Analogous to the previous patch, this adds code to interpret incoming Confirm

feature-negotiation options. Both functions operate on the feature-negotiation

list of either the request_sock (server) or the dccp_sock (client).
Signed-off-by: Gerrit Renker

Acked-by: Ian McDonald

---

 net/dccp/feat.c    |   99 +++++++++++++++++++++++++++++++++++++++++++++++++++-

 net/dccp/feat.h    |    2 -

 net/dccp/options.c |   16 +-------

 3 files changed, 100 insertions(+), 17 deletions(-)
--- a/net/dccp/feat.c

+++ b/net/dccp/feat.c

@@ -99,6 +99,13 @@ static int dccp_feat_default_value(u8 feat_num)

 	return idx < 0 ? : dccp_feat_table[idx].default_value;

 }
+/* Test for "Req'd" feature (RFC 4340, 6.4) */

+static inline int dccp_feat_must_be_understood(u8 feat_num)

+{

+	return	feat_num == DCCPF_CCID || feat_num == DCCPF_SHORT_SEQNOS ||

+		feat_num == DCCPF_SEQUENCE_WINDOW;

+}

+

 /* copy constructor, fval must not already contain allocated memory */

 static int dccp_feat_clone_sp_val(dccp_feat_val *fval, u8 const *val, u8 len)

 {

@@ -1090,7 +1097,6 @@ int dccp_feat_change_recv(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)

 }
 EXPORT_SYMBOL_GPL(dccp_feat_change_recv);

-#endif	/* (later) */
 int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature,

 			   u8 *val, u8 len)

@@ -1145,6 +1151,7 @@ int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature,

 }
 EXPORT_SYMBOL_GPL(dccp_feat_confirm_recv);

+#endif	/* (later) */
 void dccp_feat_clean(struct dccp_minisock *dmsk)

 {

@@ -1343,6 +1350,92 @@ not_valid_or_not_known:

 }
 /**

+ * dccp_feat_confirm_recv  -  Process received Confirm options

+ * @fn: feature-negotiation list to update

+ * @is_mandatory: whether @opt was preceded by a Mandatory option

+ * @opt: %DCCPO_CONFIRM_L or %DCCPO_CONFIRM_R

+ * @feat: one of %dccp_feature_numbers

+ * @val: NN value or SP value/preference list

+ * @len: length of @val in bytes

+ * @server: whether this node is server (1) or client (0)

+ */

+static u8 dccp_feat_confirm_recv(struct list_head *fn, u8 is_mandatory, u8 opt,

+				 u8 feat, u8 *val, u8 len, const bool server)

+{

+	u8 *plist, plen, type = dccp_feat_type(feat);

+	const bool local = (opt == DCCPO_CONFIRM_R);

+	struct dccp_feat_entry *entry = dccp_feat_list_lookup(fn, feat, local);

+

+	if (entry == NULL) {	/* nothing queued: ignore or handle error */

+		if (is_mandatory && type == FEAT_UNKNOWN)

+			return DCCP_RESET_CODE_MANDATORY_ERROR;

+

+		if (!local && type == FEAT_NN)		/* 6.3.2 */

+			goto confirmation_failed;

+		return 0;

+	}

+

+	if (entry->state != FEAT_CHANGING)		/* 6.6.2 */

+		return 0;

+

+	if (len == 0) {

+		if (dccp_feat_must_be_understood(feat))	/* 6.6.7 */

+			goto confirmation_failed;

+		/*

+		 * Empty Confirm during connection setup: this means reverting

+		 * to the `old' value, which in this case is the default. Since

+		 * we handle default values automatically when no other values

+		 * have been set, we revert to the old value by removing this

+		 * entry from the list.

+		 */

+		dccp_feat_list_pop(entry);

+		return 0;

+	}

+

+	if (type == FEAT_NN) {

+		if (len > sizeof(entry->val.nn))

+			goto confirmation_failed;

+

+		if (entry->val.nn == dccp_decode_value_var(val, len))

+			goto confirmation_succeeded;

+

+		DCCP_WARN("Bogus Confirm for non-existing value\n");

+		goto confirmation_failed;

+	}

+

+	/*

+	 * Parsing SP Confirms: the first element of @val is the preferred

+	 * SP value which the peer confirms, the remainder depends on @len.

+	 */

+	if (!dccp_feat_sp_list_ok(feat, val, len))

+		goto confirmation_failed;

+

+	if (len == 1) {		/* peer didn't supply a preference list */

+		plist = val;

+		plen  = len;

+	} else {		/* preferred value + preference list */

+		plist = val + 1;

+		plen  = len - 1;

+	}

+

+	/* Check whether the peer got the reconciliation right (6.6.8) */

+	if (dccp_feat_reconcile(&entry->val, plist, plen, server, 0) != *val) {

+		DCCP_WARN("Confirm selected the wrong value %u\n", *val);

+		return DCCP_RESET_CODE_OPTION_ERROR;

+	}

+	entry->val.sp.vec[0] = *val;

+

+confirmation_succeeded:

+	entry->state = FEAT_STABLE;

+	return 0;

+

+confirmation_failed:

+	DCCP_WARN("Confirmation failed\n");

+	return is_mandatory ? DCCP_RESET_CODE_MANDATORY_ERROR

+			    : DCCP_RESET_CODE_OPTION_ERROR;

+}

+

+/**

  * dccp_feat_parse_options  -  Process Feature-Negotiation Options

  * @sk: for general use and used by the client during connection setup

  * @dreq: used by the server during connection setup

@@ -1372,6 +1465,10 @@ int dccp_feat_parse_options(struct sock *sk, struct dccp_request_sock *dreq,

 		case DCCPO_CHANGE_R:

 			return dccp_feat_change_recv(fn, mandatory, opt, feat,

 						     val, len, server);

+		case DCCPO_CONFIRM_R:

+		case DCCPO_CONFIRM_L:

+			return dccp_feat_confirm_recv(fn, mandatory, opt, feat,

+						      val, len, server);

 		}

 	}

 	return 0;	/* ignore FN options in all other states */

--- a/net/dccp/feat.h

+++ b/net/dccp/feat.h

@@ -115,8 +115,6 @@ extern int  dccp_feat_register_sp(struct sock *sk, u8 feat, u8 is_local,

 extern int  dccp_feat_register_nn(struct sock *sk, u8 feat, u64 val);

 extern int  dccp_feat_parse_options(struct sock *, struct dccp_request_sock *,

 				    u8 mand, u8 opt, u8 feat, u8 *val, u8 len);

-extern int  dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature,

-				   u8 *val, u8 len);

 extern void dccp_feat_clean(struct dccp_minisock *dmsk);

 extern int  dccp_feat_clone(struct sock *oldsk, struct sock *newsk);

 extern int  dccp_feat_clone_list(struct list_head const *, struct list_head *);

--- a/net/dccp/options.c

+++ b/net/dccp/options.c

@@ -134,26 +134,14 @@ int dccp_parse_options(struct sock *sk, struct dccp_request_sock *dreq,

 			dccp_pr_debug("%s opt: NDP count=%llu\n", dccp_role(sk),

 				      (unsigned long long)opt_recv->dccpor_ndp);

 			break;

-		case DCCPO_CHANGE_L:

-		case DCCPO_CHANGE_R:

-			if (pkt_type == DCCP_PKT_DATA)

+		case DCCPO_CHANGE_L ... DCCPO_CONFIRM_R:

+			if (pkt_type == DCCP_PKT_DATA)      /* RFC 4340, 6 */

 				break;

 			rc = dccp_feat_parse_options(sk, dreq, mandatory, opt,

 						    *value, value + 1, len - 1);

 			if (rc)

 				goto out_featneg_failed;

 			break;

-		case DCCPO_CONFIRM_L:

-			/* fall through */

-		case DCCPO_CONFIRM_R:

-			if (pkt_type == DCCP_PKT_DATA)

-				break;

-			if (len < 2)	/* FIXME this disallows empty confirm */

-				goto out_invalid_option;

-			if (dccp_feat_confirm_recv(sk, opt, *value,

-						   value + 1, len - 1))

-				goto out_invalid_option;

-			break;

 		case DCCPO_ACK_VECTOR_0:

 		case DCCPO_ACK_VECTOR_1:

 			if (dccp_packet_without_ack(skb))   /* RFC 4340, 11.4 */

--

1.6.0.rc2
--

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