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zcip: code size optimizations, improved help text and comments

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function                                             old     new   delta
packed_usage                                       24750   24787     +37
run                                                  658     655      -3
pick                                                  40      34      -6
arp                                                  186     177      -9
zcip_main                                           1402    1356     -46
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/4 up/down: 37/-64)            Total: -27 bytes
This commit is contained in:
Denis Vlasenko 2008-10-10 11:28:39 +00:00
parent afd7a8d744
commit cdd1f732bc
2 changed files with 83 additions and 63 deletions
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5
include/usage.h
View File

@ -4680,8 +4680,11 @@
"Manage a ZeroConf IPv4 link-local address\n" \ "Manage a ZeroConf IPv4 link-local address\n" \
"\nOptions:" \ "\nOptions:" \
"\n -f Run in foreground" \ "\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 -r 169.254.x.x Request this address first" \
"\n -v Verbose" \ "\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__ */ #endif /* __BB_USAGE_H__ */

139
networking/zcip.c
View File

@ -75,35 +75,40 @@ enum {
}; };
struct globals { struct globals {
char *intf;
struct sockaddr saddr; struct sockaddr saddr;
struct ether_addr eth_addr;
}; };
#define G (*(struct globals*)&bb_common_bufsiz1) #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 * Pick a random link local IP address on 169.254/16, except that
* the first and last 256 addresses are reserved. * the first and last 256 addresses are reserved.
*/ */
static void pick(struct in_addr *ip) static uint32_t pick(void)
{ {
unsigned tmp; unsigned tmp;
do { do {
tmp = rand() & IN_CLASSB_HOST; tmp = rand() & IN_CLASSB_HOST;
} while (tmp > (IN_CLASSB_HOST - 0x0200)); } while (tmp > (IN_CLASSB_HOST - 0x0200));
ip->s_addr = htonl((LINKLOCAL_ADDR + 0x0100) + tmp); return htonl((LINKLOCAL_ADDR + 0x0100) + tmp);
} }
/** /**
* Broadcast an ARP packet. * Broadcast an ARP packet.
*/ */
static void arp(int op, static void arp(
const struct ether_addr *source_eth, struct in_addr source_ip, /* 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) const struct ether_addr *target_eth, struct in_addr target_ip)
{ {
enum { op = ARPOP_REQUEST };
#define source_eth (&eth_addr)
struct arp_packet p; struct arp_packet p;
memset(&p, 0, sizeof(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)); memcpy(&p.arp.arp_tpa, &target_ip, sizeof(p.arp.arp_tpa));
// send it // 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)); xsendto(sock_fd, &p, sizeof(p), &saddr, sizeof(saddr));
#undef source_eth
// Currently all callers ignore errors, that's why returns are
// commented out...
//return 0;
} }
/** /**
* 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; int status;
char *addr = addr; /* for gcc */ char *addr = addr; /* for gcc */
const char *fmt = "%s %s %s" + 3; 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) { if (ip) {
addr = inet_ntoa(*ip); addr = inet_ntoa(*ip);
xsetenv("ip", addr); xsetenv("ip", addr);
fmt -= 3; 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) { 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; return -errno;
} }
if (status != 0) 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; 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) MAIN_EXTERNALLY_VISIBLE;
int zcip_main(int argc, char **argv) int zcip_main(int argc, char **argv)
{ {
int state = PROBE; int state;
struct ether_addr eth_addr;
char *r_opt; char *r_opt;
unsigned opts; unsigned opts;
@ -184,7 +194,6 @@ int zcip_main(int argc, char **argv)
const struct ether_addr null_addr; const struct ether_addr null_addr;
struct in_addr ip; struct in_addr ip;
struct ifreq ifr; struct ifreq ifr;
char *script_av[3];
int timeout_ms; /* must be signed */ int timeout_ms; /* must be signed */
unsigned conflicts; unsigned conflicts;
unsigned nprobes; unsigned nprobes;
@ -196,7 +205,6 @@ int zcip_main(int argc, char **argv)
#define null_addr (L.null_addr ) #define null_addr (L.null_addr )
#define ip (L.ip ) #define ip (L.ip )
#define ifr (L.ifr ) #define ifr (L.ifr )
#define script_av (L.script_av )
#define timeout_ms (L.timeout_ms) #define timeout_ms (L.timeout_ms)
#define conflicts (L.conflicts ) #define conflicts (L.conflicts )
#define nprobes (L.nprobes ) #define nprobes (L.nprobes )
@ -234,29 +242,33 @@ int zcip_main(int argc, char **argv)
} }
} }
argc -= optind; argc -= optind;
argv += optind; argv += optind - 1;
intf = argv[0]; /* Now: argv[0]:junk argv[1]:intf argv[2]:script argv[3]:NULL */
script_av[0] = argv[1]; /* We need to make space for script argument: */
xsetenv("interface", intf); 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])
xsetenv("interface", argv_intf);
// initialize the interface (modprobe, ifup, etc) // initialize the interface (modprobe, ifup, etc)
script_av[1] = (char*)"init"; if (run(argv, "init", NULL))
if (run(script_av, NULL))
return EXIT_FAILURE; return EXIT_FAILURE;
// initialize saddr // initialize saddr
// saddr is: { u16 sa_family; u8 sa_data[14]; } // saddr is: { u16 sa_family; u8 sa_data[14]; }
//memset(&saddr, 0, sizeof(saddr)); //memset(&saddr, 0, sizeof(saddr));
//TODO: are we leaving sa_family == 0 (AF_UNSPEC)?! //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 // bind to the interface's ARP socket
xbind(sock_fd, &saddr, sizeof(saddr)); xbind(sock_fd, &saddr, sizeof(saddr));
// get the interface's ethernet address // get the interface's ethernet address
//memset(&ifr, 0, sizeof(ifr)); //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); xioctl(sock_fd, SIOCGIFHWADDR, &ifr);
memcpy(&eth_addr, &ifr.ifr_hwaddr.sa_data, ETH_ALEN); 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 // NOTE: the sequence of addresses we try changes only
// depending on when we detect conflicts. // depending on when we detect conflicts.
{ {
uint32_t t; uint32_t t = get_unaligned_u32p((uint32_t *) ((char *)&eth_addr + 2));
memcpy(&t, (char*)&eth_addr + 2, 4);
srand(t); srand(t);
} }
if (ip.s_addr == 0) if (ip.s_addr == 0)
pick(&ip); ip.s_addr = pick();
// FIXME cases to handle: // FIXME cases to handle:
// - zcip already running! // - zcip already running!
@ -283,7 +294,7 @@ int zcip_main(int argc, char **argv)
#if BB_MMU #if BB_MMU
bb_daemonize(0 /*was: DAEMON_CHDIR_ROOT*/); bb_daemonize(0 /*was: DAEMON_CHDIR_ROOT*/);
#endif #endif
bb_info_msg("start, interface %s", intf); bb_info_msg("start, interface %s", argv_intf);
} }
// run the dynamic address negotiation protocol, // run the dynamic address negotiation protocol,
@ -294,6 +305,14 @@ int zcip_main(int argc, char **argv)
// - arp announcements that we're claiming it // - arp announcements that we're claiming it
// - use it // - use it
// - defend it, within limits // - 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) { while (1) {
struct pollfd fds[1]; struct pollfd fds[1];
unsigned deadline_us; unsigned deadline_us;
@ -316,7 +335,7 @@ int zcip_main(int argc, char **argv)
deadline_us = MONOTONIC_US() + timeout_ms * 1000; deadline_us = MONOTONIC_US() + timeout_ms * 1000;
VDBG("...wait %d %s nprobes=%u, nclaims=%u\n", 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)) { switch (safe_poll(fds, 1, timeout_ms)) {
@ -334,9 +353,9 @@ int zcip_main(int argc, char **argv)
if (nprobes < PROBE_NUM) { if (nprobes < PROBE_NUM) {
nprobes++; nprobes++;
VDBG("probe/%u %s@%s\n", VDBG("probe/%u %s@%s\n",
nprobes, intf, inet_ntoa(ip)); nprobes, argv_intf, inet_ntoa(ip));
arp(ARPOP_REQUEST, arp(/* ARPOP_REQUEST, */
&eth_addr, null_ip, /* &eth_addr, */ null_ip,
&null_addr, ip); &null_addr, ip);
timeout_ms = PROBE_MIN * 1000; timeout_ms = PROBE_MIN * 1000;
timeout_ms += random_delay_ms(PROBE_MAX - PROBE_MIN); timeout_ms += random_delay_ms(PROBE_MAX - PROBE_MIN);
@ -346,9 +365,9 @@ int zcip_main(int argc, char **argv)
state = ANNOUNCE; state = ANNOUNCE;
nclaims = 0; nclaims = 0;
VDBG("announce/%u %s@%s\n", VDBG("announce/%u %s@%s\n",
nclaims, intf, inet_ntoa(ip)); nclaims, argv_intf, inet_ntoa(ip));
arp(ARPOP_REQUEST, arp(/* ARPOP_REQUEST, */
&eth_addr, ip, /* &eth_addr, */ ip,
&eth_addr, ip); &eth_addr, ip);
timeout_ms = ANNOUNCE_INTERVAL * 1000; timeout_ms = ANNOUNCE_INTERVAL * 1000;
} }
@ -359,9 +378,9 @@ int zcip_main(int argc, char **argv)
state = ANNOUNCE; state = ANNOUNCE;
nclaims = 0; nclaims = 0;
VDBG("announce/%u %s@%s\n", VDBG("announce/%u %s@%s\n",
nclaims, intf, inet_ntoa(ip)); nclaims, argv_intf, inet_ntoa(ip));
arp(ARPOP_REQUEST, arp(/* ARPOP_REQUEST, */
&eth_addr, ip, /* &eth_addr, */ ip,
&eth_addr, ip); &eth_addr, ip);
timeout_ms = ANNOUNCE_INTERVAL * 1000; timeout_ms = ANNOUNCE_INTERVAL * 1000;
break; break;
@ -371,9 +390,9 @@ int zcip_main(int argc, char **argv)
if (nclaims < ANNOUNCE_NUM) { if (nclaims < ANNOUNCE_NUM) {
nclaims++; nclaims++;
VDBG("announce/%u %s@%s\n", VDBG("announce/%u %s@%s\n",
nclaims, intf, inet_ntoa(ip)); nclaims, argv_intf, inet_ntoa(ip));
arp(ARPOP_REQUEST, arp(/* ARPOP_REQUEST, */
&eth_addr, ip, /* &eth_addr, */ ip,
&eth_addr, ip); &eth_addr, ip);
timeout_ms = ANNOUNCE_INTERVAL * 1000; timeout_ms = ANNOUNCE_INTERVAL * 1000;
} }
@ -382,8 +401,7 @@ int zcip_main(int argc, char **argv)
state = MONITOR; state = MONITOR;
// link is ok to use earlier // link is ok to use earlier
// FIXME update filters // FIXME update filters
script_av[1] = (char*)"config"; run(argv, "config", &ip);
run(script_av, &ip);
ready = 1; ready = 1;
conflicts = 0; conflicts = 0;
timeout_ms = -1; // Never timeout in the monitor state. timeout_ms = -1; // Never timeout in the monitor state.
@ -403,7 +421,7 @@ int zcip_main(int argc, char **argv)
default: default:
// Invalid, should never happen. Restart the whole protocol. // Invalid, should never happen. Restart the whole protocol.
state = PROBE; state = PROBE;
pick(&ip); ip.s_addr = pick();
timeout_ms = 0; timeout_ms = 0;
nprobes = 0; nprobes = 0;
nclaims = 0; nclaims = 0;
@ -432,10 +450,9 @@ int zcip_main(int argc, char **argv)
if (fds[0].revents & POLLERR) { if (fds[0].revents & POLLERR) {
// FIXME: links routinely go down; // FIXME: links routinely go down;
// this shouldn't necessarily exit. // this shouldn't necessarily exit.
bb_error_msg("iface %s is down", intf); bb_error_msg("iface %s is down", argv_intf);
if (ready) { if (ready) {
script_av[1] = (char*)"deconfig"; run(argv, "deconfig", &ip);
run(script_av, &ip);
} }
return EXIT_FAILURE; 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 *spa = (struct in_addr *) p.arp.arp_spa;
struct in_addr *tpa = (struct in_addr *) p.arp.arp_tpa; struct in_addr *tpa = (struct in_addr *) p.arp.arp_tpa;
VDBG("%s recv arp type=%d, op=%d,\n", 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)); ntohs(p.arp.arp_op));
VDBG("\tsource=%s %s\n", VDBG("\tsource=%s %s\n",
ether_ntoa(sha), ether_ntoa(sha),
@ -494,13 +511,13 @@ int zcip_main(int argc, char **argv)
if (source_ip_conflict || target_ip_conflict) { if (source_ip_conflict || target_ip_conflict) {
conflicts++; conflicts++;
if (conflicts >= MAX_CONFLICTS) { if (conflicts >= MAX_CONFLICTS) {
VDBG("%s ratelimit\n", intf); VDBG("%s ratelimit\n", argv_intf);
timeout_ms = RATE_LIMIT_INTERVAL * 1000; timeout_ms = RATE_LIMIT_INTERVAL * 1000;
state = RATE_LIMIT_PROBE; state = RATE_LIMIT_PROBE;
} }
// restart the whole protocol // restart the whole protocol
pick(&ip); ip.s_addr = pick();
timeout_ms = 0; timeout_ms = 0;
nprobes = 0; nprobes = 0;
nclaims = 0; nclaims = 0;
@ -512,8 +529,8 @@ int zcip_main(int argc, char **argv)
VDBG("monitor conflict -- defending\n"); VDBG("monitor conflict -- defending\n");
state = DEFEND; state = DEFEND;
timeout_ms = DEFEND_INTERVAL * 1000; timeout_ms = DEFEND_INTERVAL * 1000;
arp(ARPOP_REQUEST, arp(/* ARPOP_REQUEST, */
&eth_addr, ip, /* &eth_addr, */ ip,
&eth_addr, ip); &eth_addr, ip);
} }
break; break;
@ -523,11 +540,10 @@ int zcip_main(int argc, char **argv)
state = PROBE; state = PROBE;
VDBG("defend conflict -- starting over\n"); VDBG("defend conflict -- starting over\n");
ready = 0; ready = 0;
script_av[1] = (char*)"deconfig"; run(argv, "deconfig", &ip);
run(script_av, &ip);
// restart the whole protocol // restart the whole protocol
pick(&ip); ip.s_addr = pick();
timeout_ms = 0; timeout_ms = 0;
nprobes = 0; nprobes = 0;
nclaims = 0; nclaims = 0;
@ -537,7 +553,7 @@ int zcip_main(int argc, char **argv)
// Invalid, should never happen. Restart the whole protocol. // Invalid, should never happen. Restart the whole protocol.
VDBG("invalid state -- starting over\n"); VDBG("invalid state -- starting over\n");
state = PROBE; state = PROBE;
pick(&ip); ip.s_addr = pick();
timeout_ms = 0; timeout_ms = 0;
nprobes = 0; nprobes = 0;
nclaims = 0; nclaims = 0;
@ -546,4 +562,5 @@ int zcip_main(int argc, char **argv)
break; // case 1 (packets arriving) break; // case 1 (packets arriving)
} // switch poll } // switch poll
} // while (1) } // while (1)
#undef argv_intf
} }