[ovs-dev] [PATCH v2] dpif-netlink: convert packet_type netlink attribute
Eric Garver
e at erig.me
Wed Jul 5 15:14:14 UTC 2017
Hi Zoltan,
On Tue, Jul 04, 2017 at 09:23:17PM +0000, Zoltán Balogh wrote:
> By introducing packet type-aware pipeline, match on ethertype was
> removed when packet type is not Ethernet. As pointed out by Eric Garver,
> this could have a side effect on the kernel datapath:
> https://patchwork.ozlabs.org/patch/782991/
>
> This patch does approach the problem from a different perspective.
> Instead of re-introducing the unconditional match on Ethernet type in all
> megaflow entries, as suggested by Eric, mapping of packet_type != PT_ETH to
> dl_type could be handled in the put_exclude_packet_type() in dpif-netlink.c.
>
> Put_exclude_packet_type() filters the packet_type netlink attribute out,
> before all attributes are sent from userspace to kernel. This commit modifies
> the put_exclude_packet_type() function to do a proper conversation and add the
> missing OVS_KEY_ATTR_ETHERTYPE attribute if it's needed.
>
> Signed-off-by: Zoltán Balogh <zoltan.balogh at ericsson.com>
> Reported-by: Eric Garver <e at erig.me>
> ---
> lib/dpif-netlink.c | 120 +++++++++++++++++++++++++++++++++++++++--------------
> 1 file changed, 90 insertions(+), 30 deletions(-)
>
> diff --git a/lib/dpif-netlink.c b/lib/dpif-netlink.c
> index 562f613..cf4e98f 100644
> --- a/lib/dpif-netlink.c
> +++ b/lib/dpif-netlink.c
> @@ -3433,34 +3433,101 @@ dpif_netlink_flow_from_ofpbuf(struct dpif_netlink_flow *flow,
> }
>
>
> +static bool
> +put_exclude_packet_type(struct ofpbuf *buf, uint16_t type,
> + const struct nlattr *data, uint16_t data_len,
> + const struct nlattr *packet_type)
> +{
> + ovs_assert(NLA_ALIGN(packet_type->nla_len) == NL_A_U32_SIZE);
> + size_t packet_type_len = NL_A_U32_SIZE;
> + size_t first_chunk_size = (uint8_t *)packet_type - (uint8_t *)data;
> + size_t second_chunk_size = data_len - first_chunk_size
> + - packet_type_len;
> + uint8_t *first_attr = NULL;
> + struct nlattr *next_attr = nl_attr_next(packet_type);
> +
> + bool ethernet_present = nl_attr_find__(data, data_len,
> + OVS_KEY_ATTR_ETHERNET);
> +
> + first_attr = nl_msg_put_unspec_uninit(buf, type,
> + data_len - packet_type_len);
> + memcpy(first_attr, data, first_chunk_size);
> + memcpy(first_attr + first_chunk_size, next_attr, second_chunk_size);
> +
> + return ethernet_present;
> +}
> +
> /*
> - * If PACKET_TYPE attribute is present in 'data', it filters PACKET_TYPE out,
> - * then puts 'data' to 'buf'.
> + * If PACKET_TYPE attribute is present in 'data', converts it to ETHERNET and
> + * ETHERTYPE attributes, then puts 'data' to 'buf'.
> */
> static void
> -put_exclude_packet_type(struct ofpbuf *buf, uint16_t type,
> - const struct nlattr *data, uint16_t data_len)
> +put_convert_packet_type(struct ofpbuf *buf,
> + const struct dpif_netlink_flow *flow)
> {
> const struct nlattr *packet_type;
> + const struct nlattr *data = flow->key;
> + uint16_t data_len = flow->key_len;
> + const struct nlattr *mask_data = flow->mask;
> + uint16_t mask_len = flow->mask_len;
> + ovs_be32 value = htonl(PT_ETH);
> + bool ethernet_present = false;
> +
> + /* Verify KEY attributes. */
> + if (data_len) {
> + packet_type = nl_attr_find__(data, data_len, OVS_KEY_ATTR_PACKET_TYPE);
> + if (packet_type) {
> + /* Convert PACKET_TYPE Netlink attribute. */
> + value = nl_attr_get_be32(packet_type);
> + ethernet_present = put_exclude_packet_type(buf, OVS_FLOW_ATTR_KEY,
> + data, data_len,
> + packet_type);
> + /* Put OVS_KEY_ATTR_ETHERTYPE if needed. */
> + if (ntohl(value) == PT_ETH) {
> + ovs_assert(ethernet_present);
> + } else {
> + const struct nlattr *eth_type;
> + ovs_be16 ns_type = pt_ns_type_be(value);
>
> - packet_type = nl_attr_find__(data, data_len, OVS_KEY_ATTR_PACKET_TYPE);
> -
> - if (packet_type) {
> - /* exclude PACKET_TYPE Netlink attribute. */
> - ovs_assert(NLA_ALIGN(packet_type->nla_len) == NL_A_U32_SIZE);
> - size_t packet_type_len = NL_A_U32_SIZE;
> - size_t first_chunk_size = (uint8_t *)packet_type - (uint8_t *)data;
> - size_t second_chunk_size = data_len - first_chunk_size
> - - packet_type_len;
> - uint8_t *first_attr = NULL;
> - struct nlattr *next_attr = nl_attr_next(packet_type);
> -
> - first_attr = nl_msg_put_unspec_uninit(buf, type,
> - data_len - packet_type_len);
> - memcpy(first_attr, data, first_chunk_size);
> - memcpy(first_attr + first_chunk_size, next_attr, second_chunk_size);
> - } else {
> - nl_msg_put_unspec(buf, type, data, data_len);
> + ovs_assert(ethernet_present == false);
> +
> + eth_type = nl_attr_find__(data, data_len,
> + OVS_KEY_ATTR_ETHERTYPE);
> + if (eth_type) {
> + ovs_assert(nl_attr_get_be16(eth_type) == ns_type);
> + } else {
> + nl_msg_put_be16(buf, OVS_KEY_ATTR_ETHERTYPE, ns_type);
This inserts OVS_KEY_ATTR_ETHERTYPE at the top level of the message. It
needs to be inserted _inside_ the nested OVS_FLOW_ATTR_KEY.
> + }
> + }
> + } else {
> + nl_msg_put_unspec(buf, OVS_FLOW_ATTR_KEY, data, data_len);
> + }
> + }
> +
> + /* Verify MASK attributes. */
> + if (mask_len) {
> + packet_type = nl_attr_find__(mask_data, mask_len,
> + OVS_KEY_ATTR_PACKET_TYPE);
> + if (packet_type) {
> + /* Convert PACKET_TYPE Netlink attribute. */
> + ethernet_present = put_exclude_packet_type(buf, OVS_FLOW_ATTR_MASK,
> + mask_data, mask_len,
> + packet_type);
> + /* Put OVS_KEY_ATTR_ETHERTYPE if needed. */
> + if (ntohl(value) != PT_ETH) {
> + const struct nlattr *eth_type;
> +
> + ovs_assert(ethernet_present == false);
> +
> + eth_type = nl_attr_find__(mask_data, mask_len,
> + OVS_KEY_ATTR_ETHERTYPE);
> + if (!eth_type) {
> + nl_msg_put_be16(buf, OVS_KEY_ATTR_ETHERTYPE, OVS_BE16_MAX);
Same as above.
> + }
> + }
> + } else {
> + nl_msg_put_unspec(buf, OVS_FLOW_ATTR_MASK, mask_data, mask_len);
> + }
> }
> }
>
> @@ -3488,14 +3555,7 @@ dpif_netlink_flow_to_ofpbuf(const struct dpif_netlink_flow *flow,
> | OVS_UFID_F_OMIT_ACTIONS);
> }
> if (!flow->ufid_terse || !flow->ufid_present) {
> - if (flow->key_len) {
> - put_exclude_packet_type(buf, OVS_FLOW_ATTR_KEY, flow->key,
> - flow->key_len);
> - }
> - if (flow->mask_len) {
> - put_exclude_packet_type(buf, OVS_FLOW_ATTR_MASK, flow->mask,
> - flow->mask_len);
> - }
> + put_convert_packet_type(buf, flow);
> if (flow->actions || flow->actions_len) {
> nl_msg_put_unspec(buf, OVS_FLOW_ATTR_ACTIONS,
> flow->actions, flow->actions_len);
> --
> 1.9.1
>
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