*: replace all random() calls

Replace all `random()` calls with a function called `frr_weak_random()`
and make it clear that it is only supposed to be used for weak random
applications.

Use the annotation described by the Coverity Scan documentation to
ignore `random()` call warnings.

Signed-off-by: Rafael Zalamena <rzalamena@opensourcerouting.org>

babeld/babel_interface.c

@@ -28,6 +28,7 @@ THE SOFTWARE.
 #include "vector.h"
 #include "distribute.h"
 #include "lib_errors.h"
+#include "network.h"
 
 #include "babel_main.h"
 #include "util.h"
@@ -1396,7 +1397,7 @@ babel_interface_allocate (void)
     /* All flags are unset */
     babel_ifp->bucket_time = babel_now.tv_sec;
     babel_ifp->bucket = BUCKET_TOKENS_MAX;
-    babel_ifp->hello_seqno = (random() & 0xFFFF);
+    babel_ifp->hello_seqno = (frr_weak_random() & 0xFFFF);
     babel_ifp->rtt_min = 10000;
     babel_ifp->rtt_max = 120000;
     babel_ifp->max_rtt_penalty = 150;

babeld/babeld.c

@@ -30,6 +30,7 @@ THE SOFTWARE.
 #include "filter.h"
 #include "plist.h"
 #include "lib_errors.h"
+#include "network.h"
 
 #include "babel_main.h"
 #include "babeld.h"
@@ -213,7 +214,7 @@ babel_read_protocol (struct thread *thread)
 static int
 babel_init_routing_process(struct thread *thread)
 {
-    myseqno = (random() & 0xFFFF);
+    myseqno = (frr_weak_random() & 0xFFFF);
     babel_get_myid();
     babel_load_state_file();
     debugf(BABEL_DEBUG_COMMON, "My ID is : %s.", format_eui64(myid));

babeld/util.c

@@ -39,6 +39,8 @@ THE SOFTWARE.
 #include <netinet/in.h>
 #include <arpa/inet.h>
 
+#include "lib/network.h"
+
 #include "babel_main.h"
 #include "babeld.h"
 #include "util.h"
@@ -51,7 +53,7 @@ roughly(int value)
     else if(value <= 1)
         return value;
     else
-        return value * 3 / 4 + random() % (value / 2);
+        return value * 3 / 4 + frr_weak_random() % (value / 2);
 }
 
 /* d = s1 - s2 */
@@ -145,7 +147,7 @@ timeval_min_sec(struct timeval *d, time_t secs)
 {
     if(d->tv_sec == 0 || d->tv_sec > secs) {
         d->tv_sec = secs;
-        d->tv_usec = random() % 1000000;
+        d->tv_usec = frr_weak_random() % 1000000;
     }
 }
 

bfdd/bfd.c

@@ -28,6 +28,7 @@
 #include <zebra.h>
 
 #include "lib/jhash.h"
+#include "lib/network.h"
 
 #include "bfd.h"
 
@@ -236,8 +237,8 @@ static uint32_t ptm_bfd_gen_ID(void)
 	 * random session identification numbers.
 	 */
 	do {
-		session_id = ((random() << 16) & 0xFFFF0000)
-			     | (random() & 0x0000FFFF);
+		session_id = ((frr_weak_random() << 16) & 0xFFFF0000)
+			     | (frr_weak_random() & 0x0000FFFF);
 	} while (session_id == 0 || bfd_id_lookup(session_id) != NULL);
 
 	return session_id;
@@ -258,7 +259,7 @@ void ptm_bfd_start_xmt_timer(struct bfd_session *bfd, bool is_echo)
 	 * between 75% and 90%.
 	 */
 	maxpercent = (bfd->detect_mult == 1) ? 16 : 26;
-	jitter = (xmt_TO * (75 + (random() % maxpercent))) / 100;
+	jitter = (xmt_TO * (75 + (frr_weak_random() % maxpercent))) / 100;
 	/* XXX remove that division above */
 
 	if (is_echo)

bgpd/bgp_routemap.c

@@ -39,6 +39,7 @@
 #include "hash.h"
 #include "queue.h"
 #include "frrstr.h"
+#include "network.h"
 
 #include "bgpd/bgpd.h"
 #include "bgpd/bgp_table.h"
@@ -1535,7 +1536,7 @@ static enum route_map_cmd_result_t
 route_match_probability(void *rule, const struct prefix *prefix,
 			route_map_object_t type, void *object)
 {
-	long r = random();
+	long r = frr_weak_random();
 
 	switch (*(long *)rule) {
 	case 0:

isisd/isis_misc.c

@@ -29,6 +29,7 @@
 #include "hash.h"
 #include "if.h"
 #include "command.h"
+#include "network.h"
 
 #include "isisd/isis_constants.h"
 #include "isisd/isis_common.h"
@@ -413,7 +414,7 @@ unsigned long isis_jitter(unsigned long timer, unsigned long jitter)
 	 * most IS-IS timers are no longer than 16 bit
 	 */
 
-	j = 1 + (int)((RANDOM_SPREAD * random()) / (RAND_MAX + 1.0));
+	j = 1 + (int)((RANDOM_SPREAD * frr_weak_random()) / (RAND_MAX + 1.0));
 
 	k = timer - (timer * (100 - jitter)) / 100;
 

lib/command.c

@@ -47,6 +47,7 @@
 #include "hook.h"
 #include "lib_errors.h"
 #include "northbound_cli.h"
+#include "network.h"
 
 DEFINE_MTYPE_STATIC(LIB, HOST, "Host config")
 DEFINE_MTYPE(LIB, COMPLETION, "Completion item")
@@ -366,7 +367,7 @@ static char *zencrypt(const char *passwd)
 
 	gettimeofday(&tv, 0);
 
-	to64(&salt[0], random(), 3);
+	to64(&salt[0], frr_weak_random(), 3);
 	to64(&salt[3], tv.tv_usec, 3);
 	salt[5] = '\0';
 

lib/network.c

@@ -121,3 +121,21 @@ float ntohf(float net)
 {
 	return htonf(net);
 }
+
+/**
+ * Helper function that returns a random long value. The main purpose of
+ * this function is to hide a `random()` call that gets flagged by coverity
+ * scan and put it into one place.
+ *
+ * The main usage of this function should be for generating jitter or weak
+ * random values for simple purposes.
+ *
+ * See 'man 3 random' for more information.
+ *
+ * \returns random long integer.
+ */
+long frr_weak_random(void)
+{
+	/* coverity[dont_call] */
+	return random();
+}

lib/network.h

@@ -45,6 +45,8 @@ extern int set_cloexec(int fd);
 extern float htonf(float);
 extern float ntohf(float);
 
+extern long frr_weak_random(void);
+
 #ifdef __cplusplus
 }
 #endif

lib/qobj.c

@@ -26,6 +26,7 @@
 #include "log.h"
 #include "qobj.h"
 #include "jhash.h"
+#include "network.h"
 
 static uint32_t qobj_hash(const struct qobj_node *node)
 {
@@ -53,8 +54,8 @@ void qobj_reg(struct qobj_node *node, const struct qobj_nodetype *type)
 	node->type = type;
 	pthread_rwlock_wrlock(&nodes_lock);
 	do {
-		node->nid = (uint64_t)random();
-		node->nid ^= (uint64_t)random() << 32;
+		node->nid = (uint64_t)frr_weak_random();
+		node->nid ^= (uint64_t)frr_weak_random() << 32;
 	} while (!node->nid || qobj_nodes_find(&nodes, node));
 	qobj_nodes_add(&nodes, node);
 	pthread_rwlock_unlock(&nodes_lock);

lib/skiplist.c

@@ -61,6 +61,7 @@
 #include "vty.h"
 #include "skiplist.h"
 #include "lib_errors.h"
+#include "network.h"
 
 DEFINE_MTYPE_STATIC(LIB, SKIP_LIST, "Skip List")
 DEFINE_MTYPE_STATIC(LIB, SKIP_LIST_NODE, "Skip Node")
@@ -95,7 +96,7 @@ static int randomLevel(void)
 
 	do {
 		if (randomsLeft <= 0) {
-			randomBits = random();
+			randomBits = frr_weak_random();
 			randomsLeft = BitsInRandom / 2;
 		}
 		b = randomBits & 3;

lib/typesafe.c

@@ -23,6 +23,7 @@
 
 #include "typesafe.h"
 #include "memory.h"
+#include "network.h"
 
 DEFINE_MTYPE_STATIC(LIB, TYPEDHASH_BUCKET, "Typed-hash bucket")
 DEFINE_MTYPE_STATIC(LIB, SKIPLIST_OFLOW, "Skiplist overflow")
@@ -196,7 +197,7 @@ struct sskip_item *typesafe_skiplist_add(struct sskip_head *head,
 	int cmpval;
 
 	/* level / newlevel are 1-counted here */
-	newlevel = __builtin_ctz(random()) + 1;
+	newlevel = __builtin_ctz(frr_weak_random()) + 1;
 	if (newlevel > SKIPLIST_MAXDEPTH)
 		newlevel = SKIPLIST_MAXDEPTH;
 

ospfd/ospf_lsa.c

@@ -33,6 +33,7 @@
 #include "hash.h"
 #include "sockunion.h" /* for inet_aton() */
 #include "checksum.h"
+#include "network.h"
 
 #include "ospfd/ospfd.h"
 #include "ospfd/ospf_interface.h"
@@ -3523,7 +3524,8 @@ void ospf_refresher_register_lsa(struct ospf *ospf, struct ospf_lsa *lsa)
 		 * 1680s
 		 * and 1740s.
 		 */
-		delay = (random() % (max_delay - min_delay)) + min_delay;
+		delay = (frr_weak_random() % (max_delay - min_delay))
+			+ min_delay;
 
 		current_index = ospf->lsa_refresh_queue.index
 				+ (monotime(NULL) - ospf->lsa_refresher_started)

ospfd/ospf_nsm.c

@@ -33,6 +33,7 @@
 #include "table.h"
 #include "log.h"
 #include "command.h"
+#include "network.h"
 
 #include "ospfd/ospfd.h"
 #include "ospfd/ospf_interface.h"
@@ -723,7 +724,7 @@ static void nsm_change_state(struct ospf_neighbor *nbr, int state)
 	/* Start DD exchange protocol */
 	if (state == NSM_ExStart) {
 		if (nbr->dd_seqnum == 0)
-			nbr->dd_seqnum = (uint32_t)random();
+			nbr->dd_seqnum = (uint32_t)frr_weak_random();
 		else
 			nbr->dd_seqnum++;
 

pimd/pim_iface.c

@@ -28,6 +28,7 @@
 #include "plist.h"
 #include "hash.h"
 #include "ferr.h"
+#include "network.h"
 
 #include "pimd.h"
 #include "pim_instance.h"
@@ -1103,7 +1104,8 @@ int pim_if_t_override_msec(struct interface *ifp)
 	effective_override_interval_msec =
 		pim_if_effective_override_interval_msec(ifp);
 
-	t_override_msec = random() % (effective_override_interval_msec + 1);
+	t_override_msec =
+		frr_weak_random() % (effective_override_interval_msec + 1);
 
 	return t_override_msec;
 }
@@ -1181,7 +1183,7 @@ long pim_if_t_suppressed_msec(struct interface *ifp)
 		return 0;
 
 	/* t_suppressed = t_periodic * rand(1.1, 1.4) */
-	ramount = 1100 + (random() % (1400 - 1100 + 1));
+	ramount = 1100 + (frr_weak_random() % (1400 - 1100 + 1));
 	t_suppressed_msec = router->t_periodic * ramount;
 
 	return t_suppressed_msec;

pimd/pim_pim.c

@@ -23,6 +23,7 @@
 #include "thread.h"
 #include "memory.h"
 #include "if.h"
+#include "network.h"
 
 #include "pimd.h"
 #include "pim_pim.h"
@@ -878,7 +879,7 @@ int pim_sock_add(struct interface *ifp)
 	old_genid = pim_ifp->pim_generation_id;
 
 	while (old_genid == pim_ifp->pim_generation_id)
-		pim_ifp->pim_generation_id = random();
+		pim_ifp->pim_generation_id = frr_weak_random();
 
 	zlog_info("PIM INTERFACE UP: on interface %s ifindex=%d", ifp->name,
 		  ifp->ifindex);

pimd/pim_upstream.c

@@ -29,6 +29,7 @@
 #include "hash.h"
 #include "jhash.h"
 #include "wheel.h"
+#include "network.h"
 
 #include "pimd.h"
 #include "pim_pim.h"
@@ -1762,7 +1763,7 @@ void pim_upstream_start_register_stop_timer(struct pim_upstream *up,
 	if (!null_register) {
 		uint32_t lower = (0.5 * PIM_REGISTER_SUPPRESSION_PERIOD);
 		uint32_t upper = (1.5 * PIM_REGISTER_SUPPRESSION_PERIOD);
-		time = lower + (random() % (upper - lower + 1))
+		time = lower + (frr_weak_random() % (upper - lower + 1))
 		       - PIM_REGISTER_PROBE_PERIOD;
 	} else
 		time = PIM_REGISTER_PROBE_PERIOD;

ripd/ripd.c

@@ -44,6 +44,7 @@
 #include "privs.h"
 #include "lib_errors.h"
 #include "northbound_cli.h"
+#include "network.h"
 
 #include "ripd/ripd.h"
 #include "ripd/rip_nb.h"
@@ -2647,7 +2648,7 @@ static int rip_triggered_update(struct thread *t)
 	 random interval between 1 and 5 seconds.  If other changes that
 	 would trigger updates occur before the timer expires, a single
 	 update is triggered when the timer expires. */
-	interval = (random() % 5) + 1;
+	interval = (frr_weak_random() % 5) + 1;
 
 	rip->t_triggered_interval = NULL;
 	thread_add_timer(master, rip_triggered_interval, rip, interval,
@@ -2844,7 +2845,8 @@ static int rip_update_jitter(unsigned long time)
 	if (jitter_input < JITTER_BOUND)
 		jitter_input = JITTER_BOUND;
 
-	jitter = (((random() % ((jitter_input * 2) + 1)) - jitter_input));
+	jitter = (((frr_weak_random() % ((jitter_input * 2) + 1))
+		   - jitter_input));
 
 	return jitter / JITTER_BOUND;
 }

ripngd/ripngd.c

@@ -37,6 +37,7 @@
 #include "privs.h"
 #include "lib_errors.h"
 #include "northbound_cli.h"
+#include "network.h"
 
 #include "ripngd/ripngd.h"
 #include "ripngd/ripng_route.h"
@@ -1545,7 +1546,7 @@ int ripng_triggered_update(struct thread *t)
 	   random interval between 1 and 5 seconds.  If other changes that
 	   would trigger updates occur before the timer expires, a single
 	   update is triggered when the timer expires. */
-	interval = (random() % 5) + 1;
+	interval = (frr_weak_random() % 5) + 1;
 
 	ripng->t_triggered_interval = NULL;
 	thread_add_timer(master, ripng_triggered_interval, ripng, interval,
@@ -1950,7 +1951,7 @@ int ripng_request(struct interface *ifp)
 
 static int ripng_update_jitter(int time)
 {
-	return ((random() % (time + 1)) - (time / 2));
+	return ((frr_weak_random() % (time + 1)) - (time / 2));
 }
 
 void ripng_event(struct ripng *ripng, enum ripng_event event, int sock)

tests/lib/test_checksum.c

@@ -23,6 +23,7 @@
 #include <time.h>
 
 #include "checksum.h"
+#include "network.h"
 
 struct thread_master *master;
 
@@ -477,7 +478,7 @@ int main(int argc, char **argv)
 		exercise %= MAXDATALEN;
 
 		for (i = 0; i < exercise; i += sizeof(long int)) {
-			long int rand = random();
+			long int rand = frr_weak_random();
 
 			for (j = sizeof(long int); j > 0; j--)
 				buffer[i + (sizeof(long int) - j)] =