djhackersdev_bemanitools/src/main/iidxhook-util/eamuse.c

#define LOG_MODULE "eamuse-hook"

#include <windows.h>
#include <winsock2.h>
#include <ws2tcpip.h>

#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>

#include "hook/table.h"

#include "iidxhook-util/eamuse.h"

#include "util/defs.h"
#include "util/log.h"
#include "util/str.h"

/* ------------------------------------------------------------------------- */

static int STDCALL
my_connect(SOCKET s, const struct sockaddr *addr, int addrlen);
static struct hostent FAR *STDCALL my_gethostbyname(const char *nameB);

static int(STDCALL *real_connect)(
    SOCKET s, const struct sockaddr *addr, int addrlen);
static struct hostent FAR *(STDCALL *real_gethostbyname)(const char *nameB);
/* ------------------------------------------------------------------------- */

static const struct hook_symbol eamuse_hook_syms[] = {
    /*  WS2_32.DLL's SDK import lib generates ordinal imports, so these
       ordinals are a frozen aspect of the Win32 ABI. */

    {.name = "connect",
     .ordinal = 4,
     .patch = my_connect,
     .link = (void **) &real_connect},
    {.name = "gethostbyname",
     .ordinal = 52,
     .patch = my_gethostbyname,
     .link = (void **) &real_gethostbyname},
};

/* ------------------------------------------------------------------------- */

static struct net_addr eamuse_server_addr;
static struct net_addr eamuse_server_addr_resolved;

/* ------------------------------------------------------------------------- */

static int STDCALL
my_connect(SOCKET s, const struct sockaddr *addr, int addrlen)
{
    char *tmp;

    if (addr->sa_family == AF_INET) {
        /* check if we got our server's address */
        struct sockaddr_in *addr_in = (struct sockaddr_in *) addr;

        if (addr_in->sin_addr.S_un.S_addr ==
            eamuse_server_addr_resolved.ipv4.addr) {
            tmp = net_addr_to_str(&eamuse_server_addr_resolved);
            log_misc(
                "Patching port '%d' of %s to %d",
                ntohs(addr_in->sin_port),
                tmp,
                eamuse_server_addr_resolved.ipv4.port);
            free(tmp);

            addr_in->sin_port = htons(eamuse_server_addr_resolved.ipv4.port);
        }
    }

    return real_connect(s, addr, addrlen);
}

static struct hostent FAR *STDCALL my_gethostbyname(const char *name)
{
    // IIDX 9-13 use the `services` domain (not `services.eamuse.konami.fun`).
    if (strcmp(name, "services") != 0) {
        return real_gethostbyname(name);
    }

    char *tmp;

    tmp = net_addr_to_str(&eamuse_server_addr_resolved);
    log_misc("my_gethostbyname: '%s' to ip %s", name, tmp);
    free(tmp);

    /* very ugly hack to get this working.
    don't bother with dynamic allocations and have stuff staticly alloc'd
    just populate what's touched by the game */
    static struct hostent ret;
    static uint32_t addr;
    static char *arr[2];
    static bool first = true;

    if (first) {
        ret.h_length = 4;
        ret.h_addr_list = (char **) &arr;
        ret.h_addr_list[0] = (char *) &addr;
        ret.h_addr_list[1] = NULL;
        ret.h_aliases = NULL;
        ret.h_name = NULL;
    }

    addr = eamuse_server_addr_resolved.ipv4.addr;

    return &ret;
}

/* ------------------------------------------------------------------------- */

void eamuse_hook_init(void)
{
    hook_table_apply(
        NULL, "ws2_32.dll", eamuse_hook_syms, lengthof(eamuse_hook_syms));

    log_info("Inserted eamuse hooks");
}

void eamuse_set_addr(const struct net_addr *addr)
{
    char *tmp_str;
    char *tmp_str2;

    log_assert(addr);

    memcpy(&eamuse_server_addr, addr, sizeof(struct net_addr));

    tmp_str = net_addr_to_str(&eamuse_server_addr);

    eamuse_server_addr_resolved.type = NET_ADDR_TYPE_IPV4;

    if (!net_resolve_hostname_net_addr(
            &eamuse_server_addr, &eamuse_server_addr_resolved.ipv4)) {
        log_fatal("Failed to resolve eamuse server address: %s", tmp_str);
        free(tmp_str);
        return;
    }

    tmp_str2 = net_addr_to_str(&eamuse_server_addr_resolved);

    // when resolving URLs with net_str_parse
    // it will default to NET_INVALID_PORT if no port is specified
    // assume default 80 here as a good sanity check
    if (eamuse_server_addr_resolved.ipv4.port == NET_INVALID_PORT) {
        log_info("No port was specified, using port 80 as fallback");
        eamuse_server_addr_resolved.ipv4.port = 80;
    }

    log_info("Target eamuse server %s resolved to %s", tmp_str, tmp_str2);

    free(tmp_str);
    free(tmp_str2);
}

void eamuse_check_connection()
{
    if (!net_check_remote_connection(&eamuse_server_addr_resolved, 5000)) {
        log_info("Target eamuse server reachable.");
    } else {
        log_warning(
            "Target eamuse server is not reachable. Game might throw "
            "network errors/warnings if eamuse is enabled.");
    }
}