lib/zserv: introduce address-family independent ZAPI message types

As noticed in 657cde1, the zapi_ipv[4|6]_route functions are broken in
many ways and that's the reason that many client daemons (e.g. ospfd,
isisd) need to send handcrafted messages to zebra.

The zapi_route() function introduced by Donald solves the problem
by providing a consistent way to send ipv4/ipv6 routes to zebra with
nexthops of any type, in all possible combinations including IPv4 routes
with IPv6 nexthops (for BGP unnumbered routes).

This patch goes a bit further and creates two new address-family
independent ZAPI message types that the client daemons can
use to advertise route information to zebra: ZEBRA_ROUTE_ADD and
ZEBRA_ROUTE_DELETE. The big advantage of having address-family independent
messages is that it allows us to remove a lot of duplicate code in zebra
and in the client daemons.

This patch also introduces the zapi_route_decode() function. It will be
used by zebra to decode route messages sent by the client daemons using
zclient_route_send(), which calls zapi_route_encode().

Later on we'll use this same pair of encode/decode functions to
send/receive redistributed routes from zebra to the client daemons,
taking the idea of removing code duplication to the next level.

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

5 files changed, 262 insertions, 17 deletions

diff --git a/babeld/kernel.c b/babeld/kernel.c
index 105a7d0518..6cdd66e48d 100644
--- a/babeld/kernel.c
+++ b/babeld/kernel.c
@@ -190,9 +190,8 @@ kernel_route_v4(int add,
 
     debugf(BABEL_DEBUG_ROUTE, "%s route (ipv4) to zebra",
            add ? "adding" : "removing" );
-    return zapi_route (add ? ZEBRA_IPV4_ROUTE_ADD :
-                       ZEBRA_IPV4_ROUTE_DELETE,
-                       zclient, &api);
+    return zclient_route_send (add ? ZEBRA_ROUTE_ADD : ZEBRA_ROUTE_DELETE,
+                               zclient, &api);
 }
 
 static int
@@ -242,9 +241,8 @@ kernel_route_v6(int add, const unsigned char *pref, unsigned short plen,
 
     debugf(BABEL_DEBUG_ROUTE, "%s route (ipv6) to zebra",
            add ? "adding" : "removing" );
-    return zapi_route (add ? ZEBRA_IPV6_ROUTE_ADD :
-                       ZEBRA_IPV6_ROUTE_DELETE,
-                       zclient, &api);
+    return zclient_route_send (add ? ZEBRA_ROUTE_ADD : ZEBRA_ROUTE_DELETE,
+                               zclient, &api);
 }
 
 int
diff --git a/lib/log.c b/lib/log.c
index b9ce9e69bc..92b2d3b66b 100644
--- a/lib/log.c
+++ b/lib/log.c
@@ -867,6 +867,8 @@ static const struct zebra_desc_table command_types[] = {
 	DESC_ENTRY(ZEBRA_INTERFACE_UP),
 	DESC_ENTRY(ZEBRA_INTERFACE_DOWN),
 	DESC_ENTRY(ZEBRA_INTERFACE_SET_MASTER),
+	DESC_ENTRY(ZEBRA_ROUTE_ADD),
+	DESC_ENTRY(ZEBRA_ROUTE_DELETE),
 	DESC_ENTRY(ZEBRA_IPV4_ROUTE_ADD),
 	DESC_ENTRY(ZEBRA_IPV4_ROUTE_DELETE),
 	DESC_ENTRY(ZEBRA_IPV6_ROUTE_ADD),
diff --git a/lib/zclient.c b/lib/zclient.c
index 53e8569b77..3f5c7a0f6f 100644
--- a/lib/zclient.c
+++ b/lib/zclient.c
@@ -892,20 +892,23 @@ 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 zapi_route *api)
+int zclient_route_send(u_char cmd, struct zclient *zclient,
+		       struct zapi_route *api)
 {
+	if (zapi_route_encode(cmd, zclient->obuf, api) < 0)
+		return -1;
+	return zclient_send_message(zclient);
+}
+
+int zapi_route_encode(u_char cmd, struct stream *s, struct zapi_route *api)
+{
+	struct zapi_nexthop *api_nh;
 	int i;
 	int psize;
-	struct stream *s;
-	struct zapi_nexthop *api_nh;
 
-	/* Reset stream. */
-	s = zclient->obuf;
 	stream_reset(s);
-
 	zclient_create_header(s, cmd, api->vrf_id);
 
-	/* Put type and nexthop. */
 	stream_putc(s, api->type);
 	stream_putw(s, api->instance);
 	stream_putl(s, api->flags);
@@ -913,6 +916,7 @@ int zapi_route(u_char cmd, struct zclient *zclient, struct zapi_route *api)
 	stream_putw(s, api->safi);
 
 	/* Put prefix information. */
+	stream_putc(s, api->prefix.family);
 	psize = PSIZE(api->prefix.prefixlen);
 	stream_putc(s, api->prefix.prefixlen);
 	stream_write(s, (u_char *)&api->prefix.u.prefix, psize);
@@ -923,7 +927,7 @@ int zapi_route(u_char cmd, struct zclient *zclient, struct zapi_route *api)
 		stream_write(s, (u_char *)&api->src_prefix.prefix, psize);
 	}
 
-	/* Nexthop, ifindex, distance and metric information. */
+	/* Nexthops.  */
 	if (CHECK_FLAG(api->message, ZAPI_MESSAGE_NEXTHOP)) {
 		/* limit the number of nexthops if necessary */
 		if (api->nexthop_num > MULTIPATH_NUM) {
@@ -973,6 +977,7 @@ int zapi_route(u_char cmd, struct zclient *zclient, struct zapi_route *api)
 		}
 	}
 
+	/* Attributes. */
 	if (CHECK_FLAG(api->message, ZAPI_MESSAGE_DISTANCE))
 		stream_putc(s, api->distance);
 	if (CHECK_FLAG(api->message, ZAPI_MESSAGE_METRIC))
@@ -985,7 +990,100 @@ int zapi_route(u_char cmd, struct zclient *zclient, struct zapi_route *api)
 	/* Put length at the first point of the stream. */
 	stream_putw_at(s, 0, stream_get_endp(s));
 
-	return zclient_send_message(zclient);
+	return 0;
+}
+
+int zapi_route_decode(struct stream *s, struct zapi_route *api)
+{
+	struct zapi_nexthop *api_nh;
+	int i;
+
+	memset(api, 0, sizeof(*api));
+
+	/* Type, flags, message. */
+	api->type = stream_getc(s);
+	api->instance = stream_getw(s);
+	api->flags = stream_getl(s);
+	api->message = stream_getc(s);
+	api->safi = stream_getw(s);
+
+	/* Prefix. */
+	api->prefix.family = stream_getc(s);
+	switch (api->prefix.family) {
+	case AF_INET:
+		api->prefix.prefixlen = MIN(IPV4_MAX_PREFIXLEN, stream_getc(s));
+		break;
+	case AF_INET6:
+		api->prefix.prefixlen = MIN(IPV6_MAX_PREFIXLEN, stream_getc(s));
+		break;
+	}
+	stream_get(&api->prefix.u.prefix, s, PSIZE(api->prefix.prefixlen));
+	if (CHECK_FLAG(api->message, ZAPI_MESSAGE_SRCPFX)) {
+		api->src_prefix.family = AF_INET6;
+		api->src_prefix.prefixlen = stream_getc(s);
+		stream_get(&api->src_prefix.prefix, s,
+			   PSIZE(api->src_prefix.prefixlen));
+
+		if (api->prefix.family != AF_INET6
+		    || api->src_prefix.prefixlen == 0)
+			UNSET_FLAG(api->message, ZAPI_MESSAGE_SRCPFX);
+	}
+
+	/* Nexthops. */
+	if (CHECK_FLAG(api->message, ZAPI_MESSAGE_NEXTHOP)) {
+		api->nexthop_num = stream_getc(s);
+		if (api->nexthop_num > MULTIPATH_NUM) {
+			zlog_warn("%s: invalid number of nexthops (%u)",
+				  __func__, api->nexthop_num);
+			return -1;
+		}
+
+		for (i = 0; i < api->nexthop_num; i++) {
+			api_nh = &api->nexthops[i];
+
+			api_nh->type = stream_getc(s);
+			switch (api_nh->type) {
+			case NEXTHOP_TYPE_BLACKHOLE:
+				break;
+			case NEXTHOP_TYPE_IPV4:
+				api_nh->gate.ipv4.s_addr = stream_get_ipv4(s);
+				break;
+			case NEXTHOP_TYPE_IPV4_IFINDEX:
+				api_nh->gate.ipv4.s_addr = stream_get_ipv4(s);
+				api_nh->ifindex = stream_getl(s);
+				break;
+			case NEXTHOP_TYPE_IFINDEX:
+				api_nh->ifindex = stream_getl(s);
+				break;
+			case NEXTHOP_TYPE_IPV6:
+				stream_get(&api_nh->gate.ipv6, s, 16);
+				break;
+			case NEXTHOP_TYPE_IPV6_IFINDEX:
+				stream_get(&api_nh->gate.ipv6, s, 16);
+				api_nh->ifindex = stream_getl(s);
+				break;
+			}
+
+			/* For labeled-unicast, each nexthop is followed
+			 * by label. */
+			if (CHECK_FLAG(api->message, ZAPI_MESSAGE_LABEL)) {
+				stream_get(&api_nh->label, s,
+					   sizeof(api_nh->label));
+			}
+		}
+	}
+
+	/* Attributes. */
+	if (CHECK_FLAG(api->message, ZAPI_MESSAGE_DISTANCE))
+		api->distance = stream_getc(s);
+	if (CHECK_FLAG(api->message, ZAPI_MESSAGE_METRIC))
+		api->metric = stream_getl(s);
+	if (CHECK_FLAG(api->message, ZAPI_MESSAGE_TAG))
+		api->tag = stream_getl(s);
+	if (CHECK_FLAG(api->message, ZAPI_MESSAGE_MTU))
+		api->mtu = stream_getl(s);
+
+	return 0;
 }
 
 /*
diff --git a/lib/zclient.h b/lib/zclient.h
index 92aeabb07f..2e450ed398 100644
--- a/lib/zclient.h
+++ b/lib/zclient.h
@@ -59,6 +59,8 @@ typedef enum {
 	ZEBRA_INTERFACE_UP,
 	ZEBRA_INTERFACE_DOWN,
 	ZEBRA_INTERFACE_SET_MASTER,
+	ZEBRA_ROUTE_ADD,
+	ZEBRA_ROUTE_DELETE,
 	ZEBRA_IPV4_ROUTE_ADD,
 	ZEBRA_IPV4_ROUTE_DELETE,
 	ZEBRA_IPV6_ROUTE_ADD,
@@ -426,7 +428,8 @@ extern int zapi_ipv6_route(u_char cmd, struct zclient *zclient,
 extern int zapi_ipv4_route_ipv6_nexthop(u_char, struct zclient *,
 					struct prefix_ipv4 *,
 					struct zapi_ipv6 *);
-extern int zapi_route(u_char cmd, struct zclient *zclient,
-		      struct zapi_route *api);
+extern int zclient_route_send(u_char, struct zclient *, struct zapi_route *);
+extern int zapi_route_encode(u_char, struct stream *, struct zapi_route *);
+extern int zapi_route_decode(struct stream *, struct zapi_route *);
 
 #endif /* _ZEBRA_ZCLIENT_H */
diff --git a/zebra/zserv.c b/zebra/zserv.c
index e00e1d7c20..94e34865b5 100644
--- a/zebra/zserv.c
+++ b/zebra/zserv.c
@@ -1157,6 +1157,144 @@ void zserv_nexthop_num_warn(const char *caller, const struct prefix *p,
 	}
 }
 
+static int zread_route_add(struct zserv *client, u_short length,
+			   struct zebra_vrf *zvrf)
+{
+	struct stream *s;
+	struct zapi_route api;
+	struct zapi_nexthop *api_nh;
+	afi_t afi;
+	struct prefix_ipv6 *src_p = NULL;
+	struct route_entry *re;
+	struct nexthop *nexthop;
+	int i, ret;
+
+	s = client->ibuf;
+	if (zapi_route_decode(s, &api) < 0)
+		return -1;
+
+	/* Allocate new route. */
+	re = XCALLOC(MTYPE_RE, sizeof(struct route_entry));
+	re->type = api.type;
+	re->instance = api.instance;
+	re->flags = api.flags;
+	re->uptime = time(NULL);
+	re->vrf_id = zvrf_id(zvrf);
+	re->table = zvrf->table_id;
+
+	if (CHECK_FLAG(api.message, ZAPI_MESSAGE_NEXTHOP)) {
+		for (i = 0; i < api.nexthop_num; i++) {
+			api_nh = &api.nexthops[i];
+
+			switch (api_nh->type) {
+			case NEXTHOP_TYPE_IFINDEX:
+				route_entry_nexthop_ifindex_add(
+					re, api_nh->ifindex);
+				break;
+			case NEXTHOP_TYPE_IPV4:
+				nexthop = route_entry_nexthop_ipv4_add(
+					re, &api_nh->gate.ipv4, NULL);
+				break;
+			case NEXTHOP_TYPE_IPV4_IFINDEX:
+				nexthop = route_entry_nexthop_ipv4_ifindex_add(
+					re, &api_nh->gate.ipv4, NULL,
+					api_nh->ifindex);
+				break;
+			case NEXTHOP_TYPE_IPV6:
+				nexthop = route_entry_nexthop_ipv6_add(
+					re, &api_nh->gate.ipv6);
+				break;
+			case NEXTHOP_TYPE_IPV6_IFINDEX:
+				nexthop = route_entry_nexthop_ipv6_ifindex_add(
+					re, &api_nh->gate.ipv6,
+					api_nh->ifindex);
+				break;
+			case NEXTHOP_TYPE_BLACKHOLE:
+				route_entry_nexthop_blackhole_add(re);
+				break;
+			}
+
+			/* MPLS labels for BGP-LU or Segment Routing */
+			if (CHECK_FLAG(api.message, ZAPI_MESSAGE_LABEL)
+			    && api_nh->type != NEXTHOP_TYPE_IFINDEX
+			    && api_nh->type != NEXTHOP_TYPE_BLACKHOLE) {
+				enum lsp_types_t label_type;
+
+				label_type =
+					lsp_type_from_re_type(client->proto);
+				nexthop_add_labels(nexthop, label_type, 1,
+						   &api_nh->label);
+			}
+		}
+	}
+
+	if (CHECK_FLAG(api.message, ZAPI_MESSAGE_DISTANCE))
+		re->distance = api.distance;
+	if (CHECK_FLAG(api.message, ZAPI_MESSAGE_METRIC))
+		re->metric = api.metric;
+	if (CHECK_FLAG(api.message, ZAPI_MESSAGE_TAG))
+		re->tag = api.tag;
+	if (CHECK_FLAG(api.message, ZAPI_MESSAGE_MTU))
+		re->mtu = api.mtu;
+
+	afi = family2afi(api.prefix.family);
+	if (CHECK_FLAG(api.message, ZAPI_MESSAGE_SRCPFX))
+		src_p = &api.src_prefix;
+
+	ret = rib_add_multipath(afi, api.safi, &api.prefix, src_p, re);
+
+	/* Stats */
+	switch (api.prefix.family) {
+	case AF_INET:
+		if (ret > 0)
+			client->v4_route_add_cnt++;
+		else if (ret < 0)
+			client->v4_route_upd8_cnt++;
+		break;
+	case AF_INET6:
+		if (ret > 0)
+			client->v6_route_add_cnt++;
+		else if (ret < 0)
+			client->v6_route_upd8_cnt++;
+		break;
+	}
+
+	return 0;
+}
+
+static int zread_route_del(struct zserv *client, u_short length,
+			   struct zebra_vrf *zvrf)
+{
+	struct stream *s;
+	struct zapi_route api;
+	afi_t afi;
+	struct prefix_ipv6 *src_p = NULL;
+
+	s = client->ibuf;
+	if (zapi_route_decode(s, &api) < 0)
+		return -1;
+
+	afi = family2afi(api.prefix.family);
+	if (CHECK_FLAG(api.message, ZAPI_MESSAGE_SRCPFX))
+		src_p = &api.src_prefix;
+
+	rib_delete(afi, api.safi, zvrf_id(zvrf), api.type, api.instance,
+		   api.flags, &api.prefix, src_p, NULL, 0, zvrf->table_id,
+		   api.metric);
+
+	/* Stats */
+	switch (api.prefix.family) {
+	case AF_INET:
+		client->v4_route_del_cnt++;
+		break;
+	case AF_INET6:
+		client->v6_route_del_cnt++;
+		break;
+	}
+
+	return 0;
+}
+
 /* This function support multiple nexthop. */
 /*
  * Parse the ZEBRA_IPV4_ROUTE_ADD sent from client. Update re and
@@ -2334,6 +2472,12 @@ static int zebra_client_read(struct thread *thread)
 	case ZEBRA_INTERFACE_DELETE:
 		zread_interface_delete(client, length, zvrf);
 		break;
+	case ZEBRA_ROUTE_ADD:
+		zread_route_add(client, length, zvrf);
+		break;
+	case ZEBRA_ROUTE_DELETE:
+		zread_route_del(client, length, zvrf);
+		break;
 	case ZEBRA_IPV4_ROUTE_ADD:
 		zread_ipv4_add(client, length, zvrf);
 		break;