/* $OpenBSD: pf_if.c,v 1.82 2015/11/20 03:35:23 dlg Exp $ */ /* * Copyright 2005 Henning Brauer * Copyright 2005 Ryan McBride * Copyright (c) 2001 Daniel Hartmeier * Copyright (c) 2003 Cedric Berger * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * - Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * - Redistributions in binary form must reproduce the above * copyright notice, this list of conditions and the following * disclaimer in the documentation and/or other materials provided * with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef INET6 #include #endif /* INET6 */ struct pfi_kif *pfi_all = NULL; struct pool pfi_addr_pl; struct pfi_ifhead pfi_ifs; long pfi_update = 1; struct pfr_addr *pfi_buffer; int pfi_buffer_cnt; int pfi_buffer_max; void pfi_kif_update(struct pfi_kif *); void pfi_dynaddr_update(struct pfi_dynaddr *dyn); void pfi_table_update(struct pfr_ktable *, struct pfi_kif *, u_int8_t, int); void pfi_kifaddr_update(void *); void pfi_instance_add(struct ifnet *, u_int8_t, int); void pfi_address_add(struct sockaddr *, sa_family_t, u_int8_t); int pfi_if_compare(struct pfi_kif *, struct pfi_kif *); int pfi_skip_if(const char *, struct pfi_kif *); int pfi_unmask(void *); RB_PROTOTYPE(pfi_ifhead, pfi_kif, pfik_tree, pfi_if_compare); RB_GENERATE(pfi_ifhead, pfi_kif, pfik_tree, pfi_if_compare); #define PFI_BUFFER_MAX 0x10000 #define PFI_MTYPE M_IFADDR void pfi_initialize(void) { if (pfi_all != NULL) /* already initialized */ return; pool_init(&pfi_addr_pl, sizeof(struct pfi_dynaddr), 0, 0, 0, "pfiaddrpl", NULL); pfi_buffer_max = 64; pfi_buffer = mallocarray(pfi_buffer_max, sizeof(*pfi_buffer), PFI_MTYPE, M_WAITOK); if ((pfi_all = pfi_kif_get(IFG_ALL)) == NULL) panic("pfi_kif_get for pfi_all failed"); } struct pfi_kif * pfi_kif_find(const char *kif_name) { struct pfi_kif_cmp s; bzero(&s, sizeof(s)); strlcpy(s.pfik_name, kif_name, sizeof(s.pfik_name)); return (RB_FIND(pfi_ifhead, &pfi_ifs, (struct pfi_kif *)&s)); } struct pfi_kif * pfi_kif_get(const char *kif_name) { struct pfi_kif *kif; if ((kif = pfi_kif_find(kif_name))) return (kif); /* create new one */ if ((kif = malloc(sizeof(*kif), PFI_MTYPE, M_NOWAIT|M_ZERO)) == NULL) return (NULL); strlcpy(kif->pfik_name, kif_name, sizeof(kif->pfik_name)); kif->pfik_tzero = time_second; TAILQ_INIT(&kif->pfik_dynaddrs); if (!strcmp(kif->pfik_name, "any")) { /* both so it works in the ioctl and the regular case */ kif->pfik_flags |= PFI_IFLAG_ANY; kif->pfik_flags_new |= PFI_IFLAG_ANY; } RB_INSERT(pfi_ifhead, &pfi_ifs, kif); return (kif); } void pfi_kif_ref(struct pfi_kif *kif, enum pfi_kif_refs what) { switch (what) { case PFI_KIF_REF_RULE: kif->pfik_rules++; break; case PFI_KIF_REF_STATE: kif->pfik_states++; break; case PFI_KIF_REF_ROUTE: kif->pfik_routes++; break; default: panic("pfi_kif_ref with unknown type"); } } void pfi_kif_unref(struct pfi_kif *kif, enum pfi_kif_refs what) { if (kif == NULL) return; switch (what) { case PFI_KIF_REF_NONE: break; case PFI_KIF_REF_RULE: if (kif->pfik_rules <= 0) { DPFPRINTF(LOG_ERR, "pfi_kif_unref: rules refcount <= 0"); return; } kif->pfik_rules--; break; case PFI_KIF_REF_STATE: if (kif->pfik_states <= 0) { DPFPRINTF(LOG_ERR, "pfi_kif_unref: state refcount <= 0"); return; } kif->pfik_states--; break; case PFI_KIF_REF_ROUTE: if (kif->pfik_routes <= 0) { DPFPRINTF(LOG_ERR, "pfi_kif_unref: state refcount <= 0"); return; } kif->pfik_routes--; break; default: panic("pfi_kif_unref with unknown type"); } if (kif->pfik_ifp != NULL || kif->pfik_group != NULL || kif == pfi_all) return; if (kif->pfik_rules || kif->pfik_states || kif->pfik_routes) return; RB_REMOVE(pfi_ifhead, &pfi_ifs, kif); free(kif, PFI_MTYPE, 0); } int pfi_kif_match(struct pfi_kif *rule_kif, struct pfi_kif *packet_kif) { struct ifg_list *p; if (rule_kif == NULL || rule_kif == packet_kif) return (1); if (rule_kif->pfik_group != NULL) TAILQ_FOREACH(p, &packet_kif->pfik_ifp->if_groups, ifgl_next) if (p->ifgl_group == rule_kif->pfik_group) return (1); if (rule_kif->pfik_flags & PFI_IFLAG_ANY && packet_kif->pfik_ifp && !(packet_kif->pfik_ifp->if_flags & IFF_LOOPBACK)) return (1); return (0); } void pfi_attach_ifnet(struct ifnet *ifp) { struct pfi_kif *kif; int s; pfi_initialize(); s = splsoftnet(); pfi_update++; if ((kif = pfi_kif_get(ifp->if_xname)) == NULL) panic("pfi_kif_get failed"); kif->pfik_ifp = ifp; ifp->if_pf_kif = (caddr_t)kif; if ((kif->pfik_ah_cookie = hook_establish(ifp->if_addrhooks, 1, pfi_kifaddr_update, kif)) == NULL) panic("pfi_attach_ifnet: cannot allocate '%s' address hook", ifp->if_xname); pfi_kif_update(kif); splx(s); } void pfi_detach_ifnet(struct ifnet *ifp) { int s; struct pfi_kif *kif; if ((kif = (struct pfi_kif *)ifp->if_pf_kif) == NULL) return; s = splsoftnet(); pfi_update++; hook_disestablish(ifp->if_addrhooks, kif->pfik_ah_cookie); pfi_kif_update(kif); kif->pfik_ifp = NULL; ifp->if_pf_kif = NULL; pfi_kif_unref(kif, PFI_KIF_REF_NONE); splx(s); } void pfi_attach_ifgroup(struct ifg_group *ifg) { struct pfi_kif *kif; int s; pfi_initialize(); s = splsoftnet(); pfi_update++; if ((kif = pfi_kif_get(ifg->ifg_group)) == NULL) panic("pfi_kif_get failed"); kif->pfik_group = ifg; ifg->ifg_pf_kif = (caddr_t)kif; splx(s); } void pfi_detach_ifgroup(struct ifg_group *ifg) { int s; struct pfi_kif *kif; if ((kif = (struct pfi_kif *)ifg->ifg_pf_kif) == NULL) return; s = splsoftnet(); pfi_update++; kif->pfik_group = NULL; ifg->ifg_pf_kif = NULL; pfi_kif_unref(kif, PFI_KIF_REF_NONE); splx(s); } void pfi_group_change(const char *group) { struct pfi_kif *kif; int s; s = splsoftnet(); pfi_update++; if ((kif = pfi_kif_get(group)) == NULL) panic("pfi_kif_get failed"); pfi_kif_update(kif); splx(s); } int pfi_match_addr(struct pfi_dynaddr *dyn, struct pf_addr *a, sa_family_t af) { switch (af) { case AF_INET: switch (dyn->pfid_acnt4) { case 0: return (0); case 1: return (PF_MATCHA(0, &dyn->pfid_addr4, &dyn->pfid_mask4, a, AF_INET)); default: return (pfr_match_addr(dyn->pfid_kt, a, AF_INET)); } break; #ifdef INET6 case AF_INET6: switch (dyn->pfid_acnt6) { case 0: return (0); case 1: return (PF_MATCHA(0, &dyn->pfid_addr6, &dyn->pfid_mask6, a, AF_INET6)); default: return (pfr_match_addr(dyn->pfid_kt, a, AF_INET6)); } break; #endif /* INET6 */ default: return (0); } } int pfi_dynaddr_setup(struct pf_addr_wrap *aw, sa_family_t af) { struct pfi_dynaddr *dyn; char tblname[PF_TABLE_NAME_SIZE]; struct pf_ruleset *ruleset = NULL; int s, rv = 0; if (aw->type != PF_ADDR_DYNIFTL) return (0); if ((dyn = pool_get(&pfi_addr_pl, PR_WAITOK | PR_LIMITFAIL | PR_ZERO)) == NULL) return (1); s = splsoftnet(); if (!strcmp(aw->v.ifname, "self")) dyn->pfid_kif = pfi_kif_get(IFG_ALL); else dyn->pfid_kif = pfi_kif_get(aw->v.ifname); if (dyn->pfid_kif == NULL) { rv = 1; goto _bad; } pfi_kif_ref(dyn->pfid_kif, PFI_KIF_REF_RULE); dyn->pfid_net = pfi_unmask(&aw->v.a.mask); if (af == AF_INET && dyn->pfid_net == 32) dyn->pfid_net = 128; strlcpy(tblname, aw->v.ifname, sizeof(tblname)); if (aw->iflags & PFI_AFLAG_NETWORK) strlcat(tblname, ":network", sizeof(tblname)); if (aw->iflags & PFI_AFLAG_BROADCAST) strlcat(tblname, ":broadcast", sizeof(tblname)); if (aw->iflags & PFI_AFLAG_PEER) strlcat(tblname, ":peer", sizeof(tblname)); if (aw->iflags & PFI_AFLAG_NOALIAS) strlcat(tblname, ":0", sizeof(tblname)); if (dyn->pfid_net != 128) snprintf(tblname + strlen(tblname), sizeof(tblname) - strlen(tblname), "/%d", dyn->pfid_net); if ((ruleset = pf_find_or_create_ruleset(PF_RESERVED_ANCHOR)) == NULL) { rv = 1; goto _bad; } if ((dyn->pfid_kt = pfr_attach_table(ruleset, tblname, 1)) == NULL) { rv = 1; goto _bad; } dyn->pfid_kt->pfrkt_flags |= PFR_TFLAG_ACTIVE; dyn->pfid_iflags = aw->iflags; dyn->pfid_af = af; TAILQ_INSERT_TAIL(&dyn->pfid_kif->pfik_dynaddrs, dyn, entry); aw->p.dyn = dyn; pfi_kif_update(dyn->pfid_kif); splx(s); return (0); _bad: if (dyn->pfid_kt != NULL) pfr_detach_table(dyn->pfid_kt); if (ruleset != NULL) pf_remove_if_empty_ruleset(ruleset); if (dyn->pfid_kif != NULL) pfi_kif_unref(dyn->pfid_kif, PFI_KIF_REF_RULE); pool_put(&pfi_addr_pl, dyn); splx(s); return (rv); } void pfi_kif_update(struct pfi_kif *kif) { struct ifg_list *ifgl; struct pfi_dynaddr *p; /* update all dynaddr */ TAILQ_FOREACH(p, &kif->pfik_dynaddrs, entry) pfi_dynaddr_update(p); /* again for all groups kif is member of */ if (kif->pfik_ifp != NULL) TAILQ_FOREACH(ifgl, &kif->pfik_ifp->if_groups, ifgl_next) pfi_kif_update((struct pfi_kif *) ifgl->ifgl_group->ifg_pf_kif); } void pfi_dynaddr_update(struct pfi_dynaddr *dyn) { struct pfi_kif *kif; struct pfr_ktable *kt; if (dyn == NULL || dyn->pfid_kif == NULL || dyn->pfid_kt == NULL) panic("pfi_dynaddr_update"); kif = dyn->pfid_kif; kt = dyn->pfid_kt; if (kt->pfrkt_larg != pfi_update) { /* this table needs to be brought up-to-date */ pfi_table_update(kt, kif, dyn->pfid_net, dyn->pfid_iflags); kt->pfrkt_larg = pfi_update; } pfr_dynaddr_update(kt, dyn); } void pfi_table_update(struct pfr_ktable *kt, struct pfi_kif *kif, u_int8_t net, int flags) { int e, size2 = 0; struct ifg_member *ifgm; pfi_buffer_cnt = 0; if (kif->pfik_ifp != NULL) pfi_instance_add(kif->pfik_ifp, net, flags); else if (kif->pfik_group != NULL) TAILQ_FOREACH(ifgm, &kif->pfik_group->ifg_members, ifgm_next) pfi_instance_add(ifgm->ifgm_ifp, net, flags); if ((e = pfr_set_addrs(&kt->pfrkt_t, pfi_buffer, pfi_buffer_cnt, &size2, NULL, NULL, NULL, 0, PFR_TFLAG_ALLMASK))) DPFPRINTF(LOG_ERR, "pfi_table_update: cannot set %d new addresses " "into table %s: %d", pfi_buffer_cnt, kt->pfrkt_name, e); } void pfi_instance_add(struct ifnet *ifp, u_int8_t net, int flags) { struct ifaddr *ifa; int got4 = 0, got6 = 0; int net2, af; if (ifp == NULL) return; TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) { if (ifa->ifa_addr == NULL) continue; af = ifa->ifa_addr->sa_family; if (af != AF_INET && af != AF_INET6) continue; if ((flags & PFI_AFLAG_BROADCAST) && af == AF_INET6) continue; if ((flags & PFI_AFLAG_BROADCAST) && !(ifp->if_flags & IFF_BROADCAST)) continue; if ((flags & PFI_AFLAG_PEER) && !(ifp->if_flags & IFF_POINTOPOINT)) continue; if ((flags & PFI_AFLAG_NETWORK) && af == AF_INET6 && IN6_IS_ADDR_LINKLOCAL( &((struct sockaddr_in6 *)ifa->ifa_addr)->sin6_addr)) continue; if (flags & PFI_AFLAG_NOALIAS) { if (af == AF_INET && got4) continue; if (af == AF_INET6 && got6) continue; } if (af == AF_INET) got4 = 1; else if (af == AF_INET6) got6 = 1; net2 = net; if (net2 == 128 && (flags & PFI_AFLAG_NETWORK)) { if (af == AF_INET) net2 = pfi_unmask(&((struct sockaddr_in *) ifa->ifa_netmask)->sin_addr); else if (af == AF_INET6) net2 = pfi_unmask(&((struct sockaddr_in6 *) ifa->ifa_netmask)->sin6_addr); } if (af == AF_INET && net2 > 32) net2 = 32; if (flags & PFI_AFLAG_BROADCAST) pfi_address_add(ifa->ifa_broadaddr, af, net2); else if (flags & PFI_AFLAG_PEER) pfi_address_add(ifa->ifa_dstaddr, af, net2); else pfi_address_add(ifa->ifa_addr, af, net2); } } void pfi_address_add(struct sockaddr *sa, sa_family_t af, u_int8_t net) { struct pfr_addr *p; int i; if (pfi_buffer_cnt >= pfi_buffer_max) { int new_max = pfi_buffer_max * 2; if (new_max > PFI_BUFFER_MAX) { DPFPRINTF(LOG_ERR, "pfi_address_add: address buffer full (%d/%d)", pfi_buffer_cnt, PFI_BUFFER_MAX); return; } p = mallocarray(new_max, sizeof(*pfi_buffer), PFI_MTYPE, M_DONTWAIT); if (p == NULL) { DPFPRINTF(LOG_ERR, "pfi_address_add: no memory to grow buffer " "(%d/%d)", pfi_buffer_cnt, PFI_BUFFER_MAX); return; } memcpy(p, pfi_buffer, pfi_buffer_max * sizeof(*pfi_buffer)); /* no need to zero buffer */ free(pfi_buffer, PFI_MTYPE, 0); pfi_buffer = p; pfi_buffer_max = new_max; } if (af == AF_INET && net > 32) net = 128; p = pfi_buffer + pfi_buffer_cnt++; bzero(p, sizeof(*p)); p->pfra_af = af; p->pfra_net = net; if (af == AF_INET) p->pfra_ip4addr = ((struct sockaddr_in *)sa)->sin_addr; else if (af == AF_INET6) { p->pfra_ip6addr = ((struct sockaddr_in6 *)sa)->sin6_addr; if (IN6_IS_SCOPE_EMBED(&p->pfra_ip6addr)) p->pfra_ip6addr.s6_addr16[1] = 0; } /* mask network address bits */ if (net < 128) ((caddr_t)p)[p->pfra_net/8] &= ~(0xFF >> (p->pfra_net%8)); for (i = (p->pfra_net+7)/8; i < sizeof(p->pfra_u); i++) ((caddr_t)p)[i] = 0; } void pfi_dynaddr_remove(struct pf_addr_wrap *aw) { int s; if (aw->type != PF_ADDR_DYNIFTL || aw->p.dyn == NULL || aw->p.dyn->pfid_kif == NULL || aw->p.dyn->pfid_kt == NULL) return; s = splsoftnet(); TAILQ_REMOVE(&aw->p.dyn->pfid_kif->pfik_dynaddrs, aw->p.dyn, entry); pfi_kif_unref(aw->p.dyn->pfid_kif, PFI_KIF_REF_RULE); aw->p.dyn->pfid_kif = NULL; pfr_detach_table(aw->p.dyn->pfid_kt); aw->p.dyn->pfid_kt = NULL; pool_put(&pfi_addr_pl, aw->p.dyn); aw->p.dyn = NULL; splx(s); } void pfi_dynaddr_copyout(struct pf_addr_wrap *aw) { if (aw->type != PF_ADDR_DYNIFTL || aw->p.dyn == NULL || aw->p.dyn->pfid_kif == NULL) return; aw->p.dyncnt = aw->p.dyn->pfid_acnt4 + aw->p.dyn->pfid_acnt6; } void pfi_kifaddr_update(void *v) { int s; struct pfi_kif *kif = (struct pfi_kif *)v; s = splsoftnet(); pfi_update++; pfi_kif_update(kif); splx(s); } int pfi_if_compare(struct pfi_kif *p, struct pfi_kif *q) { return (strncmp(p->pfik_name, q->pfik_name, IFNAMSIZ)); } void pfi_update_status(const char *name, struct pf_status *pfs) { struct pfi_kif *p; struct pfi_kif_cmp key; struct ifg_member p_member, *ifgm; TAILQ_HEAD(, ifg_member) ifg_members; int i, j, k, s; s = splsoftnet(); if (*name == '\0' && pfs == NULL) { RB_FOREACH(p, pfi_ifhead, &pfi_ifs) { bzero(p->pfik_packets, sizeof(p->pfik_packets)); bzero(p->pfik_bytes, sizeof(p->pfik_bytes)); p->pfik_tzero = time_second; } splx(s); return; } strlcpy(key.pfik_name, name, sizeof(key.pfik_name)); p = RB_FIND(pfi_ifhead, &pfi_ifs, (struct pfi_kif *)&key); if (p == NULL) { splx(s); return; } if (p->pfik_group != NULL) { memcpy(&ifg_members, &p->pfik_group->ifg_members, sizeof(ifg_members)); } else { /* build a temporary list for p only */ bzero(&p_member, sizeof(p_member)); p_member.ifgm_ifp = p->pfik_ifp; TAILQ_INIT(&ifg_members); TAILQ_INSERT_TAIL(&ifg_members, &p_member, ifgm_next); } if (pfs) { bzero(pfs->pcounters, sizeof(pfs->pcounters)); bzero(pfs->bcounters, sizeof(pfs->bcounters)); } TAILQ_FOREACH(ifgm, &ifg_members, ifgm_next) { if (ifgm->ifgm_ifp == NULL) continue; p = (struct pfi_kif *)ifgm->ifgm_ifp->if_pf_kif; /* just clear statistics */ if (pfs == NULL) { bzero(p->pfik_packets, sizeof(p->pfik_packets)); bzero(p->pfik_bytes, sizeof(p->pfik_bytes)); p->pfik_tzero = time_second; continue; } for (i = 0; i < 2; i++) for (j = 0; j < 2; j++) for (k = 0; k < 2; k++) { pfs->pcounters[i][j][k] += p->pfik_packets[i][j][k]; pfs->bcounters[i][j] += p->pfik_bytes[i][j][k]; } } splx(s); } int pfi_get_ifaces(const char *name, struct pfi_kif *buf, int *size) { struct pfi_kif *p, *nextp; int s, n = 0; s = splsoftnet(); for (p = RB_MIN(pfi_ifhead, &pfi_ifs); p; p = nextp) { nextp = RB_NEXT(pfi_ifhead, &pfi_ifs, p); if (pfi_skip_if(name, p)) continue; if (*size > n++) { if (!p->pfik_tzero) p->pfik_tzero = time_second; pfi_kif_ref(p, PFI_KIF_REF_RULE); if (copyout(p, buf++, sizeof(*buf))) { pfi_kif_unref(p, PFI_KIF_REF_RULE); splx(s); return (EFAULT); } nextp = RB_NEXT(pfi_ifhead, &pfi_ifs, p); pfi_kif_unref(p, PFI_KIF_REF_RULE); } } splx(s); *size = n; return (0); } int pfi_skip_if(const char *filter, struct pfi_kif *p) { struct ifg_list *i; int n; if (filter == NULL || !*filter) return (0); if (!strcmp(p->pfik_name, filter)) return (0); /* exact match */ n = strlen(filter); if (n < 1 || n >= IFNAMSIZ) return (1); /* sanity check */ if (filter[n-1] >= '0' && filter[n-1] <= '9') return (1); /* group names may not end in a digit */ if (p->pfik_ifp != NULL) TAILQ_FOREACH(i, &p->pfik_ifp->if_groups, ifgl_next) if (!strncmp(i->ifgl_group->ifg_group, filter, IFNAMSIZ)) return (0); /* iface is in group "filter" */ return (1); } int pfi_set_flags(const char *name, int flags) { struct pfi_kif *p; int s; s = splsoftnet(); RB_FOREACH(p, pfi_ifhead, &pfi_ifs) { if (pfi_skip_if(name, p)) continue; p->pfik_flags_new = p->pfik_flags | flags; } splx(s); return (0); } int pfi_clear_flags(const char *name, int flags) { struct pfi_kif *p; int s; s = splsoftnet(); RB_FOREACH(p, pfi_ifhead, &pfi_ifs) { if (pfi_skip_if(name, p)) continue; p->pfik_flags_new = p->pfik_flags & ~flags; } splx(s); return (0); } void pfi_xcommit(void) { struct pfi_kif *p; int s; s = splsoftnet(); RB_FOREACH(p, pfi_ifhead, &pfi_ifs) p->pfik_flags = p->pfik_flags_new; splx(s); } /* from pf_print_state.c */ int pfi_unmask(void *addr) { struct pf_addr *m = addr; int i = 31, j = 0, b = 0; u_int32_t tmp; while (j < 4 && m->addr32[j] == 0xffffffff) { b += 32; j++; } if (j < 4) { tmp = ntohl(m->addr32[j]); for (i = 31; tmp & (1 << i); --i) b++; } return (b); }