diff options
Diffstat (limited to 'src/libsystemd-network/ndisc-router.c')
| -rw-r--r-- | src/libsystemd-network/ndisc-router.c | 779 |
1 files changed, 779 insertions, 0 deletions
diff --git a/src/libsystemd-network/ndisc-router.c b/src/libsystemd-network/ndisc-router.c new file mode 100644 index 0000000000..d9950b638c --- /dev/null +++ b/src/libsystemd-network/ndisc-router.c @@ -0,0 +1,779 @@ +/*** + 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 "sd-ndisc.h" + +#include "alloc-util.h" +#include "dns-domain.h" +#include "hostname-util.h" +#include "missing.h" +#include "ndisc-internal.h" +#include "ndisc-router.h" +#include "strv.h" + +_public_ sd_ndisc_router* sd_ndisc_router_ref(sd_ndisc_router *rt) { + if (!rt) + return NULL; + + assert(rt->n_ref > 0); + rt->n_ref++; + + return rt; +} + +_public_ sd_ndisc_router* sd_ndisc_router_unref(sd_ndisc_router *rt) { + if (!rt) + return NULL; + + assert(rt->n_ref > 0); + rt->n_ref--; + + if (rt->n_ref > 0) + return NULL; + + free(rt); + return NULL; +} + +sd_ndisc_router *ndisc_router_new(size_t raw_size) { + sd_ndisc_router *rt; + + rt = malloc0(ALIGN(sizeof(sd_ndisc_router)) + raw_size); + if (!rt) + return NULL; + + rt->raw_size = raw_size; + rt->n_ref = 1; + + return rt; +} + +_public_ int sd_ndisc_router_from_raw(sd_ndisc_router **ret, const void *raw, size_t raw_size) { + _cleanup_(sd_ndisc_router_unrefp) sd_ndisc_router *rt = NULL; + int r; + + assert_return(ret, -EINVAL); + assert_return(raw || raw_size <= 0, -EINVAL); + + rt = ndisc_router_new(raw_size); + if (!rt) + return -ENOMEM; + + memcpy(NDISC_ROUTER_RAW(rt), raw, raw_size); + r = ndisc_router_parse(rt); + if (r < 0) + return r; + + *ret = rt; + rt = NULL; + + return r; +} + +_public_ int sd_ndisc_router_get_address(sd_ndisc_router *rt, struct in6_addr *ret_addr) { + assert_return(rt, -EINVAL); + assert_return(ret_addr, -EINVAL); + + if (in6_addr_is_null(&rt->address)) + return -ENODATA; + + *ret_addr = rt->address; + return 0; +} + +_public_ int sd_ndisc_router_get_timestamp(sd_ndisc_router *rt, clockid_t clock, uint64_t *ret) { + assert_return(rt, -EINVAL); + assert_return(TRIPLE_TIMESTAMP_HAS_CLOCK(clock), -EOPNOTSUPP); + assert_return(clock_supported(clock), -EOPNOTSUPP); + assert_return(ret, -EINVAL); + + if (!triple_timestamp_is_set(&rt->timestamp)) + return -ENODATA; + + *ret = triple_timestamp_by_clock(&rt->timestamp, clock); + return 0; +} + +_public_ int sd_ndisc_router_get_raw(sd_ndisc_router *rt, const void **ret, size_t *size) { + assert_return(rt, -EINVAL); + assert_return(ret, -EINVAL); + assert_return(size, -EINVAL); + + *ret = NDISC_ROUTER_RAW(rt); + *size = rt->raw_size; + + return 0; +} + +int ndisc_router_parse(sd_ndisc_router *rt) { + struct nd_router_advert *a; + const uint8_t *p; + bool has_mtu = false, has_flag_extension = false; + size_t left; + + assert(rt); + + if (rt->raw_size < sizeof(struct nd_router_advert)) { + log_ndisc("Too small to be a router advertisement, ignoring."); + return -EBADMSG; + } + + /* Router advertisement packets are neatly aligned to 64bit boundaries, hence we can access them directly */ + a = NDISC_ROUTER_RAW(rt); + + if (a->nd_ra_type != ND_ROUTER_ADVERT) { + log_ndisc("Received ND packet that is not a router advertisement, ignoring."); + return -EBADMSG; + } + + if (a->nd_ra_code != 0) { + log_ndisc("Received ND packet with wrong RA code, ignoring."); + return -EBADMSG; + } + + rt->hop_limit = a->nd_ra_curhoplimit; + rt->flags = a->nd_ra_flags_reserved; /* the first 8bit */ + rt->lifetime = be16toh(a->nd_ra_router_lifetime); + + rt->preference = (rt->flags >> 3) & 3; + if (!IN_SET(rt->preference, SD_NDISC_PREFERENCE_LOW, SD_NDISC_PREFERENCE_HIGH)) + rt->preference = SD_NDISC_PREFERENCE_MEDIUM; + + p = (const uint8_t*) NDISC_ROUTER_RAW(rt) + sizeof(struct nd_router_advert); + left = rt->raw_size - sizeof(struct nd_router_advert); + + for (;;) { + uint8_t type; + size_t length; + + if (left == 0) + break; + + if (left < 2) { + log_ndisc("Option lacks header, ignoring datagram."); + return -EBADMSG; + } + + type = p[0]; + length = p[1] * 8; + + if (length == 0) { + log_ndisc("Zero-length option, ignoring datagram."); + return -EBADMSG; + } + if (left < length) { + log_ndisc("Option truncated, ignoring datagram."); + return -EBADMSG; + } + + switch (type) { + + case SD_NDISC_OPTION_PREFIX_INFORMATION: + + if (length != 4*8) { + log_ndisc("Prefix option of invalid size, ignoring datagram."); + return -EBADMSG; + } + + if (p[2] > 128) { + log_ndisc("Bad prefix length, ignoring datagram."); + return -EBADMSG; + } + + break; + + case SD_NDISC_OPTION_MTU: { + uint32_t m; + + if (has_mtu) { + log_ndisc("MTU option specified twice, ignoring."); + continue; + } + + if (length != 8) { + log_ndisc("MTU option of invalid size, ignoring datagram."); + return -EBADMSG; + } + + m = be32toh(*(uint32_t*) (p + 4)); + if (m >= IPV6_MIN_MTU) /* ignore invalidly small MTUs */ + rt->mtu = m; + + has_mtu = true; + break; + } + + case SD_NDISC_OPTION_ROUTE_INFORMATION: + if (length < 1*8 || length > 3*8) { + log_ndisc("Route information option of invalid size, ignoring datagram."); + return -EBADMSG; + } + + if (p[2] > 128) { + log_ndisc("Bad route prefix length, ignoring datagram."); + return -EBADMSG; + } + + break; + + case SD_NDISC_OPTION_RDNSS: + if (length < 3*8 || (length % (2*8)) != 1*8) { + log_ndisc("RDNSS option has invalid size."); + return -EBADMSG; + } + + break; + + case SD_NDISC_OPTION_FLAGS_EXTENSION: + + if (has_flag_extension) { + log_ndisc("Flags extension option specified twice, ignoring."); + continue; + } + + if (length < 1*8) { + log_ndisc("Flags extension option has invalid size."); + return -EBADMSG; + } + + /* Add in the additional flags bits */ + rt->flags |= + ((uint64_t) p[2] << 8) | + ((uint64_t) p[3] << 16) | + ((uint64_t) p[4] << 24) | + ((uint64_t) p[5] << 32) | + ((uint64_t) p[6] << 40) | + ((uint64_t) p[7] << 48); + + has_flag_extension = true; + break; + + case SD_NDISC_OPTION_DNSSL: + if (length < 2*8) { + log_ndisc("DNSSL option has invalid size."); + return -EBADMSG; + } + + break; + } + + p += length, left -= length; + } + + rt->rindex = sizeof(struct nd_router_advert); + return 0; +} + +_public_ int sd_ndisc_router_get_hop_limit(sd_ndisc_router *rt, uint8_t *ret) { + assert_return(rt, -EINVAL); + assert_return(ret, -EINVAL); + + *ret = rt->hop_limit; + return 0; +} + +_public_ int sd_ndisc_router_get_flags(sd_ndisc_router *rt, uint64_t *ret_flags) { + assert_return(rt, -EINVAL); + assert_return(ret_flags, -EINVAL); + + *ret_flags = rt->flags; + return 0; +} + +_public_ int sd_ndisc_router_get_lifetime(sd_ndisc_router *rt, uint16_t *ret_lifetime) { + assert_return(rt, -EINVAL); + assert_return(ret_lifetime, -EINVAL); + + *ret_lifetime = rt->lifetime; + return 0; +} + +_public_ int sd_ndisc_router_get_preference(sd_ndisc_router *rt, unsigned *ret) { + assert_return(rt, -EINVAL); + assert_return(ret, -EINVAL); + + *ret = rt->preference; + return 0; +} + +_public_ int sd_ndisc_router_get_mtu(sd_ndisc_router *rt, uint32_t *ret) { + assert_return(rt, -EINVAL); + assert_return(ret, -EINVAL); + + if (rt->mtu <= 0) + return -ENODATA; + + *ret = rt->mtu; + return 0; +} + +_public_ int sd_ndisc_router_option_rewind(sd_ndisc_router *rt) { + assert_return(rt, -EINVAL); + + assert(rt->raw_size >= sizeof(struct nd_router_advert)); + rt->rindex = sizeof(struct nd_router_advert); + + return rt->rindex < rt->raw_size; +} + +_public_ int sd_ndisc_router_option_next(sd_ndisc_router *rt) { + size_t length; + + assert_return(rt, -EINVAL); + + if (rt->rindex == rt->raw_size) /* EOF */ + return -ESPIPE; + + if (rt->rindex + 2 > rt->raw_size) /* Truncated message */ + return -EBADMSG; + + length = NDISC_ROUTER_OPTION_LENGTH(rt); + if (rt->rindex + length > rt->raw_size) + return -EBADMSG; + + rt->rindex += length; + return rt->rindex < rt->raw_size; +} + +_public_ int sd_ndisc_router_option_get_type(sd_ndisc_router *rt, uint8_t *ret) { + assert_return(rt, -EINVAL); + assert_return(ret, -EINVAL); + + if (rt->rindex == rt->raw_size) /* EOF */ + return -ESPIPE; + + if (rt->rindex + 2 > rt->raw_size) /* Truncated message */ + return -EBADMSG; + + *ret = NDISC_ROUTER_OPTION_TYPE(rt); + return 0; +} + +_public_ int sd_ndisc_router_option_is_type(sd_ndisc_router *rt, uint8_t type) { + uint8_t k; + int r; + + assert_return(rt, -EINVAL); + + r = sd_ndisc_router_option_get_type(rt, &k); + if (r < 0) + return r; + + return type == k; +} + +_public_ int sd_ndisc_router_option_get_raw(sd_ndisc_router *rt, const void **ret, size_t *size) { + size_t length; + + assert_return(rt, -EINVAL); + assert_return(ret, -EINVAL); + assert_return(size, -EINVAL); + + /* Note that this returns the full option, including the option header */ + + if (rt->rindex + 2 > rt->raw_size) + return -EBADMSG; + + length = NDISC_ROUTER_OPTION_LENGTH(rt); + if (rt->rindex + length > rt->raw_size) + return -EBADMSG; + + *ret = (uint8_t*) NDISC_ROUTER_RAW(rt) + rt->rindex; + *size = length; + + return 0; +} + +static int get_prefix_info(sd_ndisc_router *rt, struct nd_opt_prefix_info **ret) { + struct nd_opt_prefix_info *ri; + size_t length; + int r; + + assert(rt); + assert(ret); + + r = sd_ndisc_router_option_is_type(rt, SD_NDISC_OPTION_PREFIX_INFORMATION); + if (r < 0) + return r; + if (r == 0) + return -EMEDIUMTYPE; + + length = NDISC_ROUTER_OPTION_LENGTH(rt); + if (length != sizeof(struct nd_opt_prefix_info)) + return -EBADMSG; + + ri = (struct nd_opt_prefix_info*) ((uint8_t*) NDISC_ROUTER_RAW(rt) + rt->rindex); + if (ri->nd_opt_pi_prefix_len > 128) + return -EBADMSG; + + *ret = ri; + return 0; +} + +_public_ int sd_ndisc_router_prefix_get_valid_lifetime(sd_ndisc_router *rt, uint32_t *ret) { + struct nd_opt_prefix_info *ri; + int r; + + assert_return(rt, -EINVAL); + assert_return(ret, -EINVAL); + + r = get_prefix_info(rt, &ri); + if (r < 0) + return r; + + *ret = be32toh(ri->nd_opt_pi_valid_time); + return 0; +} + +_public_ int sd_ndisc_router_prefix_get_preferred_lifetime(sd_ndisc_router *rt, uint32_t *ret) { + struct nd_opt_prefix_info *pi; + int r; + + assert_return(rt, -EINVAL); + assert_return(ret, -EINVAL); + + r = get_prefix_info(rt, &pi); + if (r < 0) + return r; + + *ret = be32toh(pi->nd_opt_pi_preferred_time); + return 0; +} + +_public_ int sd_ndisc_router_prefix_get_flags(sd_ndisc_router *rt, uint8_t *ret) { + struct nd_opt_prefix_info *pi; + int r; + + assert_return(rt, -EINVAL); + assert_return(ret, -EINVAL); + + r = get_prefix_info(rt, &pi); + if (r < 0) + return r; + + *ret = pi->nd_opt_pi_flags_reserved; + return 0; +} + +_public_ int sd_ndisc_router_prefix_get_address(sd_ndisc_router *rt, struct in6_addr *ret_addr) { + struct nd_opt_prefix_info *pi; + int r; + + assert_return(rt, -EINVAL); + assert_return(ret_addr, -EINVAL); + + r = get_prefix_info(rt, &pi); + if (r < 0) + return r; + + *ret_addr = pi->nd_opt_pi_prefix; + return 0; +} + +_public_ int sd_ndisc_router_prefix_get_prefixlen(sd_ndisc_router *rt, unsigned *ret) { + struct nd_opt_prefix_info *pi; + int r; + + assert_return(rt, -EINVAL); + assert_return(ret, -EINVAL); + + r = get_prefix_info(rt, &pi); + if (r < 0) + return r; + + if (pi->nd_opt_pi_prefix_len > 128) + return -EBADMSG; + + *ret = pi->nd_opt_pi_prefix_len; + return 0; +} + +static int get_route_info(sd_ndisc_router *rt, uint8_t **ret) { + uint8_t *ri; + size_t length; + int r; + + assert(rt); + assert(ret); + + r = sd_ndisc_router_option_is_type(rt, SD_NDISC_OPTION_ROUTE_INFORMATION); + if (r < 0) + return r; + if (r == 0) + return -EMEDIUMTYPE; + + length = NDISC_ROUTER_OPTION_LENGTH(rt); + if (length < 1*8 || length > 3*8) + return -EBADMSG; + + ri = (uint8_t*) NDISC_ROUTER_RAW(rt) + rt->rindex; + + if (ri[2] > 128) + return -EBADMSG; + + *ret = ri; + return 0; +} + +_public_ int sd_ndisc_router_route_get_lifetime(sd_ndisc_router *rt, uint32_t *ret) { + uint8_t *ri; + int r; + + assert_return(rt, -EINVAL); + assert_return(ret, -EINVAL); + + r = get_route_info(rt, &ri); + if (r < 0) + return r; + + *ret = be32toh(*(uint32_t*) (ri + 4)); + return 0; +} + +_public_ int sd_ndisc_router_route_get_address(sd_ndisc_router *rt, struct in6_addr *ret_addr) { + uint8_t *ri; + int r; + + assert_return(rt, -EINVAL); + assert_return(ret_addr, -EINVAL); + + r = get_route_info(rt, &ri); + if (r < 0) + return r; + + zero(*ret_addr); + memcpy(ret_addr, ri + 8, NDISC_ROUTER_OPTION_LENGTH(rt) - 8); + + return 0; +} + +_public_ int sd_ndisc_router_route_get_prefixlen(sd_ndisc_router *rt, unsigned *ret) { + uint8_t *ri; + int r; + + assert_return(rt, -EINVAL); + assert_return(ret, -EINVAL); + + r = get_route_info(rt, &ri); + if (r < 0) + return r; + + *ret = ri[2]; + return 0; +} + +_public_ int sd_ndisc_router_route_get_preference(sd_ndisc_router *rt, unsigned *ret) { + uint8_t *ri; + int r; + + assert_return(rt, -EINVAL); + assert_return(ret, -EINVAL); + + r = get_route_info(rt, &ri); + if (r < 0) + return r; + + *ret = (ri[3] >> 3) & 3; + if (!IN_SET(*ret, SD_NDISC_PREFERENCE_LOW, SD_NDISC_PREFERENCE_HIGH)) + *ret = SD_NDISC_PREFERENCE_MEDIUM; + + return 0; +} + +static int get_rdnss_info(sd_ndisc_router *rt, uint8_t **ret) { + size_t length; + int r; + + assert(rt); + assert(ret); + + r = sd_ndisc_router_option_is_type(rt, SD_NDISC_OPTION_RDNSS); + if (r < 0) + return r; + if (r == 0) + return -EMEDIUMTYPE; + + length = NDISC_ROUTER_OPTION_LENGTH(rt); + if (length < 3*8 || (length % (2*8)) != 1*8) + return -EBADMSG; + + *ret = (uint8_t*) NDISC_ROUTER_RAW(rt) + rt->rindex; + return 0; +} + +_public_ int sd_ndisc_router_rdnss_get_addresses(sd_ndisc_router *rt, const struct in6_addr **ret) { + uint8_t *ri; + int r; + + assert_return(rt, -EINVAL); + assert_return(ret, -EINVAL); + + r = get_rdnss_info(rt, &ri); + if (r < 0) + return r; + + *ret = (const struct in6_addr*) (ri + 8); + return (NDISC_ROUTER_OPTION_LENGTH(rt) - 8) / 16; +} + +_public_ int sd_ndisc_router_rdnss_get_lifetime(sd_ndisc_router *rt, uint32_t *ret) { + uint8_t *ri; + int r; + + assert_return(rt, -EINVAL); + assert_return(ret, -EINVAL); + + r = get_rdnss_info(rt, &ri); + if (r < 0) + return r; + + *ret = be32toh(*(uint32_t*) (ri + 4)); + return 0; +} + +static int get_dnssl_info(sd_ndisc_router *rt, uint8_t **ret) { + size_t length; + int r; + + assert(rt); + assert(ret); + + r = sd_ndisc_router_option_is_type(rt, SD_NDISC_OPTION_DNSSL); + if (r < 0) + return r; + if (r == 0) + return -EMEDIUMTYPE; + + length = NDISC_ROUTER_OPTION_LENGTH(rt); + if (length < 2*8) + return -EBADMSG; + + *ret = (uint8_t*) NDISC_ROUTER_RAW(rt) + rt->rindex; + return 0; +} + +_public_ int sd_ndisc_router_dnssl_get_domains(sd_ndisc_router *rt, char ***ret) { + _cleanup_strv_free_ char **l = NULL; + _cleanup_free_ char *e = NULL; + size_t allocated = 0, n = 0, left; + uint8_t *ri, *p; + bool first = true; + int r; + unsigned k = 0; + + assert_return(rt, -EINVAL); + assert_return(ret, -EINVAL); + + r = get_dnssl_info(rt, &ri); + if (r < 0) + return r; + + p = ri + 8; + left = NDISC_ROUTER_OPTION_LENGTH(rt) - 8; + + for (;;) { + if (left == 0) { + + if (n > 0) /* Not properly NUL terminated */ + return -EBADMSG; + + break; + } + + if (*p == 0) { + /* Found NUL termination */ + + if (n > 0) { + _cleanup_free_ char *normalized = NULL; + + e[n] = 0; + r = dns_name_normalize(e, &normalized); + if (r < 0) + return r; + + /* Ignore the root domain name or "localhost" and friends */ + if (!is_localhost(normalized) && + !dns_name_is_root(normalized)) { + + if (strv_push(&l, normalized) < 0) + return -ENOMEM; + + normalized = NULL; + k++; + } + } + + n = 0; + first = true; + p++, left--; + continue; + } + + /* Check for compression (which is not allowed) */ + if (*p > 63) + return -EBADMSG; + + if (1U + *p + 1U > left) + return -EBADMSG; + + if (!GREEDY_REALLOC(e, allocated, n + !first + DNS_LABEL_ESCAPED_MAX + 1U)) + return -ENOMEM; + + if (first) + first = false; + else + e[n++] = '.'; + + r = dns_label_escape((char*) p+1, *p, e + n, DNS_LABEL_ESCAPED_MAX); + if (r < 0) + return r; + + n += r; + + left -= 1 + *p; + p += 1 + *p; + } + + if (strv_isempty(l)) { + *ret = NULL; + return 0; + } + + *ret = l; + l = NULL; + + return k; +} + +_public_ int sd_ndisc_router_dnssl_get_lifetime(sd_ndisc_router *rt, uint32_t *ret_sec) { + uint8_t *ri; + int r; + + assert_return(rt, -EINVAL); + assert_return(ret_sec, -EINVAL); + + r = get_dnssl_info(rt, &ri); + if (r < 0) + return r; + + *ret_sec = be32toh(*(uint32_t*) (ri + 4)); + return 0; +} |