// - avoid silent script failures, especially under load...
// - link status monitoring (restart on link-up; stop on link-down)
-#include <syslog.h>
-#include <poll.h>
-#include <sys/wait.h>
#include <netinet/ether.h>
#include <net/ethernet.h>
#include <net/if.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)
+
/**
* Pick a random link local IP address on 169.254/16, except that
/**
* 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_sha, source_eth, 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_tha, target_eth, ETH_ALEN);
memcpy(&p.arp.arp_tpa, &target_ip, sizeof(p.arp.arp_tpa));
// send it
- xsendto(fd, &p, sizeof(p), saddr, sizeof(*saddr));
+ xsendto(sock_fd, &p, sizeof(p), &saddr, sizeof(saddr));
// Currently all callers ignore errors, that's why returns are
// commented out...
/**
* Run a script. argv[2] is already NULL.
*/
-static int run(char *argv[3], const char *intf, struct in_addr *ip)
+static int run(char *argv[3], struct in_addr *ip)
{
int status;
+ char *addr = addr; /* for gcc */
+ const char *fmt = "%s %s %s" + 3;
VDBG("%s run %s %s\n", intf, argv[0], argv[1]);
if (ip) {
- char *addr = inet_ntoa(*ip);
+ addr = inet_ntoa(*ip);
setenv("ip", addr, 1);
- bb_info_msg("%s %s %s", argv[1], intf, addr);
+ fmt -= 3;
}
+ bb_info_msg(fmt, argv[1], intf, addr);
status = wait4pid(spawn(argv));
if (status < 0) {
- bb_perror_msg("%s %s", argv[1], intf);
+ bb_perror_msg("%s %s %s" + 3, argv[1], intf);
return -errno;
}
if (status != 0)
/**
* Return milliseconds of random delay, up to "secs" seconds.
*/
-static unsigned ALWAYS_INLINE ms_rdelay(unsigned secs)
+static ALWAYS_INLINE unsigned random_delay_ms(unsigned secs)
{
return rand() % (secs * 1000);
}
/**
* main program
*/
-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;
- const char *why;
- int fd;
char *r_opt;
unsigned opts;
- /* Ugly trick, but I want these zeroed in one go */
+ // ugly trick, but I want these zeroed in one go
struct {
const struct in_addr null_ip;
const struct ether_addr null_addr;
- struct sockaddr saddr;
struct in_addr ip;
struct ifreq ifr;
- char *intf;
char *script_av[3];
int timeout_ms; /* must be signed */
unsigned conflicts;
} L;
#define null_ip (L.null_ip )
#define null_addr (L.null_addr )
-#define saddr (L.saddr )
#define ip (L.ip )
#define ifr (L.ifr )
-#define intf (L.intf )
#define script_av (L.script_av )
#define timeout_ms (L.timeout_ms)
#define conflicts (L.conflicts )
memset(&L, 0, sizeof(L));
- srand(MONOTONIC_US());
-
#define FOREGROUND (opts & 1)
#define QUIT (opts & 2)
// parse commandline: prog [options] ifname script
// exactly 2 args; -v accumulates and implies -f
opt_complementary = "=2:vv:vf";
- opts = getopt32(argc, argv, "fqr:v", &r_opt, &verbose);
+ 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 early, before all bb_xx_msg calls */
+ // do it before all bb_xx_msg calls
openlog(applet_name, 0, LOG_DAEMON);
logmode |= LOGMODE_SYSLOG;
}
bb_error_msg_and_die("invalid link address");
}
}
- // On NOMMU reexec early (or else we will rerun things twice)
-#if !BB_MMU
- if (!FOREGROUND)
- bb_daemonize_or_rexec(DAEMON_CHDIR_ROOT, argv);
-#endif
argc -= optind;
argv += optind;
// initialize the interface (modprobe, ifup, etc)
script_av[1] = (char*)"init";
- if (run(script_av, intf, NULL))
+ if (run(script_av, NULL))
return EXIT_FAILURE;
// initialize saddr
+ // 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");
- }
+ 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) {
#if BB_MMU
- bb_daemonize(DAEMON_CHDIR_ROOT);
+ bb_daemonize(0 /*was: DAEMON_CHDIR_ROOT*/);
#endif
bb_info_msg("start, interface %s", intf);
}
// 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
struct pollfd fds[1];
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_ms) {
- timeout_ms = ms_rdelay(PROBE_WAIT);
- // FIXME setsockopt(fd, SO_ATTACH_FILTER, ...) to
+ 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.
}
VDBG("...wait %d %s nprobes=%u, nclaims=%u\n",
timeout_ms, intf, nprobes, nclaims);
- switch (poll(fds, 1, timeout_ms)) {
+
+ switch (safe_poll(fds, 1, timeout_ms)) {
+
+ default:
+ //bb_perror_msg("poll"); - done in safe_poll
+ return EXIT_FAILURE;
// timeout
case 0:
nprobes++;
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_ms = PROBE_MIN * 1000;
- timeout_ms += ms_rdelay(PROBE_MAX - PROBE_MIN);
+ timeout_ms += random_delay_ms(PROBE_MAX - PROBE_MIN);
}
else {
// Switch to announce state.
nclaims = 0;
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_ms = ANNOUNCE_INTERVAL * 1000;
nclaims = 0;
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_ms = ANNOUNCE_INTERVAL * 1000;
nclaims++;
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_ms = ANNOUNCE_INTERVAL * 1000;
// link is ok to use earlier
// FIXME update filters
script_av[1] = (char*)"config";
- run(script_av, intf, &ip);
+ run(script_av, &ip);
ready = 1;
conflicts = 0;
timeout_ms = -1; // Never timeout in the monitor state.
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.
timeout_ms = 0;
} else {
VDBG("adjusting timeout\n");
- timeout_ms = diff / 1000;
- if (!timeout_ms) timeout_ms = 1;
+ 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) {
script_av[1] = (char*)"deconfig";
- run(script_av, intf, &ip);
+ 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("monitor conflict -- defending\n");
state = DEFEND;
timeout_ms = DEFEND_INTERVAL * 1000;
- arp(fd, &saddr,
- ARPOP_REQUEST,
- ð_addr, ip,
- ð_addr, ip);
+ arp(ARPOP_REQUEST,
+ ð_addr, ip,
+ ð_addr, ip);
}
break;
case DEFEND:
VDBG("defend conflict -- starting over\n");
ready = 0;
script_av[1] = (char*)"deconfig";
- run(script_av, intf, &ip);
+ run(script_av, &ip);
// restart the whole protocol
pick(&ip);
nclaims = 0;
break;
} // switch state
-
break; // case 1 (packets arriving)
- default:
- why = "poll";
- goto bad;
} // switch poll
- }
- bad:
- bb_perror_msg("%s, %s", intf, why);
- return EXIT_FAILURE;
+ } // while (1)
}
projects / oweals / busybox.git / blobdiff