Add timeout send/recv and multicast client/server socket examples (#1519)

Add a couple of socket examples that can be used with WAMR:
- The `timeout_client` and `timeout_server` examples demonstrate socket
  send and receive timeouts using the socket options
- The `multicast_client` and `multicast_server` examples demonstrate receiving
  multicast packets in WASM

And add several macro controls for `socket_opts` example.

Author: cimacmillan

core/iwasm/libraries/lib-socket/src/wasi/wasi_socket_ext.c

@@ -692,12 +692,12 @@ get_ipproto_ip_option(int sockfd, int optname, void *__restrict optval,
             HANDLE_ERROR(error);
             return error;
         case IP_TTL:
-            assert(*optlen == sizeof(uint8_t));
+            assert(*optlen == sizeof(int));
             error = __wasi_sock_get_ip_ttl(sockfd, (uint8_t *)optval);
             HANDLE_ERROR(error);
             return error;
         case IP_MULTICAST_TTL:
-            assert(*optlen == sizeof(uint8_t));
+            assert(*optlen == sizeof(int));
             error = __wasi_sock_get_ip_multicast_ttl(sockfd, (uint8_t *)optval);
             HANDLE_ERROR(error);
             return error;
@@ -915,12 +915,12 @@ set_ipproto_ip_option(int sockfd, int optname, const void *optval,
             HANDLE_ERROR(error);
             return error;
         case IP_TTL:
-            assert(optlen == sizeof(uint8_t));
+            assert(optlen == sizeof(int));
             error = __wasi_sock_set_ip_ttl(sockfd, *(uint8_t *)optval);
             HANDLE_ERROR(error);
             return error;
         case IP_MULTICAST_TTL:
-            assert(optlen == sizeof(uint8_t));
+            assert(optlen == sizeof(int));
             error =
                 __wasi_sock_set_ip_multicast_ttl(sockfd, *(uint8_t *)optval);
             HANDLE_ERROR(error);

samples/socket-api/CMakeLists.txt

@@ -94,6 +94,10 @@ ExternalProject_Add(wasm-app
                       socket_opts.wasm ${CMAKE_BINARY_DIR}
                       udp_client.wasm ${CMAKE_BINARY_DIR}
                       udp_server.wasm ${CMAKE_BINARY_DIR}
+                      multicast_client.wasm ${CMAKE_BINARY_DIR}
+                      multicast_server.wasm ${CMAKE_BINARY_DIR}
+                      timeout_client.wasm ${CMAKE_BINARY_DIR}
+                      timeout_server.wasm ${CMAKE_BINARY_DIR}
 )
 
 add_executable(tcp_server ${CMAKE_CURRENT_SOURCE_DIR}/wasm-src/tcp_server.c)
@@ -112,6 +116,14 @@ add_executable(udp_client ${CMAKE_CURRENT_SOURCE_DIR}/wasm-src/udp_client.c)
 
 add_executable(udp_server ${CMAKE_CURRENT_SOURCE_DIR}/wasm-src/udp_server.c)
 
+add_executable(multicast_client ${CMAKE_CURRENT_SOURCE_DIR}/wasm-src/multicast_client.c)
+
+add_executable(multicast_server ${CMAKE_CURRENT_SOURCE_DIR}/wasm-src/multicast_server.c)
+
+add_executable(timeout_client ${CMAKE_CURRENT_SOURCE_DIR}/wasm-src/timeout_client.c)
+
+add_executable(timeout_server ${CMAKE_CURRENT_SOURCE_DIR}/wasm-src/timeout_server.c)
+
 ############################################
 ## Build iwasm with wasi and pthread support
 ############################################

samples/socket-api/README.md

@@ -93,20 +93,73 @@ Data:
 
 `socket_opts.wasm` shows an example of getting and setting various supported socket options
 ```bash
-$ ./iwasm ./socket_opts.wasm
+$ ./iwasm socket_opts.wasm
 ```
-
-The output describes the different socket options that are set & retrieved, like so:
+The output is:
 ```bash
 [Client] Create TCP socket
 [Client] Create UDP socket
 [Client] Create UDP IPv6 socket
-SO_RCVTIMEO tv_sec is expected
-SO_RCVTIMEO tv_usec is expected
+setsockopt SO_RCVTIMEO result is expected
+getsockopt SO_RCVTIMEO result is expected
 ...
 [Client] Close sockets
 ```
 
+The `timeout_client.wasm` and `timeout_server.wasm` examples demonstrate socket send and receive timeouts using the socket options. Start the server, then start the client.
+
+```bash
+$ ./iwasm --addr-pool=0.0.0.0/15 timeout_server.wasm
+```
+
+The output is:
+
+```bash
+Wait for client to connect
+Client connected, sleeping for 10s
+Shuting down
+```
+
+```bash
+$ ./iwasm --addr-pool=127.0.0.1/15 --heap-size=10000000 timeout_client.wasm
+```
+
+The output is:
+
+```bash
+Waiting on recv, which should timeout
+Waiting on send, which should timeout
+Success. Closing socket 
+```
+
+The `multicast_client` and `multicast_server` examples demonstrate receiving multicast packets in WASM. Start the client and then the server with a multicast IP address and port. 
+
+```bash
+$ ./iwasm --addr-pool=0.0.0.0/0,::/0 multicast_client.wasm <Multicast IP> <Port>
+$ ./iwasm --addr-pool=0.0.0.0/0,::/0 multicast_client.wasm 224.0.0.1
+$ ./iwasm --addr-pool=0.0.0.0/0,::/0 multicast_client.wasm FF02:113D:6FDD:2C17:A643:FFE2:1BD1:3CD2
+```
+
+The output should be
+
+```bash
+Joined multicast group. Waiting for datagram...
+Reading datagram message...OK.
+The message from multicast server is: "Test message"
+```
+
+```bash
+$ ./multicast_server <Multicast IP> <Port>
+$ ./multicast_server 224.0.0.1
+$ ./multicast_server FF02:113D:6FDD:2C17:A643:FFE2:1BD1:3CD2
+```
+
+The output should be
+
+```bash
+Datagram sent
+```
+
 ### Domain name server resolution
 
 `addr_resolve.wasm` demonstrates the usage of resolving a domain name

samples/socket-api/wasm-src/CMakeLists.txt

@@ -83,3 +83,7 @@ compile_with_clang(addr_resolve.c)
 compile_with_clang(socket_opts.c)
 compile_with_clang(udp_client.c)
 compile_with_clang(udp_server.c)
+compile_with_clang(multicast_client.c)
+compile_with_clang(multicast_server.c)
+compile_with_clang(timeout_client.c)
+compile_with_clang(timeout_server.c)

samples/socket-api/wasm-src/multicast_client.c

@@ -0,0 +1,135 @@
+/*
+ * Copyright (C) 2022 Amazon.com Inc. or its affiliates. All rights reserved.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+ */
+
+#include <arpa/inet.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <unistd.h>
+#ifdef __wasi__
+#include <wasi_socket_ext.h>
+#endif
+
+static void
+init_sockaddr_inet(struct sockaddr_in *addr)
+{
+    addr->sin_family = AF_INET;
+    addr->sin_port = htons(1234);
+}
+
+static void
+init_sockaddr_inet6(struct sockaddr_in6 *addr)
+{
+    addr->sin6_family = AF_INET6;
+    addr->sin6_port = htons(1234);
+}
+
+static int
+get_ip_addr_type(char *addr, char *buf)
+{
+    if (inet_pton(AF_INET6, addr, buf)) {
+        return AF_INET6;
+    }
+    if (inet_pton(AF_INET, addr, buf)) {
+        return AF_INET;
+    }
+    return -1;
+}
+
+static int
+is_valid_addr_type(int addr_type)
+{
+    return !(addr_type == -1
+             || (addr_type != AF_INET && addr_type != AF_INET6));
+}
+
+int
+main(int argc, char *argv[])
+{
+    struct ipv6_mreq ipv6_group;
+    struct ip_mreq ipv4_group;
+    int sd;
+    int datalen;
+    char databuf[1024];
+    char multicast_addr_buffer[16];
+    struct sockaddr_storage local_address = { 0 };
+    int addr_type = -1;
+    int read_result;
+    int bool_opt = 1;
+
+    if (argc < 2) {
+        printf("Usage is <Multicast IP>\n");
+        return EXIT_FAILURE;
+    }
+
+    addr_type = get_ip_addr_type(argv[1], multicast_addr_buffer);
+
+    if (!is_valid_addr_type(addr_type)) {
+        printf("Not a valid ipv4 or ipv6 address\n");
+        return EXIT_FAILURE;
+    }
+
+    if ((sd = socket(addr_type, SOCK_DGRAM, 0)) == -1) {
+        perror("Failed opening socket");
+        return EXIT_FAILURE;
+    }
+
+    if (setsockopt(sd, SOL_SOCKET, SO_REUSEADDR, &bool_opt, sizeof(bool_opt))
+        == -1) {
+        perror("Failed setting SO_REUSEADDR");
+        goto fail;
+    }
+
+    if (addr_type == AF_INET) {
+        init_sockaddr_inet((struct sockaddr_in *)&local_address);
+        memcpy(&(ipv4_group.imr_multiaddr), multicast_addr_buffer, 4);
+        ipv4_group.imr_interface.s_addr = htonl(INADDR_ANY);
+
+        if (setsockopt(sd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &ipv4_group,
+                       sizeof(ipv4_group))
+            == -1) {
+            perror("Failed joining IPv4 multicast group");
+            goto fail;
+        }
+    }
+    else {
+        init_sockaddr_inet6((struct sockaddr_in6 *)&local_address);
+        memcpy(&(ipv6_group.ipv6mr_multiaddr), multicast_addr_buffer, 16);
+        ipv6_group.ipv6mr_interface = 0;
+
+        if (setsockopt(sd, IPPROTO_IPV6, IPV6_JOIN_GROUP, &ipv6_group,
+                       sizeof(ipv6_group))
+            == -1) {
+            perror("Failed joining IPv6 multicast group");
+            goto fail;
+        }
+    }
+
+    if (bind(sd, (struct sockaddr *)&local_address, sizeof(local_address))
+        == -1) {
+        perror("Failed binding socket");
+        goto fail;
+    }
+
+    printf("Joined multicast group. Waiting for datagram...\n");
+
+    datalen = sizeof(databuf);
+    read_result = read(sd, databuf, datalen);
+
+    if (read_result < 0) {
+        perror("Failed binding socket");
+        goto fail;
+    }
+
+    printf("Reading datagram message...OK.\n");
+    printf("The message from multicast server is: \"%s\"\n", databuf);
+    close(sd);
+    return EXIT_SUCCESS;
+
+fail:
+    close(sd);
+    return EXIT_FAILURE;
+}