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/**
* @file packets.h
* @brief helpers to send Teredo packets
*/
/***********************************************************************
* Copyright © 2004-2007 Rémi Denis-Courmont. *
* This program is free software; you can redistribute and/or modify *
* it under the terms of the GNU General Public License as published *
* by the Free Software Foundation; 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, you can get it from: *
* http://www.gnu.org/copyleft/gpl.html *
***********************************************************************/
#ifndef LIBTEREDO_TEREDO_PACKETS_H
# define LIBTEREDO_TEREDO_PACKETS_H
struct in6_addr;
struct ip6_hdr;
struct icmp6_hdr;
# ifdef __cplusplus
extern "C" {
#endif
/**
* Checks that the packet is an ICMPv6 Echo reply and authenticates it.
*
* @return 0 if that is the case, -1 otherwise.
*/
int CheckPing (const teredo_packet *packet);
int CheckBubble (const teredo_packet *packet);
/**
* Returns true if the packet whose header is passed as a parameter looks
* like a Teredo bubble.
*/
static inline bool IsBubble (const struct ip6_hdr *hdr)
{
return (hdr->ip6_plen == 0) && (hdr->ip6_nxt == IPPROTO_NONE);
}
/**
* Sends a Teredo Bubble.
*
* @param dst Teredo destination address.
* @param indirect determines whether the bubble is sent to the server (true)
* or the client (if indirect is false) - as determined from dst.
*
* @return 0 on success, -1 on error.
*/
int SendBubbleFromDst (int fd, const struct in6_addr *dst, bool indirect);
/**
* Sends a Teredo Bubble.
*
* @param ip destination IPv4
* @param port destination UDP port
* @param src pointer to source IPv6 address
* @param dst pointer to destination IPv6 address
*
* @return 0 on success, -1 on error.
*/
int teredo_send_bubble (int fd, uint32_t ip, uint16_t port,
const struct in6_addr *src,
const struct in6_addr *dst);
static inline int teredo_reply_bubble (int fd, uint32_t ip, uint16_t port,
const struct ip6_hdr *req)
{
return teredo_send_bubble (fd, ip, port, &req->ip6_dst, &req->ip6_src);
}
/**
* Sends a router solication with an Authentication header.
*
* @param fd socket through which the RS will be sent
* @param server_ip server IPv4 address toward which the solicitation should
* be encapsulated (network byte order)
* @param nonce pointer to the 8-bytes authentication nonce
* @param cone whether to send a Teredo “cone” solicitation
*
* @return 0 on success, -1 on error.
*/
int teredo_send_rs (int fd, uint32_t server_ip,
const unsigned char *nonce, bool cone);
/**
* Validates a router advertisement from the Teredo server.
* The RA must be of type cone if and only if cone is true.
* Prefix, flags, mapped port and IP are returned through newaddr.
* If there is a MTU option in the packet, the specified MTU value will
* be returned at mtu. If not, the value pointed to by mtu will not be
* modified.
*
* Assumption:
* The IPv6 header is valid (ie. version 6, plen matches packet's length, and
* the full packet is at least 40 bytes long).
*
* @param packet Teredo packet to be checked
* @param newaddr upon succesful return, the inferred Teredo client address
* (_not_ including any randomized flags).
* @param cone whether the RA should be a reply to “cone” RS
* @param mtu [out] MTU parameter found in the RA, not modified if the RA
* had no MTU option. Undefined on error.
*
* @return 0 on success, -1 on error.
*/
int teredo_parse_ra (const teredo_packet *restrict packet,
union teredo_addr *restrict newaddr,
bool cone, uint16_t *restrict mtu);
/**
* Sends an ICMPv6 Echo request toward an IPv6 node through the Teredo server.
*/
int SendPing (int fd, const union teredo_addr *src,
const struct in6_addr *dst);
/**
* Builds an ICMPv6 error message with specified type and code from an IPv6
* packet. The output buffer must be at least 1240 bytes long and have
* adequate IPv6 packet alignment. The ICMPv6 checksum is not set as they are
* not enough information for its computation.
*
* @param out output buffer
* @param type ICMPv6 error type
* @param code ICMPv6 error code
* @param in original IPv6 packet
* @param inlen original IPv6 packet length (including IPv6 header)
*
* @return the actual size of the generated error message, or zero if no
* ICMPv6 packet should be generated. Never fails.
*/
int BuildICMPv6Error (struct icmp6_hdr *restrict out,
uint8_t type, uint8_t code,
const struct ip6_hdr *restrict in, size_t inlen);
# if 0
/**
* Builds an ICMPv6/IPv6 error message with specified type and code from an
* IPv6 packet. The output buffer must be at least 1280 bytes long and have
* adequate IPv6 packet alignment.
*
* @param out output buffer
* @param type ICMPv6 error type
* @param code ICMPv6 error code
* @param src source IPv6 address for ICMPv6 message
* @param in original IPv6 packet
* @param len original IPv6 packet length (including IPv6 header)
*
* @return the actual size of the generated error message, or zero if no
* ICMPv6/IPv6 packet should be sent. Never fails.
*/
int BuildIPv6Error (struct ip6_hdr *out, const struct in6_addr *src,
uint8_t type, uint8_t code, const void *in, uint16_t len);
#endif
# ifdef __cplusplus
}
#endif
#endif
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