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tools/dirtpan/: quick and dirty IPv4 over 802.15.4 tunnel (in progress)

This commit is contained in:
Werner Almesberger 2011-05-11 07:39:23 -03:00
parent b82db55f4a
commit dbad7ae887
2 changed files with 551 additions and 0 deletions

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tools/dirtpan/Makefile Normal file
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#
# dirtpan/Makefile - Quick and dirty IPv4 over 802.15.4 tunnel
#
# Written 2011 by Werner Almesberger
# Copyright 2011 Werner Almesberger
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
MAIN = dirtpan
include ../Makefile.common
CFLAGS += -I. -I../../install/lowpan-tools-0.2.2/include/

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tools/dirtpan/dirtpan.c Normal file
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/*
* dirtpan/dirtpan.c - Quick and dirty IPv4 over 802.15.4 tunnel
*
* Written 2011 by Werner Almesberger
* Copyright 2011 Werner Almesberger
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#include <stdint.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <fcntl.h>
#include <assert.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/select.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <linux/if.h>
#include <linux/if_tun.h>
#include <ieee802154.h>
/*
* Control byte structure:
*
* +--7--+--6--+--5--+--4--+--3--+--2--+--1--+
* | 0 | 0 | 0 | 0 | seq | pck_type |
* +-----+-----+-----+-----+-----+-----+-----+
*/
#define SEQ 4
#define PT_MASK 3
enum packet_type {
pt_first = 0,
pt_next = 1,
pt_ack = 2,
};
#define TUN_DEV "/dev/net/tun"
#define MAX_FRAG (127-11-2-1) /* MHDR, FCS, control byte */
#define MAX_PACKET 2000
#define MAX_TRIES 5
#define T_REASS_MS 200
#define T_ACK_MS 50
static enum state {
s_idle,
s_tx,
s_rx,
} state = s_idle;
static int tun, net;
static uint8_t packet[MAX_PACKET+1];
static void *pos;
static int left;
static int my_seq = 0, peer_seq;
static int retries;
static int debug = 0;
/* ----- Debugging --------------------------------------------------------- */
static void debug_label(const char *label)
{
const char *t;
switch (state) {
case s_idle:
t = "--";
break;
case s_tx:
t = "tx";
break;
case s_rx:
t = "rx";
break;
default:
t = "???";
break;
}
fprintf(stderr, "%s(%s)", label, t);
}
static void dump(const void *buf, int size)
{
const uint8_t *p = buf;
while (size--) {
fprintf(stderr, "%s%02x", p == buf ? "" : " ", *p);
p++;
}
}
static void debug_ip(const char *label, void *buf, int size)
{
if (!debug)
return;
debug_label(label);
fprintf(stderr, ", %d: ", size);
dump(buf, size);
fprintf(stderr, "\n");
}
static void debug_dirt(const char *label, void *buf, int size)
{
const uint8_t *p = buf;
if (!debug)
return;
debug_label(label);
fprintf(stderr, ", %d", size);
if (size) {
fprintf(stderr, ": %02x(%c%d) ",
*p, "FNA?"[*p & PT_MASK], *p & SEQ ? 0 : 1);
dump(buf+1, size-1);
}
fprintf(stderr, "\n");
}
static void debug_event(const char *label)
{
if (!debug)
return;
debug_label(label);
fprintf(stderr, "\n");
}
/* ----- Timers ------------------------------------------------------------ */
static struct timeval t0;
static void start_timer(void)
{
gettimeofday(&t0, NULL);
}
static struct timeval *timeout(int ms)
{
static struct timeval t;
gettimeofday(&t, NULL);
t.tv_sec -= t0.tv_sec;
t.tv_usec -= t0.tv_usec;
t.tv_usec += 1000*ms;
while (t.tv_usec < 0) {
t.tv_sec--;
t.tv_usec += 1000000;
}
while (t.tv_usec > 1000000) {
t.tv_sec++;
t.tv_usec -= 1000000;
}
if (t.tv_sec < 0)
t.tv_sec = t.tv_usec = 0;
return &t;
}
/* ----- Packet/frame delivery --------------------------------------------- */
static inline int send_size(void)
{
return left > MAX_FRAG ? MAX_FRAG : left;
}
static void write_buf(int fd, void *buf, int size)
{
ssize_t wrote;
wrote = write(fd, buf, size);
if (wrote < 0) {
perror("write");
return;
}
if (wrote != size)
fprintf(stderr, "short write: %d < %d\n", (int) wrote, size);
}
static void send_frame(void *buf, int size)
{
debug_dirt("->", buf, size);
write_buf(net, buf, size);
}
static void send_more(void)
{
uint8_t *p = pos-1;
*p = (pos == packet+1 ? pt_first : pt_next) | (my_seq ? SEQ : 0);
send_frame(p, send_size()+1);
start_timer();
}
static void send_ack(int seq)
{
uint8_t ack = pt_ack | (seq ? SEQ : 0);
send_frame(&ack, 1);
}
/* ----- Main events ------------------------------------------------------- */
static void rx_pck(void *buf, int size)
{
const uint8_t *p = buf;
uint8_t ctrl, type, seq;
debug_dirt("-<", buf, size);
if (size < 1)
return;
ctrl = *p;
type = ctrl & PT_MASK;
seq = !!(ctrl & SEQ);
switch (state) {
case s_tx:
if (type != pt_ack)
return;
if (seq != my_seq)
return;
pos += send_size();
left -= send_size();
if (!left) {
state = s_idle;
return;
}
my_seq = !my_seq;
retries = 0;
send_more();
return;
case s_rx:
if (type == pt_first) {
start_timer();
state = s_idle;
break;
}
if (type != pt_next)
return;
if (seq == peer_seq) {
send_ack(seq); /* retransmission */
return;
}
goto recv_more;
case s_idle:
if (type == pt_first)
break;
if (type == pt_next) {
send_ack(seq); /* get rid of it */
return;
}
return;
default:
abort();
}
if (size < 5)
return;
left = p[3] << 8 | p[4];
if (left > MAX_PACKET+1)
return;
state = s_rx;
pos = packet;
recv_more:
if (left < size-1) {
send_ack(seq); /* get rid of it */
state = s_idle;
return;
}
memcpy(pos, buf+1, size-1);
pos += size-1;
left -= size-1;
peer_seq = seq;
send_ack(seq);
if (!left) {
debug_ip("<-", packet, pos-(void *) packet);
write_buf(tun, packet, pos-(void *) packet);
state = s_idle;
}
}
static void tx_pck(void *buf, int size)
{
const uint8_t *p = buf;
debug_ip(">-", buf, size);
assert(state == s_idle);
state = s_tx;
pos = packet+1;
left = p[2] << 8 | p[3];
assert(left <= MAX_PACKET);
assert(left == size);
/*
* We could avoid the memcpy by reading directly into "packet"
*/
memcpy(pos, buf, size);
my_seq = !my_seq;
retries = 0;
send_more();
}
static void ack_timeout(void)
{
debug_event("ACK-TO");
if (++retries == MAX_TRIES)
state = s_idle;
else
send_more();
}
static void reass_timeout(void)
{
debug_event("REASS-TO");
state = s_idle;
}
/* ----- Event dispatcher -------------------------------------------------- */
static void event(void)
{
uint8_t buf[MAX_PACKET];
struct timeval *to;
fd_set rset;
int res;
ssize_t got;
FD_ZERO(&rset);
FD_SET(net, &rset);
switch (state) {
case s_idle:
FD_SET(tun, &rset);
to = NULL;
break;
case s_rx:
to = timeout(T_REASS_MS);
break;
case s_tx:
to = timeout(T_ACK_MS);
break;
default:
abort();
}
res = select(net > tun ? net+1 : tun+1, &rset, NULL, NULL, to);
if (res < 0) {
perror("select");
return;
}
if (!res) {
switch (state) {
case s_rx:
reass_timeout();
break;
case s_tx:
ack_timeout();
break;
default:
abort();
}
}
if (FD_ISSET(tun, &rset)) {
got = read(tun, buf, sizeof(buf));
if (got < 0) {
perror("read tun");
return;
}
tx_pck(buf, got);
}
if (FD_ISSET(net, &rset)) {
got = read(net, buf, sizeof(buf));
if (got < 0) {
perror("read net");
return;
}
rx_pck(buf, got);
}
}
/* ----- Setup ------------------------------------------------------------- */
static int open_net(uint16_t pan, uint16_t me, uint16_t peer)
{
struct sockaddr_ieee802154 addr;
int s;
s = socket(PF_IEEE802154, SOCK_DGRAM, 0);
if (s < 0) {
perror("socket 802.15.4");
exit(1);
}
addr.family = AF_IEEE802154;
addr.addr.addr_type = IEEE802154_ADDR_SHORT;
addr.addr.pan_id = pan;
addr.addr.short_addr = me;
if (bind(s, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
perror("bind 802.15.4");
exit(1);
}
addr.addr.short_addr = peer;
if (connect(s, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
perror("connect 802.15.4");
exit(1);
}
return s;
}
static int open_tun(void)
{
struct ifreq ifr;
int fd;
fd = open(TUN_DEV, O_RDWR);
if (fd < 0) {
perror(TUN_DEV);
exit(1);
}
memset(&ifr, 0, sizeof(ifr));
ifr.ifr_flags = IFF_TUN | IFF_NO_PI;
if (ioctl(fd, TUNSETIFF, (void *) &ifr) < 0) {
perror("ioctl TUNSETIFF");
exit(1);
}
fprintf(stderr, "%s\n", ifr.ifr_name);
return fd;
}
/* ----- Command-line processing ------------------------------------------- */
static void usage(const char *name)
{
fprintf(stderr, "usage: %s [-d] pan_id src_addr dst_addr\n", name);
exit(1);
}
static uint16_t addr(const char *name, const char *s)
{
char *end;
unsigned long n;
n = strtoul(s, &end, 16);
if (*end)
usage(name);
if (n > 0xffff)
usage(name);
return n;
}
int main(int argc, char **argv)
{
uint16_t pan, src, dst;
int c;
while ((c = getopt(argc, argv, "d")) != EOF)
switch (c) {
case 'd':
debug++;
break;
default:
usage(*argv);
}
switch (argc-optind) {
case 3:
pan = addr(*argv, argv[optind]);
src = addr(*argv, argv[optind+1]);
dst = addr(*argv, argv[optind+2]);
break;
default:
usage(*argv);
}
net = open_net(pan, src, dst);
tun = open_tun();
while (1)
event();
return 0;
}