dccp: Header option insertion routine for feature-negotiation (8c862c23) · Commits · 戴 / test

net/dccp/feat.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -141,4 +141,6 @@ extern void dccp_encode_value_var(const u64 value, u8 *to, const u8 len);
		extern u64 dccp_decode_value_var(const u8 *bf, const u8 len);

		extern int dccp_insert_option_mandatory(struct sk_buff *skb);
		extern int dccp_insert_fn_opt(struct sk_buff *skb, u8 type, u8 feat,
		u8 *val, u8 len, bool repeat_first);
		#endif /* _DCCP_FEAT_H */

net/dccp/options.c

+31 −60

Original line number	Diff line number	Diff line
		@@ -482,23 +482,46 @@ int dccp_insert_option_mandatory(struct sk_buff *skb)
		return 0;
		}

		static int dccp_insert_feat_opt(struct sk_buff *skb, u8 type, u8 feat,
		u8 *val, u8 len)
		/**
		* dccp_insert_fn_opt - Insert single Feature-Negotiation option into @skb
		* @type: %DCCPO_CHANGE_L, %DCCPO_CHANGE_R, %DCCPO_CONFIRM_L, %DCCPO_CONFIRM_R
		* @feat: one out of %dccp_feature_numbers
		* @val: NN value or SP array (preferred element first) to copy
		* @len: true length of @val in bytes (excluding first element repetition)
		* @repeat_first: whether to copy the first element of @val twice
		* The last argument is used to construct Confirm options, where the preferred
		* value and the preference list appear separately (RFC 4340, 6.3.1). Preference
		* lists are kept such that the preferred entry is always first, so we only need
		* to copy twice, and avoid the overhead of cloning into a bigger array.
		*/
		int dccp_insert_fn_opt(struct sk_buff *skb, u8 type, u8 feat,
		u8 *val, u8 len, bool repeat_first)
		{
		u8 *to;
		u8 tot_len, *to;

		if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 3 > DCCP_MAX_OPT_LEN) {
		DCCP_WARN("packet too small for feature %d option!\n", feat);
		/* take the `Feature' field and possible repetition into account */
		if (len > (DCCP_SINGLE_OPT_MAXLEN - 2)) {
		DCCP_WARN("length %u for feature %u too large\n", len, feat);
		return -1;
		}

		DCCP_SKB_CB(skb)->dccpd_opt_len += len + 3;
		if (unlikely(val == NULL \|\| len == 0))
		len = repeat_first = 0;
		tot_len = 3 + repeat_first + len;

		if (DCCP_SKB_CB(skb)->dccpd_opt_len + tot_len > DCCP_MAX_OPT_LEN) {
		DCCP_WARN("packet too small for feature %d option!\n", feat);
		return -1;
		}
		DCCP_SKB_CB(skb)->dccpd_opt_len += tot_len;

		to = skb_push(skb, len + 3);
		to = skb_push(skb, tot_len);
		*to++ = type;
		*to++ = len + 3;
		*to++ = tot_len;
		*to++ = feat;

		if (repeat_first)
		to++ = val;
		if (len)
		memcpy(to, val, len);

		@@ -508,51 +531,6 @@ static int dccp_insert_feat_opt(struct sk_buff *skb, u8 type, u8 feat,
		return 0;
		}

		static int dccp_insert_options_feat(struct sock sk, struct sk_buff skb)
		{
		struct dccp_minisock *dmsk = dccp_msk(sk);
		struct dccp_opt_pend opt, next;
		int change = 0;

		/* confirm any options [NN opts] */
		list_for_each_entry_safe(opt, next, &dmsk->dccpms_conf, dccpop_node) {
		dccp_insert_feat_opt(skb, opt->dccpop_type,
		opt->dccpop_feat, opt->dccpop_val,
		opt->dccpop_len);
		/* fear empty confirms */
		if (opt->dccpop_val)
		kfree(opt->dccpop_val);
		kfree(opt);
		}
		INIT_LIST_HEAD(&dmsk->dccpms_conf);

		/* see which features we need to send */
		list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
		/* see if we need to send any confirm */
		if (opt->dccpop_sc) {
		dccp_insert_feat_opt(skb, opt->dccpop_type + 1,
		opt->dccpop_feat,
		opt->dccpop_sc->dccpoc_val,
		opt->dccpop_sc->dccpoc_len);

		BUG_ON(!opt->dccpop_sc->dccpoc_val);
		kfree(opt->dccpop_sc->dccpoc_val);
		kfree(opt->dccpop_sc);
		opt->dccpop_sc = NULL;
		}

		/* any option not confirmed, re-send it */
		if (!opt->dccpop_conf) {
		dccp_insert_feat_opt(skb, opt->dccpop_type,
		opt->dccpop_feat, opt->dccpop_val,
		opt->dccpop_len);
		change++;
		}
		}

		return 0;
		}

		/* The length of all options needs to be a multiple of 4 (5.8) */
		static void dccp_insert_option_padding(struct sk_buff *skb)
		{
		@@ -589,13 +567,6 @@ int dccp_insert_options(struct sock sk, struct sk_buff skb)
		dp->dccps_hc_rx_insert_options = 0;
		}

		/* Feature negotiation */
		/* Data packets can't do feat negotiation */
		if (DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATA &&
		DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATAACK &&
		dccp_insert_options_feat(sk, skb))
		return -1;

		/*
		* Obtain RTT sample from Request/Response exchange.
		* This is currently used in CCID 3 initialisation.

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