net/dccp/feat.h

   1 #ifndef _DCCP_FEAT_H
   2 #define _DCCP_FEAT_H
   3 /*
   4  *  net/dccp/feat.h
   5  *
   6  *  An implementation of the DCCP protocol
   7  *  Copyright (c) 2005 Andrea Bittau <a.bittau@cs.ucl.ac.uk>
   8  *
   9  *      This program is free software; you can redistribute it and/or modify it
  10  *      under the terms of the GNU General Public License version 2 as
  11  *      published by the Free Software Foundation.
  12  */
  13
  14 #include <linux/types.h>
  15 #include "dccp.h"
  16
  17 enum dccp_feat_type {
  18         FEAT_AT_RX   = 1,       /* located at RX side of half-connection  */
  19         FEAT_AT_TX   = 2,       /* located at TX side of half-connection  */
  20         FEAT_SP      = 4,       /* server-priority reconciliation (6.3.1) */
  21         FEAT_NN      = 8,       /* non-negotiable reconciliation (6.3.2)  */
  22         FEAT_UNKNOWN = 0xFF     /* not understood or invalid feature      */
  23 };
  24
  25 enum dccp_feat_state {
  26         FEAT_DEFAULT = 0,       /* using default values from 6.4 */
  27         FEAT_INITIALISING,      /* feature is being initialised  */
  28         FEAT_CHANGING,          /* Change sent but not confirmed yet */
  29         FEAT_UNSTABLE,          /* local modification in state CHANGING */
  30         FEAT_STABLE             /* both ends (think they) agree */
  31 };
  32
  33 /**
  34  * dccp_feat_val  -  Container for SP or NN feature values
  35  * @nn:     single NN value
  36  * @sp.vec: single SP value plus optional preference list
  37  * @sp.len: length of @sp.vec in bytes
  38  */
  39 typedef union {
  40         u64 nn;
  41         struct {
  42                 u8      *vec;
  43                 u8      len;
  44         }   sp;
  45 } dccp_feat_val;
  46
  47 /**
  48  * struct feat_entry  -  Data structure to perform feature negotiation
  49  * @feat_num: one of %dccp_feature_numbers
  50  * @val: feature's current value (SP features may have preference list)
  51  * @state: feature's current state
  52  * @needs_mandatory: whether Mandatory options should be sent
  53  * @needs_confirm: whether to send a Confirm instead of a Change
  54  * @empty_confirm: whether to send an empty Confirm (depends on @needs_confirm)
  55  * @is_local: feature location (1) or feature-remote (0)
  56  * @node: list pointers, entries arranged in FIFO order
  57  */
  58 struct dccp_feat_entry {
  59         u8                      feat_num;
  60         dccp_feat_val           val;
  61         enum dccp_feat_state    state:8;
  62         bool                    needs_mandatory:1,
  63                                 needs_confirm:1,
  64                                 empty_confirm:1,
  65                                 is_local:1;
  66
  67         struct list_head        node;
  68 };
  69
  70 static inline u8 dccp_feat_genopt(struct dccp_feat_entry *entry)
  71 {
  72         if (entry->needs_confirm)
  73                 return entry->is_local ? DCCPO_CONFIRM_L : DCCPO_CONFIRM_R;
  74         return entry->is_local ? DCCPO_CHANGE_L : DCCPO_CHANGE_R;
  75 }
  76
  77 #ifdef CONFIG_IP_DCCP_DEBUG
  78 extern const char *dccp_feat_typename(const u8 type);
  79 extern const char *dccp_feat_name(const u8 feat);
  80
  81 static inline void dccp_feat_debug(const u8 type, const u8 feat, const u8 val)
  82 {
  83         dccp_pr_debug("%s(%s (%d), %d)\n", dccp_feat_typename(type),
  84                                            dccp_feat_name(feat), feat, val);
  85 }
  86 #else
  87 #define dccp_feat_debug(type, feat, val)
  88 #endif /* CONFIG_IP_DCCP_DEBUG */
  89
  90 extern int  dccp_feat_change(struct dccp_minisock *dmsk, u8 type, u8 feature,
  91                              u8 *val, u8 len, gfp_t gfp);
  92 extern int  dccp_feat_change_recv(struct sock *sk, u8 type, u8 feature,
  93                                   u8 *val, u8 len);
  94 extern int  dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature,
  95                                    u8 *val, u8 len);
  96 extern void dccp_feat_clean(struct dccp_minisock *dmsk);
  97 extern int  dccp_feat_clone(struct sock *oldsk, struct sock *newsk);
  98 extern int  dccp_feat_init(struct dccp_minisock *dmsk);
  99
 100 #endif /* _DCCP_FEAT_H */