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authorYOSHIFUJI Hideaki / 吉藤英明 <yoshfuji@linux-ipv6.org>2013-03-25 08:26:08 +0000
committerDavid S. Miller <davem@davemloft.net>2013-03-26 12:32:13 -0400
commit61a7839a19c157d11930fe69697a4c90884bf7c4 (patch)
treeef2dd78384873146897c376a85f283a57bd90637 /drivers/firewire
parent382c4b4090b7394d079c199ba053a378c6cd45b8 (diff)
downloadlinux-linaro-stable-61a7839a19c157d11930fe69697a4c90884bf7c4.tar.gz
firewire net: Ignore spd and max_payload advertised by ARP.
Stefan Richter <stefanr@s5r6.in-berlin.de> says: | As far as I can tell, it would be best to ignore max_rec and sspd from ARP | and NDP but keep using the respective information from firewire-core | instead (handed over by fwnet_probe()). | | Why? As I noted earlier, RFC 2734:1999 and RFC 3146:2001 were apparently | written with a too simplistic notion of IEEE 1394 bus topology, resulting | in max_rec and sspd in ARP-1394 and NDP-1394 to be useless, IMO. | | Consider a bus like this: | | A ---- B ==== C | | A, B, C are all IP-over-1394 capable nodes. ---- is an S400 cable hop, | and ==== is an S800 cable hop. | | In case of unicasts or multicasts in which node A is involved as | transmitter or receiver, as well as in case of broadcasts, the speeds | S100, S200, S400 work and speed S400 is optimal. | | In case of anything else, IOW in case of unicasts or multicasts in which | only nodes B and C are involved, the speeds S100, S200, S400, S800 work | and speed S800 is optimal. | | Clearly, node A should indicate sspd = S400 in its ARP or NDP packets. | But which sspd should nodes B and C set there? Maybe they set S400, which | would work but would waste half of the available bandwidth in the second | case. Or maybe they set S800, which is OK in the second case but would | prohibit any communication with node A if blindly taken for correct. | | On the other hand, firewire-core *always* gives us the correct and optimum | peer-to-peer speed and asynchronous packet payload, no matter how simple | or complex the bus topology is and no matter in which temporal order nodes | join the bus and are discovered. CC: Stefan Richter <stefanr@s5r6.in-berlin.de> Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/firewire')
-rw-r--r--drivers/firewire/net.c16
1 files changed, 0 insertions, 16 deletions
diff --git a/drivers/firewire/net.c b/drivers/firewire/net.c
index 72536e7fe95c..cb8aa865ff88 100644
--- a/drivers/firewire/net.c
+++ b/drivers/firewire/net.c
@@ -552,8 +552,6 @@ static int fwnet_finish_incoming_packet(struct net_device *net,
unsigned char *arp_ptr;
u64 fifo_addr;
u64 peer_guid;
- unsigned sspd;
- u16 max_payload;
struct fwnet_peer *peer;
unsigned long flags;
@@ -564,24 +562,10 @@ static int fwnet_finish_incoming_packet(struct net_device *net,
fifo_addr = (u64)get_unaligned_be16(&arp1394->fifo_hi) << 32
| get_unaligned_be32(&arp1394->fifo_lo);
- sspd = arp1394->sspd;
- /* Sanity check. OS X 10.3 PPC reportedly sends 131. */
- if (sspd > SCODE_3200) {
- dev_notice(&net->dev, "sspd %x out of range\n", sspd);
- sspd = SCODE_3200;
- }
- max_payload = fwnet_max_payload(arp1394->max_rec, sspd);
-
spin_lock_irqsave(&dev->lock, flags);
peer = fwnet_peer_find_by_guid(dev, peer_guid);
if (peer) {
peer->fifo = fifo_addr;
-
- if (peer->speed > sspd)
- peer->speed = sspd;
- if (peer->max_payload > max_payload)
- peer->max_payload = max_payload;
-
peer->ip = arp1394->sip;
}
spin_unlock_irqrestore(&dev->lock, flags);