main.c

klibc精简化的c程序库

#include <errno.h>
#include <poll.h>
#include <limits.h>
#include <setjmp.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <time.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/time.h>
#include <dirent.h>
#include <fcntl.h>
#include <unistd.h>		/* for getopts */

#include <net/if_arp.h>

#include "ipconfig.h"
#include "netdev.h"
#include "bootp_packet.h"
#include "bootp_proto.h"
#include "dhcp_proto.h"
#include "packet.h"

static const char sysfs_class_net[] = "/sys/class/net";
static const char *progname;
static jmp_buf abort_buf;
static char do_not_config;
static unsigned int default_caps = CAP_DHCP | CAP_BOOTP | CAP_RARP;
static int loop_timeout = -1;
static int configured;
static int bringup_first = 0;

/* DHCP vendor class identifier */
char vendor_class_identifier[260];
int vendor_class_identifier_len;

struct state {
	int state;
	int restart_state;
	time_t expire;
	int retry_period;

	struct netdev *dev;
	struct state *next;
};

static inline const char *my_inet_ntoa(uint32_t addr)
{
	struct in_addr a;

	a.s_addr = addr;

	return inet_ntoa(a);
}

static void print_device_config(struct netdev *dev)
{
	printf("IP-Config: %s complete (from %s):\n", dev->name,
	       my_inet_ntoa(dev->serverid ? dev->serverid : dev->ip_server));
	printf(" address: %-16s ", my_inet_ntoa(dev->ip_addr));
	printf("broadcast: %-16s ", my_inet_ntoa(dev->ip_broadcast));
	printf("netmask: %-16s\n", my_inet_ntoa(dev->ip_netmask));
	printf(" gateway: %-16s ", my_inet_ntoa(dev->ip_gateway));
	printf("dns0     : %-16s ", my_inet_ntoa(dev->ip_nameserver[0]));
	printf("dns1   : %-16s\n", my_inet_ntoa(dev->ip_nameserver[1]));
	if (dev->hostname[0])
		printf(" host   : %-64s\n", dev->hostname);
	if (dev->dnsdomainname[0])
		printf(" domain : %-64s\n", dev->dnsdomainname);
	if (dev->nisdomainname[0])
		printf(" nisdomain: %-64s\n", dev->nisdomainname);
	printf(" rootserver: %s ", my_inet_ntoa(dev->ip_server));
	printf("rootpath: %s\n", dev->bootpath);
	printf(" filename  : %s\n", dev->filename);
}

static void configure_device(struct netdev *dev)
{
	if (do_not_config)
		return;

	if (netdev_setmtu(dev))
		printf("IP-Config: failed to set MTU on %s to %u\n",
		       dev->name, dev->mtu);

	if (netdev_setaddress(dev))
		printf("IP-Config: failed to set addresses on %s\n", dev->name);
	if (netdev_setdefaultroute(dev))
		printf("IP-Config: failed to set default route on %s\n",
		       dev->name);
	if (dev->hostname[0] &&
			sethostname(dev->hostname, strlen(dev->hostname)))
		printf("IP-Config: failed to set hostname '%s' from %s\n",
			dev->hostname, dev->name);
}

static void dump_device_config(struct netdev *dev)
{
	char fn[40];
	FILE *f;

	snprintf(fn, sizeof(fn), "/tmp/net-%s.conf", dev->name);
	f = fopen(fn, "w");
	if (f) {
		fprintf(f, "DEVICE=%s\n", dev->name);
		fprintf(f, "IPV4ADDR=%s\n", my_inet_ntoa(dev->ip_addr));
		fprintf(f, "IPV4BROADCAST=%s\n",
			my_inet_ntoa(dev->ip_broadcast));
		fprintf(f, "IPV4NETMASK=%s\n", my_inet_ntoa(dev->ip_netmask));
		fprintf(f, "IPV4GATEWAY=%s\n", my_inet_ntoa(dev->ip_gateway));
		fprintf(f, "IPV4DNS0=%s\n",
			my_inet_ntoa(dev->ip_nameserver[0]));
		fprintf(f, "IPV4DNS1=%s\n",
			my_inet_ntoa(dev->ip_nameserver[1]));
		fprintf(f, "HOSTNAME=%s\n", dev->hostname);
		fprintf(f, "DNSDOMAIN=%s\n", dev->dnsdomainname);
		fprintf(f, "NISDOMAIN=%s\n", dev->nisdomainname);
		fprintf(f, "ROOTSERVER=%s\n", my_inet_ntoa(dev->ip_server));
		fprintf(f, "ROOTPATH=%s\n", dev->bootpath);
		fprintf(f, "filename=\"%s\"\n", dev->filename);
		fclose(f);
	}
}

static uint32_t inet_class_netmask(uint32_t ip)
{
	ip = ntohl(ip);
	if (IN_CLASSA(ip))
		return htonl(IN_CLASSA_NET);
	if (IN_CLASSB(ip))
		return htonl(IN_CLASSB_NET);
	if (IN_CLASSC(ip))
		return htonl(IN_CLASSC_NET);
	return INADDR_ANY;
}

static void postprocess_device(struct netdev *dev)
{
	if (dev->ip_netmask == INADDR_ANY) {
		dev->ip_netmask = inet_class_netmask(dev->ip_addr);
		printf("IP-Config: %s guessed netmask %s\n",
		       dev->name, my_inet_ntoa(dev->ip_netmask));
	}
	if (dev->ip_broadcast == INADDR_ANY) {
		dev->ip_broadcast =
		    (dev->ip_addr & dev->ip_netmask) | ~dev->ip_netmask;
		printf("IP-Config: %s guessed broadcast address %s\n",
		       dev->name, my_inet_ntoa(dev->ip_broadcast));
	}
	if (dev->ip_nameserver[0] == INADDR_ANY) {
		dev->ip_nameserver[0] = dev->ip_server;
		printf("IP-Config: %s guessed nameserver address %s\n",
		       dev->name, my_inet_ntoa(dev->ip_nameserver[0]));
	}
}

static void complete_device(struct netdev *dev)
{
	postprocess_device(dev);
	configure_device(dev);
	dump_device_config(dev);
	print_device_config(dev);

	++configured;

	dev->next = ifaces;
	ifaces = dev;
}

static int process_receive_event(struct state *s, time_t now)
{
	int handled = 1;

	switch (s->state) {
	case DEVST_BOOTP:
		s->restart_state = DEVST_BOOTP;
		switch (bootp_recv_reply(s->dev)) {
		case -1:
			s->state = DEVST_ERROR;
			break;
		case 1:
			s->state = DEVST_COMPLETE;
			DEBUG(("\n   bootp reply\n"));
			break;
		}
		break;

	case DEVST_DHCPDISC:
		s->restart_state = DEVST_DHCPDISC;
		switch (dhcp_recv_offer(s->dev)) {
		case -1:
			s->state = DEVST_ERROR;
			break;
		case 1:	/* Offer received */
			s->state = DEVST_DHCPREQ;
			dhcp_send_request(s->dev);
			break;
		}
		break;

	case DEVST_DHCPREQ:
		s->restart_state = DEVST_DHCPDISC;
		switch (dhcp_recv_ack(s->dev)) {
		case -1:	/* error */
			s->state = DEVST_ERROR;
			break;
		case 1:	/* ACK received */
			s->state = DEVST_COMPLETE;
			break;
		case 2:	/* NAK received */
			s->state = DEVST_DHCPDISC;
			break;
		}
		break;
	}

	switch (s->state) {
	case DEVST_COMPLETE:
		complete_device(s->dev);
		break;

	case DEVST_ERROR:
		/* error occurred, try again in 10 seconds */
		s->expire = now + 10;
	default:
		DEBUG(("\n"));
		handled = 0;
		break;
	}

	return handled;
}

static void process_timeout_event(struct state *s, time_t now)
{
	int ret = 0;

	/*
	 * Is the link up?  If not, try again in 1 second.
	 */
	if (!netdev_running(s->dev)) {
		s->expire = now + 1;
		s->state = s->restart_state;
		return;
	}

	/*
	 * If we had an error, restore a sane state to
	 * restart from.
	 */
	if (s->state == DEVST_ERROR)
		s->state = s->restart_state;

	/*
	 * Now send a packet depending on our state.
	 */
	switch (s->state) {
	case DEVST_BOOTP:
		ret = bootp_send_request(s->dev);
		s->restart_state = DEVST_BOOTP;
		break;

	case DEVST_DHCPDISC:
		ret = dhcp_send_discover(s->dev);
		s->restart_state = DEVST_DHCPDISC;
		break;

	case DEVST_DHCPREQ:
		ret = dhcp_send_request(s->dev);
		s->restart_state = DEVST_DHCPDISC;
		break;
	}

	if (ret == -1) {
		s->state = DEVST_ERROR;
		s->expire = now + 10;
	} else {
		s->expire = now + s->retry_period;

		s->retry_period *= 2;
		if (s->retry_period > 60)
			s->retry_period = 60;
	}
}

static struct state *slist;
struct netdev *ifaces;

static int do_pkt_recv(int pkt_fd, time_t now)
{
	int ifindex, ret;
	struct state *s;

	ret = packet_peek(&ifindex);
	if (ret < 0)
		goto bail;

	for (s = slist; s; s = s->next) {
		if (s->dev->ifindex == ifindex) {
			ret |= process_receive_event(s, now);
			break;
		}
	}

      bail:
	return ret;
}

static int loop(void)
{
#define NR_FDS	1
	struct pollfd fds[NR_FDS];
	struct state *s;
	int pkt_fd;
	int nr = 0;
	struct timeval now, prev;
	time_t start;

	pkt_fd = packet_open();
	if (pkt_fd == -1) {
		perror("packet_open");
		return -1;
	}

	fds[0].fd = pkt_fd;
	fds[0].events = POLLRDNORM;

	gettimeofday(&now, NULL);
	start = now.tv_sec;
	while (1) {
		int timeout = 60;
		int pending = 0;
		int done = 0;
		int timeout_ms;
		int x;

		for (s = slist; s; s = s->next) {
			DEBUG(("%s: state = %d\n", s->dev->name, s->state));

			if (s->state == DEVST_COMPLETE) {
				done++;
				continue;
			}

			pending++;

			if (s->expire - now.tv_sec <= 0) {
				DEBUG(("timeout\n"));
				process_timeout_event(s, now.tv_sec);
			}

			if (timeout > s->expire - now.tv_sec)
				timeout = s->expire - now.tv_sec;
		}

		if (pending == 0 || (bringup_first && done))
			break;

		timeout_ms = timeout * 1000;

		for (x = 0; x < 2; x++) {
			int delta_ms;

			if (timeout_ms <= 0)
				timeout_ms = 100;

			nr = poll(fds, NR_FDS, timeout_ms);
			prev = now;
			gettimeofday(&now, NULL);

			if ((fds[0].revents & POLLRDNORM)) {
				nr = do_pkt_recv(pkt_fd, now.tv_sec);
				if (nr == 1)
					break;
				else if (nr == 0)
					packet_discard();
			}

			if (loop_timeout >= 0 &&
			    now.tv_sec - start >= loop_timeout) {
				printf("IP-Config: no response after %d "
				       "secs - giving up\n", loop_timeout);
				goto bail;
			}

			delta_ms = (now.tv_sec - prev.tv_sec) * 1000;
			delta_ms += (now.tv_usec - prev.tv_usec) / 1000;

			DEBUG(("Delta: %d ms\n", delta_ms));

			timeout_ms -= delta_ms;
		}
	}