Fix calculation of preferred and valid times

[odhcp6c.git] / src / dhcpv6.c

diff --git a/src/dhcpv6.c b/src/dhcpv6.c
index 93433d4d59ce5e4b945fec9904e6d4d3feba5057..28fad507b4a4fa39e541c01f1e6091bed255f491 100644 (file)
--- a/src/dhcpv6.c
+++ b/src/dhcpv6.c
@@ -614,20 +614,24 @@ static int dhcpv6_handle_reply(_unused enum dhcpv6_msg orig,
        dhcpv6_for_each_option(ia_pd, ia_pd + ia_pd_len, otype, olen, odata) {
                struct dhcpv6_ia_prefix *p = (void*)&odata[-4];
                uint32_t valid = ntohl(p->valid);
-               p->valid = (valid < elapsed) ? 0 : htonl(valid - elapsed);
+               if (valid != UINT32_MAX)
+                       p->valid = (valid < elapsed) ? 0 : htonl(valid - elapsed);
 
                uint32_t pref = ntohl(p->preferred);
-               p->preferred = (pref < elapsed) ? 0 : htonl(pref - elapsed);
+               if (pref != UINT32_MAX)
+                       p->preferred = (pref < elapsed) ? 0 : htonl(pref - elapsed);
        }
 
        // Decrease valid and preferred lifetime of addresses
        dhcpv6_for_each_option(ia_na, ia_na + ia_na_len, otype, olen, odata) {
                struct dhcpv6_ia_addr *p = (void*)&odata[-4];
                uint32_t valid = ntohl(p->valid);
-               p->valid = (valid < elapsed) ? 0 : htonl(valid - elapsed);
+               if (valid != UINT32_MAX)
+                       p->valid = (valid < elapsed) ? 0 : htonl(valid - elapsed);
 
                uint32_t pref = ntohl(p->preferred);
-               p->preferred = (pref < elapsed) ? 0 : htonl(pref - elapsed);
+               if (pref != UINT32_MAX)
+                       p->preferred = (pref < elapsed) ? 0 : htonl(pref - elapsed);
        }
 
        // Parse and find all matching IAs