/*** 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 "siphash24.h" #include "list.h" #include "refcnt.h" #include "random-util.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_STOPPED, _IPV4LL_STATE_MAX, _IPV4LL_STATE_INVALID = -1 } IPv4LLState; struct sd_ipv4ll { RefCount n_ref; 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; struct random_data *random_data; char *random_data_state; /* 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 sd_ipv4ll *ipv4ll_client_notify(sd_ipv4ll *ll, int event) { assert(ll); if (ll->cb) { ll = sd_ipv4ll_ref(ll); ll->cb(ll, event, ll->userdata); ll = sd_ipv4ll_unref(ll); } return ll; } static sd_ipv4ll *ipv4ll_stop(sd_ipv4ll *ll, int event) { 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_ipv4ll(ll, "STOPPED"); ll = ipv4ll_client_notify(ll, event); if (ll) { ll->claimed_address = 0; ipv4ll_set_state (ll, IPV4LL_STATE_INIT, 1); } return ll; } static int ipv4ll_pick_address(sd_ipv4ll *ll, be32_t *address) { be32_t addr; int r; int32_t random; assert(ll); assert(address); assert(ll->random_data); do { r = random_r(ll->random_data, &random); if (r < 0) return r; addr = htonl((random & 0x0000FFFF) | IPV4LL_NETWORK); } while (addr == ll->address || (ntohl(addr) & IPV4LL_NETMASK) != IPV4LL_NETWORK || (ntohl(addr) & 0x0000FF00) == 0x0000 || (ntohl(addr) & 0x0000FF00) == 0xFF00); *address = addr; return 0; } 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); assert_se(sd_event_now(ll->event, clock_boottime_or_monotonic(), &time_now) >= 0); 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; ll = ipv4ll_client_notify(ll, IPV4LL_EVENT_BIND); if (!ll || ll->state == IPV4LL_STATE_STOPPED) goto out; 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_now(ll->event, clock_boottime_or_monotonic(), &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"); ll = ipv4ll_client_notify(ll, IPV4LL_EVENT_CONFLICT); if (!ll || ll->state == IPV4LL_STATE_STOPPED) goto out; ll->claimed_address = 0; /* Pick a new address */ r = ipv4ll_pick_address(ll, &ll->address); if (r < 0) goto out; 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_time(ll->event, &ll->timer, clock_boottime_or_monotonic(), 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; r = sd_event_source_set_description(ll->timer, "ipv4ll-timer"); if (r < 0) goto out; } out: if (r < 0 && ll) 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 > 0, -EINVAL); assert_return(IN_SET(ll->state, IPV4LL_STATE_INIT, IPV4LL_STATE_STOPPED), -EBUSY); ll->index = interface_index; return 0; } int sd_ipv4ll_set_mac(sd_ipv4ll *ll, const struct ether_addr *addr) { bool need_restart = false; assert_return(ll, -EINVAL); assert_return(addr, -EINVAL); if (memcmp(&ll->mac_addr, addr, ETH_ALEN) == 0) return 0; if (!IN_SET(ll->state, IPV4LL_STATE_INIT, IPV4LL_STATE_STOPPED)) { log_ipv4ll(ll, "Changing MAC address on running IPv4LL " "client, restarting"); ll = ipv4ll_stop(ll, IPV4LL_EVENT_STOP); need_restart = true; } if (!ll) return 0; memcpy(&ll->mac_addr, addr, ETH_ALEN); if (need_restart) sd_ipv4ll_start(ll); 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_set_address_seed (sd_ipv4ll *ll, uint8_t seed[8]) { unsigned int entropy; int r; assert_return(ll, -EINVAL); assert_return(seed, -EINVAL); entropy = *seed; free(ll->random_data); free(ll->random_data_state); ll->random_data = new0(struct random_data, 1); ll->random_data_state = new0(char, 128); if (!ll->random_data || !ll->random_data_state) { r = -ENOMEM; goto error; } r = initstate_r((unsigned int)entropy, ll->random_data_state, 128, ll->random_data); if (r < 0) goto error; error: if (r < 0){ free(ll->random_data); free(ll->random_data_state); ll->random_data = NULL; ll->random_data_state = NULL; } return r; } bool sd_ipv4ll_is_running(sd_ipv4ll *ll) { assert_return(ll, false); return !IN_SET(ll->state, IPV4LL_STATE_INIT, IPV4LL_STATE_STOPPED); } #define HASH_KEY SD_ID128_MAKE(df,04,22,98,3f,ad,14,52,f9,87,2e,d1,9c,70,e2,f2) 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(IN_SET(ll->state, IPV4LL_STATE_INIT, IPV4LL_STATE_STOPPED), -EBUSY); ll->state = IPV4LL_STATE_INIT; 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_source_set_description(ll->receive_message, "ipv4ll-receive-message"); if (r < 0) goto out; r = sd_event_add_time(ll->event, &ll->timer, clock_boottime_or_monotonic(), now(clock_boottime_or_monotonic()), 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; r = sd_event_source_set_description(ll->timer, "ipv4ll-timer"); out: if (r < 0) ipv4ll_stop(ll, IPV4LL_EVENT_STOP); return 0; } int sd_ipv4ll_stop(sd_ipv4ll *ll) { ipv4ll_stop(ll, IPV4LL_EVENT_STOP); if (ll) ipv4ll_set_state(ll, IPV4LL_STATE_STOPPED, 1); return 0; } sd_ipv4ll *sd_ipv4ll_ref(sd_ipv4ll *ll) { if (ll) assert_se(REFCNT_INC(ll->n_ref) >= 2); return ll; } sd_ipv4ll *sd_ipv4ll_unref(sd_ipv4ll *ll) { if (ll && REFCNT_DEC(ll->n_ref) == 0) { 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_ipv4ll_detach_event(ll); free(ll->random_data); free(ll->random_data_state); free(ll); return NULL; } return ll; } DEFINE_TRIVIAL_CLEANUP_FUNC(sd_ipv4ll*, sd_ipv4ll_unref); #define _cleanup_ipv4ll_free_ _cleanup_(sd_ipv4ll_unrefp) 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->n_ref = REFCNT_INIT; ll->state = IPV4LL_STATE_INIT; ll->index = -1; ll->fd = -1; *ret = ll; ll = NULL; return 0; }