[ovs-dev] [PATCH v2 ovn] manage ARP process locally in a DVR scenario
Numan Siddique
numans at ovn.org
Mon Mar 2 04:05:35 UTC 2020
On Thu, Feb 27, 2020 at 11:21 PM Lorenzo Bianconi
<lorenzo.bianconi at redhat.com> wrote:
>
> OVN currently performs L2 address resolution and IP buffering on the
> gw node. If the system relies on FIPs, OVN will re-inject the buffered
> IP packets on the gw node, while following packets will go though
> the localnet port on the compute node resulting in a ToR switch
> misconfiguration. This patch addresses the issue managing ARP
> and IP buffering locally if FIPs are configured on the node
>
> Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi at redhat.com>
> ---
> Changes since v1:
> - add comments
> - cosmetics
> ---
> northd/ovn-northd.8.xml | 31 ++++++++++++++++++++++++
> northd/ovn-northd.c | 52 ++++++++++++++++++++++++++++++++++++++++-
> 2 files changed, 82 insertions(+), 1 deletion(-)
>
> diff --git a/northd/ovn-northd.8.xml b/northd/ovn-northd.8.xml
> index a27dfa951..23b385377 100644
> --- a/northd/ovn-northd.8.xml
> +++ b/northd/ovn-northd.8.xml
> @@ -2405,6 +2405,37 @@ output;
> </p>
> </li>
>
> + <li>
> + <p>
> + For distributed logical routers where one of the logical router ports
> + specifies a <code>redirect-chassis</code>, a priority-400 logical
> + flow for each <code>dnat_and_snat</code> NAT rules configured.
> + These flows will allow to properly forward traffic to the external
> + connections if available and avoid sending it through the tunnel.
> + Assuming the following NAT rule has been configured:
> + </p>
> +
> + <pre>
> +external_ip = <var>A</var>;
> +external_mac = <var>B</var>;
> +logical_ip = <var>C</var>;
> + </pre>
> +
> + <p>
> + the following action will be applied:
> + </p>
> +
> + <pre>
> +ip.ttl--;
> +reg0 = <var>ip.dst</var>;
> +reg1 = <var>A</var>;
> +eth.src = <var>B</var>;
> +outport = <var>router-port</var>;
> +next;
> + </pre>
> +
> + </li>
> +
> <li>
> <p>
> IPv4 routing table. For each route to IPv4 network <var>N</var> with
> diff --git a/northd/ovn-northd.c b/northd/ovn-northd.c
> index d007ba610..53958b26b 100644
> --- a/northd/ovn-northd.c
> +++ b/northd/ovn-northd.c
> @@ -6967,6 +6967,8 @@ build_routing_policy_flow(struct hmap *lflows, struct ovn_datapath *od,
> ds_destroy(&actions);
> }
>
> +/* default logical flow prioriry for distributed routes */
> +#define DROUTE_PRIO 400
> struct parsed_route {
> struct ovs_list list_node;
> struct v46_ip prefix;
> @@ -7354,6 +7356,41 @@ build_ecmp_route_flow(struct hmap *lflows, struct ovn_datapath *od,
> ds_destroy(&actions);
> }
>
> +static void
> +add_distributed_routes(struct hmap *lflows, struct ovn_datapath *od)
> +{
> + struct ds actions = DS_EMPTY_INITIALIZER;
> + struct ds match = DS_EMPTY_INITIALIZER;
> +
> + if (!od->l3dgw_port || !od->nbr) {
> + return;
> + }
> +
> + for (size_t i = 0; i < od->nbr->n_nat; i++) {
> + const struct nbrec_nat *nat = od->nbr->nat[i];
> +
> + if (strcmp(nat->type, "dnat_and_snat") ||
> + !nat->external_mac) {
> + continue;
> + }
> +
> + bool is_ipv4 = strchr(nat->logical_ip, '.') ? true : false;
> + ds_put_format(&match, "ip%s.src == %s && is_chassis_resident(\"%s\")",
> + is_ipv4 ? "4" : "6", nat->logical_ip,
> + nat->logical_port);
> + char *prefix = is_ipv4 ? "" : "xx";
> + ds_put_format(&actions, "outport = %s; eth.src = %s; "
> + "%sreg0 = ip%s.dst; %sreg1 = %s; next;",
> + od->l3dgw_port->json_key, nat->external_mac,
> + prefix, is_ipv4 ? "4" : "6",
> + prefix, nat->external_ip);
> + ovn_lflow_add(lflows, od, S_ROUTER_IN_IP_ROUTING, DROUTE_PRIO,
> + ds_cstr(&match), ds_cstr(&actions));
> + ds_clear(&match);
> + ds_clear(&actions);
> + }
You need to ds_destroy match and actions, otherwise there'll be a memory leak,
> +}
> +
> static void
> add_route(struct hmap *lflows, const struct ovn_port *op,
> const char *lrp_addr_s, const char *network_s, int plen,
> @@ -7375,6 +7412,12 @@ add_route(struct hmap *lflows, const struct ovn_port *op,
> }
> build_route_match(op_inport, network_s, plen, is_src_route, is_ipv4,
> &match, &priority);
> + /* traffic for internal IPs of logical switch ports must me sent to
s/me/be
> + * the gw controller through the overlay tunnels
> + */
> + if (op->nbrp && !op->nbrp->n_gateway_chassis) {
> + priority += DROUTE_PRIO;
> + }
>
> struct ds actions = DS_EMPTY_INITIALIZER;
> ds_put_format(&actions, "ip.ttl--; "REG_ECMP_GROUP_ID" = 0; %sreg0 = ",
> @@ -8943,7 +8986,7 @@ build_lrouter_flows(struct hmap *datapaths, struct hmap *ports,
> nat->logical_ip,
> od->l3dgw_port->json_key);
> ovn_lflow_add_with_hint(lflows, od, S_ROUTER_IN_GW_REDIRECT,
> - 100, ds_cstr(&match), "next;",
> + 200, ds_cstr(&match), "next;",
> &nat->header_);
> }
>
> @@ -9224,6 +9267,13 @@ build_lrouter_flows(struct hmap *datapaths, struct hmap *ports,
> ovn_lflow_add(lflows, od, S_ROUTER_IN_ND_RA_RESPONSE, 0, "1", "next;");
> }
>
> + /* Logical router ingress table IP_ROUTING - IP routing for distributed
> + * logical router
> + */
> + HMAP_FOR_EACH (od, key_node, datapaths) {
> + add_distributed_routes(lflows, od);
This function gets called even for logical switches. It's better to call it as
if (od->nbr && od->l3dgw_port) {
add_distributed_routes(lflows, od);
}
Thanks
Numan
> + }
> +
> /* Logical router ingress table IP_ROUTING & IP_ROUTING_ECMP: IP Routing.
> *
> * A packet that arrives at this table is an IP packet that should be
> --
> 2.24.1
>
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