OVN: add buffering support for ip packets

Add buffering support for IPv4/IPv6 packets that will be processed
by arp{}/nd_ns{} action when L2 address is not discovered yet since
otherwise the packet will be substituted with an ARP/Neighbor
Solicitation frame and this will result in the lost of the first
packet of the connection.
Moreover fix following automatic tests broken by ip-buffering support
since now original ip packets are transmitted by OVN logical
router:
- ovn -- 3 HVs, 3 LS, 3 lports/LS, 1 LR
- ovn -- /32 router IP address

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>

1 files changed, 223 insertions, 33 deletions

diff --git a/ovn/controller/pinctrl.c b/ovn/controller/pinctrl.c
index a20f6b6ef..e3ee516e4 100644
--- a/ovn/controller/pinctrl.c
+++ b/ovn/controller/pinctrl.c
@@ -61,6 +61,9 @@ static struct rconn *swconn;
  * rconn_get_connection_seqno(rconn), 'swconn' has reconnected. */
 static unsigned int conn_seq_no;
 
+static void init_buffered_packets_map(void);
+static void destroy_buffered_packets_map(void);
+
 static void pinctrl_handle_put_mac_binding(const struct flow *md,
                                            const struct flow *headers,
                                            bool is_arp);
@@ -96,6 +99,7 @@ static void pinctrl_handle_put_nd_ra_opts(
     struct ofputil_packet_in *pin, struct ofpbuf *userdata,
     struct ofpbuf *continuation);
 static void pinctrl_handle_nd_ns(const struct flow *ip_flow,
+                                 struct dp_packet *pkt_in,
                                  const struct match *md,
                                  struct ofpbuf *userdata);
 static void init_ipv6_ras(void);
@@ -108,6 +112,7 @@ static void send_ipv6_ras(
 ;
 
 COVERAGE_DEFINE(pinctrl_drop_put_mac_binding);
+COVERAGE_DEFINE(pinctrl_drop_buffered_packets_map);
 
 void
 pinctrl_init(void)
@@ -117,6 +122,7 @@ pinctrl_init(void)
     init_put_mac_bindings();
     init_send_garps();
     init_ipv6_ras();
+    init_buffered_packets_map();
 }
 
 static ovs_be32
@@ -190,9 +196,180 @@ set_actions_and_enqueue_msg(const struct dp_packet *packet,
     ofpbuf_uninit(&ofpacts);
 }
 
+struct buffer_info {
+    struct ofpbuf ofpacts;
+    struct dp_packet *p;
+};
+
+#define BUFFER_QUEUE_DEPTH     4
+struct buffered_packets {
+    struct hmap_node hmap_node;
+
+    /* key */
+    struct in6_addr ip;
+
+    long long int timestamp;
+
+    struct buffer_info data[BUFFER_QUEUE_DEPTH];
+    uint32_t head, tail;
+};
+
+static struct hmap buffered_packets_map;
+
+static void
+init_buffered_packets_map(void)
+{
+    hmap_init(&buffered_packets_map);
+}
+
+static void
+destroy_buffered_packets(struct buffered_packets *bp)
+{
+    struct buffer_info *bi;
+
+    while (bp->head != bp->tail) {
+        bi = &bp->data[bp->head];
+        dp_packet_uninit(bi->p);
+        ofpbuf_uninit(&bi->ofpacts);
+
+        bp->head = (bp->head + 1) % BUFFER_QUEUE_DEPTH;
+    }
+    hmap_remove(&buffered_packets_map, &bp->hmap_node);
+    free(bp);
+}
+
+static void
+destroy_buffered_packets_map(void)
+{
+    struct buffered_packets *bp;
+    HMAP_FOR_EACH_POP (bp, hmap_node, &buffered_packets_map) {
+        destroy_buffered_packets(bp);
+    }
+    hmap_destroy(&buffered_packets_map);
+}
+
+static void
+buffered_push_packet(struct buffered_packets *bp,
+                     struct dp_packet *packet,
+                     const struct match *md)
+{
+    uint32_t next = (bp->tail + 1) % BUFFER_QUEUE_DEPTH;
+    struct buffer_info *bi = &bp->data[bp->tail];
+
+    ofpbuf_init(&bi->ofpacts, 4096);
+
+    reload_metadata(&bi->ofpacts, md);
+    struct ofpact_resubmit *resubmit = ofpact_put_RESUBMIT(&bi->ofpacts);
+    resubmit->in_port = OFPP_CONTROLLER;
+    resubmit->table_id = OFTABLE_REMOTE_OUTPUT;
+
+    bi->p = packet;
+
+    if (next == bp->head) {
+        bi = &bp->data[bp->head];
+        dp_packet_uninit(bi->p);
+        ofpbuf_uninit(&bi->ofpacts);
+        bp->head = (bp->head + 1) % BUFFER_QUEUE_DEPTH;
+    }
+    bp->tail = next;
+}
+
+static void
+buffered_send_packets(struct buffered_packets *bp, struct eth_addr *addr)
+{
+    enum ofp_version version = rconn_get_version(swconn);
+    enum ofputil_protocol proto = ofputil_protocol_from_ofp_version(version);
+
+    while (bp->head != bp->tail) {
+        struct buffer_info *bi = &bp->data[bp->head];
+        struct eth_header *eth = dp_packet_data(bi->p);
+
+        eth->eth_dst = *addr;
+        struct ofputil_packet_out po = {
+            .packet = dp_packet_data(bi->p),
+            .packet_len = dp_packet_size(bi->p),
+            .buffer_id = UINT32_MAX,
+            .ofpacts = bi->ofpacts.data,
+            .ofpacts_len = bi->ofpacts.size,
+        };
+        match_set_in_port(&po.flow_metadata, OFPP_CONTROLLER);
+        queue_msg(ofputil_encode_packet_out(&po, proto));
+
+        ofpbuf_uninit(&bi->ofpacts);
+        dp_packet_uninit(bi->p);
+
+        bp->head = (bp->head + 1) % BUFFER_QUEUE_DEPTH;
+    }
+}
+
+#define BUFFER_MAP_TIMEOUT   10000
 static void
-pinctrl_handle_arp(const struct flow *ip_flow, const struct match *md,
-                   struct ofpbuf *userdata)
+buffered_packets_map_gc(void)
+{
+    struct buffered_packets *cur_qp, *next_qp;
+    long long int now = time_msec();
+
+    HMAP_FOR_EACH_SAFE (cur_qp, next_qp, hmap_node, &buffered_packets_map) {
+        if (now > cur_qp->timestamp + BUFFER_MAP_TIMEOUT) {
+            destroy_buffered_packets(cur_qp);
+        }
+    }
+}
+
+static struct buffered_packets *
+pinctrl_find_buffered_packets(const struct in6_addr *ip, uint32_t hash)
+{
+    struct buffered_packets *qp;
+
+    HMAP_FOR_EACH_WITH_HASH (qp, hmap_node, hash,
+                             &buffered_packets_map) {
+        if (IN6_ARE_ADDR_EQUAL(&qp->ip, ip)) {
+            return qp;
+        }
+    }
+    return NULL;
+}
+
+static int
+pinctrl_handle_buffered_packets(const struct flow *ip_flow,
+                                struct dp_packet *pkt_in,
+                                const struct match *md, bool is_arp)
+{
+    struct buffered_packets *bp;
+    struct dp_packet *clone;
+    struct in6_addr addr;
+
+    if (is_arp) {
+        addr = in6_addr_mapped_ipv4(ip_flow->nw_dst);
+    } else {
+        addr = ip_flow->ipv6_dst;
+    }
+
+    uint32_t hash = hash_bytes(&addr, sizeof addr, 0);
+    bp = pinctrl_find_buffered_packets(&addr, hash);
+    if (!bp) {
+        if (hmap_count(&buffered_packets_map) >= 1000) {
+            COVERAGE_INC(pinctrl_drop_buffered_packets_map);
+            return -ENOMEM;
+        }
+
+        bp = xmalloc(sizeof *bp);
+        hmap_insert(&buffered_packets_map, &bp->hmap_node, hash);
+        bp->head = bp->tail = 0;
+        bp->ip = addr;
+    }
+    bp->timestamp = time_msec();
+    /* clone the packet to send it later with correct L2 address */
+    clone = dp_packet_clone_data(dp_packet_data(pkt_in),
+                                 dp_packet_size(pkt_in));
+    buffered_push_packet(bp, clone, md);
+
+    return 0;
+}
+
+static void
+pinctrl_handle_arp(const struct flow *ip_flow, struct dp_packet *pkt_in,
+                   const struct match *md, struct ofpbuf *userdata)
 {
     /* This action only works for IP packets, and the switch should only send
      * us IP packets this way, but check here just to be sure. */
@@ -203,6 +380,8 @@ pinctrl_handle_arp(const struct flow *ip_flow, const struct match *md,
         return;
     }
 
+    pinctrl_handle_buffered_packets(ip_flow, pkt_in, md, true);
+
     /* Compose an ARP packet. */
     uint64_t packet_stub[128 / 8];
     struct dp_packet packet;
@@ -1162,7 +1341,7 @@ process_packet_in(const struct ofp_header *msg,
 
     switch (ntohl(ah->opcode)) {
     case ACTION_OPCODE_ARP:
-        pinctrl_handle_arp(&headers, &pin.flow_metadata, &userdata);
+        pinctrl_handle_arp(&headers, &packet, &pin.flow_metadata, &userdata);
         break;
 
     case ACTION_OPCODE_PUT_ARP:
@@ -1207,7 +1386,8 @@ process_packet_in(const struct ofp_header *msg,
         break;
 
     case ACTION_OPCODE_ND_NS:
-        pinctrl_handle_nd_ns(&headers, &pin.flow_metadata, &userdata);
+        pinctrl_handle_nd_ns(&headers, &packet, &pin.flow_metadata,
+                             &userdata);
         break;
 
     case ACTION_OPCODE_ICMP:
@@ -1310,6 +1490,7 @@ pinctrl_run(struct ovsdb_idl_txn *ovnsb_idl_txn,
                   local_datapaths, active_tunnels);
     send_ipv6_ras(sbrec_port_binding_by_datapath,
                   sbrec_port_binding_by_name, local_datapaths);
+    buffered_packets_map_gc();
 }
 
 /* Table of ipv6_ra_state structures, keyed on logical port name */
@@ -1620,6 +1801,7 @@ pinctrl_destroy(void)
     destroy_put_mac_bindings();
     destroy_send_garps();
     destroy_ipv6_ras();
+    destroy_buffered_packets_map();
 }
 
 /* Implementation of the "put_arp" and "put_nd" OVN actions.  These
@@ -1642,7 +1824,7 @@ struct put_mac_binding {
     /* Key. */
     uint32_t dp_key;
     uint32_t port_key;
-    char ip_s[INET6_ADDRSTRLEN + 1];
+    struct in6_addr ip_key;
 
     /* Value. */
     struct eth_addr mac;
@@ -1666,13 +1848,13 @@ destroy_put_mac_bindings(void)
 
 static struct put_mac_binding *
 pinctrl_find_put_mac_binding(uint32_t dp_key, uint32_t port_key,
-                             const char *ip_s, uint32_t hash)
+                             const struct in6_addr *ip_key, uint32_t hash)
 {
     struct put_mac_binding *pa;
     HMAP_FOR_EACH_WITH_HASH (pa, hmap_node, hash, &put_mac_bindings) {
         if (pa->dp_key == dp_key
             && pa->port_key == port_key
-            && !strcmp(pa->ip_s, ip_s)) {
+            && IN6_ARE_ADDR_EQUAL(&pa->ip_key, ip_key)) {
             return pa;
         }
     }
@@ -1685,18 +1867,19 @@ pinctrl_handle_put_mac_binding(const struct flow *md,
 {
     uint32_t dp_key = ntohll(md->metadata);
     uint32_t port_key = md->regs[MFF_LOG_INPORT - MFF_REG0];
-    char ip_s[INET6_ADDRSTRLEN];
+    struct buffered_packets *bp;
+    struct in6_addr ip_key;
 
     if (is_arp) {
-        ovs_be32 ip = htonl(md->regs[0]);
-        inet_ntop(AF_INET, &ip, ip_s, sizeof(ip_s));
+        ip_key = in6_addr_mapped_ipv4(htonl(md->regs[0]));
     } else {
         ovs_be128 ip6 = hton128(flow_get_xxreg(md, 0));
-        inet_ntop(AF_INET6, &ip6, ip_s, sizeof(ip_s));
+        memcpy(&ip_key, &ip6, sizeof ip_key);
     }
-    uint32_t hash = hash_string(ip_s, hash_2words(dp_key, port_key));
+    uint32_t hash = hash_bytes(&ip_key, sizeof ip_key,
+                               hash_2words(dp_key, port_key));
     struct put_mac_binding *pmb
-        = pinctrl_find_put_mac_binding(dp_key, port_key, ip_s, hash);
+        = pinctrl_find_put_mac_binding(dp_key, port_key, &ip_key, hash);
     if (!pmb) {
         if (hmap_count(&put_mac_bindings) >= 1000) {
             COVERAGE_INC(pinctrl_drop_put_mac_binding);
@@ -1707,10 +1890,17 @@ pinctrl_handle_put_mac_binding(const struct flow *md,
         hmap_insert(&put_mac_bindings, &pmb->hmap_node, hash);
         pmb->dp_key = dp_key;
         pmb->port_key = port_key;
-        ovs_strlcpy_arrays(pmb->ip_s, ip_s);
+        pmb->ip_key = ip_key;
     }
     pmb->timestamp = time_msec();
     pmb->mac = headers->dl_src;
+
+    /* send queued pkts */
+    uint32_t bhash = hash_bytes(&ip_key, sizeof ip_key, 0);
+    bp = pinctrl_find_buffered_packets(&ip_key, bhash);
+    if (bp) {
+        buffered_send_packets(bp, &pmb->mac);
+    }
 }
 
 static const struct sbrec_mac_binding *
@@ -1760,25 +1950,23 @@ run_put_mac_binding(struct ovsdb_idl_txn *ovnsb_idl_txn,
     snprintf(mac_string, sizeof mac_string,
              ETH_ADDR_FMT, ETH_ADDR_ARGS(pmb->mac));
 
-    /* Check for and update an existing IP-MAC binding for this logical
-     * port.
-     */
+    struct ds ip_s = DS_EMPTY_INITIALIZER;
+    ipv6_format_mapped(&pmb->ip_key, &ip_s);
+
+    /* Update or add an IP-MAC binding for this logical port. */
     const struct sbrec_mac_binding *b =
         mac_binding_lookup(sbrec_mac_binding_by_lport_ip, pb->logical_port,
-                           pmb->ip_s);
-    if (b) {
-        if (strcmp(b->mac, mac_string)) {
-            sbrec_mac_binding_set_mac(b, mac_string);
-        }
-        return;
-    }
-
-    /* Add new IP-MAC binding for this logical port. */
-    b = sbrec_mac_binding_insert(ovnsb_idl_txn);
-    sbrec_mac_binding_set_logical_port(b, pb->logical_port);
-    sbrec_mac_binding_set_ip(b, pmb->ip_s);
-    sbrec_mac_binding_set_mac(b, mac_string);
-    sbrec_mac_binding_set_datapath(b, pb->datapath);
+                           ds_cstr(&ip_s));
+    if (!b) {
+        b = sbrec_mac_binding_insert(ovnsb_idl_txn);
+        sbrec_mac_binding_set_logical_port(b, pb->logical_port);
+        sbrec_mac_binding_set_ip(b, ds_cstr(&ip_s));
+        sbrec_mac_binding_set_mac(b, mac_string);
+        sbrec_mac_binding_set_datapath(b, pb->datapath);
+    } else if (strcmp(b->mac, mac_string)) {
+        sbrec_mac_binding_set_mac(b, mac_string);
+    }
+    ds_destroy(&ip_s);
 }
 
 static void
@@ -2409,8 +2597,8 @@ pinctrl_handle_nd_na(const struct flow *ip_flow, const struct match *md,
 }
 
 static void
-pinctrl_handle_nd_ns(const struct flow *ip_flow, const struct match *md,
-                     struct ofpbuf *userdata)
+pinctrl_handle_nd_ns(const struct flow *ip_flow, struct dp_packet *pkt_in,
+                     const struct match *md, struct ofpbuf *userdata)
 {
     /* This action only works for IPv6 packets. */
     if (get_dl_type(ip_flow) != htons(ETH_TYPE_IPV6)) {
@@ -2419,6 +2607,8 @@ pinctrl_handle_nd_ns(const struct flow *ip_flow, const struct match *md,
         return;
     }
 
+    pinctrl_handle_buffered_packets(ip_flow, pkt_in, md, false);
+
     uint64_t packet_stub[128 / 8];
     struct dp_packet packet;
     dp_packet_use_stub(&packet, packet_stub, sizeof packet_stub);