diff options
Diffstat (limited to 'src/libsystemd-network/sd-ipv4acd.c')
| -rw-r--r-- | src/libsystemd-network/sd-ipv4acd.c | 527 |
1 files changed, 527 insertions, 0 deletions
diff --git a/src/libsystemd-network/sd-ipv4acd.c b/src/libsystemd-network/sd-ipv4acd.c new file mode 100644 index 0000000000..f7880a891c --- /dev/null +++ b/src/libsystemd-network/sd-ipv4acd.c @@ -0,0 +1,527 @@ +/*** + 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_cb_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, 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) + return r; + } + + ll->event_priority = priority; + + return 0; +} + +int sd_ipv4acd_set_callback(sd_ipv4acd *ll, sd_ipv4acd_cb_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; +} |