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remarkable-linux/net/netfilter/nf_conntrack_proto_dccp.c
David S. Miller a01aa920b8 Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf-next 
Pablo Neira Ayuso says:

====================
Netfilter/IPVS updates for net-next

The following patchset contains Netfilter updates for your net-next
tree. A large bunch of code cleanups, simplify the conntrack extension
codebase, get rid of the fake conntrack object, speed up netns by
selective synchronize_net() calls. More specifically, they are:

1) Check for ct->status bit instead of using nfct_nat() from IPVS and
   Netfilter codebase, patch from Florian Westphal.

2) Use kcalloc() wherever possible in the IPVS code, from Varsha Rao.

3) Simplify FTP IPVS helper module registration path, from Arushi Singhal.

4) Introduce nft_is_base_chain() helper function.

5) Enforce expectation limit from userspace conntrack helper,
   from Gao Feng.

6) Add nf_ct_remove_expect() helper function, from Gao Feng.

7) NAT mangle helper function return boolean, from Gao Feng.

8) ctnetlink_alloc_expect() should only work for conntrack with
   helpers, from Gao Feng.

9) Add nfnl_msg_type() helper function to nfnetlink to build the
   netlink message type.

10) Get rid of unnecessary cast on void, from simran singhal.

11) Use seq_puts()/seq_putc() instead of seq_printf() where possible,
    also from simran singhal.

12) Use list_prev_entry() from nf_tables, from simran signhal.

13) Remove unnecessary & on pointer function in the Netfilter and IPVS
    code.

14) Remove obsolete comment on set of rules per CPU in ip6_tables,
    no longer true. From Arushi Singhal.

15) Remove duplicated nf_conntrack_l4proto_udplite4, from Gao Feng.

16) Remove unnecessary nested rcu_read_lock() in
    __nf_nat_decode_session(). Code running from hooks are already
    guaranteed to run under RCU read side.

17) Remove deadcode in nf_tables_getobj(), from Aaron Conole.

18) Remove double assignment in nf_ct_l4proto_pernet_unregister_one(),
    also from Aaron.

19) Get rid of unsed __ip_set_get_netlink(), from Aaron Conole.

20) Don't propagate NF_DROP error to userspace via ctnetlink in
    __nf_nat_alloc_null_binding() function, from Gao Feng.

21) Revisit nf_ct_deliver_cached_events() to remove unnecessary checks,
    from Gao Feng.

22) Kill the fake untracked conntrack objects, use ctinfo instead to
    annotate a conntrack object is untracked, from Florian Westphal.

23) Remove nf_ct_is_untracked(), now obsolete since we have no
    conntrack template anymore, from Florian.

24) Add event mask support to nft_ct, also from Florian.

25) Move nf_conn_help structure to
    include/net/netfilter/nf_conntrack_helper.h.

26) Add a fixed 32 bytes scratchpad area for conntrack helpers.
    Thus, we don't deal with variable conntrack extensions anymore.
    Make sure userspace conntrack helper doesn't go over that size.
    Remove variable size ct extension infrastructure now this code
    got no more clients. From Florian Westphal.

27) Restore offset and length of nf_ct_ext structure to 8 bytes now
    that wraparound is not possible any longer, also from Florian.

28) Allow to get rid of unassured flows under stress in conntrack,
    this applies to DCCP, SCTP and TCP protocols, from Florian.

29) Shrink size of nf_conntrack_ecache structure, from Florian.

30) Use TCP_MAX_WSCALE instead of hardcoded 14 in TCP tracker,
    from Gao Feng.

31) Register SYNPROXY hooks on demand, from Florian Westphal.

32) Use pernet hook whenever possible, instead of global hook
    registration, from Florian Westphal.

33) Pass hook structure to ebt_register_table() to consolidate some
    infrastructure code, from Florian Westphal.

34) Use consume_skb() and return NF_STOLEN, instead of NF_DROP in the
    SYNPROXY code, to make sure device stats are not fooled, patch
    from Gao Feng.

35) Remove NF_CT_EXT_F_PREALLOC this kills quite some code that we
    don't need anymore if we just select a fixed size instead of
    expensive runtime time calculation of this. From Florian.

36) Constify nf_ct_extend_register() and nf_ct_extend_unregister(),
    from Florian.

37) Simplify nf_ct_ext_add(), this kills nf_ct_ext_create(), from
    Florian.

38) Attach NAT extension on-demand from masquerade and pptp helper
    path, from Florian.

39) Get rid of useless ip_vs_set_state_timeout(), from Aaron Conole.

40) Speed up netns by selective calls of synchronize_net(), from
    Florian Westphal.

41) Silence stack size warning gcc in 32-bit arch in snmp helper,
    from Florian.

42) Inconditionally call nf_ct_ext_destroy(), even if we have no
    extensions, to deal with the NF_NAT_MANIP_SRC case. Patch from
    Liping Zhang.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-01 10:47:53 -04:00

944 lines
27 KiB
C
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/*
* 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/init.h>
#include <linux/sysctl.h>
#include <linux/spinlock.h>
#include <linux/skbuff.h>
#include <linux/dccp.h>
#include <linux/slab.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>
#include <linux/netfilter/nfnetlink_conntrack.h>
#include <net/netfilter/nf_conntrack.h>
#include <net/netfilter/nf_conntrack_l4proto.h>
#include <net/netfilter/nf_conntrack_ecache.h>
#include <net/netfilter/nf_log.h>
/* 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 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 transition 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 inline struct nf_dccp_net *dccp_pernet(struct net *net)
{
return &net->ct.nf_ct_proto.dccp;
}
static bool dccp_pkt_to_tuple(const struct sk_buff *skb, unsigned int dataoff,
struct net *net, struct nf_conntrack_tuple *tuple)
{
struct dccp_hdr _hdr, *dh;
/* Actually only need first 4 bytes to get ports. */
dh = skb_header_pointer(skb, dataoff, 4, &_hdr);
if (dh == NULL)
return false;
tuple->src.u.dccp.port = dh->dccph_sport;
tuple->dst.u.dccp.port = dh->dccph_dport;
return true;
}
static bool 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 true;
}
static bool dccp_new(struct nf_conn *ct, const struct sk_buff *skb,
unsigned int dataoff, unsigned int *timeouts)
{
struct net *net = nf_ct_net(ct);
struct nf_dccp_net *dn;
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:
dn = dccp_pernet(net);
if (dn->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;
ct->proto.dccp.last_pkt = DCCP_PKT_REQUEST;
ct->proto.dccp.last_dir = IP_CT_DIR_ORIGINAL;
ct->proto.dccp.handshake_seq = 0;
return true;
out_invalid:
if (LOG_INVALID(net, IPPROTO_DCCP))
nf_log_packet(net, nf_ct_l3num(ct), 0, skb, NULL, NULL,
NULL, "%s", msg);
return false;
}
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 unsigned int *dccp_get_timeouts(struct net *net)
{
return dccp_pernet(net)->dccp_timeout;
}
static int dccp_packet(struct nf_conn *ct, const struct sk_buff *skb,
unsigned int dataoff, enum ip_conntrack_info ctinfo,
u_int8_t pf, unsigned int hooknum,
unsigned int *timeouts)
{
struct net *net = nf_ct_net(ct);
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 */
nf_ct_kill_acct(ct, ctinfo, skb);
return NF_ACCEPT;
}
spin_lock_bh(&ct->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;
spin_unlock_bh(&ct->lock);
if (LOG_INVALID(net, IPPROTO_DCCP))
nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL,
"nf_ct_dccp: invalid packet ignored ");
return NF_ACCEPT;
case CT_DCCP_INVALID:
spin_unlock_bh(&ct->lock);
if (LOG_INVALID(net, IPPROTO_DCCP))
nf_log_packet(net, 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;
spin_unlock_bh(&ct->lock);
if (new_state != old_state)
nf_conntrack_event_cache(IPCT_PROTOINFO, ct);
nf_ct_refresh_acct(ct, ctinfo, skb, timeouts[new_state]);
return NF_ACCEPT;
}
static int dccp_error(struct net *net, struct nf_conn *tmpl,
struct sk_buff *skb, unsigned int dataoff,
u_int8_t 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 (net->ct.sysctl_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(net, IPPROTO_DCCP))
nf_log_packet(net, pf, 0, skb, NULL, NULL, NULL, "%s", msg);
return -NF_ACCEPT;
}
static bool dccp_can_early_drop(const struct nf_conn *ct)
{
switch (ct->proto.dccp.state) {
case CT_DCCP_CLOSEREQ:
case CT_DCCP_CLOSING:
case CT_DCCP_TIMEWAIT:
return true;
default:
break;
}
return false;
}
static void dccp_print_tuple(struct seq_file *s,
const struct nf_conntrack_tuple *tuple)
{
seq_printf(s, "sport=%hu dport=%hu ",
ntohs(tuple->src.u.dccp.port),
ntohs(tuple->dst.u.dccp.port));
}
static void dccp_print_conntrack(struct seq_file *s, struct nf_conn *ct)
{
seq_printf(s, "%s ", dccp_state_names[ct->proto.dccp.state]);
}
#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
static int dccp_to_nlattr(struct sk_buff *skb, struct nlattr *nla,
struct nf_conn *ct)
{
struct nlattr *nest_parms;
spin_lock_bh(&ct->lock);
nest_parms = nla_nest_start(skb, CTA_PROTOINFO_DCCP | NLA_F_NESTED);
if (!nest_parms)
goto nla_put_failure;
if (nla_put_u8(skb, CTA_PROTOINFO_DCCP_STATE, ct->proto.dccp.state) ||
nla_put_u8(skb, CTA_PROTOINFO_DCCP_ROLE,
ct->proto.dccp.role[IP_CT_DIR_ORIGINAL]) ||
nla_put_be64(skb, CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ,
cpu_to_be64(ct->proto.dccp.handshake_seq),
CTA_PROTOINFO_DCCP_PAD))
goto nla_put_failure;
nla_nest_end(skb, nest_parms);
spin_unlock_bh(&ct->lock);
return 0;
nla_put_failure:
spin_unlock_bh(&ct->lock);
return -1;
}
static const struct nla_policy dccp_nla_policy[CTA_PROTOINFO_DCCP_MAX + 1] = {
[CTA_PROTOINFO_DCCP_STATE] = { .type = NLA_U8 },
[CTA_PROTOINFO_DCCP_ROLE] = { .type = NLA_U8 },
[CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ] = { .type = NLA_U64 },
[CTA_PROTOINFO_DCCP_PAD] = { .type = NLA_UNSPEC },
};
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, NULL);
if (err < 0)
return err;
if (!tb[CTA_PROTOINFO_DCCP_STATE] ||
!tb[CTA_PROTOINFO_DCCP_ROLE] ||
nla_get_u8(tb[CTA_PROTOINFO_DCCP_ROLE]) > CT_DCCP_ROLE_MAX ||
nla_get_u8(tb[CTA_PROTOINFO_DCCP_STATE]) >= CT_DCCP_IGNORE) {
return -EINVAL;
}
spin_lock_bh(&ct->lock);
ct->proto.dccp.state = nla_get_u8(tb[CTA_PROTOINFO_DCCP_STATE]);
if (nla_get_u8(tb[CTA_PROTOINFO_DCCP_ROLE]) == CT_DCCP_ROLE_CLIENT) {
ct->proto.dccp.role[IP_CT_DIR_ORIGINAL] = CT_DCCP_ROLE_CLIENT;
ct->proto.dccp.role[IP_CT_DIR_REPLY] = CT_DCCP_ROLE_SERVER;
} else {
ct->proto.dccp.role[IP_CT_DIR_ORIGINAL] = CT_DCCP_ROLE_SERVER;
ct->proto.dccp.role[IP_CT_DIR_REPLY] = CT_DCCP_ROLE_CLIENT;
}
if (tb[CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ]) {
ct->proto.dccp.handshake_seq =
be64_to_cpu(nla_get_be64(tb[CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ]));
}
spin_unlock_bh(&ct->lock);
return 0;
}
static int dccp_nlattr_size(void)
{
return nla_total_size(0) /* CTA_PROTOINFO_DCCP */
+ nla_policy_len(dccp_nla_policy, CTA_PROTOINFO_DCCP_MAX + 1);
}
#endif
#if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nfnetlink_cttimeout.h>
static int dccp_timeout_nlattr_to_obj(struct nlattr *tb[],
struct net *net, void *data)
{
struct nf_dccp_net *dn = dccp_pernet(net);
unsigned int *timeouts = data;
int i;
/* set default DCCP timeouts. */
for (i=0; i<CT_DCCP_MAX; i++)
timeouts[i] = dn->dccp_timeout[i];
/* there's a 1:1 mapping between attributes and protocol states. */
for (i=CTA_TIMEOUT_DCCP_UNSPEC+1; i<CTA_TIMEOUT_DCCP_MAX+1; i++) {
if (tb[i]) {
timeouts[i] = ntohl(nla_get_be32(tb[i])) * HZ;
}
}
return 0;
}
static int
dccp_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
{
const unsigned int *timeouts = data;
int i;
for (i=CTA_TIMEOUT_DCCP_UNSPEC+1; i<CTA_TIMEOUT_DCCP_MAX+1; i++) {
if (nla_put_be32(skb, i, htonl(timeouts[i] / HZ)))
goto nla_put_failure;
}
return 0;
nla_put_failure:
return -ENOSPC;
}
static const struct nla_policy
dccp_timeout_nla_policy[CTA_TIMEOUT_DCCP_MAX+1] = {
[CTA_TIMEOUT_DCCP_REQUEST] = { .type = NLA_U32 },
[CTA_TIMEOUT_DCCP_RESPOND] = { .type = NLA_U32 },
[CTA_TIMEOUT_DCCP_PARTOPEN] = { .type = NLA_U32 },
[CTA_TIMEOUT_DCCP_OPEN] = { .type = NLA_U32 },
[CTA_TIMEOUT_DCCP_CLOSEREQ] = { .type = NLA_U32 },
[CTA_TIMEOUT_DCCP_CLOSING] = { .type = NLA_U32 },
[CTA_TIMEOUT_DCCP_TIMEWAIT] = { .type = NLA_U32 },
};
#endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
#ifdef CONFIG_SYSCTL
/* template, data assigned later */
static struct ctl_table dccp_sysctl_table[] = {
{
.procname = "nf_conntrack_dccp_timeout_request",
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec_jiffies,
},
{
.procname = "nf_conntrack_dccp_timeout_respond",
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec_jiffies,
},
{
.procname = "nf_conntrack_dccp_timeout_partopen",
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec_jiffies,
},
{
.procname = "nf_conntrack_dccp_timeout_open",
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec_jiffies,
},
{
.procname = "nf_conntrack_dccp_timeout_closereq",
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec_jiffies,
},
{
.procname = "nf_conntrack_dccp_timeout_closing",
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec_jiffies,
},
{
.procname = "nf_conntrack_dccp_timeout_timewait",
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec_jiffies,
},
{
.procname = "nf_conntrack_dccp_loose",
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{ }
};
#endif /* CONFIG_SYSCTL */
static int dccp_kmemdup_sysctl_table(struct net *net, struct nf_proto_net *pn,
struct nf_dccp_net *dn)
{
#ifdef CONFIG_SYSCTL
if (pn->ctl_table)
return 0;
pn->ctl_table = kmemdup(dccp_sysctl_table,
sizeof(dccp_sysctl_table),
GFP_KERNEL);
if (!pn->ctl_table)
return -ENOMEM;
pn->ctl_table[0].data = &dn->dccp_timeout[CT_DCCP_REQUEST];
pn->ctl_table[1].data = &dn->dccp_timeout[CT_DCCP_RESPOND];
pn->ctl_table[2].data = &dn->dccp_timeout[CT_DCCP_PARTOPEN];
pn->ctl_table[3].data = &dn->dccp_timeout[CT_DCCP_OPEN];
pn->ctl_table[4].data = &dn->dccp_timeout[CT_DCCP_CLOSEREQ];
pn->ctl_table[5].data = &dn->dccp_timeout[CT_DCCP_CLOSING];
pn->ctl_table[6].data = &dn->dccp_timeout[CT_DCCP_TIMEWAIT];
pn->ctl_table[7].data = &dn->dccp_loose;
/* Don't export sysctls to unprivileged users */
if (net->user_ns != &init_user_ns)
pn->ctl_table[0].procname = NULL;
#endif
return 0;
}
static int dccp_init_net(struct net *net, u_int16_t proto)
{
struct nf_dccp_net *dn = dccp_pernet(net);
struct nf_proto_net *pn = &dn->pn;
if (!pn->users) {
/* default values */
dn->dccp_loose = 1;
dn->dccp_timeout[CT_DCCP_REQUEST] = 2 * DCCP_MSL;
dn->dccp_timeout[CT_DCCP_RESPOND] = 4 * DCCP_MSL;
dn->dccp_timeout[CT_DCCP_PARTOPEN] = 4 * DCCP_MSL;
dn->dccp_timeout[CT_DCCP_OPEN] = 12 * 3600 * HZ;
dn->dccp_timeout[CT_DCCP_CLOSEREQ] = 64 * HZ;
dn->dccp_timeout[CT_DCCP_CLOSING] = 64 * HZ;
dn->dccp_timeout[CT_DCCP_TIMEWAIT] = 2 * DCCP_MSL;
}
return dccp_kmemdup_sysctl_table(net, pn, dn);
}
struct nf_conntrack_l4proto nf_conntrack_l4proto_dccp4 __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,
.get_timeouts = dccp_get_timeouts,
.error = dccp_error,
.can_early_drop = dccp_can_early_drop,
.print_tuple = dccp_print_tuple,
.print_conntrack = dccp_print_conntrack,
#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
.to_nlattr = dccp_to_nlattr,
.nlattr_size = dccp_nlattr_size,
.from_nlattr = nlattr_to_dccp,
.tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
.nlattr_tuple_size = nf_ct_port_nlattr_tuple_size,
.nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
.nla_policy = nf_ct_port_nla_policy,
#endif
#if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
.ctnl_timeout = {
.nlattr_to_obj = dccp_timeout_nlattr_to_obj,
.obj_to_nlattr = dccp_timeout_obj_to_nlattr,
.nlattr_max = CTA_TIMEOUT_DCCP_MAX,
.obj_size = sizeof(unsigned int) * CT_DCCP_MAX,
.nla_policy = dccp_timeout_nla_policy,
},
#endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
.init_net = dccp_init_net,
};
EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_dccp4);
struct nf_conntrack_l4proto nf_conntrack_l4proto_dccp6 __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,
.get_timeouts = dccp_get_timeouts,
.error = dccp_error,
.can_early_drop = dccp_can_early_drop,
.print_tuple = dccp_print_tuple,
.print_conntrack = dccp_print_conntrack,
#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
.to_nlattr = dccp_to_nlattr,
.nlattr_size = dccp_nlattr_size,
.from_nlattr = nlattr_to_dccp,
.tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
.nlattr_tuple_size = nf_ct_port_nlattr_tuple_size,
.nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
.nla_policy = nf_ct_port_nla_policy,
#endif
#if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
.ctnl_timeout = {
.nlattr_to_obj = dccp_timeout_nlattr_to_obj,
.obj_to_nlattr = dccp_timeout_obj_to_nlattr,
.nlattr_max = CTA_TIMEOUT_DCCP_MAX,
.obj_size = sizeof(unsigned int) * CT_DCCP_MAX,
.nla_policy = dccp_timeout_nla_policy,
},
#endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
.init_net = dccp_init_net,
};
EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_dccp6);
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