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>
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@ -441,6 +441,8 @@ static inline int dccp_ack_pending(const struct sock *sk)
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inet_csk_ack_scheduled(sk);
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}
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extern void dccp_feat_list_purge(struct list_head *fn_list);
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extern int dccp_insert_options(struct sock *sk, struct sk_buff *skb);
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extern int dccp_insert_options_rsk(struct dccp_request_sock*, struct sk_buff*);
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extern int dccp_insert_option_elapsed_time(struct sock *sk,
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@ -60,6 +60,79 @@ static const struct {
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};
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#define DCCP_FEAT_SUPPORTED_MAX ARRAY_SIZE(dccp_feat_table)
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/**
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* dccp_feat_index - Hash function to map feature number into array position
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* Returns consecutive array index or -1 if the feature is not understood.
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*/
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static int dccp_feat_index(u8 feat_num)
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{
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/* The first 9 entries are occupied by the types from RFC 4340, 6.4 */
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if (feat_num > DCCPF_RESERVED && feat_num <= DCCPF_DATA_CHECKSUM)
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return feat_num - 1;
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/*
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* Other features: add cases for new feature types here after adding
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* them to the above table.
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*/
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switch (feat_num) {
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case DCCPF_SEND_LEV_RATE:
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return DCCP_FEAT_SUPPORTED_MAX - 1;
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}
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return -1;
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}
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static u8 dccp_feat_type(u8 feat_num)
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{
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int idx = dccp_feat_index(feat_num);
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if (idx < 0)
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return FEAT_UNKNOWN;
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return dccp_feat_table[idx].reconciliation;
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}
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static void dccp_feat_val_destructor(u8 feat_num, dccp_feat_val *val)
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{
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if (unlikely(val == NULL))
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return;
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if (dccp_feat_type(feat_num) == FEAT_SP)
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kfree(val->sp.vec);
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memset(val, 0, sizeof(*val));
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}
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static void dccp_feat_entry_destructor(struct dccp_feat_entry *entry)
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{
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if (entry != NULL) {
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dccp_feat_val_destructor(entry->feat_num, &entry->val);
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kfree(entry);
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}
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}
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/*
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* List management functions
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*
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* Feature negotiation lists rely on and maintain the following invariants:
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* - each feat_num in the list is known, i.e. we know its type and default value
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* - each feat_num/is_local combination is unique (old entries are overwritten)
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* - SP values are always freshly allocated
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* - list is sorted in increasing order of feature number (faster lookup)
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*/
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static inline void dccp_feat_list_pop(struct dccp_feat_entry *entry)
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{
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list_del(&entry->node);
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dccp_feat_entry_destructor(entry);
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}
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void dccp_feat_list_purge(struct list_head *fn_list)
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{
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struct dccp_feat_entry *entry, *next;
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list_for_each_entry_safe(entry, next, fn_list, node)
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dccp_feat_entry_destructor(entry);
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INIT_LIST_HEAD(fn_list);
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}
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EXPORT_SYMBOL_GPL(dccp_feat_list_purge);
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int dccp_feat_change(struct dccp_minisock *dmsk, u8 type, u8 feature,
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u8 *val, u8 len, gfp_t gfp)
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{
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