/*=========================================================================*\
* TCP object 
* LuaSocket toolkit
*
* RCS ID: $Id: tcp.c,v 1.42 2009/05/27 09:31:35 diego Exp $
\*=========================================================================*/
#include <string.h> 

#include "lua.h"
#include "lauxlib.h"

#include "auxiliar.h"
#include "socket.h"
#include "inet.h"
#include "options.h"
#include "tcp.h"

/*=========================================================================*\
* Internal function prototypes
\*=========================================================================*/
static int global_create(lua_State *L);
static int global_connect6(lua_State *L);
static int global_bind6(lua_State *L);
static int meth_connect(lua_State *L);
static int meth_listen(lua_State *L);
static int meth_bind(lua_State *L);
static int meth_send(lua_State *L);
static int meth_getstats(lua_State *L);
static int meth_setstats(lua_State *L);
static int meth_getsockname(lua_State *L);
static int meth_getpeername(lua_State *L);
static int meth_shutdown(lua_State *L);
static int meth_receive(lua_State *L);
static int meth_accept(lua_State *L);
static int meth_close(lua_State *L);
static int meth_setoption(lua_State *L);
static int meth_settimeout(lua_State *L);
static int meth_getfd(lua_State *L);
static int meth_setfd(lua_State *L);
static int meth_dirty(lua_State *L);

/* tcp object methods */
static luaL_reg tcp_methods[] = {
    {"__gc",        meth_close},
    {"__tostring",  auxiliar_tostring},
    {"accept",      meth_accept},
    {"bind",        meth_bind},
    {"close",       meth_close},
    {"connect",     meth_connect},
    {"dirty",       meth_dirty},
    {"getfd",       meth_getfd},
    {"getpeername", meth_getpeername},
    {"getsockname", meth_getsockname},
    {"getstats",    meth_getstats},
    {"setstats",    meth_setstats},
    {"listen",      meth_listen},
    {"receive",     meth_receive},
    {"send",        meth_send},
    {"setfd",       meth_setfd},
    {"setoption",   meth_setoption},
    {"setpeername", meth_connect},
    {"setsockname", meth_bind},
    {"settimeout",  meth_settimeout},
    {"shutdown",    meth_shutdown},
    {NULL,          NULL}
};

/* socket option handlers */
static t_opt optset[] = {
    {"keepalive",   opt_set_keepalive},
    {"reuseaddr",   opt_set_reuseaddr},
    {"tcp-nodelay", opt_set_tcp_nodelay},
    {"linger",      opt_set_linger},
    {NULL,          NULL}
};

/* functions in library namespace */
static luaL_reg func[] = {
    {"tcp", global_create},
    {"connect6", global_connect6},
    {"bind6", global_bind6},
    {NULL, NULL}
};

/*-------------------------------------------------------------------------*\
* Initializes module
\*-------------------------------------------------------------------------*/
int tcp_open(lua_State *L)
{
    /* create classes */
    auxiliar_newclass(L, "tcp{master}", tcp_methods);
    auxiliar_newclass(L, "tcp{client}", tcp_methods);
    auxiliar_newclass(L, "tcp{server}", tcp_methods);
    /* create class groups */
    auxiliar_add2group(L, "tcp{master}", "tcp{any}");
    auxiliar_add2group(L, "tcp{client}", "tcp{any}");
    auxiliar_add2group(L, "tcp{server}", "tcp{any}");
    /* define library functions */
    luaL_openlib(L, NULL, func, 0); 
    return 0;
}

/*=========================================================================*\
* Lua methods
\*=========================================================================*/
/*-------------------------------------------------------------------------*\
* Just call buffered IO methods
\*-------------------------------------------------------------------------*/
static int meth_send(lua_State *L) {
    p_tcp tcp = (p_tcp) auxiliar_checkclass(L, "tcp{client}", 1);
    return buffer_meth_send(L, &tcp->buf);
}

static int meth_receive(lua_State *L) {
    p_tcp tcp = (p_tcp) auxiliar_checkclass(L, "tcp{client}", 1);
    return buffer_meth_receive(L, &tcp->buf);
}

static int meth_getstats(lua_State *L) {
    p_tcp tcp = (p_tcp) auxiliar_checkclass(L, "tcp{client}", 1);
    return buffer_meth_getstats(L, &tcp->buf);
}

static int meth_setstats(lua_State *L) {
    p_tcp tcp = (p_tcp) auxiliar_checkclass(L, "tcp{client}", 1);
    return buffer_meth_setstats(L, &tcp->buf);
}

/*-------------------------------------------------------------------------*\
* Just call option handler
\*-------------------------------------------------------------------------*/
static int meth_setoption(lua_State *L)
{
    p_tcp tcp = (p_tcp) auxiliar_checkgroup(L, "tcp{any}", 1);
    return opt_meth_setoption(L, optset, &tcp->sock);
}

/*-------------------------------------------------------------------------*\
* Select support methods
\*-------------------------------------------------------------------------*/
static int meth_getfd(lua_State *L)
{
    p_tcp tcp = (p_tcp) auxiliar_checkgroup(L, "tcp{any}", 1);
    lua_pushnumber(L, (int) tcp->sock);
    return 1;
}

/* this is very dangerous, but can be handy for those that are brave enough */
static int meth_setfd(lua_State *L)
{
    p_tcp tcp = (p_tcp) auxiliar_checkgroup(L, "tcp{any}", 1);
    tcp->sock = (t_socket) luaL_checknumber(L, 2); 
    return 0;
}

static int meth_dirty(lua_State *L)
{
    p_tcp tcp = (p_tcp) auxiliar_checkgroup(L, "tcp{any}", 1);
    lua_pushboolean(L, !buffer_isempty(&tcp->buf));
    return 1;
}

/*-------------------------------------------------------------------------*\
* Waits for and returns a client object attempting connection to the 
* server object 
\*-------------------------------------------------------------------------*/
static int meth_accept(lua_State *L)
{
    p_tcp server = (p_tcp) auxiliar_checkclass(L, "tcp{server}", 1);
    p_timeout tm = timeout_markstart(&server->tm);
    t_socket sock;
    int err = socket_accept(&server->sock, &sock, NULL, NULL, tm);
    /* if successful, push client socket */
    if (err == IO_DONE) {
        p_tcp clnt = (p_tcp) lua_newuserdata(L, sizeof(t_tcp));
        auxiliar_setclass(L, "tcp{client}", -1);
        /* initialize structure fields */
        socket_setnonblocking(&sock);
        clnt->sock = sock;
        io_init(&clnt->io, (p_send) socket_send, (p_recv) socket_recv, 
                (p_error) socket_ioerror, &clnt->sock);
        timeout_init(&clnt->tm, -1, -1);
        buffer_init(&clnt->buf, &clnt->io, &clnt->tm);
        return 1;
    } else {
        lua_pushnil(L); 
        lua_pushstring(L, socket_strerror(err));
        return 2;
    }
}

/*-------------------------------------------------------------------------*\
* Binds an object to an address 
\*-------------------------------------------------------------------------*/
static int meth_bind(lua_State *L)
{
    p_tcp tcp = (p_tcp) auxiliar_checkclass(L, "tcp{master}", 1);
    const char *address =  luaL_checkstring(L, 2);
    unsigned short port = (unsigned short) luaL_checknumber(L, 3);
    const char *err = inet_trybind(&tcp->sock, address, port);
    if (err) {
        lua_pushnil(L);
        lua_pushstring(L, err);
        return 2;
    }
    lua_pushnumber(L, 1);
    return 1;
}

/*-------------------------------------------------------------------------*\
* Turns a master tcp object into a client object.
\*-------------------------------------------------------------------------*/
static int meth_connect(lua_State *L)
{

    p_tcp tcp = (p_tcp) auxiliar_checkgroup(L, "tcp{any}", 1);
    const char *address =  luaL_checkstring(L, 2);
    unsigned short port = (unsigned short) luaL_checknumber(L, 3);
    p_timeout tm = timeout_markstart(&tcp->tm);
    const char *err = inet_tryconnect(&tcp->sock, address, port, tm);
    /* have to set the class even if it failed due to non-blocking connects */
    auxiliar_setclass(L, "tcp{client}", 1);
    if (err) {
        lua_pushnil(L);
        lua_pushstring(L, err);
        return 2;
    }
    lua_pushnumber(L, 1);
    return 1;
}

/*-------------------------------------------------------------------------*\
* Closes socket used by object 
\*-------------------------------------------------------------------------*/
static int meth_close(lua_State *L)
{
    p_tcp tcp = (p_tcp) auxiliar_checkgroup(L, "tcp{any}", 1);
    socket_destroy(&tcp->sock);
    lua_pushnumber(L, 1);
    return 1;
}

/*-------------------------------------------------------------------------*\
* Puts the sockt in listen mode
\*-------------------------------------------------------------------------*/
static int meth_listen(lua_State *L)
{
    p_tcp tcp = (p_tcp) auxiliar_checkclass(L, "tcp{master}", 1);
    int backlog = (int) luaL_optnumber(L, 2, 32);
    int err = socket_listen(&tcp->sock, backlog);
    if (err != IO_DONE) {
        lua_pushnil(L);
        lua_pushstring(L, socket_strerror(err));
        return 2;
    }
    /* turn master object into a server object */
    auxiliar_setclass(L, "tcp{server}", 1);
    lua_pushnumber(L, 1);
    return 1;
}

/*-------------------------------------------------------------------------*\
* Shuts the connection down partially
\*-------------------------------------------------------------------------*/
static int meth_shutdown(lua_State *L)
{
    p_tcp tcp = (p_tcp) auxiliar_checkclass(L, "tcp{client}", 1);
    const char *how = luaL_optstring(L, 2, "both");
    switch (how[0]) {
        case 'b':
            if (strcmp(how, "both")) goto error;
            socket_shutdown(&tcp->sock, 2);
            break;
        case 's':
            if (strcmp(how, "send")) goto error;
            socket_shutdown(&tcp->sock, 1);
            break;
        case 'r':
            if (strcmp(how, "receive")) goto error;
            socket_shutdown(&tcp->sock, 0);
            break;
    }
    lua_pushnumber(L, 1);
    return 1;
error:
    luaL_argerror(L, 2, "invalid shutdown method");
    return 0;
}

/*-------------------------------------------------------------------------*\
* Just call inet methods
\*-------------------------------------------------------------------------*/
static int meth_getpeername(lua_State *L)
{
    p_tcp tcp = (p_tcp) auxiliar_checkgroup(L, "tcp{any}", 1);
    return inet_meth_getpeername(L, &tcp->sock);
}

static int meth_getsockname(lua_State *L)
{
    p_tcp tcp = (p_tcp) auxiliar_checkgroup(L, "tcp{any}", 1);
    return inet_meth_getsockname(L, &tcp->sock);
}

/*-------------------------------------------------------------------------*\
* Just call tm methods
\*-------------------------------------------------------------------------*/
static int meth_settimeout(lua_State *L)
{
    p_tcp tcp = (p_tcp) auxiliar_checkgroup(L, "tcp{any}", 1);
    return timeout_meth_settimeout(L, &tcp->tm);
}

/*=========================================================================*\
* Library functions
\*=========================================================================*/
/*-------------------------------------------------------------------------*\
* Creates a master tcp object 
\*-------------------------------------------------------------------------*/
static int global_create(lua_State *L) {
    t_socket sock;
    const char *err = inet_trycreate(&sock, SOCK_STREAM);
    /* try to allocate a system socket */
    if (!err) { 
        /* allocate tcp object */
        p_tcp tcp = (p_tcp) lua_newuserdata(L, sizeof(t_tcp));
        /* set its type as master object */
        auxiliar_setclass(L, "tcp{master}", -1);
        /* initialize remaining structure fields */
        socket_setnonblocking(&sock);
        tcp->sock = sock;
        io_init(&tcp->io, (p_send) socket_send, (p_recv) socket_recv, 
                (p_error) socket_ioerror, &tcp->sock);
        timeout_init(&tcp->tm, -1, -1);
        buffer_init(&tcp->buf, &tcp->io, &tcp->tm);
        return 1;
    } else {
        lua_pushnil(L);
        lua_pushstring(L, err);
        return 2;
    }
}

static const char *trybind6(const char *localaddr, const char *localserv,
    struct addrinfo *bindhints, p_tcp tcp) {
    struct addrinfo *iterator = NULL, *resolved = NULL;
    const char *err = NULL;
    /* translate luasocket special values to C */
    if (strcmp(localaddr, "*") == 0) localaddr = NULL;
    if  (!localserv) localserv = "0";
    /* try resolving */
    err = socket_gaistrerror(getaddrinfo(localaddr, localserv, 
            bindhints, &resolved));
    if (err) {
        if (resolved) freeaddrinfo(resolved);
        return err;
    }
    /* iterate over resolved addresses until one is good */
    for (iterator = resolved; iterator; iterator = iterator->ai_next) {
        /* create a new socket each time because parameters
         * may have changed */
        err = socket_strerror(socket_create(&tcp->sock, 
            iterator->ai_family, iterator->ai_socktype, 
            iterator->ai_protocol));
        /* if failed to create socket, bail out */
        if (err != NULL) {
            freeaddrinfo(resolved);
            return err;
        }
        /* all sockets are set as non-blocking initially */
        socket_setnonblocking(&tcp->sock);
        /* try binding to local address */
        err = socket_strerror(socket_bind(&tcp->sock, 
            (SA *) iterator->ai_addr,
            iterator->ai_addrlen));
        /* if faiiled, we try the next one */
        if (err != NULL) socket_destroy(&tcp->sock);
        /* if success, we abort loop */
        else break;
    }
    /* at this point, if err is not set, se succeeded */
    if (err == NULL) {
        /* save family of chosen local address */ 
        bindhints->ai_family = iterator->ai_family;
    }
    /* cleanup and return error */
    freeaddrinfo(resolved);
    return err; 
}

static int global_bind6(lua_State *L) {
    const char *localaddr  = luaL_checkstring(L, 1);
    const char *localserv  = luaL_checkstring(L, 2);
    int backlog = luaL_checkint(L, 3);
    p_tcp tcp = (p_tcp) lua_newuserdata(L, sizeof(t_tcp));
    struct addrinfo bindhints;
    const char *err = NULL;
    /* initialize tcp structure */
    io_init(&tcp->io, (p_send) socket_send, (p_recv) socket_recv, 
            (p_error) socket_ioerror, &tcp->sock);
    timeout_init(&tcp->tm, -1, -1);
    buffer_init(&tcp->buf, &tcp->io, &tcp->tm);
    tcp->sock = SOCKET_INVALID;
    /* try binding to local address */
    memset(&bindhints, 0, sizeof(bindhints));
    bindhints.ai_socktype = SOCK_STREAM;
    bindhints.ai_family = PF_UNSPEC;
    bindhints.ai_flags = AI_PASSIVE;
    err = trybind6(localaddr, localserv, &bindhints, tcp);
    if (err == NULL) {
        /* all server sockets initially with reuseaddr set */
        int val = 1;
        setsockopt(tcp->sock, SOL_SOCKET, SO_REUSEADDR, 
            (char *) &val, sizeof(val));
        /* set the backlog and listen */
        err = socket_strerror(socket_listen(&tcp->sock, backlog));
        if (err) {
            socket_destroy(&tcp->sock);
            lua_pushnil(L);
            lua_pushstring(L, err); 
            return 2;
        }
        auxiliar_setclass(L, "tcp{server}", -1);
        return 1;
    } else {
        lua_pushnil(L);
        lua_pushstring(L, err);
        return 2;
    }
}

static const char *tryconnect6(const char *remoteaddr, const char *remoteserv,
    struct addrinfo *connecthints, p_tcp tcp) {
    struct addrinfo *iterator = NULL, *resolved = NULL;
    const char *err = NULL;
    /* try resolving */
    err = socket_gaistrerror(getaddrinfo(remoteaddr, remoteserv, 
                connecthints, &resolved));
    if (err != NULL) {
        if (resolved) freeaddrinfo(resolved);
        return err; 
    }
    /* iterate over all returned addresses trying to connect */
    for (iterator = resolved; iterator; iterator = iterator->ai_next) {
        p_timeout tm = timeout_markstart(&tcp->tm);
        /* create new socket if one wasn't created by the bind stage */
        if (tcp->sock == SOCKET_INVALID) {
            err = socket_strerror(socket_create(&tcp->sock, 
                iterator->ai_family, iterator->ai_socktype, 
                iterator->ai_protocol));
            if (err != NULL) {
                freeaddrinfo(resolved);
                return err;
            }
            /* all sockets initially non-blocking */
            socket_setnonblocking(&tcp->sock);
        }
        /* finally try connecting to remote address */
        err = socket_strerror(socket_connect(&tcp->sock, 
            (SA *) iterator->ai_addr,
            iterator->ai_addrlen, tm));
        /* if success, break out of loop */
        if (err == NULL) break;
    }

    freeaddrinfo(resolved);
    /* here, if err is set, we failed */
    return err;
}

static int global_connect6(lua_State *L) {
    const char *remoteaddr = luaL_checkstring(L, 1);
    const char *remoteserv = luaL_checkstring(L, 2);
    const char *localaddr  = luaL_optstring(L, 3, NULL);
    const char *localserv  = luaL_optstring(L, 4, "0");
    p_tcp tcp = (p_tcp) lua_newuserdata(L, sizeof(t_tcp));
    struct addrinfo bindhints, connecthints;
    const char *err = NULL;
    /* initialize tcp structure */
    io_init(&tcp->io, (p_send) socket_send, (p_recv) socket_recv, 
            (p_error) socket_ioerror, &tcp->sock);
    timeout_init(&tcp->tm, -1, -1);
    buffer_init(&tcp->buf, &tcp->io, &tcp->tm);
    tcp->sock = SOCKET_INVALID;
    /* allow user to pick local address and port */
    memset(&bindhints, 0, sizeof(bindhints));
    bindhints.ai_socktype = SOCK_STREAM;
    bindhints.ai_family = PF_UNSPEC;
    bindhints.ai_flags = AI_PASSIVE;
    if (localaddr) {
        err = trybind6(localaddr, localserv, &bindhints, tcp);
        if (err) {
            lua_pushnil(L);
            lua_pushstring(L, err);
            return 2;
        }
    }
    /* try to connect to remote address and port */
    memset(&connecthints, 0, sizeof(connecthints));
    connecthints.ai_socktype = SOCK_STREAM;
    /* make sure we try to connect only to the same family */
    connecthints.ai_family = bindhints.ai_family; 
    err = tryconnect6(remoteaddr, remoteserv, &connecthints, tcp);
    if (err) {
        socket_destroy(&tcp->sock);
        lua_pushnil(L);
        lua_pushstring(L, err);
        return 2;
    }
    auxiliar_setclass(L, "tcp{client}", -1);
    return 1;
}