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Merged
jk-ozlabs merged 1 commit into from
Feb 23, 2026
Merged

mctpd: Add VendorDefinedMessageTypes property #136

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14 changes: 10 additions & 4 deletions src/mctp-control-spec.h
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Original file line number Diff line number Diff line change
Expand Up @@ -114,14 +114,20 @@ struct mctp_ctrl_resp_get_vdm_support {
uint8_t completion_code;
uint8_t vendor_id_set_selector;
uint8_t vendor_id_format;
union {
uint16_t vendor_id_data_pcie;
uint32_t vendor_id_data_iana;
};
/* following bytes are dependent on vendor id format
* and shall be interpreted by appropriate binding handler */
} __attribute__((__packed__));

struct mctp_vdm_pcie_data {
uint16_t vendor_id;
uint16_t cmd_set;
} __attribute__((__packed__));

struct mctp_vdm_iana_data {
uint32_t enterprise_number;
uint16_t cmd_set;
} __attribute__((__packed__));

struct mctp_pci_ctrl_resp_get_vdm_support {
struct mctp_ctrl_msg_hdr ctrl_hdr;
uint8_t completion_code;
Expand Down
205 changes: 194 additions & 11 deletions src/mctpd.c
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Original file line number Diff line number Diff line change
Expand Up @@ -148,6 +148,8 @@ struct link {
struct ctx *ctx;
};

struct vdm_type_support;

struct peer {
uint32_t net;
mctp_eid_t eid;
Expand Down Expand Up @@ -185,6 +187,9 @@ struct peer {
uint8_t *message_types;
size_t num_message_types;

struct vdm_type_support *vdm_types;
size_t num_vdm_types;

// From Get Endpoint ID
uint8_t endpoint_type;
uint8_t medium_spec;
Expand Down Expand Up @@ -1060,8 +1065,9 @@ handle_control_get_vdm_type_support(struct ctx *ctx, int sd,
struct mctp_ctrl_resp_get_vdm_support *resp = NULL;
struct mctp_ctrl_cmd_get_vdm_support *req = NULL;
size_t resp_len, max_rsp_len, vdm_count;
struct mctp_vdm_pcie_data *vdm_pcie;
struct mctp_vdm_iana_data *vdm_iana;
struct vdm_type_support *cur_vdm;
uint16_t *cmd_type_ptr;
uint8_t *resp_buf;
int rc;

Expand All @@ -1073,15 +1079,14 @@ handle_control_get_vdm_type_support(struct ctx *ctx, int sd,
req = (void *)buf;
vdm_count = ctx->num_supported_vdm_types;
// Allocate space for 32 bit VID + 16 bit cmd set
max_rsp_len = sizeof(*resp) + sizeof(uint16_t);
max_rsp_len = sizeof(*resp) + sizeof(struct mctp_vdm_iana_data);
resp_len = max_rsp_len;
resp_buf = malloc(max_rsp_len);
if (!resp_buf) {
warnx("Failed to allocate response buffer");
return -ENOMEM;
}
resp = (void *)resp_buf;
cmd_type_ptr = (uint16_t *)(resp + 1);
mctp_ctrl_msg_hdr_init_resp(&resp->ctrl_hdr, req->ctrl_hdr);

if (req->vendor_id_set_selector >= vdm_count) {
Expand All @@ -1103,17 +1108,17 @@ handle_control_get_vdm_type_support(struct ctx *ctx, int sd,
resp->vendor_id_format = cur_vdm->format;

if (cur_vdm->format == VID_FORMAT_PCIE) {
// 4 bytes was reserved for VID, but PCIe VID uses only 2 bytes.
cmd_type_ptr--;
resp_len = max_rsp_len - sizeof(uint16_t);
resp->vendor_id_data_pcie =
htobe16(cur_vdm->vendor_id.pcie);
vdm_pcie = (void *)(resp + 1);
resp_len = sizeof(*resp) +
sizeof(struct mctp_vdm_pcie_data);
vdm_pcie->vendor_id = htobe16(cur_vdm->vendor_id.pcie);
vdm_pcie->cmd_set = htobe16(cur_vdm->cmd_set);
} else {
resp->vendor_id_data_iana =
vdm_iana = (void *)(resp + 1);
vdm_iana->enterprise_number =
htobe32(cur_vdm->vendor_id.iana);
vdm_iana->cmd_set = htobe16(cur_vdm->cmd_set);
}

*cmd_type_ptr = htobe16(cur_vdm->cmd_set);
}

rc = reply_message(ctx, sd, resp, resp_len, addr);
Expand Down Expand Up @@ -2085,6 +2090,7 @@ static int remove_peer(struct peer *peer)

n->peers[peer->eid] = NULL;
free(peer->message_types);
free(peer->vdm_types);
free(peer->uuid);

for (idx = 0; idx < ctx->num_peers; idx++) {
Expand Down Expand Up @@ -2127,6 +2133,7 @@ static void free_peers(struct ctx *ctx)
for (size_t i = 0; i < ctx->num_peers; i++) {
struct peer *peer = ctx->peers[i];
free(peer->message_types);
free(peer->vdm_types);
free(peer->uuid);
free(peer->path);
free(peer->bridge_ep_poll.sources);
Expand Down Expand Up @@ -2585,6 +2592,106 @@ static int query_get_peer_msgtypes(struct peer *peer)
return rc;
}

static int query_get_peer_vdm_types(struct peer *peer)
{
struct vdm_type_support *cur_vdm_type, *new_vdm, *vdm_types = NULL;
size_t buf_size, expect_size, new_size, num_vdm_types = 0;
struct mctp_ctrl_resp_get_vdm_support *resp = NULL;
struct mctp_ctrl_cmd_get_vdm_support req;
struct mctp_vdm_pcie_data *vdm_pcie;
struct mctp_vdm_iana_data *vdm_iana;
struct sockaddr_mctp_ext addr;
uint8_t iid, fmt, *buf = NULL;
int rc;

req.ctrl_hdr.command_code = MCTP_CTRL_CMD_GET_VENDOR_MESSAGE_SUPPORT;
req.vendor_id_set_selector = 0;

while (true) {
iid = mctp_next_iid(peer->ctx);

mctp_ctrl_msg_hdr_init_req(
&req.ctrl_hdr, iid,
MCTP_CTRL_CMD_GET_VENDOR_MESSAGE_SUPPORT);
if (buf) {
free(buf);
buf = NULL;
}
rc = endpoint_query_peer(peer, MCTP_CTRL_HDR_MSG_TYPE, &req,
sizeof(req), &buf, &buf_size, &addr);
if (rc < 0)
break;

expect_size = sizeof(*resp);
rc = mctp_ctrl_validate_response(
buf, buf_size, expect_size, peer_tostr_short(peer), iid,
MCTP_CTRL_CMD_GET_VENDOR_MESSAGE_SUPPORT);
if (rc)
break;

resp = (void *)buf;
fmt = resp->vendor_id_format;
if (fmt == MCTP_GET_VDM_SUPPORT_PCIE_FORMAT_ID) {
expect_size = sizeof(*resp) +
sizeof(struct mctp_vdm_pcie_data);
} else if (fmt == MCTP_GET_VDM_SUPPORT_IANA_FORMAT_ID) {
expect_size = sizeof(*resp) +
sizeof(struct mctp_vdm_iana_data);
} else {
warnx("%s: bad vendor_id_format 0x%02x dest %s",
__func__, fmt, peer_tostr(peer));
rc = -ENOMSG;
break;
}
if (buf_size != expect_size) {
warnx("%s: bad reply length. got %zu, expected %zu dest %s",
__func__, buf_size, expect_size,
peer_tostr(peer));
rc = -ENOMSG;
break;
}

new_size =
(num_vdm_types + 1) * sizeof(struct vdm_type_support);
new_vdm = realloc(vdm_types, new_size);
if (!new_vdm) {
rc = -ENOMEM;
break;
}
vdm_types = new_vdm;
cur_vdm_type = vdm_types + num_vdm_types;
cur_vdm_type->format = fmt;

if (fmt == MCTP_GET_VDM_SUPPORT_IANA_FORMAT_ID) {
vdm_iana = (struct mctp_vdm_iana_data *)(resp + 1);
cur_vdm_type->vendor_id.iana =
be32toh(vdm_iana->enterprise_number);
cur_vdm_type->cmd_set = be16toh(vdm_iana->cmd_set);
} else {
vdm_pcie = (struct mctp_vdm_pcie_data *)(resp + 1);
cur_vdm_type->vendor_id.pcie =
be16toh(vdm_pcie->vendor_id);
cur_vdm_type->cmd_set = be16toh(vdm_pcie->cmd_set);
}
num_vdm_types++;
if (resp->vendor_id_set_selector ==
MCTP_GET_VDM_SUPPORT_NO_MORE_CAP_SET) {
peer->vdm_types = vdm_types;
vdm_types = NULL;
peer->num_vdm_types = num_vdm_types;
rc = 0;
break;
}
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@jk-ozlabs jk-ozlabs Feb 23, 2026

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We have a remote memory exhaustion problem here: the remote endpoint could return the same set selector repeatedly, causing an infinite allocation of vdm_types.

I have a fix in progress, will merge along with this.

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@msnidhin msnidhin Feb 23, 2026

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We have a remote memory exhaustion problem here: the remote endpoint could return the same set selector repeatedly, causing an infinite allocation of vdm_types.

I have a fix in progress, will merge along with this.

Thank You for merging and fixing the issue !!


/* Use the next selector from the response. 0xFF indicates no more entries */
req.vendor_id_set_selector = resp->vendor_id_set_selector;
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@jk-ozlabs jk-ozlabs Jan 15, 2026

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Might be cleaner to do the 0xff check here, and rc = 0; break if it matches. Then your while loop can be unconditional, and the error cases can just break, rather than needing a goto between scopes.

}

free(buf);
free(vdm_types);
return rc;
}

static int peer_set_uuid(struct peer *peer, const uint8_t uuid[16])
{
if (!peer->uuid) {
Expand Down Expand Up @@ -3019,6 +3126,7 @@ static int method_learn_endpoint(sd_bus_message *call, void *data,
static int query_peer_properties(struct peer *peer)
{
const unsigned int max_retries = 4;
bool supports_vdm = false;
int rc;

for (unsigned int i = 0; i < max_retries; i++) {
Expand Down Expand Up @@ -3047,6 +3155,41 @@ static int query_peer_properties(struct peer *peer)
}
}

for (unsigned int i = 0; i < peer->num_message_types; i++) {
if (peer->message_types[i] ==
MCTP_GET_VDM_SUPPORT_IANA_FORMAT_ID ||
peer->message_types[i] ==
MCTP_GET_VDM_SUPPORT_PCIE_FORMAT_ID) {
supports_vdm = true;
break;
}
}

if (supports_vdm) {
for (unsigned int i = 0; i < max_retries; i++) {
rc = query_get_peer_vdm_types(peer);

if (rc == 0)
break;

// On timeout, retry
if (rc == -ETIMEDOUT) {
if (peer->ctx->verbose)
warnx("Retrying to get vendor message types for %s. Attempt %u",
peer_tostr(peer), i + 1);
rc = 0;
continue;
}

if (rc < 0) {
warnx("Error getting vendor message types for %s. Ignoring error %d %s",
peer_tostr(peer), rc, strerror(-rc));
rc = 0;
break;
}
}
}

for (unsigned int i = 0; i < max_retries; i++) {
rc = query_get_peer_uuid(peer);

Expand Down Expand Up @@ -3939,6 +4082,41 @@ static int bus_endpoint_get_prop(sd_bus *bus, const char *path,
rc = sd_bus_message_append_array(reply, 'y',
peer->message_types,
peer->num_message_types);
} else if (strcmp(property, "VendorDefinedMessageTypes") == 0) {
rc = sd_bus_message_open_container(reply, 'a', "(yvq)");
if (rc < 0)
return rc;

for (size_t i = 0; i < peer->num_vdm_types; i++) {
struct vdm_type_support *vdm = &peer->vdm_types[i];
rc = sd_bus_message_open_container(reply, 'r', "yvq");
if (rc < 0)
return rc;

rc = sd_bus_message_append(reply, "y", vdm->format);
if (rc < 0)
return rc;

if (vdm->format == VID_FORMAT_PCIE) {
rc = sd_bus_message_append(reply, "v", "q",
vdm->vendor_id.pcie);
} else {
rc = sd_bus_message_append(reply, "v", "u",
vdm->vendor_id.iana);
}
if (rc < 0)
return rc;

rc = sd_bus_message_append(reply, "q", vdm->cmd_set);
if (rc < 0)
return rc;

rc = sd_bus_message_close_container(reply);
if (rc < 0)
return rc;
}

rc = sd_bus_message_close_container(reply);
} else if (strcmp(property, "UUID") == 0 && peer->uuid) {
const char *s = dfree(bytes_to_uuid(peer->uuid));
rc = sd_bus_message_append(reply, "s", s);
Expand Down Expand Up @@ -4128,6 +4306,11 @@ static const sd_bus_vtable bus_endpoint_obmc_vtable[] = {
bus_endpoint_get_prop,
0,
SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("VendorDefinedMessageTypes",
"a(yvq)",
bus_endpoint_get_prop,
0,
SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_VTABLE_END
};

Expand Down
24 changes: 23 additions & 1 deletion tests/mctpenv/__init__.py
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Original file line number Diff line number Diff line change
Expand Up @@ -348,12 +348,15 @@ def to_buf(self):


class Endpoint:
def __init__(self, iface, lladdr, ep_uuid=None, eid=0, types=None):
def __init__(
self, iface, lladdr, ep_uuid=None, eid=0, types=None, vdm_msg_types=None
):
self.iface = iface
self.lladdr = lladdr
self.uuid = ep_uuid or uuid.uuid1()
self.eid = eid
self.types = types or [0]
self.vdm_msg_types = vdm_msg_types or []
self.bridged_eps = []
self.allocated_pool = None # or (start, size)

Expand Down Expand Up @@ -428,6 +431,25 @@ async def handle_mctp_control(self, sock, addr, data):
data = bytes(hdr + [0x00, len(types)] + types)
await sock.send(raddr, data)

elif opcode == 6:
# Get Vendor Defined Message Support
vdm_support = self.vdm_msg_types
selector = data[2]
if selector >= len(vdm_support):
await sock.send(raddr, bytes(hdr + [0x02]))
return
vdm_format, vendor_id, cmd_set = vdm_support[selector]
next_selector = (
0xFF if selector == (len(vdm_support) - 1) else selector + 1
)
resp = bytes(hdr + [0x00, next_selector, vdm_format])
if vdm_format == 0:
resp += vendor_id.to_bytes(2, 'big')
elif vdm_format == 1:
resp += vendor_id.to_bytes(4, 'big')
resp += cmd_set.to_bytes(2, 'big')
await sock.send(raddr, resp)

elif opcode == 8:
# Allocate Endpoint IDs
(_, _, _, pool_size, pool_start) = data
Expand Down
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