diff options
Diffstat (limited to 'src/libsystemd-network/src/sd-ndisc.c')
| -rw-r--r-- | src/libsystemd-network/src/sd-ndisc.c | 419 |
1 files changed, 419 insertions, 0 deletions
diff --git a/src/libsystemd-network/src/sd-ndisc.c b/src/libsystemd-network/src/sd-ndisc.c new file mode 100644 index 0000000000..7f3bcbd7e2 --- /dev/null +++ b/src/libsystemd-network/src/sd-ndisc.c @@ -0,0 +1,419 @@ +/*** + This file is part of systemd. + + Copyright (C) 2014 Intel Corporation. All rights reserved. + + 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/icmp6.h> +#include <netinet/in.h> + +#include "systemd-basic/alloc-util.h" +#include "systemd-basic/fd-util.h" +#include "systemd-basic/in-addr-util.h" +#include "systemd-basic/socket-util.h" +#include "systemd-basic/string-util.h" +#include "systemd-basic/util.h" +#include "systemd-network/icmp6-util.h" +#include "systemd-network/ndisc-internal.h" +#include "systemd-network/ndisc-router.h" +#include "systemd-network/sd-ndisc.h" + +#define NDISC_ROUTER_SOLICITATION_INTERVAL (4U * USEC_PER_SEC) +#define NDISC_MAX_ROUTER_SOLICITATIONS 3U + +static void ndisc_callback(sd_ndisc *ndisc, sd_ndisc_event event, sd_ndisc_router *rt) { + assert(ndisc); + + log_ndisc("Invoking callback for '%c'.", event); + + if (!ndisc->callback) + return; + + ndisc->callback(ndisc, event, rt, ndisc->userdata); +} + +_public_ int sd_ndisc_set_callback( + sd_ndisc *nd, + sd_ndisc_callback_t callback, + void *userdata) { + + assert_return(nd, -EINVAL); + + nd->callback = callback; + nd->userdata = userdata; + + return 0; +} + +_public_ int sd_ndisc_set_ifindex(sd_ndisc *nd, int ifindex) { + assert_return(nd, -EINVAL); + assert_return(ifindex > 0, -EINVAL); + assert_return(nd->fd < 0, -EBUSY); + + nd->ifindex = ifindex; + return 0; +} + +_public_ int sd_ndisc_set_mac(sd_ndisc *nd, const struct ether_addr *mac_addr) { + assert_return(nd, -EINVAL); + + if (mac_addr) + nd->mac_addr = *mac_addr; + else + zero(nd->mac_addr); + + return 0; +} + +_public_ int sd_ndisc_attach_event(sd_ndisc *nd, sd_event *event, int64_t priority) { + int r; + + assert_return(nd, -EINVAL); + assert_return(nd->fd < 0, -EBUSY); + assert_return(!nd->event, -EBUSY); + + if (event) + nd->event = sd_event_ref(event); + else { + r = sd_event_default(&nd->event); + if (r < 0) + return 0; + } + + nd->event_priority = priority; + + return 0; +} + +_public_ int sd_ndisc_detach_event(sd_ndisc *nd) { + + assert_return(nd, -EINVAL); + assert_return(nd->fd < 0, -EBUSY); + + nd->event = sd_event_unref(nd->event); + return 0; +} + +_public_ sd_event *sd_ndisc_get_event(sd_ndisc *nd) { + assert_return(nd, NULL); + + return nd->event; +} + +_public_ sd_ndisc *sd_ndisc_ref(sd_ndisc *nd) { + + if (!nd) + return NULL; + + assert(nd->n_ref > 0); + nd->n_ref++; + + return nd; +} + +static int ndisc_reset(sd_ndisc *nd) { + assert(nd); + + nd->timeout_event_source = sd_event_source_unref(nd->timeout_event_source); + nd->recv_event_source = sd_event_source_unref(nd->recv_event_source); + nd->fd = safe_close(nd->fd); + + return 0; +} + +_public_ sd_ndisc *sd_ndisc_unref(sd_ndisc *nd) { + + if (!nd) + return NULL; + + assert(nd->n_ref > 0); + nd->n_ref--; + + if (nd->n_ref > 0) + return NULL; + + ndisc_reset(nd); + sd_ndisc_detach_event(nd); + return mfree(nd); +} + +_public_ int sd_ndisc_new(sd_ndisc **ret) { + _cleanup_(sd_ndisc_unrefp) sd_ndisc *nd = NULL; + + assert_return(ret, -EINVAL); + + nd = new0(sd_ndisc, 1); + if (!nd) + return -ENOMEM; + + nd->n_ref = 1; + nd->fd = -1; + + *ret = nd; + nd = NULL; + + return 0; +} + +_public_ int sd_ndisc_get_mtu(sd_ndisc *nd, uint32_t *mtu) { + assert_return(nd, -EINVAL); + assert_return(mtu, -EINVAL); + + if (nd->mtu == 0) + return -ENODATA; + + *mtu = nd->mtu; + return 0; +} + +_public_ int sd_ndisc_get_hop_limit(sd_ndisc *nd, uint8_t *ret) { + assert_return(nd, -EINVAL); + assert_return(ret, -EINVAL); + + if (nd->hop_limit == 0) + return -ENODATA; + + *ret = nd->hop_limit; + return 0; +} + +static int ndisc_handle_datagram(sd_ndisc *nd, sd_ndisc_router *rt) { + int r; + + assert(nd); + assert(rt); + + r = ndisc_router_parse(rt); + if (r == -EBADMSG) /* Bad packet */ + return 0; + if (r < 0) + return 0; + + /* Update global variables we keep */ + if (rt->mtu > 0) + nd->mtu = rt->mtu; + if (rt->hop_limit > 0) + nd->hop_limit = rt->hop_limit; + + log_ndisc("Received Router Advertisement: flags %s preference %s lifetime %" PRIu16 " sec", + rt->flags & ND_RA_FLAG_MANAGED ? "MANAGED" : rt->flags & ND_RA_FLAG_OTHER ? "OTHER" : "none", + rt->preference == SD_NDISC_PREFERENCE_HIGH ? "high" : rt->preference == SD_NDISC_PREFERENCE_LOW ? "low" : "medium", + rt->lifetime); + + ndisc_callback(nd, SD_NDISC_EVENT_ROUTER, rt); + return 0; +} + +static int ndisc_recv(sd_event_source *s, int fd, uint32_t revents, void *userdata) { + _cleanup_(sd_ndisc_router_unrefp) sd_ndisc_router *rt = NULL; + sd_ndisc *nd = userdata; + union { + struct cmsghdr cmsghdr; + uint8_t buf[CMSG_SPACE(sizeof(int)) + /* ttl */ + CMSG_SPACE(sizeof(struct timeval))]; + } control = {}; + struct iovec iov = {}; + union sockaddr_union sa = {}; + struct msghdr msg = { + .msg_name = &sa.sa, + .msg_namelen = sizeof(sa), + .msg_iov = &iov, + .msg_iovlen = 1, + .msg_control = &control, + .msg_controllen = sizeof(control), + }; + struct cmsghdr *cmsg; + ssize_t len, buflen; + + assert(s); + assert(nd); + assert(nd->event); + + buflen = next_datagram_size_fd(fd); + if (buflen < 0) + return log_ndisc_errno(buflen, "Failed to determine datagram size to read: %m"); + + rt = ndisc_router_new(buflen); + if (!rt) + return -ENOMEM; + + iov.iov_base = NDISC_ROUTER_RAW(rt); + iov.iov_len = rt->raw_size; + + len = recvmsg(fd, &msg, MSG_DONTWAIT); + if (len < 0) { + if (errno == EAGAIN || errno == EINTR) + return 0; + + return log_ndisc_errno(errno, "Could not receive message from ICMPv6 socket: %m"); + } + + if ((size_t) len != rt->raw_size) { + log_ndisc("Packet size mismatch."); + return -EINVAL; + } + + if (msg.msg_namelen == sizeof(struct sockaddr_in6) && + sa.in6.sin6_family == AF_INET6) { + + if (in_addr_is_link_local(AF_INET6, (union in_addr_union*) &sa.in6.sin6_addr) <= 0) { + _cleanup_free_ char *addr = NULL; + + (void) in_addr_to_string(AF_INET6, (union in_addr_union*) &sa.in6.sin6_addr, &addr); + log_ndisc("Received RA from non-link-local address %s. Ignoring.", strna(addr)); + return 0; + } + + rt->address = sa.in6.sin6_addr; + + } else if (msg.msg_namelen > 0) { + log_ndisc("Received invalid source address size from ICMPv6 socket: %zu bytes", (size_t) msg.msg_namelen); + return -EINVAL; + } + + /* namelen == 0 only happens when running the test-suite over a socketpair */ + + assert(!(msg.msg_flags & MSG_CTRUNC)); + assert(!(msg.msg_flags & MSG_TRUNC)); + + CMSG_FOREACH(cmsg, &msg) { + if (cmsg->cmsg_level == SOL_IPV6 && + cmsg->cmsg_type == IPV6_HOPLIMIT && + cmsg->cmsg_len == CMSG_LEN(sizeof(int))) { + int hops = *(int*) CMSG_DATA(cmsg); + + if (hops != 255) { + log_ndisc("Received RA with invalid hop limit %d. Ignoring.", hops); + return 0; + } + } + + if (cmsg->cmsg_level == SOL_SOCKET && + cmsg->cmsg_type == SO_TIMESTAMP && + cmsg->cmsg_len == CMSG_LEN(sizeof(struct timeval))) + triple_timestamp_from_realtime(&rt->timestamp, timeval_load((struct timeval*) CMSG_DATA(cmsg))); + } + + if (!triple_timestamp_is_set(&rt->timestamp)) + triple_timestamp_get(&rt->timestamp); + + nd->timeout_event_source = sd_event_source_unref(nd->timeout_event_source); + + return ndisc_handle_datagram(nd, rt); +} + +static int ndisc_timeout(sd_event_source *s, uint64_t usec, void *userdata) { + sd_ndisc *nd = userdata; + usec_t time_now, next_timeout; + int r; + + assert(s); + assert(nd); + assert(nd->event); + + if (nd->nd_sent >= NDISC_MAX_ROUTER_SOLICITATIONS) { + nd->timeout_event_source = sd_event_source_unref(nd->timeout_event_source); + ndisc_callback(nd, SD_NDISC_EVENT_TIMEOUT, NULL); + return 0; + } + + r = icmp6_send_router_solicitation(nd->fd, &nd->mac_addr); + if (r < 0) { + log_ndisc_errno(r, "Error sending Router Solicitation: %m"); + goto fail; + } + + log_ndisc("Sent Router Solicitation"); + nd->nd_sent++; + + assert_se(sd_event_now(nd->event, clock_boottime_or_monotonic(), &time_now) >= 0); + next_timeout = time_now + NDISC_ROUTER_SOLICITATION_INTERVAL; + + r = sd_event_source_set_time(nd->timeout_event_source, next_timeout); + if (r < 0) { + log_ndisc_errno(r, "Error updating timer: %m"); + goto fail; + } + + r = sd_event_source_set_enabled(nd->timeout_event_source, SD_EVENT_ONESHOT); + if (r < 0) { + log_ndisc_errno(r, "Error reenabling timer: %m"); + goto fail; + } + + return 0; + +fail: + sd_ndisc_stop(nd); + return 0; +} + +_public_ int sd_ndisc_stop(sd_ndisc *nd) { + assert_return(nd, -EINVAL); + + if (nd->fd < 0) + return 0; + + log_ndisc("Stopping IPv6 Router Solicitation client"); + + ndisc_reset(nd); + return 1; +} + +_public_ int sd_ndisc_start(sd_ndisc *nd) { + int r; + + assert_return(nd, -EINVAL); + assert_return(nd->event, -EINVAL); + assert_return(nd->ifindex > 0, -EINVAL); + + if (nd->fd >= 0) + return 0; + + assert(!nd->recv_event_source); + assert(!nd->timeout_event_source); + + nd->fd = icmp6_bind_router_solicitation(nd->ifindex); + if (nd->fd < 0) + return nd->fd; + + r = sd_event_add_io(nd->event, &nd->recv_event_source, nd->fd, EPOLLIN, ndisc_recv, nd); + if (r < 0) + goto fail; + + r = sd_event_source_set_priority(nd->recv_event_source, nd->event_priority); + if (r < 0) + goto fail; + + (void) sd_event_source_set_description(nd->recv_event_source, "ndisc-receive-message"); + + r = sd_event_add_time(nd->event, &nd->timeout_event_source, clock_boottime_or_monotonic(), 0, 0, ndisc_timeout, nd); + if (r < 0) + goto fail; + + r = sd_event_source_set_priority(nd->timeout_event_source, nd->event_priority); + if (r < 0) + goto fail; + + (void) sd_event_source_set_description(nd->timeout_event_source, "ndisc-timeout"); + + log_ndisc("Started IPv6 Router Solicitation client"); + return 1; + +fail: + ndisc_reset(nd); + return r; +} |