lwip

LwIP

Dies ist ein Zweig von liblwip mit einem einfachen Build-System.

Merkmale

• UDP: Empfangen von Paketen zulassen, die nicht für localhost bestimmt sind.
• TCP: Zulassen, dass Verbindungen akzeptiert werden, die nicht für localhost bestimmt sind.

Beispiele

TCP

 static void
gateway_init ( void )
{
    // Init netif
    netif_set_up ( & netif );
    netif_set_link_up ( & netif );
    netif_set_default ( & netif );

    // Allow to pretend TCP on this netif
    netif_set_flags ( & netif , NETIF_FLAG_PRETEND_TCP );

    tcp = tcp_new_ip_type ( IPADDR_TYPE_ANY );

    // Bind TCP to netif first
    tcp_bind_netif ( tcp , & netif );

    // Bind to accept incoming connections to other hosts
    tcp_bind ( tcp , NULL , 0 );

    tcp_listen ( tcp );
    tcp_accept ( tcp , tcp_accept_handler );
}

static err_t
tcp_accept_handler ( void * arg , struct tcp_pcb * pcb , err_t err )
{
    // Accept new TCP connection
    // @pcb->local_ip: The real destination address
    // @pcb->local_port: The real destination port
    // @pcb->remote_ip: The real source address
    // @pcb->remote_port: The real source port
}

UDP

 static void
gateway_init ( void )
{
    // Init netif
    netif_set_up ( & netif );
    netif_set_link_up ( & netif );
    netif_set_default ( & netif );

    // Allow to pretend UDP on this netif
    netif_set_flags ( & netif , NETIF_FLAG_PRETEND_UDP );

    udp = udp_new_ip_type ( IPADDR_TYPE_ANY );

    // Bind TCP to netif first
    udp_bind_netif ( udp , & netif );

    // Bind to receive packets to other hosts
    udp_bind ( udp , NULL , 0 );

    udp_recv ( udp , udp_accept_handler , NULL );
}

static void
udp_accept_handler ( void * arg , struct udp_pcb * pcb , struct pbuf * p ,
                  const ip_addr_t * addr , u16_t port )
{
    // Similar to TCP accept, receive packets on new UDP PCB.
    // @pcb: An new UDP PCB for sending and receiving.
    // @p: Unused
    // @addr: Unused
    // @port: Unused
    udp_recv ( pcb , udp_recv_handler , NULL );
}

static void
udp_recv_handler ( void * arg , struct udp_pcb * pcb , struct pbuf * p ,
                  const ip_addr_t * addr , u16_t port )
{
    // Receive UDP packets

    // @pcb->local_ip: The real destination address
    // @pcb->local_port: The real destination port
    // @pcb->remote_ip: The real source address
    // @pcb->remote_port: The real source port
    // @addr: Unused
    // @port: Unused

    // Send with source address
    udp_sendfrom ( pcb , p , real_src_ip , real_src_port );
    pbuf_free ( p );
}

Wie man baut

Unix :

git clone https://gitlab.com/hev/lwip
cd lwip
make

Android :

mkdir lwip
cd lwip
git clone https://gitlab.com/hev/lwip jni
ndk-build

Windows :

git clone https://gitlab.com/hev/lwip
cd lwip
make CROSS_PREFIX=x86_64-w64-mingw32-

Stromaufwärts

https://savannah.nongnu.org/projects/lwip