+/*-*- 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 <http://www.gnu.org/licenses/>.
+***/
+
+#include <netinet/tcp.h>
+
+#include "missing.h"
+#include "resolved-dns-stream.h"
+
+#define DNS_STREAM_TIMEOUT_USEC (10 * USEC_PER_SEC)
+#define DNS_STREAMS_MAX 128
+
+static void dns_stream_stop(DnsStream *s) {
+ assert(s);
+
+ s->io_event_source = sd_event_source_unref(s->io_event_source);
+ s->timeout_event_source = sd_event_source_unref(s->timeout_event_source);
+ s->fd = safe_close(s->fd);
+}
+
+static int dns_stream_update_io(DnsStream *s) {
+ int f = 0;
+
+ assert(s);
+
+ if (s->write_packet && s->n_written < sizeof(s->write_size) + s->write_packet->size)
+ f |= EPOLLOUT;
+ if (!s->read_packet || s->n_read < sizeof(s->read_size) + s->read_packet->size)
+ f |= EPOLLIN;
+
+ return sd_event_source_set_io_events(s->io_event_source, f);
+}
+
+static int stream_complete(DnsStream *s, int error) {
+ assert(s);
+
+ dns_stream_stop(s);
+
+ if (s->complete)
+ s->complete(s, error);
+ else
+ dns_stream_free(s);
+
+ return 0;
+}
+
+static int on_stream_timeout(sd_event_source *es, usec_t usec, void *userdata) {
+ DnsStream *s = userdata;
+
+ assert(s);
+
+ return stream_complete(s, ETIMEDOUT);
+}
+
+static int on_stream_io(sd_event_source *es, int fd, uint32_t revents, void *userdata) {
+ DnsStream *s = userdata;
+ int r;
+
+ assert(s);
+
+ if ((revents & EPOLLOUT) &&
+ s->write_packet &&
+ s->n_written < sizeof(s->write_size) + s->write_packet->size) {
+
+ struct iovec iov[2];
+ ssize_t ss;
+
+ iov[0].iov_base = &s->write_size;
+ iov[0].iov_len = sizeof(s->write_size);
+ iov[1].iov_base = DNS_PACKET_DATA(s->write_packet);
+ iov[1].iov_len = s->write_packet->size;
+
+ IOVEC_INCREMENT(iov, 2, s->n_written);
+
+ ss = writev(fd, iov, 2);
+ if (ss < 0) {
+ if (errno != EINTR && errno != EAGAIN)
+ return stream_complete(s, errno);
+ } else
+ s->n_written += ss;
+
+ /* Are we done? If so, disable the event source for EPOLLOUT */
+ if (s->n_written >= sizeof(s->write_size) + s->write_packet->size) {
+ r = dns_stream_update_io(s);
+ if (r < 0)
+ return stream_complete(s, -r);
+ }
+ }
+
+ if ((revents & (EPOLLIN|EPOLLHUP|EPOLLRDHUP)) &&
+ (!s->read_packet ||
+ s->n_read < sizeof(s->read_size) + s->read_packet->size)) {
+
+ if (s->n_read < sizeof(s->read_size)) {
+ ssize_t ss;
+
+ ss = read(fd, (uint8_t*) &s->read_size + s->n_read, sizeof(s->read_size) - s->n_read);
+ if (ss < 0) {
+ if (errno != EINTR && errno != EAGAIN)
+ return stream_complete(s, errno);
+ } else if (ss == 0)
+ return stream_complete(s, ECONNRESET);
+ else
+ s->n_read += ss;
+ }
+
+ if (s->n_read >= sizeof(s->read_size)) {
+
+ if (be16toh(s->read_size) < DNS_PACKET_HEADER_SIZE)
+ return stream_complete(s, EBADMSG);
+
+ if (s->n_read < sizeof(s->read_size) + be16toh(s->read_size)) {
+ ssize_t ss;
+
+ if (!s->read_packet) {
+ r = dns_packet_new(&s->read_packet, s->protocol, be16toh(s->read_size));
+ if (r < 0)
+ return stream_complete(s, -r);
+
+ s->read_packet->size = be16toh(s->read_size);
+ s->read_packet->ipproto = IPPROTO_TCP;
+ s->read_packet->family = s->peer.sa.sa_family;
+ s->read_packet->ttl = s->ttl;
+ s->read_packet->ifindex = s->ifindex;
+
+ if (s->read_packet->family == AF_INET) {
+ s->read_packet->sender.in = s->peer.in.sin_addr;
+ s->read_packet->sender_port = be16toh(s->peer.in.sin_port);
+ s->read_packet->destination.in = s->local.in.sin_addr;
+ s->read_packet->destination_port = be16toh(s->local.in.sin_port);
+ } else {
+ assert(s->read_packet->family == AF_INET6);
+ s->read_packet->sender.in6 = s->peer.in6.sin6_addr;
+ s->read_packet->sender_port = be16toh(s->peer.in6.sin6_port);
+ s->read_packet->destination.in6 = s->local.in6.sin6_addr;
+ s->read_packet->destination_port = be16toh(s->local.in6.sin6_port);
+
+ if (s->read_packet->ifindex == 0)
+ s->read_packet->ifindex = s->peer.in6.sin6_scope_id;
+ if (s->read_packet->ifindex == 0)
+ s->read_packet->ifindex = s->local.in6.sin6_scope_id;
+ }
+ }
+
+ ss = read(fd,
+ (uint8_t*) DNS_PACKET_DATA(s->read_packet) + s->n_read - sizeof(s->read_size),
+ sizeof(s->read_size) + be16toh(s->read_size) - s->n_read);
+ if (ss < 0) {
+ if (errno != EINTR && errno != EAGAIN)
+ return stream_complete(s, errno);
+ } else if (ss == 0)
+ return stream_complete(s, ECONNRESET);
+ else
+ s->n_read += ss;
+ }
+
+ /* Are we done? If so, disable the event source for EPOLLIN */
+ if (s->n_read >= sizeof(s->read_size) + be16toh(s->read_size)) {
+ r = dns_stream_update_io(s);
+ if (r < 0)
+ return stream_complete(s, -r);
+
+ /* If there's a packet handler
+ * installed, call that. Note that
+ * this is optional... */
+ if (s->on_packet)
+ return s->on_packet(s);
+ }
+ }
+ }
+
+ if ((s->write_packet && s->n_written >= sizeof(s->write_size) + s->write_packet->size) &&
+ (s->read_packet && s->n_read >= sizeof(s->read_size) + s->read_packet->size))
+ return stream_complete(s, 0);
+
+ return 0;
+}
+
+DnsStream *dns_stream_free(DnsStream *s) {
+ if (!s)
+ return NULL;
+
+ dns_stream_stop(s);
+
+ if (s->manager) {
+ LIST_REMOVE(streams, s->manager->dns_streams, s);
+ s->manager->n_dns_streams--;
+ }
+
+ dns_packet_unref(s->write_packet);
+ dns_packet_unref(s->read_packet);
+
+ free(s);
+
+ return 0;
+}
+
+DEFINE_TRIVIAL_CLEANUP_FUNC(DnsStream*, dns_stream_free);
+
+int dns_stream_new(Manager *m, DnsStream **ret, DnsProtocol protocol, int fd) {
+ static const int one = 1;
+ union {
+ struct cmsghdr header; /* For alignment */
+ uint8_t buffer[CMSG_SPACE(MAX(sizeof(struct in_pktinfo), sizeof(struct in6_pktinfo)))
+ + EXTRA_CMSG_SPACE /* kernel appears to require extra space */];
+ } control;
+ struct msghdr mh = {};
+ struct cmsghdr *cmsg;
+ _cleanup_(dns_stream_freep) DnsStream *s = NULL;
+ socklen_t sl;
+ int r;
+
+ assert(m);
+ assert(fd >= 0);
+
+ if (m->n_dns_streams > DNS_STREAMS_MAX)
+ return -EBUSY;
+
+ s = new0(DnsStream, 1);
+ if (!s)
+ return -ENOMEM;
+
+ s->fd = -1;
+ s->protocol = protocol;
+
+ /* Query the remote side */
+ s->peer_salen = sizeof(s->peer);
+ r = getpeername(fd, &s->peer.sa, &s->peer_salen);
+ if (r < 0)
+ return -errno;
+ if (s->peer.sa.sa_family == AF_INET6)
+ s->ifindex = s->peer.in6.sin6_scope_id;
+
+ /* Query the local side */
+ s->local_salen = sizeof(s->local);
+ r = getsockname(fd, &s->local.sa, &s->local_salen);
+ if (r < 0)
+ return -errno;
+ if (s->local.sa.sa_family == AF_INET6 && s->ifindex <= 0)
+ s->ifindex = s->local.in6.sin6_scope_id;
+
+ /* Check consistency */
+ assert(s->peer.sa.sa_family == s->local.sa.sa_family);
+ assert(IN_SET(s->peer.sa.sa_family, AF_INET, AF_INET6));
+
+ /* Query connection meta information */
+ sl = sizeof(control);
+ if (s->peer.sa.sa_family == AF_INET) {
+ r = getsockopt(fd, IPPROTO_IP, IP_PKTOPTIONS, &control, &sl);
+ if (r < 0)
+ return -errno;
+ } else {
+ assert(s->peer.sa.sa_family == AF_INET6);
+
+ r = getsockopt(fd, IPPROTO_IPV6, IPV6_2292PKTOPTIONS, &control, &sl);
+ if (r < 0)
+ return -errno;
+ }
+
+ mh.msg_control = &control;
+ mh.msg_controllen = sl;
+ for (cmsg = CMSG_FIRSTHDR(&mh); cmsg; cmsg = CMSG_NXTHDR(&mh, cmsg)) {
+
+ if (cmsg->cmsg_level == IPPROTO_IPV6) {
+ assert(s->peer.sa.sa_family == AF_INET6);
+
+ switch (cmsg->cmsg_type) {
+
+ case IPV6_PKTINFO: {
+ struct in6_pktinfo *i = (struct in6_pktinfo*) CMSG_DATA(cmsg);
+
+ if (s->ifindex <= 0)
+ s->ifindex = i->ipi6_ifindex;
+ break;
+ }
+
+ case IPV6_HOPLIMIT:
+ s->ttl = *(int *) CMSG_DATA(cmsg);
+ break;
+ }
+
+ } else if (cmsg->cmsg_level == IPPROTO_IP) {
+ assert(s->peer.sa.sa_family == AF_INET);
+
+ switch (cmsg->cmsg_type) {
+
+ case IP_PKTINFO: {
+ struct in_pktinfo *i = (struct in_pktinfo*) CMSG_DATA(cmsg);
+
+ if (s->ifindex <= 0)
+ s->ifindex = i->ipi_ifindex;
+ break;
+ }
+
+ case IP_TTL:
+ s->ttl = *(int *) CMSG_DATA(cmsg);
+ break;
+ }
+ }
+ }
+
+ /* The Linux kernel sets the interface index to the loopback
+ * device if the connection came from the local host since it
+ * avoids the routing table in such a case. Let's unset the
+ * interface index in such a case. */
+ if (s->ifindex > 0 && manager_ifindex_is_loopback(m, s->ifindex) != 0)
+ s->ifindex = 0;
+
+ /* If we don't know the interface index still, we look for the
+ * first local interface with a matching address. Yuck! */
+ if (s->ifindex <= 0)
+ s->ifindex = manager_find_ifindex(m, s->local.sa.sa_family, s->local.sa.sa_family == AF_INET ? (union in_addr_union*) &s->local.in.sin_addr : (union in_addr_union*) &s->local.in6.sin6_addr);
+
+ r = setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &one, sizeof(one));
+ if (r < 0)
+ return -errno;
+
+ if (s->protocol == DNS_PROTOCOL_LLMNR && s->ifindex > 0) {
+ uint32_t ifindex = htobe32(s->ifindex);
+
+ /* Make sure all packets for this connection are sent on the same interface */
+ if (s->local.sa.sa_family == AF_INET) {
+ r = setsockopt(fd, IPPROTO_IP, IP_UNICAST_IF, &ifindex, sizeof(ifindex));
+ if (r < 0)
+ return -errno;
+ } else if (s->local.sa.sa_family == AF_INET6) {
+ r = setsockopt(fd, IPPROTO_IPV6, IPV6_UNICAST_IF, &ifindex, sizeof(ifindex));
+ if (r < 0)
+ return -errno;
+ }
+ }
+
+ r = sd_event_add_io(m->event, &s->io_event_source, fd, EPOLLIN, on_stream_io, s);
+ if (r < 0)
+ return r;
+
+ r = sd_event_add_time(m->event, &s->timeout_event_source, CLOCK_MONOTONIC, now(CLOCK_MONOTONIC) + DNS_STREAM_TIMEOUT_USEC, 0, on_stream_timeout, s);
+ if (r < 0)
+ return r;
+
+ LIST_PREPEND(streams, m->dns_streams, s);
+ s->manager = m;
+ s->fd = fd;
+ m->n_dns_streams++;
+
+ *ret = s;
+ s = NULL;
+
+ return 0;
+}
+
+int dns_stream_write_packet(DnsStream *s, DnsPacket *p) {
+ assert(s);
+
+ if (s->write_packet)
+ return -EBUSY;
+
+ s->write_packet = dns_packet_ref(p);
+ s->write_size = htobe16(p->size);
+ s->n_written = 0;
+
+ return dns_stream_update_io(s);
+}
~ianmdlvl / elogind.git / commitdiff