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Diffstat (limited to 'src/libcharon/plugins/kernel_netlink/kernel_netlink_shared.c')
-rw-r--r--src/libcharon/plugins/kernel_netlink/kernel_netlink_shared.c655
1 files changed, 655 insertions, 0 deletions
diff --git a/src/libcharon/plugins/kernel_netlink/kernel_netlink_shared.c b/src/libcharon/plugins/kernel_netlink/kernel_netlink_shared.c
new file mode 100644
index 000000000..f7ce992a3
--- /dev/null
+++ b/src/libcharon/plugins/kernel_netlink/kernel_netlink_shared.c
@@ -0,0 +1,655 @@
+/*
+ * Copyright (C) 2014 Martin Willi
+ * Copyright (C) 2014 revosec AG
+ * Copyright (C) 2008 Tobias Brunner
+ * Hochschule fuer Technik Rapperswil
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * for more details.
+ */
+
+#include <sys/socket.h>
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
+#include <linux/xfrm.h>
+#include <errno.h>
+#include <unistd.h>
+
+#include "kernel_netlink_shared.h"
+
+#include <utils/debug.h>
+#include <threading/mutex.h>
+#include <threading/condvar.h>
+#include <collections/array.h>
+#include <collections/hashtable.h>
+
+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 entries
+ */
+ mutex_t *mutex;
+
+ /**
+ * Netlink request entries currently active, uintptr_t seq => entry_t
+ */
+ hashtable_t *entries;
+
+ /**
+ * Current sequence number for Netlink requests
+ */
+ refcount_t seq;
+
+ /**
+ * netlink socket
+ */
+ int socket;
+
+ /**
+ * Netlink protocol
+ */
+ int protocol;
+
+ /**
+ * Enum names for Netlink messages
+ */
+ enum_name_t *names;
+
+ /**
+ * Timeout for Netlink replies, in ms
+ */
+ u_int timeout;
+
+ /**
+ * Number of times to repeat timed out queries
+ */
+ u_int retries;
+
+ /**
+ * Buffer size for received Netlink messages
+ */
+ u_int buflen;
+
+ /**
+ * Use parallel netlink queries
+ */
+ bool parallel;
+
+ /**
+ * Ignore errors potentially resulting from a retransmission
+ */
+ bool ignore_retransmit_errors;
+};
+
+/**
+ * #definable hook to simulate request message loss
+ */
+#ifdef NETLINK_MSG_LOSS_HOOK
+bool NETLINK_MSG_LOSS_HOOK(struct nlmsghdr *msg);
+#define msg_loss_hook(msg) NETLINK_MSG_LOSS_HOOK(msg)
+#else
+#define msg_loss_hook(msg) FALSE
+#endif
+
+/**
+ * Request entry the answer for a waiting thread is collected in
+ */
+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;
+
+ if (msg_loss_hook(msg))
+ {
+ return TRUE;
+ }
+
+ 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, return 0 on error, -1 on timeout
+ */
+static ssize_t read_msg(private_netlink_socket_t *this,
+ char *buf, size_t buflen, bool block)
+{
+ ssize_t len;
+
+ if (block)
+ {
+ fd_set set;
+ timeval_t tv = {};
+
+ FD_ZERO(&set);
+ FD_SET(this->socket, &set);
+ timeval_add_ms(&tv, this->timeout);
+
+ if (select(this->socket + 1, &set, NULL, NULL,
+ this->timeout ? &tv : NULL) <= 0)
+ {
+ return -1;
+ }
+ }
+ len = recv(this->socket, buf, buflen, MSG_TRUNC|(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, returns TRUE on timeout
+ */
+static bool read_and_queue(private_netlink_socket_t *this, bool block)
+{
+ struct nlmsghdr *hdr;
+ char buf[this->buflen];
+ ssize_t len;
+
+ len = read_msg(this, buf, sizeof(buf), block);
+ if (len == -1)
+ {
+ return TRUE;
+ }
+ if (len)
+ {
+ hdr = (struct nlmsghdr*)buf;
+ while (NLMSG_OK(hdr, len))
+ {
+ if (!queue(this, hdr))
+ {
+ break;
+ }
+ hdr = NLMSG_NEXT(hdr, len);
+ }
+ }
+ return FALSE;
+}
+
+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;
+}
+
+/**
+ * Send a netlink request, try once
+ */
+static status_t send_once(private_netlink_socket_t *this, struct nlmsghdr *in,
+ uintptr_t seq, struct nlmsghdr **out, size_t *out_len)
+{
+ struct nlmsghdr *hdr;
+ chunk_t result = {};
+ entry_t *entry;
+
+ in->nlmsg_seq = seq;
+ in->nlmsg_pid = getpid();
+
+ if (this->names)
+ {
+ DBG3(DBG_KNL, "sending %N %u: %b", this->names, in->nlmsg_type,
+ (u_int)seq, in, in->nlmsg_len);
+ }
+
+ this->mutex->lock(this->mutex);
+ if (!write_msg(this, in))
+ {
+ this->mutex->unlock(this->mutex);
+ return FAILED;
+ }
+
+ INIT(entry,
+ .condvar = condvar_create(CONDVAR_TYPE_DEFAULT),
+ .hdrs = array_create(0, 0),
+ );
+ this->entries->put(this->entries, (void*)seq, entry);
+
+ while (!entry->complete)
+ {
+ if (this->parallel &&
+ lib->watcher->get_state(lib->watcher) == WATCHER_RUNNING)
+ {
+ if (this->timeout)
+ {
+ if (entry->condvar->timed_wait(entry->condvar, this->mutex,
+ this->timeout))
+ {
+ break;
+ }
+ }
+ else
+ {
+ entry->condvar->wait(entry->condvar, this->mutex);
+ }
+ }
+ else
+ { /* During (de-)initialization, no watcher thread is active.
+ * collect responses ourselves. */
+ if (read_and_queue(this, TRUE))
+ {
+ break;
+ }
+ }
+ }
+ this->entries->remove(this->entries, (void*)seq);
+
+ this->mutex->unlock(this->mutex);
+
+ if (!entry->complete)
+ { /* timeout */
+ destroy_entry(entry);
+ return OUT_OF_RES;
+ }
+
+ 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;
+
+ return SUCCESS;
+}
+
+/**
+ * Ignore errors for message types that might have completed previously
+ */
+static void ignore_retransmit_error(private_netlink_socket_t *this,
+ struct nlmsgerr *err, int type)
+{
+ switch (err->error)
+ {
+ case -EEXIST:
+ switch (this->protocol)
+ {
+ case NETLINK_XFRM:
+ switch (type)
+ {
+ case XFRM_MSG_NEWPOLICY:
+ case XFRM_MSG_NEWSA:
+ err->error = 0;
+ break;
+ }
+ break;
+ case NETLINK_ROUTE:
+ switch (type)
+ {
+ case RTM_NEWADDR:
+ case RTM_NEWLINK:
+ case RTM_NEWNEIGH:
+ case RTM_NEWROUTE:
+ case RTM_NEWRULE:
+ err->error = 0;
+ break;
+ }
+ break;
+ }
+ break;
+ case -ENOENT:
+ switch (this->protocol)
+ {
+ case NETLINK_XFRM:
+ switch (type)
+ {
+ case XFRM_MSG_DELPOLICY:
+ case XFRM_MSG_DELSA:
+ err->error = 0;
+ break;
+ }
+ break;
+ case NETLINK_ROUTE:
+ switch (type)
+ {
+ case RTM_DELADDR:
+ case RTM_DELLINK:
+ case RTM_DELNEIGH:
+ case RTM_DELROUTE:
+ case RTM_DELRULE:
+ err->error = 0;
+ break;
+ }
+ break;
+ }
+ break;
+ }
+}
+
+METHOD(netlink_socket_t, netlink_send, status_t,
+ private_netlink_socket_t *this, struct nlmsghdr *in, struct nlmsghdr **out,
+ size_t *out_len)
+{
+ uintptr_t seq;
+ u_int try;
+
+ seq = ref_get(&this->seq);
+
+ for (try = 0; try <= this->retries; ++try)
+ {
+ struct nlmsghdr *hdr;
+ status_t status;
+ size_t len;
+
+ if (try > 0)
+ {
+ DBG1(DBG_KNL, "retransmitting Netlink request (%u/%u)",
+ try, this->retries);
+ }
+ status = send_once(this, in, seq, &hdr, &len);
+ switch (status)
+ {
+ case SUCCESS:
+ break;
+ case OUT_OF_RES:
+ continue;
+ default:
+ return status;
+ }
+ if (hdr->nlmsg_type == NLMSG_ERROR)
+ {
+ struct nlmsgerr* err;
+
+ err = NLMSG_DATA(hdr);
+ if (err->error == -EBUSY)
+ {
+ free(hdr);
+ try--;
+ continue;
+ }
+ if (this->ignore_retransmit_errors && try > 0)
+ {
+ ignore_retransmit_error(this, err, in->nlmsg_type);
+ }
+ }
+ *out = hdr;
+ *out_len = len;
+ return SUCCESS;
+ }
+ DBG1(DBG_KNL, "Netlink request timed out after %u retransmits",
+ this->retries);
+ return OUT_OF_RES;
+}
+
+METHOD(netlink_socket_t, netlink_send_ack, status_t,
+ private_netlink_socket_t *this, struct nlmsghdr *in)
+{
+ struct nlmsghdr *out, *hdr;
+ size_t len;
+
+ if (netlink_send(this, in, &out, &len) != SUCCESS)
+ {
+ return FAILED;
+ }
+ hdr = out;
+ while (NLMSG_OK(hdr, len))
+ {
+ switch (hdr->nlmsg_type)
+ {
+ case NLMSG_ERROR:
+ {
+ struct nlmsgerr* err = NLMSG_DATA(hdr);
+
+ if (err->error)
+ {
+ if (-err->error == EEXIST)
+ { /* do not report existing routes */
+ free(out);
+ return ALREADY_DONE;
+ }
+ if (-err->error == ESRCH)
+ { /* do not report missing entries */
+ free(out);
+ return NOT_FOUND;
+ }
+ DBG1(DBG_KNL, "received netlink error: %s (%d)",
+ strerror(-err->error), -err->error);
+ free(out);
+ return FAILED;
+ }
+ free(out);
+ return SUCCESS;
+ }
+ default:
+ hdr = NLMSG_NEXT(hdr, len);
+ continue;
+ case NLMSG_DONE:
+ break;
+ }
+ break;
+ }
+ DBG1(DBG_KNL, "netlink request not acknowledged");
+ free(out);
+ return FAILED;
+}
+
+METHOD(netlink_socket_t, destroy, void,
+ private_netlink_socket_t *this)
+{
+ if (this->socket != -1)
+ {
+ if (this->parallel)
+ {
+ lib->watcher->remove(lib->watcher, this->socket);
+ }
+ close(this->socket);
+ }
+ this->entries->destroy(this->entries);
+ this->mutex->destroy(this->mutex);
+ free(this);
+}
+
+/**
+ * Described in header.
+ */
+netlink_socket_t *netlink_socket_create(int protocol, enum_name_t *names,
+ bool parallel)
+{
+ private_netlink_socket_t *this;
+ struct sockaddr_nl addr = {
+ .nl_family = AF_NETLINK,
+ };
+
+ INIT(this,
+ .public = {
+ .send = _netlink_send,
+ .send_ack = _netlink_send_ack,
+ .destroy = _destroy,
+ },
+ .seq = 200,
+ .mutex = mutex_create(MUTEX_TYPE_RECURSIVE),
+ .socket = socket(AF_NETLINK, SOCK_RAW, protocol),
+ .entries = hashtable_create(hashtable_hash_ptr, hashtable_equals_ptr, 4),
+ .protocol = protocol,
+ .names = names,
+ .buflen = lib->settings->get_int(lib->settings,
+ "%s.plugins.kernel-netlink.buflen", 0, lib->ns),
+ .timeout = lib->settings->get_int(lib->settings,
+ "%s.plugins.kernel-netlink.timeout", 0, lib->ns),
+ .retries = lib->settings->get_int(lib->settings,
+ "%s.plugins.kernel-netlink.retries", 0, lib->ns),
+ .ignore_retransmit_errors = lib->settings->get_bool(lib->settings,
+ "%s.plugins.kernel-netlink.ignore_retransmit_errors",
+ FALSE, lib->ns),
+ .parallel = parallel,
+ );
+
+ if (!this->buflen)
+ {
+ long pagesize = sysconf(_SC_PAGESIZE);
+ if (pagesize == -1)
+ {
+ pagesize = 4096;
+ }
+ /* base this on NLMSG_GOODSIZE */
+ this->buflen = min(pagesize, 8192);
+ }
+ if (this->socket == -1)
+ {
+ DBG1(DBG_KNL, "unable to create netlink socket");
+ destroy(this);
+ return NULL;
+ }
+ if (bind(this->socket, (struct sockaddr*)&addr, sizeof(addr)))
+ {
+ DBG1(DBG_KNL, "unable to bind netlink socket");
+ destroy(this);
+ return NULL;
+ }
+ if (this->parallel)
+ {
+ lib->watcher->add(lib->watcher, this->socket, WATCHER_READ, watch, this);
+ }
+
+ return &this->public;
+}
+
+/**
+ * Described in header.
+ */
+void netlink_add_attribute(struct nlmsghdr *hdr, int rta_type, chunk_t data,
+ size_t buflen)
+{
+ struct rtattr *rta;
+
+ if (NLMSG_ALIGN(hdr->nlmsg_len) + RTA_LENGTH(data.len) > buflen)
+ {
+ DBG1(DBG_KNL, "unable to add attribute, buffer too small");
+ return;
+ }
+
+ rta = (struct rtattr*)(((char*)hdr) + NLMSG_ALIGN(hdr->nlmsg_len));
+ rta->rta_type = rta_type;
+ rta->rta_len = RTA_LENGTH(data.len);
+ memcpy(RTA_DATA(rta), data.ptr, data.len);
+ hdr->nlmsg_len = NLMSG_ALIGN(hdr->nlmsg_len) + rta->rta_len;
+}
+
+/**
+ * Described in header.
+ */
+void* netlink_reserve(struct nlmsghdr *hdr, int buflen, int type, int len)
+{
+ struct rtattr *rta;
+
+ if (NLMSG_ALIGN(hdr->nlmsg_len) + RTA_LENGTH(len) > buflen)
+ {
+ DBG1(DBG_KNL, "unable to add attribute, buffer too small");
+ return NULL;
+ }
+
+ rta = ((void*)hdr) + NLMSG_ALIGN(hdr->nlmsg_len);
+ rta->rta_type = type;
+ rta->rta_len = RTA_LENGTH(len);
+ hdr->nlmsg_len = NLMSG_ALIGN(hdr->nlmsg_len) + rta->rta_len;
+
+ return RTA_DATA(rta);
+}
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