diff options
Diffstat (limited to 'net/llc/llc_conn.c')
| -rw-r--r-- | net/llc/llc_conn.c | 1018 |
1 files changed, 1018 insertions, 0 deletions
diff --git a/net/llc/llc_conn.c b/net/llc/llc_conn.c new file mode 100644 index 000000000..1144cda2a --- /dev/null +++ b/net/llc/llc_conn.c @@ -0,0 +1,1018 @@ +/* + * 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 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. + * + * This function always consumes a reference to the skb. + */ +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); + + 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_skb_put; + } + + switch (ev->ind_prim) { + case LLC_DATA_PRIM: + skb_get(skb); + 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_get(skb); + 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); + } + } + 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__); + break; + default: + if (ev->ind_prim) + printk(KERN_INFO "%s: received unknown %d prim!\n", + __func__, ev->ind_prim); + /* 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); + /* No confirmation */ + break; + } +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_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, READ_ONCE(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; + + timer_setup(&llc->ack_timer.timer, llc_conn_ack_tmr_cb, 0); + llc->ack_timer.expire = sysctl_llc2_ack_timeout; + + timer_setup(&llc->pf_cycle_timer.timer, llc_conn_pf_cycle_tmr_cb, 0); + llc->pf_cycle_timer.expire = sysctl_llc2_p_timeout; + + timer_setup(&llc->rej_sent_timer.timer, llc_conn_rej_tmr_cb, 0); + llc->rej_sent_timer.expire = sysctl_llc2_rej_timeout; + + timer_setup(&llc->busy_state_timer.timer, llc_conn_busy_tmr_cb, 0); + 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 + * @net: network namespace + * @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; +} |