diff options
Diffstat (limited to 'pkg/tcpip/stack/stack.go')
| -rw-r--r-- | pkg/tcpip/stack/stack.go | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/pkg/tcpip/stack/stack.go b/pkg/tcpip/stack/stack.go index 6a8079823..90c2cf1be 100644 --- a/pkg/tcpip/stack/stack.go +++ b/pkg/tcpip/stack/stack.go @@ -20,10 +20,12 @@ package stack import ( + "encoding/binary" "sync" "time" "golang.org/x/time/rate" + "gvisor.dev/gvisor/pkg/rand" "gvisor.dev/gvisor/pkg/sleep" "gvisor.dev/gvisor/pkg/tcpip" "gvisor.dev/gvisor/pkg/tcpip/buffer" @@ -388,6 +390,12 @@ type Stack struct { // icmpRateLimiter is a global rate limiter for all ICMP messages generated // by the stack. icmpRateLimiter *ICMPRateLimiter + + // portSeed is a one-time random value initialized at stack startup + // and is used to seed the TCP port picking on active connections + // + // TODO(gvisor.dev/issues/940): S/R this field. + portSeed uint32 } // Options contains optional Stack configuration. @@ -440,6 +448,7 @@ func New(opts Options) *Stack { stats: opts.Stats.FillIn(), handleLocal: opts.HandleLocal, icmpRateLimiter: NewICMPRateLimiter(), + portSeed: generateRandUint32(), } // Add specified network protocols. @@ -1197,3 +1206,19 @@ func (s *Stack) SetICMPBurst(burst int) { func (s *Stack) AllowICMPMessage() bool { return s.icmpRateLimiter.Allow() } + +// PortSeed returns a 32 bit value that can be used as a seed value for port +// picking. +// +// NOTE: The seed is generated once during stack initialization only. +func (s *Stack) PortSeed() uint32 { + return s.portSeed +} + +func generateRandUint32() uint32 { + b := make([]byte, 4) + if _, err := rand.Read(b); err != nil { + panic(err) + } + return binary.LittleEndian.Uint32(b) +} |