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Code Issues Releases Wiki Activity

flow: Add FLOW_WC_SEQ assertions and improve comments.

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The assertions make it easier to find all the places that need to be
updated when adding protocol support.

Acked-by: Numan Siddique <nusiddiq@redhat.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>
This commit is contained in:
Ben Pfaff 2019-03-28 09:49:01 -07:00
parent c90656d405
commit 005bb87206
2 changed files with 49 additions and 30 deletions
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64
lib/flow.c
View File

@ -626,32 +626,8 @@ parse_nsh(const void **datap, size_t *sizep, struct ovs_key_nsh *key)
return true;
}
/* Initializes 'flow' members from 'packet' and 'md', taking the packet type
* into account.
*
* Initializes the layer offsets as follows:
*
* - packet->l2_5_ofs to the
* * the start of the MPLS shim header. Can be zero, if the
* packet is of type (OFPHTN_ETHERTYPE, ETH_TYPE_MPLS).
* * UINT16_MAX when there is no MPLS shim header.
*
* - packet->l3_ofs is set to
* * zero if the packet_type is in name space OFPHTN_ETHERTYPE
* and there is no MPLS shim header.
* * just past the Ethernet header, or just past the vlan_header if
* one is present, to the first byte of the payload of the
* Ethernet frame if the packet type is Ethernet and there is
* no MPLS shim header.
* * just past the MPLS label stack to the first byte of the MPLS
* payload if there is at least one MPLS shim header.
* * UINT16_MAX if the packet type is Ethernet and the frame is
* too short to contain an Ethernet header.
*
* - packet->l4_ofs is set to just past the IPv4 or IPv6 header, if one is
* present and the packet has at least the content used for the fields
* of interest for the flow, otherwise UINT16_MAX.
*/
/* This does the same thing as miniflow_extract() with a full-size 'flow' as
* the destination. */
void
flow_extract(struct dp_packet *packet, struct flow *flow)
{
@ -730,11 +706,38 @@ ipv6_sanity_check(const struct ovs_16aligned_ip6_hdr *nh, size_t size)
return true;
}
/* Caller is responsible for initializing 'dst' with enough storage for
* FLOW_U64S * 8 bytes. */
/* Initializes 'dst' from 'packet' and 'md', taking the packet type into
* account. 'dst' must have enough space for FLOW_U64S * 8 bytes.
*
* Initializes the layer offsets as follows:
*
* - packet->l2_5_ofs to the
* * the start of the MPLS shim header. Can be zero, if the
* packet is of type (OFPHTN_ETHERTYPE, ETH_TYPE_MPLS).
* * UINT16_MAX when there is no MPLS shim header.
*
* - packet->l3_ofs is set to
* * zero if the packet_type is in name space OFPHTN_ETHERTYPE
* and there is no MPLS shim header.
* * just past the Ethernet header, or just past the vlan_header if
* one is present, to the first byte of the payload of the
* Ethernet frame if the packet type is Ethernet and there is
* no MPLS shim header.
* * just past the MPLS label stack to the first byte of the MPLS
* payload if there is at least one MPLS shim header.
* * UINT16_MAX if the packet type is Ethernet and the frame is
* too short to contain an Ethernet header.
*
* - packet->l4_ofs is set to just past the IPv4 or IPv6 header, if one is
* present and the packet has at least the content used for the fields
* of interest for the flow, otherwise UINT16_MAX.
*/
void
miniflow_extract(struct dp_packet *packet, struct miniflow *dst)
{
/* Add code to this function (or its callees) to extract new fields. */
BUILD_ASSERT_DECL(FLOW_WC_SEQ == 41);
const struct pkt_metadata *md = &packet->md;
const void *data = dp_packet_data(packet);
size_t size = dp_packet_size(packet);
@ -3182,6 +3185,11 @@ void
flow_compose(struct dp_packet *p, const struct flow *flow,
const void *l7, size_t l7_len)
{
/* Add code to this function (or its callees) for emitting new fields or
* protocols. (This isn't essential, so it can be skipped for initial
* testing.) */
BUILD_ASSERT_DECL(FLOW_WC_SEQ == 41);
uint32_t pseudo_hdr_csum;
size_t l4_len;

15
lib/odp-util.c
View File

@ -8230,14 +8230,25 @@ commit_encap_decap_action(const struct flow *flow,
* in addition to this function if needed. Sets fields in 'wc' that are
* used as part of the action.
*
* Returns a reason to force processing the flow's packets into the userspace
* slow path, if there is one, otherwise 0. */
* In the common case, this function returns 0. If the flow key modification
* requires the flow's packets to be forced into the userspace slow path, this
* function returns SLOW_ACTION. This only happens when there is no ODP action
* to modify some field that was actually modified. For example, there is no
* ODP action to modify any ARP field, so such a modification triggers
* SLOW_ACTION. (When this happens, packets that need such modification get
* flushed to userspace and handled there, which works OK but much more slowly
* than if the datapath handled it directly.) */
enum slow_path_reason
commit_odp_actions(const struct flow *flow, struct flow *base,
struct ofpbuf *odp_actions, struct flow_wildcards *wc,
bool use_masked, bool pending_encap, bool pending_decap,
struct ofpbuf *encap_data)
{
/* If you add a field that OpenFlow actions can change, and that is visible
* to the datapath (including all data fields), then you should also add
* code here to commit changes to the field. */
BUILD_ASSERT_DECL(FLOW_WC_SEQ == 41);
enum slow_path_reason slow1, slow2;
bool mpls_done = false;