utun2/tests/test_etcp_router_unit.c

// test_etcp_router_unit.c — Юнит-тест etcp_router: reorder, seq, ACK, conn lifecycle
// Без ETCP-соединений, без сокетов, без BGP.
// Инжектит SVC_ROUTE пакеты напрямую через etcp_router_recv_cb из api_bindings.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <sys/time.h>

#include "etcp.h"
#include "etcp_api.h"
#include "etcp_router.h"
#include "topo_group.h"
#include "../src/utun_instance.h"
#include "../lib/u_async.h"
#include "../lib/ll_queue.h"
#include "../lib/debug_config.h"
#include "../lib/mem.h"
#include "../src/transport_layer/secure_channel.h"
#include <openssl/sha.h>

#define TEST_SVC_ID 0x42
#define TEST_SVC_ID2 0x43
#define TEST_REMOTE_NODE 0xAAAA000000000001ULL
#define TEST_REMOTE_NODE2 0xAAAA000000000002ULL
#define TEST_E2E_PEER   0xEEEE000000000001ULL

// ======================== Test handler state ========================
static struct {
    int delivered;
    int errors;
    uint32_t expected_seq;
    uint32_t last_seq;
    uint8_t marker;
} rx;

static int g_notify_count = 0;

static void test_handler(struct ETCP_CONN* conn, struct ll_entry* entry) {
    (void)conn;
    if (!entry || !entry->dgram || entry->len < ROUTER_SVC_HDR_SIZE) {
        g_notify_count++;
        if (entry) { queue_dgram_free(entry); queue_entry_free(entry); }
        return;
    }
    // close/restart: [svc_id][src][dst] без payload
    if (entry->len == ROUTER_SVC_HDR_SIZE) {
        g_notify_count++;
        queue_dgram_free(entry); queue_entry_free(entry);
        return;
    }
    if (entry->dgram[ROUTER_SVC_PAYLOAD_OFF] != rx.marker) { rx.errors++; } else { rx.delivered++; rx.last_seq = rx.expected_seq; rx.expected_seq++; }
    queue_dgram_free(entry); queue_entry_free(entry);
}

static void rx_reset(uint8_t marker) {
    memset(&rx, 0, sizeof(rx));
    rx.marker = marker;
}

// ======================== Inject helper ========================
static struct ETCP_CONN fake_conn;

static void inject(etcp_recv_fn recv_cb, struct UTUN_INSTANCE* inst,
                   uint64_t src, uint8_t svc_id, uint32_t seq,
                   const uint8_t* pl, size_t pl_len, int is_ack, uint8_t flags) {
    struct SVC_ROUTE_HDR hdr;
    memset(&hdr, 0, sizeof(hdr));
    hdr.cmd         = ETCP_RT_ID_SVC_ROUTE;
    hdr.group_id    = TOPO_GROUP_UTUN;
    hdr.dst_node_id = inst->node_id;
    hdr.src_node_id = src;
    hdr.seq         = seq;
    hdr.svc_id      = svc_id;
    hdr.flags       = flags;

    size_t total = SVC_ROUTE_HDR_SIZE + (is_ack ? 0 : pl_len);
    struct ll_entry* e = queue_entry_new(0);
    if (!e) { printf("  inject: queue_entry_new failed\n"); return; }
    e->dgram = u_malloc(total);
    if (!e->dgram) { queue_entry_free(e); return; }
    memcpy(e->dgram, &hdr, SVC_ROUTE_HDR_SIZE);
    if (!is_ack && pl_len > 0)
        memcpy(e->dgram + SVC_ROUTE_HDR_SIZE, pl, pl_len);
    e->len = total;

    recv_cb(&fake_conn, e);
}

// ======================== Setup ========================
#define SETUP() do { \
    ua = uasync_create(); \
    if (!ua) { printf("  SETUP: uasync_create failed\n"); return -1; } \
    memset(&inst, 0, sizeof(inst)); \
    inst.ua = ua; \
    inst.node_id = 0xBBBB000000000001ULL; \
    debug_config_init(); \
    debug_set_level(DEBUG_LEVEL_ERROR); \
    debug_set_categories(DEBUG_CATEGORY_ALL); \
    memset(&fake_conn, 0, sizeof(fake_conn)); \
    fake_conn.instance = &inst; \
    TESTASSERT(etcp_router_init(&inst) == 0); \
    TESTASSERT(etcp_router_bind(&inst, TEST_SVC_ID, test_handler) == 0); \
    recv_cb = inst.api_bindings.callbacks[ETCP_RT_ID_SVC_ROUTE]; \
    TESTASSERT(recv_cb != NULL); \
} while(0)

#define TEARDOWN() do { \
    etcp_router_destroy(&inst); \
    uasync_destroy(ua, 0); \
    ua = NULL; \
} while(0)

// ======================== Macros ========================
static int test_total = 0, test_passed = 0, test_failed = 0;

#define TESTASSERT(cond) do { \
    if (!(cond)) { printf("  FAIL: %s:%d — %s\n", __FILE__, __LINE__, #cond); return -1; } \
} while(0)

#define TEST(name) do { \
    test_total++; \
    printf("TEST %d: %-50s ", test_total, name); fflush(stdout); \
} while(0)

#define PASS() do { puts("PASS"); test_passed++; } while(0)
#define FAIL(msg) do { printf("FAIL: %s\n", msg); test_failed++; return -1; } while(0)

// ======================== Sign test infrastructure ========================
static int              g_sign_ready = 0;
static struct SC_MYKEYS g_sign_keys;
static sc_context_t     g_sign_ctx;
static uint8_t          g_sign_ed25519_pubkey[SC_PUBKEY_SIZE];
static uint8_t          g_sign_ed25519_privkey[SC_PRIVKEY_SIZE];
static const uint64_t   SIGNER_NODE = 0xCCCC000000000001ULL;

static int setup_sign_keys(void) {
    if (g_sign_ready) return 0;
    if (sc_generate_keypair(&g_sign_keys) != SC_OK) { printf("  setup_sign_keys: generate_keypair failed\n"); return -1; }
    sc_init_ctx(&g_sign_ctx, &g_sign_keys);
    if (sc_derive_ed25519_pubkey(g_sign_keys.private_key, g_sign_ed25519_pubkey) != SC_OK) { printf("  setup_sign_keys: derive_ed25519_pubkey failed\n"); return -1; }
    { unsigned char h[SHA512_DIGEST_LENGTH]; SHA512(g_sign_keys.private_key, SC_PRIVKEY_SIZE, h); memcpy(g_sign_ed25519_privkey, h, SC_PRIVKEY_SIZE); }
    g_sign_ready = 1;
    return 0;
}

static void setup_bgp_for_sign_test(struct UTUN_INSTANCE* inst, int with_ed25519_key) {
    inst->topo_groups = u_calloc(1, sizeof(struct TOPO_GROUPS));
    if (!inst->topo_groups) { printf("  setup_bgp: topo_groups alloc failed\n"); return; }
    inst->topo_groups->group_list = queue_new(inst->ua, 16, 0, 8, "group_list_test");
    inst->topo_groups->node_registry = queue_new(inst->ua, BGP_NODES_HASH_SIZE, 0, 8, "node_registry_test");

    struct ll_entry* qe = queue_entry_new(sizeof(struct TOPO_GROUP));
    if (!qe) { printf("  setup_bgp: queue_entry_new failed\n"); return; }
    struct TOPO_GROUP* group = (struct TOPO_GROUP*)qe;
    memset((uint8_t*)group + sizeof(struct ll_entry), 0, sizeof(*group) - sizeof(struct ll_entry));
    group->instance = inst;
    group->group_id = TOPO_GROUP_UTUN;
    group->nodes = queue_new(inst->ua, BGP_NODES_HASH_SIZE,
        offsetof(struct TOPO_GROUP_NODE, node_id) - sizeof(struct ll_entry), 8, "group_nodes_test");
    if (!group->nodes) { printf("  setup_bgp: queue_new failed\n"); queue_entry_free(qe); return; }
    queue_data_put_with_index(inst->topo_groups->group_list, &group->ll);

    struct TOPO_GROUP_NODE* nq = u_calloc(1, sizeof(struct TOPO_GROUP_NODE));
    if (!nq) { printf("  setup_bgp: nq alloc failed\n"); return; }
    nq->ll.size = sizeof(struct TOPO_GROUP_NODE) - sizeof(struct ll_entry);
    struct TOPO_NODE* ni = u_calloc(1, sizeof(struct TOPO_NODE));
    if (!ni) { printf("  setup_bgp: ni alloc failed\n"); u_free(nq); return; }
    ni->group_ref_count = 1; ni->node_id = SIGNER_NODE;
    if (with_ed25519_key) memcpy(ni->ed25519_public_key, g_sign_ed25519_pubkey, SC_PUBKEY_SIZE);
    topo_node_registry_store(inst->topo_groups, ni);
    nq->node_id = ni->node_id;
    queue_data_put_with_index(group->nodes, &nq->ll);
}

static void teardown_bgp_for_sign_test(struct UTUN_INSTANCE* inst) {
    if (!inst || !inst->topo_groups) return;
    struct TOPO_GROUP* group = topo_groups_get_default(inst->topo_groups);
    if (group && group->nodes) {
        struct ll_entry* e;
        while ((e = queue_data_get(group->nodes)) != NULL) queue_entry_free(e);
        queue_free(group->nodes);
        group->nodes = NULL;
    }
    struct ll_entry* ge;
    while ((ge = queue_data_get(inst->topo_groups->group_list)) != NULL) queue_entry_free(ge);
    queue_free(inst->topo_groups->group_list);
    u_free(inst->topo_groups);
    inst->topo_groups = NULL;
}

static void inject_signed(etcp_recv_fn recv_cb, struct UTUN_INSTANCE* inst,
                          uint64_t src, uint8_t svc_id, uint32_t seq,
                          const uint8_t* pl, size_t pl_len, uint8_t flags,
                          int tamper_sig) {
    if (seq == 0) flags |= ROUTER_FLAG_START;
    size_t hdr_pl = SVC_ROUTE_HDR_SIZE + pl_len;
    size_t total  = hdr_pl + SC_SIGN_SIZE;
    uint8_t* dgram = u_malloc(total);
    if (!dgram) { printf("  inject_signed: u_malloc failed\n"); return; }

    struct SVC_ROUTE_HDR* hdr = (struct SVC_ROUTE_HDR*)dgram;
    memset(hdr, 0, SVC_ROUTE_HDR_SIZE);
    hdr->cmd         = ETCP_RT_ID_SVC_ROUTE;
    hdr->group_id    = TOPO_GROUP_UTUN;
    hdr->dst_node_id = inst->node_id;
    hdr->src_node_id = src;
    hdr->seq         = seq;
    hdr->svc_id      = svc_id;
    hdr->flags       = flags | ROUTER_FLAG_SIGNED;
    if (pl_len > 0) memcpy(dgram + SVC_ROUTE_HDR_SIZE, pl, pl_len);

    if (sc_ed25519_sign(g_sign_ed25519_privkey, dgram, hdr_pl, dgram + hdr_pl) != SC_OK) { u_free(dgram); return; }

    if (tamper_sig) dgram[hdr_pl] ^= 0x01;

    struct ll_entry* e = queue_entry_new(0);
    if (!e) { u_free(dgram); return; }
    e->dgram = dgram;
    e->len   = total;
    recv_cb(&fake_conn, e);
}

// ======================== Tests ========================

static int test_init_destroy(void) {
    TEST("init/destroy");
    struct UASYNC* ua = uasync_create();
    if (!ua) FAIL("uasync_create");
    struct UTUN_INSTANCE inst;
    memset(&inst, 0, sizeof(inst));
    inst.ua = ua;
    inst.node_id = 1;
    debug_config_init();
    debug_set_level(DEBUG_LEVEL_ERROR);
    debug_set_categories(DEBUG_CATEGORY_ALL);

    memset(&fake_conn, 0, sizeof(fake_conn));
    fake_conn.instance = &inst;

    if (etcp_router_init(&inst) != 0) FAIL("init");
    if (inst.router_conns == NULL) FAIL("router_conns NULL after init");
    if (inst.api_bindings.callbacks[ETCP_RT_ID_SVC_ROUTE] == NULL) FAIL("recv_cb not bound");

    etcp_router_destroy(&inst);
    if (inst.router_conns != NULL) FAIL("router_conns not NULL after destroy");
    if (inst.api_bindings.callbacks[ETCP_RT_ID_SVC_ROUTE] != NULL) FAIL("recv_cb still bound");

    uasync_destroy(ua, 0);
    PASS();
    return 0;
}

static int test_bind_unbind(void) {
    TEST("bind/unbind API");
    struct UASYNC* ua = uasync_create();
    struct UTUN_INSTANCE inst;
    memset(&inst, 0, sizeof(inst));
    inst.ua = ua;
    inst.node_id = 1;
    debug_config_init();
    debug_set_level(DEBUG_LEVEL_ERROR);
    debug_set_categories(DEBUG_CATEGORY_ALL);

    if (etcp_router_init(&inst) != 0) FAIL("init");

    // bind
    if (etcp_router_bind(&inst, 0xEE, test_handler) != 0) FAIL("bind");
    if (inst.router_bindings.callbacks[0xEE] != test_handler) FAIL("cb not set");
    // rebind (overwrite)
    if (etcp_router_bind(&inst, 0xEE, test_handler) != 0) FAIL("rebind");
    // unbind
    if (etcp_router_unbind(&inst, 0xEE) != 0) FAIL("unbind");
    if (inst.router_bindings.callbacks[0xEE] != NULL) FAIL("cb not cleared");
    // double unbind
    if (etcp_router_unbind(&inst, 0xEE) == 0) FAIL("double unbind should fail");
    // null args
    if (etcp_router_bind(NULL, 0, test_handler) == 0) FAIL("bind null inst");
    etcp_router_destroy(&inst);
    uasync_destroy(ua, 0);
    PASS();
    return 0;
}

static int test_conn_get_create(void) {
    TEST("conn_get — create");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();

    struct ETCP_ROUTER_CONN* c = etcp_router_conn_get(&inst, TOPO_GROUP_UTUN, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c) FAIL("conn_get returned NULL");
    if (c->remote_node_id != TEST_REMOTE_NODE) FAIL("wrong remote_node_id");
    if (c->svc_id != TEST_SVC_ID) FAIL("wrong svc_id");
    if (c->tx_seq != 0) FAIL("tx_seq != 0");
    if (c->rx_seq != 0) FAIL("rx_seq != 0");
    if (c->tx_acked != 0) FAIL("tx_acked != 0");
    if (c->last_sent_ack_seq != 0) FAIL("last_sent_ack_seq != 0");
    if (c->recv_q == NULL) FAIL("recv_q is NULL");
    if (c->last_dgram_ts == 0) FAIL("last_dgram_ts not set");
    if (c->ack_timer != NULL) FAIL("ack_timer set at creation");

    etcp_router_conn_close(c);
    TEARDOWN();
    PASS();
    return 0;
}

static int test_conn_get_reuse(void) {
    TEST("conn_get — reuse / different");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();

    struct ETCP_ROUTER_CONN* c1 = etcp_router_conn_get(&inst, TOPO_GROUP_UTUN, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c1) FAIL("c1 NULL");
    struct ETCP_ROUTER_CONN* c2 = etcp_router_conn_get(&inst, TOPO_GROUP_UTUN, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (c1 != c2) FAIL("reuse: different pointers");

    struct ETCP_ROUTER_CONN* c3 = etcp_router_conn_get(&inst, TOPO_GROUP_UTUN, TEST_REMOTE_NODE2, TEST_SVC_ID);
    if (c3 == c1) FAIL("different remote, same pointer");
    struct ETCP_ROUTER_CONN* c4 = etcp_router_conn_get(&inst, TOPO_GROUP_UTUN, TEST_REMOTE_NODE, TEST_SVC_ID2);
    if (c4 == c1) FAIL("different svc, same pointer");

    etcp_router_conn_close(c1);
    etcp_router_conn_close(c3);
    etcp_router_conn_close(c4);
    TEARDOWN();
    PASS();
    return 0;
}

static int test_conn_close(void) {
    TEST("conn_close — new after close");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();

    struct ETCP_ROUTER_CONN* c1 = etcp_router_conn_get(&inst, TOPO_GROUP_UTUN, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c1) FAIL("c1 NULL");
    c1->tx_seq = 99; // mark
    etcp_router_conn_close(c1);
    struct ETCP_ROUTER_CONN* c2 = etcp_router_conn_get(&inst, TOPO_GROUP_UTUN, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c2) FAIL("c2 NULL");
    if (c2->tx_seq != 0 || c2->rx_seq != 0) FAIL("not fresh after close+reopen");

    etcp_router_conn_close(c2);
    TEARDOWN();
    PASS();
    return 0;
}

// ======================== Seq/reorder tests ========================

static int test_in_order(void) {
    TEST("in-order delivery (seq 0,1,2)");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    struct ETCP_ROUTER_CONN* c = etcp_router_conn_get(&inst, TOPO_GROUP_UTUN, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c) FAIL("conn_get failed");

    rx_reset(0xAA);
    uint8_t data[] = { TEST_SVC_ID, 0xAA, 0 };
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, data + 1, 2, 0, ROUTER_FLAG_START);
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 1, data + 1, 2, 0, 0);
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 2, data + 1, 2, 0, 0);

    if (rx.delivered != 3) FAIL("delivered != 3");
    if (rx.errors != 0) FAIL("errors != 0");
    if (c->rx_seq != 3) FAIL("rx_seq != 3");

    etcp_router_conn_close(c);
    TEARDOWN();
    PASS();
    return 0;
}

static int test_out_of_order(void) {
    TEST("out-of-order (0,2,3 then 1 → assembly to 3)");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    struct ETCP_ROUTER_CONN* c = etcp_router_conn_get(&inst, TOPO_GROUP_UTUN, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c) FAIL("conn_get failed");

    rx_reset(0xBB);
    uint8_t data[] = { TEST_SVC_ID, 0xBB, 0 };
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, data + 1, 2, 0, ROUTER_FLAG_START);
    if (rx.delivered != 1) FAIL("after seq 0: delivered != 1");
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 2, data + 1, 2, 0, 0);
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 3, data + 1, 2, 0, 0);
    if (rx.delivered != 1) FAIL("after seq 2,3: still delivered != 1 (gap at 1)");

    // Fill the gap
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 1, data + 1, 2, 0, 0);
    if (rx.delivered != 4) FAIL("after seq 1 fill: delivered != 4");
    if (rx.errors   != 0) FAIL("errors != 0");
    if (c->rx_seq   != 4) FAIL("rx_seq != 4");

    etcp_router_conn_close(c);
    TEARDOWN();
    PASS();
    return 0;
}

static int test_duplicate_same(void) {
    TEST("duplicate — same seq injected twice");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    struct ETCP_ROUTER_CONN* c = etcp_router_conn_get(&inst, TOPO_GROUP_UTUN, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c) FAIL("conn_get failed");

    rx_reset(0xCC);
    uint8_t data[] = { TEST_SVC_ID, 0xCC, 0 };
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, data + 1, 2, 0, ROUTER_FLAG_START);
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 1, data + 1, 2, 0, 0);
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 1, data + 1, 2, 0, 0); // dup

    if (rx.delivered != 2) FAIL("delivered != 2 (dup dropped)");
    if (c->rx_seq   != 2) FAIL("rx_seq != 2");

    etcp_router_conn_close(c);
    TEARDOWN();
    PASS();
    return 0;
}

static int test_duplicate_past(void) {
    TEST("duplicate — past seq (already delivered)");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    struct ETCP_ROUTER_CONN* c = etcp_router_conn_get(&inst, TOPO_GROUP_UTUN, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c) FAIL("conn_get failed");

    rx_reset(0xDD);
    uint8_t data[] = { TEST_SVC_ID, 0xDD, 0 };
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, data + 1, 2, 0, ROUTER_FLAG_START);
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 1, data + 1, 2, 0, 0);
    if (rx.delivered != 2) FAIL("delivered != 2");
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, data + 1, 2, 0, 0); // past

    if (rx.delivered != 2) FAIL("delivered != 2 (past dup dropped)");
    if (c->rx_seq   != 2) FAIL("rx_seq != 2");

    etcp_router_conn_close(c);
    TEARDOWN();
    PASS();
    return 0;
}

static int test_out_of_bounds(void) {
    TEST("out of bounds — seq too far ahead");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    struct ETCP_ROUTER_CONN* c = etcp_router_conn_get(&inst, TOPO_GROUP_UTUN, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c) FAIL("conn_get failed");

    rx_reset(0xEE);
    uint8_t data[] = { TEST_SVC_ID, 0xEE, 0 };
    /* first packet syncs rx_seq (peer_sync_done), then OOB check works */
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, data + 1, 2, 0, ROUTER_FLAG_START);
    uint32_t bad_seq = ROUTER_MAX_INFLIGHT + 2;
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, bad_seq, data + 1, 2, 0, 0);

    if (rx.delivered != 1) FAIL("first packet not delivered");
    if (c->rx_seq   != 1) FAIL("rx_seq should advance to 1 after first");

    etcp_router_conn_close(c);
    TEARDOWN();
    PASS();
    return 0;
}

static int test_circular_wrap(void) {
    TEST("32-bit circular wrap-around");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    struct ETCP_ROUTER_CONN* c = etcp_router_conn_get(&inst, TOPO_GROUP_UTUN, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c) FAIL("conn_get failed");

    c->rx_seq = 0xFFFFFFFE;
    c->peer_sync_done = 1;// сессия уже установлена (seq вручную на границе wrap)
    rx_reset(0x11);
    rx.expected_seq = 0xFFFFFFFE;
    uint8_t data[] = { TEST_SVC_ID, 0x11, 0 };
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0xFFFFFFFE, data + 1, 2, 0, 0);
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0xFFFFFFFF, data + 1, 2, 0, 0);
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0,            data + 1, 2, 0, 0);
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 1,            data + 1, 2, 0, 0);

    if (rx.delivered != 4) FAIL("delivered != 4 (wrap)");
    if (c->rx_seq   != 2) FAIL("rx_seq != 2 after wrap (wrapped)");

    etcp_router_conn_close(c);
    TEARDOWN();
    PASS();
    return 0;
}

static int test_data_integrity(void) {
    TEST("data integrity — payload preserved");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    struct ETCP_ROUTER_CONN* c = etcp_router_conn_get(&inst, TOPO_GROUP_UTUN, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c) FAIL("conn_get failed");

    rx_reset(0x77);
    uint8_t payload[10] = { 0x77, 0xA1, 0xB2, 0xC3, 0xD4, 0xE5, 0xF6, 0x07, 0x18, 0x29 };
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, payload, 10, 0, ROUTER_FLAG_START);

    if (rx.delivered != 1) FAIL("delivered != 1");
    if (rx.errors   != 0) FAIL("data mismatch");

    etcp_router_conn_close(c);
    TEARDOWN();
    PASS();
    return 0;
}

static int test_ack_receive(void) {
    TEST("ACK receive — tx_acked updated");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    struct ETCP_ROUTER_CONN* c = etcp_router_conn_get(&inst, TOPO_GROUP_UTUN, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c) FAIL("conn_get failed");

    rx_reset(0x00);
    // Send ACK: is_ack=1, seq=7 means remote has rx_seq=7
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 7, NULL, 0, 1, 0);

    if (c->tx_acked != 7)      FAIL("tx_acked not updated from ACK");
    if (rx.delivered != 0)     FAIL("ACK delivered to handler (should not)");
    if (c->last_dgram_ts == 0) FAIL("last_dgram_ts not updated on ACK");

    etcp_router_conn_close(c);
    TEARDOWN();
    PASS();
    return 0;
}

static int test_ack_timer(void) {
    TEST("ACK timer scheduled on data receive");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    struct ETCP_ROUTER_CONN* c = etcp_router_conn_get(&inst, TOPO_GROUP_UTUN, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c) FAIL("conn_get failed");

    if (c->ack_timer != NULL) FAIL("ack_timer set before any data");

    rx_reset(0x55);
    uint8_t data[] = { TEST_SVC_ID, 0x55, 0 };
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, data + 1, 2, 0, ROUTER_FLAG_START);

    if (c->ack_timer != NULL) FAIL("ack_timer set without BGP route");
    if (c->last_sent_ack_seq != 0) FAIL("last_sent_ack_seq changed without BGP route");

    etcp_router_conn_close(c);
    TEARDOWN();
    PASS();
    return 0;
}

static int test_send_q(void) {
    TEST("send_q — inflight full queues, not lost");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    struct ETCP_ROUTER_CONN* c = etcp_router_conn_get(&inst, TOPO_GROUP_UTUN, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c) FAIL("conn_get failed");

    // Заполняем inflight_q до лимита — канал «загружен»
    for (int i = 0; i < ROUTER_MAX_INFLIGHT; i++) {
        struct ROUTER_INFLIGHT* inf = u_malloc(sizeof(struct ROUTER_INFLIGHT));
        if (!inf) FAIL("inflight alloc");
        memset(&inf->ll, 0, sizeof(inf->ll));
        inf->ll.size = 4; inf->seq = (uint32_t)i; *(uint32_t*)inf->ll.data = (uint32_t)i;
        inf->dgram = u_malloc(1); inf->dgram_len = 1;
        queue_data_put_with_index(c->inflight_q, &inf->ll);
    }
    if (c->send_q == NULL) FAIL("send_q is NULL");

    // Send via conn_send — should queue, not drop
    uint8_t data[4] = { 1, 2, 3, 4 };
    int ret = etcp_router_conn_send(c, data, sizeof(data), 0);
    if (ret != 0) FAIL("conn_send should return 0 (queued in send_q)");
    if (c->send_blocked == 0) FAIL("send_blocked not set");
    if (c->watchdog_timer == NULL) FAIL("watchdog_timer not set");
    if (queue_entry_count(c->send_q) != 1) FAIL("send_q count != 1");
    if (c->tx_seq != 1) FAIL("tx_seq should advance to 1 at enqueue");

    // Cancel timers manually
    if (c->watchdog_timer) { uasync_cancel_timeout(ua, c->watchdog_timer); c->watchdog_timer = NULL; }

    etcp_router_conn_close(c);
    TEARDOWN();
    PASS();
    return 0;
}

static int test_loopback(void) {
    TEST("loopback — etcp_route_send to self");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();

    rx_reset(0x66);
    uint8_t buf[4] = { TEST_SVC_ID, 0x66, 0x00, 0x00 };
    struct ll_entry* e = queue_entry_new(0);
    if (!e) FAIL("queue_entry_new");
    e->dgram = u_malloc(4);
    if (!e->dgram) { queue_entry_free(e); FAIL("u_malloc"); }
    memcpy(e->dgram, buf, 4);
    e->len = 4;

    if (etcp_route_send(&inst, TOPO_GROUP_UTUN, inst.node_id, e, 0, 0) != 0) FAIL("loopback send failed");
    if (rx.delivered != 1) FAIL("loopback not delivered");
    if (rx.errors   != 0) FAIL("loopback data mismatch");

    TEARDOWN();
    PASS();
    return 0;
}

static int test_timestamp(void) {
    TEST("last_dgram_ts updated on data");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    struct ETCP_ROUTER_CONN* c = etcp_router_conn_get(&inst, TOPO_GROUP_UTUN, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c) FAIL("conn_get failed");

    uint16_t before = c->last_dgram_ts;

    rx_reset(0x99);
    uint8_t data[] = { TEST_SVC_ID, 0x99, 0 };
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, data + 1, 2, 0, ROUTER_FLAG_START);

    if (c->last_dgram_ts == 0) FAIL("last_dgram_ts zero after data");
    // Cancel ack_timer
    if (c->ack_timer) { uasync_cancel_timeout(ua, c->ack_timer); c->ack_timer = NULL; }

    etcp_router_conn_close(c);
    TEARDOWN();
    PASS();
    return 0;
}

static int test_conn_send_no_bgp(void) {
    TEST("conn_send — no BGP buffers with no_route (lossless)");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    struct ETCP_ROUTER_CONN* c = etcp_router_conn_get(&inst, TOPO_GROUP_UTUN, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c) FAIL("conn_get failed");

    uint8_t data[4] = { 1, 2, 3, 4 };
    int ret = etcp_router_conn_send(c, data, sizeof(data), 0);
    if (ret != 0) FAIL("conn_send should buffer (return 0) without BGP");
    if (c->no_route == 0) FAIL("no_route not set");
    if (queue_entry_count(c->send_q) != 1) FAIL("send_q count != 1");

    etcp_router_conn_close(c);
    TEARDOWN();
    PASS();
    return 0;
}

// ======================== Helper: pump random data ========================
static int pump_data(etcp_recv_fn recv_cb, struct UTUN_INSTANCE* inst,
                     uint8_t marker, int count, uint8_t flags) {
    uint8_t data[] = { TEST_SVC_ID, marker, 0 };
    for (int i = 0; i < count; i++) {
        uint8_t f = (i == 0) ? (flags | ROUTER_FLAG_START) : flags;
        inject(recv_cb, inst, TEST_REMOTE_NODE, TEST_SVC_ID, i, data + 1, 2, 0, f);
    }
    return count;
}

// ======================== Restart/session tests ========================

static int test_rst_flag(void) {
    TEST("RST flag — send-side restart, no service notify");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    g_notify_count = 0;

    int n = rand() % 10 + 1;
    rx_reset(0xA1);
    pump_data(recv_cb, &inst, 0xA1, n, 0);
    if (rx.delivered != n) FAIL("initial pump failed");

    g_notify_count = 0;
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, NULL, 0, 1, ROUTER_FLAG_RST);
    if (g_notify_count != 0) FAIL("RST should NOT notify service");

    struct ETCP_ROUTER_CONN* c = etcp_router_conn_get(&inst, TOPO_GROUP_UTUN, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c) FAIL("rconn should still exist after reset");
    if (c->tx_seq != 0 || c->start_sent != 0) FAIL("send side not reset by RST");
    if (c->rx_seq != (uint32_t)n) FAIL("rx side should be untouched by RST");
    if (!c->send_restart_pending) FAIL("send_restart_pending not set by RST");
    etcp_router_conn_close(c);

    TEARDOWN();
    PASS();
    return 0;
}

static int test_start_retransmit_no_restart(void) {
    TEST("START retransmit (same payload) — no restart");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    g_notify_count = 0;

    int n = rand() % 10 + 1;
    rx_reset(0xC1);
    pump_data(recv_cb, &inst, 0xC1, n, 0);
    if (rx.delivered != n) FAIL("initial pump failed");

    g_notify_count = 0;
    // ретрансмит первого пакета (seq=0, START, тот же payload) — не должен рестартовать
    uint8_t data[] = { TEST_SVC_ID, 0xC1, 0 };
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, data + 1, 2, 0, ROUTER_FLAG_START);
    if (g_notify_count != 0) FAIL("START retransmit should NOT restart");
    if (rx.delivered != n) FAIL("duplicate START should not deliver");

    TEARDOWN();
    PASS();
    return 0;
}

static int test_client_restart(void) {
    TEST("client restart — START flag detected after random data");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    g_notify_count = 0;

    int n = rand() % 10 + 1;
    rx_reset(0xB1);
    pump_data(recv_cb, &inst, 0xB1, n, 0);
    if (rx.delivered != n) FAIL("initial pump failed");

    rx_reset(0xB2);
    uint8_t data[] = { TEST_SVC_ID, 0xB2, 0 };
    inject(recv_cb, &inst, TEST_REMOTE_NODE, TEST_SVC_ID, 0, data + 1, 2, 0, ROUTER_FLAG_START);
    if (g_notify_count != 1) FAIL("restart not notified");
    if (rx.delivered < 1) FAIL("data after restart not delivered");

    TEARDOWN();
    PASS();
    return 0;
}

static int test_sess_id_increment(void) {
    TEST("sess_id — 0 on create, increments on restart");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();

    struct ETCP_ROUTER_CONN* c = etcp_router_conn_get(&inst, TOPO_GROUP_UTUN, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c) FAIL("rconn not found");
    if (c->sess_id != 0) FAIL("sess_id != 0 on fresh conn");

    etcp_router_conn_restart(&inst, TOPO_GROUP_UTUN, TEST_REMOTE_NODE, TEST_SVC_ID);
    c = etcp_router_conn_get(&inst, TOPO_GROUP_UTUN, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c) FAIL("rconn not found after first restart");
    if (c->sess_id != 1) FAIL("sess_id != 1 after first restart");

    etcp_router_conn_restart(&inst, TOPO_GROUP_UTUN, TEST_REMOTE_NODE, TEST_SVC_ID);
    c = etcp_router_conn_get(&inst, TOPO_GROUP_UTUN, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (c->sess_id != 2) FAIL("sess_id != 2 after second restart");

    etcp_router_conn_close(c);
    TEARDOWN();
    PASS();
    return 0;
}

static int test_server_reinit(void) {
    TEST("server reinit — new rconn gets start_sent=0 sess_id=0");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();

    int n = rand() % 10 + 1;
    pump_data(recv_cb, &inst, 0xE1, n, 0);

    etcp_router_destroy(&inst);
    memset(&inst.api_bindings, 0, sizeof(inst.api_bindings));
    memset(&inst.router_bindings, 0, sizeof(inst.router_bindings));
    if (etcp_router_init(&inst) != 0) FAIL("reinit failed");
    etcp_router_bind(&inst, TEST_SVC_ID, test_handler);
    recv_cb = inst.api_bindings.callbacks[ETCP_RT_ID_SVC_ROUTE];
    if (!recv_cb) FAIL("recv_cb not bound");

    struct ETCP_ROUTER_CONN* c = etcp_router_conn_get(&inst, TOPO_GROUP_UTUN, TEST_REMOTE_NODE, TEST_SVC_ID);
    if (!c) FAIL("rconn after reinit");
    if (c->start_sent != 0) FAIL("start_sent != 0 after reinit");
    if (c->sess_id != 0) FAIL("sess_id != 0 after reinit");

    etcp_router_conn_close(c);
    TEARDOWN();
    PASS();
    return 0;
}

// ======================== Signed message tests ========================

static int test_sign_verify_ok(void) {
    TEST("signed packet — verify OK, delivered to handler");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    setup_bgp_for_sign_test(&inst, 1);

    rx_reset(0xF1);
    uint8_t data[] = { TEST_SVC_ID, 0xF1, 0 };
    inject_signed(recv_cb, &inst, SIGNER_NODE, TEST_SVC_ID, 0, data + 1, 2, 0, 0);

    if (rx.delivered != 1) FAIL("signed packet not delivered");
    if (rx.errors   != 0) FAIL("data mismatch on signed packet");

    teardown_bgp_for_sign_test(&inst);
    TEARDOWN();
    PASS();
    return 0;
}

static int test_sign_bad_signature(void) {
    TEST("signed packet — tampered signature → dropped");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    setup_bgp_for_sign_test(&inst, 1);

    rx_reset(0xF2);
    uint8_t data[] = { TEST_SVC_ID, 0xF2, 0 };
    inject_signed(recv_cb, &inst, SIGNER_NODE, TEST_SVC_ID, 0, data + 1, 2, 0, 1 /*tamper*/);

    if (rx.delivered != 0) FAIL("tampered signed packet should be dropped");
    if (rx.errors   != 0) FAIL("handler should not be called for bad signature");

    teardown_bgp_for_sign_test(&inst);
    TEARDOWN();
    PASS();
    return 0;
}

static int test_sign_unknown_node(void) {
    TEST("signed packet — sender not in routing table → dropped");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    setup_bgp_for_sign_test(&inst, 1);

    rx_reset(0xF3);
    uint8_t data[] = { TEST_SVC_ID, 0xF3, 0 };
    uint64_t unknown = 0xDEAD000000000001ULL;
    inject_signed(recv_cb, &inst, unknown, TEST_SVC_ID, 0, data + 1, 2, 0, 0);

    if (rx.delivered != 0) FAIL("packet from unknown node should be dropped");
    if (rx.errors   != 0) FAIL("handler not called for unknown node");

    teardown_bgp_for_sign_test(&inst);
    TEARDOWN();
    PASS();
    return 0;
}

static int test_sign_no_ed25519_key(void) {
    TEST("signed packet — node in table but no Ed25519 key → dropped");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    setup_bgp_for_sign_test(&inst, 0 /*zero ed25519 key*/);

    rx_reset(0xF4);
    uint8_t data[] = { TEST_SVC_ID, 0xF4, 0 };
    inject_signed(recv_cb, &inst, SIGNER_NODE, TEST_SVC_ID, 0, data + 1, 2, 0, 0);

    if (rx.delivered != 0) FAIL("packet with zero ed25519 key should be dropped");

    teardown_bgp_for_sign_test(&inst);
    TEARDOWN();
    PASS();
    return 0;
}

static int test_sign_too_short(void) {
    TEST("signed packet — SIGNED flag but no signature bytes → dropped");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    setup_bgp_for_sign_test(&inst, 1);

    rx_reset(0xF5);
    struct SVC_ROUTE_HDR hdr;
    memset(&hdr, 0, sizeof(hdr));
    hdr.cmd         = ETCP_RT_ID_SVC_ROUTE;
    hdr.group_id    = TOPO_GROUP_UTUN;
    hdr.dst_node_id = inst.node_id;
    hdr.src_node_id = SIGNER_NODE;
    hdr.seq         = 0;
    hdr.svc_id      = TEST_SVC_ID;
    hdr.flags       = ROUTER_FLAG_SIGNED;
    uint8_t payload[] = { TEST_SVC_ID, 0xF5, 0 };
    size_t total = SVC_ROUTE_HDR_SIZE + sizeof(payload);
    struct ll_entry* e = queue_entry_new(0);
    if (!e) FAIL("queue_entry_new");
    e->dgram = u_malloc(total);
    if (!e->dgram) { queue_entry_free(e); FAIL("u_malloc"); }
    memcpy(e->dgram, &hdr, SVC_ROUTE_HDR_SIZE);
    memcpy(e->dgram + SVC_ROUTE_HDR_SIZE, payload, sizeof(payload));
    e->len = total;
    recv_cb(&fake_conn, e);

    if (rx.delivered != 0) FAIL("too-short signed packet should be dropped");

    teardown_bgp_for_sign_test(&inst);
    TEARDOWN();
    PASS();
    return 0;
}

// ======================== E2E encryption tests ========================
static int              g_e2e_ready = 0;
static struct SC_MYKEYS g_e2e_my_keys;
static struct SC_MYKEYS g_e2e_peer_keys;
static sc_context_t     g_e2e_tx_ctx;    // для шифрования тестовых данных (как отправитель)
static const uint64_t   E2E_PEER_NODE = TEST_E2E_PEER;

static int setup_e2e_keys(void) {
    if (g_e2e_ready) return 0;
    if (sc_generate_keypair(&g_e2e_my_keys) != SC_OK) return -1;
    if (sc_generate_keypair(&g_e2e_peer_keys) != SC_OK) return -1;
    sc_init_ctx(&g_e2e_tx_ctx, &g_e2e_my_keys);
    if (sc_set_peer_public_key(&g_e2e_tx_ctx, g_e2e_peer_keys.public_key, SC_PEER_PUBKEY_BIN) != SC_OK) return -1;
    g_e2e_ready = 1;
    return 0;
}

static void setup_bgp_for_e2e_test(struct UTUN_INSTANCE* inst, int register_peer) {
    inst->topo_groups = u_calloc(1, sizeof(struct TOPO_GROUPS));
    if (!inst->topo_groups) return;
    inst->topo_groups->instance = inst;
    inst->topo_groups->group_list = queue_new(inst->ua, 16, 0, 8, "group_list_e2e");
    inst->topo_groups->node_registry = queue_new(inst->ua, BGP_NODES_HASH_SIZE, 0, 8, "node_registry_e2e");

    if (register_peer) {
        struct TOPO_NODE* ni = u_calloc(1, sizeof(struct TOPO_NODE));
        if (!ni) return;
        ni->group_ref_count = 1; ni->node_id = E2E_PEER_NODE;
        memcpy(ni->public_key, g_e2e_peer_keys.public_key, SC_PUBKEY_SIZE);
        topo_node_registry_store(inst->topo_groups, ni);
    }

    struct ll_entry* qe = queue_entry_new(sizeof(struct TOPO_GROUP));
    if (!qe) return;
    struct TOPO_GROUP* group = (struct TOPO_GROUP*)qe;
    memset((uint8_t*)group + sizeof(struct ll_entry), 0, sizeof(*group) - sizeof(struct ll_entry));
    group->instance = inst;
    group->group_id = TOPO_GROUP_UTUN;
    queue_data_put_with_index(inst->topo_groups->group_list, &group->ll);
}

static void teardown_bgp_for_e2e_test(struct UTUN_INSTANCE* inst) {
    if (!inst || !inst->topo_groups) return;
    if (inst->topo_groups->node_registry) {
        struct ll_entry* e;
        while ((e = queue_data_get(inst->topo_groups->node_registry)) != NULL) queue_entry_free(e);
        queue_free(inst->topo_groups->node_registry);
        inst->topo_groups->node_registry = NULL;
    }
    if (inst->topo_groups->group_list) {
        struct ll_entry* ge;
        while ((ge = queue_data_get(inst->topo_groups->group_list)) != NULL) queue_entry_free(ge);
        queue_free(inst->topo_groups->group_list);
    }
    u_free(inst->topo_groups);
    inst->topo_groups = NULL;
}

static void inject_encrypted(struct UTUN_INSTANCE* inst, etcp_recv_fn recv_cb,
                              uint64_t src, uint8_t svc_id, uint32_t seq,
                              const uint8_t* pt, size_t pt_len, uint8_t extra_flags) {
    if (seq == 0) extra_flags |= ROUTER_FLAG_START;
    size_t enc_cap = pt_len + SC_NONCE_SIZE + SC_CRC32_SIZE + SC_TAG_SIZE;
    uint8_t* enc_buf = u_malloc(enc_cap);
    if (!enc_buf) { printf("  inject_enc: u_malloc enc_buf fail\n"); return; }
    size_t enc_len = 0;
    if (sc_encrypt(&g_e2e_tx_ctx, pt, pt_len, enc_buf, &enc_len) != SC_OK) {
        u_free(enc_buf); printf("  inject_enc: sc_encrypt fail\n"); return;
    }
    struct SVC_ROUTE_HDR hdr;
    memset(&hdr, 0, sizeof(hdr));
    hdr.cmd         = ETCP_RT_ID_SVC_ROUTE;
    hdr.group_id    = TOPO_GROUP_UTUN;
    hdr.dst_node_id = inst->node_id;
    hdr.src_node_id = src;
    hdr.seq         = seq;
    hdr.svc_id      = svc_id;
    hdr.flags       = ROUTER_FLAG_ENCRYPTED | extra_flags;

    size_t total = SVC_ROUTE_HDR_SIZE + enc_len;
    struct ll_entry* e = queue_entry_new(0);
    if (!e) { u_free(enc_buf); return; }
    e->dgram = u_malloc(total);
    if (!e->dgram) { queue_entry_free(e); u_free(enc_buf); return; }
    memcpy(e->dgram, &hdr, SVC_ROUTE_HDR_SIZE);
    memcpy(e->dgram + SVC_ROUTE_HDR_SIZE, enc_buf, enc_len);
    e->len = total;
    u_free(enc_buf);
    recv_cb(&fake_conn, e);
}

static int test_e2e_decrypt_basic(void) {
    TEST("E2E decrypt — basic round-trip");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    setup_bgp_for_e2e_test(&inst, 1);
    memcpy(&inst.my_keys, &g_e2e_my_keys, sizeof(g_e2e_my_keys));

    rx_reset(0xE1);
    uint8_t pt[] = { TEST_SVC_ID, 0xE1, 0xAA };
    inject_encrypted(&inst, recv_cb, E2E_PEER_NODE, TEST_SVC_ID, 0, pt + 1, 2, 0);
    if (rx.delivered != 1 || rx.errors != 0) FAIL("decrypt basic");

    teardown_bgp_for_e2e_test(&inst);
    TEARDOWN();
    PASS();
    return 0;
}

static int test_e2e_decrypt_no_nodeinfo(void) {
    TEST("E2E decrypt — no NODEINFO → dropped");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    setup_bgp_for_e2e_test(&inst, 0);
    memcpy(&inst.my_keys, &g_e2e_my_keys, sizeof(g_e2e_my_keys));

    rx_reset(0xE2);
    uint8_t pt[] = { TEST_SVC_ID, 0xE2, 0xBB };
    inject_encrypted(&inst, recv_cb, E2E_PEER_NODE, TEST_SVC_ID, 0, pt + 1, 2, 0);
    if (rx.delivered != 0) FAIL("should drop without NODEINFO");

    teardown_bgp_for_e2e_test(&inst);
    TEARDOWN();
    PASS();
    return 0;
}

static int test_e2e_decrypt_tampered(void) {
    TEST("E2E decrypt — tampered ciphertext → dropped");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    setup_bgp_for_e2e_test(&inst, 1);
    memcpy(&inst.my_keys, &g_e2e_my_keys, sizeof(g_e2e_my_keys));

    rx_reset(0xE3);
    uint8_t pt[] = { TEST_SVC_ID, 0xE3, 0xCC };
    size_t enc_cap = sizeof(pt) + SC_NONCE_SIZE + SC_CRC32_SIZE + SC_TAG_SIZE;
    uint8_t* enc_buf = u_malloc(enc_cap);
    if (!enc_buf) FAIL("alloc");
    size_t enc_len = 0;
    if (sc_encrypt(&g_e2e_tx_ctx, pt + 1, 2, enc_buf, &enc_len) != SC_OK) { u_free(enc_buf); FAIL("encrypt"); }
    enc_buf[SC_NONCE_SIZE + 1] ^= 0xFF; // tamper

    struct SVC_ROUTE_HDR hdr;
    memset(&hdr, 0, sizeof(hdr));
    hdr.cmd = ETCP_RT_ID_SVC_ROUTE; hdr.group_id = TOPO_GROUP_UTUN;
    hdr.dst_node_id = inst.node_id; hdr.src_node_id = E2E_PEER_NODE;
    hdr.seq = 0; hdr.svc_id = TEST_SVC_ID; hdr.flags = ROUTER_FLAG_ENCRYPTED;

    size_t total = SVC_ROUTE_HDR_SIZE + enc_len;
    struct ll_entry* e = queue_entry_new(0);
    if (!e) { u_free(enc_buf); FAIL("entry"); }
    e->dgram = u_malloc(total);
    if (!e->dgram) { queue_entry_free(e); u_free(enc_buf); FAIL("dgram"); }
    memcpy(e->dgram, &hdr, SVC_ROUTE_HDR_SIZE);
    memcpy(e->dgram + SVC_ROUTE_HDR_SIZE, enc_buf, enc_len);
    e->len = total;
    u_free(enc_buf);
    recv_cb(&fake_conn, e);

    if (rx.delivered != 0) FAIL("tampered should be dropped");

    teardown_bgp_for_e2e_test(&inst);
    TEARDOWN();
    PASS();
    return 0;
}

static int test_e2e_cache_reuse(void) {
    TEST("E2E cache — second call returns same ctx");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    setup_bgp_for_e2e_test(&inst, 1);
    memcpy(&inst.my_keys, &g_e2e_my_keys, sizeof(g_e2e_my_keys));

    rx_reset(0xE4);
    uint8_t pt[] = { TEST_SVC_ID, 0xE4, 0xDD };
    inject_encrypted(&inst, recv_cb, E2E_PEER_NODE, TEST_SVC_ID, 0, pt + 1, 2, 0);
    if (rx.delivered != 1) FAIL("first");

    int slot = -1;
    for (int i = 0; i < E2E_CTX_CACHE_SIZE; i++)
        if (inst.e2e_ctx_cache[i].valid && inst.e2e_ctx_cache[i].peer_node_id == E2E_PEER_NODE) { slot = i; break; }
    if (slot < 0) FAIL("cache miss after first decrypt");

    uint8_t* prev_seskey = inst.e2e_ctx_cache[slot].ctx.session_key;

    rx_reset(0xE5);
    uint8_t pt2[] = { TEST_SVC_ID, 0xE5, 0xEE };
    inject_encrypted(&inst, recv_cb, E2E_PEER_NODE, TEST_SVC_ID, 1, pt2 + 1, 2, 0);
    if (rx.delivered != 1) FAIL("second");
    if (inst.e2e_ctx_cache[slot].ctx.session_key != prev_seskey) FAIL("ctx recreated");

    teardown_bgp_for_e2e_test(&inst);
    TEARDOWN();
    PASS();
    return 0;
}

static int test_e2e_combined_signed(void) {
    TEST("E2E ENCRYPTED+SIGNED — verify+decrypt+deliver");
    struct UASYNC* ua; struct UTUN_INSTANCE inst; etcp_recv_fn recv_cb;
    SETUP();
    setup_bgp_for_sign_test(&inst, 1);
    memcpy(&inst.my_keys, &g_sign_keys, sizeof(g_sign_keys));

    struct SC_MYKEYS peer_keys;
    if (sc_generate_keypair(&peer_keys) != SC_OK) FAIL("peer keygen");

    // Set SIGNER_NODE's X25519 pubkey in NODEINFO for E2E ECDH
    struct TOPO_NODE* sign_ni = topo_node_registry_find(inst.topo_groups, SIGNER_NODE);
    if (!sign_ni) FAIL("SIGNER_NODE not in registry");
    memcpy(sign_ni->public_key, peer_keys.public_key, SC_PUBKEY_SIZE);

    // E2E tx ctx for encrypting test data (same ECDH as receiver will do)
    sc_context_t tx_ctx;
    sc_init_ctx(&tx_ctx, &inst.my_keys);
    if (sc_set_peer_public_key(&tx_ctx, peer_keys.public_key, SC_PEER_PUBKEY_BIN) != SC_OK) FAIL("tx ECDH");

    rx_reset(0xE6);
    uint8_t pt[] = { TEST_SVC_ID, 0xE6, 0xFF };

    size_t enc_cap = 3 + SC_NONCE_SIZE + SC_CRC32_SIZE + SC_TAG_SIZE;
    uint8_t* enc_buf = u_malloc(enc_cap);
    size_t enc_len = 0;
    if (sc_encrypt(&tx_ctx, pt + 1, 2, enc_buf, &enc_len) != SC_OK) { u_free(enc_buf); FAIL("encrypt"); }

    size_t hdr_pl = SVC_ROUTE_HDR_SIZE + enc_len;
    size_t total  = hdr_pl + SC_SIGN_SIZE;
    uint8_t* dgram = u_malloc(total);
    struct SVC_ROUTE_HDR* hdr = (struct SVC_ROUTE_HDR*)dgram;
    memset(hdr, 0, SVC_ROUTE_HDR_SIZE);
    hdr->cmd = ETCP_RT_ID_SVC_ROUTE; hdr->group_id = TOPO_GROUP_UTUN;
    hdr->dst_node_id = inst.node_id; hdr->src_node_id = SIGNER_NODE;
    hdr->seq = 0; hdr->svc_id = TEST_SVC_ID;
    hdr->flags = ROUTER_FLAG_ENCRYPTED | ROUTER_FLAG_SIGNED | ROUTER_FLAG_START;
    memcpy(dgram + SVC_ROUTE_HDR_SIZE, enc_buf, enc_len);

    if (sc_ed25519_sign(g_sign_ed25519_privkey, dgram, hdr_pl, dgram + hdr_pl) != SC_OK) { u_free(dgram); u_free(enc_buf); FAIL("sign"); }

    struct ll_entry* e = queue_entry_new(0);
    if (!e) { u_free(dgram); u_free(enc_buf); FAIL("entry"); }
    e->dgram = dgram; e->len = total; u_free(enc_buf);
    recv_cb(&fake_conn, e);

    if (rx.delivered != 1 || rx.errors != 0) FAIL("combined signed+encrypted");

    teardown_bgp_for_sign_test(&inst);
    TEARDOWN();
    PASS();
    return 0;
}

// ======================== Main ========================
int main(void) {
    // Run all tests
    test_init_destroy();
    test_bind_unbind();
    test_conn_get_create();
    test_conn_get_reuse();
    test_conn_close();
    test_in_order();
    test_out_of_order();
    test_duplicate_same();
    test_duplicate_past();
    test_out_of_bounds();
    test_circular_wrap();
    test_data_integrity();
    test_ack_receive();
    test_ack_timer();
    test_send_q();
    test_loopback();
    test_timestamp();
    test_conn_send_no_bgp();
    test_rst_flag();
    test_start_retransmit_no_restart();
    test_client_restart();
    test_sess_id_increment();
    test_server_reinit();

    if (setup_sign_keys() != 0) { printf("  SKIP signed tests — crypto init failed\n"); }
    else {
        test_sign_verify_ok();
        test_sign_bad_signature();
        test_sign_unknown_node();
        test_sign_no_ed25519_key();
        test_sign_too_short();
    }

    if (setup_e2e_keys() != 0) { printf("  SKIP E2E tests — crypto init failed\n"); }
    else {
        test_e2e_decrypt_basic();
        test_e2e_decrypt_no_nodeinfo();
        test_e2e_decrypt_tampered();
        test_e2e_cache_reuse();
        test_e2e_combined_signed();
    }

    printf("\n=== Results: %d/%d passed, %d failed ===\n", test_passed, test_total, test_failed);
    return test_failed > 0 ? 1 : 0;
}