Fix Toeplitz hash computation when using the default RSS key

include/tulips/stack/Utils.h

@@ -26,6 +26,6 @@ cap(const uint32_t length)
 uint32_t toeplitz(stack::ipv4::Address const& saddr,
                   stack::ipv4::Address const& daddr, const uint16_t sport,
                   const uint16_t dport, const size_t key_len,
-                  const uint8_t* const key);
+                  const uint8_t* const key, const uint32_t init);
 
 }

include/tulips/transport/ena/RedirectionTable.h

@@ -24,9 +24,9 @@ class RedirectionTable
 
   static Ref allocate(const uint16_t portid, const size_t nqus,
                       const size_t size, const size_t hlen,
-                      const uint8_t* const hkey)
+                      const uint8_t* const hkey, const bool dflt)
   {
-    return Ref(new RedirectionTable(portid, nqus, size, hlen, hkey));
+    return Ref(new RedirectionTable(portid, nqus, size, hlen, hkey, dflt));
   }
 
   /*
@@ -49,7 +49,8 @@ class RedirectionTable
    */
 
   RedirectionTable(const uint16_t portid, const size_t nqus, const size_t size,
-                   const size_t hlen, const uint8_t* const hkey);
+                   const size_t hlen, const uint8_t* const hkey,
+                   const bool dflt);
 
   /*
    * Attributes.
@@ -59,6 +60,7 @@ class RedirectionTable
   size_t m_size;
   size_t m_hlen;
   const uint8_t* m_hkey;
+  bool m_default;
   struct rte_eth_rss_reta_entry64* m_table;
 };
 

src/stack/Utils.cpp

@@ -86,9 +86,9 @@ headerLength(const uint8_t* const packet, const uint32_t plen, uint32_t& len)
 uint32_t
 toeplitz(stack::ipv4::Address const& saddr, stack::ipv4::Address const& daddr,
          const uint16_t sport, const uint16_t dport, const size_t len,
-         const uint8_t* const key)
+         const uint8_t* const key, const uint32_t init)
 {
-  uint32_t ret = 0;
+  uint32_t ret = init;
   uint8_t tuple[12];
   /*
    * Copy the key in a local buffer.

src/transport/ena/Port.cpp

@@ -366,11 +366,12 @@ void
 Port::setupReceiveSideScaling(struct rte_eth_dev_info const& dev_info,
                               const uint16_t nqus)
 {
+  auto hlen = dev_info.hash_key_size;
+  auto hkey = new uint8_t[hlen];
+  auto dflt = false;
   /*
    * Get the RSS configuration.
    */
-  auto hlen = dev_info.hash_key_size;
-  auto hkey = new uint8_t[hlen];
   struct rte_eth_rss_conf rss_conf = { .rss_key = hkey };
   auto ret = rte_eth_dev_rss_hash_conf_get(m_portid, &rss_conf);
   if (ret != 0) {
@@ -384,20 +385,17 @@ Port::setupReceiveSideScaling(struct rte_eth_dev_info const& dev_info,
      */
     hlen = ENA_LEGACY_HASH_KEY_LEN;
     hkey = new uint8_t[hlen];
+    dflt = true;
     /*
-     * Copy the legacy key by flipping it:
-     *
-     * https://github.com/amzn/amzn-drivers/issues/267#issuecomment-1566119986
+     * Copy the legacy key.
      */
-    for (size_t i = 0; i < ENA_LEGACY_HASH_KEY_LEN; i += 1) {
-      hkey[i] = ENA_LEGACY_HASH_KEY[ENA_LEGACY_HASH_KEY_LEN - i];
-    }
+    memcpy(hkey, ENA_LEGACY_HASH_KEY, hlen);
   }
   /*
    * Allocate the redirection table.
    */
   auto size = dev_info.reta_size;
-  m_reta = RedirectionTable::allocate(m_portid, nqus, size, hlen, hkey);
+  m_reta = RedirectionTable::allocate(m_portid, nqus, size, hlen, hkey, dflt);
 }
 
 }

src/transport/ena/RawProcessor.cpp

@@ -1,7 +1,6 @@
 #include <tulips/stack/Ethernet.h>
 #include <tulips/system/SpinLock.h>
 #include <tulips/transport/ena/RawProcessor.h>
-#include <iostream>
 #include <mutex>
 #include <netinet/in.h>
 

src/transport/ena/RedirectionTable.cpp

@@ -1,17 +1,21 @@
 #include <tulips/stack/Utils.h>
 #include <tulips/system/SpinLock.h>
 #include <tulips/transport/ena/RedirectionTable.h>
+#include <cstdint>
+#include <iostream>
 #include <mutex>
+#include <endian.h>
 
 namespace tulips::transport::ena {
 
 RedirectionTable::RedirectionTable(const uint16_t portid, const size_t nqus,
                                    const size_t size, const size_t hlen,
-                                   const uint8_t* const hkey)
+                                   const uint8_t* const hkey, const bool dflt)
   : m_portid(portid)
   , m_size(size)
   , m_hlen(hlen)
   , m_hkey(hkey)
+  , m_default(dflt)
   , m_table(new struct rte_eth_rss_reta_entry64[size >> 6])
 {
   auto count = size >> 6;
@@ -46,6 +50,10 @@ RedirectionTable::RedirectionTable(const uint16_t portid, const size_t nqus,
    * Reserve the first slot to redirect L2 flows to queue 0.
    */
   m_table[0].reta[0] = 0;
+  stack::utils::hexdump((const uint8_t*)m_table[0].reta,
+                        sizeof(m_table[0].reta), std::cout);
+  stack::utils::hexdump((const uint8_t*)m_table[0].reta,
+                        sizeof(m_table[0].reta), std::cout);
   /*
    * Update the RETA.
    */
@@ -69,10 +77,36 @@ RedirectionTable::match(stack::ipv4::Address const& laddr, const uint16_t lport,
                         const uint16_t queueid)
 {
   using stack::utils::toeplitz;
+  stack::ipv4::Address rx_ip = laddr, tx_ip = raddr;
+  uint16_t rx_port = lport, tx_port = rport;
+  uint32_t init = 0;
+  /*
+   * Re-order IPs and ports if necessary: https://tinyurl.com/mryamc52
+   */
+  if (m_default) {
+    if (be32toh(*rx_ip.data()) < be32toh(*tx_ip.data())) {
+      rx_ip = raddr;
+      tx_ip = laddr;
+    }
+    if (rx_port < tx_port) {
+      rx_port = rport;
+      tx_port = lport;
+    }
+    init = uint32_t(-1);
+  }
   /*
    * Hash the payload and get the table index.
    */
-  auto hash = toeplitz(raddr, laddr, rport, lport, m_hlen, m_hkey);
+  auto hash = toeplitz(tx_ip, rx_ip, tx_port, rx_port, m_hlen, m_hkey, init);
+  /*
+   * Default keys only use the lower 16 bits: https://tinyurl.com/47vkdanv
+   */
+  if (m_default) {
+    hash = ((hash & 0xFFFF) | (hash << 16)) & 0xFFFFFFFF;
+  }
+  /*
+   * Compute the indexes and the slot.
+   */
   uint64_t indx = hash % m_size;
   uint64_t slot = indx >> 6;
   uint64_t eidx = indx & 0x3F;
@@ -83,6 +117,9 @@ RedirectionTable::match(stack::ipv4::Address const& laddr, const uint16_t lport,
   if (preq != queueid) {
     return Status::ResourceBusy;
   }
+  std::cout << raddr.toString() << ":" << rport << " -> " << laddr.toString()
+            << ":" << lport << " = " << std::hex << hash << std::dec
+            << std::endl;
   /*
    * Done.
    */

tests/stack/utils.cpp

@@ -6,15 +6,23 @@ using namespace tulips;
 
 static constexpr size_t KEY_LEN = 40;
 
-static uint8_t KEY[KEY_LEN] = {
+static uint8_t DYNAMIC_KEY[KEY_LEN] = {
   0x00, 0x8b, 0xe0, 0x5e, 0xd4, 0xa5, 0x54, 0xf8, 0x3c, 0xf8,
   0x08, 0x75, 0x07, 0x2c, 0x4e, 0x8b, 0x6f, 0x1d, 0xbf, 0x10,
   0x3b, 0x04, 0x3b, 0x41, 0xb3, 0xa4, 0xa4, 0xae, 0x56, 0xc9,
   0xa4, 0xec, 0x13, 0x76, 0xa0, 0xaf, 0x04, 0x10, 0x81, 0x66,
 };
 
-TEST(Stack, RssHashing)
+static const uint8_t STATIC_KEY[KEY_LEN] = {
+  0xbe, 0xac, 0x01, 0xfa, 0x6a, 0x42, 0xb7, 0x3b, 0x80, 0x30,
+  0xf2, 0x0c, 0x77, 0xcb, 0x2d, 0xa3, 0xae, 0x7b, 0x30, 0xb4,
+  0xd0, 0xca, 0x2b, 0xcb, 0x43, 0xa3, 0x8f, 0xb0, 0x41, 0x67,
+  0x25, 0x3d, 0x25, 0x5b, 0x0e, 0xc2, 0x6d, 0x5a, 0x56, 0xda,
+};
+
+TEST(Stack, RssHashingDynamic)
 {
+  using stack::utils::toeplitz;
   /*
    * Define the tuple entries.
    */
@@ -25,6 +33,23 @@ TEST(Stack, RssHashing)
   /*
    * Compute the hash.
    */
-  auto h = stack::utils::toeplitz(saddr, daddr, sport, dport, KEY_LEN, KEY);
+  auto h = toeplitz(saddr, daddr, sport, dport, KEY_LEN, DYNAMIC_KEY, 0);
   ASSERT_EQ(0xd90a078c, h);
 }
+
+TEST(Stack, RssHashingStatic)
+{
+  using stack::utils::toeplitz;
+  /*
+   * Define the tuple entries.
+   */
+  auto saddr = stack::ipv4::Address(10, 1, 0, 1);
+  auto daddr = stack::ipv4::Address(10, 1, 0, 2);
+  auto sport = uint16_t(8888);
+  auto dport = uint16_t(9999);
+  /*
+   * Compute the hash.
+   */
+  auto h = toeplitz(saddr, daddr, sport, dport, KEY_LEN, STATIC_KEY, -1);
+  ASSERT_EQ(0x108ad839, h);
+}