nmap/nsock/src/proxy_http.c

/***************************************************************************
 * proxy_http.c -- HTTP Connect proxying.                                  *
 *                                                                         *
 ***********************IMPORTANT NSOCK LICENSE TERMS***********************
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 *                                                                         *
 ***************************************************************************/

/* $Id $ */

#define _GNU_SOURCE
#include <stdio.h>

#include "nsock.h"
#include "nsock_internal.h"
#include <netdb.h>
#include <string.h>

#define DEFAULT_PROXY_PORT_HTTP 8080


extern struct timeval nsock_tod;

/* ---- PROTOTYPES ---- */
static int proxy_http_node_new(struct proxy_node **node, const struct uri *uri);
static void proxy_http_node_delete(struct proxy_node *node);
static void proxy_http_handler(nsock_pool nspool, nsock_event nsevent, void *udata);


/* ---- PROXY DEFINITION ---- */
const struct proxy_op proxy_http_ops = {
  .prefix      = "http://",
  .type        = PROXY_TYPE_HTTP,
  .node_new    = proxy_http_node_new,
  .node_delete = proxy_http_node_delete,
  .handler     = proxy_http_handler,
};


int proxy_http_node_new(struct proxy_node **node, const struct uri *uri) {
  int rc;
  struct proxy_node *proxy;

  proxy = (struct proxy_node *)safe_zalloc(sizeof(struct proxy_node));
  proxy->ops = &proxy_http_ops;

  rc = proxy_resolve(uri->host, (struct sockaddr *)&proxy->ss, &proxy->sslen);
  if (rc < 0) {
    free(proxy);
    *node = NULL;
    return -1;
  }

  if (uri->port == -1)
    proxy->port = DEFAULT_PROXY_PORT_HTTP;
  else
    proxy->port = (unsigned short)uri->port;

  rc = asprintf(&proxy->nodestr, "http://%s:%d", uri->host, proxy->port);
  if (rc < 0) {
    /* asprintf() failed for some reason but this is not a disaster (yet).
     * Set nodestr to NULL and try to keep on going. */
    proxy->nodestr = NULL;
  }

  *node = proxy;

  return 1;
}

void proxy_http_node_delete(struct proxy_node *node) {
  if (!node)
    return;

  if (node->nodestr)
    free(node->nodestr);

  free(node);
}

void proxy_http_handler(nsock_pool nspool, nsock_event nsevent, void *udata) {
  mspool *nsp = (mspool *)nspool;
  msevent *nse = (msevent *)nsevent;
  struct sockaddr_storage *ss;
  size_t sslen;
  unsigned short port;
  struct proxy_node *next;
  int timeout;

  switch (nse->iod->px_ctx->px_state) {
    case PROXY_STATE_INITIAL:
      nse->iod->px_ctx->px_state = PROXY_STATE_HTTP_TCP_CONNECTED;

      next = proxy_ctx_node_next(nse->iod->px_ctx);
      if (next) {
        ss = &next->ss;
        sslen = next->sslen;
        port = next->port;
      } else {
        ss = &nse->iod->px_ctx->target_ss;
        sslen = nse->iod->px_ctx->target_sslen;
        port = nse->iod->px_ctx->target_port;
      }

      timeout = TIMEVAL_MSEC_SUBTRACT(nse->timeout, nsock_tod);
      nsock_printf(nspool, (nsock_iod)nse->iod, nsock_proxy_ev_dispatch,
                   timeout, udata, "CONNECT %s:%d HTTP/1.1\r\n\r\n",
                   inet_ntop_ez(ss, sslen), (int)port);

      nsock_readlines(nspool, (nsock_iod)nse->iod, nsock_proxy_ev_dispatch,
                      timeout, udata, 1);
      break;

    case PROXY_STATE_HTTP_TCP_CONNECTED:
      if (nse->type == NSE_TYPE_READ) {
        char *res;
        int reslen;

        res = nse_readbuf(nse, &reslen);

        /* TODO string check!! */
        if ((reslen >= 15) && strstr(res, "200 OK")) {
          nse->iod->px_ctx->px_state = PROXY_STATE_HTTP_TUNNEL_ESTABLISHED;
        }

        if (nse->iod->px_ctx->px_current->next == NULL) {
          forward_event(nsp, nse, udata);
        } else {
          nse->iod->px_ctx->px_current = nse->iod->px_ctx->px_current->next;
          nse->iod->px_ctx->px_state = PROXY_STATE_INITIAL;
          nsock_proxy_ev_dispatch(nsp, nse, udata);
        }
      }
      break;

    case PROXY_STATE_HTTP_TUNNEL_ESTABLISHED:
      forward_event(nsp, nse, udata);
      break;

    default:
      fatal("Invalid proxy state!");
  }
}