From: Lennart Poettering Date: Wed, 16 Jul 2014 01:31:30 +0000 (+0200) Subject: resolved: add small NSS module that uses resolved to resolve DNS names X-Git-Tag: v216~608 X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=commitdiff_plain;h=4d1cf1e229c9bdbc44778c0863eaad918f5724e7;ds=sidebyside resolved: add small NSS module that uses resolved to resolve DNS names --- diff --git a/Makefile.am b/Makefile.am index ee7066ec2..34289fbfc 100644 --- a/Makefile.am +++ b/Makefile.am @@ -4605,6 +4605,26 @@ test_dns_domain_LDADD = \ libsystemd-internal.la \ libsystemd-shared.la +libnss_resolve_la_SOURCES = \ + src/nss-resolve/nss-resolve.sym \ + src/nss-resolve/nss-resolve.c + +libnss_resolve_la_LDFLAGS = \ + $(AM_LDFLAGS) \ + -module \ + -export-dynamic \ + -avoid-version \ + -shared \ + -shrext .so.2 \ + -Wl,--version-script=$(top_srcdir)/src/nss-resolve/nss-resolve.sym + +libnss_resolve_la_LIBADD = \ + libsystemd-shared.la \ + libsystemd-internal.la + +lib_LTLIBRARIES += \ + libnss_resolve.la + endif # ------------------------------------------------------------------------------ diff --git a/src/nss-resolve/Makefile b/src/nss-resolve/Makefile new file mode 120000 index 000000000..d0b0e8e00 --- /dev/null +++ b/src/nss-resolve/Makefile @@ -0,0 +1 @@ +../Makefile \ No newline at end of file diff --git a/src/nss-resolve/nss-resolve.c b/src/nss-resolve/nss-resolve.c new file mode 100644 index 000000000..7b0c24fbe --- /dev/null +++ b/src/nss-resolve/nss-resolve.c @@ -0,0 +1,585 @@ +/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ + +/*** + This file is part of systemd. + + Copyright 2014 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 . +***/ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "sd-bus.h" +#include "bus-util.h" +#include "bus-errors.h" +#include "macro.h" +#include "nss-util.h" +#include "util.h" +#include "in-addr-util.h" + +NSS_GETHOSTBYNAME_PROTOTYPES(resolve); +NSS_GETHOSTBYADDR_PROTOTYPES(resolve); + +#define DNS_CALL_TIMEOUT_USEC (45*USEC_PER_SEC) + +static int count_addresses(sd_bus_message *m, unsigned af, unsigned *ret) { + unsigned c = 0; + int r; + + assert(m); + assert(ret); + + while ((r = sd_bus_message_enter_container(m, 'r', "yayi")) > 0) { + unsigned char family; + + r = sd_bus_message_read(m, "y", &family); + if (r < 0) + return r; + + r = sd_bus_message_skip(m, "ayi"); + if (r < 0) + return r; + + r = sd_bus_message_exit_container(m); + if (r < 0) + return r; + + if (af != AF_UNSPEC && family != af) + continue; + + c ++; + } + if (r < 0) + return r; + + r = sd_bus_message_rewind(m, false); + if (r < 0) + return r; + + *ret = c; + return 0; +} + +enum nss_status _nss_resolve_gethostbyname4_r( + const char *name, + struct gaih_addrtuple **pat, + char *buffer, size_t buflen, + int *errnop, int *h_errnop, + int32_t *ttlp) { + + _cleanup_bus_message_unref_ sd_bus_message *req = NULL, *reply = NULL; + _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL; + struct gaih_addrtuple *r_tuple, *r_tuple_first = NULL; + _cleanup_bus_unref_ sd_bus *bus = NULL; + size_t l, ms, idx; + char *r_name; + unsigned i = 0, c = 0; + int r; + + assert(name); + assert(pat); + assert(buffer); + assert(errnop); + assert(h_errnop); + + r = sd_bus_open_system(&bus); + if (r < 0) + goto fail; + + r = sd_bus_message_new_method_call( + bus, + &req, + "org.freedesktop.resolve1", + "/org/freedesktop/resolve1", + "org.freedesktop.resolve1.Manager", + "ResolveHostname"); + if (r < 0) + goto fail; + + r = sd_bus_message_set_auto_start(req, false); + if (r < 0) + goto fail; + + r = sd_bus_message_append(req, "sy", name, AF_UNSPEC); + if (r < 0) + goto fail; + + r = sd_bus_call(bus, req, DNS_CALL_TIMEOUT_USEC, &error, &reply); + if (r < 0) { + if (sd_bus_error_has_name(&error, _BUS_ERROR_DNS "NXDOMAIN")) { + *errnop = ESRCH; + *h_errnop = HOST_NOT_FOUND; + return NSS_STATUS_NOTFOUND; + } + + *errnop = -r; + *h_errnop = NO_RECOVERY; + return NSS_STATUS_UNAVAIL; + } + + r = sd_bus_message_enter_container(reply, 'a', "(yayi)"); + if (r < 0) + goto fail; + + r = count_addresses(reply, AF_UNSPEC, &c); + if (r < 0) + goto fail; + + if (c <= 0) { + *errnop = ESRCH; + *h_errnop = HOST_NOT_FOUND; + return NSS_STATUS_NOTFOUND; + } + + l = strlen(name); + ms = ALIGN(l+1) + ALIGN(sizeof(struct gaih_addrtuple)) * c; + if (buflen < ms) { + *errnop = ENOMEM; + *h_errnop = TRY_AGAIN; + return NSS_STATUS_TRYAGAIN; + } + + /* First, append name */ + r_name = buffer; + memcpy(r_name, name, l+1); + idx = ALIGN(l+1); + + /* Second, append addresses */ + r_tuple_first = (struct gaih_addrtuple*) (buffer + idx); + while ((r = sd_bus_message_enter_container(reply, 'r', "yayi")) > 0) { + unsigned char family; + const void *a; + int ifindex; + size_t sz; + + r = sd_bus_message_read(reply, "y", &family); + if (r < 0) + goto fail; + + r = sd_bus_message_read_array(reply, 'y', &a, &sz); + if (r < 0) + goto fail; + + r = sd_bus_message_read(reply, "i", &ifindex); + if (r < 0) + goto fail; + + r = sd_bus_message_exit_container(reply); + if (r < 0) + goto fail; + + if (!IN_SET(family, AF_INET, AF_INET6)) + continue; + + if (sz != PROTO_ADDRESS_SIZE(family)) { + r = -EINVAL; + goto fail; + } + + if (ifindex < 0) { + r = -EINVAL; + goto fail; + } + + r_tuple = (struct gaih_addrtuple*) (buffer + idx); + r_tuple->next = i == c-1 ? NULL : (struct gaih_addrtuple*) ((char*) r_tuple + ALIGN(sizeof(struct gaih_addrtuple))); + r_tuple->name = r_name; + r_tuple->family = family; + r_tuple->scopeid = ifindex; + memcpy(r_tuple->addr, a, sz); + + idx += ALIGN(sizeof(struct gaih_addrtuple)); + i++; + } + + assert(i == c); + + r = sd_bus_message_exit_container(reply); + if (r < 0) + goto fail; + + assert(idx == ms); + + if (*pat) + **pat = *r_tuple_first; + else + *pat = r_tuple_first; + + if (ttlp) + *ttlp = 0; + + return NSS_STATUS_SUCCESS; + +fail: + *errnop = -r; + *h_errnop = NO_DATA; + return NSS_STATUS_UNAVAIL; +} + +enum nss_status _nss_resolve_gethostbyname3_r( + const char *name, + int af, + struct hostent *result, + char *buffer, size_t buflen, + int *errnop, int *h_errnop, + int32_t *ttlp, + char **canonp) { + + _cleanup_bus_message_unref_ sd_bus_message *req = NULL, *reply = NULL; + _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL; + char *r_name, *r_aliases, *r_addr, *r_addr_list; + _cleanup_bus_unref_ sd_bus *bus = NULL; + unsigned c = 0, i = 0; + size_t l, idx, ms, alen; + int r; + + assert(name); + assert(result); + assert(buffer); + assert(errnop); + assert(h_errnop); + + if (af == AF_UNSPEC) + af = AF_INET; + + if (af != AF_INET && af != AF_INET6) { + r = -EAFNOSUPPORT; + goto fail; + } + + r = sd_bus_open_system(&bus); + if (r < 0) + goto fail; + + r = sd_bus_message_new_method_call( + bus, + &req, + "org.freedesktop.resolve1", + "/org/freedesktop/resolve1", + "org.freedesktop.resolve1.Manager", + "ResolveHostname"); + if (r < 0) + goto fail; + + r = sd_bus_message_set_auto_start(req, false); + if (r < 0) + goto fail; + + r = sd_bus_message_append(req, "sy", name, af); + if (r < 0) + goto fail; + + r = sd_bus_call(bus, req, DNS_CALL_TIMEOUT_USEC, &error, &reply); + if (r < 0) { + if (sd_bus_error_has_name(&error, _BUS_ERROR_DNS "NXDOMAIN")) { + *errnop = ESRCH; + *h_errnop = HOST_NOT_FOUND; + return NSS_STATUS_NOTFOUND; + } + + *errnop = -r; + *h_errnop = NO_RECOVERY; + return NSS_STATUS_UNAVAIL; + } + + r = sd_bus_message_enter_container(reply, 'a', "(yayi)"); + if (r < 0) + goto fail; + + r = count_addresses(reply, af, &c); + if (r < 0) + goto fail; + + if (c <= 0) { + *errnop = ESRCH; + *h_errnop = HOST_NOT_FOUND; + return NSS_STATUS_NOTFOUND; + } + + alen = PROTO_ADDRESS_SIZE(af); + l = strlen(name); + + ms = ALIGN(l+1) + + sizeof(char*) + + (c > 0 ? c : 1) * ALIGN(alen) + + (c > 0 ? c+1 : 2) * sizeof(char*); + + if (buflen < ms) { + *errnop = ENOMEM; + *h_errnop = TRY_AGAIN; + return NSS_STATUS_TRYAGAIN; + } + + /* First, append name */ + r_name = buffer; + memcpy(r_name, name, l+1); + idx = ALIGN(l+1); + + /* Second, create aliases array */ + r_aliases = buffer + idx; + ((char**) r_aliases)[0] = NULL; + idx += sizeof(char*); + + /* Third, append addresses */ + r_addr = buffer + idx; + while ((r = sd_bus_message_enter_container(reply, 'r', "yayi")) > 0) { + unsigned char family; + const void *a; + int ifindex; + size_t sz; + + r = sd_bus_message_read(reply, "y", &family); + if (r < 0) + goto fail; + + r = sd_bus_message_read_array(reply, 'y', &a, &sz); + if (r < 0) + goto fail; + + r = sd_bus_message_read(reply, "i", &ifindex); + if (r < 0) + goto fail; + + r = sd_bus_message_exit_container(reply); + if (r < 0) + goto fail; + + if (family != af) + continue; + + if (sz != alen) { + r = -EINVAL; + goto fail; + } + + if (ifindex < 0) { + r = -EINVAL; + goto fail; + } + + memcpy(r_addr + i*ALIGN(alen), a, alen); + i++; + } + + assert(i == c); + idx += c * ALIGN(alen); + + r = sd_bus_message_exit_container(reply); + if (r < 0) + goto fail; + + /* Third, append address pointer array */ + r_addr_list = buffer + idx; + for (i = 0; i < c; i++) + ((char**) r_addr_list)[i] = r_addr + i*ALIGN(alen); + + ((char**) r_addr_list)[i] = NULL; + idx += (c+1) * sizeof(char*); + + 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; + + return NSS_STATUS_SUCCESS; + +fail: + *errnop = -r; + *h_errnop = NO_DATA; + return NSS_STATUS_UNAVAIL; +} + +enum nss_status _nss_resolve_gethostbyaddr2_r( + const void* addr, socklen_t len, + int af, + struct hostent *result, + char *buffer, size_t buflen, + int *errnop, int *h_errnop, + int32_t *ttlp) { + + _cleanup_bus_message_unref_ sd_bus_message *req = NULL, *reply = NULL; + _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL; + char *r_name, *r_aliases, *r_addr, *r_addr_list; + _cleanup_bus_unref_ sd_bus *bus = NULL; + unsigned c = 0, i = 0; + size_t ms = 0, idx; + const char *n; + int r; + + assert(addr); + assert(result); + assert(buffer); + assert(errnop); + assert(h_errnop); + + if (!IN_SET(af, AF_INET, AF_INET6)) { + *errnop = EAFNOSUPPORT; + *h_errnop = NO_DATA; + return NSS_STATUS_UNAVAIL; + } + + if (len != PROTO_ADDRESS_SIZE(af)) { + *errnop = EINVAL; + *h_errnop = NO_RECOVERY; + return NSS_STATUS_UNAVAIL; + } + + r = sd_bus_open_system(&bus); + if (r < 0) + goto fail; + + r = sd_bus_message_new_method_call( + bus, + &req, + "org.freedesktop.resolve1", + "/org/freedesktop/resolve1", + "org.freedesktop.resolve1.Manager", + "ResolveAddress"); + if (r < 0) + goto fail; + + r = sd_bus_message_set_auto_start(req, false); + if (r < 0) + goto fail; + + r = sd_bus_message_append(req, "y", af); + if (r < 0) + goto fail; + + r = sd_bus_message_append_array(req, 'y', addr, len); + if (r < 0) + goto fail; + + r = sd_bus_message_append(req, "i", 0); + if (r < 0) + goto fail; + + r = sd_bus_call(bus, req, DNS_CALL_TIMEOUT_USEC, &error, &reply); + if (r < 0) { + if (sd_bus_error_has_name(&error, _BUS_ERROR_DNS "NXDOMAIN")) { + *errnop = ESRCH; + *h_errnop = HOST_NOT_FOUND; + return NSS_STATUS_NOTFOUND; + } + + *errnop = -r; + *h_errnop = NO_RECOVERY; + return NSS_STATUS_UNAVAIL; + } + + r = sd_bus_message_enter_container(reply, 'a', "s"); + if (r < 0) + goto fail; + + while ((r = sd_bus_message_read(reply, "s", &n)) > 0) { + c++; + ms += ALIGN(strlen(n) + 1); + } + if (r < 0) + goto fail; + + r = sd_bus_message_rewind(reply, false); + if (r < 0) + return r; + + if (c <= 0) { + *errnop = ESRCH; + *h_errnop = HOST_NOT_FOUND; + return NSS_STATUS_NOTFOUND; + } + + ms += ALIGN(len) + /* the address */ + 2 * sizeof(char*) + /* pointers to the address, plus trailing NULL */ + c * sizeof(char*); /* pointers to aliases, plus trailing NULL */ + + if (buflen < ms) { + *errnop = ENOMEM; + *h_errnop = TRY_AGAIN; + return NSS_STATUS_TRYAGAIN; + } + + /* First, place address */ + r_addr = buffer; + memcpy(r_addr, addr, len); + idx = ALIGN(len); + + /* Second, place address list */ + r_addr_list = buffer + idx; + ((char**) r_addr_list)[0] = r_addr; + ((char**) r_addr_list)[1] = NULL; + idx += sizeof(char*) * 2; + + /* Third, reserve space for the aliases array */ + r_aliases = buffer + idx; + idx += sizeof(char*) * c; + + /* Fourth, place aliases */ + i = 0; + r_name = buffer + idx; + while ((r = sd_bus_message_read(reply, "s", &n)) > 0) { + char *p; + size_t l; + + l = strlen(n); + p = buffer + idx; + memcpy(p, n, l+1); + + if (i > 1) + ((char**) r_aliases)[i-1] = p; + i++; + + idx += ALIGN(l+1); + } + + ((char**) r_aliases)[c-1] = NULL; + assert(idx == ms); + + result->h_name = r_name; + result->h_aliases = (char**) r_aliases; + result->h_addrtype = af; + result->h_length = len; + result->h_addr_list = (char**) r_addr_list; + + if (ttlp) + *ttlp = 0; + + return NSS_STATUS_SUCCESS; + +fail: + *errnop = -r; + *h_errnop = NO_DATA; + return NSS_STATUS_UNAVAIL; +} + +NSS_GETHOSTBYNAME_FALLBACKS(resolve); +NSS_GETHOSTBYADDR_FALLBACKS(resolve); diff --git a/src/nss-resolve/nss-resolve.sym b/src/nss-resolve/nss-resolve.sym new file mode 100644 index 000000000..df8dff2a2 --- /dev/null +++ b/src/nss-resolve/nss-resolve.sym @@ -0,0 +1,19 @@ +/*** + This file is part of systemd. + + 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. +***/ + +{ +global: + _nss_resolve_gethostbyname_r; + _nss_resolve_gethostbyname2_r; + _nss_resolve_gethostbyname3_r; + _nss_resolve_gethostbyname4_r; + _nss_resolve_gethostbyaddr_r; + _nss_resolve_gethostbyaddr2_r; +local: *; +}; diff --git a/src/resolve/resolved-bus.c b/src/resolve/resolved-bus.c index 50eb012f8..e73bdacbb 100644 --- a/src/resolve/resolved-bus.c +++ b/src/resolve/resolved-bus.c @@ -450,7 +450,7 @@ int manager_connect_bus(Manager *m) { return 0; } - r = sd_bus_add_object_vtable(m->bus, NULL, "/org/freedesktop/resolve1", "org.freedesktop.resolve1", resolve_vtable, m); + r = sd_bus_add_object_vtable(m->bus, NULL, "/org/freedesktop/resolve1", "org.freedesktop.resolve1.Manager", resolve_vtable, m); if (r < 0) { log_error("Failed to register object: %s", strerror(-r)); return r;