minix3/commands/rarpd/rarpd.c

369 lines
9.0 KiB
C

/*
rarpd.c
Created: Nov 12, 1992 by Philip Homburg
Changed: May 13, 1995 by Kees J. Bot
Rewrite to handle multiple ethernets.
Changed: Jul 18, 1995 by Kees J. Bot
Do RARP requests (formerly inet's job)
Changed: Dec 14, 1996 by Kees J. Bot
Query the netmask
Changed: Dec 11, 2000 by Kees J. Bot
Dressed down to be only a RARP server, giving the floor to DHCP
*/
#include <sys/types.h>
#include <sys/ioctl.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <string.h>
#include <unistd.h>
#include <sys/asynchio.h>
#include <net/hton.h>
#include <net/gen/socket.h>
#include <netdb.h>
#include <net/gen/in.h>
#include <net/gen/inet.h>
#include <net/gen/ether.h>
#include <net/gen/eth_io.h>
#include <net/gen/if_ether.h>
#include <net/gen/ip_io.h>
#include <arpa/nameser.h>
#define MAX_RARP_RETRIES 5
#define RARP_TIMEOUT 5
#undef HTONS
#define HTONS htons
typedef struct rarp46
{
ether_addr_t a46_dstaddr;
ether_addr_t a46_srcaddr;
ether_type_t a46_ethtype;
u16_t a46_hdr, a46_pro;
u8_t a46_hln, a46_pln;
u16_t a46_op;
ether_addr_t a46_sha;
u8_t a46_spa[4];
ether_addr_t a46_tha;
u8_t a46_tpa[4];
char a46_padding[ETH_MIN_PACK_SIZE - (4*6 + 2*4 + 4*2 + 2*1)];
} rarp46_t;
#define ETH_RARP_PROTO 0x8035
#define RARP_ETHERNET 1
#define RARP_REQUEST 3
#define RARP_REPLY 4
static char *program;
static unsigned debug;
#define between(a, c, z) ((unsigned) (c) - (a) <= (unsigned) (z) - (a))
static void report(const char *label)
{
fprintf(stderr, "%s: %s: %s\n", program, label, strerror(errno));
}
static void fatal(const char *label)
{
report(label);
exit(1);
}
static void *allocate(size_t size)
{
void *mem;
if ((mem= malloc(size)) == NULL) fatal("Can't allocate memory");
return mem;
}
static char *ethdev(int n)
{
static char an_ethdev[]= "/dev/ethNNN";
sprintf(an_ethdev + sizeof(an_ethdev)-4, "%d", n);
return an_ethdev;
}
static char *ipdev(int n)
{
static char an_ipdev[]= "/dev/ipNNN";
sprintf(an_ipdev + sizeof(an_ipdev)-4, "%d", n);
return an_ipdev;
}
typedef struct ethernet {
int n; /* Network number. */
int eth_fd; /* Open low level ethernet device. */
ether_addr_t eth_addr; /* Ethernet address of this net. */
char packet[ETH_MAX_PACK_SIZE]; /* Incoming packet. */
ipaddr_t ip_addr; /* IP address of this net. */
ipaddr_t ip_mask; /* Associated netmask. */
} ethernet_t;
static ethernet_t *ethernets;
static void onsig(int sig)
{
switch (sig) {
case SIGUSR1: debug++; break;
case SIGUSR2: debug= 0; break;
}
}
static void rarp_reply(ethernet_t *ep, char *hostname, ipaddr_t ip_addr,
ether_addr_t eth_addr)
{
rarp46_t rarp46;
/* Construct a RARP reply packet and send it. */
rarp46.a46_dstaddr= eth_addr;
rarp46.a46_hdr= HTONS(RARP_ETHERNET);
rarp46.a46_pro= HTONS(ETH_IP_PROTO);
rarp46.a46_hln= 6;
rarp46.a46_pln= 4;
rarp46.a46_op= HTONS(RARP_REPLY);
rarp46.a46_sha= ep->eth_addr;
memcpy(rarp46.a46_spa, &ep->ip_addr, sizeof(ipaddr_t));
rarp46.a46_tha= eth_addr;
memcpy(rarp46.a46_tpa, &ip_addr, sizeof(ipaddr_t));
if (debug >= 1) {
printf("%s: Replying %s (%s) to %s\n",
ethdev(ep->n), inet_ntoa(ip_addr), hostname, ether_ntoa(&eth_addr));
}
(void) write(ep->eth_fd, &rarp46, sizeof(rarp46));
}
static int addhostname(char *addname, char *hostname, int n)
{
/* Create an additional hostname for a given hostname by adding "-n" to
* the first part. E.g. given "wombat.cs.vu.nl" and n=2 return
* "wombat-2.cs.vu.nl". This is useful for VU practical work where
* people get a few extra ethernet addresses on a machine and are asked
* to build a TCP/IP stack on it.
*/
char *dot;
if (strlen(hostname) + 4 >= 1024) return 0;
if ((dot= strchr(hostname, '.')) == NULL) dot= strchr(hostname, 0);
sprintf(addname, "%.*s-%d%s", (dot - hostname), hostname, n, dot);
return 1;
}
static void usage(void)
{
fprintf(stderr, "Usage: %s [-d[level]] network-name ...\n", program);
exit(1);
}
static int ifname2n(const char *name)
{
/* Translate an interface name, ip0, ip1, etc, to a number. */
const char *np;
char *end;
unsigned long n;
np= name;
if (*np++ != 'i' || *np++ != 'p') usage();
n= strtoul(np, &end, 10);
if (end == np || *end != 0) usage();
if (n >= 1000) {
fprintf(stderr, "%s: Network number of \"%s\" is a bit large\n",
program, name);
exit(1);
}
return n;
}
int main(int argc, char **argv)
{
int i;
ethernet_t *ep;
nwio_ethopt_t ethopt;
nwio_ethstat_t ethstat;
char hostname[1024];
struct hostent *hostent;
struct sigaction sa;
nwio_ipconf_t ipconf;
asynchio_t asyn;
ssize_t n;
ipaddr_t ip_addr;
rarp46_t rarp46;
int fd;
int n_eths;
program= argv[0];
asyn_init(&asyn);
debug= 0;
i= 1;
while (i < argc && argv[i][0] == '-') {
char *opt= argv[i++]+1;
if (opt[0] == '-' && opt[1] == 0) break; /* -- */
while (*opt != 0) switch (*opt++) {
case 'd':
debug= 1;
if (between('0', *opt, '9')) debug= strtoul(opt, &opt, 10);
break;
default:
usage();
}
}
if ((n_eths= (argc - i)) == 0) usage();
#if __minix_vmd
/* Minix-vmd can handle all nets at once using async I/O. */
ethernets= allocate(n_eths * sizeof(ethernets[0]));
for (i= 0; i < n_eths; i++) {
ethernets[i].n= ifname2n(argv[argc - n_eths + i]);
}
#else
/* Minix forks n-1 times to handle each net in a process each. */
for (i= 0; i < n_eths; i++) {
if (i+1 < n_eths) {
switch (fork()) {
case -1: fatal("fork()");
case 0: break;
default: continue;
}
}
ethernets= allocate(1 * sizeof(ethernets[0]));
ethernets[0].n= ifname2n(argv[argc - n_eths + i]);
}
n_eths= 1;
#endif
sa.sa_handler= onsig;
sigemptyset(&sa.sa_mask);
sa.sa_flags= 0;
sigaction(SIGUSR1, &sa, NULL);
sigaction(SIGUSR2, &sa, NULL);
for (i= 0; i < n_eths; i++) {
ep= &ethernets[i];
if ((ep->eth_fd= open(ethdev(ep->n), O_RDWR)) < 0) fatal(ethdev(ep->n));
if (ioctl(ep->eth_fd, NWIOGETHSTAT, &ethstat) < 0) {
fprintf(stderr, "%s: %s: Unable to get eth statistics: %s\n",
program, ethdev(ep->n), strerror(errno));
exit(1);
}
ep->eth_addr= ethstat.nwes_addr;
if (debug >= 1) {
printf("%s: Ethernet address is %s\n",
ethdev(ep->n), ether_ntoa(&ep->eth_addr));
}
ethopt.nweo_flags= NWEO_COPY | NWEO_EN_LOC | NWEO_EN_BROAD |
NWEO_TYPESPEC;
ethopt.nweo_type= HTONS(ETH_RARP_PROTO);
if (ioctl(ep->eth_fd, NWIOSETHOPT, &ethopt) < 0) {
fprintf(stderr, "%s: %s: Unable to set eth options: %s\n",
program, ethdev(ep->n), strerror(errno));
exit(1);
}
/* What are my address and netmask? */
if ((fd= open(ipdev(ep->n), O_RDWR)) < 0) fatal(ipdev(ep->n));
if (ioctl(fd, NWIOGIPCONF, &ipconf) < 0) fatal(ipdev(ep->n));
ep->ip_addr= ipconf.nwic_ipaddr;
ep->ip_mask= ipconf.nwic_netmask;
close(fd);
if (debug >= 1) {
printf("%s: IP address is %s / ",
ipdev(ep->n), inet_ntoa(ep->ip_addr));
printf("%s\n", inet_ntoa(ep->ip_mask));
}
}
/* Wait for RARP requests, reply, repeat. */
for(;;) {
fflush(NULL);
/* Wait for a RARP request. */
for (i= 0; i < n_eths; i++) {
ep= &ethernets[i];
n= asyn_read(&asyn, ep->eth_fd, ep->packet, sizeof(ep->packet));
if (n != -1) break;
if (errno != EINPROGRESS) {
report(ethdev(ep->n));
sleep(10);
}
}
/* RARP request? */
if (i < n_eths
&& n >= sizeof(rarp46)
&& (memcpy(&rarp46, ep->packet, sizeof(rarp46)), 1)
&& rarp46.a46_hdr == HTONS(RARP_ETHERNET)
&& rarp46.a46_pro == HTONS(ETH_IP_PROTO)
&& rarp46.a46_hln == 6
&& rarp46.a46_pln == 4
&& rarp46.a46_op == HTONS(RARP_REQUEST)
) {
if ((ether_ntohost(hostname, &rarp46.a46_tha) == 0
|| (rarp46.a46_tha.ea_addr[0] == 'v'
&& (memcpy(&ip_addr, rarp46.a46_tha.ea_addr+2, 4), 1)
&& (hostent= gethostbyaddr((char*) &ip_addr,
4, AF_INET)) != NULL
&& addhostname(hostname, hostent->h_name,
rarp46.a46_tha.ea_addr[1])))
&& (hostent= gethostbyname(hostname)) != NULL
&& hostent->h_addrtype == AF_INET
) {
/* Host is found in the ethers file and the DNS, or the
* ethernet address denotes a special additional address
* used for implementing a TCP/IP stack in user space.
*/
for (i= 0; hostent->h_addr_list[i] != NULL; i++) {
memcpy(&ip_addr, hostent->h_addr_list[i], sizeof(ipaddr_t));
/* Check if the address is on this network. */
if (((ip_addr ^ ep->ip_addr) & ep->ip_mask) == 0) break;
}
if (hostent->h_addr_list[i] != NULL) {
rarp_reply(ep, hostname, ip_addr, rarp46.a46_tha);
} else {
if (debug >= 2) {
printf("%s: Host '%s' (%s) is on the wrong net\n",
ethdev(ep->n),
hostname, ether_ntoa(&rarp46.a46_tha));
}
}
} else {
if (debug >= 2) {
printf("%s: RARP request from unknown host '%s'\n",
ethdev(ep->n), ether_ntoa(&rarp46.a46_tha));
}
}
}
/* Wait for another request. */
if (asyn_wait(&asyn, 0, NULL) < 0) {
report("asyn_wait()");
sleep(10);
}
}
}