// - 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 <string.h>
-#include <syslog.h>
-#include <poll.h>
-#include <time.h>
-
-#include <sys/wait.h>
-
#include <netinet/ether.h>
#include <net/ethernet.h>
#include <net/if.h>
#include <net/if_arp.h>
-
#include <linux/if_packet.h>
#include <linux/sockios.h>
+#include "libbb.h"
+#include <syslog.h>
+
+/* We don't need more than 32 bits of the counter */
+#define MONOTONIC_US() ((unsigned)monotonic_us())
struct arp_packet {
- struct ether_header hdr;
+ struct ether_header eth;
struct ether_arp arp;
} ATTRIBUTE_PACKED;
DEFEND
};
-#define VDBG(fmt,args...) \
- do { } while (0)
+#define VDBG(...) do { } while (0)
+
+
+enum {
+ sock_fd = 3
+};
+
+struct globals {
+ char *intf;
+ struct sockaddr saddr;
+};
+#define G (*(struct globals*)&bb_common_bufsiz1)
+#define intf (G.intf )
+#define saddr (G.saddr)
-static unsigned long opts;
-#define FOREGROUND (opts & 1)
-#define QUIT (opts & 2)
/**
* Pick a random link local IP address on 169.254/16, except that
{
unsigned tmp;
- /* use cheaper math than lrand48() mod N */
do {
- tmp = (lrand48() >> 16) & IN_CLASSB_HOST;
+ tmp = rand() & IN_CLASSB_HOST;
} while (tmp > (IN_CLASSB_HOST - 0x0200));
ip->s_addr = htonl((LINKLOCAL_ADDR + 0x0100) + tmp);
}
-/* TODO: we need a flag to direct bb_[p]error_msg output to stderr. */
-
/**
* Broadcast an ARP packet.
*/
-static void 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)
+static void arp(int op,
+ const struct ether_addr *source_eth, struct in_addr source_ip,
+ const struct ether_addr *target_eth, struct in_addr target_ip)
{
struct arp_packet p;
memset(&p, 0, sizeof(p));
// 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);
+ p.eth.ether_type = htons(ETHERTYPE_ARP);
+ memcpy(p.eth.ether_shost, source_eth, ETH_ALEN);
+ memset(p.eth.ether_dhost, 0xff, ETH_ALEN);
// arp request
p.arp.arp_hrd = htons(ARPHRD_ETHER);
p.arp.arp_hln = ETH_ALEN;
p.arp.arp_pln = 4;
p.arp.arp_op = htons(op);
- memcpy(&p.arp.arp_sha, source_addr, ETH_ALEN);
- memcpy(&p.arp.arp_spa, &source_ip, sizeof (p.arp.arp_spa));
- memcpy(&p.arp.arp_tha, target_addr, ETH_ALEN);
- memcpy(&p.arp.arp_tpa, &target_ip, sizeof (p.arp.arp_tpa));
+ memcpy(&p.arp.arp_sha, source_eth, ETH_ALEN);
+ memcpy(&p.arp.arp_spa, &source_ip, sizeof(p.arp.arp_spa));
+ memcpy(&p.arp.arp_tha, target_eth, ETH_ALEN);
+ memcpy(&p.arp.arp_tpa, &target_ip, sizeof(p.arp.arp_tpa));
// send it
- if (sendto(fd, &p, sizeof (p), 0, saddr, sizeof (*saddr)) < 0) {
- if (FOREGROUND)
- perror("sendto");
- else
- syslog(LOG_ERR, "sendto: %s", strerror(errno));
- //return -errno;
- }
+ xsendto(sock_fd, &p, sizeof(p), &saddr, sizeof(saddr));
+
// Currently all callers ignore errors, that's why returns are
// commented out...
//return 0;
}
/**
- * Run a script.
+ * Run a script. argv[2] is already NULL.
*/
-static int run(char *script, char *arg, char *intf, struct in_addr *ip)
+static int run(char *argv[3], struct in_addr *ip)
{
- int pid, status;
- char *why;
-
- if(1) { //always true: if (script != NULL)
- VDBG("%s run %s %s\n", intf, script, arg);
- if (ip != NULL) {
- char *addr = inet_ntoa(*ip);
- setenv("ip", addr, 1);
- if (!FOREGROUND)
- syslog(LOG_INFO, "%s %s %s", arg, intf, addr);
- }
+ int status;
+ char *addr = addr; /* for gcc */
+ const char *fmt = "%s %s %s" + 3;
- pid = vfork();
- if (pid < 0) { // error
- why = "vfork";
- goto bad;
- } else if (pid == 0) { // child
- execl(script, script, arg, NULL);
- if (FOREGROUND)
- perror("execl");
- else
- syslog(LOG_ERR, "execl: %s", strerror(errno));
- _exit(EXIT_FAILURE);
- }
+ VDBG("%s run %s %s\n", intf, argv[0], argv[1]);
- if (waitpid(pid, &status, 0) <= 0) {
- why = "waitpid";
- goto bad;
- }
- if (WEXITSTATUS(status) != 0) {
- if (FOREGROUND)
- bb_error_msg("script %s failed, exit=%d",
- script, WEXITSTATUS(status));
- else
- syslog(LOG_ERR, "script %s failed, exit=%d",
- script, WEXITSTATUS(status));
- return -errno;
- }
+ if (ip) {
+ addr = inet_ntoa(*ip);
+ setenv("ip", addr, 1);
+ fmt -= 3;
}
- return 0;
-bad:
- status = -errno;
- if (FOREGROUND)
- bb_perror_msg("%s %s, %s",
- arg, intf, why);
- else
- syslog(LOG_ERR, "%s %s, %s: %s",
- arg, intf, why, strerror(errno));
+ bb_info_msg(fmt, argv[1], intf, addr);
+
+ status = wait4pid(spawn(argv));
+ if (status < 0) {
+ bb_perror_msg("%s %s %s" + 3, argv[1], intf);
+ return -errno;
+ }
+ if (status != 0)
+ bb_error_msg("script %s %s failed, exitcode=%d", argv[0], argv[1], status);
return status;
}
-
/**
* Return milliseconds of random delay, up to "secs" seconds.
*/
-static unsigned ATTRIBUTE_ALWAYS_INLINE ms_rdelay(unsigned secs)
+static ALWAYS_INLINE unsigned random_delay_ms(unsigned secs)
{
- return lrand48() % (secs * 1000);
+ return rand() % (secs * 1000);
}
/**
* main program
*/
-
-/* Used to be auto variables on main() stack, but
- * most of them were zero-inited. Moving them to bss
- * is more space-efficient.
- */
-static const struct in_addr null_ip; // = { 0 };
-static const struct ether_addr null_addr; // = { {0, 0, 0, 0, 0, 0} };
-
-static struct sockaddr saddr; // memset(0);
-static struct in_addr ip; // = { 0 };
-static struct ifreq ifr; //memset(0);
-
-static char *intf; // = NULL;
-static char *script; // = NULL;
-static suseconds_t timeout; // = 0; // milliseconds
-static unsigned conflicts; // = 0;
-static unsigned nprobes; // = 0;
-static unsigned nclaims; // = 0;
-static int ready; // = 0;
-static int verbose; // = 0;
-static int state = PROBE;
-
-int zcip_main(int argc, char *argv[])
+int zcip_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int zcip_main(int argc, char **argv)
{
+ int state = PROBE;
struct ether_addr eth_addr;
- char *why;
- int fd;
+ char *r_opt;
+ unsigned opts;
+
+ // ugly trick, but I want these zeroed in one go
+ struct {
+ const struct in_addr null_ip;
+ const struct ether_addr null_addr;
+ struct in_addr ip;
+ struct ifreq ifr;
+ char *script_av[3];
+ int timeout_ms; /* must be signed */
+ unsigned conflicts;
+ unsigned nprobes;
+ unsigned nclaims;
+ int ready;
+ int verbose;
+ } L;
+#define null_ip (L.null_ip )
+#define null_addr (L.null_addr )
+#define ip (L.ip )
+#define ifr (L.ifr )
+#define script_av (L.script_av )
+#define timeout_ms (L.timeout_ms)
+#define conflicts (L.conflicts )
+#define nprobes (L.nprobes )
+#define nclaims (L.nclaims )
+#define ready (L.ready )
+#define verbose (L.verbose )
+
+ memset(&L, 0, sizeof(L));
+#define FOREGROUND (opts & 1)
+#define QUIT (opts & 2)
// parse commandline: prog [options] ifname script
- char *r_opt;
- bb_opt_complementally = "vv:vf"; // -v accumulates and implies -f
- opts = bb_getopt_ulflags(argc, argv, "fqr:v", &r_opt, &verbose);
+ // exactly 2 args; -v accumulates and implies -f
+ opt_complementary = "=2:vv:vf";
+ opts = getopt32(argv, "fqr:v", &r_opt, &verbose);
+#if !BB_MMU
+ // on NOMMU reexec early (or else we will rerun things twice)
+ if (!FOREGROUND)
+ bb_daemonize_or_rexec(0 /*was: DAEMON_CHDIR_ROOT*/, argv);
+#endif
+ // open an ARP socket
+ // (need to do it before openlog to prevent openlog from taking
+ // fd 3 (sock_fd==3))
+ xmove_fd(xsocket(AF_PACKET, SOCK_PACKET, htons(ETH_P_ARP)), sock_fd);
+ if (!FOREGROUND) {
+ // do it before all bb_xx_msg calls
+ openlog(applet_name, 0, LOG_DAEMON);
+ logmode |= LOGMODE_SYSLOG;
+ }
if (opts & 4) { // -r n.n.n.n
if (inet_aton(r_opt, &ip) == 0
- || (ntohl(ip.s_addr) & IN_CLASSB_NET) != LINKLOCAL_ADDR) {
+ || (ntohl(ip.s_addr) & IN_CLASSB_NET) != LINKLOCAL_ADDR
+ ) {
bb_error_msg_and_die("invalid link address");
}
}
argc -= optind;
argv += optind;
- if (argc != 2)
- bb_show_usage();
+
intf = argv[0];
- script = argv[1];
+ script_av[0] = argv[1];
setenv("interface", intf, 1);
// initialize the interface (modprobe, ifup, etc)
- if (run(script, "init", intf, NULL) < 0)
+ script_av[1] = (char*)"init";
+ if (run(script_av, NULL))
return EXIT_FAILURE;
// initialize saddr
- //memset(&saddr, 0, sizeof (saddr));
- safe_strncpy(saddr.sa_data, intf, sizeof (saddr.sa_data));
+ // saddr is: { u16 sa_family; u8 sa_data[14]; }
+ //memset(&saddr, 0, sizeof(saddr));
+ //TODO: are we leaving sa_family == 0 (AF_UNSPEC)?!
+ safe_strncpy(saddr.sa_data, intf, sizeof(saddr.sa_data));
- // open an ARP socket
- fd = xsocket(PF_PACKET, SOCK_PACKET, htons(ETH_P_ARP));
// bind to the interface's ARP socket
- xbind(fd, &saddr, sizeof (saddr));
+ xbind(sock_fd, &saddr, sizeof(saddr));
// 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) {
- bb_perror_msg_and_die("get ethernet address");
- }
+ //memset(&ifr, 0, sizeof(ifr));
+ strncpy(ifr.ifr_name, intf, sizeof(ifr.ifr_name));
+ xioctl(sock_fd, SIOCGIFHWADDR, &ifr);
memcpy(ð_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.
+ // we are taking low-order four bytes, as top-order ones
+ // aren't random enough.
// NOTE: the sequence of addresses we try changes only
// depending on when we detect conflicts.
- // (SVID 3 bogon: who says that "short" is always 16 bits?)
- seed48( (unsigned short*)&ifr.ifr_hwaddr.sa_data );
+ {
+ uint32_t t;
+ memcpy(&t, (char*)ð_addr + 2, 4);
+ srand(t);
+ }
if (ip.s_addr == 0)
pick(&ip);
// daemonize now; don't delay system startup
if (!FOREGROUND) {
- xdaemon(0, verbose);
- openlog(bb_applet_name, 0, LOG_DAEMON);
- syslog(LOG_INFO, "start, interface %s", intf);
+#if BB_MMU
+ bb_daemonize(0 /*was: DAEMON_CHDIR_ROOT*/);
+#endif
+ bb_info_msg("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 probes to see if another host uses it
// - arp announcements that we're claiming it
// - use it
// - defend it, within limits
while (1) {
struct pollfd fds[1];
- struct timeval tv1;
+ unsigned deadline_us;
struct arp_packet p;
+ int source_ip_conflict;
+ int target_ip_conflict;
- int source_ip_conflict = 0;
- int target_ip_conflict = 0;
-
- fds[0].fd = fd;
+ fds[0].fd = sock_fd;
fds[0].events = POLLIN;
fds[0].revents = 0;
// poll, being ready to adjust current timeout
- if (!timeout) {
- timeout = ms_rdelay(PROBE_WAIT);
- // FIXME setsockopt(fd, SO_ATTACH_FILTER, ...) to
+ if (!timeout_ms) {
+ timeout_ms = random_delay_ms(PROBE_WAIT);
+ // FIXME setsockopt(sock_fd, SO_ATTACH_FILTER, ...) to
// make the kernel filter out all packets except
// ones we'd care about.
}
- // set tv1 to the point in time when we timeout
- 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)) {
+ // set deadline_us to the point in time when we timeout
+ deadline_us = MONOTONIC_US() + timeout_ms * 1000;
+
+ VDBG("...wait %d %s nprobes=%u, nclaims=%u\n",
+ timeout_ms, intf, nprobes, nclaims);
+
+ switch (safe_poll(fds, 1, timeout_ms)) {
+
+ default:
+ //bb_perror_msg("poll"); - done in safe_poll
+ return EXIT_FAILURE;
// timeout
case 0:
// have been received, so we can progress through the states
if (nprobes < PROBE_NUM) {
nprobes++;
- VDBG("probe/%d %s@%s\n",
+ VDBG("probe/%u %s@%s\n",
nprobes, intf, inet_ntoa(ip));
- arp(fd, &saddr, ARPOP_REQUEST,
+ arp(ARPOP_REQUEST,
ð_addr, null_ip,
&null_addr, ip);
- timeout = PROBE_MIN * 1000;
- timeout += ms_rdelay(PROBE_MAX
- - PROBE_MIN);
+ timeout_ms = PROBE_MIN * 1000;
+ timeout_ms += random_delay_ms(PROBE_MAX - PROBE_MIN);
}
else {
// Switch to announce state.
state = ANNOUNCE;
nclaims = 0;
- VDBG("announce/%d %s@%s\n",
+ VDBG("announce/%u %s@%s\n",
nclaims, intf, inet_ntoa(ip));
- arp(fd, &saddr, ARPOP_REQUEST,
+ arp(ARPOP_REQUEST,
ð_addr, ip,
ð_addr, ip);
- timeout = ANNOUNCE_INTERVAL * 1000;
+ timeout_ms = ANNOUNCE_INTERVAL * 1000;
}
break;
case RATE_LIMIT_PROBE:
// have been received, so we can move immediately to the announce state
state = ANNOUNCE;
nclaims = 0;
- VDBG("announce/%d %s@%s\n",
+ VDBG("announce/%u %s@%s\n",
nclaims, intf, inet_ntoa(ip));
- arp(fd, &saddr, ARPOP_REQUEST,
+ arp(ARPOP_REQUEST,
ð_addr, ip,
ð_addr, ip);
- timeout = ANNOUNCE_INTERVAL * 1000;
+ timeout_ms = ANNOUNCE_INTERVAL * 1000;
break;
case ANNOUNCE:
// timeouts in the ANNOUNCE state mean no conflicting ARP packets
// have been received, so we can progress through the states
if (nclaims < ANNOUNCE_NUM) {
nclaims++;
- VDBG("announce/%d %s@%s\n",
+ VDBG("announce/%u %s@%s\n",
nclaims, intf, inet_ntoa(ip));
- arp(fd, &saddr, ARPOP_REQUEST,
+ arp(ARPOP_REQUEST,
ð_addr, ip,
ð_addr, ip);
- timeout = ANNOUNCE_INTERVAL * 1000;
+ timeout_ms = ANNOUNCE_INTERVAL * 1000;
}
else {
// Switch to monitor state.
state = MONITOR;
// link is ok to use earlier
// FIXME update filters
- run(script, "config", intf, &ip);
+ script_av[1] = (char*)"config";
+ run(script_av, &ip);
ready = 1;
conflicts = 0;
- timeout = -1; // Never timeout in the monitor state.
+ timeout_ms = -1; // Never timeout in the monitor state.
// NOTE: all other exit paths
// should deconfig ...
case DEFEND:
// We won! No ARP replies, so just go back to monitor.
state = MONITOR;
- timeout = -1;
+ timeout_ms = -1;
conflicts = 0;
break;
default:
// Invalid, should never happen. Restart the whole protocol.
state = PROBE;
pick(&ip);
- timeout = 0;
+ timeout_ms = 0;
nprobes = 0;
nclaims = 0;
break;
} // switch (state)
break; // case 0 (timeout)
- // packets arriving
+
+ // packets arriving, or link went down
case 1:
// We need to adjust the timeout in case we didn't receive
// a conflicting packet.
- if (timeout > 0) {
- struct timeval tv2;
-
- gettimeofday(&tv2, NULL);
- if (timercmp(&tv1, &tv2, <)) {
+ if (timeout_ms > 0) {
+ unsigned diff = deadline_us - MONOTONIC_US();
+ if ((int)(diff) < 0) {
// Current time is greater than the expected timeout time.
// Should never happen.
VDBG("missed an expected timeout\n");
- timeout = 0;
+ timeout_ms = 0;
} else {
VDBG("adjusting timeout\n");
- timersub(&tv1, &tv2, &tv1);
- timeout = 1000 * tv1.tv_sec
- + tv1.tv_usec / 1000;
+ timeout_ms = (diff / 1000) | 1; /* never 0 */
}
}
if (fds[0].revents & POLLERR) {
// FIXME: links routinely go down;
// this shouldn't necessarily exit.
- bb_error_msg("%s: poll error", intf);
+ bb_error_msg("iface %s is down", intf);
if (ready) {
- run(script, "deconfig",
- intf, &ip);
+ script_av[1] = (char*)"deconfig";
+ run(script_av, &ip);
}
return EXIT_FAILURE;
}
}
// read ARP packet
- if (recv(fd, &p, sizeof (p), 0) < 0) {
- why = "recv";
- goto bad;
+ if (safe_read(sock_fd, &p, sizeof(p)) < 0) {
+ bb_perror_msg_and_die(bb_msg_read_error);
}
- if (p.hdr.ether_type != htons(ETHERTYPE_ARP))
+ if (p.eth.ether_type != htons(ETHERTYPE_ARP))
continue;
-
#ifdef DEBUG
{
- struct ether_addr * sha = (struct ether_addr *) p.arp.arp_sha;
- struct ether_addr * tha = (struct ether_addr *) p.arp.arp_tha;
- struct in_addr * spa = (struct in_addr *) p.arp.arp_spa;
- struct in_addr * tpa = (struct in_addr *) p.arp.arp_tpa;
+ struct ether_addr *sha = (struct ether_addr *) p.arp.arp_sha;
+ struct ether_addr *tha = (struct ether_addr *) p.arp.arp_tha;
+ struct in_addr *spa = (struct in_addr *) p.arp.arp_spa;
+ struct in_addr *tpa = (struct in_addr *) p.arp.arp_tpa;
VDBG("%s recv arp type=%d, op=%d,\n",
- intf, ntohs(p.hdr.ether_type),
+ intf, ntohs(p.eth.ether_type),
ntohs(p.arp.arp_op));
VDBG("\tsource=%s %s\n",
ether_ntoa(sha),
}
#endif
if (p.arp.arp_op != htons(ARPOP_REQUEST)
- && p.arp.arp_op != htons(ARPOP_REPLY))
+ && p.arp.arp_op != htons(ARPOP_REPLY))
continue;
- if (memcmp(p.arp.arp_spa, &ip.s_addr, sizeof(struct in_addr)) == 0 &&
- memcmp(ð_addr, &p.arp.arp_sha, ETH_ALEN) != 0) {
+ source_ip_conflict = 0;
+ target_ip_conflict = 0;
+
+ if (memcmp(p.arp.arp_spa, &ip.s_addr, sizeof(struct in_addr)) == 0
+ && memcmp(&p.arp.arp_sha, ð_addr, ETH_ALEN) != 0
+ ) {
source_ip_conflict = 1;
}
- if (memcmp(p.arp.arp_tpa, &ip.s_addr, sizeof(struct in_addr)) == 0 &&
- p.arp.arp_op == htons(ARPOP_REQUEST) &&
- memcmp(ð_addr, &p.arp.arp_tha, ETH_ALEN) != 0) {
+ if (p.arp.arp_op == htons(ARPOP_REQUEST)
+ && memcmp(p.arp.arp_tpa, &ip.s_addr, sizeof(struct in_addr)) == 0
+ && memcmp(&p.arp.arp_tha, ð_addr, ETH_ALEN) != 0
+ ) {
target_ip_conflict = 1;
}
- VDBG("state = %d, source ip conflict = %d, target ip conflict = %d\n",
+ VDBG("state = %d, source ip conflict = %d, target ip conflict = %d\n",
state, source_ip_conflict, target_ip_conflict);
switch (state) {
case PROBE:
conflicts++;
if (conflicts >= MAX_CONFLICTS) {
VDBG("%s ratelimit\n", intf);
- timeout = RATE_LIMIT_INTERVAL * 1000;
+ timeout_ms = RATE_LIMIT_INTERVAL * 1000;
state = RATE_LIMIT_PROBE;
}
// restart the whole protocol
pick(&ip);
- timeout = 0;
+ timeout_ms = 0;
nprobes = 0;
nclaims = 0;
}
if (source_ip_conflict) {
VDBG("monitor conflict -- defending\n");
state = DEFEND;
- timeout = DEFEND_INTERVAL * 1000;
- arp(fd, &saddr,
- ARPOP_REQUEST,
- ð_addr, ip,
- ð_addr, ip);
+ timeout_ms = DEFEND_INTERVAL * 1000;
+ arp(ARPOP_REQUEST,
+ ð_addr, ip,
+ ð_addr, ip);
}
break;
case DEFEND:
state = PROBE;
VDBG("defend conflict -- starting over\n");
ready = 0;
- run(script, "deconfig", intf, &ip);
+ script_av[1] = (char*)"deconfig";
+ run(script_av, &ip);
// restart the whole protocol
pick(&ip);
- timeout = 0;
+ timeout_ms = 0;
nprobes = 0;
nclaims = 0;
}
VDBG("invalid state -- starting over\n");
state = PROBE;
pick(&ip);
- timeout = 0;
+ timeout_ms = 0;
nprobes = 0;
nclaims = 0;
break;
} // switch state
-
break; // case 1 (packets arriving)
- default:
- why = "poll";
- goto bad;
} // switch poll
- }
-bad:
- if (FOREGROUND)
- perror(why);
- else
- syslog(LOG_ERR, "%s %s, %s error: %s",
- bb_applet_name, intf, why, strerror(errno));
- return EXIT_FAILURE;
+ } // while (1)
}
projects / oweals / busybox.git / blobdiff