diff options
Diffstat (limited to 'src/libsystemd-network/sd-radv.c')
| -rw-r--r-- | src/libsystemd-network/sd-radv.c | 771 |
1 files changed, 771 insertions, 0 deletions
diff --git a/src/libsystemd-network/sd-radv.c b/src/libsystemd-network/sd-radv.c new file mode 100644 index 0000000..098e01f --- /dev/null +++ b/src/libsystemd-network/sd-radv.c @@ -0,0 +1,771 @@ +/* SPDX-License-Identifier: LGPL-2.1+ */ +/*** + Copyright © 2017 Intel Corporation. All rights reserved. +***/ + +#include <netinet/icmp6.h> +#include <netinet/in.h> +#include <arpa/inet.h> + +#include "sd-radv.h" + +#include "alloc-util.h" +#include "dns-domain.h" +#include "ether-addr-util.h" +#include "event-util.h" +#include "fd-util.h" +#include "icmp6-util.h" +#include "in-addr-util.h" +#include "io-util.h" +#include "macro.h" +#include "radv-internal.h" +#include "random-util.h" +#include "socket-util.h" +#include "string-util.h" +#include "strv.h" +#include "util.h" + +_public_ int sd_radv_new(sd_radv **ret) { + _cleanup_(sd_radv_unrefp) sd_radv *ra = NULL; + + assert_return(ret, -EINVAL); + + ra = new(sd_radv, 1); + if (!ra) + return -ENOMEM; + + *ra = (sd_radv) { + .n_ref = 1, + .fd = -1, + }; + + *ret = TAKE_PTR(ra); + + return 0; +} + +_public_ int sd_radv_attach_event(sd_radv *ra, sd_event *event, int64_t priority) { + int r; + + assert_return(ra, -EINVAL); + assert_return(!ra->event, -EBUSY); + + if (event) + ra->event = sd_event_ref(event); + else { + r = sd_event_default(&ra->event); + if (r < 0) + return 0; + } + + ra->event_priority = priority; + + return 0; +} + +_public_ int sd_radv_detach_event(sd_radv *ra) { + + assert_return(ra, -EINVAL); + + ra->event = sd_event_unref(ra->event); + return 0; +} + +_public_ sd_event *sd_radv_get_event(sd_radv *ra) { + assert_return(ra, NULL); + + return ra->event; +} + +static void radv_reset(sd_radv *ra) { + assert(ra); + + (void) event_source_disable(ra->timeout_event_source); + + ra->recv_event_source = + sd_event_source_unref(ra->recv_event_source); + + ra->ra_sent = 0; +} + +static sd_radv *radv_free(sd_radv *ra) { + if (!ra) + return NULL; + + while (ra->prefixes) { + sd_radv_prefix *p = ra->prefixes; + + LIST_REMOVE(prefix, ra->prefixes, p); + sd_radv_prefix_unref(p); + } + + free(ra->rdnss); + free(ra->dnssl); + + ra->timeout_event_source = sd_event_source_unref(ra->timeout_event_source); + + radv_reset(ra); + + sd_radv_detach_event(ra); + + ra->fd = safe_close(ra->fd); + + return mfree(ra); +} + +DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv, sd_radv, radv_free); + +static int radv_send(sd_radv *ra, const struct in6_addr *dst, uint32_t router_lifetime) { + sd_radv_prefix *p; + struct sockaddr_in6 dst_addr = { + .sin6_family = AF_INET6, + .sin6_addr = IN6ADDR_ALL_NODES_MULTICAST_INIT, + }; + struct nd_router_advert adv = {}; + struct { + struct nd_opt_hdr opthdr; + struct ether_addr slladdr; + } _packed_ opt_mac = { + .opthdr = { + .nd_opt_type = ND_OPT_SOURCE_LINKADDR, + .nd_opt_len = (sizeof(struct nd_opt_hdr) + + sizeof(struct ether_addr) - 1) /8 + 1, + }, + }; + struct nd_opt_mtu opt_mtu = { + .nd_opt_mtu_type = ND_OPT_MTU, + .nd_opt_mtu_len = 1, + }; + /* Reserve iov space for RA header, linkaddr, MTU, N prefixes, RDNSS + and DNSSL */ + struct iovec iov[5 + ra->n_prefixes]; + struct msghdr msg = { + .msg_name = &dst_addr, + .msg_namelen = sizeof(dst_addr), + .msg_iov = iov, + }; + usec_t time_now; + int r; + + assert(ra); + + r = sd_event_now(ra->event, clock_boottime_or_monotonic(), &time_now); + if (r < 0) + return r; + + if (dst && !IN6_IS_ADDR_UNSPECIFIED(dst)) + dst_addr.sin6_addr = *dst; + + adv.nd_ra_type = ND_ROUTER_ADVERT; + adv.nd_ra_curhoplimit = ra->hop_limit; + adv.nd_ra_flags_reserved = ra->flags; + adv.nd_ra_router_lifetime = htobe16(router_lifetime); + iov[msg.msg_iovlen++] = IOVEC_MAKE(&adv, sizeof(adv)); + + /* MAC address is optional, either because the link does not use L2 + addresses or load sharing is desired. See RFC 4861, Section 4.2 */ + if (!ether_addr_is_null(&ra->mac_addr)) { + opt_mac.slladdr = ra->mac_addr; + iov[msg.msg_iovlen++] = IOVEC_MAKE(&opt_mac, sizeof(opt_mac)); + } + + if (ra->mtu) { + opt_mtu.nd_opt_mtu_mtu = htobe32(ra->mtu); + iov[msg.msg_iovlen++] = IOVEC_MAKE(&opt_mtu, sizeof(opt_mtu)); + } + + LIST_FOREACH(prefix, p, ra->prefixes) { + if (p->valid_until) { + + if (time_now > p->valid_until) + p->opt.valid_lifetime = 0; + else + p->opt.valid_lifetime = htobe32((p->valid_until - time_now) / USEC_PER_SEC); + + if (time_now > p->preferred_until) + p->opt.preferred_lifetime = 0; + else + p->opt.preferred_lifetime = htobe32((p->preferred_until - time_now) / USEC_PER_SEC); + } + iov[msg.msg_iovlen++] = IOVEC_MAKE(&p->opt, sizeof(p->opt)); + } + + if (ra->rdnss) + iov[msg.msg_iovlen++] = IOVEC_MAKE(ra->rdnss, ra->rdnss->length * 8); + + if (ra->dnssl) + iov[msg.msg_iovlen++] = IOVEC_MAKE(ra->dnssl, ra->dnssl->length * 8); + + if (sendmsg(ra->fd, &msg, 0) < 0) + return -errno; + + return 0; +} + +static int radv_recv(sd_event_source *s, int fd, uint32_t revents, void *userdata) { + sd_radv *ra = userdata; + _cleanup_free_ char *addr = NULL; + struct in6_addr src; + triple_timestamp timestamp; + int r; + ssize_t buflen; + _cleanup_free_ char *buf = NULL; + + assert(s); + assert(ra); + assert(ra->event); + + buflen = next_datagram_size_fd(fd); + if (buflen < 0) + return (int) buflen; + + buf = new0(char, buflen); + if (!buf) + return -ENOMEM; + + r = icmp6_receive(fd, buf, buflen, &src, ×tamp); + if (r < 0) { + switch (r) { + case -EADDRNOTAVAIL: + (void) in_addr_to_string(AF_INET6, (union in_addr_union*) &src, &addr); + log_radv("Received RS from non-link-local address %s. Ignoring", addr); + break; + + case -EMULTIHOP: + log_radv("Received RS with invalid hop limit. Ignoring."); + break; + + case -EPFNOSUPPORT: + log_radv("Received invalid source address from ICMPv6 socket. Ignoring."); + break; + + case -EAGAIN: /* ignore spurious wakeups */ + break; + + default: + log_radv_errno(r, "Unexpected error receiving from ICMPv6 socket: %m"); + break; + } + + return 0; + } + + if ((size_t) buflen < sizeof(struct nd_router_solicit)) { + log_radv("Too short packet received"); + return 0; + } + + (void) in_addr_to_string(AF_INET6, (union in_addr_union*) &src, &addr); + + r = radv_send(ra, &src, ra->lifetime); + if (r < 0) + log_radv_errno(r, "Unable to send solicited Router Advertisement to %s: %m", strnull(addr)); + else + log_radv("Sent solicited Router Advertisement to %s", strnull(addr)); + + return 0; +} + +static usec_t radv_compute_timeout(usec_t min, usec_t max) { + assert_return(min <= max, SD_RADV_DEFAULT_MIN_TIMEOUT_USEC); + + return min + (random_u32() % (max - min)); +} + +static int radv_timeout(sd_event_source *s, uint64_t usec, void *userdata) { + int r; + sd_radv *ra = userdata; + usec_t min_timeout = SD_RADV_DEFAULT_MIN_TIMEOUT_USEC; + usec_t max_timeout = SD_RADV_DEFAULT_MAX_TIMEOUT_USEC; + usec_t time_now, timeout; + char time_string[FORMAT_TIMESPAN_MAX]; + + assert(s); + assert(ra); + assert(ra->event); + + r = sd_event_now(ra->event, clock_boottime_or_monotonic(), &time_now); + if (r < 0) + goto fail; + + r = radv_send(ra, NULL, ra->lifetime); + if (r < 0) + log_radv_errno(r, "Unable to send Router Advertisement: %m"); + + /* RFC 4861, Section 6.2.4, sending initial Router Advertisements */ + if (ra->ra_sent < SD_RADV_MAX_INITIAL_RTR_ADVERTISEMENTS) { + max_timeout = SD_RADV_MAX_INITIAL_RTR_ADVERT_INTERVAL_USEC; + min_timeout = SD_RADV_MAX_INITIAL_RTR_ADVERT_INTERVAL_USEC / 3; + } + + timeout = radv_compute_timeout(min_timeout, max_timeout); + + log_radv("Next Router Advertisement in %s", + format_timespan(time_string, FORMAT_TIMESPAN_MAX, + timeout, USEC_PER_SEC)); + + r = event_reset_time(ra->event, &ra->timeout_event_source, + clock_boottime_or_monotonic(), + time_now + timeout, MSEC_PER_SEC, + radv_timeout, ra, + ra->event_priority, "radv-timeout", true); + if (r < 0) + goto fail; + + ra->ra_sent++; + + return 0; + +fail: + sd_radv_stop(ra); + + return 0; +} + +_public_ int sd_radv_stop(sd_radv *ra) { + int r; + + assert_return(ra, -EINVAL); + + if (ra->state == SD_RADV_STATE_IDLE) + return 0; + + log_radv("Stopping IPv6 Router Advertisement daemon"); + + /* RFC 4861, Section 6.2.5, send at least one Router Advertisement + with zero lifetime */ + r = radv_send(ra, NULL, 0); + if (r < 0) + log_radv_errno(r, "Unable to send last Router Advertisement with router lifetime set to zero: %m"); + + radv_reset(ra); + ra->fd = safe_close(ra->fd); + ra->state = SD_RADV_STATE_IDLE; + + return 0; +} + +_public_ int sd_radv_start(sd_radv *ra) { + int r; + + assert_return(ra, -EINVAL); + assert_return(ra->event, -EINVAL); + assert_return(ra->ifindex > 0, -EINVAL); + + if (ra->state != SD_RADV_STATE_IDLE) + return 0; + + r = event_reset_time(ra->event, &ra->timeout_event_source, + clock_boottime_or_monotonic(), + 0, 0, + radv_timeout, ra, + ra->event_priority, "radv-timeout", true); + if (r < 0) + goto fail; + + r = icmp6_bind_router_advertisement(ra->ifindex); + if (r < 0) + goto fail; + + ra->fd = r; + + r = sd_event_add_io(ra->event, &ra->recv_event_source, ra->fd, EPOLLIN, radv_recv, ra); + if (r < 0) + goto fail; + + r = sd_event_source_set_priority(ra->recv_event_source, ra->event_priority); + if (r < 0) + goto fail; + + (void) sd_event_source_set_description(ra->recv_event_source, "radv-receive-message"); + + ra->state = SD_RADV_STATE_ADVERTISING; + + log_radv("Started IPv6 Router Advertisement daemon"); + + return 0; + + fail: + radv_reset(ra); + + return r; +} + +_public_ int sd_radv_set_ifindex(sd_radv *ra, int ifindex) { + assert_return(ra, -EINVAL); + assert_return(ifindex >= -1, -EINVAL); + + if (ra->state != SD_RADV_STATE_IDLE) + return -EBUSY; + + ra->ifindex = ifindex; + + return 0; +} + +_public_ int sd_radv_set_mac(sd_radv *ra, const struct ether_addr *mac_addr) { + assert_return(ra, -EINVAL); + + if (ra->state != SD_RADV_STATE_IDLE) + return -EBUSY; + + if (mac_addr) + ra->mac_addr = *mac_addr; + else + zero(ra->mac_addr); + + return 0; +} + +_public_ int sd_radv_set_mtu(sd_radv *ra, uint32_t mtu) { + assert_return(ra, -EINVAL); + assert_return(mtu >= 1280, -EINVAL); + + ra->mtu = mtu; + + return 0; +} + +_public_ int sd_radv_set_hop_limit(sd_radv *ra, uint8_t hop_limit) { + assert_return(ra, -EINVAL); + + if (ra->state != SD_RADV_STATE_IDLE) + return -EBUSY; + + ra->hop_limit = hop_limit; + + return 0; +} + +_public_ int sd_radv_set_router_lifetime(sd_radv *ra, uint32_t router_lifetime) { + assert_return(ra, -EINVAL); + + if (ra->state != SD_RADV_STATE_IDLE) + return -EBUSY; + + /* RFC 4191, Section 2.2, "...If the Router Lifetime is zero, the + preference value MUST be set to (00) by the sender..." */ + if (router_lifetime == 0 && + (ra->flags & (0x3 << 3)) != (SD_NDISC_PREFERENCE_MEDIUM << 3)) + return -ETIME; + + ra->lifetime = router_lifetime; + + return 0; +} + +_public_ int sd_radv_set_managed_information(sd_radv *ra, int managed) { + assert_return(ra, -EINVAL); + + if (ra->state != SD_RADV_STATE_IDLE) + return -EBUSY; + + SET_FLAG(ra->flags, ND_RA_FLAG_MANAGED, managed); + + return 0; +} + +_public_ int sd_radv_set_other_information(sd_radv *ra, int other) { + assert_return(ra, -EINVAL); + + if (ra->state != SD_RADV_STATE_IDLE) + return -EBUSY; + + SET_FLAG(ra->flags, ND_RA_FLAG_OTHER, other); + + return 0; +} + +_public_ int sd_radv_set_preference(sd_radv *ra, unsigned preference) { + int r = 0; + + assert_return(ra, -EINVAL); + assert_return(IN_SET(preference, + SD_NDISC_PREFERENCE_LOW, + SD_NDISC_PREFERENCE_MEDIUM, + SD_NDISC_PREFERENCE_HIGH), -EINVAL); + + ra->flags = (ra->flags & ~(0x3 << 3)) | (preference << 3); + + return r; +} + +_public_ int sd_radv_add_prefix(sd_radv *ra, sd_radv_prefix *p, int dynamic) { + sd_radv_prefix *cur; + int r; + _cleanup_free_ char *addr_p = NULL; + char time_string_preferred[FORMAT_TIMESPAN_MAX]; + char time_string_valid[FORMAT_TIMESPAN_MAX]; + usec_t time_now, valid, preferred, valid_until, preferred_until; + + assert_return(ra, -EINVAL); + + if (!p) + return -EINVAL; + + /* Refuse prefixes that don't have a prefix set */ + if (IN6_IS_ADDR_UNSPECIFIED(&p->opt.in6_addr)) + return -ENOEXEC; + + LIST_FOREACH(prefix, cur, ra->prefixes) { + + r = in_addr_prefix_intersect(AF_INET6, + (union in_addr_union*) &cur->opt.in6_addr, + cur->opt.prefixlen, + (union in_addr_union*) &p->opt.in6_addr, + p->opt.prefixlen); + if (r > 0) { + _cleanup_free_ char *addr_cur = NULL; + + (void) in_addr_to_string(AF_INET6, + (union in_addr_union*) &p->opt.in6_addr, + &addr_p); + + if (dynamic && cur->opt.prefixlen == p->opt.prefixlen) + goto update; + + (void) in_addr_to_string(AF_INET6, + (union in_addr_union*) &cur->opt.in6_addr, + &addr_cur); + log_radv("IPv6 prefix %s/%u already configured, ignoring %s/%u", + addr_cur, cur->opt.prefixlen, + addr_p, p->opt.prefixlen); + + return -EEXIST; + } + } + + p = sd_radv_prefix_ref(p); + + LIST_APPEND(prefix, ra->prefixes, p); + + ra->n_prefixes++; + + (void) in_addr_to_string(AF_INET6, (union in_addr_union*) &p->opt.in6_addr, &addr_p); + + if (!dynamic) { + log_radv("Added prefix %s/%d", addr_p, p->opt.prefixlen); + return 0; + } + + cur = p; + + update: + r = sd_event_now(ra->event, clock_boottime_or_monotonic(), &time_now); + if (r < 0) + return r; + + valid = be32toh(p->opt.valid_lifetime) * USEC_PER_SEC; + valid_until = usec_add(valid, time_now); + if (valid_until == USEC_INFINITY) + return -EOVERFLOW; + + preferred = be32toh(p->opt.preferred_lifetime) * USEC_PER_SEC; + preferred_until = usec_add(preferred, time_now); + if (preferred_until == USEC_INFINITY) + return -EOVERFLOW; + + cur->valid_until = valid_until; + cur->preferred_until = preferred_until; + + log_radv("%s prefix %s/%u preferred %s valid %s", + cur? "Updated": "Added", + addr_p, p->opt.prefixlen, + format_timespan(time_string_preferred, FORMAT_TIMESPAN_MAX, + preferred, USEC_PER_SEC), + format_timespan(time_string_valid, FORMAT_TIMESPAN_MAX, + valid, USEC_PER_SEC)); + + return 0; +} + +_public_ sd_radv_prefix *sd_radv_remove_prefix(sd_radv *ra, + const struct in6_addr *prefix, + unsigned char prefixlen) { + sd_radv_prefix *cur, *next; + + assert_return(ra, NULL); + assert_return(prefix, NULL); + + LIST_FOREACH_SAFE(prefix, cur, next, ra->prefixes) { + if (prefixlen != cur->opt.prefixlen) + continue; + + if (!in_addr_equal(AF_INET6, + (union in_addr_union *)prefix, + (union in_addr_union *)&cur->opt.in6_addr)) + continue; + + LIST_REMOVE(prefix, ra->prefixes, cur); + ra->n_prefixes--; + + break; + } + + return cur; +} + +_public_ int sd_radv_set_rdnss(sd_radv *ra, uint32_t lifetime, + const struct in6_addr *dns, size_t n_dns) { + _cleanup_free_ struct sd_radv_opt_dns *opt_rdnss = NULL; + size_t len; + + assert_return(ra, -EINVAL); + assert_return(n_dns < 128, -EINVAL); + + if (!dns || n_dns == 0) { + ra->rdnss = mfree(ra->rdnss); + ra->n_rdnss = 0; + + return 0; + } + + len = sizeof(struct sd_radv_opt_dns) + sizeof(struct in6_addr) * n_dns; + + opt_rdnss = malloc0(len); + if (!opt_rdnss) + return -ENOMEM; + + opt_rdnss->type = SD_RADV_OPT_RDNSS; + opt_rdnss->length = len / 8; + opt_rdnss->lifetime = htobe32(lifetime); + + memcpy(opt_rdnss + 1, dns, n_dns * sizeof(struct in6_addr)); + + free_and_replace(ra->rdnss, opt_rdnss); + + ra->n_rdnss = n_dns; + + return 0; +} + +_public_ int sd_radv_set_dnssl(sd_radv *ra, uint32_t lifetime, + char **search_list) { + _cleanup_free_ struct sd_radv_opt_dns *opt_dnssl = NULL; + size_t len = 0; + char **s; + uint8_t *p; + + assert_return(ra, -EINVAL); + + if (strv_isempty(search_list)) { + ra->dnssl = mfree(ra->dnssl); + return 0; + } + + STRV_FOREACH(s, search_list) + len += strlen(*s) + 2; + + len = (sizeof(struct sd_radv_opt_dns) + len + 7) & ~0x7; + + opt_dnssl = malloc0(len); + if (!opt_dnssl) + return -ENOMEM; + + opt_dnssl->type = SD_RADV_OPT_DNSSL; + opt_dnssl->length = len / 8; + opt_dnssl->lifetime = htobe32(lifetime); + + p = (uint8_t *)(opt_dnssl + 1); + len -= sizeof(struct sd_radv_opt_dns); + + STRV_FOREACH(s, search_list) { + int r; + + r = dns_name_to_wire_format(*s, p, len, false); + if (r < 0) + return r; + + if (len < (size_t)r) + return -ENOBUFS; + + p += r; + len -= r; + } + + free_and_replace(ra->dnssl, opt_dnssl); + + return 0; +} + +_public_ int sd_radv_prefix_new(sd_radv_prefix **ret) { + sd_radv_prefix *p; + + assert_return(ret, -EINVAL); + + p = new(sd_radv_prefix, 1); + if (!p) + return -ENOMEM; + + *p = (sd_radv_prefix) { + .n_ref = 1, + + .opt.type = ND_OPT_PREFIX_INFORMATION, + .opt.length = (sizeof(p->opt) - 1)/8 + 1, + .opt.prefixlen = 64, + + /* RFC 4861, Section 6.2.1 */ + .opt.flags = ND_OPT_PI_FLAG_ONLINK|ND_OPT_PI_FLAG_AUTO, + + .opt.preferred_lifetime = htobe32(604800), + .opt.valid_lifetime = htobe32(2592000), + }; + + *ret = p; + return 0; +} + +DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv_prefix, sd_radv_prefix, mfree); + +_public_ int sd_radv_prefix_set_prefix(sd_radv_prefix *p, const struct in6_addr *in6_addr, + unsigned char prefixlen) { + assert_return(p, -EINVAL); + assert_return(in6_addr, -EINVAL); + + if (prefixlen < 3 || prefixlen > 128) + return -EINVAL; + + if (prefixlen > 64) + /* unusual but allowed, log it */ + log_radv("Unusual prefix length %d greater than 64", prefixlen); + + p->opt.in6_addr = *in6_addr; + p->opt.prefixlen = prefixlen; + + return 0; +} + +_public_ int sd_radv_prefix_set_onlink(sd_radv_prefix *p, int onlink) { + assert_return(p, -EINVAL); + + SET_FLAG(p->opt.flags, ND_OPT_PI_FLAG_ONLINK, onlink); + + return 0; +} + +_public_ int sd_radv_prefix_set_address_autoconfiguration(sd_radv_prefix *p, + int address_autoconfiguration) { + assert_return(p, -EINVAL); + + SET_FLAG(p->opt.flags, ND_OPT_PI_FLAG_AUTO, address_autoconfiguration); + + return 0; +} + +_public_ int sd_radv_prefix_set_valid_lifetime(sd_radv_prefix *p, + uint32_t valid_lifetime) { + assert_return(p, -EINVAL); + + p->opt.valid_lifetime = htobe32(valid_lifetime); + + return 0; +} + +_public_ int sd_radv_prefix_set_preferred_lifetime(sd_radv_prefix *p, + uint32_t preferred_lifetime) { + assert_return(p, -EINVAL); + + p->opt.preferred_lifetime = htobe32(preferred_lifetime); + + return 0; +} |