dpdk-ring - read timestamp from hw metadata if available

Author: TheSableCZ

input/dpdk-ring.cpp

@@ -141,11 +141,30 @@ void DpdkRingReader::init(const char* params)
     } else {
         is_reader_ready = true;
     }
+    getDynfieldInfo();
 }
 
 struct timeval DpdkRingReader::getTimestamp(rte_mbuf* mbuf)
 {
     struct timeval tv;
+    if (m_nfbMetadataEnabled) {
+        uint64_t nfb_dynflag_mask = (1ULL << m_nfbMetadataDynfieldInfo.dynflag_bit_index);
+
+        if (mbuf->ol_flags & nfb_dynflag_mask) {
+            const uint16_t ct_hdr_offset = *RTE_MBUF_DYNFIELD(
+                mbuf, m_nfbMetadataDynfieldInfo.dynfield_byte_index, uint16_t*
+            );
+
+            struct NfbMetadata *ct_hdr = (struct NfbMetadata*)
+                ((uint8_t*)mbuf->buf_addr + ct_hdr_offset);
+
+            tv.tv_sec = ct_hdr->timestamp.timestamp_s;
+            tv.tv_usec = ct_hdr->timestamp.timestamp_ns / 1000;
+            return tv;
+        }
+    }
+    
+    // fallback to software timestamp
     auto now = std::chrono::system_clock::now();
     auto now_t = std::chrono::system_clock::to_time_t(now);
 
@@ -210,4 +229,31 @@ void DpdkRingReader::configure_telemetry_dirs(
     register_file(queues_dir, "input-stats", statsOps);
 }
 
+void DpdkRingReader::getDynfieldInfo()
+{
+    struct rte_mbuf_dynfield dynfield_params;
+    struct rte_mbuf_dynflag dynflag_param;
+    int ret;
+    bool dynflag_found = false;
+    bool dynfield_found = false;
+
+    rte_errno = 0;
+    ret = rte_mbuf_dynflag_lookup("rte_net_nfb_dynflag_header_vld", &dynflag_param);
+    if (ret >= 0) {
+        m_nfbMetadataDynfieldInfo.dynflag_bit_index = ret;
+        dynflag_found = true;
+    }
+
+    rte_errno = 0;
+    ret = rte_mbuf_dynfield_lookup("rte_net_nfb_dynfield_header_offset", &dynfield_params);
+    if (ret >= 0) {
+        m_nfbMetadataDynfieldInfo.dynfield_byte_index = ret;
+        dynfield_found = true;
+    }
+
+    if (dynflag_found && dynfield_found) {
+        m_nfbMetadataEnabled = true;
+    }
+}
+
 } // namespace ipxp

input/dpdk-ring.h

@@ -134,7 +134,24 @@ class DpdkRingReader : public InputPlugin {
         uint64_t receivedBytes;
     };
 
+    struct NfbMetadataDynfieldInfo {
+        int dynflag_bit_index;
+        int dynfield_byte_index;
+    };
+
+    struct NfbTimestamp {
+        uint32_t timestamp_ns;
+        uint32_t timestamp_s;
+    } __rte_packed;
+
+    struct NfbMetadata {
+        NfbTimestamp timestamp;
+        uint16_t matched;
+        uint32_t hash;
+    } __rte_packed;
+
     telemetry::Content get_queue_telemetry();
+    void getDynfieldInfo();
 
     std::vector<rte_mbuf *> mbufs_;
     std::uint16_t pkts_read_;
@@ -145,6 +162,8 @@ class DpdkRingReader : public InputPlugin {
     rte_ring *m_ring;
     bool is_reader_ready = false;
     DpdkRingStats m_stats = {};
+    bool m_nfbMetadataEnabled = false;
+    NfbMetadataDynfieldInfo m_nfbMetadataDynfieldInfo = {};
 };
 } // namespace ipxp