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-rw-r--r--networking/zcip.c295
1 files changed, 186 insertions, 109 deletions
diff --git a/networking/zcip.c b/networking/zcip.c
index de9ea76..ccf399b 100644
--- a/networking/zcip.c
+++ b/networking/zcip.c
@@ -31,12 +31,14 @@
* 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 <errno.h>
#include <stdlib.h>
#include <stdio.h>
@@ -61,12 +63,11 @@
#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;
@@ -89,13 +90,29 @@ 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)"
+static const unsigned char ZCIP_VERSION[] = "0.75 (18 April 2005)";
+static char *prog;
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;
-/*
+#ifdef DEBUG
+
+#define DBG(fmt,args...) \
+ fprintf(stderr, "%s: " fmt , prog , ## args)
+#define VDBG(fmt,args...) do { \
+ if (verbose) fprintf(stderr, "%s: " fmt , prog ,## args); \
+ } while (0)
+#else
+
+#define DBG(fmt,args...) \
+ do { } while (0)
+#define VDBG DBG
+#endif /* DEBUG */
+
+/**
* Pick a random link local IP address on 169.254/16, except that
* the first and last 256 addresses are reserved.
*/
@@ -111,7 +128,7 @@ pick(struct in_addr *ip)
ip->s_addr = htonl((LINKLOCAL_ADDR + 0x0100) + tmp);
}
-/*
+/**
* Broadcast an ARP packet.
*/
static int
@@ -121,12 +138,12 @@ arp(int fd, struct sockaddr *saddr, int op,
{
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;
@@ -137,15 +154,15 @@ arp(int fd, struct sockaddr *saddr, int op,
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
@@ -155,19 +172,21 @@ run(char *script, char *arg, char *intf, struct in_addr *ip)
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) {
@@ -175,7 +194,8 @@ run(char *script, char *arg, char *intf, struct in_addr *ip)
goto bad;
}
if (WEXITSTATUS(status) != 0) {
- bb_perror_msg("script %s failed, exit=%d", script, WEXITSTATUS(status));
+ fprintf(stderr, "%s: script %s failed, exit=%d\n",
+ prog, script, WEXITSTATUS(status));
return -errno;
}
}
@@ -187,7 +207,31 @@ bad:
return status;
}
-/*
+#ifndef NO_BUSYBOX
+#include "busybox.h"
+#endif
+
+/**
+ * Print usage information.
+ */
+static void __attribute__ ((noreturn))
+usage(const char *msg)
+{
+ fprintf(stderr, "%s: %s\n", prog, msg);
+#ifdef NO_BUSYBOX
+ fprintf(stderr, "Usage: %s [OPTIONS] ifname script\n"
+ "\t-f foreground mode (implied by -v)\n"
+ "\t-q quit after address (no daemon)\n"
+ "\t-r 169.254.x.x request this address first\n"
+ "\t-v verbose; show version\n",
+ prog);
+ exit(0);
+#else
+ bb_show_usage();
+#endif
+}
+
+/**
* Return milliseconds of random delay, up to "secs" seconds.
*/
static inline unsigned
@@ -196,72 +240,85 @@ ms_rdelay(unsigned secs)
return lrand48() % (secs * 1000);
}
-/*
+/**
* main program
*/
-
-#define FOREGROUND 1
-#define QUIT 2
-#define REQUEST 4
-#define VERBOSE 8
+int
+main(int argc, char *argv[])
+ __attribute__ ((weak, alias ("zcip_main")));
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
+ prog = argv[0];
+ 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) {
+ usage("invalid link address");
+ }
+ continue;
+ case 'v':
+ if (!verbose)
+ printf("%s: version %s\n", prog, ZCIP_VERSION);
+ verbose++;
+ foreground = 1;
+ continue;
+ default:
+ usage("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 ? */
-
- openlog(bb_applet_name, 0, LOG_DAEMON);
-
- /* initialize the interface (modprobe, ifup, etc) */
+ if (optind != argc || !intf)
+ usage("wrong number of arguments");
+ openlog(prog, 0, LOG_DAEMON);
+
+ // 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));
- /* 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;
@@ -269,7 +326,7 @@ fail:
struct ifreq ifr;
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) {
@@ -278,37 +335,37 @@ fail:
}
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;
@@ -318,7 +375,7 @@ fail:
fds[0].events = POLLIN;
fds[0].revents = 0;
- /* poll, being ready to adjust current timeout */
+ // poll, being ready to adjust current timeout
if (timeout > 0) {
gettimeofday(&tv1, NULL);
tv1.tv_usec += (timeout % 1000) * 1000;
@@ -329,17 +386,21 @@ fail:
tv1.tv_sec += timeout / 1000;
} else if (timeout == 0) {
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.
}
+ 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);
@@ -350,36 +411,38 @@ fail:
} 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;
@@ -391,33 +454,46 @@ fail:
}
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.
+ fprintf(stderr, "%s %s: poll error\n",
+ prog, 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);
@@ -428,26 +504,28 @@ collision:
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)
@@ -463,11 +541,10 @@ collision:
}
}
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));
- }
+ prog, intf, why, strerror(errno));
return EXIT_FAILURE;
}
generated by cgit v1.1 at 2024-12-29 14:03:23 +0000