| /*** |
| 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 = 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); |
| |
| if (!cmsg || cmsg->cmsg_type != SCM_CREDENTIALS) { |
| avahi_log_warn("No sender credentials received, ignoring data."); |
| return -1; |
| } |
| |
| cred = (struct ucred*) CMSG_DATA(cmsg); |
| |
| if (cred->pid != 0) |
| 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 = 0; |
| |
| 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__": SO_PASSCRED: %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; |
| } |