askrene: make "child.c" to be the explicit child entry point.

diff --git a/plugins/askrene/Makefile b/plugins/askrene/Makefile
index d676624e..29205911 100644
--- a/plugins/askrene/Makefile
+++ b/plugins/askrene/Makefile
@@ -2,10 +2,10 @@ PLUGIN_ASKRENE_PARENT_SRC := \
 	plugins/askrene/askrene.c \
 	plugins/askrene/datastore_wire.c \
 	plugins/askrene/layer.c \
-	plugins/askrene/reserve.c \
+	plugins/askrene/reserve.c
 
 PLUGIN_ASKRENE_CHILD_SRC := \
-	plugins/askrene/child/entry.c \
+	plugins/askrene/child/child.c \
 	plugins/askrene/child/mcf.c \
 	plugins/askrene/child/dijkstra.c \
 	plugins/askrene/child/flow.c \
diff --git a/plugins/askrene/askrene.c b/plugins/askrene/askrene.c
index 4910b858..a5709c12 100644
--- a/plugins/askrene/askrene.c
+++ b/plugins/askrene/askrene.c
@@ -8,6 +8,7 @@
  */
 #include "config.h"
 #include <ccan/array_size/array_size.h>
+#include <ccan/noerr/noerr.h>
 #include <ccan/tal/grab_file/grab_file.h>
 #include <ccan/tal/str/str.h>
 #include <common/clock_time.h>
@@ -24,7 +25,8 @@
 #include <math.h>
 #include <plugins/askrene/askrene.h>
 #include <plugins/askrene/child/additional_costs.h>
-#include <plugins/askrene/child/entry.h>
+#include <plugins/askrene/child/child.h>
+#include <plugins/askrene/child/child_log.h>
 #include <plugins/askrene/layer.h>
 #include <plugins/askrene/reserve.h>
 #include <sys/wait.h>
@@ -522,12 +524,11 @@ static struct command_result *do_getroutes(struct command *cmd,
 	bool include_fees;
 	const char *err;
 	struct timemono deadline;
-	int child_fd, log_fd;
+	int replyfds[2], logfds[2];
 	struct router_child *child;
 	const struct layer **layers;
 	s8 *biases;
 	fp16_t *capacities;
-	int ecode;
 
 	/* update the gossmap */
 	if (gossmap_refresh(askrene->gossmap)) {
@@ -625,31 +626,56 @@ static struct command_result *do_getroutes(struct command *cmd,
 	child->start = time_mono();
 	deadline = timemono_add(child->start,
 				time_from_sec(askrene->route_seconds));
-	child_fd = fork_router_child(askrene->gossmap,
-				     layers,
-				     biases,
-				     info->additional_costs,
-				     askrene->reserved,
-				     take(capacities),
-				     info->dev_algo == ALGO_SINGLE_PATH,
-				     deadline, srcnode, dstnode, info->amount,
-				     info->maxfee, info->finalcltv, info->maxdelay, info->maxparts,
-				     include_fees,
-				     cmd->id, cmd->filter, &log_fd, &child->pid);
-	/* Save this, as remove_localmods won't preserve it. */
-	ecode = errno;
-	/* We don't need this any more. */
-	gossmap_remove_localmods(askrene->gossmap, localmods);
 
-	if (child_fd == -1) {
-		err = tal_fmt(tmpctx, "failed to fork: %s", strerror(ecode));
-		gossmap_remove_localmods(askrene->gossmap, localmods);
+	if (pipe(replyfds) != 0) {
+		err = tal_fmt(tmpctx, "failed to create pipes: %s", strerror(errno));
+		goto fail_broken;
+	}
+	if (pipe(logfds) != 0) {
+		err = tal_fmt(tmpctx, "failed to create pipes: %s", strerror(errno));
+		close_noerr(replyfds[0]);
+		close_noerr(replyfds[1]);
+		goto fail_broken;
+	}
+	child->pid = fork();
+	if (child->pid < 0) {
+		err = tal_fmt(tmpctx, "failed to fork: %s", strerror(errno));
+		close_noerr(replyfds[0]);
+		close_noerr(replyfds[1]);
+		close_noerr(logfds[0]);
+		close_noerr(logfds[1]);
 		goto fail_broken;
 	}
 
-	child->reply_conn = io_new_conn(child, child_fd,
+	if (child->pid == 0) {
+		/* We are the child.  Run the algo */
+		close(logfds[0]);
+		close(replyfds[0]);
+		set_child_log_fd(logfds[1]);
+
+		/* Does not return! */
+		run_child(askrene->gossmap,
+			  layers,
+			  biases,
+			  info->additional_costs,
+			  askrene->reserved,
+			  take(capacities),
+			  info->dev_algo == ALGO_SINGLE_PATH,
+			  deadline, srcnode, dstnode, info->amount,
+			  info->maxfee, info->finalcltv, info->maxdelay, info->maxparts,
+			  include_fees,
+			  cmd->id, cmd->filter, replyfds[1]);
+		abort();
+	}
+
+	close(logfds[1]);
+	close(replyfds[1]);
+
+	/* We don't need this any more. */
+	gossmap_remove_localmods(askrene->gossmap, localmods);
+	child->reply_conn = io_new_conn(child, replyfds[0],
 					child_reply_init, child);
-	child->log_conn = io_new_conn(child, log_fd, child_log_init, child);
+	child->log_conn = io_new_conn(child, logfds[0], child_log_init, child);
 	child->cmd = cmd;
 
 	list_add_tail(&askrene->children, &child->list);
diff --git a/plugins/askrene/child/child.c b/plugins/askrene/child/child.c
new file mode 100644
index 00000000..8a4363d5
--- /dev/null
+++ b/plugins/askrene/child/child.c
@@ -0,0 +1,278 @@
+#include "config.h"
+#include <assert.h>
+#include <ccan/json_out/json_out.h>
+#include <ccan/read_write_all/read_write_all.h>
+#include <ccan/tal/str/str.h>
+#include <common/json_stream.h>
+#include <common/route.h>
+#include <common/utils.h>
+#include <plugins/askrene/child/child.h>
+#include <plugins/askrene/child/child_log.h>
+#include <plugins/askrene/child/flow.h>
+#include <plugins/askrene/child/mcf.h>
+#include <plugins/askrene/child/route_query.h>
+
+/* A single route. */
+struct route {
+	/* Actual path to take */
+	struct route_hop *hops;
+	/* Probability estimate (0-1) */
+	double success_prob;
+};
+
+static const char *fmt_route(const tal_t *ctx,
+			     const struct route *route,
+			     struct amount_msat delivers,
+			     u32 final_cltv)
+{
+	char *str = tal_strdup(ctx, "");
+
+	for (size_t i = 0; i < tal_count(route->hops); i++) {
+		struct short_channel_id_dir scidd;
+		scidd.scid = route->hops[i].scid;
+		scidd.dir = route->hops[i].direction;
+		tal_append_fmt(&str, "%s/%u %s -> ",
+			       fmt_amount_msat(tmpctx, route->hops[i].amount),
+			       route->hops[i].delay,
+			       fmt_short_channel_id_dir(tmpctx, &scidd));
+	}
+	tal_append_fmt(&str, "%s/%u",
+		       fmt_amount_msat(tmpctx, delivers), final_cltv);
+	return str;
+}
+
+/* Convert back into routes, with delay and other information fixed */
+static struct route **convert_flows_to_routes(const tal_t *ctx,
+					      struct route_query *rq,
+					      u32 finalcltv,
+					      struct flow **flows,
+					      struct amount_msat **amounts,
+					      bool include_fees)
+{
+	struct route **routes;
+	routes = tal_arr(ctx, struct route *, tal_count(flows));
+	*amounts = tal_arr(ctx, struct amount_msat, tal_count(flows));
+
+	for (size_t i = 0; i < tal_count(flows); i++) {
+		struct route *r;
+		struct amount_msat msat;
+		u32 delay;
+
+		routes[i] = r = tal(routes, struct route);
+		r->success_prob = flow_probability(flows[i], rq);
+		r->hops = tal_arr(r, struct route_hop, tal_count(flows[i]->path));
+
+		msat = flows[i]->delivers;
+		delay = finalcltv;
+
+		if (!include_fees) {
+			/* Fill in backwards to calc amount and delay */
+			for (int j = tal_count(flows[i]->path) - 1; j >= 0;
+			     j--) {
+				struct route_hop *rh = &r->hops[j];
+				struct gossmap_node *far_end;
+				const struct half_chan *h =
+				    flow_edge(flows[i], j);
+
+				if (!amount_msat_add_fee(&msat, h->base_fee,
+							 h->proportional_fee))
+					abort();
+				delay += h->delay;
+
+				rh->scid = gossmap_chan_scid(rq->gossmap,
+							     flows[i]->path[j]);
+				rh->direction = flows[i]->dirs[j];
+				far_end = gossmap_nth_node(rq->gossmap,
+							   flows[i]->path[j],
+							   !flows[i]->dirs[j]);
+				gossmap_node_get_id(rq->gossmap, far_end,
+						    &rh->node_id);
+				rh->amount = msat;
+				rh->delay = delay;
+			}
+		        (*amounts)[i] = flows[i]->delivers;
+		} else {
+			/* Fill in backwards to calc delay */
+			for (int j = tal_count(flows[i]->path) - 1; j >= 0;
+			     j--) {
+				struct route_hop *rh = &r->hops[j];
+				struct gossmap_node *far_end;
+				const struct half_chan *h =
+				    flow_edge(flows[i], j);
+
+				delay += h->delay;
+
+				rh->scid = gossmap_chan_scid(rq->gossmap,
+							     flows[i]->path[j]);
+				rh->direction = flows[i]->dirs[j];
+				far_end = gossmap_nth_node(rq->gossmap,
+							   flows[i]->path[j],
+							   !flows[i]->dirs[j]);
+				gossmap_node_get_id(rq->gossmap, far_end,
+						    &rh->node_id);
+				rh->delay = delay;
+			}
+			/* Compute fees forward */
+			for (int j = 0; j < tal_count(flows[i]->path); j++) {
+				struct route_hop *rh = &r->hops[j];
+				const struct half_chan *h =
+				    flow_edge(flows[i], j);
+
+				rh->amount = msat;
+                                msat = amount_msat_sub_fee(msat, h->base_fee,
+							   h->proportional_fee);
+			}
+		        (*amounts)[i] = msat;
+		}
+
+		child_log(tmpctx, LOG_INFORM, "Flow %zu/%zu: %s",
+			  i, tal_count(flows),
+			  fmt_route(tmpctx, r, (*amounts)[i], finalcltv));
+	}
+
+	return routes;
+}
+
+static void json_add_getroutes(struct json_stream *js,
+			       struct route **routes,
+			       const struct amount_msat *amounts,
+			       double probability,
+			       u32 final_cltv)
+{
+	json_add_u64(js, "probability_ppm", (u64)(probability * 1000000));
+	json_array_start(js, "routes");
+	for (size_t i = 0; i < tal_count(routes); i++) {
+		json_object_start(js, NULL);
+		json_add_u64(js, "probability_ppm",
+			     (u64)(routes[i]->success_prob * 1000000));
+		json_add_amount_msat(js, "amount_msat", amounts[i]);
+		json_add_u32(js, "final_cltv", final_cltv);
+		json_array_start(js, "path");
+		for (size_t j = 0; j < tal_count(routes[i]->hops); j++) {
+			struct short_channel_id_dir scidd;
+			const struct route_hop *r = &routes[i]->hops[j];
+			json_object_start(js, NULL);
+			scidd.scid = r->scid;
+			scidd.dir = r->direction;
+			json_add_short_channel_id_dir(
+			    js, "short_channel_id_dir", scidd);
+			json_add_node_id(js, "next_node_id", &r->node_id);
+			json_add_amount_msat(js, "amount_msat", r->amount);
+			json_add_u32(js, "delay", r->delay);
+			json_object_end(js);
+		}
+		json_array_end(js);
+		json_object_end(js);
+	}
+	json_array_end(js);
+}
+
+
+static struct route_query *new_route_query(const tal_t *ctx,
+					   const struct gossmap *gossmap,
+					   const char *cmd_id,
+					   const struct layer **layers,
+					   const s8 *biases,
+					   const struct additional_cost_htable *additional_costs,
+					   struct reserve_htable *reserved,
+					   fp16_t *capacities TAKES)
+{
+	struct route_query *rq = tal(ctx, struct route_query);
+
+	rq->gossmap = gossmap;
+	rq->cmd_id = tal_strdup(rq, cmd_id);
+	rq->layers = layers;
+	rq->biases = biases;
+	rq->additional_costs = additional_costs;
+	rq->reserved = reserved;
+	rq->capacities = tal_dup_talarr(rq, fp16_t, capacities);
+	rq->disabled_chans =
+	    tal_arrz(rq, bitmap,
+		     2 * BITMAP_NWORDS(gossmap_max_chan_idx(gossmap)));
+
+	return rq;
+}
+
+void run_child(const struct gossmap *gossmap,
+	       const struct layer **layers,
+	       const s8 *biases,
+	       const struct additional_cost_htable *additional_costs,
+	       struct reserve_htable *reserved,
+	       fp16_t *capacities TAKES,
+	       bool single_path,
+	       struct timemono deadline,
+	       const struct gossmap_node *srcnode,
+	       const struct gossmap_node *dstnode,
+	       struct amount_msat amount, struct amount_msat maxfee,
+	       u32 finalcltv, u32 maxdelay, size_t maxparts,
+              bool include_fees,
+	       const char *cmd_id,
+	       struct json_filter *cmd_filter,
+	       int replyfd)
+{
+	double probability;
+	struct flow **flows;
+	struct route **routes;
+	struct amount_msat *amounts;
+	const char *err, *p;
+	size_t len;
+	struct route_query *rq;
+
+	/* We exit below, so we don't bother freeing this */
+	rq = new_route_query(NULL, gossmap, cmd_id, layers,
+			     biases, additional_costs,
+			     reserved, capacities);
+	if (single_path) {
+		err = single_path_routes(rq, rq, deadline, srcnode, dstnode,
+					 amount, maxfee, finalcltv,
+					 maxdelay, &flows, &probability);
+	} else {
+		err = default_routes(rq, rq, deadline, srcnode, dstnode,
+				     amount, maxfee, finalcltv, maxdelay,
+				     maxparts, &flows, &probability);
+	}
+	if (err) {
+		write_all(replyfd, err, strlen(err));
+		/* Non-zero exit tells parent this is an error string. */
+		exit(1);
+	}
+
+	/* otherwise we continue */
+	assert(tal_count(flows) > 0);
+	child_log(tmpctx, LOG_DBG, "Final answer has %zu flows",
+		  tal_count(flows));
+
+	/* convert flows to routes */
+	routes = convert_flows_to_routes(rq, rq, finalcltv, flows,
+					 &amounts, include_fees);
+	assert(tal_count(routes) == tal_count(flows));
+	assert(tal_count(amounts) == tal_count(flows));
+
+	/* output the results */
+	struct json_stream *js = new_json_stream(tmpctx, NULL, NULL);
+	json_object_start(js, NULL);
+	json_add_string(js, "jsonrpc", "2.0");
+	json_add_id(js, cmd_id);
+	json_object_start(js, "result");
+	if (cmd_filter)
+		json_stream_attach_filter(js, cmd_filter);
+	json_add_getroutes(js, routes, amounts, probability, finalcltv);
+
+	/* Detach filter before it complains about closing object it never saw */
+	if (cmd_filter) {
+		err = json_stream_detach_filter(tmpctx, js);
+		if (err)
+			json_add_string(js, "warning_parameter_filter", err);
+	}
+	/* "result" object */
+	json_object_end(js);
+	/* Global object */
+	json_object_end(js);
+	json_stream_close(js, NULL);
+
+	p = json_out_contents(js->jout, &len);
+	if (!write_all(replyfd, p, len))
+		abort();
+	exit(0);
+}
+
diff --git a/plugins/askrene/child/child.h b/plugins/askrene/child/child.h
new file mode 100644
index 00000000..847bda99
--- /dev/null
+++ b/plugins/askrene/child/child.h
@@ -0,0 +1,36 @@
+#ifndef LIGHTNING_PLUGINS_ASKRENE_CHILD_CHILD_H
+#define LIGHTNING_PLUGINS_ASKRENE_CHILD_CHILD_H
+#include "config.h"
+#include <ccan/compiler/compiler.h>
+#include <ccan/short_types/short_types.h>
+#include <ccan/time/time.h>
+#include <common/amount.h>
+#include <common/fp16.h>
+#include <stdbool.h>
+
+struct additional_cost_htable;
+struct gossmap;
+struct json_filter;
+struct layer;
+struct reserve_htable;
+
+/* This is the child.  Do the thing. */
+void run_child(const struct gossmap *gossmap,
+	       const struct layer **layers,
+	       const s8 *biases,
+	       const struct additional_cost_htable *additional_costs,
+	       struct reserve_htable *reserved,
+	       fp16_t *capacities TAKES,
+	       bool single_path,
+	       struct timemono deadline,
+	       const struct gossmap_node *srcnode,
+	       const struct gossmap_node *dstnode,
+	       struct amount_msat amount, struct amount_msat maxfee,
+	       u32 finalcltv, u32 maxdelay, size_t maxparts,
+	       bool include_fees,
+	       const char *cmd_id,
+	       struct json_filter *cmd_filter,
+	       int reply_fd) NORETURN;
+
+#endif /* LIGHTNING_PLUGINS_ASKRENE_CHILD_CHILD_H */
+
diff --git a/plugins/askrene/child/entry.c b/plugins/askrene/child/entry.c
deleted file mode 100644
index 92dddd1a..00000000
--- a/plugins/askrene/child/entry.c
+++ /dev/null
@@ -1,317 +0,0 @@
-#include "config.h"
-#include <assert.h>
-#include <ccan/json_out/json_out.h>
-#include <ccan/noerr/noerr.h>
-#include <ccan/read_write_all/read_write_all.h>
-#include <ccan/tal/str/str.h>
-#include <common/json_stream.h>
-#include <common/route.h>
-#include <common/utils.h>
-#include <plugins/askrene/child/child_log.h>
-#include <plugins/askrene/child/entry.h>
-#include <plugins/askrene/child/flow.h>
-#include <plugins/askrene/child/mcf.h>
-#include <plugins/askrene/child/route_query.h>
-#include <unistd.h>
-
-/* A single route. */
-struct route {
-	/* Actual path to take */
-	struct route_hop *hops;
-	/* Probability estimate (0-1) */
-	double success_prob;
-};
-
-static const char *fmt_route(const tal_t *ctx,
-			     const struct route *route,
-			     struct amount_msat delivers,
-			     u32 final_cltv)
-{
-	char *str = tal_strdup(ctx, "");
-
-	for (size_t i = 0; i < tal_count(route->hops); i++) {
-		struct short_channel_id_dir scidd;
-		scidd.scid = route->hops[i].scid;
-		scidd.dir = route->hops[i].direction;
-		tal_append_fmt(&str, "%s/%u %s -> ",
-			       fmt_amount_msat(tmpctx, route->hops[i].amount),
-			       route->hops[i].delay,
-			       fmt_short_channel_id_dir(tmpctx, &scidd));
-	}
-	tal_append_fmt(&str, "%s/%u",
-		       fmt_amount_msat(tmpctx, delivers), final_cltv);
-	return str;
-}
-
-/* Convert back into routes, with delay and other information fixed */
-static struct route **convert_flows_to_routes(const tal_t *ctx,
-					      struct route_query *rq,
-					      u32 finalcltv,
-					      struct flow **flows,
-					      struct amount_msat **amounts,
-					      bool include_fees)
-{
-	struct route **routes;
-	routes = tal_arr(ctx, struct route *, tal_count(flows));
-	*amounts = tal_arr(ctx, struct amount_msat, tal_count(flows));
-
-	for (size_t i = 0; i < tal_count(flows); i++) {
-		struct route *r;
-		struct amount_msat msat;
-		u32 delay;
-
-		routes[i] = r = tal(routes, struct route);
-		r->success_prob = flow_probability(flows[i], rq);
-		r->hops = tal_arr(r, struct route_hop, tal_count(flows[i]->path));
-
-		msat = flows[i]->delivers;
-		delay = finalcltv;
-
-		if (!include_fees) {
-			/* Fill in backwards to calc amount and delay */
-			for (int j = tal_count(flows[i]->path) - 1; j >= 0;
-			     j--) {
-				struct route_hop *rh = &r->hops[j];
-				struct gossmap_node *far_end;
-				const struct half_chan *h =
-				    flow_edge(flows[i], j);
-
-				if (!amount_msat_add_fee(&msat, h->base_fee,
-							 h->proportional_fee))
-					abort();
-				delay += h->delay;
-
-				rh->scid = gossmap_chan_scid(rq->gossmap,
-							     flows[i]->path[j]);
-				rh->direction = flows[i]->dirs[j];
-				far_end = gossmap_nth_node(rq->gossmap,
-							   flows[i]->path[j],
-							   !flows[i]->dirs[j]);
-				gossmap_node_get_id(rq->gossmap, far_end,
-						    &rh->node_id);
-				rh->amount = msat;
-				rh->delay = delay;
-			}
-		        (*amounts)[i] = flows[i]->delivers;
-		} else {
-			/* Fill in backwards to calc delay */
-			for (int j = tal_count(flows[i]->path) - 1; j >= 0;
-			     j--) {
-				struct route_hop *rh = &r->hops[j];
-				struct gossmap_node *far_end;
-				const struct half_chan *h =
-				    flow_edge(flows[i], j);
-
-				delay += h->delay;
-
-				rh->scid = gossmap_chan_scid(rq->gossmap,
-							     flows[i]->path[j]);
-				rh->direction = flows[i]->dirs[j];
-				far_end = gossmap_nth_node(rq->gossmap,
-							   flows[i]->path[j],
-							   !flows[i]->dirs[j]);
-				gossmap_node_get_id(rq->gossmap, far_end,
-						    &rh->node_id);
-				rh->delay = delay;
-			}
-			/* Compute fees forward */
-			for (int j = 0; j < tal_count(flows[i]->path); j++) {
-				struct route_hop *rh = &r->hops[j];
-				const struct half_chan *h =
-				    flow_edge(flows[i], j);
-
-				rh->amount = msat;
-                                msat = amount_msat_sub_fee(msat, h->base_fee,
-							   h->proportional_fee);
-			}
-		        (*amounts)[i] = msat;
-		}
-
-		child_log(tmpctx, LOG_INFORM, "Flow %zu/%zu: %s",
-			  i, tal_count(flows),
-			  fmt_route(tmpctx, r, (*amounts)[i], finalcltv));
-	}
-
-	return routes;
-}
-
-static void json_add_getroutes(struct json_stream *js,
-			       struct route **routes,
-			       const struct amount_msat *amounts,
-			       double probability,
-			       u32 final_cltv)
-{
-	json_add_u64(js, "probability_ppm", (u64)(probability * 1000000));
-	json_array_start(js, "routes");
-	for (size_t i = 0; i < tal_count(routes); i++) {
-		json_object_start(js, NULL);
-		json_add_u64(js, "probability_ppm",
-			     (u64)(routes[i]->success_prob * 1000000));
-		json_add_amount_msat(js, "amount_msat", amounts[i]);
-		json_add_u32(js, "final_cltv", final_cltv);
-		json_array_start(js, "path");
-		for (size_t j = 0; j < tal_count(routes[i]->hops); j++) {
-			struct short_channel_id_dir scidd;
-			const struct route_hop *r = &routes[i]->hops[j];
-			json_object_start(js, NULL);
-			scidd.scid = r->scid;
-			scidd.dir = r->direction;
-			json_add_short_channel_id_dir(
-			    js, "short_channel_id_dir", scidd);
-			json_add_node_id(js, "next_node_id", &r->node_id);
-			json_add_amount_msat(js, "amount_msat", r->amount);
-			json_add_u32(js, "delay", r->delay);
-			json_object_end(js);
-		}
-		json_array_end(js);
-		json_object_end(js);
-	}
-	json_array_end(js);
-}
-
-
-static struct route_query *new_route_query(const tal_t *ctx,
-					   const struct gossmap *gossmap,
-					   const char *cmd_id,
-					   const struct layer **layers,
-					   const s8 *biases,
-					   const struct additional_cost_htable *additional_costs,
-					   struct reserve_htable *reserved,
-					   fp16_t *capacities TAKES)
-{
-	struct route_query *rq = tal(ctx, struct route_query);
-
-	rq->gossmap = gossmap;
-	rq->cmd_id = tal_strdup(rq, cmd_id);
-	rq->layers = layers;
-	rq->biases = biases;
-	rq->additional_costs = additional_costs;
-	rq->reserved = reserved;
-	rq->capacities = tal_dup_talarr(rq, fp16_t, capacities);
-	rq->disabled_chans =
-	    tal_arrz(rq, bitmap,
-		     2 * BITMAP_NWORDS(gossmap_max_chan_idx(gossmap)));
-
-	return rq;
-}
-
-/* Returns fd to child */
-int fork_router_child(const struct gossmap *gossmap,
-		      const struct layer **layers,
-		      const s8 *biases,
-		      const struct additional_cost_htable *additional_costs,
-		      struct reserve_htable *reserved,
-		      fp16_t *capacities TAKES,
-		      bool single_path,
-		      struct timemono deadline,
-		      const struct gossmap_node *srcnode,
-		      const struct gossmap_node *dstnode,
-		      struct amount_msat amount, struct amount_msat maxfee,
-		      u32 finalcltv, u32 maxdelay, size_t maxparts,
-		      bool include_fees,
-		      const char *cmd_id,
-		      struct json_filter *cmd_filter,
-		      int *log_fd,
-		      int *child_pid)
-{
-	int replyfds[2], logfds[2];
-	double probability;
-	struct flow **flows;
-	struct route **routes;
-	struct amount_msat *amounts;
-	const char *err, *p;
-	size_t len;
-	struct route_query *rq;
-
-	if (pipe(replyfds) != 0)
-		goto parent_fail;
-	if (pipe(logfds) != 0) {
-		close_noerr(replyfds[0]);
-		close_noerr(replyfds[1]);
-		goto parent_fail;
-	}
-	*child_pid = fork();
-	if (*child_pid < 0) {
-		close_noerr(replyfds[0]);
-		close_noerr(replyfds[1]);
-		close_noerr(logfds[0]);
-		close_noerr(logfds[1]);
-		goto parent_fail;
-	}
-	if (*child_pid != 0) {
-		close(logfds[1]);
-		close(replyfds[1]);
-		*log_fd = logfds[0];
-		if (taken(capacities))
-			tal_free(capacities);
-		return replyfds[0];
-	}
-
-	/* We are the child.  Run the algo */
-	close(logfds[0]);
-	close(replyfds[0]);
-	set_child_log_fd(logfds[1]);
-
-	/* We exit below, so we don't bother freeing this */
-	rq = new_route_query(NULL, gossmap, cmd_id, layers,
-			     biases, additional_costs,
-			     reserved, capacities);
-	if (single_path) {
-		err = single_path_routes(rq, rq, deadline, srcnode, dstnode,
-					 amount, maxfee, finalcltv,
-					 maxdelay, &flows, &probability);
-	} else {
-		err = default_routes(rq, rq, deadline, srcnode, dstnode,
-				     amount, maxfee, finalcltv, maxdelay,
-				     maxparts, &flows, &probability);
-	}
-	if (err) {
-		write_all(replyfds[1], err, strlen(err));
-		/* Non-zero exit tells parent this is an error string. */
-		exit(1);
-	}
-
-	/* otherwise we continue */
-	assert(tal_count(flows) > 0);
-	child_log(tmpctx, LOG_DBG, "Final answer has %zu flows",
-		  tal_count(flows));
-
-	/* convert flows to routes */
-	routes = convert_flows_to_routes(rq, rq, finalcltv, flows,
-					 &amounts, include_fees);
-	assert(tal_count(routes) == tal_count(flows));
-	assert(tal_count(amounts) == tal_count(flows));
-
-	/* output the results */
-	struct json_stream *js = new_json_stream(tmpctx, NULL, NULL);
-	json_object_start(js, NULL);
-	json_add_string(js, "jsonrpc", "2.0");
-	json_add_id(js, cmd_id);
-	json_object_start(js, "result");
-	if (cmd_filter)
-		json_stream_attach_filter(js, cmd_filter);
-	json_add_getroutes(js, routes, amounts, probability, finalcltv);
-
-	/* Detach filter before it complains about closing object it never saw */
-	if (cmd_filter) {
-		err = json_stream_detach_filter(tmpctx, js);
-		if (err)
-			json_add_string(js, "warning_parameter_filter", err);
-	}
-	/* "result" object */
-	json_object_end(js);
-	/* Global object */
-	json_object_end(js);
-	json_stream_close(js, NULL);
-
-	p = json_out_contents(js->jout, &len);
-	if (!write_all(replyfds[1], p, len))
-		abort();
-	exit(0);
-
-parent_fail:
-	if (taken(capacities))
-		tal_free(capacities);
-	return -1;
-}
-
diff --git a/plugins/askrene/child/entry.h b/plugins/askrene/child/entry.h
deleted file mode 100644
index 7484b609..00000000
--- a/plugins/askrene/child/entry.h
+++ /dev/null
@@ -1,35 +0,0 @@
-#ifndef LIGHTNING_PLUGINS_ASKRENE_CHILD_ENTRY_H
-#define LIGHTNING_PLUGINS_ASKRENE_CHILD_ENTRY_H
-#include "config.h"
-#include <ccan/short_types/short_types.h>
-#include <ccan/time/time.h>
-#include <common/amount.h>
-#include <common/fp16.h>
-#include <stdbool.h>
-
-struct route_query;
-struct gossmap_node;
-struct json_filter;
-struct layer;
-struct reserve_htable;
-struct additional_cost_htable;
-
-/* Entry point to the child process. */
-int fork_router_child(const struct gossmap *gossmap,
-		      const struct layer **layers,
-		      const s8 *biases,
-		      const struct additional_cost_htable *additional_costs,
-		      struct reserve_htable *reserved,
-		      fp16_t *capacities TAKES,
-		      bool single_path,
-		      struct timemono deadline,
-		      const struct gossmap_node *srcnode,
-		      const struct gossmap_node *dstnode,
-		      struct amount_msat amount, struct amount_msat maxfee,
-		      u32 finalcltv, u32 maxdelay, size_t maxparts,
-		      bool include_fees,
-		      const char *cmd_id,
-		      struct json_filter *cmd_filter,
-		      int *log_fd,
-		      int *child_pid);
-#endif /* LIGHTNING_PLUGINS_ASKRENE_CHILD_ENTRY_H */