X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=networking%2Fzcip.c;h=fccb1a466d3376f68f0ffca3829f3478efb5e48c;hb=3da5572bfa81a63ce66e41b99e9801c47a05bbbf;hp=c50d5abafef60884e53ab813c1d4f7b6ec6af265;hpb=cad04ef4f3435e56181a81c896912543be34ea3c;p=oweals%2Fbusybox.git diff --git a/networking/zcip.c b/networking/zcip.c index c50d5abaf..fccb1a466 100644 --- a/networking/zcip.c +++ b/networking/zcip.c @@ -23,21 +23,21 @@ // - avoid silent script failures, especially under load... // - link status monitoring (restart on link-up; stop on link-down) -#include "busybox.h" -#include -#include -#include #include #include #include #include - #include #include +#include "libbb.h" +#include + +/* We don't need more than 32 bits of the counter */ +#define MONOTONIC_US() ((unsigned)monotonic_us()) struct arp_packet { - struct ether_header hdr; + struct ether_header eth; struct ether_arp arp; } ATTRIBUTE_PACKED; @@ -67,12 +67,21 @@ enum { DEFEND }; -#define VDBG(fmt,args...) \ - do { } while (0) +#define VDBG(...) do { } while (0) + + +enum { + sock_fd = 3 +}; + +struct globals { + char *intf; + struct sockaddr saddr; +}; +#define G (*(struct globals*)&bb_common_bufsiz1) +#define intf (G.intf ) +#define saddr (G.saddr) -static unsigned opts; -#define FOREGROUND (opts & 1) -#define QUIT (opts & 2) /** * Pick a random link local IP address on 169.254/16, except that @@ -82,29 +91,26 @@ static void pick(struct in_addr *ip) { unsigned tmp; - /* use cheaper math than lrand48() mod N */ do { - tmp = (lrand48() >> 16) & IN_CLASSB_HOST; + tmp = rand() & IN_CLASSB_HOST; } while (tmp > (IN_CLASSB_HOST - 0x0200)); ip->s_addr = htonl((LINKLOCAL_ADDR + 0x0100) + tmp); } -/* TODO: we need a flag to direct bb_[p]error_msg output to stderr. */ - /** * Broadcast an ARP packet. */ -static void arp(int fd, struct sockaddr *saddr, int op, - const struct ether_addr *source_addr, struct in_addr source_ip, - const struct ether_addr *target_addr, struct in_addr target_ip) +static void arp(int op, + const struct ether_addr *source_eth, struct in_addr source_ip, + const struct ether_addr *target_eth, struct in_addr target_ip) { struct arp_packet p; memset(&p, 0, sizeof(p)); // ether header - p.hdr.ether_type = htons(ETHERTYPE_ARP); - memcpy(p.hdr.ether_shost, source_addr, ETH_ALEN); - memset(p.hdr.ether_dhost, 0xff, ETH_ALEN); + p.eth.ether_type = htons(ETHERTYPE_ARP); + memcpy(p.eth.ether_shost, source_eth, ETH_ALEN); + memset(p.eth.ether_dhost, 0xff, ETH_ALEN); // arp request p.arp.arp_hrd = htons(ARPHRD_ETHER); @@ -112,113 +118,113 @@ static void arp(int fd, struct sockaddr *saddr, int op, p.arp.arp_hln = ETH_ALEN; p.arp.arp_pln = 4; p.arp.arp_op = htons(op); - memcpy(&p.arp.arp_sha, source_addr, ETH_ALEN); + memcpy(&p.arp.arp_sha, source_eth, ETH_ALEN); memcpy(&p.arp.arp_spa, &source_ip, sizeof(p.arp.arp_spa)); - memcpy(&p.arp.arp_tha, target_addr, ETH_ALEN); + memcpy(&p.arp.arp_tha, target_eth, ETH_ALEN); memcpy(&p.arp.arp_tpa, &target_ip, sizeof(p.arp.arp_tpa)); // send it - if (sendto(fd, &p, sizeof(p), 0, saddr, sizeof(*saddr)) < 0) { - bb_perror_msg("sendto"); - //return -errno; - } + xsendto(sock_fd, &p, sizeof(p), &saddr, sizeof(saddr)); + // Currently all callers ignore errors, that's why returns are // commented out... //return 0; } /** - * Run a script. + * Run a script. argv[2] is already NULL. */ -static int run(const char *script, const char *arg, const char *intf, struct in_addr *ip) +static int run(char *argv[3], struct in_addr *ip) { - int pid, status; - const char *why; - - if(1) { //always true: if (script != NULL) - VDBG("%s run %s %s\n", intf, script, arg); - if (ip != NULL) { - char *addr = inet_ntoa(*ip); - setenv("ip", addr, 1); - bb_info_msg("%s %s %s", arg, intf, addr); - } + int status; + char *addr = addr; /* for gcc */ + const char *fmt = "%s %s %s" + 3; - pid = vfork(); - if (pid < 0) { // error - why = "vfork"; - goto bad; - } else if (pid == 0) { // child - execl(script, script, arg, NULL); - bb_perror_msg("execl"); - _exit(EXIT_FAILURE); - } + VDBG("%s run %s %s\n", intf, argv[0], argv[1]); - if (waitpid(pid, &status, 0) <= 0) { - why = "waitpid"; - goto bad; - } - if (WEXITSTATUS(status) != 0) { - bb_error_msg("script %s failed, exit=%d", - script, WEXITSTATUS(status)); - return -errno; - } + if (ip) { + addr = inet_ntoa(*ip); + setenv("ip", addr, 1); + fmt -= 3; + } + bb_info_msg(fmt, argv[1], intf, addr); + + status = wait4pid(spawn(argv)); + if (status < 0) { + bb_perror_msg("%s %s %s" + 3, argv[1], intf); + return -errno; } - return 0; -bad: - status = -errno; - bb_perror_msg("%s %s, %s", arg, intf, why); + if (status != 0) + bb_error_msg("script %s %s failed, exitcode=%d", argv[0], argv[1], status); return status; } - /** * Return milliseconds of random delay, up to "secs" seconds. */ -static unsigned ATTRIBUTE_ALWAYS_INLINE ms_rdelay(unsigned secs) +static ALWAYS_INLINE unsigned random_delay_ms(unsigned secs) { - return lrand48() % (secs * 1000); + return rand() % (secs * 1000); } /** * main program */ - -/* Used to be auto variables on main() stack, but - * most of them were zero-inited. Moving them to bss - * is more space-efficient. - */ -static const struct in_addr null_ip; // = { 0 }; -static const struct ether_addr null_addr; // = { {0, 0, 0, 0, 0, 0} }; - -static struct sockaddr saddr; // memset(0); -static struct in_addr ip; // = { 0 }; -static struct ifreq ifr; //memset(0); - -static char *intf; // = NULL; -static char *script; // = NULL; -static suseconds_t timeout; // = 0; // milliseconds -static unsigned conflicts; // = 0; -static unsigned nprobes; // = 0; -static unsigned nclaims; // = 0; -static int ready; // = 0; -static int verbose; // = 0; -static int state = PROBE; - -int zcip_main(int argc, char *argv[]); -int zcip_main(int argc, char *argv[]) +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; - const char *why; - int fd; + char *r_opt; + unsigned opts; + + // ugly trick, but I want these zeroed in one go + struct { + const struct in_addr null_ip; + 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; + unsigned nclaims; + int ready; + int verbose; + } L; +#define null_ip (L.null_ip ) +#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 ) +#define nclaims (L.nclaims ) +#define ready (L.ready ) +#define verbose (L.verbose ) + + memset(&L, 0, sizeof(L)); +#define FOREGROUND (opts & 1) +#define QUIT (opts & 2) // parse commandline: prog [options] ifname script - char *r_opt; - opt_complementary = "vv:vf"; // -v accumulates and implies -f - opts = getopt32(argc, argv, "fqr:v", &r_opt, &verbose); + // exactly 2 args; -v accumulates and implies -f + opt_complementary = "=2:vv:vf"; + opts = getopt32(argv, "fqr:v", &r_opt, &verbose); +#if !BB_MMU + // on NOMMU reexec early (or else we will rerun things twice) + if (!FOREGROUND) + bb_daemonize_or_rexec(0 /*was: DAEMON_CHDIR_ROOT*/, argv); +#endif + // open an ARP socket + // (need to do it before openlog to prevent openlog from taking + // fd 3 (sock_fd==3)) + xmove_fd(xsocket(AF_PACKET, SOCK_PACKET, htons(ETH_P_ARP)), sock_fd); if (!FOREGROUND) { - /* Do it early, before all bb_xx_msg calls */ - logmode = LOGMODE_SYSLOG; + // do it before all bb_xx_msg calls openlog(applet_name, 0, LOG_DAEMON); + logmode |= LOGMODE_SYSLOG; } if (opts & 4) { // -r n.n.n.n if (inet_aton(r_opt, &ip) == 0 @@ -229,39 +235,42 @@ int zcip_main(int argc, char *argv[]) } argc -= optind; argv += optind; - if (argc != 2) - bb_show_usage(); + intf = argv[0]; - script = argv[1]; + script_av[0] = argv[1]; setenv("interface", intf, 1); // initialize the interface (modprobe, ifup, etc) - if (run(script, "init", intf, NULL) < 0) + script_av[1] = (char*)"init"; + if (run(script_av, 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)); - // open an ARP socket - fd = xsocket(PF_PACKET, SOCK_PACKET, htons(ETH_P_ARP)); // bind to the interface's ARP socket - xbind(fd, &saddr, sizeof(saddr)); + 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)); - if (ioctl(fd, SIOCGIFHWADDR, &ifr) < 0) { - bb_perror_msg_and_die("get ethernet address"); - } + xioctl(sock_fd, SIOCGIFHWADDR, &ifr); memcpy(ð_addr, &ifr.ifr_hwaddr.sa_data, ETH_ALEN); // start with some stable ip address, either a function of // the hardware address or else the last address we used. + // we are taking low-order four bytes, as top-order ones + // aren't random enough. // NOTE: the sequence of addresses we try changes only // depending on when we detect conflicts. - // (SVID 3 bogon: who says that "short" is always 16 bits?) - seed48( (unsigned short*)&ifr.ifr_hwaddr.sa_data ); + { + uint32_t t; + memcpy(&t, (char*)ð_addr + 2, 4); + srand(t); + } if (ip.s_addr == 0) pick(&ip); @@ -271,9 +280,9 @@ int zcip_main(int argc, char *argv[]) // daemonize now; don't delay system startup if (!FOREGROUND) { - /* bb_daemonize(); - bad, will close fd! */ -//NOMMU - xdaemon(0, 0); +#if BB_MMU + bb_daemonize(0 /*was: DAEMON_CHDIR_ROOT*/); +#endif bb_info_msg("start, interface %s", intf); } @@ -281,41 +290,39 @@ int zcip_main(int argc, char *argv[]) // restarting after address conflicts: // - start with some address we want to try // - short random delay - // - arp probes to see if another host else uses it + // - arp probes to see if another host uses it // - arp announcements that we're claiming it // - use it // - defend it, within limits while (1) { struct pollfd fds[1]; - struct timeval tv1; + unsigned deadline_us; struct arp_packet p; + int source_ip_conflict; + int target_ip_conflict; - int source_ip_conflict = 0; - int target_ip_conflict = 0; - - fds[0].fd = fd; + fds[0].fd = sock_fd; fds[0].events = POLLIN; fds[0].revents = 0; // poll, being ready to adjust current timeout - if (!timeout) { - timeout = ms_rdelay(PROBE_WAIT); - // FIXME setsockopt(fd, SO_ATTACH_FILTER, ...) to + if (!timeout_ms) { + timeout_ms = random_delay_ms(PROBE_WAIT); + // FIXME setsockopt(sock_fd, SO_ATTACH_FILTER, ...) to // make the kernel filter out all packets except // ones we'd care about. } - // set tv1 to the point in time when we timeout - gettimeofday(&tv1, NULL); - tv1.tv_usec += (timeout % 1000) * 1000; - while (tv1.tv_usec > 1000000) { - tv1.tv_usec -= 1000000; - tv1.tv_sec++; - } - tv1.tv_sec += timeout / 1000; + // set deadline_us to the point in time when we timeout + deadline_us = MONOTONIC_US() + timeout_ms * 1000; + + VDBG("...wait %d %s nprobes=%u, nclaims=%u\n", + timeout_ms, intf, nprobes, nclaims); + + switch (safe_poll(fds, 1, timeout_ms)) { - VDBG("...wait %ld %s nprobes=%d, nclaims=%d\n", - timeout, intf, nprobes, nclaims); - switch (poll(fds, 1, timeout)) { + default: + //bb_perror_msg("poll"); - done in safe_poll + return EXIT_FAILURE; // timeout case 0: @@ -326,25 +333,24 @@ int zcip_main(int argc, char *argv[]) // have been received, so we can progress through the states if (nprobes < PROBE_NUM) { nprobes++; - VDBG("probe/%d %s@%s\n", + VDBG("probe/%u %s@%s\n", nprobes, intf, inet_ntoa(ip)); - arp(fd, &saddr, ARPOP_REQUEST, + arp(ARPOP_REQUEST, ð_addr, null_ip, &null_addr, ip); - timeout = PROBE_MIN * 1000; - timeout += ms_rdelay(PROBE_MAX - - PROBE_MIN); + timeout_ms = PROBE_MIN * 1000; + timeout_ms += random_delay_ms(PROBE_MAX - PROBE_MIN); } else { // Switch to announce state. state = ANNOUNCE; nclaims = 0; - VDBG("announce/%d %s@%s\n", + VDBG("announce/%u %s@%s\n", nclaims, intf, inet_ntoa(ip)); - arp(fd, &saddr, ARPOP_REQUEST, + arp(ARPOP_REQUEST, ð_addr, ip, ð_addr, ip); - timeout = ANNOUNCE_INTERVAL * 1000; + timeout_ms = ANNOUNCE_INTERVAL * 1000; } break; case RATE_LIMIT_PROBE: @@ -352,34 +358,35 @@ int zcip_main(int argc, char *argv[]) // have been received, so we can move immediately to the announce state state = ANNOUNCE; nclaims = 0; - VDBG("announce/%d %s@%s\n", + VDBG("announce/%u %s@%s\n", nclaims, intf, inet_ntoa(ip)); - arp(fd, &saddr, ARPOP_REQUEST, + arp(ARPOP_REQUEST, ð_addr, ip, ð_addr, ip); - timeout = ANNOUNCE_INTERVAL * 1000; + timeout_ms = ANNOUNCE_INTERVAL * 1000; break; case ANNOUNCE: // timeouts in the ANNOUNCE state mean no conflicting ARP packets // have been received, so we can progress through the states if (nclaims < ANNOUNCE_NUM) { nclaims++; - VDBG("announce/%d %s@%s\n", + VDBG("announce/%u %s@%s\n", nclaims, intf, inet_ntoa(ip)); - arp(fd, &saddr, ARPOP_REQUEST, + arp(ARPOP_REQUEST, ð_addr, ip, ð_addr, ip); - timeout = ANNOUNCE_INTERVAL * 1000; + timeout_ms = ANNOUNCE_INTERVAL * 1000; } else { // Switch to monitor state. state = MONITOR; // link is ok to use earlier // FIXME update filters - run(script, "config", intf, &ip); + script_av[1] = (char*)"config"; + run(script_av, &ip); ready = 1; conflicts = 0; - timeout = -1; // Never timeout in the monitor state. + timeout_ms = -1; // Never timeout in the monitor state. // NOTE: all other exit paths // should deconfig ... @@ -390,37 +397,34 @@ int zcip_main(int argc, char *argv[]) case DEFEND: // We won! No ARP replies, so just go back to monitor. state = MONITOR; - timeout = -1; + timeout_ms = -1; conflicts = 0; break; default: // Invalid, should never happen. Restart the whole protocol. state = PROBE; pick(&ip); - timeout = 0; + timeout_ms = 0; nprobes = 0; nclaims = 0; break; } // switch (state) break; // case 0 (timeout) - // packets arriving + + // packets arriving, or link went down case 1: // We need to adjust the timeout in case we didn't receive // a conflicting packet. - if (timeout > 0) { - struct timeval tv2; - - gettimeofday(&tv2, NULL); - if (timercmp(&tv1, &tv2, <)) { + if (timeout_ms > 0) { + unsigned diff = deadline_us - MONOTONIC_US(); + if ((int)(diff) < 0) { // Current time is greater than the expected timeout time. // Should never happen. VDBG("missed an expected timeout\n"); - timeout = 0; + timeout_ms = 0; } else { VDBG("adjusting timeout\n"); - timersub(&tv1, &tv2, &tv1); - timeout = 1000 * tv1.tv_sec - + tv1.tv_usec / 1000; + timeout_ms = (diff / 1000) | 1; /* never 0 */ } } @@ -428,10 +432,10 @@ 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("%s: poll error", intf); + bb_error_msg("iface %s is down", intf); if (ready) { - run(script, "deconfig", - intf, &ip); + script_av[1] = (char*)"deconfig"; + run(script_av, &ip); } return EXIT_FAILURE; } @@ -439,21 +443,19 @@ int zcip_main(int argc, char *argv[]) } // read ARP packet - if (recv(fd, &p, sizeof(p), 0) < 0) { - why = "recv"; - goto bad; + if (safe_read(sock_fd, &p, sizeof(p)) < 0) { + bb_perror_msg_and_die(bb_msg_read_error); } - if (p.hdr.ether_type != htons(ETHERTYPE_ARP)) + if (p.eth.ether_type != htons(ETHERTYPE_ARP)) continue; - #ifdef DEBUG { - struct ether_addr * sha = (struct ether_addr *) p.arp.arp_sha; - struct ether_addr * tha = (struct ether_addr *) p.arp.arp_tha; - struct in_addr * spa = (struct in_addr *) p.arp.arp_spa; - struct in_addr * tpa = (struct in_addr *) p.arp.arp_tpa; + struct ether_addr *sha = (struct ether_addr *) p.arp.arp_sha; + struct ether_addr *tha = (struct ether_addr *) p.arp.arp_tha; + 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.hdr.ether_type), + intf, ntohs(p.eth.ether_type), ntohs(p.arp.arp_op)); VDBG("\tsource=%s %s\n", ether_ntoa(sha), @@ -464,16 +466,21 @@ int zcip_main(int argc, char *argv[]) } #endif if (p.arp.arp_op != htons(ARPOP_REQUEST) - && p.arp.arp_op != htons(ARPOP_REPLY)) + && p.arp.arp_op != htons(ARPOP_REPLY)) continue; - if (memcmp(p.arp.arp_spa, &ip.s_addr, sizeof(struct in_addr)) == 0 && - memcmp(ð_addr, &p.arp.arp_sha, ETH_ALEN) != 0) { + source_ip_conflict = 0; + target_ip_conflict = 0; + + if (memcmp(p.arp.arp_spa, &ip.s_addr, sizeof(struct in_addr)) == 0 + && memcmp(&p.arp.arp_sha, ð_addr, ETH_ALEN) != 0 + ) { source_ip_conflict = 1; } - if (memcmp(p.arp.arp_tpa, &ip.s_addr, sizeof(struct in_addr)) == 0 && - p.arp.arp_op == htons(ARPOP_REQUEST) && - memcmp(ð_addr, &p.arp.arp_tha, ETH_ALEN) != 0) { + if (p.arp.arp_op == htons(ARPOP_REQUEST) + && memcmp(p.arp.arp_tpa, &ip.s_addr, sizeof(struct in_addr)) == 0 + && memcmp(&p.arp.arp_tha, ð_addr, ETH_ALEN) != 0 + ) { target_ip_conflict = 1; } @@ -488,13 +495,13 @@ int zcip_main(int argc, char *argv[]) conflicts++; if (conflicts >= MAX_CONFLICTS) { VDBG("%s ratelimit\n", intf); - timeout = RATE_LIMIT_INTERVAL * 1000; + timeout_ms = RATE_LIMIT_INTERVAL * 1000; state = RATE_LIMIT_PROBE; } // restart the whole protocol pick(&ip); - timeout = 0; + timeout_ms = 0; nprobes = 0; nclaims = 0; } @@ -504,11 +511,10 @@ int zcip_main(int argc, char *argv[]) if (source_ip_conflict) { VDBG("monitor conflict -- defending\n"); state = DEFEND; - timeout = DEFEND_INTERVAL * 1000; - arp(fd, &saddr, - ARPOP_REQUEST, - ð_addr, ip, - ð_addr, ip); + timeout_ms = DEFEND_INTERVAL * 1000; + arp(ARPOP_REQUEST, + ð_addr, ip, + ð_addr, ip); } break; case DEFEND: @@ -517,11 +523,12 @@ int zcip_main(int argc, char *argv[]) state = PROBE; VDBG("defend conflict -- starting over\n"); ready = 0; - run(script, "deconfig", intf, &ip); + script_av[1] = (char*)"deconfig"; + run(script_av, &ip); // restart the whole protocol pick(&ip); - timeout = 0; + timeout_ms = 0; nprobes = 0; nclaims = 0; } @@ -531,19 +538,12 @@ int zcip_main(int argc, char *argv[]) VDBG("invalid state -- starting over\n"); state = PROBE; pick(&ip); - timeout = 0; + timeout_ms = 0; nprobes = 0; nclaims = 0; break; } // switch state - break; // case 1 (packets arriving) - default: - why = "poll"; - goto bad; } // switch poll - } -bad: - bb_perror_msg("%s, %s", intf, why); - return EXIT_FAILURE; + } // while (1) }