| /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
| |
| /*** |
| 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 "util.h" |
| #include "socket-util.h" |
| #include "formats-util.h" |
| #include "refcnt.h" |
| #include "missing.h" |
| |
| #include "sd-netlink.h" |
| #include "netlink-util.h" |
| #include "netlink-internal.h" |
| #include "netlink-types.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; |
| } |
| |
| 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; |
| |
| return 0; |
| } |
| |
| |
| int socket_join_broadcast_group(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; |
| } |
| |
| /* 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_netlink_message_unref_ 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_netlink_message_unref_ 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; |
| } |
| } |