This is a branch of liblwip with a simple build system.
- UDP: Allow receiving packets are not destined to localhost.
- TCP: Allow accepting connections are not destined to localhost.
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
}
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);
}
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