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/* Copyright (C) 2011-2012 Open Information Security Foundation
*
* You can copy, redistribute or modify this Program under the terms of
* the GNU General Public License version 2 as published by the Free
* Software Foundation.
*
* 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
* version 2 along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*/
/**
* \file
*
* \author Eric Leblond <eric@regit.org>
*
* Util functions for checskum.
*/
#include "suricata-common.h"
#include "util-checksum.h"
int ReCalculateChecksum(Packet *p)
{
if (PKT_IS_IPV4(p)) {
if (PKT_IS_TCP(p)) {
/* TCP */
p->tcph->th_sum = 0;
p->tcph->th_sum = TCPCalculateChecksum(p->ip4h->s_ip_addrs,
(uint16_t *)p->tcph, (p->payload_len + TCP_GET_HLEN(p)));
} else if (PKT_IS_UDP(p)) {
p->udph->uh_sum = 0;
p->udph->uh_sum = UDPV4CalculateChecksum(p->ip4h->s_ip_addrs,
(uint16_t *)p->udph, (p->payload_len + UDP_HEADER_LEN));
}
/* IPV4 */
p->ip4h->ip_csum = 0;
p->ip4h->ip_csum = IPV4CalculateChecksum((uint16_t *)p->ip4h,
IPV4_GET_RAW_HLEN(p->ip4h));
} else if (PKT_IS_IPV6(p)) {
/* just TCP for IPV6 */
if (PKT_IS_TCP(p)) {
p->tcph->th_sum = 0;
p->tcph->th_sum = TCPV6CalculateChecksum(p->ip6h->s_ip6_addrs,
(uint16_t *)p->tcph, (p->payload_len + TCP_GET_HLEN(p)));
} else if (PKT_IS_UDP(p)) {
p->udph->uh_sum = 0;
p->udph->uh_sum = UDPV6CalculateChecksum(p->ip6h->s_ip6_addrs,
(uint16_t *)p->udph, (p->payload_len + UDP_HEADER_LEN));
}
}
return 0;
}
/**
* \brief Check if the number of invalid checksums indicate checksum
* offloading in place.
*
* \retval 1 yes, offloading in place
* \retval 0 no, no offloading used
*/
int ChecksumAutoModeCheck(uint32_t thread_count,
unsigned int iface_count, unsigned int iface_fail)
{
if (thread_count == CHECKSUM_SAMPLE_COUNT) {
if (iface_fail != 0) {
if ((iface_count / iface_fail) < CHECKSUM_INVALID_RATIO) {
SCLogInfo("More than 1/%dth of packets have an invalid "
"checksum, assuming checksum offloading is used (%u/%u)",
CHECKSUM_INVALID_RATIO, iface_fail, iface_count);
return 1;
} else {
SCLogInfo("Less than 1/%dth of packets have an invalid "
"checksum, assuming checksum offloading is NOT used (%u/%u)",
CHECKSUM_INVALID_RATIO, iface_fail, iface_count);
}
} else {
SCLogInfo("No packets with invalid checksum, assuming checksum offloading is NOT used");
}
}
return 0;
}
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