/* * 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); } }