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jitterbug/wire.c
hippoz ec156a1b14
basic unicast relay mechanism
2022-12-23 23:58:18 +02:00

380 lines
14 KiB
C
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#include <string.h>
#include <stdio.h>
#include "try.h"
#include "wire.h"
bool wire_align(wire_context_t *c, uint32_t alignment)
{
if ((c->byte_cursor % alignment) == 0) {
return true;
}
uint32_t new_cursor = c->byte_cursor + alignment - (c->byte_cursor % alignment);
if (new_cursor >= c->data_len || new_cursor < c->byte_cursor) {
return false;
}
c->byte_cursor = new_cursor;
return true;
}
bool wire_write_align(wire_context_t *c, uint32_t alignment)
{
if ((c->byte_cursor % alignment) == 0) {
return true;
}
uint32_t new_cursor = c->byte_cursor + alignment - (c->byte_cursor % alignment);
if (new_cursor >= c->data_len || new_cursor < c->byte_cursor) {
return false;
}
while (c->byte_cursor < new_cursor) {
c->data[c->byte_cursor] = '\0';
c->byte_cursor++;
}
return true;
}
// SPEC: https://dbus.freedesktop.org/doc/dbus-specification.html#id-1.4.6
_WIRE_DEF_BYTE_TYPE(i8, int8_t);
_WIRE_DEF_BYTE_TYPE(u8, uint8_t);
_WIRE_DEF_TYPE(i16, int16_t, 2);
_WIRE_DEF_TYPE(u16, uint16_t, 2);
_WIRE_DEF_TYPE(i32, int32_t, 4);
_WIRE_DEF_TYPE(u32, uint32_t, 4);
_WIRE_DEF_TYPE(boolean, uint32_t, 4);
char *wire_get_string(wire_context_t *c, uint32_t *out_len)
{
uint32_t len = *TRY_NONNULL(uint32_t*, wire_get_u32(c), NULL);
if (out_len) {
*out_len = len;
}
uint32_t new_cursor = c->byte_cursor + len + 1; /* + 1 because of the extra null termination that strings have */
if (new_cursor >= c->data_len) {
return NULL;
}
char *str = (char *)&c->data[c->byte_cursor];
c->byte_cursor = new_cursor;
return str;
}
char *wire_set_string(wire_context_t *c, const char *str)
{
uint32_t len = strlen(str);
TRY_NONNULL(uint32_t*, wire_set_u32(c, len), NULL);
uint32_t new_cursor = c->byte_cursor + len + 1; /* + 1 because of the extra null termination that strings have */
if (new_cursor >= c->data_len) {
return NULL;
}
// TODO?
char *dest = (char*)&c->data[c->byte_cursor];
memcpy(dest, str, len + 1);
c->byte_cursor = new_cursor;
return dest;
}
char *wire_get_signature(wire_context_t *c, uint8_t *out_len)
{
uint8_t len = *TRY_NONNULL(uint8_t*, wire_get_u8(c), NULL);
if (out_len) {
*out_len = len;
}
uint32_t new_cursor = c->byte_cursor + len + 1; /* + 1 because of the extra null termination that strings have */
if (new_cursor >= c->data_len) {
return NULL;
}
char *str = (char *)&c->data[c->byte_cursor];
c->byte_cursor = new_cursor;
return str;
}
char *wire_set_signature(wire_context_t *c, const char *str)
{
uint8_t len = strlen(str);
TRY_NONNULL(uint8_t*, wire_set_u8(c, len), NULL);
uint32_t new_cursor = c->byte_cursor + len + 1; /* + 1 because of the extra null termination that strings have */
if (new_cursor >= c->data_len) {
return NULL;
}
// TODO?
char *dest = (char*)&c->data[c->byte_cursor];
memcpy(dest, str, len + 1);
c->byte_cursor = new_cursor;
return dest;
}
int wire_parse_message(wire_context_t *c, wire_message_t *msg)
{
// SPEC: https://dbus.freedesktop.org/doc/dbus-specification.html#message-protocol-messages
msg->endianness = *TRY_NONNULL(uint8_t*, wire_get_u8(c), -1);
msg->type = *TRY_NONNULL(uint8_t*, wire_get_u8(c), -1);
msg->flags = *TRY_NONNULL(uint8_t*, wire_get_u8(c), -1);
msg->protocol_version = *TRY_NONNULL(uint8_t*, wire_get_u8(c), -1);
msg->body_length = *TRY_NONNULL(uint32_t*, wire_get_u32(c), -1);
msg->serial = *TRY_NONNULL(uint32_t*, wire_get_u32(c), -1);
msg->header_fields_length = *TRY_NONNULL(uint32_t*, wire_get_u32(c), -1);
size_t header_fields_end = c->byte_cursor + msg->header_fields_length;
printf(" > start parse!\n");
while (c->byte_cursor < header_fields_end) {
uint8_t field_code = *TRY_NONNULL(uint8_t*, wire_get_u8(c), -1);
TRY_NONNULL(char*, wire_get_signature(c, NULL), -1);
switch (field_code) {
case DBUS_HEADER_FIELD_PATH: /* through */
case DBUS_HEADER_FIELD_INTERFACE: /* through */
case DBUS_HEADER_FIELD_MEMBER: /* through */
case DBUS_HEADER_FIELD_DESTINATION: {
char *str = TRY_NONNULL(char*, wire_get_string(c, NULL), -1);
printf("field: %s\n", str);
msg->fields[field_code].t.str = str;
} break;
case DBUS_HEADER_FIELD_SIGNATURE: {
char *str = TRY_NONNULL(char*, wire_get_signature(c, NULL), -1);
printf("field: %s\n", str);
msg->fields[field_code].t.str = str;
} break;
case DBUS_HEADER_FIELD_REPLY_SERIAL: {
uint32_t u = *TRY_NONNULL(uint32_t*, wire_get_u32(c), -1);
printf("field: %d\n", u);
msg->fields[field_code].t.u32 = u;
} break;
default: {
printf("header: unknown field: %d\n", field_code);
return -1;
} break;
}
msg->fields[field_code].present = true;
// Structs are always aligned to `8`.
// SPEC: https://dbus.freedesktop.org/doc/dbus-specification.html#id-1.4.6
TRY_NONNULL(bool, wire_align(c, 8), -1);
if (msg->header_fields_count++ > WIRE_MESSAGE_MAX_HEADER_FIELDS) {
return -1;
}
}
printf(" > parsed!!\n");
/* header ends at 8 byte boundry */
TRY_NONNULL(bool, wire_align(c, 8), -1);
return 0;
}
int wire_compose_reply(wire_context_t *c, wire_message_t *msg, const char *signature, uint32_t **out_body_length)
{
TRY_NONNULL(uint8_t*, wire_set_u8(c, msg->endianness), -1); /* endianness */
TRY_NONNULL(uint8_t*, wire_set_u8(c, DBUS_MESSAGE_METHOD_RETURN), -1); /* type */
TRY_NONNULL(uint8_t*, wire_set_u8(c, 0), -1); /* flags */
TRY_NONNULL(uint8_t*, wire_set_u8(c, DBUS_PROTOCOL_VERSION), -1); /* protocol_version */
uint32_t *body_length = TRY_NONNULL(uint32_t*, wire_set_u32(c, 0), -1); /* body length */
TRY_NONNULL(uint32_t*, wire_set_u32(c, msg->serial+1), -1); /* serial */
uint32_t *header_fields_length = TRY_NONNULL(uint32_t*, wire_set_u32(c, 0), -1); /* header_fields_length */
uint32_t header_fields_start = c->byte_cursor;
/* header fields */
{
/* SIGNATURE */
{
/* byte (field code) */
TRY_NONNULL(uint8_t*, wire_set_u8(c, DBUS_HEADER_FIELD_SIGNATURE), -1);
/* variant */
/* signature */
TRY_NONNULL(char*, wire_set_signature(c, "g"), -1);
/* signature */
TRY_NONNULL(char*, wire_set_signature(c, signature), -1);
// need to align to 8 byte boundry after each array element?
TRY_NONNULL(bool, wire_write_align(c, 8), -1);
}
/* REPLY_SERIAL */
{
/* byte (field code) */
TRY_NONNULL(uint8_t*, wire_set_u8(c, DBUS_HEADER_FIELD_REPLY_SERIAL), -1);
/* variant */
/* signature */
TRY_NONNULL(char*, wire_set_signature(c, "u"), -1);
/* reply serial */
TRY_NONNULL(uint32_t*, wire_set_u32(c, msg->serial), -1);
}
}
*header_fields_length = c->byte_cursor - header_fields_start;
// header ends on an 8 byte alignment
TRY_NONNULL(bool, wire_write_align(c, 8), -1);
if (out_body_length) {
*out_body_length = body_length;
}
return 0;
}
int wire_compose_error(wire_context_t *c, wire_message_t *msg, const char *error_name)
{
TRY_NONNULL(uint8_t*, wire_set_u8(c, msg->endianness), -1); /* endianness */
TRY_NONNULL(uint8_t*, wire_set_u8(c, DBUS_MESSAGE_ERROR), -1); /* type */
TRY_NONNULL(uint8_t*, wire_set_u8(c, 0), -1); /* flags */
TRY_NONNULL(uint8_t*, wire_set_u8(c, DBUS_PROTOCOL_VERSION), -1); /* protocol_version */
TRY_NONNULL(uint32_t*, wire_set_u32(c, 0), -1); /* body length */
TRY_NONNULL(uint32_t*, wire_set_u32(c, msg->serial+1), -1); /* serial */
uint32_t *header_fields_length = TRY_NONNULL(uint32_t*, wire_set_u32(c, 0), -1); /* header_fields_length */
uint32_t header_fields_start = c->byte_cursor;
/* header fields */
{
/* ERROR_NAME */
{
/* byte (field code) */
TRY_NONNULL(uint8_t*, wire_set_u8(c, DBUS_HEADER_FIELD_ERROR_NAME), -1);
/* variant */
/* signature */
TRY_NONNULL(char*, wire_set_signature(c, "s"), -1);
/* string */
TRY_NONNULL(char*, wire_set_string(c, error_name), -1);
// need to align to 8 byte boundry after each array element?
TRY_NONNULL(bool, wire_write_align(c, 8), -1);
}
/* REPLY_SERIAL */
{
/* byte (field code) */
TRY_NONNULL(uint8_t*, wire_set_u8(c, DBUS_HEADER_FIELD_REPLY_SERIAL), -1);
/* variant */
/* signature */
TRY_NONNULL(char*, wire_set_signature(c, "u"), -1);
/* reply serial */
TRY_NONNULL(uint32_t*, wire_set_u32(c, msg->serial), -1);
}
}
*header_fields_length = c->byte_cursor - header_fields_start;
// header ends on an 8 byte alignment
TRY_NONNULL(bool, wire_write_align(c, 8), -1);
return 0;
}
int wire_compose_unicast_reply(wire_context_t *c, wire_context_t *msg_c, wire_message_t *msg, char *sender_unique_name)
{
TRY_NONNULL(uint8_t*, wire_set_u8(c, msg->endianness), -1); /* endianness */
TRY_NONNULL(uint8_t*, wire_set_u8(c, msg->type), -1); /* type */
TRY_NONNULL(uint8_t*, wire_set_u8(c, 0), -1); /* flags */
TRY_NONNULL(uint8_t*, wire_set_u8(c, DBUS_PROTOCOL_VERSION), -1); /* protocol_version */
TRY_NONNULL(uint32_t*, wire_set_u32(c, msg->body_length), -1); /* body length */
TRY_NONNULL(uint32_t*, wire_set_u32(c, msg->serial), -1); /* serial */
uint32_t *header_fields_length = TRY_NONNULL(uint32_t*, wire_set_u32(c, 0), -1); /* header_fields_length */
uint32_t header_fields_start = c->byte_cursor;
switch (msg->type) {
case DBUS_MESSAGE_METHOD_CALL: {
// these fields are required for DBUS_MESSAGE_METHOD_CALL, so we must (hackily) check for their presence
// interface is not strictly required by the spec, however we require it here anyways
wire_message_field_t *path_field = &msg->fields[DBUS_HEADER_FIELD_PATH];
wire_message_field_t *interface_field = &msg->fields[DBUS_HEADER_FIELD_INTERFACE];
wire_message_field_t *member_field = &msg->fields[DBUS_HEADER_FIELD_MEMBER];
wire_message_field_t *signature_field = &msg->fields[DBUS_HEADER_FIELD_SIGNATURE];
if (!path_field->present || !interface_field->present || !interface_field->present) {
return -1;
}
TRY_NONNULL(uint8_t*, wire_set_u8(c, DBUS_HEADER_FIELD_PATH), -1);
TRY_NONNULL(char*, wire_set_signature(c, "o"), -1);
TRY_NONNULL(char*, wire_set_string(c, path_field->t.str), -1);
TRY_NONNULL(bool, wire_write_align(c, 8), -1);
TRY_NONNULL(uint8_t*, wire_set_u8(c, DBUS_HEADER_FIELD_INTERFACE), -1);
TRY_NONNULL(char*, wire_set_signature(c, "s"), -1);
TRY_NONNULL(char*, wire_set_string(c, interface_field->t.str), -1);
TRY_NONNULL(bool, wire_write_align(c, 8), -1);
TRY_NONNULL(uint8_t*, wire_set_u8(c, DBUS_HEADER_FIELD_MEMBER), -1);
TRY_NONNULL(char*, wire_set_signature(c, "s"), -1);
TRY_NONNULL(char*, wire_set_string(c, member_field->t.str), -1);
TRY_NONNULL(bool, wire_write_align(c, 8), -1);
if (signature_field->present) {
TRY_NONNULL(uint8_t*, wire_set_u8(c, DBUS_HEADER_FIELD_SIGNATURE), -1);
TRY_NONNULL(char*, wire_set_signature(c, "g"), -1);
TRY_NONNULL(char*, wire_set_signature(c, signature_field->t.str), -1);
TRY_NONNULL(bool, wire_write_align(c, 8), -1);
}
TRY_NONNULL(uint8_t*, wire_set_u8(c, DBUS_HEADER_FIELD_SENDER), -1);
TRY_NONNULL(char*, wire_set_signature(c, "s"), -1);
TRY_NONNULL(char*, wire_set_string(c, sender_unique_name), -1);
// last element, don't align
} break;
case DBUS_MESSAGE_METHOD_RETURN: {
wire_message_field_t *reply_serial_field = &msg->fields[DBUS_HEADER_FIELD_REPLY_SERIAL];
if (!reply_serial_field->present) {
return -1;
}
TRY_NONNULL(uint8_t*, wire_set_u8(c, DBUS_HEADER_FIELD_REPLY_SERIAL), -1);
TRY_NONNULL(char*, wire_set_signature(c, "u"), -1);
TRY_NONNULL(uint32_t*, wire_set_u32(c, reply_serial_field->t.u32), -1);
TRY_NONNULL(bool, wire_write_align(c, 8), -1);
wire_message_field_t *signature_field = &msg->fields[DBUS_HEADER_FIELD_SIGNATURE];
if (signature_field->present) {
TRY_NONNULL(uint8_t*, wire_set_u8(c, DBUS_HEADER_FIELD_SIGNATURE), -1);
TRY_NONNULL(char*, wire_set_signature(c, "g"), -1);
TRY_NONNULL(char*, wire_set_string(c, signature_field->t.str), -1);
TRY_NONNULL(bool, wire_write_align(c, 8), -1);
}
TRY_NONNULL(uint8_t*, wire_set_u8(c, DBUS_HEADER_FIELD_SENDER), -1);
TRY_NONNULL(char*, wire_set_signature(c, "s"), -1);
TRY_NONNULL(char*, wire_set_string(c, sender_unique_name), -1);
// last element, don't align
} break;
default: {
return -1;
} break;
}
*header_fields_length = c->byte_cursor - header_fields_start;
// header ends on an 8 byte alignment
TRY_NONNULL(bool, wire_write_align(c, 8), -1);
if (c->byte_cursor + msg->body_length > c->data_len) {
return -1;
}
memcpy(&c->data[c->byte_cursor], &msg_c->data[msg_c->byte_cursor], msg->body_length);
c->byte_cursor += msg->body_length;
return 0;
}
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