On Tuesday 19 April 2005 21:10, Tito wrote and today added:
> Hi, > this is a first attempt of size optimization for zcip taking into account all > the hints given so far on the list. > I've applied just the more obvious busyboxifications so maybe it could be > optimized more. BTW: I've ripped out a lot of debug code and changed c++ // comments to /* */ as both were rather confusing for a newbie like me. ;-) Sorry to the author for that. I know that this makes mantaining the code easier, but I'm simple minded....
This commit is contained in:
Rob Landley
parent
6624daeb4d
commit
8445a9ff99
@ -430,6 +430,7 @@ extern void run_shell ( const char *shell, int loginshell, const char *command,
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);
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extern int run_parts(char **args, const unsigned char test_mode, char **env);
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extern int restricted_shell ( const char *shell );
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extern void xsetenv ( const char *key, const char *value );
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extern void setup_environment ( const char *shell, int loginshell, int changeenv, const struct passwd *pw );
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extern int correct_password ( const struct passwd *pw );
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extern char *pw_encrypt(const char *clear, const char *salt);
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@ -42,7 +42,7 @@
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#define DEFAULT_LOGIN_PATH "/bin:/usr/bin"
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#define DEFAULT_ROOT_LOGIN_PATH "/usr/sbin:/bin:/usr/bin:/sbin"
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static void xsetenv ( const char *key, const char *value )
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void xsetenv ( const char *key, const char *value )
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{
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if ( setenv ( key, value, 1 ))
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bb_error_msg_and_die (bb_msg_memory_exhausted);
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@ -31,14 +31,12 @@
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* certainly be used. Its naming is built over multicast DNS.
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*/
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// #define DEBUG
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// TODO:
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// - more real-world usage/testing, especially daemon mode
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// - kernel packet filters to reduce scheduling noise
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// - avoid silent script failures, especially under load...
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// - link status monitoring (restart on link-up; stop on link-down)
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/* TODO:
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- more real-world usage/testing, especially daemon mode
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- kernel packet filters to reduce scheduling noise
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- avoid silent script failures, especially under load...
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- link status monitoring (restart on link-up; stop on link-down)
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*/
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#include <errno.h>
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#include <stdlib.h>
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#include <stdio.h>
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@ -63,11 +61,12 @@
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#include <linux/if_packet.h>
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#include <linux/sockios.h>
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#include "busybox.h"
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#include "libbb.h"
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struct arp_packet {
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struct ether_header hdr;
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// FIXME this part is netinet/if_ether.h "struct ether_arp"
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/* FIXME this part is netinet/if_ether.h "struct ether_arp" */
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struct arphdr arp;
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struct ether_addr source_addr;
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struct in_addr source_ip;
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@ -90,29 +89,13 @@ static const unsigned ANNOUNCE_NUM = 2;
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static const unsigned ANNOUNCE_INTERVAL = 2;
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static const time_t DEFEND_INTERVAL = 10;
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static const unsigned char ZCIP_VERSION[] = "0.75 (18 April 2005)";
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static char *prog;
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#define ZCIP_VERSION "0.75 (18 April 2005)"
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static const struct in_addr null_ip = { 0 };
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static const struct ether_addr null_addr = { {0, 0, 0, 0, 0, 0} };
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static int verbose = 0;
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#ifdef DEBUG
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#define DBG(fmt,args...) \
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fprintf(stderr, "%s: " fmt , prog , ## args)
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#define VDBG(fmt,args...) do { \
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if (verbose) fprintf(stderr, "%s: " fmt , prog ,## args); \
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} while (0)
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#else
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#define DBG(fmt,args...) \
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do { } while (0)
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#define VDBG DBG
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#endif /* DEBUG */
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/**
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/*
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* Pick a random link local IP address on 169.254/16, except that
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* the first and last 256 addresses are reserved.
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*/
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@ -128,7 +111,7 @@ pick(struct in_addr *ip)
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ip->s_addr = htonl((LINKLOCAL_ADDR + 0x0100) + tmp);
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}
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/**
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/*
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* Broadcast an ARP packet.
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*/
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static int
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@ -138,12 +121,12 @@ arp(int fd, struct sockaddr *saddr, int op,
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{
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struct arp_packet p;
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// ether header
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/* ether header */
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p.hdr.ether_type = htons(ETHERTYPE_ARP);
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memcpy(p.hdr.ether_shost, source_addr, ETH_ALEN);
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memset(p.hdr.ether_dhost, 0xff, ETH_ALEN);
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// arp request
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/* arp request */
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p.arp.ar_hrd = htons(ARPHRD_ETHER);
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p.arp.ar_pro = htons(ETHERTYPE_IP);
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p.arp.ar_hln = ETH_ALEN;
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@ -154,15 +137,15 @@ arp(int fd, struct sockaddr *saddr, int op,
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memcpy(&p.target_addr, target_addr, ETH_ALEN);
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memcpy(&p.target_ip, &target_ip, sizeof (p.target_ip));
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// send it
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/* send it */
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if (sendto(fd, &p, sizeof (p), 0, saddr, sizeof (*saddr)) < 0) {
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perror("sendto");
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bb_perror_msg("sendto");
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return -errno;
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}
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return 0;
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}
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/**
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/*
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* Run a script.
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*/
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static int
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@ -172,21 +155,19 @@ run(char *script, char *arg, char *intf, struct in_addr *ip)
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char *why;
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if (script != NULL) {
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VDBG("%s run %s %s\n", intf, script, arg);
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if (ip != NULL) {
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char *addr = inet_ntoa(*ip);
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setenv("ip", addr, 1);
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xsetenv("ip", addr);
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syslog(LOG_INFO, "%s %s %s", arg, intf, addr);
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}
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pid = vfork();
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if (pid < 0) { // error
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if (pid < 0) { /* error */
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why = "vfork";
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goto bad;
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} else if (pid == 0) { // child
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} else if (pid == 0) { /* child */
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execl(script, script, arg, NULL);
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perror("execl");
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_exit(EXIT_FAILURE);
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bb_perror_msg_and_die("execl");
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}
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if (waitpid(pid, &status, 0) <= 0) {
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@ -194,8 +175,7 @@ run(char *script, char *arg, char *intf, struct in_addr *ip)
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goto bad;
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}
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if (WEXITSTATUS(status) != 0) {
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fprintf(stderr, "%s: script %s failed, exit=%d\n",
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prog, script, WEXITSTATUS(status));
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bb_perror_msg("script %s failed, exit=%d", script, WEXITSTATUS(status));
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return -errno;
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}
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}
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@ -207,31 +187,7 @@ bad:
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return status;
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}
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#ifndef NO_BUSYBOX
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#include "busybox.h"
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#endif
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/**
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* Print usage information.
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*/
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static void __attribute__ ((noreturn))
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usage(const char *msg)
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{
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fprintf(stderr, "%s: %s\n", prog, msg);
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#ifdef NO_BUSYBOX
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fprintf(stderr, "Usage: %s [OPTIONS] ifname script\n"
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"\t-f foreground mode (implied by -v)\n"
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"\t-q quit after address (no daemon)\n"
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"\t-r 169.254.x.x request this address first\n"
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"\t-v verbose; show version\n",
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prog);
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exit(0);
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#else
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bb_show_usage();
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#endif
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}
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/**
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/*
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* Return milliseconds of random delay, up to "secs" seconds.
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*/
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static inline unsigned
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@ -240,85 +196,72 @@ ms_rdelay(unsigned secs)
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return lrand48() % (secs * 1000);
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}
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/**
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/*
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* main program
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*/
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int
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main(int argc, char *argv[])
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__attribute__ ((weak, alias ("zcip_main")));
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#define FOREGROUND 1
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#define QUIT 2
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#define REQUEST 4
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#define VERBOSE 8
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int zcip_main(int argc, char *argv[])
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{
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char *intf = NULL;
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char *script = NULL;
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int quit = 0;
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int foreground = 0;
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char *why;
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struct sockaddr saddr;
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struct ether_addr addr;
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struct in_addr ip = { 0 };
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int fd;
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int ready = 0;
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suseconds_t timeout = 0; // milliseconds
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suseconds_t timeout = 0; /* milliseconds */
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time_t defend = 0;
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unsigned conflicts = 0;
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unsigned nprobes = 0;
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unsigned nclaims = 0;
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int t;
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unsigned long t;
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// parse commandline: prog [options] ifname script
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prog = argv[0];
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while ((t = getopt(argc, argv, "fqr:v")) != EOF) {
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switch (t) {
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case 'f':
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foreground = 1;
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continue;
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case 'q':
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quit = 1;
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continue;
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case 'r':
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if (inet_aton(optarg, &ip) == 0
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|| (ntohl(ip.s_addr) & IN_CLASSB_NET)
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!= LINKLOCAL_ADDR) {
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usage("invalid link address");
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}
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continue;
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case 'v':
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if (!verbose)
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printf("%s: version %s\n", prog, ZCIP_VERSION);
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verbose++;
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foreground = 1;
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continue;
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default:
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usage("bad option");
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}
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bb_opt_complementaly = "vf";
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/* parse commandline: prog [options] ifname script */
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t = bb_getopt_ulflags(argc, argv, "fqr:v", &why); /* reuse char* why */
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argc -= optind;
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argv += optind;
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if ((t & 0x80000000UL) || (argc < 1) || (argc > 2)) {
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bb_show_usage();
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}
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if (optind < argc - 1) {
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intf = argv[optind++];
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setenv("interface", intf, 1);
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script = argv[optind++];
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if (t & VERBOSE) {
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bb_printf("%s: version %s\n", bb_applet_name, ZCIP_VERSION);
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}
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if (optind != argc || !intf)
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usage("wrong number of arguments");
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openlog(prog, 0, LOG_DAEMON);
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if ((t & REQUEST) && (inet_aton(why, &ip) == 0 || (ntohl(ip.s_addr) & IN_CLASSB_NET) != LINKLOCAL_ADDR)) {
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bb_perror_msg_and_die("invalid link address");
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}
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intf = argv[0];
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xsetenv("interface", intf);
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script = argv[1]; /* Could be NULL ? */
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openlog(bb_applet_name, 0, LOG_DAEMON);
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// initialize the interface (modprobe, ifup, etc)
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/* initialize the interface (modprobe, ifup, etc) */
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if (run(script, "init", intf, NULL) < 0)
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return EXIT_FAILURE;
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// initialize saddr
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/* initialize saddr */
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memset(&saddr, 0, sizeof (saddr));
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strncpy(saddr.sa_data, intf, sizeof (saddr.sa_data));
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// open an ARP socket
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/* open an ARP socket */
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if ((fd = socket(PF_PACKET, SOCK_PACKET, htons(ETH_P_ARP))) < 0) {
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why = "open";
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fail:
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foreground = 1;
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t |= FOREGROUND;
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goto bad;
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}
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// bind to the interface's ARP socket
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/* bind to the interface's ARP socket */
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if (bind(fd, &saddr, sizeof (saddr)) < 0) {
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why = "bind";
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goto fail;
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@ -326,7 +269,7 @@ fail:
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struct ifreq ifr;
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short seed[3];
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// get the interface's ethernet address
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/* get the interface's ethernet address */
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memset(&ifr, 0, sizeof (ifr));
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strncpy(ifr.ifr_name, intf, sizeof (ifr.ifr_name));
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if (ioctl(fd, SIOCGIFHWADDR, &ifr) < 0) {
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@ -335,37 +278,37 @@ fail:
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}
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memcpy(&addr, &ifr.ifr_hwaddr.sa_data, ETH_ALEN);
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// start with some stable ip address, either a function of
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// the hardware address or else the last address we used.
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// NOTE: the sequence of addresses we try changes only
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// depending on when we detect conflicts.
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/* start with some stable ip address, either a function of
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the hardware address or else the last address we used.
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NOTE: the sequence of addresses we try changes only
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depending on when we detect conflicts. */
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memcpy(seed, &ifr.ifr_hwaddr.sa_data, ETH_ALEN);
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seed48(seed);
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if (ip.s_addr == 0)
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pick(&ip);
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}
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// FIXME cases to handle:
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// - zcip already running!
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// - link already has local address... just defend/update
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/* FIXME cases to handle:
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- zcip already running!
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- link already has local address... just defend/update */
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// daemonize now; don't delay system startup
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if (!foreground) {
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if (daemon(0, verbose) < 0) {
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/* daemonize now; don't delay system startup */
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if (!(t & FOREGROUND)) {
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if (daemon(0, (t & VERBOSE)) < 0) {
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why = "daemon";
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goto bad;
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}
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syslog(LOG_INFO, "start, interface %s", intf);
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}
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// run the dynamic address negotiation protocol,
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// restarting after address conflicts:
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// - start with some address we want to try
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// - short random delay
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// - arp probes to see if another host else uses it
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// - arp announcements that we're claiming it
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// - use it
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// - defend it, within limits
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/* run the dynamic address negotiation protocol,
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restarting after address conflicts:
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- start with some address we want to try
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- short random delay
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- arp probes to see if another host else uses it
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- arp announcements that we're claiming it
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- use it
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- defend it, within limits */
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while (1) {
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struct pollfd fds[1];
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struct timeval tv1;
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@ -375,7 +318,7 @@ fail:
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fds[0].events = POLLIN;
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fds[0].revents = 0;
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// poll, being ready to adjust current timeout
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/* poll, being ready to adjust current timeout */
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if (timeout > 0) {
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gettimeofday(&tv1, NULL);
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tv1.tv_usec += (timeout % 1000) * 1000;
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@ -386,21 +329,17 @@ fail:
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tv1.tv_sec += timeout / 1000;
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} else if (timeout == 0) {
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timeout = ms_rdelay(PROBE_WAIT);
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// FIXME setsockopt(fd, SO_ATTACH_FILTER, ...) to
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// make the kernel filter out all packets except
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// ones we'd care about.
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/* FIXME setsockopt(fd, SO_ATTACH_FILTER, ...) to
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make the kernel filter out all packets except
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ones we'd care about. */
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}
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VDBG("...wait %ld %s nprobes=%d, nclaims=%d\n",
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timeout, intf, nprobes, nclaims);
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switch (poll(fds, 1, timeout)) {
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// timeouts trigger protocol transitions
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/* timeouts trigger protocol transitions */
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case 0:
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// probes
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/* probes */
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if (nprobes < PROBE_NUM) {
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nprobes++;
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VDBG("probe/%d %s@%s\n",
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nprobes, intf, inet_ntoa(ip));
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(void)arp(fd, &saddr, ARPOP_REQUEST,
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&addr, null_ip,
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&null_addr, ip);
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@ -411,38 +350,36 @@ fail:
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} else
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timeout = ANNOUNCE_WAIT * 1000;
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}
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// then announcements
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/* then announcements */
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else if (nclaims < ANNOUNCE_NUM) {
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nclaims++;
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VDBG("announce/%d %s@%s\n",
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nclaims, intf, inet_ntoa(ip));
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(void)arp(fd, &saddr, ARPOP_REQUEST,
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&addr, ip,
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&addr, ip);
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if (nclaims < ANNOUNCE_NUM) {
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timeout = ANNOUNCE_INTERVAL * 1000;
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} else {
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// link is ok to use earlier
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/* link is ok to use earlier */
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run(script, "config", intf, &ip);
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ready = 1;
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conflicts = 0;
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timeout = -1;
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|
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// NOTE: all other exit paths
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// should deconfig ...
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if (quit)
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/* NOTE: all other exit paths
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should deconfig ... */
|
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if (t & QUIT)
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return EXIT_SUCCESS;
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// FIXME update filters
|
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/* FIXME update filters */
|
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}
|
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}
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break;
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|
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// packets arriving
|
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/* packets arriving */
|
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case 1:
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// maybe adjust timeout
|
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/* maybe adjust timeout */
|
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if (timeout > 0) {
|
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struct timeval tv2;
|
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|
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|
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gettimeofday(&tv2, NULL);
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if (timercmp(&tv1, &tv2, <)) {
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timeout = -1;
|
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@ -454,46 +391,33 @@ fail:
|
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}
|
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if ((fds[0].revents & POLLIN) == 0) {
|
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if (fds[0].revents & POLLERR) {
|
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// FIXME: links routinely go down;
|
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// this shouldn't necessarily exit.
|
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fprintf(stderr, "%s %s: poll error\n",
|
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prog, intf);
|
||||
/* FIXME: links routinely go down;
|
||||
this shouldn't necessarily exit. */
|
||||
bb_perror_msg("%s: poll error", 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);
|
||||
|
||||
@ -504,28 +428,26 @@ 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)
|
||||
@ -541,10 +463,11 @@ collision:
|
||||
}
|
||||
}
|
||||
bad:
|
||||
if (foreground)
|
||||
perror(why);
|
||||
else
|
||||
if ( t & FOREGROUND) {
|
||||
bb_perror_msg(why);
|
||||
} else {
|
||||
syslog(LOG_ERR, "%s %s, %s error: %s",
|
||||
prog, intf, why, strerror(errno));
|
||||
bb_applet_name, intf, why, strerror(errno));
|
||||
}
|
||||
return EXIT_FAILURE;
|
||||
}
|
||||
|
||||
Loading…
Reference in New Issue
Block a user