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....

1 files changed, 109 insertions, 186 deletions

diff --git a/networking/zcip.c b/networking/zcip.c
index ccf399bb7..de9ea7675 100644
--- a/networking/zcip.c
+++ b/networking/zcip.c
@@ -31,14 +31,12 @@
  * certainly be used.  Its naming is built over multicast DNS.
  */
 
-// #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)
-
+/* 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>
@@ -63,11 +61,12 @@
 
 #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;
@@ -90,29 +89,13 @@ static const unsigned ANNOUNCE_NUM = 2;
 static const unsigned ANNOUNCE_INTERVAL = 2;
 static const time_t DEFEND_INTERVAL = 10;
 
-static const unsigned char ZCIP_VERSION[] = "0.75 (18 April 2005)";
-static char *prog;
+#define ZCIP_VERSION     "0.75 (18 April 2005)"
 
 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.
  */
@@ -128,7 +111,7 @@ pick(struct in_addr *ip)
         ip->s_addr = htonl((LINKLOCAL_ADDR + 0x0100) + tmp);
 }
 
-/**
+/*
  * Broadcast an ARP packet.
  */
 static int
@@ -138,12 +121,12 @@ 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;
@@ -154,15 +137,15 @@ 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) {
-                perror("sendto");
+                bb_perror_msg("sendto");
                 return -errno;
         }
         return 0;
 }
 
-/**
+/*
  * Run a script.
  */
 static int
@@ -172,21 +155,19 @@ 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);
-                        setenv("ip", addr, 1);
+                        xsetenv("ip", addr);
                         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);
-                        perror("execl");
-                        _exit(EXIT_FAILURE);
+                        bb_perror_msg_and_die("execl");
                 } 
 
                 if (waitpid(pid, &status, 0) <= 0) {
@@ -194,8 +175,7 @@ run(char *script, char *arg, char *intf, struct in_addr *ip)
                         goto bad;
                 }
                 if (WEXITSTATUS(status) != 0) {
-                        fprintf(stderr, "%s: script %s failed, exit=%d\n",
-                                        prog, script, WEXITSTATUS(status));
+                        bb_perror_msg("script %s failed, exit=%d", script, WEXITSTATUS(status));
                         return -errno;
                 }
         }
@@ -207,31 +187,7 @@ 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
@@ -240,85 +196,72 @@ ms_rdelay(unsigned secs)
         return lrand48() % (secs * 1000);
 }
 
-/**
+/*
  * main program
  */
-int
-main(int argc, char *argv[])
-        __attribute__ ((weak, alias ("zcip_main")));
+
+#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;
-        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");
-                }
+        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 (optind < argc - 1) {
-                intf = argv[optind++];
-                setenv("interface", intf, 1);
-                script = argv[optind++];
+        
+        if (t & VERBOSE) {
+                bb_printf("%s: version %s\n", bb_applet_name, ZCIP_VERSION);
         }
-        if (optind != argc || !intf)
-                usage("wrong number of arguments");
-        openlog(prog, 0, LOG_DAEMON);
-
-        // initialize the interface (modprobe, ifup, etc)
+        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");
+        }
+        
+        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 (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:
-                foreground = 1;
+                t |= FOREGROUND;
                 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;
@@ -326,7 +269,7 @@ 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) {
@@ -335,37 +278,37 @@ 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 (!foreground) {
-                if (daemon(0, verbose) < 0) {
+        /* daemonize now; don't delay system startup */
+        if (!(t & FOREGROUND)) {
+                if (daemon(0, (t & 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;
@@ -375,7 +318,7 @@ 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;
@@ -386,21 +329,17 @@ 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);
@@ -411,38 +350,36 @@ 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 (quit)
+                                        /* NOTE:  all other exit paths
+                                           should deconfig ... */
+                                        if (t & 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;
@@ -454,46 +391,33 @@ fail:
                         }
                         if ((fds[0].revents & POLLIN) == 0) {
                                 if (fds[0].revents & POLLERR) {
-                                        // FIXME: links routinely go down;
-                                        // this shouldn't necessarily exit.
-                                        fprintf(stderr, "%s %s: poll error\n",
-                                                        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;
 }