1 files changed, 64 insertions, 23 deletions

diff --git a/ofproto/netflow.c b/ofproto/netflow.c
index 50ab80a69..4881c5fdb 100644
--- a/ofproto/netflow.c
+++ b/ofproto/netflow.c
@@ -103,26 +103,19 @@ struct netflow {
     long long int reconfig_time;  /* When we reconfigured the timeouts. */
 };
 
-void
-netflow_expire(struct netflow *nf, struct netflow_flow *nf_flow,
-               struct ofexpired *expired)
+static void
+gen_netflow_rec(struct netflow *nf, struct netflow_flow *nf_flow,
+                struct ofexpired *expired, 
+                uint32_t packet_count, uint32_t byte_count)
 {
     struct netflow_v5_header *nf_hdr;
     struct netflow_v5_record *nf_rec;
-    struct timespec now;
-
-    nf_flow->last_expired += nf->active_timeout;
 
-    /* NetFlow only reports on IP packets and we should only report flows
-     * that actually have traffic. */
-    if (expired->flow.dl_type != htons(ETH_TYPE_IP) ||
-        expired->packet_count - nf_flow->packet_count_off == 0) {
-        return;
-    }
+    if (!nf->packet.size) {
+        struct timespec now;
 
-    time_wall_timespec(&now);
+        time_wall_timespec(&now);
 
-    if (!nf->packet.size) {
         nf_hdr = ofpbuf_put_zeros(&nf->packet, sizeof *nf_hdr);
         nf_hdr->version = htons(NETFLOW_V5_VERSION);
         nf_hdr->count = htons(0);
@@ -150,10 +143,8 @@ netflow_expire(struct netflow *nf, struct netflow_flow *nf_flow,
         nf_rec->input = htons(expired->flow.in_port);
         nf_rec->output = htons(nf_flow->output_iface);
     }
-    nf_rec->packet_count = htonl(MIN(expired->packet_count -
-                                     nf_flow->packet_count_off, UINT32_MAX));
-    nf_rec->byte_count = htonl(MIN(expired->byte_count -
-                                   nf_flow->byte_count_off, UINT32_MAX));
+    nf_rec->packet_count = htonl(packet_count);
+    nf_rec->byte_count = htonl(byte_count);
     nf_rec->init_time = htonl(nf_flow->created - nf->boot_time);
     nf_rec->used_time = htonl(MAX(nf_flow->created, expired->used)
                              - nf->boot_time);
@@ -172,16 +163,66 @@ netflow_expire(struct netflow *nf, struct netflow_flow *nf_flow,
     nf_rec->ip_proto = expired->flow.nw_proto;
     nf_rec->ip_tos = expired->flow.nw_tos;
 
+    /* NetFlow messages are limited to 30 records. */
+    if (ntohs(nf_hdr->count) >= 30) {
+        netflow_run(nf);
+    }
+}
+
+void
+netflow_expire(struct netflow *nf, struct netflow_flow *nf_flow,
+               struct ofexpired *expired)
+{
+    uint64_t pkt_delta = expired->packet_count - nf_flow->packet_count_off;
+    uint64_t byte_delta = expired->byte_count - nf_flow->byte_count_off;
+
+    nf_flow->last_expired += nf->active_timeout;
+
+    /* NetFlow only reports on IP packets and we should only report flows
+     * that actually have traffic. */
+    if (expired->flow.dl_type != htons(ETH_TYPE_IP) || pkt_delta == 0) {
+        return;
+    }
+
+    if ((byte_delta >> 32) <= 175) {
+        /* NetFlow v5 records are limited to 32-bit counters.  If we've wrapped
+         * a counter, send as multiple records so we don't lose track of any
+         * traffic.  We try to evenly distribute the packet and byte counters,
+         * so that the bytes-per-packet lengths don't look wonky across the
+         * records. */
+        while (byte_delta > UINT32_MAX) {
+            uint32_t n_recs = byte_delta >> 32;
+            uint32_t pkt_count = pkt_delta / n_recs;
+            uint32_t byte_count = byte_delta / n_recs;
+
+            gen_netflow_rec(nf, nf_flow, expired, pkt_count, byte_count);
+
+            pkt_delta -= pkt_count;
+            byte_delta -= byte_count;
+        }
+        if (byte_delta > 0) {
+            gen_netflow_rec(nf, nf_flow, expired, pkt_delta, byte_delta);
+        }
+    } else {
+        /* In 600 seconds, a 10GbE link can theoretically transmit 75 * 10**10
+         * == 175 * 2**32 bytes.  The byte counter is bigger than that, so it's
+         * probably a bug--for example, the netdev code uses UINT64_MAX to
+         * report "unknown value", and perhaps that has leaked through to here.
+         *
+         * We wouldn't want to hit the loop above in this case, because it
+         * would try to send up to UINT32_MAX netflow records, which would take
+         * a long time.
+         */
+        static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 1);
+
+        VLOG_WARN_RL(&rl, "impossible byte counter %"PRIu64, byte_delta);
+    }
+
     /* Update flow tracking data. */
     nf_flow->created = 0;
     nf_flow->packet_count_off = expired->packet_count;
     nf_flow->byte_count_off = expired->byte_count;
     nf_flow->tcp_flags = 0;
-
-    /* NetFlow messages are limited to 30 records. */
-    if (ntohs(nf_hdr->count) >= 30) {
-        netflow_run(nf);
-    }
 }
 
 void