fix(fib): fix lmp on hicn-light fib

Ref: HICN-834

Signed-off-by: Michele Papalini <micpapal@cisco.com>
Change-Id: Ia5648c8784f2c90fb23d1860f8ee20e21158e5e7
(cherry picked from commit 6f0a3087e4ddab4c9f039c154bb21373c1a5d96f)

2 files changed, 204 insertions, 47 deletions

diff --git a/hicn-light/src/hicn/core/fib.c b/hicn-light/src/hicn/core/fib.c
index 70c5599fb..5f8788155 100644
--- a/hicn-light/src/hicn/core/fib.c
+++ b/hicn-light/src/hicn/core/fib.c
@@ -92,6 +92,7 @@ typedef struct {
   /* Result node ancestors (NULL if not applicable) */
   fib_node_t *parent;
   fib_node_t *gparent;
+  fib_node_t *lpm;
   /* Information related to the result node */
   hicn_prefix_t *prefix;
   uint32_t prefix_len;
@@ -134,6 +135,7 @@ fib_node_t *fib_search(const fib_t *fib, const hicn_prefix_t *prefix,
 
   fib_node_t *parent = NULL;
   fib_node_t *gparent = NULL;
+  fib_node_t *lpm = NULL;
   fib_node_t *curr = fib->root;
   while (curr) {
     const hicn_prefix_t *curr_prefix = fib_entry_get_prefix(curr->entry);
@@ -141,6 +143,9 @@ fib_node_t *fib_search(const fib_t *fib, const hicn_prefix_t *prefix,
     curr_len = hicn_prefix_get_len(curr_prefix);
     match_len = hicn_prefix_lpm(prefix, curr_prefix);
 
+    // store the lpm
+    if (match_len == curr_len && curr->is_used) lpm = curr;
+
     // curr_len >= prefix_len l >= L
     // L is a prefix of l
     // > means we did not find
@@ -158,6 +163,7 @@ fib_node_t *fib_search(const fib_t *fib, const hicn_prefix_t *prefix,
   if (search) {
     search->parent = parent;
     search->gparent = gparent;
+    search->lpm = lpm;
     if (curr) {
       search->prefix_len = curr_len;
       search->match_len = match_len;
@@ -367,10 +373,10 @@ END:
  * Implementation details:
  *
  * To find whether the fib contains a prefix, we issue a search, and based on
- * the stopping conditions, we return the entry if and only if curr
+ * the stopping conditions, we return the fib note if and only if curr
  * is not NULL, and prefix_len == curr_len (== match_len)
  */
-fib_entry_t *fib_contains(const fib_t *fib, const hicn_prefix_t *prefix) {
+fib_node_t *fib_contains_node(const fib_t *fib, const hicn_prefix_t *prefix) {
   assert(fib);
   assert(prefix);
 
@@ -383,7 +389,13 @@ fib_entry_t *fib_contains(const fib_t *fib, const hicn_prefix_t *prefix) {
   if (search.match_len != prefix_len) return NULL;
   if (prefix_len != search.prefix_len) return NULL;
 
-  return curr->is_used ? curr->entry : NULL;
+  return curr->is_used ? curr : NULL;
+}
+
+fib_entry_t *fib_contains(const fib_t *fib, const hicn_prefix_t *prefix) {
+  fib_node_t *node = fib_contains_node(fib, prefix);
+  if (!node) return NULL;
+  return node->entry;
 }
 
 /*
@@ -500,12 +512,16 @@ void fib_remove(fib_t *fib, const hicn_prefix_t *prefix, unsigned conn_id) {
   assert(fib);
   assert(prefix);
 
-  fib_entry_t *entry = fib_contains(fib, prefix);
-  if (!entry) return;
+  fib_node_t *node = fib_contains_node(fib, prefix);
+  if (!node) return;
 
-  fib_entry_nexthops_remove(entry, conn_id);
-#ifndef WITH_MAPME
-  if (fib_entry_nexthops_len(entry) == 0) fib_node_remove(fib, name);
+  fib_entry_nexthops_remove(node->entry, conn_id);
+  if (fib_entry_nexthops_len(node->entry) == 0)
+  /* When using MAP-Me, we keep empty FIB entries but we mark them as unused*/
+#ifdef WITH_MAPME
+    node->is_used = false;
+#else
+    fib_node_remove(fib, name);
 #endif /* WITH_MAPME */
 }
 
@@ -515,9 +531,12 @@ static size_t fib_node_remove_connection_id(fib_node_t *node, unsigned conn_id,
   if (node->is_used) {
     fib_entry_nexthops_remove(node->entry, conn_id);
 
-    /* When using MAP-Me, we keep empty FIB entries */
-#ifndef WITH_MAPME
-    if (fib_entry_nexthops_len(node->entry) == 0) array[pos++] = node->entry;
+    /* When using MAP-Me, we keep empty FIB entries but we mark them as unused*/
+    if (fib_entry_nexthops_len(node->entry) == 0)
+#ifdef WITH_MAPME
+      node->is_used = false;
+#else
+      array[pos++] = node->entry;
 #endif /* WITH_MAPME */
   }
   pos = fib_node_remove_connection_id(node->child[ONE], conn_id, array, pos);
@@ -564,30 +583,17 @@ fib_entry_t *fib_match_msgbuf(const fib_t *fib, const msgbuf_t *msgbuf) {
 }
 
 /*
- * Implementation details:
- *
  * fib_search returns the longest non-strict subprefix.
- * - curr == NULL means no such prefix exist and we can return the parent.
- * - if we have an exact match (curr_len == key_prefix_len), then we
- *   return curr unless is_used is false, in which case we return the parent.
- * - otherwise, the parent is the longest prefix match
+ * the LPM is stored in search if it exists
  */
 fib_entry_t *fib_match_prefix(const fib_t *fib, const hicn_prefix_t *prefix) {
   assert(fib);
   assert(prefix);
 
   fib_search_t search;
-  fib_node_t *curr = fib_search(fib, prefix, &search);
-
-  if (!curr) {
-    /* This can happen with an empty FIB for instance */
-    if (!search.parent) return NULL;
-    return search.parent->entry;
-  }
-  if ((search.prefix_len == search.match_len) && curr->is_used)
-    return curr->entry;
-  if (search.parent) return search.parent->entry;
-  return NULL;
+  fib_search(fib, prefix, &search);
+  if (!search.lpm) return NULL;
+  return search.lpm->entry;
 }
 
 fib_entry_t *fib_match_name(const fib_t *fib, const hicn_name_t *name) {
@@ -632,7 +638,6 @@ bool _fib_is_valid(const fib_node_t *node) {
 
     uint32_t match_len = hicn_prefix_lpm(prefix, child_prefix);
     if (match_len != prefix_len) return false;
-    if (!node->is_used && !child->is_used) return false;
     if (hicn_prefix_get_bit(child_prefix, match_len) != i) return false;
     if (!_fib_is_valid(child)) return false;
   }
diff --git a/hicn-light/src/hicn/test/test-fib.cc b/hicn-light/src/hicn/test/test-fib.cc
index 6e1f59077..5068b4fa2 100644
--- a/hicn-light/src/hicn/test/test-fib.cc
+++ b/hicn-light/src/hicn/test/test-fib.cc
@@ -22,6 +22,7 @@
 #include <sys/un.h>
 #include <unistd.h>
 #include <netinet/in.h>
+#include <vector>
 
 extern "C" {
 #define WITH_TESTS
@@ -49,18 +50,24 @@ class FibTest : public ::testing::Test {
   fib_t *fib;
 };
 
-fib_entry_t *_fib_add_prefix(fib_t *fib, const hicn_prefix_t *prefix) {
+fib_entry_t *_fib_add_prefix(fib_t *fib, const hicn_prefix_t *prefix,
+                             std::vector<uint32_t> &nexthops) {
   fib_entry_t *entry =
       fib_entry_create(prefix, STRATEGY_TYPE_UNDEFINED, NULL, NULL);
+  for (size_t i = 0; i < nexthops.size(); i++)
+    fib_entry_nexthops_add(entry, nexthops[i]);
   fib_add(fib, entry);
   return entry;
 }
 
-#if 0
-static const hicn_prefix_t p0010 = (hicn_prefix_t){
-    .name = {.v6 = {.as_u64 = {0x1122334455667788, 0x9900aabbccddeeff}}},
-    .len = 4};
-#endif
+int compare_str_prefix_to_prefix(char *p1, hicn_prefix_t *p2) {
+  char prefix_s[MAXSZ_IP_PREFIX];
+  hicn_ip_prefix_t ipp;
+  hicn_prefix_get_ip_prefix(p2, &ipp);
+  hicn_ip_prefix_snprintf(prefix_s, MAXSZ_IP_PREFIX,
+                          (const hicn_ip_prefix_t *)&ipp);
+  return strcmp(prefix_s, p1);
+}
 
 #define HICN_PREFIX(P, STR)                      \
   hicn_prefix_t P;                               \
@@ -82,9 +89,10 @@ TEST_F(FibTest, FibAddOne) {
   const hicn_prefix_t *prefix_array[] = {&pfx};
   bool used_array[] = {true};
 
+  std::vector<uint32_t> empty_nexthop;
   for (unsigned i = 0; i < ARRAY_SIZE(prefix_array); i++) {
     if (!used_array[i]) continue;
-    _fib_add_prefix(fib, prefix_array[i]);
+    _fib_add_prefix(fib, prefix_array[i], empty_nexthop);
   }
 
   fib_dump(fib);
@@ -103,8 +111,9 @@ TEST_F(FibTest, FibAddTwo) {
   const hicn_prefix_t *prefix_array[] = {&b001, &inner_8000_1, &c001};
   bool used_array[] = {true, false, true};
 
-  _fib_add_prefix(fib, &b001);
-  _fib_add_prefix(fib, &c001);
+  std::vector<uint32_t> empty_nexthop;
+  _fib_add_prefix(fib, &b001, empty_nexthop);
+  _fib_add_prefix(fib, &c001, empty_nexthop);
 
   fib_dump(fib);
 
@@ -126,11 +135,12 @@ TEST_F(FibTest, FibAddFive) {
       &b002_abcd_0, &inner_b002_abcd_0, &b002_abcd_1};
   bool used_array[] = {true, false, true, true, true, false, true};
 
-  _fib_add_prefix(fib, &b002);
-  _fib_add_prefix(fib, &b002_abcd_0);
-  _fib_add_prefix(fib, &b002_2);
-  _fib_add_prefix(fib, &b002_abcd_1);
-  _fib_add_prefix(fib, &b002_3);
+  std::vector<uint32_t> empty_nexthop;
+  _fib_add_prefix(fib, &b002, empty_nexthop);
+  _fib_add_prefix(fib, &b002_abcd_0, empty_nexthop);
+  _fib_add_prefix(fib, &b002_2, empty_nexthop);
+  _fib_add_prefix(fib, &b002_abcd_1, empty_nexthop);
+  _fib_add_prefix(fib, &b002_3, empty_nexthop);
 
   fib_dump(fib);
 
@@ -149,7 +159,8 @@ TEST_F(FibTest, FibAddRemove) {
   const hicn_prefix_t *prefix_array_3[] = {&b002_64};
   bool used_array_3[] = {true};
 
-  fib_entry_t *entry = _fib_add_prefix(fib, &b002_128);
+  std::vector<uint32_t> empty_nexthop;
+  fib_entry_t *entry = _fib_add_prefix(fib, &b002_128, empty_nexthop);
   fib_dump(fib);
   EXPECT_TRUE(fib_is_valid(fib));
   EXPECT_TRUE(fib_check_preorder(fib, prefix_array_1, used_array_1));
@@ -159,7 +170,7 @@ TEST_F(FibTest, FibAddRemove) {
   EXPECT_TRUE(fib_is_valid(fib));
   EXPECT_TRUE(fib_check_preorder(fib, prefix_array_2, used_array_2));
 
-  entry = _fib_add_prefix(fib, &b002_64);
+  entry = _fib_add_prefix(fib, &b002_64, empty_nexthop);
   fib_dump(fib);
   EXPECT_TRUE(fib_is_valid(fib));
   EXPECT_TRUE(fib_check_preorder(fib, prefix_array_3, used_array_3));
@@ -174,13 +185,154 @@ TEST_F(FibTest, FibAddNested) {
   const hicn_prefix_t *prefix_array_2[] = {&b002_128, &b002_64};
   bool used_array_2[] = {true, true};
 
-  _fib_add_prefix(fib, &b002_128);
+  std::vector<uint32_t> empty_nexthop;
+  _fib_add_prefix(fib, &b002_128, empty_nexthop);
   fib_dump(fib);
   EXPECT_TRUE(fib_is_valid(fib));
   EXPECT_TRUE(fib_check_preorder(fib, prefix_array_1, used_array_1));
 
-  _fib_add_prefix(fib, &b002_64);
+  _fib_add_prefix(fib, &b002_64, empty_nexthop);
   fib_dump(fib);
   EXPECT_TRUE(fib_is_valid(fib));
   EXPECT_TRUE(fib_check_preorder(fib, prefix_array_2, used_array_2));
 }
+
+TEST_F(FibTest, IRIStest) {
+  char p_0_s[] = "b001:0:0:3039::/64";
+  char p_1_3_s[] = "b001::3039:0:1:2:0/128";
+  HICN_PREFIX(p_0, p_0_s);
+
+  HICN_PREFIX(p_1_2, "b001::3039:0:1:0:0/128");
+  HICN_PREFIX(p_1_1, "b001::3039:0:1:0:100/128");
+  HICN_PREFIX(p_1_3, p_1_3_s);
+  HICN_PREFIX(p_1_4, "b001::3039:0:1:0:102/128");
+
+  HICN_PREFIX(p_2_2, "b001::3039:0:2:0:0/128");
+  HICN_PREFIX(p_2_1, "b001::3039:0:2:0:100/128");
+  HICN_PREFIX(p_2_3, "b001::3039:0:2:2:0/128");
+  HICN_PREFIX(p_2_4, "b001::3039:0:2:0:102/128");
+
+  HICN_PREFIX(to_match1, "b001::3039:0:1:0:101/128");
+  HICN_PREFIX(to_match2, "b001:0:0:3039:ffff:ffff::/128");
+  HICN_PREFIX(to_match3, "b001:1::/128");
+  HICN_PREFIX(to_match4, "b001::3039:0:1:2:0/128");
+
+  std::vector<uint32_t> nexthop;
+  nexthop.push_back(2);  // add nexthop 2 to the fib entry
+  /*** add ***/
+  _fib_add_prefix(fib, &p_0, nexthop);
+  EXPECT_TRUE(fib_is_valid(fib));
+
+  _fib_add_prefix(fib, &p_1_1, nexthop);
+  EXPECT_TRUE(fib_is_valid(fib));
+
+  _fib_add_prefix(fib, &p_1_2, nexthop);
+  EXPECT_TRUE(fib_is_valid(fib));
+
+  _fib_add_prefix(fib, &p_1_3, nexthop);
+  EXPECT_TRUE(fib_is_valid(fib));
+
+  _fib_add_prefix(fib, &p_1_4, nexthop);
+  fib_dump(fib);
+  EXPECT_TRUE(fib_is_valid(fib));
+
+  /*** match ***/
+  fib_entry_t *entry = fib_match_prefix(fib, &to_match1);
+  // the matching prefix should be p0
+  EXPECT_TRUE(entry != NULL);
+  if (entry) {
+    int ret = compare_str_prefix_to_prefix(p_0_s, &(entry->prefix));
+    EXPECT_EQ(ret, 0);
+  }
+
+  entry = fib_match_prefix(fib, &to_match2);
+  // the matching prefix should be p0
+  EXPECT_TRUE(entry != NULL);
+  if (entry) {
+    int ret = compare_str_prefix_to_prefix(p_0_s, &(entry->prefix));
+    EXPECT_EQ(ret, 0);
+  }
+
+  entry = fib_match_prefix(fib, &to_match3);
+  // we expect no match
+  EXPECT_FALSE(entry != NULL);
+
+  entry = fib_match_prefix(fib, &to_match4);
+  // the matching prefix should be p_1_3
+  EXPECT_TRUE(entry != NULL);
+  if (entry) {
+    int ret = compare_str_prefix_to_prefix(p_1_3_s, &(entry->prefix));
+    EXPECT_EQ(ret, 0);
+  }
+
+  /*** remove ***/
+  fib_remove(fib, &p_0, nexthop[0]);
+  EXPECT_TRUE(fib_is_valid(fib));
+  fib_remove(fib, &p_1_1, nexthop[0]);
+  EXPECT_TRUE(fib_is_valid(fib));
+  fib_remove(fib, &p_1_2, nexthop[0]);
+  EXPECT_TRUE(fib_is_valid(fib));
+  fib_remove(fib, &p_1_3, nexthop[0]);
+  EXPECT_TRUE(fib_is_valid(fib));
+  fib_remove(fib, &p_1_4, nexthop[0]);
+  EXPECT_TRUE(fib_is_valid(fib));
+  fib_dump(fib);
+
+  /*** match ***/
+  entry = fib_match_prefix(fib, &to_match1);
+  // we expect no match
+  EXPECT_FALSE(entry != NULL);
+
+  entry = fib_match_prefix(fib, &to_match2);
+  // we expect no match
+  EXPECT_FALSE(entry != NULL);
+
+  entry = fib_match_prefix(fib, &to_match3);
+  // we expect no match
+  EXPECT_FALSE(entry != NULL);
+
+  entry = fib_match_prefix(fib, &to_match4);
+  // we expect no match
+  EXPECT_FALSE(entry != NULL);
+
+  // add again
+  _fib_add_prefix(fib, &p_0, nexthop);
+  EXPECT_TRUE(fib_is_valid(fib));
+  _fib_add_prefix(fib, &p_2_1, nexthop);
+  EXPECT_TRUE(fib_is_valid(fib));
+  _fib_add_prefix(fib, &p_2_2, nexthop);
+  EXPECT_TRUE(fib_is_valid(fib));
+  _fib_add_prefix(fib, &p_2_3, nexthop);
+  EXPECT_TRUE(fib_is_valid(fib));
+  _fib_add_prefix(fib, &p_2_4, nexthop);
+  EXPECT_TRUE(fib_is_valid(fib));
+  fib_dump(fib);
+
+  entry = fib_match_prefix(fib, &to_match1);
+  // the matching prefix should be p0
+  EXPECT_TRUE(entry != NULL);
+  if (entry) {
+    int ret = compare_str_prefix_to_prefix(p_0_s, &(entry->prefix));
+    EXPECT_EQ(ret, 0);
+  }
+
+  entry = fib_match_prefix(fib, &to_match2);
+  // the matching prefix should be p0
+  EXPECT_TRUE(entry != NULL);
+  if (entry) {
+    int ret = compare_str_prefix_to_prefix(p_0_s, &(entry->prefix));
+    EXPECT_EQ(ret, 0);
+  }
+
+  entry = fib_match_prefix(fib, &to_match3);
+  // we expect no match
+  EXPECT_FALSE(entry != NULL);
+
+  entry = fib_match_prefix(fib, &to_match4);
+  // the matching prefix should be p0
+  EXPECT_TRUE(entry != NULL);
+  if (entry) {
+    int ret = compare_str_prefix_to_prefix(p_0_s, &(entry->prefix));
+    EXPECT_EQ(ret, 0);
+  }
+}