/*
 * Copyright (C) 2012 by Darren Reed.
 *
 * See the IPFILTER.LICENCE file for details on licencing.
 *
 * $Id: load_http.c,v 1.5.2.5 2012/07/22 08:04:24 darren_r Exp $
 */

#include "ipf.h"
#include <ctype.h>

/*
 * Because the URL can be included twice into the buffer, once as the
 * full path for the "GET" and once as the "Host:", the buffer it is
 * put in needs to be larger than 512*2 to make room for the supporting
 * text. Why not just use snprintf and truncate? The warning about the
 * URL being too long tells you something is wrong and does not fetch
 * any data - just truncating the URL (with snprintf, etc) and sending
 * that to the server is allowing an unknown and unintentioned action
 * to happen.
 */
#define MAX_URL_LEN     512
#define LOAD_BUFSIZE    (MAX_URL_LEN * 2 + 128)

/*
 * Format expected is one address per line, at the start of each line.
 */
alist_t *
load_http(char *url)
{
        int fd, len, left, port, endhdr, removed, linenum = 0;
        char *s, *t, *u, buffer[LOAD_BUFSIZE], *myurl;
        alist_t *a, *rtop, *rbot;
        size_t avail;
        int error;

        /*
         * More than this would just be absurd.
         */
        if (strlen(url) > MAX_URL_LEN) {
                fprintf(stderr, "load_http has a URL > %d bytes?!\n",
                        MAX_URL_LEN);
                return (NULL);
        }

        fd = -1;
        rtop = NULL;
        rbot = NULL;

        avail = sizeof(buffer);
        error = snprintf(buffer, avail, "GET %s HTTP/1.0\r\n", url);

        /*
         * error is always less then avail due to the constraint on
         * the url length above.
         */
        avail -= error;

        myurl = strdup(url);
        if (myurl == NULL)
                goto done;

        s = myurl + 7;                  /* http:// */
        t = strchr(s, '/');
        if (t == NULL) {
                fprintf(stderr, "load_http has a malformed URL '%s'\n", url);
                free(myurl);
                return (NULL);
        }
        *t++ = '\0';

        /*
         * 10 is the length of 'Host: \r\n\r\n' below.
         */
        if (strlen(s) + strlen(buffer) + 10 > sizeof(buffer)) {
                fprintf(stderr, "load_http has a malformed URL '%s'\n", url);
                free(myurl);
                return (NULL);
        }

        u = strchr(s, '@');
        if (u != NULL)
                s = u + 1;              /* AUTH */

        error = snprintf(buffer + strlen(buffer), avail, "Host: %s\r\n\r\n", s);
        if (error >= avail) {
                fprintf(stderr, "URL is too large: %s\n", url);
                goto done;
        }

        u = strchr(s, ':');
        if (u != NULL) {
                *u++ = '\0';
                port = atoi(u);
                if (port < 0 || port > 65535)
                        goto done;
        } else {
                port = 80;
        }


        fd = connecttcp(s, port);
        if (fd == -1)
                goto done;


        len = strlen(buffer);
        if (write(fd, buffer, len) != len)
                goto done;

        s = buffer;
        endhdr = 0;
        left = sizeof(buffer) - 1;

        while ((len = read(fd, s, left)) > 0) {
                s[len] = '\0';
                left -= len;
                s += len;

                if (endhdr >= 0) {
                        if (endhdr == 0) {
                                t = strchr(buffer, ' ');
                                if (t == NULL)
                                        continue;
                                t++;
                                if (*t != '2')
                                        break;
                        }

                        u = buffer;
                        while ((t = strchr(u, '\r')) != NULL) {
                                if (t == u) {
                                        if (*(t + 1) == '\n') {
                                                u = t + 2;
                                                endhdr = -1;
                                                break;
                                        } else
                                                t++;
                                } else if (*(t + 1) == '\n') {
                                        endhdr++;
                                        u = t + 2;
                                } else
                                        u = t + 1;
                        }
                        if (endhdr >= 0)
                                continue;
                        removed = (u - buffer) + 1;
                        memmove(buffer, u, (sizeof(buffer) - left) - removed);
                        s -= removed;
                        left += removed;
                }

                do {
                        t = strchr(buffer, '\n');
                        if (t == NULL)
                                break;

                        linenum++;
                        *t = '\0';

                        /*
                         * Remove comment and continue to the next line if
                         * the comment is at the start of the line.
                         */
                        u = strchr(buffer, '#');
                        if (u != NULL) {
                                *u = '\0';
                                if (u == buffer)
                                        continue;
                        }

                        /*
                         * Trim off tailing white spaces, will include \r
                         */
                        for (u = t - 1; (u >= buffer) && ISSPACE(*u); u--)
                                *u = '\0';

                        a = alist_new(AF_UNSPEC, buffer);
                        if (a != NULL) {
                                if (rbot != NULL)
                                        rbot->al_next = a;
                                else
                                        rtop = a;
                                rbot = a;
                        } else {
                                fprintf(stderr,
                                        "%s:%d unrecognised content:%s\n",
                                        url, linenum, buffer);
                        }

                        t++;
                        removed = t - buffer;
                        memmove(buffer, t, sizeof(buffer) - left - removed);
                        s -= removed;
                        left += removed;

                } while (1);
        }

done:
        if (myurl != NULL)
                free(myurl);
        if (fd != -1)
                close(fd);
        return (rtop);
}