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-rw-r--r--sample/le-proxy.c291
1 files changed, 291 insertions, 0 deletions
diff --git a/sample/le-proxy.c b/sample/le-proxy.c
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index 000000000000..8d9b529ee68d
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+++ b/sample/le-proxy.c
@@ -0,0 +1,291 @@
+/*
+ This example code shows how to write an (optionally encrypting) SSL proxy
+ with Libevent's bufferevent layer.
+
+ XXX It's a little ugly and should probably be cleaned up.
+ */
+
+// Get rid of OSX 10.7 and greater deprecation warnings.
+#if defined(__APPLE__) && defined(__clang__)
+#pragma clang diagnostic ignored "-Wdeprecated-declarations"
+#endif
+
+#include <stdio.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+#ifdef _WIN32
+#include <winsock2.h>
+#include <ws2tcpip.h>
+#else
+#include <sys/socket.h>
+#include <netinet/in.h>
+#endif
+
+#include <event2/bufferevent_ssl.h>
+#include <event2/bufferevent.h>
+#include <event2/buffer.h>
+#include <event2/listener.h>
+#include <event2/util.h>
+
+#include <openssl/ssl.h>
+#include <openssl/err.h>
+#include <openssl/rand.h>
+#include "openssl-compat.h"
+
+static struct event_base *base;
+static struct sockaddr_storage listen_on_addr;
+static struct sockaddr_storage connect_to_addr;
+static int connect_to_addrlen;
+static int use_wrapper = 1;
+
+static SSL_CTX *ssl_ctx = NULL;
+
+#define MAX_OUTPUT (512*1024)
+
+static void drained_writecb(struct bufferevent *bev, void *ctx);
+static void eventcb(struct bufferevent *bev, short what, void *ctx);
+
+static void
+readcb(struct bufferevent *bev, void *ctx)
+{
+ struct bufferevent *partner = ctx;
+ struct evbuffer *src, *dst;
+ size_t len;
+ src = bufferevent_get_input(bev);
+ len = evbuffer_get_length(src);
+ if (!partner) {
+ evbuffer_drain(src, len);
+ return;
+ }
+ dst = bufferevent_get_output(partner);
+ evbuffer_add_buffer(dst, src);
+
+ if (evbuffer_get_length(dst) >= MAX_OUTPUT) {
+ /* We're giving the other side data faster than it can
+ * pass it on. Stop reading here until we have drained the
+ * other side to MAX_OUTPUT/2 bytes. */
+ bufferevent_setcb(partner, readcb, drained_writecb,
+ eventcb, bev);
+ bufferevent_setwatermark(partner, EV_WRITE, MAX_OUTPUT/2,
+ MAX_OUTPUT);
+ bufferevent_disable(bev, EV_READ);
+ }
+}
+
+static void
+drained_writecb(struct bufferevent *bev, void *ctx)
+{
+ struct bufferevent *partner = ctx;
+
+ /* We were choking the other side until we drained our outbuf a bit.
+ * Now it seems drained. */
+ bufferevent_setcb(bev, readcb, NULL, eventcb, partner);
+ bufferevent_setwatermark(bev, EV_WRITE, 0, 0);
+ if (partner)
+ bufferevent_enable(partner, EV_READ);
+}
+
+static void
+close_on_finished_writecb(struct bufferevent *bev, void *ctx)
+{
+ struct evbuffer *b = bufferevent_get_output(bev);
+
+ if (evbuffer_get_length(b) == 0) {
+ bufferevent_free(bev);
+ }
+}
+
+static void
+eventcb(struct bufferevent *bev, short what, void *ctx)
+{
+ struct bufferevent *partner = ctx;
+
+ if (what & (BEV_EVENT_EOF|BEV_EVENT_ERROR)) {
+ if (what & BEV_EVENT_ERROR) {
+ unsigned long err;
+ while ((err = (bufferevent_get_openssl_error(bev)))) {
+ const char *msg = (const char*)
+ ERR_reason_error_string(err);
+ const char *lib = (const char*)
+ ERR_lib_error_string(err);
+ const char *func = (const char*)
+ ERR_func_error_string(err);
+ fprintf(stderr,
+ "%s in %s %s\n", msg, lib, func);
+ }
+ if (errno)
+ perror("connection error");
+ }
+
+ if (partner) {
+ /* Flush all pending data */
+ readcb(bev, ctx);
+
+ if (evbuffer_get_length(
+ bufferevent_get_output(partner))) {
+ /* We still have to flush data from the other
+ * side, but when that's done, close the other
+ * side. */
+ bufferevent_setcb(partner,
+ NULL, close_on_finished_writecb,
+ eventcb, NULL);
+ bufferevent_disable(partner, EV_READ);
+ } else {
+ /* We have nothing left to say to the other
+ * side; close it. */
+ bufferevent_free(partner);
+ }
+ }
+ bufferevent_free(bev);
+ }
+}
+
+static void
+syntax(void)
+{
+ fputs("Syntax:\n", stderr);
+ fputs(" le-proxy [-s] [-W] <listen-on-addr> <connect-to-addr>\n", stderr);
+ fputs("Example:\n", stderr);
+ fputs(" le-proxy 127.0.0.1:8888 1.2.3.4:80\n", stderr);
+
+ exit(1);
+}
+
+static void
+accept_cb(struct evconnlistener *listener, evutil_socket_t fd,
+ struct sockaddr *a, int slen, void *p)
+{
+ struct bufferevent *b_out, *b_in;
+ /* Create two linked bufferevent objects: one to connect, one for the
+ * new connection */
+ b_in = bufferevent_socket_new(base, fd,
+ BEV_OPT_CLOSE_ON_FREE|BEV_OPT_DEFER_CALLBACKS);
+
+ if (!ssl_ctx || use_wrapper)
+ b_out = bufferevent_socket_new(base, -1,
+ BEV_OPT_CLOSE_ON_FREE|BEV_OPT_DEFER_CALLBACKS);
+ else {
+ SSL *ssl = SSL_new(ssl_ctx);
+ b_out = bufferevent_openssl_socket_new(base, -1, ssl,
+ BUFFEREVENT_SSL_CONNECTING,
+ BEV_OPT_CLOSE_ON_FREE|BEV_OPT_DEFER_CALLBACKS);
+ }
+
+ assert(b_in && b_out);
+
+ if (bufferevent_socket_connect(b_out,
+ (struct sockaddr*)&connect_to_addr, connect_to_addrlen)<0) {
+ perror("bufferevent_socket_connect");
+ bufferevent_free(b_out);
+ bufferevent_free(b_in);
+ return;
+ }
+
+ if (ssl_ctx && use_wrapper) {
+ struct bufferevent *b_ssl;
+ SSL *ssl = SSL_new(ssl_ctx);
+ b_ssl = bufferevent_openssl_filter_new(base,
+ b_out, ssl, BUFFEREVENT_SSL_CONNECTING,
+ BEV_OPT_CLOSE_ON_FREE|BEV_OPT_DEFER_CALLBACKS);
+ if (!b_ssl) {
+ perror("Bufferevent_openssl_new");
+ bufferevent_free(b_out);
+ bufferevent_free(b_in);
+ }
+ b_out = b_ssl;
+ }
+
+ bufferevent_setcb(b_in, readcb, NULL, eventcb, b_out);
+ bufferevent_setcb(b_out, readcb, NULL, eventcb, b_in);
+
+ bufferevent_enable(b_in, EV_READ|EV_WRITE);
+ bufferevent_enable(b_out, EV_READ|EV_WRITE);
+}
+
+int
+main(int argc, char **argv)
+{
+ int i;
+ int socklen;
+
+ int use_ssl = 0;
+ struct evconnlistener *listener;
+
+ if (argc < 3)
+ syntax();
+
+ for (i=1; i < argc; ++i) {
+ if (!strcmp(argv[i], "-s")) {
+ use_ssl = 1;
+ } else if (!strcmp(argv[i], "-W")) {
+ use_wrapper = 0;
+ } else if (argv[i][0] == '-') {
+ syntax();
+ } else
+ break;
+ }
+
+ if (i+2 != argc)
+ syntax();
+
+ memset(&listen_on_addr, 0, sizeof(listen_on_addr));
+ socklen = sizeof(listen_on_addr);
+ if (evutil_parse_sockaddr_port(argv[i],
+ (struct sockaddr*)&listen_on_addr, &socklen)<0) {
+ int p = atoi(argv[i]);
+ struct sockaddr_in *sin = (struct sockaddr_in*)&listen_on_addr;
+ if (p < 1 || p > 65535)
+ syntax();
+ sin->sin_port = htons(p);
+ sin->sin_addr.s_addr = htonl(0x7f000001);
+ sin->sin_family = AF_INET;
+ socklen = sizeof(struct sockaddr_in);
+ }
+
+ memset(&connect_to_addr, 0, sizeof(connect_to_addr));
+ connect_to_addrlen = sizeof(connect_to_addr);
+ if (evutil_parse_sockaddr_port(argv[i+1],
+ (struct sockaddr*)&connect_to_addr, &connect_to_addrlen)<0)
+ syntax();
+
+ base = event_base_new();
+ if (!base) {
+ perror("event_base_new()");
+ return 1;
+ }
+
+ if (use_ssl) {
+ int r;
+#if OPENSSL_VERSION_NUMBER < 0x10100000L
+ SSL_library_init();
+ ERR_load_crypto_strings();
+ SSL_load_error_strings();
+ OpenSSL_add_all_algorithms();
+#endif
+ r = RAND_poll();
+ if (r == 0) {
+ fprintf(stderr, "RAND_poll() failed.\n");
+ return 1;
+ }
+ ssl_ctx = SSL_CTX_new(TLS_method());
+ }
+
+ listener = evconnlistener_new_bind(base, accept_cb, NULL,
+ LEV_OPT_CLOSE_ON_FREE|LEV_OPT_CLOSE_ON_EXEC|LEV_OPT_REUSEABLE,
+ -1, (struct sockaddr*)&listen_on_addr, socklen);
+
+ if (! listener) {
+ fprintf(stderr, "Couldn't open listener.\n");
+ event_base_free(base);
+ return 1;
+ }
+ event_base_dispatch(base);
+
+ evconnlistener_free(listener);
+ event_base_free(base);
+
+ return 0;
+}
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