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wgengine/magicsock: retry failed single packet ops across rebinds (#6990)

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The single packet WriteTo() through RebindingUDPConn.WriteBatch() was
not checking for a rebind between loading the PacketConn and writing to
it. Same with ReadFrom()/ReadBatch().

Fixes #6989

Signed-off-by: Jordan Whited <jordan@tailscale.com>
This commit is contained in:
Jordan Whited 2023-01-20 09:15:32 -08:00 committed by GitHub
parent 6edf357b96
commit fec888581a
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GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 16 additions and 8 deletions
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24
wgengine/magicsock/magicsock.go
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@ -3258,19 +3258,23 @@ func (c *RebindingUDPConn) currentConn() nettype.PacketConn {
return c.pconn return c.pconn
} }
// ReadFrom reads a packet from c into b. func (c *RebindingUDPConn) readFromWithInitPconn(pconn nettype.PacketConn, b []byte) (int, net.Addr, error) {
// It returns the number of bytes copied and the source address.
func (c *RebindingUDPConn) ReadFrom(b []byte) (int, net.Addr, error) {
for { for {
pconn := *c.pconnAtomic.Load()
n, addr, err := pconn.ReadFrom(b) n, addr, err := pconn.ReadFrom(b)
if err != nil && pconn != c.currentConn() { if err != nil && pconn != c.currentConn() {
pconn = *c.pconnAtomic.Load()
continue continue
} }
return n, addr, err return n, addr, err
} }
} }
// ReadFrom reads a packet from c into b.
// It returns the number of bytes copied and the source address.
func (c *RebindingUDPConn) ReadFrom(b []byte) (int, net.Addr, error) {
return c.readFromWithInitPconn(*c.pconnAtomic.Load(), b)
}
// ReadFromNetaddr reads a packet from c into b. // ReadFromNetaddr reads a packet from c into b.
// It returns the number of bytes copied and the return address. // It returns the number of bytes copied and the return address.
// It is identical to c.ReadFrom, except that it returns a netip.AddrPort instead of a net.Addr. // It is identical to c.ReadFrom, except that it returns a netip.AddrPort instead of a net.Addr.
@ -3321,7 +3325,7 @@ func (c *RebindingUDPConn) WriteBatch(msgs []ipv6.Message, flags int) (int, erro
bw, ok := pconn.(batchWriter) bw, ok := pconn.(batchWriter)
if !ok { if !ok {
for _, msg := range msgs { for _, msg := range msgs {
_, err = pconn.WriteTo(msg.Buffers[0], msg.Addr) _, err = c.writeToWithInitPconn(pconn, msg.Buffers[0], msg.Addr)
if err != nil { if err != nil {
return n, err return n, err
} }
@ -3350,7 +3354,7 @@ func (c *RebindingUDPConn) ReadBatch(msgs []ipv6.Message, flags int) (int, error
br, ok := pconn.(batchReader) br, ok := pconn.(batchReader)
if !ok { if !ok {
var err error var err error
msgs[0].N, msgs[0].Addr, err = c.ReadFrom(msgs[0].Buffers[0]) msgs[0].N, msgs[0].Addr, err = c.readFromWithInitPconn(pconn, msgs[0].Buffers[0])
if err == nil { if err == nil {
return 1, nil return 1, nil
} }
@ -3398,17 +3402,21 @@ func (c *RebindingUDPConn) closeLocked() error {
return c.pconn.Close() return c.pconn.Close()
} }
func (c *RebindingUDPConn) WriteTo(b []byte, addr net.Addr) (int, error) { func (c *RebindingUDPConn) writeToWithInitPconn(pconn nettype.PacketConn, b []byte, addr net.Addr) (int, error) {
for { for {
pconn := *c.pconnAtomic.Load()
n, err := pconn.WriteTo(b, addr) n, err := pconn.WriteTo(b, addr)
if err != nil && pconn != c.currentConn() { if err != nil && pconn != c.currentConn() {
pconn = *c.pconnAtomic.Load()
continue continue
} }
return n, err return n, err
} }
} }
func (c *RebindingUDPConn) WriteTo(b []byte, addr net.Addr) (int, error) {
return c.writeToWithInitPconn(*c.pconnAtomic.Load(), b, addr)
}
func (c *RebindingUDPConn) WriteToUDPAddrPort(b []byte, addr netip.AddrPort) (int, error) { func (c *RebindingUDPConn) WriteToUDPAddrPort(b []byte, addr netip.AddrPort) (int, error) {
for { for {
pconn := *c.pconnAtomic.Load() pconn := *c.pconnAtomic.Load()