It's the included example:
https://raw.github.com/beaucollins/arduino-projects/master/libraries/SerialIP/examples/HelloWorldServer/HelloWorldServer.pde
/*
* SerialIP Hello World example.
*
* SerialIP is a TCP/IP stack that can be used over a serial port (a bit
* like a dial-up Internet connection, but without the modem.) It works with
* stock Arduinos (no shields required.) When attached to a PC supporting
* SLIP, the Arduino can host network servers and access the Internet (if the
* PC is configured to share its Internet connection of course!)
*
* SerialIP uses the fine uIP stack by Adam Dunkels <adam@sics.se>
*
* For more information see the SerialIP page on the Arduino wiki:
* <http://www.arduino.cc/playground/Code/SerialIP>
*
* -----------------
*
* This Hello World example sets up a server at 192.168.5.2 on port 1000.
* Telnet here to access the service. The uIP stack will also respond to
* pings to test if you have successfully established a SLIP connection to
* the Arduino.
*
* SLIP connection set up under Linux:
*
* # modprobe slip
* # slattach -L -s 115200 -p slip /dev/ttyUSB0 (see note below)
* # ifconfig sl0 192.168.5.1 dstaddr 192.168.5.2
*
* # ping 192.168.5.2
* # telnet 192.168.5.2 1000
*
* Here 192.168.5.1 is the address you will give to your PC, and it must be
* unique on your LAN. 192.168.5.2 is the IP you will give the Arduino. It
* must also be unique, and must match the address the Arduino is expecting
* as set by the "myIP" variable below.
*
* Note that slattach won't return so you'll need to run ifconfig from
* another terminal. You can press Ctrl+C to kill slattach and release the
* serial port, e.g. to upload another sketch.
*
* This example was based upon uIP hello-world by Adam Dunkels <adam@sics.se>
* Ported to the Arduino IDE by Adam Nielsen <malvineous@shikadi.net>
*/
#include <SerialIP.h>
// The connection_data struct needs to be defined in an external file.
#include "HelloWorldData.h"
void setup() {
// Set up the speed of our serial link.
Serial.begin(115200);
// Tell SerialIP which serial port to use (some boards have more than one.)
// Currently this is limited to HardwareSerial ports, until both it and
// SoftwareSerial inherit from a common base class.
SerialIP.use_device(Serial);
// We're going to be handling uIP events ourselves. Perhaps one day a simpler
// interface will be implemented for the Arduino IDE, but until then...
SerialIP.set_uip_callback(uip_callback);
// Set the IP address we'll be using. Make sure this doesn't conflict with
// any IP addresses or subnets on your LAN or you won't be able to connect to
// either the Arduino or your LAN...
IP_ADDR myIP = {192,168,5,2};
IP_ADDR subnet = {255,255,255,0};
SerialIP.begin(myIP, subnet);
// If you'll be making outgoing connections from the Arduino to the rest of
// the world, you'll need a gateway set up.
//IP_ADDR gwIP = {192,168,5,1};
//SerialIP.set_gateway(gwIP);
// Listen for incoming connections on TCP port 1000. Each incoming
// connection will result in the uip_callback() function being called.
SerialIP.listen(1000);
}
void loop() {
// Check the serial port and process any incoming data.
SerialIP.tick();
// We can do other things in the loop, but be aware that the loop will
// briefly pause while IP data is being processed.
}
void uip_callback(uip_tcp_appstate_t *s)
{
if (uip_connected()) {
// We want to store some data in our connections, so allocate some space
// for it. The connection_data struct is defined in a separate .h file,
// due to the way the Arduino IDE works. (typedefs come after function
// definitions.)
connection_data *d = (connection_data *)malloc(sizeof(connection_data));
// Save it as SerialIP user data so we can get to it later.
s->user = d;
// The protosocket's read functions need a per-connection buffer to store
// data they read. We've got some space for this in our connection_data
// structure, so we'll tell uIP to use that.
PSOCK_INIT(&s->p, d->input_buffer, sizeof(d->input_buffer));
}
// Call/resume our protosocket handler.
handle_connection(s, (connection_data *)s->user);
// If the connection has been closed, release the data we allocated earlier.
if (uip_closed()) {
if (s->user) free(s->user);
s->user = NULL;
}
}
// This function is going to use uIP's protosockets to handle the connection.
// This means it must return int, because of the way the protosockets work.
// In a nutshell, when a PSOCK_* macro needs to wait for something, it will
// return from handle_connection so that other work can take place. When the
// event is triggered, uip_callback() will call this function again and the
// switch() statement (see below) will take care of resuming execution where
// it left off. It *looks* like this function runs from start to finish, but
// that's just an illusion to make it easier to code :-)
int handle_connection(uip_tcp_appstate_t *s, connection_data *d)
{
// All protosockets must start with this macro. Its internal implementation
// is that of a switch() statement, so all code between PSOCK_BEGIN and
// PSOCK_END is actually inside a switch block. (This means for example,
// that you can't declare variables in the middle of it!)
PSOCK_BEGIN(&s->p);
// Send some text over the connection.
PSOCK_SEND_STR(&s->p, "Hello. What is your name?\n");
// Read some returned text into the input buffer we set in PSOCK_INIT. Data
// is read until a newline (\n) is received, or the input buffer gets filled
// up. (Which, at 16 chars by default, isn't hard!)
PSOCK_READTO(&s->p, '\n');
// Since any subsequent PSOCK_* functions would overwrite the buffer, we
// need to make a copy of it first. We can't use a local variable for this,
// because any PSOCK_* macro may make the function return and resume later,
// thus losing the data in any local variables. This is why uip_callback
// has allocated the connection_data structure for us to use instead. (You
// can add/remove other variables in this struct to store different data.
// See the other file in this sketch, serialip_conn.h)
strncpy(d->name, d->input_buffer, sizeof(d->name));
// Note that this will misbehave when the input buffer overflows (i.e.
// more than 16 characters are typed in) but hey, this is supposed to be
// a simple example. Fixing this problem will be left as an exercise for
// the reader :-)
// Send some more data over the connection.
PSOCK_SEND_STR(&s->p, "Hello ");
PSOCK_SEND_STR(&s->p, d->name);
// Disconnect.
PSOCK_CLOSE(&s->p);
// All protosockets must end with this macro. It closes the switch().
PSOCK_END(&s->p);
}
