| /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
| |
| /*** |
| This file is part of systemd. |
| |
| Copyright 2008-2011 Lennart Poettering |
| |
| systemd is free software; you can redistribute it and/or modify it |
| under the terms of the GNU Lesser General Public License as published by |
| the Free Software Foundation; either version 2.1 of the License, or |
| (at your option) any later version. |
| |
| systemd 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 |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public License |
| along with systemd; If not, see <http://www.gnu.org/licenses/>. |
| ***/ |
| |
| #include <limits.h> |
| #include <nss.h> |
| #include <sys/types.h> |
| #include <netdb.h> |
| #include <errno.h> |
| #include <string.h> |
| #include <unistd.h> |
| #include <net/if.h> |
| #include <stdlib.h> |
| #include <arpa/inet.h> |
| |
| #include "ifconf.h" |
| #include "macro.h" |
| |
| /* Ensure that glibc's assert is used. We cannot use assert from macro.h, as |
| * libnss_myhostname will be linked into arbitrary programs which will, in turn |
| * attempt to write to the journal via log_dispatch() */ |
| #include <assert.h> |
| |
| /* We use 127.0.0.2 as IPv4 address. This has the advantage over |
| * 127.0.0.1 that it can be translated back to the local hostname. For |
| * IPv6 we use ::1 which unfortunately will not translate back to the |
| * hostname but instead something like "localhost6" or so. */ |
| |
| #define LOCALADDRESS_IPV4 (htonl(0x7F000002)) |
| #define LOCALADDRESS_IPV6 &in6addr_loopback |
| #define LOOPBACK_INTERFACE "lo" |
| |
| enum nss_status _nss_myhostname_gethostbyname4_r( |
| const char *name, |
| struct gaih_addrtuple **pat, |
| char *buffer, size_t buflen, |
| int *errnop, int *h_errnop, |
| int32_t *ttlp) _public_; |
| |
| enum nss_status _nss_myhostname_gethostbyname3_r( |
| const char *name, |
| int af, |
| struct hostent *host, |
| char *buffer, size_t buflen, |
| int *errnop, int *h_errnop, |
| int32_t *ttlp, |
| char **canonp) _public_; |
| |
| enum nss_status _nss_myhostname_gethostbyname2_r( |
| const char *name, |
| int af, |
| struct hostent *host, |
| char *buffer, size_t buflen, |
| int *errnop, int *h_errnop) _public_; |
| |
| enum nss_status _nss_myhostname_gethostbyname_r( |
| const char *name, |
| struct hostent *host, |
| char *buffer, size_t buflen, |
| int *errnop, int *h_errnop) _public_; |
| |
| enum nss_status _nss_myhostname_gethostbyaddr2_r( |
| const void* addr, socklen_t len, |
| int af, |
| struct hostent *host, |
| char *buffer, size_t buflen, |
| int *errnop, int *h_errnop, |
| int32_t *ttlp) _public_; |
| |
| enum nss_status _nss_myhostname_gethostbyaddr_r( |
| const void* addr, socklen_t len, |
| int af, |
| struct hostent *host, |
| char *buffer, size_t buflen, |
| int *errnop, int *h_errnop) _public_; |
| |
| enum nss_status _nss_myhostname_gethostbyname4_r( |
| const char *name, |
| struct gaih_addrtuple **pat, |
| char *buffer, size_t buflen, |
| int *errnop, int *h_errnop, |
| int32_t *ttlp) { |
| |
| unsigned lo_ifi; |
| char hn[HOST_NAME_MAX+1] = {}; |
| const char *canonical = NULL; |
| size_t l, idx, ms; |
| char *r_name; |
| struct gaih_addrtuple *r_tuple, *r_tuple_prev = NULL; |
| struct address *addresses = NULL, *a; |
| unsigned n_addresses = 0, n; |
| uint32_t local_address_ipv4; |
| |
| if (strcasecmp(name, "localhost") == 0) { |
| /* We respond to 'localhost', so that /etc/hosts |
| * is optional */ |
| |
| canonical = "localhost"; |
| local_address_ipv4 = htonl(INADDR_LOOPBACK); |
| } else { |
| /* We respond to our local host name */ |
| |
| if (gethostname(hn, sizeof(hn)-1) < 0) { |
| *errnop = errno; |
| *h_errnop = NO_RECOVERY; |
| return NSS_STATUS_UNAVAIL; |
| } |
| |
| if (strcasecmp(name, hn) != 0) { |
| *errnop = ENOENT; |
| *h_errnop = HOST_NOT_FOUND; |
| return NSS_STATUS_NOTFOUND; |
| } |
| |
| /* If this fails, n_addresses is 0. Which is fine */ |
| ifconf_acquire_addresses(&addresses, &n_addresses); |
| |
| canonical = hn; |
| local_address_ipv4 = LOCALADDRESS_IPV4; |
| } |
| |
| /* If this call fails we fill in 0 as scope. Which is fine */ |
| lo_ifi = n_addresses <= 0 ? if_nametoindex(LOOPBACK_INTERFACE) : 0; |
| |
| l = strlen(canonical); |
| ms = ALIGN(l+1)+ALIGN(sizeof(struct gaih_addrtuple))*(n_addresses > 0 ? n_addresses : 2); |
| if (buflen < ms) { |
| *errnop = ENOMEM; |
| *h_errnop = NO_RECOVERY; |
| free(addresses); |
| return NSS_STATUS_TRYAGAIN; |
| } |
| |
| /* First, fill in hostname */ |
| r_name = buffer; |
| memcpy(r_name, canonical, l+1); |
| idx = ALIGN(l+1); |
| |
| if (n_addresses <= 0) { |
| /* Second, fill in IPv6 tuple */ |
| r_tuple = (struct gaih_addrtuple*) (buffer + idx); |
| r_tuple->next = r_tuple_prev; |
| r_tuple->name = r_name; |
| r_tuple->family = AF_INET6; |
| memcpy(r_tuple->addr, LOCALADDRESS_IPV6, 16); |
| r_tuple->scopeid = (uint32_t) lo_ifi; |
| |
| idx += ALIGN(sizeof(struct gaih_addrtuple)); |
| r_tuple_prev = r_tuple; |
| |
| /* Third, fill in IPv4 tuple */ |
| r_tuple = (struct gaih_addrtuple*) (buffer + idx); |
| r_tuple->next = r_tuple_prev; |
| r_tuple->name = r_name; |
| r_tuple->family = AF_INET; |
| *(uint32_t*) r_tuple->addr = local_address_ipv4; |
| r_tuple->scopeid = (uint32_t) lo_ifi; |
| |
| idx += ALIGN(sizeof(struct gaih_addrtuple)); |
| r_tuple_prev = r_tuple; |
| } |
| |
| /* Fourth, fill actual addresses in, but in backwards order */ |
| for (a = addresses + n_addresses - 1, n = 0; n < n_addresses; n++, a--) { |
| r_tuple = (struct gaih_addrtuple*) (buffer + idx); |
| r_tuple->next = r_tuple_prev; |
| r_tuple->name = r_name; |
| r_tuple->family = a->family; |
| r_tuple->scopeid = a->ifindex; |
| memcpy(r_tuple->addr, a->address, 16); |
| |
| idx += ALIGN(sizeof(struct gaih_addrtuple)); |
| r_tuple_prev = r_tuple; |
| } |
| |
| /* Verify the size matches */ |
| assert(idx == ms); |
| |
| /* Nscd expects us to store the first record in **pat. */ |
| if (*pat) |
| **pat = *r_tuple_prev; |
| else |
| *pat = r_tuple_prev; |
| |
| if (ttlp) |
| *ttlp = 0; |
| |
| free(addresses); |
| |
| return NSS_STATUS_SUCCESS; |
| } |
| |
| static enum nss_status fill_in_hostent( |
| const char *canonical, const char *additional, |
| int af, |
| struct address *addresses, unsigned n_addresses, |
| uint32_t local_address_ipv4, |
| struct hostent *result, |
| char *buffer, size_t buflen, |
| int *errnop, int *h_errnop, |
| int32_t *ttlp, |
| char **canonp) { |
| |
| size_t l_canonical, l_additional, idx, ms; |
| char *r_addr, *r_name, *r_aliases, *r_alias = NULL, *r_addr_list; |
| size_t alen; |
| struct address *a; |
| unsigned n, c; |
| |
| alen = PROTO_ADDRESS_SIZE(af); |
| |
| for (a = addresses, n = 0, c = 0; n < n_addresses; a++, n++) |
| if (af == a->family) |
| c++; |
| |
| l_canonical = strlen(canonical); |
| l_additional = additional ? strlen(additional) : 0; |
| ms = ALIGN(l_canonical+1)+ |
| (additional ? ALIGN(l_additional+1) : 0) + |
| sizeof(char*)+ |
| (additional ? sizeof(char*) : 0) + |
| (c > 0 ? c : 1)*ALIGN(alen)+ |
| (c > 0 ? c+1 : 2)*sizeof(char*); |
| |
| if (buflen < ms) { |
| *errnop = ENOMEM; |
| *h_errnop = NO_RECOVERY; |
| free(addresses); |
| return NSS_STATUS_TRYAGAIN; |
| } |
| |
| /* First, fill in hostnames */ |
| r_name = buffer; |
| memcpy(r_name, canonical, l_canonical+1); |
| idx = ALIGN(l_canonical+1); |
| |
| if (additional) { |
| r_alias = buffer + idx; |
| memcpy(r_alias, additional, l_additional+1); |
| idx += ALIGN(l_additional+1); |
| } |
| |
| /* Second, create aliases array */ |
| r_aliases = buffer + idx; |
| if (additional) { |
| ((char**) r_aliases)[0] = r_alias; |
| ((char**) r_aliases)[1] = NULL; |
| idx += 2*sizeof(char*); |
| } else { |
| ((char**) r_aliases)[0] = NULL; |
| idx += sizeof(char*); |
| } |
| |
| /* Third, add addresses */ |
| r_addr = buffer + idx; |
| if (c > 0) { |
| unsigned i = 0; |
| |
| for (a = addresses, n = 0; n < n_addresses; a++, n++) { |
| if (af != a->family) |
| continue; |
| |
| memcpy(r_addr + i*ALIGN(alen), a->address, alen); |
| i++; |
| } |
| |
| assert(i == c); |
| idx += c*ALIGN(alen); |
| } else { |
| if (af == AF_INET) |
| *(uint32_t*) r_addr = local_address_ipv4; |
| else |
| memcpy(r_addr, LOCALADDRESS_IPV6, 16); |
| |
| idx += ALIGN(alen); |
| } |
| |
| /* Fourth, add address pointer array */ |
| r_addr_list = buffer + idx; |
| if (c > 0) { |
| unsigned i = 0; |
| |
| for (a = addresses, n = 0; n < n_addresses; a++, n++) { |
| if (af != a->family) |
| continue; |
| |
| ((char**) r_addr_list)[i] = (r_addr + i*ALIGN(alen)); |
| i++; |
| } |
| |
| assert(i == c); |
| ((char**) r_addr_list)[c] = NULL; |
| idx += (c+1)*sizeof(char*); |
| |
| } else { |
| ((char**) r_addr_list)[0] = r_addr; |
| ((char**) r_addr_list)[1] = NULL; |
| idx += 2*sizeof(char*); |
| } |
| |
| /* Verify the size matches */ |
| assert(idx == ms); |
| |
| result->h_name = r_name; |
| result->h_aliases = (char**) r_aliases; |
| result->h_addrtype = af; |
| result->h_length = alen; |
| result->h_addr_list = (char**) r_addr_list; |
| |
| if (ttlp) |
| *ttlp = 0; |
| |
| if (canonp) |
| *canonp = r_name; |
| |
| free(addresses); |
| |
| return NSS_STATUS_SUCCESS; |
| } |
| |
| enum nss_status _nss_myhostname_gethostbyname3_r( |
| const char *name, |
| int af, |
| struct hostent *host, |
| char *buffer, size_t buflen, |
| int *errnop, int *h_errnop, |
| int32_t *ttlp, |
| char **canonp) { |
| |
| char hn[HOST_NAME_MAX+1] = {}; |
| struct address *addresses = NULL; |
| unsigned n_addresses = 0; |
| const char *canonical, *additional = NULL; |
| uint32_t local_address_ipv4; |
| |
| if (af == AF_UNSPEC) |
| af = AF_INET; |
| |
| if (af != AF_INET && af != AF_INET6) { |
| *errnop = EAFNOSUPPORT; |
| *h_errnop = NO_DATA; |
| return NSS_STATUS_UNAVAIL; |
| } |
| |
| if (strcasecmp(name, "localhost") == 0) { |
| canonical = "localhost"; |
| local_address_ipv4 = htonl(INADDR_LOOPBACK); |
| } else { |
| if (gethostname(hn, sizeof(hn)-1) < 0) { |
| *errnop = errno; |
| *h_errnop = NO_RECOVERY; |
| return NSS_STATUS_UNAVAIL; |
| } |
| |
| if (strcasecmp(name, hn) != 0) { |
| *errnop = ENOENT; |
| *h_errnop = HOST_NOT_FOUND; |
| return NSS_STATUS_NOTFOUND; |
| } |
| |
| ifconf_acquire_addresses(&addresses, &n_addresses); |
| |
| canonical = hn; |
| additional = n_addresses <= 0 && af == AF_INET6 ? "localhost" : NULL; |
| local_address_ipv4 = LOCALADDRESS_IPV4; |
| } |
| |
| return fill_in_hostent( |
| canonical, additional, |
| af, |
| addresses, n_addresses, |
| local_address_ipv4, |
| host, |
| buffer, buflen, |
| errnop, h_errnop, |
| ttlp, |
| canonp); |
| } |
| |
| enum nss_status _nss_myhostname_gethostbyname2_r( |
| const char *name, |
| int af, |
| struct hostent *host, |
| char *buffer, size_t buflen, |
| int *errnop, int *h_errnop) { |
| |
| return _nss_myhostname_gethostbyname3_r( |
| name, |
| af, |
| host, |
| buffer, buflen, |
| errnop, h_errnop, |
| NULL, |
| NULL); |
| } |
| |
| enum nss_status _nss_myhostname_gethostbyname_r( |
| const char *name, |
| struct hostent *host, |
| char *buffer, size_t buflen, |
| int *errnop, int *h_errnop) { |
| |
| return _nss_myhostname_gethostbyname3_r( |
| name, |
| AF_UNSPEC, |
| host, |
| buffer, buflen, |
| errnop, h_errnop, |
| NULL, |
| NULL); |
| } |
| |
| enum nss_status _nss_myhostname_gethostbyaddr2_r( |
| const void* addr, socklen_t len, |
| int af, |
| struct hostent *host, |
| char *buffer, size_t buflen, |
| int *errnop, int *h_errnop, |
| int32_t *ttlp) { |
| |
| char hn[HOST_NAME_MAX+1] = {}; |
| struct address *addresses = NULL; |
| struct address *a; |
| unsigned n_addresses = 0, n; |
| uint32_t local_address_ipv4 = LOCALADDRESS_IPV4; |
| const char *canonical = NULL, *additional = NULL; |
| |
| if (len != PROTO_ADDRESS_SIZE(af)) { |
| *errnop = EINVAL; |
| *h_errnop = NO_RECOVERY; |
| return NSS_STATUS_UNAVAIL; |
| } |
| |
| if (af == AF_INET) { |
| |
| if ((*(uint32_t*) addr) == LOCALADDRESS_IPV4) |
| goto found; |
| |
| if ((*(uint32_t*) addr) == htonl(INADDR_LOOPBACK)) { |
| canonical = "localhost"; |
| local_address_ipv4 = htonl(INADDR_LOOPBACK); |
| goto found; |
| } |
| |
| } else if (af == AF_INET6) { |
| |
| if (memcmp(addr, LOCALADDRESS_IPV6, 16) == 0) { |
| additional = "localhost"; |
| goto found; |
| } |
| |
| } else { |
| *errnop = EAFNOSUPPORT; |
| *h_errnop = NO_DATA; |
| return NSS_STATUS_UNAVAIL; |
| } |
| |
| ifconf_acquire_addresses(&addresses, &n_addresses); |
| |
| for (a = addresses, n = 0; n < n_addresses; n++, a++) { |
| if (af != a->family) |
| continue; |
| |
| if (memcmp(addr, a->address, PROTO_ADDRESS_SIZE(af)) == 0) |
| goto found; |
| } |
| |
| *errnop = ENOENT; |
| *h_errnop = HOST_NOT_FOUND; |
| |
| free(addresses); |
| |
| return NSS_STATUS_NOTFOUND; |
| |
| found: |
| if (!canonical) { |
| if (gethostname(hn, sizeof(hn)-1) < 0) { |
| *errnop = errno; |
| *h_errnop = NO_RECOVERY; |
| |
| free(addresses); |
| |
| return NSS_STATUS_UNAVAIL; |
| } |
| |
| canonical = hn; |
| } |
| |
| return fill_in_hostent( |
| canonical, additional, |
| af, |
| addresses, n_addresses, |
| local_address_ipv4, |
| host, |
| buffer, buflen, |
| errnop, h_errnop, |
| ttlp, |
| NULL); |
| |
| } |
| |
| enum nss_status _nss_myhostname_gethostbyaddr_r( |
| const void* addr, socklen_t len, |
| int af, |
| struct hostent *host, |
| char *buffer, size_t buflen, |
| int *errnop, int *h_errnop) { |
| |
| return _nss_myhostname_gethostbyaddr2_r( |
| addr, len, |
| af, |
| host, |
| buffer, buflen, |
| errnop, h_errnop, |
| NULL); |
| } |