add a new control message to set sequence numbers on an uninitialized node.

Reviewed by:	archie
Approved by:	pjd (mentor)

3 files changed, 96 insertions, 3 deletions

diff --git a/share/man/man4/ng_l2tp.4 b/share/man/man4/ng_l2tp.4
index 7e4496d..a54cd3a 100644
--- a/share/man/man4/ng_l2tp.4
+++ b/share/man/man4/ng_l2tp.4
@@ -37,7 +37,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd April 22, 2002
+.Dd August 2, 2004
 .Dt NG_L2TP 4
 .Os
 .Sh NAME
@@ -273,6 +273,22 @@ The corresponding session hook must be connected.
 Same as
 .Dv NGM_L2TP_GET_STATS ,
 but also atomically clears the statistics as well.
+.It Dv NGM_L2TP_SET_SEQ
+This command sets the sequence numbers of a not yet enabled node.
+It takes a
+.Vt "struct ng_l2tp_seq_config"
+as argument, where
+.Va xack
+and
+.Va nr
+respectively
+.Va ns
+and
+.Va rack
+must be the same.
+This option is particularly useful if one receives and processes
+the first packet entirely in userspace and wants to hand over further
+processing to the node.
 .El
 .Sh SHUTDOWN
 This node shuts down upon receipt of a
diff --git a/sys/netgraph/ng_l2tp.c b/sys/netgraph/ng_l2tp.c
index b3b36c1..4d7efc7 100644
--- a/sys/netgraph/ng_l2tp.c
+++ b/sys/netgraph/ng_l2tp.c
@@ -171,6 +171,8 @@ static int	ng_l2tp_recv_data(node_p node, item_p item, hookpriv_p hpriv);
 static int	ng_l2tp_xmit_ctrl(priv_p priv, struct mbuf *m, u_int16_t ns);
 
 static void	ng_l2tp_seq_init(priv_p priv);
+static int	ng_l2tp_seq_set(priv_p priv,
+			const struct ng_l2tp_seq_config *conf);
 static int	ng_l2tp_seq_adjust(priv_p priv,
 			const struct ng_l2tp_config *conf);
 static void	ng_l2tp_seq_reset(priv_p priv);
@@ -187,6 +189,14 @@ static ng_fn_eachhook	ng_l2tp_reset_session;
 static void	ng_l2tp_seq_check(struct l2tp_seq *seq);
 #endif
 
+/* Parse type for struct ng_l2tp_seq_config. */
+static const struct ng_parse_struct_field
+	ng_l2tp_seq_config_fields[] = NG_L2TP_SEQ_CONFIG_TYPE_INFO;
+static const struct ng_parse_type ng_l2tp_seq_config_type = {
+	&ng_parse_struct_type,
+	&ng_l2tp_seq_config_fields
+};
+
 /* Parse type for struct ng_l2tp_config */
 static const struct ng_parse_struct_field
 	ng_l2tp_config_type_fields[] = NG_L2TP_CONFIG_TYPE_INFO;
@@ -269,6 +279,13 @@ static const struct ng_cmdlist ng_l2tp_cmdlist[] = {
 	  NULL,
 	  NULL
 	},
+	{
+	  NGM_L2TP_COOKIE,
+	  NGM_L2TP_SET_SEQ,
+	  "setsequence",
+	  &ng_l2tp_seq_config_type,
+	  NULL
+	},
 	{ 0 }
 };
 
@@ -457,7 +474,7 @@ ng_l2tp_rcvmsg(node_p node, item_p item, hook_p lasthook)
 			hookpriv_p hpriv;
 			hook_p hook;
 
-			/* Check for invalid or illegal config */
+			/* Check for invalid or illegal config. */
 			if (msg->header.arglen != sizeof(*conf)) {
 				error = EINVAL;
 				break;
@@ -536,6 +553,25 @@ ng_l2tp_rcvmsg(node_p node, item_p item, hook_p lasthook)
 				memset(&priv->stats, 0, sizeof(priv->stats));
 			break;
 		    }
+		case NGM_L2TP_SET_SEQ:
+		    {
+			struct ng_l2tp_seq_config *const conf =
+				(struct ng_l2tp_seq_config *)msg->data;
+
+			/* Check for invalid or illegal seq config. */
+			if (msg->header.arglen != sizeof(*conf)) {
+				error = EINVAL;
+				break;
+			}
+			conf->ns = htons(conf->ns);
+			conf->nr = htons(conf->nr);
+			conf->rack = htons(conf->rack);
+			conf->xack = htons(conf->xack);
+
+			/* Set sequence numbers. */
+			error = ng_l2tp_seq_set(priv, conf);
+			break;
+		    }
 		default:
 			error = EINVAL;
 			break;
@@ -1057,6 +1093,31 @@ ng_l2tp_seq_init(priv_p priv)
 }
 
 /*
+ * Set sequence number state as given from user.
+ */
+static int
+ng_l2tp_seq_set(priv_p priv, const struct ng_l2tp_seq_config *conf)
+{
+	struct l2tp_seq *const seq = &priv->seq;
+
+	/* If node is enabled, deny update to sequence numbers. */
+	if (priv->conf.enabled)
+		return (EBUSY);
+
+	/* We only can handle the simple cases. */
+	if (conf->xack != conf->nr || conf->ns != conf->rack)
+		return (EINVAL);
+
+	/* Set ns,nr,rack,xack parameters. */
+	seq->ns = conf->ns;
+	seq->nr = conf->nr;
+	seq->rack = conf->rack;
+	seq->xack = conf->xack;
+
+	return (0);
+}
+
+/*
  * Adjust sequence number state accordingly after reconfiguration.
  */
 static int
diff --git a/sys/netgraph/ng_l2tp.h b/sys/netgraph/ng_l2tp.h
index 4fe1d50..9ceb343 100644
--- a/sys/netgraph/ng_l2tp.h
+++ b/sys/netgraph/ng_l2tp.h
@@ -45,7 +45,7 @@
 
 /* Node type name and magic cookie */
 #define NG_L2TP_NODE_TYPE	"l2tp"
-#define NGM_L2TP_COOKIE		1011392401
+#define NGM_L2TP_COOKIE		1091448040
 
 /* Hook names */
 #define NG_L2TP_HOOK_CTRL	"ctrl"		/* control channel hook */
@@ -55,6 +55,21 @@
 #define NG_L2TP_HOOK_SESSION_P	"session_"	/* session data hook (prefix) */
 #define NG_L2TP_HOOK_SESSION_F	"session_%04x"	/* session data hook (format) */
 
+/* Set intial sequence numbers to not yet enabled node. */
+struct ng_l2tp_seq_config {
+	u_int16_t	ns;		/* sequence number to send next */
+	u_int16_t	nr;		/* sequence number to be recved next */
+	u_int16_t	rack;		/* last 'nr' received */
+	u_int16_t	xack;		/* last 'nr' sent */
+};
+
+/* Keep this in sync with the above structure definition. */
+#define	NG_L2TP_SEQ_CONFIG_TYPE_INFO	{			\
+	  { "ns",		&ng_parse_uint16_type	},	\
+	  { "nr",		&ng_parse_uint16_type	},	\
+	  { NULL }						\
+}
+
 /* Configuration for a node */
 struct ng_l2tp_config {
 	u_char		enabled;	/* enables traffic flow */
@@ -156,6 +171,7 @@ enum {
 	NGM_L2TP_CLR_STATS,		/* clears stats */
 	NGM_L2TP_GETCLR_STATS,		/* returns & clears stats */
 	NGM_L2TP_ACK_FAILURE,		/* sent *from* node after ack timeout */
+	NGM_L2TP_SET_SEQ		/* supply a struct ng_l2tp_seq_config */
 };
 
 #endif /* _NETGRAPH_NG_L2TP_H_ */