diff options
Diffstat (limited to 'src/libsystemd-network/sd-ndisc.c')
| -rw-r--r-- | src/libsystemd-network/sd-ndisc.c | 381 |
1 files changed, 381 insertions, 0 deletions
diff --git a/src/libsystemd-network/sd-ndisc.c b/src/libsystemd-network/sd-ndisc.c new file mode 100644 index 0000000..1beed5d --- /dev/null +++ b/src/libsystemd-network/sd-ndisc.c @@ -0,0 +1,381 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ +/*** + Copyright © 2014 Intel Corporation. All rights reserved. +***/ + +#include <netinet/icmp6.h> +#include <netinet/in.h> + +#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 = -EBADF, + }; + + *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 %s", + 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", + FORMAT_TIMESPAN(rt->lifetime_usec, USEC_PER_SEC)); + + 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 (ERRNO_IS_NEG_TRANSIENT(buflen) || ERRNO_IS_NEG_DISCONNECT(buflen)) + return 0; + if (buflen < 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 (ERRNO_IS_NEG_TRANSIENT(r) || ERRNO_IS_NEG_DISCONNECT(r)) + return 0; + if (r < 0) + switch (r) { + case -EADDRNOTAVAIL: + log_ndisc(nd, "Received RA from neither link-local nor null address. Ignoring."); + return 0; + + case -EMULTIHOP: + log_ndisc(nd, "Received RA with invalid hop limit. Ignoring."); + return 0; + + case -EPFNOSUPPORT: + log_ndisc(nd, "Received invalid source address from ICMPv6 socket. Ignoring."); + return 0; + + default: + log_ndisc_errno(nd, r, "Unexpected error while reading from ICMPv6, ignoring: %m"); + return 0; + } + + /* The function icmp6_receive() accepts the null source address, but RFC 4861 Section 6.1.2 states + * that hosts MUST discard messages with the null source address. */ + if (in6_addr_is_null(&rt->address)) + log_ndisc(nd, "Received RA from null address. Ignoring."); + + (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; +} |