diff options
Diffstat (limited to 'src/libsystemd-network/ndisc-option.c')
| -rw-r--r-- | src/libsystemd-network/ndisc-option.c | 1502 |
1 files changed, 1502 insertions, 0 deletions
diff --git a/src/libsystemd-network/ndisc-option.c b/src/libsystemd-network/ndisc-option.c new file mode 100644 index 0000000..901a3b3 --- /dev/null +++ b/src/libsystemd-network/ndisc-option.c @@ -0,0 +1,1502 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ + +#include <netinet/icmp6.h> + +#include "dns-domain.h" +#include "ether-addr-util.h" +#include "hostname-util.h" +#include "icmp6-util.h" +#include "in-addr-util.h" +#include "iovec-util.h" +#include "missing_network.h" +#include "ndisc-option.h" +#include "network-common.h" +#include "strv.h" +#include "unaligned.h" + +/* RFC does not say anything about the maximum number of options, but let's limit the number of options for + * safety. Typically, the number of options in an ICMPv6 message should be only a few. */ +#define MAX_OPTIONS 128 + +int ndisc_option_parse( + ICMP6Packet *p, + size_t offset, + uint8_t *ret_type, + size_t *ret_len, + const uint8_t **ret_opt) { + + assert(p); + + if (offset == p->raw_size) + return -ESPIPE; /* end of the packet */ + + if (offset > p->raw_size) + return -EBADMSG; + + if (p->raw_size - offset < sizeof(struct nd_opt_hdr)) + return -EBADMSG; + + assert_cc(alignof(struct nd_opt_hdr) == 1); + const struct nd_opt_hdr *hdr = (const struct nd_opt_hdr*) (p->raw_packet + offset); + if (hdr->nd_opt_len == 0) + return -EBADMSG; + + size_t len = hdr->nd_opt_len * 8; + if (p->raw_size - offset < len) + return -EBADMSG; + + if (ret_type) + *ret_type = hdr->nd_opt_type; + if (ret_len) + *ret_len = len; + if (ret_opt) + *ret_opt = p->raw_packet + offset; + + return 0; +} + +static sd_ndisc_option* ndisc_option_new(uint8_t type, size_t offset) { + sd_ndisc_option *p = new0(sd_ndisc_option, 1); /* use new0() here to make the fuzzers silent. */ + if (!p) + return NULL; + + /* As the same reason in the above, do not use the structured initializer here. */ + p->type = type; + p->offset = offset; + + return p; +} + +static void ndisc_raw_done(sd_ndisc_raw *raw) { + if (!raw) + return; + + free(raw->bytes); +} + +static void ndisc_rdnss_done(sd_ndisc_rdnss *rdnss) { + if (!rdnss) + return; + + free(rdnss->addresses); +} + +static void ndisc_dnssl_done(sd_ndisc_dnssl *dnssl) { + if (!dnssl) + return; + + strv_free(dnssl->domains); +} + +sd_ndisc_option* ndisc_option_free(sd_ndisc_option *option) { + if (!option) + return NULL; + + switch (option->type) { + case 0: + ndisc_raw_done(&option->raw); + break; + + case SD_NDISC_OPTION_RDNSS: + ndisc_rdnss_done(&option->rdnss); + break; + + case SD_NDISC_OPTION_DNSSL: + ndisc_dnssl_done(&option->dnssl); + break; + + case SD_NDISC_OPTION_CAPTIVE_PORTAL: + free(option->captive_portal); + break; + } + + return mfree(option); +} + +static int ndisc_option_compare_func(const sd_ndisc_option *x, const sd_ndisc_option *y) { + int r; + + assert(x); + assert(y); + + r = CMP(x->type, y->type); + if (r != 0) + return r; + + switch (x->type) { + case 0: + return memcmp_nn(x->raw.bytes, x->raw.length, y->raw.bytes, y->raw.length); + + case SD_NDISC_OPTION_SOURCE_LL_ADDRESS: + case SD_NDISC_OPTION_TARGET_LL_ADDRESS: + case SD_NDISC_OPTION_REDIRECTED_HEADER: + case SD_NDISC_OPTION_MTU: + case SD_NDISC_OPTION_HOME_AGENT: + case SD_NDISC_OPTION_FLAGS_EXTENSION: + case SD_NDISC_OPTION_CAPTIVE_PORTAL: + /* These options cannot be specified multiple times. */ + return 0; + + case SD_NDISC_OPTION_PREFIX_INFORMATION: + /* Should not specify the same prefix multiple times. */ + r = CMP(x->prefix.prefixlen, y->prefix.prefixlen); + if (r != 0) + return r; + + return memcmp(&x->prefix.address, &y->prefix.address, sizeof(struct in6_addr)); + + case SD_NDISC_OPTION_ROUTE_INFORMATION: + r = CMP(x->route.prefixlen, y->route.prefixlen); + if (r != 0) + return r; + + return memcmp(&x->route.address, &y->route.address, sizeof(struct in6_addr)); + + case SD_NDISC_OPTION_PREF64: + r = CMP(x->prefix64.prefixlen, y->prefix64.prefixlen); + if (r != 0) + return r; + + return memcmp(&x->prefix64.prefix, &y->prefix64.prefix, sizeof(struct in6_addr)); + + default: + /* DNSSL, RDNSS, and other unsupported options can be specified multiple times. */ + return trivial_compare_func(x, y); + } +} + +static void ndisc_option_hash_func(const sd_ndisc_option *option, struct siphash *state) { + assert(option); + assert(state); + + siphash24_compress_typesafe(option->type, state); + + switch (option->type) { + case 0: + siphash24_compress(option->raw.bytes, option->raw.length, state); + break; + + case SD_NDISC_OPTION_SOURCE_LL_ADDRESS: + case SD_NDISC_OPTION_TARGET_LL_ADDRESS: + case SD_NDISC_OPTION_REDIRECTED_HEADER: + case SD_NDISC_OPTION_MTU: + case SD_NDISC_OPTION_HOME_AGENT: + case SD_NDISC_OPTION_FLAGS_EXTENSION: + case SD_NDISC_OPTION_CAPTIVE_PORTAL: + break; + + case SD_NDISC_OPTION_PREFIX_INFORMATION: + siphash24_compress_typesafe(option->prefix.prefixlen, state); + siphash24_compress_typesafe(option->prefix.address, state); + break; + + case SD_NDISC_OPTION_ROUTE_INFORMATION: + siphash24_compress_typesafe(option->route.prefixlen, state); + siphash24_compress_typesafe(option->route.address, state); + break; + + case SD_NDISC_OPTION_PREF64: + siphash24_compress_typesafe(option->prefix64.prefixlen, state); + siphash24_compress_typesafe(option->prefix64.prefix, state); + break; + + default: + trivial_hash_func(option, state); + } +} + +DEFINE_PRIVATE_HASH_OPS_WITH_KEY_DESTRUCTOR( + ndisc_option_hash_ops, + sd_ndisc_option, + ndisc_option_hash_func, + ndisc_option_compare_func, + ndisc_option_free); + +static int ndisc_option_consume(Set **options, sd_ndisc_option *p) { + assert(options); + assert(p); + + if (set_size(*options) >= MAX_OPTIONS) { + ndisc_option_free(p); + return -ETOOMANYREFS; /* recognizable error code */ + } + + return set_ensure_consume(options, &ndisc_option_hash_ops, p); +} + +int ndisc_option_set_raw(Set **options, size_t length, const uint8_t *bytes) { + _cleanup_free_ uint8_t *copy = NULL; + + assert(options); + assert(bytes); + + if (length == 0) + return -EINVAL; + + copy = newdup(uint8_t, bytes, length); + if (!copy) + return -ENOMEM; + + sd_ndisc_option *p = ndisc_option_new(/* type = */ 0, /* offset = */ 0); + if (!p) + return -ENOMEM; + + p->raw = (sd_ndisc_raw) { + .bytes = TAKE_PTR(copy), + .length = length, + }; + + return ndisc_option_consume(options, p); +} + +static int ndisc_option_build_raw(const sd_ndisc_option *option, uint8_t **ret) { + assert(option); + assert(option->type == 0); + assert(ret); + + _cleanup_free_ uint8_t *buf = newdup(uint8_t, option->raw.bytes, option->raw.length); + if (!buf) + return -ENOMEM; + + *ret = TAKE_PTR(buf); + return 0; +} + +int ndisc_option_add_link_layer_address(Set **options, uint8_t type, size_t offset, const struct ether_addr *mac) { + assert(options); + assert(IN_SET(type, SD_NDISC_OPTION_SOURCE_LL_ADDRESS, SD_NDISC_OPTION_TARGET_LL_ADDRESS)); + + if (!mac || ether_addr_is_null(mac)) { + ndisc_option_remove_by_type(*options, type); + return 0; + } + + sd_ndisc_option *p = ndisc_option_get_by_type(*options, type); + if (p) { + /* offset == 0 means that we are now building a packet to be sent, and in that case we allow + * to override the option we previously set. + * offset != 0 means that we are now parsing a received packet, and we refuse to override + * conflicting options. */ + if (offset != 0) + return -EEXIST; + + p->mac = *mac; + return 0; + } + + p = ndisc_option_new(type, offset); + if (!p) + return -ENOMEM; + + p->mac = *mac; + + return set_ensure_consume(options, &ndisc_option_hash_ops, p); +} + +static int ndisc_option_parse_link_layer_address(Set **options, size_t offset, size_t len, const uint8_t *opt) { + assert(options); + assert(opt); + + if (len != sizeof(struct ether_addr) + 2) + return -EBADMSG; + + if (!IN_SET(opt[0], SD_NDISC_OPTION_SOURCE_LL_ADDRESS, SD_NDISC_OPTION_TARGET_LL_ADDRESS)) + return -EBADMSG; + + struct ether_addr mac; + memcpy(&mac, opt + 2, sizeof(struct ether_addr)); + + if (ether_addr_is_null(&mac)) + return -EBADMSG; + + return ndisc_option_add_link_layer_address(options, opt[0], offset, &mac); +} + +static int ndisc_option_build_link_layer_address(const sd_ndisc_option *option, uint8_t **ret) { + assert(option); + assert(IN_SET(option->type, SD_NDISC_OPTION_SOURCE_LL_ADDRESS, SD_NDISC_OPTION_TARGET_LL_ADDRESS)); + assert(ret); + + assert_cc(2 + sizeof(struct ether_addr) == 8); + + _cleanup_free_ uint8_t *buf = new(uint8_t, 2 + sizeof(struct ether_addr)); + if (!buf) + return -ENOMEM; + + buf[0] = option->type; + buf[1] = 1; + memcpy(buf + 2, &option->mac, sizeof(struct ether_addr)); + + *ret = TAKE_PTR(buf); + return 0; +} + +int ndisc_option_add_prefix_internal( + Set **options, + size_t offset, + uint8_t flags, + uint8_t prefixlen, + const struct in6_addr *address, + usec_t valid_lifetime, + usec_t preferred_lifetime, + usec_t valid_until, + usec_t preferred_until) { + + assert(options); + assert(address); + + if (prefixlen > 128) + return -EINVAL; + + struct in6_addr addr = *address; + in6_addr_mask(&addr, prefixlen); + + /* RFC 4861 and 4862 only state that link-local prefix should be ignored. + * But here we also ignore null and multicast addresses. */ + if (in6_addr_is_link_local(&addr) || in6_addr_is_null(&addr) || in6_addr_is_multicast(&addr)) + return -EINVAL; + + if (preferred_lifetime > valid_lifetime) + return -EINVAL; + + if (preferred_until > valid_until) + return -EINVAL; + + sd_ndisc_option *p = ndisc_option_get( + *options, + &(const sd_ndisc_option) { + .type = SD_NDISC_OPTION_PREFIX_INFORMATION, + .prefix.prefixlen = prefixlen, + .prefix.address = addr, + }); + if (p) { + if (offset != 0) + return -EEXIST; + + p->prefix.flags = flags; + p->prefix.valid_lifetime = valid_lifetime; + p->prefix.preferred_lifetime = preferred_lifetime; + p->prefix.valid_until = valid_until; + p->prefix.preferred_until = preferred_until; + return 0; + } + + p = ndisc_option_new(SD_NDISC_OPTION_PREFIX_INFORMATION, offset); + if (!p) + return -ENOMEM; + + p->prefix = (sd_ndisc_prefix) { + .flags = flags, + .prefixlen = prefixlen, + .address = addr, + .valid_lifetime = valid_lifetime, + .preferred_lifetime = preferred_lifetime, + .valid_until = valid_until, + .preferred_until = preferred_until, + }; + + return ndisc_option_consume(options, p); +} + +static int ndisc_option_parse_prefix(Set **options, size_t offset, size_t len, const uint8_t *opt) { + const struct nd_opt_prefix_info *pi = (const struct nd_opt_prefix_info*) ASSERT_PTR(opt); + + assert(options); + + if (len != sizeof(struct nd_opt_prefix_info)) + return -EBADMSG; + + if (pi->nd_opt_pi_type != SD_NDISC_OPTION_PREFIX_INFORMATION) + return -EBADMSG; + + usec_t valid = be32_sec_to_usec(pi->nd_opt_pi_valid_time, /* max_as_infinity = */ true); + usec_t pref = be32_sec_to_usec(pi->nd_opt_pi_preferred_time, /* max_as_infinity = */ true); + + /* We only support 64 bits interface identifier for addrconf. */ + uint8_t flags = pi->nd_opt_pi_flags_reserved; + if (FLAGS_SET(flags, ND_OPT_PI_FLAG_AUTO) && pi->nd_opt_pi_prefix_len != 64) + flags &= ~ND_OPT_PI_FLAG_AUTO; + + return ndisc_option_add_prefix(options, offset, flags, + pi->nd_opt_pi_prefix_len, &pi->nd_opt_pi_prefix, + valid, pref); +} + +static int ndisc_option_build_prefix(const sd_ndisc_option *option, usec_t timestamp, uint8_t **ret) { + assert(option); + assert(option->type == SD_NDISC_OPTION_PREFIX_INFORMATION); + assert(ret); + + assert_cc(sizeof(struct nd_opt_prefix_info) % 8 == 0); + + _cleanup_free_ struct nd_opt_prefix_info *buf = new(struct nd_opt_prefix_info, 1); + if (!buf) + return -ENOMEM; + + usec_t valid = MIN(option->prefix.valid_lifetime, + usec_sub_unsigned(option->prefix.valid_until, timestamp)); + usec_t pref = MIN3(valid, + option->prefix.preferred_lifetime, + usec_sub_unsigned(option->prefix.preferred_until, timestamp)); + + *buf = (struct nd_opt_prefix_info) { + .nd_opt_pi_type = SD_NDISC_OPTION_PREFIX_INFORMATION, + .nd_opt_pi_len = sizeof(struct nd_opt_prefix_info) / 8, + .nd_opt_pi_prefix_len = option->prefix.prefixlen, + .nd_opt_pi_flags_reserved = option->prefix.flags, + .nd_opt_pi_valid_time = usec_to_be32_sec(valid), + .nd_opt_pi_preferred_time = usec_to_be32_sec(pref), + .nd_opt_pi_prefix = option->prefix.address, + }; + + *ret = (uint8_t*) TAKE_PTR(buf); + return 0; +} + +int ndisc_option_add_redirected_header(Set **options, size_t offset, const struct ip6_hdr *hdr) { + assert(options); + + if (!hdr) { + ndisc_option_remove_by_type(*options, SD_NDISC_OPTION_REDIRECTED_HEADER); + return 0; + } + + sd_ndisc_option *p = ndisc_option_get_by_type(*options, SD_NDISC_OPTION_REDIRECTED_HEADER); + if (p) { + if (offset != 0) + return -EEXIST; + + memcpy(&p->hdr, hdr, sizeof(struct ip6_hdr)); + return 0; + } + + p = ndisc_option_new(SD_NDISC_OPTION_REDIRECTED_HEADER, offset); + if (!p) + return -ENOMEM; + + /* For safety, here we copy only IPv6 header. */ + memcpy(&p->hdr, hdr, sizeof(struct ip6_hdr)); + + return ndisc_option_consume(options, p); +} + +static int ndisc_option_parse_redirected_header(Set **options, size_t offset, size_t len, const uint8_t *opt) { + assert(options); + assert(opt); + + if (len < sizeof(struct nd_opt_rd_hdr) + sizeof(struct ip6_hdr)) + return -EBADMSG; + + if (opt[0] != SD_NDISC_OPTION_REDIRECTED_HEADER) + return -EBADMSG; + + return ndisc_option_add_redirected_header(options, offset, (const struct ip6_hdr*) (opt + sizeof(struct nd_opt_rd_hdr))); +} + +static int ndisc_option_build_redirected_header(const sd_ndisc_option *option, uint8_t **ret) { + assert(option); + assert(option->type == SD_NDISC_OPTION_REDIRECTED_HEADER); + assert(ret); + + assert_cc((sizeof(struct nd_opt_rd_hdr) + sizeof(struct ip6_hdr)) % 8 == 0); + + size_t len = DIV_ROUND_UP(sizeof(struct nd_opt_rd_hdr) + sizeof(struct ip6_hdr), 8); + + _cleanup_free_ uint8_t *buf = new(uint8_t, len * 8); + if (!buf) + return -ENOMEM; + + uint8_t *p; + p = mempcpy(buf, + &(const struct nd_opt_rd_hdr) { + .nd_opt_rh_type = SD_NDISC_OPTION_REDIRECTED_HEADER, + .nd_opt_rh_len = len, + }, + sizeof(struct nd_opt_rd_hdr)); + memcpy(p, &option->hdr, sizeof(struct ip6_hdr)); + + *ret = TAKE_PTR(buf); + return 0; +} + +int ndisc_option_add_mtu(Set **options, size_t offset, uint32_t mtu) { + assert(options); + + if (mtu < IPV6_MIN_MTU) + return -EINVAL; + + sd_ndisc_option *p = ndisc_option_get_by_type(*options, SD_NDISC_OPTION_MTU); + if (p) { + if (offset != 0) + return -EEXIST; + + p->mtu = mtu; + return 0; + } + + p = ndisc_option_new(SD_NDISC_OPTION_MTU, offset); + if (!p) + return -ENOMEM; + + p->mtu = mtu; + + return ndisc_option_consume(options, p); +} + +static int ndisc_option_parse_mtu(Set **options, size_t offset, size_t len, const uint8_t *opt) { + const struct nd_opt_mtu *pm = (const struct nd_opt_mtu*) ASSERT_PTR(opt); + + assert(options); + + if (len != sizeof(struct nd_opt_mtu)) + return -EBADMSG; + + if (pm->nd_opt_mtu_type != SD_NDISC_OPTION_MTU) + return -EBADMSG; + + return ndisc_option_add_mtu(options, offset, be32toh(pm->nd_opt_mtu_mtu)); +} + +static int ndisc_option_build_mtu(const sd_ndisc_option *option, uint8_t **ret) { + assert(option); + assert(option->type == SD_NDISC_OPTION_MTU); + assert(ret); + + assert_cc(sizeof(struct nd_opt_mtu) % 8 == 0); + + _cleanup_free_ struct nd_opt_mtu *buf = new(struct nd_opt_mtu, 1); + if (!buf) + return -ENOMEM; + + *buf = (struct nd_opt_mtu) { + .nd_opt_mtu_type = SD_NDISC_OPTION_MTU, + .nd_opt_mtu_len = sizeof(struct nd_opt_mtu) / 8, + .nd_opt_mtu_mtu = htobe32(option->mtu), + }; + + *ret = (uint8_t*) TAKE_PTR(buf); + return 0; +} + +int ndisc_option_add_home_agent_internal( + Set **options, + size_t offset, + uint16_t preference, + usec_t lifetime, + usec_t valid_until) { + + assert(options); + + if (lifetime > UINT16_MAX * USEC_PER_SEC) + return -EINVAL; + + sd_ndisc_option *p = ndisc_option_get_by_type(*options, SD_NDISC_OPTION_HOME_AGENT); + if (p) { + if (offset != 0) + return -EEXIST; + + p->home_agent = (sd_ndisc_home_agent) { + .preference = preference, + .lifetime = lifetime, + .valid_until = valid_until, + }; + return 0; + } + + p = ndisc_option_new(SD_NDISC_OPTION_HOME_AGENT, offset); + if (!p) + return -ENOMEM; + + p->home_agent = (sd_ndisc_home_agent) { + .preference = preference, + .lifetime = lifetime, + .valid_until = valid_until, + }; + + return ndisc_option_consume(options, p); +} + +static int ndisc_option_parse_home_agent(Set **options, size_t offset, size_t len, const uint8_t *opt) { + const struct nd_opt_home_agent_info *p = (const struct nd_opt_home_agent_info*) ASSERT_PTR(opt); + + assert(options); + + if (len != sizeof(struct nd_opt_home_agent_info)) + return -EBADMSG; + + if (p->nd_opt_home_agent_info_type != SD_NDISC_OPTION_HOME_AGENT) + return -EBADMSG; + + return ndisc_option_add_home_agent( + options, offset, + be16toh(p->nd_opt_home_agent_info_preference), + be16_sec_to_usec(p->nd_opt_home_agent_info_lifetime, /* max_as_infinity = */ false)); +} + +static int ndisc_option_build_home_agent(const sd_ndisc_option *option, usec_t timestamp, uint8_t **ret) { + assert(option); + assert(option->type == SD_NDISC_OPTION_HOME_AGENT); + assert(ret); + + assert_cc(sizeof(struct nd_opt_home_agent_info) % 8 == 0); + + usec_t lifetime = MIN(option->home_agent.lifetime, + usec_sub_unsigned(option->home_agent.valid_until, timestamp)); + + _cleanup_free_ struct nd_opt_home_agent_info *buf = new(struct nd_opt_home_agent_info, 1); + if (!buf) + return -ENOMEM; + + *buf = (struct nd_opt_home_agent_info) { + .nd_opt_home_agent_info_type = SD_NDISC_OPTION_HOME_AGENT, + .nd_opt_home_agent_info_len = sizeof(struct nd_opt_home_agent_info) / 8, + .nd_opt_home_agent_info_preference = htobe16(option->home_agent.preference), + .nd_opt_home_agent_info_lifetime = usec_to_be16_sec(lifetime), + }; + + *ret = (uint8_t*) TAKE_PTR(buf); + return 0; +} + +int ndisc_option_add_route_internal( + Set **options, + size_t offset, + uint8_t preference, + uint8_t prefixlen, + const struct in6_addr *prefix, + usec_t lifetime, + usec_t valid_until) { + + assert(options); + assert(prefix); + + if (prefixlen > 128) + return -EINVAL; + + /* RFC 4191 section 2.3 + * Prf (Route Preference) + * 2-bit signed integer. The Route Preference indicates whether to prefer the router associated with + * this prefix over others, when multiple identical prefixes (for different routers) have been + * received. If the Reserved (10) value is received, the Route Information Option MUST be ignored. */ + if (!IN_SET(preference, SD_NDISC_PREFERENCE_LOW, SD_NDISC_PREFERENCE_MEDIUM, SD_NDISC_PREFERENCE_HIGH)) + return -EINVAL; + + struct in6_addr addr = *prefix; + in6_addr_mask(&addr, prefixlen); + + sd_ndisc_option *p = ndisc_option_get( + *options, + &(const sd_ndisc_option) { + .type = SD_NDISC_OPTION_ROUTE_INFORMATION, + .route.prefixlen = prefixlen, + .route.address = addr, + }); + if (p) { + if (offset != 0) + return -EEXIST; + + p->route.preference = preference; + p->route.lifetime = lifetime; + p->route.valid_until = valid_until; + return 0; + } + + p = ndisc_option_new(SD_NDISC_OPTION_ROUTE_INFORMATION, offset); + if (!p) + return -ENOMEM; + + p->route = (sd_ndisc_route) { + .preference = preference, + .prefixlen = prefixlen, + .address = addr, + .lifetime = lifetime, + .valid_until = valid_until, + }; + + return ndisc_option_consume(options, p); +} + +static int ndisc_option_parse_route(Set **options, size_t offset, size_t len, const uint8_t *opt) { + assert(options); + assert(opt); + + if (!IN_SET(len, 1*8, 2*8, 3*8)) + return -EBADMSG; + + if (opt[0] != SD_NDISC_OPTION_ROUTE_INFORMATION) + return -EBADMSG; + + uint8_t prefixlen = opt[2]; + if (prefixlen > 128) + return -EBADMSG; + + if (len < (size_t) (DIV_ROUND_UP(prefixlen, 64) + 1) * 8) + return -EBADMSG; + + uint8_t preference = (opt[3] >> 3) & 0x03; + usec_t lifetime = unaligned_be32_sec_to_usec(opt + 4, /* max_as_infinity = */ true); + + struct in6_addr prefix; + memcpy(&prefix, opt + 8, len - 8); + in6_addr_mask(&prefix, prefixlen); + + return ndisc_option_add_route(options, offset, preference, prefixlen, &prefix, lifetime); +} + +static int ndisc_option_build_route(const sd_ndisc_option *option, usec_t timestamp, uint8_t **ret) { + assert(option); + assert(option->type == SD_NDISC_OPTION_ROUTE_INFORMATION); + assert(option->route.prefixlen <= 128); + assert(ret); + + size_t len = 1 + DIV_ROUND_UP(option->route.prefixlen, 64); + be32_t lifetime = usec_to_be32_sec(MIN(option->route.lifetime, + usec_sub_unsigned(option->route.valid_until, timestamp))); + + _cleanup_free_ uint8_t *buf = new(uint8_t, len * 8); + if (!buf) + return -ENOMEM; + + buf[0] = SD_NDISC_OPTION_ROUTE_INFORMATION; + buf[1] = len; + buf[2] = option->route.prefixlen; + buf[3] = option->route.preference << 3; + memcpy(buf + 4, &lifetime, sizeof(be32_t)); + memcpy_safe(buf + 8, &option->route.address, (len - 1) * 8); + + *ret = TAKE_PTR(buf); + return 0; +} + +int ndisc_option_add_rdnss_internal( + Set **options, + size_t offset, + size_t n_addresses, + const struct in6_addr *addresses, + usec_t lifetime, + usec_t valid_until) { + + assert(options); + assert(addresses); + + if (n_addresses == 0) + return -EINVAL; + + _cleanup_free_ struct in6_addr *addrs = newdup(struct in6_addr, addresses, n_addresses); + if (!addrs) + return -ENOMEM; + + sd_ndisc_option *p = ndisc_option_new(SD_NDISC_OPTION_RDNSS, offset); + if (!p) + return -ENOMEM; + + p->rdnss = (sd_ndisc_rdnss) { + .n_addresses = n_addresses, + .addresses = TAKE_PTR(addrs), + .lifetime = lifetime, + .valid_until = valid_until, + }; + + return ndisc_option_consume(options, p); +} + +static int ndisc_option_parse_rdnss(Set **options, size_t offset, size_t len, const uint8_t *opt) { + assert(options); + assert(opt); + + if (len < 8 + sizeof(struct in6_addr) || (len % sizeof(struct in6_addr)) != 8) + return -EBADMSG; + + if (opt[0] != SD_NDISC_OPTION_RDNSS) + return -EBADMSG; + + usec_t lifetime = unaligned_be32_sec_to_usec(opt + 4, /* max_as_infinity = */ true); + size_t n_addrs = len / sizeof(struct in6_addr); + + return ndisc_option_add_rdnss(options, offset, n_addrs, (const struct in6_addr*) (opt + 8), lifetime); +} + +static int ndisc_option_build_rdnss(const sd_ndisc_option *option, usec_t timestamp, uint8_t **ret) { + assert(option); + assert(option->type == SD_NDISC_OPTION_RDNSS); + assert(ret); + + size_t len = option->rdnss.n_addresses * 2 + 1; + be32_t lifetime = usec_to_be32_sec(MIN(option->rdnss.lifetime, + usec_sub_unsigned(option->rdnss.valid_until, timestamp))); + + _cleanup_free_ uint8_t *buf = new(uint8_t, len * 8); + if (!buf) + return -ENOMEM; + + buf[0] = SD_NDISC_OPTION_RDNSS; + buf[1] = len; + buf[2] = 0; + buf[3] = 0; + memcpy(buf + 4, &lifetime, sizeof(be32_t)); + memcpy(buf + 8, option->rdnss.addresses, sizeof(struct in6_addr) * option->rdnss.n_addresses); + + *ret = TAKE_PTR(buf); + return 0; +} + +int ndisc_option_add_flags_extension(Set **options, size_t offset, uint64_t flags) { + assert(options); + + if ((flags & UINT64_C(0x00ffffffffffff00)) != flags) + return -EINVAL; + + sd_ndisc_option *p = ndisc_option_get_by_type(*options, SD_NDISC_OPTION_FLAGS_EXTENSION); + if (p) { + if (offset != 0) + return -EEXIST; + + p->extended_flags = flags; + return 0; + } + + p = ndisc_option_new(SD_NDISC_OPTION_FLAGS_EXTENSION, offset); + if (!p) + return -ENOMEM; + + p->extended_flags = flags; + + return ndisc_option_consume(options, p); +} + +static int ndisc_option_parse_flags_extension(Set **options, size_t offset, size_t len, const uint8_t *opt) { + assert(options); + assert(opt); + + if (len != 8) + return -EBADMSG; + + if (opt[0] != SD_NDISC_OPTION_FLAGS_EXTENSION) + return -EBADMSG; + + uint64_t flags = (unaligned_read_be64(opt) & UINT64_C(0xffffffffffff0000)) >> 8; + return ndisc_option_add_flags_extension(options, offset, flags); +} + +static int ndisc_option_build_flags_extension(const sd_ndisc_option *option, uint8_t **ret) { + assert(option); + assert(option->type == SD_NDISC_OPTION_FLAGS_EXTENSION); + assert(ret); + + _cleanup_free_ uint8_t *buf = new(uint8_t, 8); + if (!buf) + return 0; + + unaligned_write_be64(buf, (option->extended_flags & UINT64_C(0x00ffffffffffff00)) << 8); + buf[0] = SD_NDISC_OPTION_FLAGS_EXTENSION; + buf[1] = 1; + + *ret = TAKE_PTR(buf); + return 0; +} + +int ndisc_option_add_dnssl_internal( + Set **options, + size_t offset, char * + const *domains, + usec_t lifetime, + usec_t valid_until) { + + int r; + + assert(options); + + if (strv_isempty(domains)) + return -EINVAL; + + STRV_FOREACH(s, domains) { + r = dns_name_is_valid(*s); + if (r < 0) + return r; + + if (is_localhost(*s) || dns_name_is_root(*s)) + return -EINVAL; + } + + _cleanup_strv_free_ char **copy = strv_copy(domains); + if (!copy) + return -ENOMEM; + + sd_ndisc_option *p = ndisc_option_new(SD_NDISC_OPTION_DNSSL, offset); + if (!p) + return -ENOMEM; + + p->dnssl = (sd_ndisc_dnssl) { + .domains = TAKE_PTR(copy), + .lifetime = lifetime, + .valid_until = valid_until, + }; + + return ndisc_option_consume(options, p); +} + +static int ndisc_option_parse_dnssl(Set **options, size_t offset, size_t len, const uint8_t *opt) { + int r; + + assert(options); + assert(opt); + + if (len < 2*8) + return -EBADMSG; + + if (opt[0] != SD_NDISC_OPTION_DNSSL) + return -EBADMSG; + + usec_t lifetime = unaligned_be32_sec_to_usec(opt + 4, /* max_as_infinity = */ true); + + _cleanup_strv_free_ char **l = NULL; + _cleanup_free_ char *e = NULL; + size_t n = 0; + for (size_t c, pos = 8; pos < len; pos += c) { + + c = opt[pos]; + pos++; + + if (c == 0) { + /* Found NUL termination */ + + if (n > 0) { + _cleanup_free_ char *normalized = NULL; + + e[n] = 0; + r = dns_name_normalize(e, 0, &normalized); + if (r < 0) + return r; + + /* Ignore the root domain name or "localhost" and friends */ + if (!is_localhost(normalized) && !dns_name_is_root(normalized)) { + r = strv_consume(&l, TAKE_PTR(normalized)); + if (r < 0) + return r; + } + } + + n = 0; + continue; + } + + /* Check for compression (which is not allowed) */ + if (c > 63) + return -EBADMSG; + + if (pos + c >= len) + return -EBADMSG; + + if (!GREEDY_REALLOC(e, n + (n != 0) + DNS_LABEL_ESCAPED_MAX + 1U)) + return -ENOMEM; + + if (n != 0) + e[n++] = '.'; + + r = dns_label_escape((const char*) (opt + pos), c, e + n, DNS_LABEL_ESCAPED_MAX); + if (r < 0) + return r; + + n += r; + } + + if (n > 0) /* Not properly NUL terminated */ + return -EBADMSG; + + return ndisc_option_add_dnssl(options, offset, l, lifetime); +} + + static int ndisc_option_build_dnssl(const sd_ndisc_option *option, usec_t timestamp, uint8_t **ret) { + int r; + + assert(option); + assert(option->type == SD_NDISC_OPTION_DNSSL); + assert(ret); + + size_t len = 8; + STRV_FOREACH(s, option->dnssl.domains) + len += strlen(*s) + 2; + len = DIV_ROUND_UP(len, 8); + + be32_t lifetime = usec_to_be32_sec(MIN(option->dnssl.lifetime, + usec_sub_unsigned(option->dnssl.valid_until, timestamp))); + + _cleanup_free_ uint8_t *buf = new(uint8_t, len * 8); + if (!buf) + return -ENOMEM; + + buf[0] = SD_NDISC_OPTION_DNSSL; + buf[1] = len; + buf[2] = 0; + buf[3] = 0; + memcpy(buf + 4, &lifetime, sizeof(be32_t)); + + size_t remaining = len * 8 - 8; + uint8_t *p = buf + 8; + + STRV_FOREACH(s, option->dnssl.domains) { + r = dns_name_to_wire_format(*s, p, remaining, /* canonical = */ false); + if (r < 0) + return r; + + assert(remaining >= (size_t) r); + p += r; + remaining -= r; + } + + memzero(p, remaining); + + *ret = TAKE_PTR(buf); + return 0; +} + +int ndisc_option_add_captive_portal(Set **options, size_t offset, const char *portal) { + assert(options); + + if (isempty(portal)) + return -EINVAL; + + if (!in_charset(portal, URI_VALID)) + return -EINVAL; + + sd_ndisc_option *p = ndisc_option_get_by_type(*options, SD_NDISC_OPTION_CAPTIVE_PORTAL); + if (p) { + if (offset != 0) + return -EEXIST; + + return free_and_strdup(&p->captive_portal, portal); + } + + _cleanup_free_ char *copy = strdup(portal); + if (!copy) + return -ENOMEM; + + p = ndisc_option_new(SD_NDISC_OPTION_CAPTIVE_PORTAL, offset); + if (!p) + return -ENOMEM; + + p->captive_portal = TAKE_PTR(copy); + + return ndisc_option_consume(options, p); +} + +static int ndisc_option_parse_captive_portal(Set **options, size_t offset, size_t len, const uint8_t *opt) { + assert(options); + assert(opt); + + if (len < 8) + return -EBADMSG; + + if (opt[0] != SD_NDISC_OPTION_CAPTIVE_PORTAL) + return -EBADMSG; + + _cleanup_free_ char *portal = memdup_suffix0(opt + 2, len - 2); + if (!portal) + return -ENOMEM; + + size_t size = strlen(portal); + if (size == 0) + return -EBADMSG; + + /* Check that the message is not truncated by an embedded NUL. + * NUL padding to a multiple of 8 is expected. */ + if (DIV_ROUND_UP(size + 2, 8) * 8 != len && DIV_ROUND_UP(size + 3, 8) * 8 != len) + return -EBADMSG; + + return ndisc_option_add_captive_portal(options, offset, portal); +} + +static int ndisc_option_build_captive_portal(const sd_ndisc_option *option, uint8_t **ret) { + assert(option); + assert(option->type == SD_NDISC_OPTION_CAPTIVE_PORTAL); + assert(ret); + + size_t len_portal = strlen(option->captive_portal); + size_t len = DIV_ROUND_UP(len_portal + 1 + 2, 8); + + _cleanup_free_ uint8_t *buf = new(uint8_t, len * 8); + if (!buf) + return -ENOMEM; + + buf[0] = SD_NDISC_OPTION_CAPTIVE_PORTAL; + buf[1] = len; + + uint8_t *p = mempcpy(buf + 2, option->captive_portal, len_portal); + size_t remaining = len * 8 - 2 - len_portal; + + memzero(p, remaining); + + *ret = TAKE_PTR(buf); + return 0; +} + +static const uint8_t prefix_length_code_to_prefix_length[_PREFIX_LENGTH_CODE_MAX] = { + [PREFIX_LENGTH_CODE_96] = 96, + [PREFIX_LENGTH_CODE_64] = 64, + [PREFIX_LENGTH_CODE_56] = 56, + [PREFIX_LENGTH_CODE_48] = 48, + [PREFIX_LENGTH_CODE_40] = 40, + [PREFIX_LENGTH_CODE_32] = 32, +}; + +int pref64_prefix_length_to_plc(uint8_t prefixlen, uint8_t *ret) { + for (size_t i = 0; i < ELEMENTSOF(prefix_length_code_to_prefix_length); i++) + if (prefix_length_code_to_prefix_length[i] == prefixlen) { + if (ret) + *ret = i; + return 0; + } + + return -EINVAL; +} + +static int pref64_lifetime_and_plc_parse(uint16_t lifetime_and_plc, uint8_t *ret_prefixlen, usec_t *ret_lifetime) { + uint16_t plc = lifetime_and_plc & PREF64_PLC_MASK; + if (plc >= _PREFIX_LENGTH_CODE_MAX) + return -EINVAL; + + if (ret_prefixlen) + *ret_prefixlen = prefix_length_code_to_prefix_length[plc]; + if (ret_lifetime) + *ret_lifetime = (lifetime_and_plc & PREF64_SCALED_LIFETIME_MASK) * USEC_PER_SEC; + return 0; +} + +int ndisc_option_add_prefix64_internal( + Set **options, + size_t offset, + uint8_t prefixlen, + const struct in6_addr *prefix, + usec_t lifetime, + usec_t valid_until) { + + int r; + + assert(options); + assert(prefix); + + r = pref64_prefix_length_to_plc(prefixlen, NULL); + if (r < 0) + return r; + + if (lifetime > PREF64_MAX_LIFETIME_USEC) + return -EINVAL; + + struct in6_addr addr = *prefix; + in6_addr_mask(&addr, prefixlen); + + sd_ndisc_option *p = ndisc_option_get( + *options, + &(const sd_ndisc_option) { + .type = SD_NDISC_OPTION_PREF64, + .prefix64.prefixlen = prefixlen, + .prefix64.prefix = addr, + }); + if (p) { + if (offset != 0) + return -EEXIST; + + p->prefix64.lifetime = lifetime; + p->prefix64.valid_until = valid_until; + return 0; + } + + p = ndisc_option_new(SD_NDISC_OPTION_PREF64, offset); + if (!p) + return -ENOMEM; + + p->prefix64 = (sd_ndisc_prefix64) { + .prefixlen = prefixlen, + .prefix = addr, + .lifetime = lifetime, + .valid_until = valid_until, + }; + + return ndisc_option_consume(options, p); +} + +static int ndisc_option_parse_prefix64(Set **options, size_t offset, size_t len, const uint8_t *opt) { + int r; + + assert(options); + assert(opt); + + if (len != 2*8) + return -EBADMSG; + + if (opt[0] != SD_NDISC_OPTION_PREF64) + return -EBADMSG; + + uint8_t prefixlen; + usec_t lifetime; + r = pref64_lifetime_and_plc_parse(unaligned_read_be16(opt + 2), &prefixlen, &lifetime); + if (r < 0) + return r; + + struct in6_addr prefix; + memcpy(&prefix, opt + 4, len - 4); + in6_addr_mask(&prefix, prefixlen); + + return ndisc_option_add_prefix64(options, offset, prefixlen, &prefix, lifetime); +} + +static int ndisc_option_build_prefix64(const sd_ndisc_option *option, usec_t timestamp, uint8_t **ret) { + int r; + + assert(option); + assert(option->type == SD_NDISC_OPTION_PREF64); + assert(ret); + + uint8_t code; + r = pref64_prefix_length_to_plc(option->prefix64.prefixlen, &code); + if (r < 0) + return r; + + uint16_t lifetime = (uint16_t) DIV_ROUND_UP(MIN(option->prefix64.lifetime, + usec_sub_unsigned(option->prefix64.valid_until, timestamp)), + USEC_PER_SEC) & PREF64_SCALED_LIFETIME_MASK; + + _cleanup_free_ uint8_t *buf = new(uint8_t, 2 * 8); + if (!buf) + return -ENOMEM; + + buf[0] = SD_NDISC_OPTION_PREF64; + buf[1] = 2; + unaligned_write_be16(buf + 2, lifetime | code); + memcpy(buf + 4, &option->prefix64.prefix, 12); + + *ret = TAKE_PTR(buf); + return 0; +} + +static int ndisc_option_parse_default(Set **options, size_t offset, size_t len, const uint8_t *opt) { + assert(options); + assert(opt); + assert(len > 0); + + sd_ndisc_option *p = ndisc_option_new(opt[0], offset); + if (!p) + return -ENOMEM; + + return ndisc_option_consume(options, p); +} + +static int ndisc_header_size(uint8_t icmp6_type) { + switch (icmp6_type) { + case ND_ROUTER_SOLICIT: + return sizeof(struct nd_router_solicit); + case ND_ROUTER_ADVERT: + return sizeof(struct nd_router_advert); + case ND_NEIGHBOR_SOLICIT: + return sizeof(struct nd_neighbor_solicit); + case ND_NEIGHBOR_ADVERT: + return sizeof(struct nd_neighbor_advert); + case ND_REDIRECT: + return sizeof(struct nd_redirect); + default: + return -EINVAL; + } +} + +int ndisc_parse_options(ICMP6Packet *packet, Set **ret_options) { + _cleanup_set_free_ Set *options = NULL; + int r; + + assert(packet); + assert(ret_options); + + r = icmp6_packet_get_type(packet); + if (r < 0) + return r; + + r = ndisc_header_size(r); + if (r < 0) + return -EBADMSG; + size_t header_size = r; + + if (packet->raw_size < header_size) + return -EBADMSG; + + for (size_t length, offset = header_size; offset < packet->raw_size; offset += length) { + uint8_t type; + const uint8_t *opt; + + r = ndisc_option_parse(packet, offset, &type, &length, &opt); + if (r < 0) + return log_debug_errno(r, "Failed to parse NDisc option header: %m"); + + switch (type) { + case 0: + r = -EBADMSG; + break; + + case SD_NDISC_OPTION_SOURCE_LL_ADDRESS: + case SD_NDISC_OPTION_TARGET_LL_ADDRESS: + r = ndisc_option_parse_link_layer_address(&options, offset, length, opt); + break; + + case SD_NDISC_OPTION_PREFIX_INFORMATION: + r = ndisc_option_parse_prefix(&options, offset, length, opt); + break; + + case SD_NDISC_OPTION_REDIRECTED_HEADER: + r = ndisc_option_parse_redirected_header(&options, offset, length, opt); + break; + + case SD_NDISC_OPTION_MTU: + r = ndisc_option_parse_mtu(&options, offset, length, opt); + break; + + case SD_NDISC_OPTION_HOME_AGENT: + r = ndisc_option_parse_home_agent(&options, offset, length, opt); + break; + + case SD_NDISC_OPTION_ROUTE_INFORMATION: + r = ndisc_option_parse_route(&options, offset, length, opt); + break; + + case SD_NDISC_OPTION_RDNSS: + r = ndisc_option_parse_rdnss(&options, offset, length, opt); + break; + + case SD_NDISC_OPTION_FLAGS_EXTENSION: + r = ndisc_option_parse_flags_extension(&options, offset, length, opt); + break; + + case SD_NDISC_OPTION_DNSSL: + r = ndisc_option_parse_dnssl(&options, offset, length, opt); + break; + + case SD_NDISC_OPTION_CAPTIVE_PORTAL: + r = ndisc_option_parse_captive_portal(&options, offset, length, opt); + break; + + case SD_NDISC_OPTION_PREF64: + r = ndisc_option_parse_prefix64(&options, offset, length, opt); + break; + + default: + r = ndisc_option_parse_default(&options, offset, length, opt); + } + if (r == -ENOMEM) + return log_oom_debug(); + if (r < 0) + log_debug_errno(r, "Failed to parse NDisc option %u, ignoring: %m", type); + } + + *ret_options = TAKE_PTR(options); + return 0; +} + +int ndisc_option_get_mac(Set *options, uint8_t type, struct ether_addr *ret) { + assert(IN_SET(type, SD_NDISC_OPTION_SOURCE_LL_ADDRESS, SD_NDISC_OPTION_TARGET_LL_ADDRESS)); + + sd_ndisc_option *p = ndisc_option_get_by_type(options, type); + if (!p) + return -ENODATA; + + if (ret) + *ret = p->mac; + return 0; +} + +int ndisc_send(int fd, const struct in6_addr *dst, const struct icmp6_hdr *hdr, Set *options, usec_t timestamp) { + int r; + + assert(fd >= 0); + assert(dst); + assert(hdr); + + size_t n; + _cleanup_free_ sd_ndisc_option **list = NULL; + r = set_dump_sorted(options, (void***) &list, &n); + if (r < 0) + return r; + + struct iovec *iov = NULL; + size_t n_iov = 0; + CLEANUP_ARRAY(iov, n_iov, iovec_array_free); + + iov = new(struct iovec, 1 + n); + if (!iov) + return -ENOMEM; + + r = ndisc_header_size(hdr->icmp6_type); + if (r < 0) + return r; + size_t hdr_size = r; + + _cleanup_free_ uint8_t *copy = newdup(uint8_t, hdr, hdr_size); + if (!copy) + return -ENOMEM; + + iov[n_iov++] = IOVEC_MAKE(TAKE_PTR(copy), hdr_size); + + FOREACH_ARRAY(p, list, n) { + _cleanup_free_ uint8_t *buf = NULL; + sd_ndisc_option *option = *p; + + switch (option->type) { + case 0: + r = ndisc_option_build_raw(option, &buf); + break; + + case SD_NDISC_OPTION_SOURCE_LL_ADDRESS: + case SD_NDISC_OPTION_TARGET_LL_ADDRESS: + r = ndisc_option_build_link_layer_address(option, &buf); + break; + + case SD_NDISC_OPTION_PREFIX_INFORMATION: + r = ndisc_option_build_prefix(option, timestamp, &buf); + break; + + case SD_NDISC_OPTION_REDIRECTED_HEADER: + r = ndisc_option_build_redirected_header(option, &buf); + break; + + case SD_NDISC_OPTION_MTU: + r = ndisc_option_build_mtu(option, &buf); + break; + + case SD_NDISC_OPTION_HOME_AGENT: + r = ndisc_option_build_home_agent(option, timestamp, &buf); + break; + + case SD_NDISC_OPTION_ROUTE_INFORMATION: + r = ndisc_option_build_route(option, timestamp, &buf); + break; + + case SD_NDISC_OPTION_RDNSS: + r = ndisc_option_build_rdnss(option, timestamp, &buf); + break; + + case SD_NDISC_OPTION_FLAGS_EXTENSION: + r = ndisc_option_build_flags_extension(option, &buf); + break; + + case SD_NDISC_OPTION_DNSSL: + r = ndisc_option_build_dnssl(option, timestamp, &buf); + break; + + case SD_NDISC_OPTION_CAPTIVE_PORTAL: + r = ndisc_option_build_captive_portal(option, &buf); + break; + + case SD_NDISC_OPTION_PREF64: + r = ndisc_option_build_prefix64(option, timestamp, &buf); + break; + + default: + continue; + } + if (r == -ENOMEM) + return log_oom_debug(); + if (r < 0) + log_debug_errno(r, "Failed to build NDisc option %u, ignoring: %m", option->type); + + iov[n_iov++] = IOVEC_MAKE(buf, buf[1] * 8); + TAKE_PTR(buf); + } + + return icmp6_send(fd, dst, iov, n_iov); +} |