blob: 741082d2ac6aca857630f3bd9f6db25a9b54f478 [file] [log] [blame]
/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
#include <assert.h>
#include <errno.h>
#include <stdarg.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#undef pr_fmt
#define pr_fmt(fmt) "core: " fmt
#include "libmctp.h"
#include "libmctp-alloc.h"
#include "libmctp-log.h"
#include "libmctp-cmds.h"
#include "range.h"
/* Internal data structures */
enum mctp_bus_state {
mctp_bus_state_constructed = 0,
mctp_bus_state_tx_enabled,
mctp_bus_state_tx_disabled,
};
struct mctp_bus {
mctp_eid_t eid;
struct mctp_binding *binding;
enum mctp_bus_state state;
struct mctp_pktbuf *tx_queue_head;
struct mctp_pktbuf *tx_queue_tail;
/* todo: routing */
};
struct mctp_msg_ctx {
uint8_t src;
uint8_t dest;
uint8_t tag;
uint8_t last_seq;
void *buf;
size_t buf_size;
size_t buf_alloc_size;
size_t fragment_size;
};
struct mctp {
int n_busses;
struct mctp_bus *busses;
/* Message RX callback */
mctp_rx_fn message_rx;
void *message_rx_data;
/* Packet capture callback */
mctp_capture_fn capture;
void *capture_data;
/* Message reassembly.
* @todo: flexible context count
*/
struct mctp_msg_ctx msg_ctxs[16];
enum {
ROUTE_ENDPOINT,
ROUTE_BRIDGE,
} route_policy;
size_t max_message_size;
};
#ifndef BUILD_ASSERT
#define BUILD_ASSERT(x) \
do { \
(void)sizeof(char[0 - (!(x))]); \
} while (0)
#endif
#ifndef ARRAY_SIZE
#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
#endif
/* 64kb should be sufficient for a single message. Applications
* requiring higher sizes can override by setting max_message_size.*/
#ifndef MCTP_MAX_MESSAGE_SIZE
#define MCTP_MAX_MESSAGE_SIZE 65536
#endif
static int mctp_message_tx_on_bus(struct mctp_bus *bus, mctp_eid_t src,
mctp_eid_t dest, bool tag_owner,
uint8_t msg_tag, void *msg, size_t msg_len);
struct mctp_pktbuf *mctp_pktbuf_alloc(struct mctp_binding *binding, size_t len)
{
struct mctp_pktbuf *buf;
size_t size;
size = binding->pkt_size + binding->pkt_header + binding->pkt_trailer;
/* todo: pools */
buf = __mctp_alloc(sizeof(*buf) + size);
if (!buf)
return NULL;
buf->size = size;
buf->start = binding->pkt_header;
buf->end = buf->start + len;
buf->mctp_hdr_off = buf->start;
buf->next = NULL;
return buf;
}
void mctp_pktbuf_free(struct mctp_pktbuf *pkt)
{
__mctp_free(pkt);
}
struct mctp_hdr *mctp_pktbuf_hdr(struct mctp_pktbuf *pkt)
{
return (struct mctp_hdr *)(pkt->data + pkt->mctp_hdr_off);
}
void *mctp_pktbuf_data(struct mctp_pktbuf *pkt)
{
return pkt->data + pkt->mctp_hdr_off + sizeof(struct mctp_hdr);
}
size_t mctp_pktbuf_size(struct mctp_pktbuf *pkt)
{
return pkt->end - pkt->start;
}
void *mctp_pktbuf_alloc_start(struct mctp_pktbuf *pkt, size_t size)
{
assert(size <= pkt->start);
pkt->start -= size;
return pkt->data + pkt->start;
}
void *mctp_pktbuf_alloc_end(struct mctp_pktbuf *pkt, size_t size)
{
void *buf;
assert(size <= (pkt->size - pkt->end));
buf = pkt->data + pkt->end;
pkt->end += size;
return buf;
}
int mctp_pktbuf_push(struct mctp_pktbuf *pkt, void *data, size_t len)
{
void *p;
if (pkt->end + len > pkt->size)
return -1;
p = pkt->data + pkt->end;
pkt->end += len;
memcpy(p, data, len);
return 0;
}
void *mctp_pktbuf_pop(struct mctp_pktbuf *pkt, size_t len)
{
if (len > mctp_pktbuf_size(pkt))
return NULL;
pkt->end -= len;
return pkt->data + pkt->end;
}
/* Message reassembly */
static struct mctp_msg_ctx *mctp_msg_ctx_lookup(struct mctp *mctp, uint8_t src,
uint8_t dest, uint8_t tag)
{
unsigned int i;
/* @todo: better lookup, if we add support for more outstanding
* message contexts */
for (i = 0; i < ARRAY_SIZE(mctp->msg_ctxs); i++) {
struct mctp_msg_ctx *ctx = &mctp->msg_ctxs[i];
if (ctx->src == src && ctx->dest == dest && ctx->tag == tag)
return ctx;
}
return NULL;
}
static struct mctp_msg_ctx *mctp_msg_ctx_create(struct mctp *mctp, uint8_t src,
uint8_t dest, uint8_t tag)
{
struct mctp_msg_ctx *ctx = NULL;
unsigned int i;
for (i = 0; i < ARRAY_SIZE(mctp->msg_ctxs); i++) {
struct mctp_msg_ctx *tmp = &mctp->msg_ctxs[i];
if (!tmp->src) {
ctx = tmp;
break;
}
}
if (!ctx)
return NULL;
ctx->src = src;
ctx->dest = dest;
ctx->tag = tag;
ctx->buf_size = 0;
return ctx;
}
static void mctp_msg_ctx_drop(struct mctp_msg_ctx *ctx)
{
ctx->src = 0;
}
static void mctp_msg_ctx_reset(struct mctp_msg_ctx *ctx)
{
ctx->buf_size = 0;
ctx->fragment_size = 0;
}
static int mctp_msg_ctx_add_pkt(struct mctp_msg_ctx *ctx,
struct mctp_pktbuf *pkt, size_t max_size)
{
size_t len;
len = mctp_pktbuf_size(pkt) - sizeof(struct mctp_hdr);
if (len + ctx->buf_size < ctx->buf_size) {
return -1;
}
if (ctx->buf_size + len > ctx->buf_alloc_size) {
size_t new_alloc_size;
void *lbuf;
/* @todo: finer-grained allocation */
if (!ctx->buf_alloc_size) {
new_alloc_size = MAX(len, 4096UL);
} else {
new_alloc_size = MAX(ctx->buf_alloc_size * 2,
len + ctx->buf_size);
}
/* Don't allow heap to grow beyond a limit */
if (new_alloc_size > max_size)
return -1;
lbuf = __mctp_realloc(ctx->buf, new_alloc_size);
if (lbuf) {
ctx->buf = lbuf;
ctx->buf_alloc_size = new_alloc_size;
} else {
__mctp_free(ctx->buf);
return -1;
}
}
memcpy((uint8_t *)ctx->buf + ctx->buf_size, mctp_pktbuf_data(pkt), len);
ctx->buf_size += len;
return 0;
}
/* Core API functions */
struct mctp *mctp_init(void)
{
struct mctp *mctp;
mctp = __mctp_alloc(sizeof(*mctp));
if (!mctp)
return NULL;
memset(mctp, 0, sizeof(*mctp));
mctp->max_message_size = MCTP_MAX_MESSAGE_SIZE;
return mctp;
}
void mctp_set_max_message_size(struct mctp *mctp, size_t message_size)
{
mctp->max_message_size = message_size;
}
void mctp_set_capture_handler(struct mctp *mctp, mctp_capture_fn fn, void *user)
{
mctp->capture = fn;
mctp->capture_data = user;
}
static void mctp_bus_destroy(struct mctp_bus *bus)
{
while (bus->tx_queue_head) {
struct mctp_pktbuf *curr = bus->tx_queue_head;
bus->tx_queue_head = curr->next;
mctp_pktbuf_free(curr);
}
}
void mctp_destroy(struct mctp *mctp)
{
size_t i;
/* Cleanup message assembly contexts */
BUILD_ASSERT(ARRAY_SIZE(mctp->msg_ctxs) < SIZE_MAX);
for (i = 0; i < ARRAY_SIZE(mctp->msg_ctxs); i++) {
struct mctp_msg_ctx *tmp = &mctp->msg_ctxs[i];
if (tmp->buf)
__mctp_free(tmp->buf);
}
while (mctp->n_busses--)
mctp_bus_destroy(&mctp->busses[mctp->n_busses]);
__mctp_free(mctp->busses);
__mctp_free(mctp);
}
int mctp_set_rx_all(struct mctp *mctp, mctp_rx_fn fn, void *data)
{
mctp->message_rx = fn;
mctp->message_rx_data = data;
return 0;
}
static struct mctp_bus *find_bus_for_eid(struct mctp *mctp, mctp_eid_t dest
__attribute__((unused)))
{
if (mctp->n_busses == 0)
return NULL;
/* for now, just use the first bus. For full routing support,
* we will need a table of neighbours */
return &mctp->busses[0];
}
int mctp_register_bus(struct mctp *mctp, struct mctp_binding *binding,
mctp_eid_t eid)
{
int rc = 0;
/* todo: multiple busses */
assert(mctp->n_busses == 0);
mctp->n_busses = 1;
mctp->busses = __mctp_alloc(sizeof(struct mctp_bus));
if (!mctp->busses)
return -ENOMEM;
memset(mctp->busses, 0, sizeof(struct mctp_bus));
mctp->busses[0].binding = binding;
mctp->busses[0].eid = eid;
binding->bus = &mctp->busses[0];
binding->mctp = mctp;
mctp->route_policy = ROUTE_ENDPOINT;
if (binding->start) {
rc = binding->start(binding);
if (rc < 0) {
mctp_prerr("Failed to start binding: %d", rc);
binding->bus = NULL;
__mctp_free(mctp->busses);
mctp->busses = NULL;
mctp->n_busses = 0;
}
}
return rc;
}
void mctp_unregister_bus(struct mctp *mctp, struct mctp_binding *binding)
{
/*
* We only support one bus right now; once the call completes we will
* have no more busses
*/
mctp->n_busses = 0;
binding->mctp = NULL;
binding->bus = NULL;
free(mctp->busses);
}
int mctp_bridge_busses(struct mctp *mctp, struct mctp_binding *b1,
struct mctp_binding *b2)
{
int rc = 0;
assert(mctp->n_busses == 0);
mctp->busses = __mctp_alloc(2 * sizeof(struct mctp_bus));
if (!mctp->busses)
return -ENOMEM;
memset(mctp->busses, 0, 2 * sizeof(struct mctp_bus));
mctp->n_busses = 2;
mctp->busses[0].binding = b1;
b1->bus = &mctp->busses[0];
b1->mctp = mctp;
mctp->busses[1].binding = b2;
b2->bus = &mctp->busses[1];
b2->mctp = mctp;
mctp->route_policy = ROUTE_BRIDGE;
if (b1->start) {
rc = b1->start(b1);
if (rc < 0) {
mctp_prerr("Failed to start bridged bus %s: %d",
b1->name, rc);
goto done;
}
}
if (b2->start) {
rc = b2->start(b2);
if (rc < 0) {
mctp_prerr("Failed to start bridged bus %s: %d",
b2->name, rc);
goto done;
}
}
done:
return rc;
}
static inline bool mctp_ctrl_cmd_is_transport(struct mctp_ctrl_msg_hdr *hdr)
{
return ((hdr->command_code >= MCTP_CTRL_CMD_FIRST_TRANSPORT) &&
(hdr->command_code <= MCTP_CTRL_CMD_LAST_TRANSPORT));
}
static bool mctp_ctrl_handle_msg(struct mctp_bus *bus, mctp_eid_t src,
uint8_t msg_tag, bool tag_owner, void *buffer,
size_t length)
{
struct mctp_ctrl_msg_hdr *msg_hdr = buffer;
/*
* Control message is received. If a transport control message handler
* is provided, it will called. If there is no dedicated handler, this
* function returns false and data can be handled by the generic
* message handler. The transport control message handler will be
* provided with messages in the command range 0xF0 - 0xFF.
*/
if (mctp_ctrl_cmd_is_transport(msg_hdr)) {
if (bus->binding->control_rx != NULL) {
/* MCTP bus binding handler */
bus->binding->control_rx(src, msg_tag, tag_owner,
bus->binding->control_rx_data,
buffer, length);
return true;
}
}
/*
* Command was not handled, due to lack of specific callback.
* It will be passed to regular message_rx handler.
*/
return false;
}
static inline bool mctp_rx_dest_is_local(struct mctp_bus *bus, mctp_eid_t dest)
{
return dest == bus->eid || dest == MCTP_EID_NULL ||
dest == MCTP_EID_BROADCAST;
}
static inline bool mctp_ctrl_cmd_is_request(struct mctp_ctrl_msg_hdr *hdr)
{
return hdr->ic_msg_type == MCTP_CTRL_HDR_MSG_TYPE &&
hdr->rq_dgram_inst & MCTP_CTRL_HDR_FLAG_REQUEST;
}
/*
* Receive the complete MCTP message and route it.
* Asserts:
* 'buf' is not NULL.
*/
static void mctp_rx(struct mctp *mctp, struct mctp_bus *bus, mctp_eid_t src,
mctp_eid_t dest, bool tag_owner, uint8_t msg_tag, void *buf,
size_t len)
{
assert(buf != NULL);
if (mctp->route_policy == ROUTE_ENDPOINT &&
mctp_rx_dest_is_local(bus, dest)) {
/* Handle MCTP Control Messages: */
if (len >= sizeof(struct mctp_ctrl_msg_hdr)) {
struct mctp_ctrl_msg_hdr *msg_hdr = buf;
/*
* Identify if this is a control request message.
* See DSP0236 v1.3.0 sec. 11.5.
*/
if (mctp_ctrl_cmd_is_request(msg_hdr)) {
bool handled;
handled = mctp_ctrl_handle_msg(
bus, src, msg_tag, tag_owner, buf, len);
if (handled)
return;
}
}
if (mctp->message_rx)
mctp->message_rx(src, tag_owner, msg_tag,
mctp->message_rx_data, buf, len);
}
if (mctp->route_policy == ROUTE_BRIDGE) {
int i;
for (i = 0; i < mctp->n_busses; i++) {
struct mctp_bus *dest_bus = &mctp->busses[i];
if (dest_bus == bus)
continue;
mctp_message_tx_on_bus(dest_bus, src, dest, tag_owner,
msg_tag, buf, len);
}
}
}
void mctp_bus_rx(struct mctp_binding *binding, struct mctp_pktbuf *pkt)
{
struct mctp_bus *bus = binding->bus;
struct mctp *mctp = binding->mctp;
uint8_t flags, exp_seq, seq, tag;
struct mctp_msg_ctx *ctx;
struct mctp_hdr *hdr;
bool tag_owner;
size_t len;
void *p;
int rc;
assert(bus);
/* Drop packet if it was smaller than mctp hdr size */
if (mctp_pktbuf_size(pkt) <= sizeof(struct mctp_hdr))
goto out;
if (mctp->capture)
mctp->capture(pkt, MCTP_MESSAGE_CAPTURE_INCOMING,
mctp->capture_data);
hdr = mctp_pktbuf_hdr(pkt);
/* small optimisation: don't bother reassembly if we're going to
* drop the packet in mctp_rx anyway */
if (mctp->route_policy == ROUTE_ENDPOINT && hdr->dest != bus->eid)
goto out;
flags = hdr->flags_seq_tag & (MCTP_HDR_FLAG_SOM | MCTP_HDR_FLAG_EOM);
tag = (hdr->flags_seq_tag >> MCTP_HDR_TAG_SHIFT) & MCTP_HDR_TAG_MASK;
seq = (hdr->flags_seq_tag >> MCTP_HDR_SEQ_SHIFT) & MCTP_HDR_SEQ_MASK;
tag_owner = (hdr->flags_seq_tag >> MCTP_HDR_TO_SHIFT) &
MCTP_HDR_TO_MASK;
switch (flags) {
case MCTP_HDR_FLAG_SOM | MCTP_HDR_FLAG_EOM:
/* single-packet message - send straight up to rx function,
* no need to create a message context */
len = pkt->end - pkt->mctp_hdr_off - sizeof(struct mctp_hdr);
p = pkt->data + pkt->mctp_hdr_off + sizeof(struct mctp_hdr);
mctp_rx(mctp, bus, hdr->src, hdr->dest, tag_owner, tag, p, len);
break;
case MCTP_HDR_FLAG_SOM:
/* start of a new message - start the new context for
* future message reception. If an existing context is
* already present, drop it. */
ctx = mctp_msg_ctx_lookup(mctp, hdr->src, hdr->dest, tag);
if (ctx) {
mctp_msg_ctx_reset(ctx);
} else {
ctx = mctp_msg_ctx_create(mctp, hdr->src, hdr->dest,
tag);
/* If context creation fails due to exhaution of contexts we
* can support, drop the packet */
if (!ctx) {
mctp_prdebug("Context buffers exhausted.");
goto out;
}
}
/* Save the fragment size, subsequent middle fragments
* should of the same size */
ctx->fragment_size = mctp_pktbuf_size(pkt);
rc = mctp_msg_ctx_add_pkt(ctx, pkt, mctp->max_message_size);
if (rc) {
mctp_msg_ctx_drop(ctx);
} else {
ctx->last_seq = seq;
}
break;
case MCTP_HDR_FLAG_EOM:
ctx = mctp_msg_ctx_lookup(mctp, hdr->src, hdr->dest, tag);
if (!ctx)
goto out;
exp_seq = (ctx->last_seq + 1) % 4;
if (exp_seq != seq) {
mctp_prdebug(
"Sequence number %d does not match expected %d",
seq, exp_seq);
mctp_msg_ctx_drop(ctx);
goto out;
}
len = mctp_pktbuf_size(pkt);
if (len > ctx->fragment_size) {
mctp_prdebug("Unexpected fragment size. Expected"
" less than %zu, received = %zu",
ctx->fragment_size, len);
mctp_msg_ctx_drop(ctx);
goto out;
}
rc = mctp_msg_ctx_add_pkt(ctx, pkt, mctp->max_message_size);
if (!rc)
mctp_rx(mctp, bus, ctx->src, ctx->dest, tag_owner, tag,
ctx->buf, ctx->buf_size);
mctp_msg_ctx_drop(ctx);
break;
case 0:
/* Neither SOM nor EOM */
ctx = mctp_msg_ctx_lookup(mctp, hdr->src, hdr->dest, tag);
if (!ctx)
goto out;
exp_seq = (ctx->last_seq + 1) % 4;
if (exp_seq != seq) {
mctp_prdebug(
"Sequence number %d does not match expected %d",
seq, exp_seq);
mctp_msg_ctx_drop(ctx);
goto out;
}
len = mctp_pktbuf_size(pkt);
if (len != ctx->fragment_size) {
mctp_prdebug("Unexpected fragment size. Expected = %zu "
"received = %zu",
ctx->fragment_size, len);
mctp_msg_ctx_drop(ctx);
goto out;
}
rc = mctp_msg_ctx_add_pkt(ctx, pkt, mctp->max_message_size);
if (rc) {
mctp_msg_ctx_drop(ctx);
goto out;
}
ctx->last_seq = seq;
break;
}
out:
mctp_pktbuf_free(pkt);
}
static int mctp_packet_tx(struct mctp_bus *bus, struct mctp_pktbuf *pkt)
{
struct mctp *mctp = bus->binding->mctp;
if (bus->state != mctp_bus_state_tx_enabled)
return -1;
if (mctp->capture)
mctp->capture(pkt, MCTP_MESSAGE_CAPTURE_OUTGOING,
mctp->capture_data);
return bus->binding->tx(bus->binding, pkt);
}
static void mctp_send_tx_queue(struct mctp_bus *bus)
{
struct mctp_pktbuf *pkt;
while ((pkt = bus->tx_queue_head)) {
int rc;
rc = mctp_packet_tx(bus, pkt);
switch (rc) {
/* If transmission succeded, or */
case 0:
/* If the packet is somehow too large */
case -EMSGSIZE:
/* Drop the packet */
bus->tx_queue_head = pkt->next;
mctp_pktbuf_free(pkt);
break;
/* If the binding was busy, or */
case -EBUSY:
/* Some other unknown error occurred */
default:
/* Make sure the tail pointer is consistent and retry later */
goto cleanup_tail;
};
}
cleanup_tail:
if (!bus->tx_queue_head)
bus->tx_queue_tail = NULL;
}
void mctp_binding_set_tx_enabled(struct mctp_binding *binding, bool enable)
{
struct mctp_bus *bus = binding->bus;
switch (bus->state) {
case mctp_bus_state_constructed:
if (!enable)
return;
if (binding->pkt_size < MCTP_PACKET_SIZE(MCTP_BTU)) {
mctp_prerr(
"Cannot start %s binding with invalid MTU: %zu",
binding->name,
MCTP_BODY_SIZE(binding->pkt_size));
return;
}
bus->state = mctp_bus_state_tx_enabled;
mctp_prinfo("%s binding started", binding->name);
return;
case mctp_bus_state_tx_enabled:
if (enable)
return;
bus->state = mctp_bus_state_tx_disabled;
mctp_prdebug("%s binding Tx disabled", binding->name);
return;
case mctp_bus_state_tx_disabled:
if (!enable)
return;
bus->state = mctp_bus_state_tx_enabled;
mctp_prdebug("%s binding Tx enabled", binding->name);
mctp_send_tx_queue(bus);
return;
}
}
static int mctp_message_tx_on_bus(struct mctp_bus *bus, mctp_eid_t src,
mctp_eid_t dest, bool tag_owner,
uint8_t msg_tag, void *msg, size_t msg_len)
{
size_t max_payload_len, payload_len, p;
struct mctp_pktbuf *pkt;
struct mctp_hdr *hdr;
int i;
if (bus->state == mctp_bus_state_constructed)
return -ENXIO;
if ((msg_tag & MCTP_HDR_TAG_MASK) != msg_tag)
return -EINVAL;
max_payload_len = MCTP_BODY_SIZE(bus->binding->pkt_size);
{
const bool valid_mtu = max_payload_len >= MCTP_BTU;
assert(valid_mtu);
if (!valid_mtu)
return -EINVAL;
}
mctp_prdebug(
"%s: Generating packets for transmission of %zu byte message from %hhu to %hhu",
__func__, msg_len, src, dest);
/* queue up packets, each of max MCTP_MTU size */
for (p = 0, i = 0; p < msg_len; i++) {
payload_len = msg_len - p;
if (payload_len > max_payload_len)
payload_len = max_payload_len;
pkt = mctp_pktbuf_alloc(bus->binding,
payload_len + sizeof(*hdr));
hdr = mctp_pktbuf_hdr(pkt);
hdr->ver = bus->binding->version & 0xf;
hdr->dest = dest;
hdr->src = src;
hdr->flags_seq_tag = (tag_owner << MCTP_HDR_TO_SHIFT) |
(msg_tag << MCTP_HDR_TAG_SHIFT);
if (i == 0)
hdr->flags_seq_tag |= MCTP_HDR_FLAG_SOM;
if (p + payload_len >= msg_len)
hdr->flags_seq_tag |= MCTP_HDR_FLAG_EOM;
hdr->flags_seq_tag |= (i & MCTP_HDR_SEQ_MASK)
<< MCTP_HDR_SEQ_SHIFT;
memcpy(mctp_pktbuf_data(pkt), (uint8_t *)msg + p, payload_len);
/* add to tx queue */
if (bus->tx_queue_tail)
bus->tx_queue_tail->next = pkt;
else
bus->tx_queue_head = pkt;
bus->tx_queue_tail = pkt;
p += payload_len;
}
mctp_prdebug("%s: Enqueued %d packets", __func__, i);
mctp_send_tx_queue(bus);
return 0;
}
int mctp_message_tx(struct mctp *mctp, mctp_eid_t eid, bool tag_owner,
uint8_t msg_tag, void *msg, size_t msg_len)
{
struct mctp_bus *bus;
/* TODO: Protect against same tag being used across
* different callers */
if ((msg_tag & MCTP_HDR_TAG_MASK) != msg_tag) {
mctp_prerr("Incorrect message tag %u passed.", msg_tag);
return -EINVAL;
}
bus = find_bus_for_eid(mctp, eid);
if (!bus)
return 0;
return mctp_message_tx_on_bus(bus, bus->eid, eid, tag_owner, msg_tag,
msg, msg_len);
}