Adding upstream version 255.4.upstream/255.4

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 617 insertions, 0 deletions

diff --git a/src/libsystemd-network/sd-ipv4acd.c b/src/libsystemd-network/sd-ipv4acd.c
new file mode 100644
index 0000000..0cc37a6
--- /dev/null
+++ b/src/libsystemd-network/sd-ipv4acd.c
@@ -0,0 +1,617 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/***
+  Copyright © 2014 Axis Communications AB. All rights reserved.
+***/
+
+#include <arpa/inet.h>
+#include <errno.h>
+#include <netinet/if_ether.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "sd-ipv4acd.h"
+
+#include "alloc-util.h"
+#include "arp-util.h"
+#include "ether-addr-util.h"
+#include "event-util.h"
+#include "fd-util.h"
+#include "in-addr-util.h"
+#include "memory-util.h"
+#include "network-common.h"
+#include "random-util.h"
+#include "siphash24.h"
+#include "string-table.h"
+#include "string-util.h"
+#include "time-util.h"
+
+/* Constants from the RFC */
+#define PROBE_WAIT_USEC (1U * USEC_PER_SEC)
+#define PROBE_NUM 3U
+#define PROBE_MIN_USEC (1U * USEC_PER_SEC)
+#define PROBE_MAX_USEC (2U * USEC_PER_SEC)
+#define ANNOUNCE_WAIT_USEC (2U * USEC_PER_SEC)
+#define ANNOUNCE_NUM 2U
+#define ANNOUNCE_INTERVAL_USEC (2U * USEC_PER_SEC)
+#define MAX_CONFLICTS 10U
+#define RATE_LIMIT_INTERVAL_USEC (60U * USEC_PER_SEC)
+#define DEFEND_INTERVAL_USEC (10U * USEC_PER_SEC)
+
+typedef enum IPv4ACDState {
+        IPV4ACD_STATE_INIT,
+        IPV4ACD_STATE_STARTED,
+        IPV4ACD_STATE_WAITING_PROBE,
+        IPV4ACD_STATE_PROBING,
+        IPV4ACD_STATE_WAITING_ANNOUNCE,
+        IPV4ACD_STATE_ANNOUNCING,
+        IPV4ACD_STATE_RUNNING,
+        _IPV4ACD_STATE_MAX,
+        _IPV4ACD_STATE_INVALID = -EINVAL,
+} IPv4ACDState;
+
+struct sd_ipv4acd {
+        unsigned n_ref;
+
+        IPv4ACDState state;
+        int ifindex;
+        int fd;
+
+        char *ifname;
+        unsigned n_iteration;
+        unsigned n_conflict;
+
+        sd_event_source *receive_message_event_source;
+        sd_event_source *timer_event_source;
+
+        usec_t defend_window;
+        struct in_addr address;
+
+        /* External */
+        struct ether_addr mac_addr;
+
+        sd_event *event;
+        int event_priority;
+        sd_ipv4acd_callback_t callback;
+        void *userdata;
+        sd_ipv4acd_check_mac_callback_t check_mac_callback;
+        void *check_mac_userdata;
+};
+
+#define log_ipv4acd_errno(acd, error, fmt, ...)         \
+        log_interface_prefix_full_errno(                \
+                "IPv4ACD: ",                            \
+                sd_ipv4acd, acd,                        \
+                error, fmt, ##__VA_ARGS__)
+#define log_ipv4acd(acd, fmt, ...)                      \
+        log_interface_prefix_full_errno_zerook(         \
+                "IPv4ACD: ",                            \
+                sd_ipv4acd, acd,                        \
+                0, fmt, ##__VA_ARGS__)
+
+static const char * const ipv4acd_state_table[_IPV4ACD_STATE_MAX] = {
+        [IPV4ACD_STATE_INIT]             = "init",
+        [IPV4ACD_STATE_STARTED]          = "started",
+        [IPV4ACD_STATE_WAITING_PROBE]    = "waiting-probe",
+        [IPV4ACD_STATE_PROBING]          = "probing",
+        [IPV4ACD_STATE_WAITING_ANNOUNCE] = "waiting-announce",
+        [IPV4ACD_STATE_ANNOUNCING]       = "announcing",
+        [IPV4ACD_STATE_RUNNING]          = "running",
+};
+
+DEFINE_PRIVATE_STRING_TABLE_LOOKUP_TO_STRING(ipv4acd_state, IPv4ACDState);
+
+static void ipv4acd_set_state(sd_ipv4acd *acd, IPv4ACDState st, bool reset_counter) {
+        assert(acd);
+        assert(st < _IPV4ACD_STATE_MAX);
+
+        if (st != acd->state)
+                log_ipv4acd(acd, "%s -> %s", ipv4acd_state_to_string(acd->state), ipv4acd_state_to_string(st));
+
+        if (st == acd->state && !reset_counter)
+                acd->n_iteration++;
+        else {
+                acd->state = st;
+                acd->n_iteration = 0;
+        }
+}
+
+static void ipv4acd_reset(sd_ipv4acd *acd) {
+        assert(acd);
+
+        (void) event_source_disable(acd->timer_event_source);
+        acd->receive_message_event_source = sd_event_source_disable_unref(acd->receive_message_event_source);
+
+        acd->fd = safe_close(acd->fd);
+
+        ipv4acd_set_state(acd, IPV4ACD_STATE_INIT, true);
+}
+
+static sd_ipv4acd *ipv4acd_free(sd_ipv4acd *acd) {
+        assert(acd);
+
+        ipv4acd_reset(acd);
+        sd_event_source_unref(acd->timer_event_source);
+        sd_ipv4acd_detach_event(acd);
+        free(acd->ifname);
+        return mfree(acd);
+}
+
+DEFINE_TRIVIAL_REF_UNREF_FUNC(sd_ipv4acd, sd_ipv4acd, ipv4acd_free);
+
+int sd_ipv4acd_new(sd_ipv4acd **ret) {
+        _cleanup_(sd_ipv4acd_unrefp) sd_ipv4acd *acd = NULL;
+
+        assert_return(ret, -EINVAL);
+
+        acd = new(sd_ipv4acd, 1);
+        if (!acd)
+                return -ENOMEM;
+
+        *acd = (sd_ipv4acd) {
+                .n_ref = 1,
+                .state = IPV4ACD_STATE_INIT,
+                .ifindex = -1,
+                .fd = -EBADF,
+        };
+
+        *ret = TAKE_PTR(acd);
+
+        return 0;
+}
+
+static void ipv4acd_client_notify(sd_ipv4acd *acd, int event) {
+        assert(acd);
+
+        if (!acd->callback)
+                return;
+
+        acd->callback(acd, event, acd->userdata);
+}
+
+int sd_ipv4acd_stop(sd_ipv4acd *acd) {
+        IPv4ACDState old_state;
+
+        if (!acd)
+                return 0;
+
+        old_state = acd->state;
+
+        ipv4acd_reset(acd);
+
+        if (old_state == IPV4ACD_STATE_INIT)
+                return 0;
+
+        log_ipv4acd(acd, "STOPPED");
+
+        ipv4acd_client_notify(acd, 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 *acd, usec_t usec, usec_t random_usec) {
+        usec_t next_timeout, time_now;
+
+        assert(acd);
+
+        next_timeout = usec;
+
+        if (random_usec > 0)
+                next_timeout += (usec_t) random_u64() % random_usec;
+
+        assert_se(sd_event_now(acd->event, CLOCK_BOOTTIME, &time_now) >= 0);
+
+        return event_reset_time(acd->event, &acd->timer_event_source,
+                                CLOCK_BOOTTIME,
+                                time_now + next_timeout, 0,
+                                ipv4acd_on_timeout, acd,
+                                acd->event_priority, "ipv4acd-timer", true);
+}
+
+static int ipv4acd_on_timeout(sd_event_source *s, uint64_t usec, void *userdata) {
+        sd_ipv4acd *acd = ASSERT_PTR(userdata);
+        int r = 0;
+
+        switch (acd->state) {
+
+        case IPV4ACD_STATE_STARTED:
+                acd->defend_window = 0;
+
+                ipv4acd_set_state(acd, IPV4ACD_STATE_WAITING_PROBE, true);
+
+                if (acd->n_conflict >= MAX_CONFLICTS) {
+                        log_ipv4acd(acd, "Max conflicts reached, delaying by %s",
+                                    FORMAT_TIMESPAN(RATE_LIMIT_INTERVAL_USEC, 0));
+                        r = ipv4acd_set_next_wakeup(acd, RATE_LIMIT_INTERVAL_USEC, PROBE_WAIT_USEC);
+                } else
+                        r = ipv4acd_set_next_wakeup(acd, 0, PROBE_WAIT_USEC);
+                if (r < 0)
+                        goto fail;
+
+                break;
+
+        case IPV4ACD_STATE_WAITING_PROBE:
+        case IPV4ACD_STATE_PROBING:
+                /* Send a probe */
+                r = arp_send_probe(acd->fd, acd->ifindex, &acd->address, &acd->mac_addr);
+                if (r < 0) {
+                        log_ipv4acd_errno(acd, r, "Failed to send ARP probe: %m");
+                        goto fail;
+                }
+
+                log_ipv4acd(acd, "Probing "IPV4_ADDRESS_FMT_STR, IPV4_ADDRESS_FMT_VAL(acd->address));
+
+                if (acd->n_iteration < PROBE_NUM - 2) {
+                        ipv4acd_set_state(acd, IPV4ACD_STATE_PROBING, false);
+
+                        r = ipv4acd_set_next_wakeup(acd, PROBE_MIN_USEC, (PROBE_MAX_USEC-PROBE_MIN_USEC));
+                        if (r < 0)
+                                goto fail;
+                } else {
+                        ipv4acd_set_state(acd, IPV4ACD_STATE_WAITING_ANNOUNCE, true);
+
+                        r = ipv4acd_set_next_wakeup(acd, ANNOUNCE_WAIT_USEC, 0);
+                        if (r < 0)
+                                goto fail;
+                }
+
+                break;
+
+        case IPV4ACD_STATE_ANNOUNCING:
+                if (acd->n_iteration >= ANNOUNCE_NUM - 1) {
+                        ipv4acd_set_state(acd, IPV4ACD_STATE_RUNNING, false);
+                        break;
+                }
+
+                _fallthrough_;
+        case IPV4ACD_STATE_WAITING_ANNOUNCE:
+                /* Send announcement packet */
+                r = arp_send_announcement(acd->fd, acd->ifindex, &acd->address, &acd->mac_addr);
+                if (r < 0) {
+                        log_ipv4acd_errno(acd, r, "Failed to send ARP announcement: %m");
+                        goto fail;
+                }
+
+                log_ipv4acd(acd, "Announcing "IPV4_ADDRESS_FMT_STR, IPV4_ADDRESS_FMT_VAL(acd->address));
+
+                ipv4acd_set_state(acd, IPV4ACD_STATE_ANNOUNCING, false);
+
+                r = ipv4acd_set_next_wakeup(acd, ANNOUNCE_INTERVAL_USEC, 0);
+                if (r < 0)
+                        goto fail;
+
+                if (acd->n_iteration == 0) {
+                        acd->n_conflict = 0;
+                        ipv4acd_client_notify(acd, SD_IPV4ACD_EVENT_BIND);
+                }
+
+                break;
+
+        default:
+                assert_not_reached();
+        }
+
+        return 0;
+
+fail:
+        sd_ipv4acd_stop(acd);
+        return 0;
+}
+
+static bool ipv4acd_arp_conflict(sd_ipv4acd *acd, const struct ether_arp *arp, bool announced) {
+        assert(acd);
+        assert(arp);
+
+        /* RFC 5227 section 2.1.1.
+         * "the host receives any ARP packet (Request *or* Reply) on the interface where the probe is
+         * being performed, where the packet's 'sender IP address' is the address being probed for,
+         * then the host MUST treat this address as being in use by some other host" */
+        if (memcmp(arp->arp_spa, &acd->address, sizeof(struct in_addr)) == 0)
+                return true;
+
+        if (announced)
+                /* the TPA matched instead of SPA, this is not a conflict */
+                return false;
+
+        /* "any ARP Probe where the packet's 'target IP address' is the address being probed for, and
+         * the packet's 'sender hardware address' is not the hardware address of any of the host's
+         * interfaces, then the host SHOULD similarly treat this as an address conflict" */
+        if (arp->ea_hdr.ar_op != htobe16(ARPOP_REQUEST))
+                return false; /* not ARP Request, ignoring. */
+        if (memeqzero(arp->arp_spa, sizeof(struct in_addr)) == 0)
+                return false; /* not ARP Probe, ignoring. */
+        if (memcmp(arp->arp_tpa, &acd->address, sizeof(struct in_addr)) != 0)
+                return false; /* target IP address does not match, BPF code is broken? */
+
+        if (acd->check_mac_callback &&
+            acd->check_mac_callback(acd, (const struct ether_addr*) arp->arp_sha, acd->check_mac_userdata) > 0)
+                /* sender hardware is one of the host's interfaces, ignoring. */
+                return false;
+
+        return true; /* conflict! */
+}
+
+static void ipv4acd_on_conflict(sd_ipv4acd *acd) {
+        assert(acd);
+
+        acd->n_conflict++;
+
+        log_ipv4acd(acd, "Conflict on "IPV4_ADDRESS_FMT_STR" (%u)", IPV4_ADDRESS_FMT_VAL(acd->address), acd->n_conflict);
+
+        ipv4acd_reset(acd);
+        ipv4acd_client_notify(acd, SD_IPV4ACD_EVENT_CONFLICT);
+}
+
+static int ipv4acd_on_packet(
+                sd_event_source *s,
+                int fd,
+                uint32_t revents,
+                void *userdata) {
+
+        sd_ipv4acd *acd = ASSERT_PTR(userdata);
+        struct ether_arp packet;
+        ssize_t n;
+        int r;
+
+        assert(s);
+        assert(fd >= 0);
+
+        n = recv(fd, &packet, sizeof(struct ether_arp), 0);
+        if (n < 0) {
+                if (ERRNO_IS_TRANSIENT(errno) || ERRNO_IS_DISCONNECT(errno))
+                        return 0;
+
+                log_ipv4acd_errno(acd, errno, "Failed to read ARP packet: %m");
+                goto fail;
+        }
+        if ((size_t) n != sizeof(struct ether_arp)) {
+                log_ipv4acd(acd, "Ignoring too short ARP packet.");
+                return 0;
+        }
+
+        switch (acd->state) {
+
+        case IPV4ACD_STATE_ANNOUNCING:
+        case IPV4ACD_STATE_RUNNING:
+
+                if (ipv4acd_arp_conflict(acd, &packet, true)) {
+                        usec_t ts;
+
+                        assert_se(sd_event_now(acd->event, CLOCK_BOOTTIME, &ts) >= 0);
+
+                        /* Defend address */
+                        if (ts > acd->defend_window) {
+                                acd->defend_window = ts + DEFEND_INTERVAL_USEC;
+                                r = arp_send_announcement(acd->fd, acd->ifindex, &acd->address, &acd->mac_addr);
+                                if (r < 0) {
+                                        log_ipv4acd_errno(acd, r, "Failed to send ARP announcement: %m");
+                                        goto fail;
+                                }
+
+                                log_ipv4acd(acd, "Defending "IPV4_ADDRESS_FMT_STR, IPV4_ADDRESS_FMT_VAL(acd->address));
+
+                        } else
+                                ipv4acd_on_conflict(acd);
+                }
+                break;
+
+        case IPV4ACD_STATE_WAITING_PROBE:
+        case IPV4ACD_STATE_PROBING:
+        case IPV4ACD_STATE_WAITING_ANNOUNCE:
+                if (ipv4acd_arp_conflict(acd, &packet, false))
+                        ipv4acd_on_conflict(acd);
+                break;
+
+        default:
+                assert_not_reached();
+        }
+
+        return 0;
+
+fail:
+        sd_ipv4acd_stop(acd);
+        return 0;
+}
+
+int sd_ipv4acd_set_ifindex(sd_ipv4acd *acd, int ifindex) {
+        assert_return(acd, -EINVAL);
+        assert_return(ifindex > 0, -EINVAL);
+        assert_return(acd->state == IPV4ACD_STATE_INIT, -EBUSY);
+
+        acd->ifindex = ifindex;
+
+        return 0;
+}
+
+int sd_ipv4acd_get_ifindex(sd_ipv4acd *acd) {
+        if (!acd)
+                return -EINVAL;
+
+        return acd->ifindex;
+}
+
+int sd_ipv4acd_set_ifname(sd_ipv4acd *acd, const char *ifname) {
+        assert_return(acd, -EINVAL);
+        assert_return(ifname, -EINVAL);
+
+        if (!ifname_valid_full(ifname, IFNAME_VALID_ALTERNATIVE))
+                return -EINVAL;
+
+        return free_and_strdup(&acd->ifname, ifname);
+}
+
+int sd_ipv4acd_get_ifname(sd_ipv4acd *acd, const char **ret) {
+        int r;
+
+        assert_return(acd, -EINVAL);
+
+        r = get_ifname(acd->ifindex, &acd->ifname);
+        if (r < 0)
+                return r;
+
+        if (ret)
+                *ret = acd->ifname;
+
+        return 0;
+}
+
+int sd_ipv4acd_set_mac(sd_ipv4acd *acd, const struct ether_addr *addr) {
+        int r;
+
+        assert_return(acd, -EINVAL);
+        assert_return(addr, -EINVAL);
+        assert_return(!ether_addr_is_null(addr), -EINVAL);
+
+        acd->mac_addr = *addr;
+
+        if (!sd_ipv4acd_is_running(acd))
+                return 0;
+
+        assert(acd->fd >= 0);
+        r = arp_update_filter(acd->fd, &acd->address, &acd->mac_addr);
+        if (r < 0) {
+                ipv4acd_reset(acd);
+                return r;
+        }
+
+        return 0;
+}
+
+int sd_ipv4acd_detach_event(sd_ipv4acd *acd) {
+        assert_return(acd, -EINVAL);
+
+        acd->event = sd_event_unref(acd->event);
+
+        return 0;
+}
+
+int sd_ipv4acd_attach_event(sd_ipv4acd *acd, sd_event *event, int64_t priority) {
+        int r;
+
+        assert_return(acd, -EINVAL);
+        assert_return(!acd->event, -EBUSY);
+
+        if (event)
+                acd->event = sd_event_ref(event);
+        else {
+                r = sd_event_default(&acd->event);
+                if (r < 0)
+                        return r;
+        }
+
+        acd->event_priority = priority;
+
+        return 0;
+}
+
+int sd_ipv4acd_set_callback(sd_ipv4acd *acd, sd_ipv4acd_callback_t cb, void *userdata) {
+        assert_return(acd, -EINVAL);
+
+        acd->callback = cb;
+        acd->userdata = userdata;
+
+        return 0;
+}
+
+int sd_ipv4acd_set_check_mac_callback(sd_ipv4acd *acd, sd_ipv4acd_check_mac_callback_t cb, void *userdata) {
+        assert_return(acd, -EINVAL);
+
+        acd->check_mac_callback = cb;
+        acd->check_mac_userdata = userdata;
+        return 0;
+}
+
+int sd_ipv4acd_set_address(sd_ipv4acd *acd, const struct in_addr *address) {
+        int r;
+
+        assert_return(acd, -EINVAL);
+        assert_return(address, -EINVAL);
+        assert_return(in4_addr_is_set(address), -EINVAL);
+
+        if (in4_addr_equal(&acd->address, address))
+                return 0;
+
+        acd->address = *address;
+
+        if (!sd_ipv4acd_is_running(acd))
+                return 0;
+
+        assert(acd->fd >= 0);
+        r = arp_update_filter(acd->fd, &acd->address, &acd->mac_addr);
+        if (r < 0)
+                goto fail;
+
+        r = ipv4acd_set_next_wakeup(acd, 0, 0);
+        if (r < 0)
+                goto fail;
+
+        ipv4acd_set_state(acd, IPV4ACD_STATE_STARTED, true);
+        return 0;
+
+fail:
+        ipv4acd_reset(acd);
+        return r;
+}
+
+int sd_ipv4acd_get_address(sd_ipv4acd *acd, struct in_addr *address) {
+        assert_return(acd, -EINVAL);
+        assert_return(address, -EINVAL);
+
+        *address = acd->address;
+
+        return 0;
+}
+
+int sd_ipv4acd_is_running(sd_ipv4acd *acd) {
+        assert_return(acd, false);
+
+        return acd->state != IPV4ACD_STATE_INIT;
+}
+
+int sd_ipv4acd_is_bound(sd_ipv4acd *acd) {
+        assert_return(acd, false);
+
+        return IN_SET(acd->state, IPV4ACD_STATE_ANNOUNCING, IPV4ACD_STATE_RUNNING);
+}
+
+int sd_ipv4acd_start(sd_ipv4acd *acd, bool reset_conflicts) {
+        int r;
+
+        assert_return(acd, -EINVAL);
+        assert_return(acd->event, -EINVAL);
+        assert_return(acd->ifindex > 0, -EINVAL);
+        assert_return(in4_addr_is_set(&acd->address), -EINVAL);
+        assert_return(!ether_addr_is_null(&acd->mac_addr), -EINVAL);
+        assert_return(acd->state == IPV4ACD_STATE_INIT, -EBUSY);
+
+        r = arp_network_bind_raw_socket(acd->ifindex, &acd->address, &acd->mac_addr);
+        if (r < 0)
+                return r;
+
+        close_and_replace(acd->fd, r);
+
+        if (reset_conflicts)
+                acd->n_conflict = 0;
+
+        r = sd_event_add_io(acd->event, &acd->receive_message_event_source, acd->fd, EPOLLIN, ipv4acd_on_packet, acd);
+        if (r < 0)
+                goto fail;
+
+        r = sd_event_source_set_priority(acd->receive_message_event_source, acd->event_priority);
+        if (r < 0)
+                goto fail;
+
+        (void) sd_event_source_set_description(acd->receive_message_event_source, "ipv4acd-receive-message");
+
+        r = ipv4acd_set_next_wakeup(acd, 0, 0);
+        if (r < 0)
+                goto fail;
+
+        ipv4acd_set_state(acd, IPV4ACD_STATE_STARTED, true);
+        return 0;
+
+fail:
+        ipv4acd_reset(acd);
+        return r;
+}