[DCCP]: Initial implementation

Development to this point was done on a subversion repository at:

http://oops.ghostprotocols.net:81/cgi-bin/viewcvs.cgi/dccp-2.6/

This repository will be kept at this site for the foreseable future,
so that interested parties can see the history of this code,
attributions, etc.

If I ever decide to take this offline I'll provide the full history at
some other suitable place.

Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 422 insertions, 0 deletions

diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h
new file mode 100644
index 000000000000..fb83454102c1
--- /dev/null
+++ b/net/dccp/dccp.h
@@ -0,0 +1,422 @@
+#ifndef _DCCP_H
+#define _DCCP_H
+/*
+ *  net/dccp/dccp.h
+ *
+ *  An implementation of the DCCP protocol
+ *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ *
+ *	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 <net/snmp.h>
+#include <net/sock.h>
+#include <net/tcp.h>
+
+#define DCCP_DEBUG
+
+#ifdef DCCP_DEBUG
+extern int dccp_debug;
+
+#define dccp_pr_debug(format, a...) \
+	do { if (dccp_debug) \
+		printk(KERN_DEBUG "%s: " format, __FUNCTION__ , ##a); \
+	} while (0)
+#define dccp_pr_debug_cat(format, a...) do { if (dccp_debug) printk(format, ##a); } while (0)
+#else
+#define dccp_pr_debug(format, a...)
+#define dccp_pr_debug_cat(format, a...)
+#endif
+
+extern struct inet_hashinfo dccp_hashinfo;
+
+extern atomic_t dccp_orphan_count;
+extern int dccp_tw_count;
+extern void dccp_tw_deschedule(struct inet_timewait_sock *tw);
+
+extern void dccp_time_wait(struct sock *sk, int state, int timeo);
+
+/* FIXME: Right size this */
+#define DCCP_MAX_OPT_LEN 128
+
+#define DCCP_MAX_PACKET_HDR 32
+
+#define MAX_DCCP_HEADER  (DCCP_MAX_PACKET_HDR + DCCP_MAX_OPT_LEN + MAX_HEADER)
+
+#define DCCP_TIMEWAIT_LEN (60 * HZ) /* how long to wait to destroy TIME-WAIT
+				     * state, about 60 seconds */
+
+/* draft-ietf-dccp-spec-11.txt initial RTO value */
+#define DCCP_TIMEOUT_INIT ((unsigned)(3 * HZ))
+
+/* Maximal interval between probes for local resources.  */
+#define DCCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ / 2U))
+
+#define DCCP_RTO_MAX ((unsigned)(120 * HZ)) /* FIXME: using TCP value */
+
+extern struct proto dccp_v4_prot;
+
+/* is seq1 < seq2 ? */
+static inline const  int before48(const u64 seq1, const u64 seq2)
+{
+	return (const s64)((seq1 << 16) - (seq2 << 16)) < 0;
+}
+
+/* is seq1 > seq2 ? */
+static inline const  int after48(const u64 seq1, const u64 seq2)
+{
+	return (const s64)((seq2 << 16) - (seq1 << 16)) < 0;
+}
+
+/* is seq2 <= seq1 <= seq3 ? */
+static inline const 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;
+}
+
+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];
+} __SNMP_MIB_ALIGN__;
+
+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_INC_STATS_USER(field) 	SNMP_INC_STATS_USER(dccp_statistics, field)
+#define DCCP_DEC_STATS(field)		SNMP_DEC_STATS(dccp_statistics, field)
+#define DCCP_ADD_STATS_BH(field, val)	SNMP_ADD_STATS_BH(dccp_statistics, field, val)
+#define DCCP_ADD_STATS_USER(field, val)	SNMP_ADD_STATS_USER(dccp_statistics, field, val)
+
+extern int  dccp_transmit_skb(struct sock *sk, struct sk_buff *skb);
+extern int  dccp_retransmit_skb(struct sock *sk, struct sk_buff *skb);
+
+extern int dccp_send_response(struct sock *sk);
+extern void dccp_send_ack(struct sock *sk);
+extern void dccp_send_delayed_ack(struct sock *sk);
+extern void dccp_send_sync(struct sock *sk, u64 seq);
+
+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 const char *dccp_state_name(const int state);
+
+static inline void dccp_set_state(struct sock *sk, const int state)
+{
+	const int oldstate = sk->sk_state;
+
+	dccp_pr_debug("%s(%p) %-10.10s -> %s\n",
+		      dccp_role(sk), sk,
+		      dccp_state_name(oldstate), dccp_state_name(state));
+	WARN_ON(state == oldstate);
+
+	switch (state) {
+	case DCCP_OPEN:
+		if (oldstate != DCCP_OPEN)
+			DCCP_INC_STATS(DCCP_MIB_CURRESTAB);
+		break;
+
+	case DCCP_CLOSED:
+		if (oldstate == DCCP_CLOSING || oldstate == DCCP_OPEN)
+			DCCP_INC_STATS(DCCP_MIB_ESTABRESETS);
+
+		sk->sk_prot->unhash(sk);
+		if (inet_csk(sk)->icsk_bind_hash != NULL &&
+		    !(sk->sk_userlocks & SOCK_BINDPORT_LOCK))
+			inet_put_port(&dccp_hashinfo, sk);
+		/* fall through */
+	default:
+		if (oldstate == DCCP_OPEN)
+			DCCP_DEC_STATS(DCCP_MIB_CURRESTAB);
+	}
+
+	/* Change state AFTER socket is unhashed to avoid closed
+	 * socket sitting in hash tables.
+	 */
+	sk->sk_state = state;
+}
+
+static inline void dccp_done(struct sock *sk)
+{
+	dccp_set_state(sk, DCCP_CLOSED);
+	dccp_clear_xmit_timers(sk);
+
+	sk->sk_shutdown = SHUTDOWN_MASK;
+
+	if (!sock_flag(sk, SOCK_DEAD))
+		sk->sk_state_change(sk);
+	else
+		inet_csk_destroy_sock(sk);
+}
+
+static inline void dccp_openreq_init(struct request_sock *req,
+				     struct dccp_sock *dp,
+				     struct sk_buff *skb)
+{
+	/*
+	 * FIXME: fill in the other req fields from the DCCP options
+	 * received
+	 */
+	inet_rsk(req)->rmt_port = dccp_hdr(skb)->dccph_sport;
+	inet_rsk(req)->acked	= 0;
+	req->rcv_wnd = 0;
+}
+
+extern void dccp_v4_send_check(struct sock *sk, struct dccp_hdr *dh, int len, 
+			       struct sk_buff *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 void dccp_v4_err(struct sk_buff *skb, u32);
+
+extern int dccp_v4_rcv(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 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 *optval, int *optlen);
+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 int	   dccp_setsockopt(struct sock *sk, int level, int optname,
+				   char *optval, int optlen);
+extern void	   dccp_shutdown(struct sock *sk, int how);
+
+extern int	   dccp_v4_checksum(struct sk_buff *skb);
+
+extern int	   dccp_v4_send_reset(struct sock *sk, enum dccp_reset_codes code);
+extern void	   dccp_send_close(struct sock *sk);
+
+struct dccp_skb_cb {
+	__u8 dccpd_type;
+	__u8 dccpd_reset_code;
+	__u8 dccpd_service;
+	__u8 dccpd_ccval;
+	__u64 dccpd_seq;
+	__u64 dccpd_ack_seq;
+	int  dccpd_opt_len;
+};
+
+#define DCCP_SKB_CB(__skb) ((struct dccp_skb_cb *)&((__skb)->cb[0]))
+
+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;
+}
+
+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_MAX_SEQNO ((((u64)1) << 48) - 1)
+#define DCCP_PKT_WITHOUT_ACK_SEQ (DCCP_MAX_SEQNO << 2)
+
+static inline void dccp_set_seqno(u64 *seqno, u64 value)
+{
+	if (value > DCCP_MAX_SEQNO)
+		value -= DCCP_MAX_SEQNO + 1;
+	*seqno = value;
+}
+
+static inline u64 dccp_delta_seqno(u64 seqno1, u64 seqno2)
+{
+	return ((seqno2 << 16) - (seqno1 << 16)) >> 16;
+}
+
+static inline void dccp_inc_seqno(u64 *seqno)
+{
+	if (++*seqno > DCCP_MAX_SEQNO)
+		*seqno = 0;
+}
+
+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));
+
+#if defined(__LITTLE_ENDIAN_BITFIELD)
+	dh->dccph_seq	   = htonl((gss >> 32)) >> 8;
+#elif defined(__BIG_ENDIAN_BITFIELD)
+	dh->dccph_seq	   = htonl((gss >> 32));
+#else
+#error  "Adjust your <asm/byteorder.h> defines"
+#endif
+	dhx->dccph_seq_low = htonl(gss & 0xffffffff);
+}
+
+static inline void dccp_hdr_set_ack(struct dccp_hdr_ack_bits *dhack, const u64 gsr)
+{
+#if defined(__LITTLE_ENDIAN_BITFIELD)
+	dhack->dccph_ack_nr_high = htonl((gsr >> 32)) >> 8;
+#elif defined(__BIG_ENDIAN_BITFIELD)
+	dhack->dccph_ack_nr_high = htonl((gsr >> 32));
+#else
+#error  "Adjust your <asm/byteorder.h> defines"
+#endif
+	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);
+	u64 tmp_gsr;
+
+	dccp_set_seqno(&tmp_gsr, dp->dccps_gsr + 1 - (dp->dccps_options.dccpo_sequence_window / 4));
+	dp->dccps_gsr = seq;
+	dccp_set_seqno(&dp->dccps_swl, max48(tmp_gsr, dp->dccps_isr));
+	dccp_set_seqno(&dp->dccps_swh,
+		       dp->dccps_gsr + (3 * dp->dccps_options.dccpo_sequence_window) / 4);
+}
+
+static inline void dccp_update_gss(struct sock *sk, u64 seq)
+{
+	struct dccp_sock *dp = dccp_sk(sk);
+	u64 tmp_gss;
+
+	dccp_set_seqno(&tmp_gss, dp->dccps_gss - dp->dccps_options.dccpo_sequence_window + 1);
+	dp->dccps_awl = max48(tmp_gss, dp->dccps_iss);
+	dp->dccps_awh = dp->dccps_gss = seq;
+}
+
+extern void dccp_insert_options(struct sock *sk, struct sk_buff *skb);
+extern void dccp_insert_option_elapsed_time(struct sock *sk,
+					    struct sk_buff *skb,
+					    u32 elapsed_time);
+extern void dccp_insert_option(struct sock *sk, struct sk_buff *skb,
+			       unsigned char option,
+			       const void *value, unsigned char len);
+
+extern struct socket *dccp_ctl_socket;
+
+#define DCCP_ACKPKTS_STATE_RECEIVED	0
+#define DCCP_ACKPKTS_STATE_ECN_MARKED	(1 << 6)
+#define DCCP_ACKPKTS_STATE_NOT_RECEIVED	(3 << 6)
+
+#define DCCP_ACKPKTS_STATE_MASK		0xC0 /* 11000000 */
+#define DCCP_ACKPKTS_LEN_MASK		0x3F /* 00111111 */
+
+/** struct dccp_ackpkts - acknowledgeable packets
+ *
+ * This data structure is the one defined in the DCCP draft
+ * Appendix A.
+ *
+ * @dccpap_buf_head - circular buffer head
+ * @dccpap_buf_tail - circular buffer tail
+ * @dccpap_buf_ackno - ack # of the most recent packet acknoldgeable in the buffer (i.e. %dccpap_buf_head)
+ * @dccpap_buf_nonce - the one-bit sum of the ECN Nonces on all packets acked by the buffer with State 0
+ *
+ * Additionally, the HC-Receiver must keep some information about the
+ * Ack Vectors it has recently sent. For each packet sent carrying an
+ * Ack Vector, it remembers four variables:
+ *
+ * @dccpap_ack_seqno - the Sequence Number used for the packet (HC-Receiver seqno)
+ * @dccpap_ack_ptr - the value of buf_head at the time of acknowledgement.
+ * @dccpap_ack_ackno - the Acknowledgement Number used for the packet (HC-Sender seqno)
+ * @dccpap_ack_nonce - the one-bit sum of the ECN Nonces for all State 0.
+ *
+ * @dccpap_buf_len - circular buffer length
+ * @dccpap_buf - circular buffer of acknowledgeable packets
+ */
+struct dccp_ackpkts {
+	unsigned int		dccpap_buf_head;
+	unsigned int		dccpap_buf_tail;
+	u64			dccpap_buf_ackno;
+	u64			dccpap_ack_seqno;
+	u64			dccpap_ack_ackno;
+	unsigned int		dccpap_ack_ptr;
+	unsigned int		dccpap_buf_vector_len;
+	unsigned int		dccpap_ack_vector_len;
+	unsigned int		dccpap_buf_len;
+	unsigned long           dccpap_time;
+	u8			dccpap_buf_nonce;
+	u8			dccpap_ack_nonce;
+	u8			dccpap_buf[0];
+};
+
+extern struct dccp_ackpkts *dccp_ackpkts_alloc(unsigned int len, int priority);
+extern void dccp_ackpkts_free(struct dccp_ackpkts *ap);
+extern int dccp_ackpkts_add(struct dccp_ackpkts *ap, u64 ackno, u8 state);
+extern void dccp_ackpkts_check_rcv_ackno(struct dccp_ackpkts *ap,
+					 struct sock *sk, u64 ackno);
+
+#ifdef DCCP_DEBUG
+extern void dccp_ackvector_print(const u64 ackno,
+				 const unsigned char *vector, int len);
+extern void dccp_ackpkts_print(const struct dccp_ackpkts *ap);
+#else
+static inline void dccp_ackvector_print(const u64 ackno,
+					const unsigned char *vector,
+					int len) { }
+static inline void dccp_ackpkts_print(const struct dccp_ackpkts *ap) { }
+#endif
+
+#endif /* _DCCP_H */