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: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Gerrit Renker 2008-11-04 23:54:04 -08:00 committed by David S. Miller
parent 7d43d1a0f2
commit 61e6473efb
2 changed files with 75 additions and 0 deletions

View file

@ -441,6 +441,8 @@ static inline int dccp_ack_pending(const struct sock *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_rsk(struct dccp_request_sock*, struct sk_buff*);
extern int dccp_insert_option_elapsed_time(struct sock *sk,

View file

@ -60,6 +60,79 @@ static const struct {
};
#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,
u8 *val, u8 len, gfp_t gfp)
{