*******************************************************************************
**
** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
-** Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
+** Copyright (C) 2004-2021 Red Hat, Inc. All rights reserved.
**
**
*******************************************************************************
/*
* midcomms.c
*
- * This is the appallingly named "mid-level" comms layer.
+ * This is the appallingly named "mid-level" comms layer. It takes care about
+ * deliver an on application layer "reliable" communication above the used
+ * lowcomms transport layer.
*
- * Its purpose is to take packets from the "real" comms layer,
- * split them up into packets and pass them to the interested
- * part of the locking mechanism.
+ * How it works:
*
- * It also takes messages from the locking layer, formats them
- * into packets and sends them to the comms layer.
+ * Each nodes keeps track of all send DLM messages in send_queue with a sequence
+ * number. The receive will send an DLM_ACK message back for every DLM message
+ * received at the other side. If a reconnect happens in lowcomms we will send
+ * all unacknowledged dlm messages again. The receiving side might drop any already
+ * received message by comparing sequence numbers.
+ *
+ * How version detection works:
+ *
+ * Due the fact that dlm has pre-configured node addresses on every side
+ * it is in it's nature that every side connects at starts to transmit
+ * dlm messages which ends in a race. However DLM_RCOM_NAMES, DLM_RCOM_STATUS
+ * and their replies are the first messages which are exchanges. Due backwards
+ * compatibility these messages are not covered by the midcomms re-transmission
+ * layer. These messages have their own re-transmission handling in the dlm
+ * application layer. The version field of every node will be set on these RCOM
+ * messages as soon as they arrived and the node isn't yet part of the nodes
+ * hash. There exists also logic to detect version mismatched if something weird
+ * going on or the first messages isn't an expected one.
+ *
+ * Termination:
+ *
+ * The midcomms layer does a 4 way handshake for termination on DLM protocol
+ * like TCP supports it with half-closed socket support. SCTP doesn't support
+ * half-closed socket, so we do it on DLM layer. Also socket shutdown() can be
+ * interrupted by .e.g. tcp reset itself. Additional there exists the othercon
+ * paradigm in lowcomms which cannot be easily without breaking backwards
+ * compatibility. A node cannot send anything to another node when a DLM_FIN
+ * message was send. There exists additional logic to print a warning if
+ * DLM wants to do it. There exists a state handling like RFC 793 but reduced
+ * to termination only. The event "member removal event" describes the cluster
+ * manager removed the node from internal lists, at this point DLM does not
+ * send any message to the other node. There exists two cases:
+ *
+ * 1. The cluster member was removed and we received a FIN
+ * OR
+ * 2. We received a FIN but the member was not removed yet
+ *
+ * One of these cases will do the CLOSE_WAIT to LAST_ACK change.
+ *
+ *
+ * +---------+
+ * | CLOSED |
+ * +---------+
+ * | add member/receive RCOM version
+ * | detection msg
+ * V
+ * +---------+
+ * | ESTAB |
+ * +---------+
+ * CLOSE | | rcv FIN
+ * ------- | | -------
+ * +---------+ snd FIN / \ snd ACK +---------+
+ * | FIN |<----------------- ------------------>| CLOSE |
+ * | WAIT-1 |------------------ | WAIT |
+ * +---------+ rcv FIN \ +---------+
+ * | rcv ACK of FIN ------- | CLOSE | member
+ * | -------------- snd ACK | ------- | removal
+ * V x V snd FIN V event
+ * +---------+ +---------+ +---------+
+ * |FINWAIT-2| | CLOSING | | LAST-ACK|
+ * +---------+ +---------+ +---------+
+ * | rcv ACK of FIN | rcv ACK of FIN |
+ * | rcv FIN -------------- | -------------- |
+ * | ------- x V x V
+ * \ snd ACK +---------+ +---------+
+ * ------------------------>| CLOSED | | CLOSED |
+ * +---------+ +---------+
+ *
+ * NOTE: any state can interrupted by midcomms_close() and state will be
+ * switched to CLOSED in case of fencing. There exists also some timeout
+ * handling when we receive the version detection RCOM messages which is
+ * made by observation.
+ *
+ * Future improvements:
+ *
+ * There exists some known issues/improvements of the dlm handling. Some
+ * of them should be done in a next major dlm version bump which makes
+ * it incompatible with previous versions.
+ *
+ * Unaligned memory access:
+ *
+ * There exists cases when the dlm message buffer length is not aligned
+ * to 8 byte. However seems nobody detected any problem with it. This
+ * can be fixed in the next major version bump of dlm.
+ *
+ * Version detection:
+ *
+ * The version detection and how it's done is related to backwards
+ * compatibility. There exists better ways to make a better handling.
+ * However this should be changed in the next major version bump of dlm.
+ *
+ * Ack handling:
+ *
+ * Currently we send an ack message for every dlm message. However we
+ * can ack multiple dlm messages with one ack by just delaying the ack
+ * message. Will reduce some traffic but makes the drop detection slower.
+ *
+ * Tail Size checking:
+ *
+ * There exists a message tail payload in e.g. DLM_MSG however we don't
+ * check it against the message length yet regarding to the receive buffer
+ * length. That need to be validated.
+ *
+ * Fencing bad nodes:
+ *
+ * At timeout places or weird sequence number behaviours we should send
+ * a fencing request to the cluster manager.
*/
+/* Debug switch to enable a 5 seconds sleep waiting of a termination.
+ * This can be useful to test fencing while termination is running.
+ * This requires a setup with only gfs2 as dlm user, so that the
+ * last umount will terminate the connection.
+ *
+ * However it became useful to test, while the 5 seconds block in umount
+ * just press the reset button. In a lot of dropping the termination
+ * process can could take several seconds.
+ */
+#define DLM_DEBUG_FENCE_TERMINATION 0
+
+#include <net/tcp.h>
+
#include "dlm_internal.h"
#include "lowcomms.h"
#include "config.h"
#include "lock.h"
+#include "util.h"
#include "midcomms.h"
-struct dlm_mhandle *dlm_midcomms_get_mhandle(int nodeid, int len,
- gfp_t allocation, char **ppc)
+/* init value for sequence numbers for testing purpose only e.g. overflows */
+#define DLM_SEQ_INIT 0
+/* 3 minutes wait to sync ending of dlm */
+#define DLM_SHUTDOWN_TIMEOUT msecs_to_jiffies(3 * 60 * 1000)
+#define DLM_VERSION_NOT_SET 0
+
+struct midcomms_node {
+ int nodeid;
+ uint32_t version;
+ uint32_t seq_send;
+ uint32_t seq_next;
+ /* These queues are unbound because we cannot drop any message in dlm.
+ * We could send a fence signal for a specific node to the cluster
+ * manager if queues hits some maximum value, however this handling
+ * not supported yet.
+ */
+ struct list_head send_queue;
+ spinlock_t send_queue_lock;
+ atomic_t send_queue_cnt;
+#define DLM_NODE_FLAG_CLOSE 1
+#define DLM_NODE_FLAG_STOP_TX 2
+#define DLM_NODE_FLAG_STOP_RX 3
+ unsigned long flags;
+ wait_queue_head_t shutdown_wait;
+
+ /* dlm tcp termination state */
+#define DLM_CLOSED 1
+#define DLM_ESTABLISHED 2
+#define DLM_FIN_WAIT1 3
+#define DLM_FIN_WAIT2 4
+#define DLM_CLOSE_WAIT 5
+#define DLM_LAST_ACK 6
+#define DLM_CLOSING 7
+ int state;
+ spinlock_t state_lock;
+
+ /* counts how many lockspaces are using this node
+ * this refcount is necessary to determine if the
+ * node wants to disconnect.
+ */
+ int users;
+
+ struct hlist_node hlist;
+ struct rcu_head rcu;
+};
+
+struct dlm_mhandle {
+ const struct dlm_header *inner_hd;
+ struct midcomms_node *node;
+ struct dlm_opts *opts;
+ struct dlm_msg *msg;
+ bool committed;
+ uint32_t seq;
+
+ void (*ack_rcv)(struct midcomms_node *node);
+
+ /* get_mhandle/commit srcu idx exchange */
+ int idx;
+
+ struct list_head list;
+ struct rcu_head rcu;
+};
+
+static struct hlist_head node_hash[CONN_HASH_SIZE];
+static DEFINE_SPINLOCK(nodes_lock);
+DEFINE_STATIC_SRCU(nodes_srcu);
+
+/* This mutex prevents that midcomms_close() is running while
+ * stop() or remove(). As I experienced invalid memory access
+ * behaviours when DLM_DEBUG_FENCE_TERMINATION is enabled and
+ * resetting machines. I will end in some double deletion in nodes
+ * datastructure.
+ */
+static DEFINE_MUTEX(close_lock);
+
+static inline const char *dlm_state_str(int state)
{
- return (struct dlm_mhandle *)dlm_lowcomms_new_msg(nodeid, len,
- allocation, ppc,
- NULL, NULL);
+ switch (state) {
+ case DLM_CLOSED:
+ return "CLOSED";
+ case DLM_ESTABLISHED:
+ return "ESTABLISHED";
+ case DLM_FIN_WAIT1:
+ return "FIN_WAIT1";
+ case DLM_FIN_WAIT2:
+ return "FIN_WAIT2";
+ case DLM_CLOSE_WAIT:
+ return "CLOSE_WAIT";
+ case DLM_LAST_ACK:
+ return "LAST_ACK";
+ case DLM_CLOSING:
+ return "CLOSING";
+ default:
+ return "UNKNOWN";
+ }
}
-void dlm_midcomms_commit_mhandle(struct dlm_mhandle *mh)
+static struct midcomms_node *__find_node(int nodeid, int r)
{
- dlm_lowcomms_commit_msg((struct dlm_msg *)mh);
- dlm_lowcomms_put_msg((struct dlm_msg *)mh);
+ struct midcomms_node *node;
+
+ hlist_for_each_entry_rcu(node, &node_hash[r], hlist) {
+ if (node->nodeid == nodeid)
+ return node;
+ }
+
+ return NULL;
}
-void dlm_midcomms_add_member(int nodeid) { }
+static void dlm_mhandle_release(struct rcu_head *rcu)
+{
+ struct dlm_mhandle *mh = container_of(rcu, struct dlm_mhandle, rcu);
-void dlm_midcomms_remove_member(int nodeid) { }
+ dlm_lowcomms_put_msg(mh->msg);
+ kfree(mh);
+}
-int dlm_midcomms_start(void)
+static void dlm_send_queue_flush(struct midcomms_node *node)
{
- return dlm_lowcomms_start();
+ struct dlm_mhandle *mh;
+
+ pr_debug("flush midcomms send queue of node %d\n", node->nodeid);
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(mh, &node->send_queue, list) {
+ spin_lock(&node->send_queue_lock);
+ list_del_rcu(&mh->list);
+ spin_unlock(&node->send_queue_lock);
+
+ atomic_dec(&node->send_queue_cnt);
+
+ call_rcu(&mh->rcu, dlm_mhandle_release);
+ }
+ rcu_read_unlock();
}
-void dlm_midcomms_shutdown(void)
+static void midcomms_node_reset(struct midcomms_node *node)
{
- dlm_lowcomms_shutdown();
+ pr_debug("reset node %d\n", node->nodeid);
+
+ node->seq_next = DLM_SEQ_INIT;
+ node->seq_send = DLM_SEQ_INIT;
+ node->version = DLM_VERSION_NOT_SET;
+ node->flags = 0;
+
+ dlm_send_queue_flush(node);
+ node->state = DLM_CLOSED;
+ wake_up(&node->shutdown_wait);
}
-int dlm_midcomms_close(int nodeid)
+static struct midcomms_node *nodeid2node(int nodeid, gfp_t alloc)
+{
+ struct midcomms_node *node, *tmp;
+ int r = nodeid_hash(nodeid);
+
+ node = __find_node(nodeid, r);
+ if (node || !alloc)
+ return node;
+
+ node = kmalloc(sizeof(*node), alloc);
+ if (!node)
+ return NULL;
+
+ node->nodeid = nodeid;
+ spin_lock_init(&node->state_lock);
+ spin_lock_init(&node->send_queue_lock);
+ atomic_set(&node->send_queue_cnt, 0);
+ INIT_LIST_HEAD(&node->send_queue);
+ init_waitqueue_head(&node->shutdown_wait);
+ node->users = 0;
+ midcomms_node_reset(node);
+
+ spin_lock(&nodes_lock);
+ /* check again if there was somebody else
+ * earlier here to add the node
+ */
+ tmp = __find_node(nodeid, r);
+ if (tmp) {
+ spin_unlock(&nodes_lock);
+ kfree(node);
+ return tmp;
+ }
+
+ hlist_add_head_rcu(&node->hlist, &node_hash[r]);
+ spin_unlock(&nodes_lock);
+ return node;
+}
+
+static int dlm_send_ack(int nodeid, uint32_t seq)
+{
+ int mb_len = sizeof(struct dlm_header);
+ struct dlm_header *m_header;
+ struct dlm_msg *msg;
+ char *ppc;
+
+ msg = dlm_lowcomms_new_msg(nodeid, mb_len, GFP_NOFS, &ppc,
+ NULL, NULL);
+ if (!msg)
+ return -ENOMEM;
+
+ m_header = (struct dlm_header *)ppc;
+
+ m_header->h_version = (DLM_HEADER_MAJOR | DLM_HEADER_MINOR);
+ m_header->h_nodeid = dlm_our_nodeid();
+ m_header->h_length = mb_len;
+ m_header->h_cmd = DLM_ACK;
+ m_header->u.h_seq = seq;
+
+ header_out(m_header);
+ dlm_lowcomms_commit_msg(msg);
+ dlm_lowcomms_put_msg(msg);
+
+ return 0;
+}
+
+static int dlm_send_fin(struct midcomms_node *node,
+ void (*ack_rcv)(struct midcomms_node *node))
+{
+ int mb_len = sizeof(struct dlm_header);
+ struct dlm_header *m_header;
+ struct dlm_mhandle *mh;
+ char *ppc;
+
+ mh = dlm_midcomms_get_mhandle(node->nodeid, mb_len, GFP_NOFS, &ppc);
+ if (!mh)
+ return -ENOMEM;
+
+ mh->ack_rcv = ack_rcv;
+
+ m_header = (struct dlm_header *)ppc;
+
+ m_header->h_version = (DLM_HEADER_MAJOR | DLM_HEADER_MINOR);
+ m_header->h_nodeid = dlm_our_nodeid();
+ m_header->h_length = mb_len;
+ m_header->h_cmd = DLM_FIN;
+
+ header_out(m_header);
+
+ pr_debug("sending fin msg to node %d\n", node->nodeid);
+ dlm_midcomms_commit_mhandle(mh);
+ set_bit(DLM_NODE_FLAG_STOP_TX, &node->flags);
+
+ return 0;
+}
+
+static void dlm_receive_ack(struct midcomms_node *node, uint32_t seq)
+{
+ struct dlm_mhandle *mh;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(mh, &node->send_queue, list) {
+ if (before(mh->seq, seq)) {
+ spin_lock(&node->send_queue_lock);
+ list_del_rcu(&mh->list);
+ spin_unlock(&node->send_queue_lock);
+
+ atomic_dec(&node->send_queue_cnt);
+
+ if (mh->ack_rcv)
+ mh->ack_rcv(node);
+
+ call_rcu(&mh->rcu, dlm_mhandle_release);
+ } else {
+ /* send queue should be ordered */
+ break;
+ }
+ }
+ rcu_read_unlock();
+}
+
+static void dlm_pas_fin_ack_rcv(struct midcomms_node *node)
+{
+ spin_lock(&node->state_lock);
+ pr_debug("receive passive fin ack from node %d with state %s\n",
+ node->nodeid, dlm_state_str(node->state));
+
+ switch (node->state) {
+ case DLM_LAST_ACK:
+ /* DLM_CLOSED */
+ midcomms_node_reset(node);
+ break;
+ case DLM_CLOSED:
+ /* not valid but somehow we got what we want */
+ wake_up(&node->shutdown_wait);
+ break;
+ default:
+ spin_unlock(&node->state_lock);
+ log_print("%s: unexpected state: %d\n",
+ __func__, node->state);
+ WARN_ON(1);
+ return;
+ }
+ spin_unlock(&node->state_lock);
+}
+
+static void dlm_midcomms_receive_buffer(union dlm_packet *p,
+ struct midcomms_node *node,
+ uint32_t seq)
+{
+ if (seq == node->seq_next) {
+ node->seq_next++;
+ /* send ack before fin */
+ dlm_send_ack(node->nodeid, node->seq_next);
+
+ switch (p->header.h_cmd) {
+ case DLM_FIN:
+ spin_lock(&node->state_lock);
+ pr_debug("receive fin msg from node %d with state %s\n",
+ node->nodeid, dlm_state_str(node->state));
+
+ switch (node->state) {
+ case DLM_ESTABLISHED:
+ node->state = DLM_CLOSE_WAIT;
+ pr_debug("switch node %d to state %s\n",
+ node->nodeid, dlm_state_str(node->state));
+ /* passive shutdown DLM_LAST_ACK case 1
+ * additional we check if the node is used by
+ * cluster manager events at all.
+ */
+ if (node->users == 0) {
+ node->state = DLM_LAST_ACK;
+ pr_debug("switch node %d to state %s case 1\n",
+ node->nodeid, dlm_state_str(node->state));
+ spin_unlock(&node->state_lock);
+ goto send_fin;
+ }
+ break;
+ case DLM_FIN_WAIT1:
+ node->state = DLM_CLOSING;
+ pr_debug("switch node %d to state %s\n",
+ node->nodeid, dlm_state_str(node->state));
+ break;
+ case DLM_FIN_WAIT2:
+ midcomms_node_reset(node);
+ pr_debug("switch node %d to state %s\n",
+ node->nodeid, dlm_state_str(node->state));
+ wake_up(&node->shutdown_wait);
+ break;
+ case DLM_LAST_ACK:
+ /* probably remove_member caught it, do nothing */
+ break;
+ default:
+ spin_unlock(&node->state_lock);
+ log_print("%s: unexpected state: %d\n",
+ __func__, node->state);
+ WARN_ON(1);
+ return;
+ }
+ spin_unlock(&node->state_lock);
+
+ set_bit(DLM_NODE_FLAG_STOP_RX, &node->flags);
+ break;
+ default:
+ WARN_ON(test_bit(DLM_NODE_FLAG_STOP_RX, &node->flags));
+ dlm_receive_buffer(p, node->nodeid);
+ break;
+ }
+ } else {
+ /* retry to ack message which we already have by sending back
+ * current node->seq_next number as ack.
+ */
+ if (seq < node->seq_next)
+ dlm_send_ack(node->nodeid, node->seq_next);
+
+ log_print_ratelimited("ignore dlm msg because seq mismatch, seq: %u, expected: %u, nodeid: %d",
+ seq, node->seq_next, node->nodeid);
+ }
+
+ return;
+
+send_fin:
+ set_bit(DLM_NODE_FLAG_STOP_RX, &node->flags);
+ dlm_send_fin(node, dlm_pas_fin_ack_rcv);
+}
+
+static struct midcomms_node *
+dlm_midcomms_recv_node_lookup(int nodeid, const union dlm_packet *p,
+ uint16_t msglen, int (*cb)(struct midcomms_node *node))
+{
+ struct midcomms_node *node = NULL;
+ gfp_t allocation = 0;
+ int ret;
+
+ switch (p->header.h_cmd) {
+ case DLM_RCOM:
+ if (msglen < sizeof(struct dlm_rcom)) {
+ log_print("rcom msg too small: %u, will skip this message from node %d",
+ msglen, nodeid);
+ return NULL;
+ }
+
+ switch (le32_to_cpu(p->rcom.rc_type)) {
+ case DLM_RCOM_NAMES:
+ fallthrough;
+ case DLM_RCOM_NAMES_REPLY:
+ fallthrough;
+ case DLM_RCOM_STATUS:
+ fallthrough;
+ case DLM_RCOM_STATUS_REPLY:
+ node = nodeid2node(nodeid, 0);
+ if (node) {
+ spin_lock(&node->state_lock);
+ if (node->state != DLM_ESTABLISHED)
+ pr_debug("receive begin RCOM msg from node %d with state %s\n",
+ node->nodeid, dlm_state_str(node->state));
+
+ switch (node->state) {
+ case DLM_CLOSED:
+ node->state = DLM_ESTABLISHED;
+ pr_debug("switch node %d to state %s\n",
+ node->nodeid, dlm_state_str(node->state));
+ break;
+ case DLM_ESTABLISHED:
+ break;
+ default:
+ /* some invalid state passive shutdown
+ * was failed, we try to reset and
+ * hope it will go on.
+ */
+ log_print("reset node %d because shutdown stucked",
+ node->nodeid);
+
+ midcomms_node_reset(node);
+ node->state = DLM_ESTABLISHED;
+ break;
+ }
+ spin_unlock(&node->state_lock);
+ }
+
+ allocation = GFP_NOFS;
+ break;
+ default:
+ break;
+ }
+
+ break;
+ default:
+ break;
+ }
+
+ node = nodeid2node(nodeid, allocation);
+ if (!node) {
+ log_print_ratelimited("received dlm message cmd %d nextcmd %d from node %d in an invalid sequence",
+ p->header.h_cmd, p->opts.o_nextcmd, nodeid);
+ return NULL;
+ }
+
+ ret = cb(node);
+ if (ret < 0)
+ return NULL;
+
+ return node;
+}
+
+static int dlm_midcomms_version_check_3_2(struct midcomms_node *node)
+{
+ switch (node->version) {
+ case DLM_VERSION_NOT_SET:
+ node->version = DLM_VERSION_3_2;
+ log_print("version 0x%08x for node %d detected", DLM_VERSION_3_2,
+ node->nodeid);
+ break;
+ case DLM_VERSION_3_2:
+ break;
+ default:
+ log_print_ratelimited("version mismatch detected, assumed 0x%08x but node %d has 0x%08x",
+ DLM_VERSION_3_2, node->nodeid, node->version);
+ return -1;
+ }
+
+ return 0;
+}
+
+static int dlm_opts_check_msglen(union dlm_packet *p, uint16_t msglen, int nodeid)
+{
+ int len = msglen;
+
+ /* we only trust outer header msglen because
+ * it's checked against receive buffer length.
+ */
+ if (len < sizeof(struct dlm_opts))
+ return -1;
+ len -= sizeof(struct dlm_opts);
+
+ if (len < le16_to_cpu(p->opts.o_optlen))
+ return -1;
+ len -= le16_to_cpu(p->opts.o_optlen);
+
+ switch (p->opts.o_nextcmd) {
+ case DLM_FIN:
+ if (len < sizeof(struct dlm_header)) {
+ log_print("fin too small: %d, will skip this message from node %d",
+ len, nodeid);
+ return -1;
+ }
+
+ break;
+ case DLM_MSG:
+ if (len < sizeof(struct dlm_message)) {
+ log_print("msg too small: %d, will skip this message from node %d",
+ msglen, nodeid);
+ return -1;
+ }
+
+ break;
+ case DLM_RCOM:
+ if (len < sizeof(struct dlm_rcom)) {
+ log_print("rcom msg too small: %d, will skip this message from node %d",
+ len, nodeid);
+ return -1;
+ }
+
+ break;
+ default:
+ log_print("unsupported o_nextcmd received: %u, will skip this message from node %d",
+ p->opts.o_nextcmd, nodeid);
+ return -1;
+ }
+
+ return 0;
+}
+
+static void dlm_midcomms_receive_buffer_3_2(union dlm_packet *p, int nodeid)
+{
+ uint16_t msglen = le16_to_cpu(p->header.h_length);
+ struct midcomms_node *node;
+ uint32_t seq;
+ int ret, idx;
+
+ idx = srcu_read_lock(&nodes_srcu);
+ node = dlm_midcomms_recv_node_lookup(nodeid, p, msglen,
+ dlm_midcomms_version_check_3_2);
+ if (!node)
+ goto out;
+
+ switch (p->header.h_cmd) {
+ case DLM_RCOM:
+ /* these rcom message we use to determine version.
+ * they have their own retransmission handling and
+ * are the first messages of dlm.
+ *
+ * length already checked.
+ */
+ switch (le32_to_cpu(p->rcom.rc_type)) {
+ case DLM_RCOM_NAMES:
+ fallthrough;
+ case DLM_RCOM_NAMES_REPLY:
+ fallthrough;
+ case DLM_RCOM_STATUS:
+ fallthrough;
+ case DLM_RCOM_STATUS_REPLY:
+ break;
+ default:
+ log_print("unsupported rcom type received: %u, will skip this message from node %d",
+ le32_to_cpu(p->rcom.rc_type), nodeid);
+ goto out;
+ }
+
+ WARN_ON(test_bit(DLM_NODE_FLAG_STOP_RX, &node->flags));
+ dlm_receive_buffer(p, nodeid);
+ break;
+ case DLM_OPTS:
+ seq = le32_to_cpu(p->header.u.h_seq);
+
+ ret = dlm_opts_check_msglen(p, msglen, nodeid);
+ if (ret < 0) {
+ log_print("opts msg too small: %u, will skip this message from node %d",
+ msglen, nodeid);
+ goto out;
+ }
+
+ p = (union dlm_packet *)((unsigned char *)p->opts.o_opts +
+ le16_to_cpu(p->opts.o_optlen));
+
+ /* recheck inner msglen just if it's not garbage */
+ msglen = le16_to_cpu(p->header.h_length);
+ switch (p->header.h_cmd) {
+ case DLM_RCOM:
+ if (msglen < sizeof(struct dlm_rcom)) {
+ log_print("inner rcom msg too small: %u, will skip this message from node %d",
+ msglen, nodeid);
+ goto out;
+ }
+
+ break;
+ case DLM_MSG:
+ if (msglen < sizeof(struct dlm_message)) {
+ log_print("inner msg too small: %u, will skip this message from node %d",
+ msglen, nodeid);
+ goto out;
+ }
+
+ break;
+ case DLM_FIN:
+ if (msglen < sizeof(struct dlm_header)) {
+ log_print("inner fin too small: %u, will skip this message from node %d",
+ msglen, nodeid);
+ goto out;
+ }
+
+ break;
+ default:
+ log_print("unsupported inner h_cmd received: %u, will skip this message from node %d",
+ msglen, nodeid);
+ goto out;
+ }
+
+ dlm_midcomms_receive_buffer(p, node, seq);
+ break;
+ case DLM_ACK:
+ seq = le32_to_cpu(p->header.u.h_seq);
+ dlm_receive_ack(node, seq);
+ break;
+ default:
+ log_print("unsupported h_cmd received: %u, will skip this message from node %d",
+ p->header.h_cmd, nodeid);
+ break;
+ }
+
+out:
+ srcu_read_unlock(&nodes_srcu, idx);
+}
+
+static int dlm_midcomms_version_check_3_1(struct midcomms_node *node)
{
- return dlm_lowcomms_close(nodeid);
+ switch (node->version) {
+ case DLM_VERSION_NOT_SET:
+ node->version = DLM_VERSION_3_1;
+ log_print("version 0x%08x for node %d detected", DLM_VERSION_3_1,
+ node->nodeid);
+ break;
+ case DLM_VERSION_3_1:
+ break;
+ default:
+ log_print_ratelimited("version mismatch detected, assumed 0x%08x but node %d has 0x%08x",
+ DLM_VERSION_3_1, node->nodeid, node->version);
+ return -1;
+ }
+
+ return 0;
+}
+
+static void dlm_midcomms_receive_buffer_3_1(union dlm_packet *p, int nodeid)
+{
+ uint16_t msglen = le16_to_cpu(p->header.h_length);
+ struct midcomms_node *node;
+ int idx;
+
+ idx = srcu_read_lock(&nodes_srcu);
+ node = dlm_midcomms_recv_node_lookup(nodeid, p, msglen,
+ dlm_midcomms_version_check_3_1);
+ if (!node) {
+ srcu_read_unlock(&nodes_srcu, idx);
+ return;
+ }
+ srcu_read_unlock(&nodes_srcu, idx);
+
+ switch (p->header.h_cmd) {
+ case DLM_RCOM:
+ /* length already checked */
+ break;
+ case DLM_MSG:
+ if (msglen < sizeof(struct dlm_message)) {
+ log_print("msg too small: %u, will skip this message from node %d",
+ msglen, nodeid);
+ return;
+ }
+
+ break;
+ default:
+ log_print("unsupported h_cmd received: %u, will skip this message from node %d",
+ p->header.h_cmd, nodeid);
+ return;
+ }
+
+ dlm_receive_buffer(p, nodeid);
}
/*
if (msglen > len)
break;
- switch (hd->h_cmd) {
- case DLM_MSG:
- if (msglen < sizeof(struct dlm_message)) {
- log_print("dlm msg too small: %u, will skip this message",
- msglen);
- goto skip;
- }
-
+ switch (le32_to_cpu(hd->h_version)) {
+ case DLM_VERSION_3_1:
+ dlm_midcomms_receive_buffer_3_1((union dlm_packet *)ptr, nodeid);
break;
- case DLM_RCOM:
- if (msglen < sizeof(struct dlm_rcom)) {
- log_print("dlm rcom msg too small: %u, will skip this message",
- msglen);
- goto skip;
- }
-
+ case DLM_VERSION_3_2:
+ dlm_midcomms_receive_buffer_3_2((union dlm_packet *)ptr, nodeid);
break;
default:
- log_print("unsupported h_cmd received: %u, will skip this message",
- hd->h_cmd);
- goto skip;
+ log_print("received invalid version header: %u from node %d, will skip this message",
+ le32_to_cpu(hd->h_version), nodeid);
+ break;
}
- dlm_receive_buffer((union dlm_packet *)ptr, nodeid);
-
-skip:
ret += msglen;
len -= msglen;
ptr += msglen;
return ret;
}
+
+void dlm_midcomms_unack_msg_resend(int nodeid)
+{
+ struct midcomms_node *node;
+ struct dlm_mhandle *mh;
+ int idx, ret;
+
+ idx = srcu_read_lock(&nodes_srcu);
+ node = nodeid2node(nodeid, 0);
+ if (!node) {
+ srcu_read_unlock(&nodes_srcu, idx);
+ return;
+ }
+
+ /* old protocol, we don't support to retransmit on failure */
+ switch (node->version) {
+ case DLM_VERSION_3_2:
+ break;
+ default:
+ srcu_read_unlock(&nodes_srcu, idx);
+ return;
+ }
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(mh, &node->send_queue, list) {
+ if (!mh->committed)
+ continue;
+
+ ret = dlm_lowcomms_resend_msg(mh->msg);
+ if (!ret)
+ log_print_ratelimited("retransmit dlm msg, seq %u, nodeid %d",
+ mh->seq, node->nodeid);
+ }
+ rcu_read_unlock();
+ srcu_read_unlock(&nodes_srcu, idx);
+}
+
+static void dlm_fill_opts_header(struct dlm_opts *opts, uint16_t inner_len,
+ uint32_t seq)
+{
+ opts->o_header.h_cmd = DLM_OPTS;
+ opts->o_header.h_version = (DLM_HEADER_MAJOR | DLM_HEADER_MINOR);
+ opts->o_header.h_nodeid = dlm_our_nodeid();
+ opts->o_header.h_length = DLM_MIDCOMMS_OPT_LEN + inner_len;
+ opts->o_header.u.h_seq = seq;
+ header_out(&opts->o_header);
+}
+
+static void midcomms_new_msg_cb(struct dlm_mhandle *mh)
+{
+ atomic_inc(&mh->node->send_queue_cnt);
+
+ spin_lock(&mh->node->send_queue_lock);
+ list_add_tail_rcu(&mh->list, &mh->node->send_queue);
+ spin_unlock(&mh->node->send_queue_lock);
+
+ mh->seq = mh->node->seq_send++;
+}
+
+static struct dlm_msg *dlm_midcomms_get_msg_3_2(struct dlm_mhandle *mh, int nodeid,
+ int len, gfp_t allocation, char **ppc)
+{
+ struct dlm_opts *opts;
+ struct dlm_msg *msg;
+
+ msg = dlm_lowcomms_new_msg(nodeid, len + DLM_MIDCOMMS_OPT_LEN,
+ allocation, ppc, midcomms_new_msg_cb, mh);
+ if (!msg)
+ return NULL;
+
+ opts = (struct dlm_opts *)*ppc;
+ mh->opts = opts;
+
+ /* add possible options here */
+ dlm_fill_opts_header(opts, len, mh->seq);
+
+ *ppc += sizeof(*opts);
+ mh->inner_hd = (const struct dlm_header *)*ppc;
+ return msg;
+}
+
+struct dlm_mhandle *dlm_midcomms_get_mhandle(int nodeid, int len,
+ gfp_t allocation, char **ppc)
+{
+ struct midcomms_node *node;
+ struct dlm_mhandle *mh;
+ struct dlm_msg *msg;
+ int idx;
+
+ idx = srcu_read_lock(&nodes_srcu);
+ node = nodeid2node(nodeid, 0);
+ if (!node) {
+ WARN_ON_ONCE(1);
+ goto err;
+ }
+
+ /* this is a bug, however we going on and hope it will be resolved */
+ WARN_ON(test_bit(DLM_NODE_FLAG_STOP_TX, &node->flags));
+
+ mh = kzalloc(sizeof(*mh), GFP_NOFS);
+ if (!mh)
+ goto err;
+
+ mh->idx = idx;
+ mh->node = node;
+
+ switch (node->version) {
+ case DLM_VERSION_3_1:
+ msg = dlm_lowcomms_new_msg(nodeid, len, allocation, ppc,
+ NULL, NULL);
+ if (!msg) {
+ kfree(mh);
+ goto err;
+ }
+
+ break;
+ case DLM_VERSION_3_2:
+ msg = dlm_midcomms_get_msg_3_2(mh, nodeid, len, allocation,
+ ppc);
+ if (!msg) {
+ kfree(mh);
+ goto err;
+ }
+
+ break;
+ default:
+ kfree(mh);
+ WARN_ON(1);
+ goto err;
+ }
+
+ mh->msg = msg;
+
+ /* keep in mind that is a must to call
+ * dlm_midcomms_commit_msg() which releases
+ * nodes_srcu using mh->idx which is assumed
+ * here that the application will call it.
+ */
+ return mh;
+
+err:
+ srcu_read_unlock(&nodes_srcu, idx);
+ return NULL;
+}
+
+static void dlm_midcomms_commit_msg_3_2(struct dlm_mhandle *mh)
+{
+ /* nexthdr chain for fast lookup */
+ mh->opts->o_nextcmd = mh->inner_hd->h_cmd;
+ mh->committed = true;
+ dlm_lowcomms_commit_msg(mh->msg);
+}
+
+void dlm_midcomms_commit_mhandle(struct dlm_mhandle *mh)
+{
+ switch (mh->node->version) {
+ case DLM_VERSION_3_1:
+ srcu_read_unlock(&nodes_srcu, mh->idx);
+
+ dlm_lowcomms_commit_msg(mh->msg);
+ dlm_lowcomms_put_msg(mh->msg);
+ /* mh is not part of rcu list in this case */
+ kfree(mh);
+ break;
+ case DLM_VERSION_3_2:
+ dlm_midcomms_commit_msg_3_2(mh);
+ srcu_read_unlock(&nodes_srcu, mh->idx);
+ break;
+ default:
+ srcu_read_unlock(&nodes_srcu, mh->idx);
+ WARN_ON(1);
+ break;
+ }
+}
+
+int dlm_midcomms_start(void)
+{
+ int i;
+
+ for (i = 0; i < CONN_HASH_SIZE; i++)
+ INIT_HLIST_HEAD(&node_hash[i]);
+
+ return dlm_lowcomms_start();
+}
+
+static void dlm_act_fin_ack_rcv(struct midcomms_node *node)
+{
+ spin_lock(&node->state_lock);
+ pr_debug("receive active fin ack from node %d with state %s\n",
+ node->nodeid, dlm_state_str(node->state));
+
+ switch (node->state) {
+ case DLM_FIN_WAIT1:
+ node->state = DLM_FIN_WAIT2;
+ pr_debug("switch node %d to state %s\n",
+ node->nodeid, dlm_state_str(node->state));
+ break;
+ case DLM_CLOSING:
+ midcomms_node_reset(node);
+ pr_debug("switch node %d to state %s\n",
+ node->nodeid, dlm_state_str(node->state));
+ wake_up(&node->shutdown_wait);
+ break;
+ case DLM_CLOSED:
+ /* not valid but somehow we got what we want */
+ wake_up(&node->shutdown_wait);
+ break;
+ default:
+ spin_unlock(&node->state_lock);
+ log_print("%s: unexpected state: %d\n",
+ __func__, node->state);
+ WARN_ON(1);
+ return;
+ }
+ spin_unlock(&node->state_lock);
+}
+
+void dlm_midcomms_add_member(int nodeid)
+{
+ struct midcomms_node *node;
+ int idx;
+
+ if (nodeid == dlm_our_nodeid())
+ return;
+
+ idx = srcu_read_lock(&nodes_srcu);
+ node = nodeid2node(nodeid, GFP_NOFS);
+ if (!node) {
+ srcu_read_unlock(&nodes_srcu, idx);
+ return;
+ }
+
+ spin_lock(&node->state_lock);
+ if (!node->users) {
+ pr_debug("receive add member from node %d with state %s\n",
+ node->nodeid, dlm_state_str(node->state));
+ switch (node->state) {
+ case DLM_ESTABLISHED:
+ break;
+ case DLM_CLOSED:
+ node->state = DLM_ESTABLISHED;
+ pr_debug("switch node %d to state %s\n",
+ node->nodeid, dlm_state_str(node->state));
+ break;
+ default:
+ /* some invalid state passive shutdown
+ * was failed, we try to reset and
+ * hope it will go on.
+ */
+ log_print("reset node %d because shutdown stucked",
+ node->nodeid);
+
+ midcomms_node_reset(node);
+ node->state = DLM_ESTABLISHED;
+ break;
+ }
+ }
+
+ node->users++;
+ pr_debug("users inc count %d\n", node->users);
+ spin_unlock(&node->state_lock);
+
+ srcu_read_unlock(&nodes_srcu, idx);
+}
+
+void dlm_midcomms_remove_member(int nodeid)
+{
+ struct midcomms_node *node;
+ int idx;
+
+ if (nodeid == dlm_our_nodeid())
+ return;
+
+ idx = srcu_read_lock(&nodes_srcu);
+ node = nodeid2node(nodeid, 0);
+ if (!node) {
+ srcu_read_unlock(&nodes_srcu, idx);
+ return;
+ }
+
+ spin_lock(&node->state_lock);
+ node->users--;
+ pr_debug("users dec count %d\n", node->users);
+
+ /* hitting users count to zero means the
+ * other side is running dlm_midcomms_stop()
+ * we meet us to have a clean disconnect.
+ */
+ if (node->users == 0) {
+ pr_debug("receive remove member from node %d with state %s\n",
+ node->nodeid, dlm_state_str(node->state));
+ switch (node->state) {
+ case DLM_ESTABLISHED:
+ break;
+ case DLM_CLOSE_WAIT:
+ /* passive shutdown DLM_LAST_ACK case 2 */
+ node->state = DLM_LAST_ACK;
+ spin_unlock(&node->state_lock);
+
+ pr_debug("switch node %d to state %s case 2\n",
+ node->nodeid, dlm_state_str(node->state));
+ goto send_fin;
+ case DLM_LAST_ACK:
+ /* probably receive fin caught it, do nothing */
+ break;
+ case DLM_CLOSED:
+ /* already gone, do nothing */
+ break;
+ default:
+ log_print("%s: unexpected state: %d\n",
+ __func__, node->state);
+ break;
+ }
+ }
+ spin_unlock(&node->state_lock);
+
+ srcu_read_unlock(&nodes_srcu, idx);
+ return;
+
+send_fin:
+ set_bit(DLM_NODE_FLAG_STOP_RX, &node->flags);
+ dlm_send_fin(node, dlm_pas_fin_ack_rcv);
+ srcu_read_unlock(&nodes_srcu, idx);
+}
+
+static void midcomms_node_release(struct rcu_head *rcu)
+{
+ struct midcomms_node *node = container_of(rcu, struct midcomms_node, rcu);
+
+ WARN_ON(atomic_read(&node->send_queue_cnt));
+ kfree(node);
+}
+
+static void midcomms_shutdown(struct midcomms_node *node)
+{
+ int ret;
+
+ /* old protocol, we don't wait for pending operations */
+ switch (node->version) {
+ case DLM_VERSION_3_2:
+ break;
+ default:
+ return;
+ }
+
+ spin_lock(&node->state_lock);
+ pr_debug("receive active shutdown for node %d with state %s\n",
+ node->nodeid, dlm_state_str(node->state));
+ switch (node->state) {
+ case DLM_ESTABLISHED:
+ node->state = DLM_FIN_WAIT1;
+ pr_debug("switch node %d to state %s case 2\n",
+ node->nodeid, dlm_state_str(node->state));
+ break;
+ case DLM_CLOSED:
+ /* we have what we want */
+ spin_unlock(&node->state_lock);
+ return;
+ default:
+ /* busy to enter DLM_FIN_WAIT1, wait until passive
+ * done in shutdown_wait to enter DLM_CLOSED.
+ */
+ break;
+ }
+ spin_unlock(&node->state_lock);
+
+ if (node->state == DLM_FIN_WAIT1) {
+ dlm_send_fin(node, dlm_act_fin_ack_rcv);
+
+ if (DLM_DEBUG_FENCE_TERMINATION)
+ msleep(5000);
+ }
+
+ /* wait for other side dlm + fin */
+ ret = wait_event_timeout(node->shutdown_wait,
+ node->state == DLM_CLOSED ||
+ test_bit(DLM_NODE_FLAG_CLOSE, &node->flags),
+ DLM_SHUTDOWN_TIMEOUT);
+ if (!ret || test_bit(DLM_NODE_FLAG_CLOSE, &node->flags)) {
+ pr_debug("active shutdown timed out for node %d with state %s\n",
+ node->nodeid, dlm_state_str(node->state));
+ midcomms_node_reset(node);
+ return;
+ }
+
+ pr_debug("active shutdown done for node %d with state %s\n",
+ node->nodeid, dlm_state_str(node->state));
+}
+
+void dlm_midcomms_shutdown(void)
+{
+ struct midcomms_node *node;
+ int i, idx;
+
+ mutex_lock(&close_lock);
+ idx = srcu_read_lock(&nodes_srcu);
+ for (i = 0; i < CONN_HASH_SIZE; i++) {
+ hlist_for_each_entry_rcu(node, &node_hash[i], hlist) {
+ midcomms_shutdown(node);
+
+ spin_lock(&nodes_lock);
+ hlist_del_rcu(&node->hlist);
+ spin_unlock(&nodes_lock);
+
+ call_srcu(&nodes_srcu, &node->rcu, midcomms_node_release);
+ }
+ }
+ srcu_read_unlock(&nodes_srcu, idx);
+ mutex_unlock(&close_lock);
+
+ dlm_lowcomms_shutdown();
+}
+
+int dlm_midcomms_close(int nodeid)
+{
+ struct midcomms_node *node;
+ int idx, ret;
+
+ if (nodeid == dlm_our_nodeid())
+ return 0;
+
+ idx = srcu_read_lock(&nodes_srcu);
+ /* Abort pending close/remove operation */
+ node = nodeid2node(nodeid, 0);
+ if (node) {
+ /* let shutdown waiters leave */
+ set_bit(DLM_NODE_FLAG_CLOSE, &node->flags);
+ wake_up(&node->shutdown_wait);
+ }
+ srcu_read_unlock(&nodes_srcu, idx);
+
+ synchronize_srcu(&nodes_srcu);
+
+ idx = srcu_read_lock(&nodes_srcu);
+ mutex_lock(&close_lock);
+ node = nodeid2node(nodeid, 0);
+ if (!node) {
+ mutex_unlock(&close_lock);
+ srcu_read_unlock(&nodes_srcu, idx);
+ return dlm_lowcomms_close(nodeid);
+ }
+
+ ret = dlm_lowcomms_close(nodeid);
+ spin_lock(&node->state_lock);
+ midcomms_node_reset(node);
+ spin_unlock(&node->state_lock);
+ srcu_read_unlock(&nodes_srcu, idx);
+ mutex_unlock(&close_lock);
+
+ return ret;
+}