Do not have the MTU table twice in the code. Therefore move the

function from the timer code to util, rename it appropriately and
also fix a bug in sctp_get_prev_mtu(), where calling it with a
value existing in the MTU table did not return a smaller one.

MFC after: 3 days.

sys/netinet/sctp_timer.c

@@ -1670,46 +1670,6 @@ sctp_heartbeat_timer(struct sctp_inpcb *inp, struct sctp_tcb *stcb,
 	return (0);
 }
 
-#define SCTP_NUMBER_OF_MTU_SIZES 18
-static uint32_t mtu_sizes[] = {
-	68,
-	296,
-	508,
-	512,
-	544,
-	576,
-	1006,
-	1492,
-	1500,
-	1536,
-	2002,
-	2048,
-	4352,
-	4464,
-	8166,
-	17914,
-	32000,
-	65535
-};
-
-
-static uint32_t
-sctp_getnext_mtu(struct sctp_inpcb *inp, uint32_t cur_mtu)
-{
-	/* select another MTU that is just bigger than this one */
-	int i;
-
-	for (i = 0; i < SCTP_NUMBER_OF_MTU_SIZES; i++) {
-		if (cur_mtu < mtu_sizes[i]) {
-			/* no max_mtu is bigger than this one */
-			return (mtu_sizes[i]);
-		}
-	}
-	/* here return the highest allowable */
-	return (cur_mtu);
-}
-
-
 void
 sctp_pathmtu_timer(struct sctp_inpcb *inp,
     struct sctp_tcb *stcb,
@@ -1717,7 +1677,7 @@ sctp_pathmtu_timer(struct sctp_inpcb *inp,
 {
 	uint32_t next_mtu, mtu;
 
-	next_mtu = sctp_getnext_mtu(inp, net->mtu);
+	next_mtu = sctp_get_next_mtu(inp, net->mtu);
 
 	if ((next_mtu > net->mtu) && (net->port == 0)) {
 		if ((net->src_addr_selected == 0) ||

sys/netinet/sctp_usrreq.c

@@ -194,7 +194,7 @@ sctp_notify_mbuf(struct sctp_inpcb *inp,
 		 * mtu is. Rats we will have to guess (in a educated fashion
 		 * of course)
 		 */
-		nxtsz = find_next_best_mtu(totsz);
+		nxtsz = sctp_get_prev_mtu(totsz);
 	}
 	/* Stop any PMTU timer */
 	if (SCTP_OS_TIMER_PENDING(&net->pmtu_timer.timer)) {

sys/netinet/sctputil.c

@@ -50,8 +50,6 @@ __FBSDID("$FreeBSD$");
 #include <netinet/sctp_cc_functions.h>
 #include <netinet/sctp_bsd_addr.h>
 
-#define NUMBER_OF_MTU_SIZES 18
-
 
 #ifndef KTR_SCTP
 #define KTR_SCTP KTR_SUBSYS
@@ -753,7 +751,7 @@ sctp_stop_timers_for_shutdown(struct sctp_tcb *stcb)
  * a list of sizes based on typical mtu's, used only if next hop size not
  * returned.
  */
-static int sctp_mtu_sizes[] = {
+static uint32_t sctp_mtu_sizes[] = {
 	68,
 	296,
 	508,
@@ -774,25 +772,42 @@ static int sctp_mtu_sizes[] = {
 	65535
 };
 
-int
-find_next_best_mtu(int totsz)
-{
-	int i, perfer;
-
 /*
-	 * if we are in here we must find the next best fit based on the
+ * Return the largest MTU smaller than val. If there is no
-	 * size of the dg that failed to be sent.
+ * entry, just return val.
  */
-	perfer = 0;
+uint32_t
-	for (i = 0; i < NUMBER_OF_MTU_SIZES; i++) {
+sctp_get_prev_mtu(uint32_t val)
-		if (totsz < sctp_mtu_sizes[i]) {
+{
-			perfer = i - 1;
+	uint32_t i;
-			if (perfer < 0)
+
-				perfer = 0;
+	if (val <= sctp_mtu_sizes[0]) {
+		return (val);
+	}
+	for (i = 1; i < (sizeof(sctp_mtu_sizes) / sizeof(uint32_t)); i++) {
+		if (val <= sctp_mtu_sizes[i]) {
 			break;
 		}
 	}
-	return (sctp_mtu_sizes[perfer]);
+	return (sctp_mtu_sizes[i - 1]);
+}
+
+/*
+ * Return the smallest MTU larger than val. If there is no
+ * entry, just return val.
+ */
+uint32_t
+sctp_get_next_mtu(struct sctp_inpcb *inp, uint32_t val)
+{
+	/* select another MTU that is just bigger than this one */
+	uint32_t i;
+
+	for (i = 0; i < (sizeof(sctp_mtu_sizes) / sizeof(uint32_t)); i++) {
+		if (val < sctp_mtu_sizes[i]) {
+			return (sctp_mtu_sizes[i]);
+		}
+	}
+	return (val);
 }
 
 void

sys/netinet/sctputil.h

@@ -124,7 +124,8 @@ sctp_append_to_readq(struct sctp_inpcb *inp,
 
 void sctp_iterator_worker(void);
 
-int find_next_best_mtu(int);
+uint32_t sctp_get_prev_mtu(uint32_t);
+uint32_t sctp_get_next_mtu(struct sctp_inpcb *, uint32_t);
 
 void
      sctp_timeout_handler(void *);