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Commit 61e6473e authored by Gerrit Renker's avatar Gerrit Renker Committed by David S. Miller
Browse files

dccp: List management for new feature negotiation 



This adds list initial fields and list management functions for the
new feature negotiation implementation.

Thanks to Arnaldo for suggestions and improvements.

Signed-off-by: default avatarGerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: default avatarIan McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 7d43d1a0

net/dccp/dccp.h

+2 −0
Original line number Original line Diff line number Diff line
@@ -441,6 +441,8 @@ static inline int dccp_ack_pending(const struct sock *sk) 
	       inet_csk_ack_scheduled(sk);

	       inet_csk_ack_scheduled(sk);

}

}





extern void dccp_feat_list_purge(struct list_head *fn_list);



extern int dccp_insert_options(struct sock *sk, struct sk_buff *skb);

extern int dccp_insert_options(struct sock *sk, struct sk_buff *skb);

extern int dccp_insert_options_rsk(struct dccp_request_sock*, struct sk_buff*);

extern int dccp_insert_options_rsk(struct dccp_request_sock*, struct sk_buff*);

extern int dccp_insert_option_elapsed_time(struct sock *sk,

extern int dccp_insert_option_elapsed_time(struct sock *sk,

net/dccp/feat.c

+73 −0
Original line number Original line Diff line number Diff line
@@ -60,6 +60,79 @@ static const struct { 
};

};

#define DCCP_FEAT_SUPPORTED_MAX		ARRAY_SIZE(dccp_feat_table)

#define DCCP_FEAT_SUPPORTED_MAX		ARRAY_SIZE(dccp_feat_table)





/**

 * dccp_feat_index  -  Hash function to map feature number into array position

 * Returns consecutive array index or -1 if the feature is not understood.

 */

static int dccp_feat_index(u8 feat_num)

{

	/* The first 9 entries are occupied by the types from RFC 4340, 6.4 */

	if (feat_num > DCCPF_RESERVED && feat_num <= DCCPF_DATA_CHECKSUM)

		return feat_num - 1;



	/*

	 * Other features: add cases for new feature types here after adding

	 * them to the above table.

	 */

	switch (feat_num) {

	case DCCPF_SEND_LEV_RATE:

			return DCCP_FEAT_SUPPORTED_MAX - 1;

	}

	return -1;

}



static u8 dccp_feat_type(u8 feat_num)

{

	int idx = dccp_feat_index(feat_num);



	if (idx < 0)

		return FEAT_UNKNOWN;

	return dccp_feat_table[idx].reconciliation;

}



static void dccp_feat_val_destructor(u8 feat_num, dccp_feat_val *val)

{

	if (unlikely(val == NULL))

		return;

	if (dccp_feat_type(feat_num) == FEAT_SP)

		kfree(val->sp.vec);

	memset(val, 0, sizeof(*val));

}



static void dccp_feat_entry_destructor(struct dccp_feat_entry *entry)

{

	if (entry != NULL) {

		dccp_feat_val_destructor(entry->feat_num, &entry->val);

		kfree(entry);

	}

}



/*

 * List management functions

 *

 * Feature negotiation lists rely on and maintain the following invariants:

 * - each feat_num in the list is known, i.e. we know its type and default value

 * - each feat_num/is_local combination is unique (old entries are overwritten)

 * - SP values are always freshly allocated

 * - list is sorted in increasing order of feature number (faster lookup)

 */



static inline void dccp_feat_list_pop(struct dccp_feat_entry *entry)

{

	list_del(&entry->node);

	dccp_feat_entry_destructor(entry);

}



void dccp_feat_list_purge(struct list_head *fn_list)

{

	struct dccp_feat_entry *entry, *next;



	list_for_each_entry_safe(entry, next, fn_list, node)

		dccp_feat_entry_destructor(entry);

	INIT_LIST_HEAD(fn_list);

}

EXPORT_SYMBOL_GPL(dccp_feat_list_purge);



int dccp_feat_change(struct dccp_minisock *dmsk, u8 type, u8 feature,

int dccp_feat_change(struct dccp_minisock *dmsk, u8 type, u8 feature,

		     u8 *val, u8 len, gfp_t gfp)

		     u8 *val, u8 len, gfp_t gfp)

{

{