diff --git a/src/libhydra/plugins/kernel_netlink/kernel_netlink_shared.c b/src/libhydra/plugins/kernel_netlink/kernel_netlink_shared.c index b4cece720..6e1dd8cf0 100644 --- a/src/libhydra/plugins/kernel_netlink/kernel_netlink_shared.c +++ b/src/libhydra/plugins/kernel_netlink/kernel_netlink_shared.c @@ -1,4 +1,6 @@ /* + * Copyright (C) 2014 Martin Willi + * Copyright (C) 2014 revosec AG * Copyright (C) 2008 Tobias Brunner * Hochschule fuer Technik Rapperswil * @@ -23,6 +25,9 @@ #include #include +#include +#include +#include typedef struct private_netlink_socket_t private_netlink_socket_t; @@ -30,20 +35,26 @@ typedef struct private_netlink_socket_t private_netlink_socket_t; * Private variables and functions of netlink_socket_t class. */ struct private_netlink_socket_t { + /** * public part of the netlink_socket_t object. */ netlink_socket_t public; /** - * mutex to lock access to netlink socket + * mutex to lock access entries */ mutex_t *mutex; /** - * current sequence number for netlink request + * Netlink request entries currently active, uintptr_t seq => entry_t */ - int seq; + hashtable_t *entries; + + /** + * Current sequence number for Netlink requests + */ + refcount_t seq; /** * netlink socket @@ -57,110 +68,212 @@ struct private_netlink_socket_t { }; /** - * Imported from kernel_netlink_ipsec.c + * Request entry the answer for a waiting thread is collected in */ -extern enum_name_t *xfrm_msg_names; +typedef struct { + /** Condition variable thread is waiting */ + condvar_t *condvar; + /** Array of hdrs in a multi-message response, as struct nlmsghdr* */ + array_t *hdrs; + /** All response messages received? */ + bool complete; +} entry_t; + +/** + * Clean up a thread waiting entry + */ +static void destroy_entry(entry_t *entry) +{ + entry->condvar->destroy(entry->condvar); + array_destroy_function(entry->hdrs, (void*)free, NULL); + free(entry); +} + +/** + * Write a Netlink message to socket + */ +static bool write_msg(private_netlink_socket_t *this, struct nlmsghdr *msg) +{ + struct sockaddr_nl addr = { + .nl_family = AF_NETLINK, + }; + int len; + + while (TRUE) + { + len = sendto(this->socket, msg, msg->nlmsg_len, 0, + (struct sockaddr*)&addr, sizeof(addr)); + if (len != msg->nlmsg_len) + { + if (errno == EINTR) + { + continue; + } + DBG1(DBG_KNL, "netlink write error: %s", strerror(errno)); + return FALSE; + } + return TRUE; + } +} + +/** + * Read a single Netlink message from socket + */ +static size_t read_msg(private_netlink_socket_t *this, + char buf[4096], size_t buflen, bool block) +{ + ssize_t len; + + len = recv(this->socket, buf, buflen, block ? 0 : MSG_DONTWAIT); + if (len == buflen) + { + DBG1(DBG_KNL, "netlink response exceeds buffer size"); + return 0; + } + if (len < 0) + { + if (errno != EAGAIN && errno != EWOULDBLOCK && errno != EINTR) + { + DBG1(DBG_KNL, "netlink read error: %s", strerror(errno)); + } + return 0; + } + return len; +} + +/** + * Queue received response message + */ +static bool queue(private_netlink_socket_t *this, struct nlmsghdr *buf) +{ + struct nlmsghdr *hdr; + entry_t *entry; + uintptr_t seq; + + seq = (uintptr_t)buf->nlmsg_seq; + + this->mutex->lock(this->mutex); + entry = this->entries->get(this->entries, (void*)seq); + if (entry) + { + hdr = malloc(buf->nlmsg_len); + memcpy(hdr, buf, buf->nlmsg_len); + array_insert(entry->hdrs, ARRAY_TAIL, hdr); + if (hdr->nlmsg_type == NLMSG_DONE || !(hdr->nlmsg_flags & NLM_F_MULTI)) + { + entry->complete = TRUE; + entry->condvar->signal(entry->condvar); + } + } + else + { + DBG1(DBG_KNL, "received unknown netlink seq %u, ignored", seq); + } + this->mutex->unlock(this->mutex); + + return entry != NULL; +} + +/** + * Read and queue response message, optionally blocking + */ +static void read_and_queue(private_netlink_socket_t *this, bool block) +{ + struct nlmsghdr *hdr; + union { + struct nlmsghdr hdr; + char bytes[4096]; + } buf; + size_t len; + + len = read_msg(this, buf.bytes, sizeof(buf.bytes), block); + if (len) + { + hdr = &buf.hdr; + while (NLMSG_OK(hdr, len)) + { + if (!queue(this, hdr)) + { + break; + } + hdr = NLMSG_NEXT(hdr, len); + } + } +} + +CALLBACK(watch, bool, + private_netlink_socket_t *this, int fd, watcher_event_t event) +{ + if (event == WATCHER_READ) + { + read_and_queue(this, FALSE); + } + return TRUE; +} METHOD(netlink_socket_t, netlink_send, status_t, private_netlink_socket_t *this, struct nlmsghdr *in, struct nlmsghdr **out, size_t *out_len) { - union { - struct nlmsghdr hdr; - u_char bytes[4096]; - } response; - struct sockaddr_nl addr; - chunk_t result = chunk_empty; - int len; + struct nlmsghdr *hdr; + chunk_t result = {}; + entry_t *entry; + uintptr_t seq; - this->mutex->lock(this->mutex); - - in->nlmsg_seq = ++this->seq; + seq = ref_get(&this->seq); + in->nlmsg_seq = seq; in->nlmsg_pid = getpid(); - memset(&addr, 0, sizeof(addr)); - addr.nl_family = AF_NETLINK; - addr.nl_pid = 0; - addr.nl_groups = 0; - if (this->names) { - DBG3(DBG_KNL, "sending %N: %b", - this->names, in->nlmsg_type, in, in->nlmsg_len); + DBG3(DBG_KNL, "sending %N %u: %b", this->names, in->nlmsg_type, + (u_int)seq, in, in->nlmsg_len); } - while (TRUE) + + this->mutex->lock(this->mutex); + if (!write_msg(this, in)) { - len = sendto(this->socket, in, in->nlmsg_len, 0, - (struct sockaddr*)&addr, sizeof(addr)); - - if (len != in->nlmsg_len) - { - if (errno == EINTR) - { - /* interrupted, try again */ - continue; - } - this->mutex->unlock(this->mutex); - DBG1(DBG_KNL, "error sending to netlink socket: %s", strerror(errno)); - return FAILED; - } - break; + this->mutex->unlock(this->mutex); + return FAILED; } - while (TRUE) + INIT(entry, + .condvar = condvar_create(CONDVAR_TYPE_DEFAULT), + .hdrs = array_create(0, 0), + ); + this->entries->put(this->entries, (void*)seq, entry); + + while (!entry->complete) { - len = recv(this->socket, &response, sizeof(response), 0); - if (len < 0) + if (lib->watcher->get_state(lib->watcher) == WATCHER_RUNNING) { - if (errno == EINTR) - { - DBG1(DBG_KNL, "got interrupted"); - /* interrupted, try again */ - continue; - } - DBG1(DBG_KNL, "error reading from netlink socket: %s", strerror(errno)); - this->mutex->unlock(this->mutex); - free(result.ptr); - return FAILED; + entry->condvar->wait(entry->condvar, this->mutex); } - if (!NLMSG_OK(&response.hdr, len)) - { - DBG1(DBG_KNL, "received corrupted netlink message"); - this->mutex->unlock(this->mutex); - free(result.ptr); - return FAILED; + else + { /* During (de-)initialization, no watcher thread is active. + * collect responses ourselves. */ + read_and_queue(this, TRUE); } - if (response.hdr.nlmsg_seq != this->seq) - { - DBG1(DBG_KNL, "received invalid netlink sequence number"); - if (response.hdr.nlmsg_seq < this->seq) - { - continue; - } - this->mutex->unlock(this->mutex); - free(result.ptr); - return FAILED; - } - - result = chunk_cat("mc", result, chunk_create(response.bytes, len)); - - /* NLM_F_MULTI flag does not seem to be set correctly, we use sequence - * numbers to detect multi header messages */ - len = recv(this->socket, &response.hdr, sizeof(response.hdr), - MSG_PEEK | MSG_DONTWAIT); - if (len == sizeof(response.hdr) && response.hdr.nlmsg_seq == this->seq) - { - /* seems to be multipart */ - continue; - } - break; } + this->entries->remove(this->entries, (void*)seq); + + this->mutex->unlock(this->mutex); + + while (array_remove(entry->hdrs, ARRAY_HEAD, &hdr)) + { + if (this->names) + { + DBG3(DBG_KNL, "received %N %u: %b", this->names, hdr->nlmsg_type, + hdr->nlmsg_seq, hdr, hdr->nlmsg_len); + } + result = chunk_cat("mm", result, + chunk_create((char*)hdr, hdr->nlmsg_len)); + } + destroy_entry(entry); *out_len = result.len; *out = (struct nlmsghdr*)result.ptr; - this->mutex->unlock(this->mutex); - return SUCCESS; } @@ -221,8 +334,10 @@ METHOD(netlink_socket_t, destroy, void, { if (this->socket != -1) { + lib->watcher->remove(lib->watcher, this->socket); close(this->socket); } + this->entries->destroy(this->entries); this->mutex->destroy(this->mutex); free(this); } @@ -244,8 +359,9 @@ netlink_socket_t *netlink_socket_create(int protocol, enum_name_t *names) .destroy = _destroy, }, .seq = 200, - .mutex = mutex_create(MUTEX_TYPE_DEFAULT), + .mutex = mutex_create(MUTEX_TYPE_RECURSIVE), .socket = socket(AF_NETLINK, SOCK_RAW, protocol), + .entries = hashtable_create(hashtable_hash_ptr, hashtable_equals_ptr, 4), .names = names, ); @@ -262,6 +378,8 @@ netlink_socket_t *netlink_socket_create(int protocol, enum_name_t *names) return NULL; } + lib->watcher->add(lib->watcher, this->socket, WATCHER_READ, watch, this); + return &this->public; }