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[NETFILTER]: nf_conntrack: add DCCP protocol support

Browse source 
Add DCCP conntrack helper. Thanks to Gerrit Renker <gerrit@erg.abdn.ac.uk>
for review and testing.

Signed-off-by: Patrick McHardy <kaber@trash.net>
This commit is contained in:
Patrick McHardy 2008-03-20 15:15:55 +01:00
parent d63a650736
commit 2bc780499a
7 changed files with 883 additions and 0 deletions
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40
include/linux/netfilter/nf_conntrack_dccp.h Normal file
View file

@ -0,0 +1,40 @@
#ifndef _NF_CONNTRACK_DCCP_H
#define _NF_CONNTRACK_DCCP_H
/* Exposed to userspace over nfnetlink */
enum ct_dccp_states {
CT_DCCP_NONE,
CT_DCCP_REQUEST,
CT_DCCP_RESPOND,
CT_DCCP_PARTOPEN,
CT_DCCP_OPEN,
CT_DCCP_CLOSEREQ,
CT_DCCP_CLOSING,
CT_DCCP_TIMEWAIT,
CT_DCCP_IGNORE,
CT_DCCP_INVALID,
__CT_DCCP_MAX
};
#define CT_DCCP_MAX (__CT_DCCP_MAX - 1)
enum ct_dccp_roles {
CT_DCCP_ROLE_CLIENT,
CT_DCCP_ROLE_SERVER,
__CT_DCCP_ROLE_MAX
};
#define CT_DCCP_ROLE_MAX (__CT_DCCP_ROLE_MAX - 1)
#ifdef __KERNEL__
#include <net/netfilter/nf_conntrack_tuple.h>
struct nf_ct_dccp {
u_int8_t role[IP_CT_DIR_MAX];
u_int8_t state;
u_int8_t last_pkt;
u_int8_t last_dir;
u_int64_t handshake_seq;
};
#endif /* __KERNEL__ */
#endif /* _NF_CONNTRACK_DCCP_H */

8
include/linux/netfilter/nfnetlink_conntrack.h
View file

@ -80,6 +80,7 @@ enum ctattr_l4proto {
enum ctattr_protoinfo {
CTA_PROTOINFO_UNSPEC,
CTA_PROTOINFO_TCP,
CTA_PROTOINFO_DCCP,
__CTA_PROTOINFO_MAX
};
#define CTA_PROTOINFO_MAX (__CTA_PROTOINFO_MAX - 1)
@ -95,6 +96,13 @@ enum ctattr_protoinfo_tcp {
};
#define CTA_PROTOINFO_TCP_MAX (__CTA_PROTOINFO_TCP_MAX - 1)
enum ctattr_protoinfo_dccp {
CTA_PROTOINFO_DCCP_UNSPEC,
CTA_PROTOINFO_DCCP_STATE,
__CTA_PROTOINFO_DCCP_MAX,
};
#define CTA_PROTOINFO_DCCP_MAX (__CTA_PROTOINFO_DCCP_MAX - 1)
enum ctattr_counters {
CTA_COUNTERS_UNSPEC,
CTA_COUNTERS_PACKETS, /* old 64bit counters */

2
include/net/netfilter/nf_conntrack.h
View file

@ -20,6 +20,7 @@
#include <asm/atomic.h>
#include <linux/netfilter/nf_conntrack_tcp.h>
#include <linux/netfilter/nf_conntrack_dccp.h>
#include <linux/netfilter/nf_conntrack_sctp.h>
#include <linux/netfilter/nf_conntrack_proto_gre.h>
#include <net/netfilter/ipv4/nf_conntrack_icmp.h>
@ -30,6 +31,7 @@
/* per conntrack: protocol private data */
union nf_conntrack_proto {
/* insert conntrack proto private data here */
struct nf_ct_dccp dccp;
struct ip_ct_sctp sctp;
struct ip_ct_tcp tcp;
struct ip_ct_icmp icmp;

6
include/net/netfilter/nf_conntrack_tuple.h
View file

@ -39,6 +39,9 @@ union nf_conntrack_man_proto
struct {
__be16 id;
} icmp;
struct {
__be16 port;
} dccp;
struct {
__be16 port;
} sctp;
@ -77,6 +80,9 @@ struct nf_conntrack_tuple
struct {
u_int8_t type, code;
} icmp;
struct {
__be16 port;
} dccp;
struct {
__be16 port;
} sctp;

10
net/netfilter/Kconfig
View file

@ -86,6 +86,16 @@ config NF_CONNTRACK_EVENTS
If unsure, say `N'.
config NF_CT_PROTO_DCCP
tristate 'DCCP protocol connection tracking support (EXPERIMENTAL)'
depends on EXPERIMENTAL && NF_CONNTRACK
depends on NETFILTER_ADVANCED
help
With this option enabled, the layer 3 independent connection
tracking code will be able to do state tracking on DCCP connections.
If unsure, say 'N'.
config NF_CT_PROTO_GRE
tristate
depends on NF_CONNTRACK

1
net/netfilter/Makefile
View file

@ -13,6 +13,7 @@ obj-$(CONFIG_NETFILTER_NETLINK_LOG) += nfnetlink_log.o
obj-$(CONFIG_NF_CONNTRACK) += nf_conntrack.o
# SCTP protocol connection tracking
obj-$(CONFIG_NF_CT_PROTO_DCCP) += nf_conntrack_proto_dccp.o
obj-$(CONFIG_NF_CT_PROTO_GRE) += nf_conntrack_proto_gre.o
obj-$(CONFIG_NF_CT_PROTO_SCTP) += nf_conntrack_proto_sctp.o
obj-$(CONFIG_NF_CT_PROTO_UDPLITE) += nf_conntrack_proto_udplite.o

816
net/netfilter/nf_conntrack_proto_dccp.c Normal file
View file

@ -0,0 +1,816 @@
/*
* DCCP connection tracking protocol helper
*
* Copyright (c) 2005, 2006, 2008 Patrick McHardy <kaber@trash.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/sysctl.h>
#include <linux/spinlock.h>
#include <linux/skbuff.h>
#include <linux/dccp.h>
#include <linux/netfilter/nfnetlink_conntrack.h>
#include <net/netfilter/nf_conntrack.h>
#include <net/netfilter/nf_conntrack_l4proto.h>
#include <net/netfilter/nf_log.h>
static DEFINE_RWLOCK(dccp_lock);
static int nf_ct_dccp_loose __read_mostly = 1;
/* Timeouts are based on values from RFC4340:
*
* - REQUEST:
*
* 8.1.2. Client Request
*
* A client MAY give up on its DCCP-Requests after some time
* (3 minutes, for example).
*
* - RESPOND:
*
* 8.1.3. Server Response
*
* It MAY also leave the RESPOND state for CLOSED after a timeout of
* not less than 4MSL (8 minutes);
*
* - PARTOPEN:
*
* 8.1.5. Handshake Completion
*
* If the client remains in PARTOPEN for more than 4MSL (8 minutes),
* it SHOULD reset the connection with Reset Code 2, "Aborted".
*
* - OPEN:
*
* The DCCP timestamp overflows after 11.9 hours. If the connection
* stays idle this long the sequence number won't be recognized
* as valid anymore.
*
* - CLOSEREQ/CLOSING:
*
* 8.3. Termination
*
* The retransmission timer should initially be set to go off in two
* round-trip times and should back off to not less than once every
* 64 seconds ...
*
* - TIMEWAIT:
*
* 4.3. States
*
* A server or client socket remains in this state for 2MSL (4 minutes)
* after the connection has been town down, ...
*/
#define DCCP_MSL (2 * 60 * HZ)
static unsigned int dccp_timeout[CT_DCCP_MAX + 1] __read_mostly = {
[CT_DCCP_REQUEST] = 2 * DCCP_MSL,
[CT_DCCP_RESPOND] = 4 * DCCP_MSL,
[CT_DCCP_PARTOPEN] = 4 * DCCP_MSL,
[CT_DCCP_OPEN] = 12 * 3600 * HZ,
[CT_DCCP_CLOSEREQ] = 64 * HZ,
[CT_DCCP_CLOSING] = 64 * HZ,
[CT_DCCP_TIMEWAIT] = 2 * DCCP_MSL,
};
static const char * const dccp_state_names[] = {
[CT_DCCP_NONE] = "NONE",
[CT_DCCP_REQUEST] = "REQUEST",
[CT_DCCP_RESPOND] = "RESPOND",
[CT_DCCP_PARTOPEN] = "PARTOPEN",
[CT_DCCP_OPEN] = "OPEN",
[CT_DCCP_CLOSEREQ] = "CLOSEREQ",
[CT_DCCP_CLOSING] = "CLOSING",
[CT_DCCP_TIMEWAIT] = "TIMEWAIT",
[CT_DCCP_IGNORE] = "IGNORE",
[CT_DCCP_INVALID] = "INVALID",
};
#define sNO CT_DCCP_NONE
#define sRQ CT_DCCP_REQUEST
#define sRS CT_DCCP_RESPOND
#define sPO CT_DCCP_PARTOPEN
#define sOP CT_DCCP_OPEN
#define sCR CT_DCCP_CLOSEREQ
#define sCG CT_DCCP_CLOSING
#define sTW CT_DCCP_TIMEWAIT
#define sIG CT_DCCP_IGNORE
#define sIV CT_DCCP_INVALID
/*
* DCCP state transistion table
*
* The assumption is the same as for TCP tracking:
*
* We are the man in the middle. All the packets go through us but might
* get lost in transit to the destination. It is assumed that the destination
* can't receive segments we haven't seen.
*
* The following states exist:
*
* NONE: Initial state, expecting Request
* REQUEST: Request seen, waiting for Response from server
* RESPOND: Response from server seen, waiting for Ack from client
* PARTOPEN: Ack after Response seen, waiting for packet other than Response,
* Reset or Sync from server
* OPEN: Packet other than Response, Reset or Sync seen
* CLOSEREQ: CloseReq from server seen, expecting Close from client
* CLOSING: Close seen, expecting Reset
* TIMEWAIT: Reset seen
* IGNORE: Not determinable whether packet is valid
*
* Some states exist only on one side of the connection: REQUEST, RESPOND,
* PARTOPEN, CLOSEREQ. For the other side these states are equivalent to
* the one it was in before.
*
* Packets are marked as ignored (sIG) if we don't know if they're valid
* (for example a reincarnation of a connection we didn't notice is dead
* already) and the server may send back a connection closing Reset or a
* Response. They're also used for Sync/SyncAck packets, which we don't
* care about.
*/
static const u_int8_t
dccp_state_table[CT_DCCP_ROLE_MAX + 1][DCCP_PKT_SYNCACK + 1][CT_DCCP_MAX + 1] = {
[CT_DCCP_ROLE_CLIENT] = {
[DCCP_PKT_REQUEST] = {
/*
* sNO -> sRQ Regular Request
* sRQ -> sRQ Retransmitted Request or reincarnation
* sRS -> sRS Retransmitted Request (apparently Response
* got lost after we saw it) or reincarnation
* sPO -> sIG Ignore, conntrack might be out of sync
* sOP -> sIG Ignore, conntrack might be out of sync
* sCR -> sIG Ignore, conntrack might be out of sync
* sCG -> sIG Ignore, conntrack might be out of sync
* sTW -> sRQ Reincarnation
*
* sNO, sRQ, sRS, sPO. sOP, sCR, sCG, sTW, */
sRQ, sRQ, sRS, sIG, sIG, sIG, sIG, sRQ,
},
[DCCP_PKT_RESPONSE] = {
/*
* sNO -> sIV Invalid
* sRQ -> sIG Ignore, might be response to ignored Request
* sRS -> sIG Ignore, might be response to ignored Request
* sPO -> sIG Ignore, might be response to ignored Request
* sOP -> sIG Ignore, might be response to ignored Request
* sCR -> sIG Ignore, might be response to ignored Request
* sCG -> sIG Ignore, might be response to ignored Request
* sTW -> sIV Invalid, reincarnation in reverse direction
* goes through sRQ
*
* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
sIV, sIG, sIG, sIG, sIG, sIG, sIG, sIV,
},
[DCCP_PKT_ACK] = {
/*
* sNO -> sIV No connection
* sRQ -> sIV No connection
* sRS -> sPO Ack for Response, move to PARTOPEN (8.1.5.)
* sPO -> sPO Retransmitted Ack for Response, remain in PARTOPEN
* sOP -> sOP Regular ACK, remain in OPEN
* sCR -> sCR Ack in CLOSEREQ MAY be processed (8.3.)
* sCG -> sCG Ack in CLOSING MAY be processed (8.3.)
* sTW -> sIV
*
* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
sIV, sIV, sPO, sPO, sOP, sCR, sCG, sIV
},
[DCCP_PKT_DATA] = {
/*
* sNO -> sIV No connection
* sRQ -> sIV No connection
* sRS -> sIV No connection
* sPO -> sIV MUST use DataAck in PARTOPEN state (8.1.5.)
* sOP -> sOP Regular Data packet
* sCR -> sCR Data in CLOSEREQ MAY be processed (8.3.)
* sCG -> sCG Data in CLOSING MAY be processed (8.3.)
* sTW -> sIV
*
* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
sIV, sIV, sIV, sIV, sOP, sCR, sCG, sIV,
},
[DCCP_PKT_DATAACK] = {
/*
* sNO -> sIV No connection
* sRQ -> sIV No connection
* sRS -> sPO Ack for Response, move to PARTOPEN (8.1.5.)
* sPO -> sPO Remain in PARTOPEN state
* sOP -> sOP Regular DataAck packet in OPEN state
* sCR -> sCR DataAck in CLOSEREQ MAY be processed (8.3.)
* sCG -> sCG DataAck in CLOSING MAY be processed (8.3.)
* sTW -> sIV
*
* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
sIV, sIV, sPO, sPO, sOP, sCR, sCG, sIV
},
[DCCP_PKT_CLOSEREQ] = {
/*
* CLOSEREQ may only be sent by the server.
*
* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV
},
[DCCP_PKT_CLOSE] = {
/*
* sNO -> sIV No connection
* sRQ -> sIV No connection
* sRS -> sIV No connection
* sPO -> sCG Client-initiated close
* sOP -> sCG Client-initiated close
* sCR -> sCG Close in response to CloseReq (8.3.)
* sCG -> sCG Retransmit
* sTW -> sIV Late retransmit, already in TIME_WAIT
*
* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
sIV, sIV, sIV, sCG, sCG, sCG, sIV, sIV
},
[DCCP_PKT_RESET] = {
/*
* sNO -> sIV No connection
* sRQ -> sTW Sync received or timeout, SHOULD send Reset (8.1.1.)
* sRS -> sTW Response received without Request
* sPO -> sTW Timeout, SHOULD send Reset (8.1.5.)
* sOP -> sTW Connection reset
* sCR -> sTW Connection reset
* sCG -> sTW Connection reset
* sTW -> sIG Ignore (don't refresh timer)
*
* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
sIV, sTW, sTW, sTW, sTW, sTW, sTW, sIG
},
[DCCP_PKT_SYNC] = {
/*
* We currently ignore Sync packets
*
* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG,
},
[DCCP_PKT_SYNCACK] = {
/*
* We currently ignore SyncAck packets
*
* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG,
},
},
[CT_DCCP_ROLE_SERVER] = {
[DCCP_PKT_REQUEST] = {
/*
* sNO -> sIV Invalid
* sRQ -> sIG Ignore, conntrack might be out of sync
* sRS -> sIG Ignore, conntrack might be out of sync
* sPO -> sIG Ignore, conntrack might be out of sync
* sOP -> sIG Ignore, conntrack might be out of sync
* sCR -> sIG Ignore, conntrack might be out of sync
* sCG -> sIG Ignore, conntrack might be out of sync
* sTW -> sRQ Reincarnation, must reverse roles
*
* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
sIV, sIG, sIG, sIG, sIG, sIG, sIG, sRQ
},
[DCCP_PKT_RESPONSE] = {
/*
* sNO -> sIV Response without Request
* sRQ -> sRS Response to clients Request
* sRS -> sRS Retransmitted Response (8.1.3. SHOULD NOT)
* sPO -> sIG Response to an ignored Request or late retransmit
* sOP -> sIG Ignore, might be response to ignored Request
* sCR -> sIG Ignore, might be response to ignored Request
* sCG -> sIG Ignore, might be response to ignored Request
* sTW -> sIV Invalid, Request from client in sTW moves to sRQ
*
* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
sIV, sRS, sRS, sIG, sIG, sIG, sIG, sIV
},
[DCCP_PKT_ACK] = {
/*
* sNO -> sIV No connection
* sRQ -> sIV No connection
* sRS -> sIV No connection
* sPO -> sOP Enter OPEN state (8.1.5.)
* sOP -> sOP Regular Ack in OPEN state
* sCR -> sIV Waiting for Close from client
* sCG -> sCG Ack in CLOSING MAY be processed (8.3.)
* sTW -> sIV
*
* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
sIV, sIV, sIV, sOP, sOP, sIV, sCG, sIV
},
[DCCP_PKT_DATA] = {
/*
* sNO -> sIV No connection
* sRQ -> sIV No connection
* sRS -> sIV No connection
* sPO -> sOP Enter OPEN state (8.1.5.)
* sOP -> sOP Regular Data packet in OPEN state
* sCR -> sIV Waiting for Close from client
* sCG -> sCG Data in CLOSING MAY be processed (8.3.)
* sTW -> sIV
*
* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
sIV, sIV, sIV, sOP, sOP, sIV, sCG, sIV
},
[DCCP_PKT_DATAACK] = {
/*
* sNO -> sIV No connection
* sRQ -> sIV No connection
* sRS -> sIV No connection
* sPO -> sOP Enter OPEN state (8.1.5.)
* sOP -> sOP Regular DataAck in OPEN state
* sCR -> sIV Waiting for Close from client
* sCG -> sCG Data in CLOSING MAY be processed (8.3.)
* sTW -> sIV
*
* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
sIV, sIV, sIV, sOP, sOP, sIV, sCG, sIV
},
[DCCP_PKT_CLOSEREQ] = {
/*
* sNO -> sIV No connection
* sRQ -> sIV No connection
* sRS -> sIV No connection
* sPO -> sOP -> sCR Move directly to CLOSEREQ (8.1.5.)
* sOP -> sCR CloseReq in OPEN state
* sCR -> sCR Retransmit
* sCG -> sCR Simultaneous close, client sends another Close
* sTW -> sIV Already closed
*
* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
sIV, sIV, sIV, sCR, sCR, sCR, sCR, sIV
},
[DCCP_PKT_CLOSE] = {
/*
* sNO -> sIV No connection
* sRQ -> sIV No connection
* sRS -> sIV No connection
* sPO -> sOP -> sCG Move direcly to CLOSING
* sOP -> sCG Move to CLOSING
* sCR -> sIV Close after CloseReq is invalid
* sCG -> sCG Retransmit
* sTW -> sIV Already closed
*
* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
sIV, sIV, sIV, sCG, sCG, sIV, sCG, sIV
},
[DCCP_PKT_RESET] = {
/*
* sNO -> sIV No connection
* sRQ -> sTW Reset in response to Request
* sRS -> sTW Timeout, SHOULD send Reset (8.1.3.)
* sPO -> sTW Timeout, SHOULD send Reset (8.1.3.)
* sOP -> sTW
* sCR -> sTW
* sCG -> sTW
* sTW -> sIG Ignore (don't refresh timer)
*
* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW, sTW */
sIV, sTW, sTW, sTW, sTW, sTW, sTW, sTW, sIG
},
[DCCP_PKT_SYNC] = {
/*
* We currently ignore Sync packets
*
* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG,
},
[DCCP_PKT_SYNCACK] = {
/*
* We currently ignore SyncAck packets
*
* sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */
sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG,
},
},
};
static int dccp_pkt_to_tuple(const struct sk_buff *skb, unsigned int dataoff,
struct nf_conntrack_tuple *tuple)
{
struct dccp_hdr _hdr, *dh;
dh = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
if (dh == NULL)
return 0;
tuple->src.u.dccp.port = dh->dccph_sport;
tuple->dst.u.dccp.port = dh->dccph_dport;
return 1;
}
static int dccp_invert_tuple(struct nf_conntrack_tuple *inv,
const struct nf_conntrack_tuple *tuple)
{
inv->src.u.dccp.port = tuple->dst.u.dccp.port;
inv->dst.u.dccp.port = tuple->src.u.dccp.port;
return 1;
}
static int dccp_new(struct nf_conn *ct, const struct sk_buff *skb,
unsigned int dataoff)
{
int pf = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num;
struct dccp_hdr _dh, *dh;
const char *msg;
u_int8_t state;
dh = skb_header_pointer(skb, dataoff, sizeof(_dh), &dh);
BUG_ON(dh == NULL);
state = dccp_state_table[CT_DCCP_ROLE_CLIENT][dh->dccph_type][CT_DCCP_NONE];
switch (state) {
default:
if (nf_ct_dccp_loose == 0) {
msg = "nf_ct_dccp: not picking up existing connection ";
goto out_invalid;
}
case CT_DCCP_REQUEST:
break;
case CT_DCCP_INVALID:
msg = "nf_ct_dccp: invalid state transition ";
goto out_invalid;
}
ct->proto.dccp.role[IP_CT_DIR_ORIGINAL] = CT_DCCP_ROLE_CLIENT;
ct->proto.dccp.role[IP_CT_DIR_REPLY] = CT_DCCP_ROLE_SERVER;
ct->proto.dccp.state = CT_DCCP_NONE;
return 1;
out_invalid:
if (LOG_INVALID(IPPROTO_DCCP))
nf_log_packet(pf, 0, skb, NULL, NULL, NULL, msg);
return 0;
}
static u64 dccp_ack_seq(const struct dccp_hdr *dh)
{
const struct dccp_hdr_ack_bits *dhack;
dhack = (void *)dh + __dccp_basic_hdr_len(dh);
return ((u64)ntohs(dhack->dccph_ack_nr_high) << 32) +
ntohl(dhack->dccph_ack_nr_low);
}
static int dccp_packet(struct nf_conn *ct, const struct sk_buff *skb,
unsigned int dataoff, enum ip_conntrack_info ctinfo,
int pf, unsigned int hooknum)
{
enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
struct dccp_hdr _dh, *dh;
u_int8_t type, old_state, new_state;
enum ct_dccp_roles role;
dh = skb_header_pointer(skb, dataoff, sizeof(_dh), &dh);
BUG_ON(dh == NULL);
type = dh->dccph_type;
if (type == DCCP_PKT_RESET &&
!test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) {
/* Tear down connection immediately if only reply is a RESET */
if (del_timer(&ct->timeout))
ct->timeout.function((unsigned long)ct);
return NF_ACCEPT;
}
write_lock_bh(&dccp_lock);
role = ct->proto.dccp.role[dir];
old_state = ct->proto.dccp.state;
new_state = dccp_state_table[role][type][old_state];
switch (new_state) {
case CT_DCCP_REQUEST:
if (old_state == CT_DCCP_TIMEWAIT &&
role == CT_DCCP_ROLE_SERVER) {
/* Reincarnation in the reverse direction: reopen and
* reverse client/server roles. */
ct->proto.dccp.role[dir] = CT_DCCP_ROLE_CLIENT;
ct->proto.dccp.role[!dir] = CT_DCCP_ROLE_SERVER;
}
break;
case CT_DCCP_RESPOND:
if (old_state == CT_DCCP_REQUEST)
ct->proto.dccp.handshake_seq = dccp_hdr_seq(dh);
break;
case CT_DCCP_PARTOPEN:
if (old_state == CT_DCCP_RESPOND &&
type == DCCP_PKT_ACK &&
dccp_ack_seq(dh) == ct->proto.dccp.handshake_seq)
set_bit(IPS_ASSURED_BIT, &ct->status);
break;
case CT_DCCP_IGNORE:
/*
* Connection tracking might be out of sync, so we ignore
* packets that might establish a new connection and resync
* if the server responds with a valid Response.
*/
if (ct->proto.dccp.last_dir == !dir &&
ct->proto.dccp.last_pkt == DCCP_PKT_REQUEST &&
type == DCCP_PKT_RESPONSE) {
ct->proto.dccp.role[!dir] = CT_DCCP_ROLE_CLIENT;
ct->proto.dccp.role[dir] = CT_DCCP_ROLE_SERVER;
ct->proto.dccp.handshake_seq = dccp_hdr_seq(dh);
new_state = CT_DCCP_RESPOND;
break;
}
ct->proto.dccp.last_dir = dir;
ct->proto.dccp.last_pkt = type;
write_unlock_bh(&dccp_lock);
if (LOG_INVALID(IPPROTO_DCCP))
nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
"nf_ct_dccp: invalid packet ignored ");
return NF_ACCEPT;
case CT_DCCP_INVALID:
write_unlock_bh(&dccp_lock);
if (LOG_INVALID(IPPROTO_DCCP))
nf_log_packet(pf, 0, skb, NULL, NULL, NULL,
"nf_ct_dccp: invalid state transition ");
return -NF_ACCEPT;
}
ct->proto.dccp.last_dir = dir;
ct->proto.dccp.last_pkt = type;
ct->proto.dccp.state = new_state;
write_unlock_bh(&dccp_lock);
nf_ct_refresh_acct(ct, ctinfo, skb, dccp_timeout[new_state]);
return NF_ACCEPT;
}
static int dccp_error(struct sk_buff *skb, unsigned int dataoff,
enum ip_conntrack_info *ctinfo, int pf,
unsigned int hooknum)
{
struct dccp_hdr _dh, *dh;
unsigned int dccp_len = skb->len - dataoff;
unsigned int cscov;
const char *msg;
dh = skb_header_pointer(skb, dataoff, sizeof(_dh), &dh);
if (dh == NULL) {
msg = "nf_ct_dccp: short packet ";
goto out_invalid;
}
if (dh->dccph_doff * 4 < sizeof(struct dccp_hdr) ||
dh->dccph_doff * 4 > dccp_len) {
msg = "nf_ct_dccp: truncated/malformed packet ";
goto out_invalid;
}
cscov = dccp_len;
if (dh->dccph_cscov) {
cscov = (dh->dccph_cscov - 1) * 4;
if (cscov > dccp_len) {
msg = "nf_ct_dccp: bad checksum coverage ";
goto out_invalid;
}
}
if (nf_conntrack_checksum && hooknum == NF_INET_PRE_ROUTING &&
nf_checksum_partial(skb, hooknum, dataoff, cscov, IPPROTO_DCCP,
pf)) {
msg = "nf_ct_dccp: bad checksum ";
goto out_invalid;
}
if (dh->dccph_type >= DCCP_PKT_INVALID) {
msg = "nf_ct_dccp: reserved packet type ";
goto out_invalid;
}
return NF_ACCEPT;
out_invalid:
if (LOG_INVALID(IPPROTO_DCCP))
nf_log_packet(pf, 0, skb, NULL, NULL, NULL, msg);
return -NF_ACCEPT;
}
static int dccp_print_tuple(struct seq_file *s,
const struct nf_conntrack_tuple *tuple)
{
return seq_printf(s, "sport=%hu dport=%hu ",
ntohs(tuple->src.u.dccp.port),
ntohs(tuple->dst.u.dccp.port));
}
static int dccp_print_conntrack(struct seq_file *s, const struct nf_conn *ct)
{
return seq_printf(s, "%s ", dccp_state_names[ct->proto.dccp.state]);
}
#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
static int dccp_to_nlattr(struct sk_buff *skb, struct nlattr *nla,
const struct nf_conn *ct)
{
struct nlattr *nest_parms;
read_lock_bh(&dccp_lock);
nest_parms = nla_nest_start(skb, CTA_PROTOINFO_DCCP | NLA_F_NESTED);
if (!nest_parms)
goto nla_put_failure;
NLA_PUT_U8(skb, CTA_PROTOINFO_DCCP_STATE, ct->proto.dccp.state);
nla_nest_end(skb, nest_parms);
read_unlock_bh(&dccp_lock);
return 0;
nla_put_failure:
read_unlock_bh(&dccp_lock);
return -1;
}
static const struct nla_policy dccp_nla_policy[CTA_PROTOINFO_DCCP_MAX + 1] = {
[CTA_PROTOINFO_DCCP_STATE] = { .type = NLA_U8 },
};
static int nlattr_to_dccp(struct nlattr *cda[], struct nf_conn *ct)
{
struct nlattr *attr = cda[CTA_PROTOINFO_DCCP];
struct nlattr *tb[CTA_PROTOINFO_DCCP_MAX + 1];
int err;
if (!attr)
return 0;
err = nla_parse_nested(tb, CTA_PROTOINFO_DCCP_MAX, attr,
dccp_nla_policy);
if (err < 0)
return err;
if (!tb[CTA_PROTOINFO_DCCP_STATE] ||
nla_get_u8(tb[CTA_PROTOINFO_DCCP_STATE]) >= CT_DCCP_IGNORE)
return -EINVAL;
write_lock_bh(&dccp_lock);
ct->proto.dccp.state = nla_get_u8(tb[CTA_PROTOINFO_DCCP_STATE]);
write_unlock_bh(&dccp_lock);
return 0;
}
#endif
#ifdef CONFIG_SYSCTL
static unsigned int dccp_sysctl_table_users;
static struct ctl_table_header *dccp_sysctl_header;
static ctl_table dccp_sysctl_table[] = {
{
.ctl_name = CTL_UNNUMBERED,
.procname = "nf_conntrack_dccp_timeout_request",
.data = &dccp_timeout[CT_DCCP_REQUEST],
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec_jiffies,
},
{
.ctl_name = CTL_UNNUMBERED,
.procname = "nf_conntrack_dccp_timeout_respond",
.data = &dccp_timeout[CT_DCCP_RESPOND],
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec_jiffies,
},
{
.ctl_name = CTL_UNNUMBERED,
.procname = "nf_conntrack_dccp_timeout_partopen",
.data = &dccp_timeout[CT_DCCP_PARTOPEN],
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec_jiffies,
},
{
.ctl_name = CTL_UNNUMBERED,
.procname = "nf_conntrack_dccp_timeout_open",
.data = &dccp_timeout[CT_DCCP_OPEN],
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec_jiffies,
},
{
.ctl_name = CTL_UNNUMBERED,
.procname = "nf_conntrack_dccp_timeout_closereq",
.data = &dccp_timeout[CT_DCCP_CLOSEREQ],
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec_jiffies,
},
{
.ctl_name = CTL_UNNUMBERED,
.procname = "nf_conntrack_dccp_timeout_closing",
.data = &dccp_timeout[CT_DCCP_CLOSING],
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec_jiffies,
},
{
.ctl_name = CTL_UNNUMBERED,
.procname = "nf_conntrack_dccp_timeout_timewait",
.data = &dccp_timeout[CT_DCCP_TIMEWAIT],
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec_jiffies,
},
{
.ctl_name = CTL_UNNUMBERED,
.procname = "nf_conntrack_dccp_loose",
.data = &nf_ct_dccp_loose,
.maxlen = sizeof(nf_ct_dccp_loose),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{
.ctl_name = 0,
}
};
#endif /* CONFIG_SYSCTL */
static struct nf_conntrack_l4proto dccp_proto4 __read_mostly = {
.l3proto = AF_INET,
.l4proto = IPPROTO_DCCP,
.name = "dccp",
.pkt_to_tuple = dccp_pkt_to_tuple,
.invert_tuple = dccp_invert_tuple,
.new = dccp_new,
.packet = dccp_packet,
.error = dccp_error,
.print_tuple = dccp_print_tuple,
.print_conntrack = dccp_print_conntrack,
#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
.to_nlattr = dccp_to_nlattr,
.from_nlattr = nlattr_to_dccp,
.tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
.nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
.nla_policy = nf_ct_port_nla_policy,
#endif
#ifdef CONFIG_SYSCTL
.ctl_table_users = &dccp_sysctl_table_users,
.ctl_table_header = &dccp_sysctl_header,
.ctl_table = dccp_sysctl_table,
#endif
};
static struct nf_conntrack_l4proto dccp_proto6 __read_mostly = {
.l3proto = AF_INET6,
.l4proto = IPPROTO_DCCP,
.name = "dccp",
.pkt_to_tuple = dccp_pkt_to_tuple,
.invert_tuple = dccp_invert_tuple,
.new = dccp_new,
.packet = dccp_packet,
.error = dccp_error,
.print_tuple = dccp_print_tuple,
.print_conntrack = dccp_print_conntrack,
#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
.to_nlattr = dccp_to_nlattr,
.from_nlattr = nlattr_to_dccp,
.tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
.nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
.nla_policy = nf_ct_port_nla_policy,
#endif
#ifdef CONFIG_SYSCTL
.ctl_table_users = &dccp_sysctl_table_users,
.ctl_table_header = &dccp_sysctl_header,
.ctl_table = dccp_sysctl_table,
#endif
};
static int __init nf_conntrack_proto_dccp_init(void)
{
int err;
err = nf_conntrack_l4proto_register(&dccp_proto4);
if (err < 0)
goto err1;
err = nf_conntrack_l4proto_register(&dccp_proto6);
if (err < 0)
goto err2;
return 0;
err2:
nf_conntrack_l4proto_unregister(&dccp_proto4);
err1:
return err;
}
static void __exit nf_conntrack_proto_dccp_fini(void)
{
nf_conntrack_l4proto_unregister(&dccp_proto6);
nf_conntrack_l4proto_unregister(&dccp_proto4);
}
module_init(nf_conntrack_proto_dccp_init);
module_exit(nf_conntrack_proto_dccp_fini);
MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
MODULE_DESCRIPTION("DCCP connection tracking protocol helper");
MODULE_LICENSE("GPL");