/*
* $Id: libnet_build_ip.c,v 1.1.1.3 2023/09/27 11:11:38 misho Exp $
*
* libnet
* libnet_build_ip.c - IP 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.
*
*/
#include "common.h"
/* TODO len - should be calculated if -1 */
libnet_ptag_t
libnet_build_ipv4(uint16_t ip_len, uint8_t tos, uint16_t id, uint16_t frag,
uint8_t ttl, uint8_t prot, uint16_t sum, uint32_t src, uint32_t dst,
const uint8_t *payload, uint32_t payload_s, libnet_t *l, libnet_ptag_t ptag)
{
uint32_t n = LIBNET_IPV4_H; /* size of memory block */
libnet_pblock_t *p, *p_data, *p_temp;
struct libnet_ipv4_hdr ip_hdr;
libnet_ptag_t ptag_data = 0; /* used if there is ipv4 payload */
libnet_ptag_t ptag_hold;
if (l == NULL)
{
return (-1);
}
/*
* Find the existing protocol block if a ptag is specified, or create
* a new one.
*/
p = libnet_pblock_probe(l, ptag, n, LIBNET_PBLOCK_IPV4_H);
if (p == NULL)
{
return (-1);
}
memset(&ip_hdr, 0, sizeof(ip_hdr));
ip_hdr.ip_v = 4; /* version 4 */
ip_hdr.ip_hl = 5; /* 20 byte header, measured in 32-bit words */
/* check to see if there are IP options to include */
if (p->prev)
{
if (p->prev->type == LIBNET_PBLOCK_IPO_H)
{
/* IPO block's length must be multiple of 4, or it's incorrectly
* padded, in which case there is no "correct" IP header length,
* it will too short or too long, we choose too short.
*/
ip_hdr.ip_hl += p->prev->b_len / 4;
}
}
/* Note that p->h_len is not adjusted. This seems a bug, but it is because
* it is not used! libnet_do_checksum() is passed the h_len (as `len'),
* but for IPPROTO_IP it is ignored in favor of the ip_hl.
*/
ip_hdr.ip_tos = tos; /* IP tos */
ip_hdr.ip_len = htons(ip_len); /* total length */
ip_hdr.ip_id = htons(id); /* IP ID */
ip_hdr.ip_off = htons(frag); /* fragmentation flags */
ip_hdr.ip_ttl = ttl; /* time to live */
ip_hdr.ip_p = prot; /* transport protocol */
ip_hdr.ip_sum = (sum ? htons(sum) : 0); /* checksum */
ip_hdr.ip_src.s_addr = src; /* source ip */
ip_hdr.ip_dst.s_addr = dst; /* destination ip */
n = libnet_pblock_append(l, p, (uint8_t *)&ip_hdr, LIBNET_IPV4_H);
if (n == -1)
{
goto bad;
}
/* save the original ptag value */
ptag_hold = ptag;
if (ptag == LIBNET_PTAG_INITIALIZER)
{
ptag = libnet_pblock_update(l, p, LIBNET_IPV4_H, LIBNET_PBLOCK_IPV4_H);
}
/* find and set the appropriate ptag, or else use the default of 0 */
/* When updating the ipv4 block, we need to find the data block, and
* adjust our ip_offset if the new payload size is different from what
* it used to be.
*/
if (ptag_hold && p->prev)
{
p_temp = p->prev;
while (p_temp->prev &&
(p_temp->type != LIBNET_PBLOCK_IPDATA) &&
(p_temp->type != LIBNET_PBLOCK_IPV4_H))
{
p_temp = p_temp->prev;
}
if (p_temp->type == LIBNET_PBLOCK_IPDATA)
{
ptag_data = p_temp->ptag;
}
else
{
snprintf(l->err_buf, LIBNET_ERRBUF_SIZE,
"%s(): IPv4 data pblock not found", __func__);
}
}
if (payload_s && !payload)
{
snprintf(l->err_buf, LIBNET_ERRBUF_SIZE,
"%s(): payload inconsistency", __func__);
goto bad;
}
if (payload_s)
{
/* update ptag_data with the new payload */
/* on create:
* b_len = payload_s
* l->total_size += b_len
* h_len = 0
* on update:
* b_len = payload_s
* h_len += <diff in size between new b_len and old b_len>
* increments if if b_len goes up, down if it goes down
* in either case:
* copied = 0
*/
p_data = libnet_pblock_probe(l, ptag_data, payload_s,
LIBNET_PBLOCK_IPDATA);
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)
{
/* IPDATA's h_len gets set to payload_s in both branches */
if (p_data->prev->type == LIBNET_PBLOCK_IPV4_H)
{
libnet_pblock_update(l, p_data, payload_s,
LIBNET_PBLOCK_IPDATA);
/* swap pblocks to correct the protocol order */
libnet_pblock_swap(l, p->ptag, p_data->ptag);
}
else
{
/* SR - I'm not sure how to reach this code. Maybe if the first
* time we added an ipv4 block, there was no payload, but when
* we modify the block the next time, we have payload?
*/
/* update without setting this as the final pblock */
p_data->type = LIBNET_PBLOCK_IPDATA;
p_data->ptag = ++(l->ptag_state);
p_data->h_len = payload_s; /* TODO dead code, data blocks don't have headers */
/* data was added after the initial construction */
for (p_temp = l->protocol_blocks;
p_temp->type == LIBNET_PBLOCK_IPV4_H ||
p_temp->type == LIBNET_PBLOCK_IPO_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_IPO_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);
}
else
{
/*
* XXX - When this completes successfully, libnet errbuf contains
* an error message so to come correct, we'll clear it.
*/
memset(l->err_buf, 0, sizeof (l->err_buf));
}
}
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_autobuild_ipv4(uint16_t len, uint8_t prot, uint32_t dst, libnet_t *l)
{
uint32_t n, i, j, src;
uint16_t h;
libnet_pblock_t *p;
libnet_ptag_t ptag;
struct libnet_ipv4_hdr ip_hdr;
if (l == NULL)
{
return (-1);
}
n = LIBNET_IPV4_H; /* size of memory block */
h = len; /* header length */
ptag = LIBNET_PTAG_INITIALIZER;
src = libnet_get_ipaddr4(l);
if (src == -1)
{
/* err msg set in libnet_get_ipaddr() */
return (-1);
}
/*
* Create a new pblock.
*/
p = libnet_pblock_probe(l, ptag, n, LIBNET_PBLOCK_IPV4_H);
if (p == NULL)
{
return (-1);
}
memset(&ip_hdr, 0, sizeof(ip_hdr));
ip_hdr.ip_v = 4; /* version 4 */
ip_hdr.ip_hl = 5; /* 20 byte header */
/* check to see if there are IP options to include */
if (p->prev)
{
if (p->prev->type == LIBNET_PBLOCK_IPO_H)
{
/*
* Count up number of 32-bit words in options list, padding if
* neccessary.
*/
for (i = 0, j = 0; i < p->prev->b_len; i++)
{
(i % 4) ? j : j++;
}
ip_hdr.ip_hl += j;
}
}
ip_hdr.ip_tos = 0; /* IP tos */
ip_hdr.ip_len = htons(h); /* total length */
ip_hdr.ip_id = htons((l->ptag_state) & 0x0000ffff); /* IP ID */
ip_hdr.ip_off = 0; /* fragmentation flags */
ip_hdr.ip_ttl = 64; /* time to live */
ip_hdr.ip_p = prot; /* transport protocol */
ip_hdr.ip_sum = 0; /* checksum */
ip_hdr.ip_src.s_addr = src; /* source ip */
ip_hdr.ip_dst.s_addr = dst; /* destination ip */
n = libnet_pblock_append(l, p, (uint8_t *)&ip_hdr, LIBNET_IPV4_H);
if (n == -1)
{
goto bad;
}
libnet_pblock_setflags(p, LIBNET_PBLOCK_DO_CHECKSUM);
ptag = libnet_pblock_update(l, p, LIBNET_IPV4_H, LIBNET_PBLOCK_IPV4_H);
return (ptag);
bad:
libnet_pblock_delete(l, p);
return (-1);
}
libnet_ptag_t
libnet_build_ipv4_options(const uint8_t *options, uint32_t options_s, libnet_t *l,
libnet_ptag_t ptag)
{
int options_size_increase = 0; /* increase will be negative if it's a decrease */
uint32_t n, adj_size;
libnet_pblock_t *p, *p_temp;
struct libnet_ipv4_hdr *ip_hdr;
if (l == NULL)
{
return (-1);
}
/* check options list size */
if (options_s > LIBNET_MAXOPTION_SIZE)
{
snprintf(l->err_buf, LIBNET_ERRBUF_SIZE,
"%s(): options list is too large %d", __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)
{
options_size_increase = adj_size - p_temp->b_len;
}
}
/* If we aren't modifying an options block, we are pushing a new one, and
* since it must be pushed before the IPv4 block is pushed, there is no
* need to remember that options size has "increased".
*/
/*
* 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_IPO_H);
if (p == NULL)
{
return (-1);
}
/* append options */
n = libnet_pblock_append(l, p, options, options_s);
if (n == -1)
{
goto bad;
}
/* append padding */
n = libnet_pblock_append(l, p, (uint8_t*)"\0\0\0", adj_size - options_s);
if (n == -1)
{
goto bad;
}
if (ptag && p->next)
{
p_temp = p->next;
/* fix the IP header sizes */
if (p_temp->type == LIBNET_PBLOCK_IPV4_H)
{
ip_hdr = (struct libnet_ipv4_hdr *) p_temp->buf;
ip_hdr->ip_hl = 5 + adj_size / 4; /* 4 bits wide, so no byte order concerns */
ip_hdr->ip_len = htons(ntohs(ip_hdr->ip_len) + options_size_increase);
p_temp->h_len = ip_hdr->ip_hl * 4; /* Dead code, h_len isn't used for IPv4 block */
}
}
return (ptag ? ptag : libnet_pblock_update(l, p, adj_size,
LIBNET_PBLOCK_IPO_H));
bad:
libnet_pblock_delete(l, p);
return (-1);
}
libnet_ptag_t
libnet_build_ipv6(uint8_t tc, uint32_t fl, uint16_t len, uint8_t nh,
uint8_t hl, struct libnet_in6_addr src, struct libnet_in6_addr dst,
const uint8_t *payload, uint32_t payload_s, libnet_t *l, libnet_ptag_t ptag)
{
uint32_t n;
libnet_pblock_t *p;
struct libnet_ipv6_hdr ip_hdr;
if (l == NULL)
{
return (-1);
}
n = LIBNET_IPV6_H + payload_s; /* size of memory block */
if (LIBNET_IPV6_H + payload_s > IP_MAXPACKET)
{
snprintf(l->err_buf, LIBNET_ERRBUF_SIZE,
"%s(): IP packet too large", __func__);
return (-1);
}
/*
* Find the existing protocol block if a ptag is specified, or create
* a new one.
*/
p = libnet_pblock_probe(l, ptag, n, LIBNET_PBLOCK_IPV6_H);
if (p == NULL)
{
return (-1);
}
memset(&ip_hdr, 0, sizeof(ip_hdr));
ip_hdr.ip_flags[0] = (0x06 << 4) | ((tc & 0xF0) >> 4);
ip_hdr.ip_flags[1] = ((tc & 0x0F) << 4) | ((fl & 0xF0000) >> 16);
ip_hdr.ip_flags[2] = (fl & 0x0FF00) >> 8;
ip_hdr.ip_flags[3] = fl & 0x000FF;
ip_hdr.ip_len = htons(len);
ip_hdr.ip_nh = nh;
ip_hdr.ip_hl = hl;
ip_hdr.ip_src = src;
ip_hdr.ip_dst = dst;
n = libnet_pblock_append(l, p, (uint8_t *)&ip_hdr, LIBNET_IPV6_H);
if (n == -1)
{
goto bad;
}
/* boilerplate payload sanity check / append macro */
LIBNET_DO_PAYLOAD(l, p);
/* no checksum for IPv6 */
ptag = ptag ? ptag : libnet_pblock_update(l, p, LIBNET_IPV6_H,
LIBNET_PBLOCK_IPV6_H);
return ptag;
bad:
libnet_pblock_delete(l, p);
return (-1);
}
libnet_ptag_t
libnet_build_ipv6_frag(uint8_t nh, uint8_t reserved, uint16_t frag,
uint32_t id, const uint8_t *payload, uint32_t payload_s, libnet_t *l,
libnet_ptag_t ptag)
{
uint32_t n;
uint16_t h;
libnet_pblock_t *p;
struct libnet_ipv6_frag_hdr ipv6_frag_hdr;
if (l == NULL)
{
return (-1);
}
n = LIBNET_IPV6_FRAG_H + payload_s;
h = 0;
if (LIBNET_IPV6_FRAG_H + payload_s > IP_MAXPACKET)
{
snprintf(l->err_buf, LIBNET_ERRBUF_SIZE,
"%s(): IP packet too large", __func__);
return (-1);
}
/*
* Find the existing protocol block if a ptag is specified, or create
* a new one.
*/
p = libnet_pblock_probe(l, ptag, n, LIBNET_PBLOCK_IPV6_FRAG_H);
if (p == NULL)
{
return (-1);
}
memset(&ipv6_frag_hdr, 0 , sizeof(ipv6_frag_hdr));
ipv6_frag_hdr.ip_nh = nh;
ipv6_frag_hdr.ip_reserved = reserved;
ipv6_frag_hdr.ip_frag = frag;
ipv6_frag_hdr.ip_id = id;
/*
* Appened the protocol unit to the list.
*/
n = libnet_pblock_append(l, p, (uint8_t *)&ipv6_frag_hdr,
LIBNET_IPV6_FRAG_H);
if (n == -1)
{
goto bad;
}
/* boilerplate payload sanity check / append macro */
LIBNET_DO_PAYLOAD(l, p);
/*
* Update the protocol block's meta information and return the protocol
* tag id of this pblock. This tag will be used to locate the pblock
* in order to modify the protocol header in subsequent calls.
*/
return (ptag ? ptag : libnet_pblock_update(l, p, h,
LIBNET_PBLOCK_IPV6_FRAG_H));
bad:
libnet_pblock_delete(l, p);
return (-1);
}
libnet_ptag_t
libnet_build_ipv6_routing(uint8_t nh, uint8_t len, uint8_t rtype,
uint8_t segments, const uint8_t *payload, uint32_t payload_s, libnet_t *l,
libnet_ptag_t ptag)
{
uint32_t n;
uint16_t h;
libnet_pblock_t *p;
struct libnet_ipv6_routing_hdr ipv6_routing_hdr;
if (l == NULL)
{
return (-1);
}
/* Important: IPv6 routing header routes are specified using the payload
* interface!
*/
n = LIBNET_IPV6_ROUTING_H + payload_s;
h = 0;
if (LIBNET_IPV6_ROUTING_H + payload_s > IP_MAXPACKET)
{
snprintf(l->err_buf, LIBNET_ERRBUF_SIZE,
"%s(): IP packet too large", __func__);
return (-1);
}
/*
* Find the existing protocol block if a ptag is specified, or create
* a new one.
*/
p = libnet_pblock_probe(l, ptag, n, LIBNET_PBLOCK_IPV6_ROUTING_H);
if (p == NULL)
{
return (-1);
}
memset(&ipv6_routing_hdr, 0 , sizeof(ipv6_routing_hdr));
ipv6_routing_hdr.ip_nh = nh;
ipv6_routing_hdr.ip_len = len;
ipv6_routing_hdr.ip_rtype = rtype;
ipv6_routing_hdr.ip_segments = segments;
/*
* Appened the protocol unit to the list.
*/
n = libnet_pblock_append(l, p, (uint8_t *)&ipv6_routing_hdr,
LIBNET_IPV6_ROUTING_H);
if (n == -1)
{
goto bad;
}
/* boilerplate payload sanity check / append macro */
LIBNET_DO_PAYLOAD(l, p);
/*
* Update the protocol block's meta information and return the protocol
* tag id of this pblock. This tag will be used to locate the pblock
* in order to modify the protocol header in subsequent calls.
*/
return (ptag ? ptag : libnet_pblock_update(l, p, h,
LIBNET_PBLOCK_IPV6_ROUTING_H));
bad:
libnet_pblock_delete(l, p);
return (-1);
}
libnet_ptag_t
libnet_build_ipv6_destopts(uint8_t nh, uint8_t len, const uint8_t *payload,
uint32_t payload_s, libnet_t *l, libnet_ptag_t ptag)
{
uint32_t n;
uint16_t h;
libnet_pblock_t *p;
struct libnet_ipv6_destopts_hdr ipv6_destopts_hdr;
if (l == NULL)
{
return (-1);
}
/* Important: IPv6 dest opts information is specified using the payload
* interface!
*/
n = LIBNET_IPV6_DESTOPTS_H + payload_s;
h = 0;
if (LIBNET_IPV6_DESTOPTS_H + payload_s > IP_MAXPACKET)
{
snprintf(l->err_buf, LIBNET_ERRBUF_SIZE,
"%s(): IP packet too large", __func__);
return (-1);
}
/*
* Find the existing protocol block if a ptag is specified, or create
* a new one.
*/
p = libnet_pblock_probe(l, ptag, n, LIBNET_PBLOCK_IPV6_DESTOPTS_H);
if (p == NULL)
{
return (-1);
}
memset(&ipv6_destopts_hdr, 0 , sizeof(ipv6_destopts_hdr));
ipv6_destopts_hdr.ip_nh = nh;
ipv6_destopts_hdr.ip_len = len;
/*
* Appened the protocol unit to the list.
*/
n = libnet_pblock_append(l, p, (uint8_t *)&ipv6_destopts_hdr,
LIBNET_IPV6_DESTOPTS_H);
if (n == -1)
{
goto bad;
}
/* boilerplate payload sanity check / append macro */
LIBNET_DO_PAYLOAD(l, p);
/*
* Update the protocol block's meta information and return the protocol
* tag id of this pblock. This tag will be used to locate the pblock
* in order to modify the protocol header in subsequent calls.
*/
return (ptag ? ptag : libnet_pblock_update(l, p, h,
LIBNET_PBLOCK_IPV6_DESTOPTS_H));
bad:
libnet_pblock_delete(l, p);
return (-1);
}
libnet_ptag_t
libnet_build_ipv6_hbhopts(uint8_t nh, uint8_t len, const uint8_t *payload,
uint32_t payload_s, libnet_t *l, libnet_ptag_t ptag)
{
uint32_t n;
uint16_t h;
libnet_pblock_t *p;
struct libnet_ipv6_hbhopts_hdr ipv6_hbhopts_hdr;
if (l == NULL)
{
return (-1);
}
/* Important: IPv6 hop by hop opts information is specified using the
* payload interface!
*/
n = LIBNET_IPV6_HBHOPTS_H + payload_s;
h = 0;
if (LIBNET_IPV6_HBHOPTS_H + payload_s > IP_MAXPACKET)
{
snprintf(l->err_buf, LIBNET_ERRBUF_SIZE,
"%s(): IP packet too large", __func__);
return (-1);
}
/*
* Find the existing protocol block if a ptag is specified, or create
* a new one.
*/
p = libnet_pblock_probe(l, ptag, n, LIBNET_PBLOCK_IPV6_HBHOPTS_H);
if (p == NULL)
{
return (-1);
}
memset(&ipv6_hbhopts_hdr, 0 , sizeof(ipv6_hbhopts_hdr));
ipv6_hbhopts_hdr.ip_nh = nh;
ipv6_hbhopts_hdr.ip_len = len;
/*
* Appened the protocol unit to the list.
*/
n = libnet_pblock_append(l, p, (uint8_t *)&ipv6_hbhopts_hdr,
LIBNET_IPV6_HBHOPTS_H);
if (n == -1)
{
goto bad;
}
/* boilerplate payload sanity check / append macro */
LIBNET_DO_PAYLOAD(l, p);
/*
* Update the protocol block's meta information and return the protocol
* tag id of this pblock. This tag will be used to locate the pblock
* in order to modify the protocol header in subsequent calls.
*/
return (ptag ? ptag : libnet_pblock_update(l, p, h,
LIBNET_PBLOCK_IPV6_HBHOPTS_H));
bad:
libnet_pblock_delete(l, p);
return (-1);
}
libnet_ptag_t
libnet_autobuild_ipv6(uint16_t len, uint8_t nh, struct libnet_in6_addr dst,
libnet_t *l, libnet_ptag_t ptag)
{
struct libnet_in6_addr src;
src = libnet_get_ipaddr6(l);
if (libnet_in6_is_error(src))
{
return (-1);
}
return libnet_build_ipv6(0, 0, len, nh, 64, src, dst, NULL, 0, l, ptag);
}
/**
* Local Variables:
* indent-tabs-mode: nil
* c-file-style: "stroustrup"
* End:
*/
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