tiptorrent/src/handler.c

#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;
}

static bool sanitize(const char *uri)
{
	/* TODO: smarter sanitization. */
	if (strstr(uri, ".."))
		return false;

	return true;
}

#define BLOCK 1024000

int tip_client_state_process_payload(struct tip_client *cli)
{
	const char *trailer, *x_redirect;
	bool allow_redirect = true;
	char _uri[32], *uri = _uri;
	char allow_redirect_str[5];
	char path[PATH_MAX + 1];
	char *chunk = NULL;
	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"))) {
		cli->method = TIP_METHOD_GET;
		if (sscanf(cli->buf, "GET %31s HTTP/1.1", uri) != 1)
			return tip_client_method_not_found(cli);
	} else if (!strncmp(cli->buf, "HEAD", strlen("HEAD"))) {
		cli->method = TIP_METHOD_HEAD;
		if (sscanf(cli->buf, "HEAD %31s HTTP/1.1", uri) != 1)
			return tip_client_method_not_found(cli);
	} else if (!strncmp(cli->buf, "POST", strlen("POST"))) {
		cli->method = TIP_METHOD_POST;
		if (sscanf(cli->buf, "POST %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", allow_redirect_str) == 1 &&
	    !strncmp(allow_redirect_str, "off", strlen("off")))
		allow_redirect = false;

	trailer = strstr(cli->buf, "\r\n\r\n");

	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);

	/* restore the original uri that was mangled. */
	if (chunk) {
		chunk--;
		*chunk = '.';
	}

	cli->uri = strdup(uri);
	cli->path = strdup(path);
	cli->size = st.st_size;

	switch (cli->method) {
	case TIP_METHOD_GET:
		break;
	case TIP_METHOD_HEAD:
		cli->state = TIP_CLIENT_PROCESSING_REQUEST_2;
		return 0;
	case TIP_METHOD_POST:
		cli->allow_redirect = true;
		tip_client_redirect_create(cli);
		tip_client_activate_pending(true);
		cli->state = TIP_CLIENT_PROCESSING_REQUEST_2;
		return 0;
	}

	if (tip_client_large_file(cli)) {
		cli->allow_redirect = allow_redirect;

		num_clients++;
		if (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)
{
	uint64_t chunk_size;
	off_t chunk_offset;
	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);

	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",
		 cli->size);

	send(tip_client_socket(cli), buf, strlen(buf), 0);

	cli->fd = fd;
	switch (cli->method) {
	case TIP_METHOD_GET:
		cli->state = TIP_CLIENT_PROCESSING_REQUEST_3;
		break;
	case TIP_METHOD_HEAD:
	case TIP_METHOD_POST:
		/* close connection. */
		return 1;
	}

	return 0;
}

int tip_client_state_process_payload_bulk(struct tip_client *cli)
{
	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;

	cli->left -= ret;

	if (cli->left <= 0) {
		cli->state = TIP_CLIENT_CLOSE_WAIT;
		return 1;
	}

	return 0;
}