initial commit

11 files changed, 1152 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..9ffbbf4
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,64 @@
+# http://www.gnu.org/software/automake
+
+Makefile.in
+.deps/
+.dirstamp
+
+# http://www.gnu.org/software/autoconf
+
+autom4te.cache
+/autoscan.log
+/autoscan-*.log
+/aclocal.m4
+/compile
+/config.cache
+/config.guess
+/config.h.in
+/config.log
+/config.status
+/config.sub
+/configure
+/configure~
+/configure.scan
+/depcomp
+/install-sh
+/missing
+/stamp-h1
+/build-aux/
+
+# https://www.gnu.org/software/libtool/
+
+/ltmain.sh
+
+# http://www.gnu.org/software/texinfo
+
+/texinfo.tex
+
+# http://www.gnu.org/software/m4/
+
+m4/libtool.m4
+m4/ltoptions.m4
+m4/ltsugar.m4
+m4/ltversion.m4
+m4/lt~obsolete.m4
+
+# Generated Makefile
+# (meta build system like autotools,
+# can automatically generate from config.status script
+# (which is called by configure script))
+Makefile
+
+# Object files
+*.o
+*.ko
+*.obj
+*.elf
+
+# Executables
+tiptorrent
+
+# Debug files
+*.dSYM/
+*.su
+*.idb
+*.pdb
diff --git a/Makefile.am b/Makefile.am
new file mode 100644
index 0000000..2d76b49
--- /dev/null
+++ b/Makefile.am
@@ -0,0 +1,7 @@
+sbin_PROGRAMS = tiptorrent
+
+AM_CFLAGS  =  ${LIBEVENT_CFLAGS} -g -Wall
+
+tiptorrent_SOURCES = src/handler.c	\
+		     src/core.c		\
+		     src/main.c
diff --git a/README b/README
new file mode 100644
index 0000000..91b9f2b
--- /dev/null
+++ b/README
@@ -0,0 +1,21 @@
+1) Compile:
+
+	make
+
+2) Run (serving files in the local folder):
+
+	./tiptorrent
+
+3) Generate test file
+
+	dd if=/dev/random of=TEST
+	... ctrl-c whenever you like ...
+	md5sum TEST
+
+4) Test (on a different terminal)
+
+	wget http://localhost:9999/TEST
+
+   Now check that downloaded file is the same:
+
+	md5sum TEST
diff --git a/configure.ac b/configure.ac
new file mode 100644
index 0000000..7764022
--- /dev/null
+++ b/configure.ac
@@ -0,0 +1,23 @@
+AC_INIT(tiptorrent, 1.0, info@soleta.eu)
+AC_CONFIG_AUX_DIR([build-aux])
+AC_PREFIX_DEFAULT(/usr)
+
+AC_CANONICAL_HOST
+AC_CONFIG_MACRO_DIR([m4])
+AM_INIT_AUTOMAKE([-Wall foreign subdir-objects tar-pax no-dist-gzip dist-bzip2 1.6])
+
+m4_ifdef([AM_SILENT_RULES], [AM_SILENT_RULES([yes])])
+
+AC_PROG_CC
+AC_PROG_INSTALL
+AC_PROG_LN_S
+
+case "$host" in
+*-*-linux*) ;;
+*) AC_MSG_ERROR([Linux only, sorry!]);;
+esac
+
+AC_CHECK_LIB([ev], [ev_loop_new], , AC_MSG_ERROR([libev not found]))
+
+AC_CONFIG_FILES([Makefile])
+AC_OUTPUT
diff --git a/src/core.c b/src/core.c
new file mode 100644
index 0000000..2b64347
--- /dev/null
+++ b/src/core.c
@@ -0,0 +1,440 @@
+/*
+ * Copyright (C) 2020-2021 Soleta Networks <info@soleta.eu>
+ *
+ * This program is free software: you can redistribute it and/or modify it under
+ * the terms of the GNU Affero General Public License as published by the
+ * Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ */
+
+#include "core.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <syslog.h>
+#include <sys/ioctl.h>
+#include <netinet/in.h>
+#include <ifaddrs.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <netinet/tcp.h>
+#include <fcntl.h>
+#include <time.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <errno.h>
+
+struct ev_loop *tip_main_loop;
+
+int num_clients;
+static LIST_HEAD(client_list);
+static LIST_HEAD(client_redirect_list);
+
+static void tip_client_activate_pending(void);
+
+static void tip_client_release(struct ev_loop *loop, struct tip_client *cli)
+{
+	syslog(LOG_INFO, "closing connection with %s:%hu",
+	       inet_ntoa(cli->addr.sin_addr), htons(cli->addr.sin_port));
+
+	list_del(&cli->list);
+	ev_io_stop(loop, &cli->io);
+	close(cli->io.fd);
+	if (cli->fd > 0)
+		close(cli->fd);
+
+	free((void *)cli->uri);
+	free((void *)cli->path);
+	free(cli);
+	num_clients--;
+
+	tip_client_activate_pending();
+}
+
+static int tip_client_payload_too_large(struct tip_client *cli)
+{
+	char buf[] = "HTTP/1.1 413 Payload Too Large\r\n"
+		     "Content-Length: 0\r\n\r\n";
+
+	send(tip_client_socket(cli), buf, strlen(buf), 0);
+
+	return -1;
+}
+
+static int tip_client_state_recv_hdr(struct tip_client *cli)
+{
+	char *ptr;
+
+	ptr = strstr(cli->buf, "\r\n\r\n");
+	if (!ptr)
+		return 0;
+
+	cli->msg_len = ptr - cli->buf + 4;
+
+	ptr = strstr(cli->buf, "Content-Length: ");
+	if (ptr) {
+		sscanf(ptr, "Content-Length: %i[^\r\n]", &cli->content_length);
+		if (cli->content_length < 0)
+			return -1;
+		cli->msg_len += cli->content_length;
+	}
+
+	ptr = strstr(cli->buf, "Authorization: ");
+	if (ptr)
+		sscanf(ptr, "Authorization: %63[^\r\n]", cli->auth_token);
+
+	return 1;
+}
+
+static int tip_client_recv(struct tip_client *cli, int events)
+{
+	struct ev_io *io = &cli->io;
+	int ret;
+
+	ret = recv(io->fd, cli->buf + cli->buf_len,
+		   sizeof(cli->buf) - cli->buf_len, 0);
+	if (ret <= 0) {
+		if (ret < 0) {
+			syslog(LOG_ERR, "error reading from client %s:%hu (%s)\n",
+			       inet_ntoa(cli->addr.sin_addr), ntohs(cli->addr.sin_port),
+			       strerror(errno));
+		}
+		return ret;
+	}
+
+	return ret;
+}
+
+static void tip_client_read_cb(struct ev_loop *loop, struct ev_io *io, int events)
+{
+	struct tip_client *cli;
+	int ret;
+
+	cli = container_of(io, struct tip_client, io);
+
+	ret = tip_client_recv(cli, events);
+	if (ret <= 0)
+		goto close;
+
+	ev_timer_again(loop, &cli->timer);
+
+	cli->buf_len += ret;
+	if (cli->buf_len >= sizeof(cli->buf)) {
+		syslog(LOG_ERR, "client request from %s:%hu is too long\n",
+		       inet_ntoa(cli->addr.sin_addr), ntohs(cli->addr.sin_port));
+		tip_client_payload_too_large(cli);
+		goto close;
+	}
+
+	switch (cli->state) {
+	case TIP_CLIENT_RECEIVING_HEADER:
+		ret = tip_client_state_recv_hdr(cli);
+		if (ret < 0)
+			goto close;
+		if (!ret)
+			return;
+
+		cli->state = TIP_CLIENT_RECEIVING_PAYLOAD;
+		/* Fall through. */
+	case TIP_CLIENT_RECEIVING_PAYLOAD:
+		/* Still not enough data to process request. */
+		if (cli->buf_len < cli->msg_len)
+			return;
+
+		cli->state = TIP_CLIENT_PROCESSING_REQUEST;
+		/* fall through. */
+	case TIP_CLIENT_PROCESSING_REQUEST:
+		ret = tip_client_state_process_payload(cli);
+		if (ret > 0) {
+			/* client is pending. */
+			return;
+		} else if (ret < 0) {
+			syslog(LOG_ERR, "Failed to process HTTP request from %s:%hu\n",
+			       inet_ntoa(cli->addr.sin_addr),
+			       ntohs(cli->addr.sin_port));
+			goto close;
+		}
+
+		ev_io_stop(loop, &cli->io);
+		ev_io_set(&cli->io, tip_client_socket(cli), EV_READ | EV_WRITE);
+		ev_io_start(loop, &cli->io);
+		break;
+	default:
+		syslog(LOG_ERR, "unknown read state, critical internal error\n");
+		goto close;
+	}
+	return;
+close:
+	ev_timer_stop(loop, &cli->timer);
+	tip_client_release(loop, cli);
+}
+
+static void tip_client_redirect_timer_cb(struct ev_loop *loop, ev_timer *timer,
+					int events)
+{
+	struct tip_client_redirect *redir;
+
+	redir = container_of(timer, struct tip_client_redirect, timer);
+
+	syslog(LOG_ERR, "timeout for client redirection to %s:%hu for %s\n",
+	       inet_ntoa(redir->addr.sin_addr), ntohs(redir->addr.sin_port),
+	       redir->uri);
+
+	list_del(&redir->list);
+	free((void *)redir->uri);
+	free(redir);
+}
+
+static int tip_client_redirect_create(const struct tip_client *cli)
+{
+	struct tip_client_redirect *redir;
+	bool found = false;
+
+	if (!redirect || !cli->allow_redirect)
+		return 0;
+
+	list_for_each_entry(redir, &client_redirect_list, list) {
+		if (!strcmp(redir->uri, cli->uri) &&
+		    redir->addr.sin_addr.s_addr == cli->addr.sin_addr.s_addr) {
+			found = true;
+			break;
+		}
+	}
+
+	if (found) {
+		syslog(LOG_INFO, "client redirection to %s:%hu for %s already exists, skipping",
+		       inet_ntoa(cli->addr.sin_addr), htons(cli->addr.sin_port),
+		       cli->uri);
+		return 0;
+	}
+
+	redir = calloc(1, sizeof(struct tip_client_redirect));
+	if (!redir)
+		return -1;
+
+	redir->addr = cli->addr;
+	redir->addr.sin_port = htons(9999);
+	redir->uri = strdup(cli->uri);
+	list_add_tail(&redir->list, &client_redirect_list);
+
+	ev_timer_init(&redir->timer, tip_client_redirect_timer_cb, 60, 0.);
+	ev_timer_start(tip_main_loop, &redir->timer);
+
+	syslog(LOG_INFO, "adding client redirection to %s:%hu for %s",
+	       inet_ntoa(redir->addr.sin_addr), htons(redir->addr.sin_port),
+	       redir->uri);
+
+	return 0;
+}
+
+static void tip_client_write_cb(struct ev_loop *loop, struct ev_io *io, int events)
+{
+	struct tip_client *cli;
+	int ret;
+
+	cli = container_of(io, struct tip_client, io);
+
+	ev_timer_again(loop, &cli->timer);
+
+	switch (cli->state) {
+	case TIP_CLIENT_PROCESSING_REQUEST_2:
+		ret = tip_client_state_process_payload_reply(cli);
+		if (ret > 0) {
+			goto close;
+		} else if (ret < 0) {
+			syslog(LOG_ERR, "Failed to process HTTP request from %s:%hu\n",
+			       inet_ntoa(cli->addr.sin_addr),
+			       ntohs(cli->addr.sin_port));
+			goto close;
+		}
+		break;
+	case TIP_CLIENT_PROCESSING_REQUEST_3:
+		ret = tip_client_state_process_payload_bulk(cli);
+		if (ret > 0)
+			goto shutdown;
+		else if (ret < 0) {
+			syslog(LOG_ERR, "Failed to process HTTP request from %s:%hu\n",
+			       inet_ntoa(cli->addr.sin_addr),
+			       ntohs(cli->addr.sin_port));
+			goto close;
+		}
+		break;
+	default:
+		syslog(LOG_ERR, "unknown write state, critical internal error\n");
+		goto close;
+	}
+	return;
+shutdown:
+	if (cli->size > FILE_SIZE_THRESHOLD)
+		tip_client_redirect_create(cli);
+close:
+	ev_timer_stop(loop, &cli->timer);
+	tip_client_release(loop, cli);
+}
+
+static void tip_client_cb(struct ev_loop *loop, struct ev_io *io, int events)
+{
+	if (events & EV_READ)
+		return tip_client_read_cb(loop, io, events);
+	if (events & EV_WRITE)
+		return tip_client_write_cb(loop, io, events);
+}
+
+static void tip_client_timer_cb(struct ev_loop *loop, ev_timer *timer, int events)
+{
+	struct tip_client *cli;
+
+	cli = container_of(timer, struct tip_client, timer);
+
+	syslog(LOG_ERR, "timeout request for client %s:%hu\n",
+	       inet_ntoa(cli->addr.sin_addr), ntohs(cli->addr.sin_port));
+
+	tip_client_release(loop, cli);
+}
+
+/* Shut down connection if there is no data after 15 seconds. */
+#define TIP_CLIENT_TIMEOUT       15
+
+static void tip_client_start(struct tip_client *cli)
+{
+	cli->state = TIP_CLIENT_RECEIVING_HEADER;
+	ev_io_start(tip_main_loop, &cli->io);
+	ev_timer_init(&cli->timer, tip_client_timer_cb, TIP_CLIENT_TIMEOUT, 0.);
+	ev_timer_start(tip_main_loop, &cli->timer);
+}
+
+void tip_client_pending(struct tip_client *cli)
+{
+	ev_io_stop(tip_main_loop, &cli->io);
+	ev_timer_stop(tip_main_loop, &cli->timer);
+	cli->state = TIP_CLIENT_PENDING;
+}
+
+static void tip_client_activate_pending(void)
+{
+	struct tip_client *cli, *next;
+
+	list_for_each_entry_safe(cli, next, &client_list, list) {
+		if (cli->state != TIP_CLIENT_PENDING)
+			continue;
+
+		tip_client_redirect(cli);
+
+		ev_io_set(&cli->io, tip_client_socket(cli), EV_READ | EV_WRITE);
+		ev_io_start(tip_main_loop, &cli->io);
+		ev_timer_start(tip_main_loop, &cli->timer);
+		cli->state = TIP_CLIENT_PROCESSING_REQUEST_2;
+		break;
+	}
+}
+
+bool tip_client_redirect(struct tip_client *cli)
+{
+	struct tip_client_redirect *redir, *next;
+	char addr[INET_ADDRSTRLEN + 1];
+
+	if (!redirect)
+		return false;
+
+	inet_ntop(AF_INET, &cli->addr.sin_addr, addr, INET_ADDRSTRLEN);
+
+	list_for_each_entry_safe(redir, next, &client_redirect_list, list) {
+		if (strcmp(redir->uri, cli->uri) ||
+		    redir->addr.sin_addr.s_addr == cli->addr.sin_addr.s_addr)
+			continue;
+
+		cli->redirect = true;
+		cli->redirect_addr = redir->addr;
+
+		syslog(LOG_INFO, "redirecting client %s:%hu to %s:%hu",
+		       addr, htons(cli->addr.sin_port),
+		       inet_ntoa(redir->addr.sin_addr), htons(redir->addr.sin_port));
+
+		free((void *)redir->uri);
+		ev_timer_stop(tip_main_loop, &redir->timer);
+		list_del(&redir->list);
+		free(redir);
+
+		return true;
+	}
+	syslog(LOG_INFO, "no client redirections are available for %s:%hu",
+	       addr, htons(cli->addr.sin_port));
+
+	return false;
+}
+
+#define TIP_TCP_KEEPALIVE_IDLE	60
+#define TIP_TCP_KEEPALIVE_INTL	30
+#define TIP_TCP_KEEPALIVE_CNT	4
+
+void tip_server_accept_cb(struct ev_loop *loop, struct ev_io *io, int events)
+{
+	int intl = TIP_TCP_KEEPALIVE_INTL, cnt = TIP_TCP_KEEPALIVE_CNT;
+	int on = 1, idle = TIP_TCP_KEEPALIVE_IDLE;
+	struct sockaddr_in client_addr;
+	socklen_t addrlen = sizeof(client_addr);
+	struct tip_client *cli;
+	int client_sd, flags;
+
+	if (events & EV_ERROR)
+		return;
+
+	client_sd = accept(io->fd, (struct sockaddr *)&client_addr, &addrlen);
+	if (client_sd < 0) {
+		syslog(LOG_ERR, "cannot accept client connection\n");
+		return;
+	}
+
+	flags = fcntl(client_sd, F_GETFL);
+	fcntl(client_sd, F_SETFL, flags | O_NONBLOCK);
+
+	setsockopt(client_sd, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(int));
+	setsockopt(client_sd, IPPROTO_TCP, TCP_KEEPIDLE, &idle, sizeof(int));
+	setsockopt(client_sd, IPPROTO_TCP, TCP_KEEPINTVL, &intl, sizeof(int));
+	setsockopt(client_sd, IPPROTO_TCP, TCP_KEEPCNT, &cnt, sizeof(int));
+
+	cli = (struct tip_client *)calloc(1, sizeof(struct tip_client));
+	if (!cli) {
+		close(client_sd);
+		return;
+	}
+	memcpy(&cli->addr, &client_addr, sizeof(client_addr));
+	cli->fd = -1;
+
+	syslog(LOG_ERR, "accepting client connection from %s:%hu",
+	       inet_ntoa(cli->addr.sin_addr), htons(cli->addr.sin_port));
+
+	list_add_tail(&cli->list, &client_list);
+	ev_io_init(&cli->io, tip_client_cb, client_sd, EV_READ);
+
+	tip_client_start(cli);
+}
+
+int tip_socket_server_init(const char *port)
+{
+	struct sockaddr_in local;
+	int sd, on = 1;
+
+	sd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+	if (sd < 0) {
+		syslog(LOG_ERR, "cannot create main socket\n");
+		return -1;
+	}
+	setsockopt(sd, SOL_SOCKET, SO_REUSEPORT, &on, sizeof(int));
+
+	local.sin_addr.s_addr = htonl(INADDR_ANY);
+	local.sin_family = AF_INET;
+	local.sin_port = htons(atoi(port));
+
+	if (bind(sd, (struct sockaddr *) &local, sizeof(local)) < 0) {
+		close(sd);
+		syslog(LOG_ERR, "cannot bind socket\n");
+		return -1;
+	}
+
+	listen(sd, 250);
+
+	return sd;
+}
diff --git a/src/core.h b/src/core.h
new file mode 100644
index 0000000..524dd62
--- /dev/null
+++ b/src/core.h
@@ -0,0 +1,83 @@
+#ifndef _TIP_CORE_H
+#define _TIP_CORE_H
+
+#include <ev.h>
+#include "list.h"
+#include <stdbool.h>
+#include <netinet/in.h>
+
+#define TIP_MSG_REQUEST_MAXLEN	 131072
+
+extern const char *root;
+#define DEFAULT_MAX_CLIENTS 3
+extern int max_clients;
+extern int num_clients;
+extern bool redirect;
+/* max_client logic only applies for files larger than 1024 bytes. */
+#define FILE_SIZE_THRESHOLD 1024
+
+enum tip_client_state {
+	TIP_CLIENT_PENDING		= 0,
+	TIP_CLIENT_RECEIVING_HEADER,
+	TIP_CLIENT_RECEIVING_PAYLOAD,
+	TIP_CLIENT_PROCESSING_REQUEST,
+	TIP_CLIENT_PROCESSING_REQUEST_2,
+	TIP_CLIENT_PROCESSING_REQUEST_3,
+};
+
+struct tip_client {
+	struct list_head	list;
+	struct ev_io		io;
+	struct ev_timer		timer;
+	struct sockaddr_in	addr;
+	enum tip_client_state	state;
+	char			buf[TIP_MSG_REQUEST_MAXLEN];
+	unsigned int		buf_len;
+	unsigned int		msg_len;
+	int			content_length;
+	char			auth_token[64];
+
+	/* for file serving. */
+	const char		*uri;
+	const char		*path;
+	size_t			size;
+	int			fd;
+	off_t			offset;
+
+	/* for redirection. */
+	bool			redirect;
+	struct sockaddr_in	redirect_addr;
+	bool			allow_redirect;
+};
+
+static inline int tip_client_socket(const struct tip_client *cli)
+{
+	return cli->io.fd;
+}
+
+void tip_client_pending(struct tip_client *cli);
+bool tip_client_redirect(struct tip_client *cli);
+
+extern struct ev_loop *tip_main_loop;
+
+int tip_socket_server_init(const char *port);
+void tip_server_accept_cb(struct ev_loop *loop, struct ev_io *io, int events);
+
+int tip_client_state_process_payload(struct tip_client *cli);
+int tip_client_state_process_payload_reply(struct tip_client *cli);
+int tip_client_state_process_payload_bulk(struct tip_client *cli);
+
+enum tip_http_method {
+	TIP_METHOD_GET	= 0,
+	TIP_METHOD_POST,
+	TIP_METHOD_NO_HTTP
+};
+
+struct tip_client_redirect {
+	struct list_head	list;
+	struct sockaddr_in	addr;
+	const char		*uri;
+	struct ev_timer		timer;
+};
+
+#endif
diff --git a/src/handler.c b/src/handler.c
new file mode 100644
index 0000000..9bcec71
--- /dev/null
+++ b/src/handler.c
@@ -0,0 +1,155 @@
+#include "core.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <syslog.h>
+#include <sys/ioctl.h>
+#include <netinet/in.h>
+#include <ifaddrs.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <netinet/tcp.h>
+#include <fcntl.h>
+#include <time.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <sys/sendfile.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <limits.h>
+#include <errno.h>
+
+static int tip_client_method_not_found(struct tip_client *cli)
+{
+	/* To meet RFC 7231, this function MUST generate an Allow header field
+	 * containing the correct methods. For example: "Allow: POST\r\n"
+	 */
+	char buf[] = "HTTP/1.1 405 Method Not Allowed\r\n"
+		     "Content-Length: 0\r\n\r\n";
+
+	send(tip_client_socket(cli), buf, strlen(buf), 0);
+
+	return -1;
+}
+
+static int tip_client_file_not_found(struct tip_client *cli)
+{
+	char buf[] = "HTTP/1.1 404 Not Found\r\n"
+		     "Content-Length: 0\r\n\r\n";
+
+	send(tip_client_socket(cli), buf, strlen(buf), 0);
+
+	return -1;
+}
+
+/* TODO: sanitize uri, don't escape directory serving files. */
+static bool sanitize(const char *uri)
+{
+	return true;
+}
+
+#define BLOCK 1024000
+
+int tip_client_state_process_payload(struct tip_client *cli)
+{
+	const char *trailer, *x_redirect;
+	enum tip_http_method method;
+	bool allow_redirect = true;
+	char _uri[32], *uri = _uri;
+	char path[PATH_MAX + 1];
+	char redirect[5];
+	struct stat st;
+	int err;
+
+/*	syslog(LOG_DEBUG, "%s:rhu %.32s ...\n",
+	       inet_ntoa(cli->addr.sin_addr),
+	       ntohs(cli->addr.sin_port), cli->buf); */
+
+	if (!strncmp(cli->buf, "GET", strlen("GET"))) {
+		method = TIP_METHOD_GET;
+		if (sscanf(cli->buf, "GET %31s HTTP/1.1", uri) != 1)
+			return tip_client_method_not_found(cli);
+	} else {
+		return tip_client_method_not_found(cli);
+	}
+
+	x_redirect = strstr(cli->buf, "X-Accept-Redirect: ");
+	if (x_redirect &&
+	    sscanf(x_redirect, "X-Accept-Redirect: %4s", redirect) == 1 &&
+	    !strncmp(redirect, "off", strlen("off")))
+		allow_redirect = false;
+
+	trailer = strstr(cli->buf, "\r\n\r\n");
+
+	if (!sanitize(uri))
+		return tip_client_method_not_found(cli);
+
+	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++;
+
+	cli->uri = strdup(uri);
+	cli->path = strdup(path);
+	cli->size = st.st_size;
+	cli->allow_redirect = allow_redirect;
+
+	num_clients++;
+	if (cli->size > FILE_SIZE_THRESHOLD && num_clients > max_clients) {
+		if (!tip_client_redirect(cli)) {
+			tip_client_pending(cli);
+			return 1;
+		}
+	}
+
+	cli->state = TIP_CLIENT_PROCESSING_REQUEST_2;
+
+	return 0;
+}
+
+int tip_client_state_process_payload_reply(struct tip_client *cli)
+{
+	char buf[1024];
+	int fd;
+
+	if (cli->redirect) {
+		snprintf(buf, sizeof(buf),
+			 "HTTP/1.1 301 Moves Permanently\r\nLocation: http://%s:%hu/%s\r\n\r\n",
+			 inet_ntoa(cli->redirect_addr.sin_addr),
+			 htons(cli->redirect_addr.sin_port), cli->uri);
+		send(tip_client_socket(cli), buf, strlen(buf), 0);
+
+		return 1;
+	}
+
+	fd = open(cli->path, O_RDONLY);
+	if (fd < 0)
+		return tip_client_file_not_found(cli);
+
+	snprintf(buf, sizeof(buf),
+		 "HTTP/1.1 200 OK\r\nContent-Length: %lu\r\n\r\n",
+		 cli->size);
+
+	send(tip_client_socket(cli), buf, strlen(buf), 0);
+
+	cli->fd = fd;
+	cli->state = TIP_CLIENT_PROCESSING_REQUEST_3;
+
+	return 0;
+}
+
+int tip_client_state_process_payload_bulk(struct tip_client *cli)
+{
+	sendfile(tip_client_socket(cli), cli->fd, &cli->offset, BLOCK);
+
+	if (cli->offset >= cli->size)
+		return 1;
+
+	return 0;
+}
diff --git a/src/list.h b/src/list.h
new file mode 100644
index 0000000..8dfd476
--- /dev/null
+++ b/src/list.h
@@ -0,0 +1,162 @@
+#ifndef _LINUX_LIST_H
+#define _LINUX_LIST_H
+
+#include <stddef.h>
+
+#define container_of(ptr, type, member) ({			\
+	typeof( ((type *)0)->member ) *__mptr = (ptr);		\
+	(type *)( (char *)__mptr - offsetof(type,member) );})
+
+/*
+ * These are non-NULL pointers that will result in page faults
+ * under normal circumstances, used to verify that nobody uses
+ * non-initialized list entries.
+ */
+#define LIST_POISON1  ((void *) 0x00100100)
+#define LIST_POISON2  ((void *) 0x00200200)
+
+/*
+ * Simple doubly linked list implementation.
+ *
+ * Some of the internal functions ("__xxx") are useful when
+ * manipulating whole lists rather than single entries, as
+ * sometimes we already know the next/prev entries and we can
+ * generate better code by using them directly rather than
+ * using the generic single-entry routines.
+ */
+
+struct list_head {
+	struct list_head *next, *prev;
+};
+
+#define LIST_HEAD_INIT(name) { &(name), &(name) }
+
+#define LIST_HEAD(name) \
+	struct list_head name = LIST_HEAD_INIT(name)
+
+#define INIT_LIST_HEAD(ptr) do { \
+	(ptr)->next = (ptr); (ptr)->prev = (ptr); \
+} while (0)
+
+/*
+ * Insert a new entry between two known consecutive entries.
+ *
+ * This is only for internal list manipulation where we know
+ * the prev/next entries already!
+ */
+static inline void __list_add(struct list_head *new,
+			      struct list_head *prev,
+			      struct list_head *next)
+{
+	next->prev = new;
+	new->next = next;
+	new->prev = prev;
+	prev->next = new;
+}
+
+/**
+ * list_add - add a new entry
+ * @new: new entry to be added
+ * @head: list head to add it after
+ *
+ * Insert a new entry after the specified head.
+ * This is good for implementing stacks.
+ */
+static inline void list_add(struct list_head *new, struct list_head *head)
+{
+	__list_add(new, head, head->next);
+}
+
+/**
+ * list_add_tail - add a new entry
+ * @new: new entry to be added
+ * @head: list head to add it before
+ *
+ * Insert a new entry before the specified head.
+ * This is useful for implementing queues.
+ */
+static inline void list_add_tail(struct list_head *new, struct list_head *head)
+{
+	__list_add(new, head->prev, head);
+}
+
+/*
+ * Delete a list entry by making the prev/next entries
+ * point to each other.
+ *
+ * This is only for internal list manipulation where we know
+ * the prev/next entries already!
+ */
+static inline void __list_del(struct list_head * prev, struct list_head * next)
+{
+	next->prev = prev;
+	prev->next = next;
+}
+
+/**
+ * list_del - deletes entry from list.
+ * @entry: the element to delete from the list.
+ * Note: list_empty on entry does not return true after this, the entry is
+ * in an undefined state.
+ */
+static inline void list_del(struct list_head *entry)
+{
+	__list_del(entry->prev, entry->next);
+	entry->next = LIST_POISON1;
+	entry->prev = LIST_POISON2;
+}
+
+/**
+ * list_empty - tests whether a list is empty
+ * @head: the list to test.
+ */
+static inline int list_empty(const struct list_head *head)
+{
+	return head->next == head;
+}
+
+/**
+ * list_entry - get the struct for this entry
+ * @ptr:	the &struct list_head pointer.
+ * @type:	the type of the struct this is embedded in.
+ * @member:	the name of the list_struct within the struct.
+ */
+#define list_entry(ptr, type, member) \
+	container_of(ptr, type, member)
+
+/**
+ * list_first_entry - get the first element from a list
+ * @ptr:	the list head to take the element from.
+ * @type:	the type of the struct this is embedded in.
+ * @member:	the name of the list_head within the struct.
+ *
+ * Note, that list is expected to be not empty.
+ */
+#define list_first_entry(ptr, type, member) \
+	list_entry((ptr)->next, type, member)
+
+/**
+ * list_for_each_entry	-	iterate over list of given type
+ * @pos:	the type * to use as a loop counter.
+ * @head:	the head for your list.
+ * @member:	the name of the list_struct within the struct.
+ */
+#define list_for_each_entry(pos, head, member)				\
+	for (pos = list_entry((head)->next, typeof(*pos), member);	\
+	     &pos->member != (head); 					\
+	     pos = list_entry(pos->member.next, typeof(*pos), member))
+
+/**
+ * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
+ * @pos:	the type * to use as a loop counter.
+ * @n:		another type * to use as temporary storage
+ * @head:	the head for your list.
+ * @member:	the name of the list_struct within the struct.
+ */
+#define list_for_each_entry_safe(pos, n, head, member)			\
+	for (pos = list_entry((head)->next, typeof(*pos), member),	\
+		n = list_entry(pos->member.next, typeof(*pos), member);	\
+	     &pos->member != (head); 					\
+	     pos = n, n = list_entry(n->member.next, typeof(*n), member))
+
+#endif
diff --git a/src/main.c b/src/main.c
new file mode 100644
index 0000000..fd543a2
--- /dev/null
+++ b/src/main.c
@@ -0,0 +1,95 @@
+/*
+ * Copyright (C) 2020-2021 Soleta Networks <info@soleta.eu>
+ *
+ * This program is free software: you can redistribute it and/or modify it under
+ * the terms of the GNU Affero General Public License as published by the
+ * Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ */
+
+#include "core.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <syslog.h>
+#include <sys/ioctl.h>
+#include <netinet/in.h>
+#include <ifaddrs.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <netinet/tcp.h>
+#include <fcntl.h>
+#include <time.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <errno.h>
+#include <getopt.h>
+
+int max_clients = DEFAULT_MAX_CLIENTS;
+const char *root = ".";
+bool redirect;
+
+static struct option tip_repo_opts[] = {
+	{ "max-clients", 1, 0, 'n' },
+	{ "redirect", 0, 0, 'r' },
+	{ "root", 1, 0, 't' },
+	{ NULL },
+};
+
+struct ev_io ev_io_server_rest;
+
+int main(int argc, char *argv[])
+{
+	int socket_rest, val;
+
+	openlog("tiptorrent", LOG_PID, LOG_DAEMON);
+
+	tip_main_loop = ev_default_loop(0);
+
+	if (signal(SIGPIPE, SIG_IGN) == SIG_ERR)
+		exit(EXIT_FAILURE);
+
+	while (1) {
+		val = getopt_long(argc, argv, "n:r", tip_repo_opts, NULL);
+		if (val < 0)
+			break;
+
+		switch (val) {
+			case 'n':
+				max_clients = atoi(optarg);
+				if (max_clients <= 0) {
+					syslog(LOG_ERR, "Invalid number for max_clients");
+					return EXIT_FAILURE;
+				}
+				break;
+			case 'r':
+				redirect = true;
+				break;
+			case 't':
+				root = strdup(optarg);
+				break;
+			case '?':
+				return EXIT_FAILURE;
+			default:
+				break;
+		}
+	}
+
+	socket_rest = tip_socket_server_init("9999");
+	if (socket_rest < 0) {
+		syslog(LOG_ERR, "Cannot open tiptorrent server socket\n");
+		exit(EXIT_FAILURE);
+	}
+
+	ev_io_init(&ev_io_server_rest, tip_server_accept_cb, socket_rest, EV_READ);
+	ev_io_start(tip_main_loop, &ev_io_server_rest);
+
+	syslog(LOG_INFO, "Waiting for connections\n");
+
+	while (1)
+		ev_loop(tip_main_loop, 0);
+
+	exit(EXIT_SUCCESS);
+}
diff --git a/tests/network-setup.sh b/tests/network-setup.sh
new file mode 100755
index 0000000..c8f16db
--- /dev/null
+++ b/tests/network-setup.sh
@@ -0,0 +1,84 @@
+#!/bin/bash
+
+if [ $UID -ne 0 ]
+then
+	echo "You must be root to run this test script"
+	exit 0
+fi
+
+#                               / c1
+#                              /- c2
+#               srv ----- br -- c3
+#                              \- c4
+
+start () {
+	ip netns add srv
+	ip netns add br
+	ip netns add c1
+	ip netns add c2
+	ip netns add c3
+	ip netns add c4
+
+	ip link add veth0 netns srv type veth peer name veth0 netns br
+	ip link add veth1 netns br type veth peer name veth0 netns c1
+	ip link add veth2 netns br type veth peer name veth0 netns c2
+	ip link add veth3 netns br type veth peer name veth0 netns c3
+	ip link add veth4 netns br type veth peer name veth0 netns c4
+
+	ip -net br link set up dev veth0
+	ip -net br link set up dev veth1
+	ip -net br link set up dev veth2
+	ip -net br link set up dev veth3
+	ip -net br link set up dev veth4
+	ip -net br link add name br0 type bridge
+	ip -net br link set dev veth0 master br0
+	ip -net br link set dev veth1 master br0
+	ip -net br link set dev veth2 master br0
+	ip -net br link set dev veth3 master br0
+	ip -net br link set dev veth4 master br0
+	ip -net br link set up dev br0
+
+	ip -net srv addr add 10.141.10.1/24 dev veth0
+	ip -net srv link set up dev veth0
+	ip netns exec srv .././grepo --max-clients 1 --redirect --root . &
+
+	ip -net c1 addr add 10.141.10.2/24 dev veth0
+	ip -net c1 link set up dev veth0
+	ip netns exec c1 .././tiptorrent --max-clients 1 &
+
+	ip -net c2 addr add 10.141.10.3/24 dev veth0
+	ip -net c2 link set up dev veth0
+	ip netns exec c2 .././tiptorrent --max-clients 1 &
+
+	ip -net c3 addr add 10.141.10.4/24 dev veth0
+	ip -net c3 link set up dev veth0
+	ip netns exec c3 .././tiptorrent --max-clients 1 &
+
+	ip -net c4 addr add 10.141.10.5/24 dev veth0
+	ip -net c4 link set up dev veth0
+	ip netns exec c4 .././tiptorrent --max-clients 1 &
+}
+
+stop () {
+	ip netns del srv
+	ip netns del br
+	ip netns del c1
+	ip netns del c2
+	ip netns del c3
+	ip netns del c4
+	killall -15 tiptorrent
+}
+
+case $1 in
+start)
+	start
+	;;
+stop)
+	stop
+	;;
+*)
+	echo "$0 [start|stop]"
+	;;
+esac
+
+exit 0
diff --git a/tests/run-clients.sh b/tests/run-clients.sh
new file mode 100755
index 0000000..3857494
--- /dev/null
+++ b/tests/run-clients.sh
@@ -0,0 +1,18 @@
+#!/bin/bash
+
+if [ ! -f TEST ]
+then
+	echo "create the TEST first, e.g. dd if=/dev/urandom of=TEST bs=750M count=1 iflag=fullblock"
+	exit 0
+fi
+
+if [ $UID -ne 0 ]
+then
+	echo "You must be root to run this test script"
+	exit 0
+fi
+
+ip netns exec c1 wget http://10.141.10.1:9999/TEST -O /dev/null &
+ip netns exec c2 wget http://10.141.10.1:9999/TEST -O /dev/null &
+ip netns exec c3 wget http://10.141.10.1:9999/TEST -O /dev/null &
+ip netns exec c4 wget http://10.141.10.1:9999/TEST -O /dev/null &