From e693e969614062fea1746399cf5cff4c09526c6a Mon Sep 17 00:00:00 2001
From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Fri, 24 Sep 2021 15:00:43 +0900
Subject: [PATCH] sd-dhcp6-client: do not merge NTP and SNTP options

Previously, SNTP option is ignored when it appears after NTP option(s),
but merged later NTP options when it appears first.
This makes split the NTP and SNTP addresses, and use SNTP addresses only
when no NTP option is provided.
---
 src/libsystemd-network/dhcp6-lease-internal.h |  4 ++-
 src/libsystemd-network/sd-dhcp6-client.c      |  2 +-
 src/libsystemd-network/sd-dhcp6-lease.c       | 26 +++++++++++--------
 src/libsystemd-network/test-dhcp6-client.c    |  3 +--
 4 files changed, 20 insertions(+), 15 deletions(-)

diff --git a/src/libsystemd-network/dhcp6-lease-internal.h b/src/libsystemd-network/dhcp6-lease-internal.h
index 8584336341..562fce3d3a 100644
--- a/src/libsystemd-network/dhcp6-lease-internal.h
+++ b/src/libsystemd-network/dhcp6-lease-internal.h
@@ -31,6 +31,8 @@ struct sd_dhcp6_lease {
         struct in6_addr *ntp;
         size_t ntp_count;
         char **ntp_fqdn;
+        struct in6_addr *sntp;
+        size_t sntp_count;
         char *fqdn;
 };
 
@@ -51,7 +53,7 @@ int dhcp6_lease_get_pd_iaid(sd_dhcp6_lease *lease, be32_t *iaid);
 int dhcp6_lease_set_dns(sd_dhcp6_lease *lease, const uint8_t *optval, size_t optlen);
 int dhcp6_lease_add_domains(sd_dhcp6_lease *lease, const uint8_t *optval, size_t optlen);
 int dhcp6_lease_add_ntp(sd_dhcp6_lease *lease, const uint8_t *optval, size_t optlen);
-int dhcp6_lease_set_sntp(sd_dhcp6_lease *lease, const uint8_t *optval, size_t optlen) ;
+int dhcp6_lease_add_sntp(sd_dhcp6_lease *lease, const uint8_t *optval, size_t optlen) ;
 int dhcp6_lease_set_fqdn(sd_dhcp6_lease *lease, const uint8_t *optval, size_t optlen);
 
 int dhcp6_lease_new(sd_dhcp6_lease **ret);
diff --git a/src/libsystemd-network/sd-dhcp6-client.c b/src/libsystemd-network/sd-dhcp6-client.c
index 1564ebee73..d7c29d3e58 100644
--- a/src/libsystemd-network/sd-dhcp6-client.c
+++ b/src/libsystemd-network/sd-dhcp6-client.c
@@ -1264,7 +1264,7 @@ static int client_parse_message(
                         break;
 
                 case SD_DHCP6_OPTION_SNTP_SERVERS:
-                        r = dhcp6_lease_set_sntp(lease, optval, optlen);
+                        r = dhcp6_lease_add_sntp(lease, optval, optlen);
                         if (r < 0)
                                 return r;
 
diff --git a/src/libsystemd-network/sd-dhcp6-lease.c b/src/libsystemd-network/sd-dhcp6-lease.c
index 7c9d421a94..7dc4286a45 100644
--- a/src/libsystemd-network/sd-dhcp6-lease.c
+++ b/src/libsystemd-network/sd-dhcp6-lease.c
@@ -290,30 +290,33 @@ int dhcp6_lease_add_ntp(sd_dhcp6_lease *lease, const uint8_t *optval, size_t opt
         return 0;
 }
 
-int dhcp6_lease_set_sntp(sd_dhcp6_lease *lease, const uint8_t *optval, size_t optlen) {
+int dhcp6_lease_add_sntp(sd_dhcp6_lease *lease, const uint8_t *optval, size_t optlen) {
         assert_return(lease, -EINVAL);
         assert_return(optval, -EINVAL);
 
         if (optlen == 0)
                 return 0;
 
-        if (lease->ntp || lease->ntp_fqdn)
-                return -EEXIST;
-
-        /* Using deprecated SNTP information */
-
-        return dhcp6_option_parse_addresses(optval, optlen, &lease->ntp, &lease->ntp_count);
+        /* SNTP option is defined in RFC4075, and deprecated by RFC5908. */
+        return dhcp6_option_parse_addresses(optval, optlen, &lease->sntp, &lease->sntp_count);
 }
 
 int sd_dhcp6_lease_get_ntp_addrs(sd_dhcp6_lease *lease, const struct in6_addr **ret) {
         assert_return(lease, -EINVAL);
         assert_return(ret, -EINVAL);
 
-        if (!lease->ntp)
-                return -ENOENT;
+        if (lease->ntp) {
+                *ret = lease->ntp;
+                return lease->ntp_count;
+        }
 
-        *ret = lease->ntp;
-        return lease->ntp_count;
+        if (lease->sntp && !lease->ntp_fqdn) {
+                /* Fallback to the deprecated SNTP option. */
+                *ret = lease->sntp;
+                return lease->sntp_count;
+        }
+
+        return -ENOENT;
 }
 
 int sd_dhcp6_lease_get_ntp_fqdn(sd_dhcp6_lease *lease, char ***ret) {
@@ -369,6 +372,7 @@ static sd_dhcp6_lease *dhcp6_lease_free(sd_dhcp6_lease *lease) {
         strv_free(lease->domains);
         free(lease->ntp);
         strv_free(lease->ntp_fqdn);
+        free(lease->sntp);
 
         return mfree(lease);
 }
diff --git a/src/libsystemd-network/test-dhcp6-client.c b/src/libsystemd-network/test-dhcp6-client.c
index 665000ef45..64b51f1232 100644
--- a/src/libsystemd-network/test-dhcp6-client.c
+++ b/src/libsystemd-network/test-dhcp6-client.c
@@ -521,8 +521,7 @@ static int test_advertise_option(sd_event *e) {
 
                 case SD_DHCP6_OPTION_SNTP_SERVERS:
                         assert_se(optlen == 16);
-                        assert_se(dhcp6_lease_set_sntp(lease, optval,
-                                                       optlen) >= 0);
+                        assert_se(dhcp6_lease_add_sntp(lease, optval, optlen) >= 0);
                         break;
 
                 default: