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authorgVisor bot <gvisor-bot@google.com>2021-06-09 14:57:13 -0700
committergVisor bot <gvisor-bot@google.com>2021-06-09 14:57:13 -0700
commit2e574a9904cb51119abc015aea5bc45993fa32ec (patch)
tree8a6aa1ba63c363244fff16bc7ec4facf4ec27972 /pkg
parent539fe2b61aa847dccc775455d3c67f3ebf986df8 (diff)
parent12973f6244bc84fb745f2ae9120a69ffc820ef70 (diff)
Merge pull request #6128 from kevinGC:fanout-pid
PiperOrigin-RevId: 378506076
Diffstat (limited to 'pkg')
-rw-r--r--pkg/tcpip/link/fdbased/endpoint.go14
1 files changed, 6 insertions, 8 deletions
diff --git a/pkg/tcpip/link/fdbased/endpoint.go b/pkg/tcpip/link/fdbased/endpoint.go
index bddb1d0a2..735c28da1 100644
--- a/pkg/tcpip/link/fdbased/endpoint.go
+++ b/pkg/tcpip/link/fdbased/endpoint.go
@@ -41,7 +41,6 @@ package fdbased
import (
"fmt"
- "math"
"sync/atomic"
"golang.org/x/sys/unix"
@@ -196,8 +195,12 @@ type Options struct {
// option for an FD with a fanoutID already in use by another FD for a different
// NIC will return an EINVAL.
//
+// Since fanoutID must be unique within the network namespace, we start with
+// the PID to avoid collisions. The only way to be sure of avoiding collisions
+// is to run in a new network namespace.
+//
// Must be accessed using atomic operations.
-var fanoutID int32 = 0
+var fanoutID int32 = int32(unix.Getpid())
// New creates a new fd-based endpoint.
//
@@ -292,11 +295,6 @@ func createInboundDispatcher(e *endpoint, fd int, isSocket bool, fID int32) (lin
}
switch sa.(type) {
case *unix.SockaddrLinklayer:
- // See: PACKET_FANOUT_MAX in net/packet/internal.h
- const packetFanoutMax = 1 << 16
- if fID > packetFanoutMax {
- return nil, fmt.Errorf("host fanoutID limit exceeded, fanoutID must be <= %d", math.MaxUint16)
- }
// Enable PACKET_FANOUT mode if the underlying socket is of type
// AF_PACKET. We do not enable PACKET_FANOUT_FLAG_DEFRAG as that will
// prevent gvisor from receiving fragmented packets and the host does the
@@ -317,7 +315,7 @@ func createInboundDispatcher(e *endpoint, fd int, isSocket bool, fID int32) (lin
//
// See: https://github.com/torvalds/linux/blob/7acac4b3196caee5e21fb5ea53f8bc124e6a16fc/net/packet/af_packet.c#L3881
const fanoutType = unix.PACKET_FANOUT_HASH
- fanoutArg := int(fID) | fanoutType<<16
+ fanoutArg := (int(fID) & 0xffff) | fanoutType<<16
if err := unix.SetsockoptInt(fd, unix.SOL_PACKET, unix.PACKET_FANOUT, fanoutArg); err != nil {
return nil, fmt.Errorf("failed to enable PACKET_FANOUT option: %v", err)
}