net/dccp/ccid.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 #ifndef _CCID_H
   3 #define _CCID_H
   4 /*
   5  *  net/dccp/ccid.h
   6  *
   7  *  An implementation of the DCCP protocol
   8  *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>
   9  *
  10  *  CCID infrastructure
  11  */
  12
  13 #include <net/sock.h>
  14 #include <linux/compiler.h>
  15 #include <linux/dccp.h>
  16 #include <linux/list.h>
  17 #include <linux/module.h>
  18
  19 /* maximum value for a CCID (RFC 4340, 19.5) */
  20 #define CCID_MAX                255
  21 #define CCID_SLAB_NAME_LENGTH   32
  22
  23 struct tcp_info;
  24
  25 /**
  26  *  struct ccid_operations  -  Interface to Congestion-Control Infrastructure
  27  *
  28  *  @ccid_id: numerical CCID ID (up to %CCID_MAX, cf. table 5 in RFC 4340, 10.)
  29  *  @ccid_ccmps: the CCMPS including network/transport headers (0 when disabled)
  30  *  @ccid_name: alphabetical identifier string for @ccid_id
  31  *  @ccid_hc_{r,t}x_slab: memory pool for the receiver/sender half-connection
  32  *  @ccid_hc_{r,t}x_obj_size: size of the receiver/sender half-connection socket
  33  *
  34  *  @ccid_hc_{r,t}x_init: CCID-specific initialisation routine (before startup)
  35  *  @ccid_hc_{r,t}x_exit: CCID-specific cleanup routine (before destruction)
  36  *  @ccid_hc_rx_packet_recv: implements the HC-receiver side
  37  *  @ccid_hc_{r,t}x_parse_options: parsing routine for CCID/HC-specific options
  38  *  @ccid_hc_{r,t}x_insert_options: insert routine for CCID/HC-specific options
  39  *  @ccid_hc_tx_packet_recv: implements feedback processing for the HC-sender
  40  *  @ccid_hc_tx_send_packet: implements the sending part of the HC-sender
  41  *  @ccid_hc_tx_packet_sent: does accounting for packets in flight by HC-sender
  42  *  @ccid_hc_{r,t}x_get_info: INET_DIAG information for HC-receiver/sender
  43  *  @ccid_hc_{r,t}x_getsockopt: socket options specific to HC-receiver/sender
  44  */
  45 struct ccid_operations {
  46         unsigned char           ccid_id;
  47         __u32                   ccid_ccmps;
  48         const char              *ccid_name;
  49         struct kmem_cache       *ccid_hc_rx_slab,
  50                                 *ccid_hc_tx_slab;
  51         char                    ccid_hc_rx_slab_name[CCID_SLAB_NAME_LENGTH];
  52         char                    ccid_hc_tx_slab_name[CCID_SLAB_NAME_LENGTH];
  53         __u32                   ccid_hc_rx_obj_size,
  54                                 ccid_hc_tx_obj_size;
  55         /* Interface Routines */
  56         int             (*ccid_hc_rx_init)(struct ccid *ccid, struct sock *sk);
  57         int             (*ccid_hc_tx_init)(struct ccid *ccid, struct sock *sk);
  58         void            (*ccid_hc_rx_exit)(struct sock *sk);
  59         void            (*ccid_hc_tx_exit)(struct sock *sk);
  60         void            (*ccid_hc_rx_packet_recv)(struct sock *sk,
  61                                                   struct sk_buff *skb);
  62         int             (*ccid_hc_rx_parse_options)(struct sock *sk, u8 pkt,
  63                                                     u8 opt, u8 *val, u8 len);
  64         int             (*ccid_hc_rx_insert_options)(struct sock *sk,
  65                                                      struct sk_buff *skb);
  66         void            (*ccid_hc_tx_packet_recv)(struct sock *sk,
  67                                                   struct sk_buff *skb);
  68         int             (*ccid_hc_tx_parse_options)(struct sock *sk, u8 pkt,
  69                                                     u8 opt, u8 *val, u8 len);
  70         int             (*ccid_hc_tx_send_packet)(struct sock *sk,
  71                                                   struct sk_buff *skb);
  72         void            (*ccid_hc_tx_packet_sent)(struct sock *sk,
  73                                                   unsigned int len);
  74         void            (*ccid_hc_rx_get_info)(struct sock *sk,
  75                                                struct tcp_info *info);
  76         void            (*ccid_hc_tx_get_info)(struct sock *sk,
  77                                                struct tcp_info *info);
  78         int             (*ccid_hc_rx_getsockopt)(struct sock *sk,
  79                                                  const int optname, int len,
  80                                                  u32 __user *optval,
  81                                                  int __user *optlen);
  82         int             (*ccid_hc_tx_getsockopt)(struct sock *sk,
  83                                                  const int optname, int len,
  84                                                  u32 __user *optval,
  85                                                  int __user *optlen);
  86 };
  87
  88 extern struct ccid_operations ccid2_ops;
  89 #ifdef CONFIG_IP_DCCP_CCID3
  90 extern struct ccid_operations ccid3_ops;
  91 #endif
  92
  93 int ccid_initialize_builtins(void);
  94 void ccid_cleanup_builtins(void);
  95
  96 struct ccid {
  97         struct ccid_operations *ccid_ops;
  98         char                   ccid_priv[];
  99 };
 100
 101 static inline void *ccid_priv(const struct ccid *ccid)
 102 {
 103         return (void *)ccid->ccid_priv;
 104 }
 105
 106 bool ccid_support_check(u8 const *ccid_array, u8 array_len);
 107 int ccid_get_builtin_ccids(u8 **ccid_array, u8 *array_len);
 108 int ccid_getsockopt_builtin_ccids(struct sock *sk, int len,
 109                                   char __user *, int __user *);
 110
 111 struct ccid *ccid_new(const u8 id, struct sock *sk, bool rx);
 112
 113 static inline int ccid_get_current_rx_ccid(struct dccp_sock *dp)
 114 {
 115         struct ccid *ccid = dp->dccps_hc_rx_ccid;
 116
 117         if (ccid == NULL || ccid->ccid_ops == NULL)
 118                 return -1;
 119         return ccid->ccid_ops->ccid_id;
 120 }
 121
 122 static inline int ccid_get_current_tx_ccid(struct dccp_sock *dp)
 123 {
 124         struct ccid *ccid = dp->dccps_hc_tx_ccid;
 125
 126         if (ccid == NULL || ccid->ccid_ops == NULL)
 127                 return -1;
 128         return ccid->ccid_ops->ccid_id;
 129 }
 130
 131 void ccid_hc_rx_delete(struct ccid *ccid, struct sock *sk);
 132 void ccid_hc_tx_delete(struct ccid *ccid, struct sock *sk);
 133
 134 /*
 135  * Congestion control of queued data packets via CCID decision.
 136  *
 137  * The TX CCID performs its congestion-control by indicating whether and when a
 138  * queued packet may be sent, using the return code of ccid_hc_tx_send_packet().
 139  * The following modes are supported via the symbolic constants below:
 140  * - timer-based pacing    (CCID returns a delay value in milliseconds);
 141  * - autonomous dequeueing (CCID internally schedules dccps_xmitlet).
 142  */
 143
 144 enum ccid_dequeueing_decision {
 145         CCID_PACKET_SEND_AT_ONCE =       0x00000,  /* "green light": no delay */
 146         CCID_PACKET_DELAY_MAX =          0x0FFFF,  /* maximum delay in msecs  */
 147         CCID_PACKET_DELAY =              0x10000,  /* CCID msec-delay mode */
 148         CCID_PACKET_WILL_DEQUEUE_LATER = 0x20000,  /* CCID autonomous mode */
 149         CCID_PACKET_ERR =                0xF0000,  /* error condition */
 150 };
 151
 152 static inline int ccid_packet_dequeue_eval(const int return_code)
 153 {
 154         if (return_code < 0)
 155                 return CCID_PACKET_ERR;
 156         if (return_code == 0)
 157                 return CCID_PACKET_SEND_AT_ONCE;
 158         if (return_code <= CCID_PACKET_DELAY_MAX)
 159                 return CCID_PACKET_DELAY;
 160         return return_code;
 161 }
 162
 163 static inline int ccid_hc_tx_send_packet(struct ccid *ccid, struct sock *sk,
 164                                          struct sk_buff *skb)
 165 {
 166         if (ccid->ccid_ops->ccid_hc_tx_send_packet != NULL)
 167                 return ccid->ccid_ops->ccid_hc_tx_send_packet(sk, skb);
 168         return CCID_PACKET_SEND_AT_ONCE;
 169 }
 170
 171 static inline void ccid_hc_tx_packet_sent(struct ccid *ccid, struct sock *sk,
 172                                           unsigned int len)
 173 {
 174         if (ccid->ccid_ops->ccid_hc_tx_packet_sent != NULL)
 175                 ccid->ccid_ops->ccid_hc_tx_packet_sent(sk, len);
 176 }
 177
 178 static inline void ccid_hc_rx_packet_recv(struct ccid *ccid, struct sock *sk,
 179                                           struct sk_buff *skb)
 180 {
 181         if (ccid->ccid_ops->ccid_hc_rx_packet_recv != NULL)
 182                 ccid->ccid_ops->ccid_hc_rx_packet_recv(sk, skb);
 183 }
 184
 185 static inline void ccid_hc_tx_packet_recv(struct ccid *ccid, struct sock *sk,
 186                                           struct sk_buff *skb)
 187 {
 188         if (ccid->ccid_ops->ccid_hc_tx_packet_recv != NULL)
 189                 ccid->ccid_ops->ccid_hc_tx_packet_recv(sk, skb);
 190 }
 191
 192 /**
 193  * ccid_hc_tx_parse_options  -  Parse CCID-specific options sent by the receiver
 194  * @pkt: type of packet that @opt appears on (RFC 4340, 5.1)
 195  * @opt: the CCID-specific option type (RFC 4340, 5.8 and 10.3)
 196  * @val: value of @opt
 197  * @len: length of @val in bytes
 198  */
 199 static inline int ccid_hc_tx_parse_options(struct ccid *ccid, struct sock *sk,
 200                                            u8 pkt, u8 opt, u8 *val, u8 len)
 201 {
 202         if (!ccid || !ccid->ccid_ops->ccid_hc_tx_parse_options)
 203                 return 0;
 204         return ccid->ccid_ops->ccid_hc_tx_parse_options(sk, pkt, opt, val, len);
 205 }
 206
 207 /**
 208  * ccid_hc_rx_parse_options  -  Parse CCID-specific options sent by the sender
 209  * Arguments are analogous to ccid_hc_tx_parse_options()
 210  */
 211 static inline int ccid_hc_rx_parse_options(struct ccid *ccid, struct sock *sk,
 212                                            u8 pkt, u8 opt, u8 *val, u8 len)
 213 {
 214         if (!ccid || !ccid->ccid_ops->ccid_hc_rx_parse_options)
 215                 return 0;
 216         return ccid->ccid_ops->ccid_hc_rx_parse_options(sk, pkt, opt, val, len);
 217 }
 218
 219 static inline int ccid_hc_rx_insert_options(struct ccid *ccid, struct sock *sk,
 220                                             struct sk_buff *skb)
 221 {
 222         if (ccid->ccid_ops->ccid_hc_rx_insert_options != NULL)
 223                 return ccid->ccid_ops->ccid_hc_rx_insert_options(sk, skb);
 224         return 0;
 225 }
 226
 227 static inline void ccid_hc_rx_get_info(struct ccid *ccid, struct sock *sk,
 228                                        struct tcp_info *info)
 229 {
 230         if (ccid->ccid_ops->ccid_hc_rx_get_info != NULL)
 231                 ccid->ccid_ops->ccid_hc_rx_get_info(sk, info);
 232 }
 233
 234 static inline void ccid_hc_tx_get_info(struct ccid *ccid, struct sock *sk,
 235                                        struct tcp_info *info)
 236 {
 237         if (ccid->ccid_ops->ccid_hc_tx_get_info != NULL)
 238                 ccid->ccid_ops->ccid_hc_tx_get_info(sk, info);
 239 }
 240
 241 static inline int ccid_hc_rx_getsockopt(struct ccid *ccid, struct sock *sk,
 242                                         const int optname, int len,
 243                                         u32 __user *optval, int __user *optlen)
 244 {
 245         int rc = -ENOPROTOOPT;
 246         if (ccid != NULL && ccid->ccid_ops->ccid_hc_rx_getsockopt != NULL)
 247                 rc = ccid->ccid_ops->ccid_hc_rx_getsockopt(sk, optname, len,
 248                                                  optval, optlen);
 249         return rc;
 250 }
 251
 252 static inline int ccid_hc_tx_getsockopt(struct ccid *ccid, struct sock *sk,
 253                                         const int optname, int len,
 254                                         u32 __user *optval, int __user *optlen)
 255 {
 256         int rc = -ENOPROTOOPT;
 257         if (ccid != NULL && ccid->ccid_ops->ccid_hc_tx_getsockopt != NULL)
 258                 rc = ccid->ccid_ops->ccid_hc_tx_getsockopt(sk, optname, len,
 259                                                  optval, optlen);
 260         return rc;
 261 }
 262 #endif /* _CCID_H */