/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ /*** This file is part of systemd. Copyright 2013 Tom Gundersen 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 . ***/ #include #include #include #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(NULL, &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(nl_type->size)) { 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; } }