LXR linux/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
  23struct 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 */
  45struct 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
  88extern struct ccid_operations ccid2_ops;
  89#ifdef CONFIG_IP_DCCP_CCID3
  90extern struct ccid_operations ccid3_ops;
  91#endif
  92
  93int ccid_initialize_builtins(void);
  94void ccid_cleanup_builtins(void);
  95
  96struct ccid {
  97        struct ccid_operations *ccid_ops;
  98        char                   ccid_priv[];
  99};
 100
 101static inline void *ccid_priv(const struct ccid *ccid)
 102{
 103        return (void *)ccid->ccid_priv;
 104}
 105
 106bool ccid_support_check(u8 const *ccid_array, u8 array_len);
 107int ccid_get_builtin_ccids(u8 **ccid_array, u8 *array_len);
 108int ccid_getsockopt_builtin_ccids(struct sock *sk, int len,
 109                                  char __user *, int __user *);
 110
 111struct ccid *ccid_new(const u8 id, struct sock *sk, bool rx);
 112
 113static 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
 122static 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
 131void ccid_hc_rx_delete(struct ccid *ccid, struct sock *sk);
 132void 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
 144enum 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
 152static 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
 163static 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
 171static 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
 178static 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
 185static 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 */
 199static 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 */
 211static 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
 219static 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
 227static 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
 234static 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
 241static 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
 252static 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 */
 263