From 324fdcfd583dbd95ce479712be57c6ca93c29fbb Mon Sep 17 00:00:00 2001
From: tiptorrent development team <tiptorrent@soleta.eu>
Date: Thu, 23 Sep 2021 22:05:20 +0200
Subject: runtime split original file into chunks

No need to split the original file on the server side.
---
 src/core.c    |  1 +
 src/core.h    |  4 ++++
 src/handler.c | 74 +++++++++++++++++++++++++++++++++++++++++++++++++++++++----
 3 files changed, 74 insertions(+), 5 deletions(-)

diff --git a/src/core.c b/src/core.c
index ff471cc..8caabec 100644
--- a/src/core.c
+++ b/src/core.c
@@ -471,6 +471,7 @@ void tip_server_accept_cb(struct ev_loop *loop, struct ev_io *io, int events)
 	}
 	memcpy(&cli->addr, &client_addr, sizeof(client_addr));
 	cli->fd = -1;
+	cli->chunk = -1;
 
 	syslog(LOG_ERR, "accepting client connection from %s:%hu",
 	       inet_ntoa(cli->addr.sin_addr), htons(cli->addr.sin_port));
diff --git a/src/core.h b/src/core.h
index 36fb205..0a82d2e 100644
--- a/src/core.h
+++ b/src/core.h
@@ -6,6 +6,8 @@
 #include <stdbool.h>
 #include <netinet/in.h>
 
+#define MAX_CHUNKS 4
+
 #define TIP_MSG_REQUEST_MAXLEN	 131072
 
 extern const char *root;
@@ -48,7 +50,9 @@ struct tip_client {
 	enum tip_http_method	method;
 	const char		*uri;
 	const char		*path;
+	uint32_t		chunk;
 	off_t			size;
+	off_t			left;
 	int			fd;
 	off_t			offset;
 
diff --git a/src/handler.c b/src/handler.c
index 54c2c1b..f3ce8ec 100644
--- a/src/handler.c
+++ b/src/handler.c
@@ -59,6 +59,7 @@ int tip_client_state_process_payload(struct tip_client *cli)
 	char _uri[32], *uri = _uri;
 	char allow_redirect_str[5];
 	char path[PATH_MAX + 1];
+	char *chunk = NULL;
 	struct stat st;
 	int err;
 
@@ -93,14 +94,37 @@ int tip_client_state_process_payload(struct tip_client *cli)
 	if (!sanitize(uri))
 		return tip_client_method_not_found(cli);
 
+	/* skip initial / */
+	uri++;
+
+	switch (cli->method) {
+	case TIP_METHOD_GET:
+	case TIP_METHOD_POST:
+		/* get chunk number from file extension, e.g. FILE.0 */
+		chunk = strchr(uri, '.');
+		if (chunk) {
+			*chunk = '\0';
+			chunk++;
+			cli->chunk = atoi(chunk);
+			if (cli->chunk >= MAX_CHUNKS)
+				return tip_client_file_not_found(cli);
+		}
+		break;
+	case TIP_METHOD_HEAD:
+		break;
+	}
+
 	snprintf(path, PATH_MAX, "%s/%s", root, uri);
 
 	err = stat(path, &st);
 	if (err < 0)
 		return tip_client_file_not_found(cli);
 
-	/* skip initial / */
-	uri++;
+	/* restore the original uri that was mangled. */
+	if (chunk) {
+		chunk--;
+		*chunk = '.';
+	}
 
 	cli->uri = strdup(uri);
 	cli->path = strdup(path);
@@ -139,6 +163,8 @@ int tip_client_state_process_payload(struct tip_client *cli)
 
 int tip_client_state_process_payload_reply(struct tip_client *cli)
 {
+	uint64_t chunk_size;
+	off_t chunk_offset;
 	char buf[1024];
 	int fd;
 
@@ -156,8 +182,35 @@ int tip_client_state_process_payload_reply(struct tip_client *cli)
 	if (fd < 0)
 		return tip_client_file_not_found(cli);
 
-	if (cli->method == TIP_METHOD_POST)
+	switch (cli->method) {
+	case TIP_METHOD_GET:
+		if (cli->chunk < 0)
+			break;
+
+		chunk_size = cli->size / MAX_CHUNKS;
+		if (cli->size % MAX_CHUNKS) {
+			if (cli->chunk < MAX_CHUNKS - 1) {
+				chunk_size++;
+				chunk_offset = chunk_size * cli->chunk;
+			} else {
+				chunk_offset = chunk_size * cli->chunk;
+				chunk_offset += MAX_CHUNKS - 1;
+				chunk_size--;
+			}
+		} else {
+			chunk_offset = chunk_size * cli->chunk;
+		}
+		cli->size = chunk_size;
+		cli->offset = chunk_offset;
+		break;
+	case TIP_METHOD_POST:
 		cli->size = 0;
+		break;
+	case TIP_METHOD_HEAD:
+		break;
+	}
+
+	cli->left = cli->size;
 
 	snprintf(buf, sizeof(buf),
 		 "HTTP/1.1 200 OK\r\nContent-Length: %lu\r\n\r\n",
@@ -181,10 +234,21 @@ int tip_client_state_process_payload_reply(struct tip_client *cli)
 
 int tip_client_state_process_payload_bulk(struct tip_client *cli)
 {
-	if (sendfile(tip_client_socket(cli), cli->fd, &cli->offset, BLOCK) < 0)
+	uint32_t bytes;
+	int ret;
+
+	if (cli->left < BLOCK)
+		bytes = cli->left;
+	else
+		bytes = BLOCK;
+
+	ret = sendfile(tip_client_socket(cli), cli->fd, &cli->offset, bytes);
+	if (ret < 0)
 		return -1;
 
-	if (cli->offset >= cli->size) {
+	cli->left -= ret;
+
+	if (cli->left <= 0) {
 		cli->state = TIP_CLIENT_CLOSE_WAIT;
 		return 1;
 	}
-- 
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