dccp: Process incoming Change feature-negotiation options (e77b8363) · Commits · 戴 / test

net/dccp/feat.c

+179 −1

Original line number	Original line	Diff line number	Diff line
	@@ -237,6 +237,40 @@ static int dccp_feat_push_change(struct list_head *fn_list, u8 feat, u8 local,
	return 0;		return 0;
	}		}

			/**
			* dccp_feat_push_confirm - Add a Confirm entry to the FN list
			* @fn_list: feature-negotiation list to add to
			* @feat: one of %dccp_feature_numbers
			* @local: whether local (1) or remote (0) @feat_num is being confirmed
			* @fval: pointer to NN/SP value to be inserted or NULL
			* Returns 0 on success, a Reset code for further processing otherwise.
			*/
			static int dccp_feat_push_confirm(struct list_head *fn_list, u8 feat, u8 local,
			dccp_feat_val *fval)
			{
			struct dccp_feat_entry *new = dccp_feat_entry_new(fn_list, feat, local);

			if (new == NULL)
			return DCCP_RESET_CODE_TOO_BUSY;

			new->feat_num = feat;
			new->is_local = local;
			new->state = FEAT_STABLE; /* transition in 6.6.2 */
			new->needs_confirm = 1;
			new->empty_confirm = (fval == NULL);
			new->val.nn = 0; /* zeroes the whole structure */
			if (!new->empty_confirm)
			new->val = *fval;
			new->needs_mandatory = 0;

			return 0;
			}

			static int dccp_push_empty_confirm(struct list_head *fn_list, u8 feat, u8 local)
			{
			return dccp_feat_push_confirm(fn_list, feat, local, NULL);
			}

	static inline void dccp_feat_list_pop(struct dccp_feat_entry *entry)		static inline void dccp_feat_list_pop(struct dccp_feat_entry *entry)
	{		{
	list_del(&entry->node);		list_del(&entry->node);
	@@ -955,7 +989,6 @@ static int dccp_feat_nn(struct sock sk, u8 type, u8 feature, u8 val, u8 len)

	return 0;		return 0;
	}		}
	#endif /* (later) */

	static void dccp_feat_empty_confirm(struct dccp_minisock *dmsk,		static void dccp_feat_empty_confirm(struct dccp_minisock *dmsk,
	u8 type, u8 feature)		u8 type, u8 feature)
	@@ -1066,6 +1099,7 @@ int dccp_feat_change_recv(struct sock sk, u8 type, u8 feature, u8 val, u8 len)
	}		}

	EXPORT_SYMBOL_GPL(dccp_feat_change_recv);		EXPORT_SYMBOL_GPL(dccp_feat_change_recv);
			#endif /* (later) */

	int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature,		int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature,
	u8 *val, u8 len)		u8 *val, u8 len)
	@@ -1206,6 +1240,150 @@ out_clean:

	EXPORT_SYMBOL_GPL(dccp_feat_clone);		EXPORT_SYMBOL_GPL(dccp_feat_clone);

			/**
			* dccp_feat_change_recv - Process incoming ChangeL/R options
			* @fn: feature-negotiation list to update
			* @is_mandatory: whether the Change was preceded by a Mandatory option
			* @opt: %DCCPO_CHANGE_L or %DCCPO_CHANGE_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 the server (1) or the client (0)
			*/
			static u8 dccp_feat_change_recv(struct list_head *fn, u8 is_mandatory, u8 opt,
			u8 feat, u8 *val, u8 len, const bool server)
			{
			u8 defval, type = dccp_feat_type(feat);
			const bool local = (opt == DCCPO_CHANGE_R);
			struct dccp_feat_entry *entry;
			dccp_feat_val fval;

			if (len == 0 \|\| type == FEAT_UNKNOWN) /* 6.1 and 6.6.8 */
			goto unknown_feature_or_value;

			/*
			* Negotiation of NN features: Change R is invalid, so there is no
			* simultaneous negotiation; hence we do not look up in the list.
			*/
			if (type == FEAT_NN) {
			if (local \|\| len > sizeof(fval.nn))
			goto unknown_feature_or_value;

			/* 6.3.2: "The feature remote MUST accept any valid value..." */
			fval.nn = dccp_decode_value_var(val, len);
			if (!dccp_feat_is_valid_nn_val(feat, fval.nn))
			goto unknown_feature_or_value;

			return dccp_feat_push_confirm(fn, feat, local, &fval);
			}

			/*
			* Unidirectional/simultaneous negotiation of SP features (6.3.1)
			*/
			entry = dccp_feat_list_lookup(fn, feat, local);
			if (entry == NULL) {
			/*
			* No particular preferences have been registered. We deal with
			* this situation by assuming that all valid values are equally
			* acceptable, and apply the following checks:
			* - if the peer's list is a singleton, we accept a valid value;
			* - if we are the server, we first try to see if the peer (the
			* client) advertises the default value. If yes, we use it,
			* otherwise we accept the preferred value;
			* - else if we are the client, we use the first list element.
			*/
			if (dccp_feat_clone_sp_val(&fval, val, 1))
			return DCCP_RESET_CODE_TOO_BUSY;

			if (len > 1 && server) {
			defval = dccp_feat_default_value(feat);
			if (dccp_feat_preflist_match(&defval, 1, val, len) > -1)
			fval.sp.vec[0] = defval;
			} else if (!dccp_feat_is_valid_sp_val(feat, fval.sp.vec[0])) {
			kfree(fval.sp.vec);
			goto unknown_feature_or_value;
			}

			/* Treat unsupported CCIDs like invalid values */
			if (feat == DCCPF_CCID && !ccid_support_check(fval.sp.vec, 1)) {
			kfree(fval.sp.vec);
			goto not_valid_or_not_known;
			}

			return dccp_feat_push_confirm(fn, feat, local, &fval);

			} else if (entry->state == FEAT_UNSTABLE) { /* 6.6.2 */
			return 0;
			}

			if (dccp_feat_reconcile(&entry->val, val, len, server, true)) {
			entry->empty_confirm = 0;
			} else if (is_mandatory) {
			return DCCP_RESET_CODE_MANDATORY_ERROR;
			} else if (entry->state == FEAT_INITIALISING) {
			/*
			* Failed simultaneous negotiation (server only): try to `save'
			* the connection by checking whether entry contains the default
			* value for @feat. If yes, send an empty Confirm to signal that
			* the received Change was not understood - which implies using
			* the default value.
			* If this also fails, we use Reset as the last resort.
			*/
			WARN_ON(!server);
			defval = dccp_feat_default_value(feat);
			if (!dccp_feat_reconcile(&entry->val, &defval, 1, server, true))
			return DCCP_RESET_CODE_OPTION_ERROR;
			entry->empty_confirm = 1;
			}
			entry->needs_confirm = 1;
			entry->needs_mandatory = 0;
			entry->state = FEAT_STABLE;
			return 0;

			unknown_feature_or_value:
			if (!is_mandatory)
			return dccp_push_empty_confirm(fn, feat, local);

			not_valid_or_not_known:
			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
			* @mandatory: whether @opt was preceded by a Mandatory option
			* @opt: %DCCPO_CHANGE_L \| %DCCPO_CHANGE_R \| %DCCPO_CONFIRM_L \| %DCCPO_CONFIRM_R
			* @feat: one of %dccp_feature_numbers
			* @val: value contents of @opt
			* @len: length of @val in bytes
			* Returns 0 on success, a Reset code for ending the connection otherwise.
			*/
			int dccp_feat_parse_options(struct sock sk, struct dccp_request_sock dreq,
			u8 mandatory, u8 opt, u8 feat, u8 *val, u8 len)
			{
			struct dccp_sock *dp = dccp_sk(sk);
			struct list_head *fn = dreq ? &dreq->dreq_featneg : &dp->dccps_featneg;
			bool server = false;

			switch (sk->sk_state) {
			/*
			* Negotiation during connection setup
			*/
			case DCCP_LISTEN:
			server = true; /* fall through */
			case DCCP_REQUESTING:
			switch (opt) {
			case DCCPO_CHANGE_L:
			case DCCPO_CHANGE_R:
			return dccp_feat_change_recv(fn, mandatory, opt, feat,
			val, len, server);
			}
			}
			return 0; /* ignore FN options in all other states */
			}

	int dccp_feat_init(struct sock *sk)		int dccp_feat_init(struct sock *sk)
	{		{
	struct dccp_sock *dp = dccp_sk(sk);		struct dccp_sock *dp = dccp_sk(sk);

net/dccp/feat.h

+2 −2

Original line number	Original line	Diff line number	Diff line
	@@ -116,8 +116,8 @@ static inline void dccp_feat_debug(const u8 type, const u8 feat, const u8 val)
	extern int dccp_feat_register_sp(struct sock *sk, u8 feat, u8 is_local,		extern int dccp_feat_register_sp(struct sock *sk, u8 feat, u8 is_local,
	u8 const *list, u8 len);		u8 const *list, u8 len);
	extern int dccp_feat_register_nn(struct sock *sk, u8 feat, u64 val);		extern int dccp_feat_register_nn(struct sock *sk, u8 feat, u64 val);
	extern int dccp_feat_change_recv(struct sock *sk, u8 type, u8 feature,		extern int dccp_feat_parse_options(struct sock , struct dccp_request_sock ,
	u8 *val, u8 len);		u8 mand, u8 opt, u8 feat, u8 *val, u8 len);
	extern int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature,		extern int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature,
	u8 *val, u8 len);		u8 *val, u8 len);
	extern void dccp_feat_clean(struct dccp_minisock *dmsk);		extern void dccp_feat_clean(struct dccp_minisock *dmsk);

net/dccp/options.c

+8 −15

Original line number	Original line	Diff line number	Diff line
	@@ -135,22 +135,13 @@ int dccp_parse_options(struct sock sk, struct dccp_request_sock dreq,
	(unsigned long long)opt_recv->dccpor_ndp);		(unsigned long long)opt_recv->dccpor_ndp);
	break;		break;
	case DCCPO_CHANGE_L:		case DCCPO_CHANGE_L:
	/* fall through */
	case DCCPO_CHANGE_R:		case DCCPO_CHANGE_R:
	if (pkt_type == DCCP_PKT_DATA)		if (pkt_type == DCCP_PKT_DATA)
	break;		break;
	if (len < 2)		rc = dccp_feat_parse_options(sk, dreq, mandatory, opt,
	goto out_invalid_option;		*value, value + 1, len - 1);
	rc = dccp_feat_change_recv(sk, opt, *value, value + 1,		if (rc)
	len - 1);		goto out_featneg_failed;
	/*
	* When there is a change error, change_recv is
	* responsible for dealing with it. i.e. reply with an
	* empty confirm.
	* If the change was mandatory, then we need to die.
	*/
	if (rc && mandatory)
	goto out_invalid_option;
	break;		break;
	case DCCPO_CONFIRM_L:		case DCCPO_CONFIRM_L:
	/* fall through */		/* fall through */
	@@ -292,8 +283,10 @@ out_nonsensical_length:

	out_invalid_option:		out_invalid_option:
	DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT);		DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT);
	DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_OPTION_ERROR;		rc = DCCP_RESET_CODE_OPTION_ERROR;
	DCCP_WARN("DCCP(%p): invalid option %d, len=%d", sk, opt, len);		out_featneg_failed:
			DCCP_WARN("DCCP(%p): Option %d (len=%d) error=%u\n", sk, opt, len, rc);
			DCCP_SKB_CB(skb)->dccpd_reset_code = rc;
	DCCP_SKB_CB(skb)->dccpd_reset_data[0] = opt;		DCCP_SKB_CB(skb)->dccpd_reset_data[0] = opt;
	DCCP_SKB_CB(skb)->dccpd_reset_data[1] = len > 0 ? value[0] : 0;		DCCP_SKB_CB(skb)->dccpd_reset_data[1] = len > 0 ? value[0] : 0;
	DCCP_SKB_CB(skb)->dccpd_reset_data[2] = len > 1 ? value[1] : 0;		DCCP_SKB_CB(skb)->dccpd_reset_data[2] = len > 1 ? value[1] : 0;

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