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 ccf399b..de9ea76 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;
 }