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-rw-r--r--include/usage.h5
-rw-r--r--networking/zcip.c141
2 files changed, 83 insertions, 63 deletions
diff --git a/include/usage.h b/include/usage.h
index 8f6013e..d247864 100644
--- a/include/usage.h
+++ b/include/usage.h
@@ -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__ */
diff --git a/networking/zcip.c b/networking/zcip.c
index f406b6c..ff9c83d 100644
--- a/networking/zcip.c
+++ b/networking/zcip.c
@@ -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
}
generated by cgit v1.1 at 2024-12-27 13:17:38 +0000