey struct {
srcAddr, dstAddr [16]byte
srcPort, dstPort uint16
rxAck uint32 // varying ack values should not be coalesced. Treat them as separate flows.
isV6 bool
}
// tcpGROTable holds flow and coalescing information for the purposes of GRO.
// tcpGROTable holds flow and coalescing information for the purposes of TCP GRO.
type tcpGROTable struct {
itemsByFlow map[flowKey][]tcpGROItem
itemsByFlow map[tcpFlowKey][]tcpGROItem
itemsPool [][]tcpGROItem
}
func newTCPGROTable() *tcpGROTable {
t := &tcpGROTable{
itemsByFlow: make(map[flowKey][]tcpGROItem, conn.IdealBatchSize),
itemsByFlow: make(map[tcpFlowKey][]tcpGROItem, conn.IdealBatchSize),
itemsPool: make([][]tcpGROItem, conn.IdealBatchSize),
}
for i := range t.itemsPool {
@ -81,14 +82,15 @@ func newTCPGROTable() *tcpGROTable {
return t
}
func newFlowKey(pkt []byte, srcAddr, dstAddr, tcphOffset int) flowKey {
key := flowKey{}
addrSize := dstAddr - srcAddr
copy(key.srcAddr[:], pkt[srcAddr:dstAddr])
copy(key.dstAddr[:], pkt[dstAddr:dstAddr+addrSize])
func newTCPFlowKey(pkt []byte, srcAddrOffset, dstAddrOffset, tcphOffset int) tcpFlowKey {
key := tcpFlowKey{}
addrSize := dstAddrOffset - srcAddrOffset
copy(key.srcAddr[:], pkt[srcAddrOffset:dstAddrOffset])
copy(key.dstAddr[:], pkt[dstAddrOffset:dstAddrOffset+addrSize])
key.srcPort = binary.BigEndian.Uint16(pkt[tcphOffset:])
key.dstPort = binary.BigEndian.Uint16(pkt[tcphOffset+2:])
key.rxAck = binary.BigEndian.Uint32(pkt[tcphOffset+8:])
key.isV6 = addrSize == 16
return key
}
@ -96,7 +98,7 @@ func newFlowKey(pkt []byte, srcAddr, dstAddr, tcphOffset int) flowKey {
// returning the packets found for the flow, or inserting a new one if none
// is found.
func (t *tcpGROTable) lookupOrInsert(pkt []byte, srcAddrOffset, dstAddrOffset, tcphOffset, tcphLen, bufsIndex int) ([]tcpGROItem, bool) {
key := newFlowKey(pkt, srcAddrOffset, dstAddrOffset, tcphOffset)
key := newTCPFlowKey(pkt, srcAddrOffset, dstAddrOffset, tcphOffset)
items, ok := t.itemsByFlow[key]
if ok {
return items, ok
@ -108,7 +110,7 @@ func (t *tcpGROTable) lookupOrInsert(pkt []byte, srcAddrOffset, dstAddrOffset, t
// insert an item in the table for the provided packet and packet metadata.
func (t *tcpGROTable) insert(pkt []byte, srcAddrOffset, dstAddrOffset, tcphOffset, tcphLen, bufsIndex int) {
key := newFlowKey(pkt, srcAddrOffset, dstAddrOffset, tcphOffset)
key := newTCPFlowKey(pkt, srcAddrOffset, dstAddrOffset, tcphOffset)
item := tcpGROItem{
key: key,
bufsIndex: uint16(bufsIndex),
@ -131,7 +133,7 @@ func (t *tcpGROTable) updateAt(item tcpGROItem, i int) {
items[i] = item
}
func (t *tcpGROTable) deleteAt(key flowKey, i int) {
func (t *tcpGROTable) deleteAt(key tcpFlowKey, i int) {
items, _ := t.itemsByFlow[key]
items = append(items[:i], items[i+1:]...)
t.itemsByFlow[key] = items
@ -140,7 +142,7 @@ func (t *tcpGROTable) deleteAt(key flowKey, i int) {
// tcpGROItem represents bookkeeping data for a TCP packet during the lifetime
// of a GRO evaluation across a vector of packets.
type tcpGROItem struct {
key flowKey
key tcpFlowKey
sentSeq uint32 // the sequence number
bufsIndex uint16 // the index into the original bufs slice
numMerged uint16 // the number of packets merged into this item
@ -164,6 +166,103 @@ func (t *tcpGROTable) reset() {
}
}
// udpFlowKey represents the key for a UDP flow.
type udpFlowKey struct {
srcAddr, dstAddr [16]byte
srcPort, dstPort uint16
isV6 bool
}
// udpGROTable holds flow and coalescing information for the purposes of UDP GRO.
type udpGROTable struct {
itemsByFlow map[udpFlowKey][]udpGROItem
itemsPool [][]udpGROItem
}
func newUDPGROTable() *udpGROTable {
u := &udpGROTable{
itemsByFlow: make(map[udpFlowKey][]udpGROItem, conn.IdealBatchSize),
itemsPool: make([][]udpGROItem, conn.IdealBatchSize),
}
for i := range u.itemsPool {
u.itemsPool[i] = make([]udpGROItem, 0, conn.IdealBatchSize)
}
return u
}
func newUDPFlowKey(pkt []byte, srcAddrOffset, dstAddrOffset, udphOffset int) udpFlowKey {
key := udpFlowKey{}
addrSize := dstAddrOffset - srcAddrOffset
copy(key.srcAddr[:], pkt[srcAddrOffset:dstAddrOffset])
copy(key.dstAddr[:], pkt[dstAddrOffset:dstAddrOffset+addrSize])
key.srcPort = binary.BigEndian.Uint16(pkt[udphOffset:])
key.dstPort = binary.BigEndian.Uint16(pkt[udphOffset+2:])
key.isV6 = addrSize == 16
return key
}
// lookupOrInsert looks up a flow for the provided packet and metadata,
// returning the packets found for the flow, or inserting a new one if none
// is found.
func (u *udpGROTable) lookupOrInsert(pkt []byte, srcAddrOffset, dstAddrOffset, udphOffset, bufsIndex int) ([]udpGROItem, bool) {
key := newUDPFlowKey(pkt, srcAddrOffset, dstAddrOffset, udphOffset)
items, ok := u.itemsByFlow[key]
if ok {
return items, ok
}
// TODO: insert() performs another map lookup. This could be rearranged to avoid.
u.insert(pkt, srcAddrOffset, dstAddrOffset, udphOffset, bufsIndex, false)
return nil, false
}
// insert an item in the table for the provided packet and packet metadata.
func (u *udpGROTable) insert(pkt []byte, srcAddrOffset, dstAddrOffset, udphOffset, bufsIndex int, cSumKnownInvalid bool) {
key := newUDPFlowKey(pkt, srcAddrOffset, dstAddrOffset, udphOffset)
item := udpGROItem{
key: key,
bufsIndex: uint16(bufsIndex),
gsoSize: uint16(len(pkt[udphOffset+udphLen:])),
iphLen: uint8(udphOffset),
cSumKnownInvalid: cSumKnownInvalid,
}
items, ok := u.itemsByFlow[key]
if !ok {
items = u.newItems()
}
items = append(items, item)
u.itemsByFlow[key] = items
}
func (u *udpGROTable) updateAt(item udpGROItem, i int) {
items, _ := u.itemsByFlow[item.key]
items[i] = item
}
// udpGROItem represents bookkeeping data for a UDP packet during the lifetime
// of a GRO evaluation across a vector of packets.
type udpGROItem struct {
key udpFlowKey
bufsIndex uint16 // the index into the original bufs slice
numMerged uint16 // the number of packets merged into this item
gsoSize uint16 // payload size
iphLen uint8 // ip header len
cSumKnownInvalid bool // UDP header checksum validity; a false value DOES NOT imply valid, just unknown.
}
func (u *udpGROTable) newItems() []udpGROItem {
var items []udpGROItem
items, u.itemsPool = u.itemsPool[len(u.itemsPool)-1], u.itemsPool[:len(u.itemsPool)-1]
return items
}
func (u *udpGROTable) reset() {
for k, items := range u.itemsByFlow {
items = items[:0]
u.itemsPool = append(u.itemsPool, items)
delete(u.itemsByFlow, k)
}
}
// canCoalesce represents the outcome of checking if two TCP packets are
// candidates for coalescing.
type canCoalesce int
@ -174,6 +273,61 @@ const (
coalesceAppend canCoalesce = 1
)
// ipHeadersCanCoalesce returns true if the IP headers found in pktA and pktB
// meet all requirements to be merged as part of a GRO operation, otherwise it
// returns false.
func ipHeadersCanCoalesce(pktA, pktB []byte) bool {
if len(pktA) < 9 || len(pktB) < 9 {
return false
}
if pktA[0]>>4 == 6 {
if pktA[0] != pktB[0] || pktA[1]>>4 != pktB[1]>>4 {
// cannot coalesce with unequal Traffic class values
return false
}
if pktA[7] != pktB[7] {
// cannot coalesce with unequal Hop limit values
return false
}
} else {
if pktA[1] != pktB[1] {
// cannot coalesce with unequal ToS values
return false
}
if pktA[6]>>5 != pktB[6]>>5 {
// cannot coalesce with unequal DF or reserved bits. MF is checked
// further up the stack.
return false
}
if pktA[8] != pktB[8] {
// cannot coalesce with unequal TTL values
return false
}
}
return true
}
// udpPacketsCanCoalesce evaluates if pkt can be coalesced with the packet
// described by item. iphLen and gsoSize describe pkt. bufs is the vector of
// packets involved in the current GRO evaluation. bufsOffset is the offset at
// which packet data begins within bufs.
func udpPacketsCanCoalesce(pkt []byte, iphLen uint8, gsoSize uint16, item udpGROItem, bufs [][]byte, bufsOffset int) canCoalesce {
pktTarget := bufs[item.bufsIndex][bufsOffset:]
if !ipHeadersCanCoalesce(pkt, pktTarget) {
return coalesceUnavailable
}
if len(pktTarget[iphLen+udphLen:])%int(item.gsoSize) != 0 {
// A smaller than gsoSize packet has been appended previously.
// Nothing can come after a smaller packet on the end.
return coalesceUnavailable
}
if gsoSize > item.gsoSize {
// We cannot have a larger packet following a smaller one.
return coalesceUnavailable
}
return coalesceAppend
}
// tcpPacketsCanCoalesce evaluates if pkt can be coalesced with the packet
// described by item. This function makes considerations that match the kernel's
// GRO self tests, which can be found in tools/testing/selftests/net/gro.c.
@ -189,30 +343,9 @@ func tcpPacketsCanCoalesce(pkt []byte, iphLen, tcphLen uint8, seq uint32, pshSet
return coalesceUnavailable
}
}
if pkt[0]>>4 == 6 {
if pkt[0] != pktTarget[0] || pkt[1]>>4 != pktTarget[1]>>4 {
// cannot coalesce with unequal Traffic class values
if !ipHeadersCanCoalesce(pkt, pktTarget) {
return coalesceUnavailable
}
if pkt[7] != pktTarget[7] {
// cannot coalesce with unequal Hop limit values
return coalesceUnavailable
}
} else {
if pkt[1] != pktTarget[1] {
// cannot coalesce with unequal ToS values
return coalesceUnavailable
}
if pkt[6]>>5 != pktTarget[6]>>5 {
// cannot coalesce with unequal DF or reserved bits. MF is checked
// further up the stack.
return coalesceUnavailable
}
if pkt[8] != pktTarget[8] {
// cannot coalesce with unequal TTL values
return coalesceUnavailable
}
}
// seq adjacency
lhsLen := item.gsoSize
lhsLen += item.numMerged * item.gsoSize
@ -252,16 +385,16 @@ func tcpPacketsCanCoalesce(pkt []byte, iphLen, tcphLen uint8, seq uint32, pshSet
return coalesceUnavailable
}
func tcpChecksumValid(pkt []byte, iphLen uint8, isV6 bool) bool {
func checksumValid(pkt []byte, iphLen, proto uint8, isV6 bool) bool {
srcAddrAt := ipv4SrcAddrOffset
addrSize := 4
if isV6 {
srcAddrAt = ipv6SrcAddrOffset
addrSize = 16
}
tcpTotalLen := uint16(len(pkt) - int(iphLen))
tcpCSumNoFold := pseudoHeaderChecksumNoFold(unix.IPPROTO_TCP, pkt[srcAddrAt:srcAddrAt+addrSize], pkt[srcAddrAt+addrSize:srcAddrAt+addrSize*2], tcpTotalLen)
return ^checksum(pkt[iphLen:], tcpCSumNoFold) == 0
lenForPseudo := uint16(len(pkt) - int(iphLen))
cSum := pseudoHeaderChecksumNoFold(proto, pkt[srcAddrAt:srcAddrAt+addrSize], pkt[srcAddrAt+addrSize:srcAddrAt+addrSize*2], lenForPseudo)
return ^checksum(pkt[iphLen:], cSum) == 0
}
// coalesceResult represents the result of attempting to coalesce two TCP
@ -276,8 +409,36 @@ const (
coalesceSuccess
)
// coalesceUDPPackets attempts to coalesce pkt with the packet described by
// item, and returns the outcome.
func coalesceUDPPackets(pkt []byte, item *udpGROItem, bufs [][]byte, bufsOffset int, isV6 bool) coalesceResult {
pktHead := bufs[item.bufsIndex][bufsOffset:] // the packet that will end up at the front
headersLen := item.iphLen + udphLen
coalescedLen := len(bufs[item.bufsIndex][bufsOffset:]) + len(pkt) - int(headersLen)
if cap(pktHead)-bufsOffset < coalescedLen {
// We don't want to allocate a new underlying array if capacity is
// too small.
return coalesceInsufficientCap
}
if item.numMerged == 0 {
if item.cSumKnownInvalid || !checksumValid(bufs[item.bufsIndex][bufsOffset:], item.iphLen, unix.IPPROTO_UDP, isV6) {
return coalesceItemInvalidCSum
}
}
if !checksumValid(pkt, item.iphLen, unix.IPPROTO_UDP, isV6) {
return coalescePktInvalidCSum
}
extendBy := len(pkt) - int(headersLen)
bufs[item.bufsIndex] = append(bufs[item.bufsIndex], make([]byte, extendBy)...)
copy(bufs[item.bufsIndex][bufsOffset+len(pktHead):], pkt[headersLen:])
item.numMerged++
return coalesceSuccess
}
// coalesceTCPPackets attempts to coalesce pkt with the packet described by
// item, returning the outcome. This function may swap bufs elements in the
// item, and returns the outcome. This function may swap bufs elements in the
// event of a prepend as item's bufs index is already being tracked for writing
// to a Device.
func coalesceTCPPackets(mode canCoalesce, pkt []byte, pktBuffsIndex int, gsoSize uint16, seq uint32, pshSet bool, item *tcpGROItem, bufs [][]byte, bufsOffset int, isV6 bool) coalesceResult {
@ -297,11 +458,11 @@ func coalesceTCPPackets(mode canCoalesce, pkt []byte, pktBuffsIndex int, gsoSize
return coalescePSHEnding
}
if item.numMerged == 0 {
if !tcpChecksumValid(bufs[item.bufsIndex][bufsOffset:], item.iphLen, isV6) {
if !checksumValid(bufs[item.bufsIndex][bufsOffset:], item.iphLen, unix.IPPROTO_TCP, isV6) {
return coalesceItemInvalidCSum
}
}
if !tcpChecksumValid(pkt, item.iphLen, isV6) {
if !checksumValid(pkt, item.iphLen, unix.IPPROTO_TCP, isV6) {
return coalescePktInvalidCSum
}
item.sentSeq = seq
@ -319,11 +480,11 @@ func coalesceTCPPackets(mode canCoalesce, pkt []byte, pktBuffsIndex int, gsoSize
return coalesceInsufficientCap
}
if item.numMerged == 0 {
if !tcpChecksumValid(bufs[item.bufsIndex][bufsOffset:], item.iphLen, isV6) {
if !checksumValid(bufs[item.bufsIndex][bufsOffset:], item.iphLen, unix.IPPROTO_TCP, isV6) {
return coalesceItemInvalidCSum
}
}
if !tcpChecksumValid(pkt, item.iphLen, isV6) {
if !checksumValid(pkt, item.iphLen, unix.IPPROTO_TCP, isV6) {
return coalescePktInvalidCSum
}
if pshSet {
@ -354,52 +515,52 @@ const (
maxUint16 = 1<<16 - 1
)
type tcpGROResult int
type groResult int
const (
tcpGROResultNoop tcpGROResult = iota
tcpGROResultTableInsert
tcpGROResultCoalesced
groResultNoop groResult = iota
groResultTableInsert
groResultCoalesced
)
// tcpGRO evaluates the TCP packet at pktI in bufs for coalescing with
// existing packets tracked in table. It returns a tcpGROResultNoop when no
// action was taken, tcpGROResultTableInsert when the evaluated packet was
// inserted into table, and tcpGROResultCoalesced when the evaluated packet was
// existing packets tracked in table. It returns a groResultNoop when no
// action was taken, groResultTableInsert when the evaluated packet was
// inserted into table, and groResultCoalesced when the evaluated packet was
// coalesced with another packet in table.
func tcpGRO(bufs [][]byte, offset int, pktI int, table *tcpGROTable, isV6 bool) tcpGROResult {
func tcpGRO(bufs [][]byte, offset int, pktI int, table *tcpGROTable, isV6 bool) groResult {
pkt := bufs[pktI][offset:]
if len(pkt) > maxUint16 {
// A valid IPv4 or IPv6 packet will never exceed this.
return tcpGROResultNoop
return groResultNoop
}
iphLen := int((pkt[0] & 0x0F) * 4)
if isV6 {
iphLen = 40
ipv6HPayloadLen := int(binary.BigEndian.Uint16(pkt[4:]))
if ipv6HPayloadLen != len(pkt)-iphLen {
return tcpGROResultNoop
return groResultNoop
}
} else {
totalLen := int(binary.BigEndian.Uint16(pkt[2:]))
if totalLen != len(pkt) {
return tcpGROResultNoop
return groResultNoop
}
}
if len(pkt) < iphLen {
return tcpGROResultNoop
return groResultNoop
}
tcphLen := int((pkt[iphLen+12] >> 4) * 4)
if tcphLen < 20 || tcphLen > 60 {
return tcpGROResultNoop
return groResultNoop
}
if len(pkt) < iphLen+tcphLen {
return tcpGROResultNoop
return groResultNoop
}
if !isV6 {
if pkt[6]&ipv4FlagMoreFragments != 0 || pkt[6]<<3 != 0 || pkt[7] != 0 {
// no GRO support for fragmented segments for now
return tcpGROResultNoop
return groResultNoop
}
}
tcpFlags := pkt[iphLen+tcpFlagsOffset]
@ -407,14 +568,14 @@ func tcpGRO(bufs [][]byte, offset int, pktI int, table *tcpGROTable, isV6 bool)
// not a candidate if any non-ACK flags (except PSH+ACK) are set
if tcpFlags != tcpFlagACK {
if pkt[iphLen+tcpFlagsOffset] != tcpFlagACK|tcpFlagPSH {
return tcpGROResultNoop
return groResultNoop
}
pshSet = true
}
gsoSize := uint16(len(pkt) - tcphLen - iphLen)
// not a candidate if payload len is 0
if gsoSize < 1 {
return tcpGROResultNoop
return groResultNoop
}
seq := binary.BigEndian.Uint32(pkt[iphLen+4:])
srcAddrOffset := ipv4SrcAddrOffset
@ -425,7 +586,7 @@ func tcpGRO(bufs [][]byte, offset int, pktI int, table *tcpGROTable, isV6 bool)
}
items, existing := table.lookupOrInsert(pkt, srcAddrOffset, srcAddrOffset+addrLen, iphLen, tcphLen, pktI)
if !existing {
return tcpGROResultNoop
return groResultTableInsert
}
for i := len(items) - 1; i >= 0; i-- {
// In the best case of packets arriving in order iterating in reverse is
@ -443,54 +604,25 @@ func tcpGRO(bufs [][]byte, offset int, pktI int, table *tcpGROTable, isV6 bool)
switch result {
case coalesceSuccess:
table.updateAt(item, i)
return tcpGROResultCoalesced
return groResultCoalesced
case coalesceItemInvalidCSum:
// delete the item with an invalid csum
table.deleteAt(item.key, i)
case coalescePktInvalidCSum:
// no point in inserting an item that we can't coalesce
return tcpGROResultNoop
return groResultNoop
default:
}
}
}
// failed to coalesce with any other packets; store the item in the flow
table.insert(pkt, srcAddrOffset, srcAddrOffset+addrLen, iphLen, tcphLen, pktI)
return tcpGROResultTableInsert
return groResultTableInsert
}
func isTCP4NoIPOptions(b []byte) bool {
if len(b) < 40 {
return false
}
if b[0]>>4 != 4 {
return false
}
if b[0]&0x0F != 5 {
return false
}
if b[9] != unix.IPPROTO_TCP {
return false
}
return true
}
func isTCP6NoEH(b []byte) bool {
if len(b) < 60 {
return false
}
if b[0]>>4 != 6 {
return false
}
if b[6] != unix.IPPROTO_TCP {
return false
}
return true
}
// applyCoalesceAccounting updates bufs to account for coalescing based on the
// applyTCPCoalesceAccounting updates bufs to account for coalescing based on the
// metadata found in table.
func applyCoalesceAccounting(bufs [][]byte, offset int, table *tcpGROTable, isV6 bool) error {
func applyTCPCoalesceAccounting(bufs [][]byte, offset int, table *tcpGROTable) error {
for _, items := range table.itemsByFlow {
for _, item := range items {
if item.numMerged > 0 {
@ -505,7 +637,7 @@ func applyCoalesceAccounting(bufs [][]byte, offset int, table *tcpGROTable, isV6
// Recalculate the total len (IPv4) or payload len (IPv6).
// Recalculate the (IPv4) header checksum.
if isV6 {
if item.key.isV6 {
hdr.gsoType = unix.VIRTIO_NET_HDR_GSO_TCPV6
binary.BigEndian.PutUint16(pkt[4:], uint16(len(pkt))-uint16(item.iphLen)) // set new IPv6 header payload len
} else {
@ -525,7 +657,7 @@ func applyCoalesceAccounting(bufs [][]byte, offset int, table *tcpGROTable, isV6
// this with computation of the tcp header and payload checksum.
addrLen := 4
addrOffset := ipv4SrcAddrOffset
if isV6 {
if item.key.isV6 {
addrLen = 16
addrOffset = ipv6SrcAddrOffset
}
@ -546,54 +678,245 @@ func applyCoalesceAccounting(bufs [][]byte, offset int, table *tcpGROTable, isV6
return nil
}
// applyUDPCoalesceAccounting updates bufs to account for coalescing based on the
// metadata found in table.
func applyUDPCoalesceAccounting(bufs [][]byte, offset int, table *udpGROTable) error {
for _, items := range table.itemsByFlow {
for _, item := range items {
if item.numMerged > 0 {
hdr := virtioNetHdr{
flags: unix.VIRTIO_NET_HDR_F_NEEDS_CSUM, // this turns into CHECKSUM_PARTIAL in the skb
hdrLen: uint16(item.iphLen + udphLen),
gsoSize: item.gsoSize,
csumStart: uint16(item.iphLen),
csumOffset: 6,
}
pkt := bufs[item.bufsIndex][offset:]
// Recalculate the total len (IPv4) or payload len (IPv6).
// Recalculate the (IPv4) header checksum.
hdr.gsoType = unix.VIRTIO_NET_HDR_GSO_UDP_L4
if item.key.isV6 {
binary.BigEndian.PutUint16(pkt[4:], uint16(len(pkt))-uint16(item.iphLen)) // set new IPv6 header payload len
} else {
pkt[10], pkt[11] = 0, 0
binary.BigEndian.PutUint16(pkt[2:], uint16(len(pkt))) // set new total length
iphCSum := ^checksum(pkt[:item.iphLen], 0) // compute IPv4 header checksum
binary.BigEndian.PutUint16(pkt[10:], iphCSum) // set IPv4 header checksum field
}
err := hdr.encode(bufs[item.bufsIndex][offset-virtioNetHdrLen:])
if err != nil {
return err
}
// Recalculate the UDP len field value
binary.BigEndian.PutUint16(pkt[item.iphLen+4:], uint16(len(pkt[item.iphLen:])))
// Calculate the pseudo header checksum and place it at the UDP
// checksum offset. Downstream checksum offloading will combine
// this with computation of the udp header and payload checksum.
addrLen := 4
addrOffset := ipv4SrcAddrOffset
if item.key.isV6 {
addrLen = 16
addrOffset = ipv6SrcAddrOffset
}
srcAddrAt := offset + addrOffset
srcAddr := bufs[item.bufsIndex][srcAddrAt : srcAddrAt+addrLen]
dstAddr := bufs[item.bufsIndex][srcAddrAt+addrLen : srcAddrAt+addrLen*2]
psum := pseudoHeaderChecksumNoFold(unix.IPPROTO_UDP, srcAddr, dstAddr, uint16(len(pkt)-int(item.iphLen)))
binary.BigEndian.PutUint16(pkt[hdr.csumStart+hdr.csumOffset:], checksum([]byte{}, psum))
} else {
hdr := virtioNetHdr{}
err := hdr.encode(bufs[item.bufsIndex][offset-virtioNetHdrLen:])
if err != nil {
return err
}
}
}
}
return nil
}
type groCandidateType uint8
const (
notGROCandidate groCandidateType = iota
tcp4GROCandidate
tcp6GROCandidate
udp4GROCandidate
udp6GROCandidate
)
func packetIsGROCandidate(b []byte, canUDPGRO bool) groCandidateType {
if len(b) < 28 {
return notGROCandidate
}
if b[0]>>4 == 4 {
if b[0]&0x0F != 5 {
// IPv4 packets w/IP options do not coalesce
return notGROCandidate
}
if b[9] == unix.IPPROTO_TCP && len(b) >= 40 {
return tcp4GROCandidate
}
if b[9] == unix.IPPROTO_UDP && canUDPGRO {
return udp4GROCandidate
}
} else if b[0]>>4 == 6 {
if b[6] == unix.IPPROTO_TCP && len(b) >= 60 {
return tcp6GROCandidate
}
if b[6] == unix.IPPROTO_UDP && len(b) >= 48 && canUDPGRO {
return udp6GROCandidate
}
}
return notGROCandidate
}
const (
udphLen = 8
)
// udpGRO evaluates the UDP packet at pktI in bufs for coalescing with
// existing packets tracked in table. It returns a groResultNoop when no
// action was taken, groResultTableInsert when the evaluated packet was
// inserted into table, and groResultCoalesced when the evaluated packet was
// coalesced with another packet in table.
func udpGRO(bufs [][]byte, offset int, pktI int, table *udpGROTable, isV6 bool) groResult {
pkt := bufs[pktI][offset:]
if len(pkt) > maxUint16 {
// A valid IPv4 or IPv6 packet will never exceed this.
return groResultNoop
}
iphLen := int((pkt[0] & 0x0F) * 4)
if isV6 {
iphLen = 40
ipv6HPayloadLen := int(binary.BigEndian.Uint16(pkt[4:]))
if ipv6HPayloadLen != len(pkt)-iphLen {
return groResultNoop
}
} else {
totalLen := int(binary.BigEndian.Uint16(pkt[2:]))
if totalLen != len(pkt) {
return groResultNoop
}
}
if len(pkt) < iphLen {
return groResultNoop
}
if len(pkt) < iphLen+udphLen {
return groResultNoop
}
if !isV6 {
if pkt[6]&ipv4FlagMoreFragments != 0 || pkt[6]<<3 != 0 || pkt[7] != 0 {
// no GRO support for fragmented segments for now
return groResultNoop
}
}
gsoSize := uint16(len(pkt) - udphLen - iphLen)
// not a candidate if payload len is 0
if gsoSize < 1 {
return groResultNoop
}
srcAddrOffset := ipv4SrcAddrOffset
addrLen := 4
if isV6 {
srcAddrOffset = ipv6SrcAddrOffset
addrLen = 16
}
items, existing := table.lookupOrInsert(pkt, srcAddrOffset, srcAddrOffset+addrLen, iphLen, pktI)
if !existing {
return groResultTableInsert
}
// With UDP we only check the last item, otherwise we could reorder packets
// for a given flow. We must also always insert a new item, or successfully
// coalesce with an existing item, for the same reason.
item := items[len(items)-1]
can := udpPacketsCanCoalesce(pkt, uint8(iphLen), gsoSize, item, bufs, offset)
var pktCSumKnownInvalid bool
if can == coalesceAppend {
result := coalesceUDPPackets(pkt, &item, bufs, offset, isV6)
switch result {
case coalesceSuccess:
table.updateAt(item, len(items)-1)
return groResultCoalesced
case coalesceItemInvalidCSum:
// If the existing item has an invalid csum we take no action. A new
// item will be stored after it, and the existing item will never be
// revisited as part of future coalescing candidacy checks.
case coalescePktInvalidCSum:
// We must insert a new item, but we also mark it as invalid csum
// to prevent a repeat checksum validation.
pktCSumKnownInvalid = true
default:
}
}
// failed to coalesce with any other packets; store the item in the flow
table.insert(pkt, srcAddrOffset, srcAddrOffset+addrLen, iphLen, pktI, pktCSumKnownInvalid)
return groResultTableInsert
}
// handleGRO evaluates bufs for GRO, and writes the indices of the resulting
// packets into toWrite. toWrite, tcp4Table, and tcp6Table should initially be
// packets into toWrite. toWrite, tcpTable, and udpTable should initially be
// empty (but non-nil), and are passed in to save allocs as the caller may reset
// and recycle them across vectors of packets.
func handleGRO(bufs [][]byte, offset int, tcp4Table, tcp6Table *tcpGROTable, toWrite *[]int) error {
// and recycle them across vectors of packets. canUDPGRO indicates if UDP GRO is
// supported.
func handleGRO(bufs [][]byte, offset int, tcpTable *tcpGROTable, udpTable *udpGROTable, canUDPGRO bool, toWrite *[]int) error {
for i := range bufs {
if offset < virtioNetHdrLen || offset > len(bufs[i])-1 {
return errors.New("invalid offset")
}
var result tcpGROResult
switch {
case isTCP4NoIPOptions(bufs[i][offset:]): // ipv4 packets w/IP options do not coalesce
result = tcpGRO(bufs, offset, i, tcp4Table, false)
case isTCP6NoEH(bufs[i][offset:]): // ipv6 packets w/extension headers do not coalesce
result = tcpGRO(bufs, offset, i, tcp6Table, true)
var result groResult
switch packetIsGROCandidate(bufs[i][offset:], canUDPGRO) {
case tcp4GROCandidate:
result = tcpGRO(bufs, offset, i, tcpTable, false)
case tcp6GROCandidate:
result = tcpGRO(bufs, offset, i, tcpTable, true)
case udp4GROCandidate:
result = udpGRO(bufs, offset, i, udpTable, false)
case udp6GROCandidate:
result = udpGRO(bufs, offset, i, udpTable, true)
}
switch result {
case tcpGROResultNoop:
case groResultNoop:
hdr := virtioNetHdr{}
err := hdr.encode(bufs[i][offset-virtioNetHdrLen:])
if err != nil {
return err
}
fallthrough
case tcpGROResultTableInsert:
case groResultTableInsert:
*toWrite = append(*toWrite, i)
}
}
err4 := applyCoalesceAccounting(bufs, offset, tcp4Table, false)
err6 := applyCoalesceAccounting(bufs, offset, tcp6Table, true)
return errors.Join(err4, err6)
errTCP := applyTCPCoalesceAccounting(bufs, offset, tcpTable)
errUDP := applyUDPCoalesceAccounting(bufs, offset, udpTable)
return errors.Join(errTCP, errUDP)
}
// tcpTSO splits packets from in into outBuffs, writing the size of each
// gsoSplit splits packets from in into outBuffs, writing the size of each
// element into sizes. It returns the number of buffers populated, and/or an
// error.
func tcpTSO(in []byte, hdr virtioNetHdr, outBuffs [][]byte, sizes []int, outOffset int) (int, error) {
func gsoSplit(in []byte, hdr virtioNetHdr, outBuffs [][]byte, sizes []int, outOffset int, isV6 bool) (int, error) {
iphLen := int(hdr.csumStart)
srcAddrOffset := ipv6SrcAddrOffset
addrLen := 16
if hdr.gsoType == unix.VIRTIO_NET_HDR_GSO_TCPV4 {
if !isV6 {
in[10], in[11] = 0, 0 // clear ipv4 header checksum
srcAddrOffset = ipv4SrcAddrOffset
addrLen = 4
}
tcpCSumAt := int(hdr.csumStart + hdr.csumOffset)
in[tcpCSumAt], in[tcpCSumAt+1] = 0, 0 // clear tcp checksum
firstTCPSeqNum := binary.BigEndian.Uint32(in[hdr.csumStart+4:])
transportCsumAt := int(hdr.csumStart + hdr.csumOffset)
in[transportCsumAt], in[transportCsumAt+1] = 0, 0 // clear tcp/udp checksum
var firstTCPSeqNum uint32
var protocol uint8
if hdr.gsoType == unix.VIRTIO_NET_HDR_GSO_TCPV4 || hdr.gsoType == unix.VIRTIO_NET_HDR_GSO_TCPV6 {
protocol = unix.IPPROTO_TCP
firstTCPSeqNum = binary.BigEndian.Uint32(in[hdr.csumStart+4:])
} else {
protocol = unix.IPPROTO_UDP
}
nextSegmentDataAt := int(hdr.hdrLen)
i := 0
for ; nextSegmentDataAt < len(in); i++ {
@ -610,7 +933,7 @@ func tcpTSO(in []byte, hdr virtioNetHdr, outBuffs [][]byte, sizes []int, outOffs
out := outBuffs[i][outOffset:]
copy(out, in[:iphLen])
if hdr.gsoType == unix.VIRTIO_NET_HDR_GSO_TCPV4 {
if !isV6 {
// For IPv4 we are responsible for incrementing the ID field,
// updating the total len field, and recalculating the header
// checksum.
@ -627,8 +950,11 @@ func tcpTSO(in []byte, hdr virtioNetHdr, outBuffs [][]byte, sizes []int, outOffs
binary.BigEndian.PutUint16(out[4:], uint16(totalLen-iphLen))
}
// TCP header
// copy transport header
copy(out[hdr.csumStart:hdr.hdrLen], in[hdr.csumStart:hdr.hdrLen])
if protocol == unix.IPPROTO_TCP {
// set TCP seq and adjust TCP flags
tcpSeq := firstTCPSeqNum + uint32(hdr.gsoSize*uint16(i))
binary.BigEndian.PutUint32(out[hdr.csumStart+4:], tcpSeq)
if nextSegmentEnd != len(in) {
@ -636,16 +962,20 @@ func tcpTSO(in []byte, hdr virtioNetHdr, outBuffs [][]byte, sizes []int, outOffs
clearFlags := tcpFlagFIN | tcpFlagPSH
out[hdr.csumStart+tcpFlagsOffset] &^= clearFlags
}
} else {
// set UDP header len
binary.BigEndian.PutUint16(out[hdr.csumStart+4:], uint16(segmentDataLen)+(hdr.hdrLen-hdr.csumStart))
}
// payload
copy(out[hdr.hdrLen:], in[nextSegmentDataAt:nextSegmentEnd])
// TCP checksum
tcpHLen := int(hdr.hdrLen - hdr.csumStart)
tcpLenForPseudo := uint16(tcpHLen + segmentDataLen)
tcpCSumNoFold := pseudoHeaderChecksumNoFold(unix.IPPROTO_TCP, in[srcAddrOffset:srcAddrOffset+addrLen], in[srcAddrOffset+addrLen:srcAddrOffset+addrLen*2], tcpLenForPseudo)
tcpCSum := ^checksum(out[hdr.csumStart:totalLen], tcpCSumNoFold)
binary.BigEndian.PutUint16(out[hdr.csumStart+hdr.csumOffset:], tcpCSum)
// transport checksum
transportHeaderLen := int(hdr.hdrLen - hdr.csumStart)
lenForPseudo := uint16(transportHeaderLen + segmentDataLen)
transportCSumNoFold := pseudoHeaderChecksumNoFold(protocol, in[srcAddrOffset:srcAddrOffset+addrLen], in[srcAddrOffset+addrLen:srcAddrOffset+addrLen*2], lenForPseudo)
transportCSum := ^checksum(out[hdr.csumStart:totalLen], transportCSumNoFold)
binary.BigEndian.PutUint16(out[hdr.csumStart+hdr.csumOffset:], transportCSum)
nextSegmentDataAt += int(hdr.gsoSize)
}

752
tun/offload_linux_test.go Normal file
View File

@ -0,0 +1,752 @@
/* SPDX-License-Identifier: MIT
*
* Copyright (C) 2017-2023 WireGuard LLC. All Rights Reserved.
*/
package tun
import (
"net/netip"
"testing"
"golang.org/x/sys/unix"
"golang.zx2c4.com/wireguard/conn"
"gvisor.dev/gvisor/pkg/tcpip"
"gvisor.dev/gvisor/pkg/tcpip/header"
)
const (
offset = virtioNetHdrLen
)
var (
ip4PortA = netip.MustParseAddrPort("192.0.2.1:1")
ip4PortB = netip.MustParseAddrPort("192.0.2.2:1")
ip4PortC = netip.MustParseAddrPort("192.0.2.3:1")
ip6PortA = netip.MustParseAddrPort("[2001:db8::1]:1")
ip6PortB = netip.MustParseAddrPort("[2001:db8::2]:1")
ip6PortC = netip.MustParseAddrPort("[2001:db8::3]:1")
)
func udp4PacketMutateIPFields(srcIPPort, dstIPPort netip.AddrPort, payloadLen int, ipFn func(*header.IPv4Fields)) []byte {
totalLen := 28 + payloadLen
b := make([]byte, offset+int(totalLen), 65535)
ipv4H := header.IPv4(b[offset:])
srcAs4 := srcIPPort.Addr().As4()
dstAs4 := dstIPPort.Addr().As4()
ipFields := &header.IPv4Fields{
SrcAddr: tcpip.AddrFromSlice(srcAs4[:]),
DstAddr: tcpip.AddrFromSlice(dstAs4[:]),
Protocol: unix.IPPROTO_UDP,
TTL: 64,
TotalLength: uint16(totalLen),
}
if ipFn != nil {
ipFn(ipFields)
}
ipv4H.Encode(ipFields)
udpH := header.UDP(b[offset+20:])
udpH.Encode(&header.UDPFields{
SrcPort: srcIPPort.Port(),
DstPort: dstIPPort.Port(),
Length: uint16(payloadLen + udphLen),
})
ipv4H.SetChecksum(^ipv4H.CalculateChecksum())
pseudoCsum := header.PseudoHeaderChecksum(unix.IPPROTO_UDP, ipv4H.SourceAddress(), ipv4H.DestinationAddress(), uint16(udphLen+payloadLen))
udpH.SetChecksum(^udpH.CalculateChecksum(pseudoCsum))
return b
}
func udp6Packet(srcIPPort, dstIPPort netip.AddrPort, payloadLen int) []byte {
return udp6PacketMutateIPFields(srcIPPort, dstIPPort, payloadLen, nil)
}
func udp6PacketMutateIPFields(srcIPPort, dstIPPort netip.AddrPort, payloadLen int, ipFn func(*header.IPv6Fields)) []byte {
totalLen := 48 + payloadLen
b := make([]byte, offset+int(totalLen), 65535)
ipv6H := header.IPv6(b[offset:])
srcAs16 := srcIPPort.Addr().As16()
dstAs16 := dstIPPort.Addr().As16()
ipFields := &header.IPv6Fields{
SrcAddr: tcpip.AddrFromSlice(srcAs16[:]),
DstAddr: tcpip.AddrFromSlice(dstAs16[:]),
TransportProtocol: unix.IPPROTO_UDP,
HopLimit: 64,
PayloadLength: uint16(payloadLen + udphLen),
}
if ipFn != nil {
ipFn(ipFields)
}
ipv6H.Encode(ipFields)
udpH := header.UDP(b[offset+40:])
udpH.Encode(&header.UDPFields{
SrcPort: srcIPPort.Port(),
DstPort: dstIPPort.Port(),
Length: uint16(payloadLen + udphLen),
})
pseudoCsum := header.PseudoHeaderChecksum(unix.IPPROTO_UDP, ipv6H.SourceAddress(), ipv6H.DestinationAddress(), uint16(udphLen+payloadLen))
udpH.SetChecksum(^udpH.CalculateChecksum(pseudoCsum))
return b
}
func udp4Packet(srcIPPort, dstIPPort netip.AddrPort, payloadLen int) []byte {
return udp4PacketMutateIPFields(srcIPPort, dstIPPort, payloadLen, nil)
}
func tcp4PacketMutateIPFields(srcIPPort, dstIPPort netip.AddrPort, flags header.TCPFlags, segmentSize, seq uint32, ipFn func(*header.IPv4Fields)) []byte {
totalLen := 40 + segmentSize
b := make([]byte, offset+int(totalLen), 65535)
ipv4H := header.IPv4(b[offset:])
srcAs4 := srcIPPort.Addr().As4()
dstAs4 := dstIPPort.Addr().As4()
ipFields := &header.IPv4Fields{
SrcAddr: tcpip.AddrFromSlice(srcAs4[:]),
DstAddr: tcpip.AddrFromSlice(dstAs4[:]),
Protocol: unix.IPPROTO_TCP,
TTL: 64,
TotalLength: uint16(totalLen),
}
if ipFn != nil {
ipFn(ipFields)
}
ipv4H.Encode(ipFields)
tcpH := header.TCP(b[offset+20:])
tcpH.Encode(&header.TCPFields{
SrcPort: srcIPPort.Port(),
DstPort: dstIPPort.Port(),
SeqNum: seq,
AckNum: 1,
DataOffset: 20,
Flags: flags,
WindowSize: 3000,
})
ipv4H.SetChecksum(^ipv4H.CalculateChecksum())
pseudoCsum := header.PseudoHeaderChecksum(unix.IPPROTO_TCP, ipv4H.SourceAddress(), ipv4H.DestinationAddress(), uint16(20+segmentSize))
tcpH.SetChecksum(^tcpH.CalculateChecksum(pseudoCsum))
return b
}
func tcp4Packet(srcIPPort, dstIPPort netip.AddrPort, flags header.TCPFlags, segmentSize, seq uint32) []byte {
return tcp4PacketMutateIPFields(srcIPPort, dstIPPort, flags, segmentSize, seq, nil)
}
func tcp6PacketMutateIPFields(srcIPPort, dstIPPort netip.AddrPort, flags header.TCPFlags, segmentSize, seq uint32, ipFn func(*header.IPv6Fields)) []byte {
totalLen := 60 + segmentSize
b := make([]byte, offset+int(totalLen), 65535)
ipv6H := header.IPv6(b[offset:])
srcAs16 := srcIPPort.Addr().As16()
dstAs16 := dstIPPort.Addr().As16()
ipFields := &header.IPv6Fields{
SrcAddr: tcpip.AddrFromSlice(srcAs16[:]),
DstAddr: tcpip.AddrFromSlice(dstAs16[:]),
TransportProtocol: unix.IPPROTO_TCP,
HopLimit: 64,
PayloadLength: uint16(segmentSize + 20),
}
if ipFn != nil {
ipFn(ipFields)
}
ipv6H.Encode(ipFields)
tcpH := header.TCP(b[offset+40:])
tcpH.Encode(&header.TCPFields{
SrcPort: srcIPPort.Port(),
DstPort: dstIPPort.Port(),
SeqNum: seq,
AckNum: 1,
DataOffset: 20,
Flags: flags,
WindowSize: 3000,
})
pseudoCsum := header.PseudoHeaderChecksum(unix.IPPROTO_TCP, ipv6H.SourceAddress(), ipv6H.DestinationAddress(), uint16(20+segmentSize))
tcpH.SetChecksum(^tcpH.CalculateChecksum(pseudoCsum))
return b
}
func tcp6Packet(srcIPPort, dstIPPort netip.AddrPort, flags header.TCPFlags, segmentSize, seq uint32) []byte {
return tcp6PacketMutateIPFields(srcIPPort, dstIPPort, flags, segmentSize, seq, nil)
}
func Test_handleVirtioRead(t *testing.T) {
tests := []struct {
name string
hdr virtioNetHdr
pktIn []byte
wantLens []int
wantErr bool
}{
{
"tcp4",
virtioNetHdr{
flags: unix.VIRTIO_NET_HDR_F_NEEDS_CSUM,
gsoType: unix.VIRTIO_NET_HDR_GSO_TCPV4,
gsoSize: 100,
hdrLen: 40,
csumStart: 20,
csumOffset: 16,
},
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck|header.TCPFlagPsh, 200, 1),
[]int{140, 140},
false,
},
{
"tcp6",
virtioNetHdr{
flags: unix.VIRTIO_NET_HDR_F_NEEDS_CSUM,
gsoType: unix.VIRTIO_NET_HDR_GSO_TCPV6,
gsoSize: 100,
hdrLen: 60,
csumStart: 40,
csumOffset: 16,
},
tcp6Packet(ip6PortA, ip6PortB, header.TCPFlagAck|header.TCPFlagPsh, 200, 1),
[]int{160, 160},
false,
},
{
"udp4",
virtioNetHdr{
flags: unix.VIRTIO_NET_HDR_F_NEEDS_CSUM,
gsoType: unix.VIRTIO_NET_HDR_GSO_UDP_L4,
gsoSize: 100,
hdrLen: 28,
csumStart: 20,
csumOffset: 6,
},
udp4Packet(ip4PortA, ip4PortB, 200),
[]int{128, 128},
false,
},
{
"udp6",
virtioNetHdr{
flags: unix.VIRTIO_NET_HDR_F_NEEDS_CSUM,
gsoType: unix.VIRTIO_NET_HDR_GSO_UDP_L4,
gsoSize: 100,
hdrLen: 48,
csumStart: 40,
csumOffset: 6,
},
udp6Packet(ip6PortA, ip6PortB, 200),
[]int{148, 148},
false,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
out := make([][]byte, conn.IdealBatchSize)
sizes := make([]int, conn.IdealBatchSize)
for i := range out {
out[i] = make([]byte, 65535)
}
tt.hdr.encode(tt.pktIn)
n, err := handleVirtioRead(tt.pktIn, out, sizes, offset)
if err != nil {
if tt.wantErr {
return
}
t.Fatalf("got err: %v", err)
}
if n != len(tt.wantLens) {
t.Fatalf("got %d packets, wanted %d", n, len(tt.wantLens))
}
for i := range tt.wantLens {
if tt.wantLens[i] != sizes[i] {
t.Fatalf("wantLens[%d]: %d != outSizes: %d", i, tt.wantLens[i], sizes[i])
}
}
})
}
}
func flipTCP4Checksum(b []byte) []byte {
at := virtioNetHdrLen + 20 + 16 // 20 byte ipv4 header; tcp csum offset is 16
b[at] ^= 0xFF
b[at+1] ^= 0xFF
return b
}
func flipUDP4Checksum(b []byte) []byte {
at := virtioNetHdrLen + 20 + 6 // 20 byte ipv4 header; udp csum offset is 6
b[at] ^= 0xFF
b[at+1] ^= 0xFF
return b
}
func Fuzz_handleGRO(f *testing.F) {
pkt0 := tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 1)
pkt1 := tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 101)
pkt2 := tcp4Packet(ip4PortA, ip4PortC, header.TCPFlagAck, 100, 201)
pkt3 := tcp6Packet(ip6PortA, ip6PortB, header.TCPFlagAck, 100, 1)
pkt4 := tcp6Packet(ip6PortA, ip6PortB, header.TCPFlagAck, 100, 101)
pkt5 := tcp6Packet(ip6PortA, ip6PortC, header.TCPFlagAck, 100, 201)
pkt6 := udp4Packet(ip4PortA, ip4PortB, 100)
pkt7 := udp4Packet(ip4PortA, ip4PortB, 100)
pkt8 := udp4Packet(ip4PortA, ip4PortC, 100)
pkt9 := udp6Packet(ip6PortA, ip6PortB, 100)
pkt10 := udp6Packet(ip6PortA, ip6PortB, 100)
pkt11 := udp6Packet(ip6PortA, ip6PortC, 100)
f.Add(pkt0, pkt1, pkt2, pkt3, pkt4, pkt5, pkt6, pkt7, pkt8, pkt9, pkt10, pkt11, true, offset)
f.Fuzz(func(t *testing.T, pkt0, pkt1, pkt2, pkt3, pkt4, pkt5, pkt6, pkt7, pkt8, pkt9, pkt10, pkt11 []byte, canUDPGRO bool, offset int) {
pkts := [][]byte{pkt0, pkt1, pkt2, pkt3, pkt4, pkt5, pkt6, pkt7, pkt8, pkt9, pkt10, pkt11}
toWrite := make([]int, 0, len(pkts))
handleGRO(pkts, offset, newTCPGROTable(), newUDPGROTable(), canUDPGRO, &toWrite)
if len(toWrite) > len(pkts) {
t.Errorf("len(toWrite): %d > len(pkts): %d", len(toWrite), len(pkts))
}
seenWriteI := make(map[int]bool)
for _, writeI := range toWrite {
if writeI < 0 || writeI > len(pkts)-1 {
t.Errorf("toWrite value (%d) outside bounds of len(pkts): %d", writeI, len(pkts))
}
if seenWriteI[writeI] {
t.Errorf("duplicate toWrite value: %d", writeI)
}
seenWriteI[writeI] = true
}
})
}
func Test_handleGRO(t *testing.T) {
tests := []struct {
name string
pktsIn [][]byte
canUDPGRO bool
wantToWrite []int
wantLens []int
wantErr bool
}{
{
"multiple protocols and flows",
[][]byte{
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 1), // tcp4 flow 1
udp4Packet(ip4PortA, ip4PortB, 100), // udp4 flow 1
udp4Packet(ip4PortA, ip4PortC, 100), // udp4 flow 2
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 101), // tcp4 flow 1
tcp4Packet(ip4PortA, ip4PortC, header.TCPFlagAck, 100, 201), // tcp4 flow 2
tcp6Packet(ip6PortA, ip6PortB, header.TCPFlagAck, 100, 1), // tcp6 flow 1
tcp6Packet(ip6PortA, ip6PortB, header.TCPFlagAck, 100, 101), // tcp6 flow 1
tcp6Packet(ip6PortA, ip6PortC, header.TCPFlagAck, 100, 201), // tcp6 flow 2
udp4Packet(ip4PortA, ip4PortB, 100), // udp4 flow 1
udp6Packet(ip6PortA, ip6PortB, 100), // udp6 flow 1
udp6Packet(ip6PortA, ip6PortB, 100), // udp6 flow 1
},
true,
[]int{0, 1, 2, 4, 5, 7, 9},
[]int{240, 228, 128, 140, 260, 160, 248},
false,
},
{
"multiple protocols and flows no UDP GRO",
[][]byte{
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 1), // tcp4 flow 1
udp4Packet(ip4PortA, ip4PortB, 100), // udp4 flow 1
udp4Packet(ip4PortA, ip4PortC, 100), // udp4 flow 2
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 101), // tcp4 flow 1
tcp4Packet(ip4PortA, ip4PortC, header.TCPFlagAck, 100, 201), // tcp4 flow 2
tcp6Packet(ip6PortA, ip6PortB, header.TCPFlagAck, 100, 1), // tcp6 flow 1
tcp6Packet(ip6PortA, ip6PortB, header.TCPFlagAck, 100, 101), // tcp6 flow 1
tcp6Packet(ip6PortA, ip6PortC, header.TCPFlagAck, 100, 201), // tcp6 flow 2
udp4Packet(ip4PortA, ip4PortB, 100), // udp4 flow 1
udp6Packet(ip6PortA, ip6PortB, 100), // udp6 flow 1
udp6Packet(ip6PortA, ip6PortB, 100), // udp6 flow 1
},
false,
[]int{0, 1, 2, 4, 5, 7, 8, 9, 10},
[]int{240, 128, 128, 140, 260, 160, 128, 148, 148},
false,
},
{
"PSH interleaved",
[][]byte{
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 1), // v4 flow 1
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck|header.TCPFlagPsh, 100, 101), // v4 flow 1
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 201), // v4 flow 1
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 301), // v4 flow 1
tcp6Packet(ip6PortA, ip6PortB, header.TCPFlagAck, 100, 1), // v6 flow 1
tcp6Packet(ip6PortA, ip6PortB, header.TCPFlagAck|header.TCPFlagPsh, 100, 101), // v6 flow 1
tcp6Packet(ip6PortA, ip6PortB, header.TCPFlagAck, 100, 201), // v6 flow 1
tcp6Packet(ip6PortA, ip6PortB, header.TCPFlagAck, 100, 301), // v6 flow 1
},
true,
[]int{0, 2, 4, 6},
[]int{240, 240, 260, 260},
false,
},
{
"coalesceItemInvalidCSum",
[][]byte{
flipTCP4Checksum(tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 1)), // v4 flow 1 seq 1 len 100
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 101), // v4 flow 1 seq 101 len 100
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 201), // v4 flow 1 seq 201 len 100
flipUDP4Checksum(udp4Packet(ip4PortA, ip4PortB, 100)),
udp4Packet(ip4PortA, ip4PortB, 100),
udp4Packet(ip4PortA, ip4PortB, 100),
},
true,
[]int{0, 1, 3, 4},
[]int{140, 240, 128, 228},
false,
},
{
"out of order",
[][]byte{
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 101), // v4 flow 1 seq 101 len 100
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 1), // v4 flow 1 seq 1 len 100
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 201), // v4 flow 1 seq 201 len 100
},
true,
[]int{0},
[]int{340},
false,
},
{
"unequal TTL",
[][]byte{
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 1),
tcp4PacketMutateIPFields(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 101, func(fields *header.IPv4Fields) {
fields.TTL++
}),
udp4Packet(ip4PortA, ip4PortB, 100),
udp4PacketMutateIPFields(ip4PortA, ip4PortB, 100, func(fields *header.IPv4Fields) {
fields.TTL++
}),
},
true,
[]int{0, 1, 2, 3},
[]int{140, 140, 128, 128},
false,
},
{
"unequal ToS",
[][]byte{
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 1),
tcp4PacketMutateIPFields(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 101, func(fields *header.IPv4Fields) {
fields.TOS++
}),
udp4Packet(ip4PortA, ip4PortB, 100),
udp4PacketMutateIPFields(ip4PortA, ip4PortB, 100, func(fields *header.IPv4Fields) {
fields.TOS++
}),
},
true,
[]int{0, 1, 2, 3},
[]int{140, 140, 128, 128},
false,
},
{
"unequal flags more fragments set",
[][]byte{
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 1),
tcp4PacketMutateIPFields(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 101, func(fields *header.IPv4Fields) {
fields.Flags = 1
}),
udp4Packet(ip4PortA, ip4PortB, 100),
udp4PacketMutateIPFields(ip4PortA, ip4PortB, 100, func(fields *header.IPv4Fields) {
fields.Flags = 1
}),
},
true,
[]int{0, 1, 2, 3},
[]int{140, 140, 128, 128},
false,
},
{
"unequal flags DF set",
[][]byte{
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 1),
tcp4PacketMutateIPFields(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 101, func(fields *header.IPv4Fields) {
fields.Flags = 2
}),
udp4Packet(ip4PortA, ip4PortB, 100),
udp4PacketMutateIPFields(ip4PortA, ip4PortB, 100, func(fields *header.IPv4Fields) {
fields.Flags = 2
}),
},
true,
[]int{0, 1, 2, 3},
[]int{140, 140, 128, 128},
false,
},
{
"ipv6 unequal hop limit",
[][]byte{
tcp6Packet(ip6PortA, ip6PortB, header.TCPFlagAck, 100, 1),
tcp6PacketMutateIPFields(ip6PortA, ip6PortB, header.TCPFlagAck, 100, 101, func(fields *header.IPv6Fields) {
fields.HopLimit++
}),
udp6Packet(ip6PortA, ip6PortB, 100),
udp6PacketMutateIPFields(ip6PortA, ip6PortB, 100, func(fields *header.IPv6Fields) {
fields.HopLimit++
}),
},
true,
[]int{0, 1, 2, 3},
[]int{160, 160, 148, 148},
false,
},
{
"ipv6 unequal traffic class",
[][]byte{
tcp6Packet(ip6PortA, ip6PortB, header.TCPFlagAck, 100, 1),
tcp6PacketMutateIPFields(ip6PortA, ip6PortB, header.TCPFlagAck, 100, 101, func(fields *header.IPv6Fields) {
fields.TrafficClass++
}),
udp6Packet(ip6PortA, ip6PortB, 100),
udp6PacketMutateIPFields(ip6PortA, ip6PortB, 100, func(fields *header.IPv6Fields) {
fields.TrafficClass++
}),
},
true,
[]int{0, 1, 2, 3},
[]int{160, 160, 148, 148},
false,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
toWrite := make([]int, 0, len(tt.pktsIn))
err := handleGRO(tt.pktsIn, offset, newTCPGROTable(), newUDPGROTable(), tt.canUDPGRO, &toWrite)
if err != nil {
if tt.wantErr {
return
}
t.Fatalf("got err: %v", err)
}
if len(toWrite) != len(tt.wantToWrite) {
t.Fatalf("got %d packets, wanted %d", len(toWrite), len(tt.wantToWrite))
}
for i, pktI := range tt.wantToWrite {
if tt.wantToWrite[i] != toWrite[i] {
t.Fatalf("wantToWrite[%d]: %d != toWrite: %d", i, tt.wantToWrite[i], toWrite[i])
}
if tt.wantLens[i] != len(tt.pktsIn[pktI][offset:]) {
t.Errorf("wanted len %d packet at %d, got: %d", tt.wantLens[i], i, len(tt.pktsIn[pktI][offset:]))
}
}
})
}
}
func Test_packetIsGROCandidate(t *testing.T) {
tcp4 := tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 1)[virtioNetHdrLen:]
tcp4TooShort := tcp4[:39]
ip4InvalidHeaderLen := make([]byte, len(tcp4))
copy(ip4InvalidHeaderLen, tcp4)
ip4InvalidHeaderLen[0] = 0x46
ip4InvalidProtocol := make([]byte, len(tcp4))
copy(ip4InvalidProtocol, tcp4)
ip4InvalidProtocol[9] = unix.IPPROTO_GRE
tcp6 := tcp6Packet(ip6PortA, ip6PortB, header.TCPFlagAck, 100, 1)[virtioNetHdrLen:]
tcp6TooShort := tcp6[:59]
ip6InvalidProtocol := make([]byte, len(tcp6))
copy(ip6InvalidProtocol, tcp6)
ip6InvalidProtocol[6] = unix.IPPROTO_GRE
udp4 := udp4Packet(ip4PortA, ip4PortB, 100)[virtioNetHdrLen:]
udp4TooShort := udp4[:27]
udp6 := udp6Packet(ip6PortA, ip6PortB, 100)[virtioNetHdrLen:]
udp6TooShort := udp6[:47]
tests := []struct {
name string
b []byte
canUDPGRO bool
want groCandidateType
}{
{
"tcp4",
tcp4,
true,
tcp4GROCandidate,
},
{
"tcp6",
tcp6,
true,
tcp6GROCandidate,
},
{
"udp4",
udp4,
true,
udp4GROCandidate,
},
{
"udp4 no support",
udp4,
false,
notGROCandidate,
},
{
"udp6",
udp6,
true,
udp6GROCandidate,
},
{
"udp6 no support",
udp6,
false,
notGROCandidate,
},
{
"udp4 too short",
udp4TooShort,
true,
notGROCandidate,
},
{
"udp6 too short",
udp6TooShort,
true,
notGROCandidate,
},
{
"tcp4 too short",
tcp4TooShort,
true,
notGROCandidate,
},
{
"tcp6 too short",
tcp6TooShort,
true,
notGROCandidate,
},
{
"invalid IP version",
[]byte{0x00},
true,
notGROCandidate,
},
{
"invalid IP header len",
ip4InvalidHeaderLen,
true,
notGROCandidate,
},
{
"ip4 invalid protocol",
ip4InvalidProtocol,
true,
notGROCandidate,
},
{
"ip6 invalid protocol",
ip6InvalidProtocol,
true,
notGROCandidate,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
if got := packetIsGROCandidate(tt.b, tt.canUDPGRO); got != tt.want {
t.Errorf("packetIsGROCandidate() = %v, want %v", got, tt.want)
}
})
}
}
func Test_udpPacketsCanCoalesce(t *testing.T) {
udp4a := udp4Packet(ip4PortA, ip4PortB, 100)
udp4b := udp4Packet(ip4PortA, ip4PortB, 100)
udp4c := udp4Packet(ip4PortA, ip4PortB, 110)
type args struct {
pkt []byte
iphLen uint8
gsoSize uint16
item udpGROItem
bufs [][]byte
bufsOffset int
}
tests := []struct {
name string
args args
want canCoalesce
}{
{
"coalesceAppend equal gso",
args{
pkt: udp4a[offset:],
iphLen: 20,
gsoSize: 100,
item: udpGROItem{
gsoSize: 100,
iphLen: 20,
},
bufs: [][]byte{
udp4a,
udp4b,
},
bufsOffset: offset,
},
coalesceAppend,
},
{
"coalesceAppend smaller gso",
args{
pkt: udp4a[offset : len(udp4a)-90],
iphLen: 20,
gsoSize: 10,
item: udpGROItem{
gsoSize: 100,
iphLen: 20,
},
bufs: [][]byte{
udp4a,
udp4b,
},
bufsOffset: offset,
},
coalesceAppend,
},
{
"coalesceUnavailable smaller gso previously appended",
args{
pkt: udp4a[offset:],
iphLen: 20,
gsoSize: 100,
item: udpGROItem{
gsoSize: 100,
iphLen: 20,
},
bufs: [][]byte{
udp4c,
udp4b,
},
bufsOffset: offset,
},
coalesceUnavailable,
},
{
"coalesceUnavailable larger following smaller",
args{
pkt: udp4c[offset:],
iphLen: 20,
gsoSize: 110,
item: udpGROItem{
gsoSize: 100,
iphLen: 20,
},
bufs: [][]byte{
udp4a,
udp4c,
},
bufsOffset: offset,
},
coalesceUnavailable,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
if got := udpPacketsCanCoalesce(tt.args.pkt, tt.args.iphLen, tt.args.gsoSize, tt.args.item, tt.args.bufs, tt.args.bufsOffset); got != tt.want {
t.Errorf("udpPacketsCanCoalesce() = %v, want %v", got, tt.want)
}
})
}
}

411
tun/tcp_offload_linux_test.go
View File

@ -1,411 +0,0 @@
/* SPDX-License-Identifier: MIT
*
* Copyright (C) 2017-2023 WireGuard LLC. All Rights Reserved.
*/
package tun
import (
"net/netip"
"testing"
"golang.org/x/sys/unix"
"golang.zx2c4.com/wireguard/conn"
"gvisor.dev/gvisor/pkg/tcpip"
"gvisor.dev/gvisor/pkg/tcpip/header"
)
const (
offset = virtioNetHdrLen
)
var (
ip4PortA = netip.MustParseAddrPort("192.0.2.1:1")
ip4PortB = netip.MustParseAddrPort("192.0.2.2:1")
ip4PortC = netip.MustParseAddrPort("192.0.2.3:1")
ip6PortA = netip.MustParseAddrPort("[2001:db8::1]:1")
ip6PortB = netip.MustParseAddrPort("[2001:db8::2]:1")
ip6PortC = netip.MustParseAddrPort("[2001:db8::3]:1")
)
func tcp4PacketMutateIPFields(srcIPPort, dstIPPort netip.AddrPort, flags header.TCPFlags, segmentSize, seq uint32, ipFn func(*header.IPv4Fields)) []byte {
totalLen := 40 + segmentSize
b := make([]byte, offset+int(totalLen), 65535)
ipv4H := header.IPv4(b[offset:])
srcAs4 := srcIPPort.Addr().As4()
dstAs4 := dstIPPort.Addr().As4()
ipFields := &header.IPv4Fields{
SrcAddr: tcpip.AddrFromSlice(srcAs4[:]),
DstAddr: tcpip.AddrFromSlice(dstAs4[:]),
Protocol: unix.IPPROTO_TCP,
TTL: 64,
TotalLength: uint16(totalLen),
}
if ipFn != nil {
ipFn(ipFields)
}
ipv4H.Encode(ipFields)
tcpH := header.TCP(b[offset+20:])
tcpH.Encode(&header.TCPFields{
SrcPort: srcIPPort.Port(),
DstPort: dstIPPort.Port(),
SeqNum: seq,
AckNum: 1,
DataOffset: 20,
Flags: flags,
WindowSize: 3000,
})
ipv4H.SetChecksum(^ipv4H.CalculateChecksum())
pseudoCsum := header.PseudoHeaderChecksum(unix.IPPROTO_TCP, ipv4H.SourceAddress(), ipv4H.DestinationAddress(), uint16(20+segmentSize))
tcpH.SetChecksum(^tcpH.CalculateChecksum(pseudoCsum))
return b
}
func tcp4Packet(srcIPPort, dstIPPort netip.AddrPort, flags header.TCPFlags, segmentSize, seq uint32) []byte {
return tcp4PacketMutateIPFields(srcIPPort, dstIPPort, flags, segmentSize, seq, nil)
}
func tcp6PacketMutateIPFields(srcIPPort, dstIPPort netip.AddrPort, flags header.TCPFlags, segmentSize, seq uint32, ipFn func(*header.IPv6Fields)) []byte {
totalLen := 60 + segmentSize
b := make([]byte, offset+int(totalLen), 65535)
ipv6H := header.IPv6(b[offset:])
srcAs16 := srcIPPort.Addr().As16()
dstAs16 := dstIPPort.Addr().As16()
ipFields := &header.IPv6Fields{
SrcAddr: tcpip.AddrFromSlice(srcAs16[:]),
DstAddr: tcpip.AddrFromSlice(dstAs16[:]),
TransportProtocol: unix.IPPROTO_TCP,
HopLimit: 64,
PayloadLength: uint16(segmentSize + 20),
}
if ipFn != nil {
ipFn(ipFields)
}
ipv6H.Encode(ipFields)
tcpH := header.TCP(b[offset+40:])
tcpH.Encode(&header.TCPFields{
SrcPort: srcIPPort.Port(),
DstPort: dstIPPort.Port(),
SeqNum: seq,
AckNum: 1,
DataOffset: 20,
Flags: flags,
WindowSize: 3000,
})
pseudoCsum := header.PseudoHeaderChecksum(unix.IPPROTO_TCP, ipv6H.SourceAddress(), ipv6H.DestinationAddress(), uint16(20+segmentSize))
tcpH.SetChecksum(^tcpH.CalculateChecksum(pseudoCsum))
return b
}
func tcp6Packet(srcIPPort, dstIPPort netip.AddrPort, flags header.TCPFlags, segmentSize, seq uint32) []byte {
return tcp6PacketMutateIPFields(srcIPPort, dstIPPort, flags, segmentSize, seq, nil)
}
func Test_handleVirtioRead(t *testing.T) {
tests := []struct {
name string
hdr virtioNetHdr
pktIn []byte
wantLens []int
wantErr bool
}{
{
"tcp4",
virtioNetHdr{
flags: unix.VIRTIO_NET_HDR_F_NEEDS_CSUM,
gsoType: unix.VIRTIO_NET_HDR_GSO_TCPV4,
gsoSize: 100,
hdrLen: 40,
csumStart: 20,
csumOffset: 16,
},
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck|header.TCPFlagPsh, 200, 1),
[]int{140, 140},
false,
},
{
"tcp6",
virtioNetHdr{
flags: unix.VIRTIO_NET_HDR_F_NEEDS_CSUM,
gsoType: unix.VIRTIO_NET_HDR_GSO_TCPV6,
gsoSize: 100,
hdrLen: 60,
csumStart: 40,
csumOffset: 16,
},
tcp6Packet(ip6PortA, ip6PortB, header.TCPFlagAck|header.TCPFlagPsh, 200, 1),
[]int{160, 160},
false,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
out := make([][]byte, conn.IdealBatchSize)
sizes := make([]int, conn.IdealBatchSize)
for i := range out {
out[i] = make([]byte, 65535)
}
tt.hdr.encode(tt.pktIn)
n, err := handleVirtioRead(tt.pktIn, out, sizes, offset)
if err != nil {
if tt.wantErr {
return
}
t.Fatalf("got err: %v", err)
}
if n != len(tt.wantLens) {
t.Fatalf("got %d packets, wanted %d", n, len(tt.wantLens))
}
for i := range tt.wantLens {
if tt.wantLens[i] != sizes[i] {
t.Fatalf("wantLens[%d]: %d != outSizes: %d", i, tt.wantLens[i], sizes[i])
}
}
})
}
}
func flipTCP4Checksum(b []byte) []byte {
at := virtioNetHdrLen + 20 + 16 // 20 byte ipv4 header; tcp csum offset is 16
b[at] ^= 0xFF
b[at+1] ^= 0xFF
return b
}
func Fuzz_handleGRO(f *testing.F) {
pkt0 := tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 1)
pkt1 := tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 101)
pkt2 := tcp4Packet(ip4PortA, ip4PortC, header.TCPFlagAck, 100, 201)
pkt3 := tcp6Packet(ip6PortA, ip6PortB, header.TCPFlagAck, 100, 1)
pkt4 := tcp6Packet(ip6PortA, ip6PortB, header.TCPFlagAck, 100, 101)
pkt5 := tcp6Packet(ip6PortA, ip6PortC, header.TCPFlagAck, 100, 201)
f.Add(pkt0, pkt1, pkt2, pkt3, pkt4, pkt5, offset)
f.Fuzz(func(t *testing.T, pkt0, pkt1, pkt2, pkt3, pkt4, pkt5 []byte, offset int) {
pkts := [][]byte{pkt0, pkt1, pkt2, pkt3, pkt4, pkt5}
toWrite := make([]int, 0, len(pkts))
handleGRO(pkts, offset, newTCPGROTable(), newTCPGROTable(), &toWrite)
if len(toWrite) > len(pkts) {
t.Errorf("len(toWrite): %d > len(pkts): %d", len(toWrite), len(pkts))
}
seenWriteI := make(map[int]bool)
for _, writeI := range toWrite {
if writeI < 0 || writeI > len(pkts)-1 {
t.Errorf("toWrite value (%d) outside bounds of len(pkts): %d", writeI, len(pkts))
}
if seenWriteI[writeI] {
t.Errorf("duplicate toWrite value: %d", writeI)
}
seenWriteI[writeI] = true
}
})
}
func Test_handleGRO(t *testing.T) {
tests := []struct {
name string
pktsIn [][]byte
wantToWrite []int
wantLens []int
wantErr bool
}{
{
"multiple flows",
[][]byte{
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 1), // v4 flow 1
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 101), // v4 flow 1
tcp4Packet(ip4PortA, ip4PortC, header.TCPFlagAck, 100, 201), // v4 flow 2
tcp6Packet(ip6PortA, ip6PortB, header.TCPFlagAck, 100, 1), // v6 flow 1
tcp6Packet(ip6PortA, ip6PortB, header.TCPFlagAck, 100, 101), // v6 flow 1
tcp6Packet(ip6PortA, ip6PortC, header.TCPFlagAck, 100, 201), // v6 flow 2
},
[]int{0, 2, 3, 5},
[]int{240, 140, 260, 160},
false,
},
{
"PSH interleaved",
[][]byte{
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 1), // v4 flow 1
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck|header.TCPFlagPsh, 100, 101), // v4 flow 1
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 201), // v4 flow 1
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 301), // v4 flow 1
tcp6Packet(ip6PortA, ip6PortB, header.TCPFlagAck, 100, 1), // v6 flow 1
tcp6Packet(ip6PortA, ip6PortB, header.TCPFlagAck|header.TCPFlagPsh, 100, 101), // v6 flow 1
tcp6Packet(ip6PortA, ip6PortB, header.TCPFlagAck, 100, 201), // v6 flow 1
tcp6Packet(ip6PortA, ip6PortB, header.TCPFlagAck, 100, 301), // v6 flow 1
},
[]int{0, 2, 4, 6},
[]int{240, 240, 260, 260},
false,
},
{
"coalesceItemInvalidCSum",
[][]byte{
flipTCP4Checksum(tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 1)), // v4 flow 1 seq 1 len 100
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 101), // v4 flow 1 seq 101 len 100
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 201), // v4 flow 1 seq 201 len 100
},
[]int{0, 1},
[]int{140, 240},
false,
},
{
"out of order",
[][]byte{
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 101), // v4 flow 1 seq 101 len 100
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 1), // v4 flow 1 seq 1 len 100
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 201), // v4 flow 1 seq 201 len 100
},
[]int{0},
[]int{340},
false,
},
{
"tcp4 unequal TTL",
[][]byte{
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 1),
tcp4PacketMutateIPFields(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 101, func(fields *header.IPv4Fields) {
fields.TTL++
}),
},
[]int{0, 1},
[]int{140, 140},
false,
},
{
"tcp4 unequal ToS",
[][]byte{
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 1),
tcp4PacketMutateIPFields(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 101, func(fields *header.IPv4Fields) {
fields.TOS++
}),
},
[]int{0, 1},
[]int{140, 140},
false,
},
{
"tcp4 unequal flags more fragments set",
[][]byte{
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 1),
tcp4PacketMutateIPFields(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 101, func(fields *header.IPv4Fields) {
fields.Flags = 1
}),
},
[]int{0, 1},
[]int{140, 140},
false,
},
{
"tcp4 unequal flags DF set",
[][]byte{
tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 1),
tcp4PacketMutateIPFields(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 101, func(fields *header.IPv4Fields) {
fields.Flags = 2
}),
},
[]int{0, 1},
[]int{140, 140},
false,
},
{
"tcp6 unequal hop limit",
[][]byte{
tcp6Packet(ip6PortA, ip6PortB, header.TCPFlagAck, 100, 1),
tcp6PacketMutateIPFields(ip6PortA, ip6PortB, header.TCPFlagAck, 100, 101, func(fields *header.IPv6Fields) {
fields.HopLimit++
}),
},
[]int{0, 1},
[]int{160, 160},
false,
},
{
"tcp6 unequal traffic class",
[][]byte{
tcp6Packet(ip6PortA, ip6PortB, header.TCPFlagAck, 100, 1),
tcp6PacketMutateIPFields(ip6PortA, ip6PortB, header.TCPFlagAck, 100, 101, func(fields *header.IPv6Fields) {
fields.TrafficClass++
}),
},
[]int{0, 1},
[]int{160, 160},
false,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
toWrite := make([]int, 0, len(tt.pktsIn))
err := handleGRO(tt.pktsIn, offset, newTCPGROTable(), newTCPGROTable(), &toWrite)
if err != nil {
if tt.wantErr {
return
}
t.Fatalf("got err: %v", err)
}
if len(toWrite) != len(tt.wantToWrite) {
t.Fatalf("got %d packets, wanted %d", len(toWrite), len(tt.wantToWrite))
}
for i, pktI := range tt.wantToWrite {
if tt.wantToWrite[i] != toWrite[i] {
t.Fatalf("wantToWrite[%d]: %d != toWrite: %d", i, tt.wantToWrite[i], toWrite[i])
}
if tt.wantLens[i] != len(tt.pktsIn[pktI][offset:]) {
t.Errorf("wanted len %d packet at %d, got: %d", tt.wantLens[i], i, len(tt.pktsIn[pktI][offset:]))
}
}
})
}
}
func Test_isTCP4NoIPOptions(t *testing.T) {
valid := tcp4Packet(ip4PortA, ip4PortB, header.TCPFlagAck, 100, 1)[virtioNetHdrLen:]
invalidLen := valid[:39]
invalidHeaderLen := make([]byte, len(valid))
copy(invalidHeaderLen, valid)
invalidHeaderLen[0] = 0x46
invalidProtocol := make([]byte, len(valid))
copy(invalidProtocol, valid)
invalidProtocol[9] = unix.IPPROTO_TCP + 1
tests := []struct {
name string
b []byte
want bool
}{
{
"valid",
valid,
true,
},
{
"invalid length",
invalidLen,
false,
},
{
"invalid version",
[]byte{0x00},
false,
},
{
"invalid header len",
invalidHeaderLen,
false,
},
{
"invalid protocol",
invalidProtocol,
false,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
if got := isTCP4NoIPOptions(tt.b); got != tt.want {
t.Errorf("isTCP4NoIPOptions() = %v, want %v", got, tt.want)
}
})
}
}

8
tun/testdata/fuzz/Fuzz_handleGRO/032aec0105f26f709c118365e4830d6dc087cab24cd1e154c2e790589a309b77 vendored
View File

@ -1,8 +0,0 @@
go test fuzz v1
[]byte("0")
[]byte("0")
[]byte("0")
[]byte("0")
[]byte("0")
[]byte("0")
int(34)

8
tun/testdata/fuzz/Fuzz_handleGRO/0da283f9a2098dec30d1c86784411a8ce2e8e03aa3384105e581f2c67494700d vendored
View File

@ -1,8 +0,0 @@
go test fuzz v1
[]byte("0")
[]byte("0")
[]byte("0")
[]byte("0")
[]byte("0")
[]byte("0")
int(-48)

51
tun/tun_linux.go
View File

@ -38,6 +38,7 @@ type NativeTun struct {
statusListenersShutdown chan struct{}
batchSize int
vnetHdr bool
udpGSO bool
closeOnce sync.Once
@ -48,9 +49,10 @@ type NativeTun struct {
readOpMu sync.Mutex // readOpMu guards readBuff
readBuff [virtioNetHdrLen + 65535]byte // if vnetHdr every read() is prefixed by virtioNetHdr
writeOpMu sync.Mutex // writeOpMu guards toWrite, tcp4GROTable, tcp6GROTable
writeOpMu sync.Mutex // writeOpMu guards toWrite, tcpGROTable
toWrite []int
tcp4GROTable, tcp6GROTable *tcpGROTable
tcpGROTable *tcpGROTable
udpGROTable *udpGROTable
}
func (tun *NativeTun) File() *os.File {
@ -333,8 +335,8 @@ func (tun *NativeTun) nameSlow() (string, error) {
func (tun *NativeTun) Write(bufs [][]byte, offset int) (int, error) {
tun.writeOpMu.Lock()
defer func() {
tun.tcp4GROTable.reset()
tun.tcp6GROTable.reset()
tun.tcpGROTable.reset()
tun.udpGROTable.reset()
tun.writeOpMu.Unlock()
}()
var (
@ -343,7 +345,7 @@ func (tun *NativeTun) Write(bufs [][]byte, offset int) (int, error) {
)
tun.toWrite = tun.toWrite[:0]
if tun.vnetHdr {
err := handleGRO(bufs, offset, tun.tcp4GROTable, tun.tcp6GROTable, &tun.toWrite)
err := handleGRO(bufs, offset, tun.tcpGROTable, tun.udpGROTable, tun.udpGSO, &tun.toWrite)
if err != nil {
return 0, err
}
@ -394,37 +396,42 @@ func handleVirtioRead(in []byte, bufs [][]byte, sizes []int, offset int) (int, e
sizes[0] = n
return 1, nil
}
if hdr.gsoType != unix.VIRTIO_NET_HDR_GSO_TCPV4 && hdr.gsoType != unix.VIRTIO_NET_HDR_GSO_TCPV6 {
if hdr.gsoType != unix.VIRTIO_NET_HDR_GSO_TCPV4 && hdr.gsoType != unix.VIRTIO_NET_HDR_GSO_TCPV6 && hdr.gsoType != unix.VIRTIO_NET_HDR_GSO_UDP_L4 {
return 0, fmt.Errorf("unsupported virtio GSO type: %d", hdr.gsoType)
}
ipVersion := in[0] >> 4
switch ipVersion {
case 4:
if hdr.gsoType != unix.VIRTIO_NET_HDR_GSO_TCPV4 {
if hdr.gsoType != unix.VIRTIO_NET_HDR_GSO_TCPV4 && hdr.gsoType != unix.VIRTIO_NET_HDR_GSO_UDP_L4 {
return 0, fmt.Errorf("ip header version: %d, GSO type: %d", ipVersion, hdr.gsoType)
}
case 6:
if hdr.gsoType != unix.VIRTIO_NET_HDR_GSO_TCPV6 {
if hdr.gsoType != unix.VIRTIO_NET_HDR_GSO_TCPV6 && hdr.gsoType != unix.VIRTIO_NET_HDR_GSO_UDP_L4 {
return 0, fmt.Errorf("ip header version: %d, GSO type: %d", ipVersion, hdr.gsoType)
}
default:
return 0, fmt.Errorf("invalid ip header version: %d", ipVersion)
}
// Don't trust hdr.hdrLen from the kernel as it can be equal to the length
// of the entire first packet when the kernel is handling it as part of a
// FORWARD path. Instead, parse the transport header length and add it onto
// csumStart, which is synonymous for IP header length.
if hdr.gsoType == unix.VIRTIO_NET_HDR_GSO_UDP_L4 {
hdr.hdrLen = hdr.csumStart + 8
} else {
if len(in) <= int(hdr.csumStart+12) {
return 0, errors.New("packet is too short")
}
// Don't trust hdr.hdrLen from the kernel as it can be equal to the length
// of the entire first packet when the kernel is handling it as part of a
// FORWARD path. Instead, parse the TCP header length and add it onto
// csumStart, which is synonymous for IP header length.
tcpHLen := uint16(in[hdr.csumStart+12] >> 4 * 4)
if tcpHLen < 20 || tcpHLen > 60 {
// A TCP header must be between 20 and 60 bytes in length.
return 0, fmt.Errorf("tcp header len is invalid: %d", tcpHLen)
}
hdr.hdrLen = hdr.csumStart + tcpHLen
}
if len(in) < int(hdr.hdrLen) {
return 0, fmt.Errorf("length of packet (%d) < virtioNetHdr.hdrLen (%d)", len(in), hdr.hdrLen)
@ -438,7 +445,7 @@ func handleVirtioRead(in []byte, bufs [][]byte, sizes []int, offset int) (int, e
return 0, fmt.Errorf("end of checksum offset (%d) exceeds packet length (%d)", cSumAt+1, len(in))
}
return tcpTSO(in, hdr, bufs, sizes, offset)
return gsoSplit(in, hdr, bufs, sizes, offset, ipVersion == 6)
}
func (tun *NativeTun) Read(bufs [][]byte, sizes []int, offset int) (int, error) {
@ -497,7 +504,8 @@ func (tun *NativeTun) BatchSize() int {
const (
// TODO: support TSO with ECN bits
tunOffloads = unix.TUN_F_CSUM | unix.TUN_F_TSO4 | unix.TUN_F_TSO6
tunTCPOffloads = unix.TUN_F_CSUM | unix.TUN_F_TSO4 | unix.TUN_F_TSO6
tunUDPOffloads = unix.TUN_F_USO4 | unix.TUN_F_USO6
)
func (tun *NativeTun) initFromFlags(name string) error {
@ -519,12 +527,17 @@ func (tun *NativeTun) initFromFlags(name string) error {
}
got := ifr.Uint16()
if got&unix.IFF_VNET_HDR != 0 {
err = unix.IoctlSetInt(int(fd), unix.TUNSETOFFLOAD, tunOffloads)
// tunTCPOffloads were added in Linux v2.6. We require their support
// if IFF_VNET_HDR is set.
err = unix.IoctlSetInt(int(fd), unix.TUNSETOFFLOAD, tunTCPOffloads)
if err != nil {
return
}
tun.vnetHdr = true
tun.batchSize = conn.IdealBatchSize
// tunUDPOffloads were added in Linux v6.2. We do not return an
// error if they are unsupported at runtime.
tun.udpGSO = unix.IoctlSetInt(int(fd), unix.TUNSETOFFLOAD, tunTCPOffloads|tunUDPOffloads) == nil
} else {
tun.batchSize = 1
}
@ -575,8 +588,8 @@ func CreateTUNFromFile(file *os.File, mtu int) (Device, error) {
events: make(chan Event, 5),
errors: make(chan error, 5),
statusListenersShutdown: make(chan struct{}),
tcp4GROTable: newTCPGROTable(),
tcp6GROTable: newTCPGROTable(),
tcpGROTable: newTCPGROTable(),
udpGROTable: newUDPGROTable(),
toWrite: make([]int, 0, conn.IdealBatchSize),
}
@ -631,8 +644,8 @@ func CreateUnmonitoredTUNFromFD(fd int) (Device, string, error) {
tunFile: file,
events: make(chan Event, 5),
errors: make(chan error, 5),
tcp4GROTable: newTCPGROTable(),
tcp6GROTable: newTCPGROTable(),
tcpGROTable: newTCPGROTable(),
udpGROTable: newUDPGROTable(),
toWrite: make([]int, 0, conn.IdealBatchSize),
}
name, err := tun.Name()