picnoir
/
Systemd
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity
Systemd/src/libsystemd-network/sd-ipv4acd.c

528 lines
15 KiB
C
Raw Blame History

/***
This file is part of systemd.
Copyright (C) 2014 Axis Communications AB. All rights reserved.
Copyright (C) 2015 Tom Gundersen
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 <arpa/inet.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "sd-ipv4acd.h"
#include "alloc-util.h"
#include "arp-util.h"
#include "fd-util.h"
#include "in-addr-util.h"
#include "list.h"
#include "random-util.h"
#include "refcnt.h"
#include "siphash24.h"
#include "util.h"
/* Constants from the RFC */
#define PROBE_WAIT 1
#define PROBE_NUM 3
#define PROBE_MIN 1
#define PROBE_MAX 2
#define ANNOUNCE_WAIT 2
#define ANNOUNCE_NUM 2
#define ANNOUNCE_INTERVAL 2
#define MAX_CONFLICTS 10
#define RATE_LIMIT_INTERVAL 60
#define DEFEND_INTERVAL 10
#define IPV4ACD_NETWORK 0xA9FE0000L
#define IPV4ACD_NETMASK 0xFFFF0000L
#define log_ipv4acd_full(ll, level, error, fmt, ...) log_internal(level, error, __FILE__, __LINE__, __func__, "ACD: " fmt, ##__VA_ARGS__)
#define log_ipv4acd_debug(ll, ...) log_ipv4acd_full(ll, LOG_DEBUG, 0, ##__VA_ARGS__)
#define log_ipv4acd_info(ll, ...) log_ipv4acd_full(ll, LOG_INFO, 0, ##__VA_ARGS__)
#define log_ipv4acd_notice(ll, ...) log_ipv4acd_full(ll, LOG_NOTICE, 0, ##__VA_ARGS__)
#define log_ipv4acd_warning(ll, ...) log_ipv4acd_full(ll, LOG_WARNING, 0, ##__VA_ARGS__)
#define log_ipv4acd_error(ll, ...) log_ipv4acd_full(ll, LOG_ERR, 0, ##__VA_ARGS__)
#define log_ipv4acd_debug_errno(ll, error, ...) log_ipv4acd_full(ll, LOG_DEBUG, error, ##__VA_ARGS__)
#define log_ipv4acd_info_errno(ll, error, ...) log_ipv4acd_full(ll, LOG_INFO, error, ##__VA_ARGS__)
#define log_ipv4acd_notice_errno(ll, error, ...) log_ipv4acd_full(ll, LOG_NOTICE, error, ##__VA_ARGS__)
#define log_ipv4acd_warning_errno(ll, error, ...) log_ipv4acd_full(ll, LOG_WARNING, error, ##__VA_ARGS__)
#define log_ipv4acd_error_errno(ll, error, ...) log_ipv4acd_full(ll, LOG_ERR, error, ##__VA_ARGS__)
typedef enum IPv4ACDState {
IPV4ACD_STATE_INIT,
IPV4ACD_STATE_WAITING_PROBE,
IPV4ACD_STATE_PROBING,
IPV4ACD_STATE_WAITING_ANNOUNCE,
IPV4ACD_STATE_ANNOUNCING,
IPV4ACD_STATE_RUNNING,
_IPV4ACD_STATE_MAX,
_IPV4ACD_STATE_INVALID = -1
} IPv4ACDState;
struct sd_ipv4acd {
RefCount n_ref;
IPv4ACDState state;
int index;
int fd;
int iteration;
int conflict;
sd_event_source *receive_message;
sd_event_source *timer;
usec_t defend_window;
be32_t address;
/* External */
struct ether_addr mac_addr;
sd_event *event;
int event_priority;
sd_ipv4acd_callback_t cb;
void* userdata;
};
sd_ipv4acd *sd_ipv4acd_ref(sd_ipv4acd *ll) {
if (ll)
assert_se(REFCNT_INC(ll->n_ref) >= 2);
return ll;
}
sd_ipv4acd *sd_ipv4acd_unref(sd_ipv4acd *ll) {
if (!ll || REFCNT_DEC(ll->n_ref) > 0)
return NULL;
ll->receive_message = sd_event_source_unref(ll->receive_message);
ll->fd = safe_close(ll->fd);
ll->timer = sd_event_source_unref(ll->timer);
sd_ipv4acd_detach_event(ll);
free(ll);
return NULL;
}
int sd_ipv4acd_new(sd_ipv4acd **ret) {
_cleanup_(sd_ipv4acd_unrefp) sd_ipv4acd *ll = NULL;
assert_return(ret, -EINVAL);
ll = new0(sd_ipv4acd, 1);
if (!ll)
return -ENOMEM;
ll->n_ref = REFCNT_INIT;
ll->state = IPV4ACD_STATE_INIT;
ll->index = -1;
ll->fd = -1;
*ret = ll;
ll = NULL;
return 0;
}
static void ipv4acd_set_state(sd_ipv4acd *ll, IPv4ACDState st, bool reset_counter) {
assert(ll);
assert(st < _IPV4ACD_STATE_MAX);
if (st == ll->state && !reset_counter)
ll->iteration++;
else {
ll->state = st;
ll->iteration = 0;
}
}
static void ipv4acd_client_notify(sd_ipv4acd *ll, int event) {
assert(ll);
if (ll->cb)
ll->cb(ll, event, ll->userdata);
}
static void ipv4acd_stop(sd_ipv4acd *ll) {
assert(ll);
ll->receive_message = sd_event_source_unref(ll->receive_message);
ll->fd = safe_close(ll->fd);
ll->timer = sd_event_source_unref(ll->timer);
log_ipv4acd_debug(ll, "STOPPED");
ipv4acd_set_state (ll, IPV4ACD_STATE_INIT, true);
}
int sd_ipv4acd_stop(sd_ipv4acd *ll) {
assert_return(ll, -EINVAL);
ipv4acd_stop(ll);
ipv4acd_client_notify(ll, SD_IPV4ACD_EVENT_STOP);
return 0;
}
static int ipv4acd_on_timeout(sd_event_source *s, uint64_t usec, void *userdata);
static int ipv4acd_set_next_wakeup(sd_ipv4acd *ll, int sec, int random_sec) {
_cleanup_(sd_event_source_unrefp) sd_event_source *timer = NULL;
usec_t next_timeout;
usec_t time_now;
int r;
assert(sec >= 0);
assert(random_sec >= 0);
assert(ll);
next_timeout = sec * USEC_PER_SEC;
if (random_sec)
next_timeout += random_u32() % (random_sec * USEC_PER_SEC);
assert_se(sd_event_now(ll->event, clock_boottime_or_monotonic(), &time_now) >= 0);
r = sd_event_add_time(ll->event, &timer, clock_boottime_or_monotonic(),
time_now + next_timeout, 0, ipv4acd_on_timeout, ll);
if (r < 0)
return r;
r = sd_event_source_set_priority(timer, ll->event_priority);
if (r < 0)
return r;
r = sd_event_source_set_description(timer, "ipv4acd-timer");
if (r < 0)
return r;
ll->timer = sd_event_source_unref(ll->timer);
ll->timer = timer;
timer = NULL;
return 0;
}
static bool ipv4acd_arp_conflict(sd_ipv4acd *ll, struct ether_arp *arp) {
assert(ll);
assert(arp);
/* see the BPF */
if (memcmp(arp->arp_spa, &ll->address, sizeof(ll->address)) == 0)
return true;
/* the TPA matched instead of the SPA, this is not a conflict */
return false;
}
static int ipv4acd_on_timeout(sd_event_source *s, uint64_t usec, void *userdata) {
sd_ipv4acd *ll = userdata;
int r = 0;
assert(ll);
switch (ll->state) {
case IPV4ACD_STATE_INIT:
ipv4acd_set_state(ll, IPV4ACD_STATE_WAITING_PROBE, true);
if (ll->conflict >= MAX_CONFLICTS) {
log_ipv4acd_notice(ll, "Max conflicts reached, delaying by %us", RATE_LIMIT_INTERVAL);
r = ipv4acd_set_next_wakeup(ll, RATE_LIMIT_INTERVAL, PROBE_WAIT);
if (r < 0)
goto out;
ll->conflict = 0;
} else {
r = ipv4acd_set_next_wakeup(ll, 0, PROBE_WAIT);
if (r < 0)
goto out;
}
break;
case IPV4ACD_STATE_WAITING_PROBE:
case IPV4ACD_STATE_PROBING:
/* Send a probe */
r = arp_send_probe(ll->fd, ll->index, ll->address, &ll->mac_addr);
if (r < 0) {
log_ipv4acd_error_errno(ll, r, "Failed to send ARP probe: %m");
goto out;
} else {
_cleanup_free_ char *address = NULL;
union in_addr_union addr = { .in.s_addr = ll->address };
r = in_addr_to_string(AF_INET, &addr, &address);
if (r >= 0)
log_ipv4acd_debug(ll, "Probing %s", address);
}
if (ll->iteration < PROBE_NUM - 2) {
ipv4acd_set_state(ll, IPV4ACD_STATE_PROBING, false);
r = ipv4acd_set_next_wakeup(ll, PROBE_MIN, (PROBE_MAX-PROBE_MIN));
if (r < 0)
goto out;
} else {
ipv4acd_set_state(ll, IPV4ACD_STATE_WAITING_ANNOUNCE, true);
r = ipv4acd_set_next_wakeup(ll, ANNOUNCE_WAIT, 0);
if (r < 0)
goto out;
}
break;
case IPV4ACD_STATE_ANNOUNCING:
if (ll->iteration >= ANNOUNCE_NUM - 1) {
ipv4acd_set_state(ll, IPV4ACD_STATE_RUNNING, false);
break;
}
case IPV4ACD_STATE_WAITING_ANNOUNCE:
/* Send announcement packet */
r = arp_send_announcement(ll->fd, ll->index, ll->address, &ll->mac_addr);
if (r < 0) {
log_ipv4acd_error_errno(ll, r, "Failed to send ARP announcement: %m");
goto out;
} else
log_ipv4acd_debug(ll, "ANNOUNCE");
ipv4acd_set_state(ll, IPV4ACD_STATE_ANNOUNCING, false);
r = ipv4acd_set_next_wakeup(ll, ANNOUNCE_INTERVAL, 0);
if (r < 0)
goto out;
if (ll->iteration == 0) {
ll->conflict = 0;
ipv4acd_client_notify(ll, SD_IPV4ACD_EVENT_BIND);
}
break;
default:
assert_not_reached("Invalid state.");
}
out:
if (r < 0)
sd_ipv4acd_stop(ll);
return 1;
}
static void ipv4acd_on_conflict(sd_ipv4acd *ll) {
_cleanup_free_ char *address = NULL;
union in_addr_union addr = { .in.s_addr = ll->address };
int r;
assert(ll);
ll->conflict++;
r = in_addr_to_string(AF_INET, &addr, &address);
if (r >= 0)
log_ipv4acd_debug(ll, "Conflict on %s (%u)", address, ll->conflict);
ipv4acd_stop(ll);
ipv4acd_client_notify(ll, SD_IPV4ACD_EVENT_CONFLICT);
}
static int ipv4acd_on_packet(sd_event_source *s, int fd,
uint32_t revents, void *userdata) {
sd_ipv4acd *ll = userdata;
struct ether_arp packet;
int r;
assert(ll);
assert(fd >= 0);
r = read(fd, &packet, sizeof(struct ether_arp));
if (r < (int) sizeof(struct ether_arp))
goto out;
switch (ll->state) {
case IPV4ACD_STATE_ANNOUNCING:
case IPV4ACD_STATE_RUNNING:
if (ipv4acd_arp_conflict(ll, &packet)) {
usec_t ts;
assert_se(sd_event_now(ll->event, clock_boottime_or_monotonic(), &ts) >= 0);
/* Defend address */
if (ts > ll->defend_window) {
ll->defend_window = ts + DEFEND_INTERVAL * USEC_PER_SEC;
r = arp_send_announcement(ll->fd, ll->index, ll->address, &ll->mac_addr);
if (r < 0) {
log_ipv4acd_error_errno(ll, r, "Failed to send ARP announcement: %m");
goto out;
} else
log_ipv4acd_debug(ll, "DEFEND");
} else
ipv4acd_on_conflict(ll);
}
break;
case IPV4ACD_STATE_WAITING_PROBE:
case IPV4ACD_STATE_PROBING:
case IPV4ACD_STATE_WAITING_ANNOUNCE:
/* BPF ensures this packet indicates a conflict */
ipv4acd_on_conflict(ll);
break;
default:
assert_not_reached("Invalid state.");
}
out:
if (r < 0)
sd_ipv4acd_stop(ll);
return 1;
}
int sd_ipv4acd_set_index(sd_ipv4acd *ll, int interface_index) {
assert_return(ll, -EINVAL);
assert_return(interface_index > 0, -EINVAL);
assert_return(ll->state == IPV4ACD_STATE_INIT, -EBUSY);
ll->index = interface_index;
return 0;
}
int sd_ipv4acd_set_mac(sd_ipv4acd *ll, const struct ether_addr *addr) {
assert_return(ll, -EINVAL);
assert_return(addr, -EINVAL);
assert_return(ll->state == IPV4ACD_STATE_INIT, -EBUSY);
memcpy(&ll->mac_addr, addr, ETH_ALEN);
return 0;
}
int sd_ipv4acd_detach_event(sd_ipv4acd *ll) {
assert_return(ll, -EINVAL);
ll->event = sd_event_unref(ll->event);
return 0;
}
int sd_ipv4acd_attach_event(sd_ipv4acd *ll, sd_event *event, int64_t priority) {
int r;
assert_return(ll, -EINVAL);
assert_return(!ll->event, -EBUSY);
if (event)
ll->event = sd_event_ref(event);
else {
r = sd_event_default(&ll->event);
if (r < 0)
return r;
}
ll->event_priority = priority;
return 0;
}
int sd_ipv4acd_set_callback(sd_ipv4acd *ll, sd_ipv4acd_callback_t cb, void *userdata) {
assert_return(ll, -EINVAL);
ll->cb = cb;
ll->userdata = userdata;
return 0;
}
int sd_ipv4acd_set_address(sd_ipv4acd *ll, const struct in_addr *address) {
assert_return(ll, -EINVAL);
assert_return(address, -EINVAL);
assert_return(ll->state == IPV4ACD_STATE_INIT, -EBUSY);
ll->address = address->s_addr;
return 0;
}
int sd_ipv4acd_is_running(sd_ipv4acd *ll) {
assert_return(ll, false);
return ll->state != IPV4ACD_STATE_INIT;
}
static bool ether_addr_is_nul(const struct ether_addr *addr) {
const struct ether_addr nul_addr = {};
assert(addr);
return memcmp(addr, &nul_addr, sizeof(struct ether_addr)) == 0;
}
#define HASH_KEY SD_ID128_MAKE(df,04,22,98,3f,ad,14,52,f9,87,2e,d1,9c,70,e2,f2)
int sd_ipv4acd_start(sd_ipv4acd *ll) {
int r;
assert_return(ll, -EINVAL);
assert_return(ll->event, -EINVAL);
assert_return(ll->index > 0, -EINVAL);
assert_return(ll->address != 0, -EINVAL);
assert_return(!ether_addr_is_nul(&ll->mac_addr), -EINVAL);
assert_return(ll->state == IPV4ACD_STATE_INIT, -EBUSY);
ll->defend_window = 0;
r = arp_network_bind_raw_socket(ll->index, ll->address, &ll->mac_addr);
if (r < 0)
goto out;
ll->fd = safe_close(ll->fd);
ll->fd = r;
r = sd_event_add_io(ll->event, &ll->receive_message, ll->fd,
EPOLLIN, ipv4acd_on_packet, ll);
if (r < 0)
goto out;
r = sd_event_source_set_priority(ll->receive_message, ll->event_priority);
if (r < 0)
goto out;
r = sd_event_source_set_description(ll->receive_message, "ipv4acd-receive-message");
if (r < 0)
goto out;
r = ipv4acd_set_next_wakeup(ll, 0, 0);
if (r < 0)
goto out;
out:
if (r < 0) {
ipv4acd_stop(ll);
return r;
}
return 0;
}
Reference in New Issue View Git Blame Copy Permalink