File-copy from v4.4.100
This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Please refer to that tree for all history prior to this point.
Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/net/llc/llc_sap.c b/net/llc/llc_sap.c
new file mode 100644
index 0000000..5404d0d
--- /dev/null
+++ b/net/llc/llc_sap.c
@@ -0,0 +1,442 @@
+/*
+ * 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.
+ */
+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->sk, 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 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_DESTROY_BY_RCU */
+ if (unlikely(!atomic_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, count = 256 / sizeof(struct sock *);
+ struct sock *sk, *stack[count];
+ 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 < count)
+ 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);
+ }
+}