libnet_build_icmp.c

tcp数据流重放工具

    p = NULL;
    /* payload refers to the payload in the original IP header */
    if ((payload && !payload_s) || (!payload && payload_s))
    {
         snprintf(l->err_buf, LIBNET_ERRBUF_SIZE,
			     "%s(): payload inconsistency\n", __func__);
        goto bad;
    }

    /*
     *  Build the original IPv4 header in its own pblock.  We stick the
     *  payload here.
     */
    ipv4 = libnet_build_ipv4(orig_len, orig_tos, orig_id, orig_frag, orig_ttl,
        orig_prot, orig_check, orig_src, orig_dst, payload, payload_s, l, 0);

    if (ipv4 == -1)
    {
        /* error set elsewhere */
        return (-1);
    }

    if (orig_check == 0)
    {
       int c = 0;
       l->aligner = 8 - (l->link_offset % 8);
       q = libnet_pblock_find(l, ipv4);
       c = libnet_do_checksum(l, q->buf, libnet_pblock_p2p(q->type),
                              q->h_len);
       if (c == -1)
       {
           /* err msg set in libnet_do_checksum() */
           return (-1);
       }
    }

    /*
     * Now we can build the ICMP part of the packet
     */
    n = LIBNET_ICMPV4_UNREACH_H;        /* size of memory block */
    /* hl for checksum */
    h = LIBNET_ICMPV4_UNREACH_H + LIBNET_IPV4_H + payload_s;

    /*
     *  Find the existing protocol block if a ptag is specified, or create
     *  a new one.
     */
    p = libnet_pblock_probe(l, ptag, n, LIBNET_PBLOCK_ICMPV4_UNREACH_H);
    if (p == NULL)
    {
        return (-1);
    }

	memset(&icmp_hdr, 0, sizeof(icmp_hdr));
	icmp_hdr.icmp_type = type;          /* packet type */
    icmp_hdr.icmp_code = code;          /* packet code */
    icmp_hdr.icmp_sum  = sum;           /* checksum */
    icmp_hdr.icmp_id   = 0;             /* must be 0 */
    icmp_hdr.icmp_seq  = 0;             /* must be 0 */

    n = libnet_pblock_append(l, p, (u_int8_t *)&icmp_hdr,
            LIBNET_ICMPV4_UNREACH_H);
    if (n == -1)
    {
        /* error set elsewhere */
        goto bad;
    }

    if (sum == 0)
    {
        /*
         *  If checksum is zero, by default libnet will compute a checksum
         *  for the user.  The programmer can override this by calling
         *  libnet_toggle_checksum(l, ptag, 1);
         */
        libnet_pblock_setflags(p, LIBNET_PBLOCK_DO_CHECKSUM);
    }
    return (ptag ? ptag : libnet_pblock_update(l, p, h,
            LIBNET_PBLOCK_ICMPV4_UNREACH_H));
bad:
    libnet_pblock_delete(l, p);
    return (-1);
}


libnet_ptag_t
libnet_build_icmpv4_timeexceed(u_int8_t type, u_int8_t code, u_int16_t sum,
            u_int16_t orig_len, u_int8_t orig_tos, u_int16_t orig_id,
            u_int16_t orig_frag, u_int8_t orig_ttl, u_int8_t orig_prot,
            u_int16_t orig_check, u_int32_t orig_src, u_int32_t orig_dst,
            u_int8_t *payload, u_int32_t payload_s, libnet_t *l, libnet_ptag_t ptag)
{
    u_int32_t n, h;
    libnet_ptag_t ipv4;
    libnet_pblock_t *p, *q;
    struct libnet_icmpv4_hdr icmp_hdr;

    if (l == NULL)
    { 
        return (-1);
    } 

    p = NULL;
    /* payload refers to the payload in the original IP header */
    if ((payload && !payload_s) || (!payload && payload_s))
    {
         snprintf(l->err_buf, LIBNET_ERRBUF_SIZE,
			     "%s(): payload inconsistency\n", __func__);
        goto bad;
    }

    /*
     *  Build the original IPv4 header in its own pblock.  We stick the
     *  payload here.
     */
    ipv4 = libnet_build_ipv4(orig_len, orig_tos, orig_id, orig_frag, orig_ttl,
        orig_prot, orig_check, orig_src, orig_dst, payload, payload_s, l, 0);

    if (ipv4 == -1)
    {
        /* error set elsewhere */
	return (-1);
    }

    if (orig_check == 0)
    {
       int c = 0;
       l->aligner = 8 - (l->link_offset % 8);
       q = libnet_pblock_find(l, ipv4);
       c = libnet_do_checksum(l, q->buf, libnet_pblock_p2p(q->type),
                              q->h_len);
       if (c == -1)
       {
           /* err msg set in libnet_do_checksum() */
           return (-1);
       }
    }

    /* size of memory block */
    n = LIBNET_ICMPV4_TIMXCEED_H;
    /* hl for checksum */
    h = LIBNET_ICMPV4_TIMXCEED_H + LIBNET_IPV4_H + payload_s;

    /*
     *  Find the existing protocol block if a ptag is specified, or create
     *  a new one.
     */
    p = libnet_pblock_probe(l, ptag, n, LIBNET_PBLOCK_ICMPV4_TIMXCEED_H);
    if (p == NULL)
    {
        return (-1);
    }

	memset(&icmp_hdr, 0, sizeof(icmp_hdr));
	icmp_hdr.icmp_type = type;          /* packet type */
    icmp_hdr.icmp_code = code;          /* packet code */
    icmp_hdr.icmp_sum  = sum;           /* checksum */
    icmp_hdr.icmp_id   = 0;             /* must be 0 */
    icmp_hdr.icmp_seq  = 0;             /* must be 0 */

    n = libnet_pblock_append(l, p, (u_int8_t *)&icmp_hdr,
            LIBNET_ICMPV4_TIMXCEED_H);
    if (n == -1)
    {
        goto bad;
    }
 
    if (sum == 0)
    {
        /*
         *  If checksum is zero, by default libnet will compute a checksum
         *  for the user.  The programmer can override this by calling
         *  libnet_toggle_checksum(l, ptag, 1);
         */
        libnet_pblock_setflags(p, LIBNET_PBLOCK_DO_CHECKSUM);
    }
    return (ptag ? ptag : libnet_pblock_update(l, p, h,
            LIBNET_PBLOCK_ICMPV4_TIMXCEED_H));
bad:
    libnet_pblock_delete(l, p);
    return (-1);
}


libnet_ptag_t
libnet_build_icmpv4_redirect(u_int8_t type, u_int8_t code, u_int16_t sum,
            u_int32_t gateway, u_int16_t orig_len, u_int8_t orig_tos, u_int16_t orig_id,
            u_int16_t orig_frag, u_int8_t orig_ttl, u_int8_t orig_prot,
            u_int16_t orig_check, u_int32_t orig_src, u_int32_t orig_dst,
            u_int8_t *payload, u_int32_t payload_s, libnet_t *l, libnet_ptag_t ptag)

{
    u_int32_t n, h;
    libnet_ptag_t ipv4;
    libnet_pblock_t *p, *q;
    struct libnet_icmpv4_hdr icmp_hdr;

    if (l == NULL)
    { 
        return (-1);
    } 

    p = NULL;
    /* payload refers to the payload in the original IP header */
    if ((payload && !payload_s) || (!payload && payload_s))
    {
         snprintf(l->err_buf, LIBNET_ERRBUF_SIZE,
			     "%s(): payload inconsistency\n", __func__);
        goto bad;
    }

    /*
     *  Build the original IPv4 header in its own pblock.  We stick the
     *  payload here.
     */
    ipv4 = libnet_build_ipv4(orig_len, orig_tos, orig_id, orig_frag, orig_ttl,
        orig_prot, orig_check, orig_src, orig_dst, payload, payload_s, l, 0);

    if (ipv4 == -1)
    {
       /* error set elsewhere */
       return (-1);
    }

    if (orig_check == 0)
    {
       int c = 0;
       l->aligner = 8 - (l->link_offset % 8);
       q = libnet_pblock_find(l, ipv4);
       c = libnet_do_checksum(l, q->buf, libnet_pblock_p2p(q->type),
                              q->h_len);
       if (c == -1)
       {
           /* err msg set in libnet_do_checksum() */
           return (-1);
       }
    }

    n = LIBNET_ICMPV4_REDIRECT_H;               /* size of memory block */
    /* hl for checksum */
    h = LIBNET_ICMPV4_REDIRECT_H + LIBNET_IPV4_H + payload_s;

    /*
     *  Find the existing protocol block if a ptag is specified, or create
     *  a new one.
     */
    p = libnet_pblock_probe(l, ptag, n, LIBNET_PBLOCK_ICMPV4_REDIRECT_H);
    if (p == NULL)
    {
        return (-1);
    }

	memset(&icmp_hdr, 0, sizeof(icmp_hdr));
	icmp_hdr.icmp_type      = type;             /* packet type */
    icmp_hdr.icmp_code      = code;             /* packet code */
    icmp_hdr.icmp_sum       = sum;              /* checksum */
    icmp_hdr.hun.gateway    = htonl(gateway);   /* gateway address */

    n = libnet_pblock_append(l, p, (u_int8_t *)&icmp_hdr, 
                             LIBNET_ICMPV4_REDIRECT_H);
    if (n == -1)
    {
        goto bad;
    }
 
    if (sum == 0)
    {
        /*
         *  If checksum is zero, by default libnet will compute a checksum
         *  for the user.  The programmer can override this by calling
         *  libnet_toggle_checksum(l, ptag, 1);
         */
        libnet_pblock_setflags(p, LIBNET_PBLOCK_DO_CHECKSUM);
    }
    return (ptag ? ptag : libnet_pblock_update(l, p, h,
            LIBNET_PBLOCK_ICMPV4_REDIRECT_H));
bad:
    libnet_pblock_delete(l, p);
    return (-1);
}


/* EOF */