Avoid solicit for zero-length prefix

diff --git a/src/dhcpv6.c b/src/dhcpv6.c
index 760f2359a112e715330a5bc309261da0540193c7..a3e0a18e50ec1644b07110e371ac52bd6283ce27 100644 (file)
--- a/src/dhcpv6.c
+++ b/src/dhcpv6.c
@@ -272,17 +272,21 @@ static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
                for (size_t i = 0; i < n_prefixes; i++) {
                        struct dhcpv6_ia_hdr hdr_ia_pd = {
                                htons(DHCPV6_OPT_IA_PD),
-                               htons(sizeof(hdr_ia_pd) - 4 + sizeof(struct dhcpv6_ia_prefix)),
+                               htons(sizeof(hdr_ia_pd) - 4 +
+                                     sizeof(struct dhcpv6_ia_prefix) * !!request_prefixes[i].length),
                                request_prefixes[i].iaid, 0, 0
                        };
                        struct dhcpv6_ia_prefix pref = {
                                .type = htons(DHCPV6_OPT_IA_PREFIX),
-                               .len = htons(25), .prefix = request_prefixes[i].length
+                               .len = htons(sizeof(pref) - 4),
+                               .prefix = request_prefixes[i].length
                        };
                        memcpy(ia_pd + ia_pd_len, &hdr_ia_pd, sizeof(hdr_ia_pd));
                        ia_pd_len += sizeof(hdr_ia_pd);
-                       memcpy(ia_pd + ia_pd_len, &pref, sizeof(pref));
-                       ia_pd_len += sizeof(pref);
+                       if (request_prefixes[i].length) {
+                               memcpy(ia_pd + ia_pd_len, &pref, sizeof(pref));
+                               ia_pd_len += sizeof(pref);
+                       }
                }
        } else {
                struct odhcp6c_entry *e = odhcp6c_get_state(STATE_IA_PD, &ia_pd_entries);