From 66ebb6575f929a389d3c929977ed5e31d706fcfe Mon Sep 17 00:00:00 2001 From: Bhasker Hariharan Date: Thu, 7 Nov 2019 09:45:26 -0800 Subject: Add support for TIME_WAIT timeout. This change adds explicit support for honoring the 2MSL timeout for sockets in TIME_WAIT state. It also adds support for the TCP_LINGER2 option that allows modification of the FIN_WAIT2 state timeout duration for a given socket. It also adds an option to modify the Stack wide TIME_WAIT timeout but this is only for testing. On Linux this is fixed at 60s. Further, we also now correctly process RST's in CLOSE_WAIT and close the socket similar to linux without moving it to error state. We also now handle SYN in ESTABLISHED state as per RFC5961#section-4.1. Earlier we would just drop these SYNs. Which can result in some tests that pass on linux to fail on gVisor. Netstack now honors TIME_WAIT correctly as well as handles the following cases correctly. - TCP RSTs in TIME_WAIT are ignored. - A duplicate TCP FIN during TIME_WAIT extends the TIME_WAIT and a dup ACK is sent in response to the FIN as the dup FIN indicates potential loss of the original final ACK. - An out of order segment during TIME_WAIT generates a dup ACK. - A new SYN w/ a sequence number > the highest sequence number in the previous connection closes the TIME_WAIT early and opens a new connection. Further to make the SYN case work correctly the ISN (Initial Sequence Number) generation for Netstack has been updated to be as per RFC. Its not a pure random number anymore and follows the recommendation in https://tools.ietf.org/html/rfc6528#page-3. The current hash used is not a cryptographically secure hash function. A separate change will update the hash function used to Siphash similar to what is used in Linux. PiperOrigin-RevId: 279106406 --- pkg/tcpip/tcpip.go | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) (limited to 'pkg/tcpip/tcpip.go') diff --git a/pkg/tcpip/tcpip.go b/pkg/tcpip/tcpip.go index 3edb513d4..bd5eb89ca 100644 --- a/pkg/tcpip/tcpip.go +++ b/pkg/tcpip/tcpip.go @@ -586,6 +586,16 @@ type MaxSegOption int // A zero value indicates the default. type TTLOption uint8 +// TCPLingerTimeoutOption is used by SetSockOpt/GetSockOpt to set/get the +// maximum duration for which a socket lingers in the TCP_FIN_WAIT_2 state +// before being marked closed. +type TCPLingerTimeoutOption time.Duration + +// TCPTimeWaitTimeoutOption is used by SetSockOpt/GetSockOpt to set/get the +// maximum duration for which a socket lingers in the TIME_WAIT state +// before being marked closed. +type TCPTimeWaitTimeoutOption time.Duration + // MulticastTTLOption is used by SetSockOpt/GetSockOpt to control the default // TTL value for multicast messages. The default is 1. type MulticastTTLOption uint8 @@ -1329,8 +1339,8 @@ var ( // GetDanglingEndpoints returns all dangling endpoints. func GetDanglingEndpoints() []Endpoint { - es := make([]Endpoint, 0, len(danglingEndpoints)) danglingEndpointsMu.Lock() + es := make([]Endpoint, 0, len(danglingEndpoints)) for e := range danglingEndpoints { es = append(es, e) } -- cgit v1.2.3