zcip: code size optimizations, improved help text and comments
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
parent
afd7a8d744
commit
cdd1f732bc
@ -4680,8 +4680,11 @@
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"Manage a ZeroConf IPv4 link-local address\n" \
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"\nOptions:" \
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"\n -f Run in foreground" \
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"\n -q Quit after address (no daemon)" \
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"\n -q Quit after obtaining address" \
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"\n -r 169.254.x.x Request this address first" \
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"\n -v Verbose" \
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"\n" \
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"\nWith no -q, runs continuously monitoring for ARP conflicts," \
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"\nexits only on I/O errors (link down etc)" \
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#endif /* __BB_USAGE_H__ */
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@ -75,35 +75,40 @@ enum {
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};
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struct globals {
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char *intf;
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struct sockaddr saddr;
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struct ether_addr eth_addr;
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};
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#define G (*(struct globals*)&bb_common_bufsiz1)
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#define intf (G.intf )
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#define saddr (G.saddr)
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#define saddr (G.saddr )
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#define eth_addr (G.eth_addr)
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/**
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* Pick a random link local IP address on 169.254/16, except that
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* the first and last 256 addresses are reserved.
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*/
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static void pick(struct in_addr *ip)
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static uint32_t pick(void)
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{
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unsigned tmp;
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do {
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tmp = rand() & IN_CLASSB_HOST;
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} while (tmp > (IN_CLASSB_HOST - 0x0200));
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ip->s_addr = htonl((LINKLOCAL_ADDR + 0x0100) + tmp);
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return htonl((LINKLOCAL_ADDR + 0x0100) + tmp);
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}
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/**
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* Broadcast an ARP packet.
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*/
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static void arp(int op,
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const struct ether_addr *source_eth, struct in_addr source_ip,
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static void arp(
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/* int op, - always ARPOP_REQUEST */
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/* const struct ether_addr *source_eth, - always ð_addr */
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struct in_addr source_ip,
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const struct ether_addr *target_eth, struct in_addr target_ip)
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{
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enum { op = ARPOP_REQUEST };
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#define source_eth (ð_addr)
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struct arp_packet p;
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memset(&p, 0, sizeof(p));
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@ -124,38 +129,44 @@ static void arp(int op,
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memcpy(&p.arp.arp_tpa, &target_ip, sizeof(p.arp.arp_tpa));
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// send it
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// Even though sock_fd is already bound to saddr, just send()
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// won't work, because "socket is not connected"
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// (and connect() won't fix that, "operation not supported").
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// Thus we sendto() to saddr. I wonder which sockaddr
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// (from bind() or from sendto()?) kernel actually uses
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// to determine iface to emit the packet from...
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xsendto(sock_fd, &p, sizeof(p), &saddr, sizeof(saddr));
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// Currently all callers ignore errors, that's why returns are
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// commented out...
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//return 0;
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#undef source_eth
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}
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/**
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* Run a script. argv[2] is already NULL.
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* Run a script.
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* argv[0]:intf argv[1]:script_name argv[2]:junk argv[3]:NULL
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*/
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static int run(char *argv[3], struct in_addr *ip)
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static int run(char *argv[3], const char *param, struct in_addr *ip)
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{
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int status;
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char *addr = addr; /* for gcc */
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const char *fmt = "%s %s %s" + 3;
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VDBG("%s run %s %s\n", intf, argv[0], argv[1]);
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argv[2] = (char*)param;
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VDBG("%s run %s %s\n", argv[0], argv[1], argv[2]);
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if (ip) {
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addr = inet_ntoa(*ip);
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xsetenv("ip", addr);
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fmt -= 3;
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}
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bb_info_msg(fmt, argv[1], intf, addr);
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bb_info_msg(fmt, argv[2], argv[0], addr);
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status = wait4pid(spawn(argv));
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status = wait4pid(spawn(argv + 1));
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if (status < 0) {
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bb_perror_msg("%s %s %s" + 3, argv[1], intf);
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bb_perror_msg("%s %s %s" + 3, argv[2], argv[0]);
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return -errno;
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}
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if (status != 0)
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bb_error_msg("script %s %s failed, exitcode=%d", argv[0], argv[1], status);
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bb_error_msg("script %s %s failed, exitcode=%d", argv[1], argv[2], status);
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return status;
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}
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@ -173,8 +184,7 @@ static ALWAYS_INLINE unsigned random_delay_ms(unsigned secs)
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int zcip_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int zcip_main(int argc, char **argv)
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{
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int state = PROBE;
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struct ether_addr eth_addr;
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int state;
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char *r_opt;
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unsigned opts;
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@ -184,7 +194,6 @@ int zcip_main(int argc, char **argv)
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const struct ether_addr null_addr;
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struct in_addr ip;
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struct ifreq ifr;
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char *script_av[3];
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int timeout_ms; /* must be signed */
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unsigned conflicts;
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unsigned nprobes;
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@ -196,7 +205,6 @@ int zcip_main(int argc, char **argv)
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#define null_addr (L.null_addr )
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#define ip (L.ip )
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#define ifr (L.ifr )
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#define script_av (L.script_av )
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#define timeout_ms (L.timeout_ms)
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#define conflicts (L.conflicts )
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#define nprobes (L.nprobes )
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@ -234,29 +242,33 @@ int zcip_main(int argc, char **argv)
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}
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}
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argc -= optind;
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argv += optind;
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argv += optind - 1;
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intf = argv[0];
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script_av[0] = argv[1];
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xsetenv("interface", intf);
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/* Now: argv[0]:junk argv[1]:intf argv[2]:script argv[3]:NULL */
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/* We need to make space for script argument: */
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argv[0] = argv[1];
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argv[1] = argv[2];
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/* Now: argv[0]:intf argv[1]:script argv[2]:junk argv[3]:NULL */
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#define argv_intf (argv[0])
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xsetenv("interface", argv_intf);
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// initialize the interface (modprobe, ifup, etc)
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script_av[1] = (char*)"init";
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if (run(script_av, NULL))
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if (run(argv, "init", NULL))
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return EXIT_FAILURE;
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// initialize saddr
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// saddr is: { u16 sa_family; u8 sa_data[14]; }
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//memset(&saddr, 0, sizeof(saddr));
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//TODO: are we leaving sa_family == 0 (AF_UNSPEC)?!
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safe_strncpy(saddr.sa_data, intf, sizeof(saddr.sa_data));
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safe_strncpy(saddr.sa_data, argv_intf, sizeof(saddr.sa_data));
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// bind to the interface's ARP socket
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xbind(sock_fd, &saddr, sizeof(saddr));
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// get the interface's ethernet address
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//memset(&ifr, 0, sizeof(ifr));
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strncpy(ifr.ifr_name, intf, sizeof(ifr.ifr_name));
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strncpy(ifr.ifr_name, argv_intf, sizeof(ifr.ifr_name));
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xioctl(sock_fd, SIOCGIFHWADDR, &ifr);
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memcpy(ð_addr, &ifr.ifr_hwaddr.sa_data, ETH_ALEN);
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@ -267,12 +279,11 @@ int zcip_main(int argc, char **argv)
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// NOTE: the sequence of addresses we try changes only
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// depending on when we detect conflicts.
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{
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uint32_t t;
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memcpy(&t, (char*)ð_addr + 2, 4);
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uint32_t t = get_unaligned_u32p((uint32_t *) ((char *)ð_addr + 2));
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srand(t);
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}
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if (ip.s_addr == 0)
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pick(&ip);
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ip.s_addr = pick();
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// FIXME cases to handle:
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// - zcip already running!
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@ -283,7 +294,7 @@ int zcip_main(int argc, char **argv)
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#if BB_MMU
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bb_daemonize(0 /*was: DAEMON_CHDIR_ROOT*/);
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#endif
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bb_info_msg("start, interface %s", intf);
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bb_info_msg("start, interface %s", argv_intf);
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}
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// run the dynamic address negotiation protocol,
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@ -294,6 +305,14 @@ int zcip_main(int argc, char **argv)
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// - arp announcements that we're claiming it
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// - use it
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// - defend it, within limits
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// exit if:
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// - address is successfully obtained and -q was given:
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// run "<script> config", then exit with exitcode 0
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// - poll error (when does this happen?)
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// - read error (when does this happen?)
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// - sendto error (in arp()) (when does this happen?)
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// - revents & POLLERR (link down). run "<script> deconfig" first
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state = PROBE;
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while (1) {
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struct pollfd fds[1];
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unsigned deadline_us;
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@ -316,7 +335,7 @@ int zcip_main(int argc, char **argv)
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deadline_us = MONOTONIC_US() + timeout_ms * 1000;
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VDBG("...wait %d %s nprobes=%u, nclaims=%u\n",
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timeout_ms, intf, nprobes, nclaims);
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timeout_ms, argv_intf, nprobes, nclaims);
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switch (safe_poll(fds, 1, timeout_ms)) {
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@ -334,9 +353,9 @@ int zcip_main(int argc, char **argv)
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if (nprobes < PROBE_NUM) {
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nprobes++;
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VDBG("probe/%u %s@%s\n",
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nprobes, intf, inet_ntoa(ip));
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arp(ARPOP_REQUEST,
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ð_addr, null_ip,
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nprobes, argv_intf, inet_ntoa(ip));
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arp(/* ARPOP_REQUEST, */
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/* ð_addr, */ null_ip,
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&null_addr, ip);
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timeout_ms = PROBE_MIN * 1000;
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timeout_ms += random_delay_ms(PROBE_MAX - PROBE_MIN);
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@ -346,9 +365,9 @@ int zcip_main(int argc, char **argv)
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state = ANNOUNCE;
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nclaims = 0;
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VDBG("announce/%u %s@%s\n",
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nclaims, intf, inet_ntoa(ip));
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arp(ARPOP_REQUEST,
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ð_addr, ip,
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nclaims, argv_intf, inet_ntoa(ip));
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arp(/* ARPOP_REQUEST, */
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/* ð_addr, */ ip,
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ð_addr, ip);
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timeout_ms = ANNOUNCE_INTERVAL * 1000;
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}
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@ -359,9 +378,9 @@ int zcip_main(int argc, char **argv)
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state = ANNOUNCE;
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nclaims = 0;
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VDBG("announce/%u %s@%s\n",
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nclaims, intf, inet_ntoa(ip));
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arp(ARPOP_REQUEST,
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ð_addr, ip,
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nclaims, argv_intf, inet_ntoa(ip));
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arp(/* ARPOP_REQUEST, */
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/* ð_addr, */ ip,
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ð_addr, ip);
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timeout_ms = ANNOUNCE_INTERVAL * 1000;
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break;
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@ -371,9 +390,9 @@ int zcip_main(int argc, char **argv)
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if (nclaims < ANNOUNCE_NUM) {
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nclaims++;
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VDBG("announce/%u %s@%s\n",
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nclaims, intf, inet_ntoa(ip));
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arp(ARPOP_REQUEST,
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ð_addr, ip,
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nclaims, argv_intf, inet_ntoa(ip));
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arp(/* ARPOP_REQUEST, */
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/* ð_addr, */ ip,
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ð_addr, ip);
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timeout_ms = ANNOUNCE_INTERVAL * 1000;
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}
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@ -382,8 +401,7 @@ int zcip_main(int argc, char **argv)
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state = MONITOR;
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// link is ok to use earlier
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// FIXME update filters
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script_av[1] = (char*)"config";
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run(script_av, &ip);
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run(argv, "config", &ip);
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ready = 1;
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conflicts = 0;
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timeout_ms = -1; // Never timeout in the monitor state.
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@ -403,7 +421,7 @@ int zcip_main(int argc, char **argv)
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default:
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// Invalid, should never happen. Restart the whole protocol.
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state = PROBE;
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pick(&ip);
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ip.s_addr = pick();
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timeout_ms = 0;
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nprobes = 0;
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nclaims = 0;
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@ -432,10 +450,9 @@ int zcip_main(int argc, char **argv)
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if (fds[0].revents & POLLERR) {
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// FIXME: links routinely go down;
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// this shouldn't necessarily exit.
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bb_error_msg("iface %s is down", intf);
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bb_error_msg("iface %s is down", argv_intf);
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if (ready) {
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script_av[1] = (char*)"deconfig";
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run(script_av, &ip);
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run(argv, "deconfig", &ip);
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}
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return EXIT_FAILURE;
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}
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@ -455,7 +472,7 @@ int zcip_main(int argc, char **argv)
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struct in_addr *spa = (struct in_addr *) p.arp.arp_spa;
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struct in_addr *tpa = (struct in_addr *) p.arp.arp_tpa;
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VDBG("%s recv arp type=%d, op=%d,\n",
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intf, ntohs(p.eth.ether_type),
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argv_intf, ntohs(p.eth.ether_type),
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ntohs(p.arp.arp_op));
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VDBG("\tsource=%s %s\n",
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ether_ntoa(sha),
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@ -494,13 +511,13 @@ int zcip_main(int argc, char **argv)
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if (source_ip_conflict || target_ip_conflict) {
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conflicts++;
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if (conflicts >= MAX_CONFLICTS) {
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VDBG("%s ratelimit\n", intf);
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VDBG("%s ratelimit\n", argv_intf);
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timeout_ms = RATE_LIMIT_INTERVAL * 1000;
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state = RATE_LIMIT_PROBE;
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}
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// restart the whole protocol
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pick(&ip);
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ip.s_addr = pick();
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timeout_ms = 0;
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nprobes = 0;
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nclaims = 0;
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@ -512,8 +529,8 @@ int zcip_main(int argc, char **argv)
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VDBG("monitor conflict -- defending\n");
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state = DEFEND;
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timeout_ms = DEFEND_INTERVAL * 1000;
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arp(ARPOP_REQUEST,
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ð_addr, ip,
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arp(/* ARPOP_REQUEST, */
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/* ð_addr, */ ip,
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ð_addr, ip);
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}
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break;
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@ -523,11 +540,10 @@ int zcip_main(int argc, char **argv)
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state = PROBE;
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VDBG("defend conflict -- starting over\n");
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ready = 0;
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script_av[1] = (char*)"deconfig";
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run(script_av, &ip);
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run(argv, "deconfig", &ip);
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// restart the whole protocol
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pick(&ip);
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ip.s_addr = pick();
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timeout_ms = 0;
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nprobes = 0;
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nclaims = 0;
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@ -537,7 +553,7 @@ int zcip_main(int argc, char **argv)
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// Invalid, should never happen. Restart the whole protocol.
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VDBG("invalid state -- starting over\n");
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state = PROBE;
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pick(&ip);
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ip.s_addr = pick();
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timeout_ms = 0;
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nprobes = 0;
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nclaims = 0;
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@ -546,4 +562,5 @@ int zcip_main(int argc, char **argv)
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break; // case 1 (packets arriving)
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} // switch poll
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} // while (1)
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#undef argv_intf
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}
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