IPv6: STCP dual-stack + Android config + invite fixes

- stcp_server: dual-stack (AF_INET6 + IPV6_V6ONLY=0) instead of IPv4-only
- stcp_client: getaddrinfo(AF_UNSPEC) instead of inet_pton(AF_INET)
- stcp_link: detect address family from remote_addr->ss_family
- platform_compat.h: add <netdb.h> for getaddrinfo on POSIX
- ConfigProvider.kt: add [server:main6] addr=[::]:PORT for Android
- invite_link_c.c: invite_serialize_addrs handles IPv6 (was IPv4-only)

lib/platform_compat.h

@@ -166,6 +166,7 @@ extern "C" {
     #include <strings.h>
     #include <arpa/inet.h>
     #include <netinet/in.h>
+    #include <netdb.h>
     #include <fcntl.h>
     #include <unistd.h>
     #include <poll.h>

src/routing_layer/conn_mgr.h

@@ -19,7 +19,10 @@ struct TOPO_GROUP;
  * @file conn_mgr.h
  * @brief Подключение к узлам P2P-сети. Handle-based API.
  *
- * === Архитектура ===
+ * Подключает к удалегному узлу либо напрямую, либо через посредника с прямыми адресами.
+ * При открытии выдаёт handle. и держит подключение открытым пока не закроешь handle.
+ * Отправлять можно обычным send через роутер - он сам разберётся как отправить,
+ * либо send этого моделя - он точно отправит через этот мост.
  *
  * Один CONN_MGR = одна TOPO_GROUP. Создаётся conn_mgr_init(group), живёт пока
  * существует группа. Внутри: кеш entries (по одной на целевой узел), список

src/transport_layer/stcp_client.c

@@ -258,16 +258,23 @@ struct stcp_client *stcp_client_connect(struct UASYNC *ua, const char *addr, uin
     c->on_close = close_cb; c->close_arg = close_arg;
     c->tx_cb = client_tx_queue_cb;
 
-    c->sock = socket(AF_INET, SOCK_STREAM, 0);
-    if (c->sock == SOCKET_INVALID) { u_free(cli); return NULL; }
+    struct addrinfo hints = {0};
+    hints.ai_family = AF_UNSPEC;
+    hints.ai_socktype = SOCK_STREAM;
+    char port_str[16]; snprintf(port_str, sizeof(port_str), "%u", port);
+    struct addrinfo *res;
+    if (getaddrinfo(addr, port_str, &hints, &res) != 0) {
+        DEBUG_ERROR(DEBUG_CATEGORY_SOCKET, "stcp_client getaddrinfo %s:%u failed", addr, port);
+        u_free(cli); return NULL;
+    }
+    c->sock = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
+    if (c->sock == SOCKET_INVALID) { freeaddrinfo(res); u_free(cli); return NULL; }
     socket_set_nonblocking(c->sock);
-    struct sockaddr_in saddr; memset(&saddr, 0, sizeof(saddr));
-    saddr.sin_family = AF_INET; saddr.sin_port = htons(port);
-    if (inet_pton(AF_INET, addr, &saddr.sin_addr) != 1) { socket_close_wrapper(c->sock); u_free(cli); return NULL; }
-    if (connect(c->sock, (struct sockaddr *)&saddr, sizeof(saddr)) < 0 && socket_get_error() != EINPROGRESS) {
+    if (connect(c->sock, res->ai_addr, res->ai_addrlen) < 0 && socket_get_error() != EINPROGRESS) {
         DEBUG_ERROR(DEBUG_CATEGORY_SOCKET, "stcp_client connect to %s:%u failed err=%d", addr, port, socket_get_error());
-        socket_close_wrapper(c->sock); u_free(cli); return NULL;
+        socket_close_wrapper(c->sock); freeaddrinfo(res); u_free(cli); return NULL;
     }
+    freeaddrinfo(res);
     c->socket_id = uasync_add_socket_t(ua, c->sock, NULL, client_connect_write_cb, NULL, cli);
     if (!c->socket_id) { socket_close_wrapper(c->sock); u_free(cli); return NULL; }
     return cli;

src/transport_layer/stcp_link.c

@@ -133,10 +133,21 @@ struct stcp_link *stcp_link_connect(struct stcp_link_config *cfg) {
     if (!cfg || !cfg->ua || !cfg->my_keys || !cfg->peer_pubkey || !cfg->remote_addr)
         return NULL;
 
+    int family = cfg->remote_addr->ss_family;
     char addr_str[64];
-    struct sockaddr_in *sa = (struct sockaddr_in *)cfg->remote_addr;
-    inet_ntop(AF_INET, &sa->sin_addr, addr_str, sizeof(addr_str));
-    uint16_t port = cfg->remote_port ? cfg->remote_port : ntohs(sa->sin_port);
+    uint16_t port;
+    if (family == AF_INET) {
+        struct sockaddr_in *sa = (struct sockaddr_in *)cfg->remote_addr;
+        inet_ntop(AF_INET, &sa->sin_addr, addr_str, sizeof(addr_str));
+        port = cfg->remote_port ? cfg->remote_port : ntohs(sa->sin_port);
+    } else if (family == AF_INET6) {
+        struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *)cfg->remote_addr;
+        inet_ntop(AF_INET6, &sa6->sin6_addr, addr_str, sizeof(addr_str));
+        port = cfg->remote_port ? cfg->remote_port : ntohs(sa6->sin6_port);
+    } else {
+        DEBUG_ERROR(DEBUG_CATEGORY_SOCKET, "stcp_link: unsupported address family %d", family);
+        return NULL;
+    }
 
     struct stcp_link *link = u_calloc(1, sizeof(struct stcp_link));
     if (!link) return NULL;

src/transport_layer/stcp_server.c

@@ -355,16 +355,18 @@ struct stcp_server *stcp_server_create(struct UASYNC *ua, uint16_t port,
     srv->close_cb = close_cb;
     srv->close_arg = close_arg;
 
-    srv->listen_sock = socket(AF_INET, SOCK_STREAM, 0);
+    srv->listen_sock = socket(AF_INET6, SOCK_STREAM, 0);
     if (srv->listen_sock == SOCKET_INVALID) { DEBUG_ERROR(DEBUG_CATEGORY_SOCKET, "socket failed"); u_free(srv); return NULL; }
     socket_set_nonblocking(srv->listen_sock);
     int reuse = 1;
     setsockopt(srv->listen_sock, SOL_SOCKET, SO_REUSEADDR, (const char *)&reuse, sizeof(reuse));
-    struct sockaddr_in addr;
+    int v6only = 0;
+    setsockopt(srv->listen_sock, IPPROTO_IPV6, IPV6_V6ONLY, (const char *)&v6only, sizeof(v6only));
+    struct sockaddr_in6 addr;
     memset(&addr, 0, sizeof(addr));
-    addr.sin_family = AF_INET;
-    addr.sin_addr.s_addr = INADDR_ANY;
-    addr.sin_port = htons(port);
+    addr.sin6_family = AF_INET6;
+    addr.sin6_addr = in6addr_any;
+    addr.sin6_port = htons(port);
     if (bind(srv->listen_sock, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
         DEBUG_ERROR(DEBUG_CATEGORY_SOCKET, "bind port=%u failed err=%d", port, socket_get_error());
         socket_close_wrapper(srv->listen_sock); u_free(srv); return NULL;

tools/chatgui-android/app/src/main/java/com/utun/chat/data/ConfigProvider.kt

@@ -290,6 +290,9 @@ class ConfigProvider(private val context: Context) {
             appendLine("[server:main]")
             appendLine("addr=0.0.0.0:$listenPort")
             appendLine()
+            appendLine("[server:main6]")
+            appendLine("addr=[::]:$listenPort")
+            appendLine()
             appendLine("[allowed_keys]")
             appendLine("allow_all=yes")
             appendLine()

tools/chatgui-android/libutun_lite/invite_link_c.c

@@ -127,16 +127,16 @@ int invite_serialize_addrs(const struct InviteDataC* data, uint8_t* buf, size_t
     if (!data || !buf) return -1;
     size_t needed = 0;
     for (int i = 0; i < (int)data->addrCount; i++)
-        needed += 9U;  /* family(1) + sockId(1) + proto(1) + ip4(4) + port(2) = 9; IPv6 skipped */
+        needed += (data->addrs[i].family == 6) ? 21U : 9U;
     if (needed > buf_size) return -1;
     size_t pos = 0;
     for (int i = 0; i < (int)data->addrCount; i++) {
         const struct InviteAddrC* a = &data->addrs[i];
-        if (a->family != 4) continue;
+        int ip_len = (a->family == 6) ? 16 : 4;
         buf[pos++] = (uint8_t)a->family;
         buf[pos++] = a->socketId;
         buf[pos++] = a->proto;
-        memcpy(buf + pos, a->address, 4); pos += 4;
+        memcpy(buf + pos, a->address, (size_t)ip_len); pos += ip_len;
         buf[pos++] = (uint8_t)(a->port >> 8);
         buf[pos++] = (uint8_t)(a->port & 0xFF);
     }