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Diffstat (limited to 'framework/src/suricata/src/decode-udp.h')
| -rw-r--r-- | framework/src/suricata/src/decode-udp.h | 193 |
1 files changed, 193 insertions, 0 deletions
diff --git a/framework/src/suricata/src/decode-udp.h b/framework/src/suricata/src/decode-udp.h new file mode 100644 index 00000000..5636c32b --- /dev/null +++ b/framework/src/suricata/src/decode-udp.h @@ -0,0 +1,193 @@ +/* Copyright (C) 2007-2013 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 Victor Julien <victor@inliniac.net> + */ + +#ifndef __DECODE_UDP_H__ +#define __DECODE_UDP_H__ + +#define UDP_HEADER_LEN 8 + +/* XXX RAW* needs to be really 'raw', so no ntohs there */ +#define UDP_GET_RAW_LEN(udph) ntohs((udph)->uh_len) +#define UDP_GET_RAW_SRC_PORT(udph) ntohs((udph)->uh_sport) +#define UDP_GET_RAW_DST_PORT(udph) ntohs((udph)->uh_dport) + +#define UDP_GET_LEN(p) UDP_GET_RAW_LEN(p->udph) +#define UDP_GET_SRC_PORT(p) UDP_GET_RAW_SRC_PORT(p->udph) +#define UDP_GET_DST_PORT(p) UDP_GET_RAW_DST_PORT(p->udph) + +/* UDP header structure */ +typedef struct UDPHdr_ +{ + uint16_t uh_sport; /* source port */ + uint16_t uh_dport; /* destination port */ + uint16_t uh_len; /* length */ + uint16_t uh_sum; /* checksum */ +} __attribute__((__packed__)) UDPHdr; + +typedef struct UDPVars_ +{ +} UDPVars; + +#define CLEAR_UDP_PACKET(p) do { \ + (p)->udph = NULL; \ + (p)->level4_comp_csum = -1; \ +} while (0) + +void DecodeUDPV4RegisterTests(void); + +/** ------ Inline function ------ */ +static inline uint16_t UDPV4CalculateChecksum(uint16_t *, uint16_t *, uint16_t); +static inline uint16_t UDPV6CalculateChecksum(uint16_t *, uint16_t *, uint16_t); + +/** + * \brief Calculates the checksum for the UDP packet + * + * \param shdr Pointer to source address field from the IP packet. Used as a + * part of the psuedoheader for computing the checksum + * \param pkt Pointer to the start of the UDP packet + * \param hlen Total length of the UDP packet(header + payload) + * + * \retval csum Checksum for the UDP packet + */ +static inline uint16_t UDPV4CalculateChecksum(uint16_t *shdr, uint16_t *pkt, + uint16_t tlen) +{ + uint16_t pad = 0; + uint32_t csum = shdr[0]; + + csum += shdr[1] + shdr[2] + shdr[3] + htons(17) + htons(tlen); + + csum += pkt[0] + pkt[1] + pkt[2]; + + tlen -= 8; + pkt += 4; + + while (tlen >= 32) { + csum += pkt[0] + pkt[1] + pkt[2] + pkt[3] + pkt[4] + pkt[5] + pkt[6] + + pkt[7] + pkt[8] + pkt[9] + pkt[10] + pkt[11] + pkt[12] + pkt[13] + + pkt[14] + pkt[15]; + tlen -= 32; + pkt += 16; + } + + while(tlen >= 8) { + csum += pkt[0] + pkt[1] + pkt[2] + pkt[3]; + tlen -= 8; + pkt += 4; + } + + while(tlen >= 4) { + csum += pkt[0] + pkt[1]; + tlen -= 4; + pkt += 2; + } + + while (tlen > 1) { + csum += pkt[0]; + pkt += 1; + tlen -= 2; + } + + if (tlen == 1) { + *(uint8_t *)(&pad) = (*(uint8_t *)pkt); + csum += pad; + } + + csum = (csum >> 16) + (csum & 0x0000FFFF); + csum += (csum >> 16); + + uint16_t csum_u16 = (uint16_t)~csum; + if (csum_u16 == 0) + return 0xFFFF; + else + return csum_u16; +} + +/** + * \brief Calculates the checksum for the UDP packet + * + * \param shdr Pointer to source address field from the IPV6 packet. Used as a + * part of the psuedoheader for computing the checksum + * \param pkt Pointer to the start of the UDP packet + * \param tlen Total length of the UDP packet(header + payload) + * + * \retval csum Checksum for the UDP packet + */ +static inline uint16_t UDPV6CalculateChecksum(uint16_t *shdr, uint16_t *pkt, + uint16_t tlen) +{ + uint16_t pad = 0; + uint32_t csum = shdr[0]; + + csum += shdr[1] + shdr[2] + shdr[3] + shdr[4] + shdr[5] + shdr[6] + + shdr[7] + shdr[8] + shdr[9] + shdr[10] + shdr[11] + shdr[12] + + shdr[13] + shdr[14] + shdr[15] + htons(17) + htons(tlen); + + csum += pkt[0] + pkt[1] + pkt[2]; + + tlen -= 8; + pkt += 4; + + while (tlen >= 32) { + csum += pkt[0] + pkt[1] + pkt[2] + pkt[3] + pkt[4] + pkt[5] + pkt[6] + + pkt[7] + pkt[8] + pkt[9] + pkt[10] + pkt[11] + pkt[12] + pkt[13] + + pkt[14] + pkt[15]; + tlen -= 32; + pkt += 16; + } + + while(tlen >= 8) { + csum += pkt[0] + pkt[1] + pkt[2] + pkt[3]; + tlen -= 8; + pkt += 4; + } + + while(tlen >= 4) { + csum += pkt[0] + pkt[1]; + tlen -= 4; + pkt += 2; + } + + while (tlen > 1) { + csum += pkt[0]; + pkt += 1; + tlen -= 2; + } + + if (tlen == 1) { + *(uint8_t *)(&pad) = (*(uint8_t *)pkt); + csum += pad; + } + + csum = (csum >> 16) + (csum & 0x0000FFFF); + csum += (csum >> 16); + + uint16_t csum_u16 = (uint16_t)~csum; + if (csum_u16 == 0) + return 0xFFFF; + else + return csum_u16; +} + + +#endif /* __DECODE_UDP_H__ */ |