net.h

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#pragma once
/*
 *  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 St, Fifth Floor, Boston, MA 02110-1301, USA
 */
 
/** Structures and functions for parsing raw network packets
 *
 * @file src/lib/util/net.h
 *
 * @author Arran Cudbard-Bell (a.cudbardb@freeradius.org)
 * @copyright 2014 Arran Cudbard-Bell (a.cudbardb@freeradius.org)
 */
RCSIDH(net_h, "$Id: 899696e4002696895ff825487cfd97a2d5fd7d67 $")
 
#ifdef __cplusplus
extern "C" {
#endif
 
#ifdef HAVE_LIBPCAP
#  include <pcap.h>
#endif
 
#include <freeradius-devel/build.h>
#include <freeradius-devel/ethernet/ethernet.h>
#include <freeradius-devel/missing.h>
#include <freeradius-devel/util/hash.h>
#include <freeradius-devel/util/misc.h>
#include <freeradius-devel/util/strerror.h>
#include <freeradius-devel/util/table.h>
 
#include <netinet/in.h>
#include <stdint.h>
#include <sys/socket.h>
 
/*
 *      If we don't have libpcap, we still need an enumeration of link layers.
 */
#ifndef HAVE_LIBPCAP
typedef enum {
        DLT_RAW,
        DLT_NULL,
        DLT_LOOP,
        DLT_EN10MB,
        DLT_LINUX_SLL,
        DLT_PFLOG
} fr_dlt;
#endif
 
/*
 *      The number of bytes in an ethernet (MAC) address.
 */
#define ETHER_ADDR_LEN  6
 
/*
 *      Length of a DEC/Intel/Xerox or 802.3 Ethernet header.
 *      Note that some compilers may pad "struct ether_header" to
 *      a multiple of 4 *bytes, for example, so "sizeof (struct
 *      ether_header)" may not give the right answer.
 *
 *      6 Byte SRC, 6 Byte DST, 2 Byte Ether type, 4 Byte CVID, 4 Byte SVID
 */
#define ETHER_HDR_LEN   22
#define IP_HDR_LEN      60
 
/*
 *      The number of bytes in a RADIUS packet header.
 */
#define RADIUS_HEADER_LENGTH    20
 
/*
 *      RADIUS packet length.
 *      RFC 2865, Section 3., subsection 'length' says:
 *      " ... and maximum length is 4096."
 */
#define MAX_RADIUS_LEN  4096
#define MIN_RADIUS_LEN  20
#define RADIUS_AUTH_VECTOR_LENGTH       16
 
 
#define IP_V(ip)        (((ip)->ip_vhl & 0xf0) >> 4)
#define IP_HL(ip)       (((ip)->ip_vhl & 0x0f) << 2)
 
#define IP_VHL(v, hl) ((v & 0x0f) << 4) | (hl & 0x0f)
 
#define I_DF            0x4000          //!< Dont fragment flag.
#define IP_MF           0x2000          //!< More fragments flag.
#define IP_OFFMASK      0x1fff          //!< Mask for fragmenting bits.
 
/*
 *      Structure of an internet header, naked of options.
 */
typedef struct CC_HINT(__packed__) {
        uint8_t         ip_vhl;         //!< Header length, version.
 
        uint8_t         ip_tos;         //!< Type of service.
        uint16_t        ip_len;         //!< Total length.
        uint16_t        ip_id;          //!< identification.
        uint16_t        ip_off;         //!< Fragment offset field.
 
        uint8_t         ip_ttl;         //!< Time To Live.
        uint8_t         ip_p;           //!< Protocol.
        uint16_t        ip_sum;         //!< Checksum.
        struct in_addr  ip_src, ip_dst; //!< Src and Dst address
} ip_header_t;
 
typedef struct CC_HINT(__packed__) {
        uint32_t        ip_vtcfl;       //!< Version, traffic class, flow label.
        uint16_t        ip_len;         //!< Payload length
 
        uint8_t         ip_next;        //!< Next header (protocol)
        uint8_t         ip_hopl;        //!< IP Hop Limit
 
        struct in6_addr ip_src, ip_dst; //!< Src and Dst address
} ip_header6_t;
 
typedef struct CC_HINT(__packed__) {
        struct in6_addr ip_src, ip_dst; //!< Src and Dst address
        uint32_t        ip_len;         //!< length
        uint32_t        ip_next;        //!< upper 24 bits must be zero
} ip_pseudo_header6_t;
 
/*
 *      UDP protocol header.
 *      Per RFC 768, September, 1981.
 */
typedef struct CC_HINT(__packed__) {
        uint16_t        src;            //!< Source port.
        uint16_t        dst;            //!< Destination port.
        uint16_t        len;            //!< UDP length.
        uint16_t        checksum;       //!< UDP checksum.
} udp_header_t;
 
extern fr_table_num_sorted_t const fr_net_ip_proto_table[];
extern size_t fr_net_ip_proto_table_len;
extern fr_table_num_sorted_t const fr_net_sock_type_table[];
extern size_t fr_net_sock_type_table_len;
extern fr_table_num_sorted_t const fr_net_af_table[];
extern size_t fr_net_af_table_len;
 
uint16_t        fr_udp_checksum(uint8_t const *data, uint16_t len, uint16_t checksum,
                                struct in_addr const src_addr, struct in_addr const dst_addr);
int             fr_udp_header_check(uint8_t const *data, uint16_t remaining, ip_header_t const *ip);
uint16_t        fr_ip_header_checksum(uint8_t const *data, uint8_t ihl);
uint16_t        fr_ip6_pesudo_header_checksum(struct in6_addr const *src, struct in6_addr const *dst, uint16_t ip_len, uint8_t ip_next);
 
#ifdef __cplusplus
}
#endif