/* SPDX-License-Identifier: GPL-2.0-only */ #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> */ #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, ...) \ net_warn_ratelimited("%s: " fmt, __func__, ##__VA_ARGS__) #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; 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 int)(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 int)(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(field) __SNMP_INC_STATS(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); } void dccp_v4_send_check(struct sock *sk, struct sk_buff *skb); int dccp_retransmit_skb(struct sock *sk); void dccp_send_ack(struct sock *sk); void dccp_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb, struct request_sock *rsk); void dccp_send_sync(struct sock *sk, const u64 seq, const enum dccp_pkt_type pkt_type); /* * TX Packet Dequeueing Interface */ void dccp_qpolicy_push(struct sock *sk, struct sk_buff *skb); bool dccp_qpolicy_full(struct sock *sk); void dccp_qpolicy_drop(struct sock *sk, struct sk_buff *skb); struct sk_buff *dccp_qpolicy_top(struct sock *sk); struct sk_buff *dccp_qpolicy_pop(struct sock *sk); bool dccp_qpolicy_param_ok(struct sock *sk, __be32 param); /* * TX Packet Output and TX Timers */ void dccp_write_xmit(struct sock *sk); void dccp_write_space(struct sock *sk); void dccp_flush_write_queue(struct sock *sk, long *time_budget); void dccp_init_xmit_timers(struct sock *sk); static inline void dccp_clear_xmit_timers(struct sock *sk) { inet_csk_clear_xmit_timers(sk); } unsigned int dccp_sync_mss(struct sock *sk, u32 pmtu); const char *dccp_packet_name(const int type); void dccp_set_state(struct sock *sk, const int state); void dccp_done(struct sock *sk); int dccp_reqsk_init(struct request_sock *rq, struct dccp_sock const *dp, struct sk_buff const *skb); int dccp_v4_conn_request(struct sock *sk, struct sk_buff *skb); struct sock *dccp_create_openreq_child(const struct sock *sk, const struct request_sock *req, const struct sk_buff *skb); int dccp_v4_do_rcv(struct sock *sk, struct sk_buff *skb); struct sock *dccp_v4_request_recv_sock(const struct sock *sk, struct sk_buff *skb, struct request_sock *req, struct dst_entry *dst, struct request_sock *req_unhash, bool *own_req); struct sock *dccp_check_req(struct sock *sk, struct sk_buff *skb, struct request_sock *req); int dccp_child_process(struct sock *parent, struct sock *child, struct sk_buff *skb); int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb, struct dccp_hdr *dh, unsigned int len); int dccp_rcv_established(struct sock *sk, struct sk_buff *skb, const struct dccp_hdr *dh, const unsigned int len); int dccp_init_sock(struct sock *sk, const __u8 ctl_sock_initialized); void dccp_destroy_sock(struct sock *sk); void dccp_close(struct sock *sk, long timeout); struct sk_buff *dccp_make_response(const struct sock *sk, struct dst_entry *dst, struct request_sock *req); int dccp_connect(struct sock *sk); int dccp_disconnect(struct sock *sk, int flags); int dccp_getsockopt(struct sock *sk, int level, int optname, char __user *optval, int __user *optlen); int dccp_setsockopt(struct sock *sk, int level, int optname, char __user *optval, unsigned int optlen); #ifdef CONFIG_COMPAT int compat_dccp_getsockopt(struct sock *sk, int level, int optname, char __user *optval, int __user *optlen); int compat_dccp_setsockopt(struct sock *sk, int level, int optname, char __user *optval, unsigned int optlen); #endif int dccp_ioctl(struct sock *sk, int cmd, unsigned long arg); int dccp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size); int dccp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock, int flags, int *addr_len); void dccp_shutdown(struct sock *sk, int how); int inet_dccp_listen(struct socket *sock, int backlog); __poll_t dccp_poll(struct file *file, struct socket *sock, poll_table *wait); int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len); void dccp_req_err(struct sock *sk, u64 seq); struct sk_buff *dccp_ctl_make_reset(struct sock *sk, struct sk_buff *skb); int dccp_send_reset(struct sock *sk, enum dccp_reset_codes code); void dccp_send_close(struct sock *sk, const int active); int dccp_invalid_packet(struct sk_buff *skb); u32 dccp_sample_rtt(struct sock *sk, long delta); static inline bool 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 false; 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); } int dccp_feat_signal_nn_change(struct sock *sk, u8 feat, u64 nn_val); int dccp_feat_finalise_settings(struct dccp_sock *dp); int dccp_feat_server_ccid_dependencies(struct dccp_request_sock *dreq); int dccp_feat_insert_opts(struct dccp_sock*, struct dccp_request_sock*, struct sk_buff *skb); int dccp_feat_activate_values(struct sock *sk, struct list_head *fn); void dccp_feat_list_purge(struct list_head *fn_list); int dccp_insert_options(struct sock *sk, struct sk_buff *skb); int dccp_insert_options_rsk(struct dccp_request_sock *, struct sk_buff *); u32 dccp_timestamp(void); void dccp_timestamping_init(void); int dccp_insert_option(struct sk_buff *skb, unsigned char option, const void *value, unsigned char len); #ifdef CONFIG_SYSCTL int dccp_sysctl_init(void); 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 */