dhcpv6-ia: rework append_reply()
authorHans Dedecker <dedeckeh@gmail.com>
Tue, 29 Jan 2019 14:38:36 +0000 (15:38 +0100)
committerHans Dedecker <dedeckeh@gmail.com>
Thu, 31 Jan 2019 14:50:51 +0000 (15:50 +0100)
Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>
src/dhcpv6-ia.c

index 83de0a29f5faf6f5a0c3a554ab3cc99b4a049acd..8ac0a9efa5d1bc4841014af63e9cbe2bb12f6b43 100644 (file)
@@ -824,197 +824,215 @@ static void valid_until_cb(struct uloop_timeout *event)
        uloop_timeout_set(event, 1000);
 }
 
-static size_t append_reply(uint8_t *buf, size_t buflen, uint16_t status,
+static size_t build_ia(uint8_t *buf, size_t buflen, uint16_t status,
                const struct dhcpv6_ia_hdr *ia, struct dhcpv6_assignment *a,
                struct interface *iface, bool request)
 {
-       if (buflen < sizeof(*ia) + sizeof(struct dhcpv6_ia_prefix))
-               return 0;
-
-       struct dhcpv6_ia_hdr out = {ia->type, 0, ia->iaid, 0, 0};
-       size_t datalen = sizeof(out);
+       struct dhcpv6_ia_hdr o_ia = {
+               .type = ia->type,
+               .len = 0,
+               .iaid = ia->iaid,
+               .t1 = 0,
+               .t2 = 0,
+       };
+       size_t ia_len = sizeof(o_ia);
        time_t now = odhcpd_time();
 
+       if (buflen < ia_len)
+               return 0;
+
        if (status) {
                struct __attribute__((packed)) {
                        uint16_t type;
                        uint16_t len;
-                       uint16_t value;
-               } stat = {htons(DHCPV6_OPT_STATUS), htons(sizeof(stat) - 4),
-                               htons(status)};
-
-               memcpy(buf + datalen, &stat, sizeof(stat));
-               datalen += sizeof(stat);
-       } else {
-               if (a) {
-                       uint32_t leasetime;
-                       if (a->leasetime)
-                               leasetime = a->leasetime;
-                       else
-                               leasetime = iface->dhcpv4_leasetime;
+                       uint16_t val;
+               } o_status = {
+                       .type = htons(DHCPV6_OPT_STATUS),
+                       .len = htons(sizeof(o_status) - 4),
+                       .val = htons(status),
+               };
 
-                       uint32_t pref = leasetime;
-                       uint32_t valid = leasetime;
+               memcpy(buf + ia_len, &o_status, sizeof(o_status));
+               ia_len += sizeof(o_status);
 
-                       struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->addr6;
-                       size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->addr6_len;
-                       size_t m = get_preferred_addr(addrs, addrlen);
+               o_ia.len = htons(ia_len - 4);
+               memcpy(buf, &o_ia, sizeof(o_ia));
 
-                       for (size_t i = 0; i < addrlen; ++i) {
-                               uint32_t prefix_pref = addrs[i].preferred;
-                               uint32_t prefix_valid = addrs[i].valid;
+               return ia_len;
+       }
 
-                               if (!valid_addr(&addrs[i], now))
-                                       continue;
+       if (a) {
+               uint32_t leasetime;
 
-                               if (prefix_pref != UINT32_MAX)
-                                       prefix_pref -= now;
+               if (a->leasetime)
+                       leasetime = a->leasetime;
+               else
+                       leasetime = iface->dhcpv4_leasetime;
 
-                               if (prefix_valid != UINT32_MAX)
-                                       prefix_valid -= now;
+               uint32_t pref = leasetime;
+               uint32_t valid = leasetime;
 
-                               if (a->length < 128) {
-                                       struct dhcpv6_ia_prefix p = {
-                                               .type = htons(DHCPV6_OPT_IA_PREFIX),
-                                               .len = htons(sizeof(p) - 4),
-                                               .preferred = htonl(prefix_pref),
-                                               .valid = htonl(prefix_valid),
-                                               .prefix = (a->managed_size) ? addrs[i].prefix : a->length,
-                                               .addr = addrs[i].addr.in6,
-                                       };
-                                       p.addr.s6_addr32[1] |= htonl(a->assigned);
-                                       p.addr.s6_addr32[2] = p.addr.s6_addr32[3] = 0;
+               struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->addr6;
+               size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->addr6_len;
+               size_t m = get_preferred_addr(addrs, addrlen);
 
-                                       size_t entrlen = sizeof(p) - 4;
+               for (size_t i = 0; i < addrlen; ++i) {
+                       uint32_t prefix_pref = addrs[i].preferred;
+                       uint32_t prefix_valid = addrs[i].valid;
 
-                                       if (datalen + entrlen + 4 > buflen ||
-                                                       (a->assigned == 0 && a->managed_size == 0) ||
-                                                       !valid_prefix_length(a, addrs[i].prefix))
-                                               continue;
+                       if (!valid_addr(&addrs[i], now))
+                               continue;
 
-                                       memcpy(buf + datalen, &p, sizeof(p));
-                                       datalen += entrlen + 4;
-                               } else {
-                                       struct dhcpv6_ia_addr n = {
-                                               .type = htons(DHCPV6_OPT_IA_ADDR),
-                                               .len = htons(sizeof(n) - 4),
-                                               .addr = addrs[i].addr.in6,
-                                               .preferred = htonl(prefix_pref),
-                                               .valid = htonl(prefix_valid)
-                                       };
-                                       n.addr.s6_addr32[3] = htonl(a->assigned);
-                                       size_t entrlen = sizeof(n) - 4;
+                       if (prefix_pref != UINT32_MAX)
+                               prefix_pref -= now;
 
-                                       if (!ADDR_ENTRY_VALID_IA_ADDR(iface, i, m, addrs) ||
-                                                       a->assigned == 0 ||
-                                                       datalen + entrlen + 4 > buflen)
-                                               continue;
+                       if (prefix_valid != UINT32_MAX)
+                               prefix_valid -= now;
 
-                                       memcpy(buf + datalen, &n, sizeof(n));
-                                       datalen += entrlen + 4;
-                               }
+                       if (a->length < 128) {
+                               struct dhcpv6_ia_prefix o_ia_p = {
+                                       .type = htons(DHCPV6_OPT_IA_PREFIX),
+                                       .len = htons(sizeof(o_ia_p) - 4),
+                                       .preferred = htonl(prefix_pref),
+                                       .valid = htonl(prefix_valid),
+                                       .prefix = (a->managed_size) ? addrs[i].prefix : a->length,
+                                       .addr = addrs[i].addr.in6,
+                               };
 
-                               /* Calculate T1 / T2 based on non-deprecated addresses */
-                               if (prefix_pref > 0) {
-                                       if (prefix_pref < pref)
-                                               pref = prefix_pref;
+                               o_ia_p.addr.s6_addr32[1] |= htonl(a->assigned);
+                               o_ia_p.addr.s6_addr32[2] = o_ia_p.addr.s6_addr32[3] = 0;
 
-                                       if (prefix_valid < valid)
-                                               valid = prefix_valid;
-                               }
-                       }
+                               if ((a->assigned == 0 && a->managed_size == 0) ||
+                                               !valid_prefix_length(a, addrs[i].prefix))
+                                       continue;
 
-                       if (!INFINITE_VALID(a->valid_until))
-                               /* UINT32_MAX is considered as infinite leasetime */
-                               a->valid_until = (valid == UINT32_MAX) ? 0 : valid + now;
+                               if (buflen < ia_len + sizeof(o_ia_p))
+                                       return 0;
 
-                       out.t1 = htonl((pref == UINT32_MAX) ? pref : pref * 5 / 10);
-                       out.t2 = htonl((pref == UINT32_MAX) ? pref : pref * 8 / 10);
+                               memcpy(buf + ia_len, &o_ia_p, sizeof(o_ia_p));
+                               ia_len += sizeof(o_ia_p);
+                       } else {
+                               struct dhcpv6_ia_addr o_ia_a = {
+                                       .type = htons(DHCPV6_OPT_IA_ADDR),
+                                       .len = htons(sizeof(o_ia_a) - 4),
+                                       .addr = addrs[i].addr.in6,
+                                       .preferred = htonl(prefix_pref),
+                                       .valid = htonl(prefix_valid)
+                               };
+
+                               o_ia_a.addr.s6_addr32[3] = htonl(a->assigned);
+
+                               if (!ADDR_ENTRY_VALID_IA_ADDR(iface, i, m, addrs) ||
+                                               a->assigned == 0)
+                                       continue;
+
+                               if (buflen < ia_len + sizeof(o_ia_a))
+                                       return 0;
+
+                               memcpy(buf + ia_len, &o_ia_a, sizeof(o_ia_a));
+                               ia_len += sizeof(o_ia_a);
+                       }
 
-                       if (!out.t1)
-                               out.t1 = htonl(1);
+                       /* Calculate T1 / T2 based on non-deprecated addresses */
+                       if (prefix_pref > 0) {
+                               if (prefix_pref < pref)
+                                       pref = prefix_pref;
 
-                       if (!out.t2)
-                               out.t2 = htonl(1);
+                               if (prefix_valid < valid)
+                                       valid = prefix_valid;
+                       }
                }
 
-               if (!request) {
-                       uint8_t *odata, *end = ((uint8_t*)ia) + htons(ia->len) + 4;
-                       uint16_t otype, olen;
+               if (!INFINITE_VALID(a->valid_until))
+                       /* UINT32_MAX is considered as infinite leasetime */
+                       a->valid_until = (valid == UINT32_MAX) ? 0 : valid + now;
 
-                       dhcpv6_for_each_option((uint8_t*)&ia[1], end, otype, olen, odata) {
-                               struct dhcpv6_ia_prefix *p = (struct dhcpv6_ia_prefix*)&odata[-4];
-                               struct dhcpv6_ia_addr *n = (struct dhcpv6_ia_addr*)&odata[-4];
-                               bool found = false;
+               o_ia.t1 = htonl((pref == UINT32_MAX) ? pref : pref * 5 / 10);
+               o_ia.t2 = htonl((pref == UINT32_MAX) ? pref : pref * 8 / 10);
 
-                               if ((otype != DHCPV6_OPT_IA_PREFIX || olen < sizeof(*p) - 4) &&
-                                               (otype != DHCPV6_OPT_IA_ADDR || olen < sizeof(*n) - 4))
-                                       continue;
+               if (!o_ia.t1)
+                       o_ia.t1 = htonl(1);
 
-                               if (a) {
-                                       struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->addr6;
-                                       size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->addr6_len;
-
-                                       for (size_t i = 0; i < addrlen; ++i) {
-                                               if (!valid_addr(&addrs[i], now))
-                                                       continue;
-
-                                               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))
-                                                               found = true;
-                                               } else {
-                                                       addr.s6_addr32[3] = htonl(a->assigned);
-
-                                                       if (!memcmp(&n->addr, &addr, sizeof(addr)))
-                                                               found = true;
-                                               }
-                                       }
-                               }
+               if (!o_ia.t2)
+                       o_ia.t2 = htonl(1);
+       }
+
+       if (!request) {
+               uint8_t *odata, *end = ((uint8_t*)ia) + htons(ia->len) + 4;
+               uint16_t otype, olen;
+
+               dhcpv6_for_each_option((uint8_t*)&ia[1], end, otype, olen, odata) {
+                       struct dhcpv6_ia_prefix *ia_p = (struct dhcpv6_ia_prefix *)&odata[-4];
+                       struct dhcpv6_ia_addr *ia_a = (struct dhcpv6_ia_addr *)&odata[-4];
+                       bool found = false;
+
+                       if ((otype != DHCPV6_OPT_IA_PREFIX || olen < sizeof(*ia_p) - 4) &&
+                                       (otype != DHCPV6_OPT_IA_ADDR || olen < sizeof(*ia_a) - 4))
+                               continue;
+
+                       if (a) {
+                               struct odhcpd_ipaddr *addrs = (a->managed) ? a->managed : iface->addr6;
+                               size_t addrlen = (a->managed) ? (size_t)a->managed_size : iface->addr6_len;
+
+                               for (size_t i = 0; i < addrlen; ++i) {
+                                       if (!valid_addr(&addrs[i], now))
+                                               continue;
+
+                                       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 (!found) {
-                                       if (otype == DHCPV6_OPT_IA_PREFIX) {
-                                               struct dhcpv6_ia_prefix inv = {
-                                                       .type = htons(DHCPV6_OPT_IA_PREFIX),
-                                                       .len = htons(sizeof(inv) - 4),
-                                                       .preferred = 0,
-                                                       .valid = 0,
-                                                       .prefix = p->prefix,
-                                                       .addr = p->addr
-                                               };
-
-                                               if (datalen + sizeof(inv) > buflen)
-                                                       continue;
-
-                                               memcpy(buf + datalen, &inv, sizeof(inv));
-                                               datalen += sizeof(inv);
+                                               if (!memcmp(&ia_p->addr, &addr, sizeof(addr)) &&
+                                                               ia_p->prefix == ((a->managed) ? addrs[i].prefix : a->length))
+                                                       found = true;
                                        } else {
-                                               struct dhcpv6_ia_addr inv = {
-                                                       .type = htons(DHCPV6_OPT_IA_ADDR),
-                                                       .len = htons(sizeof(inv) - 4),
-                                                       .addr = n->addr,
-                                                       .preferred = 0,
-                                                       .valid = 0
-                                               };
-
-                                               if (datalen + sizeof(inv) > buflen)
-                                                       continue;
-
-                                               memcpy(buf + datalen, &inv, sizeof(inv));
-                                               datalen += sizeof(inv);
+                                               addr.s6_addr32[3] = htonl(a->assigned);
+
+                                               if (!memcmp(&ia_a->addr, &addr, sizeof(addr)))
+                                                       found = true;
                                        }
                                }
                        }
+
+                       if (!found) {
+                               if (otype == DHCPV6_OPT_IA_PREFIX) {
+                                       struct dhcpv6_ia_prefix o_ia_p = {
+                                               .type = htons(DHCPV6_OPT_IA_PREFIX),
+                                               .len = htons(sizeof(o_ia_p) - 4),
+                                               .preferred = 0,
+                                               .valid = 0,
+                                               .prefix = ia_p->prefix,
+                                               .addr = ia_p->addr,
+                                       };
+
+                                       if (buflen < ia_len + sizeof(o_ia_p))
+                                               return 0;
+
+                                       memcpy(buf + ia_len, &o_ia_p, sizeof(o_ia_p));
+                                       ia_len += sizeof(o_ia_p);
+                               } else {
+                                       struct dhcpv6_ia_addr o_ia_a = {
+                                               .type = htons(DHCPV6_OPT_IA_ADDR),
+                                               .len = htons(sizeof(o_ia_a) - 4),
+                                               .addr = ia_a->addr,
+                                               .preferred = 0,
+                                               .valid = 0,
+                                       };
+
+                                       if (buflen < ia_len + sizeof(o_ia_a))
+                                               continue;
+
+                                       memcpy(buf + ia_len, &o_ia_a, sizeof(o_ia_a));
+                                       ia_len += sizeof(o_ia_a);
+                               }
+                       }
                }
        }
 
-       out.len = htons(datalen - 4);
-       memcpy(buf, &out, sizeof(out));
-       return datalen;
+       o_ia.len = htons(ia_len - 4);
+       memcpy(buf, &o_ia, sizeof(o_ia));
+       return ia_len;
 }
 
 struct log_ctxt {
@@ -1330,7 +1348,7 @@ 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,
+                       ia_response_len = build_ia(buf, buflen, status, ia, a, iface,
                                                        hdr->msg_type == DHCPV6_MSG_REBIND ? false : true);
 
                        /* Was only a solicitation: mark binding for removal */
@@ -1371,10 +1389,10 @@ ssize_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
                                hdr->msg_type == DHCPV6_MSG_DECLINE) {
                        if (!a && hdr->msg_type != DHCPV6_MSG_REBIND) {
                                status = DHCPV6_STATUS_NOBINDING;
-                               ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
+                               ia_response_len = build_ia(buf, buflen, status, ia, a, iface, false);
                        } else if (hdr->msg_type == DHCPV6_MSG_RENEW ||
                                        hdr->msg_type == DHCPV6_MSG_REBIND) {
-                               ia_response_len = append_reply(buf, buflen, status, ia, a, iface, false);
+                               ia_response_len = build_ia(buf, buflen, status, ia, a, iface, false);
                                if (a) {
                                        a->flags |= OAF_BOUND;
                                        apply_lease(iface, a, true);
@@ -1398,7 +1416,7 @@ ssize_t dhcpv6_handle_ia(uint8_t *buf, size_t buflen, struct interface *iface,
                } else if (hdr->msg_type == DHCPV6_MSG_CONFIRM && ia_addr_present) {
                        /* Send NOTONLINK for CONFIRM with addr present so that clients restart connection */
                        status = DHCPV6_STATUS_NOTONLINK;
-                       ia_response_len = append_reply(buf, buflen, status, ia, a, iface, true);
+                       ia_response_len = build_ia(buf, buflen, status, ia, a, iface, true);
                        notonlink = true;
                }