linux/drivers/firewire
Stefan Richter e9300a4b7b firewire: net: fix fragmented datagram_size off-by-one
RFC 2734 defines the datagram_size field in fragment encapsulation
headers thus:

    datagram_size:  The encoded size of the entire IP datagram.  The
    value of datagram_size [...] SHALL be one less than the value of
    Total Length in the datagram's IP header (see STD 5, RFC 791).

Accordingly, the eth1394 driver of Linux 2.6.36 and older set and got
this field with a -/+1 offset:

    ether1394_tx() /* transmit */
        ether1394_encapsulate_prep()
            hdr->ff.dg_size = dg_size - 1;

    ether1394_data_handler() /* receive */
        if (hdr->common.lf == ETH1394_HDR_LF_FF)
            dg_size = hdr->ff.dg_size + 1;
        else
            dg_size = hdr->sf.dg_size + 1;

Likewise, I observe OS X 10.4 and Windows XP Pro SP3 to transmit 1500
byte sized datagrams in fragments with datagram_size=1499 if link
fragmentation is required.

Only firewire-net sets and gets datagram_size without this offset.  The
result is lacking interoperability of firewire-net with OS X, Windows
XP, and presumably Linux' eth1394.  (I did not test with the latter.)
For example, FTP data transfers to a Linux firewire-net box with max_rec
smaller than the 1500 bytes MTU
  - from OS X fail entirely,
  - from Win XP start out with a bunch of fragmented datagrams which
    time out, then continue with unfragmented datagrams because Win XP
    temporarily reduces the MTU to 576 bytes.

So let's fix firewire-net's datagram_size accessors.

Note that firewire-net thereby loses interoperability with unpatched
firewire-net, but only if link fragmentation is employed.  (This happens
with large broadcast datagrams, and with large datagrams on several
FireWire CardBus cards with smaller max_rec than equivalent PCI cards,
and it can be worked around by setting a small enough MTU.)

Cc: stable@vger.kernel.org
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2016-11-03 14:46:39 +01:00
..
core-card.c IEEE 1394 (FireWire) subsystem updates post v3.4: 2012-05-24 12:57:47 -07:00
core-cdev.c firewire: use in_compat_syscall to check ioctl compatness 2016-03-22 15:36:02 -07:00
core-device.c firewire: core: document fw_csr_string's truncation of long strings 2014-12-10 20:53:02 +01:00
core-iso.c firewire: core: fix multichannel IR with buffers larger than 2 GB 2012-06-17 19:35:26 +02:00
core-topology.c Remove all #inclusions of asm/system.h 2012-03-28 18:30:03 +01:00
core-transaction.c firewire: core: use correct vendor/model IDs 2015-02-02 21:56:03 +01:00
core.h sound updates for 3.16-rc1 2014-06-04 09:08:25 -07:00
init_ohci1394_dma.c various: Fix spelling of "asynchronous" in comments. 2012-11-19 14:32:13 +01:00
Kconfig firewire: IEEE 1394 (FireWire) support should depend on HAS_DMA 2014-07-13 20:53:25 +02:00
Makefile ieee1394: move init_ohci1394_dma to drivers/firewire/ 2010-10-11 14:48:03 +02:00
net.c firewire: net: fix fragmented datagram_size off-by-one 2016-11-03 14:46:39 +01:00
nosy-user.h firewire: nosy: endianess fixes and annotations 2010-07-27 11:04:11 +02:00
nosy.c firewire: nosy: do not ignore errors in ioremap_nocache() 2016-10-09 11:38:11 +02:00
nosy.h firewire: nosy: misc cleanups 2010-07-27 11:04:10 +02:00
ohci.c firewire: ohci: propagate return code from soft_reset to probe and resume 2015-11-05 14:25:31 +01:00
ohci.h firewire: ohci: fix TI TSB82AA2 regression since 2.6.35 2010-10-17 14:09:12 +02:00
sbp2.c scsi: Do not set cmd_per_lun to 1 in the host template 2015-05-31 18:06:28 -07:00