Extended prefix_filter to work in relay mode for RA and NDP

Author: lqf96

src/config.c

@@ -1707,8 +1707,8 @@ int config_parse_interface(void *data, size_t len, const char *name, bool overwr
 
 	if ((c = tb[IFACE_ATTR_PREFIX_FILTER]))
 		odhcpd_parse_addr6_prefix(blobmsg_get_string(c),
-					  &iface->pio_filter_addr,
-					  &iface->pio_filter_length);
+					  &iface->prefix_filter_addr,
+					  &iface->prefix_filter_length);
 
 	if (overwrite && (c = tb[IFACE_ATTR_NTP])) {
 		struct blob_attr *cur;

src/dhcpv6-ia.c

@@ -295,7 +295,7 @@ static void __apply_lease(struct dhcpv6_lease *a,
 	for (ssize_t i = 0; i < addr_len; ++i) {
 		struct in6_addr prefix;
 
-		if (ADDR_MATCH_PIO_FILTER(&addrs[i], a->iface))
+		if (ADDR_MATCH_PREFIX_FILTER(&addrs[i], a->iface))
 			continue;
 
 		prefix = addrs[i].addr.in6;
@@ -324,7 +324,7 @@ static void set_border_assignment_size(struct interface *iface, struct dhcpv6_le
 	for (size_t i = 0; i < iface->addr6_len; ++i) {
 		struct odhcpd_ipaddr *addr = &iface->addr6[i];
 
-		if (ADDR_MATCH_PIO_FILTER(addr, iface))
+		if (ADDR_MATCH_PREFIX_FILTER(addr, iface))
 			continue;
 
 		if (addr->preferred_lt > (uint32_t)now &&
@@ -634,7 +634,7 @@ static size_t build_ia(uint8_t *buf, size_t buflen, uint16_t status,
 				continue;
 
 			/* Filter Out Prefixes */
-			if (ADDR_MATCH_PIO_FILTER(&addrs[i], iface)) {
+			if (ADDR_MATCH_PREFIX_FILTER(&addrs[i], iface)) {
 				char addrbuf[INET6_ADDRSTRLEN];
 				info("Address %s filtered out on %s",
 				     inet_ntop(AF_INET6, &addrs[i].addr.in6, addrbuf, sizeof(addrbuf)),
@@ -761,7 +761,7 @@ static size_t build_ia(uint8_t *buf, size_t buflen, uint16_t status,
 					if (!valid_prefix_length(a, addrs[i].prefix_len))
 						continue;
 
-					if (ADDR_MATCH_PIO_FILTER(&addrs[i], iface))
+					if (ADDR_MATCH_PREFIX_FILTER(&addrs[i], iface))
 						continue;
 
 					if (ia->type == htons(DHCPV6_OPT_IA_PD)) {
@@ -934,7 +934,7 @@ static bool dhcpv6_ia_on_link(const struct dhcpv6_ia_hdr *ia, struct dhcpv6_leas
 			if (!valid_addr(&addrs[i], now))
 				continue;
 
-			if (ADDR_MATCH_PIO_FILTER(&addrs[i], iface))
+			if (ADDR_MATCH_PREFIX_FILTER(&addrs[i], iface))
 				continue;
 
 			if (ia->type == htons(DHCPV6_OPT_IA_PD)) {

src/ndp.c

@@ -278,12 +278,18 @@ static void ndp_netevent_cb(unsigned long event, struct netevent_handler_info *i
 		netlink_dump_neigh_table(false);
 		_o_fallthrough;
 	case NETEV_ADDR6_ADD:
+		if (IN6_MATCH_PREFIX_FILTER(info->addr.in6, iface))
+			break; /* Address filtered out */
+
 		setup_addr_for_relaying(&info->addr.in6, iface, add);
 		break;
 	case NETEV_NEIGH6_DEL:
 		add = false;
 		_o_fallthrough;
 	case NETEV_NEIGH6_ADD:
+		if (IN6_MATCH_PREFIX_FILTER(info->neigh.dst.in6, iface))
+			break; /* Address filtered out */
+
 		if (info->neigh.flags & NTF_PROXY) {
 			if (add) {
 				netlink_setup_proxy_neigh(&info->neigh.dst.in6, iface->ifindex, false);
@@ -380,13 +386,16 @@ static void handle_solicit(void *addr, void *data, size_t len,
 		return;
 
 	if (len < sizeof(*ip6) + sizeof(*req))
-		return; // Invalid total length
+		return; /* Invalid total length */
 
 	if (IN6_IS_ADDR_LINKLOCAL(&req->nd_ns_target) ||
 			IN6_IS_ADDR_LOOPBACK(&req->nd_ns_target) ||
 			IN6_IS_ADDR_MULTICAST(&req->nd_ns_target))
 		return; /* Invalid target */
 
+	if (IN6_MATCH_PREFIX_FILTER(req->nd_ns_target, iface))
+		return; /* Address filtered out */
+
 	inet_ntop(AF_INET6, &req->nd_ns_target, ipbuf, sizeof(ipbuf));
 	debug("Got a NS for %s on %s", ipbuf, iface->name);
 

src/odhcpd.c

@@ -680,7 +680,7 @@ void odhcpd_enum_addr6(struct interface *iface, struct dhcpv6_lease *lease,
 			continue;
 
 		/* Filter Out Prefixes */
-		if (ADDR_MATCH_PIO_FILTER(&addrs[i], iface)) {
+		if (ADDR_MATCH_PREFIX_FILTER(&addrs[i], iface)) {
 			char addrbuf[INET6_ADDRSTRLEN];
 			info("Address %s filtered out on %s",
 			     inet_ntop(AF_INET6, &addrs[i].addr.in6, addrbuf, sizeof(addrbuf)),
@@ -789,3 +789,52 @@ bool odhcpd_hostname_valid(const char *name)
 
 	return (label_sz && label_sz <= DNS_MAX_LABEL_LEN ? true : false);
 }
+
+void odhcpd_iov_builder_init(struct iov_builder *builder, uint8_t *data, struct iovec* iov_buf, size_t iov_capacity) {
+	builder->iov_count = 0;
+	builder->current_iov_base = data;
+	builder->current_iov_len = 0;
+	builder->include_iov = false;
+
+	if (iov_buf) {
+		builder->iov_buf = iov_buf;
+		builder->iov_capacity = iov_capacity;
+	}
+}
+
+int odhcpd_iov_builder_advance(struct iov_builder *builder, size_t chunk_len, bool include_chunk) {
+	if (include_chunk ^ builder->include_iov) {
+		if (builder->include_iov) {
+			int error = odhcpd_iov_builder_append(builder, builder->current_iov_base, builder->current_iov_len);
+			if (error)
+				return error;
+		}
+
+		builder->current_iov_base += builder->current_iov_len;
+		builder->current_iov_len = chunk_len;
+		builder->include_iov = include_chunk;
+	} else {
+		builder->current_iov_len += chunk_len;
+	}
+
+	return 0;
+}
+
+int odhcpd_iov_builder_append(struct iov_builder *builder, uint8_t *iov_base, size_t iov_len) {
+	if (iov_len == 0)
+		return 0;
+	if (builder->iov_count >= builder->iov_capacity)
+		return 1;
+
+	builder->iov_buf[builder->iov_count] = (struct iovec) {
+		.iov_base = iov_base,
+		.iov_len = iov_len
+	};
+	builder->iov_count++;
+
+	return 0;
+}
+
+int odhcpd_iov_builder_finalize(struct iov_builder *builder) {
+	return odhcpd_iov_builder_advance(builder, 0, false);
+}

src/odhcpd.h

@@ -82,10 +82,12 @@
 
 #define IN6_IS_ADDR_ULA(a) (((a)->s6_addr32[0] & htonl(0xfe000000)) == htonl(0xfc000000))
 
-#define ADDR_MATCH_PIO_FILTER(_addr, iface) (odhcpd_bmemcmp(&(_addr)->addr, \
-							    &(iface)->pio_filter_addr, \
-							    (iface)->pio_filter_length) != 0 || \
-					     (_addr)->prefix_len < (iface)->pio_filter_length)
+#define IN6_MATCH_PREFIX_FILTER(_addr, iface) (odhcpd_bmemcmp(&(_addr), \
+							&(iface)->prefix_filter_addr, \
+							(iface)->prefix_filter_length) != 0)
+
+#define ADDR_MATCH_PREFIX_FILTER(_addr, iface) (IN6_MATCH_PREFIX_FILTER((_addr)->addr, iface) || \
+							(_addr)->prefix_len < (iface)->prefix_filter_length)
 
 struct interface;
 struct nl_sock;
@@ -423,8 +425,8 @@ struct interface {
 	uint32_t pref64_prefix[3];
 	bool no_dynamic_dhcp;
 	bool have_link_local;
-	uint8_t pio_filter_length;
-	struct in6_addr pio_filter_addr;
+	uint8_t prefix_filter_length;
+	struct in6_addr prefix_filter_addr;
 	int default_router;
 	int route_preference;
 	uint32_t ra_maxinterval;
@@ -666,4 +668,18 @@ void reload_services(struct interface *iface);
 
 void odhcpd_reload(void);
 
+struct iov_builder {
+	struct iovec *iov_buf;
+	size_t iov_capacity;
+	size_t iov_count;
+	uint8_t *current_iov_base;
+	size_t current_iov_len;
+	bool include_iov;
+};
+
+void odhcpd_iov_builder_init(struct iov_builder *builder, uint8_t *data, struct iovec* iov_buf, size_t iov_capacity);
+int odhcpd_iov_builder_advance(struct iov_builder *builder, size_t chunk_len, bool include_chunk);
+int odhcpd_iov_builder_append(struct iov_builder *builder, uint8_t *iov_base, size_t iov_len);
+int odhcpd_iov_builder_finalize(struct iov_builder *builder);
+
 #endif /* _ODHCPD_H_ */