[OpenSPARC-T2-DV] / verif / env / common / vera / niu_ippktgen / C / libnet / src / libnet_build_tcp.c

/*
 *  $Id: libnet_build_tcp.c,v 1.20 2005/11/29 22:14:06 carlosc Exp $
 *
 *  libnet
 *  libnet_build_tcp.c - TCP packet assembler
 *
 *  Copyright (c) 1998 - 2004 Mike D. Schiffman <mike@infonexus.com>
 *  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 */

#if (HAVE_CONFIG_H)
#include "../include/config.h"
#endif
#if (!(_WIN32) || (__CYGWIN__)) 
#include "../include/libnet.h"
#else
#include "../include/win32/libnet.h"
#endif

libnet_ptag_t
libnet_build_tcp(u_int16_t sp, u_int16_t dp, u_int32_t seq, u_int32_t ack,
u_int8_t control, u_int16_t win, u_int16_t sum, u_int16_t urg, u_int16_t len,
u_int8_t *payload, u_int32_t payload_s, libnet_t *l, libnet_ptag_t ptag)
{
    int n, offset;
    u_int32_t i, j;
    libnet_pblock_t *p, *p_data, *p_temp;
    libnet_ptag_t ptag_hold, ptag_data;
    struct libnet_tcp_hdr tcp_hdr;
    struct libnet_ipv4_hdr *ip_hdr;

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

    ptag_data = 0;                      /* for possible options */

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

    memset(&tcp_hdr, 0, sizeof(tcp_hdr));
    tcp_hdr.th_sport   = htons(sp);    /* source port */
    tcp_hdr.th_dport   = htons(dp);    /* destination port */
    tcp_hdr.th_seq     = htonl(seq);   /* sequence number */
    tcp_hdr.th_ack     = htonl(ack);   /* acknowledgement number */
    tcp_hdr.th_flags   = control;      /* control flags */
    tcp_hdr.th_x2      = 0;            /* UNUSED */
    tcp_hdr.th_off     = 5;            /* 20 byte header */

    /* check to see if there are TCP options to include */
    if (p->prev)
    {
        p_temp = p->prev;
        while ((p_temp->prev) && (p_temp->type != LIBNET_PBLOCK_TCPO_H))
        {
            p_temp = p_temp->prev;
        }
        if (p_temp->type == LIBNET_PBLOCK_TCPO_H)
        {
            /*
             *  Count up number of 32-bit words in options list, padding if
             *  neccessary.
             */
            for (i = 0, j = 0; i < p_temp->b_len; i++)
            {
                (i % 4) ? j : j++;
            }
            tcp_hdr.th_off += j;
        }
    }

    tcp_hdr.th_win     = htons(win);   /* window size */
    tcp_hdr.th_sum     = (sum ? htons(sum) : 0);   /* checksum */ 
    tcp_hdr.th_urp     = htons(urg);          /* urgent pointer */

    n = libnet_pblock_append(l, p, (u_int8_t *)&tcp_hdr, LIBNET_TCP_H);
    if (n == -1)
    {
        goto bad;
    }

    ptag_hold = ptag;
    if (ptag == LIBNET_PTAG_INITIALIZER)
    {
        ptag = libnet_pblock_update(l, p, len, LIBNET_PBLOCK_TCP_H);
    }

    /* find and set the appropriate ptag, or else use the default of 0 */
    offset = payload_s;
    if (ptag_hold && p->prev)
    {
        p_temp = p->prev;
        while (p_temp->prev &&
              (p_temp->type != LIBNET_PBLOCK_TCPDATA) &&
              (p_temp->type != LIBNET_PBLOCK_TCP_H))
        {
           p_temp = p_temp->prev;
        }

        if (p_temp->type == LIBNET_PBLOCK_TCPDATA)
        {
            ptag_data = p_temp->ptag;
            offset -=  p_temp->b_len;
            p->h_len += offset;
        }
        else
        {
            snprintf(l->err_buf, LIBNET_ERRBUF_SIZE,
				    "%s(): TCP data pblock not found\n", __func__);
        }
     }

    /* update ip_len if present */
    if (ptag_hold && p->next)
    {
        p_temp = p->next;
        while (p_temp->next && (p_temp->type != LIBNET_PBLOCK_IPV4_H))
        {
            p_temp = p_temp->next;
        }
        if (p_temp->type == LIBNET_PBLOCK_IPV4_H)
        {
            ip_hdr = (struct libnet_ipv4_hdr *)p_temp->buf;
            n = ntohs(ip_hdr->ip_len) + offset;
            ip_hdr->ip_len = htons(n);
        }
    }

    if ((payload && !payload_s) || (!payload && payload_s))
    {
        snprintf(l->err_buf, LIBNET_ERRBUF_SIZE,
			    "%s(): payload inconsistency\n", __func__);
        goto bad;
    }

    /* if there is a payload, add it in the context */
    if (payload && payload_s)
    {
        /* update ptag_data with the new payload */
        p_data = libnet_pblock_probe(l, ptag_data, payload_s,
                LIBNET_PBLOCK_TCPDATA);
        if (p_data == NULL) 
        {
            return (-1);
        }

        if (libnet_pblock_append(l, p_data, payload, payload_s) == -1)
        {
            goto bad;
        }

        if (ptag_data == LIBNET_PTAG_INITIALIZER)
        {
            if (p_data->prev->type == LIBNET_PBLOCK_TCP_H)
            {
                libnet_pblock_update(l, p_data, payload_s,
                        LIBNET_PBLOCK_TCPDATA);
                /* swap pblocks to correct the protocol order */
                libnet_pblock_swap(l, p->ptag, p_data->ptag);
            }
            else
            {
                /* update without setting this as the final pblock */
                p_data->type  =  LIBNET_PBLOCK_TCPDATA;
                p_data->ptag  =  ++(l->ptag_state);
                p_data->h_len =  payload_s;

                /* Adjust h_len for checksum. */
                p->h_len += payload_s;

                /* data was added after the initial construction */
                for (p_temp = l->protocol_blocks;
                        p_temp->type == LIBNET_PBLOCK_TCP_H ||
                        p_temp->type == LIBNET_PBLOCK_TCPO_H;
                        p_temp = p_temp->next)
                {
                    libnet_pblock_insert_before(l, p_temp->ptag, p_data->ptag);
                    break;
                }
                /* The end block needs to have its next pointer cleared. */
                l->pblock_end->next = NULL;
            }

            if (p_data->prev && p_data->prev->type == LIBNET_PBLOCK_TCPO_H)
            {
                libnet_pblock_swap(l, p_data->prev->ptag, p_data->ptag);
            }
        }
    }
    else
    {
        p_data = libnet_pblock_find(l, ptag_data);
        if (p_data) 
        {
            libnet_pblock_delete(l, p_data);
        }
    }

    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);
bad:
    libnet_pblock_delete(l, p);
    return (-1);
}


libnet_ptag_t
libnet_build_tcp_options(u_int8_t *options, u_int32_t options_s, libnet_t *l, 
libnet_ptag_t ptag)
{
    int offset, underflow;
    u_int32_t i, j, n, adj_size;
    libnet_pblock_t *p, *p_temp;
    struct libnet_ipv4_hdr *ip_hdr;
    struct libnet_tcp_hdr *tcp_hdr;

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

    underflow = 0;
    offset = 0;

    /* check options list size */
    if (options_s > LIBNET_MAXOPTION_SIZE)
    {
        snprintf(l->err_buf, LIBNET_ERRBUF_SIZE,
            "%s(): options list is too large %d\n", __func__, options_s);
        return (-1);
    }

    adj_size = options_s;
    if (adj_size % 4)
    {
        /* size of memory block with padding */
        adj_size += 4 - (options_s % 4);
    }

    /* if this pblock already exists, determine if there is a size diff */
    if (ptag)
    {
        p_temp = libnet_pblock_find(l, ptag);
        if (p_temp)
        {
            if (adj_size >= p_temp->b_len)
            {
                offset = adj_size - p_temp->b_len;
            }
            else
            {
                offset = p_temp->b_len - adj_size;
                underflow = 1;
            }
        }
    }

    /*
     *  Find the existing protocol block if a ptag is specified, or create
     *  a new one.
     */
    p = libnet_pblock_probe(l, ptag, adj_size, LIBNET_PBLOCK_TCPO_H);
    if (p == NULL)
    {
        return (-1);
    }
	
    n = libnet_pblock_append(l, p, options, adj_size);
    if (n == -1)
    {
        goto bad;
    }
	
    if (ptag && p->next)
    {
        p_temp = p->next;
        while ((p_temp->next) && (p_temp->type != LIBNET_PBLOCK_TCP_H))
        {
           p_temp = p_temp->next;
        }
        if (p_temp->type == LIBNET_PBLOCK_TCP_H)
        {
            /*
             *  Count up number of 32-bit words in options list, padding if
             *  neccessary.
             */
            for (i = 0, j = 0; i < p->b_len; i++)
            {
                (i % 4) ? j : j++;
            }
            tcp_hdr = (struct libnet_tcp_hdr *)p_temp->buf;
            tcp_hdr->th_off = j + 5;
            if (!underflow)
            {
                p_temp->h_len += offset;
            }
            else
            {
                p_temp->h_len -= offset;
            }
        }
        while ((p_temp->next) && (p_temp->type != LIBNET_PBLOCK_IPV4_H))
        {
            p_temp = p_temp->next;
        }
        if (p_temp->type == LIBNET_PBLOCK_IPV4_H)
        {
            ip_hdr = (struct libnet_ipv4_hdr *)p_temp->buf;
            if (!underflow)
            {
                ip_hdr->ip_len += htons(offset);
            }
            else
            {
                ip_hdr->ip_len -= htons(offset);
            }
        }
    }

    return (ptag ? ptag : libnet_pblock_update(l, p, adj_size,
            LIBNET_PBLOCK_TCPO_H));
bad:
    libnet_pblock_delete(l, p);
    return (-1);
}

/* EOF */
Commit	Line	Data
86530b38 AT	1	/*
	2	* $Id: libnet_build_tcp.c,v 1.20 2005/11/29 22:14:06 carlosc Exp $
	3	*
	4	* libnet
	5	* libnet_build_tcp.c - TCP packet assembler
	6	*
	7	* Copyright (c) 1998 - 2004 Mike D. Schiffman <mike@infonexus.com>
	8	* All rights reserved.
	9	*
	10	* Redistribution and use in source and binary forms, with or without
	11	* modification, are permitted provided that the following conditions
	12	* are met:
	13	* 1. Redistributions of source code must retain the above copyright
	14	* notice, this list of conditions and the following disclaimer.
	15	* 2. Redistributions in binary form must reproduce the above copyright
	16	* notice, this list of conditions and the following disclaimer in the
	17	* documentation and/or other materials provided with the distribution.
	18	*
	19	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	20	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	21	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	22	* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	23	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	24	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	25	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	26	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	27	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	28	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	29	* SUCH DAMAGE.
	30	*
	31	*/
	32
	33	#if (HAVE_CONFIG_H)
	34	#include "../include/config.h"
	35	#endif
	36	#if (!(_WIN32) \|\| (__CYGWIN__))
	37	#include "../include/libnet.h"
	38	#else
	39	#include "../include/win32/libnet.h"
	40	#endif
	41
	42	libnet_ptag_t
	43	libnet_build_tcp(u_int16_t sp, u_int16_t dp, u_int32_t seq, u_int32_t ack,
	44	u_int8_t control, u_int16_t win, u_int16_t sum, u_int16_t urg, u_int16_t len,
	45	u_int8_t payload, u_int32_t payload_s, libnet_t l, libnet_ptag_t ptag)
	46	{
	47	int n, offset;
	48	u_int32_t i, j;
	49	libnet_pblock_t p, p_data, *p_temp;
	50	libnet_ptag_t ptag_hold, ptag_data;
	51	struct libnet_tcp_hdr tcp_hdr;
	52	struct libnet_ipv4_hdr *ip_hdr;
	53
	54	if (l == NULL)
	55	{
	56	return (-1);
	57	}
	58
	59	ptag_data = 0; /* for possible options */
	60
	61	/*
	62	* Find the existing protocol block if a ptag is specified, or create
	63	* a new one.
	64	*/
65	p = libnet_pblock_probe(l, ptag, LIBNET_TCP_H, LIBNET_PBLOCK_TCP_H);
66	if (p == NULL)
67	{
68	return (-1);
69	}
70
71	memset(&tcp_hdr, 0, sizeof(tcp_hdr));
72	tcp_hdr.th_sport = htons(sp); /* source port */
73	tcp_hdr.th_dport = htons(dp); /* destination port */
74	tcp_hdr.th_seq = htonl(seq); /* sequence number */
75	tcp_hdr.th_ack = htonl(ack); /* acknowledgement number */
76	tcp_hdr.th_flags = control; /* control flags */
77	tcp_hdr.th_x2 = 0; /* UNUSED */
78	tcp_hdr.th_off = 5; /* 20 byte header */
79
80	/* check to see if there are TCP options to include */
81	if (p->prev)
82	{
83	p_temp = p->prev;
84	while ((p_temp->prev) && (p_temp->type != LIBNET_PBLOCK_TCPO_H))
85	{
86	p_temp = p_temp->prev;
87	}
88	if (p_temp->type == LIBNET_PBLOCK_TCPO_H)
89	{
90	/*
91	* Count up number of 32-bit words in options list, padding if
92	* neccessary.
93	*/
94	for (i = 0, j = 0; i < p_temp->b_len; i++)
95	{
96	(i % 4) ? j : j++;
97	}
98	tcp_hdr.th_off += j;
99	}
100	}
101
102	tcp_hdr.th_win = htons(win); /* window size */
103	tcp_hdr.th_sum = (sum ? htons(sum) : 0); /* checksum */
104	tcp_hdr.th_urp = htons(urg); /* urgent pointer */
105
106	n = libnet_pblock_append(l, p, (u_int8_t *)&tcp_hdr, LIBNET_TCP_H);
107	if (n == -1)
108	{
109	goto bad;
110	}
111
112	ptag_hold = ptag;
113	if (ptag == LIBNET_PTAG_INITIALIZER)
114	{
115	ptag = libnet_pblock_update(l, p, len, LIBNET_PBLOCK_TCP_H);
116	}
117
118	/* find and set the appropriate ptag, or else use the default of 0 */
119	offset = payload_s;
120	if (ptag_hold && p->prev)
121	{
122	p_temp = p->prev;
123	while (p_temp->prev &&
124	(p_temp->type != LIBNET_PBLOCK_TCPDATA) &&
125	(p_temp->type != LIBNET_PBLOCK_TCP_H))
126	{
127	p_temp = p_temp->prev;
128	}
129
130	if (p_temp->type == LIBNET_PBLOCK_TCPDATA)
131	{
132	ptag_data = p_temp->ptag;
133	offset -= p_temp->b_len;
134	p->h_len += offset;
135	}
136	else
137	{
138	snprintf(l->err_buf, LIBNET_ERRBUF_SIZE,
139	"%s(): TCP data pblock not found\n", __func__);
140	}
141	}
142
143	/* update ip_len if present */
144	if (ptag_hold && p->next)
145	{
146	p_temp = p->next;
147	while (p_temp->next && (p_temp->type != LIBNET_PBLOCK_IPV4_H))
148	{
149	p_temp = p_temp->next;
150	}
151	if (p_temp->type == LIBNET_PBLOCK_IPV4_H)
152	{
153	ip_hdr = (struct libnet_ipv4_hdr *)p_temp->buf;
154	n = ntohs(ip_hdr->ip_len) + offset;
155	ip_hdr->ip_len = htons(n);
156	}
157	}
158
159	if ((payload && !payload_s) \|\| (!payload && payload_s))
160	{
161	snprintf(l->err_buf, LIBNET_ERRBUF_SIZE,
162	"%s(): payload inconsistency\n", __func__);
163	goto bad;
164	}
165
166	/* if there is a payload, add it in the context */
167	if (payload && payload_s)
168	{
169	/* update ptag_data with the new payload */
170	p_data = libnet_pblock_probe(l, ptag_data, payload_s,
171	LIBNET_PBLOCK_TCPDATA);
172	if (p_data == NULL)
173	{
174	return (-1);
175	}
176
177	if (libnet_pblock_append(l, p_data, payload, payload_s) == -1)
178	{
179	goto bad;
180	}
181
182	if (ptag_data == LIBNET_PTAG_INITIALIZER)
183	{
184	if (p_data->prev->type == LIBNET_PBLOCK_TCP_H)
185	{
186	libnet_pblock_update(l, p_data, payload_s,
187	LIBNET_PBLOCK_TCPDATA);
188	/* swap pblocks to correct the protocol order */
189	libnet_pblock_swap(l, p->ptag, p_data->ptag);
190	}
191	else
192	{
193	/* update without setting this as the final pblock */
194	p_data->type = LIBNET_PBLOCK_TCPDATA;
195	p_data->ptag = ++(l->ptag_state);
196	p_data->h_len = payload_s;
197
198	/* Adjust h_len for checksum. */
199	p->h_len += payload_s;
200
201	/* data was added after the initial construction */
202	for (p_temp = l->protocol_blocks;
203	p_temp->type == LIBNET_PBLOCK_TCP_H \|\|
204	p_temp->type == LIBNET_PBLOCK_TCPO_H;
205	p_temp = p_temp->next)
206	{
207	libnet_pblock_insert_before(l, p_temp->ptag, p_data->ptag);
208	break;
209	}
210	/* The end block needs to have its next pointer cleared. */
211	l->pblock_end->next = NULL;
212	}
213
214	if (p_data->prev && p_data->prev->type == LIBNET_PBLOCK_TCPO_H)
215	{
216	libnet_pblock_swap(l, p_data->prev->ptag, p_data->ptag);
217	}
218	}
219	}
220	else
221	{
222	p_data = libnet_pblock_find(l, ptag_data);
223	if (p_data)
224	{
225	libnet_pblock_delete(l, p_data);
226	}
227	}
228
229	if (sum == 0)
230	{
231	/*
232	* If checksum is zero, by default libnet will compute a checksum
233	* for the user. The programmer can override this by calling
234	* libnet_toggle_checksum(l, ptag, 1);
235	*/
236	libnet_pblock_setflags(p, LIBNET_PBLOCK_DO_CHECKSUM);
237	}
238	return (ptag);
239	bad:
240	libnet_pblock_delete(l, p);
241	return (-1);
242	}
243
244
245	libnet_ptag_t
246	libnet_build_tcp_options(u_int8_t options, u_int32_t options_s, libnet_t l,
247	libnet_ptag_t ptag)
248	{
249	int offset, underflow;
250	u_int32_t i, j, n, adj_size;
251	libnet_pblock_t p, p_temp;
252	struct libnet_ipv4_hdr *ip_hdr;
253	struct libnet_tcp_hdr *tcp_hdr;
254
255	if (l == NULL)
256	{
257	return (-1);
258	}
259
260	underflow = 0;
261	offset = 0;
262
263	/* check options list size */
264	if (options_s > LIBNET_MAXOPTION_SIZE)
265	{
266	snprintf(l->err_buf, LIBNET_ERRBUF_SIZE,
267	"%s(): options list is too large %d\n", __func__, options_s);
268	return (-1);
269	}
270
271	adj_size = options_s;
272	if (adj_size % 4)
273	{
274	/* size of memory block with padding */
275	adj_size += 4 - (options_s % 4);
276	}
277
278	/* if this pblock already exists, determine if there is a size diff */
279	if (ptag)
280	{
281	p_temp = libnet_pblock_find(l, ptag);
282	if (p_temp)
283	{
284	if (adj_size >= p_temp->b_len)
285	{
286	offset = adj_size - p_temp->b_len;
287	}
288	else
289	{
290	offset = p_temp->b_len - adj_size;
291	underflow = 1;
292	}
293	}
294	}
295
296	/*
297	* Find the existing protocol block if a ptag is specified, or create
298	* a new one.
299	*/
300	p = libnet_pblock_probe(l, ptag, adj_size, LIBNET_PBLOCK_TCPO_H);
301	if (p == NULL)
302	{
303	return (-1);
304	}
305
306	n = libnet_pblock_append(l, p, options, adj_size);
307	if (n == -1)
308	{
309	goto bad;
310	}
311
312	if (ptag && p->next)
313	{
314	p_temp = p->next;
315	while ((p_temp->next) && (p_temp->type != LIBNET_PBLOCK_TCP_H))
316	{
317	p_temp = p_temp->next;
318	}
319	if (p_temp->type == LIBNET_PBLOCK_TCP_H)
320	{
321	/*
322	* Count up number of 32-bit words in options list, padding if
323	* neccessary.
324	*/
325	for (i = 0, j = 0; i < p->b_len; i++)
326	{
327	(i % 4) ? j : j++;
328	}
329	tcp_hdr = (struct libnet_tcp_hdr *)p_temp->buf;
330	tcp_hdr->th_off = j + 5;
331	if (!underflow)
332	{
333	p_temp->h_len += offset;
334	}
335	else
336	{
337	p_temp->h_len -= offset;
338	}
339	}
340	while ((p_temp->next) && (p_temp->type != LIBNET_PBLOCK_IPV4_H))
341	{
342	p_temp = p_temp->next;
343	}
344	if (p_temp->type == LIBNET_PBLOCK_IPV4_H)
345	{
346	ip_hdr = (struct libnet_ipv4_hdr *)p_temp->buf;
347	if (!underflow)
348	{
349	ip_hdr->ip_len += htons(offset);
350	}
351	else
352	{
353	ip_hdr->ip_len -= htons(offset);
354	}
355	}
356	}
357
358	return (ptag ? ptag : libnet_pblock_update(l, p, adj_size,
359	LIBNET_PBLOCK_TCPO_H));
360	bad:
361	libnet_pblock_delete(l, p);
362	return (-1);
363	}
364
365	/* EOF */