/**
 * @file PacketRouter.c
 * @author Ambroz Bizjak <ambrop7@gmail.com>
 * 
 * @section LICENSE
 * 
 * This file is part of BadVPN.
 * 
 * BadVPN is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2
 * as published by the Free Software Foundation.
 * 
 * BadVPN is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include <flow/PacketRouter.h>

static void input_handler_done (PacketRouter *o, int data_len)
{
    ASSERT(data_len >= 0)
    ASSERT(data_len <= o->mtu - o->recv_offset)
    ASSERT(!BPending_IsSet(&o->next_job))
    DebugObject_Access(&o->d_obj);
    
    // set next job
    BPending_Set(&o->next_job);
    
    // call handler
    o->handler(o->user, RouteBufferSource_Pointer(&o->rbs), data_len);
    return;
}

static void next_job_handler (PacketRouter *o)
{
    DebugObject_Access(&o->d_obj);
    
    // receive
    PacketRecvInterface_Receiver_Recv(o->input, RouteBufferSource_Pointer(&o->rbs) + o->recv_offset);
}

int PacketRouter_Init (PacketRouter *o, int mtu, int recv_offset, PacketRecvInterface *input, PacketRouter_handler handler, void *user, BPendingGroup *pg)
{
    ASSERT(mtu >= 0)
    ASSERT(recv_offset >= 0)
    ASSERT(recv_offset <= mtu)
    ASSERT(PacketRecvInterface_GetMTU(input) <= mtu - recv_offset)
    
    // init arguments
    o->mtu = mtu;
    o->recv_offset = recv_offset;
    o->input = input;
    o->handler = handler;
    o->user = user;
    
    // init input
    PacketRecvInterface_Receiver_Init(o->input, (PacketRecvInterface_handler_done)input_handler_done, o);
    
    // init RouteBufferSource
    if (!RouteBufferSource_Init(&o->rbs, mtu)) {
        goto fail0;
    }
    
    // init next job
    BPending_Init(&o->next_job, pg, (BPending_handler)next_job_handler, o);
    
    // receive
    PacketRecvInterface_Receiver_Recv(o->input, RouteBufferSource_Pointer(&o->rbs) + o->recv_offset);
    
    DebugObject_Init(&o->d_obj);
    
    return 1;
    
fail0:
    return 0;
}

void PacketRouter_Free (PacketRouter *o)
{
    DebugObject_Free(&o->d_obj);
    
    // free next job
    BPending_Free(&o->next_job);
    
    // free RouteBufferSource
    RouteBufferSource_Free(&o->rbs);
}

int PacketRouter_Route (PacketRouter *o, int len, RouteBuffer *output, uint8_t **next_buf, int copy_offset, int copy_len)
{
    ASSERT(len >= 0)
    ASSERT(len <= o->mtu)
    ASSERT(RouteBuffer_GetMTU(output) == o->mtu)
    ASSERT(copy_offset >= 0)
    ASSERT(copy_offset <= o->mtu)
    ASSERT(copy_len >= 0)
    ASSERT(copy_len <= o->mtu - copy_offset)
    ASSERT(BPending_IsSet(&o->next_job))
    DebugObject_Access(&o->d_obj);
    
    if (!RouteBufferSource_Route(&o->rbs, len, output, copy_offset, copy_len)) {
        return 0;
    }
    
    if (next_buf) {
        *next_buf = RouteBufferSource_Pointer(&o->rbs);
    }
    
    return 1;
}

void PacketRouter_AssertRoute (PacketRouter *o)
{
    ASSERT(BPending_IsSet(&o->next_job))
    DebugObject_Access(&o->d_obj);
}