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/*
* Copyright 2013 Google Inc.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*/
/*
* Author: ncardwell@google.com (Neal Cardwell)
*
* Implementation for module for formatting IPv4 and IPv6 packets.
*/
#include "ip_packet.h"
#include "checksum.h"
#include "ip.h"
#include "ipv6.h"
/* Fill in IPv4 header fields. */
static void set_ipv4_header(struct ipv4 *ipv4,
u16 ip_bytes, u8 tos,
u8 ttl, u8 protocol)
{
ipv4->version = 4;
ipv4->ihl = sizeof(struct ipv4) / sizeof(u32);
ipv4->tos = tos;
ipv4->tot_len = htons(ip_bytes);
ipv4->id = 0;
ipv4->frag_off = 0;
if (ttl)
ipv4->ttl = ttl;
else
ipv4->ttl = TTL_CHECK_NONE;
ipv4->protocol = protocol;
ipv4->check = 0;
ipv4->src_ip = in4addr_any;
ipv4->dst_ip = in4addr_any;
}
/* Fill in IPv6 header fields. */
static void set_ipv6_header(struct ipv6 *ipv6,
u16 ip_bytes,
u8 tos, u32 flow_label,
u8 hop_limit, u8 protocol)
{
ipv6->version = 6;
ipv6->traffic_class_hi = tos >> 4;
ipv6->traffic_class_lo = tos & 0x0f;
ipv6->flow_label_hi = (flow_label >> 16) & 0xf;
ipv6->flow_label_lo = htons(flow_label & 0xffff);
assert(ip_bytes >= sizeof(*ipv6));
ipv6->payload_len = htons(ip_bytes - sizeof(*ipv6));
ipv6->next_header = protocol;
if (hop_limit)
ipv6->hop_limit = hop_limit;
else
ipv6->hop_limit = TTL_CHECK_NONE;
ipv6->src_ip = in6addr_any;
ipv6->dst_ip = in6addr_any;
}
void set_ip_header(void *ip_header,
int address_family,
u16 ip_bytes,
u8 tos, u32 flowlabel,
u8 ttl, u8 protocol)
{
if (address_family == AF_INET)
set_ipv4_header(ip_header, ip_bytes, tos, ttl, protocol);
else if (address_family == AF_INET6)
set_ipv6_header(ip_header, ip_bytes, tos, flowlabel,
ttl, protocol);
else
assert(!"bad ip_version in config");
}
void set_packet_ip_header(struct packet *packet,
int address_family,
u16 ip_bytes,
u8 tos, u32 flowlabel,
u8 ttl, u8 protocol)
{
struct header *ip_header = NULL;
if (address_family == AF_INET) {
struct ipv4 *ipv4 = (struct ipv4 *) packet->buffer;
packet->ipv4 = ipv4;
assert(packet->ipv6 == NULL);
ip_header = packet_append_header(packet, HEADER_IPV4,
sizeof(*ipv4));
ip_header->total_bytes = ip_bytes;
set_ipv4_header(ipv4, ip_bytes, tos, ttl, protocol);
} else if (address_family == AF_INET6) {
struct ipv6 *ipv6 = (struct ipv6 *) packet->buffer;
packet->ipv6 = ipv6;
assert(packet->ipv4 == NULL);
ip_header = packet_append_header(packet, HEADER_IPV6,
sizeof(*ipv6));
ip_header->total_bytes = ip_bytes;
set_ipv6_header(ipv6, ip_bytes, tos, flowlabel, ttl, protocol);
} else {
assert(!"bad ip_version in config");
}
}
int ipv4_header_append(struct packet *packet,
const char *ip_src,
const char *ip_dst,
const u8 tos,
const u8 ttl,
char **error)
{
struct header *header = NULL;
const int ipv4_bytes = sizeof(struct ipv4);
struct ipv4 *ipv4 = NULL;
header = packet_append_header(packet, HEADER_IPV4, ipv4_bytes);
if (header == NULL) {
asprintf(error, "too many headers");
return STATUS_ERR;
}
ipv4 = header->h.ipv4;
set_ip_header(ipv4, AF_INET, 0, tos, 0, ttl, 0);
if (inet_pton(AF_INET, ip_src, &ipv4->src_ip) != 1) {
asprintf(error, "bad IPv4 src address: '%s'\n", ip_src);
return STATUS_ERR;
}
if (inet_pton(AF_INET, ip_dst, &ipv4->dst_ip) != 1) {
asprintf(error, "bad IPv4 dst address: '%s'\n", ip_dst);
return STATUS_ERR;
}
return STATUS_OK;
}
int ipv6_header_append(struct packet *packet,
const char *ip_src,
const char *ip_dst,
const u8 tos,
const u8 hop_limit,
char **error)
{
struct header *header = NULL;
const int ipv6_bytes = sizeof(struct ipv6);
struct ipv6 *ipv6 = NULL;
header = packet_append_header(packet, HEADER_IPV6, ipv6_bytes);
if (header == NULL) {
asprintf(error, "too many headers");
return STATUS_ERR;
}
ipv6 = header->h.ipv6;
set_ip_header(ipv6, AF_INET6, sizeof(struct ipv6), tos, 0, hop_limit, 0);
if (inet_pton(AF_INET6, ip_src, &ipv6->src_ip) != 1) {
asprintf(error, "bad IPv6 src address: '%s'\n", ip_src);
return STATUS_ERR;
}
if (inet_pton(AF_INET6, ip_dst, &ipv6->dst_ip) != 1) {
asprintf(error, "bad IPv6 dst address: '%s'\n", ip_dst);
return STATUS_ERR;
}
return STATUS_OK;
}
int ipv4_header_finish(struct packet *packet,
struct header *header, struct header *next_inner)
{
struct ipv4 *ipv4 = header->h.ipv4;
int ip_bytes = sizeof(struct ipv4) + next_inner->total_bytes;
ipv4->tot_len = htons(ip_bytes);
ipv4->protocol = header_type_info(next_inner->type)->ip_proto;
/* Fill in IPv4 header checksum. */
ipv4->check = 0;
ipv4->check = ipv4_checksum(ipv4, ipv4->ihl * sizeof(u32));
header->total_bytes = ip_bytes;
return STATUS_OK;
}
int ipv6_header_finish(struct packet *packet,
struct header *header, struct header *next_inner)
{
struct ipv6 *ipv6 = header->h.ipv6;
int ip_bytes = sizeof(struct ipv6) + next_inner->total_bytes;
assert(next_inner->total_bytes <= 0xffff);
ipv6->payload_len = htons(next_inner->total_bytes);
ipv6->next_header = header_type_info(next_inner->type)->ip_proto;
/* IPv6 has no header checksum. */
header->total_bytes = ip_bytes;
return STATUS_OK;
}
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