usr.sbin/snoop/snoop_http.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright (c) 1996-1998,2001 by Sun Microsystems, Inc.
 * All rights reserved.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

/*
 * Protocol interpreter for the Hypertext Transfer Protocol (HTTP)
 *
 * Relevant standards:
 *  Berners-Lee, T., et al: Hypertext Transfer Protocol -- HTTP/1.0.
 *      RFC 1945, May 1996
 *  Fielding, R., et al: Hypertext Transfer Protocol -- HTTP/1.1.
 *      RFC 2068, June 1999
 */

#include <netinet/in.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include "snoop.h"

#define CR  13          /* "carriage return" character */
#define LF  10          /* "line feed" character */

/*
 * Summary lines: packet contents starting with less than MINCHARS
 * printable characters will not be printed. MAXCHARS is the maximum
 * number of characters printed.
 * Detail lines: NLINES is the maximum number of content lines to print
 */
#define MINCHARS    10
#define MAXCHARS    80
#define NLINES      5

#define MIN(a, b) (((a) < (b)) ? (a) : (b))

static int printable(const char *line, const char *endp);

int
interpret_http(int flags, char *line, int fraglen)
{
    char *p, *q, *endp;
    int c;
    int lineno;

    endp = line + fraglen;

    if (flags & F_SUM) {
        c = printable(line, endp - 1);
        if (c < MINCHARS) {
            (void) snprintf(get_sum_line(), MAXLINE,
                "HTTP (body)");
        } else {
            (void) snprintf(get_sum_line(), MAXLINE,
                "HTTP %.*s", MIN(c, MAXCHARS), line);
        }
    }

    if (flags & F_DTAIL) {
        show_header("HTTP: ", "HyperText Transfer Protocol", fraglen);
        show_space();

        lineno = 0;
        for (p = line; p < endp && lineno < NLINES; p = q + 1) {
            c = printable(p, endp - 1);

            /* stop if no printables, except if at line end */
            if (c == 0 && *p != CR && *p != LF)
                break;

            /*
             * A line may be terminated either by an CR LF sequence
             * (DOS, Mac), or by LF alone
             */

            q = memchr(p, CR, (endp - p));
            if (q != NULL) {
                if (q < endp - 1 && q[1] == LF)
                ++q;    /* ignore subsequent LF character */
            } else {
                q = memchr(p, LF, (endp - p));
                /* no CR/LF: use end of buffer */
                if (q == NULL)
                q = endp - 1;
            }

            /* truncate lines containing non-printable characters */
            (void) snprintf(get_line(0, c), get_line_remain(),
                "%.*s", c, p);
            ++lineno;
        }

        if (p < endp)   /* there was more data to be printed */
            (void) snprintf(get_line(0, 5), get_line_remain(),
                "[...]");

        show_space();
    }

    return (fraglen);
}

/*
 * Return the length of the initial string starting with "startp" and
 * ending with "endp" (inclusively) consisting only of printable
 * characters.
 */

static int
printable(const char *startp, const char *endp)
{
    const char *p = startp;

    while (p <= endp && (isprint(*p) || *p == '\t'))
        p++;

    return (p - startp);
}