SRC/pcarp.c File Reference

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Detailed Description

Address Resolution Protocol.

2002-09 Gundolf von Bachhaus: 90% rewrite - Optional non-blocking ARP lookup & redirect handling Gateway / Route / ARP data stored & accessed sererately Module encapsulated - no global variables

Definition in file pcarp.c.

Go to the source code of this file.

Data Structures
struct	route_entry
	ROUTE (& REDIRECT) HANDLING. More...
Functions
BOOL	LAN_lookup (DWORD ip, eth_address *eth)
	Lookup host in fixed/dynamic list.
BOOL	is_on_LAN (DWORD ip)
	This should probably go in pcconfig.c.
void	arp_daemon (void)
	ARP "background" daemon.
int	_arp_list_gateways (struct gate_entry *gw, int max)
	Gateway functions.
int	ping_gateway (DWORD host, void *eth)
void	check_dead_gw (void)
BOOL	_arp_add_gateway (const char *config_string, DWORD ip)
	Add a gateway to the routing table.
void	_arp_kill_gateways (void)
	Delete all gateways.
BOOL	_arp_have_default_gw (void)
	Check if we have at least one default gateway.
__inline BOOL	arp_send (const arp_Header *arp, unsigned line)
	Low-level ARP send function.
BOOL	arp_send_request (DWORD ip)
	Send broadcast ARP request.
BOOL	_arp_reply (const void *mac_dst, DWORD src_ip, DWORD dst_ip)
	Send unicast/broadcast ARP reply.
__inline void	arp_move_entry (int to_index, int from_index)
	Move an ARP entry from from_index to to_index.
BOOL	LAN_start_lookup (DWORD ip)
	Start a host lookup on the LAN.
BOOL	LAN_lookup_pending (DWORD ip)
	Lookup host in pending list.
void	arp_check_timeouts (BOOL check_dynamic_entries)
	Check ARP entries for timeout.
__inline void	route_move_entry (int to_index, int from_index)
BOOL	route_makeNewSlot (DWORD host_ip, DWORD gate_ip)
BOOL	_arp_register (DWORD use_this_gateway_ip, DWORD for_this_host_ip)
	ICMP redirection.
BOOL	route_lookup (DWORD host_ip, eth_address *eth)
	Gets MAC of gateway needed to reach the given host.
BOOL	route_lookup_pending (DWORD host_ip)
	Returns TRUE if the lookup of the gateway (assigned to the supplied host) is still pending.
BOOL	route_start_lookup (DWORD host_ip)
	Start a route lookup.
void	route_check_timeouts (BOOL check_dynamic_entries)
	Periodic route checker.
BOOL	arp_start_lookup (DWORD ip)
	New non-blocking functions, GvB 2002-09.
BOOL	arp_lookup (DWORD ip, eth_address *eth)
	Lookup MAC-address of 'ip'.
BOOL	arp_lookup_pending (DWORD ip)
	An ARP-lookup timeout check.
BOOL	arp_lookup_fixed (DWORD ip, eth_address *eth)
	Lookup fixed MAC-address of 'ip'.
BOOL	_arp_resolve (DWORD ip, eth_address *eth)
	Blocking ARP resolve functions.
BOOL	_arp_add_cache (DWORD ip, const void *eth, BOOL expires)
	ARP cache functions.
BOOL	_arp_delete_cache (DWORD ip)
	Delete given 'ip' address from ARP-cache (dynamic or fixed).
void	arp_parse (const char *name, const char *value)
void	arp_alloc (void)
void	_arp_init (void)
	'Internal' interface to pctcp.c & others.
BOOL	_arp_handler (const arp_Header *ah, BOOL brdcast)
	Receive ARP handler.
BOOL	_arp_check_own_ip (eth_address *other_guy)
	Used by DHCP initialisation.
int	_arp_list_cache (struct arp_entry *arp, int max)
	Return contents of ARP cache.
int	_arp_check_gateways (void)
	Return number of default gateways.
void	_arp_debug_dump (void)
	Debug-dump of configured gateways, route table and ARP cache.
Variables
int	arp_timeout = 2
int	arp_alive = 300
int	arp_rexmit_to = 250
int	arp_num_cache = 64
BOOL	dead_gw_detect = FALSE
BOOL	arp_gratiotous = FALSE
int	gate_top = 0
gate_entry	gate_list [GATE_TOP_OF_CACHE]
WORD	icmp_id = 0
	Send a ping (with ttl=1) to a gateway.
WORD	icmp_seq = 0
int	arp_first_pending = ARP_TOP_PENDING
int	arp_first_free = 0
int	arp_first_dynamic = 0
arp_entry	arp_list [ARP_TOP_OF_CACHE]
int	route_first_pending = route_top_pending
int	route_first_free = 0
route_entry	route_list [route_top_of_cache]
void(*	prev_cfg_hook )(const char *, const char *)
	Parser for "\c ARP.xx" keywords in "\c WATTCP.CFG".
void(*	prev_post_hook )(void)

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Function Documentation

BOOL _arp_add_cache (  DWORD  ip, const void *  eth, BOOL  expires )

ARP cache functions. Note: 'ip' is on host order. Definition at line 1197 of file pcarp.c. References _arp_delete_cache(), arp_move_entry(), DWORD, arp_entry::ip, is_on_LAN(), my_ip_addr, and set_timeout().

BOOL _arp_add_gateway (  const char *  config_string, DWORD  ip )

Add a gateway to the routing table. The format of 'config_string' is: IP-address [, subnet] , mask]] If 'config_string' is NULL, simply add 'ip' with zero mask and subnet. Definition at line 185 of file pcarp.c. References aton(), DWORD, and gate_entry::gate_ip.

BOOL _arp_check_own_ip (  eth_address *  other_guy  )

Used by DHCP initialisation. Do an ARP resolve on our own IP address to check if someone else is replying. Return non-zero if someone replied. Note: Blocks waiting for reply or timeout. Definition at line 1550 of file pcarp.c. References _arp_resolve(), DWORD, eth_address, and my_ip_addr.

void _arp_debug_dump (  void   )

Debug-dump of configured gateways, route table and ARP cache. Redone + moved here from pcdbug.c for encapsulation reasons GvB 2002-09 Definition at line 1625 of file pcarp.c. References _inet_ntoa(), DWORD, MAC_address(), gate_entry::mask, set_timeout(), and sin_mask.

BOOL _arp_delete_cache (  DWORD  ip  )

Delete given 'ip' address from ARP-cache (dynamic or fixed). Note: 'ip' is on host order. Definition at line 1261 of file pcarp.c. References arp_move_entry(), DWORD, arp_entry::flags, and arp_entry::ip.

BOOL _arp_handler (  const arp_Header *  ah, BOOL  brdcast )

Receive ARP handler. This processes incoming 'raw' ARP packets supplied by tcp_tick(). Definition at line 1412 of file pcarp.c. References _arp_add_cache(), _arp_reply(), _eth_addr, _eth_brdcast, _eth_get_hwtype(), _eth_mac_len, _inet_ntoa(), _pkt_rxmode, arp_move_entry(), arp_Header::dstIPAddr, DWORD, eth_address, arp_entry::expiry, arp_entry::flags, arp_Header::hwAddrLen, arp_Header::hwType, arp_entry::ip, MAC_address(), my_ip_addr, arp_Header::opcode, arp_Header::protoAddrLen, arp_Header::protType, RXMODE_BROADCAST, set_timeout(), arp_Header::srcEthAddr, arp_Header::srcIPAddr, and WORD.

int _arp_list_cache (  struct arp_entry *  arp, int  max )

Return contents of ARP cache. 'max' entries are returned in 'arp[]' buffers. Only entries in-use are returned. Definition at line 1576 of file pcarp.c. References eth_address, arp_entry::expiry, arp_entry::flags, arp_entry::hardware, and arp_entry::ip.

int _arp_list_gateways (  struct gate_entry *  gw, int  max )

Gateway functions. Note: Max 'num' gateways is returned in 'gw[]' buffer. Definition at line 71 of file pcarp.c. References gate_entry::echo_pending, gate_entry::gate_ip, gate_entry::is_dead, gate_entry::mask, and gate_entry::subnet.

BOOL _arp_register (  DWORD  use_this_gateway_ip, DWORD  for_this_host_ip )

ICMP redirection. Called on ICMP-redirects. Redirects are sent from a gateway/router, telling us that a different gateway is better suited to connect to the specified host than the one we were using. Definition at line 718 of file pcarp.c. References DWORD, route_entry::gate_ip, is_on_LAN(), LAN_lookup(), and LAN_start_lookup().

BOOL _arp_reply (  const void *  mac_dst, DWORD  src_ip, DWORD  dst_ip )

Send unicast/broadcast ARP reply. 'src_ip' and 'dst_ip' on network order. Definition at line 409 of file pcarp.c. References _eth_addr, _eth_brdcast, _eth_formatpacket(), _eth_get_hwtype(), arp_send(), arp_Header::dstEthAddr, arp_Header::dstIPAddr, DWORD, arp_Header::hwAddrLen, arp_Header::hwType, arp_Header::opcode, arp_Header::protoAddrLen, arp_Header::protType, arp_Header::srcEthAddr, and arp_Header::srcIPAddr.

BOOL _arp_resolve (  DWORD  ina, eth_address *  eth )

Blocking ARP resolve functions. Doesn't return until success or time-out. Definition at line 1108 of file pcarp.c. References _eth_addr, _pktserial, arp_daemon(), DWORD, eth_address, is_on_LAN(), LAN_lookup(), LAN_lookup_pending(), LAN_start_lookup(), route_lookup(), route_lookup_pending(), route_start_lookup(), tcp_tick(), and WORD.

void arp_check_timeouts (  BOOL  check_dynamic_entries  )  [static]

Check ARP entries for timeout. This function runs through the 'pending' section of the ARP table and checks for entries that have either expired or require a re-send. The 'dynamic' entries are checked for expiry if requested. Definition at line 551 of file pcarp.c. References arp_move_entry(), arp_send_request(), chk_timeout(), arp_entry::flags, and set_timeout().

void arp_daemon (  void   )  [static]

ARP "background" daemon. Calls timeout-checks / retransmitters. We don't check the dynamic entries for a timeout on every call, once a second is plenty enough. Definition at line 1323 of file pcarp.c. References _arp_check_gateways(), arp_check_timeouts(), chk_timeout(), DWORD, route_check_timeouts(), and set_timeout().

BOOL arp_lookup (  DWORD  ip, eth_address *  eth )

Lookup MAC-address of 'ip'. Return values: TRUE  MAC for 'ip' is known. Definition at line 1029 of file pcarp.c. References _eth_addr, _pktserial, DWORD, eth_address, is_on_LAN(), LAN_lookup(), and route_lookup().

BOOL arp_lookup_fixed (  DWORD  ip, eth_address *  eth )

Lookup fixed MAC-address of 'ip'. Return values: TRUE  Supplied 'ip' has a fixed MAC entry. Definition at line 1074 of file pcarp.c. References _pktserial, DWORD, eth_address, arp_entry::ip, and is_on_LAN().

BOOL arp_lookup_pending (  DWORD  ip  )

An ARP-lookup timeout check. Return values: TRUE  The lookup is currently underway ("pending"). FALSE  The IP has either been resolved (arp_lookup() == TRUE), or the lookup has timed out, i.e. the host is unreachable. Definition at line 1061 of file pcarp.c. References DWORD, is_on_LAN(), LAN_lookup_pending(), and route_lookup_pending().

BOOL arp_start_lookup (  DWORD  ip  )

New non-blocking functions, GvB 2002-09. This is called by 'higher' routines to start an ARP request. This function is non-blocking, i.e. returns 'immediately'. Definition at line 1012 of file pcarp.c. References _pktserial, DWORD, is_on_LAN(), LAN_start_lookup(), and route_start_lookup().

BOOL LAN_start_lookup (  DWORD  ip  )  [static]

Start a host lookup on the LAN. This is called by 'higher' routines to start an ARP request. This function is non-blocking, i.e. returns 'immediately'. Definition at line 446 of file pcarp.c. References arp_send_request(), DWORD, arp_entry::ip, and set_timeout().

void route_check_timeouts (  BOOL  check_dynamic_entries  )  [static]

Periodic route checker. Run through all pending entries and check if an attempt to reach a gateway was successfull, or has timed-out. If the attempt timed-out, we try the next fitting gateway. If there are no more fitting gateways to try, the connect has failed Definition at line 893 of file pcarp.c. References gate_entry::gate_ip, is_on_LAN(), LAN_lookup(), LAN_lookup_pending(), and LAN_start_lookup().

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Variable Documentation

WORD icmp_id = 0 [static]

Send a ping (with ttl=1) to a gateway. Ref. RFC-1122. Definition at line 93 of file pcarp.c.

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