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common/read_peer_msg: deconstruct into individual helper routines.
The One Big API is confusing, and has enough corner cases that we should ditch it rather than add more. See: https://www.sandimetz.com/blog/2016/1/20/the-wrong-abstraction In particular, when openingd is changed to chat to peers even when it's not actively opening a channel, it wants to handle (most) errors by continuing, not calling peer_failed(). This exposes the constituent parts. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell
parent
74d428109a
commit
09cce4a9c7
4 changed files with 212 additions and 50 deletions
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@ -36,8 +36,12 @@ void peer_failed_received_errmsg(int peer_fd, int gossip_fd,
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const char *desc,
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const struct channel_id *channel_id)
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{
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u8 *msg = towire_status_peer_error(NULL, channel_id,
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desc, cs, NULL);
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static const struct channel_id all_channels;
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u8 *msg;
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if (!channel_id)
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channel_id = &all_channels;
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msg = towire_status_peer_error(NULL, channel_id, desc, cs, NULL);
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peer_billboard(true, "Received error from peer: %s", desc);
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status_send_fatal(take(msg), peer_fd, gossip_fd);
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}
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@ -21,7 +21,8 @@ void peer_failed_(int peer_fd, int gossip_fd,
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const char *fmt, ...)
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PRINTF_FMT(5,6) NORETURN;
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/* We're failing because peer sent us an error message */
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/* We're failing because peer sent us an error message: NULL
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* channel_id means all channels. */
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void peer_failed_received_errmsg(int peer_fd, int gossip_fd,
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struct crypto_state *cs,
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const char *desc,
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@ -11,6 +11,77 @@
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#include <wire/peer_wire.h>
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#include <wire/wire_sync.h>
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u8 *peer_or_gossip_sync_read(const tal_t *ctx,
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int peer_fd, int gossip_fd,
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struct crypto_state *cs,
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bool *from_gossipd)
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{
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fd_set readfds;
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u8 *msg;
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FD_ZERO(&readfds);
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FD_SET(peer_fd, &readfds);
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FD_SET(gossip_fd, &readfds);
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select(peer_fd > gossip_fd ? peer_fd + 1 : gossip_fd + 1,
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&readfds, NULL, NULL, NULL);
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if (FD_ISSET(gossip_fd, &readfds)) {
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msg = wire_sync_read(ctx, gossip_fd);
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if (!msg)
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status_failed(STATUS_FAIL_GOSSIP_IO,
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"Error reading gossip msg: %s",
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strerror(errno));
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*from_gossipd = true;
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return msg;
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}
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msg = sync_crypto_read(ctx, cs, peer_fd);
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if (!msg)
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peer_failed_connection_lost();
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*from_gossipd = false;
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return msg;
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}
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bool is_peer_error(const tal_t *ctx, const u8 *msg,
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const struct channel_id *channel_id,
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char **desc, bool *all_channels)
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{
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struct channel_id err_chanid;
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if (fromwire_peektype(msg) != WIRE_ERROR)
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return false;
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*desc = sanitize_error(ctx, msg, &err_chanid);
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/* BOLT #1:
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*
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* The channel is referred to by `channel_id`, unless `channel_id` is
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* 0 (i.e. all bytes are 0), in which case it refers to all channels.
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* ...
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* The receiving node:
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* - upon receiving `error`:
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* - MUST fail the channel referred to by the error message, if that
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* channel is with the sending node.
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* - if no existing channel is referred to by the message:
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* - MUST ignore the message.
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*/
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*all_channels = channel_id_is_all(&err_chanid);
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if (!*all_channels && !channel_id_eq(&err_chanid, channel_id))
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*desc = tal_free(*desc);
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return true;
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}
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bool is_wrong_channel(const u8 *msg, const struct channel_id *expected,
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struct channel_id *actual)
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{
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if (!extract_channel_id(msg, actual))
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return false;
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return !channel_id_eq(expected, actual);
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}
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void handle_gossip_msg_(const u8 *msg TAKES, int peer_fd,
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struct crypto_state *cs,
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bool (*send_msg)(struct crypto_state *cs, int fd,
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@ -42,6 +113,53 @@ void handle_gossip_msg_(const u8 *msg TAKES, int peer_fd,
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tal_free(msg);
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}
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bool handle_peer_gossip_or_error(int peer_fd, int gossip_fd,
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struct crypto_state *cs,
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const struct channel_id *channel_id,
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const u8 *msg TAKES)
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{
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char *err;
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bool all_channels;
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struct channel_id actual;
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if (is_msg_for_gossipd(msg)) {
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wire_sync_write(gossip_fd, msg);
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/* wire_sync_write takes, so don't take again. */
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return true;
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}
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if (is_peer_error(tmpctx, msg, channel_id, &err, &all_channels)) {
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if (err)
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peer_failed_received_errmsg(peer_fd, gossip_fd,
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cs, err,
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all_channels
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? NULL : channel_id);
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/* Ignore unknown channel errors. */
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goto handled;
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}
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/* They're talking about a different channel? */
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if (is_wrong_channel(msg, channel_id, &actual)) {
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status_trace("Rejecting %s for unknown channel_id %s",
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wire_type_name(fromwire_peektype(msg)),
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type_to_string(tmpctx, struct channel_id, &actual));
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if (!sync_crypto_write(cs, peer_fd,
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take(towire_errorfmt(NULL, &actual,
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"Multiple channels"
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" unsupported"))))
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peer_failed_connection_lost();
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goto handled;
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}
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return false;
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handled:
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if (taken(msg))
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tal_free(msg);
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return true;
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}
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u8 *read_peer_msg_(const tal_t *ctx,
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int peer_fd, int gossip_fd,
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struct crypto_state *cs,
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@ -51,31 +169,24 @@ u8 *read_peer_msg_(const tal_t *ctx,
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void *arg)
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{
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u8 *msg;
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struct channel_id chanid;
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fd_set readfds;
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bool from_gossipd, all_channels;
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struct channel_id actual;
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char *err;
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FD_ZERO(&readfds);
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FD_SET(peer_fd, &readfds);
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if (gossip_fd >= 0)
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FD_SET(gossip_fd, &readfds);
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select(peer_fd > gossip_fd ? peer_fd + 1 : gossip_fd + 1,
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&readfds, NULL, NULL, NULL);
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if (gossip_fd >= 0 && FD_ISSET(gossip_fd, &readfds)) {
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msg = wire_sync_read(NULL, gossip_fd);
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if (gossip_fd > 0) {
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msg = peer_or_gossip_sync_read(ctx, peer_fd, gossip_fd,
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cs, &from_gossipd);
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} else {
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msg = sync_crypto_read(ctx, cs, peer_fd);
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if (!msg)
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status_failed(STATUS_FAIL_GOSSIP_IO,
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"Error reading gossip msg: %s",
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strerror(errno));
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handle_gossip_msg_(msg, peer_fd, cs, send_reply, arg);
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return NULL;
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peer_failed_connection_lost();
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from_gossipd = false;
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}
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msg = sync_crypto_read(ctx, cs, peer_fd);
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if (!msg)
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peer_failed_connection_lost();
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if (from_gossipd) {
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handle_gossip_msg_(take(msg), peer_fd, cs, send_reply, arg);
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return NULL;
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}
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if (is_msg_for_gossipd(msg)) {
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/* Forward to gossip daemon */
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@ -83,41 +194,24 @@ u8 *read_peer_msg_(const tal_t *ctx,
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return NULL;
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}
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if (fromwire_peektype(msg) == WIRE_ERROR) {
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char *err = sanitize_error(msg, msg, &chanid);
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/* BOLT #1:
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*
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* The channel is referred to by `channel_id`, unless
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* `channel_id` is 0 (i.e. all bytes are 0), in which
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* case it refers to all channels.
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* ...
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* The receiving node:
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* - upon receiving `error`:
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* - MUST fail the channel referred to by the error
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* message, if that channel is with the sending node.
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* - if no existing channel is referred to by the
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* message:
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* - MUST ignore the message.
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*/
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if (channel_id_eq(&chanid, channel)
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|| channel_id_is_all(&chanid)) {
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if (is_peer_error(tmpctx, msg, channel, &err, &all_channels)) {
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if (err)
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peer_failed_received_errmsg(peer_fd, gossip_fd,
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cs, err, &chanid);
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}
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cs, err,
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all_channels
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? NULL : channel);
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/* Ignore unknown channel errors. */
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return tal_free(msg);
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}
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/* They're talking about a different channel? */
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if (extract_channel_id(msg, &chanid)
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&& !channel_id_eq(&chanid, channel)) {
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if (is_wrong_channel(msg, channel, &actual)) {
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status_trace("Rejecting %s for unknown channel_id %s",
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wire_type_name(fromwire_peektype(msg)),
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type_to_string(tmpctx, struct channel_id, &chanid));
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type_to_string(tmpctx, struct channel_id, &actual));
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if (!send_reply(cs, peer_fd,
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take(towire_errorfmt(NULL, &chanid,
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take(towire_errorfmt(NULL, &actual,
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"Multiple channels"
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" unsupported")),
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arg))
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@ -8,6 +8,69 @@
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struct crypto_state;
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struct channel_id;
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/**
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* peer_or_gossip_sync_read - read a peer message, or maybe a gossip msg.
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* @ctx: context to allocate return packet from.
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* @peer_fd, @gossip_fd: peer and gossip fd.
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* @cs: the cryptostate (updated)
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* @from_gossipd: true if the msg was from gossipd, otherwise false.
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*
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* Will call peer_failed_connection_lost() or
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* status_failed(STATUS_FAIL_GOSSIP_IO) or return a message.
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*
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* Usually, you should call handle_gossip_msg if *@from_gossipd is
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* true, otherwise if is_peer_error() handle the error, otherwise if
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* is_msg_for_gossipd() then send to gossipd, otherwise if is
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* is_wrong_channel() send that as a reply. Otherwise it should be
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* a valid message.
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*/
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u8 *peer_or_gossip_sync_read(const tal_t *ctx,
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int peer_fd, int gossip_fd,
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struct crypto_state *cs,
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bool *from_gossipd);
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/**
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* is_peer_error - if it's an error, describe if it applies to this channel.
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* @ctx: context to allocate return from.
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* @msg: the peer message.
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* @channel_id: the channel id of the current channel.
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* @desc: set to non-NULL if this describes a channel we care about.
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* @all_channels: set to true if this applies to all channels.
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*
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* If @desc is NULL, ignore this message. Otherwise, that's usually passed
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* to peer_failed_received_errmsg().
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*/
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bool is_peer_error(const tal_t *ctx, const u8 *msg,
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const struct channel_id *channel_id,
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char **desc, bool *all_channels);
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/**
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* is_wrong_channel - if it's a message about a different channel, return true
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* @msg: the peer message.
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* @channel_id: the channel id of the current channel.
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* @actual: set to the actual channel id if this returns false.
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*
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* Note that this only handles some message types, returning false for others.
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*/
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bool is_wrong_channel(const u8 *msg, const struct channel_id *expected,
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struct channel_id *actual);
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/**
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* handle_peer_gossip_or_error - simple handler for all the above cases.
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* @peer_fd, @gossip_fd: peer and gossip fd.
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* @cs: the cryptostate (updated)
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* @msg: the peer message (only taken if returns true).
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*
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* This returns true if it handled the packet: a gossip packet (forwarded
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* to gossipd), an error packet (causes peer_failed_received_errmsg or
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* ignored), or a message about the wrong channel (sends sync error reply).
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*/
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bool handle_peer_gossip_or_error(int peer_fd, int gossip_fd,
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struct crypto_state *cs,
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const struct channel_id *channel_id,
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const u8 *msg TAKES);
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/**
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* read_peer_msg - read & decode in a peer message, handling common ones.
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* @ctx: context to allocate return packet from.
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