+ return NULL;
+}
+
+int sd_rtnl_message_get_type(sd_rtnl_message *m, uint16_t *type) {
+ assert_return(m, -EINVAL);
+ assert_return(type, -EINVAL);
+
+ *type = m->hdr->nlmsg_type;
+
+ return 0;
+}
+
+int sd_rtnl_message_is_broadcast(sd_rtnl_message *m) {
+ assert_return(m, -EINVAL);
+
+ return !m->hdr->nlmsg_pid;
+}
+
+int sd_rtnl_message_link_get_ifindex(sd_rtnl_message *m, int *ifindex) {
+ struct ifinfomsg *ifi;
+
+ assert_return(m, -EINVAL);
+ assert_return(m->hdr, -EINVAL);
+ assert_return(rtnl_message_type_is_link(m->hdr->nlmsg_type), -EINVAL);
+ assert_return(ifindex, -EINVAL);
+
+ ifi = NLMSG_DATA(m->hdr);
+
+ *ifindex = ifi->ifi_index;
+
+ return 0;
+}
+
+int sd_rtnl_message_link_get_flags(sd_rtnl_message *m, unsigned *flags) {
+ struct ifinfomsg *ifi;
+
+ assert_return(m, -EINVAL);
+ assert_return(m->hdr, -EINVAL);
+ assert_return(rtnl_message_type_is_link(m->hdr->nlmsg_type), -EINVAL);
+ assert_return(flags, -EINVAL);
+
+ ifi = NLMSG_DATA(m->hdr);
+
+ *flags = ifi->ifi_flags;
+
+ return 0;
+}
+
+int sd_rtnl_message_link_get_type(sd_rtnl_message *m, unsigned *type) {
+ struct ifinfomsg *ifi;
+
+ assert_return(m, -EINVAL);
+ assert_return(m->hdr, -EINVAL);
+ assert_return(rtnl_message_type_is_link(m->hdr->nlmsg_type), -EINVAL);
+ assert_return(type, -EINVAL);
+
+ ifi = NLMSG_DATA(m->hdr);
+
+ *type = ifi->ifi_type;
+
+ return 0;
+}
+
+/* If successful the updated message will be correctly aligned, if
+ unsuccessful the old message is untouched. */
+static int add_rtattr(sd_rtnl_message *m, unsigned short type, const void *data, size_t data_length) {
+ uint32_t rta_length;
+ size_t message_length, padding_length;
+ struct nlmsghdr *new_hdr;
+ struct rtattr *rta;
+ char *padding;
+ unsigned i;
+ int offset;
+
+ assert(m);
+ assert(m->hdr);
+ assert(!m->sealed);
+ assert(NLMSG_ALIGN(m->hdr->nlmsg_len) == m->hdr->nlmsg_len);
+ assert(!data || data_length);
+
+ /* get offset of the new attribute */
+ offset = m->hdr->nlmsg_len;
+
+ /* get the size of the new rta attribute (with padding at the end) */
+ rta_length = RTA_LENGTH(data_length);
+
+ /* get the new message size (with padding at the end) */
+ message_length = offset + RTA_ALIGN(rta_length);
+
+ /* realloc to fit the new attribute */
+ new_hdr = realloc(m->hdr, message_length);
+ if (!new_hdr)
+ return -ENOMEM;
+ m->hdr = new_hdr;
+
+ /* get pointer to the attribute we are about to add */
+ rta = (struct rtattr *) ((uint8_t *) m->hdr + offset);
+
+ /* if we are inside containers, extend them */
+ for (i = 0; i < m->n_containers; i++)
+ GET_CONTAINER(m, i)->rta_len += message_length - offset;
+
+ /* fill in the attribute */
+ rta->rta_type = type;
+ rta->rta_len = rta_length;
+ if (data)
+ /* we don't deal with the case where the user lies about the type
+ * and gives us too little data (so don't do that)
+ */
+ padding = mempcpy(RTA_DATA(rta), data, data_length);
+ else {
+ /* if no data was passed, make sure we still initialize the padding
+ note that we can have data_length > 0 (used by some containers) */
+ padding = RTA_DATA(rta);
+ }
+
+ /* make sure also the padding at the end of the message is initialized */
+ padding_length = (uint8_t*)m->hdr + message_length - (uint8_t*)padding;
+ memzero(padding, padding_length);
+
+ /* update message size */
+ m->hdr->nlmsg_len = message_length;
+
+ return offset;
+}
+
+static int message_attribute_has_type(sd_rtnl_message *m, uint16_t attribute_type, uint16_t data_type) {
+ const NLType *type;
+ int r;
+
+ r = type_system_get_type(m->container_type_system[m->n_containers], &type, attribute_type);
+ if (r < 0)
+ return r;
+
+ if (type->type != data_type)
+ return -EINVAL;
+
+ return type->size;
+}
+
+int sd_rtnl_message_append_string(sd_rtnl_message *m, unsigned short type, const char *data) {
+ size_t length, size;
+ int r;
+
+ assert_return(m, -EINVAL);
+ assert_return(!m->sealed, -EPERM);
+ assert_return(data, -EINVAL);
+
+ r = message_attribute_has_type(m, type, NLA_STRING);
+ if (r < 0)
+ return r;
+ else
+ size = (size_t)r;
+
+ if (size) {
+ length = strnlen(data, size+1);
+ if (length > size)
+ return -EINVAL;
+ } else
+ length = strlen(data);
+
+ r = add_rtattr(m, type, data, length + 1);
+ if (r < 0)
+ return r;
+
+ return 0;
+}
+
+int sd_rtnl_message_append_u8(sd_rtnl_message *m, unsigned short type, uint8_t data) {
+ int r;
+
+ assert_return(m, -EINVAL);
+ assert_return(!m->sealed, -EPERM);
+
+ r = message_attribute_has_type(m, type, NLA_U8);
+ if (r < 0)
+ return r;
+
+ r = add_rtattr(m, type, &data, sizeof(uint8_t));
+ if (r < 0)
+ return r;
+
+ return 0;
+}
+
+
+int sd_rtnl_message_append_u16(sd_rtnl_message *m, unsigned short type, uint16_t data) {
+ int r;
+
+ assert_return(m, -EINVAL);
+ assert_return(!m->sealed, -EPERM);
+
+ r = message_attribute_has_type(m, type, NLA_U16);
+ if (r < 0)
+ return r;
+
+ r = add_rtattr(m, type, &data, sizeof(uint16_t));
+ if (r < 0)
+ return r;
+
+ return 0;
+}
+
+int sd_rtnl_message_append_u32(sd_rtnl_message *m, unsigned short type, uint32_t data) {
+ int r;
+
+ assert_return(m, -EINVAL);
+ assert_return(!m->sealed, -EPERM);
+
+ r = message_attribute_has_type(m, type, NLA_U32);
+ if (r < 0)
+ return r;
+
+ r = add_rtattr(m, type, &data, sizeof(uint32_t));
+ if (r < 0)
+ return r;
+
+ return 0;
+}
+
+int sd_rtnl_message_append_in_addr(sd_rtnl_message *m, unsigned short type, const struct in_addr *data) {
+ int r;
+
+ assert_return(m, -EINVAL);
+ assert_return(!m->sealed, -EPERM);
+ assert_return(data, -EINVAL);
+
+ r = message_attribute_has_type(m, type, NLA_IN_ADDR);
+ if (r < 0)
+ return r;
+
+ r = add_rtattr(m, type, data, sizeof(struct in_addr));
+ if (r < 0)
+ return r;
+
+ return 0;
+}
+
+int sd_rtnl_message_append_in6_addr(sd_rtnl_message *m, unsigned short type, const struct in6_addr *data) {
+ int r;
+
+ assert_return(m, -EINVAL);
+ assert_return(!m->sealed, -EPERM);
+ assert_return(data, -EINVAL);
+
+ r = message_attribute_has_type(m, type, NLA_IN_ADDR);
+ if (r < 0)
+ return r;
+
+ r = add_rtattr(m, type, data, sizeof(struct in6_addr));
+ if (r < 0)
+ return r;
+
+ return 0;
+}
+
+int sd_rtnl_message_append_ether_addr(sd_rtnl_message *m, unsigned short type, const struct ether_addr *data) {
+ int r;
+
+ assert_return(m, -EINVAL);
+ assert_return(!m->sealed, -EPERM);
+ assert_return(data, -EINVAL);
+
+ r = message_attribute_has_type(m, type, NLA_ETHER_ADDR);
+ if (r < 0)
+ return r;
+
+ r = add_rtattr(m, type, data, ETH_ALEN);
+ if (r < 0)
+ return r;
+
+ return 0;
+}
+
+int sd_rtnl_message_append_cache_info(sd_rtnl_message *m, unsigned short type, const struct ifa_cacheinfo *info) {
+ int r;
+
+ assert_return(m, -EINVAL);
+ assert_return(!m->sealed, -EPERM);
+ assert_return(info, -EINVAL);
+
+ r = message_attribute_has_type(m, type, NLA_CACHE_INFO);
+ if (r < 0)
+ return r;
+
+ r = add_rtattr(m, type, info, sizeof(struct ifa_cacheinfo));
+ if (r < 0)
+ return r;
+
+ return 0;
+}
+
+int sd_rtnl_message_open_container(sd_rtnl_message *m, unsigned short type) {
+ size_t size;
+ int r;
+
+ assert_return(m, -EINVAL);
+ assert_return(!m->sealed, -EPERM);
+ assert_return(m->n_containers < RTNL_CONTAINER_DEPTH, -ERANGE);
+
+ r = message_attribute_has_type(m, type, NLA_NESTED);
+ if (r < 0)
+ return r;
+ else
+ size = (size_t)r;
+
+ r = type_system_get_type_system(m->container_type_system[m->n_containers],
+ &m->container_type_system[m->n_containers + 1],
+ type);
+ if (r < 0)
+ return r;