There are many more places in OVS where using these types would be an
improvement, but the flow code is particularly confusing because it uses
a mix of byte orders.
When userspace and the kernel were using the same structure for flows,
flow_t was a useful way to indicate that a structure was really a userspace
flow instead of a kernel one, but now it's better to just write "struct
flow" for consistency, since OVS doesn't use typedefs for structs
elsewhere.
Acked-by: Jesse Gross <jesse@nicira.com>
The "struct odp_flow_key" used in the kernel datapath is conceptually
separate from the "flow_t" used in userspace, but until now we have
used the latter as a typedef for the former for convenience. This commit
separates them. This makes it possible in upcoming commits to change
them independently.
This is cross-ported from the "wdp" branch, which has had it for months.
Some of the flow actions that modify skbuff data did not check that the
skbuff was long enough before doing so. This commit fixes that problem.
Previously, the strategy for avoiding this was to only indicate the layer-3
nw_proto field in the flow if the corresponding layer-4 header was fully
present, so that if, for example, nw_proto was IPPROTO_TCP, this meant
that a TCP header was present. The original motivation for this patch was
to add corresponding code to only indicate a layer-2 dl_type if the
corresponding layer-3 header was fully present. But I'm now convinced that
this approach is conceptually wrong, because the meaning of a layer-N
header should not be affected by the meaning of a layer-(N+1) header.
This commit switches to a new approach. Now, when a header is missing, its
fields in the flow are simply zeroed and have no effect on the "type" field
for the outer header. Responsibility for ensuring that a header is fully
present is now shifted to the actions that wish to modify that header.
Signed-off-by: Ben Pfaff <blp@nicira.com>
The kernel and user datapaths have code that assumes that 802.1Q headers
are used only inside Ethernet II frames, not inside SNAP-encapsulated
frames. But the kernel and user flow_extract() implementations would
interpret 802.1Q headers inside SNAP headers as being valid VLANs. This
would cause packet corruption if any VLAN-related actions were to be taken,
so change the two flow_extract() implementations only to accept 802.1Q as
an Ethernet II frame type, not as a SNAP-encoded frame type.
802.1Q-2005 says that this is correct anyhow:
Where the ISS instance used to transmit and receive tagged frames is
provided by a media access control method that can support Ethernet
Type encoding directly (e.g., is an IEEE 802.3 or IEEE 802.11 MAC) or
is media access method independent (e.g., 6.6), the TPID is Ethernet
Type encoded, i.e., is two octets in length and comprises solely the
assigned Ethernet Type value.
Where the ISS instance is provided by a media access method that
cannot directly support Ethernet Type encoding (e.g., is an IEEE
802.5 or FDDI MAC), the TPID is encoded according to the rule for
a Subnetwork Access Protocol (Clause 10 of IEEE Std 802) that
encapsulates Ethernet frames over LLC, and comprises the SNAP
header (AA-AA-03) followed by the SNAP PID (00-00-00) followed by
the two octets of the assigned Ethernet Type value.
All of the media that OVS handles supports Ethernet Type fields, so to me
that means that we don't have to handle 802.1Q-inside-SNAP.
On the other hand, we *do* have to handle SNAP-inside-802.1Q, because this
is actually allowed by the standards. So this commit also adds that
support.
I verified that, with this change, both SNAP and Ethernet packets are
properly recognized both with and without 802.1Q encapsulation.
I was a bit surprised to find out that Linux does not accept
SNAP-encapsulated IP frames on Ethernet.
Here's a summary of how frames are handled before and after this commit:
Common cases
------------
Ethernet
+------------+
1. |dst|src|TYPE|
+------------+
Ethernet LLC SNAP
+------------+ +--------+ +-----------+
2. |dst|src| len| |aa|aa|03| |000000|TYPE|
+------------+ +--------+ +-----------+
Ethernet 802.1Q
+------------+ +---------+
3. |dst|src|8100| |VLAN|TYPE|
+------------+ +---------+
Ethernet 802.1Q LLC SNAP
+------------+ +---------+ +--------+ +-----------+
4. |dst|src|8100| |VLAN| LEN| |aa|aa|03| |000000|TYPE|
+------------+ +---------+ +--------+ +-----------+
Unusual cases
-------------
Ethernet LLC SNAP 802.1Q
+------------+ +--------+ +-----------+ +---------+
5. |dst|src| len| |aa|aa|03| |000000|8100| |VLAN|TYPE|
+------------+ +--------+ +-----------+ +---------+
Ethernet LLC
+------------+ +--------+
6. |dst|src| len| |xx|xx|xx|
+------------+ +--------+
Ethernet LLC SNAP
+------------+ +--------+ +-----------+
7. |dst|src| len| |aa|aa|03| |xxxxxx|xxxx|
+------------+ +--------+ +-----------+
Ethernet 802.1Q LLC
+------------+ +---------+ +--------+
8. |dst|src|8100| |VLAN| LEN| |xx|xx|xx|
+------------+ +---------+ +--------+
Ethernet 802.1Q LLC SNAP
+------------+ +---------+ +--------+ +-----------+
9. |dst|src|8100| |VLAN| LEN| |aa|aa|03| |xxxxxx|xxxx|
+------------+ +---------+ +--------+ +-----------+
Behavior
--------
--------------- --------------- -------------------------------------
Before After
this commit this commit
dl_type dl_vlan dl_type dl_vlan Notes
------- ------- ------- ------- -------------------------------------
1. TYPE ffff TYPE ffff no change
2. TYPE ffff TYPE ffff no change
3. TYPE VLAN TYPE VLAN no change
4. LEN VLAN TYPE VLAN proposal fixes behavior
5. TYPE VLAN 8100 ffff 802.1Q says this is invalid framing
6. 05ff ffff 05ff ffff no change
7. 05ff ffff 05ff ffff no change
8. LEN VLAN 05ff VLAN proposal fixes behavior
9. LEN VLAN 05ff VLAN proposal fixes behavior
Signed-off-by: Ben Pfaff <blp@nicira.com>
Originally, the datapath didn't care about IP TOS at all. Then, to support
NetFlow, we made it keep track of the last-seen IP TOS value on a per-flow
basis. Then, to support OpenFlow 1.0, we added a nw_tos field to
odp_flow_key. We don't need both methods, so this commit drops the
NetFlow-specific tracking.
This introduces a small kernel ABI break: upgrading the kernel module
without upgrading the OVS userspace will mean that NetFlow records will
all show an IP TOS value of 0. I don't consider that to be a serious
problem.
Adding a macro to define the vlog module in use adds a level of
indirection, which makes it easier to change how the vlog module must be
defined. A followup commit needs to do that, so getting these widespread
changes out of the way first should make that commit easier to review.
Normally match fields are zeroed if they are wildcarded in
normalize_match(). However, tun_id isn't part of struct ofp_match
so do it when we convert to a flow instead.
OpenFlow provides the ability to delete flows that match a "strict"
description. This means that wildcards are not active, and thus will
only match a single flow that exactly matches the description. The code
that checks for a match is pretty dumb and still compares the values of
fields that are wildcarded. A recent change added a "tun_id" matching
field, but did not zero out the field when it was supposed to be
ignored, which broke the matching used by strict deletions. This sets
the field regardless of whether the field is wildcarded or not.
Reported-by: Natasha Gude <natasha@nicira.com>
Bug #2775
Add a tun_id field which contains the ID of the encapsulating tunnel
on which a packet was received (0 if not received on a tunnel). Also
add an action which allows the tunnel ID to be set for outgoing
packets. At this point there aren't any tunnel implementations so
these fields don't have any effect.
The matching is exposed to OpenFlow by overloading the high 32 bits
of the cookie as the tunnel ID. ovs-ofctl is capable of turning
on this special behavior using a new "tun-cookie" command but this
command is intentially undocumented to avoid it being used without
a full understanding of the consequences.
OpenFlow 1.0 adds support for matching on IP ToS/DSCP bits.
NOTE: OVS at this point is not wire-compatible with OpenFlow 1.0 until
the final commit in this OpenFlow 1.0 set.
The OpenFlow 1.0 specification supports matching the IP address and
opcode in ARP messages. The datapath already supports this, so this
commit merely exposes that through the OpenFlow module.
NOTE: OVS at this point is not wire-compatible with OpenFlow 1.0
until the final commit in this OpenFlow 1.0 set.
Starting in OpenFlow 0.9, it is possible to match on the VLAN PCP
(priority) field and rewrite the IP ToS/DSCP bits. This check-in
provides that support and bumps the wire protocol number to 0x98.
NOTE: The wire changes come together over the set of OpenFlow 0.9 commits,
so OVS will not be OpenFlow-compatible with any official release between
this commit and the one that completes the set.
When printing a flow, there were two references to "port": one the
interface the packet arrived on and the other the L4 ports. This could
be a bit confusing to new users looking at the output of a command such
as "ovs-ofctl dump-flows". This commit changes the incoming interface
field from "port" to "in_port".
The ability to match the IP addresses in ARP packets allows for fine-grained
control of ARP processing. Some forthcoming changes to allow in-band
control to operate over L3 requires this support if we don't want to
allow overly broad rules regarding ARPs to always be white-listed.
Unfortunately, OpenFlow does not support this sort of processing yet, so
we must treat OpenFlow ARP rules as having wildcarded those L3 fields.
