| /*** |
| This file is part of systemd. |
| |
| Copyright (C) 2014 Intel Corporation. All rights reserved. |
| |
| 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/icmp6.h> |
| #include <netinet/in.h> |
| |
| #include "sd-ndisc.h" |
| |
| #include "alloc-util.h" |
| #include "fd-util.h" |
| #include "icmp6-util.h" |
| #include "in-addr-util.h" |
| #include "ndisc-internal.h" |
| #include "ndisc-router.h" |
| #include "socket-util.h" |
| #include "string-util.h" |
| #include "util.h" |
| |
| #define NDISC_ROUTER_SOLICITATION_INTERVAL (4U * USEC_PER_SEC) |
| #define NDISC_MAX_ROUTER_SOLICITATIONS 3U |
| |
| static void ndisc_callback(sd_ndisc *ndisc, sd_ndisc_event event, sd_ndisc_router *rt) { |
| assert(ndisc); |
| |
| log_ndisc("Invoking callback for '%c'.", event); |
| |
| if (!ndisc->callback) |
| return; |
| |
| ndisc->callback(ndisc, event, rt, ndisc->userdata); |
| } |
| |
| _public_ int sd_ndisc_set_callback( |
| sd_ndisc *nd, |
| sd_ndisc_callback_t callback, |
| void *userdata) { |
| |
| assert_return(nd, -EINVAL); |
| |
| nd->callback = callback; |
| nd->userdata = userdata; |
| |
| return 0; |
| } |
| |
| _public_ int sd_ndisc_set_ifindex(sd_ndisc *nd, int ifindex) { |
| assert_return(nd, -EINVAL); |
| assert_return(ifindex > 0, -EINVAL); |
| assert_return(nd->fd < 0, -EBUSY); |
| |
| nd->ifindex = ifindex; |
| return 0; |
| } |
| |
| _public_ int sd_ndisc_set_mac(sd_ndisc *nd, const struct ether_addr *mac_addr) { |
| assert_return(nd, -EINVAL); |
| |
| if (mac_addr) |
| nd->mac_addr = *mac_addr; |
| else |
| zero(nd->mac_addr); |
| |
| return 0; |
| } |
| |
| _public_ int sd_ndisc_attach_event(sd_ndisc *nd, sd_event *event, int64_t priority) { |
| int r; |
| |
| assert_return(nd, -EINVAL); |
| assert_return(nd->fd < 0, -EBUSY); |
| assert_return(!nd->event, -EBUSY); |
| |
| if (event) |
| nd->event = sd_event_ref(event); |
| else { |
| r = sd_event_default(&nd->event); |
| if (r < 0) |
| return 0; |
| } |
| |
| nd->event_priority = priority; |
| |
| return 0; |
| } |
| |
| _public_ int sd_ndisc_detach_event(sd_ndisc *nd) { |
| |
| assert_return(nd, -EINVAL); |
| assert_return(nd->fd < 0, -EBUSY); |
| |
| nd->event = sd_event_unref(nd->event); |
| return 0; |
| } |
| |
| _public_ sd_event *sd_ndisc_get_event(sd_ndisc *nd) { |
| assert_return(nd, NULL); |
| |
| return nd->event; |
| } |
| |
| _public_ sd_ndisc *sd_ndisc_ref(sd_ndisc *nd) { |
| |
| if (!nd) |
| return NULL; |
| |
| assert(nd->n_ref > 0); |
| nd->n_ref++; |
| |
| return nd; |
| } |
| |
| static int ndisc_reset(sd_ndisc *nd) { |
| assert(nd); |
| |
| nd->timeout_event_source = sd_event_source_unref(nd->timeout_event_source); |
| nd->recv_event_source = sd_event_source_unref(nd->recv_event_source); |
| nd->fd = safe_close(nd->fd); |
| |
| return 0; |
| } |
| |
| _public_ sd_ndisc *sd_ndisc_unref(sd_ndisc *nd) { |
| |
| if (!nd) |
| return NULL; |
| |
| assert(nd->n_ref > 0); |
| nd->n_ref--; |
| |
| if (nd->n_ref > 0) |
| return NULL; |
| |
| ndisc_reset(nd); |
| sd_ndisc_detach_event(nd); |
| free(nd); |
| |
| return NULL; |
| } |
| |
| _public_ int sd_ndisc_new(sd_ndisc **ret) { |
| _cleanup_(sd_ndisc_unrefp) sd_ndisc *nd = NULL; |
| |
| assert_return(ret, -EINVAL); |
| |
| nd = new0(sd_ndisc, 1); |
| if (!nd) |
| return -ENOMEM; |
| |
| nd->n_ref = 1; |
| nd->fd = -1; |
| |
| *ret = nd; |
| nd = NULL; |
| |
| return 0; |
| } |
| |
| _public_ int sd_ndisc_get_mtu(sd_ndisc *nd, uint32_t *mtu) { |
| assert_return(nd, -EINVAL); |
| assert_return(mtu, -EINVAL); |
| |
| if (nd->mtu == 0) |
| return -ENODATA; |
| |
| *mtu = nd->mtu; |
| return 0; |
| } |
| |
| _public_ int sd_ndisc_get_hop_limit(sd_ndisc *nd, uint8_t *ret) { |
| assert_return(nd, -EINVAL); |
| assert_return(ret, -EINVAL); |
| |
| if (nd->hop_limit == 0) |
| return -ENODATA; |
| |
| *ret = nd->hop_limit; |
| return 0; |
| } |
| |
| static int ndisc_handle_datagram(sd_ndisc *nd, sd_ndisc_router *rt) { |
| int r; |
| |
| assert(nd); |
| assert(rt); |
| |
| r = ndisc_router_parse(rt); |
| if (r == -EBADMSG) /* Bad packet */ |
| return 0; |
| if (r < 0) |
| return 0; |
| |
| /* Update global variables we keep */ |
| if (rt->mtu > 0) |
| nd->mtu = rt->mtu; |
| if (rt->hop_limit > 0) |
| nd->hop_limit = rt->hop_limit; |
| |
| log_ndisc("Received Router Advertisement: flags %s preference %s lifetime %" PRIu16 " sec", |
| rt->flags & ND_RA_FLAG_MANAGED ? "MANAGED" : rt->flags & ND_RA_FLAG_OTHER ? "OTHER" : "none", |
| rt->preference == SD_NDISC_PREFERENCE_HIGH ? "high" : rt->preference == SD_NDISC_PREFERENCE_LOW ? "low" : "medium", |
| rt->lifetime); |
| |
| ndisc_callback(nd, SD_NDISC_EVENT_ROUTER, rt); |
| return 0; |
| } |
| |
| static int ndisc_recv(sd_event_source *s, int fd, uint32_t revents, void *userdata) { |
| _cleanup_(sd_ndisc_router_unrefp) sd_ndisc_router *rt = NULL; |
| sd_ndisc *nd = userdata; |
| union { |
| struct cmsghdr cmsghdr; |
| uint8_t buf[CMSG_SPACE(sizeof(int)) + /* ttl */ |
| CMSG_SPACE(sizeof(struct timeval))]; |
| } control = {}; |
| struct iovec iov = {}; |
| union sockaddr_union sa = {}; |
| struct msghdr msg = { |
| .msg_name = &sa.sa, |
| .msg_namelen = sizeof(sa), |
| .msg_iov = &iov, |
| .msg_iovlen = 1, |
| .msg_control = &control, |
| .msg_controllen = sizeof(control), |
| }; |
| struct cmsghdr *cmsg; |
| ssize_t len, buflen; |
| |
| assert(s); |
| assert(nd); |
| assert(nd->event); |
| |
| buflen = next_datagram_size_fd(fd); |
| if (buflen < 0) |
| return log_ndisc_errno(buflen, "Failed to determine datagram size to read: %m"); |
| |
| rt = ndisc_router_new(buflen); |
| if (!rt) |
| return -ENOMEM; |
| |
| iov.iov_base = NDISC_ROUTER_RAW(rt); |
| iov.iov_len = rt->raw_size; |
| |
| len = recvmsg(fd, &msg, MSG_DONTWAIT); |
| if (len < 0) { |
| if (errno == EAGAIN || errno == EINTR) |
| return 0; |
| |
| return log_ndisc_errno(errno, "Could not receive message from ICMPv6 socket: %m"); |
| } |
| |
| if ((size_t) len != rt->raw_size) { |
| log_ndisc("Packet size mismatch."); |
| return -EINVAL; |
| } |
| |
| if (msg.msg_namelen == sizeof(struct sockaddr_in6) && |
| sa.in6.sin6_family == AF_INET6) { |
| |
| if (in_addr_is_link_local(AF_INET6, (union in_addr_union*) &sa.in6.sin6_addr) <= 0) { |
| _cleanup_free_ char *addr = NULL; |
| |
| (void) in_addr_to_string(AF_INET6, (union in_addr_union*) &sa.in6.sin6_addr, &addr); |
| log_ndisc("Received RA from non-link-local address %s. Ignoring.", strna(addr)); |
| return 0; |
| } |
| |
| rt->address = sa.in6.sin6_addr; |
| |
| } else if (msg.msg_namelen > 0) { |
| log_ndisc("Received invalid source address size from ICMPv6 socket: %zu bytes", (size_t) msg.msg_namelen); |
| return -EINVAL; |
| } |
| |
| /* namelen == 0 only happens when running the test-suite over a socketpair */ |
| |
| assert(!(msg.msg_flags & MSG_CTRUNC)); |
| assert(!(msg.msg_flags & MSG_TRUNC)); |
| |
| CMSG_FOREACH(cmsg, &msg) { |
| if (cmsg->cmsg_level == SOL_IPV6 && |
| cmsg->cmsg_type == IPV6_HOPLIMIT && |
| cmsg->cmsg_len == CMSG_LEN(sizeof(int))) { |
| int hops = *(int*) CMSG_DATA(cmsg); |
| |
| if (hops != 255) { |
| log_ndisc("Received RA with invalid hop limit %d. Ignoring.", hops); |
| return 0; |
| } |
| } |
| |
| if (cmsg->cmsg_level == SOL_SOCKET && |
| cmsg->cmsg_type == SO_TIMESTAMP && |
| cmsg->cmsg_len == CMSG_LEN(sizeof(struct timeval))) |
| triple_timestamp_from_realtime(&rt->timestamp, timeval_load((struct timeval*) CMSG_DATA(cmsg))); |
| } |
| |
| if (!triple_timestamp_is_set(&rt->timestamp)) |
| triple_timestamp_get(&rt->timestamp); |
| |
| nd->timeout_event_source = sd_event_source_unref(nd->timeout_event_source); |
| |
| return ndisc_handle_datagram(nd, rt); |
| } |
| |
| static int ndisc_timeout(sd_event_source *s, uint64_t usec, void *userdata) { |
| sd_ndisc *nd = userdata; |
| usec_t time_now, next_timeout; |
| int r; |
| |
| assert(s); |
| assert(nd); |
| assert(nd->event); |
| |
| if (nd->nd_sent >= NDISC_MAX_ROUTER_SOLICITATIONS) { |
| nd->timeout_event_source = sd_event_source_unref(nd->timeout_event_source); |
| ndisc_callback(nd, SD_NDISC_EVENT_TIMEOUT, NULL); |
| return 0; |
| } |
| |
| r = icmp6_send_router_solicitation(nd->fd, &nd->mac_addr); |
| if (r < 0) { |
| log_ndisc_errno(r, "Error sending Router Solicitation: %m"); |
| goto fail; |
| } |
| |
| log_ndisc("Sent Router Solicitation"); |
| nd->nd_sent++; |
| |
| assert_se(sd_event_now(nd->event, clock_boottime_or_monotonic(), &time_now) >= 0); |
| next_timeout = time_now + NDISC_ROUTER_SOLICITATION_INTERVAL; |
| |
| r = sd_event_source_set_time(nd->timeout_event_source, next_timeout); |
| if (r < 0) { |
| log_ndisc_errno(r, "Error updating timer: %m"); |
| goto fail; |
| } |
| |
| r = sd_event_source_set_enabled(nd->timeout_event_source, SD_EVENT_ONESHOT); |
| if (r < 0) { |
| log_ndisc_errno(r, "Error reenabling timer: %m"); |
| goto fail; |
| } |
| |
| return 0; |
| |
| fail: |
| sd_ndisc_stop(nd); |
| return 0; |
| } |
| |
| _public_ int sd_ndisc_stop(sd_ndisc *nd) { |
| assert_return(nd, -EINVAL); |
| |
| if (nd->fd < 0) |
| return 0; |
| |
| log_ndisc("Stopping IPv6 Router Solicitation client"); |
| |
| ndisc_reset(nd); |
| return 1; |
| } |
| |
| _public_ int sd_ndisc_start(sd_ndisc *nd) { |
| int r; |
| |
| assert_return(nd, -EINVAL); |
| assert_return(nd->event, -EINVAL); |
| assert_return(nd->ifindex > 0, -EINVAL); |
| |
| if (nd->fd >= 0) |
| return 0; |
| |
| assert(!nd->recv_event_source); |
| assert(!nd->timeout_event_source); |
| |
| nd->fd = icmp6_bind_router_solicitation(nd->ifindex); |
| if (nd->fd < 0) |
| return nd->fd; |
| |
| r = sd_event_add_io(nd->event, &nd->recv_event_source, nd->fd, EPOLLIN, ndisc_recv, nd); |
| if (r < 0) |
| goto fail; |
| |
| r = sd_event_source_set_priority(nd->recv_event_source, nd->event_priority); |
| if (r < 0) |
| goto fail; |
| |
| (void) sd_event_source_set_description(nd->recv_event_source, "ndisc-receive-message"); |
| |
| r = sd_event_add_time(nd->event, &nd->timeout_event_source, clock_boottime_or_monotonic(), 0, 0, ndisc_timeout, nd); |
| if (r < 0) |
| goto fail; |
| |
| r = sd_event_source_set_priority(nd->timeout_event_source, nd->event_priority); |
| if (r < 0) |
| goto fail; |
| |
| (void) sd_event_source_set_description(nd->timeout_event_source, "ndisc-timeout"); |
| |
| log_ndisc("Started IPv6 Router Solicitation client"); |
| return 1; |
| |
| fail: |
| ndisc_reset(nd); |
| return r; |
| } |