Adding upstream version 247.3.upstream/247.3upstream

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

1 files changed, 1719 insertions, 0 deletions

diff --git a/src/network/networkd-dhcp6.c b/src/network/networkd-dhcp6.c
new file mode 100644
index 0000000..d4d4182
--- /dev/null
+++ b/src/network/networkd-dhcp6.c
@@ -0,0 +1,1719 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/***
+  Copyright © 2014 Intel Corporation. All rights reserved.
+***/
+
+#include <netinet/in.h>
+#include <linux/if.h>
+#include <linux/if_arp.h>
+
+#include "sd-dhcp6-client.h"
+
+#include "escape.h"
+#include "hashmap.h"
+#include "hostname-util.h"
+#include "missing_network.h"
+#include "network-internal.h"
+#include "networkd-address.h"
+#include "networkd-dhcp6.h"
+#include "networkd-link.h"
+#include "networkd-manager.h"
+#include "networkd-radv.h"
+#include "siphash24.h"
+#include "string-table.h"
+#include "string-util.h"
+#include "radv-internal.h"
+#include "web-util.h"
+
+bool link_dhcp6_pd_is_enabled(Link *link) {
+        assert(link);
+
+        if (!link->network)
+                return false;
+
+        return link->network->dhcp6_pd;
+}
+
+static bool dhcp6_lease_has_pd_prefix(sd_dhcp6_lease *lease) {
+        uint32_t lifetime_preferred, lifetime_valid;
+        union in_addr_union pd_prefix;
+        uint8_t pd_prefix_len;
+
+        if (!lease)
+                return false;
+
+        sd_dhcp6_lease_reset_pd_prefix_iter(lease);
+
+        return sd_dhcp6_lease_get_pd(lease, &pd_prefix.in6, &pd_prefix_len, &lifetime_preferred, &lifetime_valid) >= 0;
+}
+
+DHCP6DelegatedPrefix *dhcp6_pd_free(DHCP6DelegatedPrefix *p) {
+        if (!p)
+                return NULL;
+
+        if (p->link && p->link->manager) {
+                hashmap_remove(p->link->manager->dhcp6_prefixes, &p->prefix);
+                set_remove(p->link->manager->dhcp6_pd_prefixes, p);
+        }
+
+        link_unref(p->link);
+        return mfree(p);
+}
+
+static void dhcp6_pd_hash_func(const DHCP6DelegatedPrefix *p, struct siphash *state) {
+        assert(p);
+
+        siphash24_compress(&p->pd_prefix, sizeof(p->pd_prefix), state);
+        siphash24_compress(&p->link, sizeof(p->link), state);
+}
+
+static int dhcp6_pd_compare_func(const DHCP6DelegatedPrefix *a, const DHCP6DelegatedPrefix *b) {
+        int r;
+
+        r = memcmp(&a->pd_prefix, &b->pd_prefix, sizeof(a->pd_prefix));
+        if (r != 0)
+                return r;
+
+        return CMP(a->link, b->link);
+}
+
+DEFINE_HASH_OPS(dhcp6_pd_hash_ops, DHCP6DelegatedPrefix, dhcp6_pd_hash_func, dhcp6_pd_compare_func);
+
+static Link *dhcp6_pd_get_link_by_prefix(Link *link, const union in_addr_union *prefix) {
+        DHCP6DelegatedPrefix *pd;
+
+        assert(link);
+        assert(link->manager);
+        assert(prefix);
+
+        pd = hashmap_get(link->manager->dhcp6_prefixes, &prefix->in6);
+        if (!pd)
+                return NULL;
+
+        return pd->link;
+}
+
+static int dhcp6_pd_get_assigned_prefix(Link *link, const union in_addr_union *pd_prefix, union in_addr_union *ret_prefix) {
+        DHCP6DelegatedPrefix *pd, in;
+
+        assert(link);
+        assert(link->manager);
+        assert(pd_prefix);
+        assert(ret_prefix);
+
+        in = (DHCP6DelegatedPrefix) {
+                .pd_prefix = pd_prefix->in6,
+                .link = link,
+        };
+
+        pd = set_get(link->manager->dhcp6_pd_prefixes, &in);
+        if (!pd)
+                return -ENOENT;
+
+        ret_prefix->in6 = pd->prefix;
+        return 0;
+}
+
+static int dhcp6_pd_remove_old(Link *link, bool force);
+
+static int dhcp6_pd_address_callback(Address *address) {
+        Address *a;
+
+        assert(address);
+        assert(address->link);
+
+        /* Make this called only once */
+        SET_FOREACH(a, address->link->dhcp6_pd_addresses)
+                a->callback = NULL;
+
+        return dhcp6_pd_remove_old(address->link, true);
+}
+
+static int dhcp6_pd_remove_old(Link *link, bool force) {
+        Address *address;
+        Route *route;
+        int k, r = 0;
+
+        assert(link);
+        assert(link->manager);
+
+        if (!force && (link->dhcp6_pd_address_messages != 0 || link->dhcp6_pd_route_configured != 0))
+                return 0;
+
+        if (set_isempty(link->dhcp6_pd_addresses_old) && set_isempty(link->dhcp6_pd_routes_old))
+                return 0;
+
+        if (!force) {
+                bool set_callback = !set_isempty(link->dhcp6_pd_addresses);
+
+                SET_FOREACH(address, link->dhcp6_pd_addresses)
+                        if (address_is_ready(address)) {
+                                set_callback = false;
+                                break;
+                        }
+
+                if (set_callback) {
+                        SET_FOREACH(address, link->dhcp6_pd_addresses)
+                                address->callback = dhcp6_pd_address_callback;
+                        return 0;
+                }
+        }
+
+        log_link_debug(link, "Removing old DHCPv6 Prefix Delegation addresses and routes.");
+
+        link_dirty(link);
+
+        SET_FOREACH(route, link->dhcp6_pd_routes_old) {
+                k = route_remove(route, NULL, link, NULL);
+                if (k < 0)
+                        r = k;
+
+                if (link->radv)
+                        (void) sd_radv_remove_prefix(link->radv, &route->dst.in6, 64);
+                dhcp6_pd_free(hashmap_get(link->manager->dhcp6_prefixes, &route->dst.in6));
+        }
+
+        SET_FOREACH(address, link->dhcp6_pd_addresses_old) {
+                k = address_remove(address, link, NULL);
+                if (k < 0)
+                        r = k;
+        }
+
+        return r;
+}
+
+int dhcp6_pd_remove(Link *link) {
+        Address *address;
+        Route *route;
+        int k, r = 0;
+
+        assert(link);
+        assert(link->manager);
+
+        if (!link_dhcp6_pd_is_enabled(link))
+                return 0;
+
+        link->dhcp6_pd_address_configured = false;
+        link->dhcp6_pd_route_configured = false;
+
+        k = dhcp6_pd_remove_old(link, true);
+        if (k < 0)
+                r = k;
+
+        if (set_isempty(link->dhcp6_pd_addresses) && set_isempty(link->dhcp6_pd_routes))
+                return r;
+
+        log_link_debug(link, "Removing DHCPv6 Prefix Delegation addresses and routes.");
+
+        link_dirty(link);
+
+        SET_FOREACH(route, link->dhcp6_pd_routes) {
+                k = route_remove(route, NULL, link, NULL);
+                if (k < 0)
+                        r = k;
+
+                if (link->radv)
+                        (void) sd_radv_remove_prefix(link->radv, &route->dst.in6, 64);
+                dhcp6_pd_free(hashmap_get(link->manager->dhcp6_prefixes, &route->dst.in6));
+        }
+
+        SET_FOREACH(address, link->dhcp6_pd_addresses) {
+                k = address_remove(address, link, NULL);
+                if (k < 0)
+                        r = k;
+        }
+
+        return r;
+}
+
+static int dhcp6_pd_route_handler(sd_netlink *nl, sd_netlink_message *m, Link *link) {
+        int r;
+
+        assert(link);
+        assert(link->dhcp6_pd_route_messages > 0);
+
+        link->dhcp6_pd_route_messages--;
+
+        if (IN_SET(link->state, LINK_STATE_FAILED, LINK_STATE_LINGER))
+                return 1;
+
+        r = sd_netlink_message_get_errno(m);
+        if (r < 0 && r != -EEXIST) {
+                log_link_message_warning_errno(link, m, r, "Failed to add DHCPv6 Prefix Delegation route");
+                link_enter_failed(link);
+                return 1;
+        }
+
+        if (link->dhcp6_pd_route_messages == 0) {
+                log_link_debug(link, "DHCPv6 prefix delegation routes set");
+                if (link->dhcp6_pd_prefixes_assigned)
+                        link->dhcp6_pd_route_configured = true;
+
+                r = dhcp6_pd_remove_old(link, false);
+                if (r < 0) {
+                        link_enter_failed(link);
+                        return 1;
+                }
+
+                link_check_ready(link);
+        }
+
+        return 1;
+}
+
+static int dhcp6_set_pd_route(Link *link, const union in_addr_union *prefix, const union in_addr_union *pd_prefix) {
+        _cleanup_(dhcp6_pd_freep) DHCP6DelegatedPrefix *pd = NULL;
+        _cleanup_(route_freep) Route *route = NULL;
+        Link *assigned_link;
+        Route *ret;
+        int r;
+
+        assert(link);
+        assert(link->manager);
+        assert(prefix);
+        assert(pd_prefix);
+
+        r = route_new(&route);
+        if (r < 0)
+                return r;
+
+        route->family = AF_INET6;
+        route->dst = *prefix;
+        route->dst_prefixlen = 64;
+
+        r = route_configure(route, link, dhcp6_pd_route_handler, &ret);
+        if (r < 0)
+                return log_link_error_errno(link, r, "Failed to set DHCPv6 prefix route: %m");
+
+        link->dhcp6_pd_route_messages++;
+
+        r = set_ensure_put(&link->dhcp6_pd_routes, &route_hash_ops, ret);
+        if (r < 0)
+                return log_link_error_errno(link, r, "Failed to store DHCPv6 prefix route: %m");
+
+        (void) set_remove(link->dhcp6_pd_routes_old, ret);
+
+        assigned_link = dhcp6_pd_get_link_by_prefix(link, prefix);
+        if (assigned_link) {
+                assert(assigned_link == link);
+                return 0;
+        }
+
+        pd = new(DHCP6DelegatedPrefix, 1);
+        if (!pd)
+                return log_oom();
+
+        *pd = (DHCP6DelegatedPrefix) {
+                .prefix = prefix->in6,
+                .pd_prefix = pd_prefix->in6,
+                .link = link_ref(link),
+        };
+
+        r = hashmap_ensure_allocated(&link->manager->dhcp6_prefixes, &in6_addr_hash_ops);
+        if (r < 0)
+                return log_oom();
+
+        r = hashmap_put(link->manager->dhcp6_prefixes, &pd->prefix, pd);
+        if (r < 0)
+                return log_link_error_errno(link, r, "Failed to store DHCPv6 prefix route at manager: %m");
+
+        r = set_ensure_put(&link->manager->dhcp6_pd_prefixes, &dhcp6_pd_hash_ops, pd);
+        if (r < 0)
+                return log_link_error_errno(link, r, "Failed to store DHCPv6 prefix route at manager: %m");
+
+        TAKE_PTR(pd);
+        return 0;
+}
+
+static int dhcp6_pd_address_handler(sd_netlink *rtnl, sd_netlink_message *m, Link *link) {
+        int r;
+
+        assert(link);
+        assert(link->dhcp6_pd_address_messages > 0);
+
+        link->dhcp6_pd_address_messages--;
+
+        if (IN_SET(link->state, LINK_STATE_FAILED, LINK_STATE_LINGER))
+                return 1;
+
+        r = sd_netlink_message_get_errno(m);
+        if (r < 0 && r != -EEXIST) {
+                log_link_message_warning_errno(link, m, r, "Could not set DHCPv6 delegated prefix address");
+                link_enter_failed(link);
+                return 1;
+        } else if (r >= 0)
+                (void) manager_rtnl_process_address(rtnl, m, link->manager);
+
+        if (link->dhcp6_pd_address_messages == 0) {
+                log_link_debug(link, "DHCPv6 delegated prefix addresses set");
+                if (link->dhcp6_pd_prefixes_assigned)
+                        link->dhcp6_pd_address_configured = true;
+
+                r = dhcp6_pd_remove_old(link, false);
+                if (r < 0) {
+                        link_enter_failed(link);
+                        return 1;
+                }
+
+                r = link_set_routes(link);
+                if (r < 0) {
+                        link_enter_failed(link);
+                        return 1;
+                }
+        }
+
+        return 1;
+}
+
+static int dhcp6_set_pd_address(Link *link,
+                                const union in_addr_union *prefix,
+                                uint8_t prefix_len,
+                                uint32_t lifetime_preferred,
+                                uint32_t lifetime_valid) {
+
+        _cleanup_(address_freep) Address *address = NULL;
+        Address *ret;
+        int r;
+
+        assert(link);
+        assert(link->network);
+        assert(prefix);
+
+        if (!link->network->dhcp6_pd_assign)
+                return 0;
+
+        r = address_new(&address);
+        if (r < 0)
+                return log_link_error_errno(link, r, "Failed to allocate address for DHCPv6 delegated prefix: %m");
+
+        address->in_addr = *prefix;
+
+        if (!in_addr_is_null(AF_INET6, &link->network->dhcp6_pd_token))
+                memcpy(address->in_addr.in6.s6_addr + 8, link->network->dhcp6_pd_token.in6.s6_addr + 8, 8);
+        else {
+                r = generate_ipv6_eui_64_address(link, &address->in_addr.in6);
+                if (r < 0)
+                        return log_link_warning_errno(link, r, "Failed to generate EUI64 address for acquired DHCPv6 delegated prefix: %m");
+        }
+
+        address->prefixlen = prefix_len;
+        address->family = AF_INET6;
+        address->cinfo.ifa_prefered = lifetime_preferred;
+        address->cinfo.ifa_valid = lifetime_valid;
+
+        r = address_configure(address, link, dhcp6_pd_address_handler, true, &ret);
+        if (r < 0)
+                return log_link_error_errno(link, r, "Failed to set DHCPv6 delegated prefix address: %m");
+
+        link->dhcp6_pd_address_messages++;
+
+        r = set_ensure_put(&link->dhcp6_pd_addresses, &address_hash_ops, ret);
+        if (r < 0)
+                return log_link_error_errno(link, r, "Failed to store DHCPv6 delegated prefix address: %m");
+
+        (void) set_remove(link->dhcp6_pd_addresses_old, ret);
+
+        return 0;
+}
+
+static int dhcp6_pd_assign_prefix(Link *link, const union in_addr_union *prefix, const union in_addr_union *pd_prefix,
+                                  uint8_t prefix_len, uint32_t lifetime_preferred, uint32_t lifetime_valid) {
+        int r;
+
+        assert(link);
+        assert(link->network);
+        assert(prefix);
+
+        if (link->network->dhcp6_pd_announce) {
+                r = radv_add_prefix(link, &prefix->in6, prefix_len, lifetime_preferred, lifetime_valid);
+                if (r < 0)
+                        return r;
+        }
+
+        r = dhcp6_set_pd_route(link, prefix, pd_prefix);
+        if (r < 0)
+                return r;
+
+        r = dhcp6_set_pd_address(link, prefix, prefix_len, lifetime_preferred, lifetime_valid);
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+static bool link_has_preferred_subnet_id(Link *link) {
+        if (!link->network)
+                return false;
+
+        return link->network->dhcp6_pd_subnet_id >= 0;
+}
+
+static int dhcp6_get_preferred_delegated_prefix(
+                Link *link,
+                const union in_addr_union *masked_pd_prefix,
+                uint8_t pd_prefix_len,
+                union in_addr_union *ret) {
+
+        /* We start off with the original PD prefix we have been assigned and iterate from there */
+        union in_addr_union prefix;
+        uint64_t n_prefixes;
+        Link *assigned_link;
+        int r;
+
+        assert(link);
+        assert(link->manager);
+        assert(masked_pd_prefix);
+        assert(pd_prefix_len <= 64);
+
+        n_prefixes = UINT64_C(1) << (64 - pd_prefix_len);
+        prefix = *masked_pd_prefix;
+
+        if (link_has_preferred_subnet_id(link)) {
+                uint64_t subnet_id = link->network->dhcp6_pd_subnet_id;
+
+                /* If the link has a preference for a particular subnet id try to allocate that */
+                if (subnet_id >= n_prefixes)
+                        return log_link_warning_errno(link, SYNTHETIC_ERRNO(ERANGE),
+                                                      "subnet id %" PRIu64 " is out of range. Only have %" PRIu64 " subnets.",
+                                                      subnet_id, n_prefixes);
+
+                r = in_addr_prefix_nth(AF_INET6, &prefix, 64, subnet_id);
+                if (r < 0)
+                        return log_link_warning_errno(link, r,
+                                                      "subnet id %" PRIu64 " is out of range. Only have %" PRIu64 " subnets.",
+                                                      subnet_id, n_prefixes);
+
+                /* Verify that the prefix we did calculate fits in the pd prefix.
+                 * This should not fail as we checked the prefix size beforehand */
+                assert_se(in_addr_prefix_covers(AF_INET6, masked_pd_prefix, pd_prefix_len, &prefix) > 0);
+
+                assigned_link = dhcp6_pd_get_link_by_prefix(link, &prefix);
+                if (assigned_link && assigned_link != link) {
+                        _cleanup_free_ char *assigned_buf = NULL;
+
+                        (void) in_addr_to_string(AF_INET6, &prefix, &assigned_buf);
+                        return log_link_warning_errno(link, SYNTHETIC_ERRNO(EAGAIN),
+                                                      "The requested prefix %s is already assigned to another link.",
+                                                      strna(assigned_buf));
+                }
+
+                *ret = prefix;
+                return 0;
+        }
+
+        for (uint64_t n = 0; n < n_prefixes; n++) {
+                /* If we do not have an allocation preference just iterate
+                 * through the address space and return the first free prefix. */
+                assigned_link = dhcp6_pd_get_link_by_prefix(link, &prefix);
+                if (!assigned_link || assigned_link == link) {
+                        *ret = prefix;
+                        return 0;
+                }
+
+                r = in_addr_prefix_next(AF_INET6, &prefix, 64);
+                if (r < 0)
+                        return log_link_warning_errno(link, r, "Can't allocate another prefix. Out of address space?: %m");
+        }
+
+        return log_link_warning_errno(link, SYNTHETIC_ERRNO(ERANGE), "Couldn't find a suitable prefix. Ran out of address space.");
+}
+
+static void dhcp6_pd_prefix_distribute(Link *dhcp6_link,
+                                      const union in_addr_union *masked_pd_prefix,
+                                      uint8_t pd_prefix_len,
+                                      uint32_t lifetime_preferred,
+                                      uint32_t lifetime_valid,
+                                      bool assign_preferred_subnet_id) {
+
+        Link *link;
+        int r;
+
+        assert(dhcp6_link);
+        assert(dhcp6_link->manager);
+        assert(masked_pd_prefix);
+        assert(pd_prefix_len <= 64);
+
+        HASHMAP_FOREACH(link, dhcp6_link->manager->links) {
+                _cleanup_free_ char *assigned_buf = NULL;
+                union in_addr_union assigned_prefix;
+
+                if (link == dhcp6_link)
+                        continue;
+
+                if (!link_dhcp6_pd_is_enabled(link))
+                        continue;
+
+                if (IN_SET(link->state, LINK_STATE_FAILED, LINK_STATE_LINGER))
+                        continue;
+
+                if (assign_preferred_subnet_id != link_has_preferred_subnet_id(link))
+                        continue;
+
+                r = dhcp6_pd_get_assigned_prefix(link, masked_pd_prefix, &assigned_prefix);
+                if (r < 0) {
+                        r = dhcp6_get_preferred_delegated_prefix(link, masked_pd_prefix, pd_prefix_len, &assigned_prefix);
+                        if (r < 0) {
+                                link->dhcp6_pd_prefixes_assigned = false;
+                                continue;
+                        }
+                }
+
+                (void) in_addr_to_string(AF_INET6, &assigned_prefix, &assigned_buf);
+                r = dhcp6_pd_assign_prefix(link, &assigned_prefix, masked_pd_prefix, 64,
+                                           lifetime_preferred, lifetime_valid);
+                if (r < 0) {
+                        log_link_error_errno(link, r, "Unable to assign/update prefix %s/64: %m",
+                                             strna(assigned_buf));
+                        link_enter_failed(link);
+                } else
+                        log_link_debug(link, "Assigned prefix %s/64", strna(assigned_buf));
+        }
+}
+
+static int dhcp6_pd_prepare(Link *link) {
+        Address *address;
+        Route *route;
+        int r;
+
+        if (IN_SET(link->state, LINK_STATE_FAILED, LINK_STATE_LINGER))
+                return 0;
+
+        if (!link_dhcp6_pd_is_enabled(link))
+                return 0;
+
+        link_dirty(link);
+
+        link->dhcp6_pd_address_configured = false;
+        link->dhcp6_pd_route_configured = false;
+        link->dhcp6_pd_prefixes_assigned = true;
+
+        while ((address = set_steal_first(link->dhcp6_pd_addresses))) {
+                r = set_ensure_put(&link->dhcp6_pd_addresses_old, &address_hash_ops, address);
+                if (r < 0)
+                        return log_link_error_errno(link, r, "Failed to store old DHCPv6 Prefix Delegation address: %m");
+        }
+
+        while ((route = set_steal_first(link->dhcp6_pd_routes))) {
+                r = set_ensure_put(&link->dhcp6_pd_routes_old, &route_hash_ops, route);
+                if (r < 0)
+                        return log_link_error_errno(link, r, "Failed to store old DHCPv6 Prefix Delegation route: %m");
+        }
+
+        return 0;
+}
+
+static int dhcp6_pd_finalize(Link *link) {
+        int r;
+
+        if (IN_SET(link->state, LINK_STATE_FAILED, LINK_STATE_LINGER))
+                return 0;
+
+        if (!link_dhcp6_pd_is_enabled(link))
+                return 0;
+
+        if (link->dhcp6_pd_address_messages == 0) {
+                if (link->dhcp6_pd_prefixes_assigned)
+                        link->dhcp6_pd_address_configured = true;
+        } else {
+                log_link_debug(link, "Setting DHCPv6 PD addresses");
+                /* address_handler calls link_set_routes() and link_set_nexthop(). Before they are
+                 * called, the related flags must be cleared. Otherwise, the link becomes configured
+                 * state before routes are configured. */
+                link->static_routes_configured = false;
+                link->static_nexthops_configured = false;
+        }
+
+        if (link->dhcp6_pd_route_messages == 0) {
+                if (link->dhcp6_pd_prefixes_assigned)
+                        link->dhcp6_pd_route_configured = true;
+        } else
+                log_link_debug(link, "Setting DHCPv6 PD routes");
+
+        r = dhcp6_pd_remove_old(link, false);
+        if (r < 0)
+                return r;
+
+        if (link->dhcp6_pd_address_configured && link->dhcp6_pd_route_configured)
+                link_check_ready(link);
+        else
+                link_set_state(link, LINK_STATE_CONFIGURING);
+
+        return 0;
+}
+
+static void dhcp6_pd_prefix_lost(Link *dhcp6_link) {
+        Link *link;
+        int r;
+
+        assert(dhcp6_link);
+        assert(dhcp6_link->manager);
+
+        HASHMAP_FOREACH(link, dhcp6_link->manager->links) {
+                if (link == dhcp6_link)
+                        continue;
+
+                r = dhcp6_pd_remove(link);
+                if (r < 0)
+                        link_enter_failed(link);
+        }
+}
+
+static int dhcp6_remove_old(Link *link, bool force);
+
+static int dhcp6_address_callback(Address *address) {
+        Address *a;
+
+        assert(address);
+        assert(address->link);
+
+        /* Make this called only once */
+        SET_FOREACH(a, address->link->dhcp6_addresses)
+                a->callback = NULL;
+
+        return dhcp6_remove_old(address->link, true);
+}
+
+static int dhcp6_remove_old(Link *link, bool force) {
+        Address *address;
+        Route *route;
+        int k, r = 0;
+
+        assert(link);
+
+        if (!force && (!link->dhcp6_address_configured || !link->dhcp6_route_configured))
+                return 0;
+
+        if (set_isempty(link->dhcp6_addresses_old) && set_isempty(link->dhcp6_routes_old))
+                return 0;
+
+        if (!force) {
+                bool set_callback = !set_isempty(link->dhcp6_addresses);
+
+                SET_FOREACH(address, link->dhcp6_addresses)
+                        if (address_is_ready(address)) {
+                                set_callback = false;
+                                break;
+                        }
+
+                if (set_callback) {
+                        SET_FOREACH(address, link->dhcp6_addresses)
+                                address->callback = dhcp6_address_callback;
+                        return 0;
+                }
+        }
+
+        log_link_debug(link, "Removing old DHCPv6 addresses and routes.");
+
+        link_dirty(link);
+
+        SET_FOREACH(route, link->dhcp6_routes_old) {
+                k = route_remove(route, NULL, link, NULL);
+                if (k < 0)
+                        r = k;
+        }
+
+        SET_FOREACH(address, link->dhcp6_addresses_old) {
+                k = address_remove(address, link, NULL);
+                if (k < 0)
+                        r = k;
+        }
+
+        return r;
+}
+
+static int dhcp6_remove(Link *link) {
+        Address *address;
+        Route *route;
+        int k, r = 0;
+
+        assert(link);
+
+        link->dhcp6_address_configured = false;
+        link->dhcp6_route_configured = false;
+
+        k = dhcp6_remove_old(link, true);
+        if (k < 0)
+                r = k;
+
+        if (set_isempty(link->dhcp6_addresses) && set_isempty(link->dhcp6_routes))
+                return r;
+
+        log_link_debug(link, "Removing DHCPv6 addresses and routes.");
+
+        link_dirty(link);
+
+        SET_FOREACH(route, link->dhcp6_routes) {
+                k = route_remove(route, NULL, link, NULL);
+                if (k < 0)
+                        r = k;
+        }
+
+        SET_FOREACH(address, link->dhcp6_addresses) {
+                k = address_remove(address, link, NULL);
+                if (k < 0)
+                        r = k;
+        }
+
+        return r;
+}
+
+static int dhcp6_route_handler(sd_netlink *nl, sd_netlink_message *m, Link *link) {
+        int r;
+
+        assert(link);
+        assert(link->dhcp6_route_messages > 0);
+
+        link->dhcp6_route_messages--;
+
+        if (IN_SET(link->state, LINK_STATE_FAILED, LINK_STATE_LINGER))
+                return 1;
+
+        r = sd_netlink_message_get_errno(m);
+        if (r < 0 && r != -EEXIST) {
+                log_link_message_warning_errno(link, m, r, "Failed to add unreachable route for DHCPv6 delegated subnet");
+                link_enter_failed(link);
+                return 1;
+        }
+
+        if (link->dhcp6_route_messages == 0) {
+                log_link_debug(link, "Unreachable routes for DHCPv6 delegated subnets set");
+                link->dhcp6_route_configured = true;
+
+                r = dhcp6_remove_old(link, false);
+                if (r < 0) {
+                        link_enter_failed(link);
+                        return 1;
+                }
+
+                link_check_ready(link);
+        }
+
+        return 1;
+}
+
+static int dhcp6_set_unreachable_route(Link *link, const union in_addr_union *addr, uint8_t prefixlen) {
+        _cleanup_(route_freep) Route *route = NULL;
+        _cleanup_free_ char *buf = NULL;
+        Route *ret;
+        int r;
+
+        assert(link);
+        assert(addr);
+
+        (void) in_addr_to_string(AF_INET6, addr, &buf);
+
+        if (prefixlen > 64) {
+                log_link_debug(link, "PD Prefix length > 64, ignoring prefix %s/%u",
+                               strna(buf), prefixlen);
+                return 0;
+        }
+
+        if (prefixlen == 64) {
+                log_link_debug(link, "Not adding a blocking route for DHCPv6 delegated subnet %s/64 since distributed prefix is 64",
+                               strna(buf));
+                return 1;
+        }
+
+        if (prefixlen < 48)
+                log_link_warning(link, "PD Prefix length < 48, looks unusual %s/%u",
+                                 strna(buf), prefixlen);
+
+        r = route_new(&route);
+        if (r < 0)
+                return log_oom();
+
+        route->family = AF_INET6;
+        route->dst = *addr;
+        route->dst_prefixlen = prefixlen;
+        route->table = link_get_dhcp_route_table(link);
+        route->type = RTN_UNREACHABLE;
+
+        r = route_configure(route, link, dhcp6_route_handler, &ret);
+        if (r < 0)
+                return log_link_error_errno(link, r, "Failed to set unreachable route for DHCPv6 delegated subnet %s/%u: %m",
+                                            strna(buf), prefixlen);
+
+        link->dhcp6_route_messages++;
+
+        r = set_ensure_put(&link->dhcp6_routes, &route_hash_ops, ret);
+        if (r < 0)
+                return log_link_error_errno(link, r, "Failed to store unreachable route for DHCPv6 delegated subnet %s/%u: %m",
+                                            strna(buf), prefixlen);
+
+        (void) set_remove(link->dhcp6_routes_old, ret);
+
+        return 1;
+}
+
+static int dhcp6_pd_prefix_acquired(Link *dhcp6_link) {
+        Link *link;
+        int r;
+
+        assert(dhcp6_link);
+        assert(dhcp6_link->dhcp6_lease);
+
+        HASHMAP_FOREACH(link, dhcp6_link->manager->links) {
+                if (link == dhcp6_link)
+                        continue;
+
+                r = dhcp6_pd_prepare(link);
+                if (r < 0)
+                        link_enter_failed(link);
+        }
+
+        for (sd_dhcp6_lease_reset_pd_prefix_iter(dhcp6_link->dhcp6_lease);;) {
+                uint32_t lifetime_preferred, lifetime_valid;
+                union in_addr_union pd_prefix, prefix;
+                uint8_t pd_prefix_len;
+
+                r = sd_dhcp6_lease_get_pd(dhcp6_link->dhcp6_lease, &pd_prefix.in6, &pd_prefix_len,
+                                          &lifetime_preferred, &lifetime_valid);
+                if (r < 0)
+                        break;
+
+                r = dhcp6_set_unreachable_route(dhcp6_link, &pd_prefix, pd_prefix_len);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        continue;
+
+                /* We are doing prefix allocation in two steps:
+                 * 1. all those links that have a preferred subnet id will be assigned their subnet
+                 * 2. all those links that remain will receive prefixes in sequential order. Prefixes
+                 *    that were previously already allocated to another link will be skipped.
+                 * The assignment has to be split in two phases since subnet id
+                 * preferences should be honored. Meaning that any subnet id should be
+                 * handed out to the requesting link and not to some link that didn't
+                 * specify any preference. */
+
+                assert(pd_prefix_len <= 64);
+
+                prefix = pd_prefix;
+                r = in_addr_mask(AF_INET6, &prefix, pd_prefix_len);
+                if (r < 0)
+                        return log_link_error_errno(dhcp6_link, r, "Failed to mask DHCPv6 PD prefix: %m");
+
+                if (DEBUG_LOGGING) {
+                        uint64_t n_prefixes = UINT64_C(1) << (64 - pd_prefix_len);
+                        _cleanup_free_ char *buf = NULL;
+
+                        (void) in_addr_to_string(AF_INET6, &prefix, &buf);
+                        log_link_debug(dhcp6_link, "Assigning up to %" PRIu64 " prefixes from %s/%u",
+                                       n_prefixes, strna(buf), pd_prefix_len);
+                }
+
+                dhcp6_pd_prefix_distribute(dhcp6_link,
+                                           &prefix,
+                                           pd_prefix_len,
+                                           lifetime_preferred,
+                                           lifetime_valid,
+                                           true);
+
+                dhcp6_pd_prefix_distribute(dhcp6_link,
+                                           &prefix,
+                                           pd_prefix_len,
+                                           lifetime_preferred,
+                                           lifetime_valid,
+                                           false);
+        }
+
+        HASHMAP_FOREACH(link, dhcp6_link->manager->links) {
+                if (link == dhcp6_link)
+                        continue;
+
+                r = dhcp6_pd_finalize(link);
+                if (r < 0)
+                        link_enter_failed(link);
+        }
+
+        return 0;
+}
+
+static int dhcp6_address_handler(sd_netlink *rtnl, sd_netlink_message *m, Link *link) {
+        int r;
+
+        assert(link);
+        assert(link->dhcp6_address_messages > 0);
+
+        link->dhcp6_address_messages--;
+
+        if (IN_SET(link->state, LINK_STATE_FAILED, LINK_STATE_LINGER))
+                return 1;
+
+        r = sd_netlink_message_get_errno(m);
+        if (r < 0 && r != -EEXIST) {
+                log_link_message_warning_errno(link, m, r, "Could not set DHCPv6 address");
+                link_enter_failed(link);
+                return 1;
+        } else if (r >= 0)
+                (void) manager_rtnl_process_address(rtnl, m, link->manager);
+
+        if (link->dhcp6_address_messages == 0) {
+                log_link_debug(link, "DHCPv6 addresses set");
+                link->dhcp6_address_configured = true;
+
+                r = dhcp6_remove_old(link, false);
+                if (r < 0) {
+                        link_enter_failed(link);
+                        return 1;
+                }
+
+                r = link_set_routes(link);
+                if (r < 0) {
+                        link_enter_failed(link);
+                        return 1;
+                }
+        }
+
+        return 1;
+}
+
+static int dhcp6_update_address(
+                Link *link,
+                const struct in6_addr *ip6_addr,
+                uint32_t lifetime_preferred,
+                uint32_t lifetime_valid) {
+
+        _cleanup_(address_freep) Address *addr = NULL;
+        _cleanup_free_ char *buffer = NULL;
+        Address *ret;
+        int r;
+
+        r = address_new(&addr);
+        if (r < 0)
+                return log_oom();
+
+        addr->family = AF_INET6;
+        addr->in_addr.in6 = *ip6_addr;
+        addr->flags = IFA_F_NOPREFIXROUTE;
+        addr->prefixlen = 128;
+        addr->cinfo.ifa_prefered = lifetime_preferred;
+        addr->cinfo.ifa_valid = lifetime_valid;
+
+        (void) in_addr_to_string(addr->family, &addr->in_addr, &buffer);
+        log_link_full(link, set_contains(link->dhcp6_addresses, addr) ? LOG_DEBUG : LOG_INFO,
+                      "DHCPv6 address %s/%u timeout preferred %d valid %d",
+                      strna(buffer), addr->prefixlen, lifetime_preferred, lifetime_valid);
+
+        r = address_configure(addr, link, dhcp6_address_handler, true, &ret);
+        if (r < 0)
+                return log_link_error_errno(link, r, "Failed to set DHCPv6 address %s/%u: %m",
+                                            strna(buffer), addr->prefixlen);
+
+        link->dhcp6_address_messages++;
+
+        r = set_ensure_put(&link->dhcp6_addresses, &address_hash_ops, ret);
+        if (r < 0)
+                return log_link_error_errno(link, r, "Failed to store DHCPv6 address %s/%u: %m",
+                                            strna(buffer), addr->prefixlen);
+
+        (void) set_remove(link->dhcp6_addresses_old, ret);
+
+        return 0;
+}
+
+static int dhcp6_address_acquired(Link *link) {
+        int r;
+
+        assert(link);
+        assert(link->dhcp6_lease);
+
+        for (sd_dhcp6_lease_reset_address_iter(link->dhcp6_lease);;) {
+                uint32_t lifetime_preferred, lifetime_valid;
+                struct in6_addr ip6_addr;
+
+                r = sd_dhcp6_lease_get_address(link->dhcp6_lease, &ip6_addr, &lifetime_preferred, &lifetime_valid);
+                if (r < 0)
+                        break;
+
+                r = dhcp6_update_address(link, &ip6_addr, lifetime_preferred, lifetime_valid);
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+static int dhcp6_lease_ip_acquired(sd_dhcp6_client *client, Link *link) {
+        _cleanup_(sd_dhcp6_lease_unrefp) sd_dhcp6_lease *lease_old = NULL;
+        sd_dhcp6_lease *lease;
+        Address *a;
+        Route *rt;
+        int r;
+
+        link->dhcp6_address_configured = false;
+        link->dhcp6_route_configured = false;
+
+        link_dirty(link);
+
+        while ((a = set_steal_first(link->dhcp6_addresses))) {
+                r = set_ensure_put(&link->dhcp6_addresses_old, &address_hash_ops, a);
+                if (r < 0)
+                        return log_link_error_errno(link, r, "Failed to store old DHCPv6 address: %m");
+        }
+
+        while ((rt = set_steal_first(link->dhcp6_routes))) {
+                r = set_ensure_put(&link->dhcp6_routes_old, &route_hash_ops, rt);
+                if (r < 0)
+                        return log_link_error_errno(link, r, "Failed to store old DHCPv6 route: %m");
+        }
+
+        r = sd_dhcp6_client_get_lease(client, &lease);
+        if (r < 0)
+                return log_link_error_errno(link, r, "Failed to get DHCPv6 lease: %m");
+
+        lease_old = TAKE_PTR(link->dhcp6_lease);
+        link->dhcp6_lease = sd_dhcp6_lease_ref(lease);
+
+        r = dhcp6_address_acquired(link);
+        if (r < 0)
+                return r;
+
+        if (dhcp6_lease_has_pd_prefix(lease)) {
+                r = dhcp6_pd_prefix_acquired(link);
+                if (r < 0)
+                        return r;
+        } else if (dhcp6_lease_has_pd_prefix(lease_old))
+                /* When we had PD prefixes but not now, we need to remove them. */
+                dhcp6_pd_prefix_lost(link);
+
+        if (link->dhcp6_address_messages == 0)
+                link->dhcp6_address_configured = true;
+        else {
+                log_link_debug(link, "Setting DHCPv6 addresses");
+                /* address_handler calls link_set_routes() and link_set_nexthop(). Before they are
+                 * called, the related flags must be cleared. Otherwise, the link becomes configured
+                 * state before routes are configured. */
+                link->static_routes_configured = false;
+                link->static_nexthops_configured = false;
+        }
+
+        if (link->dhcp6_route_messages == 0)
+                link->dhcp6_route_configured = true;
+        else
+                log_link_debug(link, "Setting unreachable routes for DHCPv6 delegated subnets");
+
+        r = dhcp6_remove_old(link, false);
+        if (r < 0)
+                return r;
+
+        if (link->dhcp6_address_configured && link->dhcp6_route_configured)
+                link_check_ready(link);
+        else
+                link_set_state(link, LINK_STATE_CONFIGURING);
+
+        return 0;
+}
+
+static int dhcp6_lease_information_acquired(sd_dhcp6_client *client, Link *link) {
+        return 0;
+}
+
+static int dhcp6_lease_lost(Link *link) {
+        int r;
+
+        assert(link);
+        assert(link->manager);
+
+        log_link_info(link, "DHCPv6 lease lost");
+
+        if (dhcp6_lease_has_pd_prefix(link->dhcp6_lease))
+                dhcp6_pd_prefix_lost(link);
+
+        link->dhcp6_lease = sd_dhcp6_lease_unref(link->dhcp6_lease);
+
+        r = dhcp6_remove(link);
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+static void dhcp6_handler(sd_dhcp6_client *client, int event, void *userdata) {
+        Link *link = userdata;
+        int r;
+
+        assert(link);
+        assert(link->network);
+
+        if (IN_SET(link->state, LINK_STATE_FAILED, LINK_STATE_LINGER))
+                return;
+
+        switch (event) {
+        case SD_DHCP6_CLIENT_EVENT_STOP:
+        case SD_DHCP6_CLIENT_EVENT_RESEND_EXPIRE:
+        case SD_DHCP6_CLIENT_EVENT_RETRANS_MAX:
+                r = dhcp6_lease_lost(link);
+                if (r < 0)
+                        link_enter_failed(link);
+                break;
+
+        case SD_DHCP6_CLIENT_EVENT_IP_ACQUIRE:
+                r = dhcp6_lease_ip_acquired(client, link);
+                if (r < 0) {
+                        link_enter_failed(link);
+                        return;
+                }
+
+                _fallthrough_;
+        case SD_DHCP6_CLIENT_EVENT_INFORMATION_REQUEST:
+                r = dhcp6_lease_information_acquired(client, link);
+                if (r < 0)
+                        link_enter_failed(link);
+                break;
+
+        default:
+                if (event < 0)
+                        log_link_warning_errno(link, event, "DHCPv6 error: %m");
+                else
+                        log_link_warning(link, "DHCPv6 unknown event: %d", event);
+                return;
+        }
+}
+
+int dhcp6_request_address(Link *link, int ir) {
+        int r, inf_req, pd;
+        bool running;
+
+        assert(link);
+        assert(link->dhcp6_client);
+        assert(link->network);
+        assert(in_addr_is_link_local(AF_INET6, (const union in_addr_union*) &link->ipv6ll_address) > 0);
+
+        r = sd_dhcp6_client_is_running(link->dhcp6_client);
+        if (r < 0)
+                return r;
+        running = r;
+
+        r = sd_dhcp6_client_get_prefix_delegation(link->dhcp6_client, &pd);
+        if (r < 0)
+                return r;
+
+        if (pd && ir && link->network->dhcp6_force_pd_other_information) {
+                log_link_debug(link, "Enabling managed mode to request DHCPv6 PD with 'Other Information' set");
+
+                r = sd_dhcp6_client_set_address_request(link->dhcp6_client, false);
+                if (r < 0)
+                        return r;
+
+                ir = false;
+        }
+
+        if (running) {
+                r = sd_dhcp6_client_get_information_request(link->dhcp6_client, &inf_req);
+                if (r < 0)
+                        return r;
+
+                if (inf_req == ir)
+                        return 0;
+
+                r = sd_dhcp6_client_stop(link->dhcp6_client);
+                if (r < 0)
+                        return r;
+        } else {
+                r = sd_dhcp6_client_set_local_address(link->dhcp6_client, &link->ipv6ll_address);
+                if (r < 0)
+                        return r;
+        }
+
+        r = sd_dhcp6_client_set_information_request(link->dhcp6_client, ir);
+        if (r < 0)
+                return r;
+
+        r = sd_dhcp6_client_start(link->dhcp6_client);
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+int dhcp6_request_prefix_delegation(Link *link) {
+        Link *l;
+
+        assert(link);
+        assert(link->manager);
+
+        if (!link_dhcp6_pd_is_enabled(link))
+                return 0;
+
+        log_link_debug(link, "Requesting DHCPv6 prefixes to be delegated for new link");
+
+        HASHMAP_FOREACH(l, link->manager->links) {
+                int r, enabled;
+
+                if (l == link)
+                        continue;
+
+                if (!l->dhcp6_client)
+                        continue;
+
+                r = sd_dhcp6_client_get_prefix_delegation(l->dhcp6_client, &enabled);
+                if (r < 0) {
+                        log_link_warning_errno(l, r, "Cannot get prefix delegation when adding new link: %m");
+                        link_enter_failed(l);
+                        continue;
+                }
+
+                if (enabled == 0) {
+                        r = sd_dhcp6_client_set_prefix_delegation(l->dhcp6_client, 1);
+                        if (r < 0) {
+                                log_link_warning_errno(l, r, "Cannot enable prefix delegation when adding new link: %m");
+                                link_enter_failed(l);
+                                continue;
+                        }
+                }
+
+                r = sd_dhcp6_client_is_running(l->dhcp6_client);
+                if (r <= 0)
+                        continue;
+
+                if (enabled != 0) {
+                        if (dhcp6_lease_has_pd_prefix(l->dhcp6_lease)) {
+                                log_link_debug(l, "Requesting re-assignment of delegated prefixes after adding new link");
+                                r = dhcp6_pd_prefix_acquired(l);
+                                if (r < 0)
+                                        link_enter_failed(l);
+                        }
+                        continue;
+                }
+
+                r = sd_dhcp6_client_stop(l->dhcp6_client);
+                if (r < 0) {
+                        log_link_warning_errno(l, r, "Cannot stop DHCPv6 prefix delegation client after adding new link: %m");
+                        link_enter_failed(l);
+                        continue;
+                }
+
+                r = sd_dhcp6_client_start(l->dhcp6_client);
+                if (r < 0) {
+                        log_link_warning_errno(l, r, "Cannot restart DHCPv6 prefix delegation client after adding new link: %m");
+                        link_enter_failed(l);
+                        continue;
+                }
+
+                log_link_debug(l, "Restarted DHCPv6 client to acquire prefix delegations after adding new link");
+        }
+
+        /* dhcp6_pd_prefix_acquired() may make the link in failed state. */
+        if (link->state == LINK_STATE_FAILED)
+                return -ENOANO;
+
+        return 0;
+}
+
+static int dhcp6_set_hostname(sd_dhcp6_client *client, Link *link) {
+        _cleanup_free_ char *hostname = NULL;
+        const char *hn;
+        int r;
+
+        assert(link);
+
+        if (!link->network->dhcp_send_hostname)
+                hn = NULL;
+        else if (link->network->dhcp_hostname)
+                hn = link->network->dhcp_hostname;
+        else {
+                r = gethostname_strict(&hostname);
+                if (r < 0 && r != -ENXIO) /* ENXIO: no hostname set or hostname is "localhost" */
+                        return r;
+
+                hn = hostname;
+        }
+
+        r = sd_dhcp6_client_set_fqdn(client, hn);
+        if (r == -EINVAL && hostname)
+                /* Ignore error when the machine's hostname is not suitable to send in DHCP packet. */
+                log_link_warning_errno(link, r, "DHCP6 CLIENT: Failed to set hostname from kernel hostname, ignoring: %m");
+        else if (r < 0)
+                return log_link_error_errno(link, r, "DHCP6 CLIENT: Failed to set hostname: %m");
+
+        return 0;
+}
+
+static bool dhcp6_enable_prefix_delegation(Link *dhcp6_link) {
+        Link *link;
+
+        assert(dhcp6_link);
+        assert(dhcp6_link->manager);
+
+        HASHMAP_FOREACH(link, dhcp6_link->manager->links) {
+                if (link == dhcp6_link)
+                        continue;
+
+                if (!link_dhcp6_pd_is_enabled(link))
+                        continue;
+
+                return true;
+        }
+
+        return false;
+}
+
+static int dhcp6_set_identifier(Link *link, sd_dhcp6_client *client) {
+        const DUID *duid;
+        int r;
+
+        assert(link);
+        assert(link->network);
+        assert(client);
+
+        r = sd_dhcp6_client_set_mac(client, link->hw_addr.addr.bytes, link->hw_addr.length, link->iftype);
+        if (r < 0)
+                return r;
+
+        if (link->network->iaid_set) {
+                r = sd_dhcp6_client_set_iaid(client, link->network->iaid);
+                if (r < 0)
+                        return r;
+        }
+
+        duid = link_get_duid(link);
+        if (duid->type == DUID_TYPE_LLT && duid->raw_data_len == 0)
+                r = sd_dhcp6_client_set_duid_llt(client, duid->llt_time);
+        else
+                r = sd_dhcp6_client_set_duid(client,
+                                             duid->type,
+                                             duid->raw_data_len > 0 ? duid->raw_data : NULL,
+                                             duid->raw_data_len);
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+int dhcp6_configure(Link *link) {
+        _cleanup_(sd_dhcp6_client_unrefp) sd_dhcp6_client *client = NULL;
+        sd_dhcp6_option *vendor_option;
+        sd_dhcp6_option *send_option;
+        void *request_options;
+        int r;
+
+        assert(link);
+        assert(link->network);
+
+        if (!link_dhcp6_enabled(link) && !link_ipv6_accept_ra_enabled(link))
+                return 0;
+
+        if (link->dhcp6_client)
+                return 0;
+
+        r = sd_dhcp6_client_new(&client);
+        if (r == -ENOMEM)
+                return log_oom();
+        if (r < 0)
+                return log_link_error_errno(link, r, "DHCP6 CLIENT: Failed to create DHCP6 client: %m");
+
+        r = sd_dhcp6_client_attach_event(client, link->manager->event, 0);
+        if (r < 0)
+                return log_link_error_errno(link, r, "DHCP6 CLIENT: Failed to attach event: %m");
+
+        r = dhcp6_set_identifier(link, client);
+        if (r < 0)
+                return log_link_error_errno(link, r, "DHCP6 CLIENT: Failed to set identifier: %m");
+
+        ORDERED_HASHMAP_FOREACH(send_option, link->network->dhcp6_client_send_options) {
+                r = sd_dhcp6_client_add_option(client, send_option);
+                if (r == -EEXIST)
+                        continue;
+                if (r < 0)
+                        return log_link_error_errno(link, r, "DHCP6 CLIENT: Failed to set option: %m");
+        }
+
+        r = dhcp6_set_hostname(client, link);
+        if (r < 0)
+                return r;
+
+        r = sd_dhcp6_client_set_ifindex(client, link->ifindex);
+        if (r < 0)
+                return log_link_error_errno(link, r, "DHCP6 CLIENT: Failed to set ifindex: %m");
+
+        if (link->network->dhcp6_rapid_commit) {
+                r = sd_dhcp6_client_set_request_option(client, SD_DHCP6_OPTION_RAPID_COMMIT);
+                if (r < 0)
+                        return log_link_error_errno(link, r, "DHCP6 CLIENT: Failed to set request flag for rapid commit: %m");
+        }
+
+        if (link->network->dhcp6_mudurl) {
+                r = sd_dhcp6_client_set_request_mud_url(client, link->network->dhcp6_mudurl);
+                if (r < 0)
+                        return log_link_error_errno(link, r, "DHCP6 CLIENT: Failed to set MUD URL: %m");
+        }
+
+        SET_FOREACH(request_options, link->network->dhcp6_request_options) {
+                uint32_t option = PTR_TO_UINT32(request_options);
+
+                r = sd_dhcp6_client_set_request_option(client, option);
+                if (r == -EEXIST) {
+                        log_link_debug(link, "DHCP6 CLIENT: Failed to set request flag for '%u' already exists, ignoring.", option);
+                        continue;
+                }
+                if (r < 0)
+                        return log_link_error_errno(link, r, "DHCP6 CLIENT: Failed to set request flag for '%u': %m", option);
+        }
+
+        if (link->network->dhcp6_user_class) {
+                r = sd_dhcp6_client_set_request_user_class(client, link->network->dhcp6_user_class);
+                if (r < 0)
+                        return log_link_error_errno(link, r, "DHCP6 CLIENT: Failed to set user class: %m");
+        }
+
+        if (link->network->dhcp6_vendor_class) {
+                r = sd_dhcp6_client_set_request_vendor_class(client, link->network->dhcp6_vendor_class);
+                if (r < 0)
+                        return log_link_error_errno(link, r, "DHCP6 CLIENT: Failed to set vendor class: %m");
+        }
+
+        ORDERED_HASHMAP_FOREACH(vendor_option, link->network->dhcp6_client_send_vendor_options) {
+                r = sd_dhcp6_client_add_vendor_option(client, vendor_option);
+                if (r == -EEXIST)
+                        continue;
+                if (r < 0)
+                        return log_link_error_errno(link, r, "DHCP6 CLIENT: Failed to set vendor option: %m");
+        }
+
+        r = sd_dhcp6_client_set_callback(client, dhcp6_handler, link);
+        if (r < 0)
+                return log_link_error_errno(link, r, "DHCP6 CLIENT: Failed to set callback: %m");
+
+        if (dhcp6_enable_prefix_delegation(link)) {
+                r = sd_dhcp6_client_set_prefix_delegation(client, true);
+                if (r < 0)
+                        return log_link_error_errno(link, r, "DHCP6 CLIENT: Failed to set prefix delegation: %m");
+        }
+
+        if (link->network->dhcp6_pd_length > 0) {
+                r = sd_dhcp6_client_set_prefix_delegation_hint(client, link->network->dhcp6_pd_length, &link->network->dhcp6_pd_address);
+                if (r < 0)
+                        return log_link_error_errno(link, r, "DHCP6 CLIENT: Failed to set prefix hint: %m");
+        }
+
+        link->dhcp6_client = TAKE_PTR(client);
+
+        return 0;
+}
+
+int dhcp6_update_mac(Link *link) {
+        bool restart;
+        int r;
+
+        assert(link);
+
+        if (!link->dhcp6_client)
+                return 0;
+
+        restart = sd_dhcp6_client_is_running(link->dhcp6_client) > 0;
+
+        if (restart) {
+                r = sd_dhcp6_client_stop(link->dhcp6_client);
+                if (r < 0)
+                        return r;
+        }
+
+        r = dhcp6_set_identifier(link, link->dhcp6_client);
+        if (r < 0)
+                return r;
+
+        if (restart) {
+                r = sd_dhcp6_client_start(link->dhcp6_client);
+                if (r < 0)
+                        return log_link_warning_errno(link, r, "Could not restart DHCPv6 client: %m");
+        }
+
+        return 0;
+}
+
+int link_serialize_dhcp6_client(Link *link, FILE *f) {
+        _cleanup_free_ char *duid = NULL;
+        uint32_t iaid;
+        int r;
+
+        assert(link);
+
+        if (!link->dhcp6_client)
+                return 0;
+
+        r = sd_dhcp6_client_get_iaid(link->dhcp6_client, &iaid);
+        if (r >= 0)
+                fprintf(f, "DHCP6_CLIENT_IAID=0x%x\n", iaid);
+
+        r = sd_dhcp6_client_duid_as_string(link->dhcp6_client, &duid);
+        if (r >= 0)
+                fprintf(f, "DHCP6_CLIENT_DUID=%s\n", duid);
+
+        return 0;
+}
+
+int config_parse_dhcp6_pd_hint(
+                const char* unit,
+                const char *filename,
+                unsigned line,
+                const char *section,
+                unsigned section_line,
+                const char *lvalue,
+                int ltype,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        Network *network = data;
+        int r;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+        assert(data);
+
+        r = in_addr_prefix_from_string(rvalue, AF_INET6, (union in_addr_union *) &network->dhcp6_pd_address, &network->dhcp6_pd_length);
+        if (r < 0) {
+                log_syntax(unit, LOG_WARNING, filename, line, r, "Failed to parse PrefixDelegationHint=%s, ignoring assignment", rvalue);
+                return 0;
+        }
+
+        if (network->dhcp6_pd_length < 1 || network->dhcp6_pd_length > 128) {
+                log_syntax(unit, LOG_WARNING, filename, line, 0, "Invalid prefix length='%d', ignoring assignment", network->dhcp6_pd_length);
+                network->dhcp6_pd_length = 0;
+                return 0;
+        }
+
+        return 0;
+}
+
+int config_parse_dhcp6_mud_url(
+                const char *unit,
+                const char *filename,
+                unsigned line,
+                const char *section,
+                unsigned section_line,
+                const char *lvalue,
+                int ltype,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        _cleanup_free_ char *unescaped = NULL;
+        Network *network = data;
+        int r;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+
+        if (isempty(rvalue)) {
+                network->dhcp6_mudurl = mfree(network->dhcp6_mudurl);
+                return 0;
+        }
+
+        r = cunescape(rvalue, 0, &unescaped);
+        if (r < 0) {
+                log_syntax(unit, LOG_WARNING, filename, line, r,
+                           "Failed to Failed to unescape MUD URL, ignoring: %s", rvalue);
+                return 0;
+        }
+
+        if (!http_url_is_valid(unescaped) || strlen(unescaped) > UINT8_MAX) {
+                log_syntax(unit, LOG_WARNING, filename, line, 0,
+                           "Failed to parse MUD URL '%s', ignoring: %m", rvalue);
+                return 0;
+        }
+
+        return free_and_replace(network->dhcp6_mudurl, unescaped);
+}
+
+DEFINE_CONFIG_PARSE_ENUM(config_parse_dhcp6_client_start_mode, dhcp6_client_start_mode, DHCP6ClientStartMode,
+                         "Failed to parse WithoutRA= setting");
+
+static const char* const dhcp6_client_start_mode_table[_DHCP6_CLIENT_START_MODE_MAX] = {
+        [DHCP6_CLIENT_START_MODE_NO]                  = "no",
+        [DHCP6_CLIENT_START_MODE_INFORMATION_REQUEST] = "information-request",
+        [DHCP6_CLIENT_START_MODE_SOLICIT]             = "solicit",
+};
+
+DEFINE_STRING_TABLE_LOOKUP(dhcp6_client_start_mode, DHCP6ClientStartMode);
+
+int config_parse_dhcp6_pd_subnet_id(
+                const char *unit,
+                const char *filename,
+                unsigned line,
+                const char *section,
+                unsigned section_line,
+                const char *lvalue,
+                int ltype,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        int64_t *p = data;
+        uint64_t t;
+        int r;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+        assert(data);
+
+        if (isempty(rvalue) || streq(rvalue, "auto")) {
+                *p = -1;
+                return 0;
+        }
+
+        r = safe_atoux64(rvalue, &t);
+        if (r < 0) {
+                log_syntax(unit, LOG_WARNING, filename, line, r,
+                           "Failed to parse %s=, ignoring assignment: %s",
+                           lvalue, rvalue);
+                return 0;
+        }
+        if (t > INT64_MAX) {
+                log_syntax(unit, LOG_WARNING, filename, line, 0,
+                           "Invalid subnet id '%s', ignoring assignment.",
+                           rvalue);
+                return 0;
+        }
+
+        *p = (int64_t) t;
+
+        return 0;
+}
+
+int config_parse_dhcp6_pd_token(
+                const char *unit,
+                const char *filename,
+                unsigned line,
+                const char *section,
+                unsigned section_line,
+                const char *lvalue,
+                int ltype,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        union in_addr_union *addr = data, tmp;
+        int r;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+        assert(data);
+
+        if (isempty(rvalue)) {
+                *addr = IN_ADDR_NULL;
+                return 0;
+        }
+
+        r = in_addr_from_string(AF_INET6, rvalue, &tmp);
+        if (r < 0) {
+                log_syntax(unit, LOG_WARNING, filename, line, r,
+                           "Failed to parse DHCPv6 Prefix Delegation token, ignoring: %s", rvalue);
+                return 0;
+        }
+
+        if (in_addr_is_null(AF_INET6, &tmp)) {
+                log_syntax(unit, LOG_WARNING, filename, line, 0,
+                           "DHCPv6 Prefix Delegation token cannot be the ANY address, ignoring: %s", rvalue);
+                return 0;
+        }
+
+        *addr = tmp;
+
+        return 0;
+}