Handle IPv4 broadcast addresses

include/net/net_if.h

@@ -1428,7 +1428,18 @@ struct net_if_router *net_if_ipv4_router_add(struct net_if *iface,
  * @return True if address is part of local subnet, false otherwise.
  */
 bool net_if_ipv4_addr_mask_cmp(struct net_if *iface,
-			       struct in_addr *addr);
+			       const struct in_addr *addr);
+
+/**
+ * @brief Check if the given IPv4 address is a broadcast address.
+ *
+ * @param iface Interface to use. Must be a valid pointer to an interface.
+ * @param addr IPv4 address, this should be in network byte order
+ *
+ * @return True if address is a broadcast address, false otherwise.
+ */
+bool net_if_ipv4_is_addr_bcast(struct net_if *iface,
+			       const struct in_addr *addr);
 
 /**
  * @brief Get a network interface that should be used when sending
@@ -1474,7 +1485,7 @@ struct in_addr *net_if_ipv4_get_ll(struct net_if *iface,
  * @param netmask IPv4 netmask
  */
 static inline void net_if_ipv4_set_netmask(struct net_if *iface,
-					   struct in_addr *netmask)
+					   const struct in_addr *netmask)
 {
 	if (net_if_config_ipv4_get(iface, NULL) < 0) {
 		return;

include/net/net_ip.h

@@ -477,23 +477,6 @@ static inline bool net_is_ipv4_ll_addr(const struct in_addr *addr)
 	return (ntohl(UNALIGNED_GET(&addr->s_addr)) & 0xA9FE0000) == 0xA9FE0000;
 }
 
-extern struct net_if_addr *net_if_ipv4_addr_lookup(const struct in_addr *addr,
-						   struct net_if **iface);
-
-/**
- * @brief Check if the IPv4 address is assigned to any network interface
- * in the system.
- *
- * @param addr A valid pointer on an IPv4 address
- *
- * @return True if IPv4 address is found in one of the network interfaces,
- * False otherwise.
- */
-static inline bool net_is_my_ipv4_addr(const struct in_addr *addr)
-{
-	return net_if_ipv4_addr_lookup(addr, NULL) != NULL;
-}
-
 /**
  *  @def net_ipaddr_copy
  *  @brief Copy an IPv4 or IPv6 address
@@ -569,23 +552,68 @@ const struct in_addr *net_ipv4_broadcast_address(void);
 
 struct net_if;
 extern bool net_if_ipv4_addr_mask_cmp(struct net_if *iface,
-				      struct in_addr *addr);
+				      const struct in_addr *addr);
 
 /**
  * @brief Check if the given address belongs to same subnet that
  * has been configured for the interface.
  *
  * @param iface A valid pointer on an interface
- * @param addr pointer on an address
+ * @param addr IPv4 address
  *
  * @return True if address is in same subnet, false otherwise.
  */
 static inline bool net_ipv4_addr_mask_cmp(struct net_if *iface,
-					  struct in_addr *addr)
+					  const struct in_addr *addr)
 {
 	return net_if_ipv4_addr_mask_cmp(iface, addr);
 }
 
+extern bool net_if_ipv4_is_addr_bcast(struct net_if *iface,
+				      const struct in_addr *addr);
+
+/**
+ * @brief Check if the given IPv4 address is a broadcast address.
+ *
+ * @param iface Interface to use. Must be a valid pointer to an interface.
+ * @param addr IPv4 address
+ *
+ * @return True if address is a broadcast address, false otherwise.
+ */
+static inline bool net_is_ipv4_addr_bcast(struct net_if *iface,
+					  const struct in_addr *addr)
+{
+	if (net_ipv4_addr_cmp(addr, net_ipv4_broadcast_address())) {
+		return true;
+	}
+
+	return net_if_ipv4_is_addr_bcast(iface, addr);
+}
+
+extern struct net_if_addr *net_if_ipv4_addr_lookup(const struct in_addr *addr,
+						   struct net_if **iface);
+
+/**
+ * @brief Check if the IPv4 address is assigned to any network interface
+ * in the system.
+ *
+ * @param addr A valid pointer on an IPv4 address
+ *
+ * @return True if IPv4 address is found in one of the network interfaces,
+ * False otherwise.
+ */
+static inline bool net_is_my_ipv4_addr(const struct in_addr *addr)
+{
+	bool ret;
+
+	ret = net_if_ipv4_addr_lookup(addr, NULL) != NULL;
+	if (!ret) {
+		ret = net_is_ipv4_addr_bcast(NULL, addr);
+	}
+
+	return ret;
+}
+
 /**
  *  @brief Check if the IPv6 address is unspecified (all bits zero)
  *

subsys/net/ip/Kconfig.ipv4

@@ -37,6 +37,13 @@ config NET_IF_MCAST_IPV4_ADDR_COUNT
 	int "Max number of multicast IPv4 addresses per network interface"
 	default 1
 
+config NET_ICMPV4_ACCEPT_BROADCAST
+	bool "Accept broadcast ICMPv4 echo-request"
+	default y
+	help
+	  If set, then respond to ICMPv4 echo-request that is sent to
+	  broadcast address.
+
 config NET_DHCPV4
 	bool "Enable DHCPv4 client"
 	depends on NET_IPV4

subsys/net/ip/icmpv4.c

@@ -110,7 +110,8 @@ static inline enum net_verdict icmpv4_handle_echo_request(struct net_pkt *pkt)
 
 	net_ipaddr_copy(&addr, &NET_IPV4_HDR(pkt)->src);
 	net_ipaddr_copy(&NET_IPV4_HDR(pkt)->src,
-			&NET_IPV4_HDR(pkt)->dst);
+			net_if_ipv4_select_src_addr(net_pkt_iface(pkt),
+						    &addr));
 	net_ipaddr_copy(&NET_IPV4_HDR(pkt)->dst, &addr);
 
 	icmp_hdr.type = NET_ICMPV4_ECHO_REPLY;
@@ -121,10 +122,7 @@ static inline enum net_verdict icmpv4_handle_echo_request(struct net_pkt *pkt)
 		return NET_DROP;
 	}
 
-	ret = net_icmpv4_set_chksum(pkt);
-	if (ret < 0) {
-		return NET_DROP;
-	}
+	net_ipv4_finalize(pkt, IPPROTO_ICMP);
 
 	NET_DBG("Sending Echo Reply from %s to %s",
 		log_strdup(net_sprint_ipv4_addr(&NET_IPV4_HDR(pkt)->src)),
@@ -342,6 +340,15 @@ enum net_verdict net_icmpv4_input(struct net_pkt *pkt)
 		return NET_DROP;
 	}
 
+	if (net_is_ipv4_addr_bcast(net_pkt_iface(pkt),
+				   &NET_IPV4_HDR(pkt)->dst)) {
+		if (!IS_ENABLED(CONFIG_NET_ICMPV4_ACCEPT_BROADCAST) ||
+		    icmp_hdr.type != NET_ICMPV4_ECHO_REQUEST) {
+			NET_DBG("Dropping broadcast pkt");
+			goto drop;
+		}
+	}
+
 	NET_DBG("ICMPv4 packet received type %d code %d",
 		icmp_hdr.type, icmp_hdr.code);
 
@@ -354,6 +361,7 @@ enum net_verdict net_icmpv4_input(struct net_pkt *pkt)
 		}
 	}
 
+drop:
 	net_stats_update_icmp_drop(net_pkt_iface(pkt));
 
 	return NET_DROP;

subsys/net/ip/ipv4.c

@@ -122,6 +122,10 @@ enum net_verdict net_ipv4_process_pkt(struct net_pkt *pkt)
 		goto drop;
 	}
 
+	if (net_is_ipv4_addr_bcast(net_pkt_iface(pkt), &hdr->src)) {
+		goto drop;
+	}
+
 	NET_DBG("IPv4 packet received from %s to %s",
 		log_strdup(net_sprint_ipv4_addr(&hdr->src)),
 		log_strdup(net_sprint_ipv4_addr(&hdr->dst)));
@@ -151,6 +155,11 @@ enum net_verdict net_ipv4_process_pkt(struct net_pkt *pkt)
 		verdict = net_icmpv4_input(pkt);
 		break;
 	case IPPROTO_TCP:
+		if (net_is_ipv4_addr_bcast(net_pkt_iface(pkt), &hdr->dst)) {
+			goto drop;
+		}
+
+		/* Fall through */
 	case IPPROTO_UDP:
 		verdict = net_conn_input(hdr->proto, pkt);
 		break;

subsys/net/ip/net_core.c

@@ -211,7 +211,9 @@ static inline int check_ip_addr(struct net_pkt *pkt)
 		 * back to us.
 		 */
 		if (net_is_ipv4_addr_loopback(&NET_IPV4_HDR(pkt)->dst) ||
-		    net_is_my_ipv4_addr(&NET_IPV4_HDR(pkt)->dst)) {
+		    (net_is_ipv4_addr_bcast(net_pkt_iface(pkt),
+				     &NET_IPV4_HDR(pkt)->dst) == false &&
+		     net_is_my_ipv4_addr(&NET_IPV4_HDR(pkt)->dst))) {
 			struct in_addr addr;
 
 			/* Swap the addresses so that in receiving side

subsys/net/ip/net_if.c

@@ -2128,7 +2128,7 @@ struct net_if_router *net_if_ipv4_router_add(struct net_if *iface,
 }
 
 bool net_if_ipv4_addr_mask_cmp(struct net_if *iface,
-			       struct in_addr *addr)
+			       const struct in_addr *addr)
 {
 	struct net_if_ipv4 *ipv4 = iface->config.ip.ipv4;
 	u32_t subnet;
@@ -2138,24 +2138,63 @@ bool net_if_ipv4_addr_mask_cmp(struct net_if *iface,
 		return false;
 	}
 
-	subnet = ntohl(UNALIGNED_GET(&addr->s_addr)) &
-		ntohl(ipv4->netmask.s_addr);
+	subnet = UNALIGNED_GET(&addr->s_addr) & ipv4->netmask.s_addr;
 
 	for (i = 0; i < NET_IF_MAX_IPV4_ADDR; i++) {
 		if (!ipv4->unicast[i].is_used ||
 		    ipv4->unicast[i].address.family != AF_INET) {
 			continue;
 		}
 
-		if ((ntohl(ipv4->unicast[i].address.in_addr.s_addr) &
-		     ntohl(ipv4->netmask.s_addr)) == subnet) {
+		if ((ipv4->unicast[i].address.in_addr.s_addr &
+		     ipv4->netmask.s_addr) == subnet) {
 			return true;
 		}
 	}
 
 	return false;
 }
 
+static bool ipv4_is_broadcast_address(struct net_if *iface,
+				      const struct in_addr *addr)
+{
+	struct net_if_ipv4 *ipv4 = iface->config.ip.ipv4;
+
+	if (!ipv4) {
+		return false;
+	}
+
+	if (!net_if_ipv4_addr_mask_cmp(iface, addr)) {
+		return false;
+	}
+
+	if ((UNALIGNED_GET(&addr->s_addr) & ~ipv4->netmask.s_addr) ==
+	    ~ipv4->netmask.s_addr) {
+		return true;
+	}
+
+	return false;
+}
+
+bool net_if_ipv4_is_addr_bcast(struct net_if *iface,
+			       const struct in_addr *addr)
+{
+	if (iface) {
+		return ipv4_is_broadcast_address(iface, addr);
+	}
+
+	for (iface = __net_if_start; iface != __net_if_end; iface++) {
+		bool ret;
+
+		ret = ipv4_is_broadcast_address(iface, addr);
+		if (ret) {
+			return ret;
+		}
+	}
+
+	return false;
+}
+
 struct net_if *net_if_ipv4_select_src_iface(struct in_addr *dst)
 {
 	struct net_if *iface;

subsys/net/l2/ethernet/ethernet.c

@@ -242,8 +242,7 @@ static inline bool check_if_dst_is_broadcast_or_mcast(struct net_if *iface,
 {
 	struct net_eth_hdr *hdr = NET_ETH_HDR(pkt);
 
-	if (net_ipv4_addr_cmp(&NET_IPV4_HDR(pkt)->dst,
-			      net_ipv4_broadcast_address())) {
+	if (net_is_ipv4_addr_bcast(iface, &NET_IPV4_HDR(pkt)->dst)) {
 		/* Broadcast address */
 		net_pkt_lladdr_dst(pkt)->addr = (u8_t *)broadcast_eth_addr.addr;
 		net_pkt_lladdr_dst(pkt)->len = sizeof(struct net_eth_addr);

tests/net/ip-addr/src/main.c

@@ -371,8 +371,14 @@ static void test_ipv4_addresses(void)
 	struct in_addr match_addr = { { { 192, 168, 0, 2 } } };
 	struct in_addr fail_addr = { { { 10, 1, 0, 2 } } };
 	struct in_addr netmask = { { { 255, 255, 255, 0 } } };
+	struct in_addr netmask2 = { { { 255, 255, 0, 0 } } };
 	struct in_addr gw = { { { 192, 168, 0, 42 } } };
 	struct in_addr loopback4 = { { { 127, 0, 0, 1 } } };
+	struct in_addr bcast_addr1 = { { { 255, 255, 255, 255 } } };
+	struct in_addr bcast_addr2 = { { { 192, 168, 1, 255 } } };
+	struct in_addr bcast_addr3 = { { { 192, 168, 255, 255 } } };
+	struct in_addr bcast_addr4 = { { { 192, 0, 2, 255 } } };
+	struct in_addr bcast_addr5 = { { { 192, 168, 0, 255 } } };
 	struct net_if *iface, *iface1, *iface2;
 	int i, ret;
 
@@ -458,7 +464,7 @@ static void test_ipv4_addresses(void)
 		"IPv4 wrong match failed");
 
 	zassert_true(net_ipv4_addr_mask_cmp(iface, &match_addr),
-		"IPv4 match failed");
+		     "IPv4 match failed");
 
 	zassert_true(net_is_ipv4_addr_mcast(&maddr4a),
 		     "IPv4 multicast address");
@@ -504,6 +510,29 @@ static void test_ipv4_addresses(void)
 
 	ifmaddr1 = net_if_ipv4_maddr_lookup(&maddr4b, &iface1);
 	zassert_is_null(ifmaddr1, "IPv4 multicast address lookup succeed");
+
+	ret = net_is_ipv4_addr_bcast(iface, &bcast_addr1);
+	zassert_true(ret, "IPv4 address 1 is not broadcast address");
+
+	ret = net_is_ipv4_addr_bcast(iface, &bcast_addr2);
+	zassert_false(ret, "IPv4 address 2 is broadcast address");
+
+	ret = net_is_ipv4_addr_bcast(iface, &bcast_addr4);
+	zassert_false(ret, "IPv4 address 4 is broadcast address");
+
+	ret = net_is_ipv4_addr_bcast(iface, &maddr4b);
+	zassert_false(ret, "IPv4 address is broadcast address");
+
+	ret = net_is_ipv4_addr_bcast(iface, &bcast_addr5);
+	zassert_true(ret, "IPv4 address 5 is not broadcast address");
+
+	net_if_ipv4_set_netmask(iface, &netmask2);
+
+	ret = net_is_ipv4_addr_bcast(iface, &bcast_addr2);
+	zassert_false(ret, "IPv4 address 2 is broadcast address");
+
+	ret = net_is_ipv4_addr_bcast(iface, &bcast_addr3);
+	zassert_true(ret, "IPv4 address 3 is not broadcast address");
 }
 
 void test_main(void)