/* $OpenBSD: ifstated.c,v 1.39 2011/03/15 08:38:07 okan Exp $ */ /* * Copyright (c) 2004 Marco Pfatschbacher * Copyright (c) 2004 Ryan McBride * * Permission to use, copy, modify, and distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies. * * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ /* * ifstated listens to link_state transitions on interfaces * and executes predefined commands. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "ifstated.h" struct ifsd_config *conf = NULL, *newconf = NULL; int opts = 0; int opt_inhibit = 0; char *configfile = "/etc/ifstated.conf"; struct event rt_msg_ev, sighup_ev, startup_ev, sigchld_ev; void startup_handler(int, short, void *); void sighup_handler(int, short, void *); int load_config(void); void sigchld_handler(int, short, void *); void rt_msg_handler(int, short, void *); void external_handler(int, short, void *); void external_exec(struct ifsd_external *, int); void check_external_status(struct ifsd_state *); void external_evtimer_setup(struct ifsd_state *, int); void scan_ifstate(int, int, int); int scan_ifstate_single(int, int, struct ifsd_state *); void fetch_state(void); void usage(void); void adjust_expressions(struct ifsd_expression_list *, int); void adjust_external_expressions(struct ifsd_state *); void eval_state(struct ifsd_state *); int state_change(void); void do_action(struct ifsd_action *); void remove_action(struct ifsd_action *, struct ifsd_state *); void remove_expression(struct ifsd_expression *, struct ifsd_state *); void usage(void) { extern char *__progname; fprintf(stderr, "usage: %s [-dhinv] [-D macro=value] [-f file]\n", __progname); exit(1); } int main(int argc, char *argv[]) { struct timeval tv; int ch; int debug = 0; log_init(1); while ((ch = getopt(argc, argv, "dD:f:hniv")) != -1) { switch (ch) { case 'd': debug = 1; break; case 'D': if (cmdline_symset(optarg) < 0) errx(1, "could not parse macro definition %s", optarg); break; case 'f': configfile = optarg; break; case 'h': usage(); break; case 'n': opts |= IFSD_OPT_NOACTION; break; case 'i': opt_inhibit = 1; break; case 'v': if (opts & IFSD_OPT_VERBOSE) opts |= IFSD_OPT_VERBOSE2; opts |= IFSD_OPT_VERBOSE; break; default: usage(); } } argc -= optind; argv += optind; if (argc > 0) usage(); if (opts & IFSD_OPT_NOACTION) { if ((newconf = parse_config(configfile, opts)) == NULL) exit(1); warnx("configuration OK"); exit(0); } if (!debug) daemon(1, 0); event_init(); log_init(debug); signal_set(&sigchld_ev, SIGCHLD, sigchld_handler, NULL); signal_add(&sigchld_ev, NULL); /* Loading the config needs to happen in the event loop */ timerclear(&tv); evtimer_set(&startup_ev, startup_handler, NULL); evtimer_add(&startup_ev, &tv); event_loop(0); exit(0); } void startup_handler(int fd, short event, void *arg) { int rt_fd; unsigned int rtfilter; if ((rt_fd = socket(PF_ROUTE, SOCK_RAW, 0)) < 0) err(1, "no routing socket"); if (load_config() != 0) { log_warnx("unable to load config"); exit(1); } rtfilter = ROUTE_FILTER(RTM_IFINFO); if (setsockopt(rt_fd, PF_ROUTE, ROUTE_MSGFILTER, &rtfilter, sizeof(rtfilter)) == -1) /* not fatal */ log_warn("startup_handler: setsockopt"); event_set(&rt_msg_ev, rt_fd, EV_READ|EV_PERSIST, rt_msg_handler, NULL); event_add(&rt_msg_ev, NULL); signal_set(&sighup_ev, SIGHUP, sighup_handler, NULL); signal_add(&sighup_ev, NULL); log_info("started"); } void sighup_handler(int fd, short event, void *arg) { log_info("reloading config"); if (load_config() != 0) log_warnx("unable to reload config"); } int load_config(void) { if ((newconf = parse_config(configfile, opts)) == NULL) return (-1); if (conf != NULL) clear_config(conf); conf = newconf; conf->always.entered = time(NULL); fetch_state(); external_evtimer_setup(&conf->always, IFSD_EVTIMER_ADD); adjust_external_expressions(&conf->always); eval_state(&conf->always); if (conf->curstate != NULL) { log_info("initial state: %s", conf->curstate->name); conf->curstate->entered = time(NULL); conf->nextstate = conf->curstate; conf->curstate = NULL; while (state_change()) do_action(conf->curstate->always); } return (0); } void rt_msg_handler(int fd, short event, void *arg) { char msg[2048]; struct rt_msghdr *rtm = (struct rt_msghdr *)&msg; struct if_msghdr ifm; int len; len = read(fd, msg, sizeof(msg)); /* XXX ignore errors? */ if (len < sizeof(struct rt_msghdr)) return; if (rtm->rtm_version != RTM_VERSION) return; if (rtm->rtm_type != RTM_IFINFO) return; memcpy(&ifm, rtm, sizeof(ifm)); scan_ifstate(ifm.ifm_index, ifm.ifm_data.ifi_link_state, 1); } void sigchld_handler(int fd, short event, void *arg) { check_external_status(&conf->always); if (conf->curstate != NULL) check_external_status(conf->curstate); } void external_handler(int fd, short event, void *arg) { struct ifsd_external *external = (struct ifsd_external *)arg; struct timeval tv; /* re-schedule */ timerclear(&tv); tv.tv_sec = external->frequency; evtimer_set(&external->ev, external_handler, external); evtimer_add(&external->ev, &tv); /* execute */ external_exec(external, 1); } void external_exec(struct ifsd_external *external, int async) { char *argp[] = {"sh", "-c", NULL, NULL}; pid_t pid; int s; if (external->pid > 0) { log_debug("previous command %s [%d] still running, killing it", external->command, external->pid); kill(external->pid, SIGKILL); waitpid(external->pid, &s, 0); external->pid = 0; } argp[2] = external->command; log_debug("running %s", external->command); pid = fork(); if (pid < 0) { log_warn("fork error"); } else if (pid == 0) { execv("/bin/sh", argp); _exit(1); /* NOTREACHED */ } else { external->pid = pid; } if (!async) { waitpid(external->pid, &s, 0); external->pid = 0; if (WIFEXITED(s)) external->prevstatus = WEXITSTATUS(s); } } void adjust_external_expressions(struct ifsd_state *state) { struct ifsd_external *external; struct ifsd_expression_list expressions; TAILQ_INIT(&expressions); TAILQ_FOREACH(external, &state->external_tests, entries) { struct ifsd_expression *expression; if (external->prevstatus == -1) continue; TAILQ_FOREACH(expression, &external->expressions, entries) { TAILQ_INSERT_TAIL(&expressions, expression, eval); expression->truth = !external->prevstatus; } adjust_expressions(&expressions, conf->maxdepth); } } void check_external_status(struct ifsd_state *state) { struct ifsd_external *external, *end = NULL; int status, s, changed = 0; /* Do this manually; change ordering so the oldest is first */ external = TAILQ_FIRST(&state->external_tests); while (external != NULL && external != end) { struct ifsd_external *newexternal; newexternal = TAILQ_NEXT(external, entries); if (external->pid <= 0) goto loop; if (wait4(external->pid, &s, WNOHANG, NULL) == 0) goto loop; external->pid = 0; if (end == NULL) end = external; if (WIFEXITED(s)) status = WEXITSTATUS(s); else { log_warnx("%s exited abnormally", external->command); goto loop; } if (external->prevstatus != status && (external->prevstatus != -1 || !opt_inhibit)) { changed = 1; external->prevstatus = status; } external->lastexec = time(NULL); TAILQ_REMOVE(&state->external_tests, external, entries); TAILQ_INSERT_TAIL(&state->external_tests, external, entries); loop: external = newexternal; } if (changed) { adjust_external_expressions(state); eval_state(state); } } void external_evtimer_setup(struct ifsd_state *state, int action) { struct ifsd_external *external; int s; if (state != NULL) { switch (action) { case IFSD_EVTIMER_ADD: TAILQ_FOREACH(external, &state->external_tests, entries) { struct timeval tv; /* run it once right away */ external_exec(external, 0); /* schedule it for later */ timerclear(&tv); tv.tv_sec = external->frequency; evtimer_set(&external->ev, external_handler, external); evtimer_add(&external->ev, &tv); } break; case IFSD_EVTIMER_DEL: TAILQ_FOREACH(external, &state->external_tests, entries) { if (external->pid > 0) { kill(external->pid, SIGKILL); waitpid(external->pid, &s, 0); external->pid = 0; } evtimer_del(&external->ev); } break; } } } #define LINK_STATE_IS_DOWN(_s) \ (!LINK_STATE_IS_UP((_s)) && (_s) != LINK_STATE_UNKNOWN) int scan_ifstate_single(int ifindex, int s, struct ifsd_state *state) { struct ifsd_ifstate *ifstate; struct ifsd_expression_list expressions; int changed = 0; TAILQ_INIT(&expressions); TAILQ_FOREACH(ifstate, &state->interface_states, entries) { if (ifstate->ifindex == ifindex) { if (ifstate->prevstate != s && (ifstate->prevstate != -1 || !opt_inhibit)) { struct ifsd_expression *expression; int truth; truth = (ifstate->ifstate == IFSD_LINKUNKNOWN && s == LINK_STATE_UNKNOWN) || (ifstate->ifstate == IFSD_LINKDOWN && LINK_STATE_IS_DOWN(s)) || (ifstate->ifstate == IFSD_LINKUP && LINK_STATE_IS_UP(s)); TAILQ_FOREACH(expression, &ifstate->expressions, entries) { expression->truth = truth; TAILQ_INSERT_TAIL(&expressions, expression, eval); changed = 1; } ifstate->prevstate = s; } } } if (changed) adjust_expressions(&expressions, conf->maxdepth); return (changed); } void scan_ifstate(int ifindex, int s, int do_eval) { struct ifsd_state *state; int cur_eval = 0; if (scan_ifstate_single(ifindex, s, &conf->always) && do_eval) eval_state(&conf->always); TAILQ_FOREACH(state, &conf->states, entries) { if (scan_ifstate_single(ifindex, s, state) && (do_eval && state == conf->curstate)) cur_eval = 1; } /* execute actions _after_ all expressions have been adjusted */ if (cur_eval) eval_state(conf->curstate); } /* * Do a bottom-up ajustment of the expression tree's truth value, * level-by-level to ensure that each expression's subexpressions have been * evaluated. */ void adjust_expressions(struct ifsd_expression_list *expressions, int depth) { struct ifsd_expression_list nexpressions; struct ifsd_expression *expression; TAILQ_INIT(&nexpressions); while ((expression = TAILQ_FIRST(expressions)) != NULL) { TAILQ_REMOVE(expressions, expression, eval); if (expression->depth == depth) { struct ifsd_expression *te; switch (expression->type) { case IFSD_OPER_AND: expression->truth = expression->left->truth && expression->right->truth; break; case IFSD_OPER_OR: expression->truth = expression->left->truth || expression->right->truth; break; case IFSD_OPER_NOT: expression->truth = !expression->right->truth; break; default: break; } if (expression->parent != NULL) { if (TAILQ_EMPTY(&nexpressions)) te = NULL; TAILQ_FOREACH(te, &nexpressions, eval) if (expression->parent == te) break; if (te == NULL) TAILQ_INSERT_TAIL(&nexpressions, expression->parent, eval); } } else TAILQ_INSERT_TAIL(&nexpressions, expression, eval); } if (depth > 0) adjust_expressions(&nexpressions, depth - 1); } void eval_state(struct ifsd_state *state) { struct ifsd_external *external = TAILQ_FIRST(&state->external_tests); if (external == NULL || external->lastexec >= state->entered || external->lastexec == 0) { do_action(state->always); while (state_change()) do_action(conf->curstate->always); } } /* *If a previous action included a state change, process it. */ int state_change(void) { if (conf->nextstate != NULL && conf->curstate != conf->nextstate) { log_info("changing state to %s", conf->nextstate->name); if (conf->curstate != NULL) { evtimer_del(&conf->curstate->ev); external_evtimer_setup(conf->curstate, IFSD_EVTIMER_DEL); } conf->curstate = conf->nextstate; conf->nextstate = NULL; conf->curstate->entered = time(NULL); external_evtimer_setup(conf->curstate, IFSD_EVTIMER_ADD); adjust_external_expressions(conf->curstate); do_action(conf->curstate->init); return (1); } return (0); } /* * Run recursively through the tree of actions. */ void do_action(struct ifsd_action *action) { struct ifsd_action *subaction; switch (action->type) { case IFSD_ACTION_COMMAND: log_debug("running %s", action->act.command); system(action->act.command); break; case IFSD_ACTION_CHANGESTATE: conf->nextstate = action->act.nextstate; break; case IFSD_ACTION_CONDITION: if ((action->act.c.expression != NULL && action->act.c.expression->truth) || action->act.c.expression == NULL) { TAILQ_FOREACH(subaction, &action->act.c.actions, entries) do_action(subaction); } break; default: log_debug("do_action: unknown action %d", action->type); break; } } /* * Fetch the current link states. */ void fetch_state(void) { struct ifaddrs *ifap, *ifa; char *oname = NULL; int sock = socket(AF_INET, SOCK_DGRAM, 0); if (getifaddrs(&ifap) != 0) err(1, "getifaddrs"); for (ifa = ifap; ifa; ifa = ifa->ifa_next) { struct ifreq ifr; struct if_data ifrdat; if (oname && !strcmp(oname, ifa->ifa_name)) continue; oname = ifa->ifa_name; strlcpy(ifr.ifr_name, ifa->ifa_name, sizeof(ifr.ifr_name)); ifr.ifr_data = (caddr_t)&ifrdat; if (ioctl(sock, SIOCGIFDATA, (caddr_t)&ifr) == -1) continue; scan_ifstate(if_nametoindex(ifa->ifa_name), ifrdat.ifi_link_state, 0); } freeifaddrs(ifap); close(sock); } /* * Clear the config. */ void clear_config(struct ifsd_config *oconf) { struct ifsd_state *state; external_evtimer_setup(&conf->always, IFSD_EVTIMER_DEL); if (conf != NULL && conf->curstate != NULL) external_evtimer_setup(conf->curstate, IFSD_EVTIMER_DEL); while ((state = TAILQ_FIRST(&oconf->states)) != NULL) { TAILQ_REMOVE(&oconf->states, state, entries); remove_action(state->init, state); remove_action(state->always, state); free(state->name); free(state); } remove_action(oconf->always.init, &oconf->always); remove_action(oconf->always.always, &oconf->always); free(oconf); } void remove_action(struct ifsd_action *action, struct ifsd_state *state) { struct ifsd_action *subaction; if (action == NULL || state == NULL) return; switch (action->type) { case IFSD_ACTION_LOG: free(action->act.logmessage); break; case IFSD_ACTION_COMMAND: free(action->act.command); break; case IFSD_ACTION_CHANGESTATE: break; case IFSD_ACTION_CONDITION: if (action->act.c.expression != NULL) remove_expression(action->act.c.expression, state); while ((subaction = TAILQ_FIRST(&action->act.c.actions)) != NULL) { TAILQ_REMOVE(&action->act.c.actions, subaction, entries); remove_action(subaction, state); } } free(action); } void remove_expression(struct ifsd_expression *expression, struct ifsd_state *state) { switch (expression->type) { case IFSD_OPER_IFSTATE: TAILQ_REMOVE(&expression->u.ifstate->expressions, expression, entries); if (--expression->u.ifstate->refcount == 0) { TAILQ_REMOVE(&state->interface_states, expression->u.ifstate, entries); free(expression->u.ifstate); } break; case IFSD_OPER_EXTERNAL: TAILQ_REMOVE(&expression->u.external->expressions, expression, entries); if (--expression->u.external->refcount == 0) { TAILQ_REMOVE(&state->external_tests, expression->u.external, entries); free(expression->u.external->command); event_del(&expression->u.external->ev); free(expression->u.external); } break; default: if (expression->left != NULL) remove_expression(expression->left, state); if (expression->right != NULL) remove_expression(expression->right, state); break; } free(expression); }