diff options
Diffstat (limited to 'net/llc/llc_sap.c')
| -rw-r--r-- | net/llc/llc_sap.c | 316 |
1 files changed, 316 insertions, 0 deletions
diff --git a/net/llc/llc_sap.c b/net/llc/llc_sap.c new file mode 100644 index 000000000000..965c94eb4bbc --- /dev/null +++ b/net/llc/llc_sap.c @@ -0,0 +1,316 @@ +/* + * llc_sap.c - driver routines for SAP 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 <net/llc.h> +#include <net/llc_if.h> +#include <net/llc_conn.h> +#include <net/llc_pdu.h> +#include <net/llc_sap.h> +#include <net/llc_s_ac.h> +#include <net/llc_s_ev.h> +#include <net/llc_s_st.h> +#include <net/sock.h> +#include <linux/tcp.h> +#include <linux/llc.h> + +/** + * llc_alloc_frame - allocates sk_buff for frame + * + * Allocates an sk_buff for frame and initializes sk_buff fields. + * Returns allocated skb or %NULL when out of memory. + */ +struct sk_buff *llc_alloc_frame(void) +{ + struct sk_buff *skb = alloc_skb(128, GFP_ATOMIC); + + if (skb) { + skb_reserve(skb, 50); + skb->nh.raw = skb->h.raw = skb->data; + skb->protocol = htons(ETH_P_802_2); + skb->dev = dev_base->next; + skb->mac.raw = skb->head; + } + return skb; +} + +void llc_save_primitive(struct sk_buff* skb, u8 prim) +{ + struct sockaddr_llc *addr = llc_ui_skb_cb(skb); + + /* save primitive for use by the user. */ + addr->sllc_family = skb->sk->sk_family; + addr->sllc_arphrd = skb->dev->type; + addr->sllc_test = prim == LLC_TEST_PRIM; + addr->sllc_xid = prim == LLC_XID_PRIM; + addr->sllc_ua = prim == LLC_DATAUNIT_PRIM; + llc_pdu_decode_sa(skb, addr->sllc_mac); + llc_pdu_decode_ssap(skb, &addr->sllc_sap); +} + +/** + * llc_sap_rtn_pdu - Informs upper layer on rx of an UI, XID or TEST pdu. + * @sap: pointer to SAP + * @skb: received pdu + */ +void llc_sap_rtn_pdu(struct llc_sap *sap, struct sk_buff *skb) +{ + struct llc_sap_state_ev *ev = llc_sap_ev(skb); + struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb); + + switch (LLC_U_PDU_RSP(pdu)) { + case LLC_1_PDU_CMD_TEST: + ev->prim = LLC_TEST_PRIM; break; + case LLC_1_PDU_CMD_XID: + ev->prim = LLC_XID_PRIM; break; + case LLC_1_PDU_CMD_UI: + ev->prim = LLC_DATAUNIT_PRIM; break; + } + ev->ind_cfm_flag = LLC_IND; +} + +/** + * llc_find_sap_trans - finds transition for event + * @sap: pointer to SAP + * @skb: happened event + * + * This function finds transition that matches with happened event. + * Returns the pointer to found transition on success or %NULL for + * failure. + */ +static struct llc_sap_state_trans *llc_find_sap_trans(struct llc_sap *sap, + struct sk_buff* skb) +{ + int i = 0; + struct llc_sap_state_trans *rc = NULL; + struct llc_sap_state_trans **next_trans; + struct llc_sap_state *curr_state = &llc_sap_state_table[sap->state - 1]; + /* + * Search thru events for this state until list exhausted or until + * its obvious the event is not valid for the current state + */ + for (next_trans = curr_state->transitions; next_trans[i]->ev; i++) + if (!next_trans[i]->ev(sap, skb)) { + rc = next_trans[i]; /* got event match; return it */ + break; + } + return rc; +} + +/** + * llc_exec_sap_trans_actions - execute actions related to event + * @sap: pointer to SAP + * @trans: pointer to transition that it's actions must be performed + * @skb: happened event. + * + * This function executes actions that is related to happened event. + * Returns 0 for success and 1 for failure of at least one action. + */ +static int llc_exec_sap_trans_actions(struct llc_sap *sap, + struct llc_sap_state_trans *trans, + struct sk_buff *skb) +{ + int rc = 0; + llc_sap_action_t *next_action = trans->ev_actions; + + for (; next_action && *next_action; next_action++) + if ((*next_action)(sap, skb)) + rc = 1; + return rc; +} + +/** + * llc_sap_next_state - finds transition, execs actions & change SAP state + * @sap: pointer to SAP + * @skb: happened event + * + * This function finds transition that matches with happened event, then + * executes related actions and finally changes state of SAP. It returns + * 0 on success and 1 for failure. + */ +static int llc_sap_next_state(struct llc_sap *sap, struct sk_buff *skb) +{ + int rc = 1; + struct llc_sap_state_trans *trans; + + if (sap->state > LLC_NR_SAP_STATES) + goto out; + trans = llc_find_sap_trans(sap, skb); + if (!trans) + goto out; + /* + * Got the state to which we next transition; perform the actions + * associated with this transition before actually transitioning to the + * next state + */ + rc = llc_exec_sap_trans_actions(sap, trans, skb); + if (rc) + goto out; + /* + * Transition SAP to next state if all actions execute successfully + */ + sap->state = trans->next_state; +out: + return rc; +} + +/** + * llc_sap_state_process - sends event to SAP state machine + * @sap: sap to use + * @skb: pointer to occurred event + * + * After executing actions of the event, upper layer will be indicated + * if needed(on receiving an UI frame). sk can be null for the + * datalink_proto case. + */ +static void llc_sap_state_process(struct llc_sap *sap, struct sk_buff *skb) +{ + struct llc_sap_state_ev *ev = llc_sap_ev(skb); + + /* + * We have to hold the skb, because llc_sap_next_state + * will kfree it in the sending path and we need to + * look at the skb->cb, where we encode llc_sap_state_ev. + */ + skb_get(skb); + ev->ind_cfm_flag = 0; + llc_sap_next_state(sap, skb); + if (ev->ind_cfm_flag == LLC_IND) { + if (skb->sk->sk_state == TCP_LISTEN) + kfree_skb(skb); + else { + llc_save_primitive(skb, ev->prim); + + /* queue skb to the user. */ + if (sock_queue_rcv_skb(skb->sk, skb)) + kfree_skb(skb); + } + } + kfree_skb(skb); +} + +/** + * llc_build_and_send_test_pkt - TEST interface for upper layers. + * @sap: sap to use + * @skb: packet to send + * @dmac: destination mac address + * @dsap: destination sap + * + * This function is called when upper layer wants to send a TEST pdu. + * Returns 0 for success, 1 otherwise. + */ +void llc_build_and_send_test_pkt(struct llc_sap *sap, + struct sk_buff *skb, u8 *dmac, u8 dsap) +{ + struct llc_sap_state_ev *ev = llc_sap_ev(skb); + + ev->saddr.lsap = sap->laddr.lsap; + ev->daddr.lsap = dsap; + memcpy(ev->saddr.mac, skb->dev->dev_addr, IFHWADDRLEN); + memcpy(ev->daddr.mac, dmac, IFHWADDRLEN); + + ev->type = LLC_SAP_EV_TYPE_PRIM; + ev->prim = LLC_TEST_PRIM; + ev->prim_type = LLC_PRIM_TYPE_REQ; + llc_sap_state_process(sap, skb); +} + +/** + * llc_build_and_send_xid_pkt - XID interface for upper layers + * @sap: sap to use + * @skb: packet to send + * @dmac: destination mac address + * @dsap: destination sap + * + * This function is called when upper layer wants to send a XID pdu. + * Returns 0 for success, 1 otherwise. + */ +void llc_build_and_send_xid_pkt(struct llc_sap *sap, struct sk_buff *skb, + u8 *dmac, u8 dsap) +{ + struct llc_sap_state_ev *ev = llc_sap_ev(skb); + + ev->saddr.lsap = sap->laddr.lsap; + ev->daddr.lsap = dsap; + memcpy(ev->saddr.mac, skb->dev->dev_addr, IFHWADDRLEN); + memcpy(ev->daddr.mac, dmac, IFHWADDRLEN); + + ev->type = LLC_SAP_EV_TYPE_PRIM; + ev->prim = LLC_XID_PRIM; + ev->prim_type = LLC_PRIM_TYPE_REQ; + llc_sap_state_process(sap, skb); +} + +/** + * llc_sap_rcv - sends received pdus to the sap state machine + * @sap: current sap component structure. + * @skb: received frame. + * + * Sends received pdus to the sap state machine. + */ +static void llc_sap_rcv(struct llc_sap *sap, struct sk_buff *skb) +{ + struct llc_sap_state_ev *ev = llc_sap_ev(skb); + + ev->type = LLC_SAP_EV_TYPE_PDU; + ev->reason = 0; + llc_sap_state_process(sap, skb); +} + +/** + * llc_lookup_dgram - Finds dgram socket for the local sap/mac + * @sap: SAP + * @laddr: address of local LLC (MAC + SAP) + * + * Search socket list of the SAP and finds connection using the local + * mac, and local sap. Returns pointer for socket found, %NULL otherwise. + */ +static struct sock *llc_lookup_dgram(struct llc_sap *sap, + struct llc_addr *laddr) +{ + struct sock *rc; + struct hlist_node *node; + + read_lock_bh(&sap->sk_list.lock); + sk_for_each(rc, node, &sap->sk_list.list) { + struct llc_sock *llc = llc_sk(rc); + + if (rc->sk_type == SOCK_DGRAM && + llc->laddr.lsap == laddr->lsap && + llc_mac_match(llc->laddr.mac, laddr->mac)) { + sock_hold(rc); + goto found; + } + } + rc = NULL; +found: + read_unlock_bh(&sap->sk_list.lock); + return rc; +} + +void llc_sap_handler(struct llc_sap *sap, struct sk_buff *skb) +{ + struct llc_addr laddr; + struct sock *sk; + + llc_pdu_decode_da(skb, laddr.mac); + llc_pdu_decode_dsap(skb, &laddr.lsap); + + sk = llc_lookup_dgram(sap, &laddr); + if (sk) { + skb->sk = sk; + llc_sap_rcv(sap, skb); + sock_put(sk); + } else + kfree_skb(skb); +} |