sd-icmp6-nd.c revision ed19c567e5fcdcec1a2b6dbac63787e001ad5d55
/***
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/ip6.h>
#include <string.h>
#include <stdbool.h>
#include <netinet/in.h>
#include <sys/ioctl.h>
#include "socket-util.h"
#include "async.h"
#include "dhcp6-internal.h"
#include "sd-icmp6-nd.h"
#define ICMP6_ROUTER_SOLICITATION_INTERVAL 4 * USEC_PER_SEC
#define ICMP6_MAX_ROUTER_SOLICITATIONS 3
enum icmp6_nd_state {
ICMP6_NEIGHBOR_DISCOVERY_IDLE = 0,
ICMP6_ROUTER_SOLICITATION_SENT = 10,
ICMP6_ROUTER_ADVERTISMENT_LISTEN = 11,
};
#define IP6_MIN_MTU (unsigned)1280
#define ICMP6_ND_RECV_SIZE (IP6_MIN_MTU - sizeof(struct ip6_hdr))
#define ICMP6_OPT_LEN_UNITS 8
typedef struct ICMP6Prefix ICMP6Prefix;
struct ICMP6Prefix {
unsigned n_ref;
LIST_FIELDS(ICMP6Prefix, prefixes);
uint8_t len;
sd_event_source *timeout_valid;
struct in6_addr addr;
};
struct sd_icmp6_nd {
unsigned n_ref;
enum icmp6_nd_state state;
sd_event *event;
int event_priority;
int index;
struct ether_addr mac_addr;
uint32_t mtu;
ICMP6Prefix *expired_prefix;
LIST_HEAD(ICMP6Prefix, prefixes);
int fd;
sd_event_source *recv;
sd_event_source *timeout;
int nd_sent;
sd_icmp6_nd_callback_t callback;
void *userdata;
};
#define log_icmp6_nd(p, fmt, ...) log_internal(LOG_DEBUG, 0, __FILE__, __LINE__, __func__, "ICMPv6 CLIENT: " fmt, ##__VA_ARGS__)
static ICMP6Prefix *icmp6_prefix_unref(ICMP6Prefix *prefix) {
if (!prefix)
return NULL;
assert(prefix->n_ref > 0);
prefix->n_ref--;
if (prefix->n_ref > 0)
return NULL;
prefix->timeout_valid = sd_event_source_unref(prefix->timeout_valid);
free(prefix);
return NULL;
}
static int icmp6_prefix_new(ICMP6Prefix **ret) {
_cleanup_free_ ICMP6Prefix *prefix = NULL;
assert(ret);
prefix = new0(ICMP6Prefix, 1);
if (!prefix)
return -ENOMEM;
prefix->n_ref = 1;
LIST_INIT(prefixes, prefix);
*ret = prefix;
prefix = NULL;
return 0;
}
static void icmp6_nd_notify(sd_icmp6_nd *nd, int event) {
if (nd->callback)
nd->callback(nd, event, nd->userdata);
}
int sd_icmp6_nd_set_callback(sd_icmp6_nd *nd, sd_icmp6_nd_callback_t callback,
void *userdata) {
assert(nd);
nd->callback = callback;
nd->userdata = userdata;
return 0;
}
int sd_icmp6_nd_set_index(sd_icmp6_nd *nd, int interface_index) {
assert(nd);
assert(interface_index >= -1);
nd->index = interface_index;
return 0;
}
int sd_icmp6_nd_set_mac(sd_icmp6_nd *nd, const struct ether_addr *mac_addr) {
assert(nd);
if (mac_addr)
memcpy(&nd->mac_addr, mac_addr, sizeof(nd->mac_addr));
else
zero(nd->mac_addr);
return 0;
}
int sd_icmp6_nd_attach_event(sd_icmp6_nd *nd, sd_event *event, int priority) {
int r;
assert_return(nd, -EINVAL);
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_icmp6_nd_detach_event(sd_icmp6_nd *nd) {
assert_return(nd, -EINVAL);
nd->event = sd_event_unref(nd->event);
return 0;
}
sd_event *sd_icmp6_nd_get_event(sd_icmp6_nd *nd) {
assert(nd);
return nd->event;
}
sd_icmp6_nd *sd_icmp6_nd_ref(sd_icmp6_nd *nd) {
if (!nd)
return NULL;
assert(nd->n_ref > 0);
nd->n_ref++;
return nd;
}
static int icmp6_nd_init(sd_icmp6_nd *nd) {
assert(nd);
nd->recv = sd_event_source_unref(nd->recv);
nd->fd = asynchronous_close(nd->fd);
nd->timeout = sd_event_source_unref(nd->timeout);
return 0;
}
sd_icmp6_nd *sd_icmp6_nd_unref(sd_icmp6_nd *nd) {
ICMP6Prefix *prefix, *p;
if (!nd)
return NULL;
assert(nd->n_ref > 0);
nd->n_ref--;
if (nd->n_ref > 0)
return NULL;
icmp6_nd_init(nd);
sd_icmp6_nd_detach_event(nd);
LIST_FOREACH_SAFE(prefixes, prefix, p, nd->prefixes) {
LIST_REMOVE(prefixes, nd->prefixes, prefix);
prefix = icmp6_prefix_unref(prefix);
}
free(nd);
return NULL;
}
DEFINE_TRIVIAL_CLEANUP_FUNC(sd_icmp6_nd*, sd_icmp6_nd_unref);
#define _cleanup_sd_icmp6_nd_free_ _cleanup_(sd_icmp6_nd_unrefp)
int sd_icmp6_nd_new(sd_icmp6_nd **ret) {
_cleanup_sd_icmp6_nd_free_ sd_icmp6_nd *nd = NULL;
assert(ret);
nd = new0(sd_icmp6_nd, 1);
if (!nd)
return -ENOMEM;
nd->n_ref = 1;
nd->index = -1;
nd->fd = -1;
LIST_HEAD_INIT(nd->prefixes);
*ret = nd;
nd = NULL;
return 0;
}
int sd_icmp6_ra_get_mtu(sd_icmp6_nd *nd, uint32_t *mtu) {
assert_return(nd, -EINVAL);
assert_return(mtu, -EINVAL);
if (nd->mtu == 0)
return -ENOMSG;
*mtu = nd->mtu;
return 0;
}
static int icmp6_ra_prefix_timeout(sd_event_source *s, uint64_t usec,
void *userdata) {
sd_icmp6_nd *nd = userdata;
ICMP6Prefix *prefix, *p;
assert(nd);
LIST_FOREACH_SAFE(prefixes, prefix, p, nd->prefixes) {
if (prefix->timeout_valid != s)
continue;
log_icmp6_nd(nd, "Prefix expired "SD_ICMP6_ND_ADDRESS_FORMAT_STR"/%d",
SD_ICMP6_ND_ADDRESS_FORMAT_VAL(prefix->addr),
prefix->len);
LIST_REMOVE(prefixes, nd->prefixes, prefix);
nd->expired_prefix = prefix;
icmp6_nd_notify(nd,
SD_ICMP6_ND_EVENT_ROUTER_ADVERTISMENT_PREFIX_EXPIRED);
nd->expired_prefix = NULL;
prefix = icmp6_prefix_unref(prefix);
break;
}
return 0;
}
static int icmp6_ra_prefix_set_timeout(sd_icmp6_nd *nd,
ICMP6Prefix *prefix,
usec_t valid) {
usec_t time_now;
int r;
assert_return(prefix, -EINVAL);
r = sd_event_now(nd->event, clock_boottime_or_monotonic(), &time_now);
if (r < 0)
return r;
prefix->timeout_valid = sd_event_source_unref(prefix->timeout_valid);
r = sd_event_add_time(nd->event, &prefix->timeout_valid,
clock_boottime_or_monotonic(), time_now + valid,
USEC_PER_SEC, icmp6_ra_prefix_timeout, nd);
if (r < 0)
goto error;
r = sd_event_source_set_priority(prefix->timeout_valid,
nd->event_priority);
if (r < 0)
goto error;
r = sd_event_source_set_description(prefix->timeout_valid,
"icmp6-prefix-timeout");
error:
if (r < 0)
prefix->timeout_valid =
sd_event_source_unref(prefix->timeout_valid);
return r;
}
static int icmp6_prefix_match(const struct in6_addr *prefix, uint8_t prefixlen,
const struct in6_addr *addr,
uint8_t addr_prefixlen) {
uint8_t bytes, mask, len;
assert_return(prefix, -EINVAL);
assert_return(addr, -EINVAL);
len = MIN(prefixlen, addr_prefixlen);
bytes = len / 8;
mask = 0xff << (8 - len % 8);
if (memcmp(prefix, addr, bytes) != 0 ||
(prefix->s6_addr[bytes] & mask) != (addr->s6_addr[bytes] & mask))
return -EADDRNOTAVAIL;
return 0;
}
static int icmp6_ra_prefix_match(ICMP6Prefix *head, const struct in6_addr *addr,
uint8_t addr_len, ICMP6Prefix **result) {
ICMP6Prefix *prefix;
LIST_FOREACH(prefixes, prefix, head) {
if (icmp6_prefix_match(&prefix->addr, prefix->len, addr,
addr_len) >= 0) {
*result = prefix;
return 0;
}
}
return -EADDRNOTAVAIL;
}
int sd_icmp6_prefix_match(struct in6_addr *prefix, uint8_t prefixlen,
struct in6_addr *addr) {
return icmp6_prefix_match(prefix, prefixlen, addr,
sizeof(addr->s6_addr) * 8);
}
int sd_icmp6_ra_get_prefixlen(sd_icmp6_nd *nd, const struct in6_addr *addr,
uint8_t *prefixlen) {
int r;
ICMP6Prefix *prefix;
assert_return(nd, -EINVAL);
assert_return(addr, -EINVAL);
assert_return(prefixlen, -EINVAL);
r = icmp6_ra_prefix_match(nd->prefixes, addr,
sizeof(addr->s6_addr) * 8, &prefix);
if (r < 0)
return r;
*prefixlen = prefix->len;
return 0;
}
int sd_icmp6_ra_get_expired_prefix(sd_icmp6_nd *nd, struct in6_addr **addr, uint8_t *prefixlen) {
assert_return(nd, -EINVAL);
assert_return(addr, -EINVAL);
assert_return(prefixlen, -EINVAL);
if (!nd->expired_prefix)
return -EADDRNOTAVAIL;
*addr = &nd->expired_prefix->addr;
*prefixlen = nd->expired_prefix->len;
return 0;
}
static int icmp6_ra_prefix_update(sd_icmp6_nd *nd, ssize_t len,
const struct nd_opt_prefix_info *prefix_opt) {
int r;
ICMP6Prefix *prefix;
uint32_t lifetime;
char time_string[FORMAT_TIMESPAN_MAX];
assert_return(nd, -EINVAL);
assert_return(prefix_opt, -EINVAL);
if (len < prefix_opt->nd_opt_pi_len)
return -ENOMSG;
if (!(prefix_opt->nd_opt_pi_flags_reserved & ND_OPT_PI_FLAG_ONLINK))
return 0;
lifetime = be32toh(prefix_opt->nd_opt_pi_valid_time);
r = icmp6_ra_prefix_match(nd->prefixes,
&prefix_opt->nd_opt_pi_prefix,
prefix_opt->nd_opt_pi_prefix_len, &prefix);
if (r < 0 && r != -EADDRNOTAVAIL)
return r;
/* if router advertisment prefix valid timeout is zero, the timeout
callback will be called immediately to clean up the prefix */
if (r == -EADDRNOTAVAIL) {
r = icmp6_prefix_new(&prefix);
if (r < 0)
return r;
prefix->len = prefix_opt->nd_opt_pi_prefix_len;
memcpy(&prefix->addr, &prefix_opt->nd_opt_pi_prefix,
sizeof(prefix->addr));
log_icmp6_nd(nd, "New prefix "SD_ICMP6_ND_ADDRESS_FORMAT_STR"/%d lifetime %d expires in %s",
SD_ICMP6_ND_ADDRESS_FORMAT_VAL(prefix->addr),
prefix->len, lifetime,
format_timespan(time_string, FORMAT_TIMESPAN_MAX, lifetime * USEC_PER_SEC, USEC_PER_SEC));
LIST_PREPEND(prefixes, nd->prefixes, prefix);
} else {
if (prefix->len != prefix_opt->nd_opt_pi_prefix_len) {
uint8_t prefixlen;
prefixlen = MIN(prefix->len, prefix_opt->nd_opt_pi_prefix_len);
log_icmp6_nd(nd, "Prefix length mismatch %d/%d using %d",
prefix->len,
prefix_opt->nd_opt_pi_prefix_len,
prefixlen);
prefix->len = prefixlen;
}
log_icmp6_nd(nd, "Update prefix "SD_ICMP6_ND_ADDRESS_FORMAT_STR"/%d lifetime %d expires in %s",
SD_ICMP6_ND_ADDRESS_FORMAT_VAL(prefix->addr),
prefix->len, lifetime,
format_timespan(time_string, FORMAT_TIMESPAN_MAX, lifetime * USEC_PER_SEC, USEC_PER_SEC));
}
r = icmp6_ra_prefix_set_timeout(nd, prefix, lifetime * USEC_PER_SEC);
return r;
}
static int icmp6_ra_parse(sd_icmp6_nd *nd, struct nd_router_advert *ra,
ssize_t len) {
void *opt;
struct nd_opt_hdr *opt_hdr;
assert_return(nd, -EINVAL);
assert_return(ra, -EINVAL);
len -= sizeof(*ra);
if (len < ICMP6_OPT_LEN_UNITS) {
log_icmp6_nd(nd, "Router Advertisement below minimum length");
return -ENOMSG;
}
opt = ra + 1;
opt_hdr = opt;
while (len != 0 && len >= opt_hdr->nd_opt_len * ICMP6_OPT_LEN_UNITS) {
struct nd_opt_mtu *opt_mtu;
uint32_t mtu;
struct nd_opt_prefix_info *opt_prefix;
if (opt_hdr->nd_opt_len == 0)
return -ENOMSG;
switch (opt_hdr->nd_opt_type) {
case ND_OPT_MTU:
opt_mtu = opt;
mtu = be32toh(opt_mtu->nd_opt_mtu_mtu);
if (mtu != nd->mtu) {
nd->mtu = MAX(mtu, IP6_MIN_MTU);
log_icmp6_nd(nd, "Router Advertisement link MTU %d using %d",
mtu, nd->mtu);
}
break;
case ND_OPT_PREFIX_INFORMATION:
opt_prefix = opt;
icmp6_ra_prefix_update(nd, len, opt_prefix);
break;
}
len -= opt_hdr->nd_opt_len * ICMP6_OPT_LEN_UNITS;
opt = (void *)((char *)opt +
opt_hdr->nd_opt_len * ICMP6_OPT_LEN_UNITS);
opt_hdr = opt;
}
if (len > 0)
log_icmp6_nd(nd, "Router Advertisement contains %zd bytes of trailing garbage", len);
return 0;
}
static int icmp6_router_advertisment_recv(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
sd_icmp6_nd *nd = userdata;
int r, buflen = 0;
ssize_t len;
_cleanup_free_ struct nd_router_advert *ra = NULL;
int event = SD_ICMP6_ND_EVENT_ROUTER_ADVERTISMENT_NONE;
assert(s);
assert(nd);
assert(nd->event);
r = ioctl(fd, FIONREAD, &buflen);
if (r < 0 || buflen <= 0)
buflen = ICMP6_ND_RECV_SIZE;
ra = malloc(buflen);
if (!ra)
return -ENOMEM;
len = read(fd, ra, buflen);
if (len < 0) {
log_icmp6_nd(nd, "Could not receive message from UDP socket: %m");
return 0;
}
if (ra->nd_ra_type != ND_ROUTER_ADVERT)
return 0;
if (ra->nd_ra_code != 0)
return 0;
nd->timeout = sd_event_source_unref(nd->timeout);
nd->state = ICMP6_ROUTER_ADVERTISMENT_LISTEN;
if (ra->nd_ra_flags_reserved & ND_RA_FLAG_OTHER )
event = SD_ICMP6_ND_EVENT_ROUTER_ADVERTISMENT_OTHER;
if (ra->nd_ra_flags_reserved & ND_RA_FLAG_MANAGED)
event = SD_ICMP6_ND_EVENT_ROUTER_ADVERTISMENT_MANAGED;
log_icmp6_nd(nd, "Received Router Advertisement flags %s/%s",
ra->nd_ra_flags_reserved & ND_RA_FLAG_MANAGED? "MANAGED": "none",
ra->nd_ra_flags_reserved & ND_RA_FLAG_OTHER? "OTHER": "none");
if (event != SD_ICMP6_ND_EVENT_ROUTER_ADVERTISMENT_NONE) {
r = icmp6_ra_parse(nd, ra, len);
if (r < 0) {
log_icmp6_nd(nd, "Could not parse Router Advertisement: %s",
strerror(-r));
return 0;
}
}
icmp6_nd_notify(nd, event);
return 0;
}
static int icmp6_router_solicitation_timeout(sd_event_source *s, uint64_t usec, void *userdata) {
sd_icmp6_nd *nd = userdata;
uint64_t time_now, next_timeout;
struct ether_addr unset = { };
struct ether_addr *addr = NULL;
int r;
assert(s);
assert(nd);
assert(nd->event);
nd->timeout = sd_event_source_unref(nd->timeout);
if (nd->nd_sent >= ICMP6_MAX_ROUTER_SOLICITATIONS) {
icmp6_nd_notify(nd, SD_ICMP6_ND_EVENT_ROUTER_ADVERTISMENT_TIMEOUT);
nd->state = ICMP6_ROUTER_ADVERTISMENT_LISTEN;
} else {
if (memcmp(&nd->mac_addr, &unset, sizeof(struct ether_addr)))
addr = &nd->mac_addr;
r = dhcp_network_icmp6_send_router_solicitation(nd->fd, addr);
if (r < 0)
log_icmp6_nd(nd, "Error sending Router Solicitation");
else {
nd->state = ICMP6_ROUTER_SOLICITATION_SENT;
log_icmp6_nd(nd, "Sent Router Solicitation");
}
nd->nd_sent++;
r = sd_event_now(nd->event, clock_boottime_or_monotonic(), &time_now);
if (r < 0) {
icmp6_nd_notify(nd, r);
return 0;
}
next_timeout = time_now + ICMP6_ROUTER_SOLICITATION_INTERVAL;
r = sd_event_add_time(nd->event, &nd->timeout, clock_boottime_or_monotonic(),
next_timeout, 0,
icmp6_router_solicitation_timeout, nd);
if (r < 0) {
icmp6_nd_notify(nd, r);
return 0;
}
r = sd_event_source_set_priority(nd->timeout,
nd->event_priority);
if (r < 0) {
icmp6_nd_notify(nd, r);
return 0;
}
r = sd_event_source_set_description(nd->timeout, "icmp6-timeout");
if (r < 0) {
icmp6_nd_notify(nd, r);
return 0;
}
}
return 0;
}
int sd_icmp6_nd_stop(sd_icmp6_nd *nd) {
assert_return(nd, -EINVAL);
assert_return(nd->event, -EINVAL);
log_icmp6_nd(client, "Stop ICMPv6");
icmp6_nd_init(nd);
nd->state = ICMP6_NEIGHBOR_DISCOVERY_IDLE;
return 0;
}
int sd_icmp6_router_solicitation_start(sd_icmp6_nd *nd) {
int r;
assert(nd);
assert(nd->event);
if (nd->state != ICMP6_NEIGHBOR_DISCOVERY_IDLE)
return -EINVAL;
if (nd->index < 1)
return -EINVAL;
r = dhcp_network_icmp6_bind_router_solicitation(nd->index);
if (r < 0)
return r;
nd->fd = r;
r = sd_event_add_io(nd->event, &nd->recv, nd->fd, EPOLLIN,
icmp6_router_advertisment_recv, nd);
if (r < 0)
goto error;
r = sd_event_source_set_priority(nd->recv, nd->event_priority);
if (r < 0)
goto error;
r = sd_event_source_set_description(nd->recv, "icmp6-receive-message");
if (r < 0)
goto error;
r = sd_event_add_time(nd->event, &nd->timeout, clock_boottime_or_monotonic(),
0, 0, icmp6_router_solicitation_timeout, nd);
if (r < 0)
goto error;
r = sd_event_source_set_priority(nd->timeout, nd->event_priority);
if (r < 0)
goto error;
r = sd_event_source_set_description(nd->timeout, "icmp6-timeout");
error:
if (r < 0)
icmp6_nd_init(nd);
else
log_icmp6_nd(client, "Start Router Solicitation");
return r;
}