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Diffstat (limited to 'net/dccp/dccp.h')
| -rw-r--r-- | net/dccp/dccp.h | 507 |
1 files changed, 507 insertions, 0 deletions
diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h new file mode 100644 index 00000000..29d6bb62 --- /dev/null +++ b/net/dccp/dccp.h @@ -0,0 +1,507 @@ +#ifndef _DCCP_H +#define _DCCP_H +/* + * net/dccp/dccp.h + * + * An implementation of the DCCP protocol + * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br> + * Copyright (c) 2005-6 Ian McDonald <ian.mcdonald@jandi.co.nz> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/dccp.h> +#include <linux/ktime.h> +#include <net/snmp.h> +#include <net/sock.h> +#include <net/tcp.h> +#include "ackvec.h" + +/* + * DCCP - specific warning and debugging macros. + */ +#define DCCP_WARN(fmt, a...) LIMIT_NETDEBUG(KERN_WARNING "%s: " fmt, \ + __func__, ##a) +#define DCCP_CRIT(fmt, a...) printk(KERN_CRIT fmt " at %s:%d/%s()\n", ##a, \ + __FILE__, __LINE__, __func__) +#define DCCP_BUG(a...) do { DCCP_CRIT("BUG: " a); dump_stack(); } while(0) +#define DCCP_BUG_ON(cond) do { if (unlikely((cond) != 0)) \ + DCCP_BUG("\"%s\" holds (exception!)", \ + __stringify(cond)); \ + } while (0) + +#define DCCP_PRINTK(enable, fmt, args...) do { if (enable) \ + printk(fmt, ##args); \ + } while(0) +#define DCCP_PR_DEBUG(enable, fmt, a...) DCCP_PRINTK(enable, KERN_DEBUG \ + "%s: " fmt, __func__, ##a) + +#ifdef CONFIG_IP_DCCP_DEBUG +extern bool dccp_debug; +#define dccp_pr_debug(format, a...) DCCP_PR_DEBUG(dccp_debug, format, ##a) +#define dccp_pr_debug_cat(format, a...) DCCP_PRINTK(dccp_debug, format, ##a) +#define dccp_debug(fmt, a...) dccp_pr_debug_cat(KERN_DEBUG fmt, ##a) +#else +#define dccp_pr_debug(format, a...) +#define dccp_pr_debug_cat(format, a...) +#define dccp_debug(format, a...) +#endif + +extern struct inet_hashinfo dccp_hashinfo; + +extern struct percpu_counter dccp_orphan_count; + +extern void dccp_time_wait(struct sock *sk, int state, int timeo); + +/* + * Set safe upper bounds for header and option length. Since Data Offset is 8 + * bits (RFC 4340, sec. 5.1), the total header length can never be more than + * 4 * 255 = 1020 bytes. The largest possible header length is 28 bytes (X=1): + * - DCCP-Response with ACK Subheader and 4 bytes of Service code OR + * - DCCP-Reset with ACK Subheader and 4 bytes of Reset Code fields + * Hence a safe upper bound for the maximum option length is 1020-28 = 992 + */ +#define MAX_DCCP_SPECIFIC_HEADER (255 * sizeof(uint32_t)) +#define DCCP_MAX_PACKET_HDR 28 +#define DCCP_MAX_OPT_LEN (MAX_DCCP_SPECIFIC_HEADER - DCCP_MAX_PACKET_HDR) +#define MAX_DCCP_HEADER (MAX_DCCP_SPECIFIC_HEADER + MAX_HEADER) + +/* Upper bound for initial feature-negotiation overhead (padded to 32 bits) */ +#define DCCP_FEATNEG_OVERHEAD (32 * sizeof(uint32_t)) + +#define DCCP_TIMEWAIT_LEN (60 * HZ) /* how long to wait to destroy TIME-WAIT + * state, about 60 seconds */ + +/* RFC 1122, 4.2.3.1 initial RTO value */ +#define DCCP_TIMEOUT_INIT ((unsigned)(3 * HZ)) + +/* + * The maximum back-off value for retransmissions. This is needed for + * - retransmitting client-Requests (sec. 8.1.1), + * - retransmitting Close/CloseReq when closing (sec. 8.3), + * - feature-negotiation retransmission (sec. 6.6.3), + * - Acks in client-PARTOPEN state (sec. 8.1.5). + */ +#define DCCP_RTO_MAX ((unsigned)(64 * HZ)) + +/* + * RTT sampling: sanity bounds and fallback RTT value from RFC 4340, section 3.4 + */ +#define DCCP_SANE_RTT_MIN 100 +#define DCCP_FALLBACK_RTT (USEC_PER_SEC / 5) +#define DCCP_SANE_RTT_MAX (3 * USEC_PER_SEC) + +/* sysctl variables for DCCP */ +extern int sysctl_dccp_request_retries; +extern int sysctl_dccp_retries1; +extern int sysctl_dccp_retries2; +extern int sysctl_dccp_tx_qlen; +extern int sysctl_dccp_sync_ratelimit; + +/* + * 48-bit sequence number arithmetic (signed and unsigned) + */ +#define INT48_MIN 0x800000000000LL /* 2^47 */ +#define UINT48_MAX 0xFFFFFFFFFFFFLL /* 2^48 - 1 */ +#define COMPLEMENT48(x) (0x1000000000000LL - (x)) /* 2^48 - x */ +#define TO_SIGNED48(x) (((x) < INT48_MIN)? (x) : -COMPLEMENT48( (x))) +#define TO_UNSIGNED48(x) (((x) >= 0)? (x) : COMPLEMENT48(-(x))) +#define ADD48(a, b) (((a) + (b)) & UINT48_MAX) +#define SUB48(a, b) ADD48((a), COMPLEMENT48(b)) + +static inline void dccp_set_seqno(u64 *seqno, u64 value) +{ + *seqno = value & UINT48_MAX; +} + +static inline void dccp_inc_seqno(u64 *seqno) +{ + *seqno = ADD48(*seqno, 1); +} + +/* signed mod-2^48 distance: pos. if seqno1 < seqno2, neg. if seqno1 > seqno2 */ +static inline s64 dccp_delta_seqno(const u64 seqno1, const u64 seqno2) +{ + u64 delta = SUB48(seqno2, seqno1); + + return TO_SIGNED48(delta); +} + +/* is seq1 < seq2 ? */ +static inline int before48(const u64 seq1, const u64 seq2) +{ + return (s64)((seq2 << 16) - (seq1 << 16)) > 0; +} + +/* is seq1 > seq2 ? */ +#define after48(seq1, seq2) before48(seq2, seq1) + +/* is seq2 <= seq1 <= seq3 ? */ +static inline int between48(const u64 seq1, const u64 seq2, const u64 seq3) +{ + return (seq3 << 16) - (seq2 << 16) >= (seq1 << 16) - (seq2 << 16); +} + +static inline u64 max48(const u64 seq1, const u64 seq2) +{ + return after48(seq1, seq2) ? seq1 : seq2; +} + +/** + * dccp_loss_count - Approximate the number of lost data packets in a burst loss + * @s1: last known sequence number before the loss ('hole') + * @s2: first sequence number seen after the 'hole' + * @ndp: NDP count on packet with sequence number @s2 + */ +static inline u64 dccp_loss_count(const u64 s1, const u64 s2, const u64 ndp) +{ + s64 delta = dccp_delta_seqno(s1, s2); + + WARN_ON(delta < 0); + delta -= ndp + 1; + + return delta > 0 ? delta : 0; +} + +/** + * dccp_loss_free - Evaluate condition for data loss from RFC 4340, 7.7.1 + */ +static inline bool dccp_loss_free(const u64 s1, const u64 s2, const u64 ndp) +{ + return dccp_loss_count(s1, s2, ndp) == 0; +} + +enum { + DCCP_MIB_NUM = 0, + DCCP_MIB_ACTIVEOPENS, /* ActiveOpens */ + DCCP_MIB_ESTABRESETS, /* EstabResets */ + DCCP_MIB_CURRESTAB, /* CurrEstab */ + DCCP_MIB_OUTSEGS, /* OutSegs */ + DCCP_MIB_OUTRSTS, + DCCP_MIB_ABORTONTIMEOUT, + DCCP_MIB_TIMEOUTS, + DCCP_MIB_ABORTFAILED, + DCCP_MIB_PASSIVEOPENS, + DCCP_MIB_ATTEMPTFAILS, + DCCP_MIB_OUTDATAGRAMS, + DCCP_MIB_INERRS, + DCCP_MIB_OPTMANDATORYERROR, + DCCP_MIB_INVALIDOPT, + __DCCP_MIB_MAX +}; + +#define DCCP_MIB_MAX __DCCP_MIB_MAX +struct dccp_mib { + unsigned long mibs[DCCP_MIB_MAX]; +}; + +DECLARE_SNMP_STAT(struct dccp_mib, dccp_statistics); +#define DCCP_INC_STATS(field) SNMP_INC_STATS(dccp_statistics, field) +#define DCCP_INC_STATS_BH(field) SNMP_INC_STATS_BH(dccp_statistics, field) +#define DCCP_DEC_STATS(field) SNMP_DEC_STATS(dccp_statistics, field) + +/* + * Checksumming routines + */ +static inline unsigned int dccp_csum_coverage(const struct sk_buff *skb) +{ + const struct dccp_hdr* dh = dccp_hdr(skb); + + if (dh->dccph_cscov == 0) + return skb->len; + return (dh->dccph_doff + dh->dccph_cscov - 1) * sizeof(u32); +} + +static inline void dccp_csum_outgoing(struct sk_buff *skb) +{ + unsigned int cov = dccp_csum_coverage(skb); + + if (cov >= skb->len) + dccp_hdr(skb)->dccph_cscov = 0; + + skb->csum = skb_checksum(skb, 0, (cov > skb->len)? skb->len : cov, 0); +} + +extern void dccp_v4_send_check(struct sock *sk, struct sk_buff *skb); + +extern int dccp_retransmit_skb(struct sock *sk); + +extern void dccp_send_ack(struct sock *sk); +extern void dccp_reqsk_send_ack(struct sock *sk, struct sk_buff *skb, + struct request_sock *rsk); + +extern void dccp_send_sync(struct sock *sk, const u64 seq, + const enum dccp_pkt_type pkt_type); + +/* + * TX Packet Dequeueing Interface + */ +extern void dccp_qpolicy_push(struct sock *sk, struct sk_buff *skb); +extern bool dccp_qpolicy_full(struct sock *sk); +extern void dccp_qpolicy_drop(struct sock *sk, struct sk_buff *skb); +extern struct sk_buff *dccp_qpolicy_top(struct sock *sk); +extern struct sk_buff *dccp_qpolicy_pop(struct sock *sk); +extern bool dccp_qpolicy_param_ok(struct sock *sk, __be32 param); + +/* + * TX Packet Output and TX Timers + */ +extern void dccp_write_xmit(struct sock *sk); +extern void dccp_write_space(struct sock *sk); +extern void dccp_flush_write_queue(struct sock *sk, long *time_budget); + +extern void dccp_init_xmit_timers(struct sock *sk); +static inline void dccp_clear_xmit_timers(struct sock *sk) +{ + inet_csk_clear_xmit_timers(sk); +} + +extern unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu); + +extern const char *dccp_packet_name(const int type); + +extern void dccp_set_state(struct sock *sk, const int state); +extern void dccp_done(struct sock *sk); + +extern int dccp_reqsk_init(struct request_sock *rq, struct dccp_sock const *dp, + struct sk_buff const *skb); + +extern int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb); + +extern struct sock *dccp_create_openreq_child(struct sock *sk, + const struct request_sock *req, + const struct sk_buff *skb); + +extern int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb); + +extern struct sock *dccp_v4_request_recv_sock(struct sock *sk, + struct sk_buff *skb, + struct request_sock *req, + struct dst_entry *dst); +extern struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb, + struct request_sock *req, + struct request_sock **prev); + +extern int dccp_child_process(struct sock *parent, struct sock *child, + struct sk_buff *skb); +extern int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb, + struct dccp_hdr *dh, unsigned len); +extern int dccp_rcv_established(struct sock *sk, struct sk_buff *skb, + const struct dccp_hdr *dh, const unsigned len); + +extern int dccp_init_sock(struct sock *sk, const __u8 ctl_sock_initialized); +extern void dccp_destroy_sock(struct sock *sk); + +extern void dccp_close(struct sock *sk, long timeout); +extern struct sk_buff *dccp_make_response(struct sock *sk, + struct dst_entry *dst, + struct request_sock *req); + +extern int dccp_connect(struct sock *sk); +extern int dccp_disconnect(struct sock *sk, int flags); +extern int dccp_getsockopt(struct sock *sk, int level, int optname, + char __user *optval, int __user *optlen); +extern int dccp_setsockopt(struct sock *sk, int level, int optname, + char __user *optval, unsigned int optlen); +#ifdef CONFIG_COMPAT +extern int compat_dccp_getsockopt(struct sock *sk, + int level, int optname, + char __user *optval, int __user *optlen); +extern int compat_dccp_setsockopt(struct sock *sk, + int level, int optname, + char __user *optval, unsigned int optlen); +#endif +extern int dccp_ioctl(struct sock *sk, int cmd, unsigned long arg); +extern int dccp_sendmsg(struct kiocb *iocb, struct sock *sk, + struct msghdr *msg, size_t size); +extern int dccp_recvmsg(struct kiocb *iocb, struct sock *sk, + struct msghdr *msg, size_t len, int nonblock, + int flags, int *addr_len); +extern void dccp_shutdown(struct sock *sk, int how); +extern int inet_dccp_listen(struct socket *sock, int backlog); +extern unsigned int dccp_poll(struct file *file, struct socket *sock, + poll_table *wait); +extern int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, + int addr_len); + +extern struct sk_buff *dccp_ctl_make_reset(struct sock *sk, + struct sk_buff *skb); +extern int dccp_send_reset(struct sock *sk, enum dccp_reset_codes code); +extern void dccp_send_close(struct sock *sk, const int active); +extern int dccp_invalid_packet(struct sk_buff *skb); +extern u32 dccp_sample_rtt(struct sock *sk, long delta); + +static inline int dccp_bad_service_code(const struct sock *sk, + const __be32 service) +{ + const struct dccp_sock *dp = dccp_sk(sk); + + if (dp->dccps_service == service) + return 0; + return !dccp_list_has_service(dp->dccps_service_list, service); +} + +/** + * dccp_skb_cb - DCCP per-packet control information + * @dccpd_type: one of %dccp_pkt_type (or unknown) + * @dccpd_ccval: CCVal field (5.1), see e.g. RFC 4342, 8.1 + * @dccpd_reset_code: one of %dccp_reset_codes + * @dccpd_reset_data: Data1..3 fields (depend on @dccpd_reset_code) + * @dccpd_opt_len: total length of all options (5.8) in the packet + * @dccpd_seq: sequence number + * @dccpd_ack_seq: acknowledgment number subheader field value + * This is used for transmission as well as for reception. + */ +struct dccp_skb_cb { + union { + struct inet_skb_parm h4; +#if IS_ENABLED(CONFIG_IPV6) + struct inet6_skb_parm h6; +#endif + } header; + __u8 dccpd_type:4; + __u8 dccpd_ccval:4; + __u8 dccpd_reset_code, + dccpd_reset_data[3]; + __u16 dccpd_opt_len; + __u64 dccpd_seq; + __u64 dccpd_ack_seq; +}; + +#define DCCP_SKB_CB(__skb) ((struct dccp_skb_cb *)&((__skb)->cb[0])) + +/* RFC 4340, sec. 7.7 */ +static inline int dccp_non_data_packet(const struct sk_buff *skb) +{ + const __u8 type = DCCP_SKB_CB(skb)->dccpd_type; + + return type == DCCP_PKT_ACK || + type == DCCP_PKT_CLOSE || + type == DCCP_PKT_CLOSEREQ || + type == DCCP_PKT_RESET || + type == DCCP_PKT_SYNC || + type == DCCP_PKT_SYNCACK; +} + +/* RFC 4340, sec. 7.7 */ +static inline int dccp_data_packet(const struct sk_buff *skb) +{ + const __u8 type = DCCP_SKB_CB(skb)->dccpd_type; + + return type == DCCP_PKT_DATA || + type == DCCP_PKT_DATAACK || + type == DCCP_PKT_REQUEST || + type == DCCP_PKT_RESPONSE; +} + +static inline int dccp_packet_without_ack(const struct sk_buff *skb) +{ + const __u8 type = DCCP_SKB_CB(skb)->dccpd_type; + + return type == DCCP_PKT_DATA || type == DCCP_PKT_REQUEST; +} + +#define DCCP_PKT_WITHOUT_ACK_SEQ (UINT48_MAX << 2) + +static inline void dccp_hdr_set_seq(struct dccp_hdr *dh, const u64 gss) +{ + struct dccp_hdr_ext *dhx = (struct dccp_hdr_ext *)((void *)dh + + sizeof(*dh)); + dh->dccph_seq2 = 0; + dh->dccph_seq = htons((gss >> 32) & 0xfffff); + dhx->dccph_seq_low = htonl(gss & 0xffffffff); +} + +static inline void dccp_hdr_set_ack(struct dccp_hdr_ack_bits *dhack, + const u64 gsr) +{ + dhack->dccph_reserved1 = 0; + dhack->dccph_ack_nr_high = htons(gsr >> 32); + dhack->dccph_ack_nr_low = htonl(gsr & 0xffffffff); +} + +static inline void dccp_update_gsr(struct sock *sk, u64 seq) +{ + struct dccp_sock *dp = dccp_sk(sk); + + if (after48(seq, dp->dccps_gsr)) + dp->dccps_gsr = seq; + /* Sequence validity window depends on remote Sequence Window (7.5.1) */ + dp->dccps_swl = SUB48(ADD48(dp->dccps_gsr, 1), dp->dccps_r_seq_win / 4); + /* + * Adjust SWL so that it is not below ISR. In contrast to RFC 4340, + * 7.5.1 we perform this check beyond the initial handshake: W/W' are + * always > 32, so for the first W/W' packets in the lifetime of a + * connection we always have to adjust SWL. + * A second reason why we are doing this is that the window depends on + * the feature-remote value of Sequence Window: nothing stops the peer + * from updating this value while we are busy adjusting SWL for the + * first W packets (we would have to count from scratch again then). + * Therefore it is safer to always make sure that the Sequence Window + * is not artificially extended by a peer who grows SWL downwards by + * continually updating the feature-remote Sequence-Window. + * If sequence numbers wrap it is bad luck. But that will take a while + * (48 bit), and this measure prevents Sequence-number attacks. + */ + if (before48(dp->dccps_swl, dp->dccps_isr)) + dp->dccps_swl = dp->dccps_isr; + dp->dccps_swh = ADD48(dp->dccps_gsr, (3 * dp->dccps_r_seq_win) / 4); +} + +static inline void dccp_update_gss(struct sock *sk, u64 seq) +{ + struct dccp_sock *dp = dccp_sk(sk); + + dp->dccps_gss = seq; + /* Ack validity window depends on local Sequence Window value (7.5.1) */ + dp->dccps_awl = SUB48(ADD48(dp->dccps_gss, 1), dp->dccps_l_seq_win); + /* Adjust AWL so that it is not below ISS - see comment above for SWL */ + if (before48(dp->dccps_awl, dp->dccps_iss)) + dp->dccps_awl = dp->dccps_iss; + dp->dccps_awh = dp->dccps_gss; +} + +static inline int dccp_ackvec_pending(const struct sock *sk) +{ + return dccp_sk(sk)->dccps_hc_rx_ackvec != NULL && + !dccp_ackvec_is_empty(dccp_sk(sk)->dccps_hc_rx_ackvec); +} + +static inline int dccp_ack_pending(const struct sock *sk) +{ + return dccp_ackvec_pending(sk) || inet_csk_ack_scheduled(sk); +} + +extern int dccp_feat_signal_nn_change(struct sock *sk, u8 feat, u64 nn_val); +extern int dccp_feat_finalise_settings(struct dccp_sock *dp); +extern int dccp_feat_server_ccid_dependencies(struct dccp_request_sock *dreq); +extern int dccp_feat_insert_opts(struct dccp_sock*, struct dccp_request_sock*, + struct sk_buff *skb); +extern int dccp_feat_activate_values(struct sock *sk, struct list_head *fn); +extern void dccp_feat_list_purge(struct list_head *fn_list); + +extern int dccp_insert_options(struct sock *sk, struct sk_buff *skb); +extern int dccp_insert_options_rsk(struct dccp_request_sock*, struct sk_buff*); +extern int dccp_insert_option_elapsed_time(struct sk_buff *skb, u32 elapsed); +extern u32 dccp_timestamp(void); +extern void dccp_timestamping_init(void); +extern int dccp_insert_option(struct sk_buff *skb, unsigned char option, + const void *value, unsigned char len); + +#ifdef CONFIG_SYSCTL +extern int dccp_sysctl_init(void); +extern void dccp_sysctl_exit(void); +#else +static inline int dccp_sysctl_init(void) +{ + return 0; +} + +static inline void dccp_sysctl_exit(void) +{ +} +#endif + +#endif /* _DCCP_H */ |