From 7672d0b54411371e0b6a831c1cb2f0ce615de6dc Mon Sep 17 00:00:00 2001 From: Evgeniy Polyakov Date: Sun, 11 Sep 2005 19:15:07 -0700 Subject: [NET]: Add netlink connector. Kernel connector - new userspace <-> kernel space easy to use communication module which implements easy to use bidirectional message bus using netlink as it's backend. Connector was created to eliminate complex skb handling both in send and receive message bus direction. Connector driver adds possibility to connect various agents using as one of it's backends netlink based network. One must register callback and identifier. When driver receives special netlink message with appropriate identifier, appropriate callback will be called. From the userspace point of view it's quite straightforward: socket(); bind(); send(); recv(); But if kernelspace want to use full power of such connections, driver writer must create special sockets, must know about struct sk_buff handling... Connector allows any kernelspace agents to use netlink based networking for inter-process communication in a significantly easier way: int cn_add_callback(struct cb_id *id, char *name, void (*callback) (void *)); void cn_netlink_send(struct cn_msg *msg, u32 __groups, int gfp_mask); struct cb_id { __u32 idx; __u32 val; }; idx and val are unique identifiers which must be registered in connector.h for in-kernel usage. void (*callback) (void *) - is a callback function which will be called when message with above idx.val will be received by connector core. Using connector completely hides low-level transport layer from it's users. Connector uses new netlink ability to have many groups in one socket. [ Incorporating many cleanups and fixes by myself and Andrew Morton -DaveM ] Signed-off-by: Evgeniy Polyakov Signed-off-by: Andrew Morton Signed-off-by: David S. Miller --- include/linux/connector.h | 158 ++++++++++++++++++++++++++++++++++++++++++++++ include/linux/netlink.h | 1 + 2 files changed, 159 insertions(+) create mode 100644 include/linux/connector.h (limited to 'include/linux') diff --git a/include/linux/connector.h b/include/linux/connector.h new file mode 100644 index 000000000000..96de26301f84 --- /dev/null +++ b/include/linux/connector.h @@ -0,0 +1,158 @@ +/* + * connector.h + * + * 2004-2005 Copyright (c) Evgeniy Polyakov + * All rights reserved. + * + * 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. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#ifndef __CONNECTOR_H +#define __CONNECTOR_H + +#include + +#define CN_IDX_CONNECTOR 0xffffffff +#define CN_VAL_CONNECTOR 0xffffffff + +#define CN_NETLINK_USERS 1 + +/* + * Maximum connector's message size. + */ +#define CONNECTOR_MAX_MSG_SIZE 1024 + +/* + * idx and val are unique identifiers which + * are used for message routing and + * must be registered in connector.h for in-kernel usage. + */ + +struct cb_id { + __u32 idx; + __u32 val; +}; + +struct cn_msg { + struct cb_id id; + + __u32 seq; + __u32 ack; + + __u16 len; /* Length of the following data */ + __u16 flags; + __u8 data[0]; +}; + +/* + * Notify structure - requests notification about + * registering/unregistering idx/val in range [first, first+range]. + */ +struct cn_notify_req { + __u32 first; + __u32 range; +}; + +/* + * Main notification control message + * *_notify_num - number of appropriate cn_notify_req structures after + * this struct. + * group - notification receiver's idx. + * len - total length of the attached data. + */ +struct cn_ctl_msg { + __u32 idx_notify_num; + __u32 val_notify_num; + __u32 group; + __u32 len; + __u8 data[0]; +}; + +#ifdef __KERNEL__ + +#include + +#include +#include + +#include + +#define CN_CBQ_NAMELEN 32 + +struct cn_queue_dev { + atomic_t refcnt; + unsigned char name[CN_CBQ_NAMELEN]; + + struct workqueue_struct *cn_queue; + + struct list_head queue_list; + spinlock_t queue_lock; + + int netlink_groups; + struct sock *nls; +}; + +struct cn_callback { + unsigned char name[CN_CBQ_NAMELEN]; + + struct cb_id id; + void (*callback) (void *); + void *priv; +}; + +struct cn_callback_entry { + struct list_head callback_entry; + struct cn_callback *cb; + struct work_struct work; + struct cn_queue_dev *pdev; + + void (*destruct_data) (void *); + void *ddata; + + int seq, group; + struct sock *nls; +}; + +struct cn_ctl_entry { + struct list_head notify_entry; + struct cn_ctl_msg *msg; +}; + +struct cn_dev { + struct cb_id id; + + u32 seq, groups; + struct sock *nls; + void (*input) (struct sock * sk, int len); + + struct cn_queue_dev *cbdev; +}; + +int cn_add_callback(struct cb_id *, char *, void (*callback) (void *)); +void cn_del_callback(struct cb_id *); +int cn_netlink_send(struct cn_msg *, u32, int); + +int cn_queue_add_callback(struct cn_queue_dev *dev, struct cn_callback *cb); +void cn_queue_del_callback(struct cn_queue_dev *dev, struct cb_id *id); + +struct cn_queue_dev *cn_queue_alloc_dev(char *name, struct sock *); +void cn_queue_free_dev(struct cn_queue_dev *dev); + +int cn_cb_equal(struct cb_id *, struct cb_id *); + +extern int cn_already_initialized; + +#endif /* __KERNEL__ */ +#endif /* __CONNECTOR_H */ diff --git a/include/linux/netlink.h b/include/linux/netlink.h index 167518668936..7bbd25970c9e 100644 --- a/include/linux/netlink.h +++ b/include/linux/netlink.h @@ -15,6 +15,7 @@ #define NETLINK_ISCSI 8 /* Open-iSCSI */ #define NETLINK_AUDIT 9 /* auditing */ #define NETLINK_FIB_LOOKUP 10 +#define NETLINK_CONNECTOR 11 #define NETLINK_NETFILTER 12 /* netfilter subsystem */ #define NETLINK_IP6_FW 13 #define NETLINK_DNRTMSG 14 /* DECnet routing messages */ -- cgit From e21ce8c7c013fb223a002c70bb0a547de6c26c12 Mon Sep 17 00:00:00 2001 From: Ralf Baechle Date: Mon, 12 Sep 2005 14:27:37 -0700 Subject: [NETROM]: Implement G8PZT Circuit reset for NET/ROM NET/ROM is lacking a connection reset like TCP's RST flag which at times may result in a connecting having to slowly timing out instead of just being reset. An earlier attempt to reset the connection by sending a NR_CONNACK | NR_CHOKE_FLAG transport was inacceptable as it did result in crashes of BPQ systems. An alternative approach of introducing a new transport type 7 (NR_RESET) has be implemented several years ago in Paula Jayne Dowie G8PZT's Xrouter. Implement NR_RESET for Linux's NET/ROM but like any messing with the state engine consider this experimental for now and thus control it by a sysctl (net.netrom.reset) which for the time being defaults to off. Signed-off-by: Ralf Baechle DL5RB Signed-off-by: David S. Miller --- include/linux/sysctl.h | 3 ++- include/net/netrom.h | 27 ++++++++++++++++++++++++++- net/netrom/af_netrom.c | 21 +++++++++++---------- net/netrom/nr_in.c | 15 +++++++++++++++ net/netrom/nr_subr.c | 7 +++---- net/netrom/sysctl_net_netrom.c | 12 ++++++++++++ 6 files changed, 69 insertions(+), 16 deletions(-) (limited to 'include/linux') diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h index 532a6c5c24e9..3a29a9f9b451 100644 --- a/include/linux/sysctl.h +++ b/include/linux/sysctl.h @@ -544,7 +544,8 @@ enum { NET_NETROM_TRANSPORT_REQUESTED_WINDOW_SIZE=8, NET_NETROM_TRANSPORT_NO_ACTIVITY_TIMEOUT=9, NET_NETROM_ROUTING_CONTROL=10, - NET_NETROM_LINK_FAILS_COUNT=11 + NET_NETROM_LINK_FAILS_COUNT=11, + NET_NETROM_RESET=12 }; /* /proc/sys/net/ax25 */ diff --git a/include/net/netrom.h b/include/net/netrom.h index 45f2c7616d8b..ad05d7a3c55d 100644 --- a/include/net/netrom.h +++ b/include/net/netrom.h @@ -22,6 +22,7 @@ #define NR_DISCACK 0x04 #define NR_INFO 0x05 #define NR_INFOACK 0x06 +#define NR_RESET 0x07 #define NR_CHOKE_FLAG 0x80 #define NR_NAK_FLAG 0x40 @@ -51,6 +52,7 @@ enum { #define NR_DEFAULT_TTL 16 /* Default Time To Live - 16 */ #define NR_DEFAULT_ROUTING 1 /* Is routing enabled ? */ #define NR_DEFAULT_FAILS 2 /* Link fails until route fails */ +#define NR_DEFAULT_RESET 0 /* Sent / accept reset cmds? */ #define NR_MODULUS 256 #define NR_MAX_WINDOW_SIZE 127 /* Maximum Window Allowable - 127 */ @@ -176,6 +178,8 @@ extern int sysctl_netrom_transport_requested_window_size; extern int sysctl_netrom_transport_no_activity_timeout; extern int sysctl_netrom_routing_control; extern int sysctl_netrom_link_fails_count; +extern int sysctl_netrom_reset_circuit; + extern int nr_rx_frame(struct sk_buff *, struct net_device *); extern void nr_destroy_socket(struct sock *); @@ -218,7 +222,28 @@ extern void nr_requeue_frames(struct sock *); extern int nr_validate_nr(struct sock *, unsigned short); extern int nr_in_rx_window(struct sock *, unsigned short); extern void nr_write_internal(struct sock *, int); -extern void nr_transmit_refusal(struct sk_buff *, int); + +extern void __nr_transmit_reply(struct sk_buff *skb, int mine, + unsigned char cmdflags); + +/* + * This routine is called when a Connect Acknowledge with the Choke Flag + * set is needed to refuse a connection. + */ +#define nr_transmit_refusal(skb, mine) \ +do { \ + __nr_transmit_reply((skb), (mine), NR_CONNACK | NR_CHOKE_FLAG); \ +} while (0) + +/* + * This routine is called when we don't have a circuit matching an incoming + * NET/ROM packet. This is an G8PZT Xrouter extension. + */ +#define nr_transmit_reset(skb, mine) \ +do { \ + __nr_transmit_reply((skb), (mine), NR_RESET); \ +} while (0) + extern void nr_disconnect(struct sock *, int); /* nr_timer.c */ diff --git a/net/netrom/af_netrom.c b/net/netrom/af_netrom.c index 02b1ab52dbbf..8c3d3a78481e 100644 --- a/net/netrom/af_netrom.c +++ b/net/netrom/af_netrom.c @@ -56,6 +56,7 @@ int sysctl_netrom_transport_requested_window_size = NR_DEFAULT_WINDOW; int sysctl_netrom_transport_no_activity_timeout = NR_DEFAULT_IDLE; int sysctl_netrom_routing_control = NR_DEFAULT_ROUTING; int sysctl_netrom_link_fails_count = NR_DEFAULT_FAILS; +int sysctl_netrom_reset_circuit = NR_DEFAULT_RESET; static unsigned short circuit = 0x101; @@ -908,17 +909,17 @@ int nr_rx_frame(struct sk_buff *skb, struct net_device *dev) if (frametype != NR_CONNREQ) { /* * Here it would be nice to be able to send a reset but - * NET/ROM doesn't have one. The following hack would - * have been a way to extend the protocol but apparently - * it kills BPQ boxes... :-( + * NET/ROM doesn't have one. We've tried to extend the protocol + * by sending NR_CONNACK | NR_CHOKE_FLAGS replies but that + * apparently kills BPQ boxes... :-( + * So now we try to follow the established behaviour of + * G8PZT's Xrouter which is sending packets with command type 7 + * as an extension of the protocol. */ -#if 0 - /* - * Never reply to a CONNACK/CHOKE. - */ - if (frametype != NR_CONNACK || flags != NR_CHOKE_FLAG) - nr_transmit_refusal(skb, 1); -#endif + if (sysctl_netrom_reset_circuit && + (frametype != NR_RESET || flags != 0)) + nr_transmit_reset(skb, 1); + return 0; } diff --git a/net/netrom/nr_in.c b/net/netrom/nr_in.c index 64b81a796907..004e8599b8fe 100644 --- a/net/netrom/nr_in.c +++ b/net/netrom/nr_in.c @@ -98,6 +98,11 @@ static int nr_state1_machine(struct sock *sk, struct sk_buff *skb, nr_disconnect(sk, ECONNREFUSED); break; + case NR_RESET: + if (sysctl_netrom_reset_circuit); + nr_disconnect(sk, ECONNRESET); + break; + default: break; } @@ -124,6 +129,11 @@ static int nr_state2_machine(struct sock *sk, struct sk_buff *skb, nr_disconnect(sk, 0); break; + case NR_RESET: + if (sysctl_netrom_reset_circuit); + nr_disconnect(sk, ECONNRESET); + break; + default: break; } @@ -254,6 +264,11 @@ static int nr_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype } break; + case NR_RESET: + if (sysctl_netrom_reset_circuit); + nr_disconnect(sk, ECONNRESET); + break; + default: break; } diff --git a/net/netrom/nr_subr.c b/net/netrom/nr_subr.c index 587bed2674bf..bcb9946b4f56 100644 --- a/net/netrom/nr_subr.c +++ b/net/netrom/nr_subr.c @@ -210,10 +210,9 @@ void nr_write_internal(struct sock *sk, int frametype) } /* - * This routine is called when a Connect Acknowledge with the Choke Flag - * set is needed to refuse a connection. + * This routine is called to send an error reply. */ -void nr_transmit_refusal(struct sk_buff *skb, int mine) +void __nr_transmit_reply(struct sk_buff *skb, int mine, unsigned char cmdflags) { struct sk_buff *skbn; unsigned char *dptr; @@ -254,7 +253,7 @@ void nr_transmit_refusal(struct sk_buff *skb, int mine) *dptr++ = 0; } - *dptr++ = NR_CONNACK | NR_CHOKE_FLAG; + *dptr++ = cmdflags; *dptr++ = 0; if (!nr_route_frame(skbn, NULL)) diff --git a/net/netrom/sysctl_net_netrom.c b/net/netrom/sysctl_net_netrom.c index c9ed50382ea7..6bb8dda849dc 100644 --- a/net/netrom/sysctl_net_netrom.c +++ b/net/netrom/sysctl_net_netrom.c @@ -30,6 +30,7 @@ static int min_idle[] = {0 * HZ}; static int max_idle[] = {65535 * HZ}; static int min_route[] = {0}, max_route[] = {1}; static int min_fails[] = {1}, max_fails[] = {10}; +static int min_reset[] = {0}, max_reset[] = {1}; static struct ctl_table_header *nr_table_header; @@ -155,6 +156,17 @@ static ctl_table nr_table[] = { .extra1 = &min_fails, .extra2 = &max_fails }, + { + .ctl_name = NET_NETROM_RESET, + .procname = "reset", + .data = &sysctl_netrom_reset_circuit, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = &proc_dointvec_minmax, + .strategy = &sysctl_intvec, + .extra1 = &min_reset, + .extra2 = &max_reset + }, { .ctl_name = 0 } }; -- cgit