diff options
Diffstat (limited to 'net/llc/llc_sap.c')
| -rw-r--r-- | net/llc/llc_sap.c | 436 |
1 files changed, 436 insertions, 0 deletions
diff --git a/net/llc/llc_sap.c b/net/llc/llc_sap.c new file mode 100644 index 000000000..be419062e --- /dev/null +++ b/net/llc/llc_sap.c @@ -0,0 +1,436 @@ +/* + * 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 <net/tcp_states.h> +#include <linux/llc.h> +#include <linux/slab.h> + +static int llc_mac_header_len(unsigned short devtype) +{ + switch (devtype) { + case ARPHRD_ETHER: + case ARPHRD_LOOPBACK: + return sizeof(struct ethhdr); + } + return 0; +} + +/** + * llc_alloc_frame - allocates sk_buff for frame + * @dev: network device this skb will be sent over + * @type: pdu type to allocate + * @data_size: data size to allocate + * + * 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(struct sock *sk, struct net_device *dev, + u8 type, u32 data_size) +{ + int hlen = type == LLC_PDU_TYPE_U ? 3 : 4; + struct sk_buff *skb; + + hlen += llc_mac_header_len(dev->type); + skb = alloc_skb(hlen + data_size, GFP_ATOMIC); + + if (skb) { + skb_reset_mac_header(skb); + skb_reserve(skb, hlen); + skb_reset_network_header(skb); + skb_reset_transport_header(skb); + skb->protocol = htons(ETH_P_802_2); + skb->dev = dev; + if (sk != NULL) + skb_set_owner_w(skb, sk); + } + return skb; +} + +void llc_save_primitive(struct sock *sk, struct sk_buff *skb, u8 prim) +{ + struct sockaddr_llc *addr; + + /* save primitive for use by the user. */ + addr = llc_ui_skb_cb(skb); + + memset(addr, 0, sizeof(*addr)); + addr->sllc_family = 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; + const 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. + * + * This function always consumes a reference to the skb. + */ +static void llc_sap_state_process(struct llc_sap *sap, struct sk_buff *skb) +{ + struct llc_sap_state_ev *ev = llc_sap_ev(skb); + + ev->ind_cfm_flag = 0; + llc_sap_next_state(sap, skb); + + if (ev->ind_cfm_flag == LLC_IND && skb->sk->sk_state != TCP_LISTEN) { + llc_save_primitive(skb->sk, skb, ev->prim); + + /* queue skb to the user. */ + if (sock_queue_rcv_skb(skb->sk, skb) == 0) + return; + } + 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 sock *sk) +{ + struct llc_sap_state_ev *ev = llc_sap_ev(skb); + + ev->type = LLC_SAP_EV_TYPE_PDU; + ev->reason = 0; + skb_orphan(skb); + sock_hold(sk); + skb->sk = sk; + skb->destructor = sock_efree; + llc_sap_state_process(sap, skb); +} + +static inline bool llc_dgram_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_DGRAM && + llc->laddr.lsap == laddr->lsap && + ether_addr_equal(llc->laddr.mac, laddr->mac); +} + +/** + * 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, + const 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_bh(); +again: + sk_nulls_for_each_rcu(rc, node, laddr_hb) { + if (llc_dgram_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_dgram_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_bh(); + return rc; +} + +static inline bool llc_mcast_match(const struct llc_sap *sap, + const struct llc_addr *laddr, + const struct sk_buff *skb, + const struct sock *sk) +{ + struct llc_sock *llc = llc_sk(sk); + + return sk->sk_type == SOCK_DGRAM && + llc->laddr.lsap == laddr->lsap && + llc->dev == skb->dev; +} + +static void llc_do_mcast(struct llc_sap *sap, struct sk_buff *skb, + struct sock **stack, int count) +{ + struct sk_buff *skb1; + int i; + + for (i = 0; i < count; i++) { + skb1 = skb_clone(skb, GFP_ATOMIC); + if (!skb1) { + sock_put(stack[i]); + continue; + } + + llc_sap_rcv(sap, skb1, stack[i]); + sock_put(stack[i]); + } +} + +/** + * llc_sap_mcast - Deliver multicast PDU's to all matching datagram sockets. + * @sap: SAP + * @laddr: address of local LLC (MAC + SAP) + * + * Search socket list of the SAP and finds connections with same sap. + * Deliver clone to each. + */ +static void llc_sap_mcast(struct llc_sap *sap, + const struct llc_addr *laddr, + struct sk_buff *skb) +{ + int i = 0; + struct sock *sk; + struct sock *stack[256 / sizeof(struct sock *)]; + struct llc_sock *llc; + struct hlist_head *dev_hb = llc_sk_dev_hash(sap, skb->dev->ifindex); + + spin_lock_bh(&sap->sk_lock); + hlist_for_each_entry(llc, dev_hb, dev_hash_node) { + + sk = &llc->sk; + + if (!llc_mcast_match(sap, laddr, skb, sk)) + continue; + + sock_hold(sk); + if (i < ARRAY_SIZE(stack)) + stack[i++] = sk; + else { + llc_do_mcast(sap, skb, stack, i); + i = 0; + } + } + spin_unlock_bh(&sap->sk_lock); + + llc_do_mcast(sap, skb, stack, i); +} + + +void llc_sap_handler(struct llc_sap *sap, struct sk_buff *skb) +{ + struct llc_addr laddr; + + llc_pdu_decode_da(skb, laddr.mac); + llc_pdu_decode_dsap(skb, &laddr.lsap); + + if (is_multicast_ether_addr(laddr.mac)) { + llc_sap_mcast(sap, &laddr, skb); + kfree_skb(skb); + } else { + struct sock *sk = llc_lookup_dgram(sap, &laddr); + if (sk) { + llc_sap_rcv(sap, skb, sk); + sock_put(sk); + } else + kfree_skb(skb); + } +} |