lib: updates to zapi_route

This patch introduces the following changes to the zapi_route structure
and associated code:
* Use a fixed-size array to store the nexthops instead of a pointer. This
  makes the zapi_route() function much easier to use when we have multiple
  nexthops to send. It's also much more efficient to put everything on
  the stack rather than allocating an array in the heap every time we
  need to send a route to zebra;

* Use the new 'zapi_nexthop' structure. This will allow the client daemons
  to send labeled routes without having to allocate memory for the labels
  (the 'nexthop' structure was designed to be memory efficient and doesn't
  have room for MPLS labels, only a pointer). Also, 'zapi_nexthop' is more
  compact and more clean from an API perspective;

* Embed the route prefix inside the zapi_route structure. Since the
  route's prefix is sent along with its nexthops and attributes, it makes
  sense to pack everything inside the same structure.

Signed-off-by: Renato Westphal <renato@opensourcerouting.org>

1 files changed, 37 insertions, 47 deletions

diff --git a/lib/zclient.c b/lib/zclient.c
index f8bbdd85c9..53e8569b77 100644
--- a/lib/zclient.c
+++ b/lib/zclient.c
@@ -892,16 +892,12 @@ int zapi_ipv6_route(u_char cmd, struct zclient *zclient, struct prefix_ipv6 *p,
 	return zclient_send_message(zclient);
 }
 
-int zapi_route(u_char cmd, struct zclient *zclient, struct prefix *p,
-	       struct prefix_ipv6 *src_p, struct zapi_route *api)
+int zapi_route(u_char cmd, struct zclient *zclient, struct zapi_route *api)
 {
 	int i;
 	int psize;
 	struct stream *s;
-
-	/* either we have !SRCPFX && src_p == NULL, or SRCPFX && src_p != NULL
-	 */
-	assert(!(api->message & ZAPI_MESSAGE_SRCPFX) == !src_p);
+	struct zapi_nexthop *api_nh;
 
 	/* Reset stream. */
 	s = zclient->obuf;
@@ -917,69 +913,63 @@ int zapi_route(u_char cmd, struct zclient *zclient, struct prefix *p,
 	stream_putw(s, api->safi);
 
 	/* Put prefix information. */
-	psize = PSIZE(p->prefixlen);
-	stream_putc(s, p->prefixlen);
-	stream_write(s, (u_char *)&p->u.prefix, psize);
+	psize = PSIZE(api->prefix.prefixlen);
+	stream_putc(s, api->prefix.prefixlen);
+	stream_write(s, (u_char *)&api->prefix.u.prefix, psize);
 
 	if (CHECK_FLAG(api->message, ZAPI_MESSAGE_SRCPFX)) {
-		psize = PSIZE(src_p->prefixlen);
-		stream_putc(s, src_p->prefixlen);
-		stream_write(s, (u_char *)&src_p->prefix, psize);
+		psize = PSIZE(api->src_prefix.prefixlen);
+		stream_putc(s, api->src_prefix.prefixlen);
+		stream_write(s, (u_char *)&api->src_prefix.prefix, psize);
 	}
 
 	/* Nexthop, ifindex, distance and metric information. */
 	if (CHECK_FLAG(api->message, ZAPI_MESSAGE_NEXTHOP)) {
+		/* limit the number of nexthops if necessary */
+		if (api->nexthop_num > MULTIPATH_NUM) {
+			char buf[PREFIX2STR_BUFFER];
+
+			prefix2str(&api->prefix, buf, sizeof(buf));
+			zlog_warn(
+				"%s: prefix %s: encoding %u nexthops out of %u",
+				__func__, buf, MULTIPATH_NUM, api->nexthop_num);
+			api->nexthop_num = MULTIPATH_NUM;
+		}
+
 		stream_putc(s, api->nexthop_num);
 
 		for (i = 0; i < api->nexthop_num; i++) {
-			stream_putc(s, api->nexthop[i]->type);
-			switch (api->nexthop[i]->type) {
+			api_nh = &api->nexthops[i];
+
+			stream_putc(s, api_nh->type);
+			switch (api_nh->type) {
 			case NEXTHOP_TYPE_BLACKHOLE:
 				break;
 			case NEXTHOP_TYPE_IPV4:
-				stream_put_in_addr(s,
-						   &api->nexthop[i]->gate.ipv4);
-
-				/* For labeled-unicast, each nexthop is followed
-				 * by label. */
-				if (CHECK_FLAG(api->message,
-					       ZAPI_MESSAGE_LABEL))
-					stream_putl(
-						s,
-						api->nexthop[i]
-							->nh_label->label[0]);
+				stream_put_in_addr(s, &api_nh->gate.ipv4);
 				break;
 			case NEXTHOP_TYPE_IPV4_IFINDEX:
-				stream_put_in_addr(s,
-						   &api->nexthop[i]->gate.ipv4);
-				stream_putl(s, api->nexthop[i]->ifindex);
+				stream_put_in_addr(s, &api_nh->gate.ipv4);
+				stream_putl(s, api_nh->ifindex);
 				break;
 			case NEXTHOP_TYPE_IFINDEX:
-				stream_putl(s, api->nexthop[i]->ifindex);
+				stream_putl(s, api_nh->ifindex);
 				break;
 			case NEXTHOP_TYPE_IPV6:
-				stream_write(
-					s,
-					(u_char *)&api->nexthop[i]->gate.ipv6,
-					16);
-
-				/* For labeled-unicast, each nexthop is followed
-				 * by label. */
-				if (CHECK_FLAG(api->message,
-					       ZAPI_MESSAGE_LABEL))
-					stream_putl(
-						s,
-						api->nexthop[i]
-							->nh_label->label[0]);
+				stream_write(s, (u_char *)&api_nh->gate.ipv6,
+					     16);
 				break;
 			case NEXTHOP_TYPE_IPV6_IFINDEX:
-				stream_write(
-					s,
-					(u_char *)&api->nexthop[i]->gate.ipv6,
-					16);
-				stream_putl(s, api->nexthop[i]->ifindex);
+				stream_write(s, (u_char *)&api_nh->gate.ipv6,
+					     16);
+				stream_putl(s, api_nh->ifindex);
 				break;
 			}
+
+			/* For labeled-unicast, each nexthop is followed
+			 * by label. */
+			if (CHECK_FLAG(api->message, ZAPI_MESSAGE_LABEL))
+				stream_putl(s, api_nh->label);
 		}
 	}