/***
This file is part of systemd.
Copyright 2013 Tom Gundersen <teg@jklm.no>
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <netinet/in.h>
#include <stdbool.h>
#include <unistd.h>
#include "sd-netlink.h"
#include "alloc-util.h"
#include "formats-util.h"
#include "missing.h"
#include "netlink-internal.h"
#include "netlink-types.h"
#include "netlink-util.h"
#include "refcnt.h"
#include "socket-util.h"
#include "util.h"
int socket_open(int family) {
int fd;
fd = socket(PF_NETLINK, SOCK_RAW|SOCK_CLOEXEC|SOCK_NONBLOCK, family);
if (fd < 0)
return -errno;
return fd;
}
static int broadcast_groups_get(sd_netlink *nl) {
_cleanup_free_ uint32_t *groups = NULL;
socklen_t len = 0, old_len;
unsigned i, j;
int r;
assert(nl);
assert(nl->fd >= 0);
r = getsockopt(nl->fd, SOL_NETLINK, NETLINK_LIST_MEMBERSHIPS, NULL, &len);
if (r < 0) {
if (errno == ENOPROTOOPT) {
nl->broadcast_group_dont_leave = true;
return 0;
} else
return -errno;
}
if (len == 0)
return 0;
groups = new0(uint32_t, len);
if (!groups)
return -ENOMEM;
old_len = len;
r = getsockopt(nl->fd, SOL_NETLINK, NETLINK_LIST_MEMBERSHIPS, groups, &len);
if (r < 0)
return -errno;
if (old_len != len)
return -EIO;
r = hashmap_ensure_allocated(&nl->broadcast_group_refs, NULL);
if (r < 0)
return r;
for (i = 0; i < len; i++) {
for (j = 0; j < sizeof(uint32_t) * 8; j ++) {
uint32_t offset;
unsigned group;
offset = 1U << j;
if (!(groups[i] & offset))
continue;
group = i * sizeof(uint32_t) * 8 + j + 1;
r = hashmap_put(nl->broadcast_group_refs, UINT_TO_PTR(group), UINT_TO_PTR(1));
if (r < 0)
return r;
}
}
return 0;
}
int socket_bind(sd_netlink *nl) {
socklen_t addrlen;
int r, one = 1;
r = setsockopt(nl->fd, SOL_NETLINK, NETLINK_PKTINFO, &one, sizeof(one));
if (r < 0)
return -errno;
addrlen = sizeof(nl->sockaddr);
r = bind(nl->fd, &nl->sockaddr.sa, addrlen);
/* ignore EINVAL to allow opening an already bound socket */
if (r < 0 && errno != EINVAL)
return -errno;
r = getsockname(nl->fd, &nl->sockaddr.sa, &addrlen);
if (r < 0)
return -errno;
r = broadcast_groups_get(nl);
if (r < 0)
return r;
return 0;
}
static unsigned broadcast_group_get_ref(sd_netlink *nl, unsigned group) {
assert(nl);
return PTR_TO_UINT(hashmap_get(nl->broadcast_group_refs, UINT_TO_PTR(group)));
}
static int broadcast_group_set_ref(sd_netlink *nl, unsigned group, unsigned n_ref) {
int r;
assert(nl);
r = hashmap_replace(nl->broadcast_group_refs, UINT_TO_PTR(group), UINT_TO_PTR(n_ref));
if (r < 0)
return r;
return 0;
}
static int broadcast_group_join(sd_netlink *nl, unsigned group) {
int r;
assert(nl);
assert(nl->fd >= 0);
assert(group > 0);
r = setsockopt(nl->fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &group, sizeof(group));
if (r < 0)
return -errno;
return 0;
}
int socket_broadcast_group_ref(sd_netlink *nl, unsigned group) {
unsigned n_ref;
int r;
assert(nl);
n_ref = broadcast_group_get_ref(nl, group);
n_ref ++;
r = hashmap_ensure_allocated(&nl->broadcast_group_refs, NULL);
if (r < 0)
return r;
r = broadcast_group_set_ref(nl, group, n_ref);
if (r < 0)
return r;
if (n_ref > 1)
/* not yet in the group */
return 0;
r = broadcast_group_join(nl, group);
if (r < 0)
return r;
return 0;
}
static int broadcast_group_leave(sd_netlink *nl, unsigned group) {
int r;
assert(nl);
assert(nl->fd >= 0);
assert(group > 0);
if (nl->broadcast_group_dont_leave)
return 0;
r = setsockopt(nl->fd, SOL_NETLINK, NETLINK_DROP_MEMBERSHIP, &group, sizeof(group));
if (r < 0)
return -errno;
return 0;
}
int socket_broadcast_group_unref(sd_netlink *nl, unsigned group) {
unsigned n_ref;
int r;
assert(nl);
n_ref = broadcast_group_get_ref(nl, group);
assert(n_ref > 0);
n_ref --;
r = broadcast_group_set_ref(nl, group, n_ref);
if (r < 0)
return r;
if (n_ref > 0)
/* still refs left */
return 0;
r = broadcast_group_leave(nl, group);
if (r < 0)
return r;
return 0;
}
/* returns the number of bytes sent, or a negative error code */
int socket_write_message(sd_netlink *nl, sd_netlink_message *m) {
union {
struct sockaddr sa;
struct sockaddr_nl nl;
} addr = {
.nl.nl_family = AF_NETLINK,
};
ssize_t k;
assert(nl);
assert(m);
assert(m->hdr);
k = sendto(nl->fd, m->hdr, m->hdr->nlmsg_len,
0, &addr.sa, sizeof(addr));
if (k < 0)
return -errno;
return k;
}
static int socket_recv_message(int fd, struct iovec *iov, uint32_t *_group, bool peek) {
union sockaddr_union sender;
uint8_t cmsg_buffer[CMSG_SPACE(sizeof(struct nl_pktinfo))];
struct msghdr msg = {
.msg_iov = iov,
.msg_iovlen = 1,
.msg_name = &sender,
.msg_namelen = sizeof(sender),
.msg_control = cmsg_buffer,
.msg_controllen = sizeof(cmsg_buffer),
};
struct cmsghdr *cmsg;
uint32_t group = 0;
int r;
assert(fd >= 0);
assert(iov);
r = recvmsg(fd, &msg, MSG_TRUNC | (peek ? MSG_PEEK : 0));
if (r < 0) {
/* no data */
if (errno == ENOBUFS)
log_debug("rtnl: kernel receive buffer overrun");
else if (errno == EAGAIN)
log_debug("rtnl: no data in socket");
return (errno == EAGAIN || errno == EINTR) ? 0 : -errno;
}
if (sender.nl.nl_pid != 0) {
/* not from the kernel, ignore */
log_debug("rtnl: ignoring message from portid %"PRIu32, sender.nl.nl_pid);
if (peek) {
/* drop the message */
r = recvmsg(fd, &msg, 0);
if (r < 0)
return (errno == EAGAIN || errno == EINTR) ? 0 : -errno;
}
return 0;
}
CMSG_FOREACH(cmsg, &msg) {
if (cmsg->cmsg_level == SOL_NETLINK &&
cmsg->cmsg_type == NETLINK_PKTINFO &&
cmsg->cmsg_len == CMSG_LEN(sizeof(struct nl_pktinfo))) {
struct nl_pktinfo *pktinfo = (void *)CMSG_DATA(cmsg);
/* multi-cast group */
group = pktinfo->group;
}
}
if (_group)
*_group = group;
return r;
}
/* On success, the number of bytes received is returned and *ret points to the received message
* which has a valid header and the correct size.
* If nothing useful was received 0 is returned.
* On failure, a negative error code is returned.
*/
int socket_read_message(sd_netlink *rtnl) {
_cleanup_(sd_netlink_message_unrefp) sd_netlink_message *first = NULL;
struct iovec iov = {};
uint32_t group = 0;
bool multi_part = false, done = false;
struct nlmsghdr *new_msg;
size_t len;
int r;
unsigned i = 0;
assert(rtnl);
assert(rtnl->rbuffer);
assert(rtnl->rbuffer_allocated >= sizeof(struct nlmsghdr));
/* read nothing, just get the pending message size */
r = socket_recv_message(rtnl->fd, &iov, NULL, true);
if (r <= 0)
return r;
else
len = (size_t)r;
/* make room for the pending message */
if (!greedy_realloc((void **)&rtnl->rbuffer,
&rtnl->rbuffer_allocated,
len, sizeof(uint8_t)))
return -ENOMEM;
iov.iov_base = rtnl->rbuffer;
iov.iov_len = rtnl->rbuffer_allocated;
/* read the pending message */
r = socket_recv_message(rtnl->fd, &iov, &group, false);
if (r <= 0)
return r;
else
len = (size_t)r;
if (len > rtnl->rbuffer_allocated)
/* message did not fit in read buffer */
return -EIO;
if (NLMSG_OK(rtnl->rbuffer, len) && rtnl->rbuffer->nlmsg_flags & NLM_F_MULTI) {
multi_part = true;
for (i = 0; i < rtnl->rqueue_partial_size; i++) {
if (rtnl_message_get_serial(rtnl->rqueue_partial[i]) ==
rtnl->rbuffer->nlmsg_seq) {
first = rtnl->rqueue_partial[i];
break;
}
}
}
for (new_msg = rtnl->rbuffer; NLMSG_OK(new_msg, len) && !done; new_msg = NLMSG_NEXT(new_msg, len)) {
_cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL;
const NLType *nl_type;
if (!group && new_msg->nlmsg_pid != rtnl->sockaddr.nl.nl_pid)
/* not broadcast and not for us */
continue;
if (new_msg->nlmsg_type == NLMSG_NOOP)
/* silently drop noop messages */
continue;
if (new_msg->nlmsg_type == NLMSG_DONE) {
/* finished reading multi-part message */
done = true;
/* if first is not defined, put NLMSG_DONE into the receive queue. */
if (first)
continue;
}
/* check that we support this message type */
r = type_system_get_type(&type_system_root, &nl_type, new_msg->nlmsg_type);
if (r < 0) {
if (r == -EOPNOTSUPP)
log_debug("sd-netlink: ignored message with unknown type: %i",
new_msg->nlmsg_type);
continue;
}
/* check that the size matches the message type */
if (new_msg->nlmsg_len < NLMSG_LENGTH(type_get_size(nl_type))) {
log_debug("sd-netlink: message larger than expected, dropping");
continue;
}
r = message_new_empty(rtnl, &m);
if (r < 0)
return r;
m->broadcast = !!group;
m->hdr = memdup(new_msg, new_msg->nlmsg_len);
if (!m->hdr)
return -ENOMEM;
/* seal and parse the top-level message */
r = sd_netlink_message_rewind(m);
if (r < 0)
return r;
/* push the message onto the multi-part message stack */
if (first)
m->next = first;
first = m;
m = NULL;
}
if (len)
log_debug("sd-netlink: discarding %zu bytes of incoming message", len);
if (!first)
return 0;
if (!multi_part || done) {
/* we got a complete message, push it on the read queue */
r = rtnl_rqueue_make_room(rtnl);
if (r < 0)
return r;
rtnl->rqueue[rtnl->rqueue_size ++] = first;
first = NULL;
if (multi_part && (i < rtnl->rqueue_partial_size)) {
/* remove the message form the partial read queue */
memmove(rtnl->rqueue_partial + i,rtnl->rqueue_partial + i + 1,
sizeof(sd_netlink_message*) * (rtnl->rqueue_partial_size - i - 1));
rtnl->rqueue_partial_size --;
}
return 1;
} else {
/* we only got a partial multi-part message, push it on the
partial read queue */
if (i < rtnl->rqueue_partial_size) {
rtnl->rqueue_partial[i] = first;
} else {
r = rtnl_rqueue_partial_make_room(rtnl);
if (r < 0)
return r;
rtnl->rqueue_partial[rtnl->rqueue_partial_size ++] = first;
}
first = NULL;
return 0;
}
}