Line data    Source code

       1              : /* SPDX-License-Identifier: GPL-3.0-or-later */
       2              : /* Copyright 2026 Peter Csaszar */
       3              : 
       4              : /**
       5              :  * @file app/dc_config.c
       6              :  * @brief Hardcoded fallback DC endpoint table with runtime overrides (FEAT-38).
       7              :  */
       8              : 
       9              : #include "app/dc_config.h"
      10              : 
      11              : #include <stddef.h>
      12              : #include <stdlib.h>
      13              : #include <string.h>
      14              : 
      15              : static const DcEndpoint ENDPOINTS[] = {
      16              :     { 1, "149.154.175.50",  443 },
      17              :     { 2, "149.154.167.50",  443 },
      18              :     { 3, "149.154.175.100", 443 },
      19              :     { 4, "149.154.167.91",  443 },
      20              :     { 5, "91.108.56.130",   443 },
      21              : };
      22              : 
      23              : #define ENDPOINT_COUNT (sizeof(ENDPOINTS) / sizeof(ENDPOINTS[0]))
      24              : #define DC_ID_MAX 5
      25              : 
      26              : /**
      27              :  * @brief Per-process redirect used by tests.
      28              :  *
      29              :  * When TG_CLI_DC_HOST and TG_CLI_DC_PORT are set in the environment every
      30              :  * dc_lookup() call returns a synthetic endpoint pointing at those
      31              :  * coordinates.  This lets the PTY-based functional tests redirect the
      32              :  * production binary to a local stub server without modifying the binary or
      33              :  * the DC table.
      34              :  */
      35              : static DcEndpoint g_env_override;
      36              : 
      37              : /**
      38              :  * FEAT-38: Per-DC host overrides from config.ini.
      39              :  * Index 0 = DC1 … index 4 = DC5.  NULL means use the compiled-in default.
      40              :  */
      41              : static char *g_host_overrides[DC_ID_MAX]; /* heap-allocated or NULL */
      42              : static DcEndpoint g_config_override;      /* scratch space for the returned value */
      43              : 
      44           62 : void dc_config_set_host_override(int dc_id, const char *host) {
      45           62 :     if (dc_id < 1 || dc_id > DC_ID_MAX) return;
      46           62 :     int idx = dc_id - 1;
      47              : 
      48           62 :     free(g_host_overrides[idx]);
      49           62 :     g_host_overrides[idx] = NULL;
      50              : 
      51           62 :     if (host && *host) {
      52            2 :         g_host_overrides[idx] = strdup(host);
      53              :     }
      54              : }
      55              : 
      56           58 : const DcEndpoint *dc_lookup(int dc_id) {
      57              :     /* Negative dc_id is used for Telegram test DCs: dc=-N maps to the same
      58              :      * endpoint as dc=N for connection purposes.  The caller keeps the signed
      59              :      * value to embed it in p_q_inner_data_dc.
      60              :      * dc=0 is a wildcard accepted by Telegram test servers — connect to
      61              :      * DEFAULT_DC_ID's endpoint so the transport works. */
      62           58 :     int abs_id = (dc_id == 0) ? DEFAULT_DC_ID
      63           58 :                : (dc_id < 0)  ? -dc_id
      64              :                :                 dc_id;
      65              : 
      66              :     /* Environment redirect takes highest priority (used by integration tests). */
      67           58 :     const char *env_host = getenv("TG_CLI_DC_HOST");
      68           58 :     const char *env_port = getenv("TG_CLI_DC_PORT");
      69           58 :     if (env_host && *env_host && env_port && *env_port) {
      70            0 :         g_env_override.id   = dc_id;
      71            0 :         g_env_override.host = env_host;
      72            0 :         g_env_override.port = atoi(env_port);
      73            0 :         return &g_env_override;
      74              :     }
      75              : 
      76              :     /* config.ini override (FEAT-38) — applies only if the absolute DC id is valid. */
      77           58 :     if (abs_id >= 1 && abs_id <= DC_ID_MAX && g_host_overrides[abs_id - 1]) {
      78              :         /* Find the built-in entry to inherit the port. */
      79            4 :         for (size_t i = 0; i < ENDPOINT_COUNT; i++) {
      80            4 :             if (ENDPOINTS[i].id == abs_id) {
      81            2 :                 g_config_override.id   = dc_id;
      82            2 :                 g_config_override.host = g_host_overrides[abs_id - 1];
      83            2 :                 g_config_override.port = ENDPOINTS[i].port;
      84            2 :                 return &g_config_override;
      85              :             }
      86              :         }
      87              :     }
      88              : 
      89              :     /* Fall back to compiled-in table (match on absolute id). */
      90          192 :     for (size_t i = 0; i < ENDPOINT_COUNT; i++) {
      91          187 :         if (ENDPOINTS[i].id == abs_id) {
      92           51 :             g_config_override.id   = dc_id;
      93           51 :             g_config_override.host = ENDPOINTS[i].host;
      94           51 :             g_config_override.port = ENDPOINTS[i].port;
      95           51 :             return &g_config_override;
      96              :         }
      97              :     }
      98            5 :     return NULL;
      99              : }