diff options
Diffstat (limited to '')
| -rw-r--r-- | src/libsystemd/sd-netlink/netlink-message.c | 1421 |
1 files changed, 1421 insertions, 0 deletions
diff --git a/src/libsystemd/sd-netlink/netlink-message.c b/src/libsystemd/sd-netlink/netlink-message.c new file mode 100644 index 0000000..000a50e --- /dev/null +++ b/src/libsystemd/sd-netlink/netlink-message.c @@ -0,0 +1,1421 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ + +#include <netinet/in.h> +#include <stdbool.h> +#include <unistd.h> + +#include "sd-netlink.h" + +#include "alloc-util.h" +#include "format-util.h" +#include "memory-util.h" +#include "netlink-internal.h" +#include "netlink-types.h" +#include "netlink-util.h" +#include "socket-util.h" +#include "strv.h" + +#define GET_CONTAINER(m, i) ((struct rtattr*)((uint8_t*)(m)->hdr + (m)->containers[i].offset)) + +#define RTA_TYPE(rta) ((rta)->rta_type & NLA_TYPE_MASK) +#define RTA_FLAGS(rta) ((rta)->rta_type & ~NLA_TYPE_MASK) + +int message_new_empty(sd_netlink *nl, sd_netlink_message **ret) { + sd_netlink_message *m; + + assert(nl); + assert(ret); + + /* Note that 'nl' is currently unused, if we start using it internally we must take care to + * avoid problems due to mutual references between buses and their queued messages. See sd-bus. */ + + m = new(sd_netlink_message, 1); + if (!m) + return -ENOMEM; + + *m = (sd_netlink_message) { + .n_ref = 1, + .protocol = nl->protocol, + .sealed = false, + }; + + *ret = m; + return 0; +} + +int message_new_full( + sd_netlink *nl, + uint16_t nlmsg_type, + const NLAPolicySet *policy_set, + size_t header_size, + sd_netlink_message **ret) { + + _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL; + size_t size; + int r; + + assert(nl); + assert(policy_set); + assert(ret); + + size = NLMSG_SPACE(header_size); + assert(size >= sizeof(struct nlmsghdr)); + + r = message_new_empty(nl, &m); + if (r < 0) + return r; + + m->containers[0].policy_set = policy_set; + + m->hdr = malloc0(size); + if (!m->hdr) + return -ENOMEM; + + m->hdr->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK; + m->hdr->nlmsg_len = size; + m->hdr->nlmsg_type = nlmsg_type; + + *ret = TAKE_PTR(m); + return 0; +} + +int message_new(sd_netlink *nl, sd_netlink_message **ret, uint16_t nlmsg_type) { + const NLAPolicySet *policy_set; + size_t size; + int r; + + assert_return(nl, -EINVAL); + assert_return(ret, -EINVAL); + + r = netlink_get_policy_set_and_header_size(nl, nlmsg_type, &policy_set, &size); + if (r < 0) + return r; + + return message_new_full(nl, nlmsg_type, policy_set, size, ret); +} + +int message_new_synthetic_error(sd_netlink *nl, int error, uint32_t serial, sd_netlink_message **ret) { + struct nlmsgerr *err; + int r; + + assert(error <= 0); + + r = message_new(nl, ret, NLMSG_ERROR); + if (r < 0) + return r; + + message_seal(*ret); + (*ret)->hdr->nlmsg_seq = serial; + + err = NLMSG_DATA((*ret)->hdr); + err->error = error; + + return 0; +} + +int sd_netlink_message_set_request_dump(sd_netlink_message *m, int dump) { + assert_return(m, -EINVAL); + assert_return(m->hdr, -EINVAL); + assert_return(m->protocol != NETLINK_ROUTE || + IN_SET(m->hdr->nlmsg_type, + RTM_GETLINK, RTM_GETLINKPROP, RTM_GETADDR, RTM_GETROUTE, RTM_GETNEIGH, + RTM_GETRULE, RTM_GETADDRLABEL, RTM_GETNEXTHOP, RTM_GETQDISC, RTM_GETTCLASS), + -EINVAL); + + SET_FLAG(m->hdr->nlmsg_flags, NLM_F_DUMP, dump); + + return 0; +} + +DEFINE_TRIVIAL_REF_FUNC(sd_netlink_message, sd_netlink_message); + +sd_netlink_message* sd_netlink_message_unref(sd_netlink_message *m) { + while (m && --m->n_ref == 0) { + unsigned i; + + free(m->hdr); + + for (i = 0; i <= m->n_containers; i++) + free(m->containers[i].attributes); + + sd_netlink_message *t = m; + m = m->next; + free(t); + } + + return NULL; +} + +int sd_netlink_message_get_type(sd_netlink_message *m, uint16_t *ret) { + assert_return(m, -EINVAL); + assert_return(ret, -EINVAL); + + *ret = m->hdr->nlmsg_type; + + return 0; +} + +int sd_netlink_message_set_flags(sd_netlink_message *m, uint16_t flags) { + assert_return(m, -EINVAL); + assert_return(flags != 0, -EINVAL); + + m->hdr->nlmsg_flags = flags; + + return 0; +} + +int sd_netlink_message_is_broadcast(sd_netlink_message *m) { + assert_return(m, -EINVAL); + + return m->multicast_group != 0; +} + +/* If successful the updated message will be correctly aligned, if unsuccessful the old message is untouched. */ +static int add_rtattr(sd_netlink_message *m, uint16_t attr_type, const void *data, size_t data_length) { + size_t message_length; + struct nlmsghdr *new_hdr; + struct rtattr *rta; + int offset; + + assert(m); + assert(m->hdr); + assert(!m->sealed); + assert(NLMSG_ALIGN(m->hdr->nlmsg_len) == m->hdr->nlmsg_len); + assert(!data || data_length > 0); + + /* get the new message size (with padding at the end) */ + message_length = m->hdr->nlmsg_len + RTA_SPACE(data_length); + + /* buffer should be smaller than both one page or 8K to be accepted by the kernel */ + if (message_length > MIN(page_size(), 8192UL)) + return -ENOBUFS; + + /* realloc to fit the new attribute */ + new_hdr = realloc(m->hdr, message_length); + if (!new_hdr) + return -ENOMEM; + m->hdr = new_hdr; + + /* get pointer to the attribute we are about to add */ + rta = (struct rtattr *) ((uint8_t *) m->hdr + m->hdr->nlmsg_len); + + rtattr_append_attribute_internal(rta, attr_type, data, data_length); + + /* if we are inside containers, extend them */ + for (unsigned i = 0; i < m->n_containers; i++) + GET_CONTAINER(m, i)->rta_len += RTA_SPACE(data_length); + + /* update message size */ + offset = m->hdr->nlmsg_len; + m->hdr->nlmsg_len = message_length; + + /* return old message size */ + return offset; +} + +static int message_attribute_has_type(sd_netlink_message *m, size_t *ret_size, uint16_t attr_type, NLAType type) { + const NLAPolicy *policy; + + assert(m); + + policy = policy_set_get_policy(m->containers[m->n_containers].policy_set, attr_type); + if (!policy) + return -EOPNOTSUPP; + + if (policy_get_type(policy) != type) + return -EINVAL; + + if (ret_size) + *ret_size = policy_get_size(policy); + return 0; +} + +int sd_netlink_message_append_string(sd_netlink_message *m, uint16_t attr_type, const char *data) { + size_t length, size; + int r; + + assert_return(m, -EINVAL); + assert_return(!m->sealed, -EPERM); + assert_return(data, -EINVAL); + + r = message_attribute_has_type(m, &size, attr_type, NETLINK_TYPE_STRING); + if (r < 0) + return r; + + if (size) { + length = strnlen(data, size+1); + if (length > size) + return -EINVAL; + } else + length = strlen(data); + + r = add_rtattr(m, attr_type, data, length + 1); + if (r < 0) + return r; + + return 0; +} + +int sd_netlink_message_append_strv(sd_netlink_message *m, uint16_t attr_type, const char* const *data) { + size_t length, size; + int r; + + assert_return(m, -EINVAL); + assert_return(!m->sealed, -EPERM); + assert_return(data, -EINVAL); + + r = message_attribute_has_type(m, &size, attr_type, NETLINK_TYPE_STRING); + if (r < 0) + return r; + + STRV_FOREACH(p, data) { + if (size) { + length = strnlen(*p, size+1); + if (length > size) + return -EINVAL; + } else + length = strlen(*p); + + r = add_rtattr(m, attr_type, *p, length + 1); + if (r < 0) + return r; + } + + return 0; +} + +int sd_netlink_message_append_flag(sd_netlink_message *m, uint16_t attr_type) { + size_t size; + int r; + + assert_return(m, -EINVAL); + assert_return(!m->sealed, -EPERM); + + r = message_attribute_has_type(m, &size, attr_type, NETLINK_TYPE_FLAG); + if (r < 0) + return r; + + r = add_rtattr(m, attr_type, NULL, 0); + if (r < 0) + return r; + + return 0; +} + +int sd_netlink_message_append_u8(sd_netlink_message *m, uint16_t attr_type, uint8_t data) { + int r; + + assert_return(m, -EINVAL); + assert_return(!m->sealed, -EPERM); + + r = message_attribute_has_type(m, NULL, attr_type, NETLINK_TYPE_U8); + if (r < 0) + return r; + + r = add_rtattr(m, attr_type, &data, sizeof(uint8_t)); + if (r < 0) + return r; + + return 0; +} + +int sd_netlink_message_append_u16(sd_netlink_message *m, uint16_t attr_type, uint16_t data) { + int r; + + assert_return(m, -EINVAL); + assert_return(!m->sealed, -EPERM); + + r = message_attribute_has_type(m, NULL, attr_type, NETLINK_TYPE_U16); + if (r < 0) + return r; + + r = add_rtattr(m, attr_type, &data, sizeof(uint16_t)); + if (r < 0) + return r; + + return 0; +} + +int sd_netlink_message_append_u32(sd_netlink_message *m, uint16_t attr_type, uint32_t data) { + int r; + + assert_return(m, -EINVAL); + assert_return(!m->sealed, -EPERM); + + r = message_attribute_has_type(m, NULL, attr_type, NETLINK_TYPE_U32); + if (r < 0) + return r; + + r = add_rtattr(m, attr_type, &data, sizeof(uint32_t)); + if (r < 0) + return r; + + return 0; +} + +int sd_netlink_message_append_u64(sd_netlink_message *m, uint16_t attr_type, uint64_t data) { + int r; + + assert_return(m, -EINVAL); + assert_return(!m->sealed, -EPERM); + + r = message_attribute_has_type(m, NULL, attr_type, NETLINK_TYPE_U64); + if (r < 0) + return r; + + r = add_rtattr(m, attr_type, &data, sizeof(uint64_t)); + if (r < 0) + return r; + + return 0; +} + +int sd_netlink_message_append_s8(sd_netlink_message *m, uint16_t attr_type, int8_t data) { + int r; + + assert_return(m, -EINVAL); + assert_return(!m->sealed, -EPERM); + + r = message_attribute_has_type(m, NULL, attr_type, NETLINK_TYPE_S8); + if (r < 0) + return r; + + r = add_rtattr(m, attr_type, &data, sizeof(int8_t)); + if (r < 0) + return r; + + return 0; +} + +int sd_netlink_message_append_s16(sd_netlink_message *m, uint16_t attr_type, int16_t data) { + int r; + + assert_return(m, -EINVAL); + assert_return(!m->sealed, -EPERM); + + r = message_attribute_has_type(m, NULL, attr_type, NETLINK_TYPE_S16); + if (r < 0) + return r; + + r = add_rtattr(m, attr_type, &data, sizeof(int16_t)); + if (r < 0) + return r; + + return 0; +} + +int sd_netlink_message_append_s32(sd_netlink_message *m, uint16_t attr_type, int32_t data) { + int r; + + assert_return(m, -EINVAL); + assert_return(!m->sealed, -EPERM); + + r = message_attribute_has_type(m, NULL, attr_type, NETLINK_TYPE_S32); + if (r < 0) + return r; + + r = add_rtattr(m, attr_type, &data, sizeof(int32_t)); + if (r < 0) + return r; + + return 0; +} + +int sd_netlink_message_append_s64(sd_netlink_message *m, uint16_t attr_type, int64_t data) { + int r; + + assert_return(m, -EINVAL); + assert_return(!m->sealed, -EPERM); + + r = message_attribute_has_type(m, NULL, attr_type, NETLINK_TYPE_S64); + if (r < 0) + return r; + + r = add_rtattr(m, attr_type, &data, sizeof(int64_t)); + if (r < 0) + return r; + + return 0; +} + +int sd_netlink_message_append_data(sd_netlink_message *m, uint16_t attr_type, const void *data, size_t len) { + int r; + + assert_return(m, -EINVAL); + assert_return(!m->sealed, -EPERM); + + r = add_rtattr(m, attr_type, data, len); + if (r < 0) + return r; + + return 0; +} + +int sd_netlink_message_append_container_data( + sd_netlink_message *m, + uint16_t container_type, + uint16_t attr_type, + const void *data, + size_t len) { + + int r; + + assert_return(m, -EINVAL); + assert_return(!m->sealed, -EPERM); + + r = sd_netlink_message_open_container(m, container_type); + if (r < 0) + return r; + + r = sd_netlink_message_append_data(m, attr_type, data, len); + if (r < 0) + return r; + + return sd_netlink_message_close_container(m); +} + +int netlink_message_append_in_addr_union(sd_netlink_message *m, uint16_t attr_type, int family, const union in_addr_union *data) { + int r; + + assert_return(m, -EINVAL); + assert_return(!m->sealed, -EPERM); + assert_return(data, -EINVAL); + assert_return(IN_SET(family, AF_INET, AF_INET6), -EINVAL); + + r = message_attribute_has_type(m, NULL, attr_type, NETLINK_TYPE_IN_ADDR); + if (r < 0) + return r; + + r = add_rtattr(m, attr_type, data, FAMILY_ADDRESS_SIZE(family)); + if (r < 0) + return r; + + return 0; +} + +int sd_netlink_message_append_in_addr(sd_netlink_message *m, uint16_t attr_type, const struct in_addr *data) { + return netlink_message_append_in_addr_union(m, attr_type, AF_INET, (const union in_addr_union *) data); +} + +int sd_netlink_message_append_in6_addr(sd_netlink_message *m, uint16_t attr_type, const struct in6_addr *data) { + return netlink_message_append_in_addr_union(m, attr_type, AF_INET6, (const union in_addr_union *) data); +} + +int netlink_message_append_sockaddr_union(sd_netlink_message *m, uint16_t attr_type, const union sockaddr_union *data) { + int r; + + assert_return(m, -EINVAL); + assert_return(!m->sealed, -EPERM); + assert_return(data, -EINVAL); + assert_return(IN_SET(data->sa.sa_family, AF_INET, AF_INET6), -EINVAL); + + r = message_attribute_has_type(m, NULL, attr_type, NETLINK_TYPE_SOCKADDR); + if (r < 0) + return r; + + r = add_rtattr(m, attr_type, data, data->sa.sa_family == AF_INET ? sizeof(struct sockaddr_in) : sizeof(struct sockaddr_in6)); + if (r < 0) + return r; + + return 0; +} + +int sd_netlink_message_append_sockaddr_in(sd_netlink_message *m, uint16_t attr_type, const struct sockaddr_in *data) { + return netlink_message_append_sockaddr_union(m, attr_type, (const union sockaddr_union *) data); +} + +int sd_netlink_message_append_sockaddr_in6(sd_netlink_message *m, uint16_t attr_type, const struct sockaddr_in6 *data) { + return netlink_message_append_sockaddr_union(m, attr_type, (const union sockaddr_union *) data); +} + +int sd_netlink_message_append_ether_addr(sd_netlink_message *m, uint16_t attr_type, const struct ether_addr *data) { + int r; + + assert_return(m, -EINVAL); + assert_return(!m->sealed, -EPERM); + assert_return(data, -EINVAL); + + r = message_attribute_has_type(m, NULL, attr_type, NETLINK_TYPE_ETHER_ADDR); + if (r < 0) + return r; + + r = add_rtattr(m, attr_type, data, ETH_ALEN); + if (r < 0) + return r; + + return 0; +} + +int netlink_message_append_hw_addr(sd_netlink_message *m, uint16_t attr_type, const struct hw_addr_data *data) { + int r; + + assert_return(m, -EINVAL); + assert_return(!m->sealed, -EPERM); + assert_return(data, -EINVAL); + assert_return(data->length > 0, -EINVAL); + + r = message_attribute_has_type(m, NULL, attr_type, NETLINK_TYPE_ETHER_ADDR); + if (r < 0) + return r; + + r = add_rtattr(m, attr_type, data->bytes, data->length); + if (r < 0) + return r; + + return 0; +} + +int sd_netlink_message_append_cache_info(sd_netlink_message *m, uint16_t attr_type, const struct ifa_cacheinfo *info) { + int r; + + assert_return(m, -EINVAL); + assert_return(!m->sealed, -EPERM); + assert_return(info, -EINVAL); + + r = message_attribute_has_type(m, NULL, attr_type, NETLINK_TYPE_CACHE_INFO); + if (r < 0) + return r; + + r = add_rtattr(m, attr_type, info, sizeof(struct ifa_cacheinfo)); + if (r < 0) + return r; + + return 0; +} + +int sd_netlink_message_open_container(sd_netlink_message *m, uint16_t attr_type) { + size_t size; + int r; + + assert_return(m, -EINVAL); + assert_return(!m->sealed, -EPERM); + /* m->containers[m->n_containers + 1] is accessed both in read and write. Prevent access out of bound */ + assert_return(m->n_containers < (NETLINK_CONTAINER_DEPTH - 1), -ERANGE); + + r = message_attribute_has_type(m, &size, attr_type, NETLINK_TYPE_NESTED); + if (r < 0) { + const NLAPolicySetUnion *policy_set_union; + int family; + + r = message_attribute_has_type(m, &size, attr_type, NETLINK_TYPE_NESTED_UNION_BY_FAMILY); + if (r < 0) + return r; + + r = sd_rtnl_message_get_family(m, &family); + if (r < 0) + return r; + + policy_set_union = policy_set_get_policy_set_union( + m->containers[m->n_containers].policy_set, + attr_type); + if (!policy_set_union) + return -EOPNOTSUPP; + + m->containers[m->n_containers + 1].policy_set = + policy_set_union_get_policy_set_by_family( + policy_set_union, + family); + } else + m->containers[m->n_containers + 1].policy_set = + policy_set_get_policy_set( + m->containers[m->n_containers].policy_set, + attr_type); + if (!m->containers[m->n_containers + 1].policy_set) + return -EOPNOTSUPP; + + r = add_rtattr(m, attr_type | NLA_F_NESTED, NULL, size); + if (r < 0) + return r; + + m->containers[m->n_containers++].offset = r; + + return 0; +} + +int sd_netlink_message_open_container_union(sd_netlink_message *m, uint16_t attr_type, const char *key) { + const NLAPolicySetUnion *policy_set_union; + int r; + + assert_return(m, -EINVAL); + assert_return(!m->sealed, -EPERM); + assert_return(m->n_containers < (NETLINK_CONTAINER_DEPTH - 1), -ERANGE); + + r = message_attribute_has_type(m, NULL, attr_type, NETLINK_TYPE_NESTED_UNION_BY_STRING); + if (r < 0) + return r; + + policy_set_union = policy_set_get_policy_set_union( + m->containers[m->n_containers].policy_set, + attr_type); + if (!policy_set_union) + return -EOPNOTSUPP; + + m->containers[m->n_containers + 1].policy_set = + policy_set_union_get_policy_set_by_string( + policy_set_union, + key); + if (!m->containers[m->n_containers + 1].policy_set) + return -EOPNOTSUPP; + + r = sd_netlink_message_append_string(m, policy_set_union_get_match_attribute(policy_set_union), key); + if (r < 0) + return r; + + /* do we ever need non-null size */ + r = add_rtattr(m, attr_type | NLA_F_NESTED, NULL, 0); + if (r < 0) + return r; + + m->containers[m->n_containers++].offset = r; + + return 0; +} + +int sd_netlink_message_close_container(sd_netlink_message *m) { + assert_return(m, -EINVAL); + assert_return(!m->sealed, -EPERM); + assert_return(m->n_containers > 0, -EINVAL); + + m->containers[m->n_containers].policy_set = NULL; + m->containers[m->n_containers].offset = 0; + m->n_containers--; + + return 0; +} + +int sd_netlink_message_open_array(sd_netlink_message *m, uint16_t attr_type) { + int r; + + assert_return(m, -EINVAL); + assert_return(!m->sealed, -EPERM); + assert_return(m->n_containers < (NETLINK_CONTAINER_DEPTH - 1), -ERANGE); + + r = add_rtattr(m, attr_type | NLA_F_NESTED, NULL, 0); + if (r < 0) + return r; + + m->containers[m->n_containers].offset = r; + m->n_containers++; + m->containers[m->n_containers].policy_set = m->containers[m->n_containers - 1].policy_set; + + return 0; +} + +int sd_netlink_message_cancel_array(sd_netlink_message *m) { + uint32_t rta_len; + + assert_return(m, -EINVAL); + assert_return(!m->sealed, -EPERM); + assert_return(m->n_containers > 1, -EINVAL); + + rta_len = GET_CONTAINER(m, (m->n_containers - 1))->rta_len; + + for (unsigned i = 0; i < m->n_containers; i++) + GET_CONTAINER(m, i)->rta_len -= rta_len; + + m->hdr->nlmsg_len -= rta_len; + + m->n_containers--; + m->containers[m->n_containers].policy_set = NULL; + + return 0; +} + +static int netlink_message_read_internal( + sd_netlink_message *m, + uint16_t attr_type, + void **ret_data, + bool *ret_net_byteorder) { + + struct netlink_attribute *attribute; + struct rtattr *rta; + + assert_return(m, -EINVAL); + assert_return(m->sealed, -EPERM); + + assert(m->n_containers < NETLINK_CONTAINER_DEPTH); + + if (!m->containers[m->n_containers].attributes) + return -ENODATA; + + if (attr_type > m->containers[m->n_containers].max_attribute) + return -ENODATA; + + attribute = &m->containers[m->n_containers].attributes[attr_type]; + + if (attribute->offset == 0) + return -ENODATA; + + rta = (struct rtattr*)((uint8_t *) m->hdr + attribute->offset); + + if (ret_data) + *ret_data = RTA_DATA(rta); + + if (ret_net_byteorder) + *ret_net_byteorder = attribute->net_byteorder; + + return RTA_PAYLOAD(rta); +} + +int sd_netlink_message_read(sd_netlink_message *m, uint16_t attr_type, size_t size, void *data) { + void *attr_data; + int r; + + assert_return(m, -EINVAL); + + r = netlink_message_read_internal(m, attr_type, &attr_data, NULL); + if (r < 0) + return r; + + if ((size_t) r > size) + return -ENOBUFS; + + if (data) + memcpy(data, attr_data, r); + + return r; +} + +int sd_netlink_message_read_data(sd_netlink_message *m, uint16_t attr_type, size_t *ret_size, void **ret_data) { + void *attr_data; + int r; + + assert_return(m, -EINVAL); + + r = netlink_message_read_internal(m, attr_type, &attr_data, NULL); + if (r < 0) + return r; + + if (ret_data) { + void *data; + + data = memdup(attr_data, r); + if (!data) + return -ENOMEM; + + *ret_data = data; + } + + if (ret_size) + *ret_size = r; + + return r; +} + +int sd_netlink_message_read_data_suffix0(sd_netlink_message *m, uint16_t attr_type, size_t *ret_size, void **ret_data) { + void *attr_data; + int r; + + assert_return(m, -EINVAL); + + r = netlink_message_read_internal(m, attr_type, &attr_data, NULL); + if (r < 0) + return r; + + if (ret_data) { + void *data; + + data = memdup_suffix0(attr_data, r); + if (!data) + return -ENOMEM; + + *ret_data = data; + } + + if (ret_size) + *ret_size = r; + + return r; +} + +int sd_netlink_message_read_string_strdup(sd_netlink_message *m, uint16_t attr_type, char **data) { + void *attr_data; + int r; + + assert_return(m, -EINVAL); + + r = message_attribute_has_type(m, NULL, attr_type, NETLINK_TYPE_STRING); + if (r < 0) + return r; + + r = netlink_message_read_internal(m, attr_type, &attr_data, NULL); + if (r < 0) + return r; + + if (data) { + char *str; + + str = strndup(attr_data, r); + if (!str) + return -ENOMEM; + + *data = str; + } + + return 0; +} + +int sd_netlink_message_read_string(sd_netlink_message *m, uint16_t attr_type, const char **data) { + void *attr_data; + int r; + + assert_return(m, -EINVAL); + + r = message_attribute_has_type(m, NULL, attr_type, NETLINK_TYPE_STRING); + if (r < 0) + return r; + + r = netlink_message_read_internal(m, attr_type, &attr_data, NULL); + if (r < 0) + return r; + + if (strnlen(attr_data, r) >= (size_t) r) + return -EIO; + + if (data) + *data = (const char *) attr_data; + + return 0; +} + +int sd_netlink_message_read_u8(sd_netlink_message *m, uint16_t attr_type, uint8_t *data) { + void *attr_data; + int r; + + assert_return(m, -EINVAL); + + r = message_attribute_has_type(m, NULL, attr_type, NETLINK_TYPE_U8); + if (r < 0) + return r; + + r = netlink_message_read_internal(m, attr_type, &attr_data, NULL); + if (r < 0) + return r; + + if ((size_t) r < sizeof(uint8_t)) + return -EIO; + + if (data) + *data = *(uint8_t *) attr_data; + + return 0; +} + +int sd_netlink_message_read_u16(sd_netlink_message *m, uint16_t attr_type, uint16_t *data) { + void *attr_data; + bool net_byteorder; + int r; + + assert_return(m, -EINVAL); + + r = message_attribute_has_type(m, NULL, attr_type, NETLINK_TYPE_U16); + if (r < 0) + return r; + + r = netlink_message_read_internal(m, attr_type, &attr_data, &net_byteorder); + if (r < 0) + return r; + + if ((size_t) r < sizeof(uint16_t)) + return -EIO; + + if (data) { + if (net_byteorder) + *data = be16toh(*(uint16_t *) attr_data); + else + *data = *(uint16_t *) attr_data; + } + + return 0; +} + +int sd_netlink_message_read_u32(sd_netlink_message *m, uint16_t attr_type, uint32_t *data) { + void *attr_data; + bool net_byteorder; + int r; + + assert_return(m, -EINVAL); + + r = message_attribute_has_type(m, NULL, attr_type, NETLINK_TYPE_U32); + if (r < 0) + return r; + + r = netlink_message_read_internal(m, attr_type, &attr_data, &net_byteorder); + if (r < 0) + return r; + + if ((size_t) r < sizeof(uint32_t)) + return -EIO; + + if (data) { + if (net_byteorder) + *data = be32toh(*(uint32_t *) attr_data); + else + *data = *(uint32_t *) attr_data; + } + + return 0; +} + +int sd_netlink_message_read_ether_addr(sd_netlink_message *m, uint16_t attr_type, struct ether_addr *data) { + void *attr_data; + int r; + + assert_return(m, -EINVAL); + + r = message_attribute_has_type(m, NULL, attr_type, NETLINK_TYPE_ETHER_ADDR); + if (r < 0) + return r; + + r = netlink_message_read_internal(m, attr_type, &attr_data, NULL); + if (r < 0) + return r; + + if ((size_t) r < sizeof(struct ether_addr)) + return -EIO; + + if (data) + memcpy(data, attr_data, sizeof(struct ether_addr)); + + return 0; +} + +int netlink_message_read_hw_addr(sd_netlink_message *m, uint16_t attr_type, struct hw_addr_data *data) { + void *attr_data; + int r; + + assert_return(m, -EINVAL); + + r = message_attribute_has_type(m, NULL, attr_type, NETLINK_TYPE_ETHER_ADDR); + if (r < 0) + return r; + + r = netlink_message_read_internal(m, attr_type, &attr_data, NULL); + if (r < 0) + return r; + + if (r > HW_ADDR_MAX_SIZE) + return -EIO; + + if (data) { + memcpy(data->bytes, attr_data, r); + data->length = r; + } + + return 0; +} + +int sd_netlink_message_read_cache_info(sd_netlink_message *m, uint16_t attr_type, struct ifa_cacheinfo *info) { + void *attr_data; + int r; + + assert_return(m, -EINVAL); + + r = message_attribute_has_type(m, NULL, attr_type, NETLINK_TYPE_CACHE_INFO); + if (r < 0) + return r; + + r = netlink_message_read_internal(m, attr_type, &attr_data, NULL); + if (r < 0) + return r; + + if ((size_t) r < sizeof(struct ifa_cacheinfo)) + return -EIO; + + if (info) + memcpy(info, attr_data, sizeof(struct ifa_cacheinfo)); + + return 0; +} + +int netlink_message_read_in_addr_union(sd_netlink_message *m, uint16_t attr_type, int family, union in_addr_union *data) { + void *attr_data; + int r; + + assert_return(m, -EINVAL); + assert_return(IN_SET(family, AF_INET, AF_INET6), -EINVAL); + + r = message_attribute_has_type(m, NULL, attr_type, NETLINK_TYPE_IN_ADDR); + if (r < 0) + return r; + + r = netlink_message_read_internal(m, attr_type, &attr_data, NULL); + if (r < 0) + return r; + + if ((size_t) r < FAMILY_ADDRESS_SIZE(family)) + return -EIO; + + if (data) + memcpy(data, attr_data, FAMILY_ADDRESS_SIZE(family)); + + return 0; +} + +int sd_netlink_message_read_in_addr(sd_netlink_message *m, uint16_t attr_type, struct in_addr *data) { + union in_addr_union u; + int r; + + r = netlink_message_read_in_addr_union(m, attr_type, AF_INET, &u); + if (r >= 0 && data) + *data = u.in; + + return r; +} + +int sd_netlink_message_read_in6_addr(sd_netlink_message *m, uint16_t attr_type, struct in6_addr *data) { + union in_addr_union u; + int r; + + r = netlink_message_read_in_addr_union(m, attr_type, AF_INET6, &u); + if (r >= 0 && data) + *data = u.in6; + + return r; +} + +int sd_netlink_message_has_flag(sd_netlink_message *m, uint16_t attr_type) { + void *attr_data; + int r; + + assert_return(m, -EINVAL); + + /* This returns 1 when the flag is set, 0 when not set, negative errno on error. */ + + r = message_attribute_has_type(m, NULL, attr_type, NETLINK_TYPE_FLAG); + if (r < 0) + return r; + + r = netlink_message_read_internal(m, attr_type, &attr_data, NULL); + if (r == -ENODATA) + return 0; + if (r < 0) + return r; + + return 1; +} + +int sd_netlink_message_read_strv(sd_netlink_message *m, uint16_t container_type, uint16_t attr_type, char ***ret) { + _cleanup_strv_free_ char **s = NULL; + const NLAPolicySet *policy_set; + const NLAPolicy *policy; + struct rtattr *rta; + void *container; + size_t rt_len; + int r; + + assert_return(m, -EINVAL); + assert_return(m->n_containers < NETLINK_CONTAINER_DEPTH, -EINVAL); + + policy = policy_set_get_policy( + m->containers[m->n_containers].policy_set, + container_type); + if (!policy) + return -EOPNOTSUPP; + + if (policy_get_type(policy) != NETLINK_TYPE_NESTED) + return -EINVAL; + + policy_set = policy_set_get_policy_set( + m->containers[m->n_containers].policy_set, + container_type); + if (!policy_set) + return -EOPNOTSUPP; + + policy = policy_set_get_policy(policy_set, attr_type); + if (!policy) + return -EOPNOTSUPP; + + if (policy_get_type(policy) != NETLINK_TYPE_STRING) + return -EINVAL; + + r = netlink_message_read_internal(m, container_type, &container, NULL); + if (r < 0) + return r; + + rt_len = (size_t) r; + rta = container; + + /* RTA_OK() macro compares with rta->rt_len, which is unsigned short, and + * LGTM.com analysis does not like the type difference. Hence, here we + * introduce an unsigned short variable as a workaround. */ + unsigned short len = rt_len; + for (; RTA_OK(rta, len); rta = RTA_NEXT(rta, len)) { + uint16_t type; + + type = RTA_TYPE(rta); + if (type != attr_type) + continue; + + r = strv_extend(&s, RTA_DATA(rta)); + if (r < 0) + return r; + } + + *ret = TAKE_PTR(s); + return 0; +} + +static int netlink_container_parse( + sd_netlink_message *m, + struct netlink_container *container, + struct rtattr *rta, + size_t rt_len) { + + _cleanup_free_ struct netlink_attribute *attributes = NULL; + uint16_t max_attr = 0; + + /* RTA_OK() macro compares with rta->rt_len, which is unsigned short, and + * LGTM.com analysis does not like the type difference. Hence, here we + * introduce an unsigned short variable as a workaround. */ + unsigned short len = rt_len; + for (; RTA_OK(rta, len); rta = RTA_NEXT(rta, len)) { + uint16_t attr; + + attr = RTA_TYPE(rta); + max_attr = MAX(max_attr, attr); + + if (!GREEDY_REALLOC0(attributes, (size_t) max_attr + 1)) + return -ENOMEM; + + if (attributes[attr].offset != 0) + log_debug("sd-netlink: message parse - overwriting repeated attribute"); + + attributes[attr].offset = (uint8_t *) rta - (uint8_t *) m->hdr; + attributes[attr].nested = RTA_FLAGS(rta) & NLA_F_NESTED; + attributes[attr].net_byteorder = RTA_FLAGS(rta) & NLA_F_NET_BYTEORDER; + } + + container->attributes = TAKE_PTR(attributes); + container->max_attribute = max_attr; + + return 0; +} + +int sd_netlink_message_enter_container(sd_netlink_message *m, uint16_t attr_type) { + const NLAPolicy *policy; + const NLAPolicySet *policy_set; + void *container; + size_t size; + int r; + + assert_return(m, -EINVAL); + assert_return(m->n_containers < (NETLINK_CONTAINER_DEPTH - 1), -EINVAL); + + policy = policy_set_get_policy( + m->containers[m->n_containers].policy_set, + attr_type); + if (!policy) + return -EOPNOTSUPP; + + switch (policy_get_type(policy)) { + case NETLINK_TYPE_NESTED: + policy_set = policy_set_get_policy_set( + m->containers[m->n_containers].policy_set, + attr_type); + break; + + case NETLINK_TYPE_NESTED_UNION_BY_STRING: { + const NLAPolicySetUnion *policy_set_union; + const char *key; + + policy_set_union = policy_get_policy_set_union(policy); + if (!policy_set_union) + return -EOPNOTSUPP; + + r = sd_netlink_message_read_string( + m, + policy_set_union_get_match_attribute(policy_set_union), + &key); + if (r < 0) + return r; + + policy_set = policy_set_union_get_policy_set_by_string( + policy_set_union, + key); + break; + } + case NETLINK_TYPE_NESTED_UNION_BY_FAMILY: { + const NLAPolicySetUnion *policy_set_union; + int family; + + policy_set_union = policy_get_policy_set_union(policy); + if (!policy_set_union) + return -EOPNOTSUPP; + + r = sd_rtnl_message_get_family(m, &family); + if (r < 0) + return r; + + policy_set = policy_set_union_get_policy_set_by_family( + policy_set_union, + family); + break; + } + default: + assert_not_reached(); + } + if (!policy_set) + return -EOPNOTSUPP; + + r = netlink_message_read_internal(m, attr_type, &container, NULL); + if (r < 0) + return r; + + size = (size_t) r; + m->n_containers++; + + r = netlink_container_parse(m, + &m->containers[m->n_containers], + container, + size); + if (r < 0) { + m->n_containers--; + return r; + } + + m->containers[m->n_containers].policy_set = policy_set; + + return 0; +} + +int sd_netlink_message_enter_array(sd_netlink_message *m, uint16_t attr_type) { + void *container; + size_t size; + int r; + + assert_return(m, -EINVAL); + assert_return(m->n_containers < (NETLINK_CONTAINER_DEPTH - 1), -EINVAL); + + r = netlink_message_read_internal(m, attr_type, &container, NULL); + if (r < 0) + return r; + + size = (size_t) r; + m->n_containers++; + + r = netlink_container_parse(m, + &m->containers[m->n_containers], + container, + size); + if (r < 0) { + m->n_containers--; + return r; + } + + m->containers[m->n_containers].policy_set = m->containers[m->n_containers - 1].policy_set; + + return 0; +} + +int sd_netlink_message_exit_container(sd_netlink_message *m) { + assert_return(m, -EINVAL); + assert_return(m->sealed, -EINVAL); + assert_return(m->n_containers > 0, -EINVAL); + + m->containers[m->n_containers].attributes = mfree(m->containers[m->n_containers].attributes); + m->containers[m->n_containers].max_attribute = 0; + m->containers[m->n_containers].policy_set = NULL; + + m->n_containers--; + + return 0; +} + +int sd_netlink_message_get_max_attribute(sd_netlink_message *m, uint16_t *ret) { + assert_return(m, -EINVAL); + assert_return(m->sealed, -EINVAL); + assert_return(ret, -EINVAL); + + *ret = m->containers[m->n_containers].max_attribute; + return 0; +} + +int sd_netlink_message_is_error(sd_netlink_message *m) { + assert_return(m, 0); + assert_return(m->hdr, 0); + + return m->hdr->nlmsg_type == NLMSG_ERROR; +} + +int sd_netlink_message_get_errno(sd_netlink_message *m) { + struct nlmsgerr *err; + + assert_return(m, -EINVAL); + assert_return(m->hdr, -EINVAL); + + if (!sd_netlink_message_is_error(m)) + return 0; + + err = NLMSG_DATA(m->hdr); + + return err->error; +} + +static int netlink_message_parse_error(sd_netlink_message *m) { + struct nlmsgerr *err = NLMSG_DATA(m->hdr); + size_t hlen = sizeof(struct nlmsgerr); + + /* no TLVs, nothing to do here */ + if (!(m->hdr->nlmsg_flags & NLM_F_ACK_TLVS)) + return 0; + + /* if NLM_F_CAPPED is set then the inner err msg was capped */ + if (!(m->hdr->nlmsg_flags & NLM_F_CAPPED)) + hlen += err->msg.nlmsg_len - sizeof(struct nlmsghdr); + + if (m->hdr->nlmsg_len <= NLMSG_SPACE(hlen)) + return 0; + + return netlink_container_parse(m, + &m->containers[m->n_containers], + (struct rtattr*)((uint8_t*) NLMSG_DATA(m->hdr) + hlen), + NLMSG_PAYLOAD(m->hdr, hlen)); +} + +int sd_netlink_message_rewind(sd_netlink_message *m, sd_netlink *nl) { + size_t size; + int r; + + assert_return(m, -EINVAL); + assert_return(nl, -EINVAL); + + /* don't allow appending to message once parsed */ + message_seal(m); + + for (unsigned i = 1; i <= m->n_containers; i++) + m->containers[i].attributes = mfree(m->containers[i].attributes); + + m->n_containers = 0; + + if (m->containers[0].attributes) + /* top-level attributes have already been parsed */ + return 0; + + assert(m->hdr); + + r = netlink_get_policy_set_and_header_size(nl, m->hdr->nlmsg_type, + &m->containers[0].policy_set, &size); + if (r < 0) + return r; + + if (sd_netlink_message_is_error(m)) + return netlink_message_parse_error(m); + + return netlink_container_parse(m, + &m->containers[0], + (struct rtattr*)((uint8_t*) NLMSG_DATA(m->hdr) + NLMSG_ALIGN(size)), + NLMSG_PAYLOAD(m->hdr, size)); +} + +void message_seal(sd_netlink_message *m) { + assert(m); + + m->sealed = true; +} + +sd_netlink_message *sd_netlink_message_next(sd_netlink_message *m) { + assert_return(m, NULL); + + return m->next; +} |