examples: add socket stdin utils to common connect component

* Original commit: espressif/esp-idf@a5a750ba48

examples/common_components/protocol_examples_common/addr_from_stdin.c

@@ -0,0 +1,65 @@
+#include <string.h>
+#include "esp_system.h"
+#include "esp_log.h"
+#include "esp_netif.h"
+#include "protocol_examples_common.h"
+
+#include "lwip/sockets.h"
+#include <lwip/netdb.h>
+#include <arpa/inet.h>
+
+#define HOST_IP_SIZE 128
+
+esp_err_t get_addr_from_stdin(int port, int sock_type, int *ip_protocol, int *addr_family, struct sockaddr_in6 *dest_addr)
+{
+    char host_ip[HOST_IP_SIZE];
+    int len;
+    static bool already_init = false;
+
+    // this function could be called multiple times -> make sure UART init runs only once
+    if (!already_init) {
+        example_configure_stdin_stdout();
+        already_init = true;
+    }
+
+    // ignore empty or LF only string (could receive from DUT class)
+    do {
+        fgets(host_ip, HOST_IP_SIZE, stdin);
+        len = strlen(host_ip);
+    } while (len<=1 && host_ip[0] == '\n');
+    host_ip[len - 1] = '\0';
+
+    struct addrinfo hints, *addr_list, *cur;
+    memset( &hints, 0, sizeof( hints ) );
+
+    // run getaddrinfo() to decide on the IP protocol
+    hints.ai_family = AF_UNSPEC;
+    hints.ai_socktype = sock_type;
+    hints.ai_protocol = IPPROTO_TCP;
+    if( getaddrinfo( host_ip, NULL, &hints, &addr_list ) != 0 ) {
+        return ESP_FAIL;
+    }
+    for( cur = addr_list; cur != NULL; cur = cur->ai_next ) {
+        memcpy(dest_addr, cur->ai_addr, sizeof(*dest_addr));
+        if (cur->ai_family == AF_INET) {
+            *ip_protocol = IPPROTO_IP;
+            *addr_family = AF_INET;
+            // add port number and return on first IPv4 match
+            ((struct sockaddr_in*)dest_addr)->sin_port = htons(port);
+            freeaddrinfo( addr_list );
+            return ESP_OK;
+
+        } else if (cur->ai_family == AF_INET6) {
+            *ip_protocol = IPPROTO_IPV6;
+            *addr_family = AF_INET6;
+            // add port and interface number and return on first IPv6 match
+            dest_addr->sin6_port = htons(port);
+            dest_addr->sin6_scope_id = esp_netif_get_netif_impl_index(EXAMPLE_INTERFACE);
+            freeaddrinfo( addr_list );
+            return ESP_OK;
+        }
+    }
+    // no match found
+    freeaddrinfo( addr_list );
+    return ESP_FAIL;
+}