[NET]: Introduce inet_connection_sock

This creates struct inet_connection_sock, moving members out of struct
tcp_sock that are shareable with other INET connection oriented
protocols, such as DCCP, that in my private tree already uses most of
these members.

The functions that operate on these members were renamed, using a
inet_csk_ prefix while not being moved yet to a new file, so as to
ease the review of these changes.

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

include/linux/ip.h

@@ -128,7 +128,6 @@ static inline struct inet_request_sock *inet_rsk(const struct request_sock *sk)
 	return (struct inet_request_sock *)sk;
 }
 
-struct inet_bind_bucket;
 struct ipv6_pinfo;
 
 struct inet_sock {
@@ -158,7 +157,6 @@ struct inet_sock {
 	int			mc_index;	/* Multicast device index */
 	__u32			mc_addr;
 	struct ip_mc_socklist	*mc_list;	/* Group array */
-	struct inet_bind_bucket *bind_hash;
 	/*
 	 * Following members are used to retain the infomation to build
 	 * an ip header on each ip fragmentation while the socket is corked.

include/linux/ipv6.h

@@ -333,15 +333,15 @@ static inline struct in6_addr *tcp_v6_rcv_saddr(const struct sock *sk)
 	return sk->sk_family == AF_INET6 ? __tcp_v6_rcv_saddr(sk) : NULL;
 }
 
-static inline int tcp_twsk_ipv6only(const struct sock *sk)
+static inline int inet_twsk_ipv6only(const struct sock *sk)
 {
 	return inet_twsk(sk)->tw_ipv6only;
 }
 
-static inline int tcp_v6_ipv6only(const struct sock *sk)
+static inline int inet_v6_ipv6only(const struct sock *sk)
 {
 	return likely(sk->sk_state != TCP_TIME_WAIT) ?
-		ipv6_only_sock(sk) : tcp_twsk_ipv6only(sk);
+		ipv6_only_sock(sk) : inet_twsk_ipv6only(sk);
 }
 #else
 #define __ipv6_only_sock(sk)	0
@@ -360,7 +360,7 @@ static inline struct raw6_sock *raw6_sk(const struct sock *sk)
 #define __tcp_v6_rcv_saddr(__sk)	NULL
 #define tcp_v6_rcv_saddr(__sk)		NULL
 #define tcp_twsk_ipv6only(__sk)		0
-#define tcp_v6_ipv6only(__sk)		0
+#define inet_v6_ipv6only(__sk)		0
 #endif /* defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) */
 
 #define INET6_MATCH(__sk, __saddr, __daddr, __ports, __dif)	   \

include/linux/tcp.h

@@ -177,8 +177,8 @@ struct tcp_info
 
 #include <linux/config.h>
 #include <linux/skbuff.h>
-#include <linux/ip.h>
 #include <net/sock.h>
+#include <net/inet_connection_sock.h>
 #include <net/inet_timewait_sock.h>
 
 /* This defines a selective acknowledgement block. */
@@ -219,8 +219,8 @@ static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req)
 }
 
 struct tcp_sock {
-	/* inet_sock has to be the first member of tcp_sock */
-	struct inet_sock	inet;
+	/* inet_connection_sock has to be the first member of tcp_sock */
+	struct inet_connection_sock	inet_conn;
 	int	tcp_header_len;	/* Bytes of tcp header to send		*/
 
 /*
@@ -241,18 +241,6 @@ struct tcp_sock {
  	__u32	snd_sml;	/* Last byte of the most recently transmitted small packet */
 	__u32	rcv_tstamp;	/* timestamp of last received ACK (for keepalives) */
 	__u32	lsndtime;	/* timestamp of last sent data packet (for restart window) */
-	/* Delayed ACK control data */
-	struct {
-		__u8	pending;	/* ACK is pending */
-		__u8	quick;		/* Scheduled number of quick acks	*/
-		__u8	pingpong;	/* The session is interactive		*/
-		__u8	blocked;	/* Delayed ACK was blocked by socket lock*/
-		__u32	ato;		/* Predicted tick of soft clock		*/
-		unsigned long timeout;	/* Currently scheduled timeout		*/
-		__u32	lrcvtime;	/* timestamp of last received data packet*/
-		__u16	last_seg_size;	/* Size of last incoming segment	*/
-		__u16	rcv_mss;	/* MSS used for delayed ACK decisions	*/ 
-	} ack;
 
 	/* Data for direct copy to user */
 	struct {
@@ -271,8 +259,8 @@ struct tcp_sock {
 	__u16	xmit_size_goal;	/* Goal for segmenting output packets	*/
 	__u16	ext_header_len;	/* Network protocol overhead (IP/IPv6 options) */
 	__u8	ca_state;	/* State of fast-retransmit machine 	*/
-	__u8	retransmits;	/* Number of unrecovered RTO timeouts.	*/
 
+	__u8	keepalive_probes; /* num of allowed keep alive probes	*/
 	__u16	advmss;		/* Advertised MSS			*/
 	__u32	window_clamp;	/* Maximal window to advertise		*/
 	__u32	rcv_ssthresh;	/* Current window clamp			*/
@@ -281,7 +269,7 @@ struct tcp_sock {
 	__u8	reordering;	/* Packet reordering metric.		*/
 	__u8	frto_counter;	/* Number of new acks after RTO */
 
-	__u8	unused;
+	__u8	nonagle;	/* Disable Nagle algorithm?             */
 	__u8	defer_accept;	/* User waits for some data after accept() */
 
 /* RTT measurement */
@@ -290,19 +278,13 @@ struct tcp_sock {
 	__u32	mdev_max;	/* maximal mdev for the last rtt period	*/
 	__u32	rttvar;		/* smoothed mdev_max			*/
 	__u32	rtt_seq;	/* sequence number to update rttvar	*/
-	__u32	rto;		/* retransmit timeout			*/
 
 	__u32	packets_out;	/* Packets which are "in flight"	*/
 	__u32	left_out;	/* Packets which leaved network	*/
 	__u32	retrans_out;	/* Retransmitted packets out		*/
-	__u8	backoff;	/* backoff				*/
 /*
  *      Options received (usually on last packet, some only on SYN packets).
  */
-	__u8	nonagle;	/* Disable Nagle algorithm?             */
-	__u8	keepalive_probes; /* num of allowed keep alive probes	*/
-
-	__u8	probes_out;	/* unanswered 0 window probes		*/
 	struct tcp_options_received rx_opt;
 
 /*
@@ -315,11 +297,6 @@ struct tcp_sock {
 	__u32	snd_cwnd_used;
 	__u32	snd_cwnd_stamp;
 
-	/* Two commonly used timers in both sender and receiver paths. */
-	unsigned long		timeout;
- 	struct timer_list	retransmit_timer;	/* Resend (no ack)	*/
- 	struct timer_list	delack_timer;		/* Ack delay 		*/
-
 	struct sk_buff_head	out_of_order_queue; /* Out of order segments go here */
 
 	struct tcp_func		*af_specific;	/* Operations which are AF_INET{4,6} specific	*/
@@ -334,7 +311,7 @@ struct tcp_sock {
 	struct tcp_sack_block duplicate_sack[1]; /* D-SACK block */
 	struct tcp_sack_block selective_acks[4]; /* The SACKS themselves*/
 
-	__u8	syn_retries;	/* num of allowed syn retries */
+	__u8	probes_out;	/* unanswered 0 window probes		*/
 	__u8	ecn_flags;	/* ECN status bits.			*/
 	__u16	prior_ssthresh; /* ssthresh saved at recovery start	*/
 	__u32	lost_out;	/* Lost packets			*/
@@ -349,14 +326,12 @@ struct tcp_sock {
 	int	undo_retrans;	/* number of undoable retransmissions. */
 	__u32	urg_seq;	/* Seq of received urgent pointer */
 	__u16	urg_data;	/* Saved octet of OOB data and control flags */
-	__u8	pending;	/* Scheduled timer event	*/
 	__u8	urg_mode;	/* In urgent mode		*/
+	/* ONE BYTE HOLE, TRY TO PACK! */
 	__u32	snd_up;		/* Urgent pointer		*/
 
 	__u32	total_retrans;	/* Total retransmits for entire connection */
 
-	struct request_sock_queue accept_queue; /* FIFO of established children */
-
 	unsigned int		keepalive_time;	  /* time before keep alive takes place */
 	unsigned int		keepalive_intvl;  /* time interval between keep alive probes */
 	int			linger2;

include/net/inet_connection_sock.h

@@ -0,0 +1,86 @@
+/*
+ * NET		Generic infrastructure for INET connection oriented protocols.
+ *
+ *		Definitions for inet_connection_sock 
+ *
+ * Authors:	Many people, see the TCP sources
+ *
+ * 		From code originally in TCP
+ *
+ *		This program is free software; you can redistribute it and/or
+ *		modify it under the terms of the GNU General Public License
+ *		as published by the Free Software Foundation; either version
+ *		2 of the License, or (at your option) any later version.
+ */
+#ifndef _INET_CONNECTION_SOCK_H
+#define _INET_CONNECTION_SOCK_H
+
+#include <linux/ip.h>
+#include <linux/timer.h>
+#include <net/request_sock.h>
+
+struct inet_bind_bucket;
+struct inet_hashinfo;
+
+/** inet_connection_sock - INET connection oriented sock
+ *
+ * @icsk_accept_queue:	   FIFO of established children 
+ * @icsk_bind_hash:	   Bind node
+ * @icsk_timeout:	   Timeout
+ * @icsk_retransmit_timer: Resend (no ack)
+ * @icsk_rto:		   Retransmit timeout
+ * @icsk_retransmits:	   Number of unrecovered [RTO] timeouts
+ * @icsk_pending:	   Scheduled timer event
+ * @icsk_backoff:	   Backoff
+ * @icsk_syn_retries:      Number of allowed SYN (or equivalent) retries
+ * @icsk_ack:		   Delayed ACK control data
+ */
+struct inet_connection_sock {
+	/* inet_sock has to be the first member! */
+	struct inet_sock	  icsk_inet;
+	struct request_sock_queue icsk_accept_queue;
+	struct inet_bind_bucket	  *icsk_bind_hash;
+	unsigned long		  icsk_timeout;
+ 	struct timer_list	  icsk_retransmit_timer;
+ 	struct timer_list	  icsk_delack_timer;
+	__u32			  icsk_rto;
+	__u8			  icsk_retransmits;
+	__u8			  icsk_pending;
+	__u8			  icsk_backoff;
+	__u8			  icsk_syn_retries;
+	struct {
+		__u8		  pending;	 /* ACK is pending			   */
+		__u8		  quick;	 /* Scheduled number of quick acks	   */
+		__u8		  pingpong;	 /* The session is interactive		   */
+		__u8		  blocked;	 /* Delayed ACK was blocked by socket lock */
+		__u32		  ato;		 /* Predicted tick of soft clock	   */
+		unsigned long	  timeout;	 /* Currently scheduled timeout		   */
+		__u32		  lrcvtime;	 /* timestamp of last received data packet */
+		__u16		  last_seg_size; /* Size of last incoming segment	   */
+		__u16		  rcv_mss;	 /* MSS used for delayed ACK decisions	   */ 
+	} icsk_ack;
+};
+
+static inline struct inet_connection_sock *inet_csk(const struct sock *sk)
+{
+	return (struct inet_connection_sock *)sk;
+}
+
+extern void inet_csk_init_xmit_timers(struct sock *sk,
+				      void (*retransmit_handler)(unsigned long),
+				      void (*delack_handler)(unsigned long),
+				      void (*keepalive_handler)(unsigned long));
+extern void inet_csk_clear_xmit_timers(struct sock *sk);
+
+extern struct request_sock *inet_csk_search_req(const struct sock *sk,
+						struct request_sock ***prevp,
+						const __u16 rport,
+						const __u32 raddr,
+						const __u32 laddr);
+extern int inet_csk_get_port(struct inet_hashinfo *hashinfo,
+			     struct sock *sk, unsigned short snum);
+
+extern struct dst_entry* inet_csk_route_req(struct sock *sk,
+					    const struct request_sock *req);
+
+#endif /* _INET_CONNECTION_SOCK_H */

include/net/inet_hashtables.h

@@ -17,7 +17,6 @@
 #include <linux/config.h>
 
 #include <linux/interrupt.h>
-#include <linux/ip.h>
 #include <linux/ipv6.h>
 #include <linux/list.h>
 #include <linux/slab.h>
@@ -26,6 +25,7 @@
 #include <linux/types.h>
 #include <linux/wait.h>
 
+#include <net/inet_connection_sock.h>
 #include <net/sock.h>
 #include <net/tcp_states.h>
 
@@ -185,9 +185,9 @@ static inline void __inet_inherit_port(struct inet_hashinfo *table,
 	struct inet_bind_bucket *tb;
 
 	spin_lock(&head->lock);
-	tb = inet_sk(sk)->bind_hash;
+	tb = inet_csk(sk)->icsk_bind_hash;
 	sk_add_bind_node(child, &tb->owners);
-	inet_sk(child)->bind_hash = tb;
+	inet_csk(child)->icsk_bind_hash = tb;
 	spin_unlock(&head->lock);
 }
 

include/net/request_sock.h

@@ -224,17 +224,17 @@ static inline int reqsk_queue_added(struct request_sock_queue *queue)
 	return prev_qlen;
 }
 
-static inline int reqsk_queue_len(struct request_sock_queue *queue)
+static inline int reqsk_queue_len(const struct request_sock_queue *queue)
 {
 	return queue->listen_opt != NULL ? queue->listen_opt->qlen : 0;
 }
 
-static inline int reqsk_queue_len_young(struct request_sock_queue *queue)
+static inline int reqsk_queue_len_young(const struct request_sock_queue *queue)
 {
 	return queue->listen_opt->qlen_young;
 }
 
-static inline int reqsk_queue_is_full(struct request_sock_queue *queue)
+static inline int reqsk_queue_is_full(const struct request_sock_queue *queue)
 {
 	return queue->listen_opt->qlen >> queue->listen_opt->max_qlen_log;
 }

include/net/sock.h

@@ -493,9 +493,6 @@ extern int sk_wait_data(struct sock *sk, long *timeo);
 
 struct request_sock_ops;
 
-/* Here is the right place to enable sock refcounting debugging */
-//#define SOCK_REFCNT_DEBUG
-
 /* Networking protocol blocks we attach to sockets.
  * socket layer -> transport layer interface
  * transport -> network interface is defined by struct inet_proto