--- /dev/null
+/*
+ * 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");
projects / users / willy / pagecache.git / commitdiff