From 1716f6dcf54d4c181c2e2558e3d5414f54c8d9ca Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Fri, 18 Jul 2014 12:34:02 +0200 Subject: resolved: add LLMNR support for looking up names --- src/resolve/resolved-manager.c | 413 +++++++++++++++++++++++++++++++---------- 1 file changed, 315 insertions(+), 98 deletions(-) (limited to 'src/resolve/resolved-manager.c') diff --git a/src/resolve/resolved-manager.c b/src/resolve/resolved-manager.c index fed9a77973..9f44bf1204 100644 --- a/src/resolve/resolved-manager.c +++ b/src/resolve/resolved-manager.c @@ -21,7 +21,7 @@ #include #include -#include +#include #include #include #include @@ -392,6 +392,9 @@ int manager_new(Manager **ret) { return -ENOMEM; m->dns_ipv4_fd = m->dns_ipv6_fd = -1; + m->llmnr_ipv4_udp_fd = m->llmnr_ipv6_udp_fd = -1; + + m->use_llmnr = true; r = parse_dns_server_string(m, /* "172.31.0.125 2001:4860:4860::8888 2001:4860:4860::8889" */ DNS_SERVERS); if (r < 0) @@ -406,7 +409,7 @@ int manager_new(Manager **ret) { sd_event_set_watchdog(m->event, true); - r = dns_scope_new(m, &m->unicast_scope, DNS_SCOPE_DNS); + r = dns_scope_new(m, &m->unicast_scope, NULL, DNS_PROTOCOL_DNS, AF_UNSPEC); if (r < 0) return r; @@ -453,10 +456,14 @@ Manager *manager_free(Manager *m) { sd_event_source_unref(m->dns_ipv4_event_source); sd_event_source_unref(m->dns_ipv6_event_source); - safe_close(m->dns_ipv4_fd); safe_close(m->dns_ipv6_fd); + sd_event_source_unref(m->llmnr_ipv4_udp_event_source); + sd_event_source_unref(m->llmnr_ipv6_udp_event_source); + safe_close(m->llmnr_ipv4_udp_fd); + safe_close(m->llmnr_ipv6_udp_fd); + sd_event_source_unref(m->bus_retry_event_source); sd_bus_unref(m->bus); @@ -475,7 +482,7 @@ static void write_resolve_conf_server(DnsServer *s, FILE *f, unsigned *count) { assert(count); r = in_addr_to_string(s->family, &s->address, &t); - if (r < 0) { + if (r < 0) { log_warning("Invalid DNS address. Ignoring."); return; } @@ -539,35 +546,44 @@ fail: return r; } -int manager_dns_ipv4_recv(Manager *m, DnsPacket **ret) { +int manager_recv(Manager *m, int fd, DnsProtocol protocol, DnsPacket **ret) { _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; + union { + struct cmsghdr header; /* For alignment */ + uint8_t buffer[CMSG_SPACE(MAX(sizeof(struct in_pktinfo), sizeof(struct in6_pktinfo))) + + CMSG_SPACE(int) /* ttl/hoplimit */ + + 1024 /* kernel appears to require extra buffer space */]; + } control; + union sockaddr_union sa; struct msghdr mh = {}; - int fd, ms = 0, r; + struct cmsghdr *cmsg; struct iovec iov; + int ms = 0, r; ssize_t l; assert(m); + assert(fd >= 0); assert(ret); - fd = manager_dns_ipv4_fd(m); - if (fd < 0) - return fd; - r = ioctl(fd, FIONREAD, &ms); if (r < 0) return -errno; if (ms < 0) return -EIO; - r = dns_packet_new(&p, ms); + r = dns_packet_new(&p, protocol, ms); if (r < 0) return r; iov.iov_base = DNS_PACKET_DATA(p); iov.iov_len = p->allocated; + mh.msg_name = &sa.sa; + mh.msg_namelen = sizeof(sa); mh.msg_iov = &iov; mh.msg_iovlen = 1; + mh.msg_control = &control; + mh.msg_controllen = sizeof(control); l = recvmsg(fd, &mh, 0); if (l < 0) { @@ -580,56 +596,58 @@ int manager_dns_ipv4_recv(Manager *m, DnsPacket **ret) { if (l <= 0) return -EIO; + assert(!(mh.msg_flags & MSG_CTRUNC)); + assert(!(mh.msg_flags & MSG_TRUNC)); + p->size = (size_t) l; - *ret = p; - p = NULL; + p->family = sa.sa.sa_family; + if (p->family == AF_INET) + p->sender.in = sa.in.sin_addr; + else if (p->family == AF_INET6) + p->sender.in6 = sa.in6.sin6_addr; + else + return -EAFNOSUPPORT; - return 1; -} + for (cmsg = CMSG_FIRSTHDR(&mh); cmsg; cmsg = CMSG_NXTHDR(&mh, cmsg)) { -int manager_dns_ipv6_recv(Manager *m, DnsPacket **ret) { - _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; - struct msghdr mh = {}; - struct iovec iov; - int fd, ms = 0, r; - ssize_t l; + if (cmsg->cmsg_level == IPPROTO_IPV6) { + assert(p->family == AF_INET6); - assert(m); - assert(ret); + switch (cmsg->cmsg_type) { - fd = manager_dns_ipv6_fd(m); - if (fd < 0) - return fd; + case IPV6_PKTINFO: { + struct in6_pktinfo *i = (struct in6_pktinfo*) CMSG_DATA(cmsg); - r = ioctl(fd, FIONREAD, &ms); - if (r < 0) - return -errno; - if (ms < 0) - return -EIO; + p->ifindex = i->ipi6_ifindex; + p->destination.in6 = i->ipi6_addr; + break; + } - r = dns_packet_new(&p, ms); - if (r < 0) - return r; + case IPV6_HOPLIMIT: + p->ttl = *(int *) CMSG_DATA(cmsg); + break; - iov.iov_base = DNS_PACKET_DATA(p); - iov.iov_len = p->allocated; + } + } else if (cmsg->cmsg_level == IPPROTO_IP) { + assert(p->family == AF_INET); - mh.msg_iov = &iov; - mh.msg_iovlen = 1; - - l = recvmsg(fd, &mh, 0); - if (l < 0) { - if (errno == EAGAIN || errno == EINTR) - return 0; + switch (cmsg->cmsg_type) { - return -errno; - } + case IP_PKTINFO: { + struct in_pktinfo *i = (struct in_pktinfo*) CMSG_DATA(cmsg); - if (l <= 0) - return -EIO; + p->ifindex = i->ipi_ifindex; + p->destination.in = i->ipi_addr; + break; + } - p->size = (size_t) l; + case IP_RECVTTL: + p->ttl = *(int *) CMSG_DATA(cmsg); + break; + } + } + } *ret = p; p = NULL; @@ -637,43 +655,30 @@ int manager_dns_ipv6_recv(Manager *m, DnsPacket **ret) { return 1; } -static int on_dns_ipv4_packet(sd_event_source *s, int fd, uint32_t revents, void *userdata) { +static int on_dns_packet(sd_event_source *s, int fd, uint32_t revents, void *userdata) { _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; DnsQueryTransaction *t = NULL; Manager *m = userdata; int r; - r = manager_dns_ipv4_recv(m, &p); + r = manager_recv(m, fd, DNS_PROTOCOL_DNS, &p); if (r <= 0) return r; - t = hashmap_get(m->dns_query_transactions, UINT_TO_PTR(DNS_PACKET_ID(p))); - if (!t) - return 0; - - dns_query_transaction_reply(t, p); - return 0; -} - -static int on_dns_ipv6_packet(sd_event_source *s, int fd, uint32_t revents, void *userdata) { - _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; - DnsQueryTransaction *t = NULL; - Manager *m = userdata; - int r; - - r = manager_dns_ipv6_recv(m, &p); - if (r <= 0) - return r; + if (dns_packet_validate_reply(p) >= 0) { + t = hashmap_get(m->dns_query_transactions, UINT_TO_PTR(DNS_PACKET_ID(p))); + if (!t) + return 0; - t = hashmap_get(m->dns_query_transactions, UINT_TO_PTR(DNS_PACKET_ID(p))); - if (!t) - return 0; + dns_query_transaction_reply(t, p); + } else + log_debug("Invalid reply packet."); - dns_query_transaction_reply(t, p); return 0; } int manager_dns_ipv4_fd(Manager *m) { + const int one = 1; int r; assert(m); @@ -685,14 +690,25 @@ int manager_dns_ipv4_fd(Manager *m) { if (m->dns_ipv4_fd < 0) return -errno; - r = sd_event_add_io(m->event, &m->dns_ipv4_event_source, m->dns_ipv4_fd, EPOLLIN, on_dns_ipv4_packet, m); + r = setsockopt(m->dns_ipv4_fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = sd_event_add_io(m->event, &m->dns_ipv4_event_source, m->dns_ipv4_fd, EPOLLIN, on_dns_packet, m); if (r < 0) - return r; + goto fail; return m->dns_ipv4_fd; + +fail: + m->dns_ipv4_fd = safe_close(m->dns_ipv4_fd); + return r; } int manager_dns_ipv6_fd(Manager *m) { + const int one = 1; int r; assert(m); @@ -704,11 +720,21 @@ int manager_dns_ipv6_fd(Manager *m) { if (m->dns_ipv6_fd < 0) return -errno; - r = sd_event_add_io(m->event, &m->dns_ipv6_event_source, m->dns_ipv6_fd, EPOLLIN, on_dns_ipv6_packet, m); + r = setsockopt(m->dns_ipv6_fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = sd_event_add_io(m->event, &m->dns_ipv6_event_source, m->dns_ipv6_fd, EPOLLIN, on_dns_packet, m); if (r < 0) - return r; + goto fail; return m->dns_ipv6_fd; + +fail: + m->dns_ipv6_fd = safe_close(m->dns_ipv6_fd); + return r; } static int sendmsg_loop(int fd, struct msghdr *mh, int flags) { @@ -735,28 +761,28 @@ static int sendmsg_loop(int fd, struct msghdr *mh, int flags) { } } -int manager_dns_ipv4_send(Manager *m, DnsServer *srv, int ifindex, DnsPacket *p) { +static int manager_ipv4_send(Manager *m, int fd, int ifindex, struct in_addr *addr, uint16_t port, DnsPacket *p) { union sockaddr_union sa = { .in.sin_family = AF_INET, - .in.sin_port = htobe16(53), }; + union { + struct cmsghdr header; /* For alignment */ + uint8_t buffer[CMSG_SPACE(sizeof(struct in_pktinfo))]; + } control; struct msghdr mh = {}; struct iovec iov; - uint8_t control[CMSG_SPACE(sizeof(struct in_pktinfo))]; - int fd; assert(m); - assert(srv); + assert(fd >= 0); + assert(addr); + assert(port > 0); assert(p); - fd = manager_dns_ipv4_fd(m); - if (fd < 0) - return fd; - iov.iov_base = DNS_PACKET_DATA(p); iov.iov_len = p->size; - sa.in.sin_addr = srv->address.in; + sa.in.sin_addr = *addr; + sa.in.sin_port = htobe16(port), mh.msg_iov = &iov; mh.msg_iovlen = 1; @@ -769,7 +795,7 @@ int manager_dns_ipv4_send(Manager *m, DnsServer *srv, int ifindex, DnsPacket *p) zero(control); - mh.msg_control = control; + mh.msg_control = &control; mh.msg_controllen = CMSG_LEN(sizeof(struct in_pktinfo)); cmsg = CMSG_FIRSTHDR(&mh); @@ -784,29 +810,28 @@ int manager_dns_ipv4_send(Manager *m, DnsServer *srv, int ifindex, DnsPacket *p) return sendmsg_loop(fd, &mh, 0); } -int manager_dns_ipv6_send(Manager *m, DnsServer *srv, int ifindex, DnsPacket *p) { +static int manager_ipv6_send(Manager *m, int fd, int ifindex, struct in6_addr *addr, uint16_t port, DnsPacket *p) { union sockaddr_union sa = { .in6.sin6_family = AF_INET6, - .in6.sin6_port = htobe16(53), }; - + union { + struct cmsghdr header; /* For alignment */ + uint8_t buffer[CMSG_SPACE(sizeof(struct in6_pktinfo))]; + } control; struct msghdr mh = {}; struct iovec iov; - uint8_t control[CMSG_SPACE(sizeof(struct in6_pktinfo))]; - int fd; assert(m); - assert(srv); + assert(fd >= 0); + assert(addr); + assert(port > 0); assert(p); - fd = manager_dns_ipv6_fd(m); - if (fd < 0) - return fd; - iov.iov_base = DNS_PACKET_DATA(p); iov.iov_len = p->size; - sa.in6.sin6_addr = srv->address.in6; + sa.in6.sin6_addr = *addr; + sa.in6.sin6_port = htobe16(port), sa.in6.sin6_scope_id = ifindex; mh.msg_iov = &iov; @@ -820,7 +845,7 @@ int manager_dns_ipv6_send(Manager *m, DnsServer *srv, int ifindex, DnsPacket *p) zero(control); - mh.msg_control = control; + mh.msg_control = &control; mh.msg_controllen = CMSG_LEN(sizeof(struct in6_pktinfo)); cmsg = CMSG_FIRSTHDR(&mh); @@ -835,6 +860,22 @@ int manager_dns_ipv6_send(Manager *m, DnsServer *srv, int ifindex, DnsPacket *p) return sendmsg_loop(fd, &mh, 0); } +int manager_send(Manager *m, int fd, int ifindex, unsigned char family, union in_addr_union *addr, uint16_t port, DnsPacket *p) { + assert(m); + assert(fd >= 0); + assert(addr); + assert(port > 0); + assert(p); + + if (family == AF_INET) + return manager_ipv4_send(m, fd, ifindex, &addr->in, port, p); + else if (family == AF_INET6) + return manager_ipv6_send(m, fd, ifindex, &addr->in6, port, p); + + return -EAFNOSUPPORT; +} + + DnsServer* manager_find_dns_server(Manager *m, unsigned char family, union in_addr_union *in_addr) { DnsServer *s; @@ -898,3 +939,179 @@ uint32_t manager_find_mtu(Manager *m) { return mtu; } + +static int on_llmnr_packet(sd_event_source *s, int fd, uint32_t revents, void *userdata) { + _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; + DnsQueryTransaction *t = NULL; + Manager *m = userdata; + int r; + + r = manager_recv(m, fd, DNS_PROTOCOL_LLMNR, &p); + if (r <= 0) + return r; + + if (dns_packet_validate_reply(p) >= 0) { + t = hashmap_get(m->dns_query_transactions, UINT_TO_PTR(DNS_PACKET_ID(p))); + if (!t) + return 0; + + dns_query_transaction_reply(t, p); + } + + return 0; +} + +int manager_llmnr_ipv4_udp_fd(Manager *m) { + union sockaddr_union sa = { + .in.sin_family = AF_INET, + .in.sin_port = htobe16(5355), + }; + static const int one = 1, pmtu = IP_PMTUDISC_DONT; + int r; + + assert(m); + + if (m->llmnr_ipv4_udp_fd >= 0) + return m->llmnr_ipv4_udp_fd; + + m->llmnr_ipv4_udp_fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); + if (m->llmnr_ipv4_udp_fd < 0) + return -errno; + + r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_TTL, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_MULTICAST_TTL, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_MULTICAST_LOOP, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->llmnr_ipv4_udp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_PKTINFO, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_RECVTTL, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + /* Disable Don't-Fragment bit in the IP header */ + r = setsockopt(m->llmnr_ipv4_udp_fd, IPPROTO_IP, IP_MTU_DISCOVER, &pmtu, sizeof(pmtu)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = bind(m->llmnr_ipv4_udp_fd, &sa.sa, sizeof(sa.in)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = sd_event_add_io(m->event, &m->llmnr_ipv4_udp_event_source, m->llmnr_ipv4_udp_fd, EPOLLIN, on_llmnr_packet, m); + if (r < 0) + goto fail; + + return m->llmnr_ipv4_udp_fd; + +fail: + m->llmnr_ipv4_udp_fd = safe_close(m->llmnr_ipv4_udp_fd); + return r; +} + +int manager_llmnr_ipv6_udp_fd(Manager *m) { + union sockaddr_union sa = { + .in6.sin6_family = AF_INET6, + .in6.sin6_port = htobe16(5355), + }; + static const int one = 1; + int r; + + assert(m); + + if (m->llmnr_ipv6_udp_fd >= 0) + return m->llmnr_ipv6_udp_fd; + + m->llmnr_ipv6_udp_fd = socket(AF_INET6, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); + if (m->llmnr_ipv6_udp_fd < 0) + return -errno; + + r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_V6ONLY, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->llmnr_ipv6_udp_fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = setsockopt(m->llmnr_ipv6_udp_fd, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &one, sizeof(one)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = bind(m->llmnr_ipv6_udp_fd, &sa.sa, sizeof(sa.in6)); + if (r < 0) { + r = -errno; + goto fail; + } + + r = sd_event_add_io(m->event, &m->llmnr_ipv6_udp_event_source, m->llmnr_ipv6_udp_fd, EPOLLIN, on_llmnr_packet, m); + if (r < 0) { + r = -errno; + goto fail; + } + + return m->llmnr_ipv6_udp_fd; + +fail: + m->llmnr_ipv6_udp_fd = safe_close(m->llmnr_ipv6_udp_fd); + return r; +} -- cgit v1.2.3-54-g00ecf