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coral / linux-imx / 883334ceaa4f97249b8e1c0d76e4805c2c7eefa3 / . / net / llc / llc_conn.c
blob: 56c3fb5cc8058b3a01025db3fe516ce42ecd4f75 [file] [log] [blame]
/*
* llc_conn.c - Driver routines for connection component.
*
* Copyright (c) 1997 by Procom Technology, Inc.
* 2001-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
*
* This program can be redistributed or modified under the terms of the
* GNU General Public License as published by the Free Software Foundation.
* This program is distributed without any warranty or implied warranty
* of merchantability or fitness for a particular purpose.
*
* See the GNU General Public License for more details.
*/
#include <linux/init.h>
#include <linux/slab.h>
#include <net/llc_sap.h>
#include <net/llc_conn.h>
#include <net/sock.h>
#include <net/tcp_states.h>
#include <net/llc_c_ev.h>
#include <net/llc_c_ac.h>
#include <net/llc_c_st.h>
#include <net/llc_pdu.h>
#if 0
#define dprintk(args...) printk(KERN_DEBUG args)
#else
#define dprintk(args...)
#endif
static int llc_find_offset(int state, int ev_type);
static int llc_conn_send_pdus(struct sock *sk, struct sk_buff *skb);
static int llc_conn_service(struct sock *sk, struct sk_buff *skb);
static int llc_exec_conn_trans_actions(struct sock *sk,
struct llc_conn_state_trans *trans,
struct sk_buff *ev);
static struct llc_conn_state_trans *llc_qualify_conn_ev(struct sock *sk,
struct sk_buff *skb);
/* Offset table on connection states transition diagram */
static int llc_offset_table[NBR_CONN_STATES][NBR_CONN_EV];
int sysctl_llc2_ack_timeout = LLC2_ACK_TIME * HZ;
int sysctl_llc2_p_timeout = LLC2_P_TIME * HZ;
int sysctl_llc2_rej_timeout = LLC2_REJ_TIME * HZ;
int sysctl_llc2_busy_timeout = LLC2_BUSY_TIME * HZ;
/**
* llc_conn_state_process - sends event to connection state machine
* @sk: connection
* @skb: occurred event
*
* Sends an event to connection state machine. After processing event
* (executing it's actions and changing state), upper layer will be
* indicated or confirmed, if needed. Returns 0 for success, 1 for
* failure. The socket lock has to be held before calling this function.
*/
int llc_conn_state_process(struct sock *sk, struct sk_buff *skb)
{
int rc;
struct llc_sock *llc = llc_sk(skb->sk);
struct llc_conn_state_ev *ev = llc_conn_ev(skb);
/*
* We have to hold the skb, because llc_conn_service will kfree it in
* the sending path and we need to look at the skb->cb, where we encode
* llc_conn_state_ev.
*/
skb_get(skb);
ev->ind_prim = ev->cfm_prim = 0;
/*
* Send event to state machine
*/
rc = llc_conn_service(skb->sk, skb);
if (unlikely(rc != 0)) {
printk(KERN_ERR "%s: llc_conn_service failed\n", __func__);
goto out_kfree_skb;
}
if (unlikely(!ev->ind_prim && !ev->cfm_prim)) {
/* indicate or confirm not required */
if (!skb->next)
goto out_kfree_skb;
goto out_skb_put;
}
if (unlikely(ev->ind_prim && ev->cfm_prim)) /* Paranoia */
skb_get(skb);
switch (ev->ind_prim) {
case LLC_DATA_PRIM:
llc_save_primitive(sk, skb, LLC_DATA_PRIM);
if (unlikely(sock_queue_rcv_skb(sk, skb))) {
/*
* shouldn't happen
*/
printk(KERN_ERR "%s: sock_queue_rcv_skb failed!\n",
__func__);
kfree_skb(skb);
}
break;
case LLC_CONN_PRIM:
/*
* Can't be sock_queue_rcv_skb, because we have to leave the
* skb->sk pointing to the newly created struct sock in
* llc_conn_handler. -acme
*/
skb_queue_tail(&sk->sk_receive_queue, skb);
sk->sk_state_change(sk);
break;
case LLC_DISC_PRIM:
sock_hold(sk);
if (sk->sk_type == SOCK_STREAM &&
sk->sk_state == TCP_ESTABLISHED) {
sk->sk_shutdown = SHUTDOWN_MASK;
sk->sk_socket->state = SS_UNCONNECTED;
sk->sk_state = TCP_CLOSE;
if (!sock_flag(sk, SOCK_DEAD)) {
sock_set_flag(sk, SOCK_DEAD);
sk->sk_state_change(sk);
}
}
kfree_skb(skb);
sock_put(sk);
break;
case LLC_RESET_PRIM:
/*
* FIXME:
* RESET is not being notified to upper layers for now
*/
printk(KERN_INFO "%s: received a reset ind!\n", __func__);
kfree_skb(skb);
break;
default:
if (ev->ind_prim) {
printk(KERN_INFO "%s: received unknown %d prim!\n",
__func__, ev->ind_prim);
kfree_skb(skb);
}
/* No indication */
break;
}
switch (ev->cfm_prim) {
case LLC_DATA_PRIM:
if (!llc_data_accept_state(llc->state))
sk->sk_write_space(sk);
else
rc = llc->failed_data_req = 1;
break;
case LLC_CONN_PRIM:
if (sk->sk_type == SOCK_STREAM &&
sk->sk_state == TCP_SYN_SENT) {
if (ev->status) {
sk->sk_socket->state = SS_UNCONNECTED;
sk->sk_state = TCP_CLOSE;
} else {
sk->sk_socket->state = SS_CONNECTED;
sk->sk_state = TCP_ESTABLISHED;
}
sk->sk_state_change(sk);
}
break;
case LLC_DISC_PRIM:
sock_hold(sk);
if (sk->sk_type == SOCK_STREAM && sk->sk_state == TCP_CLOSING) {
sk->sk_socket->state = SS_UNCONNECTED;
sk->sk_state = TCP_CLOSE;
sk->sk_state_change(sk);
}
sock_put(sk);
break;
case LLC_RESET_PRIM:
/*
* FIXME:
* RESET is not being notified to upper layers for now
*/
printk(KERN_INFO "%s: received a reset conf!\n", __func__);
break;
default:
if (ev->cfm_prim) {
printk(KERN_INFO "%s: received unknown %d prim!\n",
__func__, ev->cfm_prim);
break;
}
goto out_skb_put; /* No confirmation */
}
out_kfree_skb:
kfree_skb(skb);
out_skb_put:
kfree_skb(skb);
return rc;
}
int llc_conn_send_pdu(struct sock *sk, struct sk_buff *skb)
{
/* queue PDU to send to MAC layer */
skb_queue_tail(&sk->sk_write_queue, skb);
return llc_conn_send_pdus(sk, skb);
}
/**
* llc_conn_rtn_pdu - sends received data pdu to upper layer
* @sk: Active connection
* @skb: Received data frame
*
* Sends received data pdu to upper layer (by using indicate function).
* Prepares service parameters (prim and prim_data). calling indication
* function will be done in llc_conn_state_process.
*/
void llc_conn_rtn_pdu(struct sock *sk, struct sk_buff *skb)
{
struct llc_conn_state_ev *ev = llc_conn_ev(skb);
ev->ind_prim = LLC_DATA_PRIM;
}
/**
* llc_conn_resend_i_pdu_as_cmd - resend all all unacknowledged I PDUs
* @sk: active connection
* @nr: NR
* @first_p_bit: p_bit value of first pdu
*
* Resend all unacknowledged I PDUs, starting with the NR; send first as
* command PDU with P bit equal first_p_bit; if more than one send
* subsequent as command PDUs with P bit equal zero (0).
*/
void llc_conn_resend_i_pdu_as_cmd(struct sock *sk, u8 nr, u8 first_p_bit)
{
struct sk_buff *skb;
struct llc_pdu_sn *pdu;
u16 nbr_unack_pdus;
struct llc_sock *llc;
u8 howmany_resend = 0;
llc_conn_remove_acked_pdus(sk, nr, &nbr_unack_pdus);
if (!nbr_unack_pdus)
goto out;
/*
* Process unack PDUs only if unack queue is not empty; remove
* appropriate PDUs, fix them up, and put them on mac_pdu_q.
*/
llc = llc_sk(sk);
while ((skb = skb_dequeue(&llc->pdu_unack_q)) != NULL) {
pdu = llc_pdu_sn_hdr(skb);
llc_pdu_set_cmd_rsp(skb, LLC_PDU_CMD);
llc_pdu_set_pf_bit(skb, first_p_bit);
skb_queue_tail(&sk->sk_write_queue, skb);
first_p_bit = 0;
llc->vS = LLC_I_GET_NS(pdu);
howmany_resend++;
}
if (howmany_resend > 0)
llc->vS = (llc->vS + 1) % LLC_2_SEQ_NBR_MODULO;
/* any PDUs to re-send are queued up; start sending to MAC */
llc_conn_send_pdus(sk, NULL);
out:;
}
/**
* llc_conn_resend_i_pdu_as_rsp - Resend all unacknowledged I PDUs
* @sk: active connection.
* @nr: NR
* @first_f_bit: f_bit value of first pdu.
*
* Resend all unacknowledged I PDUs, starting with the NR; send first as
* response PDU with F bit equal first_f_bit; if more than one send
* subsequent as response PDUs with F bit equal zero (0).
*/
void llc_conn_resend_i_pdu_as_rsp(struct sock *sk, u8 nr, u8 first_f_bit)
{
struct sk_buff *skb;
u16 nbr_unack_pdus;
struct llc_sock *llc = llc_sk(sk);
u8 howmany_resend = 0;
llc_conn_remove_acked_pdus(sk, nr, &nbr_unack_pdus);
if (!nbr_unack_pdus)
goto out;
/*
* Process unack PDUs only if unack queue is not empty; remove
* appropriate PDUs, fix them up, and put them on mac_pdu_q
*/
while ((skb = skb_dequeue(&llc->pdu_unack_q)) != NULL) {
struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
llc_pdu_set_cmd_rsp(skb, LLC_PDU_RSP);
llc_pdu_set_pf_bit(skb, first_f_bit);
skb_queue_tail(&sk->sk_write_queue, skb);
first_f_bit = 0;
llc->vS = LLC_I_GET_NS(pdu);
howmany_resend++;
}
if (howmany_resend > 0)
llc->vS = (llc->vS + 1) % LLC_2_SEQ_NBR_MODULO;
/* any PDUs to re-send are queued up; start sending to MAC */
llc_conn_send_pdus(sk, NULL);
out:;
}
/**
* llc_conn_remove_acked_pdus - Removes acknowledged pdus from tx queue
* @sk: active connection
* nr: NR
* how_many_unacked: size of pdu_unack_q after removing acked pdus
*
* Removes acknowledged pdus from transmit queue (pdu_unack_q). Returns
* the number of pdus that removed from queue.
*/
int llc_conn_remove_acked_pdus(struct sock *sk, u8 nr, u16 *how_many_unacked)
{
int pdu_pos, i;
struct sk_buff *skb;
struct llc_pdu_sn *pdu;
int nbr_acked = 0;
struct llc_sock *llc = llc_sk(sk);
int q_len = skb_queue_len(&llc->pdu_unack_q);
if (!q_len)
goto out;
skb = skb_peek(&llc->pdu_unack_q);
pdu = llc_pdu_sn_hdr(skb);
/* finding position of last acked pdu in queue */
pdu_pos = ((int)LLC_2_SEQ_NBR_MODULO + (int)nr -
(int)LLC_I_GET_NS(pdu)) % LLC_2_SEQ_NBR_MODULO;
for (i = 0; i < pdu_pos && i < q_len; i++) {
skb = skb_dequeue(&llc->pdu_unack_q);
kfree_skb(skb);
nbr_acked++;
}
out:
*how_many_unacked = skb_queue_len(&llc->pdu_unack_q);
return nbr_acked;
}
/**
* llc_conn_send_pdus - Sends queued PDUs
* @sk: active connection
* @hold_skb: the skb held by caller, or NULL if does not care
*
* Sends queued pdus to MAC layer for transmission. When @hold_skb is
* NULL, always return 0. Otherwise, return 0 if @hold_skb is sent
* successfully, or 1 for failure.
*/
static int llc_conn_send_pdus(struct sock *sk, struct sk_buff *hold_skb)
{
struct sk_buff *skb;
int ret = 0;
while ((skb = skb_dequeue(&sk->sk_write_queue)) != NULL) {
struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
if (LLC_PDU_TYPE_IS_I(pdu) &&
!(skb->dev->flags & IFF_LOOPBACK)) {
struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
skb_queue_tail(&llc_sk(sk)->pdu_unack_q, skb);
if (!skb2)
break;
dev_queue_xmit(skb2);
} else {
bool is_target = skb == hold_skb;
int rc;
if (is_target)
skb_get(skb);
rc = dev_queue_xmit(skb);
if (is_target)
ret = rc;
}
}
return ret;
}
/**
* llc_conn_service - finds transition and changes state of connection
* @sk: connection
* @skb: happened event
*
* This function finds transition that matches with happened event, then
* executes related actions and finally changes state of connection.
* Returns 0 for success, 1 for failure.
*/
static int llc_conn_service(struct sock *sk, struct sk_buff *skb)
{
int rc = 1;
struct llc_sock *llc = llc_sk(sk);
struct llc_conn_state_trans *trans;
if (llc->state > NBR_CONN_STATES)
goto out;
rc = 0;
trans = llc_qualify_conn_ev(sk, skb);
if (trans) {
rc = llc_exec_conn_trans_actions(sk, trans, skb);
if (!rc && trans->next_state != NO_STATE_CHANGE) {
llc->state = trans->next_state;
if (!llc_data_accept_state(llc->state))
sk->sk_state_change(sk);
}
}
out:
return rc;
}
/**
* llc_qualify_conn_ev - finds transition for event
* @sk: connection
* @skb: happened event
*
* This function finds transition that matches with happened event.
* Returns pointer to found transition on success, %NULL otherwise.
*/
static struct llc_conn_state_trans *llc_qualify_conn_ev(struct sock *sk,
struct sk_buff *skb)
{
struct llc_conn_state_trans **next_trans;
const llc_conn_ev_qfyr_t *next_qualifier;
struct llc_conn_state_ev *ev = llc_conn_ev(skb);
struct llc_sock *llc = llc_sk(sk);
struct llc_conn_state *curr_state =
&llc_conn_state_table[llc->state - 1];
/* search thru events for this state until
* list exhausted or until no more
*/
for (next_trans = curr_state->transitions +
llc_find_offset(llc->state - 1, ev->type);
(*next_trans)->ev; next_trans++) {
if (!((*next_trans)->ev)(sk, skb)) {
/* got POSSIBLE event match; the event may require
* qualification based on the values of a number of
* state flags; if all qualifications are met (i.e.,
* if all qualifying functions return success, or 0,
* then this is THE event we're looking for
*/
for (next_qualifier = (*next_trans)->ev_qualifiers;
next_qualifier && *next_qualifier &&
!(*next_qualifier)(sk, skb); next_qualifier++)
/* nothing */;
if (!next_qualifier || !*next_qualifier)
/* all qualifiers executed successfully; this is
* our transition; return it so we can perform
* the associated actions & change the state
*/
return *next_trans;
}
}
return NULL;
}
/**
* llc_exec_conn_trans_actions - executes related actions
* @sk: connection
* @trans: transition that it's actions must be performed
* @skb: event
*
* Executes actions that is related to happened event. Returns 0 for
* success, 1 to indicate failure of at least one action.
*/
static int llc_exec_conn_trans_actions(struct sock *sk,
struct llc_conn_state_trans *trans,
struct sk_buff *skb)
{
int rc = 0;
const llc_conn_action_t *next_action;
for (next_action = trans->ev_actions;
next_action && *next_action; next_action++) {
int rc2 = (*next_action)(sk, skb);
if (rc2 == 2) {
rc = rc2;
break;
} else if (rc2)
rc = 1;
}
return rc;
}
static inline bool llc_estab_match(const struct llc_sap *sap,
const struct llc_addr *daddr,
const struct llc_addr *laddr,
const struct sock *sk)
{
struct llc_sock *llc = llc_sk(sk);
return llc->laddr.lsap == laddr->lsap &&
llc->daddr.lsap == daddr->lsap &&
ether_addr_equal(llc->laddr.mac, laddr->mac) &&
ether_addr_equal(llc->daddr.mac, daddr->mac);
}
/**
* __llc_lookup_established - Finds connection for the remote/local sap/mac
* @sap: SAP
* @daddr: address of remote LLC (MAC + SAP)
* @laddr: address of local LLC (MAC + SAP)
*
* Search connection list of the SAP and finds connection using the remote
* mac, remote sap, local mac, and local sap. Returns pointer for
* connection found, %NULL otherwise.
* Caller has to make sure local_bh is disabled.
*/
static struct sock *__llc_lookup_established(struct llc_sap *sap,
struct llc_addr *daddr,
struct llc_addr *laddr)
{
struct sock *rc;
struct hlist_nulls_node *node;
int slot = llc_sk_laddr_hashfn(sap, laddr);
struct hlist_nulls_head *laddr_hb = &sap->sk_laddr_hash[slot];
rcu_read_lock();
again:
sk_nulls_for_each_rcu(rc, node, laddr_hb) {
if (llc_estab_match(sap, daddr, laddr, rc)) {
/* Extra checks required by SLAB_TYPESAFE_BY_RCU */
if (unlikely(!refcount_inc_not_zero(&rc->sk_refcnt)))
goto again;
if (unlikely(llc_sk(rc)->sap != sap ||
!llc_estab_match(sap, daddr, laddr, rc))) {
sock_put(rc);
continue;
}
goto found;
}
}
rc = NULL;
/*
* if the nulls value we got at the end of this lookup is
* not the expected one, we must restart lookup.
* We probably met an item that was moved to another chain.
*/
if (unlikely(get_nulls_value(node) != slot))
goto again;
found:
rcu_read_unlock();
return rc;
}
struct sock *llc_lookup_established(struct llc_sap *sap,
struct llc_addr *daddr,
struct llc_addr *laddr)
{
struct sock *sk;
local_bh_disable();
sk = __llc_lookup_established(sap, daddr, laddr);
local_bh_enable();
return sk;
}
static inline bool llc_listener_match(const struct llc_sap *sap,
const struct llc_addr *laddr,
const struct sock *sk)
{
struct llc_sock *llc = llc_sk(sk);
return sk->sk_type == SOCK_STREAM && sk->sk_state == TCP_LISTEN &&
llc->laddr.lsap == laddr->lsap &&
ether_addr_equal(llc->laddr.mac, laddr->mac);
}
static struct sock *__llc_lookup_listener(struct llc_sap *sap,
struct llc_addr *laddr)
{
struct sock *rc;
struct hlist_nulls_node *node;
int slot = llc_sk_laddr_hashfn(sap, laddr);
struct hlist_nulls_head *laddr_hb = &sap->sk_laddr_hash[slot];
rcu_read_lock();
again:
sk_nulls_for_each_rcu(rc, node, laddr_hb) {
if (llc_listener_match(sap, laddr, rc)) {
/* Extra checks required by SLAB_TYPESAFE_BY_RCU */
if (unlikely(!refcount_inc_not_zero(&rc->sk_refcnt)))
goto again;
if (unlikely(llc_sk(rc)->sap != sap ||
!llc_listener_match(sap, laddr, rc))) {
sock_put(rc);
continue;
}
goto found;
}
}
rc = NULL;
/*
* if the nulls value we got at the end of this lookup is
* not the expected one, we must restart lookup.
* We probably met an item that was moved to another chain.
*/
if (unlikely(get_nulls_value(node) != slot))
goto again;
found:
rcu_read_unlock();
return rc;
}
/**
* llc_lookup_listener - Finds listener for local MAC + SAP
* @sap: SAP
* @laddr: address of local LLC (MAC + SAP)
*
* Search connection list of the SAP and finds connection listening on
* local mac, and local sap. Returns pointer for parent socket found,
* %NULL otherwise.
* Caller has to make sure local_bh is disabled.
*/
static struct sock *llc_lookup_listener(struct llc_sap *sap,
struct llc_addr *laddr)
{
static struct llc_addr null_addr;
struct sock *rc = __llc_lookup_listener(sap, laddr);
if (!rc)
rc = __llc_lookup_listener(sap, &null_addr);
return rc;
}
static struct sock *__llc_lookup(struct llc_sap *sap,
struct llc_addr *daddr,
struct llc_addr *laddr)
{
struct sock *sk = __llc_lookup_established(sap, daddr, laddr);
return sk ? : llc_lookup_listener(sap, laddr);
}
/**
* llc_data_accept_state - designates if in this state data can be sent.
* @state: state of connection.
*
* Returns 0 if data can be sent, 1 otherwise.
*/
u8 llc_data_accept_state(u8 state)
{
return state != LLC_CONN_STATE_NORMAL && state != LLC_CONN_STATE_BUSY &&
state != LLC_CONN_STATE_REJ;
}
/**
* llc_find_next_offset - finds offset for next category of transitions
* @state: state table.
* @offset: start offset.
*
* Finds offset of next category of transitions in transition table.
* Returns the start index of next category.
*/
static u16 __init llc_find_next_offset(struct llc_conn_state *state, u16 offset)
{
u16 cnt = 0;
struct llc_conn_state_trans **next_trans;
for (next_trans = state->transitions + offset;
(*next_trans)->ev; next_trans++)
++cnt;
return cnt;
}
/**
* llc_build_offset_table - builds offset table of connection
*
* Fills offset table of connection state transition table
* (llc_offset_table).
*/
void __init llc_build_offset_table(void)
{
struct llc_conn_state *curr_state;
int state, ev_type, next_offset;
for (state = 0; state < NBR_CONN_STATES; state++) {
curr_state = &llc_conn_state_table[state];
next_offset = 0;
for (ev_type = 0; ev_type < NBR_CONN_EV; ev_type++) {
llc_offset_table[state][ev_type] = next_offset;
next_offset += llc_find_next_offset(curr_state,
next_offset) + 1;
}
}
}
/**
* llc_find_offset - finds start offset of category of transitions
* @state: state of connection
* @ev_type: type of happened event
*
* Finds start offset of desired category of transitions. Returns the
* desired start offset.
*/
static int llc_find_offset(int state, int ev_type)
{
int rc = 0;
/* at this stage, llc_offset_table[..][2] is not important. it is for
* init_pf_cycle and I don't know what is it.
*/
switch (ev_type) {
case LLC_CONN_EV_TYPE_PRIM:
rc = llc_offset_table[state][0]; break;
case LLC_CONN_EV_TYPE_PDU:
rc = llc_offset_table[state][4]; break;
case LLC_CONN_EV_TYPE_SIMPLE:
rc = llc_offset_table[state][1]; break;
case LLC_CONN_EV_TYPE_P_TMR:
case LLC_CONN_EV_TYPE_ACK_TMR:
case LLC_CONN_EV_TYPE_REJ_TMR:
case LLC_CONN_EV_TYPE_BUSY_TMR:
rc = llc_offset_table[state][3]; break;
}
return rc;
}
/**
* llc_sap_add_socket - adds a socket to a SAP
* @sap: SAP
* @sk: socket
*
* This function adds a socket to the hash tables of a SAP.
*/
void llc_sap_add_socket(struct llc_sap *sap, struct sock *sk)
{
struct llc_sock *llc = llc_sk(sk);
struct hlist_head *dev_hb = llc_sk_dev_hash(sap, llc->dev->ifindex);
struct hlist_nulls_head *laddr_hb = llc_sk_laddr_hash(sap, &llc->laddr);
llc_sap_hold(sap);
llc_sk(sk)->sap = sap;
spin_lock_bh(&sap->sk_lock);
sock_set_flag(sk, SOCK_RCU_FREE);
sap->sk_count++;
sk_nulls_add_node_rcu(sk, laddr_hb);
hlist_add_head(&llc->dev_hash_node, dev_hb);
spin_unlock_bh(&sap->sk_lock);
}
/**
* llc_sap_remove_socket - removes a socket from SAP
* @sap: SAP
* @sk: socket
*
* This function removes a connection from the hash tables of a SAP if
* the connection was in this list.
*/
void llc_sap_remove_socket(struct llc_sap *sap, struct sock *sk)
{
struct llc_sock *llc = llc_sk(sk);
spin_lock_bh(&sap->sk_lock);
sk_nulls_del_node_init_rcu(sk);
hlist_del(&llc->dev_hash_node);
sap->sk_count--;
spin_unlock_bh(&sap->sk_lock);
llc_sap_put(sap);
}
/**
* llc_conn_rcv - sends received pdus to the connection state machine
* @sk: current connection structure.
* @skb: received frame.
*
* Sends received pdus to the connection state machine.
*/
static int llc_conn_rcv(struct sock *sk, struct sk_buff *skb)
{
struct llc_conn_state_ev *ev = llc_conn_ev(skb);
ev->type = LLC_CONN_EV_TYPE_PDU;
ev->reason = 0;
return llc_conn_state_process(sk, skb);
}
static struct sock *llc_create_incoming_sock(struct sock *sk,
struct net_device *dev,
struct llc_addr *saddr,
struct llc_addr *daddr)
{
struct sock *newsk = llc_sk_alloc(sock_net(sk), sk->sk_family, GFP_ATOMIC,
sk->sk_prot, 0);
struct llc_sock *newllc, *llc = llc_sk(sk);
if (!newsk)
goto out;
newllc = llc_sk(newsk);
memcpy(&newllc->laddr, daddr, sizeof(newllc->laddr));
memcpy(&newllc->daddr, saddr, sizeof(newllc->daddr));
newllc->dev = dev;
dev_hold(dev);
llc_sap_add_socket(llc->sap, newsk);
llc_sap_hold(llc->sap);
out:
return newsk;
}
void llc_conn_handler(struct llc_sap *sap, struct sk_buff *skb)
{
struct llc_addr saddr, daddr;
struct sock *sk;
llc_pdu_decode_sa(skb, saddr.mac);
llc_pdu_decode_ssap(skb, &saddr.lsap);
llc_pdu_decode_da(skb, daddr.mac);
llc_pdu_decode_dsap(skb, &daddr.lsap);
sk = __llc_lookup(sap, &saddr, &daddr);
if (!sk)
goto drop;
bh_lock_sock(sk);
/*
* This has to be done here and not at the upper layer ->accept
* method because of the way the PROCOM state machine works:
* it needs to set several state variables (see, for instance,
* llc_adm_actions_2 in net/llc/llc_c_st.c) and send a packet to
* the originator of the new connection, and this state has to be
* in the newly created struct sock private area. -acme
*/
if (unlikely(sk->sk_state == TCP_LISTEN)) {
struct sock *newsk = llc_create_incoming_sock(sk, skb->dev,
&saddr, &daddr);
if (!newsk)
goto drop_unlock;
skb_set_owner_r(skb, newsk);
} else {
/*
* Can't be skb_set_owner_r, this will be done at the
* llc_conn_state_process function, later on, when we will use
* skb_queue_rcv_skb to send it to upper layers, this is
* another trick required to cope with how the PROCOM state
* machine works. -acme
*/
skb_orphan(skb);
sock_hold(sk);
skb->sk = sk;
skb->destructor = sock_efree;
}
if (!sock_owned_by_user(sk))
llc_conn_rcv(sk, skb);
else {
dprintk("%s: adding to backlog...\n", __func__);
llc_set_backlog_type(skb, LLC_PACKET);
if (sk_add_backlog(sk, skb, sk->sk_rcvbuf))
goto drop_unlock;
}
out:
bh_unlock_sock(sk);
sock_put(sk);
return;
drop:
kfree_skb(skb);
return;
drop_unlock:
kfree_skb(skb);
goto out;
}
#undef LLC_REFCNT_DEBUG
#ifdef LLC_REFCNT_DEBUG
static atomic_t llc_sock_nr;
#endif
/**
* llc_backlog_rcv - Processes rx frames and expired timers.
* @sk: LLC sock (p8022 connection)
* @skb: queued rx frame or event
*
* This function processes frames that has received and timers that has
* expired during sending an I pdu (refer to data_req_handler). frames
* queue by llc_rcv function (llc_mac.c) and timers queue by timer
* callback functions(llc_c_ac.c).
*/
static int llc_backlog_rcv(struct sock *sk, struct sk_buff *skb)
{
int rc = 0;
struct llc_sock *llc = llc_sk(sk);
if (likely(llc_backlog_type(skb) == LLC_PACKET)) {
if (likely(llc->state > 1)) /* not closed */
rc = llc_conn_rcv(sk, skb);
else
goto out_kfree_skb;
} else if (llc_backlog_type(skb) == LLC_EVENT) {
/* timer expiration event */
if (likely(llc->state > 1)) /* not closed */
rc = llc_conn_state_process(sk, skb);
else
goto out_kfree_skb;
} else {
printk(KERN_ERR "%s: invalid skb in backlog\n", __func__);
goto out_kfree_skb;
}
out:
return rc;
out_kfree_skb:
kfree_skb(skb);
goto out;
}
/**
* llc_sk_init - Initializes a socket with default llc values.
* @sk: socket to initialize.
*
* Initializes a socket with default llc values.
*/
static void llc_sk_init(struct sock *sk)
{
struct llc_sock *llc = llc_sk(sk);
llc->state = LLC_CONN_STATE_ADM;
llc->inc_cntr = llc->dec_cntr = 2;
llc->dec_step = llc->connect_step = 1;
setup_timer(&llc->ack_timer.timer, llc_conn_ack_tmr_cb,
(unsigned long)sk);
llc->ack_timer.expire = sysctl_llc2_ack_timeout;
setup_timer(&llc->pf_cycle_timer.timer, llc_conn_pf_cycle_tmr_cb,
(unsigned long)sk);
llc->pf_cycle_timer.expire = sysctl_llc2_p_timeout;
setup_timer(&llc->rej_sent_timer.timer, llc_conn_rej_tmr_cb,
(unsigned long)sk);
llc->rej_sent_timer.expire = sysctl_llc2_rej_timeout;
setup_timer(&llc->busy_state_timer.timer, llc_conn_busy_tmr_cb,
(unsigned long)sk);
llc->busy_state_timer.expire = sysctl_llc2_busy_timeout;
llc->n2 = 2; /* max retransmit */
llc->k = 2; /* tx win size, will adjust dynam */
llc->rw = 128; /* rx win size (opt and equal to
* tx_win of remote LLC) */
skb_queue_head_init(&llc->pdu_unack_q);
sk->sk_backlog_rcv = llc_backlog_rcv;
}
/**
* llc_sk_alloc - Allocates LLC sock
* @family: upper layer protocol family
* @priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc)
*
* Allocates a LLC sock and initializes it. Returns the new LLC sock
* or %NULL if there's no memory available for one
*/
struct sock *llc_sk_alloc(struct net *net, int family, gfp_t priority, struct proto *prot, int kern)
{
struct sock *sk = sk_alloc(net, family, priority, prot, kern);
if (!sk)
goto out;
llc_sk_init(sk);
sock_init_data(NULL, sk);
#ifdef LLC_REFCNT_DEBUG
atomic_inc(&llc_sock_nr);
printk(KERN_DEBUG "LLC socket %p created in %s, now we have %d alive\n", sk,
__func__, atomic_read(&llc_sock_nr));
#endif
out:
return sk;
}
void llc_sk_stop_all_timers(struct sock *sk, bool sync)
{
struct llc_sock *llc = llc_sk(sk);
if (sync) {
del_timer_sync(&llc->pf_cycle_timer.timer);
del_timer_sync(&llc->ack_timer.timer);
del_timer_sync(&llc->rej_sent_timer.timer);
del_timer_sync(&llc->busy_state_timer.timer);
} else {
del_timer(&llc->pf_cycle_timer.timer);
del_timer(&llc->ack_timer.timer);
del_timer(&llc->rej_sent_timer.timer);
del_timer(&llc->busy_state_timer.timer);
}
llc->ack_must_be_send = 0;
llc->ack_pf = 0;
}
/**
* llc_sk_free - Frees a LLC socket
* @sk - socket to free
*
* Frees a LLC socket
*/
void llc_sk_free(struct sock *sk)
{
struct llc_sock *llc = llc_sk(sk);
llc->state = LLC_CONN_OUT_OF_SVC;
/* Stop all (possibly) running timers */
llc_sk_stop_all_timers(sk, true);
#ifdef DEBUG_LLC_CONN_ALLOC
printk(KERN_INFO "%s: unackq=%d, txq=%d\n", __func__,
skb_queue_len(&llc->pdu_unack_q),
skb_queue_len(&sk->sk_write_queue));
#endif
skb_queue_purge(&sk->sk_receive_queue);
skb_queue_purge(&sk->sk_write_queue);
skb_queue_purge(&llc->pdu_unack_q);
#ifdef LLC_REFCNT_DEBUG
if (refcount_read(&sk->sk_refcnt) != 1) {
printk(KERN_DEBUG "Destruction of LLC sock %p delayed in %s, cnt=%d\n",
sk, __func__, refcount_read(&sk->sk_refcnt));
printk(KERN_DEBUG "%d LLC sockets are still alive\n",
atomic_read(&llc_sock_nr));
} else {
atomic_dec(&llc_sock_nr);
printk(KERN_DEBUG "LLC socket %p released in %s, %d are still alive\n", sk,
__func__, atomic_read(&llc_sock_nr));
}
#endif
sock_put(sk);
}
/**
* llc_sk_reset - resets a connection
* @sk: LLC socket to reset
*
* Resets a connection to the out of service state. Stops its timers
* and frees any frames in the queues of the connection.
*/
void llc_sk_reset(struct sock *sk)
{
struct llc_sock *llc = llc_sk(sk);
llc_conn_ac_stop_all_timers(sk, NULL);
skb_queue_purge(&sk->sk_write_queue);
skb_queue_purge(&llc->pdu_unack_q);
llc->remote_busy_flag = 0;
llc->cause_flag = 0;
llc->retry_count = 0;
llc_conn_set_p_flag(sk, 0);
llc->f_flag = 0;
llc->s_flag = 0;
llc->ack_pf = 0;
llc->first_pdu_Ns = 0;
llc->ack_must_be_send = 0;
llc->dec_step = 1;
llc->inc_cntr = 2;
llc->dec_cntr = 2;
llc->X = 0;
llc->failed_data_req = 0 ;
llc->last_nr = 0;
}