/****************************************************************************** ******************************************************************************* ** ** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved. ** Copyright (C) 2004-2009 Red Hat, Inc. All rights reserved. ** ** This copyrighted material is made available to anyone wishing to use, ** modify, copy, or redistribute it subject to the terms and conditions ** of the GNU General Public License v.2. ** ******************************************************************************* ******************************************************************************/ /* * 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 struct cbuf { unsigned int base; unsigned int len; unsigned int mask; }; static void cbuf_add(struct cbuf *cb, int n) { cb->len += n; } static int cbuf_data(struct cbuf *cb) { return ((cb->base + cb->len) & cb->mask); } static void cbuf_init(struct cbuf *cb, int size) { cb->base = cb->len = 0; cb->mask = size-1; } static void cbuf_eat(struct cbuf *cb, int n) { cb->len -= n; cb->base += n; cb->base &= cb->mask; } static bool cbuf_empty(struct cbuf *cb) { return cb->len == 0; } 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_CONNECT_PENDING 3 #define CF_INIT_PENDING 4 #define CF_IS_OTHERCON 5 #define CF_CLOSE 6 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 */ struct page *rx_page; struct cbuf cb; int retries; #define MAX_CONNECT_RETRIES 3 int sctp_assoc; struct hlist_node list; struct connection *othercon; struct work_struct rwork; /* Receive workqueue */ struct work_struct swork; /* Send workqueue */ }; #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; }; static struct sockaddr_storage *dlm_local_addr[DLM_MAX_ADDR_COUNT]; static int dlm_local_count; /* 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_MUTEX(connections_lock); static struct kmem_cache *con_cache; 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; struct hlist_node *h; struct connection *con; r = nodeid_hash(nodeid); hlist_for_each_entry(con, h, &connection_hash[r], list) { if (con->nodeid == nodeid) return con; } 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 = NULL; int r; con = __find_con(nodeid); if (con || !alloc) return con; con = kmem_cache_zalloc(con_cache, alloc); if (!con) return NULL; r = nodeid_hash(nodeid); hlist_add_head(&con->list, &connection_hash[r]); 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); /* 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; } return con; } /* Loop round all connections */ static void foreach_conn(void (*conn_func)(struct connection *c)) { int i; struct hlist_node *h, *n; struct connection *con; for (i = 0; i < CONN_HASH_SIZE; i++) { hlist_for_each_entry_safe(con, h, n, &connection_hash[i], list){ conn_func(con); } } } static struct connection *nodeid2con(int nodeid, gfp_t allocation) { struct connection *con; mutex_lock(&connections_lock); con = __nodeid2con(nodeid, allocation); mutex_unlock(&connections_lock); return con; } /* This is a bit drastic, but only called when things go wrong */ static struct connection *assoc2con(int assoc_id) { int i; struct hlist_node *h; struct connection *con; mutex_lock(&connections_lock); for (i = 0 ; i < CONN_HASH_SIZE; i++) { hlist_for_each_entry(con, h, &connection_hash[i], list) { if (con->sctp_assoc == assoc_id) { mutex_unlock(&connections_lock); return con; } } } mutex_unlock(&connections_lock); return NULL; } static int nodeid_to_addr(int nodeid, struct sockaddr *retaddr) { struct sockaddr_storage addr; int error; if (!dlm_local_count) return -1; error = dlm_nodeid_to_addr(nodeid, &addr); if (error) return error; if (dlm_local_addr[0]->ss_family == AF_INET) { struct sockaddr_in *in4 = (struct sockaddr_in *) &addr; struct sockaddr_in *ret4 = (struct sockaddr_in *) retaddr; ret4->sin_addr.s_addr = in4->sin_addr.s_addr; } else { struct sockaddr_in6 *in6 = (struct sockaddr_in6 *) &addr; struct sockaddr_in6 *ret6 = (struct sockaddr_in6 *) retaddr; ipv6_addr_copy(&ret6->sin6_addr, &in6->sin6_addr); } return 0; } /* Data available on socket or listen socket received a connect */ static void lowcomms_data_ready(struct sock *sk, int count_unused) { struct connection *con = sock2con(sk); if (con && !test_and_set_bit(CF_READ_PENDING, &con->flags)) queue_work(recv_workqueue, &con->rwork); } static void lowcomms_write_space(struct sock *sk) { struct connection *con = sock2con(sk); if (con && !test_and_set_bit(CF_WRITE_PENDING, &con->flags)) queue_work(send_workqueue, &con->swork); } static inline void lowcomms_connect_sock(struct connection *con) { if (test_bit(CF_CLOSE, &con->flags)) return; if (!test_and_set_bit(CF_CONNECT_PENDING, &con->flags)) queue_work(send_workqueue, &con->swork); } static void lowcomms_state_change(struct sock *sk) { if (sk->sk_state == TCP_ESTABLISHED) lowcomms_write_space(sk); } int dlm_lowcomms_connect_node(int nodeid) { struct connection *con; /* with sctp there's no connecting without sending */ if (dlm_config.ci_protocol != 0) return 0; if (nodeid == dlm_our_nodeid()) return 0; con = nodeid2con(nodeid, GFP_NOFS); if (!con) return -ENOMEM; lowcomms_connect_sock(con); return 0; } /* Make a socket active */ static int add_sock(struct socket *sock, struct connection *con) { con->sock = sock; /* Install a data_ready callback */ con->sock->sk->sk_data_ready = lowcomms_data_ready; con->sock->sk->sk_write_space = lowcomms_write_space; con->sock->sk->sk_state_change = lowcomms_state_change; con->sock->sk->sk_user_data = con; con->sock->sk->sk_allocation = GFP_NOFS; return 0; } /* 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) { mutex_lock(&con->sock_mutex); if (con->sock) { sock_release(con->sock); con->sock = NULL; } if (con->othercon && and_other) { /* Will only re-enter once. */ close_connection(con->othercon, false); } if (con->rx_page) { __free_page(con->rx_page); con->rx_page = NULL; } con->retries = 0; mutex_unlock(&con->sock_mutex); } /* We only send shutdown messages to nodes that are not part of the cluster */ static void sctp_send_shutdown(sctp_assoc_t associd) { static char outcmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))]; struct msghdr outmessage; struct cmsghdr *cmsg; struct sctp_sndrcvinfo *sinfo; int ret; struct connection *con; con = nodeid2con(0,0); BUG_ON(con == NULL); outmessage.msg_name = NULL; outmessage.msg_namelen = 0; outmessage.msg_control = outcmsg; outmessage.msg_controllen = sizeof(outcmsg); outmessage.msg_flags = MSG_EOR; cmsg = CMSG_FIRSTHDR(&outmessage); cmsg->cmsg_level = IPPROTO_SCTP; cmsg->cmsg_type = SCTP_SNDRCV; cmsg->cmsg_len = CMSG_LEN(sizeof(struct sctp_sndrcvinfo)); outmessage.msg_controllen = cmsg->cmsg_len; sinfo = CMSG_DATA(cmsg); memset(sinfo, 0x00, sizeof(struct sctp_sndrcvinfo)); sinfo->sinfo_flags |= MSG_EOF; sinfo->sinfo_assoc_id = associd; ret = kernel_sendmsg(con->sock, &outmessage, NULL, 0, 0); if (ret != 0) log_print("send EOF to node failed: %d", ret); } static void sctp_init_failed_foreach(struct connection *con) { con->sctp_assoc = 0; if (test_and_clear_bit(CF_CONNECT_PENDING, &con->flags)) { if (!test_and_set_bit(CF_WRITE_PENDING, &con->flags)) queue_work(send_workqueue, &con->swork); } } /* INIT failed but we don't know which node... restart INIT on all pending nodes */ static void sctp_init_failed(void) { mutex_lock(&connections_lock); foreach_conn(sctp_init_failed_foreach); mutex_unlock(&connections_lock); } /* Something happened to an association */ static void process_sctp_notification(struct connection *con, struct msghdr *msg, char *buf) { union sctp_notification *sn = (union sctp_notification *)buf; if (sn->sn_header.sn_type == SCTP_ASSOC_CHANGE) { switch (sn->sn_assoc_change.sac_state) { case SCTP_COMM_UP: case SCTP_RESTART: { /* Check that the new node is in the lockspace */ struct sctp_prim prim; int nodeid; int prim_len, ret; int addr_len; struct connection *new_con; sctp_peeloff_arg_t parg; int parglen = sizeof(parg); int err; /* * We get this before any data for an association. * We verify that the node is in the cluster and * then peel off a socket for it. */ if ((int)sn->sn_assoc_change.sac_assoc_id <= 0) { log_print("COMM_UP for invalid assoc ID %d", (int)sn->sn_assoc_change.sac_assoc_id); sctp_init_failed(); return; } memset(&prim, 0, sizeof(struct sctp_prim)); prim_len = sizeof(struct sctp_prim); prim.ssp_assoc_id = sn->sn_assoc_change.sac_assoc_id; ret = kernel_getsockopt(con->sock, IPPROTO_SCTP, SCTP_PRIMARY_ADDR, (char*)&prim, &prim_len); if (ret < 0) { log_print("getsockopt/sctp_primary_addr on " "new assoc %d failed : %d", (int)sn->sn_assoc_change.sac_assoc_id, ret); /* Retry INIT later */ new_con = assoc2con(sn->sn_assoc_change.sac_assoc_id); if (new_con) clear_bit(CF_CONNECT_PENDING, &con->flags); return; } make_sockaddr(&prim.ssp_addr, 0, &addr_len); if (dlm_addr_to_nodeid(&prim.ssp_addr, &nodeid)) { int i; unsigned char *b=(unsigned char *)&prim.ssp_addr; log_print("reject connect from unknown addr"); for (i=0; isn_assoc_change.sac_assoc_id; ret = kernel_getsockopt(con->sock, IPPROTO_SCTP, SCTP_SOCKOPT_PEELOFF, (void *)&parg, &parglen); if (ret < 0) { log_print("Can't peel off a socket for " "connection %d to node %d: err=%d", parg.associd, nodeid, ret); return; } new_con->sock = sockfd_lookup(parg.sd, &err); if (!new_con->sock) { log_print("sockfd_lookup error %d", err); return; } add_sock(new_con->sock, new_con); sockfd_put(new_con->sock); log_print("connecting to %d sctp association %d", nodeid, (int)sn->sn_assoc_change.sac_assoc_id); /* Send any pending writes */ clear_bit(CF_CONNECT_PENDING, &new_con->flags); clear_bit(CF_INIT_PENDING, &con->flags); if (!test_and_set_bit(CF_WRITE_PENDING, &new_con->flags)) { queue_work(send_workqueue, &new_con->swork); } if (!test_and_set_bit(CF_READ_PENDING, &new_con->flags)) queue_work(recv_workqueue, &new_con->rwork); } break; case SCTP_COMM_LOST: case SCTP_SHUTDOWN_COMP: { con = assoc2con(sn->sn_assoc_change.sac_assoc_id); if (con) { con->sctp_assoc = 0; } } break; /* We don't know which INIT failed, so clear the PENDING flags * on them all. if assoc_id is zero then it will then try * again */ case SCTP_CANT_STR_ASSOC: { log_print("Can't start SCTP association - retrying"); sctp_init_failed(); } break; default: log_print("unexpected SCTP assoc change id=%d state=%d", (int)sn->sn_assoc_change.sac_assoc_id, sn->sn_assoc_change.sac_state); } } } /* Data received from remote end */ static int receive_from_sock(struct connection *con) { int ret = 0; struct msghdr msg = {}; struct kvec iov[2]; unsigned len; int r; int call_again_soon = 0; int nvec; char incmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))]; mutex_lock(&con->sock_mutex); if (con->sock == NULL) { ret = -EAGAIN; goto out_close; } if (con->rx_page == NULL) { /* * This doesn't need to be atomic, but I think it should * improve performance if it is. */ con->rx_page = alloc_page(GFP_ATOMIC); if (con->rx_page == NULL) goto out_resched; cbuf_init(&con->cb, PAGE_CACHE_SIZE); } /* Only SCTP needs these really */ memset(&incmsg, 0, sizeof(incmsg)); msg.msg_control = incmsg; msg.msg_controllen = sizeof(incmsg); /* * iov[0] is the bit of the circular buffer between the current end * point (cb.base + cb.len) and the end of the buffer. */ iov[0].iov_len = con->cb.base - cbuf_data(&con->cb); iov[0].iov_base = page_address(con->rx_page) + cbuf_data(&con->cb); iov[1].iov_len = 0; nvec = 1; /* * iov[1] is the bit of the circular buffer between the start of the * buffer and the start of the currently used section (cb.base) */ if (cbuf_data(&con->cb) >= con->cb.base) { iov[0].iov_len = PAGE_CACHE_SIZE - cbuf_data(&con->cb); iov[1].iov_len = con->cb.base; iov[1].iov_base = page_address(con->rx_page); nvec = 2; } len = iov[0].iov_len + iov[1].iov_len; r = ret = kernel_recvmsg(con->sock, &msg, iov, nvec, len, MSG_DONTWAIT | MSG_NOSIGNAL); if (ret <= 0) goto out_close; /* Process SCTP notifications */ if (msg.msg_flags & MSG_NOTIFICATION) { msg.msg_control = incmsg; msg.msg_controllen = sizeof(incmsg); process_sctp_notification(con, &msg, page_address(con->rx_page) + con->cb.base); mutex_unlock(&con->sock_mutex); return 0; } BUG_ON(con->nodeid == 0); if (ret == len) call_again_soon = 1; cbuf_add(&con->cb, ret); ret = dlm_process_incoming_buffer(con->nodeid, page_address(con->rx_page), con->cb.base, con->cb.len, PAGE_CACHE_SIZE); if (ret == -EBADMSG) { log_print("lowcomms: addr=%p, base=%u, len=%u, " "iov_len=%u, iov_base[0]=%p, read=%d", page_address(con->rx_page), con->cb.base, con->cb.len, len, iov[0].iov_base, r); } if (ret < 0) goto out_close; cbuf_eat(&con->cb, ret); if (cbuf_empty(&con->cb) && !call_again_soon) { __free_page(con->rx_page); con->rx_page = NULL; } 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) { close_connection(con, false); /* Reconnect when there is something to send */ } /* Don't return success if we really got EOF */ if (ret == 0) ret = -EAGAIN; return ret; } /* Listening socket is busy, accept a connection */ static int tcp_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; memset(&peeraddr, 0, sizeof(peeraddr)); result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_STREAM, IPPROTO_TCP, &newsock); if (result < 0) return -ENOMEM; mutex_lock_nested(&con->sock_mutex, 0); result = -ENOTCONN; if (con->sock == NULL) goto accept_err; newsock->type = con->sock->type; newsock->ops = con->sock->ops; result = con->sock->ops->accept(con->sock, newsock, O_NONBLOCK); if (result < 0) goto accept_err; /* Get the connected socket's peer */ memset(&peeraddr, 0, sizeof(peeraddr)); if (newsock->ops->getname(newsock, (struct sockaddr *)&peeraddr, &len, 2)) { result = -ECONNABORTED; goto accept_err; } /* Get the new node's NODEID */ make_sockaddr(&peeraddr, 0, &len); if (dlm_addr_to_nodeid(&peeraddr, &nodeid)) { log_print("connect from non cluster node"); sock_release(newsock); mutex_unlock(&con->sock_mutex); 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" */ 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 = kmem_cache_zalloc(con_cache, GFP_NOFS); if (!othercon) { log_print("failed to allocate incoming socket"); mutex_unlock(&newcon->sock_mutex); result = -ENOMEM; goto accept_err; } othercon->nodeid = nodeid; othercon->rx_action = receive_from_sock; mutex_init(&othercon->sock_mutex); INIT_WORK(&othercon->swork, process_send_sockets); INIT_WORK(&othercon->rwork, process_recv_sockets); set_bit(CF_IS_OTHERCON, &othercon->flags); } if (!othercon->sock) { newcon->othercon = othercon; othercon->sock = newsock; newsock->sk->sk_user_data = othercon; add_sock(newsock, othercon); addcon = othercon; } else { printk("Extra connection from node %d attempted\n", nodeid); result = -EAGAIN; mutex_unlock(&newcon->sock_mutex); goto accept_err; } } else { newsock->sk->sk_user_data = newcon; newcon->rx_action = receive_from_sock; add_sock(newsock, newcon); addcon = newcon; } mutex_unlock(&newcon->sock_mutex); /* * Add it to the active queue in case we got data * beween 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); 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); } /* 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_init_assoc(struct connection *con) { struct sockaddr_storage rem_addr; char outcmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))]; struct msghdr outmessage; struct cmsghdr *cmsg; struct sctp_sndrcvinfo *sinfo; struct connection *base_con; struct writequeue_entry *e; int len, offset; int ret; int addrlen; struct kvec iov[1]; if (test_and_set_bit(CF_INIT_PENDING, &con->flags)) return; if (con->retries++ > MAX_CONNECT_RETRIES) return; if (nodeid_to_addr(con->nodeid, (struct sockaddr *)&rem_addr)) { log_print("no address for nodeid %d", con->nodeid); return; } base_con = nodeid2con(0, 0); BUG_ON(base_con == NULL); make_sockaddr(&rem_addr, dlm_config.ci_tcp_port, &addrlen); outmessage.msg_name = &rem_addr; outmessage.msg_namelen = addrlen; outmessage.msg_control = outcmsg; outmessage.msg_controllen = sizeof(outcmsg); outmessage.msg_flags = MSG_EOR; spin_lock(&con->writequeue_lock); if (list_empty(&con->writequeue)) { spin_unlock(&con->writequeue_lock); log_print("writequeue empty for nodeid %d", con->nodeid); return; } e = list_first_entry(&con->writequeue, struct writequeue_entry, list); len = e->len; offset = e->offset; spin_unlock(&con->writequeue_lock); /* Send the first block off the write queue */ iov[0].iov_base = page_address(e->page)+offset; iov[0].iov_len = len; cmsg = CMSG_FIRSTHDR(&outmessage); cmsg->cmsg_level = IPPROTO_SCTP; cmsg->cmsg_type = SCTP_SNDRCV; cmsg->cmsg_len = CMSG_LEN(sizeof(struct sctp_sndrcvinfo)); sinfo = CMSG_DATA(cmsg); memset(sinfo, 0x00, sizeof(struct sctp_sndrcvinfo)); sinfo->sinfo_ppid = cpu_to_le32(dlm_our_nodeid()); outmessage.msg_controllen = cmsg->cmsg_len; ret = kernel_sendmsg(base_con->sock, &outmessage, iov, 1, len); if (ret < 0) { log_print("Send first packet to node %d failed: %d", con->nodeid, ret); /* Try again later */ clear_bit(CF_CONNECT_PENDING, &con->flags); clear_bit(CF_INIT_PENDING, &con->flags); } else { spin_lock(&con->writequeue_lock); e->offset += ret; e->len -= ret; if (e->len == 0 && e->users == 0) { list_del(&e->list); free_entry(e); } spin_unlock(&con->writequeue_lock); } } /* Connect a new socket to its peer */ static void tcp_connect_to_sock(struct connection *con) { int result = -EHOSTUNREACH; struct sockaddr_storage saddr, src_addr; int addr_len; struct socket *sock = NULL; if (con->nodeid == 0) { log_print("attempt to connect sock 0 foiled"); return; } 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) { result = 0; goto out; } /* Create a socket to communicate with */ result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_STREAM, IPPROTO_TCP, &sock); if (result < 0) goto out_err; memset(&saddr, 0, sizeof(saddr)); if (dlm_nodeid_to_addr(con->nodeid, &saddr)) goto out_err; sock->sk->sk_user_data = con; con->rx_action = receive_from_sock; con->connect_action = tcp_connect_to_sock; 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); 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) { lowcomms_connect_sock(con); result = 0; } 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 one = 1; 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(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; } result = kernel_setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (char *)&one, sizeof(one)); if (result < 0) { log_print("Failed to set SO_REUSEADDR on socket: %d", result); } sock->sk->sk_user_data = con; con->rx_action = tcp_accept_from_sock; con->connect_action = tcp_connect_to_sock; con->sock = sock; /* 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; } result = kernel_setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (char *)&one, sizeof(one)); if (result < 0) { log_print("Set keepalive failed: %d", result); } 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 - 1; i++) { if (dlm_our_addr(&sas, i)) break; addr = kmalloc(sizeof(*addr), GFP_NOFS); if (!addr) break; memcpy(addr, &sas, sizeof(*addr)); dlm_local_addr[dlm_local_count++] = addr; } } /* Bind to an IP address. SCTP allows multiple address so it can do multi-homing */ static int add_sctp_bind_addr(struct connection *sctp_con, struct sockaddr_storage *addr, int addr_len, int num) { int result = 0; if (num == 1) result = kernel_bind(sctp_con->sock, (struct sockaddr *) addr, addr_len); else result = kernel_setsockopt(sctp_con->sock, SOL_SCTP, SCTP_SOCKOPT_BINDX_ADD, (char *)addr, addr_len); if (result < 0) log_print("Can't bind to port %d addr number %d", dlm_config.ci_tcp_port, num); return result; } /* Initialise SCTP socket and bind to all interfaces */ static int sctp_listen_for_all(void) { struct socket *sock = NULL; struct sockaddr_storage localaddr; struct sctp_event_subscribe subscribe; int result = -EINVAL, num = 1, i, addr_len; struct connection *con = nodeid2con(0, GFP_NOFS); int bufsize = NEEDED_RMEM; if (!con) return -ENOMEM; log_print("Using SCTP for communications"); result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_SEQPACKET, IPPROTO_SCTP, &sock); if (result < 0) { log_print("Can't create comms socket, check SCTP is loaded"); goto out; } /* Listen for events */ memset(&subscribe, 0, sizeof(subscribe)); subscribe.sctp_data_io_event = 1; subscribe.sctp_association_event = 1; subscribe.sctp_send_failure_event = 1; subscribe.sctp_shutdown_event = 1; subscribe.sctp_partial_delivery_event = 1; result = kernel_setsockopt(sock, SOL_SOCKET, SO_RCVBUFFORCE, (char *)&bufsize, sizeof(bufsize)); if (result) log_print("Error increasing buffer space on socket %d", result); result = kernel_setsockopt(sock, SOL_SCTP, SCTP_EVENTS, (char *)&subscribe, sizeof(subscribe)); if (result < 0) { log_print("Failed to set SCTP_EVENTS on socket: result=%d", result); goto create_delsock; } /* Init con struct */ sock->sk->sk_user_data = con; con->sock = sock; con->sock->sk->sk_data_ready = lowcomms_data_ready; con->rx_action = receive_from_sock; con->connect_action = sctp_init_assoc; /* Bind to all interfaces. */ for (i = 0; i < dlm_local_count; i++) { memcpy(&localaddr, dlm_local_addr[i], sizeof(localaddr)); make_sockaddr(&localaddr, dlm_config.ci_tcp_port, &addr_len); result = add_sctp_bind_addr(con, &localaddr, addr_len, num); if (result) goto create_delsock; ++num; } 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; int users = 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_CACHE_SIZE - e->end < len)) { e = NULL; } else { offset = e->end; e->end += len; users = 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; users = 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); if (!test_and_set_bit(CF_WRITE_PENDING, &con->flags)) { 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; 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) { cond_resched(); goto out; } if (ret <= 0) goto send_error; } /* Don't starve people filling buffers */ cond_resched(); spin_lock(&con->writequeue_lock); e->offset += ret; e->len -= ret; if (e->len == 0 && e->users == 0) { list_del(&e->list); free_entry(e); continue; } } spin_unlock(&con->writequeue_lock); out: mutex_unlock(&con->sock_mutex); return; send_error: mutex_unlock(&con->sock_mutex); close_connection(con, false); lowcomms_connect_sock(con); return; out_connect: mutex_unlock(&con->sock_mutex); if (!test_bit(CF_INIT_PENDING, &con->flags)) lowcomms_connect_sock(con); return; } 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; log_print("closing connection to node %d", nodeid); con = nodeid2con(nodeid, 0); if (con) { clear_bit(CF_CONNECT_PENDING, &con->flags); clear_bit(CF_WRITE_PENDING, &con->flags); set_bit(CF_CLOSE, &con->flags); if (cancel_work_sync(&con->swork)) log_print("canceled swork for node %d", nodeid); if (cancel_work_sync(&con->rwork)) log_print("canceled rwork for node %d", nodeid); clean_one_writequeue(con); close_connection(con, true); } 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); if (test_and_clear_bit(CF_CONNECT_PENDING, &con->flags)) { con->connect_action(con); set_bit(CF_WRITE_PENDING, &con->flags); } if (test_and_clear_bit(CF_WRITE_PENDING, &con->flags)) send_to_sock(con); } /* Discard all entries on the write queues */ static void clean_writequeues(void) { foreach_conn(clean_one_writequeue); } static void work_stop(void) { destroy_workqueue(recv_workqueue); destroy_workqueue(send_workqueue); } static int work_start(void) { int error; recv_workqueue = create_workqueue("dlm_recv"); error = IS_ERR(recv_workqueue); if (error) { log_print("can't start dlm_recv %d", error); return error; } send_workqueue = create_singlethread_workqueue("dlm_send"); error = IS_ERR(send_workqueue); if (error) { log_print("can't start dlm_send %d", error); destroy_workqueue(recv_workqueue); return error; } return 0; } static void stop_conn(struct connection *con) { con->flags |= 0x0F; if (con->sock && con->sock->sk) con->sock->sk->sk_user_data = NULL; } static void free_conn(struct connection *con) { close_connection(con, true); if (con->othercon) kmem_cache_free(con_cache, con->othercon); hlist_del(&con->list); kmem_cache_free(con_cache, con); } void dlm_lowcomms_stop(void) { /* Set all the flags to prevent any socket activity. */ mutex_lock(&connections_lock); foreach_conn(stop_conn); mutex_unlock(&connections_lock); work_stop(); mutex_lock(&connections_lock); clean_writequeues(); foreach_conn(free_conn); mutex_unlock(&connections_lock); kmem_cache_destroy(con_cache); } 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 out; } error = -ENOMEM; con_cache = kmem_cache_create("dlm_conn", sizeof(struct connection), __alignof__(struct connection), 0, NULL); if (!con_cache) goto out; /* Start listening */ if (dlm_config.ci_protocol == 0) error = tcp_listen_for_all(); else error = sctp_listen_for_all(); if (error) goto fail_unlisten; error = work_start(); if (error) goto fail_unlisten; return 0; fail_unlisten: con = nodeid2con(0,0); if (con) { close_connection(con, false); kmem_cache_free(con_cache, con); } kmem_cache_destroy(con_cache); out: return error; }