linux/net/llc/llc_conn.c

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/*
* 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 cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 08:04:11 +00:00
#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 void llc_conn_send_pdus(struct sock *sk);
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;
}
void 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);
llc_conn_send_pdus(sk);
}
/**
* 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);
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);
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
*
* Sends queued pdus to MAC layer for transmission.
*/
static void llc_conn_send_pdus(struct sock *sk)
{
struct sk_buff *skb;
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;
skb = skb2;
}
dev_queue_xmit(skb);
}
}
/**
* 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_DESTROY_BY_RCU */
if (unlikely(!atomic_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_DESTROY_BY_RCU */
if (unlikely(!atomic_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);
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);
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->sk = sk;
}
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)
{
struct sock *sk = sk_alloc(net, family, priority, prot);
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;
}
/**
* 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_conn_ac_stop_all_timers(sk, NULL);
#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 (atomic_read(&sk->sk_refcnt) != 1) {
printk(KERN_DEBUG "Destruction of LLC sock %p delayed in %s, cnt=%d\n",
sk, __func__, atomic_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;
}