From cdd1f732bc5b8447dd12b59613663b7d08fce20b Mon Sep 17 00:00:00 2001 From: Denis Vlasenko Date: Fri, 10 Oct 2008 11:28:39 +0000 Subject: 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 --- include/usage.h | 5 +- networking/zcip.c | 141 ++++++++++++++++++++++++++++++------------------------ 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 ð_addr */ + struct in_addr source_ip, const struct ether_addr *target_eth, struct in_addr target_ip) { + enum { op = ARPOP_REQUEST }; +#define source_eth (ð_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(ð_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*)ð_addr + 2, 4); + uint32_t t = get_unaligned_u32p((uint32_t *) ((char *)ð_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 "