From 2bc780499aa33311ec0f3e42624dfaa7be0ade5e Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Thu, 20 Mar 2008 15:15:55 +0100 Subject: [PATCH] [NETFILTER]: nf_conntrack: add DCCP protocol support Add DCCP conntrack helper. Thanks to Gerrit Renker for review and testing. Signed-off-by: Patrick McHardy --- include/linux/netfilter/nf_conntrack_dccp.h | 40 + include/linux/netfilter/nfnetlink_conntrack.h | 8 + include/net/netfilter/nf_conntrack.h | 2 + include/net/netfilter/nf_conntrack_tuple.h | 6 + net/netfilter/Kconfig | 10 + net/netfilter/Makefile | 1 + net/netfilter/nf_conntrack_proto_dccp.c | 816 ++++++++++++++++++ 7 files changed, 883 insertions(+) create mode 100644 include/linux/netfilter/nf_conntrack_dccp.h create mode 100644 net/netfilter/nf_conntrack_proto_dccp.c diff --git a/include/linux/netfilter/nf_conntrack_dccp.h b/include/linux/netfilter/nf_conntrack_dccp.h new file mode 100644 index 000000000000..40dcc82058d1 --- /dev/null +++ b/include/linux/netfilter/nf_conntrack_dccp.h @@ -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 + +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 */ diff --git a/include/linux/netfilter/nfnetlink_conntrack.h b/include/linux/netfilter/nfnetlink_conntrack.h index e3e1533aba2d..0a383ac083cb 100644 --- a/include/linux/netfilter/nfnetlink_conntrack.h +++ b/include/linux/netfilter/nfnetlink_conntrack.h @@ -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 */ diff --git a/include/net/netfilter/nf_conntrack.h b/include/net/netfilter/nf_conntrack.h index a3567a7a6d67..bb9fc852e973 100644 --- a/include/net/netfilter/nf_conntrack.h +++ b/include/net/netfilter/nf_conntrack.h @@ -20,6 +20,7 @@ #include #include +#include #include #include #include @@ -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; diff --git a/include/net/netfilter/nf_conntrack_tuple.h b/include/net/netfilter/nf_conntrack_tuple.h index 168c91754d89..bdeec3461384 100644 --- a/include/net/netfilter/nf_conntrack_tuple.h +++ b/include/net/netfilter/nf_conntrack_tuple.h @@ -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; diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig index daf5b881064d..c1fc0f1a641c 100644 --- a/net/netfilter/Kconfig +++ b/net/netfilter/Kconfig @@ -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 diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile index ea7508387f95..5c4b183f6422 100644 --- a/net/netfilter/Makefile +++ b/net/netfilter/Makefile @@ -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 diff --git a/net/netfilter/nf_conntrack_proto_dccp.c b/net/netfilter/nf_conntrack_proto_dccp.c new file mode 100644 index 000000000000..db88c5bcc5fd --- /dev/null +++ b/net/netfilter/nf_conntrack_proto_dccp.c @@ -0,0 +1,816 @@ +/* + * DCCP connection tracking protocol helper + * + * Copyright (c) 2005, 2006, 2008 Patrick McHardy + * + * 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 +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include + +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 "); +MODULE_DESCRIPTION("DCCP connection tracking protocol helper"); +MODULE_LICENSE("GPL"); -- 2.30.2