net/dccp/ccid.h

   1 #ifndef _CCID_H
   2 #define _CCID_H
   3 /*
   4  *  net/dccp/ccid.h
   5  *
   6  *  An implementation of the DCCP protocol
   7  *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>
   8  *
   9  *  CCID infrastructure
  10  *
  11  *      This program is free software; you can redistribute it and/or modify it
  12  *      under the terms of the GNU General Public License version 2 as
  13  *      published by the Free Software Foundation.
  14  */
  15
  16 #include <net/sock.h>
  17 #include <linux/compiler.h>
  18 #include <linux/dccp.h>
  19 #include <linux/list.h>
  20 #include <linux/module.h>
  21
  22 /* maximum value for a CCID (RFC 4340, 19.5) */
  23 #define CCID_MAX                255
  24 #define CCID_SLAB_NAME_LENGTH   32
  25
  26 struct tcp_info;
  27
  28 /**
  29  *  struct ccid_operations  -  Interface to Congestion-Control Infrastructure
  30  *
  31  *  @ccid_id: numerical CCID ID (up to %CCID_MAX, cf. table 5 in RFC 4340, 10.)
  32  *  @ccid_ccmps: the CCMPS including network/transport headers (0 when disabled)
  33  *  @ccid_name: alphabetical identifier string for @ccid_id
  34  *  @ccid_hc_{r,t}x_slab: memory pool for the receiver/sender half-connection
  35  *  @ccid_hc_{r,t}x_obj_size: size of the receiver/sender half-connection socket
  36  *
  37  *  @ccid_hc_{r,t}x_init: CCID-specific initialisation routine (before startup)
  38  *  @ccid_hc_{r,t}x_exit: CCID-specific cleanup routine (before destruction)
  39  *  @ccid_hc_rx_packet_recv: implements the HC-receiver side
  40  *  @ccid_hc_{r,t}x_parse_options: parsing routine for CCID/HC-specific options
  41  *  @ccid_hc_{r,t}x_insert_options: insert routine for CCID/HC-specific options
  42  *  @ccid_hc_tx_packet_recv: implements feedback processing for the HC-sender
  43  *  @ccid_hc_tx_send_packet: implements the sending part of the HC-sender
  44  *  @ccid_hc_tx_packet_sent: does accounting for packets in flight by HC-sender
  45  *  @ccid_hc_{r,t}x_get_info: INET_DIAG information for HC-receiver/sender
  46  *  @ccid_hc_{r,t}x_getsockopt: socket options specific to HC-receiver/sender
  47  */
  48 struct ccid_operations {
  49         unsigned char           ccid_id;
  50         __u32                   ccid_ccmps;
  51         const char              *ccid_name;
  52         struct kmem_cache       *ccid_hc_rx_slab,
  53                                 *ccid_hc_tx_slab;
  54         char                    ccid_hc_rx_slab_name[CCID_SLAB_NAME_LENGTH];
  55         char                    ccid_hc_tx_slab_name[CCID_SLAB_NAME_LENGTH];
  56         __u32                   ccid_hc_rx_obj_size,
  57                                 ccid_hc_tx_obj_size;
  58         /* Interface Routines */
  59         int             (*ccid_hc_rx_init)(struct ccid *ccid, struct sock *sk);
  60         int             (*ccid_hc_tx_init)(struct ccid *ccid, struct sock *sk);
  61         void            (*ccid_hc_rx_exit)(struct sock *sk);
  62         void            (*ccid_hc_tx_exit)(struct sock *sk);
  63         void            (*ccid_hc_rx_packet_recv)(struct sock *sk,
  64                                                   struct sk_buff *skb);
  65         int             (*ccid_hc_rx_parse_options)(struct sock *sk, u8 pkt,
  66                                                     u8 opt, u8 *val, u8 len);
  67         int             (*ccid_hc_rx_insert_options)(struct sock *sk,
  68                                                      struct sk_buff *skb);
  69         void            (*ccid_hc_tx_packet_recv)(struct sock *sk,
  70                                                   struct sk_buff *skb);
  71         int             (*ccid_hc_tx_parse_options)(struct sock *sk, u8 pkt,
  72                                                     u8 opt, u8 *val, u8 len);
  73         int             (*ccid_hc_tx_send_packet)(struct sock *sk,
  74                                                   struct sk_buff *skb);
  75         void            (*ccid_hc_tx_packet_sent)(struct sock *sk,
  76                                                   unsigned int len);
  77         void            (*ccid_hc_rx_get_info)(struct sock *sk,
  78                                                struct tcp_info *info);
  79         void            (*ccid_hc_tx_get_info)(struct sock *sk,
  80                                                struct tcp_info *info);
  81         int             (*ccid_hc_rx_getsockopt)(struct sock *sk,
  82                                                  const int optname, int len,
  83                                                  u32 __user *optval,
  84                                                  int __user *optlen);
  85         int             (*ccid_hc_tx_getsockopt)(struct sock *sk,
  86                                                  const int optname, int len,
  87                                                  u32 __user *optval,
  88                                                  int __user *optlen);
  89 };
  90
  91 extern struct ccid_operations ccid2_ops;
  92 #ifdef CONFIG_IP_DCCP_CCID3
  93 extern struct ccid_operations ccid3_ops;
  94 #endif
  95
  96 int ccid_initialize_builtins(void);
  97 void ccid_cleanup_builtins(void);
  98
  99 struct ccid {
 100         struct ccid_operations *ccid_ops;
 101         char                   ccid_priv[0];
 102 };
 103
 104 static inline void *ccid_priv(const struct ccid *ccid)
 105 {
 106         return (void *)ccid->ccid_priv;
 107 }
 108
 109 bool ccid_support_check(u8 const *ccid_array, u8 array_len);
 110 int ccid_get_builtin_ccids(u8 **ccid_array, u8 *array_len);
 111 int ccid_getsockopt_builtin_ccids(struct sock *sk, int len,
 112                                   char __user *, int __user *);
 113
 114 struct ccid *ccid_new(const u8 id, struct sock *sk, bool rx);
 115
 116 static inline int ccid_get_current_rx_ccid(struct dccp_sock *dp)
 117 {
 118         struct ccid *ccid = dp->dccps_hc_rx_ccid;
 119
 120         if (ccid == NULL || ccid->ccid_ops == NULL)
 121                 return -1;
 122         return ccid->ccid_ops->ccid_id;
 123 }
 124
 125 static inline int ccid_get_current_tx_ccid(struct dccp_sock *dp)
 126 {
 127         struct ccid *ccid = dp->dccps_hc_tx_ccid;
 128
 129         if (ccid == NULL || ccid->ccid_ops == NULL)
 130                 return -1;
 131         return ccid->ccid_ops->ccid_id;
 132 }
 133
 134 void ccid_hc_rx_delete(struct ccid *ccid, struct sock *sk);
 135 void ccid_hc_tx_delete(struct ccid *ccid, struct sock *sk);
 136
 137 /*
 138  * Congestion control of queued data packets via CCID decision.
 139  *
 140  * The TX CCID performs its congestion-control by indicating whether and when a
 141  * queued packet may be sent, using the return code of ccid_hc_tx_send_packet().
 142  * The following modes are supported via the symbolic constants below:
 143  * - timer-based pacing    (CCID returns a delay value in milliseconds);
 144  * - autonomous dequeueing (CCID internally schedules dccps_xmitlet).
 145  */
 146
 147 enum ccid_dequeueing_decision {
 148         CCID_PACKET_SEND_AT_ONCE =       0x00000,  /* "green light": no delay */
 149         CCID_PACKET_DELAY_MAX =          0x0FFFF,  /* maximum delay in msecs  */
 150         CCID_PACKET_DELAY =              0x10000,  /* CCID msec-delay mode */
 151         CCID_PACKET_WILL_DEQUEUE_LATER = 0x20000,  /* CCID autonomous mode */
 152         CCID_PACKET_ERR =                0xF0000,  /* error condition */
 153 };
 154
 155 static inline int ccid_packet_dequeue_eval(const int return_code)
 156 {
 157         if (return_code < 0)
 158                 return CCID_PACKET_ERR;
 159         if (return_code == 0)
 160                 return CCID_PACKET_SEND_AT_ONCE;
 161         if (return_code <= CCID_PACKET_DELAY_MAX)
 162                 return CCID_PACKET_DELAY;
 163         return return_code;
 164 }
 165
 166 static inline int ccid_hc_tx_send_packet(struct ccid *ccid, struct sock *sk,
 167                                          struct sk_buff *skb)
 168 {
 169         if (ccid->ccid_ops->ccid_hc_tx_send_packet != NULL)
 170                 return ccid->ccid_ops->ccid_hc_tx_send_packet(sk, skb);
 171         return CCID_PACKET_SEND_AT_ONCE;
 172 }
 173
 174 static inline void ccid_hc_tx_packet_sent(struct ccid *ccid, struct sock *sk,
 175                                           unsigned int len)
 176 {
 177         if (ccid->ccid_ops->ccid_hc_tx_packet_sent != NULL)
 178                 ccid->ccid_ops->ccid_hc_tx_packet_sent(sk, len);
 179 }
 180
 181 static inline void ccid_hc_rx_packet_recv(struct ccid *ccid, struct sock *sk,
 182                                           struct sk_buff *skb)
 183 {
 184         if (ccid->ccid_ops->ccid_hc_rx_packet_recv != NULL)
 185                 ccid->ccid_ops->ccid_hc_rx_packet_recv(sk, skb);
 186 }
 187
 188 static inline void ccid_hc_tx_packet_recv(struct ccid *ccid, struct sock *sk,
 189                                           struct sk_buff *skb)
 190 {
 191         if (ccid->ccid_ops->ccid_hc_tx_packet_recv != NULL)
 192                 ccid->ccid_ops->ccid_hc_tx_packet_recv(sk, skb);
 193 }
 194
 195 /**
 196  * ccid_hc_tx_parse_options  -  Parse CCID-specific options sent by the receiver
 197  * @pkt: type of packet that @opt appears on (RFC 4340, 5.1)
 198  * @opt: the CCID-specific option type (RFC 4340, 5.8 and 10.3)
 199  * @val: value of @opt
 200  * @len: length of @val in bytes
 201  */
 202 static inline int ccid_hc_tx_parse_options(struct ccid *ccid, struct sock *sk,
 203                                            u8 pkt, u8 opt, u8 *val, u8 len)
 204 {
 205         if (!ccid || !ccid->ccid_ops->ccid_hc_tx_parse_options)
 206                 return 0;
 207         return ccid->ccid_ops->ccid_hc_tx_parse_options(sk, pkt, opt, val, len);
 208 }
 209
 210 /**
 211  * ccid_hc_rx_parse_options  -  Parse CCID-specific options sent by the sender
 212  * Arguments are analogous to ccid_hc_tx_parse_options()
 213  */
 214 static inline int ccid_hc_rx_parse_options(struct ccid *ccid, struct sock *sk,
 215                                            u8 pkt, u8 opt, u8 *val, u8 len)
 216 {
 217         if (!ccid || !ccid->ccid_ops->ccid_hc_rx_parse_options)
 218                 return 0;
 219         return ccid->ccid_ops->ccid_hc_rx_parse_options(sk, pkt, opt, val, len);
 220 }
 221
 222 static inline int ccid_hc_rx_insert_options(struct ccid *ccid, struct sock *sk,
 223                                             struct sk_buff *skb)
 224 {
 225         if (ccid->ccid_ops->ccid_hc_rx_insert_options != NULL)
 226                 return ccid->ccid_ops->ccid_hc_rx_insert_options(sk, skb);
 227         return 0;
 228 }
 229
 230 static inline void ccid_hc_rx_get_info(struct ccid *ccid, struct sock *sk,
 231                                        struct tcp_info *info)
 232 {
 233         if (ccid->ccid_ops->ccid_hc_rx_get_info != NULL)
 234                 ccid->ccid_ops->ccid_hc_rx_get_info(sk, info);
 235 }
 236
 237 static inline void ccid_hc_tx_get_info(struct ccid *ccid, struct sock *sk,
 238                                        struct tcp_info *info)
 239 {
 240         if (ccid->ccid_ops->ccid_hc_tx_get_info != NULL)
 241                 ccid->ccid_ops->ccid_hc_tx_get_info(sk, info);
 242 }
 243
 244 static inline int ccid_hc_rx_getsockopt(struct ccid *ccid, struct sock *sk,
 245                                         const int optname, int len,
 246                                         u32 __user *optval, int __user *optlen)
 247 {
 248         int rc = -ENOPROTOOPT;
 249         if (ccid != NULL && ccid->ccid_ops->ccid_hc_rx_getsockopt != NULL)
 250                 rc = ccid->ccid_ops->ccid_hc_rx_getsockopt(sk, optname, len,
 251                                                  optval, optlen);
 252         return rc;
 253 }
 254
 255 static inline int ccid_hc_tx_getsockopt(struct ccid *ccid, struct sock *sk,
 256                                         const int optname, int len,
 257                                         u32 __user *optval, int __user *optlen)
 258 {
 259         int rc = -ENOPROTOOPT;
 260         if (ccid != NULL && ccid->ccid_ops->ccid_hc_tx_getsockopt != NULL)
 261                 rc = ccid->ccid_ops->ccid_hc_tx_getsockopt(sk, optname, len,
 262                                                  optval, optlen);
 263         return rc;
 264 }
 265 #endif /* _CCID_H */