Make rate-limits go up to SIZE_MAX/EV_SSIZE_MAX, not just INT32_MAX

Someday, when networks are far faster and people frequently want a
burst value greater than 2GB per tick, this will seem very forsightful
indeed.

For now, it breaks ABI, but not source.  Fixes bug 3092096.

bufferevent-internal.h

@@ -96,7 +96,7 @@ struct bufferevent_rate_limit_group {
 
 	/** The smallest number of bytes that any member of the group should
 	 * be limited to read or write at a time. */
-	ev_int32_t min_share;
+	ev_ssize_t min_share;
 	/** Timeout event that goes off once a tick, when the bucket is ready
 	 * to refill. */
 	struct event master_refill_event;

bufferevent_ratelim.c

@@ -138,8 +138,8 @@ ev_token_bucket_get_tick(const struct timeval *tv,
 }
 
 struct ev_token_bucket_cfg *
-ev_token_bucket_cfg_new(ev_uint32_t read_rate, ev_uint32_t read_burst,
+ev_token_bucket_cfg_new(size_t read_rate, size_t read_burst,
-    ev_uint32_t write_rate, ev_uint32_t write_burst,
+    size_t write_rate, size_t write_burst,
     const struct timeval *tick_len)
 {
 	struct ev_token_bucket_cfg *r;
@@ -152,6 +152,11 @@ ev_token_bucket_cfg_new(ev_uint32_t read_rate, ev_uint32_t read_burst,
 	if (read_rate > read_burst || write_rate > write_burst ||
 	    read_rate < 1 || write_rate < 1)
 		return NULL;
+	if (read_rate > EV_RATE_LIMIT_MAX ||
+	    write_rate > EV_RATE_LIMIT_MAX ||
+	    read_burst > EV_RATE_LIMIT_MAX ||
+	    write_burst > EV_RATE_LIMIT_MAX)
+		return NULL;
 	r = mm_calloc(1, sizeof(struct ev_token_bucket_cfg));
 	if (!r)
 		return NULL;
@@ -221,7 +226,7 @@ _bufferevent_get_rlim_max(struct bufferevent_private *bev, int is_write)
 	if (bev->rate_limiting->group) {
 		struct bufferevent_rate_limit_group *g =
 		    bev->rate_limiting->group;
-		ev_int32_t share;
+		ev_ssize_t share;
 		LOCK_GROUP(g);
 		if (GROUP_SUSPENDED(g)) {
 			/* We can get here if we failed to lock this
@@ -655,9 +660,9 @@ bufferevent_rate_limit_group_set_cfg(
 		&g->rate_limit_cfg.tick_timeout, &cfg->tick_timeout, ==);
 	memcpy(&g->rate_limit_cfg, cfg, sizeof(g->rate_limit_cfg));
 
-	if (g->rate_limit.read_limit > (ev_int32_t)cfg->read_maximum)
+	if (g->rate_limit.read_limit > (ev_ssize_t)cfg->read_maximum)
 		g->rate_limit.read_limit = cfg->read_maximum;
-	if (g->rate_limit.write_limit > (ev_int32_t)cfg->write_maximum)
+	if (g->rate_limit.write_limit > (ev_ssize_t)cfg->write_maximum)
 		g->rate_limit.write_limit = cfg->write_maximum;
 
 	if (!same_tick) {
@@ -674,7 +679,7 @@ bufferevent_rate_limit_group_set_min_share(
 	struct bufferevent_rate_limit_group *g,
 	size_t share)
 {
-	if (share > EV_INT32_MAX)
+	if (share > EV_SSIZE_MAX)
 		return -1;
 
 	g->min_share = share;
@@ -865,7 +870,7 @@ int
 bufferevent_decrement_read_limit(struct bufferevent *bev, ev_ssize_t decr)
 {
 	int r = 0;
-	ev_int32_t old_limit, new_limit;
+	ev_ssize_t old_limit, new_limit;
 	struct bufferevent_private *bevp;
 	BEV_LOCK(bev);
 	bevp = BEV_UPCAST(bev);
@@ -894,7 +899,7 @@ bufferevent_decrement_write_limit(struct bufferevent *bev, ev_ssize_t decr)
 	/* XXXX this is mostly copy-and-paste from
 	 * bufferevent_decrement_read_limit */
 	int r = 0;
-	ev_int32_t old_limit, new_limit;
+	ev_ssize_t old_limit, new_limit;
 	struct bufferevent_private *bevp;
 	BEV_LOCK(bev);
 	bevp = BEV_UPCAST(bev);
@@ -922,7 +927,7 @@ bufferevent_rate_limit_group_decrement_read(
 	struct bufferevent_rate_limit_group *grp, ev_ssize_t decr)
 {
 	int r = 0;
-	ev_int32_t old_limit, new_limit;
+	ev_ssize_t old_limit, new_limit;
 	LOCK_GROUP(grp);
 	old_limit = grp->rate_limit.read_limit;
 	new_limit = (grp->rate_limit.read_limit -= decr);
@@ -942,7 +947,7 @@ bufferevent_rate_limit_group_decrement_write(
 	struct bufferevent_rate_limit_group *grp, ev_ssize_t decr)
 {
 	int r = 0;
-	ev_int32_t old_limit, new_limit;
+	ev_ssize_t old_limit, new_limit;
 	LOCK_GROUP(grp);
 	old_limit = grp->rate_limit.write_limit;
 	new_limit = (grp->rate_limit.write_limit -= decr);

include/event2/bufferevent.h

@@ -565,6 +565,9 @@ struct ev_token_bucket_cfg;
 */
 struct bufferevent_rate_limit_group;
 
+/** Maximum configurable rate- or burst-limit. */
+#define EV_RATE_LIMIT_MAX EV_SSIZE_MAX
+
 /**
    Initialize and return a new object to configure the rate-limiting behavior
    of bufferevents.
@@ -582,8 +585,8 @@ struct bufferevent_rate_limit_group;
    of Libevent may implement them more tightly.
  */
 struct ev_token_bucket_cfg *ev_token_bucket_cfg_new(
-	ev_uint32_t read_rate, ev_uint32_t read_burst,
+	size_t read_rate, size_t read_burst,
-	ev_uint32_t write_rate, ev_uint32_t write_burst,
+	size_t write_rate, size_t write_burst,
 	const struct timeval *tick_len);
 
 /** Free all storage held in 'cfg'.

ratelim-internal.h

@@ -38,7 +38,7 @@ extern "C" {
 struct ev_token_bucket {
 	/** How many bytes are we willing to read or write right now? These
 	 * values are signed so that we can do "defecit spending" */
-	ev_int32_t read_limit, write_limit;
+	ev_ssize_t read_limit, write_limit;
 	/** When was this bucket last updated?  Measured in abstract 'ticks'
 	 * relative to the token bucket configuration. */
 	ev_uint32_t last_updated;
@@ -47,13 +47,13 @@ struct ev_token_bucket {
 /** Configuration info for a token bucket or set of token buckets. */
 struct ev_token_bucket_cfg {
 	/** How many bytes are we willing to read on average per tick? */
-	ev_uint32_t read_rate;
+	size_t read_rate;
 	/** How many bytes are we willing to read at most in any one tick? */
-	ev_uint32_t read_maximum;
+	size_t read_maximum;
 	/** How many bytes are we willing to write on average per tick? */
-	ev_uint32_t write_rate;
+	size_t write_rate;
 	/** How many bytes are we willing to write at most in any one tick? */
-	ev_uint32_t write_maximum;
+	size_t write_maximum;
 
 	/* How long is a tick?  Note that fractions of a millisecond are
 	 * ignored. */