389 lines
11 KiB
C
389 lines
11 KiB
C
/* SPDX-License-Identifier: LGPL-2.1-or-later */
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/***
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Copyright © 2014 Intel Corporation. All rights reserved.
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***/
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#include <netinet/icmp6.h>
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#include <netinet/in.h>
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#include "sd-ndisc.h"
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#include "alloc-util.h"
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#include "event-util.h"
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#include "fd-util.h"
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#include "icmp6-util.h"
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#include "in-addr-util.h"
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#include "memory-util.h"
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#include "ndisc-internal.h"
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#include "ndisc-router.h"
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#include "random-util.h"
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#include "socket-util.h"
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#include "string-table.h"
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#include "string-util.h"
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#define NDISC_TIMEOUT_NO_RA_USEC (NDISC_ROUTER_SOLICITATION_INTERVAL * NDISC_MAX_ROUTER_SOLICITATIONS)
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static const char * const ndisc_event_table[_SD_NDISC_EVENT_MAX] = {
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[SD_NDISC_EVENT_TIMEOUT] = "timeout",
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[SD_NDISC_EVENT_ROUTER] = "router",
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};
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DEFINE_STRING_TABLE_LOOKUP(ndisc_event, sd_ndisc_event);
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static void ndisc_callback(sd_ndisc *ndisc, sd_ndisc_event event, sd_ndisc_router *rt) {
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assert(ndisc);
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assert(event >= 0 && event < _SD_NDISC_EVENT_MAX);
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if (!ndisc->callback) {
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log_ndisc("Received '%s' event.", ndisc_event_to_string(event));
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return;
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}
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log_ndisc("Invoking callback for '%s' event.", ndisc_event_to_string(event));
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ndisc->callback(ndisc, event, rt, ndisc->userdata);
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}
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_public_ int sd_ndisc_set_callback(
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sd_ndisc *nd,
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sd_ndisc_callback_t callback,
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void *userdata) {
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assert_return(nd, -EINVAL);
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nd->callback = callback;
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nd->userdata = userdata;
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return 0;
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}
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_public_ int sd_ndisc_set_ifindex(sd_ndisc *nd, int ifindex) {
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assert_return(nd, -EINVAL);
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assert_return(ifindex > 0, -EINVAL);
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assert_return(nd->fd < 0, -EBUSY);
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nd->ifindex = ifindex;
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return 0;
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}
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_public_ int sd_ndisc_set_mac(sd_ndisc *nd, const struct ether_addr *mac_addr) {
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assert_return(nd, -EINVAL);
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if (mac_addr)
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nd->mac_addr = *mac_addr;
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else
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zero(nd->mac_addr);
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return 0;
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}
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_public_ int sd_ndisc_attach_event(sd_ndisc *nd, sd_event *event, int64_t priority) {
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int r;
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assert_return(nd, -EINVAL);
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assert_return(nd->fd < 0, -EBUSY);
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assert_return(!nd->event, -EBUSY);
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if (event)
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nd->event = sd_event_ref(event);
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else {
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r = sd_event_default(&nd->event);
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if (r < 0)
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return 0;
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}
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nd->event_priority = priority;
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return 0;
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}
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_public_ int sd_ndisc_detach_event(sd_ndisc *nd) {
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assert_return(nd, -EINVAL);
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assert_return(nd->fd < 0, -EBUSY);
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nd->event = sd_event_unref(nd->event);
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return 0;
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}
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_public_ sd_event *sd_ndisc_get_event(sd_ndisc *nd) {
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assert_return(nd, NULL);
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return nd->event;
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}
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static void ndisc_reset(sd_ndisc *nd) {
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assert(nd);
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(void) event_source_disable(nd->timeout_event_source);
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(void) event_source_disable(nd->timeout_no_ra);
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nd->retransmit_time = 0;
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nd->recv_event_source = sd_event_source_unref(nd->recv_event_source);
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nd->fd = safe_close(nd->fd);
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}
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static sd_ndisc *ndisc_free(sd_ndisc *nd) {
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assert(nd);
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nd->timeout_event_source = sd_event_source_unref(nd->timeout_event_source);
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nd->timeout_no_ra = sd_event_source_unref(nd->timeout_no_ra);
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ndisc_reset(nd);
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sd_ndisc_detach_event(nd);
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return mfree(nd);
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}
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DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_ndisc, sd_ndisc, ndisc_free);
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_public_ int sd_ndisc_new(sd_ndisc **ret) {
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_cleanup_(sd_ndisc_unrefp) sd_ndisc *nd = NULL;
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assert_return(ret, -EINVAL);
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nd = new(sd_ndisc, 1);
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if (!nd)
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return -ENOMEM;
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*nd = (sd_ndisc) {
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.n_ref = 1,
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.fd = -1,
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};
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*ret = TAKE_PTR(nd);
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return 0;
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}
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_public_ int sd_ndisc_get_mtu(sd_ndisc *nd, uint32_t *mtu) {
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assert_return(nd, -EINVAL);
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assert_return(mtu, -EINVAL);
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if (nd->mtu == 0)
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return -ENODATA;
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*mtu = nd->mtu;
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return 0;
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}
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_public_ int sd_ndisc_get_hop_limit(sd_ndisc *nd, uint8_t *ret) {
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assert_return(nd, -EINVAL);
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assert_return(ret, -EINVAL);
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if (nd->hop_limit == 0)
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return -ENODATA;
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*ret = nd->hop_limit;
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return 0;
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}
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static int ndisc_handle_datagram(sd_ndisc *nd, sd_ndisc_router *rt) {
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int r;
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assert(nd);
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assert(rt);
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r = ndisc_router_parse(rt);
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if (r == -EBADMSG) /* Bad packet */
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return 0;
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if (r < 0)
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return 0;
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/* Update global variables we keep */
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if (rt->mtu > 0)
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nd->mtu = rt->mtu;
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if (rt->hop_limit > 0)
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nd->hop_limit = rt->hop_limit;
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log_ndisc("Received Router Advertisement: flags %s preference %s lifetime %" PRIu16 " sec",
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rt->flags & ND_RA_FLAG_MANAGED ? "MANAGED" : rt->flags & ND_RA_FLAG_OTHER ? "OTHER" : "none",
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rt->preference == SD_NDISC_PREFERENCE_HIGH ? "high" : rt->preference == SD_NDISC_PREFERENCE_LOW ? "low" : "medium",
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rt->lifetime);
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ndisc_callback(nd, SD_NDISC_EVENT_ROUTER, rt);
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return 0;
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}
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static int ndisc_recv(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
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_cleanup_(sd_ndisc_router_unrefp) sd_ndisc_router *rt = NULL;
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sd_ndisc *nd = userdata;
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ssize_t buflen;
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int r;
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_cleanup_free_ char *addr = NULL;
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assert(s);
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assert(nd);
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assert(nd->event);
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buflen = next_datagram_size_fd(fd);
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if (buflen < 0)
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return log_ndisc_errno(buflen, "Failed to determine datagram size to read: %m");
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rt = ndisc_router_new(buflen);
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if (!rt)
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return -ENOMEM;
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r = icmp6_receive(fd, NDISC_ROUTER_RAW(rt), rt->raw_size, &rt->address, &rt->timestamp);
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if (r < 0) {
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switch (r) {
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case -EADDRNOTAVAIL:
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(void) in_addr_to_string(AF_INET6, (union in_addr_union*) &rt->address, &addr);
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log_ndisc("Received RA from non-link-local address %s. Ignoring", addr);
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break;
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case -EMULTIHOP:
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log_ndisc("Received RA with invalid hop limit. Ignoring.");
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break;
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case -EPFNOSUPPORT:
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log_ndisc("Received invalid source address from ICMPv6 socket. Ignoring.");
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break;
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case -EAGAIN: /* ignore spurious wakeups */
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break;
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default:
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log_ndisc_errno(r, "Unexpected error while reading from ICMPv6, ignoring: %m");
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break;
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}
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return 0;
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}
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(void) event_source_disable(nd->timeout_event_source);
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return ndisc_handle_datagram(nd, rt);
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}
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static usec_t ndisc_timeout_compute_random(usec_t val) {
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/* compute a time that is random within ±10% of the given value */
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return val - val / 10 +
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(random_u64() % (2 * USEC_PER_SEC)) * val / 10 / USEC_PER_SEC;
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}
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static int ndisc_timeout(sd_event_source *s, uint64_t usec, void *userdata) {
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char time_string[FORMAT_TIMESPAN_MAX];
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sd_ndisc *nd = userdata;
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usec_t time_now;
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int r;
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assert(s);
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assert(nd);
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assert(nd->event);
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assert_se(sd_event_now(nd->event, clock_boottime_or_monotonic(), &time_now) >= 0);
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if (!nd->retransmit_time)
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nd->retransmit_time = ndisc_timeout_compute_random(NDISC_ROUTER_SOLICITATION_INTERVAL);
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else {
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if (nd->retransmit_time > NDISC_MAX_ROUTER_SOLICITATION_INTERVAL / 2)
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nd->retransmit_time = ndisc_timeout_compute_random(NDISC_MAX_ROUTER_SOLICITATION_INTERVAL);
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else
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nd->retransmit_time += ndisc_timeout_compute_random(nd->retransmit_time);
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}
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r = event_reset_time(nd->event, &nd->timeout_event_source,
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clock_boottime_or_monotonic(),
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time_now + nd->retransmit_time, 10 * USEC_PER_MSEC,
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ndisc_timeout, nd,
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nd->event_priority, "ndisc-timeout-no-ra", true);
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if (r < 0)
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goto fail;
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r = icmp6_send_router_solicitation(nd->fd, &nd->mac_addr);
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if (r < 0) {
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log_ndisc_errno(r, "Error sending Router Solicitation: %m");
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goto fail;
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}
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log_ndisc("Sent Router Solicitation, next solicitation in %s",
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format_timespan(time_string, FORMAT_TIMESPAN_MAX,
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nd->retransmit_time, USEC_PER_SEC));
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return 0;
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fail:
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(void) sd_ndisc_stop(nd);
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return 0;
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}
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static int ndisc_timeout_no_ra(sd_event_source *s, uint64_t usec, void *userdata) {
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sd_ndisc *nd = userdata;
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assert(s);
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assert(nd);
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log_ndisc("No RA received before link confirmation timeout");
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(void) event_source_disable(nd->timeout_no_ra);
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ndisc_callback(nd, SD_NDISC_EVENT_TIMEOUT, NULL);
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return 0;
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}
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_public_ int sd_ndisc_stop(sd_ndisc *nd) {
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if (!nd)
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return 0;
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if (nd->fd < 0)
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return 0;
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log_ndisc("Stopping IPv6 Router Solicitation client");
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ndisc_reset(nd);
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return 1;
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}
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_public_ int sd_ndisc_start(sd_ndisc *nd) {
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int r;
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usec_t time_now;
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assert_return(nd, -EINVAL);
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assert_return(nd->event, -EINVAL);
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assert_return(nd->ifindex > 0, -EINVAL);
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if (nd->fd >= 0)
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return 0;
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assert(!nd->recv_event_source);
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r = sd_event_now(nd->event, clock_boottime_or_monotonic(), &time_now);
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if (r < 0)
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goto fail;
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nd->fd = icmp6_bind_router_solicitation(nd->ifindex);
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if (nd->fd < 0)
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return nd->fd;
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r = sd_event_add_io(nd->event, &nd->recv_event_source, nd->fd, EPOLLIN, ndisc_recv, nd);
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if (r < 0)
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goto fail;
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r = sd_event_source_set_priority(nd->recv_event_source, nd->event_priority);
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if (r < 0)
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goto fail;
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(void) sd_event_source_set_description(nd->recv_event_source, "ndisc-receive-message");
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r = event_reset_time(nd->event, &nd->timeout_event_source,
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clock_boottime_or_monotonic(),
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time_now + USEC_PER_SEC / 2, 1 * USEC_PER_SEC, /* See RFC 8415 sec. 18.2.1 */
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ndisc_timeout, nd,
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nd->event_priority, "ndisc-timeout", true);
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if (r < 0)
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goto fail;
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r = event_reset_time(nd->event, &nd->timeout_no_ra,
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clock_boottime_or_monotonic(),
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time_now + NDISC_TIMEOUT_NO_RA_USEC, 10 * USEC_PER_MSEC,
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ndisc_timeout_no_ra, nd,
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nd->event_priority, "ndisc-timeout-no-ra", true);
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if (r < 0)
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goto fail;
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log_ndisc("Started IPv6 Router Solicitation client");
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return 1;
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fail:
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ndisc_reset(nd);
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return r;
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}
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