Merge pull request #19852 from yuwata/network-stable-secret

network: introduce IPv6StableSecretAddress= to configure secret key for generating IPv6LL address

diff --cc src/network/networkd-setlink.c
Simple merge

diff --cc src/network/networkd-sysctl.c
index a67e10e8125159f81f77b0a291de7ba066aa0bce,e3e2c0c7a15bb5938abe90e2cc266704c6972b68..6c7a606dfb572df88947438f7a2ac3c9da90a41f
--- 1/src/network/networkd-sysctl.c
--- 2/src/network/networkd-sysctl.c
+++ b/src/network/networkd-sysctl.c
@@@ -201,16 -202,51 +204,58 @@@ int link_set_ipv6_mtu(Link *link) 
          if (link->network->ipv6_mtu == 0)
                  return 0;
  
 -        return sysctl_write_ip_property_uint32(AF_INET6, link->ifname, "mtu", link->network->ipv6_mtu);
 +        mtu = link->network->ipv6_mtu;
 +        if (mtu > link->max_mtu) {
 +                log_link_warning(link, "Reducing requested IPv6 MTU %"PRIu32" to the interface's maximum MTU %"PRIu32".",
 +                                 mtu, link->max_mtu);
 +                mtu = link->max_mtu;
 +        }
 +
 +        return sysctl_write_ip_property_uint32(AF_INET6, link->ifname, "mtu", mtu);
  }
  
+ static int link_set_ipv6ll_stable_secret(Link *link) {
+         _cleanup_free_ char *str = NULL;
+         struct in6_addr a;
+         int r;
+ 
+         assert(link);
+         assert(link->network);
+ 
+         if (link->network->ipv6ll_address_gen_mode != IPV6_LINK_LOCAL_ADDRESSS_GEN_MODE_STABLE_PRIVACY)
+                 return 0;
+ 
+         if (in6_addr_is_set(&link->network->ipv6ll_stable_secret))
+                 a = link->network->ipv6ll_stable_secret;
+         else {
+                 sd_id128_t key;
+                 le64_t v;
+ 
+                 /* Generate a stable secret address from machine-ID and the interface name. */
+ 
+                 r = sd_id128_get_machine_app_specific(STABLE_SECRET_APP_ID_1, &key);
+                 if (r < 0)
+                         return log_link_debug_errno(link, r, "Failed to generate key: %m");
+ 
+                 v = htole64(siphash24_string(link->ifname, key.bytes));
+                 memcpy(a.s6_addr, &v, sizeof(v));
+ 
+                 r = sd_id128_get_machine_app_specific(STABLE_SECRET_APP_ID_2, &key);
+                 if (r < 0)
+                         return log_link_debug_errno(link, r, "Failed to generate key: %m");
+ 
+                 v = htole64(siphash24_string(link->ifname, key.bytes));
+                 assert_cc(sizeof(v) * 2 == sizeof(a.s6_addr));
+                 memcpy(a.s6_addr + sizeof(v), &v, sizeof(v));
+         }
+ 
+         r = in6_addr_to_string(&a, &str);
+         if (r < 0)
+                 return r;
+ 
+         return sysctl_write_ip_property(AF_INET6, link->ifname, "stable_secret", str);
+ }
+ 
  static int link_set_ipv4_accept_local(Link *link) {
          assert(link);