/* 
 *------------------------------------------------------------------
 * socksvr_vlib.c
 *
 * Copyright (c) 2009 Cisco and/or its affiliates.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *------------------------------------------------------------------
 */

#include <sys/types.h> 
#include <sys/socket.h>
#include <netinet/in.h>
#include <sys/ioctl.h>
#include <vppinfra/byte_order.h>

#include <fcntl.h>
#include <sys/stat.h>

#include <vlibsocket/api.h>
#include <vlibmemory/api.h>

#include <vlibsocket/vl_socket_msg_enum.h> /* enumerate all vlib messages */

#define vl_typedefs             /* define message structures */
#include <vlibsocket/vl_socket_api_h.h> 
#undef vl_typedefs

/* instantiate all the print functions we know about */
#define vl_print(handle, ...) vlib_cli_output (handle, __VA_ARGS__)
#define vl_printfun
#include <vlibsocket/vl_socket_api_h.h> 
#undef vl_printfun

/* instantiate all the endian swap functions we know about */
#define vl_endianfun
#include <vlibsocket/vl_socket_api_h.h> 
#undef vl_endianfun

socket_main_t socket_main;

void dump_socket_clients (vlib_main_t *vm, api_main_t *am)
{
    vl_api_registration_t *reg;
    socket_main_t *sm = &socket_main;
    unix_main_t *um = &unix_main;
    unix_file_t *f;

    /* 
     * Must have at least one active client, not counting the
     * REGISTRATION_TYPE_SOCKET_LISTEN bind/accept socket
     */
    if (pool_elts (sm->registration_pool) < 2)
        return;

    vlib_cli_output (vm, "TCP socket clients");
    vlib_cli_output (vm, "%16s %8s", "Name", "Fildesc");
    pool_foreach (reg, sm->registration_pool, 
    ({
        if (reg->registration_type == REGISTRATION_TYPE_SOCKET_SERVER) {
            f = pool_elt_at_index (um->file_pool, reg->unix_file_index);
            vlib_cli_output (vm, "%16s %8d",
                             reg->name, f->file_descriptor);
        }
    }));
}

void 
vl_socket_api_send (vl_api_registration_t *rp, u8 *elem) 
{
    u32 nbytes = 4; /* for the length... */
    u16 msg_id = ntohs(*(u16 *)elem);
    u32 msg_length;
    u32 tmp;
    api_main_t *am = &api_main;

    ASSERT(rp->registration_type > REGISTRATION_TYPE_SHMEM);

    if (msg_id >= vec_len(am->api_trace_cfg)) {
        clib_warning("id out of range: %d", msg_id);
        vl_msg_api_free((void *)elem);
        return;
    }

    msg_length = am->api_trace_cfg[msg_id].size;
    nbytes += msg_length;
    tmp = clib_host_to_net_u32 (nbytes);

    vl_socket_add_pending_output (rp->unix_file_index 
                                  + unix_main.file_pool, 
                                  rp->vl_api_registration_pool_index
                                  + socket_main.registration_pool,
                                  (u8 *) &tmp, 
                                  sizeof(tmp));
    vl_socket_add_pending_output (rp->unix_file_index 
                                  + unix_main.file_pool, 
                                  rp->vl_api_registration_pool_index
                                  + socket_main.registration_pool,
                                  elem, msg_length);
    vl_msg_api_free((void *)elem);
}

void vl_socket_api_send_with_data (vl_api_registration_t *rp, 
                                   u8 *elem, u8 *data_vector)
{
    u32 nbytes = 4; /* for the length... */
    u16 msg_id = ntohs(*(u16 *)elem);
    u32 msg_length;
    u32 tmp;
    api_main_t *am = &api_main;
        
    ASSERT(rp->registration_type > REGISTRATION_TYPE_SHMEM);

    if (msg_id >= vec_len(am->api_trace_cfg)) {
        clib_warning("id out of range: %d", msg_id);
        vec_free(data_vector);
        vl_msg_api_free((void *)elem);
        return;
    }

    msg_length = am->api_trace_cfg[msg_id].size;
    nbytes += msg_length;
    nbytes += vec_len(data_vector);

    /* Length in network byte order */
    tmp = clib_host_to_net_u32(nbytes);

    vl_socket_add_pending_output (rp->unix_file_index 
                                  + unix_main.file_pool, 
                                  rp->vl_api_registration_pool_index
                                  + socket_main.registration_pool,
                                  (u8 *) &tmp, 
                                  sizeof(tmp));
    vl_socket_add_pending_output (rp->unix_file_index 
                                  + unix_main.file_pool, 
                                  rp->vl_api_registration_pool_index
                                  + socket_main.registration_pool,
                                  elem, msg_length);
    vl_socket_add_pending_output (rp->unix_file_index 
                                  + unix_main.file_pool, 
                                  rp->vl_api_registration_pool_index
                                  + socket_main.registration_pool,
                                  data_vector, vec_len(data_vector));
    vl_msg_api_free((void *)elem);
}

static inline void 
vl_socket_api_send_with_length_internal (vl_api_registration_t *rp, 
                                         u8 *elem, u32 msg_length, int free)
{
    u32 nbytes = 4; /* for the length... */
    u16 msg_id = ntohs(*(u16 *)elem);
    u32 tmp;
    api_main_t *am = &api_main;
        
    ASSERT(rp->registration_type > REGISTRATION_TYPE_SHMEM);

    if (msg_id >= vec_len(am->api_trace_cfg)) {
        clib_warning("id out of range: %d", msg_id);
        if (free)
            vl_msg_api_free((void *)elem);
        return;
    }

    nbytes += msg_length;

    /* Length in network byte order */
    tmp = clib_host_to_net_u32(nbytes);

    vl_socket_add_pending_output (rp->unix_file_index 
                                  + unix_main.file_pool, 
                                  rp->vl_api_registration_pool_index
                                  + socket_main.registration_pool,
                                  (u8 *) &tmp, 
                                  sizeof(tmp));
    vl_socket_add_pending_output (rp->unix_file_index 
                                  + unix_main.file_pool, 
                                  rp->vl_api_registration_pool_index
                                  + socket_main.registration_pool,
                                  elem, msg_length);
    if (free)
        vl_msg_api_free((void *)elem);
}

void vl_socket_api_send_with_length (vl_api_registration_t *rp, 
                                     u8 *elem, u32 msg_length)
{
    vl_socket_api_send_with_length_internal(rp,elem,msg_length, 1 /* free */);
}

void vl_socket_api_send_with_length_no_free (vl_api_registration_t *rp, 
                                             u8 *elem, u32 msg_length)
{
    vl_socket_api_send_with_length_internal(rp,elem,msg_length, 0 /* free */);
}

void vl_free_socket_registration_index (u32 pool_index)
{
    vl_api_registration_t *rp;
    if (pool_is_free_index (socket_main.registration_pool, pool_index)) {
        clib_warning ("main pool index %d already free", pool_index);
        return;
    }
    rp = pool_elt_at_index (socket_main.registration_pool, pool_index);

    ASSERT(rp->registration_type != REGISTRATION_TYPE_FREE);
    vec_free (rp->name);
    vec_free (rp->unprocessed_input);
    vec_free (rp->output_vector);
    rp->registration_type = REGISTRATION_TYPE_FREE;
    pool_put (socket_main.registration_pool, rp);
}

static inline void
socket_process_msg (unix_file_t *uf, vl_api_registration_t *rp, i8 *input_v)
{
    u8 *the_msg = (u8 *)(input_v+sizeof(u32));
    socket_main.current_uf = uf;
    socket_main.current_rp = rp;
    vl_msg_api_socket_handler (the_msg);
    socket_main.current_uf = 0;
    socket_main.current_rp = 0;
}

clib_error_t * vl_socket_read_ready (unix_file_t * uf)
{
    unix_main_t * um = &unix_main;
    vl_api_registration_t * rp;
    int n;
    i8 *msg_buffer=0;
    u32 msg_len;
    u32 save_input_buffer_length = vec_len(socket_main.input_buffer);
    
    rp = pool_elt_at_index (socket_main.registration_pool, uf->private_data);
    
    n = read (uf->file_descriptor, socket_main.input_buffer, 
              vec_len(socket_main.input_buffer));

    if (n <= 0 && errno != EAGAIN) {
        unix_file_del (um, uf);

        if (!pool_is_free (socket_main.registration_pool, rp)) {
            u32 index = rp - socket_main.registration_pool;
            vl_free_socket_registration_index (index);
        } else {
            clib_warning("client index %d already free?", 
                         rp->vl_api_registration_pool_index);
        }
        return 0;
    }
  
    _vec_len(socket_main.input_buffer) = n;

    /* 
     * Look for bugs here. This code is tricky because
     * data read from a stream socket does honor message
     * boundaries. In the case of a long message (>4K bytes)
     * we have to do (at least) 2 reads, etc.
     */
    do {
        if (vec_len(rp->unprocessed_input)) {
            vec_append(rp->unprocessed_input, socket_main.input_buffer);
            msg_buffer = rp->unprocessed_input;
            msg_len = rp->unprocessed_msg_length;
        } else {
            msg_buffer = socket_main.input_buffer;
            msg_len = 0;
        }

        if (msg_len == 0) {
            /* Length may be split across two reads */
            if (vec_len(msg_buffer) < sizeof (u32))
                goto save_and_split;

            /* total length, including msg_len itself, in network byte order */
            msg_len = clib_net_to_host_u32 (*((u32 *)msg_buffer));
        }

        /* Happens if the client sent msg_len == 0 */
        if (msg_len == 0) {
            clib_warning ("msg_len == 0");
            goto turf_it;
        }

        /* We don't have the entire message yet. */
        if (msg_len > vec_len(msg_buffer)) {
        save_and_split:
            /*
             * if we were using the shared input buffer, 
             * save the fragment.
             */
            if (msg_buffer == socket_main.input_buffer) {
                ASSERT(vec_len(rp->unprocessed_input) == 0);
                vec_validate (rp->unprocessed_input, vec_len (msg_buffer)-1);
                memcpy (rp->unprocessed_input, msg_buffer, vec_len(msg_buffer));
                _vec_len (rp->unprocessed_input) = vec_len (msg_buffer);
            }
            _vec_len(socket_main.input_buffer) = save_input_buffer_length;
            rp->unprocessed_msg_length = msg_len;
            return 0;
        }

        socket_process_msg (uf, rp, msg_buffer);
        if (n > msg_len)
            vec_delete(msg_buffer, msg_len, 0);
        else
            _vec_len(msg_buffer) = 0;
        n -= msg_len;
        msg_len = 0;
        rp->unprocessed_msg_length = 0;
    } while (n > 0);

turf_it:
    _vec_len(socket_main.input_buffer) = save_input_buffer_length;

    return 0;
}

void
vl_socket_add_pending_output (unix_file_t * uf,
                              vl_api_registration_t * rp,
                              u8 * buffer,
                              uword buffer_bytes)
{
    unix_main_t * um = &unix_main;

    vec_add (rp->output_vector, buffer, buffer_bytes);
    if (vec_len (rp->output_vector) > 0) {
        int skip_update = 0 != (uf->flags & UNIX_FILE_DATA_AVAILABLE_TO_WRITE);
        uf->flags |= UNIX_FILE_DATA_AVAILABLE_TO_WRITE;
        if (! skip_update)
            um->file_update (uf, UNIX_FILE_UPDATE_MODIFY);
    }
}

static void
socket_del_pending_output (unix_file_t * uf,
                           vl_api_registration_t * rp,
                           uword n_bytes)
{
    unix_main_t * um = &unix_main;

    vec_delete (rp->output_vector, n_bytes, 0);
    if (vec_len (rp->output_vector) <= 0)
    {
        int skip_update = 0 == (uf->flags & UNIX_FILE_DATA_AVAILABLE_TO_WRITE);
        uf->flags &= ~UNIX_FILE_DATA_AVAILABLE_TO_WRITE;
        if (! skip_update)
            um->file_update (uf, UNIX_FILE_UPDATE_MODIFY);
    }
}

clib_error_t * 
vl_socket_write_ready (unix_file_t * uf)
{
    unix_main_t * um = &unix_main;
    vl_api_registration_t * rp;
    int n;

    rp = pool_elt_at_index (socket_main.registration_pool, uf->private_data);
    
    /* Flush output vector. */
    n = write (uf->file_descriptor,
               rp->output_vector, vec_len (rp->output_vector));

    if (n < 0) {
#if DEBUG > 2
        clib_warning ("write error, close the file...\n");
#endif
        unix_file_del (um, uf);

        vl_free_socket_registration_index (rp - socket_main.registration_pool);
        return 0;
    }

    else if (n > 0)
        socket_del_pending_output (uf, rp, n);

    return 0;
}

clib_error_t * vl_socket_error_ready (unix_file_t * uf)
{
    vl_api_registration_t * rp;
    unix_main_t * um = &unix_main;

    rp = pool_elt_at_index (socket_main.registration_pool, uf->private_data);
    unix_file_del (um, uf);
    vl_free_socket_registration_index (rp - socket_main.registration_pool);

    return 0;
}

void socksvr_file_add (unix_main_t *um, int fd)
{
    vl_api_registration_t *rp;
    unix_file_t template = {0};
    
    pool_get (socket_main.registration_pool, rp);
    memset(rp, 0, sizeof(*rp));
    
    template.read_function = vl_socket_read_ready;
    template.write_function = vl_socket_write_ready;
    template.error_function = vl_socket_error_ready;
    template.file_descriptor = fd;
    template.private_data = rp - socket_main.registration_pool;
    
    rp->registration_type = REGISTRATION_TYPE_SOCKET_SERVER;
    rp->vl_api_registration_pool_index = rp - socket_main.registration_pool;
    rp->unix_file_index = unix_file_add (um, &template);
}

static clib_error_t * socksvr_accept_ready (unix_file_t * uf)
{
    unix_main_t * um = &unix_main;
    struct sockaddr_in client_addr;
    int client_fd;
    int client_len;

    client_len = sizeof(client_addr);
    
    /*
     * Supposedly acquires the non-blocking attrib from the
     * server socket. 
     */
    client_fd = accept (uf->file_descriptor, 
                        (struct sockaddr *)&client_addr, 
                        (socklen_t *)&client_len);

    if (client_fd < 0)
        return clib_error_return_unix (0, "socksvr_accept_ready: accept");

    socksvr_file_add (um, client_fd);
    return 0;
}

static clib_error_t * socksvr_bogus_write (unix_file_t * uf)
{
    clib_warning ("why am I here?");
    return 0;
}

/*
 * vl_api_sockclnt_create_t_handler
 */
void vl_api_sockclnt_create_t_handler (vl_api_sockclnt_create_t *mp)
{
    vl_api_registration_t *regp;
    vl_api_sockclnt_create_reply_t *rp;
    int rv = 1;

    regp = socket_main.current_rp;

    ASSERT(regp->registration_type == REGISTRATION_TYPE_SOCKET_SERVER);

    regp->name = format(0, "%s%c", mp->name, 0);

    rp = vl_msg_api_alloc(sizeof(*rp));
    rp->_vl_msg_id = htons(VL_API_SOCKCLNT_CREATE_REPLY);
    rp->handle = (uword)regp;
    rp->index = (uword)regp->vl_api_registration_pool_index;
    rp->context = mp->context;
    rp->response = htonl(rv);

    vl_msg_api_send (regp, (u8 *)rp);
}

/*
 * vl_api_sockclnt_delete_t_handler
 */
void vl_api_sockclnt_delete_t_handler (vl_api_sockclnt_delete_t *mp)
{
    vl_api_registration_t *regp;
    vl_api_sockclnt_delete_reply_t *rp;

    if (!pool_is_free_index(socket_main.registration_pool, mp->index)) {
        regp = pool_elt_at_index(socket_main.registration_pool, mp->index);

        rp = vl_msg_api_alloc(sizeof(*rp));
        rp->_vl_msg_id = htons(VL_API_SOCKCLNT_DELETE_REPLY);
        rp->handle = mp->handle;
        rp->response = htonl(1);
        
        vl_msg_api_send (regp, (u8 *)rp);

        unix_file_del (&unix_main, 
                       unix_main.file_pool + regp->unix_file_index);

        vl_free_socket_registration_index (mp->index);
    } else {
        clib_warning("unknown client ID %d", mp->index);
    }
}

#define foreach_vlib_api_msg                    \
_(SOCKCLNT_CREATE, sockclnt_create)             \
_(SOCKCLNT_DELETE, sockclnt_delete)             

static clib_error_t *socksvr_api_init (vlib_main_t * vm)
{
    unix_main_t * um = &unix_main;
    unix_file_t template = {0};
    int sockfd;
    int one = 1;
    int rv;
    struct sockaddr_in serv_addr;
    vl_api_registration_t *rp;
    u16 portno;
    u32 bind_address;

#define _(N,n)                                                  \
    vl_msg_api_set_handlers(VL_API_##N, #n,                     \
                           vl_api_##n##_t_handler,              \
                           vl_noop_handler,                     \
                           vl_api_##n##_t_endian,               \
                           vl_api_##n##_t_print,                \
                           sizeof(vl_api_##n##_t), 1); 
    foreach_vlib_api_msg;
#undef _

    vec_resize(socket_main.input_buffer, 4096);

    /* Set up non-blocking server socket on CLIENT_API_SERVER_PORT */
    sockfd = socket(AF_INET, SOCK_STREAM, 0);

    if (sockfd < 0) {
        return clib_error_return_unix (0, "socket");
    }

    rv = ioctl (sockfd, FIONBIO, &one);
    if (rv < 0) {
        return clib_error_return_unix (0, "FIONBIO");
    }

    rv = setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
    if (rv < 0) {
        return clib_error_return_unix (0, "SO_REUSEADDR");
    }

    bzero((char *) &serv_addr, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;

    if (socket_main.bind_address)
        bind_address = socket_main.bind_address;
    else
        bind_address = INADDR_LOOPBACK;

    if (socket_main.portno) 
        portno = socket_main.portno;
    else
        portno = SOCKSVR_DEFAULT_PORT;

    serv_addr.sin_port = clib_host_to_net_u16 (portno);
    serv_addr.sin_addr.s_addr = clib_host_to_net_u32(bind_address);

    if (bind(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0) {
        return clib_error_return_unix (0, "bind");
    }
           
    rv = listen(sockfd,5);
    if (rv < 0) {
        return clib_error_return_unix (0, "listen");
    }

    pool_get (socket_main.registration_pool, rp);
    memset(rp, 0, sizeof(*rp));
    
    rp->registration_type = REGISTRATION_TYPE_SOCKET_LISTEN;

    template.read_function = socksvr_accept_ready;
    template.write_function = socksvr_bogus_write;
    template.file_descriptor = sockfd;
    template.private_data = rp - socket_main.registration_pool;
    
    rp->unix_file_index = unix_file_add (um, &template);
    return 0;
}

static clib_error_t *
socket_exit (vlib_main_t * vm)
{
    unix_main_t * um = &unix_main;
    vl_api_registration_t *rp;

    /* Defensive driving in case something wipes out early */
    if (socket_main.registration_pool) {
        u32 index;
        pool_foreach (rp, socket_main.registration_pool, ({
            unix_file_del (um, um->file_pool + rp->unix_file_index);
            index = rp->vl_api_registration_pool_index;
            vl_free_socket_registration_index (index);
        }));
    }

    return 0;
}

VLIB_MAIN_LOOP_EXIT_FUNCTION (socket_exit);

static clib_error_t *
socksvr_config (vlib_main_t * vm, unformat_input_t * input)
{
    int portno;

    while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
    {
        if (unformat (input, "port %d", &portno)) {
            socket_main.portno = portno;
        } else {
            return clib_error_return (0, "unknown input '%U'",
                                      format_unformat_error, input);
        }
    }
    return socksvr_api_init (vm);
}

VLIB_CONFIG_FUNCTION (socksvr_config, "socksvr");

/* argument in host byte order */
void socksvr_set_port (u16 port)
{
    socket_main.portno = port;
}

/* argument in host byte order */
void socksvr_set_bind_address (u32 bind_address)
{
    socket_main.bind_address = bind_address;
}

clib_error_t *
vlibsocket_init (vlib_main_t * vm)
{
    return 0;
}

VLIB_INIT_FUNCTION (vlibsocket_init);