// 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 #include #include #include #include #include #include #include #include #include #include "dlm_internal.h" #include "lowcomms.h" #include "midcomms.h" #include "config.h" #define NEEDED_RMEM (4*1024*1024) #define CONN_HASH_SIZE 32 /* Number of messages to send before rescheduling */ #define MAX_SEND_MSG_COUNT 25 #define DLM_SHUTDOWN_WAIT_TIMEOUT msecs_to_jiffies(10000) struct connection { struct socket *sock; /* NULL if not connected */ uint32_t nodeid; /* So we know who we are in the list */ struct mutex sock_mutex; unsigned long flags; #define CF_READ_PENDING 1 #define CF_WRITE_PENDING 2 #define CF_INIT_PENDING 4 #define CF_IS_OTHERCON 5 #define CF_CLOSE 6 #define CF_APP_LIMITED 7 #define CF_CLOSING 8 #define CF_SHUTDOWN 9 struct list_head writequeue; /* List of outgoing writequeue_entries */ spinlock_t writequeue_lock; int (*rx_action) (struct connection *); /* What to do when active */ void (*connect_action) (struct connection *); /* What to do to connect */ void (*shutdown_action)(struct connection *con); /* What to do to shutdown */ int retries; #define MAX_CONNECT_RETRIES 3 struct hlist_node list; struct connection *othercon; struct work_struct rwork; /* Receive workqueue */ struct work_struct swork; /* Send workqueue */ wait_queue_head_t shutdown_wait; /* wait for graceful shutdown */ unsigned char *rx_buf; int rx_buflen; int rx_leftover; struct rcu_head rcu; }; #define sock2con(x) ((struct connection *)(x)->sk_user_data) /* An entry waiting to be sent */ struct writequeue_entry { struct list_head list; struct page *page; int offset; int len; int end; int users; struct connection *con; }; struct dlm_node_addr { struct list_head list; int nodeid; int addr_count; int curr_addr_index; struct sockaddr_storage *addr[DLM_MAX_ADDR_COUNT]; }; 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 LIST_HEAD(dlm_node_addrs); static DEFINE_SPINLOCK(dlm_node_addrs_spin); static struct sockaddr_storage *dlm_local_addr[DLM_MAX_ADDR_COUNT]; static int dlm_local_count; static int dlm_allow_conn; /* Work queues */ static struct workqueue_struct *recv_workqueue; static struct workqueue_struct *send_workqueue; static struct hlist_head connection_hash[CONN_HASH_SIZE]; static DEFINE_SPINLOCK(connections_lock); DEFINE_STATIC_SRCU(connections_srcu); static void process_recv_sockets(struct work_struct *work); static void process_send_sockets(struct work_struct *work); /* This is deliberately very simple because most clusters have simple sequential nodeids, so we should be able to go straight to a connection struct in the array */ static inline int nodeid_hash(int nodeid) { return nodeid & (CONN_HASH_SIZE-1); } static struct connection *__find_con(int nodeid) { int r, idx; struct connection *con; r = nodeid_hash(nodeid); idx = srcu_read_lock(&connections_srcu); hlist_for_each_entry_rcu(con, &connection_hash[r], list) { if (con->nodeid == nodeid) { srcu_read_unlock(&connections_srcu, idx); return con; } } srcu_read_unlock(&connections_srcu, idx); return NULL; } /* * 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; con = __find_con(nodeid); if (con || !alloc) return con; con = kzalloc(sizeof(*con), alloc); if (!con) return NULL; con->rx_buflen = dlm_config.ci_buffer_size; con->rx_buf = kmalloc(con->rx_buflen, GFP_NOFS); if (!con->rx_buf) { kfree(con); return NULL; } con->nodeid = nodeid; mutex_init(&con->sock_mutex); 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); init_waitqueue_head(&con->shutdown_wait); /* Setup action pointers for child sockets */ if (con->nodeid) { struct connection *zerocon = __find_con(0); con->connect_action = zerocon->connect_action; if (!con->rx_action) con->rx_action = zerocon->rx_action; } r = nodeid_hash(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); if (tmp) { spin_unlock(&connections_lock); kfree(con->rx_buf); kfree(con); return tmp; } hlist_add_head_rcu(&con->list, &connection_hash[r]); spin_unlock(&connections_lock); return con; } /* Loop round all connections */ static void foreach_conn(void (*conn_func)(struct connection *c)) { int i, idx; struct connection *con; idx = srcu_read_lock(&connections_srcu); for (i = 0; i < CONN_HASH_SIZE; i++) { hlist_for_each_entry_rcu(con, &connection_hash[i], list) conn_func(con); } srcu_read_unlock(&connections_srcu, idx); } static struct dlm_node_addr *find_node_addr(int nodeid) { struct dlm_node_addr *na; list_for_each_entry(na, &dlm_node_addrs, list) { if (na->nodeid == nodeid) return na; } return NULL; } static int addr_compare(struct sockaddr_storage *x, 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) { struct sockaddr_storage sas; struct dlm_node_addr *na; if (!dlm_local_count) return -1; spin_lock(&dlm_node_addrs_spin); na = find_node_addr(nodeid); if (na && na->addr_count) { memcpy(&sas, na->addr[na->curr_addr_index], sizeof(struct sockaddr_storage)); if (try_new_addr) { na->curr_addr_index++; if (na->curr_addr_index == na->addr_count) na->curr_addr_index = 0; } } spin_unlock(&dlm_node_addrs_spin); if (!na) return -EEXIST; if (!na->addr_count) return -ENOENT; if (sas_out) memcpy(sas_out, &sas, sizeof(struct sockaddr_storage)); if (!sa_out) 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; } return 0; } static int addr_to_nodeid(struct sockaddr_storage *addr, int *nodeid) { struct dlm_node_addr *na; int rv = -EEXIST; int addr_i; spin_lock(&dlm_node_addrs_spin); list_for_each_entry(na, &dlm_node_addrs, list) { if (!na->addr_count) continue; for (addr_i = 0; addr_i < na->addr_count; addr_i++) { if (addr_compare(na->addr[addr_i], addr)) { *nodeid = na->nodeid; rv = 0; goto unlock; } } } unlock: spin_unlock(&dlm_node_addrs_spin); return rv; } int dlm_lowcomms_addr(int nodeid, struct sockaddr_storage *addr, int len) { struct sockaddr_storage *new_addr; struct dlm_node_addr *new_node, *na; new_node = kzalloc(sizeof(struct dlm_node_addr), GFP_NOFS); if (!new_node) return -ENOMEM; new_addr = kzalloc(sizeof(struct sockaddr_storage), GFP_NOFS); if (!new_addr) { kfree(new_node); return -ENOMEM; } memcpy(new_addr, addr, len); spin_lock(&dlm_node_addrs_spin); na = find_node_addr(nodeid); if (!na) { new_node->nodeid = nodeid; new_node->addr[0] = new_addr; new_node->addr_count = 1; list_add(&new_node->list, &dlm_node_addrs); spin_unlock(&dlm_node_addrs_spin); return 0; } if (na->addr_count >= DLM_MAX_ADDR_COUNT) { spin_unlock(&dlm_node_addrs_spin); kfree(new_addr); kfree(new_node); return -ENOSPC; } na->addr[na->addr_count++] = new_addr; spin_unlock(&dlm_node_addrs_spin); kfree(new_node); return 0; } /* Data available on socket or listen socket received a connect */ static void lowcomms_data_ready(struct sock *sk) { struct connection *con; read_lock_bh(&sk->sk_callback_lock); con = sock2con(sk); if (con && !test_and_set_bit(CF_READ_PENDING, &con->flags)) queue_work(recv_workqueue, &con->rwork); read_unlock_bh(&sk->sk_callback_lock); } static void lowcomms_write_space(struct sock *sk) { struct connection *con; read_lock_bh(&sk->sk_callback_lock); con = sock2con(sk); if (!con) goto out; clear_bit(SOCK_NOSPACE, &con->sock->flags); if (test_and_clear_bit(CF_APP_LIMITED, &con->flags)) { con->sock->sk->sk_write_pending--; clear_bit(SOCKWQ_ASYNC_NOSPACE, &con->sock->flags); } queue_work(send_workqueue, &con->swork); out: read_unlock_bh(&sk->sk_callback_lock); } static inline void lowcomms_connect_sock(struct connection *con) { if (test_bit(CF_CLOSE, &con->flags)) return; queue_work(send_workqueue, &con->swork); cond_resched(); } 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. Also, it * doesn't switch socket state when entering shutdown, so we * skip the write in that case. */ if (sk->sk_shutdown) { if (sk->sk_shutdown == RCV_SHUTDOWN) lowcomms_data_ready(sk); } else if (sk->sk_state == TCP_ESTABLISHED) { lowcomms_write_space(sk); } } int dlm_lowcomms_connect_node(int nodeid) { struct connection *con; if (nodeid == dlm_our_nodeid()) return 0; con = nodeid2con(nodeid, GFP_NOFS); if (!con) return -ENOMEM; lowcomms_connect_sock(con); return 0; } static void lowcomms_error_report(struct sock *sk) { struct connection *con; struct sockaddr_storage saddr; void (*orig_report)(struct sock *) = NULL; read_lock_bh(&sk->sk_callback_lock); con = sock2con(sk); if (con == NULL) goto out; orig_report = listen_sock.sk_error_report; if (con->sock == NULL || kernel_getpeername(con->sock, (struct sockaddr *)&saddr) < 0) { printk_ratelimited(KERN_ERR "dlm: node %d: socket error " "sending to node %d, port %d, " "sk_err=%d/%d\n", dlm_our_nodeid(), con->nodeid, dlm_config.ci_tcp_port, sk->sk_err, sk->sk_err_soft); } else if (saddr.ss_family == AF_INET) { struct sockaddr_in *sin4 = (struct sockaddr_in *)&saddr; printk_ratelimited(KERN_ERR "dlm: node %d: socket error " "sending to node %d at %pI4, port %d, " "sk_err=%d/%d\n", dlm_our_nodeid(), con->nodeid, &sin4->sin_addr.s_addr, dlm_config.ci_tcp_port, sk->sk_err, sk->sk_err_soft); } else { struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&saddr; printk_ratelimited(KERN_ERR "dlm: node %d: socket error " "sending to node %d at %u.%u.%u.%u, " "port %d, sk_err=%d/%d\n", dlm_our_nodeid(), con->nodeid, sin6->sin6_addr.s6_addr32[0], sin6->sin6_addr.s6_addr32[1], sin6->sin6_addr.s6_addr32[2], sin6->sin6_addr.s6_addr32[3], dlm_config.ci_tcp_port, sk->sk_err, sk->sk_err_soft); } out: read_unlock_bh(&sk->sk_callback_lock); if (orig_report) orig_report(sk); } /* Note: sk_callback_lock must be locked before calling this function. */ static void save_listen_callbacks(struct socket *sock) { struct sock *sk = sock->sk; listen_sock.sk_data_ready = sk->sk_data_ready; listen_sock.sk_state_change = sk->sk_state_change; listen_sock.sk_write_space = sk->sk_write_space; listen_sock.sk_error_report = sk->sk_error_report; } static void restore_callbacks(struct socket *sock) { struct sock *sk = sock->sk; write_lock_bh(&sk->sk_callback_lock); 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; write_unlock_bh(&sk->sk_callback_lock); } /* Make a socket active */ static void add_sock(struct socket *sock, struct connection *con) { struct sock *sk = sock->sk; write_lock_bh(&sk->sk_callback_lock); con->sock = sock; sk->sk_user_data = con; /* Install a data_ready callback */ sk->sk_data_ready = lowcomms_data_ready; sk->sk_write_space = lowcomms_write_space; sk->sk_state_change = lowcomms_state_change; sk->sk_allocation = GFP_NOFS; sk->sk_error_report = lowcomms_error_report; write_unlock_bh(&sk->sk_callback_lock); } /* 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); } /* Close a remote connection and tidy up */ static void close_connection(struct connection *con, bool and_other, bool tx, bool rx) { bool closing = test_and_set_bit(CF_CLOSING, &con->flags); if (tx && !closing && cancel_work_sync(&con->swork)) { log_print("canceled swork for node %d", con->nodeid); clear_bit(CF_WRITE_PENDING, &con->flags); } if (rx && !closing && cancel_work_sync(&con->rwork)) { log_print("canceled rwork for node %d", con->nodeid); clear_bit(CF_READ_PENDING, &con->flags); } mutex_lock(&con->sock_mutex); if (con->sock) { restore_callbacks(con->sock); sock_release(con->sock); con->sock = NULL; } if (con->othercon && and_other) { /* Will only re-enter once. */ close_connection(con->othercon, false, tx, rx); } con->rx_leftover = 0; con->retries = 0; mutex_unlock(&con->sock_mutex); clear_bit(CF_CLOSING, &con->flags); } static void shutdown_connection(struct connection *con) { int ret; flush_work(&con->swork); mutex_lock(&con->sock_mutex); /* nothing to shutdown */ if (!con->sock) { mutex_unlock(&con->sock_mutex); return; } set_bit(CF_SHUTDOWN, &con->flags); ret = kernel_sock_shutdown(con->sock, SHUT_WR); mutex_unlock(&con->sock_mutex); 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, !test_bit(CF_SHUTDOWN, &con->flags), DLM_SHUTDOWN_WAIT_TIMEOUT); if (ret == 0) { log_print("Connection %p shutdown timed out, will force close", con); goto force_close; } } return; force_close: clear_bit(CF_SHUTDOWN, &con->flags); close_connection(con, false, true, true); } static void dlm_tcp_shutdown(struct connection *con) { if (con->othercon) shutdown_connection(con->othercon); shutdown_connection(con); } static int con_realloc_receive_buf(struct connection *con, int newlen) { unsigned char *newbuf; newbuf = kmalloc(newlen, GFP_NOFS); if (!newbuf) return -ENOMEM; /* copy any leftover from last receive */ if (con->rx_leftover) memmove(newbuf, con->rx_buf, con->rx_leftover); /* swap to new buffer space */ kfree(con->rx_buf); con->rx_buflen = newlen; con->rx_buf = newbuf; return 0; } /* Data received from remote end */ static int receive_from_sock(struct connection *con) { int call_again_soon = 0; struct msghdr msg; struct kvec iov; int ret, buflen; mutex_lock(&con->sock_mutex); if (con->sock == NULL) { ret = -EAGAIN; goto out_close; } if (con->nodeid == 0) { ret = -EINVAL; goto out_close; } /* realloc if we get new buffer size to read out */ buflen = dlm_config.ci_buffer_size; if (con->rx_buflen != buflen && con->rx_leftover <= buflen) { ret = con_realloc_receive_buf(con, buflen); if (ret < 0) goto out_resched; } /* calculate new buffer parameter regarding last receive and * possible leftover bytes */ iov.iov_base = con->rx_buf + con->rx_leftover; iov.iov_len = con->rx_buflen - con->rx_leftover; memset(&msg, 0, sizeof(msg)); msg.msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL; ret = kernel_recvmsg(con->sock, &msg, &iov, 1, iov.iov_len, msg.msg_flags); if (ret <= 0) goto out_close; else if (ret == iov.iov_len) call_again_soon = 1; /* new buflen according readed bytes and leftover from last receive */ buflen = ret + con->rx_leftover; ret = dlm_process_incoming_buffer(con->nodeid, con->rx_buf, buflen); if (ret < 0) goto out_close; /* 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 - ret; if (con->rx_leftover) { memmove(con->rx_buf, con->rx_buf + ret, con->rx_leftover); call_again_soon = true; } if (call_again_soon) goto out_resched; mutex_unlock(&con->sock_mutex); return 0; out_resched: if (!test_and_set_bit(CF_READ_PENDING, &con->flags)) queue_work(recv_workqueue, &con->rwork); mutex_unlock(&con->sock_mutex); return -EAGAIN; out_close: mutex_unlock(&con->sock_mutex); if (ret != -EAGAIN) { /* Reconnect when there is something to send */ close_connection(con, false, true, false); if (ret == 0) { log_print("connection %p got EOF from %d", con, con->nodeid); /* handling for tcp shutdown */ clear_bit(CF_SHUTDOWN, &con->flags); wake_up(&con->shutdown_wait); /* signal to breaking receive worker */ ret = -1; } } return ret; } /* Listening socket is busy, accept a connection */ static int accept_from_sock(struct connection *con) { int result; struct sockaddr_storage peeraddr; struct socket *newsock; int len; int nodeid; struct connection *newcon; struct connection *addcon; unsigned int mark; if (!dlm_allow_conn) { return -1; } mutex_lock_nested(&con->sock_mutex, 0); if (!con->sock) { mutex_unlock(&con->sock_mutex); return -ENOTCONN; } result = kernel_accept(con->sock, &newsock, O_NONBLOCK); 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)) { unsigned char *b=(unsigned char *)&peeraddr; log_print("connect from non cluster node"); print_hex_dump_bytes("ss: ", DUMP_PREFIX_NONE, b, sizeof(struct sockaddr_storage)); sock_release(newsock); mutex_unlock(&con->sock_mutex); return -1; } dlm_comm_mark(nodeid, &mark); sock_set_mark(newsock->sk, mark); 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" */ newcon = nodeid2con(nodeid, GFP_NOFS); if (!newcon) { result = -ENOMEM; goto accept_err; } mutex_lock_nested(&newcon->sock_mutex, 1); 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"); mutex_unlock(&newcon->sock_mutex); result = -ENOMEM; goto accept_err; } othercon->rx_buflen = dlm_config.ci_buffer_size; othercon->rx_buf = kmalloc(othercon->rx_buflen, GFP_NOFS); if (!othercon->rx_buf) { mutex_unlock(&newcon->sock_mutex); kfree(othercon); log_print("failed to allocate incoming socket receive buffer"); result = -ENOMEM; goto accept_err; } othercon->nodeid = nodeid; othercon->rx_action = receive_from_sock; mutex_init(&othercon->sock_mutex); INIT_LIST_HEAD(&othercon->writequeue); spin_lock_init(&othercon->writequeue_lock); INIT_WORK(&othercon->swork, process_send_sockets); INIT_WORK(&othercon->rwork, process_recv_sockets); init_waitqueue_head(&othercon->shutdown_wait); set_bit(CF_IS_OTHERCON, &othercon->flags); } else { /* close other sock con if we have something new */ close_connection(othercon, false, true, false); } mutex_lock_nested(&othercon->sock_mutex, 2); newcon->othercon = othercon; add_sock(newsock, othercon); addcon = othercon; mutex_unlock(&othercon->sock_mutex); } else { newcon->rx_action = receive_from_sock; /* 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); addcon = newcon; } mutex_unlock(&newcon->sock_mutex); /* * Add it to the active queue in case we got data * between processing the accept adding the socket * to the read_sockets list */ if (!test_and_set_bit(CF_READ_PENDING, &addcon->flags)) queue_work(recv_workqueue, &addcon->rwork); mutex_unlock(&con->sock_mutex); return 0; accept_err: mutex_unlock(&con->sock_mutex); if (newsock) sock_release(newsock); if (result != -EAGAIN) log_print("error accepting connection from node: %d", result); return result; } static void free_entry(struct writequeue_entry *e) { __free_page(e->page); kfree(e); } /* * 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; if (e->len == 0 && e->users == 0) { list_del(&e->list); free_entry(e); } } /* * sctp_bind_addrs - bind a SCTP socket to all our addresses */ static int sctp_bind_addrs(struct connection *con, 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(con->sock, addr, addr_len); else result = sock_bind_add(con->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; } /* Initiate an SCTP association. This is a special case of send_to_sock() in that we don't yet have a peeled-off socket for this association, so we use the listening socket and add the primary IP address of the remote node. */ static void sctp_connect_to_sock(struct connection *con) { struct sockaddr_storage daddr; int result; int addr_len; struct socket *sock; unsigned int mark; if (con->nodeid == 0) { log_print("attempt to connect sock 0 foiled"); return; } dlm_comm_mark(con->nodeid, &mark); mutex_lock(&con->sock_mutex); /* Some odd races can cause double-connects, ignore them */ if (con->retries++ > MAX_CONNECT_RETRIES) goto out; if (con->sock) { log_print("node %d already connected.", con->nodeid); goto out; } memset(&daddr, 0, sizeof(daddr)); result = nodeid_to_addr(con->nodeid, &daddr, NULL, true); if (result < 0) { log_print("no address for nodeid %d", con->nodeid); goto out; } /* Create a socket to communicate with */ result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family, SOCK_STREAM, IPPROTO_SCTP, &sock); if (result < 0) goto socket_err; sock_set_mark(sock->sk, mark); con->rx_action = receive_from_sock; con->connect_action = sctp_connect_to_sock; add_sock(sock, con); /* Bind to all addresses. */ if (sctp_bind_addrs(con, 0)) goto bind_err; make_sockaddr(&daddr, dlm_config.ci_tcp_port, &addr_len); log_print("connecting to %d", con->nodeid); /* Turn off Nagle's algorithm */ sctp_sock_set_nodelay(sock->sk); /* * Make sock->ops->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); result = sock->ops->connect(sock, (struct sockaddr *)&daddr, addr_len, 0); sock_set_sndtimeo(sock->sk, 0); if (result == -EINPROGRESS) result = 0; if (result == 0) goto out; bind_err: con->sock = NULL; sock_release(sock); socket_err: /* * Some errors are fatal and this list might need adjusting. For other * errors we try again until the max number of retries is reached. */ if (result != -EHOSTUNREACH && result != -ENETUNREACH && result != -ENETDOWN && result != -EINVAL && result != -EPROTONOSUPPORT) { log_print("connect %d try %d error %d", con->nodeid, con->retries, result); mutex_unlock(&con->sock_mutex); msleep(1000); lowcomms_connect_sock(con); return; } out: mutex_unlock(&con->sock_mutex); } /* Connect a new socket to its peer */ static void tcp_connect_to_sock(struct connection *con) { struct sockaddr_storage saddr, src_addr; int addr_len; struct socket *sock = NULL; unsigned int mark; int result; if (con->nodeid == 0) { log_print("attempt to connect sock 0 foiled"); return; } dlm_comm_mark(con->nodeid, &mark); mutex_lock(&con->sock_mutex); if (con->retries++ > MAX_CONNECT_RETRIES) goto out; /* Some odd races can cause double-connects, ignore them */ if (con->sock) goto out; /* Create a socket to communicate with */ result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family, SOCK_STREAM, IPPROTO_TCP, &sock); if (result < 0) goto out_err; sock_set_mark(sock->sk, mark); memset(&saddr, 0, sizeof(saddr)); result = nodeid_to_addr(con->nodeid, &saddr, NULL, false); if (result < 0) { log_print("no address for nodeid %d", con->nodeid); goto out_err; } con->rx_action = receive_from_sock; con->connect_action = tcp_connect_to_sock; con->shutdown_action = dlm_tcp_shutdown; add_sock(sock, con); /* 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 = sock->ops->bind(sock, (struct sockaddr *) &src_addr, addr_len); if (result < 0) { log_print("could not bind for connect: %d", result); /* This *may* not indicate a critical error */ } make_sockaddr(&saddr, dlm_config.ci_tcp_port, &addr_len); log_print("connecting to %d", con->nodeid); /* Turn off Nagle's algorithm */ tcp_sock_set_nodelay(sock->sk); result = sock->ops->connect(sock, (struct sockaddr *)&saddr, addr_len, O_NONBLOCK); if (result == -EINPROGRESS) result = 0; if (result == 0) goto out; out_err: if (con->sock) { sock_release(con->sock); con->sock = NULL; } else if (sock) { sock_release(sock); } /* * Some errors are fatal and this list might need adjusting. For other * errors we try again until the max number of retries is reached. */ if (result != -EHOSTUNREACH && result != -ENETUNREACH && result != -ENETDOWN && result != -EINVAL && result != -EPROTONOSUPPORT) { log_print("connect %d try %d error %d", con->nodeid, con->retries, result); mutex_unlock(&con->sock_mutex); msleep(1000); lowcomms_connect_sock(con); return; } out: mutex_unlock(&con->sock_mutex); return; } static struct socket *tcp_create_listen_sock(struct connection *con, struct sockaddr_storage *saddr) { struct socket *sock = NULL; int result = 0; int addr_len; if (dlm_local_addr[0]->ss_family == AF_INET) addr_len = sizeof(struct sockaddr_in); else addr_len = sizeof(struct sockaddr_in6); /* Create a socket to communicate with */ result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family, SOCK_STREAM, IPPROTO_TCP, &sock); if (result < 0) { log_print("Can't create listening comms socket"); goto create_out; } sock_set_mark(sock->sk, dlm_config.ci_mark); /* Turn off Nagle's algorithm */ tcp_sock_set_nodelay(sock->sk); sock_set_reuseaddr(sock->sk); write_lock_bh(&sock->sk->sk_callback_lock); sock->sk->sk_user_data = con; save_listen_callbacks(sock); con->rx_action = accept_from_sock; con->connect_action = tcp_connect_to_sock; write_unlock_bh(&sock->sk->sk_callback_lock); /* Bind to our port */ make_sockaddr(saddr, dlm_config.ci_tcp_port, &addr_len); result = sock->ops->bind(sock, (struct sockaddr *) saddr, addr_len); if (result < 0) { log_print("Can't bind to port %d", dlm_config.ci_tcp_port); sock_release(sock); sock = NULL; con->sock = NULL; goto create_out; } sock_set_keepalive(sock->sk); result = sock->ops->listen(sock, 5); if (result < 0) { log_print("Can't listen on port %d", dlm_config.ci_tcp_port); sock_release(sock); sock = NULL; goto create_out; } create_out: return sock; } /* Get local addresses */ static void init_local(void) { struct sockaddr_storage sas, *addr; int i; dlm_local_count = 0; for (i = 0; i < DLM_MAX_ADDR_COUNT; i++) { if (dlm_our_addr(&sas, i)) break; addr = kmemdup(&sas, sizeof(*addr), GFP_NOFS); if (!addr) break; dlm_local_addr[dlm_local_count++] = addr; } } static void deinit_local(void) { int i; for (i = 0; i < dlm_local_count; i++) kfree(dlm_local_addr[i]); } /* Initialise SCTP socket and bind to all interfaces */ static int sctp_listen_for_all(void) { struct socket *sock = NULL; int result = -EINVAL; struct connection *con = nodeid2con(0, GFP_NOFS); if (!con) return -ENOMEM; log_print("Using SCTP for communications"); result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family, SOCK_STREAM, IPPROTO_SCTP, &sock); if (result < 0) { log_print("Can't create comms socket, check SCTP is loaded"); goto out; } sock_set_rcvbuf(sock->sk, NEEDED_RMEM); sock_set_mark(sock->sk, dlm_config.ci_mark); sctp_sock_set_nodelay(sock->sk); write_lock_bh(&sock->sk->sk_callback_lock); /* Init con struct */ sock->sk->sk_user_data = con; save_listen_callbacks(sock); con->sock = sock; con->sock->sk->sk_data_ready = lowcomms_data_ready; con->rx_action = accept_from_sock; con->connect_action = sctp_connect_to_sock; write_unlock_bh(&sock->sk->sk_callback_lock); /* Bind to all addresses. */ if (sctp_bind_addrs(con, dlm_config.ci_tcp_port)) goto create_delsock; result = sock->ops->listen(sock, 5); if (result < 0) { log_print("Can't set socket listening"); goto create_delsock; } return 0; create_delsock: sock_release(sock); con->sock = NULL; out: return result; } static int tcp_listen_for_all(void) { struct socket *sock = NULL; struct connection *con = nodeid2con(0, GFP_NOFS); int result = -EINVAL; if (!con) return -ENOMEM; /* We don't support multi-homed hosts */ if (dlm_local_addr[1] != NULL) { log_print("TCP protocol can't handle multi-homed hosts, " "try SCTP"); return -EINVAL; } log_print("Using TCP for communications"); sock = tcp_create_listen_sock(con, dlm_local_addr[0]); if (sock) { add_sock(sock, con); result = 0; } else { result = -EADDRINUSE; } return result; } static struct writequeue_entry *new_writequeue_entry(struct connection *con, gfp_t allocation) { struct writequeue_entry *entry; entry = kmalloc(sizeof(struct writequeue_entry), allocation); if (!entry) return NULL; entry->page = alloc_page(allocation); if (!entry->page) { kfree(entry); return NULL; } entry->offset = 0; entry->len = 0; entry->end = 0; entry->users = 0; entry->con = con; return entry; } void *dlm_lowcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc) { struct connection *con; struct writequeue_entry *e; int offset = 0; con = nodeid2con(nodeid, allocation); if (!con) return NULL; spin_lock(&con->writequeue_lock); e = list_entry(con->writequeue.prev, struct writequeue_entry, list); if ((&e->list == &con->writequeue) || (PAGE_SIZE - e->end < len)) { e = NULL; } else { offset = e->end; e->end += len; e->users++; } spin_unlock(&con->writequeue_lock); if (e) { got_one: *ppc = page_address(e->page) + offset; return e; } e = new_writequeue_entry(con, allocation); if (e) { spin_lock(&con->writequeue_lock); offset = e->end; e->end += len; e->users++; list_add_tail(&e->list, &con->writequeue); spin_unlock(&con->writequeue_lock); goto got_one; } return NULL; } void dlm_lowcomms_commit_buffer(void *mh) { struct writequeue_entry *e = (struct writequeue_entry *)mh; struct connection *con = e->con; int users; spin_lock(&con->writequeue_lock); users = --e->users; if (users) goto out; e->len = e->end - e->offset; spin_unlock(&con->writequeue_lock); queue_work(send_workqueue, &con->swork); return; out: spin_unlock(&con->writequeue_lock); return; } /* Send a message */ static void send_to_sock(struct connection *con) { int ret = 0; const int msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL; struct writequeue_entry *e; int len, offset; int count = 0; mutex_lock(&con->sock_mutex); if (con->sock == NULL) goto out_connect; spin_lock(&con->writequeue_lock); for (;;) { e = list_entry(con->writequeue.next, struct writequeue_entry, list); if ((struct list_head *) e == &con->writequeue) break; len = e->len; offset = e->offset; BUG_ON(len == 0 && e->users == 0); spin_unlock(&con->writequeue_lock); ret = 0; if (len) { ret = kernel_sendpage(con->sock, e->page, offset, len, msg_flags); if (ret == -EAGAIN || ret == 0) { if (ret == -EAGAIN && 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->flags); con->sock->sk->sk_write_pending++; } cond_resched(); goto out; } else if (ret < 0) goto send_error; } /* Don't starve people filling buffers */ if (++count >= MAX_SEND_MSG_COUNT) { cond_resched(); count = 0; } spin_lock(&con->writequeue_lock); writequeue_entry_complete(e, ret); } spin_unlock(&con->writequeue_lock); out: mutex_unlock(&con->sock_mutex); return; send_error: mutex_unlock(&con->sock_mutex); close_connection(con, false, false, true); /* Requeue the send work. When the work daemon runs again, it will try a new connection, then call this function again. */ queue_work(send_workqueue, &con->swork); return; out_connect: mutex_unlock(&con->sock_mutex); queue_work(send_workqueue, &con->swork); cond_resched(); } static void clean_one_writequeue(struct connection *con) { struct writequeue_entry *e, *safe; spin_lock(&con->writequeue_lock); list_for_each_entry_safe(e, safe, &con->writequeue, list) { list_del(&e->list); free_entry(e); } spin_unlock(&con->writequeue_lock); } /* Called from recovery when it knows that a node has left the cluster */ int dlm_lowcomms_close(int nodeid) { struct connection *con; struct dlm_node_addr *na; log_print("closing connection to node %d", nodeid); con = nodeid2con(nodeid, 0); if (con) { set_bit(CF_CLOSE, &con->flags); close_connection(con, true, true, true); clean_one_writequeue(con); } spin_lock(&dlm_node_addrs_spin); na = find_node_addr(nodeid); if (na) { list_del(&na->list); while (na->addr_count--) kfree(na->addr[na->addr_count]); kfree(na); } spin_unlock(&dlm_node_addrs_spin); return 0; } /* Receive workqueue function */ static void process_recv_sockets(struct work_struct *work) { struct connection *con = container_of(work, struct connection, rwork); int err; clear_bit(CF_READ_PENDING, &con->flags); do { err = con->rx_action(con); } while (!err); } /* Send workqueue function */ static void process_send_sockets(struct work_struct *work) { struct connection *con = container_of(work, struct connection, swork); clear_bit(CF_WRITE_PENDING, &con->flags); if (con->sock == NULL) /* not mutex protected so check it inside too */ con->connect_action(con); if (!list_empty(&con->writequeue)) send_to_sock(con); } static void work_stop(void) { if (recv_workqueue) destroy_workqueue(recv_workqueue); if (send_workqueue) destroy_workqueue(send_workqueue); } static int work_start(void) { recv_workqueue = alloc_workqueue("dlm_recv", WQ_UNBOUND | WQ_MEM_RECLAIM, 1); if (!recv_workqueue) { log_print("can't start dlm_recv"); return -ENOMEM; } send_workqueue = alloc_workqueue("dlm_send", WQ_UNBOUND | WQ_MEM_RECLAIM, 1); if (!send_workqueue) { log_print("can't start dlm_send"); destroy_workqueue(recv_workqueue); return -ENOMEM; } return 0; } static void _stop_conn(struct connection *con, bool and_other) { mutex_lock(&con->sock_mutex); set_bit(CF_CLOSE, &con->flags); set_bit(CF_READ_PENDING, &con->flags); set_bit(CF_WRITE_PENDING, &con->flags); if (con->sock && con->sock->sk) { write_lock_bh(&con->sock->sk->sk_callback_lock); con->sock->sk->sk_user_data = NULL; write_unlock_bh(&con->sock->sk->sk_callback_lock); } if (con->othercon && and_other) _stop_conn(con->othercon, false); mutex_unlock(&con->sock_mutex); } static void stop_conn(struct connection *con) { _stop_conn(con, true); } static void shutdown_conn(struct connection *con) { if (con->shutdown_action) con->shutdown_action(con); } static void connection_release(struct rcu_head *rcu) { struct connection *con = container_of(rcu, struct connection, rcu); kfree(con->rx_buf); kfree(con); } static void free_conn(struct connection *con) { close_connection(con, true, true, true); spin_lock(&connections_lock); hlist_del_rcu(&con->list); spin_unlock(&connections_lock); if (con->othercon) { clean_one_writequeue(con->othercon); call_rcu(&con->othercon->rcu, connection_release); } clean_one_writequeue(con); call_rcu(&con->rcu, connection_release); } static void work_flush(void) { int ok, idx; int i; struct connection *con; do { ok = 1; foreach_conn(stop_conn); if (recv_workqueue) flush_workqueue(recv_workqueue); if (send_workqueue) flush_workqueue(send_workqueue); idx = srcu_read_lock(&connections_srcu); for (i = 0; i < CONN_HASH_SIZE && ok; i++) { hlist_for_each_entry_rcu(con, &connection_hash[i], list) { ok &= test_bit(CF_READ_PENDING, &con->flags); ok &= test_bit(CF_WRITE_PENDING, &con->flags); if (con->othercon) { ok &= test_bit(CF_READ_PENDING, &con->othercon->flags); ok &= test_bit(CF_WRITE_PENDING, &con->othercon->flags); } } } srcu_read_unlock(&connections_srcu, idx); } while (!ok); } void dlm_lowcomms_stop(void) { /* Set all the flags to prevent any socket activity. */ dlm_allow_conn = 0; if (recv_workqueue) flush_workqueue(recv_workqueue); if (send_workqueue) flush_workqueue(send_workqueue); foreach_conn(shutdown_conn); work_flush(); foreach_conn(free_conn); work_stop(); deinit_local(); } int dlm_lowcomms_start(void) { int error = -EINVAL; struct connection *con; int i; for (i = 0; i < CONN_HASH_SIZE; i++) INIT_HLIST_HEAD(&connection_hash[i]); 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; dlm_allow_conn = 1; /* Start listening */ if (dlm_config.ci_protocol == 0) error = tcp_listen_for_all(); else error = sctp_listen_for_all(); if (error) goto fail_unlisten; return 0; fail_unlisten: dlm_allow_conn = 0; con = nodeid2con(0,0); if (con) free_conn(con); fail: return error; } void dlm_lowcomms_exit(void) { struct dlm_node_addr *na, *safe; spin_lock(&dlm_node_addrs_spin); list_for_each_entry_safe(na, safe, &dlm_node_addrs, list) { list_del(&na->list); while (na->addr_count--) kfree(na->addr[na->addr_count]); kfree(na); } spin_unlock(&dlm_node_addrs_spin); }