The bitmap now adds an allocate_random function that randomly assigns
an identifier. This can be disabled at build time (not recommended).
---
include/ouroboros/bitmap.h | 2 ++
src/irmd/main.c | 4 ++--
src/lib/CMakeLists.txt | 2 ++
src/lib/bitmap.c | 28 ++++++++++++++++++++++++++++
src/lib/config.h.in | 1 +
src/lib/dev.c | 2 +-
6 files changed, 36 insertions(+), 3 deletions(-)
diff --git a/include/ouroboros/bitmap.h b/include/ouroboros/bitmap.h
index 02e4de4..32e027d 100644
--- a/include/ouroboros/bitmap.h
+++ b/include/ouroboros/bitmap.h
@@ -36,6 +36,8 @@ void bmp_destroy(struct bmp * bmp);
ssize_t bmp_allocate(struct bmp * bmp);
+ssize_t bmp_allocate_random(struct bmp * bmp);
+
int bmp_release(struct bmp * bmp,
ssize_t id);
diff --git a/src/irmd/main.c b/src/irmd/main.c
index d3f7a09..6432c9f 100644
--- a/src/irmd/main.c
+++ b/src/irmd/main.c
@@ -1281,7 +1281,7 @@ static int flow_alloc(pid_t pid,
}
pthread_rwlock_wrlock(&irmd.flows_lock);
- flow_id = bmp_allocate(irmd.flow_ids);
+ flow_id = bmp_allocate_random(irmd.flow_ids);
if (!bmp_is_id_valid(irmd.flow_ids, flow_id)) {
pthread_rwlock_unlock(&irmd.flows_lock);
log_err("Could not allocate flow_id.");
@@ -1515,7 +1515,7 @@ static struct irm_flow * flow_req_arr(pid_t pid,
pthread_rwlock_unlock(&irmd.reg_lock);
pthread_rwlock_wrlock(&irmd.flows_lock);
- flow_id = bmp_allocate(irmd.flow_ids);
+ flow_id = bmp_allocate_random(irmd.flow_ids);
if (!bmp_is_id_valid(irmd.flow_ids, flow_id)) {
pthread_rwlock_unlock(&irmd.flows_lock);
return NULL;
diff --git a/src/lib/CMakeLists.txt b/src/lib/CMakeLists.txt
index 42164fa..2d06cdc 100644
--- a/src/lib/CMakeLists.txt
+++ b/src/lib/CMakeLists.txt
@@ -178,6 +178,8 @@ set(SHM_RBUFF_LOCKLESS 0 CACHE BOOL
"Enable shared memory lockless rbuff support")
set(QOS_DISABLE_CRC TRUE CACHE BOOL
"Ignores ber setting on all QoS cubes")
+set(BITMAP_DISABLE_RANDOM FALSE CACHE BOOL
+ "Disable randomized allocation of identifiers")
set(SOURCE_FILES_DEV
# Add source files here
diff --git a/src/lib/bitmap.c b/src/lib/bitmap.c
index dfec08d..d0aef7e 100644
--- a/src/lib/bitmap.c
+++ b/src/lib/bitmap.c
@@ -20,7 +20,12 @@
* Foundation, Inc., http://www.fsf.org/about/contact/.
*/
+#include "config.h"
+
#include <ouroboros/bitmap.h>
+#ifndef BITMAP_DISABLE_RANDOM
+#include <ouroboros/random.h>
+#endif
#include <assert.h>
#include <stdlib.h>
@@ -153,6 +158,29 @@ ssize_t bmp_allocate(struct bmp * bmp)
return id + bmp->offset;
}
+ssize_t bmp_allocate_random(struct bmp * bmp)
+{
+ size_t id;
+
+ assert(bmp);
+
+#ifndef BITMAP_DISABLE_RANDOM
+ random_buffer(&id, sizeof(id));
+ id %= bmp->size;
+ if (bmp_is_id_used(bmp, id + bmp->offset)) {
+#endif
+ id = find_next_zero_bit(bmp->bitmap, bmp->size);
+ if (id >= bmp->size)
+ return bad_id(bmp);
+#ifndef BITMAP_DISABLE_RANDOM
+ }
+#endif
+
+ bitmap_set(bmp->bitmap, id);
+
+ return id + bmp->offset;
+}
+
static bool is_id_valid(struct bmp * bmp,
ssize_t id)
{
diff --git a/src/lib/config.h.in b/src/lib/config.h.in
index e8cfeba..9e58bec 100644
--- a/src/lib/config.h.in
+++ b/src/lib/config.h.in
@@ -29,6 +29,7 @@
#cmakedefine SHM_RBUFF_LOCKLESS
#cmakedefine SHM_RDRB_MULTI_BLOCK
#cmakedefine QOS_DISABLE_CRC
+#cmakedefine BITMAP_DISABLE_RANDOM
#define SHM_RBUFF_PREFIX "@SHM_RBUFF_PREFIX@"
#define SHM_LOCKFILE_NAME "@SHM_LOCKFILE_NAME@"
diff --git a/src/lib/dev.c b/src/lib/dev.c
index 6dbb925..1fad6b9 100644
--- a/src/lib/dev.c
+++ b/src/lib/dev.c
@@ -280,7 +280,7 @@ static int flow_init(int flow_id,
pthread_rwlock_wrlock(&ai.lock);
- fd = bmp_allocate(ai.fds);
+ fd = bmp_allocate_random(ai.fds);
if (!bmp_is_id_valid(ai.fds, fd)) {
err = -EBADF;
goto fail_fds;
--
2.19.1
