[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>

4 files changed, 435 insertions, 0 deletions

diff --git a/include/linux/dccp.h b/include/linux/dccp.h
new file mode 100644
index 00000000000..e3b4bf7346b
--- /dev/null
+++ b/include/linux/dccp.h
@@ -0,0 +1,432 @@
+#ifndef _LINUX_DCCP_H
+#define _LINUX_DCCP_H
+
+#include <linux/in.h>
+#include <linux/list.h>
+#include <linux/types.h>
+#include <linux/uio.h>
+#include <linux/workqueue.h>
+
+#include <net/inet_connection_sock.h>
+#include <net/sock.h>
+#include <net/tcp_states.h>
+#include <net/tcp.h>
+
+/* FIXME: this is utterly wrong */
+struct sockaddr_dccp {
+	struct sockaddr_in	in;
+	unsigned int		service;
+};
+
+enum dccp_state {
+	DCCP_OPEN	= TCP_ESTABLISHED,
+	DCCP_REQUESTING	= TCP_SYN_SENT,
+	DCCP_PARTOPEN	= TCP_FIN_WAIT1, /* FIXME:
+					    This mapping is horrible, but TCP has
+					    no matching state for DCCP_PARTOPEN,
+					    as TCP_SYN_RECV is already used by
+					    DCCP_RESPOND, why don't stop using TCP
+					    mapping of states? OK, now we don't use
+					    sk_stream_sendmsg anymore, so doesn't
+					    seem to exist any reason for us to
+					    do the TCP mapping here */
+	DCCP_LISTEN	= TCP_LISTEN,
+	DCCP_RESPOND	= TCP_SYN_RECV,
+	DCCP_CLOSING	= TCP_CLOSING,
+	DCCP_TIME_WAIT	= TCP_TIME_WAIT,
+	DCCP_CLOSED	= TCP_CLOSE,
+	DCCP_MAX_STATES = TCP_MAX_STATES,
+};
+
+#define DCCP_STATE_MASK 0xf
+#define DCCP_ACTION_FIN (1<<7)
+
+enum {
+	DCCPF_OPEN	 = TCPF_ESTABLISHED,
+	DCCPF_REQUESTING = TCPF_SYN_SENT,
+	DCCPF_PARTOPEN	 = TCPF_FIN_WAIT1,
+	DCCPF_LISTEN	 = TCPF_LISTEN,
+	DCCPF_RESPOND	 = TCPF_SYN_RECV,
+	DCCPF_CLOSING	 = TCPF_CLOSING,
+	DCCPF_TIME_WAIT	 = TCPF_TIME_WAIT,
+	DCCPF_CLOSED	 = TCPF_CLOSE,
+};
+
+/**
+ * struct dccp_hdr - generic part of DCCP packet header
+ *
+ * @dccph_sport - Relevant port on the endpoint that sent this packet
+ * @dccph_dport - Relevant port on the other endpoint
+ * @dccph_doff - Data Offset from the start of the DCCP header, in 32-bit words
+ * @dccph_ccval - Used by the HC-Sender CCID
+ * @dccph_cscov - Parts of the packet that are covered by the Checksum field
+ * @dccph_checksum - Internet checksum, depends on dccph_cscov
+ * @dccph_x - 0 = 24 bit sequence number, 1 = 48
+ * @dccph_type - packet type, see DCCP_PKT_ prefixed macros
+ * @dccph_seq - sequence number high or low order 24 bits, depends on dccph_x
+ */
+struct dccp_hdr {
+	__u16	dccph_sport,
+		dccph_dport;
+	__u8	dccph_doff;
+#if defined(__LITTLE_ENDIAN_BITFIELD)
+	__u8	dccph_cscov:4,
+		dccph_ccval:4;
+#elif defined(__BIG_ENDIAN_BITFIELD)
+	__u8	dccph_ccval:4,
+		dccph_cscov:4;
+#else
+#error  "Adjust your <asm/byteorder.h> defines"
+#endif
+	__u16	dccph_checksum;
+#if defined(__LITTLE_ENDIAN_BITFIELD)
+	__u32	dccph_x:1,
+		dccph_type:4,
+		dccph_reserved:3,
+		dccph_seq:24;
+#elif defined(__BIG_ENDIAN_BITFIELD)
+	__u32	dccph_reserved:3,
+		dccph_type:4,
+		dccph_x:1,
+		dccph_seq:24;
+#else
+#error  "Adjust your <asm/byteorder.h> defines"
+#endif
+};
+
+static inline struct dccp_hdr *dccp_hdr(const struct sk_buff *skb)
+{
+	return (struct dccp_hdr *)skb->h.raw;
+}
+
+/**
+ * struct dccp_hdr_ext - the low bits of a 48 bit seq packet
+ *
+ * @dccph_seq_low - low 24 bits of a 48 bit seq packet
+ */
+struct dccp_hdr_ext {
+	__u32	dccph_seq_low;
+};
+
+static inline struct dccp_hdr_ext *dccp_hdrx(const struct sk_buff *skb)
+{
+	return (struct dccp_hdr_ext *)(skb->h.raw + sizeof(struct dccp_hdr));
+}
+
+static inline unsigned int dccp_basic_hdr_len(const struct sk_buff *skb)
+{
+	const struct dccp_hdr *dh = dccp_hdr(skb);
+	return sizeof(*dh) + (dh->dccph_x ? sizeof(struct dccp_hdr_ext) : 0);
+}
+
+static inline __u64 dccp_hdr_seq(const struct sk_buff *skb)
+{
+	const struct dccp_hdr *dh = dccp_hdr(skb);
+#if defined(__LITTLE_ENDIAN_BITFIELD)
+	__u64 seq_nr = ntohl(dh->dccph_seq << 8);
+#elif defined(__BIG_ENDIAN_BITFIELD)
+	__u64 seq_nr = ntohl(dh->dccph_seq);
+#else
+#error  "Adjust your <asm/byteorder.h> defines"
+#endif
+
+	if (dh->dccph_x != 0)
+		seq_nr = (seq_nr << 32) + ntohl(dccp_hdrx(skb)->dccph_seq_low);
+
+	return seq_nr;
+}
+
+/**
+ * struct dccp_hdr_request - Conection initiation request header
+ *
+ * @dccph_req_service - Service to which the client app wants to connect
+ * @dccph_req_options - list of options (must be a multiple of 32 bits
+ */
+struct dccp_hdr_request {
+	__u32	dccph_req_service;
+};
+
+static inline struct dccp_hdr_request *dccp_hdr_request(struct sk_buff *skb)
+{
+	return (struct dccp_hdr_request *)(skb->h.raw + dccp_basic_hdr_len(skb));
+}
+
+/**
+ * struct dccp_hdr_ack_bits - acknowledgment bits common to most packets
+ *
+ * @dccph_resp_ack_nr_high - 48 bit ack number high order bits, contains GSR
+ * @dccph_resp_ack_nr_low - 48 bit ack number low order bits, contains GSR
+ */
+struct dccp_hdr_ack_bits {
+	__u32	dccph_reserved1:8,
+		dccph_ack_nr_high:24;
+	__u32	dccph_ack_nr_low;
+};
+
+static inline struct dccp_hdr_ack_bits *dccp_hdr_ack_bits(const struct sk_buff *skb)
+{
+	return (struct dccp_hdr_ack_bits *)(skb->h.raw + dccp_basic_hdr_len(skb));
+}
+
+static inline u64 dccp_hdr_ack_seq(const struct sk_buff *skb)
+{
+	const struct dccp_hdr_ack_bits *dhack = dccp_hdr_ack_bits(skb);
+#if defined(__LITTLE_ENDIAN_BITFIELD)
+	return (((u64)ntohl(dhack->dccph_ack_nr_high << 8)) << 32) + ntohl(dhack->dccph_ack_nr_low);
+#elif defined(__BIG_ENDIAN_BITFIELD)
+	return (((u64)ntohl(dhack->dccph_ack_nr_high)) << 32) + ntohl(dhack->dccph_ack_nr_low);
+#else
+#error  "Adjust your <asm/byteorder.h> defines"
+#endif
+}
+
+/**
+ * struct dccp_hdr_response - Conection initiation response header
+ *
+ * @dccph_resp_ack_nr_high - 48 bit ack number high order bits, contains GSR
+ * @dccph_resp_ack_nr_low - 48 bit ack number low order bits, contains GSR
+ * @dccph_resp_service - Echoes the Service Code on a received DCCP-Request
+ * @dccph_resp_options - list of options (must be a multiple of 32 bits
+ */
+struct dccp_hdr_response {
+	struct dccp_hdr_ack_bits	dccph_resp_ack;
+	__u32				dccph_resp_service;
+};
+
+static inline struct dccp_hdr_response *dccp_hdr_response(struct sk_buff *skb)
+{
+	return (struct dccp_hdr_response *)(skb->h.raw + dccp_basic_hdr_len(skb));
+}
+
+/**
+ * struct dccp_hdr_reset - Unconditionally shut down a connection
+ *
+ * @dccph_reset_service - Echoes the Service Code on a received DCCP-Request
+ * @dccph_reset_options - list of options (must be a multiple of 32 bits
+ */
+struct dccp_hdr_reset {
+	struct dccp_hdr_ack_bits	dccph_reset_ack;
+	__u8				dccph_reset_code,
+					dccph_reset_data[3];
+};
+
+static inline struct dccp_hdr_reset *dccp_hdr_reset(struct sk_buff *skb)
+{
+	return (struct dccp_hdr_reset *)(skb->h.raw + dccp_basic_hdr_len(skb));
+}
+
+enum dccp_pkt_type {
+	DCCP_PKT_REQUEST = 0,
+	DCCP_PKT_RESPONSE,
+	DCCP_PKT_DATA,
+	DCCP_PKT_ACK,
+	DCCP_PKT_DATAACK,
+	DCCP_PKT_CLOSEREQ,
+	DCCP_PKT_CLOSE,
+	DCCP_PKT_RESET,
+	DCCP_PKT_SYNC,
+	DCCP_PKT_SYNCACK,
+	DCCP_PKT_INVALID,
+};
+
+#define DCCP_NR_PKT_TYPES DCCP_PKT_INVALID
+
+static inline unsigned int dccp_packet_hdr_len(const __u8 type)
+{
+	if (type == DCCP_PKT_DATA)
+		return 0;
+	if (type == DCCP_PKT_DATAACK	||
+	    type == DCCP_PKT_ACK	||
+	    type == DCCP_PKT_SYNC	||
+	    type == DCCP_PKT_SYNCACK	||
+	    type == DCCP_PKT_CLOSE	||
+	    type == DCCP_PKT_CLOSEREQ)
+		return sizeof(struct dccp_hdr_ack_bits);
+	if (type == DCCP_PKT_REQUEST)
+		return sizeof(struct dccp_hdr_request);
+	if (type == DCCP_PKT_RESPONSE)
+		return sizeof(struct dccp_hdr_response);
+	return sizeof(struct dccp_hdr_reset);
+}
+
+static inline unsigned int dccp_hdr_len(const struct sk_buff *skb)
+{
+	return dccp_basic_hdr_len(skb) +
+	       dccp_packet_hdr_len(dccp_hdr(skb)->dccph_type);
+}
+
+enum dccp_reset_codes {
+	DCCP_RESET_CODE_UNSPECIFIED = 0,
+	DCCP_RESET_CODE_CLOSED,
+	DCCP_RESET_CODE_ABORTED,
+	DCCP_RESET_CODE_NO_CONNECTION,
+	DCCP_RESET_CODE_PACKET_ERROR,
+	DCCP_RESET_CODE_OPTION_ERROR,
+	DCCP_RESET_CODE_MANDATORY_ERROR,
+	DCCP_RESET_CODE_CONNECTION_REFUSED,
+	DCCP_RESET_CODE_BAD_SERVICE_CODE,
+	DCCP_RESET_CODE_TOO_BUSY,
+	DCCP_RESET_CODE_BAD_INIT_COOKIE,
+	DCCP_RESET_CODE_AGGRESSION_PENALTY,
+};
+
+/* DCCP options */
+enum {
+	DCCPO_PADDING = 0,
+	DCCPO_MANDATORY = 1,
+	DCCPO_MIN_RESERVED = 3,
+	DCCPO_MAX_RESERVED = 31,
+	DCCPO_NDP_COUNT = 37,
+	DCCPO_ACK_VECTOR_0 = 38,
+	DCCPO_ACK_VECTOR_1 = 39,
+	DCCPO_TIMESTAMP = 41,
+	DCCPO_TIMESTAMP_ECHO = 42,
+	DCCPO_ELAPSED_TIME = 43,
+	DCCPO_MAX = 45,
+	DCCPO_MIN_CCID_SPECIFIC = 128,
+	DCCPO_MAX_CCID_SPECIFIC = 255,
+};
+
+/* DCCP features */
+enum {
+	DCCPF_RESERVED = 0,
+	DCCPF_SEQUENCE_WINDOW = 3,
+	DCCPF_SEND_ACK_VECTOR = 6,
+	DCCPF_SEND_NDP_COUNT = 7,
+	/* 10-127 reserved */
+	DCCPF_MIN_CCID_SPECIFIC = 128,
+	DCCPF_MAX_CCID_SPECIFIC = 255,
+};
+
+/* initial values for each feature */
+#define DCCPF_INITIAL_SEQUENCE_WINDOW		100
+/* FIXME: for now we're using CCID 3 (TFRC) */
+#define DCCPF_INITIAL_CCID			3
+#define DCCPF_INITIAL_SEND_ACK_VECTOR		0
+/* FIXME: for now we're default to 1 but it should really be 0 */
+#define DCCPF_INITIAL_SEND_NDP_COUNT		1
+
+#define DCCP_NDP_LIMIT 0xFFFFFF
+
+/**
+  * struct dccp_options - option values for a DCCP connection
+  *	@dccpo_sequence_window - Sequence Window Feature (section 7.5.2)
+  *	@dccpo_ccid - Congestion Control Id (CCID) (section 10)
+  *	@dccpo_send_ack_vector - Send Ack Vector Feature (section 11.5)
+  *	@dccpo_send_ndp_count - Send NDP Count Feature (7.7.2)
+  */
+struct dccp_options {
+	__u64	dccpo_sequence_window;
+	__u8	dccpo_ccid;
+	__u8	dccpo_send_ack_vector;
+	__u8	dccpo_send_ndp_count;
+};
+
+extern void __dccp_options_init(struct dccp_options *dccpo);
+extern void dccp_options_init(struct dccp_options *dccpo);
+extern int dccp_parse_options(struct sock *sk, struct sk_buff *skb);
+
+struct dccp_request_sock {
+	struct inet_request_sock dreq_inet_rsk;
+	__u64			 dreq_iss;
+	__u64			 dreq_isr;
+	__u32			 dreq_service;
+};
+
+static inline struct dccp_request_sock *dccp_rsk(const struct request_sock *req)
+{
+	return (struct dccp_request_sock *)req;
+}
+
+/* Read about the ECN nonce to see why it is 253 */
+#define DCCP_MAX_ACK_VECTOR_LEN 253
+
+struct dccp_options_received {
+	u32	dccpor_ndp:24,
+		dccpor_ack_vector_len:8;
+	u32	dccpor_ack_vector_idx:10;
+	/* 22 bits hole, try to pack */
+	u32	dccpor_timestamp;
+	u32	dccpor_timestamp_echo;
+	u32	dccpor_elapsed_time;
+};
+
+struct ccid;
+
+enum dccp_role {
+	DCCP_ROLE_UNDEFINED,
+	DCCP_ROLE_LISTEN,
+	DCCP_ROLE_CLIENT,
+	DCCP_ROLE_SERVER,
+};
+
+/**
+ * struct dccp_sock - DCCP socket state
+ *
+ * @dccps_swl - sequence number window low
+ * @dccps_swh - sequence number window high
+ * @dccps_awl - acknowledgement number window low
+ * @dccps_awh - acknowledgement number window high
+ * @dccps_iss - initial sequence number sent
+ * @dccps_isr - initial sequence number received
+ * @dccps_osr - first OPEN sequence number received
+ * @dccps_gss - greatest sequence number sent
+ * @dccps_gsr - greatest valid sequence number received
+ * @dccps_gar - greatest valid ack number received on a non-Sync; initialized to %dccps_iss
+ * @dccps_timestamp_time - time of latest TIMESTAMP option
+ * @dccps_timestamp_echo - latest timestamp received on a TIMESTAMP option
+ * @dccps_ext_header_len - network protocol overhead (IP/IPv6 options)
+ * @dccps_pmtu_cookie - Last pmtu seen by socket
+ * @dccps_avg_packet_size - FIXME: has to be set by the app thru some setsockopt or ioctl, CCID3 uses it
+ * @dccps_role - Role of this sock, one of %dccp_role
+ * @dccps_ndp_count - number of Non Data Packets since last data packet
+ * @dccps_hc_rx_ackpkts - receiver half connection acked packets
+ */
+struct dccp_sock {
+	/* inet_connection_sock has to be the first member of dccp_sock */
+	struct inet_connection_sock	dccps_inet_connection;
+	__u64				dccps_swl;
+	__u64				dccps_swh;
+	__u64				dccps_awl;
+	__u64				dccps_awh;
+	__u64				dccps_iss;
+	__u64				dccps_isr;
+	__u64				dccps_osr;
+	__u64				dccps_gss;
+	__u64				dccps_gsr;
+	__u64				dccps_gar;
+	unsigned long			dccps_service;
+	unsigned long			dccps_timestamp_time;
+	__u32				dccps_timestamp_echo;
+	__u32				dccps_avg_packet_size;
+	unsigned long			dccps_ndp_count;
+	__u16				dccps_ext_header_len;
+	__u32				dccps_pmtu_cookie;
+	__u32				dccps_mss_cache;
+	struct dccp_options		dccps_options;
+	struct dccp_ackpkts		*dccps_hc_rx_ackpkts;
+	void				*dccps_hc_rx_ccid_private;
+	void				*dccps_hc_tx_ccid_private;
+	struct ccid			*dccps_hc_rx_ccid;
+	struct ccid			*dccps_hc_tx_ccid;
+	struct dccp_options_received	dccps_options_received;
+	enum dccp_role			dccps_role:2;
+};
+ 
+static inline struct dccp_sock *dccp_sk(const struct sock *sk)
+{
+	return (struct dccp_sock *)sk;
+}
+
+static inline const char *dccp_role(const struct sock *sk)
+{
+	switch (dccp_sk(sk)->dccps_role) {
+	case DCCP_ROLE_UNDEFINED: return "undefined";
+	case DCCP_ROLE_LISTEN:	  return "listen";
+	case DCCP_ROLE_SERVER:	  return "server";
+	case DCCP_ROLE_CLIENT:	  return "client";
+	}
+	return NULL;
+}
+
+#endif /* _LINUX_DCCP_H */
diff --git a/include/linux/in.h b/include/linux/in.h
index fb88c66d748..ba355384016 100644
--- a/include/linux/in.h
+++ b/include/linux/in.h
@@ -32,6 +32,7 @@ enum {
   IPPROTO_PUP = 12,		/* PUP protocol				*/
   IPPROTO_UDP = 17,		/* User Datagram Protocol		*/
   IPPROTO_IDP = 22,		/* XNS IDP protocol			*/
+  IPPROTO_DCCP = 33,		/* Datagram Congestion Control Protocol */
   IPPROTO_RSVP = 46,		/* RSVP protocol			*/
   IPPROTO_GRE = 47,		/* Cisco GRE tunnels (rfc 1701,1702)	*/
 
diff --git a/include/linux/net.h b/include/linux/net.h
index 39906619b9d..5f8b632ff65 100644
--- a/include/linux/net.h
+++ b/include/linux/net.h
@@ -84,6 +84,7 @@ enum sock_type {
 	SOCK_RAW	= 3,
 	SOCK_RDM	= 4,
 	SOCK_SEQPACKET	= 5,
+	SOCK_DCCP	= 6,
 	SOCK_PACKET	= 10,
 };
 
diff --git a/include/linux/socket.h b/include/linux/socket.h
index a5c7d96e4d2..ddf22559f48 100644
--- a/include/linux/socket.h
+++ b/include/linux/socket.h
@@ -271,6 +271,7 @@ struct ucred {
 #define SOL_IRDA        266
 #define SOL_NETBEUI	267
 #define SOL_LLC		268
+#define SOL_DCCP	269
 
 /* IPX options */
 #define IPX_TYPE	1