/* SPDX-License-Identifier: LGPL-2.1-or-later */ /*** Copyright © 2014 Intel Corporation. All rights reserved. ***/ #include #include #include "sd-ndisc.h" #include "alloc-util.h" #include "event-util.h" #include "fd-util.h" #include "icmp6-util.h" #include "in-addr-util.h" #include "memory-util.h" #include "ndisc-internal.h" #include "ndisc-router.h" #include "network-common.h" #include "random-util.h" #include "socket-util.h" #include "string-table.h" #include "string-util.h" #define NDISC_TIMEOUT_NO_RA_USEC (NDISC_ROUTER_SOLICITATION_INTERVAL * NDISC_MAX_ROUTER_SOLICITATIONS) static const char * const ndisc_event_table[_SD_NDISC_EVENT_MAX] = { [SD_NDISC_EVENT_TIMEOUT] = "timeout", [SD_NDISC_EVENT_ROUTER] = "router", }; DEFINE_STRING_TABLE_LOOKUP(ndisc_event, sd_ndisc_event_t); static void ndisc_callback(sd_ndisc *ndisc, sd_ndisc_event_t event, sd_ndisc_router *rt) { assert(ndisc); assert(event >= 0 && event < _SD_NDISC_EVENT_MAX); if (!ndisc->callback) return (void) log_ndisc(ndisc, "Received '%s' event.", ndisc_event_to_string(event)); log_ndisc(ndisc, "Invoking callback for '%s' event.", ndisc_event_to_string(event)); ndisc->callback(ndisc, event, rt, ndisc->userdata); } 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; } 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; } int sd_ndisc_set_ifname(sd_ndisc *nd, const char *ifname) { assert_return(nd, -EINVAL); assert_return(ifname, -EINVAL); if (!ifname_valid_full(ifname, IFNAME_VALID_ALTERNATIVE)) return -EINVAL; return free_and_strdup(&nd->ifname, ifname); } int sd_ndisc_get_ifname(sd_ndisc *nd, const char **ret) { int r; assert_return(nd, -EINVAL); r = get_ifname(nd->ifindex, &nd->ifname); if (r < 0) return r; if (ret) *ret = nd->ifname; return 0; } 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; } 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; } 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; } sd_event *sd_ndisc_get_event(sd_ndisc *nd) { assert_return(nd, NULL); return nd->event; } static void ndisc_reset(sd_ndisc *nd) { assert(nd); (void) event_source_disable(nd->timeout_event_source); (void) event_source_disable(nd->timeout_no_ra); nd->retransmit_time = 0; nd->recv_event_source = sd_event_source_disable_unref(nd->recv_event_source); nd->fd = safe_close(nd->fd); } static sd_ndisc *ndisc_free(sd_ndisc *nd) { assert(nd); ndisc_reset(nd); sd_event_source_unref(nd->timeout_event_source); sd_event_source_unref(nd->timeout_no_ra); sd_ndisc_detach_event(nd); free(nd->ifname); return mfree(nd); } DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_ndisc, sd_ndisc, ndisc_free); int sd_ndisc_new(sd_ndisc **ret) { _cleanup_(sd_ndisc_unrefp) sd_ndisc *nd = NULL; assert_return(ret, -EINVAL); nd = new(sd_ndisc, 1); if (!nd) return -ENOMEM; *nd = (sd_ndisc) { .n_ref = 1, .fd = -1, }; *ret = TAKE_PTR(nd); return 0; } static int ndisc_handle_datagram(sd_ndisc *nd, sd_ndisc_router *rt) { int r; assert(nd); assert(rt); r = ndisc_router_parse(nd, rt); if (r < 0) return r; log_ndisc(nd, "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 = ASSERT_PTR(userdata); ssize_t buflen; int r; assert(s); assert(nd->event); buflen = next_datagram_size_fd(fd); if (buflen < 0) { if (ERRNO_IS_TRANSIENT(buflen) || ERRNO_IS_DISCONNECT(buflen)) return 0; log_ndisc_errno(nd, buflen, "Failed to determine datagram size to read, ignoring: %m"); return 0; } rt = ndisc_router_new(buflen); if (!rt) return -ENOMEM; r = icmp6_receive(fd, NDISC_ROUTER_RAW(rt), rt->raw_size, &rt->address, &rt->timestamp); if (r < 0) { if (ERRNO_IS_TRANSIENT(r) || ERRNO_IS_DISCONNECT(r)) return 0; switch (r) { case -EADDRNOTAVAIL: log_ndisc(nd, "Received RA from non-link-local address %s. Ignoring.", IN6_ADDR_TO_STRING(&rt->address)); break; case -EMULTIHOP: log_ndisc(nd, "Received RA with invalid hop limit. Ignoring."); break; case -EPFNOSUPPORT: log_ndisc(nd, "Received invalid source address from ICMPv6 socket. Ignoring."); break; default: log_ndisc_errno(nd, r, "Unexpected error while reading from ICMPv6, ignoring: %m"); break; } return 0; } (void) event_source_disable(nd->timeout_event_source); (void) ndisc_handle_datagram(nd, rt); return 0; } static usec_t ndisc_timeout_compute_random(usec_t val) { /* compute a time that is random within ±10% of the given value */ return val - val / 10 + (random_u64() % (2 * USEC_PER_SEC)) * val / 10 / USEC_PER_SEC; } static int ndisc_timeout(sd_event_source *s, uint64_t usec, void *userdata) { sd_ndisc *nd = ASSERT_PTR(userdata); usec_t time_now; int r; assert(s); assert(nd->event); assert_se(sd_event_now(nd->event, CLOCK_BOOTTIME, &time_now) >= 0); if (!nd->retransmit_time) nd->retransmit_time = ndisc_timeout_compute_random(NDISC_ROUTER_SOLICITATION_INTERVAL); else { if (nd->retransmit_time > NDISC_MAX_ROUTER_SOLICITATION_INTERVAL / 2) nd->retransmit_time = ndisc_timeout_compute_random(NDISC_MAX_ROUTER_SOLICITATION_INTERVAL); else nd->retransmit_time += ndisc_timeout_compute_random(nd->retransmit_time); } r = event_reset_time(nd->event, &nd->timeout_event_source, CLOCK_BOOTTIME, time_now + nd->retransmit_time, 10 * USEC_PER_MSEC, ndisc_timeout, nd, nd->event_priority, "ndisc-timeout-no-ra", true); if (r < 0) goto fail; r = icmp6_send_router_solicitation(nd->fd, &nd->mac_addr); if (r < 0) log_ndisc_errno(nd, r, "Failed to send Router Solicitation, next solicitation in %s, ignoring: %m", FORMAT_TIMESPAN(nd->retransmit_time, USEC_PER_SEC)); else log_ndisc(nd, "Sent Router Solicitation, next solicitation in %s", FORMAT_TIMESPAN(nd->retransmit_time, USEC_PER_SEC)); return 0; fail: (void) sd_ndisc_stop(nd); return 0; } static int ndisc_timeout_no_ra(sd_event_source *s, uint64_t usec, void *userdata) { sd_ndisc *nd = ASSERT_PTR(userdata); assert(s); log_ndisc(nd, "No RA received before link confirmation timeout"); (void) event_source_disable(nd->timeout_no_ra); ndisc_callback(nd, SD_NDISC_EVENT_TIMEOUT, NULL); return 0; } int sd_ndisc_stop(sd_ndisc *nd) { if (!nd) return 0; if (nd->fd < 0) return 0; log_ndisc(nd, "Stopping IPv6 Router Solicitation client"); ndisc_reset(nd); return 1; } int sd_ndisc_start(sd_ndisc *nd) { int r; usec_t time_now; 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); r = sd_event_now(nd->event, CLOCK_BOOTTIME, &time_now); if (r < 0) goto fail; 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 = event_reset_time(nd->event, &nd->timeout_event_source, CLOCK_BOOTTIME, time_now + USEC_PER_SEC / 2, 1 * USEC_PER_SEC, /* See RFC 8415 sec. 18.2.1 */ ndisc_timeout, nd, nd->event_priority, "ndisc-timeout", true); if (r < 0) goto fail; r = event_reset_time(nd->event, &nd->timeout_no_ra, CLOCK_BOOTTIME, time_now + NDISC_TIMEOUT_NO_RA_USEC, 10 * USEC_PER_MSEC, ndisc_timeout_no_ra, nd, nd->event_priority, "ndisc-timeout-no-ra", true); if (r < 0) goto fail; log_ndisc(nd, "Started IPv6 Router Solicitation client"); return 1; fail: ndisc_reset(nd); return r; }