From 0b3a7ca9d0797b2974bb421e0a5c2f08b90957aa Mon Sep 17 00:00:00 2001
From: Mary Strodl <ipadlover8322@gmail.com>
Date: Thu, 30 Jan 2025 16:00:20 -0500
Subject: [PATCH] ndisc: add support for PREF64 option

---
 src/core/ndisc/nm-lndp-ndisc.c    | 30 ++++++++++++++++++++++++++++++
 src/core/ndisc/nm-ndisc-private.h |  1 +
 src/core/ndisc/nm-ndisc.c         | 18 ++++++++++++++++++
 src/core/ndisc/nm-ndisc.h         | 10 ++++++++++
 4 files changed, 59 insertions(+)

diff --git a/src/core/ndisc/nm-lndp-ndisc.c b/src/core/ndisc/nm-lndp-ndisc.c
index c19dcc910b..980bc597bb 100644
--- a/src/core/ndisc/nm-lndp-ndisc.c
+++ b/src/core/ndisc/nm-lndp-ndisc.c
@@ -162,6 +162,7 @@ receive_ra(struct ndp *ndp, struct ndp_msg *msg, gpointer user_data)
     int                  offset;
     int                  hop_limit;
     guint32              val;
+    gboolean             pref64_found = FALSE;
 
     /* Router discovery is subject to the following RFC documents:
      *
@@ -401,6 +402,35 @@ receive_ra(struct ndp *ndp, struct ndp_msg *msg, gpointer user_data)
         }
     }
 
+    /* PREF64 */
+    ndp_msg_opt_for_each_offset (offset, msg, NDP_MSG_OPT_PREF64) {
+        struct in6_addr pref64_prefix = *ndp_msg_opt_pref64_prefix(msg, offset);
+        guint8          pref64_length = ndp_msg_opt_pref64_prefix_length(msg, offset);
+        gint64          expiry_msec =
+            _nm_ndisc_lifetime_to_expiry(now_msec, ndp_msg_opt_pref64_lifetime(msg, offset));
+
+        /* Currently, only /96 is supported */
+        if (pref64_length != 96) {
+            _LOGW("Ignored PREF64 for unsupported prefix length: %d (only /96 is supported)",
+                  pref64_length);
+            continue;
+        }
+
+        /* Newer RA has more up to date information, prefer it: */
+        if (!pref64_found) {
+            pref64_found                     = TRUE;
+            rdata->public.pref64.expiry_msec = 0;
+        }
+
+        if (expiry_msec >= rdata->public.pref64.expiry_msec) {
+            rdata->public.pref64.network     = pref64_prefix;
+            rdata->public.pref64.expiry_msec = expiry_msec;
+            rdata->public.pref64.plen        = pref64_length;
+            rdata->public.pref64.valid       = TRUE;
+            changed |= NM_NDISC_CONFIG_PREF64;
+        }
+    }
+
     nm_ndisc_ra_received(ndisc, now_msec, changed);
     return 0;
 }
diff --git a/src/core/ndisc/nm-ndisc-private.h b/src/core/ndisc/nm-ndisc-private.h
index 1479e5666e..697700eb26 100644
--- a/src/core/ndisc/nm-ndisc-private.h
+++ b/src/core/ndisc/nm-ndisc-private.h
@@ -14,6 +14,7 @@ struct _NMNDiscDataInternal {
     NMNDiscData public;
     GArray *gateways;
     GArray *addresses;
+    GArray *clat_addresses;
     GArray *routes;
     GArray *dns_servers;
     GArray *dns_domains;
diff --git a/src/core/ndisc/nm-ndisc.c b/src/core/ndisc/nm-ndisc.c
index 758ce0a05c..dfe190e572 100644
--- a/src/core/ndisc/nm-ndisc.c
+++ b/src/core/ndisc/nm-ndisc.c
@@ -212,6 +212,12 @@ nm_ndisc_data_to_l3cd(NMDedupMultiIndex        *multi_idx,
     for (i = 0; i < rdata->dns_domains_n; i++)
         nm_l3_config_data_add_search(l3cd, AF_INET6, rdata->dns_domains[i].domain);
 
+    if (rdata->pref64.valid) {
+        nm_l3_config_data_set_pref64(l3cd, rdata->pref64.network, rdata->pref64.plen);
+    } else {
+        nm_l3_config_data_set_pref64_valid(l3cd, FALSE);
+    }
+
     nm_l3_config_data_set_ndisc_hop_limit(l3cd, rdata->hop_limit);
     nm_l3_config_data_set_ndisc_reachable_time_msec(l3cd, rdata->reachable_time_ms);
     nm_l3_config_data_set_ndisc_retrans_timer_msec(l3cd, rdata->retrans_timer_ms);
@@ -1528,6 +1534,17 @@ clean_routes(NMNDisc *ndisc, gint64 now_msec, NMNDiscConfigMap *changed, gint64
         *changed |= NM_NDISC_CONFIG_ROUTES;
 }
 
+static void
+clean_pref64(NMNDisc *ndisc, gint64 now_msec, NMNDiscConfigMap *changed, gint64 *next_msec)
+{
+    NMNDiscDataInternal *rdata = &NM_NDISC_GET_PRIVATE(ndisc)->rdata;
+
+    if (!rdata->public.pref64.valid)
+        return;
+    if (!expiry_next(now_msec, rdata->public.pref64.expiry_msec, next_msec))
+        *changed |= NM_NDISC_CONFIG_PREF64;
+}
+
 static void
 clean_dns_servers(NMNDisc *ndisc, gint64 now_msec, NMNDiscConfigMap *changed, gint64 *next_msec)
 {
@@ -1604,6 +1621,7 @@ check_timestamps(NMNDisc *ndisc, gint64 now_msec, NMNDiscConfigMap changed)
     clean_gateways(ndisc, now_msec, &changed, &next_msec);
     clean_addresses(ndisc, now_msec, &changed, &next_msec);
     clean_routes(ndisc, now_msec, &changed, &next_msec);
+    clean_pref64(ndisc, now_msec, &changed, &next_msec);
     clean_dns_servers(ndisc, now_msec, &changed, &next_msec);
     clean_dns_domains(ndisc, now_msec, &changed, &next_msec);
 
diff --git a/src/core/ndisc/nm-ndisc.h b/src/core/ndisc/nm-ndisc.h
index eda1e696d9..416c319117 100644
--- a/src/core/ndisc/nm-ndisc.h
+++ b/src/core/ndisc/nm-ndisc.h
@@ -119,6 +119,13 @@ typedef struct _NMNDiscRoute {
     bool               duplicate : 1;
 } NMNDiscRoute;
 
+typedef struct _NMNDiscPref64 {
+    struct in6_addr network;
+    gint64          expiry_msec;
+    guint8          plen;
+    bool            valid : 1;
+} NMNDiscPref64;
+
 typedef struct {
     struct in6_addr address;
     gint64          expiry_msec;
@@ -141,6 +148,7 @@ typedef enum {
     NM_NDISC_CONFIG_MTU            = 1 << 7,
     NM_NDISC_CONFIG_REACHABLE_TIME = 1 << 8,
     NM_NDISC_CONFIG_RETRANS_TIMER  = 1 << 9,
+    NM_NDISC_CONFIG_PREF64         = 1 << 10,
 } NMNDiscConfigMap;
 
 typedef enum {
@@ -196,6 +204,8 @@ typedef struct {
     const NMNDiscRoute     *routes;
     const NMNDiscDNSServer *dns_servers;
     const NMNDiscDNSDomain *dns_domains;
+
+    NMNDiscPref64 pref64;
 } NMNDiscData;
 
 /**