core-lightning/common/msg_queue.h
Rusty Russell d51fb5207a msg_queue: don't allow magic MSG_PASS_FD message for peers.
msg_queue was originally designed for inter-daemon comms, and so it has
a special mechanism to mark that we're trying to send an fd.  Unfortunately,
a peer could also send such a message, confusing us!

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2022-01-20 15:24:06 +10:30

37 lines
1.2 KiB
C

/* Helper for simple message queues. */
#ifndef LIGHTNING_COMMON_MSG_QUEUE_H
#define LIGHTNING_COMMON_MSG_QUEUE_H
#include "config.h"
#include <ccan/io/io.h>
#include <ccan/short_types/short_types.h>
/* Reserved type used to indicate we're actually passing an fd. */
#define MSG_PASS_FD 0xFFFF
/* Allocate a new msg queue; if we control all msgs we send/receive,
* we can pass fds. Otherwise, set @fd_passing to false. */
struct msg_queue *msg_queue_new(const tal_t *ctx, bool fd_passing);
/* If add is taken(), freed after sending. msg_wake() implied. */
void msg_enqueue(struct msg_queue *q, const u8 *add TAKES);
/* Get current queue length */
size_t msg_queue_length(const struct msg_queue *q);
/* Fd is closed after sending. msg_wake() implied. */
void msg_enqueue_fd(struct msg_queue *q, int fd);
/* Explicitly wake up a msg_queue_wait */
void msg_wake(const struct msg_queue *q);
/* Returns NULL if nothing to do. */
const u8 *msg_dequeue(struct msg_queue *q);
/* Returns -1 if not an fd: close after sending. */
int msg_extract_fd(const struct msg_queue *q, const u8 *msg);
#define msg_queue_wait(conn, q, next, arg) \
io_out_wait((conn), (q), (next), (arg))
#endif /* LIGHTNING_COMMON_MSG_QUEUE_H */