aba496a58a
Currently when both ipv4ll and dhcp are enabled, ipv4ll address (if one has been claimed) is removed when dhcp address is aquired. This is not the best thing to do since there might be clients unaware of the removal trying to communicate. This patch provides a smooth transition between ipv4ll and dhcp. If ipv4ll address was claimed [1] before dhcp, address is marked as deprecated. Deprecated address is still a valid address and packets can be received on it but address cannot be selected as a source address. If dhcp lease cannot be extended, then ipv4ll address is marked as valid again. [1] If there is no collision, claiming IPv4LL takes between 4 to 7 seconds.
594 lines
17 KiB
C
594 lines
17 KiB
C
/***
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This file is part of systemd.
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Copyright (C) 2014 Axis Communications AB. All rights reserved.
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <stdlib.h>
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#include <errno.h>
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#include <string.h>
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#include <stdio.h>
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#include <arpa/inet.h>
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#include "util.h"
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#include "siphash24.h"
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#include "list.h"
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#include "ipv4ll-internal.h"
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#include "sd-ipv4ll.h"
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/* Constants from the RFC */
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#define PROBE_WAIT 1
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#define PROBE_NUM 3
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#define PROBE_MIN 1
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#define PROBE_MAX 2
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#define ANNOUNCE_WAIT 2
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#define ANNOUNCE_NUM 2
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#define ANNOUNCE_INTERVAL 2
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#define MAX_CONFLICTS 10
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#define RATE_LIMIT_INTERVAL 60
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#define DEFEND_INTERVAL 10
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#define IPV4LL_NETWORK 0xA9FE0000L
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#define IPV4LL_NETMASK 0xFFFF0000L
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typedef enum IPv4LLTrigger{
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IPV4LL_TRIGGER_NULL,
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IPV4LL_TRIGGER_PACKET,
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IPV4LL_TRIGGER_TIMEOUT,
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_IPV4LL_TRIGGER_MAX,
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_IPV4LL_TRIGGER_INVALID = -1
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} IPv4LLTrigger;
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typedef enum IPv4LLState {
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IPV4LL_STATE_INIT,
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IPV4LL_STATE_WAITING_PROBE,
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IPV4LL_STATE_PROBING,
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IPV4LL_STATE_WAITING_ANNOUNCE,
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IPV4LL_STATE_ANNOUNCING,
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IPV4LL_STATE_RUNNING,
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_IPV4LL_STATE_MAX,
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_IPV4LL_STATE_INVALID = -1
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} IPv4LLState;
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struct sd_ipv4ll {
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IPv4LLState state;
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int index;
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int fd;
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union sockaddr_union link;
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int iteration;
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int conflict;
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sd_event_source *receive_message;
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sd_event_source *timer;
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usec_t next_wakeup;
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usec_t defend_window;
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int next_wakeup_valid;
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be32_t address;
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struct random_data *random_data;
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char *random_data_state;
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/* External */
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be32_t claimed_address;
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struct ether_addr mac_addr;
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sd_event *event;
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int event_priority;
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sd_ipv4ll_cb_t cb;
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void* userdata;
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};
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static void ipv4ll_run_state_machine(sd_ipv4ll *ll, IPv4LLTrigger trigger, void *trigger_data);
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static void ipv4ll_set_state(sd_ipv4ll *ll, IPv4LLState st, int reset_counter) {
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assert(ll);
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assert(st < _IPV4LL_STATE_MAX);
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if (st == ll->state && !reset_counter) {
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ll->iteration++;
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} else {
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ll->state = st;
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ll->iteration = 0;
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}
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}
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static int ipv4ll_client_notify(sd_ipv4ll *ll, int event) {
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assert(ll);
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if (ll->cb)
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ll->cb(ll, event, ll->userdata);
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return 0;
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}
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static int ipv4ll_stop(sd_ipv4ll *ll, int event) {
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assert(ll);
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ll->receive_message = sd_event_source_unref(ll->receive_message);
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ll->fd = safe_close(ll->fd);
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ll->timer = sd_event_source_unref(ll->timer);
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ipv4ll_client_notify(ll, event);
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ll->claimed_address = 0;
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ipv4ll_set_state (ll, IPV4LL_STATE_INIT, 1);
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log_ipv4ll(ll, "STOPPED");
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return 0;
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}
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static int ipv4ll_pick_address(sd_ipv4ll *ll, be32_t *address) {
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be32_t addr;
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int r;
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int32_t random;
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assert(ll);
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assert(address);
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assert(ll->random_data);
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do {
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r = random_r(ll->random_data, &random);
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if (r < 0)
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return r;
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addr = htonl((random & 0x0000FFFF) | IPV4LL_NETWORK);
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} while (addr == ll->address ||
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(ntohl(addr) & IPV4LL_NETMASK) != IPV4LL_NETWORK ||
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(ntohl(addr) & 0x0000FF00) == 0x0000 ||
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(ntohl(addr) & 0x0000FF00) == 0xFF00);
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*address = addr;
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return 0;
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}
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static int ipv4ll_timer(sd_event_source *s, uint64_t usec, void *userdata) {
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sd_ipv4ll *ll = (sd_ipv4ll*)userdata;
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assert(ll);
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ll->next_wakeup_valid = 0;
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ipv4ll_run_state_machine(ll, IPV4LL_TRIGGER_TIMEOUT, NULL);
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return 0;
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}
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static void ipv4ll_set_next_wakeup(sd_ipv4ll *ll, int sec, int random_sec) {
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usec_t next_timeout = 0;
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usec_t time_now = 0;
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assert(sec >= 0);
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assert(random_sec >= 0);
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assert(ll);
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next_timeout = sec * USEC_PER_SEC;
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if (random_sec)
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next_timeout += random_u32() % (random_sec * USEC_PER_SEC);
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if (sd_event_now(ll->event, CLOCK_MONOTONIC, &time_now) < 0)
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time_now = now(CLOCK_MONOTONIC);
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ll->next_wakeup = time_now + next_timeout;
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ll->next_wakeup_valid = 1;
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}
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static bool ipv4ll_arp_conflict (sd_ipv4ll *ll, struct ether_arp *arp) {
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assert(ll);
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assert(arp);
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if (memcmp(arp->arp_spa, &ll->address, sizeof(ll->address)) == 0 &&
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memcmp(arp->arp_sha, &ll->mac_addr, ETH_ALEN) != 0)
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return true;
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return false;
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}
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static bool ipv4ll_arp_probe_conflict (sd_ipv4ll *ll, struct ether_arp *arp) {
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assert(ll);
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assert(arp);
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if (ipv4ll_arp_conflict(ll, arp))
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return true;
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if (memcmp(arp->arp_tpa, &ll->address, sizeof(ll->address)) == 0 &&
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memcmp(arp->arp_sha, &ll->mac_addr, ETH_ALEN))
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return true;
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return false;
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}
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static void ipv4ll_run_state_machine(sd_ipv4ll *ll, IPv4LLTrigger trigger, void *trigger_data) {
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struct ether_arp out_packet;
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int out_packet_ready = 0;
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int r = 0;
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assert(ll);
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assert(trigger < _IPV4LL_TRIGGER_MAX);
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if (ll->state == IPV4LL_STATE_INIT) {
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log_ipv4ll(ll, "PROBE");
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ipv4ll_set_state(ll, IPV4LL_STATE_WAITING_PROBE, 1);
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ipv4ll_set_next_wakeup(ll, 0, PROBE_WAIT);
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} else if ((ll->state == IPV4LL_STATE_WAITING_PROBE && trigger == IPV4LL_TRIGGER_TIMEOUT) ||
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(ll->state == IPV4LL_STATE_PROBING && trigger == IPV4LL_TRIGGER_TIMEOUT && ll->iteration < PROBE_NUM-2)) {
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/* Send a probe */
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arp_packet_probe(&out_packet, ll->address, &ll->mac_addr);
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out_packet_ready = 1;
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ipv4ll_set_state(ll, IPV4LL_STATE_PROBING, 0);
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ipv4ll_set_next_wakeup(ll, PROBE_MIN, (PROBE_MAX-PROBE_MIN));
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} else if (ll->state == IPV4LL_STATE_PROBING && trigger == IPV4LL_TRIGGER_TIMEOUT && ll->iteration >= PROBE_NUM-2) {
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/* Send the last probe */
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arp_packet_probe(&out_packet, ll->address, &ll->mac_addr);
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out_packet_ready = 1;
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ipv4ll_set_state(ll, IPV4LL_STATE_WAITING_ANNOUNCE, 1);
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ipv4ll_set_next_wakeup(ll, ANNOUNCE_WAIT, 0);
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} else if ((ll->state == IPV4LL_STATE_WAITING_ANNOUNCE && trigger == IPV4LL_TRIGGER_TIMEOUT) ||
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(ll->state == IPV4LL_STATE_ANNOUNCING && trigger == IPV4LL_TRIGGER_TIMEOUT && ll->iteration < ANNOUNCE_NUM-1)) {
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/* Send announcement packet */
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arp_packet_announcement(&out_packet, ll->address, &ll->mac_addr);
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out_packet_ready = 1;
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ipv4ll_set_state(ll, IPV4LL_STATE_ANNOUNCING, 0);
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ipv4ll_set_next_wakeup(ll, ANNOUNCE_INTERVAL, 0);
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if (ll->iteration == 0) {
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log_ipv4ll(ll, "ANNOUNCE");
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ll->claimed_address = ll->address;
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r = ipv4ll_client_notify(ll, IPV4LL_EVENT_BIND);
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ll->conflict = 0;
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}
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} else if ((ll->state == IPV4LL_STATE_ANNOUNCING && trigger == IPV4LL_TRIGGER_TIMEOUT &&
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ll->iteration >= ANNOUNCE_NUM-1)) {
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ipv4ll_set_state(ll, IPV4LL_STATE_RUNNING, 0);
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ll->next_wakeup_valid = 0;
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} else if (trigger == IPV4LL_TRIGGER_PACKET) {
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int conflicted = 0;
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usec_t time_now;
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struct ether_arp* in_packet = (struct ether_arp*)trigger_data;
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assert(in_packet);
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if (IN_SET(ll->state, IPV4LL_STATE_ANNOUNCING, IPV4LL_STATE_RUNNING)) {
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if (ipv4ll_arp_conflict(ll, in_packet)) {
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r = sd_event_now(ll->event, CLOCK_MONOTONIC, &time_now);
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if (r < 0)
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goto out;
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/* Defend address */
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if (time_now > ll->defend_window) {
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ll->defend_window = time_now + DEFEND_INTERVAL * USEC_PER_SEC;
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arp_packet_announcement(&out_packet, ll->address, &ll->mac_addr);
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out_packet_ready = 1;
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} else
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conflicted = 1;
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}
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} else if (IN_SET(ll->state, IPV4LL_STATE_WAITING_PROBE,
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IPV4LL_STATE_PROBING,
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IPV4LL_STATE_WAITING_ANNOUNCE)) {
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conflicted = ipv4ll_arp_probe_conflict(ll, in_packet);
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}
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if (conflicted) {
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log_ipv4ll(ll, "CONFLICT");
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r = ipv4ll_client_notify(ll, IPV4LL_EVENT_CONFLICT);
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ll->claimed_address = 0;
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/* Pick a new address */
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r = ipv4ll_pick_address(ll, &ll->address);
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if (r < 0)
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goto out;
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ll->conflict++;
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ll->defend_window = 0;
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ipv4ll_set_state(ll, IPV4LL_STATE_WAITING_PROBE, 1);
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if (ll->conflict >= MAX_CONFLICTS) {
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log_ipv4ll(ll, "MAX_CONFLICTS");
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ipv4ll_set_next_wakeup(ll, RATE_LIMIT_INTERVAL, PROBE_WAIT);
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} else
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ipv4ll_set_next_wakeup(ll, 0, PROBE_WAIT);
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}
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}
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if (out_packet_ready) {
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r = arp_network_send_raw_socket(ll->fd, &ll->link, &out_packet);
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if (r < 0) {
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log_ipv4ll(ll, "failed to send arp packet out");
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goto out;
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}
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}
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if (ll->next_wakeup_valid) {
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ll->timer = sd_event_source_unref(ll->timer);
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r = sd_event_add_time(ll->event, &ll->timer, CLOCK_MONOTONIC,
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ll->next_wakeup, 0, ipv4ll_timer, ll);
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if (r < 0)
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goto out;
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r = sd_event_source_set_priority(ll->timer, ll->event_priority);
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if (r < 0)
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goto out;
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}
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out:
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if (r < 0)
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ipv4ll_stop(ll, r);
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}
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static int ipv4ll_receive_message(sd_event_source *s, int fd,
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uint32_t revents, void *userdata) {
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int r;
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struct ether_arp arp;
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sd_ipv4ll *ll = (sd_ipv4ll*)userdata;
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assert(ll);
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r = read(fd, &arp, sizeof(struct ether_arp));
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if (r < (int) sizeof(struct ether_arp))
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return 0;
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r = arp_packet_verify_headers(&arp);
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if (r < 0)
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return 0;
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ipv4ll_run_state_machine(ll, IPV4LL_TRIGGER_PACKET, &arp);
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return 0;
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}
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int sd_ipv4ll_set_index(sd_ipv4ll *ll, int interface_index) {
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assert_return(ll, -EINVAL);
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assert_return(interface_index >= -1, -EINVAL);
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assert_return(ll->state == IPV4LL_STATE_INIT, -EBUSY);
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ll->index = interface_index;
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return 0;
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}
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int sd_ipv4ll_set_mac(sd_ipv4ll *ll, const struct ether_addr *addr) {
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bool need_restart = false;
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assert_return(ll, -EINVAL);
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assert_return(addr, -EINVAL);
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if (memcmp(&ll->mac_addr, addr, ETH_ALEN) == 0)
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return 0;
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if (ll->state != IPV4LL_STATE_INIT) {
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log_ipv4ll(ll, "Changing MAC address on running IPv4LL "
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"client, restarting");
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sd_ipv4ll_stop(ll);
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need_restart = true;
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}
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memcpy(&ll->mac_addr, addr, ETH_ALEN);
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if (need_restart)
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sd_ipv4ll_start(ll);
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return 0;
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}
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int sd_ipv4ll_detach_event(sd_ipv4ll *ll) {
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assert_return(ll, -EINVAL);
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ll->event = sd_event_unref(ll->event);
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return 0;
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}
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int sd_ipv4ll_attach_event(sd_ipv4ll *ll, sd_event *event, int priority) {
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int r;
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assert_return(ll, -EINVAL);
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assert_return(!ll->event, -EBUSY);
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if (event)
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ll->event = sd_event_ref(event);
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else {
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r = sd_event_default(&ll->event);
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if (r < 0) {
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ipv4ll_stop(ll, IPV4LL_EVENT_STOP);
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return r;
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}
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}
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ll->event_priority = priority;
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return 0;
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}
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int sd_ipv4ll_set_callback(sd_ipv4ll *ll, sd_ipv4ll_cb_t cb, void *userdata) {
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assert_return(ll, -EINVAL);
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ll->cb = cb;
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ll->userdata = userdata;
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return 0;
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}
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int sd_ipv4ll_get_address(sd_ipv4ll *ll, struct in_addr *address){
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assert_return(ll, -EINVAL);
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assert_return(address, -EINVAL);
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if (ll->claimed_address == 0) {
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return -ENOENT;
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}
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address->s_addr = ll->claimed_address;
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return 0;
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}
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int sd_ipv4ll_set_address_seed (sd_ipv4ll *ll, uint8_t seed[8]) {
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unsigned int entropy = *seed;
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int r;
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assert_return(ll, -EINVAL);
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free(ll->random_data);
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free(ll->random_data_state);
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ll->random_data = new0(struct random_data, 1);
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ll->random_data_state = new0(char, 128);
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if (!ll->random_data || !ll->random_data_state) {
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r = -ENOMEM;
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goto error;
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}
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r = initstate_r((unsigned int)entropy, ll->random_data_state, 128, ll->random_data);
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if (r < 0)
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goto error;
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error:
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if (r < 0){
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free(ll->random_data);
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free(ll->random_data_state);
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ll->random_data = NULL;
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ll->random_data_state = NULL;
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}
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return r;
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}
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bool sd_ipv4ll_is_running(sd_ipv4ll *ll) {
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assert_return(ll, -EINVAL);
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return ll->state != IPV4LL_STATE_INIT;
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}
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#define HASH_KEY SD_ID128_MAKE(df,04,22,98,3f,ad,14,52,f9,87,2e,d1,9c,70,e2,f2)
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int sd_ipv4ll_start (sd_ipv4ll *ll) {
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int r;
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assert_return(ll, -EINVAL);
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assert_return(ll->event, -EINVAL);
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assert_return(ll->index > 0, -EINVAL);
|
|
assert_return(ll->state == IPV4LL_STATE_INIT, -EBUSY);
|
|
|
|
r = arp_network_bind_raw_socket(ll->index, &ll->link);
|
|
|
|
if (r < 0)
|
|
goto out;
|
|
|
|
ll->fd = r;
|
|
ll->conflict = 0;
|
|
ll->defend_window = 0;
|
|
ll->claimed_address = 0;
|
|
|
|
if (!ll->random_data) {
|
|
uint8_t seed[8];
|
|
|
|
/* Fallback to mac */
|
|
siphash24(seed, &ll->mac_addr.ether_addr_octet,
|
|
ETH_ALEN, HASH_KEY.bytes);
|
|
|
|
r = sd_ipv4ll_set_address_seed(ll, seed);
|
|
if (r < 0)
|
|
goto out;
|
|
}
|
|
|
|
if (ll->address == 0) {
|
|
r = ipv4ll_pick_address(ll, &ll->address);
|
|
if (r < 0)
|
|
goto out;
|
|
}
|
|
|
|
ipv4ll_set_state (ll, IPV4LL_STATE_INIT, 1);
|
|
|
|
r = sd_event_add_io(ll->event, &ll->receive_message, ll->fd,
|
|
EPOLLIN, ipv4ll_receive_message, 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_add_time(ll->event,
|
|
&ll->timer,
|
|
CLOCK_MONOTONIC,
|
|
now(CLOCK_MONOTONIC), 0,
|
|
ipv4ll_timer, ll);
|
|
|
|
if (r < 0)
|
|
goto out;
|
|
|
|
r = sd_event_source_set_priority(ll->timer, ll->event_priority);
|
|
|
|
out:
|
|
if (r < 0)
|
|
ipv4ll_stop(ll, IPV4LL_EVENT_STOP);
|
|
|
|
return 0;
|
|
}
|
|
|
|
int sd_ipv4ll_stop(sd_ipv4ll *ll) {
|
|
return ipv4ll_stop(ll, IPV4LL_EVENT_STOP);
|
|
}
|
|
|
|
void sd_ipv4ll_free (sd_ipv4ll *ll) {
|
|
if (!ll)
|
|
return;
|
|
|
|
sd_ipv4ll_stop(ll);
|
|
sd_ipv4ll_detach_event(ll);
|
|
|
|
free(ll->random_data);
|
|
free(ll->random_data_state);
|
|
free(ll);
|
|
}
|
|
|
|
DEFINE_TRIVIAL_CLEANUP_FUNC(sd_ipv4ll*, sd_ipv4ll_free);
|
|
#define _cleanup_ipv4ll_free_ _cleanup_(sd_ipv4ll_freep)
|
|
|
|
int sd_ipv4ll_new(sd_ipv4ll **ret) {
|
|
_cleanup_ipv4ll_free_ sd_ipv4ll *ll = NULL;
|
|
|
|
assert_return(ret, -EINVAL);
|
|
|
|
ll = new0(sd_ipv4ll, 1);
|
|
if (!ll)
|
|
return -ENOMEM;
|
|
|
|
ll->state = IPV4LL_STATE_INIT;
|
|
ll->index = -1;
|
|
ll->fd = -1;
|
|
|
|
*ret = ll;
|
|
ll = NULL;
|
|
|
|
return 0;
|
|
}
|