linux/net/802/garp.c
David Ward 6f66cdc3e5 net/garp: fix GID rbtree ordering
The comparison operators were backwards in both garp_attr_lookup and
garp_attr_create, so the entire GID rbtree was in reverse order.
(There was no practical side effect to this though, except that PDUs
were sent with attributes listed in reverse order, which is still
valid by the protocol. This change is only for clarity.)

Signed-off-by: David Ward <david.ward@ll.mit.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-04-13 13:10:33 -04:00

635 lines
18 KiB
C

/*
* IEEE 802.1D Generic Attribute Registration Protocol (GARP)
*
* Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
*
* 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/kernel.h>
#include <linux/timer.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/rtnetlink.h>
#include <linux/llc.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <net/llc.h>
#include <net/llc_pdu.h>
#include <net/garp.h>
#include <asm/unaligned.h>
static unsigned int garp_join_time __read_mostly = 200;
module_param(garp_join_time, uint, 0644);
MODULE_PARM_DESC(garp_join_time, "Join time in ms (default 200ms)");
MODULE_LICENSE("GPL");
static const struct garp_state_trans {
u8 state;
u8 action;
} garp_applicant_state_table[GARP_APPLICANT_MAX + 1][GARP_EVENT_MAX + 1] = {
[GARP_APPLICANT_VA] = {
[GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_AA,
.action = GARP_ACTION_S_JOIN_IN },
[GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_AA },
[GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VA },
[GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_VA },
[GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_VA },
[GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VP },
[GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_INVALID },
[GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_LA },
},
[GARP_APPLICANT_AA] = {
[GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_QA,
.action = GARP_ACTION_S_JOIN_IN },
[GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_QA },
[GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VA },
[GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_VA },
[GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_VA },
[GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VP },
[GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_INVALID },
[GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_LA },
},
[GARP_APPLICANT_QA] = {
[GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_INVALID },
[GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_QA },
[GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VA },
[GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_VA },
[GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_VP },
[GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VP },
[GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_INVALID },
[GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_LA },
},
[GARP_APPLICANT_LA] = {
[GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_VO,
.action = GARP_ACTION_S_LEAVE_EMPTY },
[GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_LA },
[GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VO },
[GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_LA },
[GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_LA },
[GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VO },
[GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_VA },
[GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_INVALID },
},
[GARP_APPLICANT_VP] = {
[GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_AA,
.action = GARP_ACTION_S_JOIN_IN },
[GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_AP },
[GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VP },
[GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_VP },
[GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_VP },
[GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VP },
[GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_INVALID },
[GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_VO },
},
[GARP_APPLICANT_AP] = {
[GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_QA,
.action = GARP_ACTION_S_JOIN_IN },
[GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_QP },
[GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VP },
[GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_VP },
[GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_VP },
[GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VP },
[GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_INVALID },
[GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_AO },
},
[GARP_APPLICANT_QP] = {
[GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_INVALID },
[GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_QP },
[GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VP },
[GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_VP },
[GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_VP },
[GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VP },
[GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_INVALID },
[GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_QO },
},
[GARP_APPLICANT_VO] = {
[GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_INVALID },
[GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_AO },
[GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VO },
[GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_VO },
[GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_VO },
[GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VO },
[GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_VP },
[GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_INVALID },
},
[GARP_APPLICANT_AO] = {
[GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_INVALID },
[GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_QO },
[GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VO },
[GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_VO },
[GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_VO },
[GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VO },
[GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_AP },
[GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_INVALID },
},
[GARP_APPLICANT_QO] = {
[GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_INVALID },
[GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_QO },
[GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VO },
[GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_VO },
[GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_VO },
[GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VO },
[GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_QP },
[GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_INVALID },
},
};
static int garp_attr_cmp(const struct garp_attr *attr,
const void *data, u8 len, u8 type)
{
if (attr->type != type)
return attr->type - type;
if (attr->dlen != len)
return attr->dlen - len;
return memcmp(attr->data, data, len);
}
static struct garp_attr *garp_attr_lookup(const struct garp_applicant *app,
const void *data, u8 len, u8 type)
{
struct rb_node *parent = app->gid.rb_node;
struct garp_attr *attr;
int d;
while (parent) {
attr = rb_entry(parent, struct garp_attr, node);
d = garp_attr_cmp(attr, data, len, type);
if (d > 0)
parent = parent->rb_left;
else if (d < 0)
parent = parent->rb_right;
else
return attr;
}
return NULL;
}
static struct garp_attr *garp_attr_create(struct garp_applicant *app,
const void *data, u8 len, u8 type)
{
struct rb_node *parent = NULL, **p = &app->gid.rb_node;
struct garp_attr *attr;
int d;
while (*p) {
parent = *p;
attr = rb_entry(parent, struct garp_attr, node);
d = garp_attr_cmp(attr, data, len, type);
if (d > 0)
p = &parent->rb_left;
else if (d < 0)
p = &parent->rb_right;
else {
/* The attribute already exists; re-use it. */
return attr;
}
}
attr = kmalloc(sizeof(*attr) + len, GFP_ATOMIC);
if (!attr)
return attr;
attr->state = GARP_APPLICANT_VO;
attr->type = type;
attr->dlen = len;
memcpy(attr->data, data, len);
rb_link_node(&attr->node, parent, p);
rb_insert_color(&attr->node, &app->gid);
return attr;
}
static void garp_attr_destroy(struct garp_applicant *app, struct garp_attr *attr)
{
rb_erase(&attr->node, &app->gid);
kfree(attr);
}
static int garp_pdu_init(struct garp_applicant *app)
{
struct sk_buff *skb;
struct garp_pdu_hdr *gp;
#define LLC_RESERVE sizeof(struct llc_pdu_un)
skb = alloc_skb(app->dev->mtu + LL_RESERVED_SPACE(app->dev),
GFP_ATOMIC);
if (!skb)
return -ENOMEM;
skb->dev = app->dev;
skb->protocol = htons(ETH_P_802_2);
skb_reserve(skb, LL_RESERVED_SPACE(app->dev) + LLC_RESERVE);
gp = (struct garp_pdu_hdr *)__skb_put(skb, sizeof(*gp));
put_unaligned(htons(GARP_PROTOCOL_ID), &gp->protocol);
app->pdu = skb;
return 0;
}
static int garp_pdu_append_end_mark(struct garp_applicant *app)
{
if (skb_tailroom(app->pdu) < sizeof(u8))
return -1;
*(u8 *)__skb_put(app->pdu, sizeof(u8)) = GARP_END_MARK;
return 0;
}
static void garp_pdu_queue(struct garp_applicant *app)
{
if (!app->pdu)
return;
garp_pdu_append_end_mark(app);
garp_pdu_append_end_mark(app);
llc_pdu_header_init(app->pdu, LLC_PDU_TYPE_U, LLC_SAP_BSPAN,
LLC_SAP_BSPAN, LLC_PDU_CMD);
llc_pdu_init_as_ui_cmd(app->pdu);
llc_mac_hdr_init(app->pdu, app->dev->dev_addr,
app->app->proto.group_address);
skb_queue_tail(&app->queue, app->pdu);
app->pdu = NULL;
}
static void garp_queue_xmit(struct garp_applicant *app)
{
struct sk_buff *skb;
while ((skb = skb_dequeue(&app->queue)))
dev_queue_xmit(skb);
}
static int garp_pdu_append_msg(struct garp_applicant *app, u8 attrtype)
{
struct garp_msg_hdr *gm;
if (skb_tailroom(app->pdu) < sizeof(*gm))
return -1;
gm = (struct garp_msg_hdr *)__skb_put(app->pdu, sizeof(*gm));
gm->attrtype = attrtype;
garp_cb(app->pdu)->cur_type = attrtype;
return 0;
}
static int garp_pdu_append_attr(struct garp_applicant *app,
const struct garp_attr *attr,
enum garp_attr_event event)
{
struct garp_attr_hdr *ga;
unsigned int len;
int err;
again:
if (!app->pdu) {
err = garp_pdu_init(app);
if (err < 0)
return err;
}
if (garp_cb(app->pdu)->cur_type != attr->type) {
if (garp_cb(app->pdu)->cur_type &&
garp_pdu_append_end_mark(app) < 0)
goto queue;
if (garp_pdu_append_msg(app, attr->type) < 0)
goto queue;
}
len = sizeof(*ga) + attr->dlen;
if (skb_tailroom(app->pdu) < len)
goto queue;
ga = (struct garp_attr_hdr *)__skb_put(app->pdu, len);
ga->len = len;
ga->event = event;
memcpy(ga->data, attr->data, attr->dlen);
return 0;
queue:
garp_pdu_queue(app);
goto again;
}
static void garp_attr_event(struct garp_applicant *app,
struct garp_attr *attr, enum garp_event event)
{
enum garp_applicant_state state;
state = garp_applicant_state_table[attr->state][event].state;
if (state == GARP_APPLICANT_INVALID)
return;
switch (garp_applicant_state_table[attr->state][event].action) {
case GARP_ACTION_NONE:
break;
case GARP_ACTION_S_JOIN_IN:
/* When appending the attribute fails, don't update state in
* order to retry on next TRANSMIT_PDU event. */
if (garp_pdu_append_attr(app, attr, GARP_JOIN_IN) < 0)
return;
break;
case GARP_ACTION_S_LEAVE_EMPTY:
garp_pdu_append_attr(app, attr, GARP_LEAVE_EMPTY);
/* As a pure applicant, sending a leave message implies that
* the attribute was unregistered and can be destroyed. */
garp_attr_destroy(app, attr);
return;
default:
WARN_ON(1);
}
attr->state = state;
}
int garp_request_join(const struct net_device *dev,
const struct garp_application *appl,
const void *data, u8 len, u8 type)
{
struct garp_port *port = rtnl_dereference(dev->garp_port);
struct garp_applicant *app = rtnl_dereference(port->applicants[appl->type]);
struct garp_attr *attr;
spin_lock_bh(&app->lock);
attr = garp_attr_create(app, data, len, type);
if (!attr) {
spin_unlock_bh(&app->lock);
return -ENOMEM;
}
garp_attr_event(app, attr, GARP_EVENT_REQ_JOIN);
spin_unlock_bh(&app->lock);
return 0;
}
EXPORT_SYMBOL_GPL(garp_request_join);
void garp_request_leave(const struct net_device *dev,
const struct garp_application *appl,
const void *data, u8 len, u8 type)
{
struct garp_port *port = rtnl_dereference(dev->garp_port);
struct garp_applicant *app = rtnl_dereference(port->applicants[appl->type]);
struct garp_attr *attr;
spin_lock_bh(&app->lock);
attr = garp_attr_lookup(app, data, len, type);
if (!attr) {
spin_unlock_bh(&app->lock);
return;
}
garp_attr_event(app, attr, GARP_EVENT_REQ_LEAVE);
spin_unlock_bh(&app->lock);
}
EXPORT_SYMBOL_GPL(garp_request_leave);
static void garp_gid_event(struct garp_applicant *app, enum garp_event event)
{
struct rb_node *node, *next;
struct garp_attr *attr;
for (node = rb_first(&app->gid);
next = node ? rb_next(node) : NULL, node != NULL;
node = next) {
attr = rb_entry(node, struct garp_attr, node);
garp_attr_event(app, attr, event);
}
}
static void garp_join_timer_arm(struct garp_applicant *app)
{
unsigned long delay;
delay = (u64)msecs_to_jiffies(garp_join_time) * net_random() >> 32;
mod_timer(&app->join_timer, jiffies + delay);
}
static void garp_join_timer(unsigned long data)
{
struct garp_applicant *app = (struct garp_applicant *)data;
spin_lock(&app->lock);
garp_gid_event(app, GARP_EVENT_TRANSMIT_PDU);
garp_pdu_queue(app);
spin_unlock(&app->lock);
garp_queue_xmit(app);
garp_join_timer_arm(app);
}
static int garp_pdu_parse_end_mark(struct sk_buff *skb)
{
if (!pskb_may_pull(skb, sizeof(u8)))
return -1;
if (*skb->data == GARP_END_MARK) {
skb_pull(skb, sizeof(u8));
return -1;
}
return 0;
}
static int garp_pdu_parse_attr(struct garp_applicant *app, struct sk_buff *skb,
u8 attrtype)
{
const struct garp_attr_hdr *ga;
struct garp_attr *attr;
enum garp_event event;
unsigned int dlen;
if (!pskb_may_pull(skb, sizeof(*ga)))
return -1;
ga = (struct garp_attr_hdr *)skb->data;
if (ga->len < sizeof(*ga))
return -1;
if (!pskb_may_pull(skb, ga->len))
return -1;
skb_pull(skb, ga->len);
dlen = sizeof(*ga) - ga->len;
if (attrtype > app->app->maxattr)
return 0;
switch (ga->event) {
case GARP_LEAVE_ALL:
if (dlen != 0)
return -1;
garp_gid_event(app, GARP_EVENT_R_LEAVE_EMPTY);
return 0;
case GARP_JOIN_EMPTY:
event = GARP_EVENT_R_JOIN_EMPTY;
break;
case GARP_JOIN_IN:
event = GARP_EVENT_R_JOIN_IN;
break;
case GARP_LEAVE_EMPTY:
event = GARP_EVENT_R_LEAVE_EMPTY;
break;
case GARP_EMPTY:
event = GARP_EVENT_R_EMPTY;
break;
default:
return 0;
}
if (dlen == 0)
return -1;
attr = garp_attr_lookup(app, ga->data, dlen, attrtype);
if (attr == NULL)
return 0;
garp_attr_event(app, attr, event);
return 0;
}
static int garp_pdu_parse_msg(struct garp_applicant *app, struct sk_buff *skb)
{
const struct garp_msg_hdr *gm;
if (!pskb_may_pull(skb, sizeof(*gm)))
return -1;
gm = (struct garp_msg_hdr *)skb->data;
if (gm->attrtype == 0)
return -1;
skb_pull(skb, sizeof(*gm));
while (skb->len > 0) {
if (garp_pdu_parse_attr(app, skb, gm->attrtype) < 0)
return -1;
if (garp_pdu_parse_end_mark(skb) < 0)
break;
}
return 0;
}
static void garp_pdu_rcv(const struct stp_proto *proto, struct sk_buff *skb,
struct net_device *dev)
{
struct garp_application *appl = proto->data;
struct garp_port *port;
struct garp_applicant *app;
const struct garp_pdu_hdr *gp;
port = rcu_dereference(dev->garp_port);
if (!port)
goto err;
app = rcu_dereference(port->applicants[appl->type]);
if (!app)
goto err;
if (!pskb_may_pull(skb, sizeof(*gp)))
goto err;
gp = (struct garp_pdu_hdr *)skb->data;
if (get_unaligned(&gp->protocol) != htons(GARP_PROTOCOL_ID))
goto err;
skb_pull(skb, sizeof(*gp));
spin_lock(&app->lock);
while (skb->len > 0) {
if (garp_pdu_parse_msg(app, skb) < 0)
break;
if (garp_pdu_parse_end_mark(skb) < 0)
break;
}
spin_unlock(&app->lock);
err:
kfree_skb(skb);
}
static int garp_init_port(struct net_device *dev)
{
struct garp_port *port;
port = kzalloc(sizeof(*port), GFP_KERNEL);
if (!port)
return -ENOMEM;
rcu_assign_pointer(dev->garp_port, port);
return 0;
}
static void garp_release_port(struct net_device *dev)
{
struct garp_port *port = rtnl_dereference(dev->garp_port);
unsigned int i;
for (i = 0; i <= GARP_APPLICATION_MAX; i++) {
if (rtnl_dereference(port->applicants[i]))
return;
}
RCU_INIT_POINTER(dev->garp_port, NULL);
kfree_rcu(port, rcu);
}
int garp_init_applicant(struct net_device *dev, struct garp_application *appl)
{
struct garp_applicant *app;
int err;
ASSERT_RTNL();
if (!rtnl_dereference(dev->garp_port)) {
err = garp_init_port(dev);
if (err < 0)
goto err1;
}
err = -ENOMEM;
app = kzalloc(sizeof(*app), GFP_KERNEL);
if (!app)
goto err2;
err = dev_mc_add(dev, appl->proto.group_address);
if (err < 0)
goto err3;
app->dev = dev;
app->app = appl;
app->gid = RB_ROOT;
spin_lock_init(&app->lock);
skb_queue_head_init(&app->queue);
rcu_assign_pointer(dev->garp_port->applicants[appl->type], app);
setup_timer(&app->join_timer, garp_join_timer, (unsigned long)app);
garp_join_timer_arm(app);
return 0;
err3:
kfree(app);
err2:
garp_release_port(dev);
err1:
return err;
}
EXPORT_SYMBOL_GPL(garp_init_applicant);
void garp_uninit_applicant(struct net_device *dev, struct garp_application *appl)
{
struct garp_port *port = rtnl_dereference(dev->garp_port);
struct garp_applicant *app = rtnl_dereference(port->applicants[appl->type]);
ASSERT_RTNL();
RCU_INIT_POINTER(port->applicants[appl->type], NULL);
/* Delete timer and generate a final TRANSMIT_PDU event to flush out
* all pending messages before the applicant is gone. */
del_timer_sync(&app->join_timer);
garp_gid_event(app, GARP_EVENT_TRANSMIT_PDU);
garp_pdu_queue(app);
garp_queue_xmit(app);
dev_mc_del(dev, appl->proto.group_address);
kfree_rcu(app, rcu);
garp_release_port(dev);
}
EXPORT_SYMBOL_GPL(garp_uninit_applicant);
int garp_register_application(struct garp_application *appl)
{
appl->proto.rcv = garp_pdu_rcv;
appl->proto.data = appl;
return stp_proto_register(&appl->proto);
}
EXPORT_SYMBOL_GPL(garp_register_application);
void garp_unregister_application(struct garp_application *appl)
{
stp_proto_unregister(&appl->proto);
}
EXPORT_SYMBOL_GPL(garp_unregister_application);