diff options
Diffstat (limited to 'src/kernel/net.c')
| -rw-r--r-- | src/kernel/net.c | 1929 |
1 files changed, 968 insertions, 961 deletions
diff --git a/src/kernel/net.c b/src/kernel/net.c index 9e48b86..5ef4016 100644 --- a/src/kernel/net.c +++ b/src/kernel/net.c @@ -1,9 +1,10 @@ +// SPDX-License-Identifier: GPL-2.0 /* * This file is part of the Distributed Network Block Device 3 * * Copyright(c) 2011-2012 Johann Latocha <johann@latocha.de> * - * This file may be licensed under the terms of of the + * This file may be licensed under the terms of the * GNU General Public License Version 2 (the ``GPL''). * * Software distributed under the License is distributed @@ -18,1106 +19,1112 @@ * */ -#include "clientconfig.h" +#include <dnbd3/config/client.h> #include "net.h" #include "blk.h" -#include "utils.h" +#include "dnbd3_main.h" -#include "serialize.h" +#include <dnbd3/shared/serialize.h> + +#include <linux/random.h> +#if LINUX_VERSION_CODE < KERNEL_VERSION(5, 15, 0) +#define get_random_u32 prandom_u32 +#endif #include <linux/time.h> -#include <linux/signal.h> +#include <linux/ktime.h> +#include <linux/tcp.h> #ifndef MIN -#define MIN(a,b) ((a) < (b) ? (a) : (b)) +#define MIN(a, b) ((a) < (b) ? (a) : (b)) #endif -#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 2, 0) -#define dnbd3_sock_create(af,type,proto,sock) sock_create_kern(&init_net, (af) == HOST_IP4 ? AF_INET : AF_INET6, type, proto, sock) -#else -#define dnbd3_sock_create(af,type,proto,sock) sock_create_kern((af) == HOST_IP4 ? AF_INET : AF_INET6, type, proto, sock) +#ifndef ktime_to_s +#define ktime_to_s(kt) ktime_divns(kt, NSEC_PER_SEC) #endif -#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 11, 0) -// cmd_flags and cmd_type are merged into cmd_flags now -#if REQ_FLAG_BITS > 24 -#error "Fix CMD bitshift" -#endif -// Pack into cmd_flags field by shifting CMD_* into unused bits of cmd_flags -#define dnbd3_cmd_to_priv(req, cmd) (req)->cmd_flags = REQ_OP_DRV_IN | ((cmd) << REQ_FLAG_BITS) -#define dnbd3_priv_to_cmd(req) ((req)->cmd_flags >> REQ_FLAG_BITS) -#define dnbd3_req_op(req) req_op(req) -#define DNBD3_DEV_READ REQ_OP_READ -#define DNBD3_REQ_OP_SPECIAL REQ_OP_DRV_IN +#ifdef DEBUG +#define ASSERT(x) \ + do { \ + if (!(x)) { \ + printk(KERN_EMERG "assertion failed %s: %d: %s\n", __FILE__, __LINE__, #x); \ + BUG(); \ + } \ + } while (0) #else -// Old way with type and flags separated -#define dnbd3_cmd_to_priv(req, cmd) do { \ - (req)->cmd_type = REQ_TYPE_SPECIAL; \ - (req)->cmd_flags = (cmd); \ -} while (0) -#define dnbd3_priv_to_cmd(req) (req)->cmd_flags -#define dnbd3_req_op(req) (req)->cmd_type -#define DNBD3_DEV_READ REQ_TYPE_FS -#define DNBD3_REQ_OP_SPECIAL REQ_TYPE_SPECIAL +#define ASSERT(x) \ + do { \ + } while (0) #endif -/** - * Some macros for easier debug output. Location in source-code - * as well as server IP:port info will be printed. - * The error_* macros include a "goto error;" at the end - */ -#if 1 // Change to 0 to disable debug messages -#define debug_print_va_host(_host, _fmt, ...) do { \ - if ((_host).type == HOST_IP4) \ - printk("%s:%d " _fmt " (%s, %pI4:%d)\n", __FILE__, __LINE__, __VA_ARGS__, dev->disk->disk_name, (_host).addr, (int)ntohs((_host).port)); \ - else \ - printk("%s:%d " _fmt " (%s, [%pI6]:%d)\n", __FILE__, __LINE__, __VA_ARGS__, dev->disk->disk_name, (_host).addr, (int)ntohs((_host).port)); \ -} while(0) -#define debug_error_va_host(_host, _fmt, ...) do { \ - debug_print_va_host(_host, _fmt, __VA_ARGS__); \ - goto error; \ -} while(0) -#define debug_dev_va(_fmt, ...) debug_print_va_host(dev->cur_server.host, _fmt, __VA_ARGS__) -#define error_dev_va(_fmt, ...) debug_error_va_host(dev->cur_server.host, _fmt, __VA_ARGS__) -#define debug_alt_va(_fmt, ...) debug_print_va_host(dev->alt_servers[i].host, _fmt, __VA_ARGS__) -#define error_alt_va(_fmt, ...) debug_error_va_host(dev->alt_servers[i].host, _fmt, __VA_ARGS__) - -#define debug_print_host(_host, txt) do { \ - if ((_host).type == HOST_IP4) \ - printk("%s:%d " txt " (%s, %pI4:%d)\n", __FILE__, __LINE__, dev->disk->disk_name, (_host).addr, (int)ntohs((_host).port)); \ - else \ - printk("%s:%d " txt " (%s, [%pI6]:%d)\n", __FILE__, __LINE__, dev->disk->disk_name, (_host).addr, (int)ntohs((_host).port)); \ -} while(0) -#define debug_error_host(_host, txt) do { \ - debug_print_host(_host, txt); \ - goto error; \ -} while(0) -#define debug_dev(txt) debug_print_host(dev->cur_server.host, txt) -#define error_dev(txt) debug_error_host(dev->cur_server.host, txt) -#define debug_alt(txt) debug_print_host(dev->alt_servers[i].host, txt) -#define error_alt(txt) debug_error_host(dev->alt_servers[i].host, txt) - -#else // Silent -#define debug_dev(x) do { } while(0) -#define error_dev(x) goto error -#define debug_dev_va(x, ...) do { } while(0) -#define error_dev_va(x, ...) goto error -#define debug_alt(x) do { } while(0) -#define error_alt(x) goto error -#define debug_alt_va(x, ...) do { } while(0) -#define error_alt_va(x, ...) goto error -#endif +#define dnbd3_dev_dbg_host(dev, host, fmt, ...) \ + dev_dbg(dnbd3_device_to_dev(dev), "(%pISpc): " fmt, (host), ##__VA_ARGS__) +#define dnbd3_dev_info_host(dev, host, fmt, ...) \ + dev_info(dnbd3_device_to_dev(dev), "(%pISpc): " fmt, (host), ##__VA_ARGS__) +#define dnbd3_dev_err_host(dev, host, fmt, ...) \ + dev_err(dnbd3_device_to_dev(dev), "(%pISpc): " fmt, (host), ##__VA_ARGS__) -static inline int is_same_server(const dnbd3_server_t * const a, const dnbd3_server_t * const b) -{ - return (a->host.type == b->host.type) && (a->host.port == b->host.port) - && (0 == memcmp(a->host.addr, b->host.addr, (a->host.type == HOST_IP4 ? 4 : 16))); -} +#define dnbd3_dev_dbg_cur(dev, fmt, ...) \ + dnbd3_dev_dbg_host(dev, &(dev)->cur_server.host, fmt, ##__VA_ARGS__) +#define dnbd3_dev_info_cur(dev, fmt, ...) \ + dnbd3_dev_info_host(dev, &(dev)->cur_server.host, fmt, ##__VA_ARGS__) +#define dnbd3_dev_err_cur(dev, fmt, ...) \ + dnbd3_dev_err_host(dev, &(dev)->cur_server.host, fmt, ##__VA_ARGS__) -static inline dnbd3_server_t *get_existing_server(const dnbd3_server_entry_t * const newserver, - dnbd3_device_t * const dev) -{ - int i; - for (i = 0; i < NUMBER_SERVERS; ++i) - { - if ((newserver->host.type == dev->alt_servers[i].host.type) - && (newserver->host.port == dev->alt_servers[i].host.port) - && (0 - == memcmp(newserver->host.addr, dev->alt_servers[i].host.addr, (newserver->host.type == HOST_IP4 ? 4 : 16)))) - { - return &dev->alt_servers[i]; - break; - } - } - return NULL ; -} - -static inline dnbd3_server_t *get_free_alt_server(dnbd3_device_t * const dev) -{ - int i; - for (i = 0; i < NUMBER_SERVERS; ++i) - { - if (dev->alt_servers[i].host.type == 0) - return &dev->alt_servers[i]; - } - for (i = 0; i < NUMBER_SERVERS; ++i) - { - if (dev->alt_servers[i].failures > 10) - return &dev->alt_servers[i]; - } - return NULL ; -} +static bool dnbd3_drain_socket(dnbd3_device_t *dev, struct socket *sock, int bytes); +static int dnbd3_recv_bytes(struct socket *sock, void *buffer, size_t count); +static int dnbd3_recv_reply(struct socket *sock, dnbd3_reply_t *reply_hdr); +static bool dnbd3_send_request(struct socket *sock, u16 cmd, u64 handle, u64 offset, u32 size); -int dnbd3_net_connect(dnbd3_device_t *dev) -{ - struct request *req1 = NULL; - struct timeval timeout; +static int dnbd3_set_primary_connection(dnbd3_device_t *dev, struct socket *sock, + struct sockaddr_storage *addr, u16 protocol_version); - if (dev->disconnecting) { - debug_dev("CONNECT: Still disconnecting!!!\n"); - while (dev->disconnecting) - schedule(); - } - if (dev->thread_receive != NULL) { - debug_dev("CONNECT: Still receiving!!!\n"); - while (dev->thread_receive != NULL) - schedule(); - } - if (dev->thread_send != NULL) { - debug_dev("CONNECT: Still sending!!!\n"); - while (dev->thread_send != NULL) - schedule(); - } +static int dnbd3_connect(dnbd3_device_t *dev, struct sockaddr_storage *addr, + struct socket **sock_out); - timeout.tv_sec = SOCKET_TIMEOUT_CLIENT_DATA; - timeout.tv_usec = 0; +static bool dnbd3_execute_handshake(dnbd3_device_t *dev, struct socket *sock, + struct sockaddr_storage *addr, uint16_t *remote_version, bool copy_image_info); - // do some checks before connecting +static bool dnbd3_request_test_block(dnbd3_device_t *dev, struct sockaddr_storage *addr, + struct socket *sock); - req1 = kmalloc(sizeof(*req1), GFP_ATOMIC ); - if (!req1) - error_dev("FATAL: Kmalloc(1) failed."); +static bool dnbd3_send_empty_request(dnbd3_device_t *dev, u16 cmd); - if (dev->cur_server.host.port == 0 || dev->cur_server.host.type == 0 || dev->imgname == NULL ) - error_dev("FATAL: Host, port or image name not set."); - if (dev->sock) - error_dev("ERROR: Already connected."); - - if (dev->cur_server.host.type != HOST_IP4 && dev->cur_server.host.type != HOST_IP6) - error_dev_va("ERROR: Unknown address type %d", (int)dev->cur_server.host.type); - - debug_dev("INFO: Connecting..."); - - if (dev->better_sock == NULL ) - { - // no established connection yet from discovery thread, start new one - dnbd3_request_t dnbd3_request; - dnbd3_reply_t dnbd3_reply; - struct msghdr msg; - struct kvec iov[2]; - uint16_t rid; - char *name; - int mlen; - init_msghdr(msg); - - if (dnbd3_sock_create(dev->cur_server.host.type, SOCK_STREAM, IPPROTO_TCP, &dev->sock) < 0) - error_dev("ERROR: Couldn't create socket (v6)."); - - kernel_setsockopt(dev->sock, SOL_SOCKET, SO_SNDTIMEO, (char *)&timeout, sizeof(timeout)); - kernel_setsockopt(dev->sock, SOL_SOCKET, SO_RCVTIMEO, (char *)&timeout, sizeof(timeout)); - dev->sock->sk->sk_allocation = GFP_NOIO; - if (dev->cur_server.host.type == HOST_IP4) - { - struct sockaddr_in sin; - memset(&sin, 0, sizeof(sin)); - sin.sin_family = AF_INET; - memcpy(&(sin.sin_addr), dev->cur_server.host.addr, 4); - sin.sin_port = dev->cur_server.host.port; - if (kernel_connect(dev->sock, (struct sockaddr *)&sin, sizeof(sin), 0) != 0) - error_dev("FATAL: Connection to host failed. (v4)"); - } - else - { - struct sockaddr_in6 sin; - memset(&sin, 0, sizeof(sin)); - sin.sin6_family = AF_INET6; - memcpy(&(sin.sin6_addr), dev->cur_server.host.addr, 16); - sin.sin6_port = dev->cur_server.host.port; - if (kernel_connect(dev->sock, (struct sockaddr *)&sin, sizeof(sin), 0) != 0) - error_dev("FATAL: Connection to host failed. (v6)"); - } - // Request filesize - dnbd3_request.magic = dnbd3_packet_magic; - dnbd3_request.cmd = CMD_SELECT_IMAGE; - iov[0].iov_base = &dnbd3_request; - iov[0].iov_len = sizeof(dnbd3_request); - serializer_reset_write(&dev->payload_buffer); - serializer_put_uint16(&dev->payload_buffer, PROTOCOL_VERSION); - serializer_put_string(&dev->payload_buffer, dev->imgname); - serializer_put_uint16(&dev->payload_buffer, dev->rid); - serializer_put_uint8(&dev->payload_buffer, 0); // is_server = false - iov[1].iov_base = &dev->payload_buffer; - dnbd3_request.size = iov[1].iov_len = serializer_get_written_length(&dev->payload_buffer); - fixup_request(dnbd3_request); - mlen = sizeof(dnbd3_request) + iov[1].iov_len; - if (kernel_sendmsg(dev->sock, &msg, iov, 2, mlen) != mlen) - error_dev("ERROR: Couldn't send CMD_SIZE_REQUEST."); - // receive reply header - iov[0].iov_base = &dnbd3_reply; - iov[0].iov_len = sizeof(dnbd3_reply); - if (kernel_recvmsg(dev->sock, &msg, iov, 1, sizeof(dnbd3_reply), msg.msg_flags) != sizeof(dnbd3_reply)) - error_dev("FATAL: Received corrupted reply header after CMD_SIZE_REQUEST."); - // check reply header - fixup_reply(dnbd3_reply); - if (dnbd3_reply.cmd != CMD_SELECT_IMAGE || dnbd3_reply.size < 3 || dnbd3_reply.size > MAX_PAYLOAD - || dnbd3_reply.magic != dnbd3_packet_magic) - error_dev("FATAL: Received invalid reply to CMD_SIZE_REQUEST, image doesn't exist on server."); - // receive reply payload - iov[0].iov_base = &dev->payload_buffer; - iov[0].iov_len = dnbd3_reply.size; - if (kernel_recvmsg(dev->sock, &msg, iov, 1, dnbd3_reply.size, msg.msg_flags) != dnbd3_reply.size) - error_dev("FATAL: Cold not read CMD_SELECT_IMAGE payload on handshake."); - // handle/check reply payload - serializer_reset_read(&dev->payload_buffer, dnbd3_reply.size); - dev->cur_server.protocol_version = serializer_get_uint16(&dev->payload_buffer); - if (dev->cur_server.protocol_version < MIN_SUPPORTED_SERVER) - error_dev("FATAL: Server version is lower than min supported version."); - name = serializer_get_string(&dev->payload_buffer); - if (dev->rid != 0 && strcmp(name, dev->imgname) != 0) - error_dev_va("FATAL: Server offers image '%s', requested '%s'", name, dev->imgname); - if (strlen(dev->imgname) < strlen(name)) - { - dev->imgname = krealloc(dev->imgname, strlen(name) + 1, GFP_ATOMIC ); - if (dev->imgname == NULL ) - error_dev("FATAL: Reallocating buffer for new image name failed"); - } - strcpy(dev->imgname, name); - rid = serializer_get_uint16(&dev->payload_buffer); - if (dev->rid != 0 && dev->rid != rid) - error_dev_va("FATAL: Server provides rid %d, requested was %d.", (int)rid, (int)dev->rid); - dev->rid = rid; - dev->reported_size = serializer_get_uint64(&dev->payload_buffer); - if (dev->reported_size < 4096) - error_dev("ERROR: Reported size by server is < 4096"); - // store image information - set_capacity(dev->disk, dev->reported_size >> 9); /* 512 Byte blocks */ - debug_dev_va("INFO: Filesize: %llu.", dev->reported_size); - dev->update_available = 0; - } - else // Switching server, connection is already established and size request was executed - { - debug_dev("INFO: On-the-fly server change."); - dev->sock = dev->better_sock; - dev->better_sock = NULL; - kernel_setsockopt(dev->sock, SOL_SOCKET, SO_SNDTIMEO, (char *)&timeout, sizeof(timeout)); - kernel_setsockopt(dev->sock, SOL_SOCKET, SO_RCVTIMEO, (char *)&timeout, sizeof(timeout)); - } +static void dnbd3_start_discover(dnbd3_device_t *dev, bool panic); - dev->panic = 0; - dev->panic_count = 0; +static void dnbd3_discover(dnbd3_device_t *dev); - // Enqueue request to request_queue_send for a fresh list of alt servers - dnbd3_cmd_to_priv(req1, CMD_GET_SERVERS); - list_add(&req1->queuelist, &dev->request_queue_send); +static void dnbd3_internal_discover(dnbd3_device_t *dev); - // create required threads - dev->thread_send = kthread_create(dnbd3_net_send, dev, dev->disk->disk_name); - dev->thread_receive = kthread_create(dnbd3_net_receive, dev, dev->disk->disk_name); - dev->thread_discover = kthread_create(dnbd3_net_discover, dev, dev->disk->disk_name); - // start them up - wake_up_process(dev->thread_send); - wake_up_process(dev->thread_receive); - wake_up_process(dev->thread_discover); +static void set_socket_timeout(struct socket *sock, bool set_send, int timeout_ms); - wake_up(&dev->process_queue_send); +// Use as write-only dump, don't care about race conditions etc. +static u8 __garbage_mem[PAGE_SIZE]; - // add heartbeat timer - dev->heartbeat_count = 0; +/** + * Delayed work triggering sending of keepalive packet. + */ +static void dnbd3_keepalive_workfn(struct work_struct *work) +{ + unsigned long irqflags; + dnbd3_device_t *dev = container_of(work, dnbd3_device_t, keepalive_work.work); -// init_timer_key changed from kernel version 4.14 to 4.15, see and compare to 4.15: -// https://elixir.bootlin.com/linux/v4.14.32/source/include/linux/timer.h#L98 -#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 15, 0) - timer_setup(&dev->hb_timer, dnbd3_net_heartbeat, 0); -#else - // Old timer setup - init_timer(&dev->hb_timer); - dev->hb_timer.data = (unsigned long)dev; - dev->hb_timer.function = dnbd3_net_heartbeat; -#endif - dev->hb_timer.expires = jiffies + HZ; - add_timer(&dev->hb_timer); - return 0; - error: ; - if (dev->sock) - { - sock_release(dev->sock); - dev->sock = NULL; + dnbd3_send_empty_request(dev, CMD_KEEPALIVE); + spin_lock_irqsave(&dev->blk_lock, irqflags); + if (device_active(dev)) { + mod_delayed_work(system_freezable_power_efficient_wq, + &dev->keepalive_work, KEEPALIVE_INTERVAL * HZ); } - dev->cur_server.host.type = 0; - dev->cur_server.host.port = 0; - if (req1) - kfree(req1); - return -1; + spin_unlock_irqrestore(&dev->blk_lock, irqflags); } -int dnbd3_net_disconnect(dnbd3_device_t *dev) +/** + * Delayed work triggering discovery (alt server check) + */ +static void dnbd3_discover_workfn(struct work_struct *work) { - if (dev->disconnecting) - return 0; - - if (dev->cur_server.host.port) - debug_dev("INFO: Disconnecting device."); - - dev->disconnecting = 1; - - // clear heartbeat timer - del_timer(&dev->hb_timer); - - dev->discover = 0; - - if (dev->sock) - kernel_sock_shutdown(dev->sock, SHUT_RDWR); - - // kill sending and receiving threads - if (dev->thread_send) - { - kthread_stop(dev->thread_send); - } + dnbd3_device_t *dev = container_of(work, dnbd3_device_t, discover_work.work); - if (dev->thread_receive) - { - kthread_stop(dev->thread_receive); - } + dnbd3_discover(dev); +} - if (dev->thread_discover) - { - kthread_stop(dev->thread_discover); - dev->thread_discover = NULL; - } +/** + * For manually triggering an immediate discovery + */ +static void dnbd3_start_discover(dnbd3_device_t *dev, bool panic) +{ + unsigned long irqflags; - // clear socket - if (dev->sock) - { - sock_release(dev->sock); - dev->sock = NULL; + if (!device_active(dev)) + return; + if (panic && dnbd3_flag_get(dev->connection_lock)) { + spin_lock_irqsave(&dev->blk_lock, irqflags); + if (!dev->panic) { + // Panic freshly turned on + dev->panic = true; + dev->discover_interval = TIMER_INTERVAL_PROBE_PANIC; + } + spin_unlock_irqrestore(&dev->blk_lock, irqflags); + dnbd3_flag_reset(dev->connection_lock); } - dev->cur_server.host.type = 0; - dev->cur_server.host.port = 0; - - dev->disconnecting = 0; - - return 0; + spin_lock_irqsave(&dev->blk_lock, irqflags); + mod_delayed_work(system_freezable_power_efficient_wq, + &dev->discover_work, 1); + spin_unlock_irqrestore(&dev->blk_lock, irqflags); } -#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 15, 0) -void dnbd3_net_heartbeat(struct timer_list *arg) -{ - dnbd3_device_t *dev = (dnbd3_device_t *)container_of(arg, dnbd3_device_t, hb_timer); -#else -void dnbd3_net_heartbeat(unsigned long arg) +/** + * Wrapper for the actual discover function below. Check run conditions + * here and re-schedule delayed task here. + */ +static void dnbd3_discover(dnbd3_device_t *dev) { - dnbd3_device_t *dev = (dnbd3_device_t *)arg; -#endif - // Because different events need different intervals, the timer is called once a second. - // Other intervals can be derived using dev->heartbeat_count. -#define timeout_seconds(x) (dev->heartbeat_count % (x) == 0) - - if (!dev->panic) - { - if (timeout_seconds(TIMER_INTERVAL_KEEPALIVE_PACKET)) - { - struct request *req = kmalloc(sizeof(struct request), GFP_ATOMIC ); - // send keepalive - if (req) - { - dnbd3_cmd_to_priv(req, CMD_KEEPALIVE); - list_add_tail(&req->queuelist, &dev->request_queue_send); - wake_up(&dev->process_queue_send); - } - else - { - debug_dev("ERROR: Couldn't create keepalive request."); - } - } - if ((dev->heartbeat_count > STARTUP_MODE_DURATION && timeout_seconds(TIMER_INTERVAL_PROBE_NORMAL)) - || (dev->heartbeat_count <= STARTUP_MODE_DURATION && timeout_seconds(TIMER_INTERVAL_PROBE_STARTUP))) - { - // Normal discovery - dev->discover = 1; - wake_up(&dev->process_queue_discover); + unsigned long irqflags; + + if (!device_active(dev) || dnbd3_flag_taken(dev->connection_lock)) + return; // device not active anymore, or just about to switch + if (!dnbd3_flag_get(dev->discover_running)) + return; // Already busy + spin_lock_irqsave(&dev->blk_lock, irqflags); + cancel_delayed_work(&dev->discover_work); + spin_unlock_irqrestore(&dev->blk_lock, irqflags); + dnbd3_internal_discover(dev); + dev->discover_count++; + // Re-queueing logic + spin_lock_irqsave(&dev->blk_lock, irqflags); + if (device_active(dev)) { + mod_delayed_work(system_freezable_power_efficient_wq, + &dev->discover_work, dev->discover_interval * HZ); + if (dev->discover_interval < TIMER_INTERVAL_PROBE_MAX + && dev->discover_count > DISCOVER_STARTUP_PHASE_COUNT) { + dev->discover_interval += 2; } } - else if (timeout_seconds(TIMER_INTERVAL_PROBE_PANIC)) - { - // Panic discovery - dev->discover = 1; - wake_up(&dev->process_queue_discover); - } - - dev->hb_timer.expires = jiffies + HZ; - - ++dev->heartbeat_count; - add_timer(&dev->hb_timer); -#undef timeout_seconds + spin_unlock_irqrestore(&dev->blk_lock, irqflags); + dnbd3_flag_reset(dev->discover_running); } -int dnbd3_net_discover(void *data) +/** + * Discovery. Probe all (or some) known alt servers, + * and initiate connection switch if appropriate + */ +static void dnbd3_internal_discover(dnbd3_device_t *dev) { - dnbd3_device_t *dev = data; - struct sockaddr_in sin4; - struct sockaddr_in6 sin6; struct socket *sock, *best_sock = NULL; + dnbd3_alt_server_t *alt; + struct sockaddr_storage host_compare, best_server; + uint16_t remote_version; + ktime_t start, end; + unsigned long rtt = 0, best_rtt = 0; + int i, j, k, isize, fails, rtt_threshold; + int do_change = 0; + u8 check_order[NUMBER_SERVERS]; + const bool ready = dev->discover_count > DISCOVER_STARTUP_PHASE_COUNT; + const u32 turn = dev->discover_count % DISCOVER_HISTORY_SIZE; + + // Shuffle alt_servers + for (i = 0; i < NUMBER_SERVERS; ++i) + check_order[i] = i; - dnbd3_request_t dnbd3_request; - dnbd3_reply_t dnbd3_reply; - dnbd3_server_t *alt_server; - struct msghdr msg; - struct kvec iov[2]; - - char *buf, *name; - serialized_buffer_t *payload; - uint64_t filesize; - uint16_t rid; - - struct timeval start, end; - unsigned long rtt, best_rtt = 0; - unsigned long irqflags; - int i, j, isize, best_server, current_server; - int turn = 0; - int ready = 0, do_change = 0; - char check_order[NUMBER_SERVERS]; - int mlen; - - struct request *last_request = (struct request *)123, *cur_request = (struct request *)456; - - struct timeval timeout; - timeout.tv_sec = SOCKET_TIMEOUT_CLIENT_DISCOVERY; - timeout.tv_usec = 0; - - memset(&sin4, 0, sizeof(sin4)); - memset(&sin6, 0, sizeof(sin6)); - - init_msghdr(msg); + for (i = 0; i < NUMBER_SERVERS; ++i) { + j = get_random_u32() % NUMBER_SERVERS; + if (j != i) { + int tmp = check_order[i]; - buf = kmalloc(4096, GFP_KERNEL); - if (!buf) - { - debug_dev("FATAL: Kmalloc failed (discover)"); - return -1; + check_order[i] = check_order[j]; + check_order[j] = tmp; + } } - payload = (serialized_buffer_t *)buf; // Reuse this buffer to save kernel mem - dnbd3_request.magic = dnbd3_packet_magic; + best_server.ss_family = 0; + best_rtt = RTT_UNREACHABLE; - for (i = 0; i < NUMBER_SERVERS; ++i) { - check_order[i] = i; - } - - for (;;) - { - wait_event_interruptible(dev->process_queue_discover, - kthread_should_stop() || dev->discover || dev->thread_discover == NULL); + if (!ready || dev->panic) + isize = NUMBER_SERVERS; + else + isize = 3; - if (kthread_should_stop() || dev->imgname == NULL || dev->thread_discover == NULL ) + for (j = 0; j < NUMBER_SERVERS; ++j) { + if (!device_active(dev)) break; + i = check_order[j]; + mutex_lock(&dev->alt_servers_lock); + host_compare = dev->alt_servers[i].host; + fails = dev->alt_servers[i].failures; + mutex_unlock(&dev->alt_servers_lock); + if (host_compare.ss_family == 0) + continue; // Empty slot + // Reduced probability for hosts that have been unreachable + if (!dev->panic && fails > 50 && (get_random_u32() % 4) != 0) + continue; // If not in panic mode, skip server if it failed too many times + if (isize-- <= 0 && !is_same_server(&dev->cur_server.host, &host_compare)) + continue; // Only test isize servers plus current server + + // Initialize socket and connect + sock = NULL; + if (dnbd3_connect(dev, &host_compare, &sock) != 0) + goto error; - if (!dev->discover) - continue; - dev->discover = 0; - - if (dev->reported_size < 4096) - continue; - - // Check if the list of alt servers needs to be updated and do so if necessary - if (dev->new_servers_num) - { - spin_lock_irqsave(&dev->blk_lock, irqflags); - for (i = 0; i < dev->new_servers_num; ++i) - { - if (dev->new_servers[i].host.type != HOST_IP4 && dev->new_servers[i].host.type != HOST_IP6) // Invalid entry? - continue; - alt_server = get_existing_server(&dev->new_servers[i], dev); - if (alt_server != NULL ) // Server already known - { - if (dev->new_servers[i].failures == 1) - { - // REMOVE request - if (alt_server->host.type == HOST_IP4) - debug_dev_va("Removing alt server %pI4", alt_server->host.addr); - else - debug_dev_va("Removing alt server %pI6", alt_server->host.addr); - alt_server->host.type = 0; - continue; - } - // ADD, so just reset fail counter - alt_server->failures = 0; - continue; - } - if (dev->new_servers[i].failures == 1) // REMOVE, but server is not in list anyways - continue; - alt_server = get_free_alt_server(dev); - if (alt_server == NULL ) // All NUMBER_SERVERS slots are taken, ignore entry - continue; - // Add new server entry - alt_server->host = dev->new_servers[i].host; - if (alt_server->host.type == HOST_IP4) - debug_dev_va("Adding alt server %pI4", alt_server->host.addr); - else - debug_dev_va("Adding alt server %pI6", alt_server->host.addr); - alt_server->rtts[0] = alt_server->rtts[1] = alt_server->rtts[2] = alt_server->rtts[3] = RTT_UNREACHABLE; - alt_server->protocol_version = 0; - alt_server->failures = 0; - } - dev->new_servers_num = 0; - spin_unlock_irqrestore(&dev->blk_lock, irqflags); - } + remote_version = 0; + if (!dnbd3_execute_handshake(dev, sock, &host_compare, &remote_version, false)) + goto error; - current_server = best_server = -1; - best_rtt = 0xFFFFFFFul; - if (dev->heartbeat_count < STARTUP_MODE_DURATION || dev->panic) - { - isize = NUMBER_SERVERS; - } - else - { - isize = 3; - } - if (NUMBER_SERVERS > isize) { - for (i = 0; i < isize; ++i) { - j = ((start.tv_sec >> i) ^ (start.tv_usec >> j)) % NUMBER_SERVERS; - if (j != i) { - mlen = check_order[i]; - check_order[i] = check_order[j]; - check_order[j] = mlen; - } + // panic mode, take first responding server + if (dev->panic) { + dnbd3_dev_info_host(dev, &host_compare, "panic mode, changing to new server\n"); + if (!dnbd3_flag_get(dev->connection_lock)) { + dnbd3_dev_info_host(dev, &host_compare, "...raced, ignoring\n"); + } else { + // Check global flag, a connect might have been in progress + if (best_sock != NULL) + sock_release(best_sock); + set_socket_timeout(sock, false, SOCKET_TIMEOUT_RECV * 1000 + 1000); + if (dnbd3_set_primary_connection(dev, sock, &host_compare, remote_version) != 0) + sock_release(sock); + dnbd3_flag_reset(dev->connection_lock); + return; } } - for (j = 0; j < NUMBER_SERVERS; ++j) - { - i = check_order[j]; - if (dev->alt_servers[i].host.type == 0) // Empty slot - continue; - if (!dev->panic && dev->alt_servers[i].failures > 50 && (start.tv_usec & 7) != 0) // If not in panic mode, skip server if it failed too many times - continue; - if (isize-- <= 0 && !is_same_server(&dev->cur_server, &dev->alt_servers[i])) - continue; - - // Initialize socket and connect - if (dnbd3_sock_create(dev->alt_servers[i].host.type, SOCK_STREAM, IPPROTO_TCP, &sock) < 0) - { - debug_alt("ERROR: Couldn't create socket (discover)."); - sock = NULL; - continue; - } - kernel_setsockopt(sock, SOL_SOCKET, SO_SNDTIMEO, (char *)&timeout, sizeof(timeout)); - kernel_setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO, (char *)&timeout, sizeof(timeout)); - sock->sk->sk_allocation = GFP_NOIO; - if (dev->alt_servers[i].host.type == HOST_IP4) - { - sin4.sin_family = AF_INET; - memcpy(&sin4.sin_addr, dev->alt_servers[i].host.addr, 4); - sin4.sin_port = dev->alt_servers[i].host.port; - if (kernel_connect(sock, (struct sockaddr *)&sin4, sizeof(sin4), 0) < 0) - goto error; - } - else - { - sin6.sin6_family = AF_INET6; - memcpy(&sin6.sin6_addr, dev->alt_servers[i].host.addr, 16); - sin6.sin6_port = dev->alt_servers[i].host.port; - if (kernel_connect(sock, (struct sockaddr *)&sin6, sizeof(sin6), 0) < 0) - goto error; - } + // actual rtt measurement is just the first block requests and reply + start = ktime_get_real(); + if (!dnbd3_request_test_block(dev, &host_compare, sock)) + goto error; + end = ktime_get_real(); - // Request filesize - dnbd3_request.cmd = CMD_SELECT_IMAGE; - iov[0].iov_base = &dnbd3_request; - iov[0].iov_len = sizeof(dnbd3_request); - serializer_reset_write(payload); - serializer_put_uint16(payload, PROTOCOL_VERSION); // DNBD3 protocol version - serializer_put_string(payload, dev->imgname); // image name - serializer_put_uint16(payload, dev->rid); // revision id - serializer_put_uint8(payload, 0); // are we a server? (no!) - iov[1].iov_base = payload; - dnbd3_request.size = iov[1].iov_len = serializer_get_written_length(payload); - fixup_request(dnbd3_request); - mlen = iov[1].iov_len + sizeof(dnbd3_request); - if (kernel_sendmsg(sock, &msg, iov, 2, mlen) != mlen) - error_alt("ERROR: Requesting image size failed."); - - // receive net reply - iov[0].iov_base = &dnbd3_reply; - iov[0].iov_len = sizeof(dnbd3_reply); - if (kernel_recvmsg(sock, &msg, iov, 1, sizeof(dnbd3_reply), msg.msg_flags) != sizeof(dnbd3_reply)) - error_alt("ERROR: Receiving image size packet (header) failed (discover)."); - fixup_reply(dnbd3_reply); - if (dnbd3_reply.magic != dnbd3_packet_magic || dnbd3_reply.cmd != CMD_SELECT_IMAGE || dnbd3_reply.size < 4) - error_alt("ERROR: Content of image size packet (header) mismatched (discover)."); - - // receive data - iov[0].iov_base = payload; - iov[0].iov_len = dnbd3_reply.size; - if (kernel_recvmsg(sock, &msg, iov, 1, dnbd3_reply.size, msg.msg_flags) != dnbd3_reply.size) - error_alt("ERROR: Receiving image size packet (payload) failed (discover)."); - serializer_reset_read(payload, dnbd3_reply.size); - - dev->alt_servers[i].protocol_version = serializer_get_uint16(payload); - if (dev->alt_servers[i].protocol_version < MIN_SUPPORTED_SERVER) - error_alt_va("ERROR: Server version too old (client: %d, server: %d, min supported: %d).", - (int)PROTOCOL_VERSION, (int)dev->alt_servers[i].protocol_version, (int)MIN_SUPPORTED_SERVER); - - name = serializer_get_string(payload); - if (name == NULL ) - error_alt("ERROR: Server did not supply an image name (discover)."); - - if (strcmp(name, dev->imgname) != 0) - error_alt_va("ERROR: Image name does not match requested one (client: '%s', server: '%s') (discover).", - dev->imgname, name); - - rid = serializer_get_uint16(payload); - if (rid != dev->rid) - error_alt_va("ERROR: Server supplied wrong rid (client: '%d', server: '%d') (discover).", - (int)dev->rid, (int)rid); - - filesize = serializer_get_uint64(payload); - if (filesize != dev->reported_size) - error_alt_va("ERROR: Reported image size of %llu does not match expected value %llu.(discover).", - (unsigned long long)filesize, (unsigned long long)dev->reported_size); - - // panic mode, take first responding server - if (dev->panic) - { - dev->panic = 0; - debug_alt("WARN: Panic mode, changing server:"); - if (best_sock != NULL ) - sock_release(best_sock); - dev->better_sock = sock; // Pass over socket to take a shortcut in *_connect(); - kfree(buf); - dev->thread_discover = NULL; - dnbd3_net_disconnect(dev); - memcpy(&dev->cur_server, &dev->alt_servers[i], sizeof(dev->cur_server)); - dnbd3_net_connect(dev); - return 0; - } + mutex_lock(&dev->alt_servers_lock); + if (is_same_server(&dev->alt_servers[i].host, &host_compare)) { + dev->alt_servers[i].protocol_version = remote_version; + dev->alt_servers[i].rtts[turn] = + (unsigned long)ktime_us_delta(end, start); - // Request block - dnbd3_request.cmd = CMD_GET_BLOCK; - // Do *NOT* pick a random block as it has proven to cause severe - // cache thrashing on the server - dnbd3_request.offset = 0; - dnbd3_request.size = RTT_BLOCK_SIZE; - fixup_request(dnbd3_request); - iov[0].iov_base = &dnbd3_request; - iov[0].iov_len = sizeof(dnbd3_request); - - // start rtt measurement - do_gettimeofday(&start); - - if (kernel_sendmsg(sock, &msg, iov, 1, sizeof(dnbd3_request)) <= 0) - error_alt("ERROR: Requesting test block failed (discover)."); - - // receive net reply - iov[0].iov_base = &dnbd3_reply; - iov[0].iov_len = sizeof(dnbd3_reply); - if (kernel_recvmsg(sock, &msg, iov, 1, sizeof(dnbd3_reply), msg.msg_flags) != sizeof(dnbd3_reply)) - error_alt("ERROR: Receiving test block header packet failed (discover)."); - fixup_reply(dnbd3_reply); - if (dnbd3_reply.magic - != dnbd3_packet_magic|| dnbd3_reply.cmd != CMD_GET_BLOCK || dnbd3_reply.size != RTT_BLOCK_SIZE) - error_alt_va("ERROR: Unexpected reply to block request: cmd=%d, size=%d (discover).", - (int)dnbd3_reply.cmd, (int)dnbd3_reply.size); - - // receive data - iov[0].iov_base = buf; - iov[0].iov_len = RTT_BLOCK_SIZE; - if (kernel_recvmsg(sock, &msg, iov, 1, dnbd3_reply.size, msg.msg_flags) != RTT_BLOCK_SIZE) - error_alt("ERROR: Receiving test block payload failed (discover)."); - - do_gettimeofday(&end); // end rtt measurement - - dev->alt_servers[i].rtts[turn] = (unsigned long)((end.tv_sec - start.tv_sec) * 1000000ull - + (end.tv_usec - start.tv_usec)); - - rtt = (dev->alt_servers[i].rtts[0] + dev->alt_servers[i].rtts[1] + dev->alt_servers[i].rtts[2] - + dev->alt_servers[i].rtts[3]) / 4; - - if (best_rtt > rtt) - { - // This one is better, keep socket open in case we switch - best_rtt = rtt; - best_server = i; - if (best_sock != NULL ) - sock_release(best_sock); - best_sock = sock; - sock = NULL; - } - else - { - // Not better, discard connection - sock_release(sock); - sock = NULL; - } + rtt = 0; - // update cur servers rtt - if (is_same_server(&dev->cur_server, &dev->alt_servers[i])) - { - dev->cur_rtt = rtt; - current_server = i; - } + for (k = 0; k < DISCOVER_HISTORY_SIZE; ++k) + rtt += dev->alt_servers[i].rtts[k]; + rtt /= DISCOVER_HISTORY_SIZE; dev->alt_servers[i].failures = 0; + if (dev->alt_servers[i].best_count > 1) + dev->alt_servers[i].best_count -= 2; + } + mutex_unlock(&dev->alt_servers_lock); - continue; - - error: ; - ++dev->alt_servers[i].failures; + if (best_rtt > rtt) { + // This one is better, keep socket open in case we switch + best_rtt = rtt; + best_server = host_compare; + if (best_sock != NULL) + sock_release(best_sock); + best_sock = sock; + sock = NULL; + } else { + // Not better, discard connection sock_release(sock); sock = NULL; - dev->alt_servers[i].rtts[turn] = RTT_UNREACHABLE; - if (is_same_server(&dev->cur_server, &dev->alt_servers[i])) - { - dev->cur_rtt = RTT_UNREACHABLE; - current_server = i; - } - continue; } - if (dev->panic) - { - // After 21 retries, bail out by reporting errors to block layer - if (PROBE_COUNT_TIMEOUT > 0 && dev->panic_count < 255 && ++dev->panic_count == PROBE_COUNT_TIMEOUT + 1) - dnbd3_blk_fail_all_requests(dev); - } + // update cur servers rtt + if (is_same_server(&dev->cur_server.host, &host_compare)) + dev->cur_server.rtt = rtt; - if (best_server == -1 || kthread_should_stop() || dev->thread_discover == NULL ) // No alt server could be reached at all or thread should stop - { - if (best_sock != NULL ) // Should never happen actually - { - sock_release(best_sock); - best_sock = NULL; - } - continue; - } + continue; - do_change = ready && best_server != current_server && (start.tv_usec & 3) != 0 - && RTT_THRESHOLD_FACTOR(dev->cur_rtt) > best_rtt + 1500; - - if (ready && !do_change) { - spin_lock_irqsave(&dev->blk_lock, irqflags); - if (!list_empty(&dev->request_queue_send)) - { - cur_request = list_entry(dev->request_queue_send.next, struct request, queuelist); - do_change = (cur_request == last_request); - if (do_change) - printk("WARNING: Hung request on %s\n", dev->disk->disk_name); - } - else - { - cur_request = (struct request *)123; - } - last_request = cur_request; - spin_unlock_irqrestore(&dev->blk_lock, irqflags); +error: + if (sock != NULL) { + sock_release(sock); + sock = NULL; } - - // take server with lowest rtt - if (do_change) - { - printk("INFO: Server %d on %s is faster (%lluµs vs. %lluµs)\n", best_server, dev->disk->disk_name, - (unsigned long long)best_rtt, (unsigned long long)dev->cur_rtt); - kfree(buf); - dev->better_sock = best_sock; // Take shortcut by continuing to use open connection - dev->thread_discover = NULL; - dnbd3_net_disconnect(dev); - memcpy(&dev->cur_server, &dev->alt_servers[best_server], sizeof(dev->cur_server)); - dev->cur_rtt = best_rtt; - dnbd3_net_connect(dev); - return 0; + mutex_lock(&dev->alt_servers_lock); + if (is_same_server(&dev->alt_servers[i].host, &host_compare)) { + if (remote_version) + dev->alt_servers[i].protocol_version = remote_version; + ++dev->alt_servers[i].failures; + dev->alt_servers[i].rtts[turn] = RTT_UNREACHABLE; + if (dev->alt_servers[i].best_count > 2) + dev->alt_servers[i].best_count -= 3; } - - // Clean up connection that was held open for quicker server switch - if (best_sock != NULL ) - { - sock_release(best_sock); - best_sock = NULL; + mutex_unlock(&dev->alt_servers_lock); + if (is_same_server(&dev->cur_server.host, &host_compare)) + dev->cur_server.rtt = RTT_UNREACHABLE; + } // END - for loop over alt_servers + + if (best_server.ss_family == 0) { + // No alt server could be reached + ASSERT(!best_sock); + if (dev->panic) { + if (dev->panic_count < 255) + dev->panic_count++; + // If probe timeout is set, report error to block layer + if (PROBE_COUNT_TIMEOUT > 0 && dev->panic_count == PROBE_COUNT_TIMEOUT + 1) + dnbd3_blk_fail_all_requests(dev); } + return; + } - if (!ready || (start.tv_usec & 15) != 0) - turn = (turn + 1) % 4; - if (turn == 2) // Set ready when we only have 2 of 4 measurements for quicker load balancing - ready = 1; - + // If best server was repeatedly measured best, lower the switching threshold more + mutex_lock(&dev->alt_servers_lock); + alt = get_existing_alt_from_addr(&best_server, dev); + if (alt != NULL) { + if (alt->best_count < 178) + alt->best_count += 3; + rtt_threshold = 1800 - (alt->best_count * 10); + remote_version = alt->protocol_version; + } else { + rtt_threshold = 1800; + remote_version = 0; } - kfree(buf); - return 0; + mutex_unlock(&dev->alt_servers_lock); + + do_change = ready && !is_same_server(&best_server, &dev->cur_server.host) + && RTT_THRESHOLD_FACTOR(dev->cur_server.rtt) > best_rtt + rtt_threshold; + + // take server with lowest rtt + // if a (dis)connect is already in progress, we do nothing, this is not panic mode + if (do_change && device_active(dev) && dnbd3_flag_get(dev->connection_lock)) { + dnbd3_dev_info_cur(dev, "server %pISpc is faster (%lluµs vs. %lluµs)\n", + &best_server, + (unsigned long long)best_rtt, (unsigned long long)dev->cur_server.rtt); + set_socket_timeout(best_sock, false, // recv + MAX(best_rtt / 1000, SOCKET_TIMEOUT_RECV * 1000) + 500); + set_socket_timeout(best_sock, true, // send + MAX(best_rtt / 1000, SOCKET_TIMEOUT_SEND * 1000) + 500); + if (dnbd3_set_primary_connection(dev, best_sock, &best_server, remote_version) != 0) + sock_release(best_sock); + dnbd3_flag_reset(dev->connection_lock); + return; + } + + // Clean up connection that was held open for quicker server switch + if (best_sock != NULL) + sock_release(best_sock); } -int dnbd3_net_send(void *data) +/** + * Worker for sending pending requests. This will be triggered whenever + * we get a new request from the block layer. The worker will then + * work through all the requests in the send queue, request them from + * the server, and return again. + */ +static void dnbd3_send_workfn(struct work_struct *work) { - dnbd3_device_t *dev = data; - struct request *blk_request, *tmp_request; - - dnbd3_request_t dnbd3_request; - struct msghdr msg; - struct kvec iov; - + dnbd3_device_t *dev = container_of(work, dnbd3_device_t, send_work); + struct request *blk_request; + struct dnbd3_cmd *cmd; unsigned long irqflags; - init_msghdr(msg); - - dnbd3_request.magic = dnbd3_packet_magic; - - set_user_nice(current, -20); - - // move already sent requests to request_queue_send again - while (!list_empty(&dev->request_queue_receive)) - { - printk("WARN: Request queue was not empty on %s\n", dev->disk->disk_name); - spin_lock_irqsave(&dev->blk_lock, irqflags); - list_for_each_entry_safe(blk_request, tmp_request, &dev->request_queue_receive, queuelist) - { - list_del_init(&blk_request->queuelist); - list_add(&blk_request->queuelist, &dev->request_queue_send); - } - spin_unlock_irqrestore(&dev->blk_lock, irqflags); - } - - for (;;) - { - wait_event_interruptible(dev->process_queue_send, kthread_should_stop() || !list_empty(&dev->request_queue_send)); - - if (kthread_should_stop()) + mutex_lock(&dev->send_mutex); + while (dev->sock && device_active(dev)) { + // extract next block request + spin_lock_irqsave(&dev->send_queue_lock, irqflags); + if (list_empty(&dev->send_queue)) { + spin_unlock_irqrestore(&dev->send_queue_lock, irqflags); break; - - // extract block request - spin_lock_irqsave(&dev->blk_lock, irqflags); - if (list_empty(&dev->request_queue_send)) - { - spin_unlock_irqrestore(&dev->blk_lock, irqflags); - continue; } - blk_request = list_entry(dev->request_queue_send.next, struct request, queuelist); - spin_unlock_irqrestore(&dev->blk_lock, irqflags); - // what to do? - switch (dnbd3_req_op(blk_request)) - { - case DNBD3_DEV_READ: - dnbd3_request.cmd = CMD_GET_BLOCK; - dnbd3_request.offset = blk_rq_pos(blk_request) << 9; // *512 - dnbd3_request.size = blk_rq_bytes(blk_request); // bytes left to complete entire request - // enqueue request to request_queue_receive - spin_lock_irqsave(&dev->blk_lock, irqflags); - list_del_init(&blk_request->queuelist); - list_add_tail(&blk_request->queuelist, &dev->request_queue_receive); - spin_unlock_irqrestore(&dev->blk_lock, irqflags); - break; - case DNBD3_REQ_OP_SPECIAL: - dnbd3_request.cmd = dnbd3_priv_to_cmd(blk_request); - dnbd3_request.size = 0; - spin_lock_irqsave(&dev->blk_lock, irqflags); - list_del_init(&blk_request->queuelist); - spin_unlock_irqrestore(&dev->blk_lock, irqflags); + blk_request = list_entry(dev->send_queue.next, struct request, queuelist); + list_del_init(&blk_request->queuelist); + spin_unlock_irqrestore(&dev->send_queue_lock, irqflags); + // append to receive queue + spin_lock_irqsave(&dev->recv_queue_lock, irqflags); + list_add_tail(&blk_request->queuelist, &dev->recv_queue); + spin_unlock_irqrestore(&dev->recv_queue_lock, irqflags); + + cmd = blk_mq_rq_to_pdu(blk_request); + if (!dnbd3_send_request(dev->sock, CMD_GET_BLOCK, cmd->handle, + blk_rq_pos(blk_request) << 9 /* sectors */, blk_rq_bytes(blk_request))) { + if (!dnbd3_flag_taken(dev->connection_lock)) { + dnbd3_dev_err_cur(dev, "connection to server lost (send)\n"); + dnbd3_start_discover(dev, true); + } break; - - default: - printk("ERROR: Unknown command (send %u %u)\n", (int)blk_request->cmd_flags, (int)dnbd3_req_op(blk_request)); - spin_lock_irqsave(&dev->blk_lock, irqflags); - list_del_init(&blk_request->queuelist); - spin_unlock_irqrestore(&dev->blk_lock, irqflags); - continue; } - - // send net request - dnbd3_request.handle = (uint64_t)(uintptr_t)blk_request; // Double cast to prevent warning on 32bit - fixup_request(dnbd3_request); - iov.iov_base = &dnbd3_request; - iov.iov_len = sizeof(dnbd3_request); - if (kernel_sendmsg(dev->sock, &msg, &iov, 1, sizeof(dnbd3_request)) != sizeof(dnbd3_request)) - { - debug_dev("ERROR: Connection to server lost (send)"); - goto error; - } - wake_up(&dev->process_queue_receive); } - - dev->thread_send = NULL; - return 0; - - error: ; - if (dev->sock) - kernel_sock_shutdown(dev->sock, SHUT_RDWR); - if (!dev->disconnecting) - { - dev->panic = 1; - dev->discover = 1; - wake_up(&dev->process_queue_discover); - } - dev->thread_send = NULL; - return -1; + mutex_unlock(&dev->send_mutex); } -int dnbd3_net_receive(void *data) +/** + * The receive workfn stays active for as long as the connection to a server + * lasts, i.e. it only gets restarted when we switch to a new server. + */ +static void dnbd3_recv_workfn(struct work_struct *work) { - dnbd3_device_t *dev = data; - struct request *blk_request, *tmp_request, *received_request; - - dnbd3_reply_t dnbd3_reply; - struct msghdr msg; - struct kvec iov; + dnbd3_device_t *dev = container_of(work, dnbd3_device_t, recv_work); + struct request *blk_request; + struct request *rq_iter; + struct dnbd3_cmd *cmd; + dnbd3_reply_t reply_hdr; struct req_iterator iter; struct bio_vec bvec_inst; struct bio_vec *bvec = &bvec_inst; + struct msghdr msg = { .msg_flags = MSG_NOSIGNAL | MSG_WAITALL }; + struct kvec iov; void *kaddr; unsigned long irqflags; - sigset_t blocked, oldset; uint16_t rid; - unsigned long int recv_timeout = jiffies; - - int count, remaining, ret; - - init_msghdr(msg); - set_user_nice(current, -20); + int remaining; + int ret; - while (!kthread_should_stop()) - { + mutex_lock(&dev->recv_mutex); + while (dev->sock) { // receive net reply - iov.iov_base = &dnbd3_reply; - iov.iov_len = sizeof(dnbd3_reply); - ret = kernel_recvmsg(dev->sock, &msg, &iov, 1, sizeof(dnbd3_reply), msg.msg_flags); - if (ret == -EAGAIN) - { - if (jiffies < recv_timeout) recv_timeout = jiffies; // Handle overflow - if ((jiffies - recv_timeout) / HZ > SOCKET_KEEPALIVE_TIMEOUT) - error_dev_va("ERROR: Receive timeout reached (%d of %d secs).", (int)((jiffies - recv_timeout) / HZ), (int)SOCKET_KEEPALIVE_TIMEOUT); - continue; + ret = dnbd3_recv_reply(dev->sock, &reply_hdr); + if (ret == 0) { + /* have not received any data, but remote peer is shutdown properly */ + dnbd3_dev_dbg_cur(dev, "remote peer has performed an orderly shutdown\n"); + goto out_unlock; + } else if (ret < 0) { + if (ret == -EAGAIN) { + if (!dnbd3_flag_taken(dev->connection_lock)) + dnbd3_dev_err_cur(dev, "receive timeout reached\n"); + } else { + /* for all errors other than -EAGAIN, print errno */ + if (!dnbd3_flag_taken(dev->connection_lock)) + dnbd3_dev_err_cur(dev, "connection to server lost (receive, errno=%d)\n", ret); + } + goto out_unlock; } - if (ret <= 0) - error_dev("ERROR: Connection to server lost (receive)"); - if (ret != sizeof(dnbd3_reply)) - error_dev("ERROR: Recv msg header."); - fixup_reply(dnbd3_reply); - // check error - if (dnbd3_reply.magic != dnbd3_packet_magic) - error_dev("ERROR: Wrong packet magic (Receive)."); - if (dnbd3_reply.cmd == 0) - error_dev("ERROR: Command was 0 (Receive)."); + /* check if arrived data is valid */ + if (ret != sizeof(reply_hdr)) { + if (!dnbd3_flag_taken(dev->connection_lock)) + dnbd3_dev_err_cur(dev, "recv partial msg header (%d/%d bytes)\n", + ret, (int)sizeof(reply_hdr)); + goto out_unlock; + } - // Update timeout - recv_timeout = jiffies; + // check error + if (reply_hdr.magic != dnbd3_packet_magic) { + dnbd3_dev_err_cur(dev, "wrong packet magic (receive)\n"); + goto out_unlock; + } // what to do? - switch (dnbd3_reply.cmd) - { + switch (reply_hdr.cmd) { case CMD_GET_BLOCK: // search for replied request in queue blk_request = NULL; - spin_lock_irqsave(&dev->blk_lock, irqflags); - list_for_each_entry_safe(received_request, tmp_request, &dev->request_queue_receive, queuelist) - { - if ((uint64_t)(uintptr_t)received_request == dnbd3_reply.handle) // Double cast to prevent warning on 32bit - { - blk_request = received_request; + spin_lock_irqsave(&dev->recv_queue_lock, irqflags); + list_for_each_entry(rq_iter, &dev->recv_queue, queuelist) { + cmd = blk_mq_rq_to_pdu(rq_iter); + if (cmd->handle == reply_hdr.handle) { + blk_request = rq_iter; + list_del_init(&blk_request->queuelist); break; } } - spin_unlock_irqrestore(&dev->blk_lock, irqflags); - if (blk_request == NULL ) - error_dev_va("ERROR: Received block data for unrequested handle (%llu: %llu).\n", - (unsigned long long)dnbd3_reply.handle, (unsigned long long)dnbd3_reply.size); + spin_unlock_irqrestore(&dev->recv_queue_lock, irqflags); + if (blk_request == NULL) { + dnbd3_dev_err_cur(dev, "received block data for unrequested handle (%llx: len=%llu)\n", + reply_hdr.handle, + (u64)reply_hdr.size); + goto out_unlock; + } // receive data and answer to block layer #if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 14, 0) - rq_for_each_segment(bvec_inst, blk_request, iter) + rq_for_each_segment(bvec_inst, blk_request, iter) { #else - rq_for_each_segment(bvec, blk_request, iter) + rq_for_each_segment(bvec, blk_request, iter) { #endif - { - siginitsetinv(&blocked, sigmask(SIGKILL)); - sigprocmask(SIG_SETMASK, &blocked, &oldset); - kaddr = kmap(bvec->bv_page) + bvec->bv_offset; iov.iov_base = kaddr; iov.iov_len = bvec->bv_len; - if (kernel_recvmsg(dev->sock, &msg, &iov, 1, bvec->bv_len, msg.msg_flags) != bvec->bv_len) - { - kunmap(bvec->bv_page); - sigprocmask(SIG_SETMASK, &oldset, NULL ); - error_dev("ERROR: Receiving from net to block layer."); - } + ret = kernel_recvmsg(dev->sock, &msg, &iov, 1, bvec->bv_len, msg.msg_flags); kunmap(bvec->bv_page); - - sigprocmask(SIG_SETMASK, &oldset, NULL ); + if (ret != bvec->bv_len) { + if (ret == 0) { + /* have not received any data, but remote peer is shutdown properly */ + dnbd3_dev_dbg_cur( + dev, "remote peer has performed an orderly shutdown\n"); + } else if (ret < 0) { + if (!dnbd3_flag_taken(dev->connection_lock)) + dnbd3_dev_err_cur(dev, + "disconnect: receiving from net to block layer\n"); + } else { + if (!dnbd3_flag_taken(dev->connection_lock)) + dnbd3_dev_err_cur(dev, + "receiving from net to block layer (%d bytes)\n", ret); + } + // Requeue request + spin_lock_irqsave(&dev->send_queue_lock, irqflags); + list_add(&blk_request->queuelist, &dev->send_queue); + spin_unlock_irqrestore(&dev->send_queue_lock, irqflags); + goto out_unlock; + } } - spin_lock_irqsave(&dev->blk_lock, irqflags); - list_del_init(&blk_request->queuelist); - __blk_end_request_all(blk_request, 0); - spin_unlock_irqrestore(&dev->blk_lock, irqflags); - continue; + blk_mq_end_request(blk_request, BLK_STS_OK); + break; case CMD_GET_SERVERS: - if (!dev->use_server_provided_alts) - { - remaining = dnbd3_reply.size; - goto consume_payload; - } - spin_lock_irqsave(&dev->blk_lock, irqflags); - dev->new_servers_num = 0; - spin_unlock_irqrestore(&dev->blk_lock, irqflags); - count = MIN(NUMBER_SERVERS, dnbd3_reply.size / sizeof(dnbd3_server_entry_t)); - - if (count != 0) - { - iov.iov_base = dev->new_servers; - iov.iov_len = count * sizeof(dnbd3_server_entry_t); - if (kernel_recvmsg(dev->sock, &msg, &iov, 1, (count * sizeof(dnbd3_server_entry_t)), msg.msg_flags) - != (count * sizeof(dnbd3_server_entry_t))) - error_dev("ERROR: Recv CMD_GET_SERVERS payload."); - spin_lock_irqsave(&dev->blk_lock, irqflags); - dev->new_servers_num = count; - spin_unlock_irqrestore(&dev->blk_lock, irqflags); - } - // If there were more servers than accepted, remove the remaining data from the socket buffer - remaining = dnbd3_reply.size - (count * sizeof(dnbd3_server_entry_t)); - consume_payload: while (remaining > 0) - { - count = MIN(sizeof(dnbd3_reply), remaining); // Abuse the reply struct as the receive buffer - iov.iov_base = &dnbd3_reply; - iov.iov_len = count; - ret = kernel_recvmsg(dev->sock, &msg, &iov, 1, iov.iov_len, msg.msg_flags); - if (ret <= 0) - error_dev("ERROR: Recv additional payload from CMD_GET_SERVERS."); - remaining -= ret; + remaining = reply_hdr.size; + if (dev->use_server_provided_alts) { + dnbd3_server_entry_t new_server; + + while (remaining >= sizeof(dnbd3_server_entry_t)) { + if (dnbd3_recv_bytes(dev->sock, &new_server, sizeof(new_server)) + != sizeof(new_server)) { + if (!dnbd3_flag_taken(dev->connection_lock)) + dnbd3_dev_err_cur(dev, "recv CMD_GET_SERVERS payload\n"); + goto out_unlock; + } + // TODO: Log + if (new_server.failures == 0) { // ADD + dnbd3_add_server(dev, &new_server.host); + } else { // REM + dnbd3_rem_server(dev, &new_server.host); + } + remaining -= sizeof(new_server); + } } - continue; + if (!dnbd3_drain_socket(dev, dev->sock, remaining)) + goto out_unlock; + break; case CMD_LATEST_RID: - if (dnbd3_reply.size != 2) - { - printk("ERROR: CMD_LATEST_RID.size != 2.\n"); + if (reply_hdr.size < 2) { + dev_err(dnbd3_device_to_dev(dev), "CMD_LATEST_RID.size < 2\n"); continue; } - iov.iov_base = &rid; - iov.iov_len = sizeof(rid); - if (kernel_recvmsg(dev->sock, &msg, &iov, 1, iov.iov_len, msg.msg_flags) <= 0) - { - printk("ERROR: Could not receive CMD_LATEST_RID payload.\n"); - } - else - { + if (dnbd3_recv_bytes(dev->sock, &rid, 2) != 2) { + if (!dnbd3_flag_taken(dev->connection_lock)) + dev_err(dnbd3_device_to_dev(dev), "could not receive CMD_LATEST_RID payload\n"); + } else { rid = net_order_16(rid); - printk("Latest rid of %s is %d (currently using %d)\n", dev->imgname, (int)rid, (int)dev->rid); + dnbd3_dev_info_cur(dev, "latest rid of %s is %d (currently using %d)\n", + dev->imgname, (int)rid, (int)dev->rid); dev->update_available = (rid > dev->rid ? 1 : 0); } + if (reply_hdr.size > 2) + dnbd3_drain_socket(dev, dev->sock, reply_hdr.size - 2); continue; case CMD_KEEPALIVE: - if (dnbd3_reply.size != 0) - printk("ERROR: keep alive packet with payload.\n"); + if (reply_hdr.size != 0) { + dev_dbg(dnbd3_device_to_dev(dev), "keep alive packet with payload\n"); + dnbd3_drain_socket(dev, dev->sock, reply_hdr.size); + } continue; default: - printk("ERROR: Unknown command (Receive)\n"); - continue; + dev_err(dnbd3_device_to_dev(dev), "unknown command: %d (receive), aborting connection\n", (int)reply_hdr.cmd); + goto out_unlock; + } + } +out_unlock: + // This will check if we actually still need a new connection + dnbd3_start_discover(dev, true); + mutex_unlock(&dev->recv_mutex); +} +/** + * Set send or receive timeout of given socket + */ +static void set_socket_timeout(struct socket *sock, bool set_send, int timeout_ms) +{ +#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 1, 0) + int opt = set_send ? SO_SNDTIMEO_NEW : SO_RCVTIMEO_NEW; + struct __kernel_sock_timeval timeout; +#else + int opt = set_send ? SO_SNDTIMEO : SO_RCVTIMEO; + struct timeval timeout; +#endif +#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 9, 0) + sockptr_t timeout_ptr = KERNEL_SOCKPTR(&timeout); +#else + char *timeout_ptr = (char *)&timeout; +#endif + + timeout.tv_sec = timeout_ms / 1000; + timeout.tv_usec = (timeout_ms % 1000) * 1000; + sock_setsockopt(sock, SOL_SOCKET, opt, timeout_ptr, sizeof(timeout)); +} + +static int dnbd3_connect(dnbd3_device_t *dev, struct sockaddr_storage *addr, struct socket **sock_out) +{ + ktime_t start; + int ret, connect_time_ms; + struct socket *sock; + int retries = 4; + const int addrlen = addr->ss_family == AF_INET ? sizeof(struct sockaddr_in) + : sizeof(struct sockaddr_in6); + +#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 2, 0) + ret = sock_create_kern(&init_net, addr->ss_family, SOCK_STREAM, + IPPROTO_TCP, &sock); +#else + ret = sock_create_kern(addr->ss_family, SOCK_STREAM, + IPPROTO_TCP, &sock); +#endif + if (ret < 0) { + dev_err(dnbd3_device_to_dev(dev), "couldn't create socket: %d\n", ret); + return ret; + } + + /* Only one retry, TCP no delay */ +#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 8, 0) + tcp_sock_set_syncnt(sock->sk, 1); + tcp_sock_set_nodelay(sock->sk); + /* because of our aggressive timeouts, this is pointless */ + sock_no_linger(sock->sk); +#else + /* add legacy version of this, but ignore others as they're not that important */ + ret = 1; + kernel_setsockopt(sock, IPPROTO_TCP, TCP_SYNCNT, + (char *)&ret, sizeof(ret)); +#endif + /* allow this socket to use reserved mem (vm.mem_free_kbytes) */ + sk_set_memalloc(sock->sk); + sock->sk->sk_allocation = GFP_NOIO; + + if (dev->panic && dev->panic_count > 1) { + /* in panic mode for some time, start increasing timeouts */ + connect_time_ms = dev->panic_count * 1000; + } else { + /* otherwise, use 2*RTT of current server */ + connect_time_ms = dev->cur_server.rtt * 2 / 1000; + } + /* but obey a minimal configurable value, and maximum sanity check */ + if (connect_time_ms < SOCKET_TIMEOUT_SEND * 1000) + connect_time_ms = SOCKET_TIMEOUT_SEND * 1000; + else if (connect_time_ms > 60000) + connect_time_ms = 60000; + set_socket_timeout(sock, false, connect_time_ms); // recv + set_socket_timeout(sock, true, connect_time_ms); // send + start = ktime_get_real(); + while (--retries > 0) { + ret = kernel_connect(sock, (struct sockaddr *)addr, addrlen, 0); + connect_time_ms = (int)ktime_ms_delta(ktime_get_real(), start); + if (connect_time_ms > 2 * SOCKET_TIMEOUT_SEND * 1000) { + /* Either I'm losing my mind or there was a specific build of kernel + * 5.x where SO_RCVTIMEO didn't affect the connect call above, so + * this function would hang for over a minute for unreachable hosts. + * Leave in this debug check for twice the configured timeout + */ + dnbd3_dev_dbg_host(dev, addr, "connect: call took %dms\n", + connect_time_ms); } + if (ret != 0) { + if (ret == -EINTR) + dnbd3_dev_dbg_host(dev, addr, "connect: interrupted system call (blocked %dms)\n", + connect_time_ms); + else + dnbd3_dev_dbg_host(dev, addr, "connect: failed (%d, blocked %dms)\n", + ret, connect_time_ms); + goto error; + } + *sock_out = sock; + return 0; } +error: + sock_release(sock); + return ret < 0 ? ret : -EIO; +} - printk("dnbd3_net_receive terminated normally.\n"); - dev->thread_receive = NULL; - return 0; +#define dnbd3_err_dbg_host(...) do { \ + if (dev->panic || dev->sock == NULL) \ + dnbd3_dev_err_host(__VA_ARGS__); \ + else \ + dnbd3_dev_dbg_host(__VA_ARGS__); \ +} while (0) + +/** + * Execute protocol handshake on a newly connected socket. + * If this is the initial connection to any server, ie. we're being called + * through the initial ioctl() to open a device, we'll store the rid, filesize + * etc. in the dev struct., otherwise, this is a potential switch to another + * server, so we validate the filesize, rid, name against what we expect. + * The server's protocol version is returned in 'remote_version' + */ +static bool dnbd3_execute_handshake(dnbd3_device_t *dev, struct socket *sock, + struct sockaddr_storage *addr, uint16_t *remote_version, bool copy_data) +{ + unsigned long irqflags; + const char *name; + uint64_t filesize; + int mlen; + uint16_t rid; + struct msghdr msg = { .msg_flags = MSG_NOSIGNAL | MSG_WAITALL }; + struct kvec iov[2]; + serialized_buffer_t *payload; + dnbd3_reply_t reply_hdr; + dnbd3_request_t request_hdr = { .magic = dnbd3_packet_magic }; + + payload = kmalloc(sizeof(*payload), GFP_KERNEL); + if (payload == NULL) + goto error; + + if (copy_data && device_active(dev)) + dev_warn(dnbd3_device_to_dev(dev), "Called handshake function with copy_data enabled when reported_size is not zero\n"); + + // Request filesize + request_hdr.cmd = CMD_SELECT_IMAGE; + iov[0].iov_base = &request_hdr; + iov[0].iov_len = sizeof(request_hdr); + serializer_reset_write(payload); + serializer_put_uint16(payload, PROTOCOL_VERSION); // DNBD3 protocol version + serializer_put_string(payload, dev->imgname); // image name + serializer_put_uint16(payload, dev->rid); // revision id + serializer_put_uint8(payload, 0); // are we a server? (no!) + iov[1].iov_base = payload; + request_hdr.size = iov[1].iov_len = serializer_get_written_length(payload); + fixup_request(request_hdr); + mlen = iov[0].iov_len + iov[1].iov_len; + if (kernel_sendmsg(sock, &msg, iov, 2, mlen) != mlen) { + dnbd3_err_dbg_host(dev, addr, "requesting image size failed\n"); + goto error; + } + + // receive net reply + if (dnbd3_recv_reply(sock, &reply_hdr) != sizeof(reply_hdr)) { + dnbd3_err_dbg_host(dev, addr, "receiving image size packet (header) failed\n"); + goto error; + } + if (reply_hdr.magic != dnbd3_packet_magic + || reply_hdr.cmd != CMD_SELECT_IMAGE || reply_hdr.size < 4 + || reply_hdr.size > sizeof(*payload)) { + dnbd3_err_dbg_host(dev, addr, + "corrupt CMD_SELECT_IMAGE reply\n"); + goto error; + } + + // receive data + iov[0].iov_base = payload; + iov[0].iov_len = reply_hdr.size; + if (kernel_recvmsg(sock, &msg, iov, 1, reply_hdr.size, msg.msg_flags) + != reply_hdr.size) { + dnbd3_err_dbg_host(dev, addr, + "receiving payload of CMD_SELECT_IMAGE reply failed\n"); + goto error; + } + serializer_reset_read(payload, reply_hdr.size); + + *remote_version = serializer_get_uint16(payload); + name = serializer_get_string(payload); + rid = serializer_get_uint16(payload); + filesize = serializer_get_uint64(payload); + + if (*remote_version < MIN_SUPPORTED_SERVER) { + dnbd3_err_dbg_host(dev, addr, + "server version too old (client: %d, server: %d, min supported: %d)\n", + (int)PROTOCOL_VERSION, (int)*remote_version, + (int)MIN_SUPPORTED_SERVER); + goto error; + } + if (name == NULL) { + dnbd3_err_dbg_host(dev, addr, "server did not supply an image name\n"); + goto error; + } + if (rid == 0) { + dnbd3_err_dbg_host(dev, addr, "server did not supply a revision id\n"); + goto error; + } + + if (copy_data) { + if (filesize < DNBD3_BLOCK_SIZE) { + dnbd3_err_dbg_host(dev, addr, "reported size by server is < 4096\n"); + goto error; + } + spin_lock_irqsave(&dev->blk_lock, irqflags); + if (strlen(dev->imgname) < strlen(name)) { + dev->imgname = krealloc(dev->imgname, strlen(name) + 1, GFP_KERNEL); + if (dev->imgname == NULL) { + spin_unlock_irqrestore(&dev->blk_lock, irqflags); + dnbd3_err_dbg_host(dev, addr, "reallocating buffer for new image name failed\n"); + goto error; + } + } + strcpy(dev->imgname, name); + dev->rid = rid; + // store image information + dev->reported_size = filesize; + dev->update_available = 0; + spin_unlock_irqrestore(&dev->blk_lock, irqflags); + set_capacity(dev->disk, dev->reported_size >> 9); /* 512 Byte blocks */ + dnbd3_dev_dbg_host(dev, addr, "image size: %llu\n", dev->reported_size); + } else { + /* switching connection, sanity checks */ + if (rid != dev->rid) { + dnbd3_err_dbg_host(dev, addr, + "server supplied wrong rid (client: '%d', server: '%d')\n", + (int)dev->rid, (int)rid); + goto error; + } + + if (strcmp(name, dev->imgname) != 0) { + dnbd3_err_dbg_host(dev, addr, "server offers image '%s', requested '%s'\n", name, dev->imgname); + goto error; + } + + if (filesize != dev->reported_size) { + dnbd3_err_dbg_host(dev, addr, + "reported image size of %llu does not match expected value %llu\n", + (unsigned long long)filesize, (unsigned long long)dev->reported_size); + goto error; + } + } + kfree(payload); + return true; + +error: + kfree(payload); + return false; +} + +static bool dnbd3_send_request(struct socket *sock, u16 cmd, u64 handle, u64 offset, u32 size) +{ + struct msghdr msg = { .msg_flags = MSG_NOSIGNAL }; + dnbd3_request_t request_hdr = { + .magic = dnbd3_packet_magic, + .cmd = cmd, + .size = size, + .offset = offset, + .handle = handle, + }; + struct kvec iov = { .iov_base = &request_hdr, .iov_len = sizeof(request_hdr) }; + + fixup_request(request_hdr); + return kernel_sendmsg(sock, &msg, &iov, 1, sizeof(request_hdr)) == sizeof(request_hdr); +} + +/** + * Send a request with given cmd type and empty payload. + */ +static bool dnbd3_send_empty_request(dnbd3_device_t *dev, u16 cmd) +{ + int ret; + + mutex_lock(&dev->send_mutex); + ret = dev->sock + && dnbd3_send_request(dev->sock, cmd, 0, 0, 0); + mutex_unlock(&dev->send_mutex); + return ret; +} + +static int dnbd3_recv_bytes(struct socket *sock, void *buffer, size_t count) +{ + struct msghdr msg = { .msg_flags = MSG_NOSIGNAL | MSG_WAITALL }; + struct kvec iov = { .iov_base = buffer, .iov_len = count }; + + return kernel_recvmsg(sock, &msg, &iov, 1, count, msg.msg_flags); +} + +static int dnbd3_recv_reply(struct socket *sock, dnbd3_reply_t *reply_hdr) +{ + int ret = dnbd3_recv_bytes(sock, reply_hdr, sizeof(*reply_hdr)); + + fixup_reply(*reply_hdr); + return ret; +} + +static bool dnbd3_drain_socket(dnbd3_device_t *dev, struct socket *sock, int bytes) +{ + int ret; + struct kvec iov; + struct msghdr msg = { .msg_flags = MSG_NOSIGNAL }; + + while (bytes > 0) { + iov.iov_base = __garbage_mem; + iov.iov_len = sizeof(__garbage_mem); + ret = kernel_recvmsg(sock, &msg, &iov, 1, MIN(bytes, iov.iov_len), msg.msg_flags); + if (ret <= 0) { + dnbd3_dev_err_cur(dev, "draining payload failed (ret=%d)\n", ret); + return false; + } + bytes -= ret; + } + return true; +} + +static bool dnbd3_request_test_block(dnbd3_device_t *dev, struct sockaddr_storage *addr, struct socket *sock) +{ + dnbd3_reply_t reply_hdr; + + // Request block + if (!dnbd3_send_request(sock, CMD_GET_BLOCK, 0, 0, RTT_BLOCK_SIZE)) { + dnbd3_err_dbg_host(dev, addr, "requesting test block failed\n"); + return false; + } + + // receive net reply + if (dnbd3_recv_reply(sock, &reply_hdr) != sizeof(reply_hdr)) { + dnbd3_err_dbg_host(dev, addr, "receiving test block header packet failed\n"); + return false; + } + if (reply_hdr.magic != dnbd3_packet_magic || reply_hdr.cmd != CMD_GET_BLOCK + || reply_hdr.size != RTT_BLOCK_SIZE || reply_hdr.handle != 0) { + dnbd3_err_dbg_host(dev, addr, + "unexpected reply to block request: cmd=%d, size=%d, handle=%llu (discover)\n", + (int)reply_hdr.cmd, (int)reply_hdr.size, reply_hdr.handle); + return false; + } - error: + // receive data + return dnbd3_drain_socket(dev, sock, RTT_BLOCK_SIZE); +} +#undef dnbd3_err_dbg_host + +static void replace_main_socket(dnbd3_device_t *dev, struct socket *sock, struct sockaddr_storage *addr, u16 protocol_version) +{ + unsigned long irqflags; + + mutex_lock(&dev->send_mutex); + // First, shutdown connection, so receive worker will leave its mainloop if (dev->sock) kernel_sock_shutdown(dev->sock, SHUT_RDWR); - if (!dev->disconnecting) - { - dev->panic = 1; - dev->discover = 1; - wake_up(&dev->process_queue_discover); + mutex_lock(&dev->recv_mutex); + // Receive worker is done, get rid of socket and replace + if (dev->sock) + sock_release(dev->sock); + dev->sock = sock; + spin_lock_irqsave(&dev->blk_lock, irqflags); + if (addr == NULL) { + memset(&dev->cur_server, 0, sizeof(dev->cur_server)); + } else { + dev->cur_server.host = *addr; + dev->cur_server.rtt = 0; + dev->cur_server.protocol_version = protocol_version; } - dev->thread_receive = NULL; - return -1; + spin_unlock_irqrestore(&dev->blk_lock, irqflags); + mutex_unlock(&dev->recv_mutex); + mutex_unlock(&dev->send_mutex); } +static void dnbd3_release_resources(dnbd3_device_t *dev) +{ + if (dev->send_wq) + destroy_workqueue(dev->send_wq); + dev->send_wq = NULL; + if (dev->recv_wq) + destroy_workqueue(dev->recv_wq); + dev->recv_wq = NULL; + mutex_destroy(&dev->send_mutex); + mutex_destroy(&dev->recv_mutex); +} + +/** + * Establish new connection on a dnbd3 device. + * Return 0 on success, errno otherwise + */ +int dnbd3_new_connection(dnbd3_device_t *dev, struct sockaddr_storage *addr, bool init) +{ + unsigned long irqflags; + struct socket *sock = NULL; + uint16_t proto_version; + int ret; + + ASSERT(dnbd3_flag_taken(dev->connection_lock)); + if (init && device_active(dev)) { + dnbd3_dev_err_cur(dev, "device already configured/connected\n"); + return -EBUSY; + } + if (!init && !device_active(dev)) { + dev_warn(dnbd3_device_to_dev(dev), "connection switch called on unconfigured device\n"); + return -ENOTCONN; + } + + dnbd3_dev_dbg_host(dev, addr, "connecting...\n"); + ret = dnbd3_connect(dev, addr, &sock); + if (ret != 0 || sock == NULL) + goto error; + + /* execute the "select image" handshake */ + // if init is true, reported_size will be set + if (!dnbd3_execute_handshake(dev, sock, addr, &proto_version, init)) { + ret = -EINVAL; + goto error; + } + + if (init) { + // We're setting up the device for use - allocate resources + // Do not goto error before this + ASSERT(!dev->send_wq); + ASSERT(!dev->recv_wq); + mutex_init(&dev->send_mutex); + mutex_init(&dev->recv_mutex); + // a designated queue for sending, that allows one active task only + dev->send_wq = alloc_workqueue("dnbd%d-send", + WQ_UNBOUND | WQ_FREEZABLE | WQ_MEM_RECLAIM | WQ_HIGHPRI, + 1, dev->index); + dev->recv_wq = alloc_workqueue("dnbd%d-recv", + WQ_UNBOUND | WQ_FREEZABLE | WQ_MEM_RECLAIM | WQ_HIGHPRI | WQ_CPU_INTENSIVE, + 1, dev->index); + if (!dev->send_wq || !dev->recv_wq) { + ret = -ENOMEM; + goto error_dealloc; + } + } + + set_socket_timeout(sock, false, SOCKET_TIMEOUT_RECV * 1000); // recv + dnbd3_set_primary_connection(dev, sock, addr, proto_version); + sock = NULL; // In case we ever goto error* after this point + + spin_lock_irqsave(&dev->blk_lock, irqflags); + if (init) { + dev->discover_count = 0; + dev->discover_interval = TIMER_INTERVAL_PROBE_STARTUP; + // discovery and keepalive are not critical, use the power efficient queue + queue_delayed_work(system_power_efficient_wq, &dev->discover_work, + dev->discover_interval * HZ); + queue_delayed_work(system_power_efficient_wq, &dev->keepalive_work, + KEEPALIVE_INTERVAL * HZ); + // but the receiver is performance critical AND runs indefinitely, use the + // the cpu intensive queue, as jobs submitted there will not cound towards + // the concurrency limit of per-cpu worker threads. It still feels a little + // dirty to avoid managing our own thread, but nbd does it too. + } + spin_unlock_irqrestore(&dev->blk_lock, irqflags); + return 0; + +error_dealloc: + if (init) { + // If anything fails during initialization, free resources again + dnbd3_release_resources(dev); + } +error: + if (init) + dev->reported_size = 0; + if (sock) + sock_release(sock); + return ret < 0 ? ret : -EIO; +} + +void dnbd3_net_work_init(dnbd3_device_t *dev) +{ + INIT_WORK(&dev->send_work, dnbd3_send_workfn); + INIT_WORK(&dev->recv_work, dnbd3_recv_workfn); + INIT_DELAYED_WORK(&dev->discover_work, dnbd3_discover_workfn); + INIT_DELAYED_WORK(&dev->keepalive_work, dnbd3_keepalive_workfn); +} + +static int dnbd3_set_primary_connection(dnbd3_device_t *dev, struct socket *sock, struct sockaddr_storage *addr, u16 protocol_version) +{ + unsigned long irqflags; + + ASSERT(dnbd3_flag_taken(dev->connection_lock)); + if (addr->ss_family == 0 || dev->imgname == NULL || sock == NULL) { + dnbd3_dev_err_cur(dev, "connect: host, image name or sock not set\n"); + return -EINVAL; + } + + replace_main_socket(dev, sock, addr, protocol_version); + spin_lock_irqsave(&dev->blk_lock, irqflags); + dev->panic = false; + dev->panic_count = 0; + dev->discover_interval = TIMER_INTERVAL_PROBE_SWITCH; + queue_work(dev->recv_wq, &dev->recv_work); + spin_unlock_irqrestore(&dev->blk_lock, irqflags); + + if (dev->use_server_provided_alts) + dnbd3_send_empty_request(dev, CMD_GET_SERVERS); + + dnbd3_dev_info_cur(dev, "connection switched\n"); + dnbd3_blk_requeue_all_requests(dev); + return 0; +} + +/** + * Disconnect the device, shutting it down. + */ +int dnbd3_net_disconnect(dnbd3_device_t *dev) +{ + ASSERT(dnbd3_flag_taken(dev->connection_lock)); + if (!device_active(dev)) + return -ENOTCONN; + dev_dbg(dnbd3_device_to_dev(dev), "disconnecting device ...\n"); + + dev->reported_size = 0; + /* quickly fail all requests */ + dnbd3_blk_fail_all_requests(dev); + replace_main_socket(dev, NULL, NULL, 0); + + cancel_delayed_work_sync(&dev->keepalive_work); + cancel_delayed_work_sync(&dev->discover_work); + cancel_work_sync(&dev->send_work); + cancel_work_sync(&dev->recv_work); + + dnbd3_blk_fail_all_requests(dev); + dnbd3_release_resources(dev); + dev_dbg(dnbd3_device_to_dev(dev), "all workers shut down\n"); + return 0; +} |