dhcpv6: assign all viable DHCPv6 addresses by default (FS#402, FS#524)
[project/odhcpd.git] / src / dhcpv6-ia.c
index 888634f..847ede4 100644 (file)
@@ -16,8 +16,6 @@
 #include "odhcpd.h"
 #include "dhcpv6.h"
 #include "dhcpv4.h"
-#include "libubox/md5.h"
-#include "libubox/usock.h"
 
 #include <time.h>
 #include <errno.h>
 #include <arpa/inet.h>
 #include <sys/timerfd.h>
 
+#include <libubox/md5.h>
+#include <libubox/usock.h>
+
 #define ADDR_ENTRY_VALID_IA_ADDR(iface, i, m, addrs) \
-    ((iface)->managed == RELAYD_MANAGED_NO_AFLAG || (i) == (m) || \
+    ((iface)->dhcpv6_assignall || (i) == (m) || \
      (addrs)[(i)].prefix > 64)
 
 static void free_dhcpv6_assignment(struct dhcpv6_assignment *c);
@@ -155,14 +156,14 @@ static inline bool valid_addr(const struct odhcpd_ipaddr *addr, time_t now)
        return (addr->prefix <= 96 && addr->preferred > (uint32_t)now);
 }
 
-static size_t elect_addr(const struct odhcpd_ipaddr *addrs, const size_t addrlen)
+static size_t get_preferred_addr(const struct odhcpd_ipaddr *addrs, const size_t addrlen)
 {
        size_t i, m;
 
        for (i = 0, m = 0; i < addrlen; ++i) {
                if (addrs[i].preferred > addrs[m].preferred ||
-                       (addrs[i].preferred == addrs[m].preferred &&
-                        memcmp(&addrs[i].addr, &addrs[m].addr, 16) > 0))
+                               (addrs[i].preferred == addrs[m].preferred &&
+                               memcmp(&addrs[i].addr, &addrs[m].addr, 16) > 0))
                        m = i;
        }
 
@@ -232,146 +233,196 @@ static int send_reconf(struct interface *iface, struct dhcpv6_assignment *assign
        return odhcpd_send(iface->dhcpv6_event.uloop.fd, &assign->peer, &iov, 1, iface);
 }
 
-void dhcpv6_write_statefile(void)
+void dhcpv6_enum_ia_addrs(struct interface *iface, struct dhcpv6_assignment *c,
+                               time_t now, dhcpv6_binding_cb_handler_t func, void *arg)
 {
+       struct odhcpd_ipaddr *addrs = (c->managed) ? c->managed : iface->ia_addr;
+       size_t addrlen = (c->managed) ? (size_t)c->managed_size : iface->ia_addr_len;
+       size_t m = get_preferred_addr(addrs, addrlen);
+
+       for (size_t i = 0; i < addrlen; ++i) {
+               struct in6_addr addr;
+               uint32_t pref, valid;
+               int prefix = c->managed ? addrs[i].prefix : c->length;
+
+               if (!valid_addr(&addrs[i], now))
+                       continue;
+
+               addr = addrs[i].addr.in6;
+               pref = addrs[i].preferred;
+               valid = addrs[i].valid;
+               if (prefix == 128) {
+                       if (!ADDR_ENTRY_VALID_IA_ADDR(iface, i, m, addrs))
+                               continue;
+
+                       addr.s6_addr32[3] = htonl(c->assigned);
+               } else {
+                       if (!valid_prefix_length(c, addrs[i].prefix))
+                               continue;
+
+                       addr.s6_addr32[1] |= htonl(c->assigned);
+                       addr.s6_addr32[2] = addr.s6_addr32[3] = 0;
+               }
+
+               if (pref != UINT32_MAX)
+                       pref -= now;
+
+               if (valid != UINT32_MAX)
+                       valid -= now;
+
+               func(&addr, prefix, pref, valid, arg);
+       }
+}
+
+struct write_ctxt {
+       FILE *fp;
        md5_ctx_t md5;
-       md5_begin(&md5);
+       struct dhcpv6_assignment *c;
+       struct interface *iface;
+       char *buf;
+       int buf_len;
+       int buf_idx;
+};
+
+void dhcpv6_write_ia_addr(struct in6_addr *addr, int prefix, _unused uint32_t pref,
+                               _unused uint32_t valid, void *arg)
+{
+       struct write_ctxt *ctxt = (struct write_ctxt *)arg;
+       char ipbuf[INET6_ADDRSTRLEN];
+
+       inet_ntop(AF_INET6, addr, ipbuf, sizeof(ipbuf) - 1);
+
+       if (ctxt->c->length == 128 && ctxt->c->hostname) {
+               fputs(ipbuf, ctxt->fp);
+
+               char b[256];
+               if (dn_expand(ctxt->iface->search, ctxt->iface->search + ctxt->iface->search_len,
+                               ctxt->iface->search, b, sizeof(b)) > 0)
+                       fprintf(ctxt->fp, "\t%s.%s", ctxt->c->hostname, b);
+
+               fprintf(ctxt->fp, "\t%s\n", ctxt->c->hostname);
+               md5_hash(ipbuf, strlen(ipbuf), &ctxt->md5);
+               md5_hash(ctxt->c->hostname, strlen(ctxt->c->hostname), &ctxt->md5);
+       }
+
+       ctxt->buf_idx += snprintf(ctxt->buf + ctxt->buf_idx,ctxt->buf_len - ctxt->buf_idx,
+                                       "%s/%d ", ipbuf, prefix);
+}
+
+void dhcpv6_write_statefile(void)
+{
+       struct write_ctxt ctxt;
+
+       md5_begin(&ctxt.md5);
 
        if (config.dhcp_statefile) {
                time_t now = odhcpd_time(), wall_time = time(NULL);
                int fd = open(config.dhcp_statefile, O_CREAT | O_WRONLY | O_CLOEXEC, 0644);
+               char leasebuf[512];
+
                if (fd < 0)
                        return;
-
-               lockf(fd, F_LOCK, 0);
+               int ret;
+               ret = lockf(fd, F_LOCK, 0);
+               if (ret < 0) {
+                       close(fd);
+                       return;
+               }
                if (ftruncate(fd, 0) < 0) {}
 
-               FILE *fp = fdopen(fd, "w");
-               if (!fp) {
+               ctxt.fp = fdopen(fd, "w");
+               if (!ctxt.fp) {
                        close(fd);
                        return;
                }
 
-               struct interface *iface;
-               list_for_each_entry(iface, &interfaces, head) {
-                       if (iface->dhcpv6 != RELAYD_SERVER && iface->dhcpv4 != RELAYD_SERVER)
+               ctxt.buf = leasebuf;
+               ctxt.buf_len = sizeof(leasebuf);
+
+               list_for_each_entry(ctxt.iface, &interfaces, head) {
+                       if (ctxt.iface->dhcpv6 != RELAYD_SERVER &&
+                                       ctxt.iface->dhcpv4 != RELAYD_SERVER)
                                continue;
 
-                       if (iface->dhcpv6 == RELAYD_SERVER && iface->ia_assignments.next) {
-                               struct dhcpv6_assignment *c;
-                               list_for_each_entry(c, &iface->ia_assignments, head) {
-                                       if (!(c->flags & OAF_BOUND) || c->managed_size < 0)
+                       if (ctxt.iface->dhcpv6 == RELAYD_SERVER &&
+                                       ctxt.iface->ia_assignments.next) {
+                               list_for_each_entry(ctxt.c, &ctxt.iface->ia_assignments, head) {
+                                       if (!(ctxt.c->flags & OAF_BOUND) || ctxt.c->managed_size < 0)
                                                continue;
 
-                                       char ipbuf[INET6_ADDRSTRLEN];
-                                       char leasebuf[512];
                                        char duidbuf[264];
-                                       odhcpd_hexlify(duidbuf, c->clid_data, c->clid_len);
-
-                                       /* iface DUID iaid hostname lifetime assigned length [addrs...] */
-                                       int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s %x %s %ld %x %u ",
-                                                       iface->ifname, duidbuf, ntohl(c->iaid),
-                                                       (c->hostname ? c->hostname : "-"),
-                                                       (c->valid_until > now ?
-                                                               (c->valid_until - now + wall_time) :
-                                                               (INFINITE_VALID(c->valid_until) ? -1 : 0)),
-                                                       c->assigned, (unsigned)c->length);
-
-                                       struct in6_addr addr;
-                                       struct odhcpd_ipaddr *addrs = (c->managed) ? c->managed : iface->ia_addr;
-                                       size_t addrlen = (c->managed) ? (size_t)c->managed_size : iface->ia_addr_len;
-                                       size_t m = elect_addr(addrs, addrlen);
 
-                                       for (size_t i = 0; i < addrlen; ++i) {
-                                               if (!valid_addr(&addrs[i], now) ||
-                                                           (!INFINITE_VALID(c->valid_until) && c->valid_until <= now))
-                                                       continue;
+                                       odhcpd_hexlify(duidbuf, ctxt.c->clid_data, ctxt.c->clid_len);
 
-                                               addr = addrs[i].addr;
-                                               if (c->length == 128) {
-                                                       if (!ADDR_ENTRY_VALID_IA_ADDR(iface, i, m, addrs))
-                                                               continue;
-
-                                                       addr.s6_addr32[3] = htonl(c->assigned);
-                                               }
-                                               else {
-                                                       if (!valid_prefix_length(c, addrs[i].prefix))
-                                                               continue;
-
-                                                       addr.s6_addr32[1] |= htonl(c->assigned);
-                                               }
-
-                                               inet_ntop(AF_INET6, &addr, ipbuf, sizeof(ipbuf) - 1);
-
-                                               if (c->length == 128 && c->hostname) {
-                                                       fputs(ipbuf, fp);
-
-                                                       char b[256];
-                                                       if (dn_expand(iface->search, iface->search + iface->search_len,
-                                                                       iface->search, b, sizeof(b)) > 0)
-                                                               fprintf(fp, "\t%s.%s", c->hostname, b);
-
-                                                       fprintf(fp, "\t%s\n", c->hostname);
-                                                       md5_hash(ipbuf, strlen(ipbuf), &md5);
-                                                       md5_hash(c->hostname, strlen(c->hostname), &md5);
-                                               }
-
-                                               l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/%d ", ipbuf,
-                                                               (c->managed_size) ? addrs[i].prefix : c->length);
-                                       }
-                                       leasebuf[l - 1] = '\n';
-                                       fwrite(leasebuf, 1, l, fp);
+                                       /* iface DUID iaid hostname lifetime assigned length [addrs...] */
+                                       ctxt.buf_idx = snprintf(ctxt.buf, ctxt.buf_len, "# %s %s %x %s %ld %x %u ",
+                                                               ctxt.iface->ifname, duidbuf, ntohl(ctxt.c->iaid),
+                                                               (ctxt.c->hostname ? ctxt.c->hostname : "-"),
+                                                               (ctxt.c->valid_until > now ?
+                                                                       (ctxt.c->valid_until - now + wall_time) :
+                                                                       (INFINITE_VALID(ctxt.c->valid_until) ? -1 : 0)),
+                                                               ctxt.c->assigned, (unsigned)ctxt.c->length);
+
+                                       if (INFINITE_VALID(ctxt.c->valid_until) || ctxt.c->valid_until > now)
+                                               dhcpv6_enum_ia_addrs(ctxt.iface, ctxt.c, now,
+                                                                       dhcpv6_write_ia_addr, &ctxt);
+
+                                       ctxt.buf[ctxt.buf_idx - 1] = '\n';
+                                       fwrite(ctxt.buf, 1, ctxt.buf_idx, ctxt.fp);
                                }
                        }
 
-                       if (iface->dhcpv4 == RELAYD_SERVER && iface->dhcpv4_assignments.next) {
+                       if (ctxt.iface->dhcpv4 == RELAYD_SERVER &&
+                                       ctxt.iface->dhcpv4_assignments.next) {
                                struct dhcpv4_assignment *c;
-                               list_for_each_entry(c, &iface->dhcpv4_assignments, head) {
+                               list_for_each_entry(c, &ctxt.iface->dhcpv4_assignments, head) {
                                        if (!(c->flags & OAF_BOUND))
                                                continue;
 
                                        char ipbuf[INET6_ADDRSTRLEN];
-                                       char leasebuf[512];
                                        char duidbuf[16];
                                        odhcpd_hexlify(duidbuf, c->hwaddr, sizeof(c->hwaddr));
 
                                        /* iface DUID iaid hostname lifetime assigned length [addrs...] */
-                                       int l = snprintf(leasebuf, sizeof(leasebuf), "# %s %s ipv4 %s %ld %x 32 ",
-                                                       iface->ifname, duidbuf,
-                                                       (c->hostname ? c->hostname : "-"),
-                                                       (c->valid_until > now ?
-                                                               (c->valid_until - now + wall_time) :
-                                                               (INFINITE_VALID(c->valid_until) ? -1 : 0)),
-                                                       c->addr);
+                                       ctxt.buf_idx = snprintf(ctxt.buf, ctxt.buf_len, "# %s %s ipv4 %s %ld %x 32 ",
+                                                               ctxt.iface->ifname, duidbuf,
+                                                               (c->hostname ? c->hostname : "-"),
+                                                               (c->valid_until > now ?
+                                                                       (c->valid_until - now + wall_time) :
+                                                                       (INFINITE_VALID(c->valid_until) ? -1 : 0)),
+                                                               c->addr);
 
                                        struct in_addr addr = {htonl(c->addr)};
                                        inet_ntop(AF_INET, &addr, ipbuf, sizeof(ipbuf) - 1);
 
                                        if (c->hostname) {
-                                               fputs(ipbuf, fp);
+                                               fputs(ipbuf, ctxt.fp);
 
                                                char b[256];
-                                               if (dn_expand(iface->search, iface->search + iface->search_len,
-                                                               iface->search, b, sizeof(b)) > 0)
-                                                       fprintf(fp, "\t%s.%s", c->hostname, b);
-
-                                               fprintf(fp, "\t%s\n", c->hostname);
-                                               md5_hash(ipbuf, strlen(ipbuf), &md5);
-                                               md5_hash(c->hostname, strlen(c->hostname), &md5);
+                                               if (dn_expand(ctxt.iface->search,
+                                                               ctxt.iface->search + ctxt.iface->search_len,
+                                                               ctxt.iface->search, b, sizeof(b)) > 0)
+                                                       fprintf(ctxt.fp, "\t%s.%s", c->hostname, b);
+
+                                               fprintf(ctxt.fp, "\t%s\n", c->hostname);
+                                               md5_hash(ipbuf, strlen(ipbuf), &ctxt.md5);
+                                               md5_hash(c->hostname, strlen(c->hostname), &ctxt.md5);
                                        }
 
-                                       l += snprintf(leasebuf + l, sizeof(leasebuf) - l, "%s/32 ", ipbuf);
-                                       leasebuf[l - 1] = '\n';
-                                       fwrite(leasebuf, 1, l, fp);
+                                       ctxt.buf_idx += snprintf(ctxt.buf + ctxt.buf_idx,
+                                                                       ctxt.buf_len - ctxt.buf_idx,
+                                                                       "%s/32 ", ipbuf);
+                                       ctxt.buf[ctxt.buf_idx - 1] = '\n';
+                                       fwrite(ctxt.buf, 1, ctxt.buf_idx, ctxt.fp);
                                }
                        }
                }
 
-               fclose(fp);
+               fclose(ctxt.fp);
        }
 
        uint8_t newmd5[16];
-       md5_end(newmd5, &md5);
+       md5_end(newmd5, &ctxt.md5);
 
        if (config.dhcp_cb && memcmp(newmd5, statemd5, sizeof(newmd5))) {
                memcpy(statemd5, newmd5, sizeof(statemd5));
@@ -393,8 +444,9 @@ static void apply_lease(struct interface *iface, struct dhcpv6_assignment *a, bo
        size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
 
        for (size_t i = 0; i < addrlen; ++i) {
-               struct in6_addr prefix = addrs[i].addr;
+               struct in6_addr prefix = addrs[i].addr.in6;
                prefix.s6_addr32[1] |= htonl(a->assigned);
+               prefix.s6_addr32[2] = prefix.s6_addr32[3] = 0;
                odhcpd_setup_route(&prefix, (a->managed_size) ? addrs[i].prefix : a->length,
                                iface, &a->peer.sin6_addr, 1024, add);
        }
@@ -605,15 +657,17 @@ void dhcpv6_ia_preupdate(struct interface *iface)
                        &iface->ia_assignments, struct dhcpv6_assignment, head);
 
        list_for_each_entry(c, &iface->ia_assignments, head)
-               if (c != border && !iface->managed && (c->flags & OAF_BOUND))
+               if (c != border && iface->ra_managed == RA_MANAGED_NO_MFLAG
+                               && (c->flags & OAF_BOUND))
                        apply_lease(iface, c, false);
 }
 
-void dhcpv6_ia_postupdate(struct interface *iface, time_t now)
+void dhcpv6_ia_postupdate(struct interface *iface)
 {
        if (iface->dhcpv6 != RELAYD_SERVER)
                return;
 
+       time_t now = odhcpd_time();
        int minprefix = -1;
        for (size_t i = 0; i < iface->ia_addr_len; ++i) {
                if (iface->ia_addr[i].preferred > (uint32_t)now &&
@@ -728,7 +782,7 @@ static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
 
                        struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
                        size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
-                       size_t m = elect_addr(addrs, addrlen);
+                       size_t m = get_preferred_addr(addrs, addrlen);
 
                        for (size_t i = 0; i < addrlen; ++i) {
                                uint32_t prefix_pref = addrs[i].preferred;
@@ -750,9 +804,10 @@ static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
                                                .preferred = htonl(prefix_pref),
                                                .valid = htonl(prefix_valid),
                                                .prefix = (a->managed_size) ? addrs[i].prefix : a->length,
-                                               .addr = addrs[i].addr
+                                               .addr = addrs[i].addr.in6,
                                        };
                                        p.addr.s6_addr32[1] |= htonl(a->assigned);
+                                       p.addr.s6_addr32[2] = p.addr.s6_addr32[3] = 0;
 
                                        size_t entrlen = sizeof(p) - 4;
 
@@ -767,7 +822,7 @@ static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
                                        struct dhcpv6_ia_addr n = {
                                                .type = htons(DHCPV6_OPT_IA_ADDR),
                                                .len = htons(sizeof(n) - 4),
-                                               .addr = addrs[i].addr,
+                                               .addr = addrs[i].addr.in6,
                                                .preferred = htonl(prefix_pref),
                                                .valid = htonl(prefix_valid)
                                        };
@@ -826,9 +881,10 @@ static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
                                                if (!valid_addr(&addrs[i], now))
                                                        continue;
 
-                                               struct in6_addr addr = addrs[i].addr;
+                                               struct in6_addr addr = addrs[i].addr.in6;
                                                if (ia->type == htons(DHCPV6_OPT_IA_PD)) {
                                                        addr.s6_addr32[1] |= htonl(a->assigned);
+                                                       addr.s6_addr32[2] = addr.s6_addr32[3] = 0;
 
                                                        if (!memcmp(&p->addr, &addr, sizeof(addr)) &&
                                                                        p->prefix == ((a->managed) ? addrs[i].prefix : a->length))
@@ -883,6 +939,23 @@ static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
        return datalen;
 }
 
+struct log_ctxt {
+       char *buf;
+       int buf_len;
+       int buf_idx;
+};
+
+static void dhcpv6_log_ia_addr(struct in6_addr *addr, int prefix, _unused uint32_t pref,
+                               _unused uint32_t valid, void *arg)
+{
+       struct log_ctxt *ctxt = (struct log_ctxt *)arg;
+       char addrbuf[INET6_ADDRSTRLEN];
+
+       inet_ntop(AF_INET6, addr, addrbuf, sizeof(addrbuf));
+       ctxt->buf_idx += snprintf(ctxt->buf + ctxt->buf_idx, ctxt->buf_len - ctxt->buf_idx,
+                                       "%s/%d ", addrbuf, prefix);
+}
+
 static void dhcpv6_log(uint8_t msgtype, struct interface *iface, time_t now,
                const char *duidbuf, bool is_pd, struct dhcpv6_assignment *a, int code)
 {
@@ -937,35 +1010,11 @@ static void dhcpv6_log(uint8_t msgtype, struct interface *iface, time_t now,
        char leasebuf[256] = "";
 
        if (a) {
-               struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->ia_addr;
-               size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->ia_addr_len;
-               size_t lbsize = 0;
-               size_t m = elect_addr(addrs, addrlen);
-               char addrbuf[INET6_ADDRSTRLEN];
-
-               for (size_t i = 0; i < addrlen; ++i) {
-                       if (!valid_addr(&addrs[i], now))
-                               continue;
+               struct log_ctxt ctxt = {.buf = leasebuf,
+                                       .buf_len = sizeof(leasebuf),
+                                       .buf_idx = 0 };
 
-                       struct in6_addr addr = addrs[i].addr;
-                       int prefix = a->managed ? addrs[i].prefix : a->length;
-                       if (prefix == 128) {
-                               if (!ADDR_ENTRY_VALID_IA_ADDR(iface, i, m, addrs) ||
-                                               a->assigned == 0)
-                                       continue;
-
-                               addr.s6_addr32[3] = htonl(a->assigned);
-                       }
-                       else {
-                               if (!valid_prefix_length(a, addrs[i].prefix))
-                                       continue;
-
-                               addr.s6_addr32[1] |= htonl(a->assigned);
-                       }
-
-                       inet_ntop(AF_INET6, &addr, addrbuf, sizeof(addrbuf));
-                       lbsize += snprintf(leasebuf + lbsize, sizeof(leasebuf) - lbsize, "%s/%d ", addrbuf, prefix);
-               }
+               dhcpv6_enum_ia_addrs(iface, a, now, dhcpv6_log_ia_addr, &ctxt);
        }
 
        syslog(LOG_WARNING, "DHCPV6 %s %s from %s on %s: %s %s", type, (is_pd) ? "IA_PD" : "IA_NA",
@@ -1086,7 +1135,9 @@ ssize_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
                if (a && a->managed_size < 0)
                        return -1;
 
-               if (hdr->msg_type == DHCPV6_MSG_SOLICIT || hdr->msg_type == DHCPV6_MSG_REQUEST) {
+               if (hdr->msg_type == DHCPV6_MSG_SOLICIT ||
+                               hdr->msg_type == DHCPV6_MSG_REQUEST ||
+                               (hdr->msg_type == DHCPV6_MSG_REBIND && !a)) {
                        bool assigned = !!a;
 
                        if (!a && !iface->no_dynamic_dhcp) {
@@ -1122,7 +1173,7 @@ ssize_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
                        if (!assigned || iface->ia_addr_len == 0)
                                /* Set error status */
                                status = (is_pd) ? DHCPV6_STATUS_NOPREFIXAVAIL : DHCPV6_STATUS_NOADDRSAVAIL;
-                       else if (assigned && !first) {
+                       else if (assigned && !first && hdr->msg_type != DHCPV6_MSG_REBIND) {
                                size_t handshake_len = 4;
                                buf[0] = 0;
                                buf[1] = DHCPV6_OPT_RECONF_ACCEPT;
@@ -1150,7 +1201,8 @@ ssize_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
                                first = a;
                        }
 
-                       ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
+                       ia_response_len = append_reply(buf, buflen, status, ia, a, iface,
+                                                       hdr->msg_type == DHCPV6_MSG_REBIND ? false : true);
 
                        /* Was only a solicitation: mark binding for removal */
                        if (assigned && hdr->msg_type == DHCPV6_MSG_SOLICIT) {
@@ -1158,7 +1210,9 @@ ssize_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
 
                                if (!(a->flags & OAF_STATIC))
                                        a->valid_until = now;
-                       } else if (assigned && hdr->msg_type == DHCPV6_MSG_REQUEST) {
+                       } else if (assigned &&
+                                       (hdr->msg_type == DHCPV6_MSG_REQUEST ||
+                                        hdr->msg_type == DHCPV6_MSG_REBIND)) {
                                if (hostname_len > 0) {
                                        a->hostname = realloc(a->hostname, hostname_len + 1);
                                        if (a->hostname) {