diff options
Diffstat (limited to 'trunk/avahi-core/netlink.c')
| -rw-r--r-- | trunk/avahi-core/netlink.c | 211 |
1 files changed, 211 insertions, 0 deletions
diff --git a/trunk/avahi-core/netlink.c b/trunk/avahi-core/netlink.c new file mode 100644 index 0000000..7411c90 --- /dev/null +++ b/trunk/avahi-core/netlink.c @@ -0,0 +1,211 @@ +/* $Id$ */ + +/*** + This file is part of avahi. + + avahi 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. + + avahi 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 avahi; if not, write to the Free Software + Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 + USA. +***/ + +#ifdef HAVE_CONFIG_H +#include <config.h> +#endif + +#include <unistd.h> +#include <errno.h> +#include <string.h> +#include <sys/ioctl.h> +#include <assert.h> + +#include <avahi-common/malloc.h> +#include "netlink.h" +#include "log.h" + +struct AvahiNetlink { + int fd; + unsigned seq; + AvahiNetlinkCallback callback; + void* userdata; + uint8_t* buffer; + size_t buffer_length; + + const AvahiPoll *poll_api; + AvahiWatch *watch; +}; + +int avahi_netlink_work(AvahiNetlink *nl, int block) { + ssize_t bytes; + struct msghdr smsg; + struct cmsghdr *cmsg; + struct ucred *cred; + struct iovec iov; + struct nlmsghdr *p; + char cred_msg[CMSG_SPACE(sizeof(struct ucred))]; + + assert(nl); + + iov.iov_base = nl->buffer; + iov.iov_len = nl->buffer_length; + + smsg.msg_name = (void*) NULL; + smsg.msg_namelen = 0; + smsg.msg_iov = &iov; + smsg.msg_iovlen = 1; + smsg.msg_control = cred_msg; + smsg.msg_controllen = sizeof(cred_msg); + smsg.msg_flags = (block ? 0 : MSG_DONTWAIT); + + if ((bytes = recvmsg(nl->fd, &smsg, 0)) < 0) { + if (errno == EAGAIN || errno == EINTR) + return 0; + + avahi_log_error(__FILE__": recvmsg() failed: %s", strerror(errno)); + return -1; + } + + cmsg = CMSG_FIRSTHDR(&smsg); + cred = (struct ucred *) CMSG_DATA (cmsg); + + if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) { + avahi_log_error("No sender credentials received, ignoring data."); + return -1; + } + + if (cred->uid != 0) { + avahi_log_warn("Netlink message received from cred->uid != 0 (%d)", cred->uid); + return -1; + } + + p = (struct nlmsghdr *) nl->buffer; + + assert(nl->callback); + + for (; bytes > 0; p = NLMSG_NEXT(p, bytes)) { + if (!NLMSG_OK(p, (size_t) bytes)) { + avahi_log_warn(__FILE__": packet truncated"); + return -1; + } + + nl->callback(nl, p, nl->userdata); + } + + return 0; +} + +static void socket_event(AvahiWatch *w, int fd, AVAHI_GCC_UNUSED AvahiWatchEvent event, void *userdata) { + AvahiNetlink *nl = userdata; + + assert(w); + assert(nl); + assert(fd == nl->fd); + + avahi_netlink_work(nl, 0); +} + +AvahiNetlink *avahi_netlink_new(const AvahiPoll *poll_api, uint32_t groups, void (*cb) (AvahiNetlink *nl, struct nlmsghdr *n, void* userdata), void* userdata) { + int fd = -1; + const int on = 1; + struct sockaddr_nl addr; + AvahiNetlink *nl = NULL; + + assert(poll_api); + assert(cb); + + if ((fd = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE)) < 0) { + avahi_log_error(__FILE__": socket(PF_NETLINK): %s", strerror(errno)); + return NULL; + } + + memset(&addr, 0, sizeof(addr)); + addr.nl_family = AF_NETLINK; + addr.nl_groups = groups; + addr.nl_pid = getpid(); + + if (bind(fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) { + avahi_log_error(__FILE__": bind(): %s", strerror(errno)); + goto fail; + } + + if (setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on)) < 0) { + avahi_log_error(__FILE__": bind(): %s", strerror(errno)); + goto fail; + } + + if (!(nl = avahi_new(AvahiNetlink, 1))) { + avahi_log_error(__FILE__": avahi_new() failed."); + goto fail; + } + + nl->poll_api = poll_api; + nl->fd = fd; + nl->seq = 0; + nl->callback = cb; + nl->userdata = userdata; + + if (!(nl->buffer = avahi_new(uint8_t, nl->buffer_length = 64*1024))) { + avahi_log_error(__FILE__": avahi_new() failed."); + goto fail; + } + + if (!(nl->watch = poll_api->watch_new(poll_api, fd, AVAHI_WATCH_IN, socket_event, nl))) { + avahi_log_error(__FILE__": Failed to create watch."); + goto fail; + } + + return nl; + +fail: + + if (fd >= 0) + close(fd); + + if (nl) { + avahi_free(nl->buffer); + avahi_free(nl); + } + + return NULL; +} + +void avahi_netlink_free(AvahiNetlink *nl) { + assert(nl); + + if (nl->watch) + nl->poll_api->watch_free(nl->watch); + + if (nl->fd >= 0) + close(nl->fd); + + avahi_free(nl->buffer); + avahi_free(nl); +} + +int avahi_netlink_send(AvahiNetlink *nl, struct nlmsghdr *m, unsigned *ret_seq) { + assert(nl); + assert(m); + + m->nlmsg_seq = nl->seq++; + m->nlmsg_flags |= NLM_F_ACK; + + if (send(nl->fd, m, m->nlmsg_len, 0) < 0) { + avahi_log_error(__FILE__": send(): %s", strerror(errno)); + return -1; + } + + if (ret_seq) + *ret_seq = m->nlmsg_seq; + + return 0; +} |