ip.h

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/*
 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#ifndef IP_H
#define IP_H

#include <netinet/ip.h>
#include <netinet/ip6.h>
#include <string.h>


/*
 * Next header codes for IPv6 extensions:
 */

#define IPV6_EXT_HOP_BY_HOP 0

#define IPV6_EXT_DESTINATION 60

#define IPV6_EXT_ROUTING 43

#define IPV6_EXT_AUTH 51


typedef enum
{
        IPV4 = 4,
        IPV6 = 6,
        IP_UNKNOWN,
} ip_version;


struct ip_packet
{
        ip_version  version;

        union
        {
                struct iphdr v4;
                struct ip6_hdr v6;
        } header;

        unsigned char *data;

        unsigned int size;
};

/* AH header */
struct ip6_ahhdr
{
        uint8_t   ip6ah_nxt; 
        uint8_t   ip6ah_len;
        uint16_t  ip6ah_reserved;  
        uint32_t  ip6ah_secur;     
        uint32_t  ip6ah_sn;      
        /* followed by Authentication Data */
};
                    

/*
 * Generic IP macros:
 */

#define IP_GET_16_SUBFIELD(field, bitmask, offset) \
        ((ntohs(field) & (bitmask)) >> (offset))

#define IP_GET_32_SUBFIELD(field, bitmask, offset) \
        ((ntohl(field) & (bitmask)) >> (offset))

#define IP_SET_16_SUBFIELD(field, bitmask, offset, value) \
        (field) = (((field) & htons(~(bitmask))) | htons(((value) << (offset)) & (bitmask)))

#define IP_SET_32_SUBFIELD(field, bitmask, offset, value) \
        (field) = (((field) & htonl(~(bitmask))) | htonl(((value) << (offset)) & (bitmask)))


/*
 * IPv4 definitions & macros:
 */

#define IPV4_DF_OFFSET  14

#define IPV4_GET_DF(ip4) \
        IP_GET_16_SUBFIELD((ip4).frag_off, IP_DF, IPV4_DF_OFFSET)

#define IPV4_SET_DF(ip4, value) \
        IP_SET_16_SUBFIELD((ip4)->frag_off, IP_DF, IPV4_DF_OFFSET, (value))


/*
 * IPv6 definitions & macros:
 */

#define IPV6_VERSION_MASK  0xf0000000

#define IPV6_VERSION_OFFSET  28

#define IPV6_TC_MASK  0x0ff00000

#define IPV6_TC_OFFSET  20

#define IPV6_FLOW_LABEL_MASK  0x000fffff

#define IPV6_GET_VERSION(ip6) \
        IP_GET_32_SUBFIELD((ip6).ip6_flow, IPV6_VERSION_MASK, IPV6_VERSION_OFFSET)

#define IPV6_SET_VERSION(ip6, value) \
        IP_SET_32_SUBFIELD((ip6)->ip6_flow, IPV6_VERSION_MASK, IPV6_VERSION_OFFSET, (value))

#define IPV6_GET_TC(ip6) \
        IP_GET_32_SUBFIELD((ip6).ip6_flow, IPV6_TC_MASK, IPV6_TC_OFFSET)

#define IPV6_SET_TC(ip6, value) \
        IP_SET_32_SUBFIELD((ip6)->ip6_flow, IPV6_TC_MASK, IPV6_TC_OFFSET, (value))

#define IPV6_GET_FLOW_LABEL(ip6) \
        IP_GET_32_SUBFIELD((ip6).ip6_flow, IPV6_FLOW_LABEL_MASK, 0)

#define IPV6_SET_FLOW_LABEL(ip6, value) \
        IP_SET_32_SUBFIELD((ip6)->ip6_flow, IPV6_FLOW_LABEL_MASK, 0, (value))

#define IPV6_ADDR_FORMAT \
        "%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x"

#define IPV6_ADDR(x) \
        (x)->s6_addr[0], (x)->s6_addr[1], (x)->s6_addr[2], (x)->s6_addr[3], \
        (x)->s6_addr[4], (x)->s6_addr[5], (x)->s6_addr[6], (x)->s6_addr[7], \
        (x)->s6_addr[8], (x)->s6_addr[9], (x)->s6_addr[10], (x)->s6_addr[11], \
        (x)->s6_addr[12], (x)->s6_addr[13], (x)->s6_addr[14], (x)->s6_addr[15]

#define IPV6_ADDR_CMP(x, y) \
        ((x)->s6_addr32[0] == (y)->s6_addr32[0] && \
         (x)->s6_addr32[1] == (y)->s6_addr32[1] && \
         (x)->s6_addr32[2] == (y)->s6_addr32[2] && \
         (x)->s6_addr32[3] == (y)->s6_addr32[3])


/*
 * Inline functions
 */

static inline uint16_t swab16(uint16_t value)
{
        return ((value & 0x00ff) << 8) | ((value & 0xff00) >> 8);
}


/*
 * Function prototypes.
 */

/* Generic functions */

int ip_create(struct ip_packet *ip, unsigned char *packet, unsigned int size);
int ip_get_inner_packet(struct ip_packet outer, struct ip_packet *inner);
void ip_new(struct ip_packet *ip, ip_version version);

unsigned char * ip_get_raw_data(struct ip_packet ip);
unsigned char *ip_get_next_header(const struct ip_packet *ip,
                                  uint8_t *type);
unsigned char *ip_get_next_layer(const struct ip_packet *ip);
unsigned char *ip_get_next_ext_header_from_ip(const struct ip_packet *ip,
                                              uint8_t *type);
unsigned char *ip_get_next_ext_header_from_ext(const unsigned char *ext,
                                               uint8_t *type);

unsigned int ip_get_totlen(struct ip_packet ip);
unsigned int ip_get_hdrlen(struct ip_packet ip);
unsigned int ip_get_plen(struct ip_packet ip);

int ip_is_fragment(struct ip_packet ip);
ip_version ip_get_version(struct ip_packet ip);
unsigned int ip_get_protocol(struct ip_packet ip);
unsigned int ext_get_protocol(unsigned char * ext);
unsigned int ip_get_tos(struct ip_packet ip);
unsigned int ip_get_ttl(struct ip_packet ip);

void ip_set_protocol(struct ip_packet *ip, uint8_t value);
void ip_set_tos(struct ip_packet *ip, uint8_t value);
void ip_set_ttl(struct ip_packet *ip, uint8_t value);
void ip_set_saddr(struct ip_packet *ip, const unsigned char *value);
void ip_set_daddr(struct ip_packet *ip, const unsigned char *value);

/* IPv4 specific functions */

const struct iphdr * ipv4_get_header(const struct ip_packet *const ip);
int ipv4_get_id(struct ip_packet ip);
int ipv4_get_id_nbo(struct ip_packet ip, unsigned int nbo);
int ipv4_get_df(struct ip_packet ip);
uint32_t ipv4_get_saddr(struct ip_packet ip);
uint32_t ipv4_get_daddr(struct ip_packet ip);

void ipv4_set_id(struct ip_packet *ip, int value);
void ipv4_set_df(struct ip_packet *ip, int value);

/* IPv6 specific functions */

const struct ip6_hdr * ipv6_get_header(const struct ip_packet *const ip);
uint32_t ipv6_get_flow_label(struct ip_packet ip);
struct in6_addr * ipv6_get_saddr(struct ip_packet *ip);
struct in6_addr * ipv6_get_daddr(struct ip_packet *ip);
void ipv6_set_flow_label(struct ip_packet *ip, uint32_t value);
unsigned short ip_get_extension_size(unsigned char *ext);
unsigned short ip_get_total_extension_size(struct ip_packet ip);

/* Private functions (do not use directly) */
int get_ip_version(const unsigned char *packet,
                   unsigned int size,
                   ip_version *version);


#endif