[PATCH net-next 03/15] net: bus: Add AF_BUS socket and address definitions

[Vincent Sanders <vincent.sanders@xxxxxxxxxxxxxxx>]

From: Javier Martinez Canillas <javier.martinez@xxxxxxxxxxxxxxx>

An AF_BUS socket address is made up of a path component and a numeric
component. The path component is either a pathname or an abstract
socket similar to a unix socket. The numeric component is used to
uniquely identify each connection to the bus. Thus the path identifies
a specific bus and the numeric component the attachment to that bus.

The numeric component of the address is a 64-bit unsigned integer,
interpreted by splitting the into two parts: the most significant 16
bits are a prefix identifying the type of address, and the remaining
48 bits are the actual client address within that prefix, as shown in
this figure:

Bit:  0             15 16                                            63
     +----------------+------------------------------------------------+
     |  Type prefix   |                Client address                  |
     +----------------+------------------------------------------------+

Signed-off-by: Javier Martinez Canillas <javier.martinez@xxxxxxxxxxxxxxx>
Signed-off-by: Vincent Sanders <vincent.sanders@xxxxxxxxxxxxxxx>
---
 include/linux/bus.h  |   34 +++++++
 include/net/af_bus.h |  272 ++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 306 insertions(+)
 create mode 100644 include/linux/bus.h
 create mode 100644 include/net/af_bus.h

diff --git a/include/linux/bus.h b/include/linux/bus.h
new file mode 100644
index 0000000..19cac36
--- /dev/null
+++ b/include/linux/bus.h
@@ -0,0 +1,34 @@
+#ifndef _LINUX_BUS_H
+#define _LINUX_BUS_H
+
+#include <linux/socket.h>
+
+/* 'protocol' to use in socket(AF_BUS, SOCK_SEQPACKET, protocol) */
+#define BUS_PROTO_NONE	0
+#define BUS_PROTO_DBUS	1
+#define BUS_PROTO_MAX	1
+
+#define BUS_PATH_MAX	108
+
+/**
+ * struct bus_addr - af_bus address
+ * @s_addr: an af_bus address (16-bit prefix + 48-bit client address)
+ */
+struct bus_addr {
+	u64 s_addr;
+};
+
+
+/**
+ * struct sockaddr_bus - af_bus socket address
+ * @sbus_family: the socket address family
+ * @sbus_addr: an af_bus address
+ * @sbus_path: a path name
+ */
+struct sockaddr_bus {
+	__kernel_sa_family_t sbus_family;
+	struct bus_addr      sbus_addr;
+	char sbus_path[BUS_PATH_MAX];
+};
+
+#endif /* _LINUX_BUS_H */
diff --git a/include/net/af_bus.h b/include/net/af_bus.h
new file mode 100644
index 0000000..19bd7ac
--- /dev/null
+++ b/include/net/af_bus.h
@@ -0,0 +1,272 @@
+/*
+ * Copyright (c) 2012, GENIVI Alliance
+ *
+ * Authors:	Javier Martinez Canillas, <javier.martinez@xxxxxxxxxxxxxxx>
+ *              Alban Crequy, <alban.crequy@xxxxxxxxxxxxxxx>
+ *
+ *		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.
+ *
+ * Based on BSD Unix domain sockets (net/unix).
+ */
+
+#ifndef __LINUX_NET_AFBUS_H
+#define __LINUX_NET_AFBUS_H
+
+#include <linux/socket.h>
+#include <linux/bus.h>
+#include <linux/mutex.h>
+#include <net/sock.h>
+#include <net/tcp_states.h>
+
+extern void bus_inflight(struct file *fp);
+extern void bus_notinflight(struct file *fp);
+extern void bus_gc(void);
+extern void wait_for_bus_gc(void);
+extern struct sock *bus_get_socket(struct file *filp);
+extern struct sock *bus_peer_get(struct sock *);
+
+#define BUS_HASH_SIZE	256
+
+extern spinlock_t bus_address_lock;
+extern struct hlist_head bus_address_table[BUS_HASH_SIZE];
+
+#define BUS_MAX_QLEN    10
+#define BUS_MASTER_ADDR 0x0
+#define BUS_PREFIX_BITS 16
+#define BUS_CLIENT_BITS 48
+#define BUS_PREFIX_MASK 0xffff000000000000
+#define BUS_CLIENT_MASK 0x0000ffffffffffff
+
+/* AF_BUS socket options */
+#define BUS_ADD_ADDR 1
+#define BUS_JOIN_BUS 2
+#define BUS_DEL_ADDR 3
+#define BUS_SET_EAVESDROP 4
+#define BUS_UNSET_EAVESDROP 5
+#define BUS_SET_SENDBUF 6
+#define BUS_SET_MAXQLEN 7
+
+/* Connection and socket states */
+enum {
+	BUS_ESTABLISHED = TCP_ESTABLISHED,
+	BUS_CLOSE = TCP_CLOSE,
+	BUS_LISTEN = TCP_LISTEN,
+	BUS_MAX_STATES
+};
+
+#define NF_BUS_SENDING 1
+
+extern unsigned int bus_tot_inflight;
+extern spinlock_t bus_table_lock;
+extern struct hlist_head bus_socket_table[BUS_HASH_SIZE + 1];
+
+/**
+ * struct bus_address - an af_bus address associated with an af_bus sock
+ * @refcnt: address reference counter
+ * @len: address length
+ * @hash: address hash value
+ * @addr_node: member of struct bus_sock.addr_list
+ * @table_node: member of struct hlist_head bus_address_table[hash]
+ * @sock: the af_bus sock that owns this address
+ * @name: the socket address for this address
+ */
+struct bus_address {
+	atomic_t	refcnt;
+	int		len;
+	unsigned	hash;
+	struct hlist_node addr_node;
+	struct hlist_node table_node;
+	struct sock  *sock;
+	struct sockaddr_bus name[0];
+};
+
+/**
+ * struct bus_send_context - sending context for an socket buffer
+ * @sender_socket: the sender socket associated with this sk_buff
+ * @siocb: used to send ancillary data
+ * @timeo: sending timeout
+ * @max_level: file descriptor passing maximum recursion level
+ * @namelen: length of socket address name
+ * @hash: socket name hash value
+ * @other: destination sock
+ * @sender: sender socket address name
+ * @recipient: recipient socket address name
+ * @authenticated: flag whether the sock already joined the bus
+ * @bus_master_side: flag whether the sock is an accepted socket
+ * @to_master: flag whether the destination is the bus master
+ * @multicast: flag whether the destination is a multicast address
+ * @deliver: flag whether the skb has to be delivered
+ * @eavesdropper: flag whether the sock is allowed to eavesdrop
+ * @main_recipient: flag whether the sock is the main recipient
+ */
+struct bus_send_context {
+	struct socket *sender_socket;
+	struct sock_iocb *siocb;
+	long timeo;
+	int max_level;
+	int namelen;
+	unsigned hash;
+	struct sock *other;
+	struct sockaddr_bus	*sender;
+	struct sockaddr_bus	*recipient;
+	unsigned int		authenticated:1;
+	unsigned int		bus_master_side:1;
+	unsigned int		to_master:1;
+	unsigned int		multicast:1;
+	unsigned int            deliver:1;
+	unsigned int            eavesdropper:1;
+	unsigned int            main_recipient:1;
+};
+
+/**
+ * struct bus_skb_parms - socket buffer parameters
+ * @pid: process id
+ * @cred: skb credentials
+ * @fp: passed file descriptors
+ * @secid: security id
+ * @sendctx: skb sending context
+ */
+struct bus_skb_parms {
+	struct pid		*pid;
+	const struct cred	*cred;
+	struct scm_fp_list	*fp;
+#ifdef CONFIG_SECURITY_NETWORK
+	u32			secid;
+#endif
+	struct bus_send_context	*sendctx;
+};
+
+#define BUSCB(skb)      (*(struct bus_skb_parms *)&((skb)->cb))
+#define BUSSID(skb)     (&BUSCB((skb)).secid)
+
+#define bus_state_lock(s)	spin_lock(&bus_sk(s)->lock)
+#define bus_state_unlock(s)	spin_unlock(&bus_sk(s)->lock)
+#define bus_state_lock_nested(s) \
+				spin_lock_nested(&bus_sk(s)->lock, \
+				SINGLE_DEPTH_NESTING)
+
+/**
+ * struct bus - a communication bus
+ * @master: the bus master sock
+ * @peers: list of struct bus_sock.bus_node allowed to join the bus
+ * @lock: protect peers concurrent access
+ * @send_lock: enforce atomic multicast delivery
+ * @kref: bus reference counter
+ * @addr_cnt: address number counter to assign prefix 0x0000 addresses
+ * @eavesdropper_cnt: eavesdroppers counter
+ */
+struct bus {
+	struct sock		*master;
+	struct hlist_head       peers;
+	spinlock_t		lock;
+	spinlock_t		send_lock;
+	struct kref             kref;
+	atomic64_t              addr_cnt;
+	atomic64_t              eavesdropper_cnt;
+};
+
+/**
+ * struct bus_sock - an af_bus socket
+ * @sk: associated sock
+ * @addr: sock principal address
+ * @addr_list: list of struct bus_address.addr_node
+ * @path: sock path name
+ * @readlock: protect from concurrent reading
+ * @peer: peer sock
+ * @other: the listening sock
+ * @link: list of candidates for garbage collection
+ * @inflight: number of times the file descriptor is in flight
+ * @lock: protect the sock from concurrent access
+ * @gc_candidate: flag whether the is a candidate for gc
+ * @gc_maybe_cycle: flag whether could be a cyclic reference
+ * @recursion_level: file passing current recursion level
+ * @peer_wq: peer sock wait queue
+ * @bus: bus that this sock belongs to
+ * @bus_master: flag whether the sock is the bus master
+ * @bus_master_side: flag whether is an accepted socket
+ * @authenticated: flag whether the sock joined the bus
+ * @eavesdropper: flag whether the sock is allowed to eavesdrop
+ * @bus_node: member of struct bus.peers list of joined socks
+ */
+struct bus_sock {
+	/* WARNING: sk has to be the first member */
+	struct sock		sk;
+	struct bus_address     *addr;
+	struct hlist_head       addr_list;
+	struct path		path;
+	struct mutex		readlock;
+	struct sock		*peer;
+	struct sock		*other;
+	struct list_head	link;
+	atomic_long_t		inflight;
+	spinlock_t		lock;
+	unsigned int		gc_candidate:1;
+	unsigned int		gc_maybe_cycle:1;
+	unsigned char		recursion_level;
+	struct socket_wq	peer_wq;
+	struct bus              *bus;
+	bool                    bus_master;
+	bool                    bus_master_side;
+	bool                    authenticated;
+	bool                    eavesdropper;
+	struct hlist_node	bus_node;
+};
+#define bus_sk(__sk) ((struct bus_sock *)__sk)
+
+#define peer_wait peer_wq.wait
+
+/**
+ * bus_same_bus - Test if two socket address belongs to the same bus
+ * @sbusaddr1: socket address name
+ * @sbusaddr2: socket address name
+ */
+static inline bool bus_same_bus(struct sockaddr_bus *sbusaddr1,
+				struct sockaddr_bus *sbusaddr2)
+{
+	int offset;
+
+	if (sbusaddr1->sbus_path[0] != sbusaddr2->sbus_path[0])
+		return false;
+
+	/*
+	 * abstract path names start with a null byte character,
+	 * so they have to be compared starting at the second char.
+	 */
+	offset = (sbusaddr1->sbus_path[0] == '\0');
+
+	return !strncmp(sbusaddr1->sbus_path + offset,
+		       sbusaddr2->sbus_path + offset,
+		       BUS_PATH_MAX);
+}
+
+static inline unsigned int bus_hash_fold(__wsum n)
+{
+	unsigned int hash = (__force unsigned int)n;
+	hash ^= hash>>16;
+	hash ^= hash>>8;
+	return hash&(BUS_HASH_SIZE-1);
+}
+
+static inline unsigned int bus_compute_hash(struct bus_addr addr)
+{
+	return bus_hash_fold(csum_partial((void *)&addr, sizeof(addr), 0));
+}
+
+long bus_inq_len(struct sock *sk);
+long bus_outq_len(struct sock *sk);
+
+#ifdef CONFIG_SYSCTL
+extern int bus_sysctl_register(struct net *net);
+extern void bus_sysctl_unregister(struct net *net);
+#else
+static inline int bus_sysctl_register(struct net *net) { return 0; }
+static inline void bus_sysctl_unregister(struct net *net) {}
+#endif
+
+bool bus_can_write(struct net *net, struct sockaddr_bus *addr, int len,
+		   int protocol);
+
+#endif /* __LINUX_NET_AFBUS_H */
-- 
1.7.10

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