X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=networking%2Fzcip.c;h=5e10673779a77f7da1f536c49e97703444058c3d;hb=59fe8b90890a07c87ec9c2943bae515d5c6d959d;hp=de9ea7675dfca8168ac984e0a390aff486227079;hpb=8445a9ff99f04cad8845a1aed6ab17737f2d985a;p=oweals%2Fbusybox.git diff --git a/networking/zcip.c b/networking/zcip.c index de9ea7675..5e1067377 100644 --- a/networking/zcip.c +++ b/networking/zcip.c @@ -1,3 +1,4 @@ +/* vi: set sw=4 ts=4: */ /* * RFC3927 ZeroConf IPv4 Link-Local addressing * (see ) @@ -5,55 +6,32 @@ * Copyright (C) 2003 by Arthur van Hoff (avh@strangeberry.com) * Copyright (C) 2004 by David Brownell * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or - * (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA - * 02111-1307 USA + * Licensed under the GPL v2 or later, see the file LICENSE in this tarball. */ /* - * This can build as part of BusyBox or by itself: - * - * $(CROSS_COMPILE)cc -Os -Wall -DNO_BUSYBOX -DDEBUG -o zcip zcip.c - * * ZCIP just manages the 169.254.*.* addresses. That network is not * routed at the IP level, though various proxies or bridges can * certainly be used. Its naming is built over multicast DNS. */ -/* TODO: - - more real-world usage/testing, especially daemon mode - - kernel packet filters to reduce scheduling noise - - avoid silent script failures, especially under load... - - link status monitoring (restart on link-up; stop on link-down) -*/ +// #define DEBUG + +// TODO: +// - more real-world usage/testing, especially daemon mode +// - kernel packet filters to reduce scheduling noise +// - 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 #include -#include -#include -#include -#include #include #include #include @@ -61,46 +39,49 @@ #include #include -#include "busybox.h" -#include "libbb.h" + struct arp_packet { struct ether_header hdr; - /* FIXME this part is netinet/if_ether.h "struct ether_arp" */ + // FIXME this part is netinet/if_ether.h "struct ether_arp" struct arphdr arp; struct ether_addr source_addr; struct in_addr source_ip; struct ether_addr target_addr; struct in_addr target_ip; -} __attribute__ ((__packed__)); +} ATTRIBUTE_PACKED; +enum { /* 169.254.0.0 */ -static const uint32_t LINKLOCAL_ADDR = 0xa9fe0000; + LINKLOCAL_ADDR = 0xa9fe0000, /* protocol timeout parameters, specified in seconds */ -static const unsigned PROBE_WAIT = 1; -static const unsigned PROBE_MIN = 1; -static const unsigned PROBE_MAX = 2; -static const unsigned PROBE_NUM = 3; -static const unsigned MAX_CONFLICTS = 10; -static const unsigned RATE_LIMIT_INTERVAL = 60; -static const unsigned ANNOUNCE_WAIT = 2; -static const unsigned ANNOUNCE_NUM = 2; -static const unsigned ANNOUNCE_INTERVAL = 2; -static const time_t DEFEND_INTERVAL = 10; - -#define ZCIP_VERSION "0.75 (18 April 2005)" + PROBE_WAIT = 1, + PROBE_MIN = 1, + PROBE_MAX = 2, + PROBE_NUM = 3, + MAX_CONFLICTS = 10, + RATE_LIMIT_INTERVAL = 60, + ANNOUNCE_WAIT = 2, + ANNOUNCE_NUM = 2, + ANNOUNCE_INTERVAL = 2, + DEFEND_INTERVAL = 10 +}; static const struct in_addr null_ip = { 0 }; static const struct ether_addr null_addr = { {0, 0, 0, 0, 0, 0} }; +static int verbose = 0; -/* +#define DBG(fmt,args...) \ + do { } while (0) +#define VDBG DBG + +/** * 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 void pick(struct in_addr *ip) { unsigned tmp; @@ -111,22 +92,21 @@ pick(struct in_addr *ip) ip->s_addr = htonl((LINKLOCAL_ADDR + 0x0100) + tmp); } -/* +/** * Broadcast an ARP packet. */ -static int -arp(int fd, struct sockaddr *saddr, int op, +static int 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) { struct arp_packet p; - /* ether header */ + // 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); - /* arp request */ + // arp request p.arp.ar_hrd = htons(ARPHRD_ETHER); p.arp.ar_pro = htons(ETHERTYPE_IP); p.arp.ar_hln = ETH_ALEN; @@ -137,45 +117,47 @@ arp(int fd, struct sockaddr *saddr, int op, memcpy(&p.target_addr, target_addr, ETH_ALEN); memcpy(&p.target_ip, &target_ip, sizeof (p.target_ip)); - /* send it */ + // send it if (sendto(fd, &p, sizeof (p), 0, saddr, sizeof (*saddr)) < 0) { - bb_perror_msg("sendto"); + perror("sendto"); return -errno; } return 0; } -/* +/** * Run a script. */ -static int -run(char *script, char *arg, char *intf, struct in_addr *ip) +static int run(char *script, char *arg, char *intf, struct in_addr *ip) { int pid, status; char *why; if (script != NULL) { + VDBG("%s run %s %s\n", intf, script, arg); if (ip != NULL) { char *addr = inet_ntoa(*ip); - xsetenv("ip", addr); + setenv("ip", addr, 1); syslog(LOG_INFO, "%s %s %s", arg, intf, addr); } pid = vfork(); - if (pid < 0) { /* error */ + if (pid < 0) { // error why = "vfork"; goto bad; - } else if (pid == 0) { /* child */ + } else if (pid == 0) { // child execl(script, script, arg, NULL); - bb_perror_msg_and_die("execl"); - } + perror("execl"); + _exit(EXIT_FAILURE); + } if (waitpid(pid, &status, 0) <= 0) { why = "waitpid"; goto bad; } if (WEXITSTATUS(status) != 0) { - bb_perror_msg("script %s failed, exit=%d", script, WEXITSTATUS(status)); + bb_error_msg("script %s failed, exit=%d\n", + script, WEXITSTATUS(status)); return -errno; } } @@ -187,89 +169,96 @@ bad: return status; } -/* + +/** * Return milliseconds of random delay, up to "secs" seconds. */ -static inline unsigned -ms_rdelay(unsigned secs) +static inline unsigned ms_rdelay(unsigned secs) { return lrand48() % (secs * 1000); } -/* +/** * main program */ -#define FOREGROUND 1 -#define QUIT 2 -#define REQUEST 4 -#define VERBOSE 8 - int zcip_main(int argc, char *argv[]) { char *intf = NULL; char *script = NULL; + int quit = 0; + int foreground = 0; + char *why; struct sockaddr saddr; struct ether_addr addr; struct in_addr ip = { 0 }; int fd; int ready = 0; - suseconds_t timeout = 0; /* milliseconds */ + suseconds_t timeout = 0; // milliseconds time_t defend = 0; unsigned conflicts = 0; unsigned nprobes = 0; unsigned nclaims = 0; - unsigned long t; - - bb_opt_complementaly = "vf"; - /* parse commandline: prog [options] ifname script */ - t = bb_getopt_ulflags(argc, argv, "fqr:v", &why); /* reuse char* why */ - - argc -= optind; - argv += optind; - - if ((t & 0x80000000UL) || (argc < 1) || (argc > 2)) { - bb_show_usage(); - } - - if (t & VERBOSE) { - bb_printf("%s: version %s\n", bb_applet_name, ZCIP_VERSION); + int t; + + // parse commandline: prog [options] ifname script + while ((t = getopt(argc, argv, "fqr:v")) != EOF) { + switch (t) { + case 'f': + foreground = 1; + continue; + case 'q': + quit = 1; + continue; + case 'r': + if (inet_aton(optarg, &ip) == 0 + || (ntohl(ip.s_addr) & IN_CLASSB_NET) + != LINKLOCAL_ADDR) { + bb_error_msg_and_die("invalid link address"); + } + continue; + case 'v': + verbose++; + foreground = 1; + continue; + default: + bb_error_msg_and_die("bad option"); + } } - if ((t & REQUEST) && (inet_aton(why, &ip) == 0 || (ntohl(ip.s_addr) & IN_CLASSB_NET) != LINKLOCAL_ADDR)) { - bb_perror_msg_and_die("invalid link address"); + if (optind < argc - 1) { + intf = argv[optind++]; + setenv("interface", intf, 1); + script = argv[optind++]; } - - intf = argv[0]; - xsetenv("interface", intf); - script = argv[1]; /* Could be NULL ? */ - + if (optind != argc || !intf) + bb_show_usage(); openlog(bb_applet_name, 0, LOG_DAEMON); - /* initialize the interface (modprobe, ifup, etc) */ + // initialize the interface (modprobe, ifup, etc) if (run(script, "init", intf, NULL) < 0) return EXIT_FAILURE; - /* initialize saddr */ + // initialize saddr memset(&saddr, 0, sizeof (saddr)); - strncpy(saddr.sa_data, intf, sizeof (saddr.sa_data)); + safe_strncpy(saddr.sa_data, intf, sizeof (saddr.sa_data)); - /* open an ARP socket */ + // open an ARP socket if ((fd = socket(PF_PACKET, SOCK_PACKET, htons(ETH_P_ARP))) < 0) { why = "open"; fail: - t |= FOREGROUND; + foreground = 1; goto bad; } - /* bind to the interface's ARP socket */ + // bind to the interface's ARP socket if (bind(fd, &saddr, sizeof (saddr)) < 0) { why = "bind"; goto fail; } else { struct ifreq ifr; - short seed[3]; + unsigned short seed[3]; - /* get the interface's ethernet address */ + // 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) { @@ -278,37 +267,37 @@ fail: } memcpy(&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. - NOTE: the sequence of addresses we try changes only - depending on when we detect conflicts. */ + // start with some stable ip address, either a function of + // the hardware address or else the last address we used. + // NOTE: the sequence of addresses we try changes only + // depending on when we detect conflicts. memcpy(seed, &ifr.ifr_hwaddr.sa_data, ETH_ALEN); seed48(seed); if (ip.s_addr == 0) pick(&ip); } - /* FIXME cases to handle: - - zcip already running! - - link already has local address... just defend/update */ + // FIXME cases to handle: + // - zcip already running! + // - link already has local address... just defend/update - /* daemonize now; don't delay system startup */ - if (!(t & FOREGROUND)) { - if (daemon(0, (t & VERBOSE)) < 0) { + // daemonize now; don't delay system startup + if (!foreground) { + if (daemon(0, verbose) < 0) { why = "daemon"; goto bad; } syslog(LOG_INFO, "start, interface %s", intf); } - /* run the dynamic address negotiation protocol, - 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 announcements that we're claiming it - - use it - - defend it, within limits */ + // run the dynamic address negotiation protocol, + // 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 announcements that we're claiming it + // - use it + // - defend it, within limits while (1) { struct pollfd fds[1]; struct timeval tv1; @@ -318,28 +307,32 @@ fail: fds[0].events = POLLIN; fds[0].revents = 0; - /* poll, being ready to adjust current timeout */ - if (timeout > 0) { - 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; - } else if (timeout == 0) { + // poll, being ready to adjust current timeout + if (!timeout) { timeout = ms_rdelay(PROBE_WAIT); - /* FIXME setsockopt(fd, SO_ATTACH_FILTER, ...) to - make the kernel filter out all packets except - ones we'd care about. */ + // FIXME setsockopt(fd, SO_ATTACH_FILTER, ...) to + // make the kernel filter out all packets except + // ones we'd care about. } + 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; + + VDBG("...wait %ld %s nprobes=%d, nclaims=%d\n", + timeout, intf, nprobes, nclaims); switch (poll(fds, 1, timeout)) { - /* timeouts trigger protocol transitions */ + // timeouts trigger protocol transitions case 0: - /* probes */ + // probes if (nprobes < PROBE_NUM) { nprobes++; + VDBG("probe/%d %s@%s\n", + nprobes, intf, inet_ntoa(ip)); (void)arp(fd, &saddr, ARPOP_REQUEST, &addr, null_ip, &null_addr, ip); @@ -350,39 +343,41 @@ fail: } else timeout = ANNOUNCE_WAIT * 1000; } - /* then announcements */ + // then announcements else if (nclaims < ANNOUNCE_NUM) { nclaims++; + VDBG("announce/%d %s@%s\n", + nclaims, intf, inet_ntoa(ip)); (void)arp(fd, &saddr, ARPOP_REQUEST, &addr, ip, &addr, ip); if (nclaims < ANNOUNCE_NUM) { timeout = ANNOUNCE_INTERVAL * 1000; } else { - /* link is ok to use earlier */ + // link is ok to use earlier run(script, "config", intf, &ip); ready = 1; conflicts = 0; timeout = -1; - /* NOTE: all other exit paths - should deconfig ... */ - if (t & QUIT) + // NOTE: all other exit paths + // should deconfig ... + if (quit) return EXIT_SUCCESS; - /* FIXME update filters */ + // FIXME update filters } } break; - /* packets arriving */ + // packets arriving case 1: - /* maybe adjust timeout */ + // maybe adjust timeout if (timeout > 0) { struct timeval tv2; - + gettimeofday(&tv2, NULL); if (timercmp(&tv1, &tv2, <)) { - timeout = -1; + timeout = 0; } else { timersub(&tv1, &tv2, &tv1); timeout = 1000 * tv1.tv_sec @@ -391,33 +386,45 @@ fail: } if ((fds[0].revents & POLLIN) == 0) { if (fds[0].revents & POLLERR) { - /* FIXME: links routinely go down; - this shouldn't necessarily exit. */ - bb_perror_msg("%s: poll error", intf); + // FIXME: links routinely go down; + // this shouldn't necessarily exit. + bb_error_msg("%s: poll error\n", intf); if (ready) { - run(script, "deconfig", intf, &ip); + run(script, "deconfig", + intf, &ip); } return EXIT_FAILURE; } continue; } - /* read ARP packet */ + // read ARP packet if (recv(fd, &p, sizeof (p), 0) < 0) { why = "recv"; goto bad; } if (p.hdr.ether_type != htons(ETHERTYPE_ARP)) continue; - + + VDBG("%s recv arp type=%d, op=%d,\n", + intf, ntohs(p.hdr.ether_type), + ntohs(p.arp.ar_op)); + VDBG("\tsource=%s %s\n", + ether_ntoa(&p.source_addr), + inet_ntoa(p.source_ip)); + VDBG("\ttarget=%s %s\n", + ether_ntoa(&p.target_addr), + inet_ntoa(p.target_ip)); if (p.arp.ar_op != htons(ARPOP_REQUEST) && p.arp.ar_op != htons(ARPOP_REPLY)) continue; - /* some cases are always conflicts */ + // some cases are always conflicts if ((p.source_ip.s_addr == ip.s_addr) && (memcmp(&addr, &p.source_addr, ETH_ALEN) != 0)) { collision: + VDBG("%s ARP conflict from %s\n", intf, + ether_ntoa(&p.source_addr)); if (ready) { time_t now = time(0); @@ -428,26 +435,28 @@ collision: ARPOP_REQUEST, &addr, ip, &addr, ip); + VDBG("%s defend\n", intf); timeout = -1; continue; } defend = now; ready = 0; run(script, "deconfig", intf, &ip); - /* FIXME rm filters: setsockopt(fd, - SO_DETACH_FILTER, ...) */ + // FIXME rm filters: setsockopt(fd, + // SO_DETACH_FILTER, ...) } conflicts++; if (conflicts >= MAX_CONFLICTS) { + VDBG("%s ratelimit\n", intf); sleep(RATE_LIMIT_INTERVAL); } - /* restart the whole protocol */ + // restart the whole protocol pick(&ip); timeout = 0; nprobes = 0; nclaims = 0; } - /* two hosts probing one address is a collision too */ + // two hosts probing one address is a collision too else if (p.target_ip.s_addr == ip.s_addr && nclaims == 0 && p.arp.ar_op == htons(ARPOP_REQUEST) @@ -463,11 +472,10 @@ collision: } } bad: - if ( t & FOREGROUND) { - bb_perror_msg(why); - } else { + if (foreground) + perror(why); + else syslog(LOG_ERR, "%s %s, %s error: %s", bb_applet_name, intf, why, strerror(errno)); - } return EXIT_FAILURE; }