include/linux/dccp.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _LINUX_DCCP_H
   3 #define _LINUX_DCCP_H
   4
   5
   6 #include <linux/in.h>
   7 #include <linux/interrupt.h>
   8 #include <linux/ktime.h>
   9 #include <linux/list.h>
  10 #include <linux/uio.h>
  11 #include <linux/workqueue.h>
  12
  13 #include <net/inet_connection_sock.h>
  14 #include <net/inet_sock.h>
  15 #include <net/inet_timewait_sock.h>
  16 #include <net/tcp_states.h>
  17 #include <uapi/linux/dccp.h>
  18
  19 enum dccp_state {
  20         DCCP_OPEN            = TCP_ESTABLISHED,
  21         DCCP_REQUESTING      = TCP_SYN_SENT,
  22         DCCP_LISTEN          = TCP_LISTEN,
  23         DCCP_RESPOND         = TCP_SYN_RECV,
  24         /*
  25          * States involved in closing a DCCP connection:
  26          * 1) ACTIVE_CLOSEREQ is entered by a server sending a CloseReq.
  27          *
  28          * 2) CLOSING can have three different meanings (RFC 4340, 8.3):
  29          *  a. Client has performed active-close, has sent a Close to the server
  30          *     from state OPEN or PARTOPEN, and is waiting for the final Reset
  31          *     (in this case, SOCK_DONE == 1).
  32          *  b. Client is asked to perform passive-close, by receiving a CloseReq
  33          *     in (PART)OPEN state. It sends a Close and waits for final Reset
  34          *     (in this case, SOCK_DONE == 0).
  35          *  c. Server performs an active-close as in (a), keeps TIMEWAIT state.
  36          *
  37          * 3) The following intermediate states are employed to give passively
  38          *    closing nodes a chance to process their unread data:
  39          *    - PASSIVE_CLOSE    (from OPEN => CLOSED) and
  40          *    - PASSIVE_CLOSEREQ (from (PART)OPEN to CLOSING; case (b) above).
  41          */
  42         DCCP_ACTIVE_CLOSEREQ = TCP_FIN_WAIT1,
  43         DCCP_PASSIVE_CLOSE   = TCP_CLOSE_WAIT,  /* any node receiving a Close */
  44         DCCP_CLOSING         = TCP_CLOSING,
  45         DCCP_TIME_WAIT       = TCP_TIME_WAIT,
  46         DCCP_CLOSED          = TCP_CLOSE,
  47         DCCP_NEW_SYN_RECV    = TCP_NEW_SYN_RECV,
  48         DCCP_PARTOPEN        = TCP_MAX_STATES,
  49         DCCP_PASSIVE_CLOSEREQ,                  /* clients receiving CloseReq */
  50         DCCP_MAX_STATES
  51 };
  52
  53 enum {
  54         DCCPF_OPEN            = TCPF_ESTABLISHED,
  55         DCCPF_REQUESTING      = TCPF_SYN_SENT,
  56         DCCPF_LISTEN          = TCPF_LISTEN,
  57         DCCPF_RESPOND         = TCPF_SYN_RECV,
  58         DCCPF_ACTIVE_CLOSEREQ = TCPF_FIN_WAIT1,
  59         DCCPF_CLOSING         = TCPF_CLOSING,
  60         DCCPF_TIME_WAIT       = TCPF_TIME_WAIT,
  61         DCCPF_CLOSED          = TCPF_CLOSE,
  62         DCCPF_NEW_SYN_RECV    = TCPF_NEW_SYN_RECV,
  63         DCCPF_PARTOPEN        = (1 << DCCP_PARTOPEN),
  64 };
  65
  66 static inline struct dccp_hdr *dccp_hdr(const struct sk_buff *skb)
  67 {
  68         return (struct dccp_hdr *)skb_transport_header(skb);
  69 }
  70
  71 static inline struct dccp_hdr *dccp_zeroed_hdr(struct sk_buff *skb, int headlen)
  72 {
  73         skb_push(skb, headlen);
  74         skb_reset_transport_header(skb);
  75         return memset(skb_transport_header(skb), 0, headlen);
  76 }
  77
  78 static inline struct dccp_hdr_ext *dccp_hdrx(const struct dccp_hdr *dh)
  79 {
  80         return (struct dccp_hdr_ext *)((unsigned char *)dh + sizeof(*dh));
  81 }
  82
  83 static inline unsigned int __dccp_basic_hdr_len(const struct dccp_hdr *dh)
  84 {
  85         return sizeof(*dh) + (dh->dccph_x ? sizeof(struct dccp_hdr_ext) : 0);
  86 }
  87
  88 static inline unsigned int dccp_basic_hdr_len(const struct sk_buff *skb)
  89 {
  90         const struct dccp_hdr *dh = dccp_hdr(skb);
  91         return __dccp_basic_hdr_len(dh);
  92 }
  93
  94 static inline __u64 dccp_hdr_seq(const struct dccp_hdr *dh)
  95 {
  96         __u64 seq_nr =  ntohs(dh->dccph_seq);
  97
  98         if (dh->dccph_x != 0)
  99                 seq_nr = (seq_nr << 32) + ntohl(dccp_hdrx(dh)->dccph_seq_low);
 100         else
 101                 seq_nr += (u32)dh->dccph_seq2 << 16;
 102
 103         return seq_nr;
 104 }
 105
 106 static inline struct dccp_hdr_request *dccp_hdr_request(struct sk_buff *skb)
 107 {
 108         return (struct dccp_hdr_request *)(skb_transport_header(skb) +
 109                                            dccp_basic_hdr_len(skb));
 110 }
 111
 112 static inline struct dccp_hdr_ack_bits *dccp_hdr_ack_bits(const struct sk_buff *skb)
 113 {
 114         return (struct dccp_hdr_ack_bits *)(skb_transport_header(skb) +
 115                                             dccp_basic_hdr_len(skb));
 116 }
 117
 118 static inline u64 dccp_hdr_ack_seq(const struct sk_buff *skb)
 119 {
 120         const struct dccp_hdr_ack_bits *dhack = dccp_hdr_ack_bits(skb);
 121         return ((u64)ntohs(dhack->dccph_ack_nr_high) << 32) + ntohl(dhack->dccph_ack_nr_low);
 122 }
 123
 124 static inline struct dccp_hdr_response *dccp_hdr_response(struct sk_buff *skb)
 125 {
 126         return (struct dccp_hdr_response *)(skb_transport_header(skb) +
 127                                             dccp_basic_hdr_len(skb));
 128 }
 129
 130 static inline struct dccp_hdr_reset *dccp_hdr_reset(struct sk_buff *skb)
 131 {
 132         return (struct dccp_hdr_reset *)(skb_transport_header(skb) +
 133                                          dccp_basic_hdr_len(skb));
 134 }
 135
 136 static inline unsigned int __dccp_hdr_len(const struct dccp_hdr *dh)
 137 {
 138         return __dccp_basic_hdr_len(dh) +
 139                dccp_packet_hdr_len(dh->dccph_type);
 140 }
 141
 142 static inline unsigned int dccp_hdr_len(const struct sk_buff *skb)
 143 {
 144         return __dccp_hdr_len(dccp_hdr(skb));
 145 }
 146
 147 /**
 148  * struct dccp_request_sock  -  represent DCCP-specific connection request
 149  * @dreq_inet_rsk: structure inherited from
 150  * @dreq_iss: initial sequence number, sent on the first Response (RFC 4340, 7.1)
 151  * @dreq_gss: greatest sequence number sent (for retransmitted Responses)
 152  * @dreq_isr: initial sequence number received in the first Request
 153  * @dreq_gsr: greatest sequence number received (for retransmitted Request(s))
 154  * @dreq_service: service code present on the Request (there is just one)
 155  * @dreq_featneg: feature negotiation options for this connection
 156  * The following two fields are analogous to the ones in dccp_sock:
 157  * @dreq_timestamp_echo: last received timestamp to echo (13.1)
 158  * @dreq_timestamp_echo: the time of receiving the last @dreq_timestamp_echo
 159  */
 160 struct dccp_request_sock {
 161         struct inet_request_sock dreq_inet_rsk;
 162         __u64                    dreq_iss;
 163         __u64                    dreq_gss;
 164         __u64                    dreq_isr;
 165         __u64                    dreq_gsr;
 166         __be32                   dreq_service;
 167         spinlock_t               dreq_lock;
 168         struct list_head         dreq_featneg;
 169         __u32                    dreq_timestamp_echo;
 170         __u32                    dreq_timestamp_time;
 171 };
 172
 173 static inline struct dccp_request_sock *dccp_rsk(const struct request_sock *req)
 174 {
 175         return (struct dccp_request_sock *)req;
 176 }
 177
 178 extern struct inet_timewait_death_row dccp_death_row;
 179
 180 extern int dccp_parse_options(struct sock *sk, struct dccp_request_sock *dreq,
 181                               struct sk_buff *skb);
 182
 183 struct dccp_options_received {
 184         u64     dccpor_ndp:48;
 185         u32     dccpor_timestamp;
 186         u32     dccpor_timestamp_echo;
 187         u32     dccpor_elapsed_time;
 188 };
 189
 190 struct ccid;
 191
 192 enum dccp_role {
 193         DCCP_ROLE_UNDEFINED,
 194         DCCP_ROLE_LISTEN,
 195         DCCP_ROLE_CLIENT,
 196         DCCP_ROLE_SERVER,
 197 };
 198
 199 struct dccp_service_list {
 200         __u32   dccpsl_nr;
 201         __be32  dccpsl_list[];
 202 };
 203
 204 #define DCCP_SERVICE_INVALID_VALUE htonl((__u32)-1)
 205 #define DCCP_SERVICE_CODE_IS_ABSENT             0
 206
 207 static inline bool dccp_list_has_service(const struct dccp_service_list *sl,
 208                                         const __be32 service)
 209 {
 210         if (likely(sl != NULL)) {
 211                 u32 i = sl->dccpsl_nr;
 212                 while (i--)
 213                         if (sl->dccpsl_list[i] == service)
 214                                 return true;
 215         }
 216         return false;
 217 }
 218
 219 struct dccp_ackvec;
 220
 221 /**
 222  * struct dccp_sock - DCCP socket state
 223  *
 224  * @dccps_swl - sequence number window low
 225  * @dccps_swh - sequence number window high
 226  * @dccps_awl - acknowledgement number window low
 227  * @dccps_awh - acknowledgement number window high
 228  * @dccps_iss - initial sequence number sent
 229  * @dccps_isr - initial sequence number received
 230  * @dccps_osr - first OPEN sequence number received
 231  * @dccps_gss - greatest sequence number sent
 232  * @dccps_gsr - greatest valid sequence number received
 233  * @dccps_gar - greatest valid ack number received on a non-Sync; initialized to %dccps_iss
 234  * @dccps_service - first (passive sock) or unique (active sock) service code
 235  * @dccps_service_list - second .. last service code on passive socket
 236  * @dccps_timestamp_echo - latest timestamp received on a TIMESTAMP option
 237  * @dccps_timestamp_time - time of receiving latest @dccps_timestamp_echo
 238  * @dccps_l_ack_ratio - feature-local Ack Ratio
 239  * @dccps_r_ack_ratio - feature-remote Ack Ratio
 240  * @dccps_l_seq_win - local Sequence Window (influences ack number validity)
 241  * @dccps_r_seq_win - remote Sequence Window (influences seq number validity)
 242  * @dccps_pcslen - sender   partial checksum coverage (via sockopt)
 243  * @dccps_pcrlen - receiver partial checksum coverage (via sockopt)
 244  * @dccps_send_ndp_count - local Send NDP Count feature (7.7.2)
 245  * @dccps_ndp_count - number of Non Data Packets since last data packet
 246  * @dccps_mss_cache - current value of MSS (path MTU minus header sizes)
 247  * @dccps_rate_last - timestamp for rate-limiting DCCP-Sync (RFC 4340, 7.5.4)
 248  * @dccps_featneg - tracks feature-negotiation state (mostly during handshake)
 249  * @dccps_hc_rx_ackvec - rx half connection ack vector
 250  * @dccps_hc_rx_ccid - CCID used for the receiver (or receiving half-connection)
 251  * @dccps_hc_tx_ccid - CCID used for the sender (or sending half-connection)
 252  * @dccps_options_received - parsed set of retrieved options
 253  * @dccps_qpolicy - TX dequeueing policy, one of %dccp_packet_dequeueing_policy
 254  * @dccps_tx_qlen - maximum length of the TX queue
 255  * @dccps_role - role of this sock, one of %dccp_role
 256  * @dccps_hc_rx_insert_options - receiver wants to add options when acking
 257  * @dccps_hc_tx_insert_options - sender wants to add options when sending
 258  * @dccps_server_timewait - server holds timewait state on close (RFC 4340, 8.3)
 259  * @dccps_sync_scheduled - flag which signals "send out-of-band message soon"
 260  * @dccps_xmitlet - tasklet scheduled by the TX CCID to dequeue data packets
 261  * @dccps_xmit_timer - used by the TX CCID to delay sending (rate-based pacing)
 262  * @dccps_syn_rtt - RTT sample from Request/Response exchange (in usecs)
 263  */
 264 struct dccp_sock {
 265         /* inet_connection_sock has to be the first member of dccp_sock */
 266         struct inet_connection_sock     dccps_inet_connection;
 267 #define dccps_syn_rtt                   dccps_inet_connection.icsk_ack.lrcvtime
 268         __u64                           dccps_swl;
 269         __u64                           dccps_swh;
 270         __u64                           dccps_awl;
 271         __u64                           dccps_awh;
 272         __u64                           dccps_iss;
 273         __u64                           dccps_isr;
 274         __u64                           dccps_osr;
 275         __u64                           dccps_gss;
 276         __u64                           dccps_gsr;
 277         __u64                           dccps_gar;
 278         __be32                          dccps_service;
 279         __u32                           dccps_mss_cache;
 280         struct dccp_service_list        *dccps_service_list;
 281         __u32                           dccps_timestamp_echo;
 282         __u32                           dccps_timestamp_time;
 283         __u16                           dccps_l_ack_ratio;
 284         __u16                           dccps_r_ack_ratio;
 285         __u64                           dccps_l_seq_win:48;
 286         __u64                           dccps_r_seq_win:48;
 287         __u8                            dccps_pcslen:4;
 288         __u8                            dccps_pcrlen:4;
 289         __u8                            dccps_send_ndp_count:1;
 290         __u64                           dccps_ndp_count:48;
 291         unsigned long                   dccps_rate_last;
 292         struct list_head                dccps_featneg;
 293         struct dccp_ackvec              *dccps_hc_rx_ackvec;
 294         struct ccid                     *dccps_hc_rx_ccid;
 295         struct ccid                     *dccps_hc_tx_ccid;
 296         struct dccp_options_received    dccps_options_received;
 297         __u8                            dccps_qpolicy;
 298         __u32                           dccps_tx_qlen;
 299         enum dccp_role                  dccps_role:2;
 300         __u8                            dccps_hc_rx_insert_options:1;
 301         __u8                            dccps_hc_tx_insert_options:1;
 302         __u8                            dccps_server_timewait:1;
 303         __u8                            dccps_sync_scheduled:1;
 304         struct tasklet_struct           dccps_xmitlet;
 305         struct timer_list               dccps_xmit_timer;
 306 };
 307
 308 static inline struct dccp_sock *dccp_sk(const struct sock *sk)
 309 {
 310         return (struct dccp_sock *)sk;
 311 }
 312
 313 static inline const char *dccp_role(const struct sock *sk)
 314 {
 315         switch (dccp_sk(sk)->dccps_role) {
 316         case DCCP_ROLE_UNDEFINED: return "undefined";
 317         case DCCP_ROLE_LISTEN:    return "listen";
 318         case DCCP_ROLE_SERVER:    return "server";
 319         case DCCP_ROLE_CLIENT:    return "client";
 320         }
 321         return NULL;
 322 }
 323
 324 extern void dccp_syn_ack_timeout(const struct request_sock *req);
 325
 326 #endif /* _LINUX_DCCP_H */