zebra: add inbound netlink socket for dataplane

Add a new netlink socket for events coming in from the host OS
to the dataplane system for processing. Rename the existing
outbound dplane socket.

Signed-off-by: Mark Stapp <mjs.ietf@gmail.com>

4 files changed, 60 insertions, 23 deletions

diff --git a/zebra/kernel_netlink.c b/zebra/kernel_netlink.c
index effec24c1..b4bf18f25 100644
--- a/zebra/kernel_netlink.c
+++ b/zebra/kernel_netlink.c
@@ -477,7 +477,8 @@ static void netlink_install_filter(int sock, __u32 pid, __u32 dplane_pid)
 }
 
 void netlink_parse_rtattr_flags(struct rtattr **tb, int max,
-		struct rtattr *rta, int len, unsigned short flags)
+				struct rtattr *rta, int len,
+				unsigned short flags)
 {
 	unsigned short type;
 
@@ -1455,12 +1456,25 @@ void kernel_init(struct zebra_ns *zns)
 		exit(-1);
 	}
 
-	snprintf(zns->netlink_dplane.name, sizeof(zns->netlink_dplane.name),
-		 "netlink-dp (NS %u)", zns->ns_id);
-	zns->netlink_dplane.sock = -1;
-	if (netlink_socket(&zns->netlink_dplane, 0, zns->ns_id) < 0) {
+	/* Outbound socket for dplane programming of the host OS. */
+	snprintf(zns->netlink_dplane_out.name,
+		 sizeof(zns->netlink_dplane_out.name), "netlink-dp (NS %u)",
+		 zns->ns_id);
+	zns->netlink_dplane_out.sock = -1;
+	if (netlink_socket(&zns->netlink_dplane_out, 0, zns->ns_id) < 0) {
 		zlog_err("Failure to create %s socket",
-			 zns->netlink_dplane.name);
+			 zns->netlink_dplane_out.name);
+		exit(-1);
+	}
+
+	/* Inbound socket for OS events coming to the dplane. */
+	snprintf(zns->netlink_dplane_in.name,
+		 sizeof(zns->netlink_dplane_in.name), "netlink-dp-in (NS %u)",
+		 zns->ns_id);
+	zns->netlink_dplane_in.sock = -1;
+	if (netlink_socket(&zns->netlink_dplane_in, groups, zns->ns_id) < 0) {
+		zlog_err("Failure to create %s socket",
+			 zns->netlink_dplane_in.name);
 		exit(-1);
 	}
 
@@ -1483,8 +1497,8 @@ void kernel_init(struct zebra_ns *zns)
 			    errno, safe_strerror(errno));
 
 	one = 1;
-	ret = setsockopt(zns->netlink_dplane.sock, SOL_NETLINK, NETLINK_EXT_ACK,
-			 &one, sizeof(one));
+	ret = setsockopt(zns->netlink_dplane_out.sock, SOL_NETLINK,
+			 NETLINK_EXT_ACK, &one, sizeof(one));
 
 	if (ret < 0)
 		zlog_notice("Registration for extended dp ACK failed : %d %s",
@@ -1496,8 +1510,8 @@ void kernel_init(struct zebra_ns *zns)
 	 * setsockopt fails, ignore the error.
 	 */
 	one = 1;
-	ret = setsockopt(zns->netlink_dplane.sock, SOL_NETLINK, NETLINK_CAP_ACK,
-			 &one, sizeof(one));
+	ret = setsockopt(zns->netlink_dplane_out.sock, SOL_NETLINK,
+			 NETLINK_CAP_ACK, &one, sizeof(one));
 	if (ret < 0)
 		zlog_notice(
 			"Registration for reduced ACK packet size failed, probably running an early kernel");
@@ -1512,20 +1526,33 @@ void kernel_init(struct zebra_ns *zns)
 		zlog_err("Can't set %s socket error: %s(%d)",
 			 zns->netlink_cmd.name, safe_strerror(errno), errno);
 
-	if (fcntl(zns->netlink_dplane.sock, F_SETFL, O_NONBLOCK) < 0)
+	if (fcntl(zns->netlink_dplane_out.sock, F_SETFL, O_NONBLOCK) < 0)
 		zlog_err("Can't set %s socket error: %s(%d)",
-			 zns->netlink_dplane.name, safe_strerror(errno), errno);
+			 zns->netlink_dplane_out.name, safe_strerror(errno),
+			 errno);
+
+	if (fcntl(zns->netlink_dplane_in.sock, F_SETFL, O_NONBLOCK) < 0)
+		zlog_err("Can't set %s socket error: %s(%d)",
+			 zns->netlink_dplane_in.name, safe_strerror(errno),
+			 errno);
 
 	/* Set receive buffer size if it's set from command line */
 	if (nl_rcvbufsize) {
 		netlink_recvbuf(&zns->netlink, nl_rcvbufsize);
 		netlink_recvbuf(&zns->netlink_cmd, nl_rcvbufsize);
-		netlink_recvbuf(&zns->netlink_dplane, nl_rcvbufsize);
+		netlink_recvbuf(&zns->netlink_dplane_out, nl_rcvbufsize);
+		netlink_recvbuf(&zns->netlink_dplane_in, nl_rcvbufsize);
 	}
 
-	netlink_install_filter(zns->netlink.sock,
+	/* Set filter for inbound sockets, to exclude events we've generated
+	 * ourselves.
+	 */
+	netlink_install_filter(zns->netlink.sock, zns->netlink_cmd.snl.nl_pid,
+			       zns->netlink_dplane_out.snl.nl_pid);
+
+	netlink_install_filter(zns->netlink_dplane_in.sock,
 			       zns->netlink_cmd.snl.nl_pid,
-			       zns->netlink_dplane.snl.nl_pid);
+			       zns->netlink_dplane_out.snl.nl_pid);
 
 	zns->t_netlink = NULL;
 
@@ -1549,13 +1576,18 @@ void kernel_terminate(struct zebra_ns *zns, bool complete)
 		zns->netlink_cmd.sock = -1;
 	}
 
+	if (zns->netlink_dplane_in.sock >= 0) {
+		close(zns->netlink_dplane_in.sock);
+		zns->netlink_dplane_in.sock = -1;
+	}
+
 	/* During zebra shutdown, we need to leave the dataplane socket
 	 * around until all work is done.
 	 */
 	if (complete) {
-		if (zns->netlink_dplane.sock >= 0) {
-			close(zns->netlink_dplane.sock);
-			zns->netlink_dplane.sock = -1;
+		if (zns->netlink_dplane_out.sock >= 0) {
+			close(zns->netlink_dplane_out.sock);
+			zns->netlink_dplane_out.sock = -1;
 		}
 	}
 }
diff --git a/zebra/zebra_dplane.c b/zebra/zebra_dplane.c
index 39f865fbf..eec972e5e 100644
--- a/zebra/zebra_dplane.c
+++ b/zebra/zebra_dplane.c
@@ -2177,9 +2177,9 @@ static int dplane_ctx_ns_init(struct zebra_dplane_ctx *ctx,
 	 * two messages in some 'update' cases.
 	 */
 	if (is_update)
-		zns->netlink_dplane.seq += 2;
+		zns->netlink_dplane_out.seq += 2;
 	else
-		zns->netlink_dplane.seq++;
+		zns->netlink_dplane_out.seq++;
 #endif	/* HAVE_NETLINK */
 
 	return AOK;
@@ -4709,7 +4709,7 @@ static void dplane_info_from_zns(struct zebra_dplane_info *ns_info,
 
 #if defined(HAVE_NETLINK)
 	ns_info->is_cmd = true;
-	ns_info->nls = zns->netlink_dplane;
+	ns_info->nls = zns->netlink_dplane_out;
 #endif /* NETLINK */
 }
 
diff --git a/zebra/zebra_fpm_netlink.c b/zebra/zebra_fpm_netlink.c
index 68fb04435..168e36ac9 100644
--- a/zebra/zebra_fpm_netlink.c
+++ b/zebra/zebra_fpm_netlink.c
@@ -281,7 +281,7 @@ static int netlink_route_info_fill(struct netlink_route_info *ri, int cmd,
 	ri->af = rib_dest_af(dest);
 
 	if (zvrf && zvrf->zns)
-		ri->nlmsg_pid = zvrf->zns->netlink_dplane.snl.nl_pid;
+		ri->nlmsg_pid = zvrf->zns->netlink_dplane_out.snl.nl_pid;
 
 	ri->nlmsg_type = cmd;
 	ri->rtm_table = table_info->table_id;
diff --git a/zebra/zebra_ns.h b/zebra/zebra_ns.h
index f7d1f4078..8237de7dd 100644
--- a/zebra/zebra_ns.h
+++ b/zebra/zebra_ns.h
@@ -52,7 +52,12 @@ struct zebra_ns {
 #ifdef HAVE_NETLINK
 	struct nlsock netlink;        /* kernel messages */
 	struct nlsock netlink_cmd;    /* command channel */
-	struct nlsock netlink_dplane; /* dataplane channel */
+
+	/* dplane system's channels: one for outgoing programming,
+	 * for the FIB e.g., and one for incoming events from the OS.
+	 */
+	struct nlsock netlink_dplane_out;
+	struct nlsock netlink_dplane_in;
 	struct thread *t_netlink;
 #endif