--- /dev/null
+/***
+ This file is part of systemd.
+
+ Copyright (C) 2014 Axis Communications AB. 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 <stdlib.h>
+#include <errno.h>
+#include <string.h>
+#include <stdio.h>
+#include <arpa/inet.h>
+
+#include "util.h"
+#include "list.h"
+
+#include "ipv4ll-internal.h"
+#include "sd-ipv4ll.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 IPV4LL_NETWORK 0xA9FE0000L
+#define IPV4LL_NETMASK 0xFFFF0000L
+
+typedef enum IPv4LLTrigger{
+ IPV4LL_TRIGGER_NULL,
+ IPV4LL_TRIGGER_PACKET,
+ IPV4LL_TRIGGER_TIMEOUT,
+ _IPV4LL_TRIGGER_MAX,
+ _IPV4LL_TRIGGER_INVALID = -1
+} IPv4LLTrigger;
+
+typedef enum IPv4LLState {
+ IPV4LL_STATE_INIT,
+ IPV4LL_STATE_WAITING_PROBE,
+ IPV4LL_STATE_PROBING,
+ IPV4LL_STATE_WAITING_ANNOUNCE,
+ IPV4LL_STATE_ANNOUNCING,
+ IPV4LL_STATE_RUNNING,
+ _IPV4LL_STATE_MAX,
+ _IPV4LL_STATE_INVALID = -1
+} IPv4LLState;
+
+struct sd_ipv4ll {
+ IPv4LLState state;
+ int index;
+ int fd;
+ union sockaddr_union link;
+ int iteration;
+ int conflict;
+ sd_event_source *receive_message;
+ sd_event_source *timer;
+ usec_t next_wakeup;
+ usec_t defend_window;
+ int next_wakeup_valid;
+ be32_t address;
+ /* External */
+ be32_t claimed_address;
+ struct ether_addr mac_addr;
+ sd_event *event;
+ int event_priority;
+ sd_ipv4ll_cb_t cb;
+ void* userdata;
+};
+
+static void ipv4ll_run_state_machine(sd_ipv4ll *ll, IPv4LLTrigger trigger, void *trigger_data);
+
+static void ipv4ll_set_state(sd_ipv4ll *ll, IPv4LLState st, int reset_counter) {
+
+ assert(ll);
+ assert(st < _IPV4LL_STATE_MAX);
+
+ if (st == ll->state && !reset_counter) {
+ ll->iteration++;
+ } else {
+ ll->state = st;
+ ll->iteration = 0;
+ }
+}
+
+static int ipv4ll_client_notify(sd_ipv4ll *ll, int event) {
+ assert(ll);
+
+ if (ll->cb)
+ ll->cb(ll, event, ll->userdata);
+
+ return 0;
+}
+
+static int ipv4ll_stop(sd_ipv4ll *ll, int event) {
+ assert(ll);
+
+ ll->receive_message = sd_event_source_unref(ll->receive_message);
+ if (ll->fd >= 0)
+ close_nointr_nofail(ll->fd);
+ ll->fd = -1;
+
+ ll->timer = sd_event_source_unref(ll->timer);
+
+ ipv4ll_client_notify(ll, event);
+
+ ll->claimed_address = 0;
+
+ ipv4ll_set_state (ll, IPV4LL_STATE_INIT, 1);
+
+ log_ipv4ll(ll, "STOPPED");
+
+ return 0;
+}
+
+static be32_t ipv4ll_pick_address(sd_ipv4ll *ll) {
+ be32_t addr;
+
+ assert(ll);
+
+ if (ll->address) {
+ do {
+ uint32_t r = random_u32() & 0x0000FFFF;
+ addr = htonl(IPV4LL_NETWORK | r);
+ } while (addr == ll->address ||
+ (ntohl(addr) & IPV4LL_NETMASK) != IPV4LL_NETWORK ||
+ (ntohl(addr) & 0x0000FF00) == 0x0000 ||
+ (ntohl(addr) & 0x0000FF00) == 0xFF00);
+ } else {
+ uint32_t a = 1;
+ int i;
+
+ for (i = 0; i < ETH_ALEN; i++)
+ a += ll->mac_addr.ether_addr_octet[i]*i;
+ a = (a % 0xFE00) + 0x0100;
+ addr = htonl(IPV4LL_NETWORK | (uint32_t) a);
+ }
+
+ return addr;
+}
+
+static int ipv4ll_timer(sd_event_source *s, uint64_t usec, void *userdata) {
+ sd_ipv4ll *ll = (sd_ipv4ll*)userdata;
+
+ assert(ll);
+
+ ll->next_wakeup_valid = 0;
+ ipv4ll_run_state_machine(ll, IPV4LL_TRIGGER_TIMEOUT, NULL);
+
+ return 0;
+}
+
+static void ipv4ll_set_next_wakeup (sd_ipv4ll *ll, int sec, int random_sec) {
+ usec_t next_timeout = 0;
+ usec_t time_now = 0;
+
+ 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);
+
+ if (sd_event_get_now_monotonic(ll->event, &time_now) < 0)
+ time_now = now(CLOCK_MONOTONIC);
+
+ ll->next_wakeup = time_now + next_timeout;
+ ll->next_wakeup_valid = 1;
+}
+
+static bool ipv4ll_arp_conflict (sd_ipv4ll *ll, struct ether_arp *arp) {
+ assert(ll);
+ assert(arp);
+
+ if (memcmp(arp->arp_spa, &ll->address, sizeof(ll->address)) == 0 &&
+ memcmp(arp->arp_sha, &ll->mac_addr, ETH_ALEN) != 0)
+ return true;
+
+ return false;
+}
+
+static bool ipv4ll_arp_probe_conflict (sd_ipv4ll *ll, struct ether_arp *arp) {
+ assert(ll);
+ assert(arp);
+
+ if (ipv4ll_arp_conflict(ll, arp))
+ return true;
+
+ if (memcmp(arp->arp_tpa, &ll->address, sizeof(ll->address)) == 0 &&
+ memcmp(arp->arp_sha, &ll->mac_addr, ETH_ALEN))
+ return true;
+
+ return false;
+}
+
+static void ipv4ll_run_state_machine(sd_ipv4ll *ll, IPv4LLTrigger trigger, void *trigger_data) {
+ struct ether_arp out_packet;
+ int out_packet_ready = 0;
+ int r = 0;
+
+ assert(ll);
+ assert(trigger < _IPV4LL_TRIGGER_MAX);
+
+ if (ll->state == IPV4LL_STATE_INIT) {
+
+ log_ipv4ll(ll, "PROBE");
+ ipv4ll_set_state(ll, IPV4LL_STATE_WAITING_PROBE, 1);
+ ipv4ll_set_next_wakeup(ll, 0, PROBE_WAIT);
+
+ } else if ((ll->state == IPV4LL_STATE_WAITING_PROBE && trigger == IPV4LL_TRIGGER_TIMEOUT) ||
+ (ll->state == IPV4LL_STATE_PROBING && trigger == IPV4LL_TRIGGER_TIMEOUT && ll->iteration < PROBE_NUM-2)) {
+
+ /* Send a probe */
+ arp_packet_probe(&out_packet, ll->address, &ll->mac_addr);
+ out_packet_ready = 1;
+ ipv4ll_set_state(ll, IPV4LL_STATE_PROBING, 0);
+
+ ipv4ll_set_next_wakeup(ll, PROBE_MIN, (PROBE_MAX-PROBE_MIN));
+
+ } else if (ll->state == IPV4LL_STATE_PROBING && trigger == IPV4LL_TRIGGER_TIMEOUT && ll->iteration >= PROBE_NUM-2) {
+
+ /* Send the last probe */
+ arp_packet_probe(&out_packet, ll->address, &ll->mac_addr);
+ out_packet_ready = 1;
+ ipv4ll_set_state(ll, IPV4LL_STATE_WAITING_ANNOUNCE, 1);
+
+ ipv4ll_set_next_wakeup(ll, ANNOUNCE_WAIT, 0);
+
+ } else if ((ll->state == IPV4LL_STATE_WAITING_ANNOUNCE && trigger == IPV4LL_TRIGGER_TIMEOUT) ||
+ (ll->state == IPV4LL_STATE_ANNOUNCING && trigger == IPV4LL_TRIGGER_TIMEOUT && ll->iteration < ANNOUNCE_NUM-1)) {
+
+ /* Send announcement packet */
+ arp_packet_announcement(&out_packet, ll->address, &ll->mac_addr);
+ out_packet_ready = 1;
+ ipv4ll_set_state(ll, IPV4LL_STATE_ANNOUNCING, 0);
+
+ ipv4ll_set_next_wakeup(ll, ANNOUNCE_INTERVAL, 0);
+
+ if (ll->iteration == 0) {
+ log_ipv4ll(ll, "ANNOUNCE");
+ ll->claimed_address = ll->address;
+ r = ipv4ll_client_notify(ll, IPV4LL_EVENT_BIND);
+ ll->conflict = 0;
+ }
+
+ } else if ((ll->state == IPV4LL_STATE_ANNOUNCING && trigger == IPV4LL_TRIGGER_TIMEOUT &&
+ ll->iteration >= ANNOUNCE_NUM-1)) {
+
+ ipv4ll_set_state(ll, IPV4LL_STATE_RUNNING, 0);
+ ll->next_wakeup_valid = 0;
+
+ } else if (trigger == IPV4LL_TRIGGER_PACKET) {
+
+ int conflicted = 0;
+ usec_t time_now;
+ struct ether_arp* in_packet = (struct ether_arp*)trigger_data;
+
+ assert(in_packet);
+
+ if (IN_SET(ll->state, IPV4LL_STATE_ANNOUNCING, IPV4LL_STATE_RUNNING)) {
+
+ if (ipv4ll_arp_conflict(ll, in_packet)) {
+
+ r = sd_event_get_now_monotonic(ll->event, &time_now);
+ if (r < 0)
+ goto out;
+
+ /* Defend address */
+ if (time_now > ll->defend_window) {
+ ll->defend_window = time_now + DEFEND_INTERVAL * USEC_PER_SEC;
+ arp_packet_announcement(&out_packet, ll->address, &ll->mac_addr);
+ out_packet_ready = 1;
+ } else
+ conflicted = 1;
+ }
+
+ } else if (IN_SET(ll->state, IPV4LL_STATE_WAITING_PROBE,
+ IPV4LL_STATE_PROBING,
+ IPV4LL_STATE_WAITING_ANNOUNCE)) {
+
+ conflicted = ipv4ll_arp_probe_conflict(ll, in_packet);
+ }
+
+ if (conflicted) {
+ log_ipv4ll(ll, "CONFLICT");
+ r = ipv4ll_client_notify(ll, IPV4LL_EVENT_CONFLICT);
+ ll->claimed_address = 0;
+
+ /* Pick a new address */
+ ll->address = ipv4ll_pick_address(ll);
+ ll->conflict++;
+ ll->defend_window = 0;
+ ipv4ll_set_state(ll, IPV4LL_STATE_WAITING_PROBE, 1);
+
+ if (ll->conflict >= MAX_CONFLICTS) {
+ log_ipv4ll(ll, "MAX_CONFLICTS");
+ ipv4ll_set_next_wakeup(ll, RATE_LIMIT_INTERVAL, PROBE_WAIT);
+ } else
+ ipv4ll_set_next_wakeup(ll, 0, PROBE_WAIT);
+
+ }
+ }
+
+ if (out_packet_ready) {
+ r = arp_network_send_raw_socket(ll->fd, &ll->link, &out_packet);
+ if (r < 0) {
+ log_ipv4ll(ll, "failed to send arp packet out");
+ goto out;
+ }
+ }
+
+ if (ll->next_wakeup_valid) {
+ ll->timer = sd_event_source_unref(ll->timer);
+ r = sd_event_add_monotonic(ll->event, &ll->timer,
+ ll->next_wakeup, 0, ipv4ll_timer, ll);
+ if (r < 0)
+ goto out;
+
+ r = sd_event_source_set_priority(ll->timer, ll->event_priority);
+ if (r < 0)
+ goto out;
+ }
+
+out:
+ if (r < 0)
+ ipv4ll_stop(ll, r);
+}
+
+static int ipv4ll_receive_message(sd_event_source *s, int fd,
+ uint32_t revents, void *userdata) {
+ int r;
+ struct ether_arp arp;
+ sd_ipv4ll *ll = (sd_ipv4ll*)userdata;
+
+ assert(ll);
+
+ r = read(fd, &arp, sizeof(struct ether_arp));
+ if (r < (int) sizeof(struct ether_arp))
+ return 0;
+
+ r = arp_packet_verify_headers(&arp);
+ if (r < 0)
+ return 0;
+
+ ipv4ll_run_state_machine(ll, IPV4LL_TRIGGER_PACKET, &arp);
+
+ return 0;
+}
+
+int sd_ipv4ll_set_index(sd_ipv4ll *ll, int interface_index) {
+ assert_return(ll, -EINVAL);
+ assert_return(interface_index >= -1, -EINVAL);
+ assert_return(ll->state == IPV4LL_STATE_INIT, -EBUSY);
+
+ ll->index = interface_index;
+
+ return 0;
+}
+
+int sd_ipv4ll_set_mac(sd_ipv4ll *ll, const struct ether_addr *addr) {
+ assert_return(ll, -EINVAL);
+ assert_return(ll->state == IPV4LL_STATE_INIT, -EBUSY);
+
+ memcpy(&ll->mac_addr.ether_addr_octet, addr, ETH_ALEN);
+
+ return 0;
+}
+
+int sd_ipv4ll_detach_event(sd_ipv4ll *ll) {
+ assert_return(ll, -EINVAL);
+
+ ll->event = sd_event_unref(ll->event);
+
+ return 0;
+}
+
+int sd_ipv4ll_attach_event(sd_ipv4ll *ll, sd_event *event, int 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) {
+ ipv4ll_stop(ll, IPV4LL_EVENT_STOP);
+ return r;
+ }
+ }
+
+ ll->event_priority = priority;
+
+ return 0;
+}
+
+int sd_ipv4ll_set_callback(sd_ipv4ll *ll, sd_ipv4ll_cb_t cb, void *userdata) {
+ assert_return(ll, -EINVAL);
+
+ ll->cb = cb;
+ ll->userdata = userdata;
+
+ return 0;
+}
+
+int sd_ipv4ll_get_address(sd_ipv4ll *ll, struct in_addr *address){
+ assert_return(ll, -EINVAL);
+ assert_return(address, -EINVAL);
+
+ if (ll->claimed_address == 0) {
+ return -ENOENT;
+ }
+
+ address->s_addr = ll->claimed_address;
+ return 0;
+}
+
+int sd_ipv4ll_start (sd_ipv4ll *ll) {
+ int r;
+
+ assert_return(ll, -EINVAL);
+ assert_return(ll->event, -EINVAL);
+ 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->address == 0)
+ ll->address = ipv4ll_pick_address(ll);
+
+ 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_monotonic(ll->event, &ll->timer, 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);
+}
+
+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;
+}
~ianmdlvl / elogind.git / blobdiff