int message_new(sd_netlink *rtnl, sd_netlink_message **ret, uint16_t type) {
_cleanup_netlink_message_unref_ sd_netlink_message *m = NULL;
const NLType *nl_type;
size_t size;
int r;
r = type_system_get_type(&type_system_root, &nl_type, type);
if (r < 0)
return r;
if (type_get_type(nl_type) != NETLINK_TYPE_NESTED)
return -EINVAL;
r = message_new_empty(rtnl, &m);
if (r < 0)
return r;
size = NLMSG_SPACE(type_get_size(nl_type));
assert(size >= sizeof(struct nlmsghdr));
m->hdr = malloc0(size);
if (!m->hdr)
return -ENOMEM;
m->hdr->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
type_get_type_system(nl_type, &m->containers[0].type_system);
m->hdr->nlmsg_len = size;
m->hdr->nlmsg_type = type;
*ret = m;
m = NULL;
return 0;
}
int message_new(sd_rtnl *rtnl, sd_rtnl_message **ret, uint16_t type) {
_cleanup_rtnl_message_unref_ sd_rtnl_message *m = NULL;
const NLType *nl_type;
size_t size;
int r;
r = type_system_get_type(NULL, &nl_type, type);
if (r < 0)
return r;
assert(nl_type->type == NLA_NESTED);
r = message_new_empty(rtnl, &m);
if (r < 0)
return r;
size = NLMSG_SPACE(nl_type->size);
assert(size >= sizeof(struct nlmsghdr));
m->hdr = malloc0(size);
if (!m->hdr)
return -ENOMEM;
m->hdr->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
m->container_type_system[0] = nl_type->type_system;
m->hdr->nlmsg_len = size;
m->hdr->nlmsg_type = type;
*ret = m;
m = NULL;
return 0;
}
static int genl_message_new(sd_netlink *nl, sd_genl_family family, uint16_t nlmsg_type, uint8_t cmd, sd_netlink_message **ret) {
int r;
struct genlmsghdr *genl;
const NLType *genl_cmd_type, *nl_type;
const NLTypeSystem *type_system;
size_t size;
_cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL;
assert_return(nl->protocol == NETLINK_GENERIC, -EINVAL);
r = type_system_get_type(&genl_family_type_system_root, &genl_cmd_type, family);
if (r < 0)
return r;
r = message_new_empty(nl, &m);
if (r < 0)
return r;
size = NLMSG_SPACE(sizeof(struct genlmsghdr));
m->hdr = malloc0(size);
if (!m->hdr)
return -ENOMEM;
m->hdr->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
type_get_type_system(genl_cmd_type, &type_system);
r = type_system_get_type(type_system, &nl_type, cmd);
if (r < 0)
return r;
m->hdr->nlmsg_len = size;
m->hdr->nlmsg_type = nlmsg_type;
type_get_type_system(nl_type, &m->containers[0].type_system);
genl = NLMSG_DATA(m->hdr);
genl->cmd = cmd;
genl->version = genl_families[family].version;
*ret = TAKE_PTR(m);
return 0;
}
static int message_attribute_has_type(sd_rtnl_message *m, uint16_t attribute_type, uint16_t data_type) {
const NLType *type;
int r;
r = type_system_get_type(m->container_type_system[m->n_containers], &type, attribute_type);
if (r < 0)
return r;
if (type->type != data_type)
return -EINVAL;
return type->size;
}
int sd_rtnl_message_rewind(sd_rtnl_message *m) {
const NLType *type;
unsigned i;
int r;
assert_return(m, -EINVAL);
/* don't allow appending to message once parsed */
if (!m->sealed)
rtnl_message_seal(m);
for (i = 1; i <= m->n_containers; i++) {
free(m->rta_offset_tb[i]);
m->rta_offset_tb[i] = NULL;
m->rta_tb_size[i] = 0;
m->container_type_system[i] = NULL;
}
m->n_containers = 0;
if (m->rta_offset_tb[0]) {
/* top-level attributes have already been parsed */
return 0;
}
assert(m->hdr);
r = type_system_get_type(NULL, &type, m->hdr->nlmsg_type);
if (r < 0)
return r;
if (type->type == NLA_NESTED) {
const NLTypeSystem *type_system = type->type_system;
assert(type_system);
m->container_type_system[0] = type_system;
r = rtnl_message_parse(m,
&m->rta_offset_tb[m->n_containers],
&m->rta_tb_size[m->n_containers],
type_system->max,
(struct rtattr*)((uint8_t*)NLMSG_DATA(m->hdr) +
NLMSG_ALIGN(type->size)),
NLMSG_PAYLOAD(m->hdr, type->size));
if (r < 0)
return r;
}
return 0;
}
int sd_netlink_message_rewind(sd_netlink_message *m) {
const NLType *nl_type;
uint16_t type;
size_t size;
unsigned i;
int r;
assert_return(m, -EINVAL);
/* don't allow appending to message once parsed */
if (!m->sealed)
rtnl_message_seal(m);
for (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 = type_system_get_type(&type_system_root, &nl_type, m->hdr->nlmsg_type);
if (r < 0)
return r;
type = type_get_type(nl_type);
size = type_get_size(nl_type);
if (type == NETLINK_TYPE_NESTED) {
const NLTypeSystem *type_system;
type_get_type_system(nl_type, &type_system);
m->containers[0].type_system = type_system;
r = netlink_container_parse(m,
&m->containers[m->n_containers],
type_system_get_count(type_system),
(struct rtattr*)((uint8_t*)NLMSG_DATA(m->hdr) + NLMSG_ALIGN(size)),
NLMSG_PAYLOAD(m->hdr, size));
if (r < 0)
return r;
}
return 0;
}
int type_system_get_type_system_union(const NLTypeSystem *type_system, const NLTypeSystemUnion **ret, uint16_t type) {
const NLType *nl_type;
int r;
assert(ret);
r = type_system_get_type(type_system, &nl_type, type);
if (r < 0)
return r;
assert(nl_type->type == NLA_UNION);
assert(nl_type->type_system_union);
*ret = nl_type->type_system_union;
return 0;
}
int type_system_get_type_system(const NLTypeSystem *type_system, const NLTypeSystem **ret, uint16_t type) {
const NLType *nl_type;
int r;
assert(ret);
r = type_system_get_type(type_system, &nl_type, type);
if (r < 0)
return r;
assert(nl_type->type == NLA_NESTED);
assert(nl_type->type_system);
*ret = nl_type->type_system;
return 0;
}
static int message_attribute_has_type(sd_netlink_message *m, size_t *out_size, uint16_t attribute_type, uint16_t data_type) {
const NLType *type;
int r;
assert(m);
r = type_system_get_type(m->containers[m->n_containers].type_system, &type, attribute_type);
if (r < 0)
return r;
if (type_get_type(type) != data_type)
return -EINVAL;
if (out_size)
*out_size = type_get_size(type);
return 0;
}
int sd_netlink_message_enter_container(sd_netlink_message *m, unsigned short type_id) {
const NLType *nl_type;
const NLTypeSystem *type_system;
void *container;
uint16_t type;
size_t size;
int r;
assert_return(m, -EINVAL);
assert_return(m->n_containers < RTNL_CONTAINER_DEPTH, -EINVAL);
r = type_system_get_type(m->containers[m->n_containers].type_system,
&nl_type,
type_id);
if (r < 0)
return r;
type = type_get_type(nl_type);
if (type == NETLINK_TYPE_NESTED) {
r = type_system_get_type_system(m->containers[m->n_containers].type_system,
&type_system,
type_id);
if (r < 0)
return r;
} else if (type == NETLINK_TYPE_UNION) {
const NLTypeSystemUnion *type_system_union;
r = type_system_get_type_system_union(m->containers[m->n_containers].type_system,
&type_system_union,
type_id);
if (r < 0)
return r;
switch (type_system_union->match_type) {
case NL_MATCH_SIBLING:
{
const char *key;
r = sd_netlink_message_read_string(m, type_system_union->match, &key);
if (r < 0)
return r;
r = type_system_union_get_type_system(type_system_union,
&type_system,
key);
if (r < 0)
return r;
break;
}
case NL_MATCH_PROTOCOL:
{
int family;
r = sd_rtnl_message_get_family(m, &family);
if (r < 0)
return r;
r = type_system_union_protocol_get_type_system(type_system_union,
&type_system,
family);
if (r < 0)
return r;
break;
}
default:
assert_not_reached("sd-netlink: invalid type system union type");
}
} else
return -EINVAL;
r = netlink_message_read_internal(m, type_id, &container, NULL);
if (r < 0)
return r;
else
size = (size_t)r;
m->n_containers ++;
r = netlink_container_parse(m,
&m->containers[m->n_containers],
type_system_get_count(type_system),
container,
size);
if (r < 0) {
m->n_containers --;
return r;
}
m->containers[m->n_containers].type_system = type_system;
return 0;
}
int sd_rtnl_message_enter_container(sd_rtnl_message *m, unsigned short type) {
const NLType *nl_type;
const NLTypeSystem *type_system;
void *container;
size_t size;
int r;
assert_return(m, -EINVAL);
assert_return(m->n_containers < RTNL_CONTAINER_DEPTH, -EINVAL);
r = type_system_get_type(m->container_type_system[m->n_containers],
&nl_type,
type);
if (r < 0)
return r;
if (nl_type->type == NLA_NESTED) {
r = type_system_get_type_system(m->container_type_system[m->n_containers],
&type_system,
type);
if (r < 0)
return r;
} else if (nl_type->type == NLA_UNION) {
const NLTypeSystemUnion *type_system_union;
const char *key;
r = type_system_get_type_system_union(m->container_type_system[m->n_containers],
&type_system_union,
type);
if (r < 0)
return r;
r = sd_rtnl_message_read_string(m, type_system_union->match, &key);
if (r < 0)
return r;
r = type_system_union_get_type_system(type_system_union,
&type_system,
key);
if (r < 0)
return r;
} else
return -EINVAL;
r = rtnl_message_read_internal(m, type, &container);
if (r < 0)
return r;
else
size = (size_t)r;
m->n_containers ++;
r = rtnl_message_parse(m,
&m->rta_offset_tb[m->n_containers],
&m->rta_tb_size[m->n_containers],
type_system->max,
container,
size);
if (r < 0) {
m->n_containers --;
return r;
}
m->container_type_system[m->n_containers] = type_system;
return 0;
}
/* returns the number of bytes sent, or a negative error code */
int socket_write_message(sd_rtnl *nl, sd_rtnl_message *m) {
union {
struct sockaddr sa;
struct sockaddr_nl nl;
} addr = {
.nl.nl_family = AF_NETLINK,
};
ssize_t k;
assert(nl);
assert(m);
assert(m->hdr);
k = sendto(nl->fd, m->hdr, m->hdr->nlmsg_len,
0, &addr.sa, sizeof(addr));
if (k < 0)
return (errno == EAGAIN) ? 0 : -errno;
return k;
}
static int socket_recv_message(int fd, struct iovec *iov, uint32_t *_group, bool peek) {
uint8_t cred_buffer[CMSG_SPACE(sizeof(struct ucred)) +
CMSG_SPACE(sizeof(struct nl_pktinfo))];
struct msghdr msg = {
.msg_iov = iov,
.msg_iovlen = 1,
.msg_control = cred_buffer,
.msg_controllen = sizeof(cred_buffer),
};
struct cmsghdr *cmsg;
uint32_t group = 0;
bool auth = false;
int r;
assert(fd >= 0);
assert(iov);
r = recvmsg(fd, &msg, MSG_TRUNC | (peek ? MSG_PEEK : 0));
if (r < 0) {
/* no data */
if (errno == ENOBUFS)
log_debug("rtnl: kernel receive buffer overrun");
return (errno == EAGAIN) ? 0 : -errno;
} else if (r == 0)
/* connection was closed by the kernel */
return -ECONNRESET;
for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
if (cmsg->cmsg_level == SOL_SOCKET &&
cmsg->cmsg_type == SCM_CREDENTIALS &&
cmsg->cmsg_len == CMSG_LEN(sizeof(struct ucred))) {
struct ucred *ucred = (void *)CMSG_DATA(cmsg);
/* from the kernel */
if (ucred->uid == 0 && ucred->pid == 0)
auth = true;
} else if (cmsg->cmsg_level == SOL_NETLINK &&
cmsg->cmsg_type == NETLINK_PKTINFO &&
cmsg->cmsg_len == CMSG_LEN(sizeof(struct nl_pktinfo))) {
struct nl_pktinfo *pktinfo = (void *)CMSG_DATA(cmsg);
/* multi-cast group */
group = pktinfo->group;
}
}
if (!auth)
/* not from the kernel, ignore */
return 0;
if (group)
*_group = group;
return r;
}
/* On success, the number of bytes received is returned and *ret points to the received message
* which has a valid header and the correct size.
* If nothing useful was received 0 is returned.
* On failure, a negative error code is returned.
*/
int socket_read_message(sd_rtnl *rtnl) {
_cleanup_rtnl_message_unref_ sd_rtnl_message *first = NULL;
struct iovec iov = {};
uint32_t group = 0;
bool multi_part = false, done = false;
struct nlmsghdr *new_msg;
size_t len;
int r;
unsigned i = 0;
assert(rtnl);
assert(rtnl->rbuffer);
assert(rtnl->rbuffer_allocated >= sizeof(struct nlmsghdr));
/* read nothing, just get the pending message size */
r = socket_recv_message(rtnl->fd, &iov, &group, true);
if (r <= 0)
return r;
else
len = (size_t)r;
/* make room for the pending message */
if (!greedy_realloc((void **)&rtnl->rbuffer,
&rtnl->rbuffer_allocated,
len, sizeof(uint8_t)))
return -ENOMEM;
iov.iov_base = rtnl->rbuffer;
iov.iov_len = rtnl->rbuffer_allocated;
/* read the pending message */
r = socket_recv_message(rtnl->fd, &iov, &group, false);
if (r <= 0)
return r;
else
len = (size_t)r;
if (len > rtnl->rbuffer_allocated)
/* message did not fit in read buffer */
return -EIO;
if (NLMSG_OK(rtnl->rbuffer, len) && rtnl->rbuffer->nlmsg_flags & NLM_F_MULTI) {
multi_part = true;
for (i = 0; i < rtnl->rqueue_partial_size; i++) {
if (rtnl_message_get_serial(rtnl->rqueue_partial[i]) ==
rtnl->rbuffer->nlmsg_seq) {
first = rtnl->rqueue_partial[i];
break;
}
}
}
for (new_msg = rtnl->rbuffer; NLMSG_OK(new_msg, len); new_msg = NLMSG_NEXT(new_msg, len)) {
_cleanup_rtnl_message_unref_ sd_rtnl_message *m = NULL;
const NLType *nl_type;
if (!group && new_msg->nlmsg_pid != rtnl->sockaddr.nl.nl_pid)
/* not broadcast and not for us */
continue;
if (new_msg->nlmsg_type == NLMSG_NOOP)
/* silently drop noop messages */
continue;
if (new_msg->nlmsg_type == NLMSG_DONE) {
/* finished reading multi-part message */
done = true;
break;
}
/* check that we support this message type */
r = type_system_get_type(NULL, &nl_type, new_msg->nlmsg_type);
if (r < 0) {
if (r == -ENOTSUP)
log_debug("sd-rtnl: ignored message with unknown type: %u",
new_msg->nlmsg_type);
continue;
}
/* check that the size matches the message type */
if (new_msg->nlmsg_len < NLMSG_LENGTH(nl_type->size))
continue;
r = message_new_empty(rtnl, &m);
if (r < 0)
return r;
m->hdr = memdup(new_msg, new_msg->nlmsg_len);
if (!m->hdr)
return -ENOMEM;
/* seal and parse the top-level message */
r = sd_rtnl_message_rewind(m);
if (r < 0)
return r;
/* push the message onto the multi-part message stack */
if (first)
m->next = first;
first = m;
m = NULL;
}
if (len)
log_debug("sd-rtnl: discarding %zu bytes of incoming message", len);
if (!first)
return 0;
if (!multi_part || done) {
/* we got a complete message, push it on the read queue */
r = rtnl_rqueue_make_room(rtnl);
if (r < 0)
return r;
rtnl->rqueue[rtnl->rqueue_size ++] = first;
first = NULL;
if (multi_part && (i < rtnl->rqueue_partial_size)) {
/* remove the message form the partial read queue */
memmove(rtnl->rqueue_partial + i,rtnl->rqueue_partial + i + 1,
sizeof(sd_rtnl_message*) * (rtnl->rqueue_partial_size - i - 1));
rtnl->rqueue_partial_size --;
}
return 1;
} else {
/* we only got a partial multi-part message, push it on the
partial read queue */
if (i < rtnl->rqueue_partial_size) {
rtnl->rqueue_partial[i] = first;
} else {
r = rtnl_rqueue_partial_make_room(rtnl);
if (r < 0)
return r;
rtnl->rqueue_partial[rtnl->rqueue_partial_size ++] = first;
}
first = NULL;
return 0;
}
}
