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Neels Hofmeyr nhofmeyr at sysmocom.deImplement min/max bounds for nr_pool, adjust nr_pool_init() and current tests,
and create unit tests for nr_map wrapping.
Sequence numbers range from 0 to 65535, while TEIs range from 1 to 0xffffffff.
Both cause problems when the nr_pool surpasses the range: seq exit their valid
range, causing unmappings to fail, and a TEI would be mapped as zero (invalid).
Add a comment about TEI wrapping, and lose the comment about random TEIs (not
really important).
Sponsored-by: On-Waves ehi
---
openbsc/include/openbsc/gtphub.h | 11 +++++++--
openbsc/src/gprs/gtphub.c | 21 +++++++++-------
openbsc/tests/gtphub/gtphub_test.c | 49 ++++++++++++++++++++++++++++++++++++--
3 files changed, 68 insertions(+), 13 deletions(-)
diff --git a/openbsc/include/openbsc/gtphub.h b/openbsc/include/openbsc/gtphub.h
index c43a328..77e43e4 100644
--- a/openbsc/include/openbsc/gtphub.h
+++ b/openbsc/include/openbsc/gtphub.h
@@ -256,7 +256,8 @@ typedef unsigned int nr_t;
* If this becomes random, the tests need to be fixed. */
struct nr_pool {
nr_t last_nr;
- /* TODO add min, max, for safe wrapping */
+ nr_t nr_min;
+ nr_t nr_max;
};
struct nr_mapping {
@@ -275,7 +276,7 @@ struct nr_map {
};
-void nr_pool_init(struct nr_pool *pool);
+void nr_pool_init(struct nr_pool *pool, nr_t nr_min, nr_t nr_max);
/* Return the next unused number from the nr_pool. */
nr_t nr_pool_next(struct nr_pool *pool);
@@ -398,6 +399,12 @@ struct gtphub {
/* pointers to an entry of to_ggsns[x].peers */
struct gtphub_peer_port *ggsn_proxy[GTPH_PLANE_N];
+ /* The TEI numbers will simply wrap and be reused, which will work out
+ * in practice. Problems would arise if one given peer maintained the
+ * same TEI for a time long enough for the TEI nr map to wrap an entire
+ * uint32_t; if a new TEI were mapped every second, this would take
+ * more than 100 years (in which a single given TEI must not time out)
+ * to cause a problem. */
struct nr_map tei_map[GTPH_PLANE_N];
struct nr_pool tei_pool[GTPH_PLANE_N];
diff --git a/openbsc/src/gprs/gtphub.c b/openbsc/src/gprs/gtphub.c
index 7c7f693..155024b 100644
--- a/openbsc/src/gprs/gtphub.c
+++ b/openbsc/src/gprs/gtphub.c
@@ -577,18 +577,21 @@ void expiring_item_del(struct expiring_item *item)
/* nr_map, nr_pool */
-void nr_pool_init(struct nr_pool *pool)
+void nr_pool_init(struct nr_pool *pool, nr_t nr_min, nr_t nr_max)
{
- *pool = (struct nr_pool){};
+ *pool = (struct nr_pool){
+ .nr_min = nr_min,
+ .nr_max = nr_max,
+ .last_nr = nr_max
+ };
}
nr_t nr_pool_next(struct nr_pool *pool)
{
- pool->last_nr ++;
-
- OSMO_ASSERT(pool->last_nr > 0);
- /* TODO: gracefully handle running out of TEIs. */
- /* TODO: random TEIs. */
+ if (pool->last_nr >= pool->nr_max)
+ pool->last_nr = pool->nr_min;
+ else
+ pool->last_nr ++;
return pool->last_nr;
}
@@ -1806,7 +1809,7 @@ void gtphub_init(struct gtphub *hub)
int plane_idx;
for (plane_idx = 0; plane_idx < GTPH_PLANE_N; plane_idx++) {
- nr_pool_init(&hub->tei_pool[plane_idx]);
+ nr_pool_init(&hub->tei_pool[plane_idx], 1, 0xffffffff);
nr_map_init(&hub->tei_map[plane_idx],
&hub->tei_pool[plane_idx],
&hub->expire_tei_maps);
@@ -1974,7 +1977,7 @@ static struct gtphub_peer *gtphub_peer_new(struct gtphub *hub,
INIT_LLIST_HEAD(&peer->addresses);
- nr_pool_init(&peer->seq_pool);
+ nr_pool_init(&peer->seq_pool, 0, 0xffff);
nr_map_init(&peer->seq_map, &peer->seq_pool, &hub->expire_seq_maps);
/* TODO use something random to pick the initial sequence nr.
diff --git a/openbsc/tests/gtphub/gtphub_test.c b/openbsc/tests/gtphub/gtphub_test.c
index 4e22ac7..b1ebb40 100644
--- a/openbsc/tests/gtphub/gtphub_test.c
+++ b/openbsc/tests/gtphub/gtphub_test.c
@@ -157,7 +157,7 @@ static void test_nr_map_basic(void)
struct nr_map _map;
struct nr_map *map = &_map;
- nr_pool_init(pool);
+ nr_pool_init(pool, 1, 1000);
nr_map_init(map, pool, NULL);
OSMO_ASSERT(llist_empty(&map->mappings));
@@ -253,6 +253,50 @@ static int nr_map_is(struct nr_map *map, const char *str)
return 1;
}
+static int test_nr_map_wrap_with(nr_t nr_min, nr_t nr_max, nr_t repl_last,
+ nr_t orig_start, int orig_n,
+ const char *expect)
+{
+ struct nr_pool _pool;
+ struct nr_pool *pool = &_pool;
+ struct nr_map _map;
+ struct nr_map *map = &_map;
+
+ nr_pool_init(pool, nr_min, nr_max);
+ nr_map_init(map, pool, NULL);
+
+ pool->last_nr = repl_last;
+
+ void *origin = (void*)0x1234;
+
+ int i;
+ for (i = 0; i < orig_n; i++)
+ LVL2_ASSERT(nr_map_have(map, origin, orig_start + i, 0));
+
+ LVL2_ASSERT(nr_map_is(map, expect));
+
+ nr_map_clear(map);
+ return 1;
+}
+
+static void test_nr_map_wrap(void)
+{
+ OSMO_ASSERT(test_nr_map_wrap_with(
+ 0, UINT_MAX, UINT_MAX - 2,
+ 1, 5,
+ "(1->4294967294 at 0), "
+ "(2->4294967295 at 0), "
+ "(3->0 at 0), "
+ "(4->1 at 0), "
+ "(5->2 at 0), "
+ ));
+ OSMO_ASSERT(test_nr_map_wrap_with(
+ 5, 10, 8,
+ 1, 5,
+ "(1->9 at 0), (2->10 at 0), (3->5 at 0), (4->6 at 0), (5->7 at 0), "
+ ));
+}
+
static void test_expiry(void)
{
struct expiry expiry;
@@ -261,7 +305,7 @@ static void test_expiry(void)
int i;
expiry_init(&expiry, 30);
- nr_pool_init(&pool);
+ nr_pool_init(&pool, 1, 1000);
nr_map_init(&map, &pool, &expiry);
OSMO_ASSERT(nr_map_is(&map, ""));
@@ -947,6 +991,7 @@ int main(int argc, char **argv)
osmo_gtphub_ctx = talloc_named_const(NULL, 0, "osmo_gtphub");
test_nr_map_basic();
+ test_nr_map_wrap();
test_expiry();
test_echo();
test_create_pdp_ctx();
--
2.1.4