diff options
Diffstat (limited to 'fs/dlm/lowcomms.c')
| -rw-r--r-- | fs/dlm/lowcomms.c | 1997 |
1 files changed, 1997 insertions, 0 deletions
diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c new file mode 100644 index 0000000000..32dbd1a828 --- /dev/null +++ b/fs/dlm/lowcomms.c @@ -0,0 +1,1997 @@ +// SPDX-License-Identifier: GPL-2.0-only +/****************************************************************************** +******************************************************************************* +** +** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved. +** Copyright (C) 2004-2009 Red Hat, Inc. All rights reserved. +** +** +******************************************************************************* +******************************************************************************/ + +/* + * lowcomms.c + * + * This is the "low-level" comms layer. + * + * It is responsible for sending/receiving messages + * from other nodes in the cluster. + * + * Cluster nodes are referred to by their nodeids. nodeids are + * simply 32 bit numbers to the locking module - if they need to + * be expanded for the cluster infrastructure then that is its + * responsibility. It is this layer's + * responsibility to resolve these into IP address or + * whatever it needs for inter-node communication. + * + * The comms level is two kernel threads that deal mainly with + * the receiving of messages from other nodes and passing them + * up to the mid-level comms layer (which understands the + * message format) for execution by the locking core, and + * a send thread which does all the setting up of connections + * to remote nodes and the sending of data. Threads are not allowed + * to send their own data because it may cause them to wait in times + * of high load. Also, this way, the sending thread can collect together + * messages bound for one node and send them in one block. + * + * lowcomms will choose to use either TCP or SCTP as its transport layer + * depending on the configuration variable 'protocol'. This should be set + * to 0 (default) for TCP or 1 for SCTP. It should be configured using a + * cluster-wide mechanism as it must be the same on all nodes of the cluster + * for the DLM to function. + * + */ + +#include <asm/ioctls.h> +#include <net/sock.h> +#include <net/tcp.h> +#include <linux/pagemap.h> +#include <linux/file.h> +#include <linux/mutex.h> +#include <linux/sctp.h> +#include <linux/slab.h> +#include <net/sctp/sctp.h> +#include <net/ipv6.h> + +#include <trace/events/dlm.h> +#include <trace/events/sock.h> + +#include "dlm_internal.h" +#include "lowcomms.h" +#include "midcomms.h" +#include "memory.h" +#include "config.h" + +#define DLM_SHUTDOWN_WAIT_TIMEOUT msecs_to_jiffies(5000) +#define NEEDED_RMEM (4*1024*1024) + +struct connection { + struct socket *sock; /* NULL if not connected */ + uint32_t nodeid; /* So we know who we are in the list */ + /* this semaphore is used to allow parallel recv/send in read + * lock mode. When we release a sock we need to held the write lock. + * + * However this is locking code and not nice. When we remove the + * othercon handling we can look into other mechanism to synchronize + * io handling to call sock_release() at the right time. + */ + struct rw_semaphore sock_lock; + unsigned long flags; +#define CF_APP_LIMITED 0 +#define CF_RECV_PENDING 1 +#define CF_SEND_PENDING 2 +#define CF_RECV_INTR 3 +#define CF_IO_STOP 4 +#define CF_IS_OTHERCON 5 + struct list_head writequeue; /* List of outgoing writequeue_entries */ + spinlock_t writequeue_lock; + int retries; + struct hlist_node list; + /* due some connect()/accept() races we currently have this cross over + * connection attempt second connection for one node. + * + * There is a solution to avoid the race by introducing a connect + * rule as e.g. our_nodeid > nodeid_to_connect who is allowed to + * connect. Otherside can connect but will only be considered that + * the other side wants to have a reconnect. + * + * However changing to this behaviour will break backwards compatible. + * In a DLM protocol major version upgrade we should remove this! + */ + struct connection *othercon; + struct work_struct rwork; /* receive worker */ + struct work_struct swork; /* send worker */ + wait_queue_head_t shutdown_wait; + unsigned char rx_leftover_buf[DLM_MAX_SOCKET_BUFSIZE]; + int rx_leftover; + int mark; + int addr_count; + int curr_addr_index; + struct sockaddr_storage addr[DLM_MAX_ADDR_COUNT]; + spinlock_t addrs_lock; + struct rcu_head rcu; +}; +#define sock2con(x) ((struct connection *)(x)->sk_user_data) + +struct listen_connection { + struct socket *sock; + struct work_struct rwork; +}; + +#define DLM_WQ_REMAIN_BYTES(e) (PAGE_SIZE - e->end) +#define DLM_WQ_LENGTH_BYTES(e) (e->end - e->offset) + +/* An entry waiting to be sent */ +struct writequeue_entry { + struct list_head list; + struct page *page; + int offset; + int len; + int end; + int users; + bool dirty; + struct connection *con; + struct list_head msgs; + struct kref ref; +}; + +struct dlm_msg { + struct writequeue_entry *entry; + struct dlm_msg *orig_msg; + bool retransmit; + void *ppc; + int len; + int idx; /* new()/commit() idx exchange */ + + struct list_head list; + struct kref ref; +}; + +struct processqueue_entry { + unsigned char *buf; + int nodeid; + int buflen; + + struct list_head list; +}; + +struct dlm_proto_ops { + bool try_new_addr; + const char *name; + int proto; + + int (*connect)(struct connection *con, struct socket *sock, + struct sockaddr *addr, int addr_len); + void (*sockopts)(struct socket *sock); + int (*bind)(struct socket *sock); + int (*listen_validate)(void); + void (*listen_sockopts)(struct socket *sock); + int (*listen_bind)(struct socket *sock); +}; + +static struct listen_sock_callbacks { + void (*sk_error_report)(struct sock *); + void (*sk_data_ready)(struct sock *); + void (*sk_state_change)(struct sock *); + void (*sk_write_space)(struct sock *); +} listen_sock; + +static struct listen_connection listen_con; +static struct sockaddr_storage dlm_local_addr[DLM_MAX_ADDR_COUNT]; +static int dlm_local_count; + +/* Work queues */ +static struct workqueue_struct *io_workqueue; +static struct workqueue_struct *process_workqueue; + +static struct hlist_head connection_hash[CONN_HASH_SIZE]; +static DEFINE_SPINLOCK(connections_lock); +DEFINE_STATIC_SRCU(connections_srcu); + +static const struct dlm_proto_ops *dlm_proto_ops; + +#define DLM_IO_SUCCESS 0 +#define DLM_IO_END 1 +#define DLM_IO_EOF 2 +#define DLM_IO_RESCHED 3 + +static void process_recv_sockets(struct work_struct *work); +static void process_send_sockets(struct work_struct *work); +static void process_dlm_messages(struct work_struct *work); + +static DECLARE_WORK(process_work, process_dlm_messages); +static DEFINE_SPINLOCK(processqueue_lock); +static bool process_dlm_messages_pending; +static LIST_HEAD(processqueue); + +bool dlm_lowcomms_is_running(void) +{ + return !!listen_con.sock; +} + +static void lowcomms_queue_swork(struct connection *con) +{ + assert_spin_locked(&con->writequeue_lock); + + if (!test_bit(CF_IO_STOP, &con->flags) && + !test_bit(CF_APP_LIMITED, &con->flags) && + !test_and_set_bit(CF_SEND_PENDING, &con->flags)) + queue_work(io_workqueue, &con->swork); +} + +static void lowcomms_queue_rwork(struct connection *con) +{ +#ifdef CONFIG_LOCKDEP + WARN_ON_ONCE(!lockdep_sock_is_held(con->sock->sk)); +#endif + + if (!test_bit(CF_IO_STOP, &con->flags) && + !test_and_set_bit(CF_RECV_PENDING, &con->flags)) + queue_work(io_workqueue, &con->rwork); +} + +static void writequeue_entry_ctor(void *data) +{ + struct writequeue_entry *entry = data; + + INIT_LIST_HEAD(&entry->msgs); +} + +struct kmem_cache *dlm_lowcomms_writequeue_cache_create(void) +{ + return kmem_cache_create("dlm_writequeue", sizeof(struct writequeue_entry), + 0, 0, writequeue_entry_ctor); +} + +struct kmem_cache *dlm_lowcomms_msg_cache_create(void) +{ + return kmem_cache_create("dlm_msg", sizeof(struct dlm_msg), 0, 0, NULL); +} + +/* need to held writequeue_lock */ +static struct writequeue_entry *con_next_wq(struct connection *con) +{ + struct writequeue_entry *e; + + e = list_first_entry_or_null(&con->writequeue, struct writequeue_entry, + list); + /* if len is zero nothing is to send, if there are users filling + * buffers we wait until the users are done so we can send more. + */ + if (!e || e->users || e->len == 0) + return NULL; + + return e; +} + +static struct connection *__find_con(int nodeid, int r) +{ + struct connection *con; + + hlist_for_each_entry_rcu(con, &connection_hash[r], list) { + if (con->nodeid == nodeid) + return con; + } + + return NULL; +} + +static void dlm_con_init(struct connection *con, int nodeid) +{ + con->nodeid = nodeid; + init_rwsem(&con->sock_lock); + INIT_LIST_HEAD(&con->writequeue); + spin_lock_init(&con->writequeue_lock); + INIT_WORK(&con->swork, process_send_sockets); + INIT_WORK(&con->rwork, process_recv_sockets); + spin_lock_init(&con->addrs_lock); + init_waitqueue_head(&con->shutdown_wait); +} + +/* + * If 'allocation' is zero then we don't attempt to create a new + * connection structure for this node. + */ +static struct connection *nodeid2con(int nodeid, gfp_t alloc) +{ + struct connection *con, *tmp; + int r; + + r = nodeid_hash(nodeid); + con = __find_con(nodeid, r); + if (con || !alloc) + return con; + + con = kzalloc(sizeof(*con), alloc); + if (!con) + return NULL; + + dlm_con_init(con, nodeid); + + spin_lock(&connections_lock); + /* Because multiple workqueues/threads calls this function it can + * race on multiple cpu's. Instead of locking hot path __find_con() + * we just check in rare cases of recently added nodes again + * under protection of connections_lock. If this is the case we + * abort our connection creation and return the existing connection. + */ + tmp = __find_con(nodeid, r); + if (tmp) { + spin_unlock(&connections_lock); + kfree(con); + return tmp; + } + + hlist_add_head_rcu(&con->list, &connection_hash[r]); + spin_unlock(&connections_lock); + + return con; +} + +static int addr_compare(const struct sockaddr_storage *x, + const struct sockaddr_storage *y) +{ + switch (x->ss_family) { + case AF_INET: { + struct sockaddr_in *sinx = (struct sockaddr_in *)x; + struct sockaddr_in *siny = (struct sockaddr_in *)y; + if (sinx->sin_addr.s_addr != siny->sin_addr.s_addr) + return 0; + if (sinx->sin_port != siny->sin_port) + return 0; + break; + } + case AF_INET6: { + struct sockaddr_in6 *sinx = (struct sockaddr_in6 *)x; + struct sockaddr_in6 *siny = (struct sockaddr_in6 *)y; + if (!ipv6_addr_equal(&sinx->sin6_addr, &siny->sin6_addr)) + return 0; + if (sinx->sin6_port != siny->sin6_port) + return 0; + break; + } + default: + return 0; + } + return 1; +} + +static int nodeid_to_addr(int nodeid, struct sockaddr_storage *sas_out, + struct sockaddr *sa_out, bool try_new_addr, + unsigned int *mark) +{ + struct sockaddr_storage sas; + struct connection *con; + int idx; + + if (!dlm_local_count) + return -1; + + idx = srcu_read_lock(&connections_srcu); + con = nodeid2con(nodeid, 0); + if (!con) { + srcu_read_unlock(&connections_srcu, idx); + return -ENOENT; + } + + spin_lock(&con->addrs_lock); + if (!con->addr_count) { + spin_unlock(&con->addrs_lock); + srcu_read_unlock(&connections_srcu, idx); + return -ENOENT; + } + + memcpy(&sas, &con->addr[con->curr_addr_index], + sizeof(struct sockaddr_storage)); + + if (try_new_addr) { + con->curr_addr_index++; + if (con->curr_addr_index == con->addr_count) + con->curr_addr_index = 0; + } + + *mark = con->mark; + spin_unlock(&con->addrs_lock); + + if (sas_out) + memcpy(sas_out, &sas, sizeof(struct sockaddr_storage)); + + if (!sa_out) { + srcu_read_unlock(&connections_srcu, idx); + return 0; + } + + if (dlm_local_addr[0].ss_family == AF_INET) { + struct sockaddr_in *in4 = (struct sockaddr_in *) &sas; + struct sockaddr_in *ret4 = (struct sockaddr_in *) sa_out; + ret4->sin_addr.s_addr = in4->sin_addr.s_addr; + } else { + struct sockaddr_in6 *in6 = (struct sockaddr_in6 *) &sas; + struct sockaddr_in6 *ret6 = (struct sockaddr_in6 *) sa_out; + ret6->sin6_addr = in6->sin6_addr; + } + + srcu_read_unlock(&connections_srcu, idx); + return 0; +} + +static int addr_to_nodeid(struct sockaddr_storage *addr, int *nodeid, + unsigned int *mark) +{ + struct connection *con; + int i, idx, addr_i; + + idx = srcu_read_lock(&connections_srcu); + for (i = 0; i < CONN_HASH_SIZE; i++) { + hlist_for_each_entry_rcu(con, &connection_hash[i], list) { + WARN_ON_ONCE(!con->addr_count); + + spin_lock(&con->addrs_lock); + for (addr_i = 0; addr_i < con->addr_count; addr_i++) { + if (addr_compare(&con->addr[addr_i], addr)) { + *nodeid = con->nodeid; + *mark = con->mark; + spin_unlock(&con->addrs_lock); + srcu_read_unlock(&connections_srcu, idx); + return 0; + } + } + spin_unlock(&con->addrs_lock); + } + } + srcu_read_unlock(&connections_srcu, idx); + + return -ENOENT; +} + +static bool dlm_lowcomms_con_has_addr(const struct connection *con, + const struct sockaddr_storage *addr) +{ + int i; + + for (i = 0; i < con->addr_count; i++) { + if (addr_compare(&con->addr[i], addr)) + return true; + } + + return false; +} + +int dlm_lowcomms_addr(int nodeid, struct sockaddr_storage *addr, int len) +{ + struct connection *con; + bool ret, idx; + + idx = srcu_read_lock(&connections_srcu); + con = nodeid2con(nodeid, GFP_NOFS); + if (!con) { + srcu_read_unlock(&connections_srcu, idx); + return -ENOMEM; + } + + spin_lock(&con->addrs_lock); + if (!con->addr_count) { + memcpy(&con->addr[0], addr, sizeof(*addr)); + con->addr_count = 1; + con->mark = dlm_config.ci_mark; + spin_unlock(&con->addrs_lock); + srcu_read_unlock(&connections_srcu, idx); + return 0; + } + + ret = dlm_lowcomms_con_has_addr(con, addr); + if (ret) { + spin_unlock(&con->addrs_lock); + srcu_read_unlock(&connections_srcu, idx); + return -EEXIST; + } + + if (con->addr_count >= DLM_MAX_ADDR_COUNT) { + spin_unlock(&con->addrs_lock); + srcu_read_unlock(&connections_srcu, idx); + return -ENOSPC; + } + + memcpy(&con->addr[con->addr_count++], addr, sizeof(*addr)); + srcu_read_unlock(&connections_srcu, idx); + spin_unlock(&con->addrs_lock); + return 0; +} + +/* Data available on socket or listen socket received a connect */ +static void lowcomms_data_ready(struct sock *sk) +{ + struct connection *con = sock2con(sk); + + trace_sk_data_ready(sk); + + set_bit(CF_RECV_INTR, &con->flags); + lowcomms_queue_rwork(con); +} + +static void lowcomms_write_space(struct sock *sk) +{ + struct connection *con = sock2con(sk); + + clear_bit(SOCK_NOSPACE, &con->sock->flags); + + spin_lock_bh(&con->writequeue_lock); + if (test_and_clear_bit(CF_APP_LIMITED, &con->flags)) { + con->sock->sk->sk_write_pending--; + clear_bit(SOCKWQ_ASYNC_NOSPACE, &con->sock->flags); + } + + lowcomms_queue_swork(con); + spin_unlock_bh(&con->writequeue_lock); +} + +static void lowcomms_state_change(struct sock *sk) +{ + /* SCTP layer is not calling sk_data_ready when the connection + * is done, so we catch the signal through here. + */ + if (sk->sk_shutdown == RCV_SHUTDOWN) + lowcomms_data_ready(sk); +} + +static void lowcomms_listen_data_ready(struct sock *sk) +{ + trace_sk_data_ready(sk); + + queue_work(io_workqueue, &listen_con.rwork); +} + +int dlm_lowcomms_connect_node(int nodeid) +{ + struct connection *con; + int idx; + + idx = srcu_read_lock(&connections_srcu); + con = nodeid2con(nodeid, 0); + if (WARN_ON_ONCE(!con)) { + srcu_read_unlock(&connections_srcu, idx); + return -ENOENT; + } + + down_read(&con->sock_lock); + if (!con->sock) { + spin_lock_bh(&con->writequeue_lock); + lowcomms_queue_swork(con); + spin_unlock_bh(&con->writequeue_lock); + } + up_read(&con->sock_lock); + srcu_read_unlock(&connections_srcu, idx); + + cond_resched(); + return 0; +} + +int dlm_lowcomms_nodes_set_mark(int nodeid, unsigned int mark) +{ + struct connection *con; + int idx; + + idx = srcu_read_lock(&connections_srcu); + con = nodeid2con(nodeid, 0); + if (!con) { + srcu_read_unlock(&connections_srcu, idx); + return -ENOENT; + } + + spin_lock(&con->addrs_lock); + con->mark = mark; + spin_unlock(&con->addrs_lock); + srcu_read_unlock(&connections_srcu, idx); + return 0; +} + +static void lowcomms_error_report(struct sock *sk) +{ + struct connection *con = sock2con(sk); + struct inet_sock *inet; + + inet = inet_sk(sk); + switch (sk->sk_family) { + case AF_INET: + printk_ratelimited(KERN_ERR "dlm: node %d: socket error " + "sending to node %d at %pI4, dport %d, " + "sk_err=%d/%d\n", dlm_our_nodeid(), + con->nodeid, &inet->inet_daddr, + ntohs(inet->inet_dport), sk->sk_err, + READ_ONCE(sk->sk_err_soft)); + break; +#if IS_ENABLED(CONFIG_IPV6) + case AF_INET6: + printk_ratelimited(KERN_ERR "dlm: node %d: socket error " + "sending to node %d at %pI6c, " + "dport %d, sk_err=%d/%d\n", dlm_our_nodeid(), + con->nodeid, &sk->sk_v6_daddr, + ntohs(inet->inet_dport), sk->sk_err, + READ_ONCE(sk->sk_err_soft)); + break; +#endif + default: + printk_ratelimited(KERN_ERR "dlm: node %d: socket error " + "invalid socket family %d set, " + "sk_err=%d/%d\n", dlm_our_nodeid(), + sk->sk_family, sk->sk_err, + READ_ONCE(sk->sk_err_soft)); + break; + } + + dlm_midcomms_unack_msg_resend(con->nodeid); + + listen_sock.sk_error_report(sk); +} + +static void restore_callbacks(struct sock *sk) +{ +#ifdef CONFIG_LOCKDEP + WARN_ON_ONCE(!lockdep_sock_is_held(sk)); +#endif + + sk->sk_user_data = NULL; + sk->sk_data_ready = listen_sock.sk_data_ready; + sk->sk_state_change = listen_sock.sk_state_change; + sk->sk_write_space = listen_sock.sk_write_space; + sk->sk_error_report = listen_sock.sk_error_report; +} + +/* Make a socket active */ +static void add_sock(struct socket *sock, struct connection *con) +{ + struct sock *sk = sock->sk; + + lock_sock(sk); + con->sock = sock; + + sk->sk_user_data = con; + sk->sk_data_ready = lowcomms_data_ready; + sk->sk_write_space = lowcomms_write_space; + if (dlm_config.ci_protocol == DLM_PROTO_SCTP) + sk->sk_state_change = lowcomms_state_change; + sk->sk_allocation = GFP_NOFS; + sk->sk_use_task_frag = false; + sk->sk_error_report = lowcomms_error_report; + release_sock(sk); +} + +/* Add the port number to an IPv6 or 4 sockaddr and return the address + length */ +static void make_sockaddr(struct sockaddr_storage *saddr, uint16_t port, + int *addr_len) +{ + saddr->ss_family = dlm_local_addr[0].ss_family; + if (saddr->ss_family == AF_INET) { + struct sockaddr_in *in4_addr = (struct sockaddr_in *)saddr; + in4_addr->sin_port = cpu_to_be16(port); + *addr_len = sizeof(struct sockaddr_in); + memset(&in4_addr->sin_zero, 0, sizeof(in4_addr->sin_zero)); + } else { + struct sockaddr_in6 *in6_addr = (struct sockaddr_in6 *)saddr; + in6_addr->sin6_port = cpu_to_be16(port); + *addr_len = sizeof(struct sockaddr_in6); + } + memset((char *)saddr + *addr_len, 0, sizeof(struct sockaddr_storage) - *addr_len); +} + +static void dlm_page_release(struct kref *kref) +{ + struct writequeue_entry *e = container_of(kref, struct writequeue_entry, + ref); + + __free_page(e->page); + dlm_free_writequeue(e); +} + +static void dlm_msg_release(struct kref *kref) +{ + struct dlm_msg *msg = container_of(kref, struct dlm_msg, ref); + + kref_put(&msg->entry->ref, dlm_page_release); + dlm_free_msg(msg); +} + +static void free_entry(struct writequeue_entry *e) +{ + struct dlm_msg *msg, *tmp; + + list_for_each_entry_safe(msg, tmp, &e->msgs, list) { + if (msg->orig_msg) { + msg->orig_msg->retransmit = false; + kref_put(&msg->orig_msg->ref, dlm_msg_release); + } + + list_del(&msg->list); + kref_put(&msg->ref, dlm_msg_release); + } + + list_del(&e->list); + kref_put(&e->ref, dlm_page_release); +} + +static void dlm_close_sock(struct socket **sock) +{ + lock_sock((*sock)->sk); + restore_callbacks((*sock)->sk); + release_sock((*sock)->sk); + + sock_release(*sock); + *sock = NULL; +} + +static void allow_connection_io(struct connection *con) +{ + if (con->othercon) + clear_bit(CF_IO_STOP, &con->othercon->flags); + clear_bit(CF_IO_STOP, &con->flags); +} + +static void stop_connection_io(struct connection *con) +{ + if (con->othercon) + stop_connection_io(con->othercon); + + spin_lock_bh(&con->writequeue_lock); + set_bit(CF_IO_STOP, &con->flags); + spin_unlock_bh(&con->writequeue_lock); + + down_write(&con->sock_lock); + if (con->sock) { + lock_sock(con->sock->sk); + restore_callbacks(con->sock->sk); + release_sock(con->sock->sk); + } + up_write(&con->sock_lock); + + cancel_work_sync(&con->swork); + cancel_work_sync(&con->rwork); +} + +/* Close a remote connection and tidy up */ +static void close_connection(struct connection *con, bool and_other) +{ + struct writequeue_entry *e; + + if (con->othercon && and_other) + close_connection(con->othercon, false); + + down_write(&con->sock_lock); + if (!con->sock) { + up_write(&con->sock_lock); + return; + } + + dlm_close_sock(&con->sock); + + /* if we send a writequeue entry only a half way, we drop the + * whole entry because reconnection and that we not start of the + * middle of a msg which will confuse the other end. + * + * we can always drop messages because retransmits, but what we + * cannot allow is to transmit half messages which may be processed + * at the other side. + * + * our policy is to start on a clean state when disconnects, we don't + * know what's send/received on transport layer in this case. + */ + spin_lock_bh(&con->writequeue_lock); + if (!list_empty(&con->writequeue)) { + e = list_first_entry(&con->writequeue, struct writequeue_entry, + list); + if (e->dirty) + free_entry(e); + } + spin_unlock_bh(&con->writequeue_lock); + + con->rx_leftover = 0; + con->retries = 0; + clear_bit(CF_APP_LIMITED, &con->flags); + clear_bit(CF_RECV_PENDING, &con->flags); + clear_bit(CF_SEND_PENDING, &con->flags); + up_write(&con->sock_lock); +} + +static void shutdown_connection(struct connection *con, bool and_other) +{ + int ret; + + if (con->othercon && and_other) + shutdown_connection(con->othercon, false); + + flush_workqueue(io_workqueue); + down_read(&con->sock_lock); + /* nothing to shutdown */ + if (!con->sock) { + up_read(&con->sock_lock); + return; + } + + ret = kernel_sock_shutdown(con->sock, SHUT_WR); + up_read(&con->sock_lock); + if (ret) { + log_print("Connection %p failed to shutdown: %d will force close", + con, ret); + goto force_close; + } else { + ret = wait_event_timeout(con->shutdown_wait, !con->sock, + DLM_SHUTDOWN_WAIT_TIMEOUT); + if (ret == 0) { + log_print("Connection %p shutdown timed out, will force close", + con); + goto force_close; + } + } + + return; + +force_close: + close_connection(con, false); +} + +static struct processqueue_entry *new_processqueue_entry(int nodeid, + int buflen) +{ + struct processqueue_entry *pentry; + + pentry = kmalloc(sizeof(*pentry), GFP_NOFS); + if (!pentry) + return NULL; + + pentry->buf = kmalloc(buflen, GFP_NOFS); + if (!pentry->buf) { + kfree(pentry); + return NULL; + } + + pentry->nodeid = nodeid; + return pentry; +} + +static void free_processqueue_entry(struct processqueue_entry *pentry) +{ + kfree(pentry->buf); + kfree(pentry); +} + +struct dlm_processed_nodes { + int nodeid; + + struct list_head list; +}; + +static void process_dlm_messages(struct work_struct *work) +{ + struct processqueue_entry *pentry; + + spin_lock(&processqueue_lock); + pentry = list_first_entry_or_null(&processqueue, + struct processqueue_entry, list); + if (WARN_ON_ONCE(!pentry)) { + process_dlm_messages_pending = false; + spin_unlock(&processqueue_lock); + return; + } + + list_del(&pentry->list); + spin_unlock(&processqueue_lock); + + for (;;) { + dlm_process_incoming_buffer(pentry->nodeid, pentry->buf, + pentry->buflen); + free_processqueue_entry(pentry); + + spin_lock(&processqueue_lock); + pentry = list_first_entry_or_null(&processqueue, + struct processqueue_entry, list); + if (!pentry) { + process_dlm_messages_pending = false; + spin_unlock(&processqueue_lock); + break; + } + + list_del(&pentry->list); + spin_unlock(&processqueue_lock); + } +} + +/* Data received from remote end */ +static int receive_from_sock(struct connection *con, int buflen) +{ + struct processqueue_entry *pentry; + int ret, buflen_real; + struct msghdr msg; + struct kvec iov; + + pentry = new_processqueue_entry(con->nodeid, buflen); + if (!pentry) + return DLM_IO_RESCHED; + + memcpy(pentry->buf, con->rx_leftover_buf, con->rx_leftover); + + /* calculate new buffer parameter regarding last receive and + * possible leftover bytes + */ + iov.iov_base = pentry->buf + con->rx_leftover; + iov.iov_len = buflen - con->rx_leftover; + + memset(&msg, 0, sizeof(msg)); + msg.msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL; + clear_bit(CF_RECV_INTR, &con->flags); +again: + ret = kernel_recvmsg(con->sock, &msg, &iov, 1, iov.iov_len, + msg.msg_flags); + trace_dlm_recv(con->nodeid, ret); + if (ret == -EAGAIN) { + lock_sock(con->sock->sk); + if (test_and_clear_bit(CF_RECV_INTR, &con->flags)) { + release_sock(con->sock->sk); + goto again; + } + + clear_bit(CF_RECV_PENDING, &con->flags); + release_sock(con->sock->sk); + free_processqueue_entry(pentry); + return DLM_IO_END; + } else if (ret == 0) { + /* close will clear CF_RECV_PENDING */ + free_processqueue_entry(pentry); + return DLM_IO_EOF; + } else if (ret < 0) { + free_processqueue_entry(pentry); + return ret; + } + + /* new buflen according readed bytes and leftover from last receive */ + buflen_real = ret + con->rx_leftover; + ret = dlm_validate_incoming_buffer(con->nodeid, pentry->buf, + buflen_real); + if (ret < 0) { + free_processqueue_entry(pentry); + return ret; + } + + pentry->buflen = ret; + + /* calculate leftover bytes from process and put it into begin of + * the receive buffer, so next receive we have the full message + * at the start address of the receive buffer. + */ + con->rx_leftover = buflen_real - ret; + memmove(con->rx_leftover_buf, pentry->buf + ret, + con->rx_leftover); + + spin_lock(&processqueue_lock); + list_add_tail(&pentry->list, &processqueue); + if (!process_dlm_messages_pending) { + process_dlm_messages_pending = true; + queue_work(process_workqueue, &process_work); + } + spin_unlock(&processqueue_lock); + + return DLM_IO_SUCCESS; +} + +/* Listening socket is busy, accept a connection */ +static int accept_from_sock(void) +{ + struct sockaddr_storage peeraddr; + int len, idx, result, nodeid; + struct connection *newcon; + struct socket *newsock; + unsigned int mark; + + result = kernel_accept(listen_con.sock, &newsock, O_NONBLOCK); + if (result == -EAGAIN) + return DLM_IO_END; + else if (result < 0) + goto accept_err; + + /* Get the connected socket's peer */ + memset(&peeraddr, 0, sizeof(peeraddr)); + len = newsock->ops->getname(newsock, (struct sockaddr *)&peeraddr, 2); + if (len < 0) { + result = -ECONNABORTED; + goto accept_err; + } + + /* Get the new node's NODEID */ + make_sockaddr(&peeraddr, 0, &len); + if (addr_to_nodeid(&peeraddr, &nodeid, &mark)) { + switch (peeraddr.ss_family) { + case AF_INET: { + struct sockaddr_in *sin = (struct sockaddr_in *)&peeraddr; + + log_print("connect from non cluster IPv4 node %pI4", + &sin->sin_addr); + break; + } +#if IS_ENABLED(CONFIG_IPV6) + case AF_INET6: { + struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&peeraddr; + + log_print("connect from non cluster IPv6 node %pI6c", + &sin6->sin6_addr); + break; + } +#endif + default: + log_print("invalid family from non cluster node"); + break; + } + + sock_release(newsock); + return -1; + } + + log_print("got connection from %d", nodeid); + + /* Check to see if we already have a connection to this node. This + * could happen if the two nodes initiate a connection at roughly + * the same time and the connections cross on the wire. + * In this case we store the incoming one in "othercon" + */ + idx = srcu_read_lock(&connections_srcu); + newcon = nodeid2con(nodeid, 0); + if (WARN_ON_ONCE(!newcon)) { + srcu_read_unlock(&connections_srcu, idx); + result = -ENOENT; + goto accept_err; + } + + sock_set_mark(newsock->sk, mark); + + down_write(&newcon->sock_lock); + if (newcon->sock) { + struct connection *othercon = newcon->othercon; + + if (!othercon) { + othercon = kzalloc(sizeof(*othercon), GFP_NOFS); + if (!othercon) { + log_print("failed to allocate incoming socket"); + up_write(&newcon->sock_lock); + srcu_read_unlock(&connections_srcu, idx); + result = -ENOMEM; + goto accept_err; + } + + dlm_con_init(othercon, nodeid); + lockdep_set_subclass(&othercon->sock_lock, 1); + newcon->othercon = othercon; + set_bit(CF_IS_OTHERCON, &othercon->flags); + } else { + /* close other sock con if we have something new */ + close_connection(othercon, false); + } + + down_write(&othercon->sock_lock); + add_sock(newsock, othercon); + + /* check if we receved something while adding */ + lock_sock(othercon->sock->sk); + lowcomms_queue_rwork(othercon); + release_sock(othercon->sock->sk); + up_write(&othercon->sock_lock); + } + else { + /* accept copies the sk after we've saved the callbacks, so we + don't want to save them a second time or comm errors will + result in calling sk_error_report recursively. */ + add_sock(newsock, newcon); + + /* check if we receved something while adding */ + lock_sock(newcon->sock->sk); + lowcomms_queue_rwork(newcon); + release_sock(newcon->sock->sk); + } + up_write(&newcon->sock_lock); + srcu_read_unlock(&connections_srcu, idx); + + return DLM_IO_SUCCESS; + +accept_err: + if (newsock) + sock_release(newsock); + + return result; +} + +/* + * writequeue_entry_complete - try to delete and free write queue entry + * @e: write queue entry to try to delete + * @completed: bytes completed + * + * writequeue_lock must be held. + */ +static void writequeue_entry_complete(struct writequeue_entry *e, int completed) +{ + e->offset += completed; + e->len -= completed; + /* signal that page was half way transmitted */ + e->dirty = true; + + if (e->len == 0 && e->users == 0) + free_entry(e); +} + +/* + * sctp_bind_addrs - bind a SCTP socket to all our addresses + */ +static int sctp_bind_addrs(struct socket *sock, uint16_t port) +{ + struct sockaddr_storage localaddr; + struct sockaddr *addr = (struct sockaddr *)&localaddr; + int i, addr_len, result = 0; + + for (i = 0; i < dlm_local_count; i++) { + memcpy(&localaddr, &dlm_local_addr[i], sizeof(localaddr)); + make_sockaddr(&localaddr, port, &addr_len); + + if (!i) + result = kernel_bind(sock, addr, addr_len); + else + result = sock_bind_add(sock->sk, addr, addr_len); + + if (result < 0) { + log_print("Can't bind to %d addr number %d, %d.\n", + port, i + 1, result); + break; + } + } + return result; +} + +/* Get local addresses */ +static void init_local(void) +{ + struct sockaddr_storage sas; + int i; + + dlm_local_count = 0; + for (i = 0; i < DLM_MAX_ADDR_COUNT; i++) { + if (dlm_our_addr(&sas, i)) + break; + + memcpy(&dlm_local_addr[dlm_local_count++], &sas, sizeof(sas)); + } +} + +static struct writequeue_entry *new_writequeue_entry(struct connection *con) +{ + struct writequeue_entry *entry; + + entry = dlm_allocate_writequeue(); + if (!entry) + return NULL; + + entry->page = alloc_page(GFP_ATOMIC | __GFP_ZERO); + if (!entry->page) { + dlm_free_writequeue(entry); + return NULL; + } + + entry->offset = 0; + entry->len = 0; + entry->end = 0; + entry->dirty = false; + entry->con = con; + entry->users = 1; + kref_init(&entry->ref); + return entry; +} + +static struct writequeue_entry *new_wq_entry(struct connection *con, int len, + char **ppc, void (*cb)(void *data), + void *data) +{ + struct writequeue_entry *e; + + spin_lock_bh(&con->writequeue_lock); + if (!list_empty(&con->writequeue)) { + e = list_last_entry(&con->writequeue, struct writequeue_entry, list); + if (DLM_WQ_REMAIN_BYTES(e) >= len) { + kref_get(&e->ref); + + *ppc = page_address(e->page) + e->end; + if (cb) + cb(data); + + e->end += len; + e->users++; + goto out; + } + } + + e = new_writequeue_entry(con); + if (!e) + goto out; + + kref_get(&e->ref); + *ppc = page_address(e->page); + e->end += len; + if (cb) + cb(data); + + list_add_tail(&e->list, &con->writequeue); + +out: + spin_unlock_bh(&con->writequeue_lock); + return e; +}; + +static struct dlm_msg *dlm_lowcomms_new_msg_con(struct connection *con, int len, + gfp_t allocation, char **ppc, + void (*cb)(void *data), + void *data) +{ + struct writequeue_entry *e; + struct dlm_msg *msg; + + msg = dlm_allocate_msg(allocation); + if (!msg) + return NULL; + + kref_init(&msg->ref); + + e = new_wq_entry(con, len, ppc, cb, data); + if (!e) { + dlm_free_msg(msg); + return NULL; + } + + msg->retransmit = false; + msg->orig_msg = NULL; + msg->ppc = *ppc; + msg->len = len; + msg->entry = e; + + return msg; +} + +/* avoid false positive for nodes_srcu, unlock happens in + * dlm_lowcomms_commit_msg which is a must call if success + */ +#ifndef __CHECKER__ +struct dlm_msg *dlm_lowcomms_new_msg(int nodeid, int len, gfp_t allocation, + char **ppc, void (*cb)(void *data), + void *data) +{ + struct connection *con; + struct dlm_msg *msg; + int idx; + + if (len > DLM_MAX_SOCKET_BUFSIZE || + len < sizeof(struct dlm_header)) { + BUILD_BUG_ON(PAGE_SIZE < DLM_MAX_SOCKET_BUFSIZE); + log_print("failed to allocate a buffer of size %d", len); + WARN_ON_ONCE(1); + return NULL; + } + + idx = srcu_read_lock(&connections_srcu); + con = nodeid2con(nodeid, 0); + if (WARN_ON_ONCE(!con)) { + srcu_read_unlock(&connections_srcu, idx); + return NULL; + } + + msg = dlm_lowcomms_new_msg_con(con, len, allocation, ppc, cb, data); + if (!msg) { + srcu_read_unlock(&connections_srcu, idx); + return NULL; + } + + /* for dlm_lowcomms_commit_msg() */ + kref_get(&msg->ref); + /* we assume if successful commit must called */ + msg->idx = idx; + return msg; +} +#endif + +static void _dlm_lowcomms_commit_msg(struct dlm_msg *msg) +{ + struct writequeue_entry *e = msg->entry; + struct connection *con = e->con; + int users; + + spin_lock_bh(&con->writequeue_lock); + kref_get(&msg->ref); + list_add(&msg->list, &e->msgs); + + users = --e->users; + if (users) + goto out; + + e->len = DLM_WQ_LENGTH_BYTES(e); + + lowcomms_queue_swork(con); + +out: + spin_unlock_bh(&con->writequeue_lock); + return; +} + +/* avoid false positive for nodes_srcu, lock was happen in + * dlm_lowcomms_new_msg + */ +#ifndef __CHECKER__ +void dlm_lowcomms_commit_msg(struct dlm_msg *msg) +{ + _dlm_lowcomms_commit_msg(msg); + srcu_read_unlock(&connections_srcu, msg->idx); + /* because dlm_lowcomms_new_msg() */ + kref_put(&msg->ref, dlm_msg_release); +} +#endif + +void dlm_lowcomms_put_msg(struct dlm_msg *msg) +{ + kref_put(&msg->ref, dlm_msg_release); +} + +/* does not held connections_srcu, usage lowcomms_error_report only */ +int dlm_lowcomms_resend_msg(struct dlm_msg *msg) +{ + struct dlm_msg *msg_resend; + char *ppc; + + if (msg->retransmit) + return 1; + + msg_resend = dlm_lowcomms_new_msg_con(msg->entry->con, msg->len, + GFP_ATOMIC, &ppc, NULL, NULL); + if (!msg_resend) + return -ENOMEM; + + msg->retransmit = true; + kref_get(&msg->ref); + msg_resend->orig_msg = msg; + + memcpy(ppc, msg->ppc, msg->len); + _dlm_lowcomms_commit_msg(msg_resend); + dlm_lowcomms_put_msg(msg_resend); + + return 0; +} + +/* Send a message */ +static int send_to_sock(struct connection *con) +{ + struct writequeue_entry *e; + struct bio_vec bvec; + struct msghdr msg = { + .msg_flags = MSG_SPLICE_PAGES | MSG_DONTWAIT | MSG_NOSIGNAL, + }; + int len, offset, ret; + + spin_lock_bh(&con->writequeue_lock); + e = con_next_wq(con); + if (!e) { + clear_bit(CF_SEND_PENDING, &con->flags); + spin_unlock_bh(&con->writequeue_lock); + return DLM_IO_END; + } + + len = e->len; + offset = e->offset; + WARN_ON_ONCE(len == 0 && e->users == 0); + spin_unlock_bh(&con->writequeue_lock); + + bvec_set_page(&bvec, e->page, len, offset); + iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, &bvec, 1, len); + ret = sock_sendmsg(con->sock, &msg); + trace_dlm_send(con->nodeid, ret); + if (ret == -EAGAIN || ret == 0) { + lock_sock(con->sock->sk); + spin_lock_bh(&con->writequeue_lock); + if (test_bit(SOCKWQ_ASYNC_NOSPACE, &con->sock->flags) && + !test_and_set_bit(CF_APP_LIMITED, &con->flags)) { + /* Notify TCP that we're limited by the + * application window size. + */ + set_bit(SOCK_NOSPACE, &con->sock->sk->sk_socket->flags); + con->sock->sk->sk_write_pending++; + + clear_bit(CF_SEND_PENDING, &con->flags); + spin_unlock_bh(&con->writequeue_lock); + release_sock(con->sock->sk); + + /* wait for write_space() event */ + return DLM_IO_END; + } + spin_unlock_bh(&con->writequeue_lock); + release_sock(con->sock->sk); + + return DLM_IO_RESCHED; + } else if (ret < 0) { + return ret; + } + + spin_lock_bh(&con->writequeue_lock); + writequeue_entry_complete(e, ret); + spin_unlock_bh(&con->writequeue_lock); + + return DLM_IO_SUCCESS; +} + +static void clean_one_writequeue(struct connection *con) +{ + struct writequeue_entry *e, *safe; + + spin_lock_bh(&con->writequeue_lock); + list_for_each_entry_safe(e, safe, &con->writequeue, list) { + free_entry(e); + } + spin_unlock_bh(&con->writequeue_lock); +} + +static void connection_release(struct rcu_head *rcu) +{ + struct connection *con = container_of(rcu, struct connection, rcu); + + WARN_ON_ONCE(!list_empty(&con->writequeue)); + WARN_ON_ONCE(con->sock); + kfree(con); +} + +/* Called from recovery when it knows that a node has + left the cluster */ +int dlm_lowcomms_close(int nodeid) +{ + struct connection *con; + int idx; + + log_print("closing connection to node %d", nodeid); + + idx = srcu_read_lock(&connections_srcu); + con = nodeid2con(nodeid, 0); + if (WARN_ON_ONCE(!con)) { + srcu_read_unlock(&connections_srcu, idx); + return -ENOENT; + } + + stop_connection_io(con); + log_print("io handling for node: %d stopped", nodeid); + close_connection(con, true); + + spin_lock(&connections_lock); + hlist_del_rcu(&con->list); + spin_unlock(&connections_lock); + + clean_one_writequeue(con); + call_srcu(&connections_srcu, &con->rcu, connection_release); + if (con->othercon) { + clean_one_writequeue(con->othercon); + call_srcu(&connections_srcu, &con->othercon->rcu, connection_release); + } + srcu_read_unlock(&connections_srcu, idx); + + /* for debugging we print when we are done to compare with other + * messages in between. This function need to be correctly synchronized + * with io handling + */ + log_print("closing connection to node %d done", nodeid); + + return 0; +} + +/* Receive worker function */ +static void process_recv_sockets(struct work_struct *work) +{ + struct connection *con = container_of(work, struct connection, rwork); + int ret, buflen; + + down_read(&con->sock_lock); + if (!con->sock) { + up_read(&con->sock_lock); + return; + } + + buflen = READ_ONCE(dlm_config.ci_buffer_size); + do { + ret = receive_from_sock(con, buflen); + } while (ret == DLM_IO_SUCCESS); + up_read(&con->sock_lock); + + switch (ret) { + case DLM_IO_END: + /* CF_RECV_PENDING cleared */ + break; + case DLM_IO_EOF: + close_connection(con, false); + wake_up(&con->shutdown_wait); + /* CF_RECV_PENDING cleared */ + break; + case DLM_IO_RESCHED: + cond_resched(); + queue_work(io_workqueue, &con->rwork); + /* CF_RECV_PENDING not cleared */ + break; + default: + if (ret < 0) { + if (test_bit(CF_IS_OTHERCON, &con->flags)) { + close_connection(con, false); + } else { + spin_lock_bh(&con->writequeue_lock); + lowcomms_queue_swork(con); + spin_unlock_bh(&con->writequeue_lock); + } + + /* CF_RECV_PENDING cleared for othercon + * we trigger send queue if not already done + * and process_send_sockets will handle it + */ + break; + } + + WARN_ON_ONCE(1); + break; + } +} + +static void process_listen_recv_socket(struct work_struct *work) +{ + int ret; + + if (WARN_ON_ONCE(!listen_con.sock)) + return; + + do { + ret = accept_from_sock(); + } while (ret == DLM_IO_SUCCESS); + + if (ret < 0) + log_print("critical error accepting connection: %d", ret); +} + +static int dlm_connect(struct connection *con) +{ + struct sockaddr_storage addr; + int result, addr_len; + struct socket *sock; + unsigned int mark; + + memset(&addr, 0, sizeof(addr)); + result = nodeid_to_addr(con->nodeid, &addr, NULL, + dlm_proto_ops->try_new_addr, &mark); + if (result < 0) { + log_print("no address for nodeid %d", con->nodeid); + return result; + } + + /* Create a socket to communicate with */ + result = sock_create_kern(&init_net, dlm_local_addr[0].ss_family, + SOCK_STREAM, dlm_proto_ops->proto, &sock); + if (result < 0) + return result; + + sock_set_mark(sock->sk, mark); + dlm_proto_ops->sockopts(sock); + + result = dlm_proto_ops->bind(sock); + if (result < 0) { + sock_release(sock); + return result; + } + + add_sock(sock, con); + + log_print_ratelimited("connecting to %d", con->nodeid); + make_sockaddr(&addr, dlm_config.ci_tcp_port, &addr_len); + result = dlm_proto_ops->connect(con, sock, (struct sockaddr *)&addr, + addr_len); + switch (result) { + case -EINPROGRESS: + /* not an error */ + fallthrough; + case 0: + break; + default: + if (result < 0) + dlm_close_sock(&con->sock); + + break; + } + + return result; +} + +/* Send worker function */ +static void process_send_sockets(struct work_struct *work) +{ + struct connection *con = container_of(work, struct connection, swork); + int ret; + + WARN_ON_ONCE(test_bit(CF_IS_OTHERCON, &con->flags)); + + down_read(&con->sock_lock); + if (!con->sock) { + up_read(&con->sock_lock); + down_write(&con->sock_lock); + if (!con->sock) { + ret = dlm_connect(con); + switch (ret) { + case 0: + break; + case -EINPROGRESS: + /* avoid spamming resched on connection + * we might can switch to a state_change + * event based mechanism if established + */ + msleep(100); + break; + default: + /* CF_SEND_PENDING not cleared */ + up_write(&con->sock_lock); + log_print("connect to node %d try %d error %d", + con->nodeid, con->retries++, ret); + msleep(1000); + /* For now we try forever to reconnect. In + * future we should send a event to cluster + * manager to fence itself after certain amount + * of retries. + */ + queue_work(io_workqueue, &con->swork); + return; + } + } + downgrade_write(&con->sock_lock); + } + + do { + ret = send_to_sock(con); + } while (ret == DLM_IO_SUCCESS); + up_read(&con->sock_lock); + + switch (ret) { + case DLM_IO_END: + /* CF_SEND_PENDING cleared */ + break; + case DLM_IO_RESCHED: + /* CF_SEND_PENDING not cleared */ + cond_resched(); + queue_work(io_workqueue, &con->swork); + break; + default: + if (ret < 0) { + close_connection(con, false); + + /* CF_SEND_PENDING cleared */ + spin_lock_bh(&con->writequeue_lock); + lowcomms_queue_swork(con); + spin_unlock_bh(&con->writequeue_lock); + break; + } + + WARN_ON_ONCE(1); + break; + } +} + +static void work_stop(void) +{ + if (io_workqueue) { + destroy_workqueue(io_workqueue); + io_workqueue = NULL; + } + + if (process_workqueue) { + destroy_workqueue(process_workqueue); + process_workqueue = NULL; + } +} + +static int work_start(void) +{ + io_workqueue = alloc_workqueue("dlm_io", WQ_HIGHPRI | WQ_MEM_RECLAIM | + WQ_UNBOUND, 0); + if (!io_workqueue) { + log_print("can't start dlm_io"); + return -ENOMEM; + } + + /* ordered dlm message process queue, + * should be converted to a tasklet + */ + process_workqueue = alloc_ordered_workqueue("dlm_process", + WQ_HIGHPRI | WQ_MEM_RECLAIM); + if (!process_workqueue) { + log_print("can't start dlm_process"); + destroy_workqueue(io_workqueue); + io_workqueue = NULL; + return -ENOMEM; + } + + return 0; +} + +void dlm_lowcomms_shutdown(void) +{ + struct connection *con; + int i, idx; + + /* stop lowcomms_listen_data_ready calls */ + lock_sock(listen_con.sock->sk); + listen_con.sock->sk->sk_data_ready = listen_sock.sk_data_ready; + release_sock(listen_con.sock->sk); + + cancel_work_sync(&listen_con.rwork); + dlm_close_sock(&listen_con.sock); + + idx = srcu_read_lock(&connections_srcu); + for (i = 0; i < CONN_HASH_SIZE; i++) { + hlist_for_each_entry_rcu(con, &connection_hash[i], list) { + shutdown_connection(con, true); + stop_connection_io(con); + flush_workqueue(process_workqueue); + close_connection(con, true); + + clean_one_writequeue(con); + if (con->othercon) + clean_one_writequeue(con->othercon); + allow_connection_io(con); + } + } + srcu_read_unlock(&connections_srcu, idx); +} + +void dlm_lowcomms_stop(void) +{ + work_stop(); + dlm_proto_ops = NULL; +} + +static int dlm_listen_for_all(void) +{ + struct socket *sock; + int result; + + log_print("Using %s for communications", + dlm_proto_ops->name); + + result = dlm_proto_ops->listen_validate(); + if (result < 0) + return result; + + result = sock_create_kern(&init_net, dlm_local_addr[0].ss_family, + SOCK_STREAM, dlm_proto_ops->proto, &sock); + if (result < 0) { + log_print("Can't create comms socket: %d", result); + return result; + } + + sock_set_mark(sock->sk, dlm_config.ci_mark); + dlm_proto_ops->listen_sockopts(sock); + + result = dlm_proto_ops->listen_bind(sock); + if (result < 0) + goto out; + + lock_sock(sock->sk); + listen_sock.sk_data_ready = sock->sk->sk_data_ready; + listen_sock.sk_write_space = sock->sk->sk_write_space; + listen_sock.sk_error_report = sock->sk->sk_error_report; + listen_sock.sk_state_change = sock->sk->sk_state_change; + + listen_con.sock = sock; + + sock->sk->sk_allocation = GFP_NOFS; + sock->sk->sk_use_task_frag = false; + sock->sk->sk_data_ready = lowcomms_listen_data_ready; + release_sock(sock->sk); + + result = sock->ops->listen(sock, 128); + if (result < 0) { + dlm_close_sock(&listen_con.sock); + return result; + } + + return 0; + +out: + sock_release(sock); + return result; +} + +static int dlm_tcp_bind(struct socket *sock) +{ + struct sockaddr_storage src_addr; + int result, addr_len; + + /* Bind to our cluster-known address connecting to avoid + * routing problems. + */ + memcpy(&src_addr, &dlm_local_addr[0], sizeof(src_addr)); + make_sockaddr(&src_addr, 0, &addr_len); + + result = kernel_bind(sock, (struct sockaddr *)&src_addr, + addr_len); + if (result < 0) { + /* This *may* not indicate a critical error */ + log_print("could not bind for connect: %d", result); + } + + return 0; +} + +static int dlm_tcp_connect(struct connection *con, struct socket *sock, + struct sockaddr *addr, int addr_len) +{ + return kernel_connect(sock, addr, addr_len, O_NONBLOCK); +} + +static int dlm_tcp_listen_validate(void) +{ + /* We don't support multi-homed hosts */ + if (dlm_local_count > 1) { + log_print("TCP protocol can't handle multi-homed hosts, try SCTP"); + return -EINVAL; + } + + return 0; +} + +static void dlm_tcp_sockopts(struct socket *sock) +{ + /* Turn off Nagle's algorithm */ + tcp_sock_set_nodelay(sock->sk); +} + +static void dlm_tcp_listen_sockopts(struct socket *sock) +{ + dlm_tcp_sockopts(sock); + sock_set_reuseaddr(sock->sk); +} + +static int dlm_tcp_listen_bind(struct socket *sock) +{ + int addr_len; + + /* Bind to our port */ + make_sockaddr(&dlm_local_addr[0], dlm_config.ci_tcp_port, &addr_len); + return kernel_bind(sock, (struct sockaddr *)&dlm_local_addr[0], + addr_len); +} + +static const struct dlm_proto_ops dlm_tcp_ops = { + .name = "TCP", + .proto = IPPROTO_TCP, + .connect = dlm_tcp_connect, + .sockopts = dlm_tcp_sockopts, + .bind = dlm_tcp_bind, + .listen_validate = dlm_tcp_listen_validate, + .listen_sockopts = dlm_tcp_listen_sockopts, + .listen_bind = dlm_tcp_listen_bind, +}; + +static int dlm_sctp_bind(struct socket *sock) +{ + return sctp_bind_addrs(sock, 0); +} + +static int dlm_sctp_connect(struct connection *con, struct socket *sock, + struct sockaddr *addr, int addr_len) +{ + int ret; + + /* + * Make kernel_connect() function return in specified time, + * since O_NONBLOCK argument in connect() function does not work here, + * then, we should restore the default value of this attribute. + */ + sock_set_sndtimeo(sock->sk, 5); + ret = kernel_connect(sock, addr, addr_len, 0); + sock_set_sndtimeo(sock->sk, 0); + return ret; +} + +static int dlm_sctp_listen_validate(void) +{ + if (!IS_ENABLED(CONFIG_IP_SCTP)) { + log_print("SCTP is not enabled by this kernel"); + return -EOPNOTSUPP; + } + + request_module("sctp"); + return 0; +} + +static int dlm_sctp_bind_listen(struct socket *sock) +{ + return sctp_bind_addrs(sock, dlm_config.ci_tcp_port); +} + +static void dlm_sctp_sockopts(struct socket *sock) +{ + /* Turn off Nagle's algorithm */ + sctp_sock_set_nodelay(sock->sk); + sock_set_rcvbuf(sock->sk, NEEDED_RMEM); +} + +static const struct dlm_proto_ops dlm_sctp_ops = { + .name = "SCTP", + .proto = IPPROTO_SCTP, + .try_new_addr = true, + .connect = dlm_sctp_connect, + .sockopts = dlm_sctp_sockopts, + .bind = dlm_sctp_bind, + .listen_validate = dlm_sctp_listen_validate, + .listen_sockopts = dlm_sctp_sockopts, + .listen_bind = dlm_sctp_bind_listen, +}; + +int dlm_lowcomms_start(void) +{ + int error; + + init_local(); + if (!dlm_local_count) { + error = -ENOTCONN; + log_print("no local IP address has been set"); + goto fail; + } + + error = work_start(); + if (error) + goto fail; + + /* Start listening */ + switch (dlm_config.ci_protocol) { + case DLM_PROTO_TCP: + dlm_proto_ops = &dlm_tcp_ops; + break; + case DLM_PROTO_SCTP: + dlm_proto_ops = &dlm_sctp_ops; + break; + default: + log_print("Invalid protocol identifier %d set", + dlm_config.ci_protocol); + error = -EINVAL; + goto fail_proto_ops; + } + + error = dlm_listen_for_all(); + if (error) + goto fail_listen; + + return 0; + +fail_listen: + dlm_proto_ops = NULL; +fail_proto_ops: + work_stop(); +fail: + return error; +} + +void dlm_lowcomms_init(void) +{ + int i; + + for (i = 0; i < CONN_HASH_SIZE; i++) + INIT_HLIST_HEAD(&connection_hash[i]); + + INIT_WORK(&listen_con.rwork, process_listen_recv_socket); +} + +void dlm_lowcomms_exit(void) +{ + struct connection *con; + int i, idx; + + idx = srcu_read_lock(&connections_srcu); + for (i = 0; i < CONN_HASH_SIZE; i++) { + hlist_for_each_entry_rcu(con, &connection_hash[i], list) { + spin_lock(&connections_lock); + hlist_del_rcu(&con->list); + spin_unlock(&connections_lock); + + if (con->othercon) + call_srcu(&connections_srcu, &con->othercon->rcu, + connection_release); + call_srcu(&connections_srcu, &con->rcu, connection_release); + } + } + srcu_read_unlock(&connections_srcu, idx); +} |