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This commit is contained in:
JackDoan
2026-08-04 09:27:51 -05:00
parent a3eef407b2
commit d8d5ce344d
8 changed files with 283 additions and 111 deletions
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overlay/batch/udp_coalesce.go
+26 -28
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@@ -83,42 +83,40 @@ type parsedUDP struct {
payLen int
}
// parseUDPAt extracts the flow key and IP/UDP offsets for a packet the dispatcher already knows is
// UDP; ipHdrLen is the upstream-resolved L4 offset (see parseIPAt). Returns ok=false for malformed
// input or any shape that must not coalesce (IPv4 options/fragmentation, IPv6 extension headers).
func parseUDPAt(pkt []byte, ipHdrLen int) (parsedUDP, bool) {
ip, ok := parseIPAt(pkt, ipHdrLen)
// parseAt extracts the flow key and IP/UDP offsets for a packet the dispatcher already knows is
// UDP; ipHdrLen is the upstream-resolved L4 offset (see flowKey.parseIPAt). p must be zero on
// entry and is filled in place. Returns false for malformed input or any shape that must not
// coalesce (IPv4 options/fragmentation, IPv6 extension headers).
func (p *parsedUDP) parseAt(pkt []byte, ipHdrLen int) bool {
trimmed, ok := p.fk.parseIPAt(pkt, ipHdrLen)
if !ok {
return parsedUDP{}, false
return false
}
return parseUDPTail(ip)
return p.parseTail(trimmed, ipHdrLen)
}
// parseUDPTail layers the UDP-header parse on a validated IP prologue.
func parseUDPTail(ip parsedIP) (parsedUDP, bool) {
var p parsedUDP
pkt := ip.pkt
p.fk = ip.fk
p.ipHdrLen = ip.ipHdrLen
if len(pkt) < p.ipHdrLen+8 {
return p, false
// parseTail layers the UDP-header parse on a validated IP prologue. pkt is the trimmed packet;
// fk's addresses are already filled.
func (p *parsedUDP) parseTail(pkt []byte, ipHdrLen int) bool {
if len(pkt) < ipHdrLen+8 {
return false
}
p.hdrLen = p.ipHdrLen + 8
// UDP `length` field: must equal IP-derived length-of-UDP-header-plus-payload.
udpLen := int(binary.BigEndian.Uint16(pkt[p.ipHdrLen+4 : p.ipHdrLen+6]))
if udpLen < 8 || udpLen > len(pkt)-p.ipHdrLen {
return p, false
udpLen := int(binary.BigEndian.Uint16(pkt[ipHdrLen+4 : ipHdrLen+6]))
if udpLen < 8 || udpLen > len(pkt)-ipHdrLen {
return false
}
p.ipHdrLen = ipHdrLen
p.hdrLen = ipHdrLen + 8
p.payLen = udpLen - 8
p.fk.sport = binary.BigEndian.Uint16(pkt[p.ipHdrLen : p.ipHdrLen+2])
p.fk.dport = binary.BigEndian.Uint16(pkt[p.ipHdrLen+2 : p.ipHdrLen+4])
return p, true
p.fk.sport = binary.BigEndian.Uint16(pkt[ipHdrLen : ipHdrLen+2])
p.fk.dport = binary.BigEndian.Uint16(pkt[ipHdrLen+2 : ipHdrLen+4])
return true
}
// commitParsed commits one parsed UDP packet. The caller (dispatch, via parseUDPAt) supplies a
// commitParsed commits one parsed UDP packet. The caller (dispatch, via parseAt) supplies a
// valid parse so the header is not re-walked here.
func (c *UDPCoalescer) commitParsed(pkt []byte, info parsedUDP) error {
func (c *UDPCoalescer) commitParsed(pkt []byte, info *parsedUDP) error {
// A zero-length UDP datagram (length == 8) is legal and must reach the TUN, but cannot be
// coalesced. The len guard skips hashing the key when no flow is open.
if info.payLen == 0 {
@@ -198,7 +196,7 @@ func (c *UDPCoalescer) addVerbatim(pkt []byte) {
c.slots = append(c.slots, s)
}
func (c *UDPCoalescer) seed(pkt []byte, info parsedUDP) {
func (c *UDPCoalescer) seed(pkt []byte, info *parsedUDP) {
if info.hdrLen > udpCoalesceHdrCap || info.hdrLen+info.payLen > udpCoalesceBufSize {
c.addVerbatim(pkt)
return
@@ -224,7 +222,7 @@ func (c *UDPCoalescer) seed(pkt []byte, info parsedUDP) {
// canAppend reports whether info's packet extends the slot's seed.
// Kernel UDP-GSO requires every segment except possibly the last to be
// exactly gsoSize, and the last may be shorter (≤ gsoSize).
func (c *UDPCoalescer) canAppend(s *udpSlot, pkt []byte, info parsedUDP) bool {
func (c *UDPCoalescer) canAppend(s *udpSlot, pkt []byte, info *parsedUDP) bool {
if info.hdrLen != s.hdrLen {
return false
}
@@ -252,7 +250,7 @@ func (c *UDPCoalescer) canAppend(s *udpSlot, pkt []byte, info parsedUDP) bool {
// appendPayload folds info's packet into s and reports whether the chain is now closed: kernel
// UDP-GSO requires every segment but the last to be exactly gsoSize, so a short segment must be
// the final one. The caller must deregister a closed slot from openSlots.
func (c *UDPCoalescer) appendPayload(s *udpSlot, pkt []byte, info parsedUDP) bool {
func (c *UDPCoalescer) appendPayload(s *udpSlot, pkt []byte, info *parsedUDP) bool {
if s.numSeg == 1 {
// First append: populate hdrBuf from the seed. Deferred out of seed so solo slots, which
// flush from rawPkt, never pay the copy.