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cdd1f732b

Denis Vlasenko

2008-10-10

FAILED Duration: 30s

Subject

zcip: code size optimizations, improved help text and comments

Binary

No binary (build failed)

Architecture & Compiler Flags

Architecture: x86_64-linux-gnu Compiler: gcc (Ubuntu 11.4.0-1ubuntu1~22.04.3) 11.4.0

—

Build Log

(log yok)

Commit Diff GitHub →

include/usage.h +4 -1 networking/zcip.c +79 -62

include/usage.h+4 -1

@@ -4680,8 +4680,11 @@
	"Manage a ZeroConf IPv4 link-local address\n" \
	"\nOptions:" \
	"\n -f Run in foreground" \
-	"\n -q Quit after address (no daemon)" \
+	"\n -q Quit after obtaining address" \
	"\n -r 169.254.x.x Request this address first" \
	"\n -v Verbose" \
+	"\n" \
+	"\nWith no -q, runs continuously monitoring for ARP conflicts," \
+	"\nexits only on I/O errors (link down etc)" \

	#endif /* __BB_USAGE_H__ */

networking/zcip.c+79 -62

@@ -75,35 +75,40 @@ enum {
	};

	struct globals {
-	char *intf;
	struct sockaddr saddr;
+	struct ether_addr eth_addr;
	};
	#define G ((struct globals)&bb_common_bufsiz1)
-	#define intf (G.intf )
-	#define saddr (G.saddr)
+	#define saddr (G.saddr )
+	#define eth_addr (G.eth_addr)


	/**
	* Pick a random link local IP address on 169.254/16, except that
	* the first and last 256 addresses are reserved.
	*/
-	static void pick(struct in_addr *ip)
+	static uint32_t pick(void)
	{
	unsigned tmp;

	do {
	tmp = rand() & IN_CLASSB_HOST;
	} while (tmp > (IN_CLASSB_HOST - 0x0200));
-	ip->s_addr = htonl((LINKLOCAL_ADDR + 0x0100) + tmp);
+	return htonl((LINKLOCAL_ADDR + 0x0100) + tmp);
	}

	/**
	* Broadcast an ARP packet.
	*/
-	static void arp(int op,
-	const struct ether_addr *source_eth, struct in_addr source_ip,
+	static void arp(
+	/* int op, - always ARPOP_REQUEST */
+	/* const struct ether_addr source_eth, - always &eth_addr /
+	struct in_addr source_ip,
	const struct ether_addr *target_eth, struct in_addr target_ip)
	{
+	enum { op = ARPOP_REQUEST };
+	#define source_eth (&eth_addr)
+
	struct arp_packet p;
	memset(&p, 0, sizeof(p));

@@ -124,38 +129,44 @@ static void arp(int op,
	memcpy(&p.arp.arp_tpa, &target_ip, sizeof(p.arp.arp_tpa));

	// send it
+	// Even though sock_fd is already bound to saddr, just send()
+	// won't work, because "socket is not connected"
+	// (and connect() won't fix that, "operation not supported").
+	// Thus we sendto() to saddr. I wonder which sockaddr
+	// (from bind() or from sendto()?) kernel actually uses
+	// to determine iface to emit the packet from...
	xsendto(sock_fd, &p, sizeof(p), &saddr, sizeof(saddr));
-
-	// Currently all callers ignore errors, that's why returns are
-	// commented out...
-	//return 0;
+	#undef source_eth
	}

	/**
-	* Run a script. argv[2] is already NULL.
+	* Run a script.
+	* argv[0]:intf argv[1]:script_name argv[2]:junk argv[3]:NULL
	*/
-	static int run(char argv[3], struct in_addr ip)
+	static int run(char argv[3], const char param, 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]);
+	argv[2] = (char*)param;
+
+	VDBG("%s run %s %s\n", argv[0], argv[1], argv[2]);

	if (ip) {
	addr = inet_ntoa(*ip);
	xsetenv("ip", addr);
	fmt -= 3;
	}
-	bb_info_msg(fmt, argv[1], intf, addr);
+	bb_info_msg(fmt, argv[2], argv[0], addr);

-	status = wait4pid(spawn(argv));
+	status = wait4pid(spawn(argv + 1));
	if (status < 0) {
-	bb_perror_msg("%s %s %s" + 3, argv[1], intf);
+	bb_perror_msg("%s %s %s" + 3, argv[2], argv[0]);
	return -errno;
	}
	if (status != 0)
-	bb_error_msg("script %s %s failed, exitcode=%d", argv[0], argv[1], status);
+	bb_error_msg("script %s %s failed, exitcode=%d", argv[1], argv[2], status);
	return status;
	}

@@ -173,8 +184,7 @@ static ALWAYS_INLINE unsigned random_delay_ms(unsigned secs)
	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;
+	int state;
	char *r_opt;
	unsigned opts;

@@ -184,7 +194,6 @@ int zcip_main(int argc, char **argv)
	const struct ether_addr null_addr;
	struct in_addr ip;
	struct ifreq ifr;
-	char *script_av[3];
	int timeout_ms; /* must be signed */
	unsigned conflicts;
	unsigned nprobes;
@@ -196,7 +205,6 @@ int zcip_main(int argc, char **argv)
	#define null_addr (L.null_addr )
	#define ip (L.ip )
	#define ifr (L.ifr )
-	#define script_av (L.script_av )
	#define timeout_ms (L.timeout_ms)
	#define conflicts (L.conflicts )
	#define nprobes (L.nprobes )
@@ -234,29 +242,33 @@ int zcip_main(int argc, char **argv)
	}
	}
	argc -= optind;
-	argv += optind;
+	argv += optind - 1;
+
+	/* Now: argv[0]:junk argv[1]:intf argv[2]:script argv[3]:NULL */
+	/* We need to make space for script argument: */
+	argv[0] = argv[1];
+	argv[1] = argv[2];
+	/* Now: argv[0]:intf argv[1]:script argv[2]:junk argv[3]:NULL */
+	#define argv_intf (argv[0])

-	intf = argv[0];
-	script_av[0] = argv[1];
-	xsetenv("interface", intf);
+	xsetenv("interface", argv_intf);

	// initialize the interface (modprobe, ifup, etc)
-	script_av[1] = (char*)"init";
-	if (run(script_av, NULL))
+	if (run(argv, "init", 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));
+	safe_strncpy(saddr.sa_data, argv_intf, sizeof(saddr.sa_data));

	// bind to the interface's ARP socket
	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));
+	strncpy(ifr.ifr_name, argv_intf, sizeof(ifr.ifr_name));
	xioctl(sock_fd, SIOCGIFHWADDR, &ifr);
	memcpy(&eth_addr, &ifr.ifr_hwaddr.sa_data, ETH_ALEN);

@@ -267,12 +279,11 @@ int zcip_main(int argc, char **argv)
	// NOTE: the sequence of addresses we try changes only
	// depending on when we detect conflicts.
	{
-	uint32_t t;
-	memcpy(&t, (char*)&eth_addr + 2, 4);
+	uint32_t t = get_unaligned_u32p((uint32_t ) ((char )&eth_addr + 2));
	srand(t);
	}
	if (ip.s_addr == 0)
-	pick(&ip);
+	ip.s_addr = pick();

	// FIXME cases to handle:
	// - zcip already running!
@@ -283,7 +294,7 @@ int zcip_main(int argc, char **argv)
	#if BB_MMU
	bb_daemonize(0 /was: DAEMON_CHDIR_ROOT/);
	#endif
-	bb_info_msg("start, interface %s", intf);
+	bb_info_msg("start, interface %s", argv_intf);
	}

	// run the dynamic address negotiation protocol,
@@ -294,6 +305,14 @@ int zcip_main(int argc, char **argv)
	// - arp announcements that we're claiming it
	// - use it
	// - defend it, within limits
+	// exit if:
+	// - address is successfully obtained and -q was given:
+	// run "<script> config", then exit with exitcode 0
+	// - poll error (when does this happen?)
+	// - read error (when does this happen?)
+	// - sendto error (in arp()) (when does this happen?)
+	// - revents & POLLERR (link down). run "<script> deconfig" first
+	state = PROBE;
	while (1) {
	struct pollfd fds[1];
	unsigned deadline_us;
@@ -316,7 +335,7 @@ int zcip_main(int argc, char **argv)
	deadline_us = MONOTONIC_US() + timeout_ms * 1000;

	VDBG("...wait %d %s nprobes=%u, nclaims=%u\n",
-	timeout_ms, intf, nprobes, nclaims);
+	timeout_ms, argv_intf, nprobes, nclaims);

	switch (safe_poll(fds, 1, timeout_ms)) {

@@ -334,9 +353,9 @@ int zcip_main(int argc, char **argv)
	if (nprobes < PROBE_NUM) {
	nprobes++;
	VDBG("probe/%u %s@%s\n",
-	nprobes, intf, inet_ntoa(ip));
-	arp(ARPOP_REQUEST,
-	&eth_addr, null_ip,
+	nprobes, argv_intf, inet_ntoa(ip));
+	arp(/* ARPOP_REQUEST, */
+	/* &eth_addr, */ null_ip,
	&null_addr, ip);
	timeout_ms = PROBE_MIN * 1000;
	timeout_ms += random_delay_ms(PROBE_MAX - PROBE_MIN);
@@ -346,9 +365,9 @@ int zcip_main(int argc, char **argv)
	state = ANNOUNCE;
	nclaims = 0;
	VDBG("announce/%u %s@%s\n",
-	nclaims, intf, inet_ntoa(ip));
-	arp(ARPOP_REQUEST,
-	&eth_addr, ip,
+	nclaims, argv_intf, inet_ntoa(ip));
+	arp(/* ARPOP_REQUEST, */
+	/* &eth_addr, */ ip,
	&eth_addr, ip);
	timeout_ms = ANNOUNCE_INTERVAL * 1000;
	}
@@ -359,9 +378,9 @@ int zcip_main(int argc, char **argv)
	state = ANNOUNCE;
	nclaims = 0;
	VDBG("announce/%u %s@%s\n",
-	nclaims, intf, inet_ntoa(ip));
-	arp(ARPOP_REQUEST,
-	&eth_addr, ip,
+	nclaims, argv_intf, inet_ntoa(ip));
+	arp(/* ARPOP_REQUEST, */
+	/* &eth_addr, */ ip,
	&eth_addr, ip);
	timeout_ms = ANNOUNCE_INTERVAL * 1000;
	break;
@@ -371,9 +390,9 @@ int zcip_main(int argc, char **argv)
	if (nclaims < ANNOUNCE_NUM) {
	nclaims++;
	VDBG("announce/%u %s@%s\n",
-	nclaims, intf, inet_ntoa(ip));
-	arp(ARPOP_REQUEST,
-	&eth_addr, ip,
+	nclaims, argv_intf, inet_ntoa(ip));
+	arp(/* ARPOP_REQUEST, */
+	/* &eth_addr, */ ip,
	&eth_addr, ip);
	timeout_ms = ANNOUNCE_INTERVAL * 1000;
	}
@@ -382,8 +401,7 @@ int zcip_main(int argc, char **argv)
	state = MONITOR;
	// link is ok to use earlier
	// FIXME update filters
-	script_av[1] = (char*)"config";
-	run(script_av, &ip);
+	run(argv, "config", &ip);
	ready = 1;
	conflicts = 0;
	timeout_ms = -1; // Never timeout in the monitor state.
@@ -403,7 +421,7 @@ int zcip_main(int argc, char **argv)
	default:
	// Invalid, should never happen. Restart the whole protocol.
	state = PROBE;
-	pick(&ip);
+	ip.s_addr = pick();
	timeout_ms = 0;
	nprobes = 0;
	nclaims = 0;
@@ -432,10 +450,9 @@ int zcip_main(int argc, char **argv)
	if (fds[0].revents & POLLERR) {
	// FIXME: links routinely go down;
	// this shouldn't necessarily exit.
-	bb_error_msg("iface %s is down", intf);
+	bb_error_msg("iface %s is down", argv_intf);
	if (ready) {
-	script_av[1] = (char*)"deconfig";
-	run(script_av, &ip);
+	run(argv, "deconfig", &ip);
	}
	return EXIT_FAILURE;
	}
@@ -455,7 +472,7 @@ int zcip_main(int argc, char **argv)
	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.eth.ether_type),
+	argv_intf, ntohs(p.eth.ether_type),
	ntohs(p.arp.arp_op));
	VDBG("\tsource=%s %s\n",
	ether_ntoa(sha),
@@ -494,13 +511,13 @@ int zcip_main(int argc, char **argv)
	if (source_ip_conflict \|\| target_ip_conflict) {
	conflicts++;
	if (conflicts >= MAX_CONFLICTS) {
-	VDBG("%s ratelimit\n", intf);
+	VDBG("%s ratelimit\n", argv_intf);
	timeout_ms = RATE_LIMIT_INTERVAL * 1000;
	state = RATE_LIMIT_PROBE;
	}

	// restart the whole protocol
-	pick(&ip);
+	ip.s_addr = pick();
	timeout_ms = 0;
	nprobes = 0;
	nclaims = 0;
@@ -512,8 +529,8 @@ int zcip_main(int argc, char **argv)
	VDBG("monitor conflict -- defending\n");
	state = DEFEND;
	timeout_ms = DEFEND_INTERVAL * 1000;
-	arp(ARPOP_REQUEST,
-	&eth_addr, ip,
+	arp(/* ARPOP_REQUEST, */
+	/* &eth_addr, */ ip,
	&eth_addr, ip);
	}
	break;
@@ -523,11 +540,10 @@ int zcip_main(int argc, char **argv)
	state = PROBE;
	VDBG("defend conflict -- starting over\n");
	ready = 0;
-	script_av[1] = (char*)"deconfig";
-	run(script_av, &ip);
+	run(argv, "deconfig", &ip);

	// restart the whole protocol
-	pick(&ip);
+	ip.s_addr = pick();
	timeout_ms = 0;
	nprobes = 0;
	nclaims = 0;
@@ -537,7 +553,7 @@ int zcip_main(int argc, char **argv)
	// Invalid, should never happen. Restart the whole protocol.
	VDBG("invalid state -- starting over\n");
	state = PROBE;
-	pick(&ip);
+	ip.s_addr = pick();
	timeout_ms = 0;
	nprobes = 0;
	nclaims = 0;
@@ -546,4 +562,5 @@ int zcip_main(int argc, char **argv)
	break; // case 1 (packets arriving)
	} // switch poll
	} // while (1)
+	#undef argv_intf
	}