+/* vi: set sw=4 ts=4: */
/*
* RFC3927 ZeroConf IPv4 Link-Local addressing
* (see <http://www.zeroconf.org/>)
* Copyright (C) 2003 by Arthur van Hoff (avh@strangeberry.com)
* Copyright (C) 2004 by David Brownell
*
- * 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.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
- * 02111-1307 USA
+ * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
*/
/*
- * This can build as part of BusyBox or by itself:
- *
- * $(CROSS_COMPILE)cc -Os -Wall -DNO_BUSYBOX -DDEBUG -o zcip zcip.c
- *
* ZCIP just manages the 169.254.*.* addresses. That network is not
* routed at the IP level, though various proxies or bridges can
* certainly be used. Its naming is built over multicast DNS.
*/
-/* TODO:
- - more real-world usage/testing, especially daemon mode
- - kernel packet filters to reduce scheduling noise
- - avoid silent script failures, especially under load...
- - link status monitoring (restart on link-up; stop on link-down)
-*/
+// #define DEBUG
+
+// TODO:
+// - more real-world usage/testing, especially daemon mode
+// - kernel packet filters to reduce scheduling noise
+// - avoid silent script failures, especially under load...
+// - link status monitoring (restart on link-up; stop on link-down)
+
+#include "busybox.h"
#include <errno.h>
-#include <stdlib.h>
-#include <stdio.h>
#include <string.h>
#include <syslog.h>
#include <poll.h>
#include <time.h>
-#include <unistd.h>
-#include <sys/ioctl.h>
-#include <sys/types.h>
#include <sys/wait.h>
-#include <sys/time.h>
-#include <sys/socket.h>
-#include <arpa/inet.h>
-#include <netinet/in.h>
#include <netinet/ether.h>
#include <net/ethernet.h>
#include <net/if.h>
#include <linux/if_packet.h>
#include <linux/sockios.h>
-#include "busybox.h"
-#include "libbb.h"
+
struct arp_packet {
struct ether_header hdr;
- /* FIXME this part is netinet/if_ether.h "struct ether_arp" */
+ // FIXME this part is netinet/if_ether.h "struct ether_arp"
struct arphdr arp;
struct ether_addr source_addr;
struct in_addr source_ip;
struct ether_addr target_addr;
struct in_addr target_ip;
-} __attribute__ ((__packed__));
+} ATTRIBUTE_PACKED;
+enum {
/* 169.254.0.0 */
-static const uint32_t LINKLOCAL_ADDR = 0xa9fe0000;
+ LINKLOCAL_ADDR = 0xa9fe0000,
/* protocol timeout parameters, specified in seconds */
-static const unsigned PROBE_WAIT = 1;
-static const unsigned PROBE_MIN = 1;
-static const unsigned PROBE_MAX = 2;
-static const unsigned PROBE_NUM = 3;
-static const unsigned MAX_CONFLICTS = 10;
-static const unsigned RATE_LIMIT_INTERVAL = 60;
-static const unsigned ANNOUNCE_WAIT = 2;
-static const unsigned ANNOUNCE_NUM = 2;
-static const unsigned ANNOUNCE_INTERVAL = 2;
-static const time_t DEFEND_INTERVAL = 10;
-
-#define ZCIP_VERSION "0.75 (18 April 2005)"
+ PROBE_WAIT = 1,
+ PROBE_MIN = 1,
+ PROBE_MAX = 2,
+ PROBE_NUM = 3,
+ MAX_CONFLICTS = 10,
+ RATE_LIMIT_INTERVAL = 60,
+ ANNOUNCE_WAIT = 2,
+ ANNOUNCE_NUM = 2,
+ ANNOUNCE_INTERVAL = 2,
+ DEFEND_INTERVAL = 10
+};
static const struct in_addr null_ip = { 0 };
static const struct ether_addr null_addr = { {0, 0, 0, 0, 0, 0} };
+static int verbose = 0;
-/*
+#define DBG(fmt,args...) \
+ do { } while (0)
+#define VDBG DBG
+
+/**
* Pick a random link local IP address on 169.254/16, except that
* the first and last 256 addresses are reserved.
*/
-static void
-pick(struct in_addr *ip)
+static void pick(struct in_addr *ip)
{
unsigned tmp;
ip->s_addr = htonl((LINKLOCAL_ADDR + 0x0100) + tmp);
}
-/*
+/**
* Broadcast an ARP packet.
*/
-static int
-arp(int fd, struct sockaddr *saddr, int op,
+static int arp(int fd, struct sockaddr *saddr, int op,
const struct ether_addr *source_addr, struct in_addr source_ip,
const struct ether_addr *target_addr, struct in_addr target_ip)
{
struct arp_packet p;
- /* ether header */
+ // ether header
p.hdr.ether_type = htons(ETHERTYPE_ARP);
memcpy(p.hdr.ether_shost, source_addr, ETH_ALEN);
memset(p.hdr.ether_dhost, 0xff, ETH_ALEN);
- /* arp request */
+ // arp request
p.arp.ar_hrd = htons(ARPHRD_ETHER);
p.arp.ar_pro = htons(ETHERTYPE_IP);
p.arp.ar_hln = ETH_ALEN;
memcpy(&p.target_addr, target_addr, ETH_ALEN);
memcpy(&p.target_ip, &target_ip, sizeof (p.target_ip));
- /* send it */
+ // send it
if (sendto(fd, &p, sizeof (p), 0, saddr, sizeof (*saddr)) < 0) {
- bb_perror_msg("sendto");
+ perror("sendto");
return -errno;
}
return 0;
}
-/*
+/**
* Run a script.
*/
-static int
-run(char *script, char *arg, char *intf, struct in_addr *ip)
+static int run(char *script, char *arg, char *intf, struct in_addr *ip)
{
int pid, status;
char *why;
if (script != NULL) {
+ VDBG("%s run %s %s\n", intf, script, arg);
if (ip != NULL) {
char *addr = inet_ntoa(*ip);
- xsetenv("ip", addr);
+ setenv("ip", addr, 1);
syslog(LOG_INFO, "%s %s %s", arg, intf, addr);
}
pid = vfork();
- if (pid < 0) { /* error */
+ if (pid < 0) { // error
why = "vfork";
goto bad;
- } else if (pid == 0) { /* child */
+ } else if (pid == 0) { // child
execl(script, script, arg, NULL);
- bb_perror_msg_and_die("execl");
- }
+ perror("execl");
+ _exit(EXIT_FAILURE);
+ }
if (waitpid(pid, &status, 0) <= 0) {
why = "waitpid";
goto bad;
}
if (WEXITSTATUS(status) != 0) {
- bb_perror_msg("script %s failed, exit=%d", script, WEXITSTATUS(status));
+ bb_error_msg("script %s failed, exit=%d\n",
+ script, WEXITSTATUS(status));
return -errno;
}
}
return status;
}
-/*
+
+/**
* Return milliseconds of random delay, up to "secs" seconds.
*/
-static inline unsigned
-ms_rdelay(unsigned secs)
+static inline unsigned ms_rdelay(unsigned secs)
{
return lrand48() % (secs * 1000);
}
-/*
+/**
* main program
*/
-#define FOREGROUND 1
-#define QUIT 2
-#define REQUEST 4
-#define VERBOSE 8
-
int zcip_main(int argc, char *argv[])
{
char *intf = NULL;
char *script = NULL;
+ int quit = 0;
+ int foreground = 0;
+
char *why;
struct sockaddr saddr;
struct ether_addr addr;
struct in_addr ip = { 0 };
int fd;
int ready = 0;
- suseconds_t timeout = 0; /* milliseconds */
+ suseconds_t timeout = 0; // milliseconds
time_t defend = 0;
unsigned conflicts = 0;
unsigned nprobes = 0;
unsigned nclaims = 0;
- unsigned long t;
-
- bb_opt_complementaly = "vf";
- /* parse commandline: prog [options] ifname script */
- t = bb_getopt_ulflags(argc, argv, "fqr:v", &why); /* reuse char* why */
-
- argc -= optind;
- argv += optind;
-
- if ((t & 0x80000000UL) || (argc < 1) || (argc > 2)) {
- bb_show_usage();
- }
-
- if (t & VERBOSE) {
- bb_printf("%s: version %s\n", bb_applet_name, ZCIP_VERSION);
+ int t;
+
+ // parse commandline: prog [options] ifname script
+ while ((t = getopt(argc, argv, "fqr:v")) != EOF) {
+ switch (t) {
+ case 'f':
+ foreground = 1;
+ continue;
+ case 'q':
+ quit = 1;
+ continue;
+ case 'r':
+ if (inet_aton(optarg, &ip) == 0
+ || (ntohl(ip.s_addr) & IN_CLASSB_NET)
+ != LINKLOCAL_ADDR) {
+ bb_error_msg_and_die("invalid link address");
+ }
+ continue;
+ case 'v':
+ verbose++;
+ foreground = 1;
+ continue;
+ default:
+ bb_error_msg_and_die("bad option");
+ }
}
- if ((t & REQUEST) && (inet_aton(why, &ip) == 0 || (ntohl(ip.s_addr) & IN_CLASSB_NET) != LINKLOCAL_ADDR)) {
- bb_perror_msg_and_die("invalid link address");
+ if (optind < argc - 1) {
+ intf = argv[optind++];
+ setenv("interface", intf, 1);
+ script = argv[optind++];
}
-
- intf = argv[0];
- xsetenv("interface", intf);
- script = argv[1]; /* Could be NULL ? */
-
+ if (optind != argc || !intf)
+ bb_show_usage();
openlog(bb_applet_name, 0, LOG_DAEMON);
- /* initialize the interface (modprobe, ifup, etc) */
+ // initialize the interface (modprobe, ifup, etc)
if (run(script, "init", intf, NULL) < 0)
return EXIT_FAILURE;
- /* initialize saddr */
+ // initialize saddr
memset(&saddr, 0, sizeof (saddr));
- strncpy(saddr.sa_data, intf, sizeof (saddr.sa_data));
+ safe_strncpy(saddr.sa_data, intf, sizeof (saddr.sa_data));
- /* open an ARP socket */
+ // open an ARP socket
if ((fd = socket(PF_PACKET, SOCK_PACKET, htons(ETH_P_ARP))) < 0) {
why = "open";
fail:
- t |= FOREGROUND;
+ foreground = 1;
goto bad;
}
- /* bind to the interface's ARP socket */
+ // bind to the interface's ARP socket
if (bind(fd, &saddr, sizeof (saddr)) < 0) {
why = "bind";
goto fail;
} else {
struct ifreq ifr;
- short seed[3];
+ unsigned short seed[3];
- /* get the interface's ethernet address */
+ // get the interface's ethernet address
memset(&ifr, 0, sizeof (ifr));
strncpy(ifr.ifr_name, intf, sizeof (ifr.ifr_name));
if (ioctl(fd, SIOCGIFHWADDR, &ifr) < 0) {
}
memcpy(&addr, &ifr.ifr_hwaddr.sa_data, ETH_ALEN);
- /* start with some stable ip address, either a function of
- the hardware address or else the last address we used.
- NOTE: the sequence of addresses we try changes only
- depending on when we detect conflicts. */
+ // start with some stable ip address, either a function of
+ // the hardware address or else the last address we used.
+ // NOTE: the sequence of addresses we try changes only
+ // depending on when we detect conflicts.
memcpy(seed, &ifr.ifr_hwaddr.sa_data, ETH_ALEN);
seed48(seed);
if (ip.s_addr == 0)
pick(&ip);
}
- /* FIXME cases to handle:
- - zcip already running!
- - link already has local address... just defend/update */
+ // FIXME cases to handle:
+ // - zcip already running!
+ // - link already has local address... just defend/update
- /* daemonize now; don't delay system startup */
- if (!(t & FOREGROUND)) {
- if (daemon(0, (t & VERBOSE)) < 0) {
+ // daemonize now; don't delay system startup
+ if (!foreground) {
+ if (daemon(0, verbose) < 0) {
why = "daemon";
goto bad;
}
syslog(LOG_INFO, "start, interface %s", intf);
}
- /* run the dynamic address negotiation protocol,
- restarting after address conflicts:
- - start with some address we want to try
- - short random delay
- - arp probes to see if another host else uses it
- - arp announcements that we're claiming it
- - use it
- - defend it, within limits */
+ // run the dynamic address negotiation protocol,
+ // restarting after address conflicts:
+ // - start with some address we want to try
+ // - short random delay
+ // - arp probes to see if another host else uses it
+ // - arp announcements that we're claiming it
+ // - use it
+ // - defend it, within limits
while (1) {
struct pollfd fds[1];
struct timeval tv1;
fds[0].events = POLLIN;
fds[0].revents = 0;
- /* poll, being ready to adjust current timeout */
- if (timeout > 0) {
- gettimeofday(&tv1, NULL);
- tv1.tv_usec += (timeout % 1000) * 1000;
- while (tv1.tv_usec > 1000000) {
- tv1.tv_usec -= 1000000;
- tv1.tv_sec++;
- }
- tv1.tv_sec += timeout / 1000;
- } else if (timeout == 0) {
+ // poll, being ready to adjust current timeout
+ if (!timeout) {
timeout = ms_rdelay(PROBE_WAIT);
- /* FIXME setsockopt(fd, SO_ATTACH_FILTER, ...) to
- make the kernel filter out all packets except
- ones we'd care about. */
+ // FIXME setsockopt(fd, SO_ATTACH_FILTER, ...) to
+ // make the kernel filter out all packets except
+ // ones we'd care about.
}
+ gettimeofday(&tv1, NULL);
+ tv1.tv_usec += (timeout % 1000) * 1000;
+ while (tv1.tv_usec > 1000000) {
+ tv1.tv_usec -= 1000000;
+ tv1.tv_sec++;
+ }
+ tv1.tv_sec += timeout / 1000;
+
+ VDBG("...wait %ld %s nprobes=%d, nclaims=%d\n",
+ timeout, intf, nprobes, nclaims);
switch (poll(fds, 1, timeout)) {
- /* timeouts trigger protocol transitions */
+ // timeouts trigger protocol transitions
case 0:
- /* probes */
+ // probes
if (nprobes < PROBE_NUM) {
nprobes++;
+ VDBG("probe/%d %s@%s\n",
+ nprobes, intf, inet_ntoa(ip));
(void)arp(fd, &saddr, ARPOP_REQUEST,
&addr, null_ip,
&null_addr, ip);
} else
timeout = ANNOUNCE_WAIT * 1000;
}
- /* then announcements */
+ // then announcements
else if (nclaims < ANNOUNCE_NUM) {
nclaims++;
+ VDBG("announce/%d %s@%s\n",
+ nclaims, intf, inet_ntoa(ip));
(void)arp(fd, &saddr, ARPOP_REQUEST,
&addr, ip,
&addr, ip);
if (nclaims < ANNOUNCE_NUM) {
timeout = ANNOUNCE_INTERVAL * 1000;
} else {
- /* link is ok to use earlier */
+ // link is ok to use earlier
run(script, "config", intf, &ip);
ready = 1;
conflicts = 0;
timeout = -1;
- /* NOTE: all other exit paths
- should deconfig ... */
- if (t & QUIT)
+ // NOTE: all other exit paths
+ // should deconfig ...
+ if (quit)
return EXIT_SUCCESS;
- /* FIXME update filters */
+ // FIXME update filters
}
}
break;
- /* packets arriving */
+ // packets arriving
case 1:
- /* maybe adjust timeout */
+ // maybe adjust timeout
if (timeout > 0) {
struct timeval tv2;
-
+
gettimeofday(&tv2, NULL);
if (timercmp(&tv1, &tv2, <)) {
- timeout = -1;
+ timeout = 0;
} else {
timersub(&tv1, &tv2, &tv1);
timeout = 1000 * tv1.tv_sec
}
if ((fds[0].revents & POLLIN) == 0) {
if (fds[0].revents & POLLERR) {
- /* FIXME: links routinely go down;
- this shouldn't necessarily exit. */
- bb_perror_msg("%s: poll error", intf);
+ // FIXME: links routinely go down;
+ // this shouldn't necessarily exit.
+ bb_error_msg("%s: poll error\n", intf);
if (ready) {
- run(script, "deconfig", intf, &ip);
+ run(script, "deconfig",
+ intf, &ip);
}
return EXIT_FAILURE;
}
continue;
}
- /* read ARP packet */
+ // read ARP packet
if (recv(fd, &p, sizeof (p), 0) < 0) {
why = "recv";
goto bad;
}
if (p.hdr.ether_type != htons(ETHERTYPE_ARP))
continue;
-
+
+ VDBG("%s recv arp type=%d, op=%d,\n",
+ intf, ntohs(p.hdr.ether_type),
+ ntohs(p.arp.ar_op));
+ VDBG("\tsource=%s %s\n",
+ ether_ntoa(&p.source_addr),
+ inet_ntoa(p.source_ip));
+ VDBG("\ttarget=%s %s\n",
+ ether_ntoa(&p.target_addr),
+ inet_ntoa(p.target_ip));
if (p.arp.ar_op != htons(ARPOP_REQUEST)
&& p.arp.ar_op != htons(ARPOP_REPLY))
continue;
- /* some cases are always conflicts */
+ // some cases are always conflicts
if ((p.source_ip.s_addr == ip.s_addr)
&& (memcmp(&addr, &p.source_addr,
ETH_ALEN) != 0)) {
collision:
+ VDBG("%s ARP conflict from %s\n", intf,
+ ether_ntoa(&p.source_addr));
if (ready) {
time_t now = time(0);
ARPOP_REQUEST,
&addr, ip,
&addr, ip);
+ VDBG("%s defend\n", intf);
timeout = -1;
continue;
}
defend = now;
ready = 0;
run(script, "deconfig", intf, &ip);
- /* FIXME rm filters: setsockopt(fd,
- SO_DETACH_FILTER, ...) */
+ // FIXME rm filters: setsockopt(fd,
+ // SO_DETACH_FILTER, ...)
}
conflicts++;
if (conflicts >= MAX_CONFLICTS) {
+ VDBG("%s ratelimit\n", intf);
sleep(RATE_LIMIT_INTERVAL);
}
- /* restart the whole protocol */
+ // restart the whole protocol
pick(&ip);
timeout = 0;
nprobes = 0;
nclaims = 0;
}
- /* two hosts probing one address is a collision too */
+ // two hosts probing one address is a collision too
else if (p.target_ip.s_addr == ip.s_addr
&& nclaims == 0
&& p.arp.ar_op == htons(ARPOP_REQUEST)
}
}
bad:
- if ( t & FOREGROUND) {
- bb_perror_msg(why);
- } else {
+ if (foreground)
+ perror(why);
+ else
syslog(LOG_ERR, "%s %s, %s error: %s",
bb_applet_name, intf, why, strerror(errno));
- }
return EXIT_FAILURE;
}
projects / oweals / busybox.git / blobdiff